# US 5,349,179 A · Night vision device with holographic reticle which is transparent in a first condition and visibly superimposed in a second condition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,349,179 A - Document ID: US5349179A - Status: Granted - Kind: A - Application number: 08/086,522 - Filed: 1993-07-01 - Granted: 1994-09-20 - Earliest claimed: 1993-07-01 - Assignees: Litton Systems, Inc. - Inventors: Roland M. Morley - Web page: https://patentgrep.com/patent/US5349179A ## CPC - G02B 27/34: illuminated - G02B 23/10: reflecting into the field of view additional indications, e.g. from collimator - G02B 23/125: {head-mounted} - G03H 1/22: Processes or apparatus for obtaining an optical image from holograms (G03H1/26 - G03H1/34 take precedence) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00}) ## Abstract A night vision device with a holographic reticle ordinarily provides a user with all image of a night time scene unimpaired by any reticle pattern. Such a reticle pattern can interfere with night time observations, or may be distracting to the user. Consequently, the utility of the night vision device for use by observers is improved. However, when the holographic reticle is activated, the user is provided with a clearly visible reticle pattern superimposed on the night time scene. The reticle pattern may be used, for example, to estimate ranges to objects observed, or to aim a weapon. ## Claims ### Claim 1 A viewing device comprising: an objective lens through which light from a scene is received; an eye piece through which an image of the scene is provided to a user of the device; and an optical pathway extending between said objective lens and said eye piece; a holographic reticle disposed in said optical pathway and being substantially completely transparent in a first condition, in a second condition said holographic reticle providing a holographic reticle pattern visible in said eye piece and superimposed on the scene image. ### Claim 2 (depends on 1) The viewing device of claim 1 wherein said optical pathway also includes a focal plane, said holographic reticle being spaced from said focal plane and in the second condition providing said holographic reticle pattern at said focal plane for viewing through the eye piece. ### Claim 3 (depends on 2) The viewing device of claim 2 wherein said device further includes an image intensifier tube adapting the device particularly for viewing night scenes of low-level illumination. ### Claim 4 (depends on 1) The viewing device of claim 1 where in said holographic reticle is substantially invisible in its first condition and provides an unobstructed view through the eye piece, in the second condition of said holographic reticle said holographic reticle pattern being visible in said eye piece. ### Claim 5 (depends on 1) The viewing device of claim 1 wherein said reticle pattern includes features for estimating a range to objects observed with said device. ### Claim 6 (depends on 5) The viewing device of claim 5 wherein said reticle pattern includes features for aiming a weapon. ### Claim 7 (depends on 1) The viewing device of claim 1 wherein said holographic reticle includes a photosensitive holographic medium. ### Claim 8 (depends on 7) The viewing device of claim 7 wherein said holographic medium is selected from the materials including dichromated gelatin, and silver halide. ### Claim 9 (depends on 8) The viewing device of claim 8 wherein said holographic reticle includes a glass plate. ### Claim 10 (depends on 9) The viewing device of claim 9 wherein said holographic reticle includes a pair of glass plates sandwiching said photosensitive holographic medium therebetween. ### Claim 11 (depends on 1) The viewing device of claim 1 wherein said holographic reticle provides a holographic reticle pattern in said second condition when illuminated by exciting light. ### Claim 12 (depends on 11) The viewing device of claim 11 wherein said exciting light for said holographic reticle is provided by a light emitting diode. ### Claim 13 (depends on 12) The viewing device of claim 12 wherein said light emitting diode is selected to provide light substantially of substantially 645 NM wavelength, and with a spectral line width of substantially 20 NM. ### Claim 14 (depends on 11) The viewing device of claim 11 wherein said optical pathway includes a mirror, said mirror defining an optical aperture, and said exciting light for said holographic reticle shining thereon via said optical aperture. ### Claim 15 (depends on 1) The viewing device of claim 1 wherein said optical pathway includes an focal plane at which an image visible through said eye piece is formed, said holographic reticle being spaced from said focal plane and providing at said focal plane said holographic reticle pattern in said second condition of said holographic reticle. ### Claim 16 A method of providing a night vision device in a first condition providing a view of a night scene which is unobstructed by any reticle pattern and in a second condition providing a view with a reticle pattern, said method including the steps of: providing the night vision device with an optical pathway including a focal plane at which an image of the night scene is formed; providing a transparent holographic reticle in said optical pathway and spaced from said focal plane; and using said holographic reticle to provide a holographic reticle pattern at said focal plane and superimposed on said night scene image thereat. ### Claim 17 (depends on 16) The method of claim 16 wherein said step of using said holographic reticle to provide said holographic reticle pattern includes the steps of illuminating said holographic reticle with excitation light, and using said excitation light to cause formation of said holographic reticle pattern at said focal plane. ### Claim 18 (depends on 17) The method of claim 17 wherein said method includes the steps of including a mirror in said optical pathway, forming an optical aperture in said mirror, and shining said excitation light through said optical aperture to illuminate said holographic reticle. ### Claim 19 A night vision device comprising: an objective lens for receiving low-level light from a night scene and providing an image of the night scene; an image intensifier assembly receiving said low-level light and providing a visible image representative thereof; an eye piece in which said image is visible; said objective lens, image intensifier assembly, and said eye piece cooperatively defining an optical pathway; and a holographic reticle disposed in said optical pathway for providing a holographic reticle pattern superimposed on said image. ### Claim 20 (depends on 19) The night vision device of claim 19 wherein said holographic reticle includes a photosensitive holographic medium. ### Claim 21 (depends on 20) The night vision device of claim 20 wherein said holographic medium is chosen from the group of materials including dichromated gelatin, and silver halide. ### Claim 22 (depends on 21) The night vision device of claim 21 wherein said holographic reticle includes a glass plate supporting said holographic medium. ### Claim 23 (depends on 22) The night vision device of claim 22 wherein said holographic reticle includes a pair of glass plated sandwiching said holographic medium therebetween. ### Claim 24 (depends on 19) The night vision device of claim 19 further including a mirror reflecting said image to said eye piece and defining an optical aperture, and a light source selected to excite said holographic reticle and cause formation of said holographic reticle pattern, said light source being aligned with said optical aperture to illuminate said holographic reticle.