Abstract: An optical position detection device that detects a position of a target object, includes plural detection light sources that output detection light, alight source drive unit that drives the plural detection light sources, a first light receiving unit that receives the detection light reflected by the target object located in an output space of the detection light, a compensation light source unit that outputs compensation light that enters outside the output space, a second light receiving unit that receives the compensation light, and a position detection unit that detects the position of the target object based on a difference between first received light intensity in the first light receiving unit and second received light intensity in the second light receiving unit.

Abstract: A reflective optical detecting device is for detecting movement of an object in a predetermined area. The reflective optical detecting device includes a light emitting unit, at least two optical detectors, and a comparing unit. The light emitting unit is used for illuminating the predetermined area. The optical detectors are disposed at opposite sides of the light emitting unit, and each of the optical detectors is associated with a respective detection region within the predetermined area for generating an output signal in response to light reflected from the object and detected thereby. The comparing unit is coupled to the optical detectors for receiving the output signal from each of the optical detectors, and is operable to output a comparison result according to the output signal of each of the optical detectors. The comparison result is to be used for determining the movement of the object.

Abstract: According to one embodiment, a coordinate recognizing apparatus includes plural light emitting elements, plural light receiving elements, a memory, and a controller. The memory stores, concerning plural pairs of the light emitting elements and the light receiving elements set in advance, reference values used for determination of blocking of a light path. The controller performs, concerning the respective pairs, actions for collecting, plural times, a difference between first intensity indicated by a detection signal output from the light receiving element, which is a pair of the light emitting element, in a state in which the light emitting element is caused to emit light and second intensity indicated by a detection signal output from the light receiving element during non-light emission of the light emitting element and updating the reference value of the pair stored in the memory using a minimum of differences collected plural times.

Abstract: A sun-locating apparatus includes a substrate, a mounting unit, a photo-detecting unit, an optical element and a cover. The mounting unit is provided on the substrate and formed with an upper aperture and a lower aperture in communication with the upper aperture. The photo-detecting unit is located in the lower aperture. The photo-detecting unit includes at least four photodiodes. The optical element is provided on the mounting unit for covering the upper aperture. The cover is provided on the substrate for covering the mounting unit, the photo-detecting unit and the optical element.

Abstract: There is provided a position detecting device using reflection type photosensors in which a position sensing of lens located not less than 1 mm apart from a sensor can be conducted. A pair of reflection type photosensors PR1 and PR2 are oppositely arranged, a double sided reflector 5 attached on a movable body is movably arranged between the pair of reflection type photosensors and a position of the double sided reflector 5 is detected from the outputs of these reflection type photosensors. In the position detecting device of the present invention, an operating formula in which linear values are obtained depending on a moving distance of the double sided reflector can be used. For example, when an output of one of the pair of reflection type photosensors is Vo1, and an output of the other is Vo2, the position detecting is conducted using the operating formula of (Vo1?Vo2)/(Vo1+Vo2).

Abstract: A light source detection device includes first photo sensors disposed on a reference plane along a first direction and a control unit. Each first photo sensor has a first sensing surface for detecting a photo intensity of a light source to output a photo intensity signal. The first sensing surfaces are back to back or face to face. An included angle between a normal vector of one of the first sensing surfaces and a normal vector of the reference plane is equal to an included angle between a normal vector of another one of the first sensing surfaces and the normal vector of the reference plane. The normal vectors are coplanar. The control unit is adapted to receive the photo intensity signals and normalize the difference of the photo intensities of the light source sensed by the first photo sensors, so as to detect a position of the light source.

Abstract: Foreign substance information about at last including a position of a foreign substance adhered to an optical element disposed in front of an image sensor is detected, and whether the position of the foreign substance overlaps a predetermined area of an object is determined by analyzing an image signal of the object generated by the image sensor. When it is determined that the position of the foreign substance overlaps the predetermined area of the object, a relative position of the image of the object formed on the image sensor and the image sensor is changed.

Abstract: A tilt sensor with power-saving mechanism is provided. The tilt sensor includes a light-emitting element, a blocking object displaceable in an accommodating space on a baseboard, at least two first light sensors, a second light sensor and a control module. The first and the second light sensors respectively sense a light amount and a light amount variation according to the relative position of the light-emitting element and the blocking object. During a power-saving mode, when the light amount variation is larger than a specific value, the control module makes the light-emitting element work in a working mode to emit light according to a first current. During the work mode, when the light amount does not change or the light amount variation is smaller than a threshold value, the control module makes the light-emitting element work in the power-saving mode to emit light according to a second current.

Abstract: A solar tracking device for solar panel includes a barrel body, a light transmitting unit, a projecting unit, a photosensor unit, and a lens. The light transmitting unit is disposed at a first end of the barrel body oriented toward the sun. The light transmitting unit has a light-transmittable crossing point provided at a center thereof. The projecting unit is an opaque member arranged between the first end and a second end of the barrel body. The photosensor unit is arranged to one side of the projecting unit, so that the projecting unit is located between the light transmitting unit and the photosensor unit. The photosensor unit has a locating center preset at a center of the projecting unit. The lens is arranged between the projecting unit and the photosensor unit. The barrel body is a telescopic barrel enabling the solar tracking device to switch between different operating angle modes.

Abstract: A safety device for a machine, such as a press brake, has a light transmitter, a light receiver and an evaluation unit. The light receiver is coupled to a moving machine part such that it runs ahead of a front edge of the machine part during the operational movement. The light transmitter comprises a light source having a predominantly incoherent radiation for generating a light beam that runs substantially parallel to the edge and illuminates the light receiver. The light receiver has an image sensor with a plurality of pixels for recording a spatially resolved image of the light beam, and it has an imaging optics having a focal point and an aperture stop which is substantially arranged at the focal point.

Abstract: A light collecting optical fiber improves light injection efficiency into the optical fiber. The light collecting optical fiber is equipped with a plurality of optical waveguide portions and light collecting portions between the adjacent optical waveguides. The optical waveguide portion includes a core and a cladding layer surrounding the core and constitutes an optical fiber. The light collecting portion is formed in a shape bulging out in radial direction from the optical waveguide portion and is constituted so that it injects external light to the optical waveguide portion.

Abstract: A system for imaging an object comprising a surface for receiving the object to be imaged and an imaging device. The imaging device comprises a housing and a fixed focusing optical device mounted to the housing, whereby the fixed focusing optics comprises a lens for focusing light reflected from the object. A plurality of independent linear imaging sensors are positioned in the housing at different distances from the fixed focusing lens so that a face of each of the plurality of independent linear imaging sensors is aligned parallel to the surface. A processor is coupled to the plurality of independent linear imaging sensors for receiving an output signal from each of the plurality of independent linear imaging sensors representative of the reflected light. The lens defines a plane parallel to the surface, and the plurality of independent linear imaging sensors are adapted to receive reflected light from the object.

Abstract: An optical position detecting device includes: a plurality of detection light source sections which includes a first light emitting element which emits a first detection light and a second light emitting element which is turned on at a timing different from a timing when the first light emitting element is turned on and emits a second detection light having a peak wavelength different from that of the first detection light; a light source driving section which turns on a part of the plurality of detection light source sections, and turns on the other part thereof; a light detecting section which detects the first detection light and the second detection light reflected by a object; and a position detecting section which detects the position of the object on the basis of the intensity of the first detection light and the intensity of the second detection light in the light detecting section.

Abstract: A beam irradiation apparatus includes: an actuator which scans a target region with a laser beam; a photodetector which receives a servo beam and outputs a signal according to a beam reception position; an optical unit which makes the servo beam displaced on the photodetector in association with driving of the actuator; and a position signal generation circuit that generates a signal according to the reception position of the servo beam based on an output signal from the photodetector. The position signal generation circuit has a signal removal circuit that removes a disturbance signal generated when the laser beam is incident on the photodetector, from an output signal of the photodetector.

Abstract: This invention provides a light scanning photoelectric switch with which various settings of the light scanning photoelectric switch such as setting of a protection area can be easily set. The light scanning photoelectric switch includes: a display unit having a display screen that displays information including at least one of a status of a safety function of the light scanning photoelectric switch, and information of a failure status; and an operating unit provided in vicinity of the display unit, and for switching the information displayed in the display screen to different one of the safety signal, the result of the determination, setting contents of the light scanning photoelectric switch, the status of the safety function of the light scanning photoelectric switch, and the information of the failure status.

Abstract: An optical position detection device includes a first detection light source unit that outputs a detection light from one side to the other side in a first direction, a second detection light source unit that is separated from the first detection light source unit along a second direction crossing the first direction, and outputs a detection light from the one side to the other side in the first direction, a light detection unit having sensitivity toward the other side in the first direction, and a position detection unit that detects the position of the object based on the light reception in the light detection unit.

Abstract: In an apparatus with a position detection function, a position detecting section detects the position of a target object on the basis of a result obtained by receiving detection light, which is emitted from a light source section for detection and reflected by the target object, using a light detection section. As seen from an emitting direction of the detection light, the light detection section is located inside a region surrounded by a closed circuit passing through a plurality of the light source sections for detection or inside a region pinched by the plurality of light source sections for detection. The plurality of light source sections for detection has a first light-emitting element, and a second light-emitting element located closer to the light detection section side than the first light-emitting element. The light source driving section alternately turns on the first light-emitting element and the second light-emitting element.

Abstract: A touch panel includes: a substrate; a plurality of light emitting elements; and a plurality of light receiving elements, wherein the number of light receiving elements may be greater than the number of light emitting elements.

Abstract: A level sensor, i.e., a light receiving section (11X) having multiple light receiving elements (PDX1 to PDXn) arranged in parallel. In the level sensor, each two adjacent output terminals of the light receiving elements (PDX1 to PDXn) are connected by one of resistors (RX1 to RXn).

Abstract: The calculation device (36) according to the present invention receives a plurality of reflected light intensity information for indicating the intensity of each reflected light which reaches a single light receiver via a reflecting object, the reflected light having been emitted in sequence from a plurality of light emitters (31 through 33) provided in mutually different positions, computes a phase difference of an intensity variation which occurs among the reflected light, and determines a movement of the reflecting object on the basis of the calculation result.

Abstract: A solar sensor for the detection of the direction of incidence and the intensity of solar radiation comprises a housing (12) made of a plastic material that is permeable to at least some of the solar radiation, the housing (12) having a curved side (14) facing the incident solar radiation and the housing (12) optically acting as a lens and having an internal focal plane (26) defined by the lens characteristics thereof. At least two photosensors (16) are embedded in the plastic material of the housing (12), each photosensor (16) having a sensor area (18) sensitive to at least the part of the radiation to which the plastic material is permeable, and the sensor areas (18) of the photosensors (16) being arranged in a substantially common plane (19) located in front of or behind the focal plane (26), seen from side (14) facing the incident solar radiation.

Abstract: An electronic device includes a processing unit, a first sensor, and a second sensor. The first and the second sensors are configured to generate signals if an object is within their detection zone. The processing unit is configured to receive the signals from the first sensor and the second sensor, and determine whether to lock or unlock the electronic device according to a sequence of the signals it receives from the first sensor and the second sensor within a predetermined time period.

Abstract: A position detection system can utilize multiple optical responses to a detection scene, such as by using multiple different patterns of light for imaging a given detection scene. The multiple patterns can include a first pattern containing image data that can be used to separate reflected light from retroreflected light in a second pattern of light. This can be used to reduce errors, such as false detections due to directly-reflected light, and/or can be used for identification of objects in the touch detection scene when the objects themselves are optically configured to appear differently in different patterns of light.

Abstract: The present invention includes an apparatus for watertight sealing of a steam generator nozzle and methods for installing the apparatus. The apparatus comprises a nozzle dam, a nozzle dam attachment ring, and a seal. The attachment ring is provided in an interior of the nozzle and has a plurality of retaining tabs and a nozzle dam landing. The nozzle dam is adapted for insertion into the attachment ring and abutment against the nozzle dam landing. The nozzle dam has a plurality of radial protrusions adapted to interlock with the retaining tabs for fixing the nozzle dam in the attachment ring upon rotation of the nozzle dam in the attachment ring. The seal covers at least one side of the nozzle dam for effecting a seal between the nozzle dam and the attachment ring. The present invention also provides methods and apparatus for the pressurization and control of nozzle dam seals.

Abstract: An method and system for laser beam tracking and pointing is based on a conventional position sensing detector (PSD) or quadrant cell but with the use of amplitude-modulated light. A combination of logarithmic automatic gain control, filtering, and synchronous detection offers high angular precision with exceptional dynamic range and sensitivity, while maintaining wide bandwidth. Use of modulated light enables the tracking of multiple beams simultaneously through the use of different modulation frequencies. It also makes the system resistant to interfering light sources such as ambient light. Beam pointing is accomplished by feeding back errors in the measured beam position to a beam steering element, such as a steering mirror. Closed-loop tracking performance is superior to existing methods, especially under conditions of atmospheric scintillation.

Abstract: A system, method, and computer program product are provided for determining the location of a mobile object moving beneath an aerial vehicle. In operation, a mobile object is sensed utilizing one or more sensors coupled to an aerial vehicle. Additionally, an object signature for the mobile object is generated utilizing signals received from the one or more sensors. Furthermore, the mobile object is tracked utilizing the object signature.

Abstract: A detection sensor to detect a receiving position of laser light according to the present invention includes a pair of light receiving element arrays (11X and 11Y), wherein adjacent light receiving elements (PDXi) are positioned as spaced equidistantly from one another and are mutually connected via a resistor (RXj), and wherein the output lines (11a and 11b) are respectively connected to the light receiving elements that are present at both ends of the respective light receiving element arrays (11X and 11Y). The light receiving element arrays (11X and 11Y) configure a composite array wherein the light receiving elements of a first light receiving element array are respectively positioned between the mutually adjacent light receiving elements of a second light receiving element array.

Abstract: Methods and apparatus are provided for a control device and control device operation. In one embodiment a control device includes a slider configured to support a control knob, a rack coupled to the slider and configured to linearly displace the slider. The rack including slots. The control device may further include a drive element configured to displace the rack and position the control knob, and an optical detection module configured to detect position of the control knob based on one or more optical signals detected relative to slots of the rack. According to another embodiment, a control console is provided including control devices.

Abstract: A rotor type orientation sensor includes a housing, a plurality of light emitters, two light receivers and a rotor. The housing has a circular tunnel and a plurality of first openings connecting to the tunnel and two second openings located on two sides of the first openings. The light emitters emit light into the tunnel through the first openings. The light receivers receive light from the tunnel through the second openings. The rotor is arranged in the tunnel, whereby while the rotor type orientation sensor is tilting, the rotor rotates toward the direction of gravity force, at least a portion of light emitted from the light emitters is blocked by the rotor, one of the light receivers is blocked by the rotor, the light receivers can respectively receive light with predetermined intensity and correspondingly output electric signals with predetermined strength.

Abstract: In a pattern-defect inspection method for inspecting a defect in an inspection pattern by comparing an image of the inspection pattern with an image of a reference pattern, inspection sensitivity is adjusted in accordance with the number of corner portion and so on of the reference pattern.

Abstract: An encoder having an oil mist prevention structure includes: an encoding body including a cylindrical base, a light emitter and a secondary encoding piece; an oil-containing bearing received and fixed in the cylindrical base; a shaft penetrating the oil-containing bearing to protrude beyond an end surface of the bearing; a rotary disk fixed onto the shaft to cover one side of the secondary encoding piece; a light acceptor fixed to the cylindrical base to correspond to the light emitter and the secondary encoding piece, thereby receiving the signals emitted by the light emitter; and an oil mist prevention structure including a mask integrally formed with the shaft and exposed beyond an end surface of the bearing and a ring extending from the mask for covering an outer periphery of the bearing.

Abstract: A portable housing of a moving laser beam reader or an imaging reader is held by an operator in a handheld mode during electro-optical reading of symbols. A docking station supports the housing in a docked state when the housing is not in the handheld mode. At least one proximity sensor is supported by the housing and/or the docking station. The proximity sensor detects the operator's remoteness from the sensor to lock the housing to the docking station in the docked state, and detects the operator's proximity to the sensor to release the housing from the docking station.

Abstract: A laser light receiver used to detect pulsed laser light that is produced by a rotating laser light source on a construction jobsite is disclosed. In this manner, the laser receiver acts as an elevation detector and provides an equipment operator, or a construction worker, with the current elevation status with respect to the plane of laser light. The laser receiver is a unitary device that can detect multiple light frequencies/wavelengths, including laser beams that are in the green, red, and infrared spectra. The laser receiver also is capable of discriminating between such laser beams and other interference light sources, particularly fluorescent light sources.

Abstract: There is described portable electronic devices having one or more proximity sensors with adaptive capabilities that can help reduce power consumption. The proximity sensors of the portable electronic device in accordance with the present invention may be adjusted to operate in multiple and/or different modes. These modes are environmentally and contextually driven. An adaptive sensor is dynamically adjusted based on different criteria. In particular, adjustments are based on correlations of input signals from one or more sensors of the device, data signals received from the device's processor and/or external data signals received from an external source, which provide characterization values of environmental, contextual and/or ambient light characteristics. Adjustments are made to pulse power to affect the range of the sensor, pulse frequency, filtering of noise of the sensor input signal to attenuate interference and the spectrum of a proximity detector.

Abstract: An occupancy sensor is provided with a separable override unit which can selectively override the operation of the occupancy sensor at designated times and for selected time intervals. The occupancy sensor includes a light sensor for actuating the occupancy sensor and a light assembly when the ambient light is below a predetermined level and to deactivate the occupancy sensor when the ambient light is above a threshold level to prevent the light assembly from being actuated when the light level is sufficient to avoid the need for actuating the light assembly. The override unit is removably attached to the occupancy sensor and is provided with a light source, such as an LED. The override unit is coupled to the occupancy sensor to emit light to actuate the light sensor of the occupancy sensor, thereby controlling the operation of the occupancy sensor, such as by preventing the occupancy sensor from being actuated regardless of the light level in the surrounding areas.

Abstract: Provided herein are optical sensor systems that can be used for ambient light detection, proximity detection and motion detection, as well as to larger systems that include such an optical sensor system, and to related methods. In an embodiment, the optical sensor system includes a front end, an ambient light channel, a proximity channel and a motion channel. In an embodiment, offset and gain of the proximity channel is adjusted based on motion detected by the motion channel.

Abstract: A laser imaging system and method of projecting a laser template on a surface, including independently determining a position and orientation of the surface using an external metrology device, independently determining a position and orientation of a laser projector using the metrology device, generating a signal from the metrology device to a computer and orienting the laser projector relative to the surface to project a laser template. The apparatus includes a plurality of metrology transmitters at fixed locations, a plurality of metrology receivers at fixed locations relative to the surface and a plurality of metrology receivers at fixed locations relative to either the laser projector or laser targets within a field of view of the laser projector. A laser projector and frame assembly is also disclosed, wherein the metrology receivers are located on the frame and the frame includes laser targets for correcting laser drift.

Abstract: Disclosed is a geodetic target object comprising at least one reflector surface, a receive channel with a detector (18) for receiving electromagnetic radiation (ES) transmitted by a measuring unit (2?), and a transmit channel with a radiation source (13?). The associated transmission port and/or reception port is/are integrated into the reflector surface or is/are embodied so as to adjoin the reflector surface such that radiation (RS) that is modulated for transmitting data can be transmitted in the direction of the measuring unit (2?) within the cross section (5?) of the radiation (ES) generated by the measuring unit (2?).

Abstract: A light refracting element formed in parallel plate shape is attached to a support shaft of a mirror holder, a semiconductor laser and a PSD are disposed at positions between which the light refracting element is sandwiched. The light refracting element is rotated by rotation of the mirror holder, and whereby a laser beam irradiation position is changed on a light acceptance surface of PSD. The laser beam irradiation position on a light acceptance surface corresponds to the mirror rotation position, so that the mirror rotation position and a laser beam scanning position in a target area can be detected based on an output from the PSD.

Abstract: A beam irradiation apparatus includes: an optical element which changes a travel direction of a laser beam by being rotated in a predetermined direction; an actuator which rotates the optical element in the direction; a refractive element which is disposed in the actuator and rotates in association with rotation of the optical element; a servo beam source which emits a servo beam to the refractive element; a photodetector which receives the servo beam refracted by the refractive element and outputs a signal according to a position where the servo beam is received; and a power adjustment circuit which adjusts emission power of the servo beam source. The power adjustment circuit adjusts the emission power so that a reception amount of the servo beam in the photodetector becomes constant based on an output signal from the photodetector.

Abstract: There is provided an optical scanning type photoelectric switch capable of facilitating control of holding a set detection sensitivity, wherein first and second reflection surfaces with different reflection factors are built as reference objects in the optical scanning type photoelectric switch, and arranged in a measurement invalid range in rotation of a scanning mirror, a light projection path, a light reception path, a laser light source LD and a light receiving element, which are used for scanning in the measurement area, are shared, and when a light reception intensity of the white second reflection surface is smaller than a “reference light reception intensity (white)”, a light projection driving section is controlled to increase the light projection intensity.

Abstract: Multiple observations using a reconfigurable space-based telescope are performed by independently targeting one or more sensor units, within a field of view, relative to a main body of the space-based telescope. The sensor units are capable of simultaneously obtaining an image of one or more targets, respectively. At least one of the sensor units is independently retargetable relative to the main body of the space-based telescope to obtain an image of at least one other target. Further, the sensor units are independently maneuverable in formation relative to the main body of the space-based telescope to obtain various lines of sight without changing an optical axis of the main body of the space-based telescope.

Abstract: An encoder/sensor can obtain sensing results from objects in an encoding/sensing region; a trigger detector can respond to objects in a trigger detection region, providing respective trigger signals; and a relative motion component can cause relative motion of objects into the trigger detection region, from it into the encoding/sensing region, and within the encoding/sensing region. In response to an object's trigger signal, control circuitry can cause the encoder/sensor and/or the relative motion component to operate so that the encoder/sensor obtains sensing results indicating a time-varying waveform and processing circuitry can obtain data from the sensing results indicating a time-varying waveform. The time-varying waveform can include information resulting from the relative motion within the encoding/sensing region. The encoder/sensor and trigger detector can be implemented, for example, with discrete components or as sets of cells in a photosensing array on an integrated circuit.

Abstract: An algorithmic method is described for sensor-based real-time application of an agricultural material. Method includes means for characterizing and treating crop biomass variability without the use of a grower managed reference crop. Crop variability is determined statistically by driving one or more transects through the field in order to collect crop canopy information for sensor calibration purposes.

Abstract: A photodetector arrangement has a semiconductor body with a substrate, and first, second and third layers. The first layer is located at the first main surface of the semiconductor body which is suited for reception of incident photon radiation which is to be detected. The second layer is located at the second main surface of the semiconductor body which is at a distance to the first main surface. The third layer is located between the substrate and the second layer.

Abstract: A spatial information detection system, which is capable of, even when detecting spatial information from a common target space by use of a plurality of detection devices, achieving accurate detection without causing interference between the detection devices. Each of the detection devices has a light emitting source for projecting light intensity-modulated with a modulation period into the target space, a photodetector for receiving light from the target space, and an evaluation portion for detecting the spatial information of the target space from a change between the light projected from the light emitting source and the light received by the photodetector. The system includes a timing control portion for controlling the timings of projecting the lights from the light emitting sources such that a light projection period of the light emitting source of one of the detection devices does not overlap with the light projection period of the light emitting source of another detection device.

Abstract: A photoelectric conversion device is configured to include a light receiving region, for converting light to signal charges, and transistors. An insulation film is arranged on a surface of the light receiving region and under gate electrodes of the transistors. A first reflection prevention film of a refractive index higher than that of the insulation film is arranged at least above the light receiving region, to sandwich the insulation film between the first reflection prevention film and the light receiving region, and includes a silicon nitride film. An interlayer insulation film is arranged on the first reflection prevention film, and a second reflection prevention film is laminated between the first reflection prevention film and the interlayer insulation film. At least one of side walls of the gate electrodes of the transistors includes the silicon nitride film and a silicon oxide film arranged between the silicon nitride film and the gate electrodes.

Abstract: Methods and systems for multiforce high throughput screening are disclosed. According to one aspect, the subject matter includes a high throughput screening system that includes a multiforce plate having a plurality of field forming poles where each field forming pole is positioned on the multiforce plate at a location corresponding to a well in a multiwell plate. The system also includes an exciter assembly with excitation poles positioned at locations corresponding to the field forming poles. The excitation poles are utilized for electrically or magnetically coupling to the field forming poles and for delivering at least one of an electric and magnetic field in the vicinity of the field forming poles. The coupled field forming poles apply force via the field(s) to probes located in the wells of the multiforce plate in order to move the probes and test mechanical properties of specimens in the wells.

Abstract: Remote control systems that can distinguish predetermined light sources from stray light sources, e.g., environmental light sources and/or reflections are provided. The predetermined light sources can be disposed in asymmetric substantially linear or two-dimensional patterns. The predetermined light sources also can output waveforms modulated in accordance with one or more signature modulation characteristics. The predetermined light sources also can output light at different signature wavelengths.

Abstract: To reduce the probability of incorrect determination to detect an object reliably. A reflective photoelectric sensor is provided with: a light projecting device for emitting light; a light receiving device for receiving the optical feedback of the light that is emitted from the light projecting device; a determining portion for determining whether or not an object exists in the direction in which the light is emitted from the light projecting device, based on the optical feedback; and a reflection preventing plate of a moth-eye structure, disposed at a position that is on the optical path of the light that is emitted from the light projecting device at a position that is more distant than the location wherein the object is anticipated to appear.