# US 9,753,268 B2 · Reticle unit, optical instrument, and rifle scope > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,753,268 B2 - Document ID: US9753268B2 - Status: Granted - Kind: B2 - Application number: 13/884,903 - Filed: 2011-10-21 - Published: 2013-10-31 - Granted: 2017-09-05 - Earliest claimed: 2010-10-25 - Assignees: Nikon Vision Co., Ltd. - Applicants: Satoshi Arai; Kenji Shikama; Yosuke Miyazaki - Inventors: Satoshi Arai; Kenji Shikama; Yosuke Miyazaki - Web page: https://patentgrep.com/patent/US9753268B2 ## CPC - G02B 23/02: involving prisms or mirrors (G02B23/14 takes precedence) - F41G 1/12: with line or mark other than notch - F41G 1/345: {for illuminating the sights} - F41G 1/38: Telescopic sights specially adapted for smallarms or ordnance (telescopic sights in general G02B); Supports or mountings therefor {(Means for mounting sighting or aiming devices on firearms F41G11/001)} - G02B 23/14: Viewfinders (for photographic apparatus G03B13/02) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - F41G: WEAPON SIGHTS; AIMING (optical aspects thereof G02B) ## Abstract Provided are a reticle unit that can secure excellent visibility of a reticle regardless of the background and an optical instrument including the reticle unit. A reticle unit 30 used in an optical instrument such as a rifle scope 50 includes: a reflector 32 provided with a concave portion 32b on one of surfaces of a plate-like optical member, wherein at least part of a side surface of the concave portion 32b is a reflection surface 32c; a light source 33 that is arranged laterally to the reflector 32 and that emits light; and a light collector 34 that is arranged between the light source 33 and the reflector 32 and that collects the light from the light source 33 to guide the light to the reflection surface 32c, wherein at least part of the light incident on the reflection surface 32c is totally reflected by the reflection surface 32c and emitted from the other surface of the reflector 32. ## Claims ### Claim 1 A reticle unit comprising: a reflector provided with a concave portion on one of surfaces of a plate-like optical member, wherein at least part of a side surface of the concave portion is a reflection surface; a light source that is arranged laterally to the reflector and that emits light; and a light collector that is arranged between the light source and the reflector and that collects the light from the light source onto a surface substantially parallel to the surface on which at least the concave portion is formed to form an image of the light source on or near the reflection surface, wherein at least part of the light incident on the reflection surface is totally reflected by the reflection surface and the totally reflected light is exited from the reflector, and wherein when an optical axis of the light source and the light collector is defined as a first optical axis, and an optical axis for reflecting the light by the reflection surface to exit the light from the reflector is defined as a second optical axis, a condition of the following expression is satisfied, wherein h denotes a depth in a direction of the second optical axis of the concave portion, Y denotes a diameter of the light source, β denotes a magnification of the light collector, δ denotes an angle formed by the second optical axis and a normal line of the reflection surface, α denotes an angle formed by the second optical axis and the reflection surface, L denotes a height in a direction of the first optical axis of the reflection surface, D denotes a thickness in the direction of the second optical axis of the reflector, and Φ denotes an outer diameter in the direction of the first optical axis of the reflector: y 2 · β · cos ⁡ ( α - δ ) - L 2 ⁢ tan ⁢ ⁢ α < h < D - Φ 2 ⁢ tan ⁡ ( 2 ⁢ δ ) - L 2 ⁢ tan ⁢ ⁢ α . ### Claim 2 (depends on 1) The reticle unit according to claim 1, wherein a condition of the following expression is satisfied: δ=90°−α. ### Claim 3 (depends on 1) The reticle unit according to claim 1, wherein a condition of the following expression is satisfied, wherein φ denotes a maximum outer diameter of the light collector: ϕ > D - Φ 2 ⁢ tan ⁡ ( 2 ⁢ δ ) - L 2 ⁢ tan ⁢ ⁢ α - h . ### Claim 4 (depends on 1) The reticle unit according to claim 1, wherein the angle α formed by the second optical axis and the reflection surface is 45°. ### Claim 5 (depends on 1) An optical instrument comprising: an objective lens; the reticle unit according to claim 1, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light exited from the reflection surface of the reticle unit are placed on top of each other. ### Claim 6 (depends on 1) A rifle scope comprising: an objective lens; the reticle unit according to claim 1, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light emitted from the reflection surface of the reticle unit are placed on top of each other. ### Claim 7 A reticle unit comprising: a reflector provided with a concave portion on one of surfaces of a plate-like optical member, wherein at least part of a side surface of the concave portion is a reflection surface; a light source that is arranged laterally to the reflector and that emits light; and a light collector that is arranged between the light source and the reflector and that collects the light from the light source onto a surface substantially parallel to the surface on which at least the concave portion is formed to form an image of the light source on or near the reflection surface, wherein at least part of the light incident on the reflection surface is totally reflected by the reflection surface and the totally reflected light is exited from the reflector; the reticle unit further comprising a reticle member provided with a reticle on one of the surfaces of the plate-like optical member, wherein the reflector is arranged so that one of the surfaces of the reflector faces the surface provided with the reticle. ### Claim 8 (depends on 7) The reticle unit according to claim 7, wherein the light collector is made of a member different from the reflector and includes a light reflection collection surface in an aspheric shape. ### Claim 9 (depends on 8) The reticle unit according to claim 8, wherein inside of the reflector, the surface of the reflector provided with the concave portion totally reflects the light from the light source, and then the light enters the reflection surface. ### Claim 10 (depends on 7) The reticle unit according to claim 7, wherein the reticle member and the reflector are arranged to have an air space therebetween. ### Claim 11 (depends on 7) The reticle unit according to claim 7, wherein the reticle member and the reflector are arranged by bonding the opposing surfaces. ### Claim 12 (depends on 8) The reticle unit according to claim 8, wherein the light collector is bonded to a side of the reflector. ### Claim 13 (depends on 7) The reticle unit according to claim 7, wherein the light collector is bonded to a side of the reticle member. ### Claim 14 (depends on 13) The reticle unit according to claim 13, wherein inside of the reticle member, the light from the light source is totally reflected by one of the side surfaces of the reticle member, which is not adjacent to the reflector, to guide the light to the reflector. ### Claim 15 (depends on 7) The reticle unit according to claim 7, wherein at least two parts of the side surface of the concave portion are the reflection surfaces, and the reticle unit is provided with the light source and the light collector for each of the reflection surfaces. ### Claim 16 (depends on 7) The reticle unit according to claim 7, wherein the reflection surface is a flat surface. ### Claim 17 (depends on 7) The reticle unit according to claim 7, wherein the reflection surface is a curved surface convex toward the light source. ### Claim 18 (depends on 7) The reticle unit according to claim 7, wherein the reflector is formed of mold processing. ### Claim 19 (depends on 7) The reticle unit according to claim 7, wherein the reflector is formed of resin. ### Claim 20 (depends on 7) An optical instrument comprising: an objective lens; the reticle unit according to claim 7, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light exited from the reflection surface of the reticle unit are placed on top of each other. ### Claim 21 (depends on 7) A rifle scope comprising: an objective lens; the reticle unit according to claim 7, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light emitted from the reflection surface of the reticle unit are placed on top of each other. ### Claim 22 A reticle unit comprising: a reflector provided with a concave portion on one of surfaces of a plate-like optical member, wherein at least part of a side surface of the concave portion is a reflection surface; a light source that is arranged laterally to the reflector and that emits light; and a light collector that is arranged between the light source and the reflector and that collects the light from the light source onto a surface substantially parallel to the surface on which at least the concave portion is formed to form an image of the light source on or near the reflection surface, wherein at least part of the light incident on the reflection surface is totally reflected by the reflection surface and the totally reflected light is exited from the reflector, and wherein when an optical axis of the light source and the light collector is defined as a first optical axis, and an optical axis for reflecting the light by the reflection surface to exit the light from the reflector is defined as a second optical axis, the first optical axis and the second optical axis are substantially orthogonal. ### Claim 23 (depends on 22) The reticle unit according to claim 22, wherein the light collector is a condenser lens that converts the light from the light source to substantially parallel light, and the reflection surface is a curved surface convex toward the light source. ### Claim 24 (depends on 22) The reticle unit according to claim 22, wherein the reflection surface is a toroidal surface in which curvatures are different between a meridional plane, which includes the first optical axis and the second optical axis, and a sagittal plane, which includes an optical axis of the reflection surface and which is perpendicular to the meridional plane, and the optical axis of the reflection surface is tilted substantially 45° relative to the second optical axis. ### Claim 25 (depends on 24) The reticle unit according to claim 24, wherein the reflection surface satisfies a condition of the following expression, wherein Rm denotes a radius of curvature in the meridional plane, Rs denotes a radius of curvature in the sagittal plane, n denotes a refractive index of a medium of the reflector, and L denotes a diameter in a direction of the first optical axis of the concave portion: sin - 1 ⁡ ( - L 2 · Rm ) + π 4 > sin - 1 ⁡ ( 1 n ) tan - 1 ( L 4 ⁢ Rs 2 - L 2 ) = - sin - 1 ⁡ ( - L 2 · Rm ) . ### Claim 26 (depends on 22) An optical instrument comprising: an objective lens; the reticle unit according to claim 22, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light exited from the reflection surface of the reticle unit are placed on top of each other. ### Claim 27 (depends on 22) A rifle scope comprising: an objective lens; the reticle unit according to claim 22, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light emitted from the reflection surface of the reticle unit are placed on top of each other. ### Claim 28 A reticle unit comprising: a reflector provided with a concave portion on one of surfaces of a plate-like optical member, wherein at least part of a side surface of the concave portion is a reflection surface; a light source that is arranged laterally to the reflector and that emits light; and a light collector that is arranged between the light source and the reflector and that collects the light from the light source onto a surface substantially parallel to the surface on which at least the concave portion is formed to form an image of the light source on or near the reflect ion surface, wherein at least part of the light incident on the reflection surface is totally reflected by the reflection surface and the totally reflected light is exited from the reflector, wherein an optical axis of the light source and the light collector is defined as a first optical axis, and an optical axis for reflecting the light by the reflection surface to exit the light from the reflector is define as a second optical axis, and wherein the reflection surface is a cylindrical surface in which only a meridional plane, which includes the first optical axis and the second optical axis, has a curvature, and an intersection of the meridional plane and a sagittal plane, which includes the optical axis of the reflection surface and which is perpendicular to the meridional plane, is tilted substantially 45° relative to the second optical axis. ### Claim 29 (depends on 28) The reticle unit according to claim 28, wherein the first optical axis and the second optical axis are substantially orthogonal. ### Claim 30 (depends on 28) The reticle unit according to claim 28, wherein the light collector is a condenser lens that collects the light from the light source in a surface orthogonal to a second optical axis and that converts the light from the light source to substantially parallel light in a surface including a first optical axis and the second optical axis, and the reflection surface is a curved surface convex toward the light source. ### Claim 31 (depends on 28) The reticle unit according to claim 28, wherein the reflection surface satisfies a condition of the following expression, wherein Rm denotes a radius of curvature in the meridional plane, n denotes a refractive index of a medium of the reflector, and L denotes a diameter in a direction of the first optical axis of the concave portion: sin - 1 ⁡ ( - L 2 · Rm ) + π 4 > sin - 1 ⁡ ( 1 n ) . ### Claim 32 (depends on 28) An optical instrument comprising: an objective lens; the reticle unit according to claim 28, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light exited from the reflection surface of the reticle unit are placed on top of each other. ### Claim 33 (depends on 28) A rifle scope comprising: an objective lens; the reticle unit according to claim 28, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light emitted from the reflection surface of the reticle unit are placed on top of each other. ### Claim 34 A reticle unit comprising: a reflector provided with a concave portion on one of surfaces of a plate-like optical member, wherein at least part of a side surface of the con cave portion is a reflection surface; a light source that is arranged laterally to the reflector and that emits light; and a light collector that is arranged between the light source and the reflector and that collects the light from the light source onto a surface substantially parallel to the surface on which at least the concave portion is formed to form an image of the light source on or near the reflection surface, wherein at least part of the light incident on the reflection surface is totally reflected by the reflection surface and the totally reflected light is exited from the reflector, and wherein a diameter when the reflection surface is projected to the side surface provided with the concave portion forming the reflection surface is within a range of 10 μm to 200 μm. ### Claim 35 (depends on 34) An optical instrument comprising: an objective lens; the reticle unit according to claim 34, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light exited from the reflection surface of the reticle unit are placed on top of each other. ### Claim 36 (depends on 34) A rifle scope comprising: an objective lens; the reticle unit according to claim 34, wherein the reflection surface is arranged at a position of an image formed by the objective lens or at a position substantially conjugate to the image; and an eyepiece for observation, wherein the image of the objective lens and the light emitted from the reflection surface of the reticle unit are placed on top of each other.