Abstract: An electronic device may have a display such as a liquid crystal display. The display may have an array of pixels that display images to a user. Backlight structures may provide the array of pixels with backlight illumination at a backlight illumination level. The backlight structures may have a light source with an array of light-emitting diodes and photoluminescent material that is pumped by pump light from the light-emitting diodes. The backlight illumination may experience color variations as a function of the backlight illumination level. Circuitry in the electronic device may be used to implement a backlight level color compensator. The backlight level color compensator may apply color correction factors to the image data of the displayed images to compensate for variations in color of the image data due to variations in backlight illumination level and operating temperature.

Abstract: A display may have an array of pixels that display images for a user. The backlight unit may have a light-guide layer. An array of light-emitting diodes may emit light into an edge of the light-guide layer. The light guide layer may overlap a backlight reflector. The backlight reflector may include a backlight reflector panel formed from a stack of dielectric layers on a rectangular substrate. The backlight reflector may also include a strip of backlight reflector tape having an edge that is overlapped by an edge portion of the backlight reflector panel. Color compensating features such as printed colored ink patterns may be formed on the backlight reflector to adjust the color of backlight illumination in portions of the backlight unit adjacent to the light-emitting diodes.

Abstract: A packaged LED device having a textured encapsulant that is conformal with a mount surface on which at least one LED chip is disposed. The textured encapsulant, which can be textured using an additive or subtractive process, is applied to the LED either prior to or during packaging. The encapsulant includes at least one textured surface from which light is emitted. The textured surface helps to reduce total internal reflection within the encapsulant, improving the extraction efficiency and the color temperature uniformity of the output profile. Several chips can be mounted beneath a single textured encapsulant. A mold having irregular surfaces can be used to form multiple encapsulants over many LEDs simultaneously.

Abstract: Provided are devices and methods for grouping light emitters and devices including the same. Embodiments of such methods may include selecting a portion of the light emitters using a region of a multiple axis color space that is configured to represent each of a plurality of colors as at least two chromaticity coordinates. The region may be proximate a predefined point on the multiple axis color space and includes a major axis having a first length and a minor axis having a second length that is less than the first length.

Abstract: A display device is provided. The display device includes a light source emitting a blue light and a light emitting layer including a first group of red quantum dots and a second group of green quantum dots. The light emitting layer is configured to absorb a first portion of the blue light from the light source to emit red light and green light and to transmit a second portion of the blue light. The display device also includes dichroic filter layers to improve light recycling and backlight efficiency.

Abstract: Display backlight structures may provide backlight illumination that passes through display layers in the display. Light-emitting diodes may emit blue light into an edge of a light guide plate. Optical films may overlap the light guide plate. The optical films may include a quantum dot enhancement film. A peripheral strip of yellow reflector or other light control structures may be incorporated into the backlight structures to reduce blue edge effects. The light control structures may have features with a spatially varying density, may be formed from quantum dot enhancement film, or may be formed form other structures. The light control structures may be formed on the surfaces of the optical films, on a reflective layer under the light guide plate, or on a surface of a mold frame or other structure that lies in a plane parallel to the plane of the light guide plate.

Abstract: A display has an array of display pixels formed from display layers such as one or more polarizer layers, a substrate on which an array of display pixel elements such as color filter elements and downconverter elements are formed, a liquid crystal layer, and a thin-film transistor layer that includes display pixel electrodes and display pixel thin-film transistors for driving control signals onto the display pixel electrodes to modulate light passing through the display pixels. A light source such as one or more laser diodes or light-emitting diodes may be used to generate light for the display. The light may be launched into the edge of a polymer layer or other light guide plate structure. A light guide plate may include phase-matched structures such as holographically recorded gratings or photonic lattices that direct the light upwards through the array of display pixels.

Abstract: Provided are devices and methods for providing front-of screen uniformity. Methods include estimating a filter function corresponding to the display and selecting multiple light emitters as a function of characteristics corresponding to light transmitted from the display as determined via the filter function. Devices are provided that include multiple light emitters including a first chromaticity difference corresponding to the multiple light emitters and a second chromaticity difference corresponding to the multiple light emitters and a filter function, wherein the second chromaticity difference is less than the first chromaticity difference.

Abstract: A liquid crystal display (LCD) device includes a pixel array including a plurality of pixels configured to display an image. The plurality of pixels respectively include a first subpixel configured to display first color image data, and a second subpixel configured to display second and third color image data. The LCD device may further include a backlight configured to emit the first, second, and/or third colors of light, and a backlight controller. The backlight controller may be configured to activate the backlight to emit the first and second colors of light at a same time to generate a first image component including a combination of the first color image data and the second color image data, and to separately emit the third color of light at a different time than the first and second colors of light to generate a second image component including the third color image data. The pixel array may be configured to display the first and second image components to provide a single image frame.

Abstract: An illumination module includes a longitudinal support member including a base portion and a pair of sidewalls extending from the base portion that together define a channel that extends in a longitudinal direction. A printed circuit board (PCB) on the base portion extends in the longitudinal direction within the channel. A plurality of light emitting diodes (LEDs) are on the PCB in a linear array. A reflective sheet is within and extends across the channel, and includes a plurality of holes that correspond with locations of the LEDs on the PCB, and the LEDs are positioned in the holes. An optical film extends across the channel above the reflective sheet and defines an optical cavity between the reflective sheet and the optical film. The optical film, the reflective sheet and the sidewalls of the support member recycle light in the optical cavity.

Abstract: Provided are solid state backlight devices and methods for forming the same. A solid state backlight unit according to some embodiments of the invention includes a housing having a major surface and multiple LEDs on a first surface of the major surface. The solid state backlight unit also includes a specular reflector proximate to the first surface of the major surface and oriented substantially perpendicular to the first surface of the major surface.

Abstract: A display that contains a backlight that incorporates an optical coating either on or above the light guide in order to reduce the appearance of optical hotspots on the display is provided. The optical coating can be patterned to correspond to the position of each light emitting diode in the display and can be made, as an example, from either reflective, diffusive or dichroic material. The coating can work to overcome the hotspots created by insufficient light mixing distance in the backlight.

Abstract: Quantum dot backlights for use in displays and processes for controlling the dimming of quantum dot backlights are provided. The backlight can include an LED (e.g., a blue LED) configured to emit a light through a sheet of quantum dots. The quantum dots can be configured to emit colored light (e.g., red and green light) in response to the light emitted from the LED. To control the relative luminance of the LED, the backlight can be controlled through the use of current dimming to adjust the brightness of the LED at high relative luminance settings to increase the light output efficiency and can include the use of pulse width modulation to adjust the brightness of the LED at low relative luminance settings to reduce the amount of wavelength shift experienced by the LED.

Abstract: A display device is provided. The display device includes a light source emitting a blue light and a light emitting layer including a first group of red quantum dots and a second group of green quantum dots. The light emitting layer is configured to absorb a first portion of the blue light from the light source to emit red light and green light and to transmit a second portion of the blue light. The display device also includes a dichroic filter layer configured to reflect a portion of the transmitted second portion of the blue light such that the reflected portion of the blue light is recycled in the light emitting layer and to transmit a remaining portion of the transmitted second portion of the blue light to output a white light.

Abstract: An edge-lit backlight unit for displays is provided. In one embodiment, the backlight may include a light guide configured to receive light from a light source along a first lateral edge. The received light propagates towards a second opposite lateral edge. The backlight unit may include an arrangement of light-extracting elements configured to extract a portion of the propagating light and to allow the remaining portion to reach the second edge. In one embodiment, a specular reflector disposed at the second edge causes the light reaching the second edge to retro-propagate back towards the first edge. In certain embodiments, the retro-propagating light may be between approximately 5 to 35 percent of the total light received by the light guide. The retro-propagating light may be extracted by multiple light-extracting elements and mixed with the extracted propagating light to provide improved color uniformity along an axis of the display.

Abstract: Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode (LED) based backlight. In one embodiment, the backlight may include two or more groups of LEDs, each driven at a respective driving strength. Each group may include LEDs of a different chromaticity, and the respective driving strengths may be adjusted, for example, by varying the duty cycles, to maintain the target white point. To ensure that the white point may be maintained over an operational temperature range of the backlight, the LEDs may be selected so that the chromaticities of each group of LEDs are separated by at least a minimum chromaticity difference. Further, the LEDs may be selected so that at the equilibrium temperature of the backlight, the LEDs may produce the target white point when driven at substantially equal driving strengths.

Abstract: A solid state lighting unit includes a plurality of solid state lighting tiles including a planar surface and a plurality of solid state light sources on the planar surface. The lighting unit includes a plurality of bar support members. Respective ones of the bar support members include at least two of the plurality of tiles affixed thereon to form respective bar assemblies, and respective ones of the solid state light sources on the solid state lighting tiles of a bar assembly are electrically connected in series so as to be simultaneously energized upon application of a voltage thereto. Methods of forming a solid state lighting unit are also disclosed.

Abstract: A method of calibrating a lighting panel including a plurality of segments, a respective segment configured to emit a first color light and a second color light in response to pulse width modulation control signals having respective duty cycles, includes activating the plurality of segments to simultaneously emit the first and second colors of light. A combined light output for the plurality of segments is measured at a measurement location to obtain aggregate emission data. Separate emission data for the first and second colors of light is determined based on the aggregate emission data. For example, the separate emission data for the first and second colors of light may be derived based on extrapolation of the aggregate emission data and expected emission data for the first and second colors of light. Related calibration systems are also discussed.

Abstract: Provided are methods and apparatus for combining light emitters and devices including the same. Embodiments include methods of selecting combinations of multiple light emitters that are grouped into multiple bins. The multiple bins correspond to multiple emitter group regions in a multiple axis color space and multiple luminosity ranges. Such methods may include prioritizing multiple combinations of light emitters from at least two of the bins, each of the combinations including chromaticity values corresponding to a desired color region and a luminosity value corresponding to a specified luminosity range.

Abstract: Provided are methods and apparatus for combining light emitters and devices including the same. Embodiments include methods of selecting combinations of multiple light emitters that are grouped into multiple bins. The multiple bins correspond to multiple emitter group regions in a multiple axis color space and multiple luminosity ranges. Such methods may include prioritizing multiple combinations of light emitters from at least two of the bins, each of the combinations including chromaticity values corresponding to a desired color region and a luminosity value corresponding to a specified luminosity range.