Abstract: Method and apparatus for external cavity laser absorption spectroscopy There is disclosed an apparatus, and corresponding methods, for determining one or more characteristics of a sample in an absorption cell using laser absorption spectroscopy. For example, the characteristic may be concentration of a species in the sample. The apparatus comprises an external cavity semiconductor laser comprising a semiconductor gain medium within an optical resonator. The absorption cell is located within the optical resonator of the external cavity semiconductor laser so as to be optically coupled with the gain medium. A controller is arranged to provide a varied injection current to the semiconductor gain medium. A photodetector is arranged to detect laser light output by the external cavity semiconductor laser. An analyzer is arranged to determine one or more characteristics of the sample from behavior of the detected laser light output as a function of the varied injection current.

Abstract: A light-emitting diode (LED) emitter module includes a substrate having a plurality of base layers of an electrically insulating material, a plurality of electrical contacts disposed on a top one of the base layer, and a plurality of electrical paths coupled to the electrical contacts, wherein at least a portion of the plurality of electrical paths is disposed between the base layers. The emitter module also includes two or more groups of light-emitting diodes (LEDs), each group having one or more LEDs, and each of the LEDs is coupled to an electrical contact. The electrical paths are configured for feeding separate electrical currents to the groups of LEDs. The emitter module also includes a memory device containing information associating a plurality of output light colors with a corresponding plurality of combinations of electrical currents, each combination specifying an electric current for each of the two or more groups of LEDs.

Abstract: An electrical load controller includes an electrical switching device and an actuator assembly having at least one user actuator for use in turning power on and off to the load and for use in adjustably controlling the level of power to the load. A frame attached to the actuator includes an integrally formed backlightable indicator region having an outer continuous solid surface. Light from an illumination assembly related to the level of power to the load is directable onto a portion of an inner surface of the backlightable indicator region, transmittable through the backlightable region from the inner surface to the outer surface, emittable from a portion of the outer surface, and observable by the user.

Abstract: A light signal detecting circuit, a light amount detecting device, and a charged-particle-beam device capable of discriminating the signal component of a small amount of light from the signal component of noise due to dark current. A data-processing-unit detects pulses from digital voltage signal corresponding to an amount of light obtained by an amplifier and an A-D converter, calculates a crest value as the maximum voltage value of each pulse, and stores the occurrence frequency of each calculated crest value in a frequency occurrence storage area. A data analysis unit compares a previously-determined frequency lower limit with the occurrence frequency of each crest value in ascending order of the crest values and sets a pulse determination threshold to the first crest value whose occurrence frequency is equal to or smaller than the frequency lower limit. The threshold processing unit thus outputs the digital signal higher than the pulse determination threshold.

Abstract: A method and an apparatus for controlling an amount of light in a visible light communication system are provided. In the visible light communication system, a terminal measures an amount of light for a light signal received from a sensor, determines whether the measured amount of light is less than a threshold value, increases an amount of light for a light source signal to transmit to the sensor when the measured amount of light is less than the threshold value, and transmits, to the sensor, a light source signal according to the increased amount of light.

Abstract: A method of self-calibrating a lighting device, comprising: —monitoring a calibration area, which encompasses at least a part of an area being illuminable by the lighting device; and—calibrating the light output settings of the lighting device. The monitoring operation includes repeating: —detecting any relevant change, out of a set of relevant changes comprising at least a light intensity change, in the calibration area during a monitoring time, while keeping the light output of the lighting device constant; and—determining an amount of change within the monitoring time; until the amount of change is below a limit value. Thereby the lighting device does not perform the calibration until it has detected a period of no or small changes.

Abstract: A method and system for performing model-based registration and critical dimension measurement is disclosed. The method includes: utilizing an imaging device to obtain at least one optical image of a measurement site specified for a photomask; retrieving a design of photomask and utilizing a computer model of the imaging device to generate at least one simulated image of the measurement site; adjusting at least one parameter of the computer model to minimize dissimilarities between the simulated images and the optical images, wherein the parameters includes at least a pattern registration parameter or a critical dimension parameter; and reporting the pattern registration parameter or the critical dimension parameter of the computer model when dissimilarities between the simulated images and the optical images are minimized.

Abstract: An illumination optical unit for microlithography illuminates an object field with illumination light. The unit includes a first facet mirror that has a plurality of first facets, and a second facet mirror that has a plurality of second facets. The unit has facet pairs which include respectively a facet of the first facet mirror and a facet of the second facet mirror which predefine a plurality of illumination channels for illuminating the object field. At least some of the illumination channels have in each case an assigned polarization element for predefining an individual polarization state of the illumination light guided in the respective illumination channel.

Abstract: Embodiments of an ultrasound system for detecting a posture of a user and providing an optimal ultrasound image for the posture of the user are disclosed. The ultrasound system includes a display unit including a sensing unit installed in one side of a monitor. The sensing unit detects a position of a user, a distance between the user and the monitor, a height of the user with respect to the monitor and a viewing angle of the user toward the monitor to thereby form and output sensing signals corresponding thereto. The ultrasound system further includes a processing unit coupled to the sensing unit. The processing unit forms the ultrasound image by using ultrasound data and performs optimal image processing for the posture of the user upon the ultrasound image based on the sensing signals.

Abstract: The present disclosure provides a driving circuit, which includes a switch, a driver unit, a fault detection circuit, and a processor. The switch is coupled between a power terminal and an anode of a light emitting diode (LED) of a light source. The driver unit is coupled between a cathode of the LED and a ground for generating a driving current according to a control signal. The fault detection circuit operatively detects whether the cathode of the LED is shorted and generate a fault signal when detected that the cathode of the LED is shorted. The processor initiates a fault detection period, during which the processor turns off the switch and the driver unit causes the cathode of the LED to be floating while activates the fault detection circuit to detect whether the cathode of the LED is shorted.

Abstract: Controlling a photographing apparatus that can play back an image on an external display device, to achieve energy savings when playing back the image on the external display device is provided. After a photographed image is transmitted to the external display device, if a control signal is sourced by a remote control power to a back-surface LCD 102a and/or the touch panel 102b is turned off.

Abstract: A system and method of quantifying color and intensity of light sources including LEDs, HBLEDs (High Brightness LEDs), and other Solid State Lights (SSLs) using C-parameters to model a Spectral Power Distribution (SPD) to improve precision, accuracy, repeatability and usefulness of measurement of optical properties of wavelength and radiant flux in manufacturing of an object, designing products and processes that use the object, and describing/defining the object, is provided.

Abstract: Disclosed embodiments relate to techniques for operating a backlight unit of a display device in a redundant mode and a non-redundant mode in the event of an open circuit condition or short string condition. For instance, in a redundant mode, multiple LED strings are driven to provide a first quantity of light, such that the combined output from all LED strings is capable of providing a total light output corresponding to a maximum brightness setting for the display device. In the case that one of the LED strings fails due to an open circuit condition or short string condition, the remaining LED strings may be driven to provide a second quantity of light that is greater than the first, such that the combined light output from the remaining LED strings provides the same total light output for achieving the maximum brightness setting.

Abstract: A display device that displays an image, includes: a light source; an aperture stop array including a plurality of aperture stops; a lens array including a plurality of lenses which are disposed corresponding to the plurality of aperture stops respectively, and focus the light transmitted through the plurality of aperture stops respectively; a deflecting unit deflecting a travelling direction of the focused light respectively; a spatial light modulator that is illuminated by the deflected light, and modulates the illumination light; a detector that detects an observer; and a controller that calculates a position of a pupil of the observer based on a detection result by the detector, calculates a relative position of the display device and the pupil of the observer based on the calculation result, and controls an aperture amount of the plurality of aperture stops and a deflecting amount of the deflecting unit based on this calculation result.

Abstract: A tunable etalon, driver circuit, a light receiving device, an I-V convertor circuit connected to the light receiving device, an amplifier circuit having a gain switching function, an AD convertor, a microprocessor, and a voltage setting memory having a gain table as data of gain of the amplifier circuit are provided, and preliminary measurement of a light reception voltage is performed based on a current detected by the light receiving device, and the gain of the amplifier circuit is adjusted to adjust the light reception voltage obtained by the preliminary measurement to a dynamic range of the AD convertor with reference to the gain table of the gain of the amplifier circuit with respect to the light reception voltage obtained by the preliminary measurement stored in the voltage setting memory.

Abstract: A device manufacturing method includes conditioning a beam of radiation using an illumination system. The conditioning includes controlling an array of individually controllable elements and associated optical components of the illumination system to convert the radiation beam into a desired illumination mode, the controlling including allocating different individually controllable elements to different parts of the illumination mode in accordance with an allocation scheme, the allocation scheme selected to provide a desired modification of one or more properties of the illumination mode, the radiation beam or both. The method also includes patterning the radiation beam having the desired illumination mode with a pattern in its cross-section to form a patterned beam of radiation, and projecting the patterned radiation beam onto a target portion of a substrate.

Abstract: Systems and methods use cameras to provide autonomous navigation features. In one implementation, a traffic light detection system is disclosed. The system may include at least one image capture device configured to acquire a plurality of images of an area forward of the vehicle, the area including a traffic lamp fixture having at least one traffic light. At least one processing device may be configured to align areas of the plurality of images corresponding to the traffic light, based on a determined center of brightness, expand each pixel within the aligned areas, determine a set of average pixel values including an average pixel value for each set of corresponding expanded pixels within the aligned areas, and determine, based on the set of average pixel values, whether the traffic light includes an arrow.

Abstract: This disclosure provides systems, methods and apparatus of establishing a free-space communication link through a medium. The medium can be an occluded environment with increased absorption and/or scattering effects. The free-space communication link includes a transmitter configured to transmit an optical signal at a wavelength suitable for transmission through the medium without suffering excessive optical losses due to absorption and/or scattering effects. The free-space communication link includes a receiver configured to receive the transmitted optical signal. The transmitter-receiver pair is configured to efficiently transmit optical signals at the suitable wavelength over a distance between about 1 mm and about 50 m. The transmitter and the receiver can be configured as portions of a fiber-optic connector assembly that can be used to connect two fiber-optic cables in an occluded environment.

Abstract: A light receiving and emitting element includes a substrate; a light emitting element formed on an upper face of the substrate; a light receiving element formed on an upper face side of the substrate; a light emitting element-side first electrode pad; and a metal lump joined to the light emitting element-side first electrode pad. The light emitting element-side electrode pad is disposed the upper face of the substrate through an insulating layer so that the metal lump blocks light emitted from the light emitting element and propagating toward the light receiving element.

Abstract: The detector that detects a light beam emitted from a light source of a second image forming device and reflected by a polygon mirror, and an adjustment device that performs adjustment processing of adjusting the velocity of the polygon mirror based on an output of the detector are provided. Before a first image forming device performs the image forming processing, the adjustment device performs the adjustment processing while causing the light source of the second image forming device to emit the light beam during a time period including at least a time period in which a photosensitive member of the second image forming device is emitted with the light beam. Before the adjustment processing is finished, the first image forming device starts to move a developing member to a developing position.

Abstract: A system that measures deviation of printed color at selected locations on a moving substrate from a target color. The system comprises using a printed test image of target color, a calibrated spectrophotometer to provide spectral response values of the target color on the test image, a photonic device that provides tri-stimulus values from inline printed images and a computing device. The computing device compares the tri-stimulus values to spectral response values for the test image to calculate a spectral transformation matrix at each location selected to remove variations in optical and mechanical parameters. The spectral transformation matrix is applied to future mapped sets of tri-stimulus values of printed colors captured by the photonic device from selected locations to determine in real-time the deviation of color and thereby control color quality.

Abstract: Power supplies and methods for regulating performance of image intensifiers are disclosed. Performance is regulated by controlling the duty factor of the image intensifiers.

Abstract: Provided is an optical unit with a blur correction function, wherein even when a photoreflector and a drive mechanism for blur correction are provided in a movable module provided with an optical element, sizes in an optical axis direction and a direction crossing the optical axis direction can be prevented from increasing. In an optical unit (100) with a blur correction function, a drive mechanism (500) for blur correction is provided between the outer peripheral surface of an image capturing unit (1) and a fixed body (200) (upper cover (250)), and a first photoreflector (580) and a second photoreflector (590) are provided between a bottom portion (substrate (15)) of the image capturing unit (1) and the fixed body (200) (lower cover (700)), between which a swing support (180) is provided.

Abstract: Since it is difficult to emit a stable and reliable modulated lightwave signal by means of IQ modulators used for QAM format, a method for controlling an optical transmitter according to an exemplary aspect of the invention includes the steps of (a) keeping an optical amplitude of a continuous wave light output from the optical transmitter constant, (b) making operating point values in optical modulation converge to predetermined values during step (a), and (c) modulating the continuous wave light with multiple amplitudes and phase levels around the operating point values converged in step (b).

Abstract: A lighting system having at least three light sources receives an input relating to color coordinates of a target point representing a desired color characteristic for a combined output from the light sources. The system provides color tunable output and/or dimmable output in response to differences in user input. The system also corrects changes in performance of the light sources due to lifetime degradation in each of the light sources. After a period of system operation, outputs of the sources are measured. The system increases the luminosity outputs of each of the light sources by a respective amount relative to the degradations measured in all the light sources; in this manner, the luminosity outputs of the light sources remain substantially constant in relations to each other over the lifetime of the light sources.

Abstract: An optical signal demodulator includes: an obtaining unit configured to obtain a spectrum of an optical signal generated by a second signal being superimposed on a first signal using frequency modulation; an identifying unit configured to identify a peak wavelength which is a wavelength corresponding to a peak position of the spectrum; and a demodulating unit configured to demodulate the second signal from the optical signal using a wavelength-variable filter to which a transmitted wavelength band has been set based on the peak wavelength.

Abstract: A method of sensing magnitude of lumen depreciation not only of a lamp of a lighting fixture, but other factors, by sensing a relative light level external of the lighting fixture to derive not only lamp lumen depreciation but total lumen depreciation from the fixture. An apparatus of monitoring light level of one or more lighting fixtures comprises a sensor positioned external of the lighting fixture(s), a comparator adapted to compare a measured actual lumen output signal from the sensor to a pre-set reference or threshold lumen output value. An error signal is generated by the comparator if the comparison indicates actual lumen output to have dropped below the reference or threshold lumen output. An alarm or communication can be actuated by the error signal to instruct corrective action to ensure relatively constant light levels to be maintained for the lighting system over time, thus providing ongoing assurance to the end user of proper system operation.

Abstract: Timing is determined in positron emission tomography (PET). Two or more different types of timing detection are used for each event. The difference in time from the different types of timing detection may indicate whether or not an error has occurred. An average difference or other typical offset difference may be used to correct the error. During pile up, the difference information may be used to create a missing time, such as using an average difference between second derivative and constant fraction discrimination as an offset to determine constant fraction timing from second derivative timing.

Abstract: In accordance with certain embodiments, lighting systems include one or more lightsheets each including a plurality of strings of light-emitting elements, control elements, and power conductors for supplying power to the light-emitting elements and control elements.

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: Disclosed embodiments relate to techniques for operating a backlight unit of a display device in a redundant mode and a non-redundant mode in the event of a shorted LED failure condition. For instance, in a redundant mode, multiple LED strings arranged in an end-to-end configuration are each driven to provide a first quantity of light, such that the combined output from all LED strings is capable of providing a total light output corresponding to a maximum brightness setting for the display device. In the case that an LED on one of the strings fails due to a shorted LED failure condition, the remaining functional LEDs of the affected string may be driven to provide a second quantity of light, such that the combined output from the affected strings and the non-affected strings may still provide the same total light output for achieving the maximum brightness setting. The second quantity of light is greater than the first quantity.

Abstract: The optical scanning device includes a photoreceptor, a light source unit, a plurality of correction value storage units and a light quantity correction unit. The scanning position in the photoreceptor is divided into a plurality of areas. The target correction amount of the light quantity is predetermined so as to change according to the scanning position. The correction value storage unit stores the light quantity correction value that is associated with each of the areas. The light quantity correction unit corrects the light quantity during scanning by using the light quantity correction value corresponding to the scanning position. The length of each of the areas is shorter in an area in which the variation in the target correction amount per unit length is greater. The light quantity correction value is determined based on the target correction amount according to the area corresponding to the light quantity correction value.

Abstract: In a method of a computing device for calibrating light channels, one or more channel options of an illumination selecting unit of the computing device are selected to turn on the one or more light channels of a light source device. A camera unit captures a first image of the light source device. A zone and a serial number of each light channel are marked on the first image. Each channel option of the illumination selecting unit is eliminated. The camera unit captures a second image of the light source device when a light channel is turned off. The first image and the second image are compared, and a correlation between the light channel that is turned off and the eliminated channel option is determined. The serial numbers of the channel options are modified and remapped according to correlations between each light channel and each channel option.

Abstract: An apparatus used with a laser apparatus may include a chamber, a target supply for supplying a target material to a region inside the chamber, a laser beam focusing optical system for focusing a laser beam from the laser apparatus in the region, and an optical system for controlling a beam intensity distribution of the laser beam.

Abstract: An apparatus used with a laser apparatus may include a chamber, a target supply for supplying a target material to a region inside the chamber, a laser beam focusing optical system for focusing a laser beam from the laser apparatus in the region, and an optical system for controlling a beam intensity distribution of the laser beam.

Abstract: A method, apparatus, and system for compensating for lamp lumen depreciation. The method includes operating the lamp under rated wattage for a period towards the first part of operating life of the lamp. Operating wattage is increased at one or more later times. Energy savings are realized. The increases also restore at least some light lost by lamp lumen depreciation. The apparatus uses a timer to track operating time of the lamp. A few wattage changes made at spaced apart times can be made in a number of ways, including changing capacitance to the lamp, or using different taps on the lamp ballast. In one aspect the invention pertains to solid state sources. The invention can pertain to a variety of applications including wide area lighting, indoor lighting, pathway lighting, parking lot lighting, street lighting, under-counter or -cabinet lighting, and others.

Abstract: A method, system and apparatus for dynamically monitoring and calibrating display tiles are provided. The apparatus comprises: an array of light emitting devices; one or more light emitting devices paired with light emitting devices of the array; one or more sensors configured to detect an optical characteristic and/or an electrical characteristic of the one or more paired light emitting devices; and, circuitry configured to: drive the array; drive each of the one or more further light emitting devices under same conditions as light emitting devices of the array; temporarily drive each of the one or more paired light emitting devices under different conditions from the array; and, adjust driving of the array based on the optical characteristic and/or electrical characteristic of the one or more paired light emitting devices detected at sensor(s) when the one or more paired light emitting devices are driven under the different conditions.

Abstract: A system including a transmitter and a receiver that are loosely synchronized, the transmitter encodes signal waveforms having a start time, a width and a height that are determined based on a range of possible relative drifts of a receiver clock with respect to a transmitter clock and the receiver decodes the waveforms based on a sequence of tests, chosen to account for any uncertainty that may arise due to the lack of tight synchronization.

Abstract: A light source includes a semiconductor light emitter having an electrical drive input and operatively configured to emit a light beam; a first weakly polarizing beam splitter positioned to capture the light beam, reflecting one portion, and transmitting another portion with an output intensity P. The light source includes a second polarizing beam splitter positioned to capture the reflected portion of the light beam and split it into first and second detector light beams of orthogonal polarizations. The light source further includes first and second detectors capturing those detector light beams, and is configured to deliver corresponding first and second output signals from corresponding detector outputs. The light source includes an electronic circuit coupled to those electrical outputs and to the electrical drive input of the light emitter.

Abstract: An apparatus and method of operation for a high power broad band elongated thin beam laser annealing light source, which may comprise a gas discharge seed laser oscillator having a resonance cavity, providing a seed laser output pulse; a gas discharge amplifier laser amplifying the seed laser output pulse to provide an amplified seed laser pulse output; a divergence correcting multi-optical element optical assembly intermediate the seed laser and the amplifier laser. The divergence correcting optical assembly may adjust the size and/or shape of the seed laser output pulse within a discharge region of the amplifier laser in order to adjust an output parameter of the amplified seed laser pulse output. The divergence correcting optical assembly may comprise a telescope with an adjustable focus. The adjustable telescope may comprise an active feedback-controlled actuator based upon a sensed parameter of the amplified seed laser output from the amplifier laser.

Abstract: An intensity of radiation emitted from at least two laser diodes of a projecting apparatus is optimized by providing an offset distance between at least two focal points of the at least two laser diodes and providing a maximum value for radiation intensity emitted by each of the laser diodes, irrespective of simultaneous transmission by one of the laser diodes with another of the laser diodes. The intensity of the radiation emitted from each of the at least two laser diodes is adjusted such that an aggregated value of the radiation intensity emitted by all of the laser diodes within a predefined period of time may exceed a threshold value allowed for the maximum permissible exposure to radiation.

Abstract: A solid state light source module includes two solid state light sources, a light combining device for combining the lights from the two sources, a color wheel receiving the combined light and alternatingly outputting at least two primary color lights, a sync signal generator coupled to the color wheel for generating a periodic sync signal, and a controller for supplying a drive signal to each solid state light sources based on the sync signal. During at least one sub-period of the period, one of the two solid state light sources is turned on by its drive signal and the other one is kept in an inactive state by its drive signal.

Abstract: Provided are assemblies and processes for activating light emitting devices. A first current sink is in electrical communication with a common source through a current node and configured to draw a first current through the current node in response to a respective control signal. A second current sink is also provided in electrical communication with the current node and in parallel with the first current sink, also configured to draw a second current through the current node in response to a respective control signal. An aggregate current is drawn through the array, determined as a combination of the first and second currents. A commanded current from the first current sink can be shunted around the second array and the second current sink, providing a capability to series both the first and second laser diode light-emitting arrays, while simultaneously drawing different current amplitudes through each array from a common potential source.

Abstract: An electron beam emitter comprises a housing enclosing a cathode capable of emitting electrons within the housing and a window for allowing the emitted electrons to exit the housing, wherein the housing has an opening adapted to be at least partly engaged with a high voltage connector assembly, the assembly being adapted to connect the cathode to a power supply, the electron beam emitter further comprising a cooling flange surrounding the opening and having an interior channel extending between an inlet port and an outlet port for receiving cooling fluid for cooling the high voltage connector assembly. The invention further relates to a method of cooling an electron beam device.

Abstract: An optical encoder includes a light source, a scale which is irradiated by the light source and has a fine pitch pattern and a coarse pitch pattern in one track, a photo detector array which detects transmitting light or reflected light from the scale which are emitted from the light source, a signal processing unit including a first initial-stage amplifier unit that generates a position detection signal from the photo detector array, and a control unit that uses an output signal from the first initial-stage amplifier unit to control a light amount variation of the light source. The optical encoder can operate in a high resolution detection mode that forms the photo detector array at a first pitch to detect the fine pitch pattern and a low resolution detection mode that forms the photo detector array at a second pitch to detect the coarse pitch pattern.

Abstract: Embodiments of the invention provides methods and systems for synthesizing optical signals with high frequency stability. Using a set of external optical signal manipulators and control systems, embodiments of the invention enhance the resolution of any frequency reference and thereby alleviates the needs for ultra-high-Q cavities in frequency-stable optical signal synthesis. The invention consequently improves the performance of any optical signal generator by a substantial margin, while maintaining the system complexity and power dissipation at levels comparable to the original systems.

Abstract: A bidirectional beam director includes a pair of optically coupled diffraction gratings, each being independently rotatable so that a laser beam passing through the pair of gratings can be steered by rotation of at least one of the gratings. The bidirectional beam can be coupled to many types of optical systems, including optical phased arrays, multi-beam laser transmitters and receivers, telescopes, and high energy laser beam control systems.

Abstract: A photoelectric sensing sensitivity adjusting device includes: an LED for emitting light by being supplied with energy (current or voltage); a regulator for LED driving for supplying the energy to the LED; a light receiving device for receiving the light emitted from the LED; a digital potentiometer for controlling increase or decrease of the energy to be supplied to the LED; a CPU for digitally controlling, according to a control program, the increase or decrease of the energy to be supplied to the LED; and a photodetection portion for detecting an optical signal, converting the optical signal to an electrical signal, and outputting the electrical signal.

Abstract: Even when some light emitting elements among the plurality of light emitting elements fail, a repeater, can be continuously operated. Means for solving the problems A light source unit 50 which includes a plurality of pumping light source modules 51 (51a to 51d) which include light emitting elements 52 (52a to 52d) for emitting an excitation light and monitor elements 53 (53a to 53d) for monitoring the excitation lights of the light emitting elements 52 (52a to 52d), respectively, a distribution unit 40 which combines the excitation lights from the plurality of pumping light source modules 51 (51a to 51d) and distributes it, and a control unit 60 which supplies a drive current flowing serially through the plurality of light emitting elements 52 (52a to 52d) in a plurality of excitation modules 51 (51a to 51d) are included.

Abstract: A lighting panel includes a tile having a first side parallel to a principal plane of the lighting panel, a plurality of solid state lighting devices arranged on the first side of the tile and configured to emit light, a reflector sheet on the first side of the tile, and a brightness enhancement film on the reflector sheet. The reflector sheet may be arranged between the tile and the brightness enhancement film and the brightness enhancement film may be configured to increase the on-axis intensity of emitted light. A luminaire adapted for general illumination includes a lighting panel as described above, a current supply circuit configured to supply an on-state drive current to a string of lighting devices in response to a control signal, a photosensor arranged to receive light from one of the solid state lighting devices, and a control system configured to receive an output signal from the photosensor and to adjust the control signal responsive to the output signal of the photosensor.