Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G1/00—Sighting devices
  • F41G1/06—Rearsights
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/32—Holograms used as optical elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G1/00—Sighting devices
  • F41G1/30—Reflecting-sights specially adapted for smallarms or ordnance
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G1/00—Sighting devices
  • F41G1/32—Night sights, e.g. luminescent
  • F41G1/34—Night sights, e.g. luminescent combined with light source, e.g. spot light
  • F41G1/345—Night sights, e.g. luminescent combined with light source, e.g. spot light for illuminating the sights
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
  • G02B23/14—Viewfinders
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/18—Diffraction gratings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/18—Diffraction gratings
  • G02B5/1861—Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
  • G02B5/203—Filters having holographic or diffractive elements
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
  • G03H1/2286—Particular reconstruction light ; Beam properties
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
  • G02B5/22—Absorbing filters
  • G02B5/223—Absorbing filters containing organic substances, e.g. dyes, inks or pigments
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
  • G03H1/2202—Reconstruction geometries or arrangements
  • G03H2001/2223—Particular relationship between light source, hologram and observer
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
  • G03H1/2249—Holobject properties
  • G03H2001/2284—Superimposing the holobject with other visual information
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2223/00—Optical components
  • G03H2223/15—Colour filter, e.g. interferential colour filter
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2223/00—Optical components
  • G03H2223/23—Diffractive element

Definitions

• the present disclosure relates to components within a holographic sighting device preferably for use on firearms.
• a holographic sight In a holographic sight, a laser beam of light is transmitted through a housing and is reflected one or more times until an aiming reticle image is generated by a hologram element. Diffraction gratings can be implemented in these and other types of optical sights. The diffraction grating spatially directs light in the laser beam as the wavelength changes with temperature.
• the Lightweight Holographic Sight disclosed in U.S. Patent No. 6,490,060 issued to Tai et al. describes a compact and lightweight design of a holographic sight includes a grating that can also rotate in two axes to adjust light reflected from the grating and shift the aiming reticle.
• VPGs emulsion-based holographic volume phase gratings
• Other prior gratings are inherently durable, but lack angular and wavelength selectivity.
• ruled metal-on-glass gratings and metal-on-epoxy replicated gratings are capable of diffracting over wide ranges of wavelengths, including multiple orders of each input wavelength.
• Each output angle may include primary and higher diffraction orders unless order-sorting filters are added to the optical path. It is therefore desirable to combine wavelength selectivity and durability within a single grating technology.
• Unfiltered ambient light might enter the housing of the optical sight. This unwanted ambient light can sometimes disrupt the view of the reticle image. This is at least partially due to the ambient light diffracting and reflecting back to the user, causing a visible spectrum of light (i.e., a rainbow) or bright mirror reflections. It is thus desirable to provide a weapon sight that reduces negative effects of ambient light (such as glare) without increasing the size of the sight. It is also desirable to improve existing weapons sights to reduce the negative effects of ambient light while considering the cost, weight, and number of parts in the sight.
• a holographic weapons sight comprises a reticle image hologram and an integrated grating and filter device.
• the integrated grating and filter device includes a base substrate and a transparent substrate spaced from the base substrate.
• a first epoxy is between the substrates and contacts the base substrate.
• the first epoxy includes an outer surface having a series of surface features molded thereon.
• a reflective coating contacts the outer surface of the first epoxy and is configured to diffract light toward the hologram.
• a dyed epoxy is between the reflective coating and the transparent substrate. The dyed epoxy is adapted to inhibit at least a portion of the light from reflecting to the hologram.
• the surface features, the reflective coating, and the dyed epoxy may each include a series of ridges and grooves, wherein the ridges and grooves of the reflective coating contact the ridges and grooves of both the transparent epoxy and the dyed epoxy.
• the dyed epoxy may be dyed red and may be adapted to inhibit light having a wavelength of approximately less than 575nm from passing through the dyed epoxy.
• the dyed epoxy may also be died green and may be adapted to inhibit a light having a wavelength of approximately 475 nm - 610 nm from passing through the dyed epoxy.
• the reflective coating may be a layer of metal, such as aluminum, and the base substrate and first epoxy may be transparent.
• a holographic sight comprises a laser diode, a diffraction grating, and an optical filter.
• the laser diode is configured to emit a light beam.
• the diffraction grating has a grating surface configured to diffract the light beam toward the hologram, but also diffract ambient light.
• the optical filter contacts at least a portion of the grating surface and is adapted to absorb at least one wavelength of the ambient light.
• the optical filter may directly contact the grating surface of the diffraction grating.
• the optical filter may indirectly contact the grating surface while being integrated with the grating surface.
• the optical filter may be arranged in the sight such that it absorbs the at least one wavelength of ambient light prior to the ambient light ever transmitting to the grating surface of the diffraction grating. In such an embodiment, all ambient light must pass through the filter before reaching the grating.
• the diffraction grating may include a layer of epoxy and a layer of a reflective metal bonded to at least a portion of the epoxy.
• the epoxy may include a series of molded ridges and grooves directly contacting the layer of reflective metal.
• the optical filter may include a dyed-epoxy directly contacting the layer of refiective metal opposite the epoxy.
• the optical filter and the diffraction grating may be disposed between opposing layers of glass.
• a holographic sight comprises a laser diode for emitting a light beam, a collimator that collimates light emitted from the light beam, a reflective diffraction grating having a grating surface for diffracting the collimated light, and a filter contacting at least a portion of the grating surface.
• the reflective diffraction grating and the filter may be integrated into a unitary device.
• the filter and grating may be bonded to one another in which a dyed transparent material acting as the filter is bonded to a first glass substrate and to the reflective diffraction grating which includes a molded epoxy bonding a layer of refiective material to a second glass substrate.
• FIGURE 1 is a plan perspective view of a holographic sight mounted on a rifle.
• FIGURE 2 is a schematic side view of the holographic sight illustrating the layout of optical components and the path of light through the sight.
• FIGURE 3 is a cross-sectional schematic of a grating with an integrated filter according to one embodiment.
• FIGURE 4 is a detailed schematic illustration of the integrated grating and filter according to one embodiment.
• FIGURES 5-8 are graphical representations of one exemplary filter integrated with the grating and its effect on daylight and the laser light according to one embodiment.
• FIGURES 9-12 are graphical representations of another exemplary filter integrated with the grating and its effect on daylight and the laser light according to another embodiment.
• holographic weapons sight is shown mounted on a weapon 12.
• the weapon 12 is shown as an M4 rifle, however it should be understood that the weapon may be other arms, including, for example, rifies, shotguns, handguns, grenade launchers, bows, or any other such handheld or vehicle-mounted weapon.
• the sight 10 may include certain components disclosed in U.S. Patent No. 6,490,060 issued to Tai et al, directed to a Lightweight Holographic Sight, the disclosure of which is incorporated by reference herein. It is also contemplated that the sight 10 may be mounted on other non-weaponry devices in which a user aims the device in a specific direction.
• the sight 10 may be utilized with astronomical telescopes, terrestrial survey equipment, RADAR/LIDAR guns for law enforcement agents, Crew Optical Alignment Sights (COAS) for spacecraft pilots, cameras, search lights, stage lighting, highly directional microphones.
• COAS Crew Optical Alignment Sights
• Other such embodiments are contemplated and should be considered within the scope of the present disclosure.
• the holographic sight 10 is illustrated including optical components and an optical path of light that reflects off the optical components.
• the sight 10 includes a laser diode 14 that produces a beam of light in a diverging manner.
• the laser beam reflects or "folds" generally upward from a folding mirror 16 toward a reflective collimator 18.
• the light beam becomes collimated (i.e., parallel or non-diverging) after it is reflected off the collimator 18 and is directed generally downward toward a holographic integrated grating and filter device 20, the components of which will be discussed further below.
• the integrated grating and filter device 20 diffracts the laser light generally upward to a hologram 22, which is recorded with a projected image of a reticle pattern.
• the reticle image is then viewable by a user looking through the hologram.
• the diode 14, mirror 16, collimator 18, integrated grating and filter device 20, and hologram 22 are all mounted within a housing 24 secured to an integral or separate base 26.
• the arrangement of the components within the sight 10 is merely exemplary, and other arrangements and configurations known in the art are considered to be within the scope of the present disclosure.
• a filter is integrated with the grating as part of a unitary component to diffract the light from the laser diode 14.
• the grating and filter being integrated, as opposed to separated, provides a variety of advantages.
• the integrated grating and filter reduces the spaced occupied in the housing 24 by the filter(s) and grating(s), reduces the number of optical elements required in the sight 10, reduces the weight of the sight 10, and reduces the assembly cost of the sight 10.
• the integrated grating and filter also simplifies the alignment of the optical components and reduces reflective losses that might otherwise be realized between a separated grating and filter.
• the filter when the filter is in (direct or indirect) contact with the grating, the filter can serve as a protective layer by inhibiting damage to the grating.
• the integrated grating and filter device 20 is particularly useful in inhibiting stray or ambient light from interfering with covert usage of the sight.
• sunlight that enters the housing 24 may reflect off of the grating, creating a visible specular reflection that can interfere with the user's vision when looking through the sight, or causing spurious reflections visible to an adversary or prey.
• the sunlight can be filtered directly at the grating such that excess spectrum is inhibited from reflecting from the grating.
• FIG. 3 illustrates such a grating and filter integral in a single device, shown schematically at 20.
• the filter and the grating are generally indicated by 30 and 32, respectively.
• the filter 30 is shown in Figure 3 as directly contacting the grating 32 in which at least a portion of the filter 30 directly touches at least a portion of the grating 32.
• an intermediate material e.g., adhesive, oil, glass, ceramic
• the intermediate material may help to bind or otherwise adhere the filter 30 to the grating 32.
• Both indirect contact and direct contact between the filter 30 and the grating 32 are contemplated and both embodiments are intended to be within the scope of what is mean by "contact" between the filter 30 and the adjacent grating 32.
• a first layer or outer layer of glass 34 provides a cover to the filter 30.
• a second layer or inner layer of glass 36 provides a boundary opposite the outer layer of glass 34 such that the filter 30 and grating 32 are sandwiched between the two layers of glass.
• the inner layer of glass 36 is mounted or otherwise secured to a portion of the housing 24 or another component therein.
• the grating 32 and the filter 30 are disposed between the two layers of glass 34, 36.
• the grating 32 may be, for example, a thin aluminum film or coating.
• a layer of (preferably clear) two-part epoxy 40 bonds or adheres the grating 32 to the inner layer of glass 36.
• Opposite the clear epoxy 40 from the grating 32 is the integrated filter 30.
• the filter 30 may be a dyed or colored (e.g., red) two-part epoxy.
• the grating selectively diffracts and reflects incoming laser light 42 while the colored-dyed epoxy filter 30 filters the reflected and diffracted laser light 42 and ambient light 43 to allow only a narrowed range of wavelengths of light to deflect away from the integrated grating and filter unit 20 (as will be additionally described with reference to Figures 5-12).
• the diffraction grating 32 can be of any type suitable for a holographic sight.
• the grating 32 has grating features, including a series of regularly spaced ridges 44 and grooves 46. This is but one example, and the grating 32 may include any suitable type of grating features known in the art for diffracting the incoming light.
• the grating 32 can include a plurality of substantially linear periodic grating features and/or a plurality of curved grating features.
• the grating include a variety of shapes, including triangular, sinusoidal, square, rectangular, etc.
• the grating features of the grating 32 can correspond to opaque, periodic (or quasiperiodic) rulings arranged within a transparent substrate, or can correspond to a plurality of domains with different indices of refraction, as might be observed in a volume phase diffraction grating.
• the filter 30 can also be of any type suitable for a holographic sight.
• the filter 30 is an order-sorting filter configured to transmit at least a portion of the incoming light incident upon the filter 30 and absorb and/or reflect away at least another portion of the light incident upon the filter 30.
• the filter 30 is an absorption filter that absorbs one or more particular wavelengths of light such that those wavelengths are not transmitted through the absorption filter.
• the absorption filter includes an absorptive medium, which generally refers to the spatial portion within which absorption is achieved by the absorption filter.
• the absorptive medium can include a layer (e.g., a liquid and/or a solid) that contains a dye or other absorptive additive.
• the integrated filter 30 and grating 32 can be made utilizing several manufacturing techniques.
• a mold is provided having the shape of the surface features of the grating (e.g., the ridges 44 and grooves 46 of the surface).
• a thin film of aluminum is deposited onto the mold via evaporation in which a vacuum allows vaporous aluminum particles to coat the mold.
• a clear layer of epoxy is then distributed onto the aluminum coating within the mold.
• a layer of glass is placed over the clear layer of epoxy.
• the molded structure can be removed from the mold, and cut or broken to shape (after adding the filter portion, described below). The mold can then be reused for subsequent grating creation. The molded structure can be flipped such that the aluminum layer is prepared to interact with a red-dyed epoxy, as described below.
• the filter portion of the integrated grating and filter device 20 is formed.
• a layer of red-dyed epoxy is poured or otherwise dispensed directly to the aluminum layer of the previously-formed grating.
• the red-dyed epoxy binds to the layer of aluminum, filling the grooves 46 and forming a solid continuous bonding layer.
• a layer of glass is then placed over, and optionally pressed onto, the red-dyed epoxy.
• the entire structure is allowed to cool and set.
• the integrated grating and filter device 20 is formed, including the red-dyed epoxy providing a filter 30 in contact with an aluminum layer held between two glass substrates 34, 36.
• the final formed integrated grating and filter device 20 can have dimensions of approximately one inch in height by one inch in width by 0.125 inch in thickness. This is but one example of the dimensions of the device 20.
• Figures 3-4 illustrate the filter 30 and grating 32 as being separate but integrated elements that are bonded or otherwise secured to one another in a contacting manner.
• the filter 30 and grating 32 can be formed of a unitary material.
• the filter 30 may be a formed of a glass, polymer, ceramic, or other material and may comprise an absorptive additive such as a dye.
• grating features may be formed onto one side of the filter, thereby forming a unitary integrated grating and filter in which the grating and filter are both defined by one layer of a single material.
• the grating features may be embossed into or deposited onto a surface of the filter.
• the materials of the integrated grating and filter device 20 are merely exemplary and are not intended to be limited.
• either or both layers of glass 34, 36 may instead be of ceramic, silicon, plastic, or composite materials (e.g., combinations of polymers, metals, glass, and/or ceramics).
• the surface of the grating 32 may comprise nickel, copper, titanium, chromium, gold, silver, other reflective metals, or a non-metal material suitable for reflection and diffraction.
• Figures 5-8 illustrate the effects that the integrated grating and filter device 20 has on daylight as well as light produced from the laser diode.
• Figure 5 shows the input of daylight and the laser light into the sight 10.
• the filter is a red- dyed epoxy that effectively inhibits all visible light having a wavelength of less than approximately 575 nm from transmitting therethrough.
• the particular filter exemplified in Figure 5 allows for the passage of red light (e.g., -650 nm) that is produced by the laser diode and present in the ambient light.
• red light e.g., -650 nm
• the filter can alternatively include a dye of a different color to allow the reflection of other wavelength ranges.
• Figure 6 illustrates the effect of the filter on the daylight and the light emitting from the laser diode.
• the portions of the daylight having wavelengths less than approximately 575 nm are effectively filtered and inhibited from reflecting from the integrated grating and filter device 20.
• the wavelengths of daylight above 575 nm are reduced by approximately 30% due to the characteristics of the filter (shown in Figure 5).
• the red light emitting from the laser diode is also reduced as it travels through the filter.
• Figure 7 illustrates a comparison between unfiltered daylight and filtered daylight.
• the integrated grating and filter device 20 Because of the integrated grating and filter device 20, the entire spectrum of visible light up to approximately 575 nm is filtered and is unable to reflect to the user or otherwise exit the sight. This eliminates any "rainbow glare" that may be realized by a user of the sight in which unfiltered daylight could otherwise diffract and reflect back to the user, impeding the vision of the user.
• Figure 8 illustrates a comparison between the unfiltered laser light and the filtered laser light.
• the entire spectrum of color produced by the laser e.g., red
• the integrated grating and filter device 20 can be interchanged with another integrated device having different filtering characteristics.
• a green-dyed epoxy can be utilized instead of a red-dyed epoxy.
• the effects of a green filter on daylight and a green laser light are illustrated in Figures 9-12, similar to the effects illustrated in Figures 5-8.
• the green filter used to produce the results of Figures 9-12 effectively inhibits all visible light having wavelengths outside of a range of 475 nm - 610 nm from transmitting through the filter.
• the single integrated device can be interchanged with other integrated devices with different filter characteristics.
• a sight with this device is provided with a reduction of the negative effects of ambient light (such as glare) in a weapon sight without increasing the size of the sight or the necessity to redesign the sight to implement a filter device separated from the grating.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Astronomy & Astrophysics (AREA)
• Diffracting Gratings Or Hologram Optical Elements (AREA)
• Holo Graphy (AREA)
• Optical Filters (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (2)

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• 2014
  • 2014-05-09 US US14/274,057 patent/US9482803B2/en active Active
• 2015
  • 2015-05-11 EP EP15828263.2A patent/EP3140606B1/en active Active
  • 2015-05-11 WO PCT/US2015/030074 patent/WO2016018489A2/en not_active Ceased
  • 2015-05-11 JP JP2017511570A patent/JP6770950B2/ja active Active
  • 2015-05-11 BR BR112016026265-4A patent/BR112016026265B1/pt active IP Right Grant
  • 2015-05-11 CN CN201580034911.9A patent/CN106716048B/zh active Active
  • 2015-05-11 CA CA2948669A patent/CA2948669C/en active Active
  • 2015-05-11 RU RU2016144905A patent/RU2677608C2/ru active
• 2016
  • 2016-11-08 IL IL248822A patent/IL248822B/en unknown

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