Title of Invention

"A PANORAMIC VIEWING DEVICE"

Abstract

This invention relates to a panoramic viewing device for sighting and aiming on a target during day time, capable of operating in wide angle mode and narrow angle mode and comprising a stabilized top mirror (10), sighting head assembly (7) and a sighting tube assembly (8) having an optical path there between characterized by; said sighting head assembly (7) comprising a Galilean lens assembly (11), a dichroic prism assembly (12), an OG assembly (13), a de-rotating prism assembly (14), Turret indicator graticule assembly (18), ballistic graticule assembly (19) and a folding prism assembly (15) housed inside the said stabilised sight head assembly (7) and having optical path there between; the sighting tube assembly (8) comprising a relay lens assembly (16) connected to a eyepiece assembly (17) housed in the said sighting tube assembly and having optical path there between.

Full Text

FIELD OF INVENTION The present invention relates to a panoramic viewing device and relates particularly to a panoramic viewing device mounted on a military vehicle. PRIOR ART Military vehicles are fitted with the panoramic sights for surveillance, target acquisition and engagement purpose. The vehicle requires a highly efficient system with stabilised line of sight for this purpose. The panoramic sight operates in two modes i.e. search mode and recognition mode also known as wide field of view mode and narrow field of view mode respectively. Initially, the operator of the sight operates the panoramic device in wide angle mode to search for any target. It is always desirable to have as large field of view as possible, in this mode, so that the operator does not miss any object. Once the target is acquired, the operator switches over to the high magnification mode corresponding to narrow field of view mode. This mode is utilised to identify the target so that the crew member can take appropriate action. In any aiming device the switchover to high magnification is achieved, either by linear movement of a lens assembly or by flipping out a Galilean type of optical assembly. While switching over to the high magnification mode, it is always desirable that there should be neither any defocusing or nor shift in the position of the viewing eye. The distance between the center of the top stabilised mirror and eye position is decided by the mounting factors inside the vehicle. There are many panoramic viewing devices known in the art. Schematic diagram of one such panoramic viewing and aiming device, known in the art, has been shown in Fig l(a). This basically comprises of stabilised top mirror assembly (1), de-rotating dove prism assembly (2) , OG assembly (3), folding prism assembly (4), magnification change-over lens assembly (5) and eyepiece lens assembly (6). The stabilised top mirror is housed in the stabilised head assembly along with gyros, elevation resolvers and elevation torquers. Top mirror (1) is of glass material and is coated to maximise the reflection in visible region. The stabilised head assembly consists of two axes gyros, electrically connected in such a way so as to artificially generate a line of sight axis. The resolver is chosen keeping in view the required level of slave performance. Torquer is chosen keeping in view the requirement of the acceleration. The device further comprises a slip-ring housing consisting of a slip ring and the brush assembly. The slip ring is required to have n x 360 degree movement in azimuth axis. Various signals and power supplies are transmitted between stab head and the system electronic unit using these rings and brushes. Magnification change-over assembly (5) is basically a lens assembly which is moved linearly to achieve magnification change-over. The de-rotating prism assembly (2) consists of a de-rotating dove prism to offset the rotation of the top mirror. It is mechanically linked with the top mirror (1) and rotates by half the angle traveled by the top mirror and in the same direction. Eyepiece lens assembly (6) comprises eyepiece lenses which are used to view the target. The folding prism assembly (4) consists of a folding prism used to fold the optical path towards the eyepiece. OG assembly (2) consists of a group of lenses working as main objective of the viewing a system However, this panoramic viewing device, known in the art, suffers from the following drawbacks. The major disadvantage of the above known panoramic viewing device is that the available field of view in wide angle mode is only 18 degree because of the large distance between top stabilised mirror and the OG lens assembly. In general, it is always desirable to have as small distance between OG assembly and top mirror to maximise the available field of view for any particular size of top mirror and OG lenses. Another disadvantage of the above known panoramic viewing device is that there is shift in the focusing during magnification change-over from wide angle mode to narrow angle mode. This is due to the reason that in this viewing device, the magnification change-over is achieved by linear movement of the magnification changeover lens assembly. In such cases, where magnification change-over is achieved by linear movement of a group of lenses, defocusing is inherent. Yet another disadvantage of the above known panoramic viewing device is that the position of the eye is shifted during magnification changeover. This is again inherent when magnification change-over is achieved by linear movement of a group of lenses. Still another disadvantage of the above mentioned panoramic viewing device is that it lacks the provisioning of ballistic graticule through which firing could be done. This is because of the reason that a part of the de-rotating dove prism goes inside the slip ring assembly and as such, the provisioning of graticule lens assembly could not be made before the de-rotating dove prism. Yet another disadvantage of the above mentioned panoramic viewing device is that it lacks the provisioning of turret indicator through which the crew can know the position of the sight with respect to any fixed axis or gun axis. There are other panoramic viewing devices known in the art which overcomes some of the disadvantages of the above mentioned device. However, the maximum available field of view in wide angle mode, in all such known devices, is not greater than 18 degree. So there is a need for a panoramic viewing and aiming device with turret indicator graticule as well as ballistic graticule covering higher field of view in search mode with no defocusing as well as shift in eye position during magnification change-over. OBJECTS OF THE INVENTION Primary object of the invention is to provide a panoramic viewing device which can provide a higher field of view of 30 degree in wide angle mode thereby reducing the probability of observer missing any target during the search mode. Yet another object of the invention is to provide a panoramic viewing device having smaller distance between stabilised top mirror and OG assembly resulting in higher field of view for smaller size of the stabilised mirror. Still further object of the invention is to provide a panoramic viewing device in which the size of the top mirror is kept to minimum thus reducing the problems associated with the stabilisation of bulky top mirrors. Yet another object of the invention is to provide a panoramic viewing device which utilises a smaller pechan prism as do-rotating prism instead of bulky dove prism thereby reducing the distance between top stabilised mirror and OG assembly. Still another object of the invention is to provide a panoramic viewing device which has a turret indicator graticule assembly through which the operator can known the position of the sight with respect to any fixed axis of the vehicle. Still further object of the invention is to provide a panoramic viewing device which has a ballistic graticule assembly through which the operator can aim at any target. Yet another object of the invention is to provide a panoramic viewing device which utilises a Galilean lens assembly which is flipped out during magnification change over to the narrow angle mode corresponding to high magnification mode thereby avoiding defocusing as well as shift in the position of the eye during magnification change-over. Still another object of the invention is to provide a panoramic viewing device which utilises lenses of smaller size. SUMMARY OF THE INVENTION According to this invention there is provided a panoramic viewing device for sighting and aiming on a target during day time, operating in wide angle mode and narrow angle mode and comprising: (a) a stabilized top mirror (10), sighting head assembly (7) and a sighting tube assembly (8) having an optical path there between characterized in that, (b) said sighting head assembly (7) comprising a flalilean lens assembly (11), a dichroic prism assembly (12), an OG assembly (13), a He-rotating prism assembly (14), turret indicator graticule assembly (18), ballistic graticule assembly (19) and a folding prism assembly (15) optical path there between; (c) the sighting tube assembly (8) comprising a relay lens assembly (16) connected to a eyepiece assembly (17) having optical path there between. In accordance with this invention there is provided a panoramic viewing device mounted on a moving vehicle preferably on a military vehicle capable of operating in wide angle mode and narrow angle mode corresponding to low magnification and high magnification mode respectively. The viewing device has the capability to aim at any target during day time. The device provides a higher field of view of 30 degree corresponding to 2X magnification in wide angle mode and 7.5 degree corresponding to 8x magnification in narrow angle mode. The device is able to provide higher field of view of 30 degree with minimum possible size of top stabilised mirror and optical packaging used therein. According to the invention the panoramic viewing device.. comprises a stabilised top mirror, sighting head assembly and a corresponding sight tube assembly all interconnected so as to have optical path there between. The stabilised sighting head assembly further comprises Galilean lens assembly, dichroic prism assembly, turret indicator graticule assembly, ballistic graticule assembly, OG lens assembly, de-rotating pechan prism assembly, and folding prism assembly . The sight tube comprises erecting lens assembly and eyepiece lens assembly. The Galilean assembly can be mechanically flipped out for switching over to high magnification mode of operation. The turret indicator graticule assembly provides the information about the position of sight axis with respect of the axis of the vehicle and ballistic graticule assembly helps in aiming at the target in high magnification mode. The device is capable of operating in both the modes most efficiently without necessitating any change in the position of the eye of the operator during magnification changeover. The device is capable of providing higher field of view because of reduced distance between the top stabilised mirror and the OG lens assembly working as main objective of the device. This could be possible as a small pechan prism has been used as de-rotating prism in the device instead of lenghty dove prism. Any further characteristics, advantages and applications of the invention will become evident from the detailed description of the preferred embodiment which has been described and illustrated with the help of following drawings wherein, DESCRIPTION OF THE ACCOMANYING DRAWINGS. Fig. l(a) describes schematic diagram of a panoramic viewing device known in the art. Fig. (1) describes the schematic diagram of panoramic viewing device of present invention Fig. (2) describes the perspective view of the panoramic viewing device of the present invention. Fig. (3) describes another perspective view of panoramic viewing device of present invention Fig (4) describes schematic diagram of the complete panoramic viewing device of present invention DESCRIPTION OF THE INVENTION WITH RESPECT TO THE DRAWINGS Referring to Fig. 1, the panoramic viewing device of present invention, mainly, comprises of sighting head assembly (7), sighting tube assembly (8) and top stabilised mirror (10). The line of sight of the device has been shown by (9). The top mirror can rotate by n x 360 degree. The top mirror (10), sighting head assembly (7) and sighting tube (8) all are arranged to have optical path there between Referring to Fig. 2, the sighting head assembly (7) further comprises Galilean lens assembly (11), dichroic prism assembly (12), OG lens assembly (13), de-rotating prism assembly (14) and folding prism assembly (15). The sighting tube assembly (8) further comprises relay lens assembly (16) and eyepiece lens assembly (17). The Galilean lens assembly (11) works as a magnification change-over assembly. Initially, in wide angle mode, Galilean lens is present in the optical path, and it helps in achieving 30 degree field of view in wide angle mode corresponding to low magnification of 2X. The Galilean lens assembly (11) is flipped out from the optical path when the operation of the device is switched to narrow angle mode (7.5 degree field of view) corresponding to high magnification mode. The de-rotaing prism assembly (14) is mechanically linked with the top mirror (10). It is used to offset the effect produced by the rotation of top mirror (10) and it rotates by half the speed of the top mirror. The folding prism assembly (15) comprises a small penta prism to fold the line of sight towards the operator. The relay lens assembly (16) is used to increase the elbow length. The eyepiece lens assembly (17) is utilised to view the target in wide angle as well as narrow angle mode. Referring to Fig. 3, (18) and (19) show the turret indicator graticule assembly and ballistic graticule assembly. The turret indicator graticule (18) provides the position of line of sight of the device with respect to the axis of the vehicle and ballistic graticule (19) is used for aiming purpose Referring to Fig. 4, the Galilean lens assembly comprises of lens (20), (21), (22)& (23) wherein lens (21) and (23) are doublet lenses. Initially, in the search mode, it is present in the optical path of the viewing device helping in providing 30 degree field of view. However, it is flipped out from the optical path during magnification changeover to the high magnification mode. The turret indicator graticule assembly (18) comprises graticule pattern (25), lens (26) and lens (27). Ballistic graticule assembly (19) comprises graticule pattern (28), lens (29), prism (30) and lens (31). Both of these graticule work in conjugation with prism with dichroic coating (24) which reflects both the patterns through the prism with dichroic coating (24) towards the operators eye. The de-rotating prism assembly (14 ) comprises a small pechan prism (33) which is mechanically linked to the top stabilised mirror (10). The folding prism assembly (15) comprises a small penta prism (35) which folds the optical path towards the eye of the observer. Field lens (34) converges the light rays towards the folding penta prism (35) thus helping in keeping the size of this prism to a small value. The relay lens assembly (16) comprises a group of lenses (36), (37),(38) and (39) and this lens assembly suitably increases the elbow length of the device. The position of the operator inside the vehicle decides the elbow length of the device. The image of the object and graticule pattern is superimposed onto the fixed eyepiece graticule (40). The eyepiece lens assembly (17) comprises lenses (41), (42), (43), (44) and (45). The operator views through the eyepiece assembly (17). The operator can also know the position of the lens of sight with respect to the axis of the vehicle through turret indicator graticule (25) and can also aim at the target through ballistic graticule (28). The embodiment of the invention, which has been set forth above, was for the purpose of illustration only and it is not intended to limit the scope of the invention. It is to be understood that various changes and modifications may be made in the invention described above by those skilled in the art without departing from the scope of the invention which has been defined by the following claims. I Claims: 1. A panoramic viewing device for sighting and aiming on a target *during day time, perating in wide angle mode and narrow angle mode and comprising: (a) a stabilized top mirror (10), sighting head assembly (7) and a sighting tube assembly (8) having an optical path there between characterized (b) said sighting head assembly (7) comprising a alilean lens assembly (11), a dichroic prism assembly (12), an OG assembly (13), a de-rotating prism assembly (14), urret indicator graticule assembly (18), ballistic graticule assembly (19) and a folding prism , assembly optical path there between; (c) the sighting tube assembly (8) comprising a relay lens assembly (16) connected to a eyepiece assembly (17) and having optical path there between. 2. A panoramic viewing device as claimed in claim 1 wherein said Galilean lens assembly (11) is flipped out of the optical path by mechanical means during magnification changeover from wide angle mode to narrow angle mode. 3. A panoramic viewing device as claimed in claim 1 wherein said turret indicator graticule assembly (18) comprises graticule pattern (25), lens (26) and lens (27) all arranged with the, dichroic and having optical path there between. 4. A panoramic viewing device as claimed in claim 1 wherein the Ballistic graticule assembly (19) comprises graticule pattern (28), lens (29), prism (30) and lens (31) arranged with the said dichroic coating having optical path there between. 5. A panoramic viewing device as claimed in claim 1 wherein said de- rotating prism assembly (14) comprises a pechan prism (33) and the said folding prism assembly (15) comprises a penta prism (35) having optical path there between. 6. A panoramic viewing device as claimed in claim 1 wherein said sighting head assembly (7) comprises a field lens (34) disposed between the said pechan prism (33) and the said penta prism (35). 7. A panoramic viewing device as claimed in claim 1 wherein said relay lens assembly (16) comprises lenses (36), (37), (38) and (39) having optical path there between. 8. A panoramic viewing device as claimed in claim 1 wherein said eyepiece assembly (17) comprises lenses (41), (42), (43), (44) and (45) having optical path there between. 9. A panoramic viewing device as claimed in claim 1 wherein said sighting tube assembly (8) comprises an eyepiece graticule (40) disposed between the said relay lens assembly (16) and the said eyepiece assembly (17). 10. A panoramic viewing device as substantially described and illustrated herein with reference to accompanying drawings.

Documents:

1465-del-1999-abstract.pdf

1465-del-1999-claims.pdf

1465-del-1999-correspondence-others.pdf

1465-del-1999-correspondence-po.pdf

1465-del-1999-description (complete).pdf

1465-del-1999-drawings.pdf

1465-del-1999-form-1.pdf

1465-del-1999-form-19.pdf

1465-del-1999-form-2.pdf

1465-del-1999-form-3.pdf

1465-del-1999-gpa.pdf