Optical Data Insertion

Abstract

A viewer for an optical data insertion device and a combined system comprising a viewer and an optical data insertion device. The optical data insertion device comprising a projector operable to project a visible image and a light guiding device operable to direct light from the projector into the viewer. The viewer comprising an objective lens, an eyepiece lens and a diffuser screen provided between the objective lens and the eyepiece lens.

Claims

1. A viewer device for use with an optical data insertion device of the type comprising a projector operable to project a visible image and a light guiding device operable to direct light from the projector into another optical device, the viewer device comprising: an objective lens, an eyepiece lens and a diffuser screen provided between the objective lens and eyepiece lens.

2. The viewer device of claim 1, wherein the diffuser screen is provided at the real image plane of the objective lens.

3. The viewer device of claim 1, wherein the diffuser screen is provided within a field stop aperture.

4. The viewer device of claim 1, wherein the diffuser screen is arranged substantially perpendicular to the optical axis of the viewer device.

5. The viewer device of claim 1, wherein the diffuser screen has a structure that is not visible to the human eye at the level of magnification provided by the eyepiece lens.

6. The viewer device of claim 1, wherein the diffuser screen comprises a fibre bundle.

7. The viewer device of claim 6, wherein the fibres comprising the fibre bundle each have a diameter of 4 ?m or less.

8. The viewer device of claim 1, wherein the diffuser screen comprises ground glass.

9. The viewer device of claim 8, wherein the grit particle size used for grinding the glass is in the range 120-600 grits or is greater than 600 grits.

10. The viewer device of claim 1, wherein the diffuser screen comprises a holographic diffuser or a micro-structure diffuser.

11. The viewer device of claim 1, wherein the viewer device is provided within a substantially tubular elongate and substantially opaque housing.

12. The viewer device of claim 11, wherein the objective lens is provided within an inlet aperture at a first end of the housing and the eyepiece lens is provided within an outlet aperture at a second end of the housing, distal to the first end.

13. An optical system comprising a viewer device according to claim 1, and an optical data insertion device comprising a projector operable to project a visible image and a light guiding device operable to direct light from the projector into the viewer device.

14. The optical system of claim 13, wherein the viewer device is positioned relative to the light guiding device such that the light emitted from the light guiding device is directed substantially into the center of the objective lens and/or is substantially aligned with the optical axis of the viewer device.

15. The optical system of claim 13, wherein the projector is adapted to project an image captured by another imaging device.

16. The optical system of claim 13, wherein the intensity of light emitted by the projector is variable.

17. The optical system of claim 16, wherein the elongate body is narrow relative to the inlet aperture of the viewing device.

18. The optical system of claim 13, wherein the light guiding device comprises an elongate light transmitting body, the body tapering from a wider end to a narrower end, the wider end adapted to provide a receiving surface for receiving incident light travelling in the first direction and the narrower end adapted to provide an exit aperture orientated to such that light exits the light guiding device in a second, different, direction.

19. The optical system of claim 13, wherein the optical system comprises a further optical device aligned with the viewer device.

20. The optical system of claim 19, wherein the further optical device and the viewer device are mounted to a common structure.

21. The optical system of claim 19, wherein the further optical device is aligned with and in front of the inlet aperture of the viewer device.

22. The optical system of claim 21, wherein the optical system and the further optical device are mounted such that relative motion is possible.

23. The optical system of claim 22, wherein relative motion is facilitated by rotating the optical system and/or the further optical device out of alignment.

24. The optical system of claim 19, wherein the further optical device is aligned with and behind the outlet aperture of the viewer device.

25. The optical system of claim 19, wherein the further optical device is a sight.

26. The optical system of claim 25, wherein the sight is a red dot sight.

27. The optical system of claim 19, wherein an additional further optical device may be provided aligned with and in front of the inlet aperture of the viewer device or aligned with and behind the outlet aperture of the viewer device.

28. A directional apparatus comprising an optical system according to claim 13.

29. The directional apparatus of claim 28, wherein the directional apparatus is a weapon.

30. The directional apparatus of claim 28, wherein an external power source for the optical system is mounted to the directional apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] For the purpose of illustrating the disclosure, the drawings show aspects of one or more embodiments of the disclosure. However, it should be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:

[0045] FIG. 1 is an illustration of an image intensifier provided with an optical data insertion device in the form of a clip on attachment, as known from the prior art;

[0046] FIG. 2a is an illustration of an optical system comprising a prior art viewer device and an optical data insertion device of the type known from FIG. 1;

[0047] FIG. 2b is an illustration of an optical system comprising a viewer device according to the present invention and an optical data insertion device of the type known from FIG. 1;

[0048] FIG. 3a is a schematic ray diagram illustrating the structure and operation of the prior art viewer device;

[0049] FIG. 3b is a schematic ray diagram illustrating the structure and operation of the viewer device according to the present invention;

[0050] FIGS. 4(a), 4(b), and 4(c) schematically illustrate an optical system according to the present invention fitted to a weapon FIG. 4(a) in place of a sight, FIG. 4(b) behind a red dot sight, and FIG. 4(c) in front of a red dot sight; and

[0051] FIGS. 5(a), 5(b), 5(c) and 5(d) schematically illustrate another embodiment of an optical system according to the present invention rotatably mounted to a weapon behind a red dot sight, in particular FIG. 5(a) illustrates a side view with the optical system in use, FIG. 5(b) is a side view with the optical system rotated away from use, FIG. 5(c) is a top view of the optical system rotated away from use and FIG. 5(d) is a front view the optical system rotated away from use.

DETAILED DESCRIPTION

[0052] Turning to FIG. 1, an optical data insertion device 10 is used to inject optical data into an image intensifier 20. The optical data insertion device 10 can be secured to the image intensifier in use by any suitable means, including the clip 19 illustrated in FIG. 1. An example of such a system is described in more detail in GB2472516A. In summary, the optical data insertion device comprises a thermal imager 11 operable to capture a thermal image in response to infrared light incident on imaging aperture 12 and a projector 13 operable to project a visible image based on that captured by the thermal imager 12. In addition or alternatively, the projector 13 can project other data, for instance alphanumeric ranging data messages or the like. The optical data insertion device 10 further comprises a light guiding device 14.

[0053] The light guiding device 14 is adapted to direct light through an exit aperture 15 (not shown in FIG. 1) into and along the optical axis of the inlet aperture 21 of image intensifier 20. The light guiding device 14 is provided with an opaque housing and is constructed to be a thin as possible in order to minimize the obstruction to the inlet aperture 21. Accordingly, the image intensifier 20 will ultimately provide a combined image based on light from the environment incident on inlet aperture 21 and light from the light guiding device 14. The combined image is viewable though outlet aperture 22, which may be protected by an eye guard 23 as illustrated in FIG. 1.

[0054] In the example described in GB2472516A, the light guiding device 14 comprises an elongate light transmitting solid body, the body tapering from a wider end to a narrower end. The wider end is adapted to provide a receiving surface for receiving incident light, typically from the projector. The narrower end is adapted to provide an exit surface for said incident light and a reflector is provided adjacent to the narrower end, the reflector adapted to receive said incident light from the exit surface and reflect said incident light through the exit aperture 15. In view of the constrictions on the dimensions of the light guiding device 14, the exit aperture 15 of the light guiding device 14 necessarily is relatively small and hence has a small numerical aperture (NA).

[0055] Given the relatively convenient size and weight of the optical data insertion device 10, there is a desire to use the optical data insertion device 10 without the image intensifier 20. Since it impractical to view the exit aperture 15 of the light guiding device 14 the optical data insertion device might typically be clipped to a viewer device 30 using clip 19.

[0056] FIG. 2a illustrates a prior art viewer device 30 comprising a substantially tubular housing 31 provided with an inlet aperture 32 at one end and an outlet aperture 33 at another end. The outlet aperture 33 may be provided with an eye guard 34. In use, the inlet aperture 32 is positioned adjacent to and aligned with the exit aperture 15 of the light guiding device 14. As with the example shown in FIG. 1, a light guiding device 14 that is a thin as possible is beneficial to minimize the obstruction to the inlet aperture 32.

[0057] FIG. 2b shows a viewer device 30 according to the present invention. The viewer device 30 of FIG. 2b is outwardly similar to the viewer device 30 of FIG. 2a. For example, the viewer device 30 of FIG. 2b comprises a substantially tubular housing 31 provided with an inlet aperture 32 at one end and an outlet aperture 33 at another end. In use, the inlet aperture 32 is positioned adjacent to and aligned with the exit aperture 15 of the light guiding device 14. As before, a light guiding device 14 that is a thin as possible is beneficial to minimize the obstruction to the inlet aperture 32. Unlike the optical data insertion device 10 of FIG. 2a, the optical data insertion device 10 of FIG. 2b is additionally provided with a cable 39 which can provide for an external power and/or data connection. The more important differences between the viewer devices 30 of FIGS. 2a and 2b are in the internal construction as illustrated in FIGS. 3a and 3b.

[0058] Turning to FIG. 3a, a ray diagram illustrating the construction and operation of the prior art viewer device 30. The prior art viewer device 30 is provided with an objective lens 35 within the inlet aperture 32 and an eyepiece lens 36 provided within the outlet aperture 33. Each of the objective lens 35 and eyepiece lens 36 can be a single lens (as is the objective lens 35 of FIG. 3) or may be formed from multiple lens elements (as is the case with the eyepiece 36 lens of FIG. 3). A field stop aperture 37 may be provided so as to prevent off axis rays from adversely impacting operation.

[0059] In the prior art viewer device 30, the size of the virtual image VI at the eye is determined by the effective aperture size and the magnification of the objective lens 35 and eyepiece lens 36. For a system with unity magnification, the virtual image VI is essentially the same size as the exit aperture of the light guiding device (say ?1.25 mm as in FIG. 3). Accordingly, the inserted data can only be seen if the eye and light guiding device are precisely aligned.

[0060] In instances where the viewer device 30 inverts incident light, the projector 13 may be configured to invert projected data. This can compensate for the inversion applied by the viewer device 30.

[0061] Turning now to FIG. 3b, a ray diagram illustrating the construction and operation of a viewer device 30 according to the present invention is shown. The key difference is that the viewer device 30 of the present invention is provided with a diffuser screen 38. As shown in the example, the diffuser screen 38 is arranged substantially perpendicular to the optical axis of the viewer device 30. As illustrated in FIG. 3b, the diffuser screen 38 is provided within a field stop aperture 37 so as to prevent off axis rays from adversely impacting operation. The diffuser screen 38 is typically provided at the real image plane of the objective lens 35, so as to limit unwanted distortion of the inserted optical data.

[0062] In use, as is illustrated in FIG. 3b, the diffuser screen re-emits or scatters the inserted light from each point in the image into a wide cone of light not dependent on the incoming angle of the inserted light. This effectively regenerates an expanded input image with a numerical aperture (NA) equivalent to the size of the diffuser screen 38. The diffuser screen 38 image is thus larger and visible over a wider viewing aperture than would be the case for an image directly based on the exit aperture 15 of the light guiding device 14.

[0063] The diffuser screen 38 can optionally be of any suitable type or construction. For example, suitable diffuser screen 38 types/constructions include but are not limited to any one of fibre bundles, ground glass, holographic diffusers, micro-structure diffusers prismatic diffusers, louvres, and reflectors. In selecting a particular type and specification of diffuser screen 38, the skilled person will bear in mind that coarser diffuser structure provides enhanced diffusion performance, thereby increasing visibility of the virtual image VI but also increases distortion of the virtual image VI. Conversely, finer diffuser structure provides less diffusion and thus a less visible virtual image VI but also means that less of the surface disruption is visible under magnification.

[0064] Turning now to FIGS. 4(a)-4(c), examples of the viewer device 30 of the present invention used with the optical data insertion device 10 to provide an optical system 40 according to the present invention. As is illustrated in FIGS. 5(a)-5(d), the optical system 40 is used with a weapon 50. The skilled person will appreciate that the optical system 40 can equally be used with other directional apparatus for example, sensing systems, imaging systems or cameras, targeting devices or the like.

[0065] In the examples of FIGS. 4(a)-4(c), the weapon 50 is a rifle. In the example shown, the rifle 50 comprises barrel 51 at front end of the rifle 50 and a stock 52 at an opposing end of the rifle 50. Projecting from a lower side of the rifle 50 is a handle 53. Additionally projecting from the lower side of rifle 50 are trigger 54 and trigger guard 55. On an upper side of the rifle 50 is provided a mounting rail 56.

[0066] In FIG. 4a, the optical system 40 is fitted to mounting rail 56 and aligned with the barrel 51. Accordingly, the optical system 40 can function as a sight for rifle 50. In such cases, the user of rifle 50 can view an image in visible light of the target area for barrel 51 along with any information (such as an equivalent view in infrared) inserted via optical data insertion device 10.

[0067] Turning now to FIG. 4b, the rifle 50 differs only from that of FIG. 5a in that a red dot type sight 60 is also fitted to the mounting rail 56. In this example, the in the red dot sight is positioned in front of the optical system 40 and aligned with the inlet aperture 32 of the viewer device 30. Accordingly, the optical system 40 can relay the view provided by red dot sight 60 to a user, including the red dot indicating alignment of the barrel 51. Additionally, any desired information (such as an equivalent view in infrared) can be inserted via optical data insertion device 10.

[0068] Turning now to FIG. 4c, this differs from FIG. 5b in that the red dot sight 60 is positioned behind rather than in front of the optical system 40 and aligned with the outlet aperture 33 of the viewer device 30. Accordingly, the red dot sight 60 relays the image in visible light of the target area viewable though the viewing device and any information (such as an equivalent view in infrared) inserted via optical data insertion device 10 to the user, overlaid with a red dot indicating alignment of the barrel 51.

[0069] The selection of whether to have red dot sight 60 in front of optical system 40 as in FIG. 4b or to have red dot sight 60 behind optical system 40 as in FIG. 4c, will depend on preference and/or intended operation.

[0070] Turning now to FIGS. 5(a)-5(d), this illustrates that the optical system 40 can be mounted to the rail 56 by way of a rotatable bracket. This allows the optical system 40 to be rotated relative to red dot sight 60 from an in use position in FIG. 5a to an out of use position shown in FIGS. 5b-5d. This can enable a user to rapidly switch between viewing through both the red dot sight 60 and optical system 40 or just the red dot sight 60.

[0071] The skilled person will appreciate that in alternative embodiments, the optical system 40 could rotate toward the other side of the weapon 50. The skilled person would also appreciate that the red dot sight 60 could be mounted to the rail 56 via a rotatable bracket. This might allow a user to rapidly switch between viewing through both the red dot sight 60 and optical system 40 or either device individually. Similarly, the skilled person will appreciate that the mounting position of red dot sight 60 and/or optical system 40 can be adjusted relative to each other along the axis of the weapon 50.

[0072] FIGS. 5(a)-5(d) further illustrate the provision of an external power source in the form of a battery 70 for the optical data insertion device 10. The battery can be mounted to the weapon 50 in a convenient location as shown in FIGS. 5(a)-5(d). The battery 70 can be connected to the optical data insertion device 10 by a power cable 39.

[0073] The skilled person will appreciate that in the examples of FIGS. 4(a)-4(c) and 5(a)-5(d), different weapons could be substituted for the rifle 50. Similarly, the skilled person will appreciate that other types of reflector or reflex sight may be substituted for a red dot sight where appropriate.

[0074] The one or more embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.

[0075] Various modifications and additions can be made without departing from the spirit and scope of this disclosure. Features of each of the various embodiments described above may be combined with features of other described embodiments as appropriate in order to provide a multiplicity of feature combinations in associated new embodiments. Furthermore, while the foregoing describes a number of separate embodiments, what has been described herein is merely illustrative of the application of the principles of the present disclosure. Additionally, although particular methods herein may be illustrated and/or described as being performed in a specific order, the ordering is highly variable within ordinary skill to achieve aspects of the present disclosure. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this disclosure.

[0076] Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. It will be understood by those skilled in the art that various changes, omissions and additions may be made to that which is specifically disclosed herein without departing from the spirit and scope of the present disclosure.