Abstract: A system and method for characterizing the power and luminance values for a display. This may include testing a device to determine a luminance value for a display of a given device at a given current and determining whether the first current is to be adjusted during future uses based on a comparison of the luminance with at least one threshold value. This may also include storing an adjusted current value if it is determined that the first current is to be adjusted.

Abstract: An image display device includes an excitation light source; a fluorescent screen including a plurality of phosphor regions that are repeatedly formed in an in-plane direction and a retro-reflection region that reflects a part of incident light in the opposite direction of the incident light; a scanning unit that scans a surface of the fluorescent screen on which the phosphor regions and the retro-reflection region are formed with excitation light from the excitation light source; a photo detection unit that outputs signal value that varies on the basis of an incident light amount onto the photo detection unit; a reflection unit that reflects retro-reflection light of the excitation light directed from the retro-reflection region to the photo detection unit; and a control unit that causes the scanning unit to scan the fluorescent; detects boundaries between the phosphor regions and the retro-reflection region on the fluorescent screen based on the output signal of the photo detection unit, and controls a ligh

Abstract: An automated adaptive optics and laser projection system is described. The automated adaptive optics and laser projection system includes an adaptive optics system and a compact laser projection system with related laser guidance programming used to correct atmospheric distortion induced on light received by a telescope. Control of the automated adaptive optics and laser projection system is designed in a modular manner in order to facilitate replication of the system to be used with a variety of different telescopes. Related methods are also described.

Abstract: A method for controlling a photovoltaic (PV) panel in a PV system including a computing device that provides motor control signals and implements an iterative adaptive control (IAC) algorithm for adjusting an angle of the PV panel. The IAC algorithm relates P at a current time k (P(k)), an elevation angle of the PV panel at k (?S (k)), P after a next step (P(k+1)) and an elevation angle of the PV panel at k+1 (?S (k+1)). The algorithm generates a perturbed power value P(k+1) to provide a power perturbation to P(k), and calculates ?S (k+1) using P(k+1). The motor control signals cause the motor to position the PV panel to achieve ?S (k+1). A change in P resulting from the positioning is compared to a predetermined change limit, and only if the change in P is ? the change limit, again sensing P, and repeating the generating, calculating and positioning.

Abstract: A radiation sensor includes first and second pixels with a radiation absorption filter positioned over the first pixel and an interference filter positioned over both the first and second pixels. The combined spectral response of the absorption filter and the first pixel has a first pixel pass-band and a first pixel stop-band. The interference filter has a first interference filter pass-band substantially within the first pixel pass-band and a second interference filter pass-band substantially within the first pixel stop-band.

Abstract: An optical device comprising a quantum dot provided in a resonant confinement structure, an output from said confinement structure and a pulsed excitation source for said quantum dot, wherein the quantum dot is configured to allow the emission of photons having a first energy in response to a pulse from said excitation source, said resonant confinement structure providing optical confinement, the first energy being different to the resonant energy of the resonant confinement structure, the optical device further comprising a timing unit, said timing unit being configured to select photons which have been emitted from the quantum dot due to excitation by a pulse, the timing unit selecting photons emitted after the duration of the pulse which caused the emission of the photons.

Abstract: A jitter sensing mechanism for a gimbaled optical sensor system. In one example, the jitter sensing mechanism includes a faceted retro-mirror configured to allow a double-pass line-of-sight monitoring beam to sense line-of-sight jitter in a multi-axis gimbaled optical sensor system where the inner-most gimbal axis includes a 2:1 gain mirror.

Abstract: An optical scanning apparatus includes a reflecting mechanism, a light receiving element and a restricting mechanism. The reflecting mechanism reflects a light beam such that the irradiation point of the light beam moves in a predetermined scanning direction. The light receiving element is arranged in a movement plane defined by the light beam reflected by the reflecting mechanism, and the light receiving element outputs a light reception signal for adjusting the irradiation timing of the light beam in accordance with reception of the light beam reflected by the reflecting mechanism. The restricting mechanism positions the light receiving element relative to the movement plane.

Abstract: The light receiving device includes a pixel array, such as a two-dimensional pixel array, of pixels each having a light-receiving element for receiving input signal light, an output selecting unit for selecting the outputs of pixels within the pixel array, a selected output adding unit for adding and outputting the selected outputs of the pixels, and an amplifying unit for amplifying the output of the selected output adding unit.

Abstract: An LED module (MJ) wherein among apertures (21A to 21C) and pins (11A to 11C) to engage each other, the apertures (21A to 21C) are formed in a mounting board (20) and the pins (11A to 11C) are formed on a lens (10). The apertures (21A to 21C) and the pins (11A to 11C) regulate the directivity direction of the lens (10) to a specific direction by engaging each other in one kind of manner.

Abstract: An optical scanning projection module includes a scanning light component including a plurality of sub light sources and at least one light-splitting element, a main light reflective element, a scanning element and a photosensitive element. Sub light beams of the sub light sources are converged to form a main light beam. One of the sub light beams travels to the light-delivering element to form a partial reflective light beam and a partial penetrating light beam. With a scanning manner, the partial reflective light beam or the partial penetrating light beam is reflected by the scanning element to be an inspection light, and the main light beam is reflected by the scanning element to be a projection light. The photosensitive element outputs a sensing signal according to the inspection light. Thus, the optical scanning projection module controls the operation of the scanning light component according to the sensing signal.

Abstract: Various embodiments of methods and devices are provided for an optocoupler comprising a layer of dielectric optically semi-reflective and transmissive material disposed between an LED and a first photodetector located above an upper surface of the layer, and a second photodetector located beneath the lower surface of the layer. The layer reflects a first portion of light generated by the LED towards the first photodetector to generate LED feedback control signals, and transmits a second portion of light generated by the LED through the layer for detection by the second photodetector to generate isolated output signals.

Abstract: A optical control sensor system includes a driver controlling an operation of a light source coupled to an end of an optical fiber, an orthogonal signal generator, generating a set of different orthogonal signals controlling the driver, a terminal sensor coupled to another end of the optical fiber selecting a predetermined set of input orthogonal signals for converting them into component combinations, constituting output signals, and directing the output signals back to the optical fiber, a device coupled to the light sources and to the first end of the optical fiber for extracting output signals that have passed through a return path in the optical fiber, a detector converting optical output signals into electrical signals, and a selector and a decoder connected to the orthogonal signal generator indicating a current state of the optical control sensor system based on an analysis of the selected combinations of components in the output signals.

Abstract: In a method for controlling laser lights in an electronic device, a laser light function of the electronic device is enabled by switching on a first switch. The method samples predetermined pixels from a background color of a current slide displayed on a display screen at each predetermined time interval, and obtains RGB values of the predetermined pixels. A first average of R values and a second average of G values of the predetermined pixels are calculated. If the first average is greater than a predetermined color threshold value, the second laser light is enabled to emit laser with a second color. If the first average is less than or equal to the predetermined color threshold value and the second average is greater than the predetermined color threshold value, the first laser light is enabled to emit the laser with a first color.

Abstract: The invention relates to a beam combining device comprising a plurality of separate input beam paths (9) and at least one output beam path (10) for combining a plurality of input beams to at least one output beam. Devices of this type are required in order, for example, to combine the beams from a plurality of lasers each having a different radiation spectrum to form a single beam. It is an object of the invention to provide a compact and cost-effective beam combining device. In order to achieve this object, the invention proposes that one or a plurality of Risley prism pairs (1) are assigned to each input beam path (9) of the beam combining device, the prism pairs deflecting the input beam in an adjustable direction.

Abstract: An optical apparatus comprising a first mirror (12), a second mirror (14), and at least one support (30) for holding the second mirror in substantially a predetermined position relative to said first mirror (12), wherein said at least one support (30) comprises at least one actuator (32) arranged to adjust the position of the second mirror (14), and said optical apparatus further comprises at least one light source (40a-40-c) rigidly fixed to the first mirror (12) in a predetermined orientation for providing a beam of light (42a-42c) directed at said second mirror (14), at least one corresponding alignment sensor (46a-46c) for detecting the beam of light (44a-44c) reflected from said second mirror (14), and arranged to provide an output signal indicative of the position of the incident reflected beam, and a controller (50) arranged to receive said output signal, and to thereby control said actuator (32) to adjust the position of the second mirror (14).

Abstract: The invention relates to a sensor device (100) in which the spatial distribution of an input light (L1) emission from a light emitting area (121, 122) of a light source (120) can selectively be changed. The input light is propagated through an optical system (110) to produce some output light (L2). Changes of the input light are taken into account when the detected output light (L2) is evaluated. Thus it is for example possible to detect and/or eliminate optical disturbances occurring in the optical path outside an object region (3). The light source (120) may particularly comprise a plurality of a light emitting segments (121, 122) that can selectively be switched on or off.

Abstract: The invention relates to a method of monitoring a vital parameter of a patient by measuring attenuation of light emitted onto tissue of the patient, comprising the following steps: modulating the light with a modulation frequency or/and a modulation code; emitting the modulated light onto the tissue of the patient; collecting light which is transmitted through the tissue or/and which is reflected from the tissue; demodulating the collected light; analyzing the demodulated collected light with regard to interference with ambient light; determining a modulation frequency or/and a modulation code for which interference with the ambient light is minimized or falls under a predefined threshold; and setting the modulation frequency or/and the modulation code for modulating the light according to the determined modulation frequency or/and a modulation code for which interference with the ambient light is minimized or falls under a predefined threshold.

Abstract: There is provided a lighting device, comprising at least one light emitter, at least one reflector and at least one sensor. The sensor is positioned within a region which receives direct light from the light emitter when the light emitter is emitting light. In some embodiments, the light emitter comprises one or more light emitting diode. In some embodiments, the sensor is positioned between the light emitter and a power supply. In some embodiments, the reflector comprises at least one opening, and light emitted by the light emitter passes through the opening to the sensor. In some embodiments, the sensor is sensitive to only some wavelengths of visible light. Some embodiments are back-reflecting lamps, and some are forward-reflecting lamps.

Abstract: A system for generating extreme ultraviolet light may include a chamber, a target supply device configured to supply a target material into the chamber, a laser apparatus configured to output a laser beam to irradiate the target material, a wavefront adjuster configured to adjust a wavefront of the laser beam, an imaging optical system configured to focus the laser beam reflected by the target material, an image detector configured to capture an image of the laser beam focused by the imaging optical system, and a controller configured to control the wavefront adjuster based on the captured image.

Abstract: An optoelectronic measuring system comprises at least two transmission light sources that emit time-sequentially clocked, phased light. A compensation light source is controlled independently of the transmission light sources. A receiver receives the light radiated by the transmission light sources, and the compensation light source converts them into an electrical received signal. At least two evaluation units evaluate the received signal and generate one control signal each. At least two transmission paths each comprise a transmission light source, an evaluation unit and a clock generator. The clock generator generates the clock for the transmission light sources and for the evaluation unit. The evaluation units each generate a control signal. A control unit generates a compensation control signal from the control signals, with which the compensation light source is controlled and supplied.

Abstract: An optical measurement device for measuring an optical appearance of a surface of a sample includes a measuring head which can be brought into contact with the surface of the sample. The measuring head includes an illumination device for illuminating the surface with an illumination beam, and a detection device or detecting a response beam. The response beam is the response of the sample to the illumination beam. The detection device includes a screen for intercepting the response beam, where the screen extends approximately a quarter hemisphere in order to realize measuring head with a small contact area with the surface.

Abstract: An external control stand for a self-propelled construction machine. The construction machine has a working component that can be operated from the external control stand. The invention includes a lighting device for illuminating a ground section on the external control stand, as seen in the direction of travel, in front of, behind and/or below the external control stand.

Abstract: A surface plasmon resonance fluorescence analysis device emits a light beam to a prism in which a metal film is formed on a prescribed surface while changing an angle of incidence relative to the metal film in a state in which the light beam is totally reflected, measures light generated on a surface of the metal film, determines an angle at which the light beam enters the metal film based on a change in intensity of the measured light, adjusts the emitting direction of the light beam so that the light beam enters the metal film at the determined angle of incidence, and measures fluorescence generated on the surface of the metal film in a state in which the light beam is emitted the adjusted direction.

Abstract: A beam power source transmits a signal indicating power availability, receives a request for power in response, and beams power in response to the request.

Abstract: A unit pixel for an image sensor includes an accumulation circuit configured to generate an accumulated dark current by accumulating a charge corresponding to a dark current during a time of flight (TOF), the accumulation circuit being optically shaded to generate the dark current, an output voltage generation circuit configured to generate and output an output voltage corresponding to the TOF based on a charge corresponding to the accumulated dark current, a control circuit configured to control an operation of the output voltage generation circuit based on a light signal that is input to the unit pixel after being reflected by an object, the light signal being emitted by a light source, and an initialization circuit configured to initialize the accumulation circuit at a predetermined cycle.

Abstract: Various embodiments related to monitoring for optical faults in an optical system are disclosed. For example, one disclosed embodiment provides, in an optical system comprising a light source, a light outlet, and an optical element disposed between the light source and the light outlet, a method of monitoring for optical system faults. The method includes detecting, via a light sensor directed toward an interface surface of the optical element closest to the light source, an intensity of light traveling from the interface surface of the optical element to the light sensor, and comparing an intensity of light detected to one or more threshold intensity values. The method further includes identifying an optical system fault condition based on comparing the intensity of light detected to one or more threshold values, and modifying operation of the optical system.

Abstract: An optical semiconductor device includes a waveguide that an input light to be inputted, a ring modulator optically coupled with the waveguide, a first ring resonator optically coupled with the waveguide and having an optical path length smaller than an optical path length of the ring modulator, a second ring resonator optically coupled with the first waveguide and having an optical path length larger than the optical path length of the ring modulator, a heater arranged adjacent to the ring modulator, the first ring resonator and the second ring resonator, a first photodetector monitoring a light power in the first ring resonator, a second photodetector monitoring a light power in the second ring resonator, and a controller controlling the heater so that a resonance wavelength of the ring modulator agrees with a wavelength of the input light, based on signals detected by the first and second photodetectors.

Abstract: A method of computing peak spectral irradiance, the method comprising characterizing at least one light source to determine an irradiance distribution pattern, generating multiple density cones in a three dimensional model based on the irradiance distribution pattern, positioning the multiple density cones in a desired layout, measuring density of irradiance at one or more locations, and optimizing the positioning of the at least one light source to obtain a desired irradiance distribution.

Abstract: An optical device may include a mirror for respectively reflecting and transmitting parts of a first laser beam as first reflected and first transmitted beams, and for respectively transmitting and reflecting parts of a second laser beam as second transmitted and second reflected beams; an optical system disposed so that the first and second laser beams are such that beam paths of the first transmitted and second reflected beams are parallel or substantially coincide, or such that beam paths of the first reflected and second transmitted beams are parallel or substantially coincide; first and second measuring units configured to respectively measure a beam parameter of the first transmitted or first reflected beams, and of the second reflected or second transmitted beams; and first and second adjusting units configured to adjust the first and second laser beams based on measurement results by the measuring units.

Abstract: A light-emitting apparatus and a camera system including the same are disclosed. According to an aspect of the invention, a camera system is provided that includes a light source color detector for detecting a color temperature of a light source; an auxiliary light apparatus for changing a color temperature of auxiliary light according to the detected color temperature of the light source; and a white balance controller for adjusting white balance while the auxiliary light is being radiated. Accordingly, a photograph having a natural color sense can be reproduced by reducing a sense of color incongruity in a captured image.

Abstract: A system for controlling a light beam in an optical setup includes a light source that directs a collimated light beam along a path, through a sample, and toward the active area of a stationary detector. A lens is selectively movable into the path of the light beam for spreading the beam in instances where the path of the beam is altered by the sample between the source and the stationary detector. The detector, therefore, is held stationary. Adjustment mechanisms are provided for increasing the intensity characteristic of the light that reaches the detector to account for a decrease in intensity that occurs when the lens is in the path of the light beam to spread the beam.

Abstract: A system controller for position controlling a photovoltaic (PV) panel in a PV system including a power sensor sensing output power (P), and a motor for positioning the PV panel. The system controller includes a computing device having memory that provides motor control signals and implements an iterative adaptive control (IAC) algorithm stored in the memory for adjusting an angle of the PV panel. The IAC algorithm includes an iterative relation that relates P at current time k (P(k)), its elevation angle at k (?s (k)), P after a next step (P(k+1)) and its elevation angle at k+1 (?s (k+1)). The IAC algorithm generates a perturbed power value P(k+1) to provide a power perturbation to P(k), and calculates a position angle ?S (k+1) of the PV panel using the perturbed power value. The motor control signals from the computing device cause the motor to position the PV panel to achieve ?S (k+1).

Abstract: A light sensor system includes at least one light emitter, a light sensor unit and a processing unit. The light sensor unit is arranged to receive reflected light from an object in accordance with a time sequence in which the at least one light emitter is activated, and accordingly output a plurality of reflected signals. The processing unit is arranged to receive the reflected signals, identify a signal function of time by referring to occurrence sequence of local peak levels of the reflected signals, and determine motion of the object according to the signal function of time. Another light sensor system is proposed. The major difference between the two light sensor systems is that the processing unit of the another light sensor system is arranged to identify the signal function of time by comparing a predetermined threshold with signal levels of the reflected signals.

Abstract: The welding filter device includes a light sensor, a microprocessor, a liquid crystal display, and a user interface. The light sensor senses light to generate a welding signal and a light source intensity signal. The microprocessor comprises a determining module, a control module, a regulating module, and a storage module. The determining module receives the welding signal and determines whether to activate a welding mechanism. The control module receives the light source intensity signal and outputs a control signal. The liquid crystal display presents a first display status according to the control signal. The user interface is used to generate a setting signal; wherein when the liquid crystal display presents the first display status, the regulating module receives the setting signal to regulate the settings so that the liquid crystal display presents a second display status. Furthermore, a method for controlling the welding filter device is also disclosed herein.

Abstract: Various embodiments related to monitoring for optical faults in an optical system are disclosed. For example, one disclosed embodiment provides, in an optical system comprising a light source, a light outlet, and an optical element disposed between the light source and the light outlet, a method of monitoring for optical system faults. The method includes detecting, via a light sensor directed toward an interface surface of the optical element closest to the light source, an intensity of light traveling from the interface surface of the optical element to the light sensor, and comparing an intensity of light detected to one or more threshold intensity values. The method further includes identifying an optical system fault condition based on comparing the intensity of light detected to one or more threshold values, and modifying operation of the optical system.

Abstract: Disclosed herein are multispectral detection methods and systems that can be used with image-forming optics configured to form an image of a sample. The systems include: (a) an imaging detector; (b) relay optics that include multiple optical elements, the relay optics positioned to relay the image formed by the image-forming optics to the imaging detector; (c) an actuator coupled to one of the optical elements in the relay optics and configured to adjust a position of the coupled optical element; and (d) control electronics configured to cause the actuator to adjust the position of the coupled optical element in the relay optics in response to a wavelength band selection by a wavelength selection element positioned to select one wavelength band for the image from among two or more wavelength bands within an overall wavelength range.

Abstract: A laser crystallization apparatus and method are disclosed for selectively melting a film such as amorphous silicon that is deposited on a substrate. The apparatus may comprise an optical system for producing stretched laser pulses for use in melting the film. In still another aspect of an embodiment of the present invention, a system and method are provided for stretching a laser pulse. In another aspect, a system is provided for maintaining a divergence of a pulsed laser beam (stretched or non-stretched) at a location along a beam path within a predetermined range. In another aspect, a system may be provided for maintaining the energy density at a film within a predetermined range during an interaction of the film with a shaped line beam.

Abstract: The invention relates to a system for regulating an adjustable brightness level in a cabin of an aeroplane, having a control device, which is designed to regulate a preset brightness value and has at least the following components: an input unit for inputting a predetermined brightness value, at least one sensor detecting the brightness, an adjusting device for influencing at least one light source on the basis of a brightness value determined by the sensor.

Abstract: While one beam is being branched into a plurality of beams with different optical path lengths, the beams can be converged on the same position in the optical-axis direction with a simple structure even when relative angles between the beams differ. Provided is a beam splitter apparatus including a beam splitter that branches an input pulsed beam into two optical paths with different optical path lengths; relay optical systems that are disposed in the respective branching optical paths and that relay pupils in the optical paths; a beam splitter that multiplexes the relayed pulsed beams in the two optical paths; and a reflection optical system that endows pulsed beams branching off via the beam splitter with a relative angle.

Abstract: A quantum interference device includes: gaseous alkali metal atoms; and a light source for causing a resonant light pair having different frequencies that keep a frequency difference equivalent to an energy difference between two ground states of the alkali metal atoms, the quantum interference device causing the alkali metal atoms and the resonant light pair to interact each other to cause an electromagnetically induced transparency phenomenon (EIT), wherein there are a plurality of the resonant light pairs, and center frequencies of the respective resonant light pairs are different from one another.

Abstract: A photon detector is disclosed that includes, in addition to an immobilisable photon-sensitive element, a photon transmission element. The photon detector is configured such that it can vary photon intensities impacting upon the photon-sensitive element and transmitted by the photon transmission element, for example, by modifying an absorption property or a defocussing property of the photon transmission element. Also, the immobile photon-sensitive element, which can be, for example a SPAD (Single Photon Avalanche Diode), always operates close to the optimal operating range and below an immobilisation range. A distancing device that includes this type of photo detector is also disclosed.

Abstract: A light scanning device includes: a movable section which has a light reflection section reflecting light and oscillates around an oscillating axis and in which a maximum deflection angle thereof is variable; and a detection section which detects the maximum deflection angle of the movable section, wherein the detection section includes a light source which irradiates light toward the light reflection section, a light-receiving section which receives reflected light of the light from the light source, reflected by the light reflection section, and a displacement drive section which changes a position of the light-receiving section in accordance with the maximum deflection angle of the movable section.

Abstract: In an optical filter, a pair of polarization filters allows transmission of light therethrough when i) the light has a wavelength band equal to or more than a first wavelength regardless of a light oscillation direction, the wavelength band including a wavelength of infrared light and ii) the light has a wavelength band less than the first wavelength and is linearly polarized. An optical rotation control element, disposed between the paired polarization filters, allows the light to be transmitted therethrough during which optical rotation of the light is changed selectively depending on application or non-application of voltage to the optical rotation control element. The polarization filters have polarization planes, respectively, which are in parallel with each other or the polarization plane of one of the polarization filters is rotated from that of the other by an angular amount of rotation resulting from the polarization of the optical rotation control element.

Abstract: An apparatus measures positions of marks on a lithographic substrate. A measurement optical system comprises illumination subsystem for illuminating the mark with a spot of radiation and a detecting subsystem for detecting radiation diffracted by the mark. A tilting mirror moves the spot of radiation relative to the reference frame of the measurement optical system synchronously with a scanning motion of the mark itself, to allow more time for accurate position measurements to be acquired. The mirror tilt axis is arranged along the intersection of the mirror plane with a pupil plane of the objective lens to minimize artifacts of the scanning. The same geometrical arrangement can be used for scanning in other types of apparatus, for example a confocal microscope.

Abstract: An optical transceiver comprises a substrate having a temperature control device, a light source, a light-guiding fiber, a detector, optics for collimating the light from the light source, coupling optics for focusing the light beam into the light-guiding fiber, and a beamsplitter which sends one part of the collimated light beam into a wavelength stabilization unit and another part of the collimated light beam into the coupling optics. A wavelength stabilization unit detects and compensates for wavelength drift of the light source. The optical transceiver has a superluminescent diode for its light source and may, for example, be integrated in a fiber-optic gyro.

Abstract: A battery powered electronic appliance, including a first device, a visual display and a camera device having a camera sensor that is configured to sense ambient light in the environment of the electronic appliance; an ambient light measurement module coupled to the camera sensor that is configured to measure the sensed ambient light to produce an ambient light value that indicates a measured level of ambient light; and a light control module that is configured to determine a level of illumination of the visual display based on the ambient light value.

Abstract: An occupancy sensor is provided with a separable override unit to 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. The override unit having a light source is removably attached to the occupancy sensor. The override unit is coupled to the occupancy sensor to emit light to actuate the light sensor of the occupancy sensor, thereby preventing the occupancy sensor from being actuated regardless of the light level in the surrounding areas. A control unit is operatively connected to one or more override units for selectively controlling the normal operation of the occupancy sensor.

Abstract: A quantum interference device includes: gaseous alkali metal atoms; and a light source for causing a resonant light pair having different frequencies that keep a frequency difference equivalent to an energy difference between two ground states of the alkali metal atoms, the quantum interference device causing the alkali metal atoms and the resonant light pair to interact each other to cause an electromagnetically induced transparency phenomenon (EIT), wherein there are a plurality of the resonant light pairs, and center frequencies of the respective resonant light pairs are different from one another.

Abstract: An anti-glare protection device for a welding mask includes a transmission control circuit for determining a darkening signal from a control signal, a welding activity detection circuit (6) for detecting a welding activity, based on the output of a first sensor circuit. The welding activity detection circuit is arranged to control, via an activation switch, whether either the darkening signal or a signal corresponding to an undarkened optical filter is input to a filter drive circuit. The filter drive circuit drives a controllable optical filter to a transmission value according to the signal input to the filter drive circuit. A manual input device allows a user to manually adjust a user selected signal. A second sensor circuit determines a sensed signal. A manually operable mode selection switch for selecting either, in a manual mode, the user selected signal or, in an automatic mode, the sensed signal to be used as the control signal to the transmission control circuit.