Abstract: An illumination system is disclosed that is arranged to compensate for variations in brightness between different LEDs in the system. The system may include an array of LEDs coupled to a light guide that is provided with a plurality of light extraction patterns. Each light extraction pattern may include a plurality of light extraction features. The light extraction patterns may differ from one another in the density of the features. Light extraction patterns having a greater density may be combined with LEDs in the array that are less bright, whereas light extraction patterns having a lower feature density may be combined with LEDs in the array that are brighter.

Abstract: A light-emitting device comprising: a light source; and a light guide that is optically coupled to the light source, the light guide including a plurality of first non-fluorescent light extraction elements and a plurality of second non-fluorescent light extraction elements that are printed on the light guide, each of the first light extraction elements having a reflectance that is higher than a reflectance of any of the second light extraction elements, each of the first light extraction elements having a light transmittance that is lower than a light transmittance of any the second light extraction elements, each of the first light extraction elements having the same shape and size as any other one of the plurality first light extraction elements, and each of the second light extraction elements having the same shape and size as any other one of the plurality of second light extraction elements.

Abstract: An apparatus is disclosed including a light guide and a plurality of light emitting diodes (LEDs). The light guide includes a rear portion including a first edge, a second edge, and a rear edge. The first edge meets the rear edge at a first obtuse angle, and the second edge meets the rear edge at a second obtuse angle. The plurality of light emitting diodes (LEDs) disposed on the first edge, the second edge, and the rear edge, and it is arranged to produce an asymmetric light distribution pattern including a rear light emission and a forward light emission having a greater peak intensity than the rear light emission.

Abstract: Interlocking light emitting diode (“LED”) light guide tiles are disclosed. The tiles have interlocking edge features that provide physical interlock fitting between tiles and present a continuous appearance, both in an “on,” where LEDs are powered on and emitting light state and an “off” state, where LEDs are powered off and not emitting light. The LED light guide tiles interface with LEDs (housed in or embodied as integrated circuit LED packages) to output light through the surfaces of the light guide. The interlocking edge features of the light guide tiles are shaped to obscure or block an image of the LED packages from being seen by observers looking at the light guide tiles. Light guide tile assemblies or installations can be easily formed out of interchangeable tiles with little or no requirement for relative directional alignment of the tiles.

Abstract: A light emitting diode (“LED”) module is disclosed. The LED module includes a first LED tap and a second LED tap, the first tap being powered on for a longer amount of time than the second LED tap, based on an alternating current voltage. The LED module also includes a first LED package on which a first LED associated with the first LED tap and a second LED associated with the second LED tap are disposed. The LED module further includes a second LED package on which a third LED associated with the first LED tap and a fourth LED associated with the second LED tap are disposed.

Abstract: A control circuit for a light emitting diode (LED) lighting system for achieving a dim-to-warm effect is provided. The control circuit includes an LED controller, a clamp circuit coupled to a set of warm correlated-color-temperature (“CCT”) LEDs, a switch coupled to a set of cool LEDs, and a feedback circuit coupled to the clamp and the switch. The LED controller is configured to control the clamp circuit to clamp current through the set of warm LEDs based on the input current, and control the switch to switch on the set of cool LEDs responsive to the input current being greater than a first threshold level and to switch off the set of cool LEDs responsive to the input current being lower than the first threshold level. The feedback circuit is configured to divert current from the set of warm LEDs to the set of cool LEDs.

Abstract: In one embodiment, an overhead street light (a luminaire) is formed that has an asymmetric light intensity distribution, where the peak intensity is greatest along the direction of the street, lower directly across the street, and much lower on the house side of the street. Around the edge of a circular transparent light guide are white light LEDs that inject light into the light guide. To help control the asymmetry of the light intensity distribution, sawtooth-shaped grooves are formed in the light guide surface opposite to the light-emission surface and parallel to the street. Gaussian diffusers are used to partially diffuse the light. By proper selection of the grooves, the Gaussian diffuser, and the relative amounts of light emitted by LED segments around the light guide, the desired asymmetrical light intensity distribution is achieved while a direct view of the light exit surface appears as a uniform light.

Abstract: A method for improvement of contrast in an image shown on a display having a range of displayable video levels. The method comprises providing input video levels representing the image, said levels being within said displayable range; providing a transfer function (120, 121) having a slope greater than one everywhere in a gain region (130) of said displayable range, and a slope greater than zero and less than one everywhere in a softclip region (131) of said displayable range, said regions (130, 131) meeting at a threshold level (125), the transfer function (120, 121) being adapted to transfer any input video level within said displayable range to an output level within displayable said range; and transforming said input levels into output levels within said range, using the transfer function (120, 121). According to the invention, instead of “hardclipping” there is a “softclipping” of levels. Hence, compared to conventional methods, a higher gain may be used.

Abstract: The present invention proposes a method of providing illumination for a display device including a lighting unit having a plurality of light sources (104). Desired light outputs are determined (210) for each of the light sources (104) in accordance with image data to be displayed. The desired light outputs are compared (220) to a reference light output, and the difference is used to determine a power saving factor. The desired light output for one or more light sources is then increased (230) using the power saving factor. When the lighting unit is activated in accordance with these gained light outputs, a high contrast image is rendered on the display screen, which appears particularly visually appealing to a viewer. Optional steps (312)-(316) compensate for optical cross talk between adjacent backlight segments.

Abstract: A method for displaying images on a display having backlight is disclosed, where the images is updated periodically with a period. The method comprises the steps of: generating a signal with a pulse pattern for each period depending on the contents of an image to be displayed in that period; and activating backlight in accordance with the signal. Further, a display (100) comprising a display panel (102) and a backlight unit, wherein the backlight unit comprises a controller (104) and a lighting device is disclosed. The controller (104) is arranged to generate a control signal, and the lighting device is arranged to provide backlight to the display panel (102) according to the control signal, wherein the control signal comprises a pulse pattern depending on contents of displayed images.

Abstract: A method for improvement of contrast in an image shown on a display having a range of displayable video levels. The method comprises providing input video levels representing the image, said levels being within said displayable range; providing a transfer function (120, 121) having a slope greater than one everywhere in a gain region (130) of said displayable range, and a slope greater than zero and less than one everywhere in a softclip region (131) of said displayable range, said regions (130, 131) meeting at a threshold level (125), the transfer function (120, 121) being adapted to transfer any input video level within said displayable range to an output level within displayable said range; and transforming said input levels into output levels within said range, using the transfer function (120, 121). According to the invention, instead of “hardclipping” there is a “softclipping” of levels. Hence, compared to conventional methods, a higher gain may be used.