A projection lens is separated into a first optical system that is disposed so as to be closer to an image forming panel and a second optical system that includes a mirror and is disposed so as to be closer to a screen which is a projection surface by the second mirror. The second optical system is set in a first position and a second position by inverting the second optical system around a second optical axis with respect to the first optical system by 180 by an inverting unit. An orientation of a projected image onto the screen is set in the first position and the second position by inverting the image displayed on the image forming panel according to the first position and the second position. It is possible to achieve projection for positioning a center of the screen above or under the optical axis by switching between the first position and the second position.

A projection lens is separated by a second mirror into a first optical system that is disposed so as to be closer to an image forming panel and a second optical system that includes the second mirror and is disposed so as to be closer to a screen which is a projection surface. The second optical system is held rotatably around a second optical axis with respect to the first optical system by a first rotation mechanism. A rotation angle of the second optical system with respect to the first optical system is detected by a first sensor. A tilt angle of the projected image on the projection surface by the rotation angle is obtained by a tilt correction section, and the display position of the image to be displayed on the image forming panel is corrected according to the tilt angle.

A firearm sight assembly comprises a rear base. The firearm sight assembly comprises a rear sight element movable with respect to the rear base between a lowered condition and an elevated condition. The rear sight element has a first pair of upwardly projecting first rear posts defining a first notch therebetween when in the lowered condition. The rear sight element has a second pair of upwardly projecting second rear posts defining a second notch therebetween when in the elevated condition. The first rear posts extend to a first height above the rear base, and the second rear posts extend to a second height above the rear base. The second height is greater than the first height.

A firearm sight assembly comprises a rear base. The firearm sight assembly comprises a rear sight element movable with respect to the rear base between a lowered condition and an elevated condition. The rear sight element has a first pair of upwardly projecting first rear posts defining a first notch therebetween when in the lowered condition. The rear sight element has a second pair of upwardly projecting second rear posts defining a second notch therebetween when in the elevated condition. The first rear posts extend to a first height above the rear base, and the second rear posts extend to a second height above the rear base. The second height is greater than the first height.

Described herein is an apparatus, for shielding light generated by a laser during non-destructive inspection of an object. The apparatus includes a light shield at least partially enveloping the laser and defining a first opening through which light generated by the laser passes from the laser to the object. The light shield is opaque and includes at least one first biasing mechanism. The apparatus also includes at least one first light seal coupled to the light shield about the first opening of the light shield. The at least one first biasing mechanism is configured to urge resilient deformation of the at least one first light seal against the object. When the at least one first light seal is resiliently deformed against the object, light generated by the laser is constrained within a light containment space defined between the light shield, the at least one first light seal, and the object.

Described herein is an apparatus, for shielding light generated by a laser during non-destructive inspection of an object. The apparatus includes a light shield at least partially enveloping the laser and defining a first opening through which light generated by the laser passes from the laser to the object. The light shield is opaque and includes at least one first biasing mechanism. The apparatus also includes at least one first light seal coupled to the light shield about the first opening of the light shield. The at least one first biasing mechanism is configured to urge resilient deformation of the at least one first light seal against the object. When the at least one first light seal is resiliently deformed against the object, light generated by the laser is constrained within a light containment space defined between the light shield, the at least one first light seal, and the object.

Fabry-Perot based optical computing devices and temperature sensors are disclosed for a number of applications including, for example, in-situ downhole fluid analysis and temperature detection.

Described herein is an apparatus, for shielding light generated by a laser during non-destructive inspection of an object. The apparatus includes a light shield at least partially enveloping the laser and defining a first opening through which light generated by the laser passes from the laser to the object. The light shield is opaque and includes at least one first biasing mechanism. The apparatus also includes at least one first light seal coupled to the light shield about the first opening of the light shield. The at least one first biasing mechanism is configured to urge resilient deformation of the at least one first light seal against the object. When the at least one first light seal is resiliently deformed against the object, light generated by the laser is constrained within a light containment space defined between the light shield, the at least one first light seal, and the object.

Described herein is an apparatus, for shielding light generated by a laser during non-destructive inspection of an object. The apparatus includes a light shield at least partially enveloping the laser and defining a first opening through which light generated by the laser passes from the laser to the object. The light shield is opaque and includes at least one first biasing mechanism. The apparatus also includes at least one first light seal coupled to the light shield about the first opening of the light shield. The at least one first biasing mechanism is configured to urge resilient deformation of the at least one first light seal against the object. When the at least one first light seal is resiliently deformed against the object, light generated by the laser is constrained within a light containment space defined between the light shield, the at least one first light seal, and the object.

Systems for communication in a rotary joint. In one example, a communication system includes a stator, a rotor, a plurality of optical receivers circumferentially disposed at a first radius of one of the stator and the rotor, a plurality of optical transmitters circumferentially disposed at a second radius of the other of the stator and the rotor, each optical transmitter of the plurality configured to transmit a data signal to a corresponding optical receiver of the plurality of optical receivers, and a plurality of optical elements, individual optical elements having one of a first size and a second size, wherein individual optical elements are interposed between each optical transmitter of the plurality of optical transmitters and each optical receiver of the plurality of optical receivers and arranged so as to alternate between the first size and the second size along one of the first radius and the second radius.