Title of Invention

AN OPHTHALMIC LENS

Abstract The invention relates to an ophthalmic lens, comprising a transparent substrate (3); an electro-optical means (5) integrated with the substrate (3) to perform an optical function in response to an electrical stimulus; at least one photovoltaic cell (6) integrated with the substrate (3) to power the electro-optical means (5) in response to an incident light; and a control circuit (8) for controlling the electrical voltage produced by said photovoltaic cell (6), said control circuit (8) being integrated with the substrate (3). The photovoltaic cell is semiconductor-based and the photovoltaic cell is incorporated in an opaque component (7) integrated with the substrate and occupying an area of less than 10% of the area of the lens.
Full Text The present invention relates to an ophthalmic lens
including electro-optical means.
Numerous attempts have been made to adapt certain
optical characteristics of ophthalmic lenses, or
spectacles eyeglasses, dynamically in order to improve
comfort or in order to provide new functions for wearers
of the lenses. By way of example, the light transmission
of lenses can be reduced under conditions of high
brightness, and can be increased again when ambient light
returns to a normal or low level of intensity.
Photochromic lenses perform this function, but the
variations in light transmission provided by such lenses
are determined by the intensity of ultraviolet radiation
illuminating the lenses. The light transmission level
adopted by photochromic lenses is therefore unsuitable
under certain circumstances. In particular, photochromic
lenses inside a car remain in a state of high
transparency whenever the level of sunlight. A car driver
is therefore not protected against being dazzled when
wearing spectacles with photochromic lenses.
Electro-optical systems enable an optical
characteristic to be controlled by means oi an electrical
stimulus. By way of example, the light transmission of an
electrochromic lens varies in response to an electric
current.
Electro-optical systems thus require an electrical
power supply in order to deliver the electrical stimulus.
Small-sized batteries have been integrated with
spectacles frames so as to power electro-optical devices
integrated with the lenses. Such batteries have been
placed on the branches or "temples" of the spectacles, or
they have been hidden in the bridge of the frame between

the two lenses. Electrical connections then connect the
battery(ies) to the electro-optical system.
Such battery power supplies suffer from the
drawback of significant weight and size. In addition,
they are reserved for lenses that have been specially
produced for a frame of given shape. Unfortunately, in
most cases, lenses are produced independently of frames.
They are then cut, trimmed, and/or drilled so as to be
brought to the dimensions of a frame or a jig, and then
they are assembled to the frame or to the jig. Because of
the wide variety of shapes of frames and jigs, it is
difficult to design electrical connections that include a
portion that is made on the lens prior to the lens being
cut to size. In addition, such connections need to be
connected to the frame after the lenses have been
assembled in the frame. Making such connections is
particularly expensive since it requires finishing steps
to be performed.
An object of the present invention thus consists in
proposing an ophthalmic lens fitted with an electro-
optical system that does not present the above-mentioned
drawbacks.
The invention thus provides an ophthalmic lens
-comprising a transparent substrate and electro-optical
means integrated with the substrate to perform an optical
function in response to an electrical stimulus. The lens
of the invention further comprises at least one
photovoltaic cell integrated with the substrate to power
the electro-optical means in response to incident light,
and, optionally a control circuit for controlling the
electrical voltage produced by the photovoltaic cell,
said control circuit being integrated with the substrate.
Thus, according to the invention, both the electro-
optical system and the electrical power supply are
integrated with the substrate of the lens. The electrical

connections between the electro-optical system and the
power supply can thus also be integrated with the lens
substrate, so these connections are separate from the
frame. They can be implemented within the lens before it
is assembled to the frame. The assembly that is performed
subsequently does not need to be modified by the presence
of the electro-optical system. In particular, it can be
performed at low cost.
Furthermore, integrating the electrical connections
in the substrate of the lens makes it possible to use
connections of small dimensions, or indeed miniature
connections. Such connections can be discreet or even
invisible. They are therefore compatible with the
appearance requirements applicable to the field of
spectacles.
Another advantage of a spectacles lens according to
the invention comes from the nature of the electrical
power supply used. Unlike a battery, a photovoltaic cell
does not need to be renewed periodically, since the
energy delivered by such a cell is generated from the
incident light.
In a preferred embodiment of the invention, the
photovoltaic cell is sensitive to visible light. Thus,
the optical function is activated as a function of the
conditions of luminosity to which the eyes of the wearer
of the lenses are sensitive. The optical means are thus
activated in compliance with a visually perceived optical
function.
The photovoltaic cell may be integrated with the
lens substrate in various ways. In a first type of
embodiment, the photovoltaic cell is incorporated in an
opaque component integrated with the substrate and
occupying less than 10% of the area of the lens. This
leads to very little or even no visual impediment, given
the very small size of the opaque component, which makes

it possible to maintain the transparency of the lens
intact over that part of the lens surface that is used
for vision purposes.
In a second type of embodiment, the photovoltaic
cell is partially transparent and presents a light-
collecting surface that covers at least part of the
surface of the lens. Under such circumstances, the light-
collecting surface can be large, thereby enabling an
increased electrical stimulus to be obtained. In
addition, embodiments of this type do not necessarily use
an opaque component, which means that lens configurations
can be obtained that are particularly attractive in
appearance.
The control circuit is also advantageously
integrated with the lens substrate. It can enable the
electrical stimulus delivered to the electro-optical
means to be adapted relative to an amplitude desired for
the optical function. It also makes it possible to adapt
the electrical stimulus relative to intrinsic operating
characteristics of the electro-optical means. In
particular, the control circuit may include a step-up
circuit for raising the electrical voltage produced by
the photovoltaic cell, in particular for the purpose of
reaching an activation threshold for the optical
function.
Optionally, the control circuit may be partially
transparent. Under such circumstances, it may be located
at least in part in a portion of the lens that is used
for vision purposes. The term "a portion of the lens that
is used for vision purposes" is used to mean a portion of
the lens that is located between the eye and an object
being looked at in the field of view. Then there is no
appearance impediment as a result of the presence of the
control circuit within the lens.

Optionally, the use of a control circuit can be
avoided by connecting several photovoltaic elements in
series so as to obtain an appropriate power supply
voltage.
The invention also provides a vision device, in
particular a pair of spectacles, including at least one
ophthalmic lens as described above.
Other features and advantages of the present
invention will appear from the following description of
two non-limiting embodiments, given with reference to the
accompanying drawings, in which :
• Figure la shows a pair of spectacles in a first
embodiment of the invention ;
Figure lb is a section through a lens in the
embodiment of Figure la ;
Figure 2a shows a spectacles lens in a second
embodiment of the invention ; and
Figure 2b is a section through a lens in the
embodiment of Figure 2a.
In the figures, and for reasons of clarity, the
dimensions of the various elements shown are not
proportional to their real dimensions. Furthermore, throughout the figures, identical references correspond
to elements that are identical or that have identical
functions.
The optical function of the lens may be of various
types. It may be a function of reinforcing contrast by
adapting the tint of the lens, e.g. as described in US
patent No. 6 250 759. It may be also be a function of
reinforcing contrast by filtering light with a determined
direction of polarization.
In the embodiments described below by way of
example, the optical function of the lens is a function
of providing protection against the sun, or protection

against being dazzled. This function is activated
electrically. In an initial state, each lens in a pair of
spectacles presents high light transmission in the
visible spectrum. In response to an electrical stimulus,
the lens becomes darker : its light transmission is
reduced in the visible spectrum.
To do this, the electro-optical means comprise a
system having a variable light transmission. Such system
may be of the electrochromic type, for example. In a
preferred manner, it is a system with little electricity
consumption, such as a system based on liquid crystals or
a system of electrophoretic type. For such systems, the
electrical stimulus that leads to a variation in light
transmission is an electric field, i.e. it corresponds to
an electrical voltage being applied across two input
terminals of the system. Electricity consumption is low,
and is compatible with an electrical power supply of
small dimensions.
In a first embodiment, shown in Figures la and lb,
the photovoltaic cell is semiconductor-based. Such a
photovoltaic cell can be made using any known technology,
e.g. by using one of the following alloys : cadmium
telluride (CdTe), gallium arsenide (GaAs), or a
chalcopyrite containing copper such as copper and indium
disclenide (CIS) . Advantageously, the photovoltaic cell
is based on single crystal silicon, or is based on
microcrystalline or amorphous silicon.
Its cost is then low, and it does not contain any
material presenting a risk of toxicity in the event of
the lens being broken or damaged. Photovoltaic cells
implemented using the above-listed technologies all
present a spectral response that includes at least a
portion of the spectrum that is visible to the human eye.
As shown in Figure la, a pair of spectacles is
constituted by a frame 1 having two temples 2, and two

ophthalmic lenses 3 assembled in the frame 1. The term
"ophthalmic lens" is used to mean any lens comprising a
transparent substrate of inorganic and/or organic
material, of composition and of shape that can be varied
to fit a spectacles frame so as to protect and/or correct
eyesight. The lenses may be afocal, unifocal, bifocal,
trifocal, or progressive. In particular, an ophthalmic
lens may present a structure comprising multiple layers
and/or a laminated structure. Fabrication may then
include operations of depositing layers on the substrate,
e.g. by evaporating determined materials. Fabrication may
also include operations of assembling a plurality of
substrates together, i.e. " substrate units", in order to
form the final substrate of each lens 3. Substrate units
are assembled to one another by lamination or by
adhesive, for example.
Each lens 3 incorporates a variable transmission
system 5, e.g. a liquid crystal system. Such a liquid
crystal system may be of the type having a holding
voltage or it may be of the bistable type. A holding
voltage system is controlled by an electrical voltage of
about 3 volts, whereas a bistable system requires an
electrical voltage pulse of 15 volts in order to cause
optical switching to occur. The system 5 may be disposed over a fraction of the surface of the lens 3 that is used
for vision purposes. It may also be disposed over the
entire area of the lens.
Each lens 3 also incorporates a photovoltaic cell
6, e.g. of the single-crystal silicon type, of
microcrystalline silicon type or of amorphous silicon
type. The photovoltaic cell 6 may be incorporated in an
opaque component 7 integrated with the substrate of the
lens and occupying an area that is significantly smaller
than the area of the lens. Preferably, the opaque
component 7 occupies an area of less than 10% of the area
of the lens. The dimensions of the opaque component 7 may

be 2 millimeters (mm) by 3 mm, for example. Such an
opaque component 7 is located in a portion of each lens 3
that is not used for vision purposes, for example in a
bottom side portion of the lens.
An electronic control circuit 8 (Figure lb) may
also be incorporated in each opaque component 7. Each
control circuit 8 may comprise an adapter of the
electrical voltage delivered by the photovoltaic cell 6
with which it is associated in a single component 7. The
connection between the control circuit 8 and the
photovoltaic cell 6 is also incorporated in the component
7. It can be made by using any of the known techniques
for assembling integrated electronic circuits.
As shown in Figure lb, each of the lenses 3 may be
constituted by two transparent substrate units 3a and 3b
assembled together by adhesive in the proximity of their
periphery. The substrate unit 3a is the back substrate
and the substrate unit 3b is the front substrate. Each of
the substrates 3a and 3b presents high light transmission
in the visible spectrum, e.g. 97%.
The liquid crystal system 5 is interposed between
the two substrates 3a and 3b in the form of a film.
Preferably, the surface inside the lens of one of the substrates 3a or 3b presents a housing that is
complementary in shape to the shape of the liquid crystal
system 5. By providing such a housing, the operation of
the liquid crystal system 5 is not disturbed by any
stresses that might otherwise result from assembling the
substrates 3a and 3b together.
The substrate unit 3b presents a housing 10 in its
face that is on the inside of the lens. The housing 10
may be made when molding the substrate 3b, or it may be
made by machining after the substrate 3b has been molded.
The component 7 which incorporates the photovoltaic cell
6 and the control circuit 8 may be bonded adhesively in

the housing 10. Two electrical connections 9a and 9b,
secured to the component 7 and coming from the control
circuit 8, each have a shape of contact point. When the
two substrates 3a and 3b are assembled together via their
respective surfaces that are inside the lens, the two
connections 9a and 9b come into contact with the
respective electrical power supply terminals of the
liquid crystal system 5 which are placed so as to face
the connections 9a and 9b during the assembly operation.
Although Figures la and lb show only one
photovoltaic cell arranged within each lens, a plurality
of photovoltaic cells may be distributed over the surface
of each lens. Under such circumstances, appropriate
connections interconnect the photovoltaic cells within a
given lens so as to obtain, in known manner, an
electrical power supply that presents current and voltage
characteristics adapted to the operation features of the
liquid crystal system 5.
A larger number of photovoltaic cells of very small
dimensions can also be integrated with each lens, with
each cell occupying an area of the lens that is less than
100 square-micrometers, for example. Each photovoltaic
cell then constitutes a spot that is individually
invisible, and the lens remains overall transparent because of the gaps between neighbouring photoVoltaic
cells over the surface of the lens.
In a second embodiment as described below, the
photovoltaic cell 6 is partially transparent. It
possesses a light-collecting area that covers at least a
portion of the area of each lens. Thus, as shown in
Figures 2a and 2b, the portion of the area of the lens 3
that is occupied by the photovoltaic cell 6 may be of the
same order as the portion of the area of the lens 3 that
is occupied by the liquid crystal system 5.

Preferably, the light fraction absorbed by the
photovoltaic cell 6 at any point thereof is less than 30%
of the light incident on the lens 3 at that point. Thus,
the presence of the photovoltaic cell 6 in a portion of
the surface of the lens 3 that is useful for vision
purposes is nevertheless compatible with the lens 3
presenting high light transmission so long as its solar
protection function is not activated.
The photovoltaic cell 6 may be of the photo-
electrochemical type. It then comprises two transparent
planar electrodes 6a and 6b (Figure 2b) arranged so as to
face each other parallel to the surface of the lens 3.
The final substrate of the lens 3 is then made up of
three substrate units 3a, 3b, and 3c that are assembled
together in such a manner that the substrate unit 3c is
located between the substrate units 3a and 3b. The
electrodes 6a and 6b are arranged on the inner faces of
the substrate units 3a and 3b that are facing each other.
The electrodes 6a and 6b are spaced apart from each other
by a distance of about 0.05 millimeters, and they are not
in direct electrical contact with each other. At least
one of the electrodes 6a or 6b may be based on indium and
tin oxide (ITO) or on fluorine-doped tin oxide (SnO2,F).
They are separated by a cavity 6c that is filled with an electrelyte. The electrolyte could be liquid, but it is
preferably solid. The electrolyte may also be replaced by
an organic or an inorganic material having p-type
conductive properties, i.e. constituted by a hole
conductor.
The photo-electrochemical cell incorporates
elements that are capable of absorbing a fraction of the
light passing through the lens 3. By way of example,
these elements may be nanocrystals or fullerenes. When
the photo-electrochemical cell contains nanocrystals of
metallic oxides, it may be of the type described in the
article "A low-cost, high-efficiency solar cell based on

dye-sensitized colloidal TiO2 films" by Brian O'Regan and
Michael Graetzel, Nature 353 (1991), pp. 737-740. Under
such circumstances, the nanocrystals are based on
titanium oxide (TiO2) and have molecules of a dye grafted
to their surfaces. Reference can be made to the above-
mentioned article for further details on such a
photovoltaic cell and methods of making it.
The liquid crystal system 5 is placed between the
substrates 3a and 3c. Two connections 9a and 9b connect
the photovoltaic cell 6 to the liquid crystal system 5.
The connection 9a connects the electrode 6a to one of the
power supply terminals of the liquid crystal system 5,
and the connection 9b connects the electrode 6b to the
other power supply terminal of the system 5. Each of the
connections 9a and 9b may have a configuration and a
method of assembly of the same kind as described above
with reference to Figure lb.
Figures 2a and 2b do not show a circuit for
controlling the voltage supplied by the photovoltaic cell
6 to the liquid crystal system 5. Such a control circuit
may be incorporated in the lens 3 of Figures 2a and 2b
within an opaque component analogous to that described
with reference to Figures la and lb. Preferably, in the
second embodiment described, the control circuit is implemented in a form that is directly integrated with
one of the substrate units of the lens 3. In known
manner, the control circuit may then also be transparent.
It can be located in any portion of the surface of the
lens 3 without reducing the field of view and without
impeding the wearer of the spectacles.
In all embodiments of the invention, each lens may
further comprise means for interrupting the supply of
power from the photovoltaic cell to the electro-optical
means. Such control means may comprise a switch that is
connected in suitable manner. In particular, such a
switch may be disposed on one of the connections

connecting the photovoltaic cell to the electro-optical
means. It then makes it possible to open the electrical
circuit which powers the electro-optical means, so as to
interrupt the supply of power thereto. The switch may
also be connected between the power supply inputs of the
electro-optical means. Short circuiting the power supply
terminals of the electro-optical means then causes the
optical function to be switched off. Such a switch can be
controlled manually. It may be a miniature switch placed
flush with the anterior surface of the lens. In
particular, it may be a switch incorporated in an opaque
component as described above.
Each lens may also include a photodiode or a
phototransistor suitably connected to set intensity
thresholds of incident light and particular modes of
activating or deactivating the optical function. Such a
photosensitive electronic component may also be
incorporated in the opaque component. In a variant, it
may be partially transparent and integrated directly in
one of the substrate units of the lens.
Finally, it should be understood that the invention
presented above in the context of an application to
spectacles lenses may also be applied to any other vision
device. Specifically, such vision devices may comprise a
helmet for a driver or a motorcyclist, or goggles for
climbing or skiing. The photovoltaic cell and the
electro-optical system are then integrated with the visor
of the helmet or in the lens(es) of the goggles.

WE CLAIM:
1. An ophthalmic lens, comprising a transparent substrate (3); an electro-
optical means (5) integrated with the substrate (3) to perform an
optical function in response to an electrical stimulus; at least one
photovoltaic cell (6) integrated with the substrate (3) to power the
electro-optical means (5) in response to an incident light; and a control
circuit (8) for controlling the electrical voltage produced by said
photovoltaic cell (6), said control circuit (8) being integrated with the
substrate (3), characterized in that the photovoltaic cell is
semiconductor-based and the photovoltaic cell is incorporated in an
opaque component (7) integrated with the substrate and occupying an
area of less than 10% of the area of the lens.
2. The ophthalmic lens as claimed in claim 1, wherein the photovoltaic cell
is based on single crystal, or is based on microcrystalline or
amorphous silicon.
3. The ophthalmic lens as claimed in claim 1, wherein the photovoltaic cell
is based on cadmium telluride, or is based on a chalcopyrite containing
copper.
4. The ophthalmic lens as claimed in claim 1, wherein several photovoltaic
cells are distributed in series over the area of the lens.

5. The ophthalmic lens as claimed in claim 1, wherein several photovoltaic
cells are distributed over the area of the lens at least one electrical voltage
control circuit is integrated with the substrate.
6. The ophthalmic lens as claimed in claim 1, wherein the photovoltaic cell is
partially transparent and possesses a light-collecting surface that covers at
least a portion of the surface of the lens.
7. The ophthalmic lens as claimed in claim 1, wherein the electro-optical
means comprise a variable light transmission system.
8. The ophthalmic lens as claimed in claim 7, wherein the variable light
transmission system is based on liquid crystals.
9. The ophthalmic lens as claimed in claim 7, wherein the variable light
transmission system is of electrophoretic type.
10. The ophthalmic lens as claimed in claim 1, wherein the control circuit (8)
is partially transparent.
11. The ophthalmic lens as claimed in claim 1, wherein the control circuit
comprises a step-up circuit (8) for raising the electrical voltage
produced by the photovoltaic cell (6).

12. The ophthalmic lens as claimed in claim 1, comprising control means for
interrupting the power supplied by the photovoltaic cell (6) to the electro-
optical means (5).
13. A vision device comprising at least one ophthalmic spectacle lens as
claimed in claim 1, and a pair of spectacles.


ABSTRACT

AN OPHTHALMIC LENS
The invention relates to an ophthalmic lens, comprising a transparent
substrate (3); an electro-optical means (5) integrated with the substrate
(3) to perform an optical function in response to an electrical stimulus; at
least one photovoltaic cell (6) integrated with the substrate (3) to power
the electro-optical means (5) in response to an incident light; and a
control circuit (8) for controlling the electrical voltage produced by said
photovoltaic cell (6), said control circuit (8) being integrated with the
substrate (3). The photovoltaic cell is semiconductor-based and the
photovoltaic cell is incorporated in an opaque component (7) integrated
with the substrate and occupying an area of less than 10% of the area of
the lens.

Documents:

03498-kolnp-2006-abstract-1.1.pdf

03498-kolnp-2006-abstract.pdf

03498-kolnp-2006-claims-1.1.pdf

03498-kolnp-2006-claims.pdf

03498-kolnp-2006-correspondence others-1.1.pdf

03498-kolnp-2006-correspondence others.pdf

03498-kolnp-2006-correspondence-1.2.pdf

03498-kolnp-2006-description(complete).pdf

03498-kolnp-2006-drawings.pdf

03498-kolnp-2006-form-1.pdf

03498-kolnp-2006-form-18.pdf

03498-kolnp-2006-form-2.pdf

03498-kolnp-2006-form-26.pdf

03498-kolnp-2006-form-3.pdf

03498-kolnp-2006-form-5.pdf

03498-kolnp-2006-international publication.pdf

03498-kolnp-2006-international search authority report.pdf

03498-kolnp-2006-priority document-1.1.pdf

03498-kolnp-2006-priority document.pdf

3498-KOLNP-2006-(10-07-2012)-CORRESPONDENCE.pdf

3498-KOLNP-2006-(20-12-2011)-CLAIMS.pdf

3498-KOLNP-2006-(20-12-2011)-CORRESPONDENCE.pdf

3498-KOLNP-2006-(20-12-2011)-DESCRIPTION (COMPLETE).pdf

3498-KOLNP-2006-(20-12-2011)-EXAMINATION REPORT REPLY RECEIVED.pdf

3498-KOLNP-2006-(20-12-2011)-FORM-1.pdf

3498-KOLNP-2006-(20-12-2011)-FORM-2.pdf

3498-KOLNP-2006-(20-12-2011)-FORM-3.pdf

3498-KOLNP-2006-(20-12-2011)-FORM-5.pdf

3498-KOLNP-2006-(20-12-2011)-OTHER PATENT DOCUMENT.pdf

3498-KOLNP-2006-(20-12-2011)-OTHERS.pdf

3498-KOLNP-2006-CORRESPONDENCE 1.2.pdf

3498-KOLNP-2006-CORRESPONDENCE.1.1.pdf

3498-KOLNP-2006-EXAMINATION REPORT.pdf

3498-KOLNP-2006-FORM 18.pdf

3498-KOLNP-2006-FORM 26.pdf

3498-KOLNP-2006-FORM 3.pdf

3498-KOLNP-2006-FORM 5.pdf

3498-KOLNP-2006-GRANTED-ABSTRACT.pdf

3498-KOLNP-2006-GRANTED-CLAIMS.pdf

3498-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

3498-KOLNP-2006-GRANTED-DRAWINGS.pdf

3498-KOLNP-2006-GRANTED-FORM 1.pdf

3498-KOLNP-2006-GRANTED-FORM 2.pdf

3498-KOLNP-2006-GRANTED-SPECIFICATION.pdf

3498-KOLNP-2006-OTHERS.pdf

3498-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

abstract-03498-kolnp-2006.jpg


Patent Number 253539
Indian Patent Application Number 3498/KOLNP/2006
PG Journal Number 31/2012
Publication Date 03-Aug-2012
Grant Date 30-Jul-2012
Date of Filing 23-Nov-2006
Name of Patentee ESSILOR INTERNATIONAL (COMPAGNIE GENERALE D'OPTIQUE)
Applicant Address 147 RUE DE PARIS 94220 CHARENTON LE PONT, FRANCE
Inventors:
# Inventor's Name Inventor's Address
1 CHAPUT Frederic c/o Essilor International 147 Rue de paris 94220 Charenton-le-pont
2 CANO Jean-Paul c/o Essilor International 147 Rue de paris 94220 Charenton-le-pont
3 MEYER Andreas,F Chemin de la Bossenaz CH-1173 Fechy/VD
4 MEYER Toby,B Chemin de la Bossenaz CH-1173 Fechy/VD
PCT International Classification Number G02C7/10; G02F1/133
PCT International Application Number PCT/FR2005/001396
PCT International Filing date 2005-06-07
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 0406371 2004-06-11 France