An optoelectronic sensor for detecting objects in a monitored zone is provided, wherein the sensor has a scanning unit that is movable about an axis of rotation and that has a plurality of scanning modules accommodated therein for a periodic scanning of the monitored zone and for a generation of corresponding received signals and that has a control and evaluation unit for acquiring information on the objects from the received signals; and wherein the scanning modules each comprise a light transmitter for transmitting a light beam and a light receiver for generating a respective received signal from the light beam remitted by the objects. A respective mirror element is here associated with the scanning modules to set an angle of elevation of a respective scanning plane detected by a scanning module with respect to a central scanning plane perpendicular to the axis of rotation.

A laser radar device includes a laser radar optical system that emits laser light and receives reflected light of the laser light reflected from a reflector disposed outside the laser radar device. A controller determines that it is rainy weather when a measurement width of the reflector in a scanning direction of the laser light measured by use of the laser light and the reflected light is larger than a predetermined reference measurement width of the reflector.

A laser radar device includes a laser radar optical system that emits laser light and receives reflected light of the laser light reflected from a reflector disposed outside the laser radar device. A controller determines that it is rainy weather when a measurement width of the reflector in a scanning direction of the laser light measured by use of the laser light and the reflected light is larger than a predetermined reference measurement width of the reflector.

An object detector including a light-emitting system to emit light to an object, a light detector, a signal detector, and a threshold adjuster. The light detector receives the light emitted from the light-emitting system and reflected by the object, and output a signal. The signal detector detects the signal output from the light detector based on a threshold value of voltage. The threshold adjuster changes the threshold value between when the light-emitting system emits light to a part of a light-emission range of the light-emitting system and when the light-emitting system emits light to other part of the light-emission range other than the part of the light-emission range.

An object detector including a light-emitting system to emit light to an object, a light detector, a signal detector, and a threshold adjuster. The light detector receives the light emitted from the light-emitting system and reflected by the object, and output a signal. The signal detector detects the signal output from the light detector based on a threshold value of voltage. The threshold adjuster changes the threshold value between when the light-emitting system emits light to a part of a light-emission range of the light-emitting system and when the light-emitting system emits light to other part of the light-emission range other than the part of the light-emission range.

A water purifier or other liquid dispenser may sense a height of the inlet of a container accurately through an infrared transmitter and an infrared receiver that are disposed at different positions of a water discharge module moving vertically. Additionally, in the water purifier, the water discharge module may discharge purified water at a point spaced a certain distance apart from the inlet of the container, based on infrared sensing, thereby preventing the inlet of the container from contacting the lower surface of the water discharge module.

A water purifier or other liquid dispenser may sense a height of the inlet of a container accurately through an infrared transmitter and an infrared receiver that are disposed at different positions of a water discharge module moving vertically. Additionally, in the water purifier, the water discharge module may discharge purified water at a point spaced a certain distance apart from the inlet of the container, based on infrared sensing, thereby preventing the inlet of the container from contacting the lower surface of the water discharge module.

A high resolution inspection apparatus using a terahertz Bessel beam. The high resolution inspection apparatus comprises a terahertz wave generating unit for generating a terahertz wave; a Bessel beam forming unit for generating a terahertz Bessel beam using the terahertz wave incident from the terahertz wave generating unit; a ring beam forming unit for forming a ring beam using the terahertz Bessel beam and concentrating the formed ring beam to an inspection target object; a scattered light detecting unit for detecting scattered light generated from the inspection target object; and a ring beam detecting unit for detecting a ring beam transmitted through the inspection target object.

A high resolution inspection apparatus using a terahertz Bessel beam. The high resolution inspection apparatus comprises a terahertz wave generating unit for generating a terahertz wave; a Bessel beam forming unit for generating a terahertz Bessel beam using the terahertz wave incident from the terahertz wave generating unit; a ring beam forming unit for forming a ring beam using the terahertz Bessel beam and concentrating the formed ring beam to an inspection target object; a scattered light detecting unit for detecting scattered light generated from the inspection target object; and a ring beam detecting unit for detecting a ring beam transmitted through the inspection target object.

Provided is an object detection system including: a ranging device that emits light so as to pass through a detection region and receives reflected light in which the ranging device is configured to perform a scan by changing an optical path of emitted light; and a reflection member that is provided in a scan range so as to reflect light passing through the detection region toward the ranging device.