A catadioptric optical system in sequence of ray tracing comprises a first mirrors group of Ritchey-Chrétien type hyperbolic mirrors with positive diopter including a concave primary mirror having a central through hole and a convex secondary mirror, a second corrector lens group with negative diopter positioned at the image-side of the first mirrors group including a first meniscus lens element having positive refractive power and a convex object-side surface, a second lens element having negative refractive power and biconcave surfaces, a third meniscus lens element having negative refractive power and a concave object-side surface, and a fourth lens element having positive refractive power and biconvex surfaces. The infinite conjugate beams of incident light within field of view pass through the catadioptric optical system to become a corrected beam having a small CRA angle.

A first light guide guides first light in a first light guiding path. The first light is of light irradiated from the light source to a sheet. A first detection unit receives reflected light from the sheet and outputs an image signal indicating an image of a surface of the sheet. A second light guide guides second light in a second light guiding path different from the first light guiding path. The second light is of the light irradiated from the light source and is different from the first light. A second detection unit receives the second light and output a detection signal corresponding to a light amount of the second light. A control unit controls a light emission amount of the light source based on the detection signal.

An optical device provided with an optical parts position adjusting and fixing device for adjusting and fixing the position of the optical parts moving in an optical axis direction, wherein the position adjusting and fixing device is provided with a long slotted hole extended in the optical axis direction formed on a side surface of the optical parts; a fixing means which is mounted on an object to be fixed of the optical parts and which is movable along the long slotted hole; a non-penetrating screw hole formed in the fixing means and which is divided by a slit; and a screw which is screwed into the screw hole and spreads the slit when screwed into the screw hole so as to press the outer surface of the fixing means against the inner surface of the long slotted hole.

A first light guide guides first light in a first light guiding path. The first light is of light irradiated from the light source to a sheet. A first detection unit receives reflected light from the sheet and outputs an image signal indicating an image of a surface of the sheet. A second light guide guides second light in a second light guiding path different from the first light guiding path. The second light is of the light irradiated from the light source and is different from the first light. A second detection unit receives the second light and output a detection signal corresponding to a light amount of the second light. A control unit controls a light emission amount of the light source based on the detection signal.

The disclosure relates to multifunctional sensors for mobile applications, namely to a miniature optical sensor for remote micro- and macro-object detection and characterization. The disclosure makes it possible to reduce the size of the sensor, this provides for surface mount of the sensor in any microcircuit of a mobile device. The sensor is multifunctional, low-power, vibration-resistant. The sensor comprises at least one pair consisting of a radiation source and a corresponding radiation receiver, an optical circuit including a collimating element, a first optical element, a second optical element. The first optical element and the second optical element are interconnected by a common surface, the common surface being a semitransparent surface. The sensor may be used simultaneously as a microphone, a dust sensor, a lidar, and a photoplethysmogram (PPG) sensor.

A first light guide guides first light in a first light guiding path. The first light is of light irradiated from the light source to a sheet. A first detection unit receives reflected light from the sheet and outputs an image signal indicating an image of a surface of the sheet. A second light guide guides second light in a second light guiding path different from the first light guiding path. The second light is of the light irradiated from the light source and is different from the first light. A second detection unit receives the second light and output a detection signal corresponding to a light amount of the second light. A control unit controls a light emission amount of the light source based on the detection signal.

The disclosure relates to multifunctional sensors for mobile applications, namely to a miniature optical sensor for remote micro- and macro-object detection and characterization. The disclosure makes it possible to reduce the size of the sensor, this provides for surface mount of the sensor in any microcircuit of a mobile device. The sensor is multifunctional, low-power, vibration-resistant. The sensor comprises at least one pair consisting of a radiation source and a corresponding radiation receiver, an optical circuit including a collimating element, a first optical element, a second optical element. The first optical element and the second optical element are interconnected by a common surface, the common surface being a semitransparent surface. The sensor may be used simultaneously as a microphone, a dust sensor, a lidar, and a photoplethysmogram (PPG) sensor.

A catadioptric optical system in sequence of ray tracing comprises a first mirrors group of Ritchey-Chrtien type hyperbolic mirrors with positive diopter including a concave primary mirror having a central through hole and a convex secondary mirror, a second corrector lens group with negative diopter positioned at the image-side of the first mirrors group including a first meniscus lens element having positive refractive power and a convex object-side surface, a second lens element having negative refractive power and biconcave surfaces, a third meniscus lens element having negative refractive power and a concave object-side surface, and a fourth lens element having positive refractive power and biconvex surfaces. The infinite conjugate beams of incident light within field of view pass through the catadioptric optical system to become a corrected beam having a small CRA angle.

An optical system for light distribution. The optical system includes at least a reflective surface, at least two refracting surfaces, at least one inner lens and an outer lens. The optical system provides high efficiency collection and distribution of light.

A first light guide guides first light in a first light guiding path. The first light is of light irradiated from the light source to a sheet. A first detection unit receives reflected light from the sheet and outputs an image signal indicating an image of a surface of the sheet. A second light guide guides second light in a second light guiding path different from the first light guiding path. The second light is of the light irradiated from the light source and is different from the first light. A second detection unit receives the second light and output a detection signal corresponding to a light amount of the second light. A control unit controls a light emission amount of the light source based on the detection signal.