Abstract: Binoculars and an ocular lens have an excellent optical performance. Binoculars include: a first lens-barrel and a second lens-barrel having an objective lens and an ocular lens; and an Abbe-Koenig prism which is an erecting optical element included in the first lens-barrel and the second lens-barrel, and is characterized in that the product of an effective diameter (mm) of the objective lens and the real field of view (°) is 450 mm° or larger.

Abstract: A variable-power optical system includes, in order from an object, an objective optical system (O), a relay optical system (R), and an eyepiece optical system (E), wherein the relay optical system is provided with, in order from the object, a first lens group (G1) having positive refractive power, a second lens group (G2) having positive refractive power, and a third lens group (G3) having positive refractive power, and is an optical system in which an image formed by the objective optical system with variable optical power, and the variable-power optical system is configured so as to satisfy expressions: 0.7<|?|min<1.4, and 12 (mm)<fmin<15 (mm), where |?|min denotes a minimum of absolute value of imaging magnification of the relay optical system, and fmin denotes a shortest focal length.

Abstract: A distance measuring apparatus includes: a light-transmitting unit that transmits signal light from a light source toward a target object; a light-receiving unit that has a light-receiving element and receives the signal light from the target object on an optical axis different from that of the light-transmitting unit; a distance measuring unit that measures a distance to the target object based on propagation time from light transmission to light reception of the signal light; and a compensating unit that, while either optical path of an optical path from the light-transmitting unit to the light-receiving unit or an optical path from the target object to the light-receiving element is fixed, compensates an optical path of the signal light by displacing the other optical path at the light-transmitting unit or the light-receiving unit.

Abstract: Interpupillary distance of binoculars is adjusted by relatively rotating a pair of lens barrels about a predetermined axis. A click position setting mechanism sets a click position at an arbitrary angle of rotation of said pair of lens barrels and includes a rotating member rotatable about the predetermined axis. A lock/unlock member locks and unlocks the rotation of the rotating member.

Abstract: An anti-vibration optical system is an observation optical system including, in sequence from an object side, an objective optical system, an erecting prism, and an ocular optical system, wherein: in sequence from the object side, the objective optical system includes a first lens group having a positive refracting power and a second lens group having a negative refracting power; in sequence from the object side, the second lens group comprises a positive lens group having a positive refracting power and a negative lens group having a negative refracting power; and an image position can be changed by the negative lens group of the second lens group being displaced in a direction orthogonal to an optical axis.

Abstract: A distance detection apparatus including: a light output unit which outputs a light; a computation unit which computes a distance to a detection target by using a time until when the light output from the light output unit is received in a light receiving unit; a deblurring optical system which is driven based on a detection result of a blurring and through which the output light is transmitted; a detection unit which detects a position of the deblurring optical system; a storage unit which stores a predetermined range; a determination unit which determines whether the position detected by the detection unit is included in the predetermined range; and a control unit which controls a light output by the light output unit in accordance with a determination result of the determination unit.

Abstract: A distance detection apparatus includes: a detection unit which detects a time until when an output light is received by a light receiving unit; a computation unit which computes a distance to a detection target by using the time detected by the detection unit; an obtaining unit which obtains a predetermined range which is a range prone to a detection error due to a fog; and a determination unit which determines whether the distance to the detection target computed by the computation unit is included in the predetermined range.

Abstract: A reticle unit equipped with an optical apparatus such as a riflescope includes: red and green light sources radiating red light and green light; a disc-like shaped reticle substrate that has a diffraction grating formed at substantially the center of a surface having substantially circular shape; and red and green mirror members converge light radiated from the red and green light sources, make incidence on the reticle substrate from corresponding side surface portions of the reticle substrate to illuminate the diffraction grating so as to emit first order diffracted light reflected and diffracted by the diffraction grating along a normal direction of the diffraction grating.

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.

Abstract: A distance detection apparatus includes: a detection unit which detects a time until when an output light is received by a light receiving unit; a computation unit which computes a distance to a detection target by using the time detected by the detection unit; an obtaining unit which obtains a predetermined range which is a range prone to a detection error due to a fog; and a determination unit which determines whether the distance to the detection target computed by the computation unit is included in the predetermined range.