Title of Invention

SHAPE MEMORY POLYMER OR ALLOY OPHTHALMIC LENS MOLD AND METHODS OF FORMING OPHTHALMIC PRODUCTS

Abstract The invention relates to a shape memory polymer contact lens mold is formed from a sheet of a shape memory polymer in a press, an agile tool or by an agile tool formed by an inert gas at a temperature at or above the glass transition temperature which is there - upon cooled to below the glass transition temperature and removed therefrom.
Full Text SHAPE MEMORY POLYMER OR ALLOY OPHTHALMIC LENS MOLD
AND METHODS OF FORMING OPHTHALMIC PRODUCTS
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of U.S. Serial No. 09/649,635 filed August 28,
2000 entitled, "Deformable Iv.olds And Methods For Their Use In The Manufacture
Of Ophthalmic Lenses", and ihis application claims priority from provisional
application, Serial No. 60/263,986, filed January 24,2001, both applications are
incorporated herein by reference.
1. Field of the Invention
The present invention relates to the manufacture of ophthalmic products. In
particular, the invention provides molds for forming ophthalmic products, and
methods for forming the molds and ophthalmic products using the molds.
2. Background of the Invention
The use of ophthalmic lenses, including spectacle lenses, contact lenses,
intraocular lenses, and the likt for the correction of ametropia is well known.
Production of the lenses requi res the use of molds that impart the desired corrective
characteristics onto the lens sixfaces. Typically, a large inventory of molds is
required corresponding to eac.i sphere, add, and cylinder power, and combinations
thereof desired for the finished lens. Production and maintenance costs for the mold
inventory are high.
One current method of forming contact lenses is actually by a process that
has two molding steps. In the first molding step, male and female metal inserts,
fabricated by such methods as diamond point turning to ensure a very smooth
surface, are used to injection riold an ophthalmic lens mold comprising a pair of
mold members, typically male and female plastic molds, also referred to as back

curve and front curve lens molds. Then, in the second molding step, the contact lens
forming material is dosed between the back curve and front curve lens molds and the
contact lens is molded between the plastic: back and front curve. Typically the back
and front curves are not reused The production of an ophthalmic lens mold
typically comprising mold menbers in which a lens forming material is molded to
form an ophthalmic product, is the subject of the present invention.
The injection molding step just described to form the ophthalmic lens mold
members limits the types of materials that can be used to form the lens molds.
One method for production of lenses that attempts to eliminate the need for
large inventory molds is discibsed in United States Patent No. 6,026,204. In this
patent is disclosed the use of customized, heated dies, which utilize mechanical
fingers, alone or in combination with a metal surface, to impart the desired
corrective characteristics to a lens blank. This method is disadvantageous in that it
is unsuitable for the production of certain ophthalmic lenses, such as soft contact
lenses because soft contact lens materials are thermoset that cannot be deformed
with heat. Additionally, this method is disadvantageous in that molding the lens
material using a heated die r squires that the lens blanks' optical axis be perfectly
aligned with that of the die, which adds a great degree of difficulty to production of
the lens. Therefore, a need srists for n method to produce ophthalmic lenses with a
mold that permits reduction of lens inventory and which overcomes some or all of
these disadvantages.
Shape memory polymers (SMPs) were developed about 20 years ago and
have been the subject of commercial development in the last 10 years. SMPs derive
their name from their inherent ability to return to their original "memorized" shape
after undergoing a shape deformation. SMPs that have been preformed can be
deformed to any desired si ape below or above their glass transition temperatures
(Tg). If it is below the Tg, this process is called cold deformation. When

deformation of aplastic occurs above its Tg, the process is denoted as warm
deformation. In either case the SMP must remain below, or be quenched to below,
its Tg, while maintained in the desired thermoformed shape to "lock" in the
deformation. Once the defonnation is locked in, the polymer network cannot return
to a relaxed state due to thermal barriers. The SMP will hold its deformed shape
radefinitely until it is heated above its Tg, whereat the SMP stored mechanical strain
is released and the SMP returns to its preformed state.
Several polymer type s exhibit shape memory properties. Probably the best
known and best researched polymer type exhibiting shape memory properties is
polyurethane polymers. Goidon. Proc of First Intl. Conf. Shape Memory and
Superelastic Tech.. 115-120 (1994) and Tobushi et al., Proc of First Intl. Conf.
Shape Memory and Supereh.stic Tech.. 109-114 (1994) exemplify studies directed
to properties and application of shape memory polyurethanes. Another known
polymeric system, disclosed by Kagami et al., Macromol. Rapid Communication.
17, 539-543 (1996), is a class of copolymers of stearyl acrylate and acrylic acid or
methyl acrylate. Other SMP polymers; known in the art include articles formed of
norbornene or dimethaneoct;mydronaphthalene homopolymers or copolymers, set
forth in U.S. Patent 4,83 LO94, incorporated herein by reference.
SUMMARY OF THE INVENTION
In accordance with the present invention, an ophthalmic mold comprising a
shape memory polymer (SMP) or shape memory alloy (SMA) is provided. The
mold preferably comprises at least two mold members, preferably two mold
members, of which at least one mold member comprises a SMP or SMA. The mold
preferably comprises a front curve and a back curve, and is preferably used to form a
contact lens; however, the ophthalmic products that may be formed using the
ophthalmic molds of this invention include spectacle lenses, contact lenses,
interocular lenses or the like

Additionally, this invention provides a molding surface of an agile tool or as
referred to in U.S. Serial No. 09/ 649,635, a deformable mold comprising a SMP or
SMA; however, the focus of the description will be the formation of an ophthalmic
mold comprising an SMP or SMA.; however, the teachings herein can be applied to
the molding surface of the agile tool.
The mold of this invention comprising an SMP or SMA can be used to make
a lens and then re-shaped and reused to form another lens, thereby reducing the
amount of mold material consumed in a lens manufacturing facility. Additionally in
alternative embodiments, the molds formed by the methods described below can be
used to produce more varied contact lenses and even customized contact lenses at a
lower cost than if metal inserts had to be fabricated to make each mold member.
Additionally, by using the mold of this invention in manufacturing ophthalmic
products, a mechanical demol 1 step, used in the prior art to remove an ophthalmic
product molded within the mcld, may be eliminated and replaced with the step of
heating the mold comprising a SMP or SMA above its Tg to cause the mold to
deform, at which time the ophthalmic product can be removed from the mold
without the mechanical demo ld step.
Further, the molds of this invention are not formed by injection molding at
high temperature, i.e. as high as 300°C, and elevated pressure, thereby providing
new types of materials that can be used to make the devices, that shape the
ophtfialmic molds. By fonnng molds by methods other than injection-molding,
different mold forming materials, and methods can be used to make the molds.
Additionally, if the agile toe ls described herein are used to make the molds a full
prescriptive range of lenses can be produced while reducing the number of molds
required, and eliminating all the injection-molding tools required to do the same.
Further, the molds of the in vention may be used in a method for the delivery of
customized ophthalmic lenses to a lens wearer.

BRIEF DESCRIPTION OF THE^RA WINGS
The present invention wi .1 be better understood by reference to the following
drawings of which:
Figure 1 is an ophthalmic lens mold of this invention.
Figure 2 is a sectional ekvational view of a first mold member forming
press;
Figure 3 is a sectional el« vational view of a second mold member forming
press;
Figure 4 is top view of a shape memory polymer or alloy holder;
Figure 5 is a sectional ekvational view of the holder of Figure 4 shown
holding a shape memory polymer or alloy sheet.
Figure 6 is depiction of an alignment jig utilized in the formation of mold
members employing a press or an agile tool;
Figure 7 is a sectional elevational view of the first mold member forming
press operating on a shape memory polymer or alloy sheet;
Figure 8 is a sectional ele vational view of the second mold member forming
press operating on a shape memory polymer or alloy sheet;
Figure 9 is a sectional els vation view of the disposition of an SMP or SMA
sheet in an agile tool with a core element prior to mold member formation;
Figure 10 is a top plan visw of the agile tool of Fig. 9;
Figure 11 is a magnified, cross-sedional view of an agile mold;
Figure 12 is a sectional eievation view of a precast mold;
Figure 13 is a compression fixture;
Figure 14 is an ophthalmic mold of this invention in an agile tool;
Figure. 15 is a flow diagiam of a process for making and using the mold of
the invention.
The present invention uniquely employs shape memory polymer (SMP) or or
shape memory alloys (SMA), pr rferably shape memory polymers, as the material of
construction of a mold in the manufacture of ophthalmic products, preferably

contact lenses. The molds may comprise one or multiple pieces or members.
Preferably, the molds comprise two mold members of which at least one mold
member comprises a SMP or S MA. The terms "ophthalmic lens mold", "ophthalmic
mold", "mold" and "mold member" "firj;t mold member", "second mold member",
"front curve", "front curve lens; mold", "back curve", "back curve lens mold", will
be used to refer to the molds 01 parts of the mold of this invention used to form
ophthalmic products.
Shape memory polyma-s and alleys having the properties discussed earlier
may be utilized in the formatioi of the molds. Thus, shape memory polymers,
which include polyurethane po ymers, norbomene homopolymers and copolymers
of norbornene and alkylated, cyano, alkoxylated, mono- or diesterified imides or
carboxylic acid derivatives may be employed. In addition, the copolymer may
include, as a comonomer, dimethaneoctaiydronaphthalene (DMON)- Alternatively,
hompolymers of DMON, as well as copolymers of DMON and styrene,
acenaphthalene or dicyclopentadiene, which may be hydrogenated or halogenated,
may be employed. Additionally, the SMP may comprise copolymers of stearyl
acrylate, acrylic acid or methyl acrylate
i The SMP used to form the ophthalmic mold is preferably a thermosetting
resin, cured by radiation or heal.
Shape memory alloys may also be used to form the molds of this invention to
be used for forming ophthalmic products. Such shape memory alloys include
Nitinol, which is a nickel and tiianium alloy (NiTi), copper, aluminum and cobalt
alloys and copper-nickel-titanium-aluminum alloys. The use of shape memory
polymers is preferred over shape memory alloys, therefore, the description below
may refer to the shape memory polymers and not the shape memory alloys;
however, that is not meant to be limiting, and the term shape memory alloy may be
added where ever the term shap e memory polymer appears.

Although the above discussed shape memory polymers are within the
contemplation of the present invention, it :is preferred that the shape memory
polymer, employed in the formation of the mold of the present invention, be a new
SMP, a copolymer of styrene and a vinyl compound other than styrene. This SMP is
described in copending and conc urrently filed application, VTN-576, entitled
"Shape Memory Styrene Copolymer", which is incorporated herein by reference.
The preferred SMP is pre spared from a reaction mixture which includes, in
addition to styrene and the vinyl compound, a crosslinking agent and an initiator,
and an modifying polymer.
The second monomer, a /inyl compound other than styrene, is preferably
vinyl neodecanoate, vinyl benzoate, vinyl propionate, vinyl stearate, a
methylstyrene, which may be a mixture, 3 -methylstyrene or 4-methylstyrene, a vinyl
pyridine, which may be a mixtuie, 2-vinyl pyridine, 3-vinyl pyridine or 4-vinyl
pyridine, vinyl laurate, vinyl butyrate, vinyl acetate, vinyl stearate, vinyl 2-furate,
vinyl phenylacetate, vinyl carba/,ole, 4-vmylbenzyl acetate, 4-vinylbenzoic acid,
vinyl methyl sulfone, vinyl octadecyl ether, vinyl isooctyl ether, N-vinyl-2-
pyrrolidone, N-vinyl-N-methyla;etamide, 1-vinylimidazole, N-vinylfonnamide, N-
vinylcaprolactam, vinyl azolactcne, N-vinylurea, 4-(vinyloxy)butyl stearate, 4-
(vinyloxy)butyl benzoate, 4-(viryloxymetnyl)cyclohexylmethyl benzoate, methyl
acrylate, methyl methacrylate, b atyl acrylate, t-butyl acrylate, butyl methacrylate, t-
butyl methacrylate, hexyl acryla:e, acrylic acid, methacrylic acid, benzyl acrylate,
benzyl methacrylate, 2-n-butox} ethyl meitliacrylate, 2-cyanoethyl acrylate,
cyclohexyl acrylate, cyclohexyl methacrylate, decyl acrylate, dicyclopentenyl
acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate,
dodecyl acrylate, dodecyl methacrylate, 2-ethoxyethyl methacrylate, 2-ethylhexyl
acrylate. ethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
isobornyl acrylate, isobomyl methacrylate, 2-(2-methoxyethoxy)ethyl acrylate, 2-(2-

methoxyethoxyl)-ethyl methacrylate, 2-me:thoxyethyl acrylate, 2-methoxyethyl
methacrylate, 2-methoxypropyl icrylate, 2-methoxypropyl methacrylate, octyl
methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, phenyl
acrylate, 2-phenylethyl acrylate. 2-phenylethyl methacrylate, phenyl methacrylate,
propyl acrylate, propyl methacrylate, stearyl acrylate, stearyl methacrylate, 2,4,6-
tribromophenyl acrylate, undecyl acrylate or undecyl methacrylate.
Of the vinyl compounds preferred for use in the reaction mixture of the shape
memory polymer of the present invention, vinyl neodecanoate, vinyl benzoate, vinyl
propionate, vinyl stearate, a methylstyrene, 4-(vinyloxy)butyl stearate or a vinyl
pyridine are particularly prefen ed.
The crosslinking agent of the shape memory polymer reaction mixture is
multifunctional, that is, the cro sslinking agent is a compound that has a
polymerizable functionality of at least 2. Difunctional crosslinking agents are
preferred. Crosslinking agents within the scope of the present invention include
diallyl furnarate, diallyl diglyc si carbonate, allyl methacrylate, diallyl phthalate,
diallyl suberate, diallyl tetrabromophthatate, diethylene glycol diacrylate, diethylene
glycol dimethacrylate, diethylene glycol divinyl ether, N,N'-
dimethacryloylpiperazine, 2,2 dimethylpropanediol dimethacrylate, dipentaerythritol
pentaacrylate, dipropylene glycol dimethacrylate, di-rrimethylolpropane
tetraacrylate, divinyl glycol, divinyl sebacate, glycerol trimethacrylate, 1,5-
haxadiene, 1,6-hexanediol diacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol
dimethacrylate, N,N'-methylenebismethacrylamide, 1,9-nonanediol dimethacryalte,
pentaerythritol tetraacylate, pemtaerythrtol triacrylate, pentaerythritol triallyl ether,
1,5-pentanediol dimethacryla:e, poly(j?i'opylene glycol) dimethacrylate, tetraethylene
glycol dimethacrylate, Methylene glycol diacrylate, triethylene glycol
dimethacrylate, triethylene glycol divinyl ether, 1,1,1-trimethylolethane
trimethacrylate, 1,1,1-trimetlylolpropane diallyl ether, 1,1,1-trimethylolpropane
triacrylate, 1,1,1-trimethylolptropane trimethacrylate, tripropylene glycol diacrylate,

1,2,4-trivinylcyclohexane, di vinyl benzene, bis(2-methacryloxyethyl)phosphate, 2,2-
bis(4-methacryloxyphenyl)p-opane, 1,3-butanediol diacrylate, 1,4-butanediol
diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,4-
butanediol di vinyl ether, l,4-cyclohex;mediol dimethacrylate, bis[4-
(vinyloxy)butyl]isoph1halate,bis[4-(vinyloxymethyl)cyclohexylmethyl]glutarate,
bis[-(vinyloxy)butyl]succin£ te, bis((4-((-
vinyloxy)methyl)cyciohexyl )methyl)isophthalate, bis(4-
(vinyloxy)butyl)terephthalae, bis[[(4-
[vinyloxy)methyl)cyclohexyl] methyl] terephthalate, bis[4-vinyloxy)butyl]adipate,
bis[4-(vinyloxy)butyl] (methylenedi-1,4-phenylene)biscarbamate, bis[4-
(vinyloxy)butyl] (4-methyl-l,3-phenylene)biscarbamate, bis[4-(vinyloxy)butyl] 1,6-
hexanediylbiscarbamate or ris[4-(vmyloxy)butyi] trimellitate.
Of these preferred crosislinking agents, divinyl benzene, bis[4-
(vinyloxy)butyl]terephthala te and bis[[4-[(vinyloxy)methyl]cyclohexyl]methyl
terephthalate are particularly preferred. Of these, divinyl benzene is even more
particularly preferred as the crosslinking agent.
The initiator of the eaction mixture may be a free radical or an ionic
initiator. Free radical initiators within the scope of the present invention include
organic peroxides and azo compouncs. Although any of the commercially available
organic peroxides may be utilized, tert-butyl peroxide, tert-butyl hydroperoxide,
benzoyl peroxide, dicumyl peroxide and lauroyl peroxide are particularly preferred.
Similarly, although any co nmercially available azo initiating compounds may be
utilized, 2,2'-azobisisobutyronitrile is particularly preferred. The ionic initiators are
preferably cationic initiators. Preferred cationic initiators include boron trifluoride,
boron trifluoride diethyl elherate, ahiminum trichloride and tin (IV) chloride.

As stated above, the S VIP reaction mixture may include a fifth, optional
component. This fifth component of this shape memory polymer reaction mixture is
optional. That optional component is a modifying polymer. The modifying polymer
acts as a viscosity adjustor and, additionally provides the requisite toughness to the
resultant shape memory polymer.
The modifying polymer of the shape memory polymer reaction mixture is a
thermoplastic polymer that is compatible with the polymer formed by the reaction
product of styrene and a vinyl compound. Preferred compatible polymers include
olefin polymers and styrene polymers. Particularly preferred compatible polymers
include polystyrene, poly(styn;ne-co-butadiene), polyethylene and polypropylene.
Of these, polystyrene is particularly preferred as the modifying polymer in the shape
memory polymer reaction mixture.
The constituents of the shape memory polymer reaction mixture are present
such mat the styrene monomei constituent represents between about 30% to about
95%, the vinyl monomer conslitutes between about 5% and about 60%, the
crosslinking agent constitutes between about 0.5% and about 5%, the initiator is
present in a concentration in the range of between about 0.1% and about 4% and the
modifying polymer, if present, represents between about 0.5% and about 60%, all of
the above recited percentages being by weight based on the total weight of the shape
memory polymer reaction mixure.
Preferably, the constituents of the: shape memory polymer reaction mixture
are present in the following concentration ranges, again reported as percentage by
weight, based on the total weight of the reaction mixture: styrene monomer, about
40% to about 85%; vinyl monomer, about 5% to about 20%; crosslinking agent,
about 0.6% to about 3%; initiaior, about 0.5% to about 3%; and modifying polymer,
if present about 5% to about 50%.

More preferably, the co istituents of the shape memory polymer reaction
mixture include between about 50% and about 80% styrene monomer; between
about 5% and about 14% vinyl monomer; between about 1% and about 2.5%
initiator; and, if present, between about 10% and about 40% modifying polymer. As
previously, these percentages are by weight, based on the total weight of the shape
memory polymer reaction mixture.
The shape memory polymer reaction mixture is polymerized by reacting the
mixture at a temperature in the range of between about 20°C and about 150°C and a
pressure in the range of between about 14.7 psi and about 50 psi over a time period
in the range of between about 1 seconds and 4 days to produce a crosslinked shape
memory polymer.
In a preferred embodiment, the polymerization reaction, to produce the
thermosetting shape memory p jlymer of the present invention, occurs at a
temperature in the range of between about 50°C and about 110°C and a pressure in
the range of between about 14.7 psi and about 25 psi over a period of between about
1 minute and 3 days.
More preferably, the pc lymerization reaction conditions, used to form the
shape memory polymer sheet t iat is formed from the shape memory polymer
reaction mixture, are as follow,.: a temperature in the range of between about 65°C
and about 75°C, a pressure of about 14.7 psi for a period of between about 4 hours
and about 1.25 days.
The mold of this invemion comprising SMP and SMA can have any shape
useful for forming an ophthalmic product.
One embodiment of amold of this invention is shown in Figure 1. Figure 1
shows a mold 110 comprising a first mold member 112 and a second mold member

114. The mold 110 is shown with the first and second mold members 112,114
assembled to form a cavity 11:5 into which a lens forming material is preferably
dosed prior to assembly of the mold members. After assembly of the mold members
to form the mold 110, the lens forming material is preferably cured or crosslinked to
form an ophthalmic product. 5 urface 116 of the first mold member 112 and surface
115 of the second mold member 114 are optically critical surfaces (also referred to
herein as the optical forming surfaces) of the mold, because they are the surfaces of
the mold that contact the lens farming material, and those surfaces 115,116 impart
the optical characteristics to the ophthalmic product formed within the mold 110.
By "optical characteristics" is neant one or more spherical, aspheric, toric,
cylindrical curvature, or other wavefront corrections, and the like and combinations
thereof.
The first and second meld members 112,114 are shown comprising optional
flanges 118, 117. As shown, the mold 110 is suitable for making a contact lens. For
the formation of contact lenses the first mold member 112 may be referred to as the
front curve lens mold or front c irve, and the second mold member 114 as the back
curve or back curve lens mold, md the mold 110 may be referred to as a lens
assembly. In the prior art the fnnt curves: and back curves are often made by
injection molding, as described in the "Background of the Invention."
This invention will be described with reference to the preferred embodiment
used in the formation of contact lenses; however, it is understood that the molds of
this invention can be used to make other ophthalmic products.
The fabrication of the molds comprising a shape memory polymer is
accomplished by methods that fcike advantage of the unique properties of these
polymers. In one preferred embodiment the shape memory polymer contact lens
mold is prepared in a hot forming method in which a sheet, preferably disc-shaped,
however various shapes can be used, of a shape memory polymer is formed into the

desired contact lens mold shap s, corresponding to the desired contact lens to be
formed using the mold, by means of a press. The term "press" is used to describe a
device used to shape the SMP. The press comprises at least one surface that
contacts the SMP.
One embodiment of the press used in the present invention is as shown in
Figures 2 and 3 constitutes a second mold member forming press or second press 1
and a first mold member forming press or first press 7. The second press 1 includes
a base curve element 2 and a cc re element 4. The first press 7 includes a front curve
element 6 and a core element 8C The base curve element 2 and front curve element 6
may be formed by diamond point turning and/or polishing of an appropriate metal,
e.g. brass. Alternatively, the mJtal may be metal plated, e.g. nickel plated.
Preferably, the smoothness of the base curve element 2 and front curve element 6 is
such that the surface roughness of these elements is no more than a root mean square
roughness (RMS) of about 20 nanometers. It is emphasized that the base curve
element 2 and front curve element 6 of the press 1,7 define the surfaces 115,116 of
the second and first mold memt ers 114,112, respectively, that are the optically
critical surfaces of the mold because those surfaces of the mold contact the lens
forming material molded into tie lens. Although smooth surfaces 3 and 5 of the
base curve elements 2 and front curve element 6, respectively, are depicted as
spherical, they may be toric shaped, bifocal shaped, shaped to correct for wavefront
aberrations, or another shape rel leering other contact lens designs.
The core elements 4,8 of the second and first mold forming presses 1,7 are
depicted in the drawings as solids. The cere elements 4,8 are preferably made of
elastomers, or metals, or a combination of these materials. The core elements 4,8
may comprise the same metals tsed to make the front curve element 6 and base
curve element 2. The surface oi the core elements 4,8 typically are not subject to
any smoothness requirement.

In another embodiment, the core element is not a solid element, but is
provided by gas pressure or the like. In a preferred embodiment the gas is air, with
the proviso that the gas is inert insofar as it does not react with the SMP material.
Alternatively, a vacuum may be pulled OE. the base curve element 2 or front curve
element 6 sides of the presses tc pull the sihape memory polymer sheet against the
base curve element or front curve element The key is the pressure differential
across the sheet pushing or pullmg the sheet against the base curve element or front
curve element.
In operation, for example in reference to the second mold member forming
press 1, a shape memory polyner- or alloy sheet 12 is formed into a second mold
member while being held by a shape memory polymer or alloy holder 10, (shown in
Figures 4 and 5) between the core element 4 and the base curve element 2 having
smooth surface 3. The SMP sheet is preferably a flat sheet, and shown as round;
however other shapes may be used. The SMP sheet 12 is inserted into holder 10 as
shown in Figures 4 and 5. The iiolder 10 is accommodated in an alignment jig 15
shown in Figure 6. Holder 10 effectively holds the SMP sheet 12 at its edges 33 so
that the edges 33 of the SMP shset 12 form the flange 117 of the mold member 114.
The holder 10 maintains the edges 33 of tie SMP sheet in fixed position while the
center portion 34 of the sheet 12 is shaped in the form of a mold member 114. The
holder 10 holds SMP sheet 12 without restricting the deformation of the center
portion 34 of the sheet 12. Nex;, the base curve element 2 and core element 4 are
introduced into the alignment jig 15 discussed below. Prior to any contact with the
SMP sheet, the temperature of the SMP sheet is raised to or above the glass
transition temperature of the SMP. The SMP may be heated to a temperature above
its glass transition temperature by exposing the SMP sheet to radiation, such as IR
radiation, a hot gas, or by conduction (heating the holder). The SMP temperature
preferably should be heated to and maintained within a few degrees above the glass
transition temperature because further heating will likely not change the modulus
(stiffness) of the material and would only increase the heating time and energy

requirements. After heating ths SMP, the base curve element 2 is pressed into core
element 4 under appropriate pressure. After a short period of time, the temperature
of the press 1 is thereupon reduced to below the SMP glass transition temperature
for a sufficient time period for the SMP to drop to a temperature below its glass
transition temperature. The sample may be cooled by, for example, removing the
heating source only, removing the heating source and exposing the sample to a cool
gas stream, or by removing the heating ;source and running a cooling fluid through
the base curve element 2. The JIMP temperature should be reduced to a few degrees
below the glass transition temp erature. Further cooling will likely only increase the
cooling time. At this time, the holder 10 is removed from the jig 15, and the
deformed SMP sheet 12, in the form of a second mold member 114, is removed
from the holder 10.
A similar procedure takes place in. forming the first mold member 112. That
mold member is identically pre Dared except that the diamond point turned, polished
or nickel plated coated surface 5 of the front curve element 6 cooperates with a core
element 8 of the front curve forming press 7 to form a first mold member 112 having
an optically critical surface 116 as shown in Figure 1.
The above mold forming process ;.s best accomplished employing an
alignment jig 15. Alignment jig 5 15 includes a top element 22, and a bottom element
23 defining a groove opening 24 therebetween. Top and bottom elements 22 and 23
have an aligned opening 25. The holder 10 is accommodated in the groove opening
24. Holder 10 includes an opening 11 which is aligned in alignment jig 15 so that
openings 11 and 25 are in regisier. The press elements fit into opening 11 and 25 so
that the press elements are aligned with respect to each other and with respect to the
SMP holder 10. The second meld member is shown being formed in press 1 within
jig 15 in Figure 7. The first mo d member is shown being formed in press 7 within
jig 15 in Figure 8.

The elements of the presses and ihe elements of any of the other
embodiments described below for forming the mold of this invention, may be
brought into contact for purposes of forming the mold using any suitable contacting
means including, without limitation, stepper motors, screw drives, or the like, and
combinations thereof.
Another method of fabricating an ophthalmic mold comprising a shape
memory polymer is by use of an agile deformable mold, as described in the parent
application U.S. Serial No. 09/549,635. To avoid confusion between the mold that
is being claimed herein and the agile mold described in the parent application and
further described here, the agile mold will be referred to herein as an "agile tool".
The agile tool preferably is use i to make an ophthalmic mold or an ophthalmic mold
member, which is then used to make an ophthalmic product. The agile tool
comprises a molding surface th it is capable of being deformed. The molding
surface of the agile tool is defoimed by adjustment means.
One type of agile tool useful in making the molds of this invention comprises
a layer which may be composite of materials or layers of which the non-molding
side of the layer or non-molding surface of the agile tool is contacted with the
adjustment means and the molding side of the layer or molding surface of the agile
tool contacts the SMP that forms the ophthalmic mold. At least a portion of the
molding surface of the agile tool is capable of being deformed and has a first shape
that may be of any shape, but cc nveniently is of a concave or convex shape having a
first radius of curvature R1. This deformable portion of the molding surface of the
agile tool is capable of being de :brmed by action of the adjustment means preferably
against the non-molding surface of the agile tool so that the deformable portion
assumes a second shape that is desired to be imparted to at least a portion of a
surface of the ophthalmic mold 10 be produced in the agile tool. The second shape
of the molding surface of the agile tool imparts the desired optical characteristics to
the mold.

As stated earlier, "optical characteristics" is meant one or more of spherical,
aspheric, tone, or cylindric cmvature, or other wavefront aberrations and the like
and combinations thereof. Theoptical characteristic imparted will depend on the
aberrations of the lens wearer's eye desired to be corrected. The agile tool is
suitable for producing molds to produce ophthalmic products for correction of any
wavefront aberration of the eye, meaning any departure from a spherical wavefront.
These aberrations include, witiout limitation, astigmatism, defocus, coma, spherical
aberrations, distortion, and the like. These aberrations also may be defined using
Zemike polynomials.
The layer and/or at least the molding surface of the agile tool may be formed
by any material capable of being deformed, capable of withstanding the stresses
imposed by the SMP or SMA mold manufacturing process, and capable when
deformed of mamtaining a shape suitable for imparting the desired optical
characteristics to the mold to be formed using the agile tool. The surface of the agile
tool must be deformable and non-reactive with the SMP or SMA used to form the
mold member in the agile too.. Suitable agile tool layer or molding surface
materials include, without limitation, metals, polymers, metalized polymers and the
like and combinations thereof Exemplary of these materials are aluminum, gold,
brass, and nickel metals, poly Dlefin polymers including, without limitation,
polyethylene and polypropylene, polyethylene terphthalate, silicone polymers,
electro-active polymers such is polyarchies, polypyrroles, ion exchange polymer
metal matrix compositions and the like, shape-memory polymers such as segmented
polyurethanes, and any of the other SP's described earlier, ceramics such as silicon
carbide, shape-memory alloy:; such as nitinol, and the like and combinations thereof.
These materials are commercially available or methods for their production are
known.

The agile tool molding surface preferably has an optical quality surface
finish if it contacts the optically critical surface(s) of the SMP or SMA mold. The
non-molding surface of the ag Je tool need not have an optical quality finish.
However, the non-molding suilace of the agile tool must be sufficiently pliant,
flexible, and durable to enable its repeated contact, and action upon it by, the
adjustment means, and may be formed from an elastomer or the like.
Preferably, the molding surface of the agile tool, singly or in combination
with the non-molding surface of the agile tool, is in the form of a membrane, more
preferably a polymeric membrane. In a most preferred embodiment, the molding
surface is a membrane of a su,e and shape suitable for production of a soft contact
lens and is about 0.5 to about 5000, preferably 1 to about 1000 microns in thickness.
Adjustment means may contact the non-molding surface of the agile tool of
the invention under conditions suitable to deform the defonnable portion of the
molding surface of the agile tool to the desired shape. Adjustment means may be
any means capable of manipulating and deforming the deformable portion of the
molding surface of the agile tool to the degree necessary to obtain the desired
configuration of the molding surface of the agile tool. Examples of such adjustment
means include, without limitation, fluids, micro-actuators, such as piezo-electric,
micro-motorized, or hydrauli; micro-actuators, magneto-restrictive actuators,
electro-static actuators, electio-active polymers, and the like that move in response
to an input signal. For example, by vaiying the voltage applied to a series of piezo-
electric micro-actuators, the deformable portion of the molding surface may be
displaced so that it assumes i. desired shape. An array of pins or concentric tubes
wherein each pin or tube is c ipable of having its height individually adjusted,
relative to a datum and locked into place to thereby form the desired shape can be
used as the adjustment means.

In embodiments in which micro-actuators in the agile tools are used to form
the molds of this invention, spacmg of the actuators may be determined by the
resolution requirement of the surface of the mold to be formed by the agile tool and
ultimately the ophthalmic product to be formed by the mold. The resolution
requirements will be determined by the features desired to be imparted onto the
surface of the mold and/or lensC The adjustment means may be used in combination
with heat to alter the shape of tie molding surface of the agile tool. The use of heat
will be required if the molding surface of the agile tool also comprises an SMP or
SMA. The Tg of the SMP or SMA that is used as the deformable surface of the agile
tool should be higher than that of the SMA used to form the ophthalmic lens mold.
Figs. 9 and 10 show an exemplar/ agile tool 210 used to make a mold of the
invention comprising shape memory poly/mer or alloy. The agile tool has a layer
220 which may be a single material or may comprise several materials or layers
having a concave molding surf ace 213 and convex non-molding surface 214.
Enclosure 211 is shown suppoiting agile tool 210. An array of micro-actuators 218
is shown contacting non-molding surface 214, which acts as the adjustment means.
Molding surface 213 has a portion 215 that is deformable and of a first shape of a
radius of curvature R1, which radius will change upon actuation of the adjustment
means. Additionally, as shown, molding; surface 213 has areas 216 and 217 each of
a fixed radius of curvature. Area 216 is continuous with and extends around portion
215. Area 217 is continuous with and extends around area 216. The mold to be
formed by areas 216 and 217 are those that will form the portions of the lens outside
the optical zone of the lens. ID an alternative embodiment, areas 216 and 217 also
may have unfixed radii of curvature and be subject to the adjustment means. When
the plurality of actuators 218 are actuated and moves non-molding surface 214, this
causes the deformable portion 215 of molding surface 213 to be deformed to the
desired shape.

The agile tool 210 shov/n in Figs. 9 and 10 is preferably used to form a
second mold member or back c urve. Foi purposes of molding a mold member, a
core element 4 complementary to agile tool 210 may be used, as shown in Figure 9.
Another agile tool (not shown) can be used with a complementary core element (not
shown) to form the first mold member or front curve, similar to the use of the pair of
presses shown in Figures 1 and 2 to make the pair of mold members. However, a
single agile tool that can widely adjust its molding surface from convex to concave
could be used in combination with one or more core elements to form both mold
members, if desired.
After the actuated surface 213, whose shape is controlled by adjustment
means 218, is set to the desired shape, the SMP material 12, which may be flat or
preformed into spherical or toric shape, is introduced to the agile tool 210 in a
manner that may be analogouswith the method employed in the press process. That
is, an alignment jig 15, in which an SMP holder 10 is disposed, is utilized to dispose
the SMP 12 between a core element 4 and the molding surface 213. Upon
disposition of the SMP 12 into ;oo agile tool 210, and after the temperature of the
SMP is raised to or above the SMP glass transition temperature, the core element 4,
presses the SMP 12 into contacl with the actuated surface 213, at the requisite
pressure. The temperature is then reduced below the SMP glass transition
temperature, preferably to ambient temperature, until the temperature of the SMP
decreases below its glass transit on temperature, and then core element 4, is lifted
from the SMP 12. Then, SMP 12, in the shape of a contact lens mold half, is
removed from agile tool 213. The same process may be repeated to form a first
mold member using an agile tool shaped to form the first mold member (not shown).
Alternatively, instead of or in addition to, setting the actuated surface 213,
whose shape is controlled by adj ustment means 218, to the desired shape prior to
introduction of the SMP sheet irto the agile mold, the adjustment means 218 may be
changed while the SMP sheet is in contact with the agile mold.

In alternative embodimeits for mEiking the mold of this invention using an
agile tool, the core element 4 as shown in Fig. 9 may be replaced by a stream of gas
(not shown), or by a vacuum (not shown) pulled on the surface 218 of the sheet 12.
In embodiments in which gas pressure is used to press the sheet 12 against the
molding surface 213, so that sheet 12 takes the shape of the molding surface 213, the
optical forming surface of the mold may be formed on either surface 218 or 219 of
sheet 12. If the optical forming surface is formed on surface 219 of sheet 12, the
layer 220 of the agile tool 210 may or may not be used. (Actually if the surface
roughness of the adjustment mains without any layer is low enough, although this
would complicate the fabrication of the adjustment means, the layer of the agile
mold would be optional even if he optical forming surface of the mold is the surface
pressed against the adjustment means.) It is preferred that in the embodiments using
gas pressure as the core element that the optical forming surface of the SMP 12 will
not contact any solid surface that will impart its surface imperfections to the optical
forming surface of the mold and thereby to the lens made using the mold. The
optical forming surface of a mold, that is, the surface of the mold that contacts the
lens forming material, preferably has a root mean square surface roughness of no
more than about 20 nanometers. It is presently believed that the methods that use
gas pressure as the core element and. during which the optical forming surface is
not contacted by any solids, proydde the smoothest optical forming surfaces, because
surface smoothness of the result mg mold member is equal to that of the starting
material (sheet 12), which typicsilly is well below 20 nm RMS.
Note that in me embodiment employing a press wherein the core element
was provided by air or gas pressure, as described earlier, the optical forming surface
was not contacted by the air or gas; however, that embodiment could be modified to
provide that the optical forming surface could be the one contacted by the air or gas
to provide the benefits just described. Additionally in any of these embodiments
that use a stream of gas, that preferably is inert to the SMP, the gas stream may be

used to heat and/or cool the SMP in the process of forming the mold comprising
SMP. The preferred gas for these embodiments is air. However, if air reacts with
the SMP employed, then a low cost inert gas, such as nitrogen, may be alternatively
utilized.
As described earlier for 'he other embodiments, in specific operation, the
agile die is preadjusted, by spec fie adjustment of adjustment means, to the desired
shape of the SMP sheet 12 when formed into a mold member. The SMP sheet 12
may be disposed in a holder 10 and in an alignment jig 15. The jig is used to center
the SMP sheet 12 with respect to the agile die. The SMP sheet, clamped at its edges
in holder 10, which is disposed in alignment jig 15, is heated above its glass
transition temperature. The healing step may be provided by conduction, i.e. direct
heating, by such means as providing the cliamp with heating means; by convection,
i.e. using a heated gas; or by radiation, e.g. infrared (ER) heating. Of these heating
means, radiation heating, because of the speed at which the SMP maybe heated, is
preferred. The SMP material is leated at or above the transition temperature, is
subjected to a high pressure iner: gas stream, by application of a vacuum or both.
The pressure and velocity of the gas stream is such that the SMP sheet 12 assumes
the shape defined by adjustment means or molding surface, if present, transferred to
the side of the SMP 12 exposed :o the gas stream. In an alternate embodiment, a
vacuum source, may supplemem or replace the gas stream. Upon formation of the
desired shape, the SMP sample is cooled to ambient temperature, by removing the
heating source, to "lock-in" the desired shape. The clamped edges, which form a
flange for the contact lens mold nalves, is released and the formed SMP contact lens
mold is removed.
In another embodiment of this invention, the lens molds comprising SMP or
SMA may be formed in an agile tool comprising an adjustment means that is a
mechanical magnetic field deformation means. In this embodiment, a first magnetic
surface contacts the layer of the igile tool. Preferably, the magnetic surface is of a

shape that is complementary to the layer of the agile tool. The magnetic surface
may be constructed of any magnetic material capable of withstanding the molding
process environment and, preferably, is of a material that is capable of being
physically or chemically bondaed to the non-molding surface of the agile tool.
Suitable materials include, without limiration, magnetic ferrous steels, cast or
sintered alnicos, bonded or siitered ferrites, lodex, P-6 alloy, cunife, cunico,
vicalloy, remalloy, platinum :obalt, cobalt-rare earth blends, and the like and
combinations thereof.C Alternatively, with the proper selection of materials the
magnetic surface can be the molding surface.
A second magnetic surface is brought into sufficient proximity to the first
magnetic surface to exert a r lagnetic force upon the first surface that is effective to
impart a desired shape to the first magnetic surface and, through that first molding
surface, to the molding surface of the agile tool. The second magnetic surface may
be positioned by any converient positioning means including, without limitation, a
robotic arm, a gripper, an ac justable mechanical arm, or the like or a combination
thereof. Either or both the first and second magnetic surfaces may be formed of a
series of electromagnets.
i Fig. 11 shows an alternative embodiment of the invention in which the
adjustment means of an agile tool used to form a mold member of the invention is a
magnetic field deformation means. Molding surface 213 has deformable portion
215. Non-molding surface 214 is in. contact with it first magnetic material 221.
Second magnetic material .122 is brought into proximity of first magnetic material
221 by mechanical arm 223, which arm is movably mounted so that it can be
manipulated in the directions shown by the arrows. A magnetic force is exerted on
material 221 by material 2.22 resulting in the deformation of material 221 and
deformable molding surface 215. Although not shown the agile tools, preferably
have a feed back mechanism, such as an interferomic technique, used to feed

information back to the adjustment means regarding the position and shape of the
molding surface, the non-molding surface, or both.
In another embodiment, an ophtlialmic mold comprising an SMP may be
fabricated to incorporate intriiLsic actuators. Intrinsic actuators are discrete areas of
the mold, comprising the SMI' that can be activated by heat that can be individually
applied to the intrinsic actuators to make precise changes to the surface of the mold
used to form the ophthalmic p roduct. The precise changes are controlled by the size
of the intrinsic actuators, the composition of the intrinsic actuators, and the number
of intrinsic actuators heated. One method of preparing the SMP material having
intrinsic actuators is illustrated in Figures 12,13 and 14. In Fig. 12, the SMP is cast
into a precast mold 70 to form a preform 79 formed within the precast mold 70.
(The method differs from the other embodiments as described which started out with
a sheet of SMP that had been oast in a flat mold, preferably a two sided flat mold
having at least one optical quality surface to form the sheet (i.e. a flat preform.) The
precast mold 70, as shown provides a spherical preform 79, however other shapes
can be formed instead. The precast mold 70 comprises two parts, the first part 75
and the second part 76. The first and second parts 75 and 76 can comprise any
materials, e.g. metal or glass; however., if it is preferred to provide an optical surface
to the preform 79 at least on the surface contacting the first part 75, therefore metal
or glass having an optical surface finish should be used to form the first part 75 of
the precast mold 70. The seccnd part 7(5 has an array or some assembly of small
features 71 that provide for projections 72 on the surface of the preform 79. The
projections 72 are present on the surface of the preform 79 opposite the surface that
provides the optical forming s jrface of Ihe ophthalmic mold that the preform 79 will
be modified to become. The j rejections 72 can have dimensions extending from a
few microns to hundreds of microns. Once the preform 79 has been formed in the
precast mold 70, it is removed and further processed as shown in Fig. 13.

The preform 79 is then preferably placed in a compression fixture 81 having
a bowl-shape indentation 83 similar to the shape of the preform 79 into which the
preform is placed. The flange 77 of the preform 79 would be clamped to the fixture
81 by clamping means (not shewn). The SMP preform will be heated to a
temperature above its glass transition temperature and then compacted between the
fixture 81 and a pestle 82 shaped to complement the fixture 81, both of which may
be spherical, or toric or otherwise shaped. The fixture 81 and pestle 82 compress the
projections 72 while retaining tlie overall shape of the preform 79. The preform 79
would be subsequently cooled to below it:; glass transition temperature, and removed
from the fixture 81. The projections 72 would no longer project as far from the
surface of the preform 79, but would act as intrinsic actuators 85 in the preform 79
that would be used to shape the optical forming surface 84 of the preform 79 as
shown in Fig. 14.
The pestle 82 could be termed from a metal (e.g. brass) that had been
diamond point turned or glass so that it has; a surface roughness of 20 run RMS, or
better. It is also possible that the SMP preform 79 and projections 72 could be
compressed using air pressure to replace the pestle 82.
The preform 79 can be used as an ophthalmic mold or used to form an
ophthalmic mold of this invention. The surface 84 of the preform 79 is preferably
formed to provide optical charact sristics and/or preferably can be changed via the
intrinsic actuators 85 to provide customized optical characteristics. The preform
surface 84 could be modified by 1.eating each intrinsic actuator 85 individually to a
temperature above the SMP Tg, as needed., using a local heating source indicated by
the arrows 86 in Fig. 14. This local heating source 86 could be a CO2 laser, or an
array of micro-heating coils. The heating would occur for some period of time
referred to as the heating dwell time and then the intrinsic actuator 85 would be
allowed to cool to a temperature b slow the SMP Tg. After heating and cooling the
intrinsic actuator 85 the shape of the surface 84 in the area of the intrinsic actuator

85 that was heated would change. Heating the intrinsic actuator 85 will cause it to
recover its original shape, eith;r partially or entirely depending on the total heating
time.
The heating of the intriisic actuators 85 preferably occurs in an agile tool 90
shown in Fig. 14. The preform 79 is clamped into the agile tool 90 by clamping
means (not shown). The agile i ool 90 has an array of heaters 86 which are the
adjustment means in the agile tool. The agile tool 90 also provides a molding
surface 91 for the preform to be pressed against so that as the heated intrinsic
actuator 85 recovers its original shape it pushes against the molding surface of the
agile mold 90 thereby pushing and raising the surface 84 of the lens mold 79. By
heating one or more of the intrir sic actuators 85 accordingly, the desired lens mold
shape may be achieved. Alternatively, the: adjustment means could be a single
heater that could be moved via a computer controlled robot and positioned beneath
the intrinsic actuators to be heart d.
Figure 14 shows preform 79, that will be used as an ophthalmic mold after
removal from the agile tool 90, for which the intrinsic actuator 85' was heated by
heating source 86' and the surfacs 84 of tilts mold was thereby modified.
The intrinsic actuators and the balance of the preform or ophthalmic mold
may comprise the same shape memory polymers or different shape memory
polymers. Alternatively, the intriisic actuators may comprise a shape memory
polymer and the balance of the pr eform may comprise an alternative material that is
not a shape memory polymer that is compatible with the shape memory polymer
material.
In the agile tools which nuy be used to form the molds of the invention,
input signals to the adjustment me ms may be, and preferably are, the distortions or
aberrations of the eye for which the lens is being manufactured. Clinical wavefront

sensors, such as aberroscopes, Hartmaim-Shack devices and mirror arrays capable of
measuring these aberrations ar i commercially available. The wavefront data, or
measured aberrations, may be represented by a set of mathematical coefficients,
such as Zemike coefficients, that may be used to form the input signals that drive the
adjustment means. The adjustrient means modifies the mold to impart one or more
optical characteristics onto all or a portion of a surface of the mold to be formed
within the agile tool. The adjustment means may modify the mold directly or by
deforming the deformable portion of the molding surface of the agile tool.
Configuration of software suitable for processing and inputting the signals for
purposes of driving the adjustment means is within the skill of one ordinarily skilled
in the art.
The data obtained through the use of the wavefront sensors may be reported
in terms of Zemike coefficients. This data then is converted mathematically into an
elevation map above and below a designated mean sphere value to obtain the optical
path difference. These elevations are then used to determine the shape to be
imparted to a surface of the mold (and thai to the lens). For the manufacture of
molds, these elevations preferabiy will determine the shape of the optically critical
surfaces of the molds.
In addition to optical characteristics, the molding surface of the agile tool,
may be used to impart a geometr/ to the optically critical surface of a second mold
member, or back curve, so that th e lens formed within the mold, has a back surface
that substantially corresponds wih that of the lens wearer's cornea. Such
modifications to the back surface may require additional modifications to the front
surface via the front curve also. ' rhis function of the mold of the invention may find
its greatest utility in the manufacture of contact lenses. The corneal topographic
data for the lens wearer may be acquired using conventional topographers. The data
initially may be applied to a soft contact lens model in an unflexed state and then by
taking into account lens flexure when the lens is placed onto the wearer's eye.

For contact lenses, preierably, corneal data is used to determine the elevation
map of the lens' back surface. Mapping of the corneal elevation onto the lens
surface may be carried out by ;iny known method. For soft contact lens production,
preferably, mapping is carried out so that the error introduced by flexure of the lens
is minimizedC In this method, the corneal elevation data is applied to a soft contact
lens in the unflexed state. The elevation data is then transformed by taking into
account lens flexure. Further ihe data is manipulated for application of the data to
the optically critical surface oi a mold, preferably the back curve lens mold, so that it
will have the intended effect on the back surface of the contact lens.
In this method, for practical considerations, it is assumed that the ideal
cornea is spherical and that the: actual corneal elevations and their best spherical fit
are denoted f(x) and g(x), the function g(x) being part of a sphere having radius Ra.
In general, the radius Rb of an unflexed soft contact lens is spherical and is larger
than that of the best spherical Bt g(x). The first step is to transform the corneal
elevations f(x) into a larger sc ale for which the best spherical fit will have a radius
equal to Rb- One approach in simplifying the transformation is to represent the
function f(x) in polar coordinetes as f(0). Then using the scale factor a = Rb/Ra, the
scaled version of the corneal elevation may be expressed as :

In the second stage, ths scaled corneal elevation, f (9), is scaled down so that
the area covered by the soft contact lens corresponds to the area of the cornea. In a
two dimensional case, this scaling down is obtained according to the following
relationship:
The mapping transfon nations given in the above equations are not restricted
to the case in which the cornea and the back surface of the contact lens are spherical.

Rather, the true corneal and lens curvatures may be used to calculate the scale
parameter a as a ratio between the lens and the corneal radius of curvature. In the
general case, the scale parameter will be a function of 0, i.e., a = Rb(0)/Ra(0) =
a(6).
The mapping transformation discussed above may be generalized to the case
of three dimensional transformation. In such a case, the corneal elevations may be
represented by a function, f(θ,o) where 0 andC represent the azimuth and elevation
angle, respectively. The origiral elevation data is scaled up from the radius of
curvature Ra (θ,φ) using the following transformation relationship:

To obtain a desired bank surface of the lens, the functional f(1)(θ,φ)is scaled
back down. However, in the three dimensional case, there are a number of options
to choose from in performing the scaling operation such that the area is preserved.
For example, if it is assumed 'hat the deformation of the material is uniformly radial,
the scaling may be performed by scaling the elevation angle only, leaving the
original azimuth angle. This s expressed in the following relationship:

Once the mold is defcrmed to the desired shape, via one of the embodiments
described, the mold is then used to form the desired ophthalmic product. Therefore,
in another embodiment, the i ivention provides a process for manufacturing a mold
comprising a shape memory polymer comprising, consisting essentially of, and
consisting of the steps of: a.) providing an agile tool comprising adjustment means
b.) adjusting said adjustmenl means to impart one or more optical characteristics
onto a surface of a shape menory polymer or alloy; c.) placing a shape memory

polymer or alloy preform into said agile tool; d.) heating at least some portion of
said preform; and e.) cooling said preform.
The shape memory polymer can be introduced onto the agile tool as
described above for the press, tiat is by using a holder and an alignment jig.
The mold of this invent on is used in a process of making an ophthalmic
lens. The lens-forming material may be any material suitable for forming an
ophthalmic lens. Exemplary spectacle lens-forming materials include, without
limitation, polycarbonates, such as bisphenol A polycarbonates, allyl diglycol
carbonates, such as diethylene glycol bisallyl carbonate (CR-39™), allylic esters,
such as triallyl cyanurate, triall A phosphate and triallyl citrate, acrylic esters,
acrylates, methacrylates, such is methyl- ethyl- and butyl methacrylates and
acrylates, styrenics, polyesters, and the like and combinations thereof. Additionally,
the lens forming material may >e one or more of the phosphine oxides disclosed in
U.S. Patent No. 6,008,299 incorporated herein in its entirety by reference.
Suitable lens-forming materials for contact lenses are any materials useful
for forming hard or soft contact lenses. Preferably, the lens-forming material is
suitable for forming a soft com act lens. Illustrative materials for formation of soft
contact lenses include, without limitation silicone elastomers, silicone-containing
macromers including, without [imitation, those disclosed in United States Patent
Nos. 5,371,147, 5,314,960, and 5,057,578 incorporated in their entireties herein by
reference, hydrogels, sihcone-containiBg hydrogels, and the like and combinations
thereof. More preferably, the surface is a siloxane, or contains a siloxane
functionality, including, witho it limitation, polydimethyl siloxane macromers,
methacryloxypropyl polyalkyl siloxanes, and mixtures thereof, silicone hydrogel or
a hydrogel, such as etafilcon A.

Suitable materials for forming iatraocular lenses include, without limitation,
polymethyl methacrylate, hydroxyethyl methacrylate, inert clear plastics, silicone-
based polymers, and the like ind combinations thereof.
Curing of the lens forming material deposited within the mold may be
carried out by any means kno wn including, without limitation, thermal, irradiation,
chemical, electromagnetic raciation curing and the like and combinations thereof.
Preferably, molding is carried out using ultraviolet light or using the full spectrum of
visible light. Many shape memory polymers are transparent to ultraviolet or visible
light making them particularly well suited for use as ophthalmic molds.
More specifically, the conditions suitable for curing the lens-forming
material will depend on the m iterial selected and the lens to be formed. For
formation of spectacle lenses, a preferred curing condition is a two-stage UV cure in
which the mold assembly is exposed to low intensity and then high intensity
ultraviolet light. Low intensity UV light is UV light with an intensity of about 0.5 to
about 50, preferably about 1 tc about 5 mW/cm2. High intensity UV light is of an
intensity of about 50 to about 2000, preferably 500 to about 1500 mW/cm2. The
wavelengths at which the exposures are carried out may be, and preferably are, the
same. Suitable wavelengths are about 300 to about 450, preferably about 360 to
about 400 run. The time for the low intensity exposure will depend on the lens-
material selected, the type and amount of any initiator used, material viscosity and
the nature of its reactive groups, and the intensity of the UV light. Subsequent to the
termination of the low intensity exposure, the mold assembly is exposed to high
intensity UV light under conditions suitable to complete through-cure of the lens-
forming. The same factors determinative for low intensity exposure time are
determinative for the high inter sity exposure time. Both high and low intensity
exposure may, and preferably are, carried out as single, continuous exposures.
However, the exposures also may be carried out using alternating periods of UV
exposure and non-exposure per.ods. The low and high intensity polymerization
steps may be carried out at a temperature between about 10 to about 50° C and

atmospheric pressure, preferably at ambient temperature. The UV exposure may be
used alone or in combination with heat.
Polymerization proces ses for contact lenses are well known. Suitable
processes are disclosed in U.S. Patent No. 5,540,410 incorporated herein in its
entirety by reference. For formation of contact lenses, a preferred curing condition
is to pre-cure the mold assembly using UV light with an intensity of about 2 to about
10 mW/cm2. Following the p-e-cure, the mold assembly is exposed to UV light of
an intensity of about 0 to about 4.0 mW/cm2. Suitable wavelengths are about 300 to
about 500 nm. The time for the low intensity exposure will depend on the lens-
material selected, the type anc. amount of any initiator used, material viscosity and
the nature of its reactive groups, and the: intensity of the UV light. Both pre-cure and
subsequent UV exposure ma>, and preferably are, carried out as single, continuous
exposures. However, the expasures also may be carried out using alternating
periods of UV exposure and r on-exposure periods. The polymerization steps
preferably is carried out at a t imperative between about 40 to about 75° C and
atmospheric pressure preferably under a blanket of nitrogen gas. Total cure time is
between about 300 to about 5 DO seconds. Once the curing is completed and the
formed lens is removed from the mold. Depending on the lens material, the lens
may go through further processing prior to use. Additional process steps, such as
hydration, inspection, and packaging have been disclosed in the prior art.
The mold comprising the SMP or SMA may be re-used after it is used to
form an ophthalmic product. The SMP or SMA is just heated above it glass
transition temperature and preferably returned to its preform shape, either flattened
into a sheet and cooled or compressed in a compression fixture to return it to its non-
deformed mold shape and cooled. The SMP or SMA preform sheet can be used
again in any of the methods c f making the mold described herein. The SMP and
SMA molds can alternatively be re-shaped without returning them to their preform
shape. With care the SMP and SMA molds can be used to form multiple lenses,
although preferably they are ised once and then returned to their preform shape.

The adjustment means nay be manipulated so that the agile tool returns to its
first shape or assumes another shape for use in forming a mold of another
prescription. Alternatively, in the case that the molding surface of an agile tool is an
SMP or an SMA, all or a portion of the molding surface first may be deformed by
the adjustment means, heated lo above the molding surface material's Tg,
subsequently cooled, and then it can be re-used to form another mold.
In one embodiment of this invention, the mold of the invention may be used
to provide any ophthalmic lenses suitable to correct visual acuity defects. However,
the molds of the invention may find particular utility in providing lenses that are
formed using an agile tool tha: can be customized to correct the aberrations, both
low and high order, of a speciic lens wearer. Fig. 15 is a flow diagram of a method
for providing such lenses using the molds of the invention.
In step 401 of the method, a lens, wearer's prescription information is
determined. By "prescription information" is meant information necessary to
correct the low order aberrations of (he lens wearer. This information includes,
without limitation, sphere, cy.inder, axis, add power, and the like, and combinations
thereof. The information may be obtained using conventional ocular measuring
devices or, and preferably, by use of wavefront sensors. Optionally and preferably,
in step 402, optical data is deiermined for the lens wearer. "Optical data" means
measurement of higher order ocular aberrations. Such data is obtained using
wavefront sensors. Finally, optionaUy and preferably, patient fit data is determined
in step 403. For contact lenses, such data will include, without limitation, corneal
topographic measurements of the lens wearer's cornea.C For spectacle lenses, such
information will include, without limitation, fitting height, distance zone pupillary
distance, and the like, and combinations thereof.
The prescription infoirnation, optical data, and patient fit data (collectively,
the "order information") is tt.en sent to the lens manufacturer (404) by any

convenient ordering means including, without limitation, telephone, facsimile
transmission, internet website, and the Like and combinations thereof. In a preferred
embodiment, ordering is carried out via the lens manufacturer's internet website by
the customer using any means capable of communicating with the lens
manufacturer's server system (web server or web site). Suitable means for
communicating with the webste include, without limitation, a personal computer
and modem. Thus, in yet anotaer embodiment the invention provides a method for
producing customized ophthalmic lenses comprising, consisting essentially of, and
consisting of the steps of: a.) 'ransmitting, by a customer using a computer system,
to a lens manufacturer's serve:- system lens order information; b.) manufacturing by
the lens manufacturer at least one mold member using an agile tool comprising,
adjustment means for deformiig a molding surface (405); and c.) forming a lens
using said mold member (406).
In carrying out manufacturing of the lenses, the lens manufacture uses the
order information, in whole or in part, to drive the adjustment means of the agile tool
to manufacture a mold member and using the mold member preferably in
combination with another mo d member to manufacture the wearer's lens. By
"customer" is meant an ordercr of spectacle lenses, contact lenses, interocular lenses
or the like. Examples of lens orderers include, without limitation, ophthalmologists,
optometrists, opticians, lens r stailers, lens wearers, and the like. Preferably, the
method of the invention is earned out so that it is a business-to-business system.
One or more mold members used to form ophthalmic lenses may comprise
the shape memory polymers or shape memory alloys. Alternatively, one mold
member formed using the shsipe memory polymers or shape memory alloys of this
invention may be paired with a second mold member that has been formed using
conventional methods and m iterials, e.g. by injection molding a thermoplastic
material as disclosed and described in US Serial No. 09/305,886 filed May 5,1999,
and US Patent 5,545,366 wh ch are bolh incorporated herein by reference, or by the

use of a reusable mold formec. out of quartz or glass. In one embodiment, the mold
member comprising the shape memory polymers or shape memory alloys, preferably
a second mold member may t e formed using an agile tool that adjusts its molding
surface to account for the lens wearer's cornea's surface information. The first mold
member (to be paired with this second mold member that comprises the SMP or
SMA) may provide for a common power correction i.e. to correct for defocus errors,
that can be provided either w th a reusable mold member, or a mold member that
can be readily injection mold 3d. Therefore, the mold of this invention may comprise
a mold member comprising S MP or SMA, and another mold member that does not
comprise SMP or SMA. The mold member that does not comprise SMP or SMA
may be a reusable mold merr ber or a disposable mold member.
The following examples are provided to illustrate the scope of the present
invention. Because these exsunples are: given for illustrative purposes only, the
invention should not be deemed limited thereto. The first two examples describe the
process of making the preferred shape memory polymers.
EXAMPLE 1
A polymeric reactioi. mixture was formulated by mixing vinyl neodecanoate
(7%), divinyl benzene (1%), and styrene (90%) in random order to yield a clear
solution. Benzoyl peroxide (2%) was then added to the resulting solution (all
composition % are by weight). The resulting solution was kept cold in a refrigerator
before use. To prepare the shape memory polymer (SMP), the reaction mixture
formulated above was injeci ed by syringe into a mold fabricated with two 14" by
14" glass plates separated by Viton spacer. The two sheets of glass were held
together by clamps around Ihe edges. The Viton spacer also acts as sealant in the
mold. The sample was ther heated in an oven maintained at atmospheric pressure
and a temperature of 75°C for 24 hours. After the sample was cured for the
specified period of time, it 7vas removed from the oven and immediately transferred

to a warm water bath. The temperature of water used was about 60°C. The SMP
sheet formed was demolded under the warm water by applying a slight prying force
at the edges of the mold. The released SMP sheet was then allowed to dry and cool
down to room temperature.
At the conclusion of l his polymerization process a clear preform sheet of a
cured shape memory polymer was obtained.
EXAMPLE 2
A polymeric reaction mixture was formulated by mixing vinyl neodecanoate
(7%), divinyl benzene (1%). and styrene (60%) in random order to form a colorless
solution. Polystyrene granules (30%) were then added to the resulting solution. The
resulting mixture was then silo wed to sit at room temperature with occasional
stirring until all the polystyiene granules were dissolved to give a clear, viscous
solution. Benzoyl peroxide (2%) was, then added to the resulting solution (all
composition % are by weigit). The resulting mixture was ultrasonicated at room
temperature for 15 minutes to yield a clear solution . The resulting solution was kept
cold in a refrigerator before use. To prepare the shape memory polymer (SMP), the
reaction mixture formulated above was injected by syringe into a mold fabricated
with two 14" by 14" glass plates separated by Viton spacer. The two sheets of glass
were held together by clamps around the edges. The Viton spacer also acts as
sealant in the mold. The simple was then heated at 75°C at atmospheric pressure for
24 hours. After the samplt was cured for the specified period of time, it was
removed from the oven ami immediately transferred to a warm water bath. The
temperature of water used was about 60°C. The SMP sheet formed was demolded
under the warm water by applying a slight prying force at the edges of the mold.
The released SMP sheet was then allowed to dry and cool down to room
temperature.

At the conclusion of this polymerization process a clear preform sheet of a
cured shape memory polymer was obtained.
The following examples, ExEiraples 3 and 4 describe a process of making a
mold member comprising an SMP using a press.
EXAMPLE 3
A sheet of polynorbornene SMP having a wide thickness variation of
between 0.65 mm and 0.85 jnm was cut into discs that were accommodated in a
holding device of the type illustrated in the drawings. The SMP disc, disposed in
the holding device, was placed in an alignment jig of the type depicted in the
drawings and disposed between a base curve element and a core element of the type
shown in the drawings.
The thus formed assembly was disposed on a hot plate and a 25 lb weight
was placed atop the core element. The SMP sample was heated to a temperature
slightly in excess of its glasu transition temperature and then the pressure was
applied. It is emphasized that this temperature was in excess of the curing
temperature of the SMP pol ynorborere
The SMP disc, pressed between the core and base curve elements, was
formed into the shape of the base curve element. Thereupon, the 25 lb weight and
the hot plate were removed and the apparatus was cooled to ambient temperature
and the thus formed front curve lens mold was removed.
The aforementioned contact lens mold member forming process was
repeated four times to produce five mold members. The thus formed contact lens
mold members were analyzed to deteimine their curvature characteristics and their
surface roughness. This was accomplished by measuring curvature, i.e. radius, in

millimeters, and its deviation from form, as measured as "PV." This value, when
multiplied by 633 nanometers, yields the degree of deviation, in nanometers, of the
mold part. These measurements were made with a Mark IV GPIXP ®
interferometer. Surface smooihness, as measured by root mean square roughness, in
microns, was also measured by an interferometer, albeit a different type of
interferometer, a New View 3]) Surface ® interferometer.
In addition to these tests, the brass insert into which the SMP molds were
disposed was measured for rad .us and PV values. Obviously, these values are the
same for all five molds since the SMP molds are formed of a single base curve
element designed for a specific metal insert.
The results of these test;; and measurements are summarized in Table 1.

EXAMPLE 4
Another example, in acco rdance with that described in Example 3, was
conducted in which four female SMP contact lens mold halves were formed of the

same sheet of polynorbornene used in Example 1. However, the four molds were
fabricated using four different base curve elements. Thus each mold was formed
from a different press assemb]y.
The measured resultsC eported for this example were identical to the results
reported in Example 3 with the exception that the surface roughness of the metal
inserts was also reported, usir g the same instruments used in Example 3. However,
two additional comparisons were included in this example. The first additional
comparison was a measurement of the surface roughness of the SMP sheet from
which the SMP molds were formed, litis measurement was made in accordance
with the procedure utilized in the determination of the surface roughness of the SMP
molds and metal inserts. The second additional comparison was another surface
roughness measurement. Ho wever, this measurement compared the surface
roughness of a contact lens mold half prepared in accordance with the prior art
procedure of utilizing anon-SMP, e.g. polystyrene, sheet as the contact lens mold
material of construction.
The results of this exunple are summarized in Table 2.



The above embodiment and examples are provided to illustrate the scope and
spirit of the present invention. These embodiments and examples will make
apparent, to those skilled in the art, other embodiments and examples. Those other
embodiments and examples are within the contemplation of the present invention.
Therefore, the present invention should be limited only by the appended claims.

We Claim
1. An ophthalmic mold comprising a shape memory polymer that is a
copolymer of styrene anc a vinyl compound.
2. A mold as claimed in cairn 1 comprising a first member and a second
member.
3. A mold as claimed in claim 2 wherein said mold is prepared in a press and
said second member of said mold is formed in a shape of a base curve
element and said first nember is formed in the shape of a front curve
element.
4. A mold as claimed in claim 3 wherein said press comprises a core element
which interacts with said base curve element and said front curve
element.
5. A mold as claimed in claim 4 wherein said base curve element and said
front curve element are formed of a metal and wherein said base curve
and said front curve elements have an optical fanning surface whose root
mean square surface roughness is no more than about 20 nanometers.
6. A mold as claimed in c aim 4 wherein said core element is provided by gas
pressure.

A mold as claimed in claim 1 wherein a mold half of said shape memory
polymer mold is prepared in a press by the steps which comprise:
a) placing a preform of a shape memory polymer between a front
curve or a base cu ve element and a core element;
b) heating said preform to a temperature at or above the glass
transition tempera ture but below the decomposition temperature of
said shape memor/ polyme-;
c) providing a pressure sufficient to cause said shape memory
polymer sheet to iissume a shape of said front curve or base curve
element;
d) reducing the temperature of said formed shape memory polymer to
below said glass transition temperature; and
e) removing said formed shape memory polymer from said coining
press.
A mold as claimed in.claim 7 wherein said temperature in said step (d) is
reduced to ambient.
A mold as claimed in cla m 7 whe-ein said preform is a sheet of said shape
memory polymer being disposed in a holder prior to said step (a) and
wherein said formed shape memory polymer is removed from said holder
subsequent to said step (e).

.A mold as claimed in claim 1 comprising one or more mold members
wherein at least one mold nember is prepared in an agile tool, comprising
adjustment means that are jsed to shape said mold member.
.A mold as claimed in claim 10 wherein said adjustment means is a
plurality or an array of corcentric tubes and said agile tool comprises a
deformable molding surface
.A mold as claimed in claim 10 wherein said adjustment means is a
plurality or an array of pins.
.A mold as claimed in claim L0 wherein said adjustment means is an array
of heaters.
.A mold as claimed in claim 10 wherein said shape memory polymer halves
are prepared in said agile tool by the steps which comprise:
a) contacting a sheet of a shape memory polymer between
deformable molding surface, whose shape is defined by adjustment
means, and a core element under a pressure sufficient to cause
said shape memory polymer sheet to assume a shape of said front
curve or base curve actuated surface at a temperature at or above
the glass transition temperature but below the decomposition
temperature of said shape memory polymer;
b) reducing the temperature of said formed shape memory polymer to
below said glass trans tion temperature;

c) moving said core eement out of contact with said sheet of said
shape memory polymer; and
d) removing a contact lens mold half formed shape memory polymer
from said agile tool.
i.A mold as claimed in clain 14 wherein said sheet of said shape memory
polymer is disposed in a holder prior to said step (a) and said formed
shape memory polymer is removed from said holder subsequent to said
step (d).
. A mold as claimed in clain 2 wherein at least one surface of at least one
mold member is formed b/ gas pressure that presses the surface opposite
said one surface against a surface of a press or agile tool.
.A mold as claimed in clam 16 wherein said surface of said agile tool is
formed by a plurality of concentric tubes.
.A mold as claimed in clain 1 wherein said mold is prepared by the steps
which comprise:
a) disposing a sheet of a shape memory polymer upon an adjustment
means, set to define a predetermined shape, said adjustment
means being in a desired shape;

b) elevating the temperature of said sheet of said shape memory
polymer to at least the glass transition temperature but below the
decomposition temperature;
c) emitting a stream of gas at said sheet of said shape memory
polymer at a pressure sufficient to cause a sheet of said shape
memory polymer to form shape of said actuator means;
d) reducing the temperature cf said formed shape memory polymer to
below said glass transition temperature
e) removing said formed shape memory polymer from atop said
adjustment means.
.A mold as claimed in claim 18 wherein said reducing of temperature in
step (d) is reduced to ambient.
.A mold as claimed in cairn 18 comprising the step of creating a vacuum
concurrent with step (c.'.
.A mold as claimed in claim 1, additionally comprises intrinsic actuators.
.A mold as claimed in claim 21, wherein said mold is prepared by the steps
which comprise:
a) compressing a preform: with projections on one surface of said
preform;

b) actuating selected intrinsic ectuators by heating said individual
intrinsic actuators above the Tg of said intrinsic actuators; and
c) cooling said intrinsic members.
The mold as claimed in claim 1, wherein the vinyl compound is a
compound other than styrens.
The mold as claimed in claim 23, wherein the mold comprises a
multifunctional crosslinking cgent.
The mold as claimed in claim 24, wherein the mold comprises a modifying
polymer.
The mold as claimed in claim 25, wierein said vinyl compound is vinyl
neodecanoate, vinyl benzoate, vinyl propionate, vinyl stearate, a
methylstyrene, 4-(vinyloxy)butyl stearate or a vinyl pyridine.
The mold as claimed in claim 24, wherein the crosslinking agent is
difunctional.
The mold as claimed in claim 27, wherein the crosslinking agent is divinyl
benzene, bis(4(vinylo>y)butyl)terephthalate or bis(4-
(vinyloxy)methyl)cyclohexyl)methyl terephthalate.

.The mold as claimed in claim 25, wherein said modifying polymer is a
thermoplastic polymer compatible with said polymer formed by the
reaction product of said stvrene andsaid vinyl compound.
.The mold as claimed in daim 27, wherein said vinyl compound a vinyl
neodecanoate and said difunctional crosslinking agent is divinyl benzene.
..An ophthalmic mold comprising a shape memory polymer reaction mixture
comprising about 30 to about 95 percent styrene, about 5 to about 60
percent vinyl compound, about 0.5 to about 5 percent of a difunctional
crosslinking agent, wherein said percentages being about weight based on
the total weight of the mixture.

The invention relates to a shape memory polymer contact lens mold is formed
from a sheet of a shape memory polymer in a press, an agile tool or by an agile
tool formed by an inert gas at a temperature at or above the glass transition
temperature which is there - upon cooled to below the glass transition
temperature and removed therefrom.

Documents:

923-KOLNP-2003-FORM-27.pdf

923-kolnp-2003-granted-abstract.pdf

923-kolnp-2003-granted-claims.pdf

923-kolnp-2003-granted-correspondence.pdf

923-kolnp-2003-granted-description (complete).pdf

923-kolnp-2003-granted-drawings.pdf

923-kolnp-2003-granted-examination report.pdf

923-kolnp-2003-granted-form 1.pdf

923-kolnp-2003-granted-form 18.pdf

923-kolnp-2003-granted-form 2.pdf

923-kolnp-2003-granted-form 26.pdf

923-kolnp-2003-granted-form 3.pdf

923-kolnp-2003-granted-form 5.pdf

923-kolnp-2003-granted-reply to examination report.pdf

923-kolnp-2003-granted-specification.pdf


Patent Number 230195
Indian Patent Application Number 923/KOLNP/2003
PG Journal Number 09/2009
Publication Date 27-Feb-2009
Grant Date 25-Feb-2009
Date of Filing 18-Jul-2003
Name of Patentee JOHNSON & JOHNSON VISION CARE, INC.
Applicant Address CENTURION PARKWAY, SUITE 100, JACKSONVILLE, FL
Inventors:
# Inventor's Name Inventor's Address
1 HOFFMANN, GREGORY, J. 3521 BAY ISLAND CIRCLE, JACKSONVILLE BEACH, FL 32250
2 FOLEY, KENNETH, W. 1501 SHAKER COVE COURT, FRUIT COVE FL 32259
3 HOOD, PATRICK 6259 WASHINGTON MILL ROAD, BELLBROOK. OH 45305
4 ROONEY, THOMAS, R. 8664 REEDY BRANCH DRIVE, JACKSONVILLE, FL 32256
PCT International Classification Number B29D 11/00, 12/00
PCT International Application Number PCT/US2002/02203
PCT International Filing date 2002-01-24
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/263,986 2001-01-24 U.S.A.