Abstract: In a display system having pixels made up of electroluminescent devices (ELDs) of three or more basis colors, a control circuit receives for each pixel a specification of a desired color to be displayed on the pixel, and determines a required driving voltage or electrical current for ELDs of each basis color, the required driving voltage or electrical current being determined from values of driving voltages or electrical currents associated with predetermined colors within the spectral locus or the purple line of human vision.

Abstract: A display structure for displaying an image represented by a number of pixels includes: (a) multiple switches; and (b) multiple display modules, with each display module having (i) a network interface which allows the display module to be interconnected by the switches in a programmable network configuration with the other display modules; and (ii) electroluminescent devices (ELDs) of three or more basis colors implementing one or more designated groups of pixels of the image. The display modules are synchronized internally and with each other using a precision timing protocol of the programmable network configuration. Each module may further include control logic circuitry for controlling the ELDs and an associated set of ELD drivers.

Abstract: In a display system having pixels made up of electroluminescent devices (ELDs) of three or more basis colors, a control circuit receives for each pixel a specification of a desired color to be displayed on the pixel, and determines a required driving voltage or electrical current for ELDs of each basis color, the required driving voltage or electrical current being determined from values of driving voltages or electrical currents associated with predetermined colors within the spectral locus or the purple line of human vision.

Abstract: A method computes drive currents for LEDs in a pixel of a signboard to achieve a desired color at a desired luminous intensity. This method is particular applicable to a signboard having pixels made up of four (4) or more primary colors. The method selects a number of colors within a color gamut, and for each selected color, the method computes drive currents for the LEDs of each basis color, such that the resulting luminous intensity of the selected color is maximum. Using the computed drive currents, the method then scales the drive currents to achieve the desired luminous intensity in the desired color. The drive currents may be computed, for example, using a constrained maximization technique, such as linear programming. In one embodiment, the drive currents for each selected color are computed subject to the constraint that none of the drive currents is negative, and that their total is less than a predetermined value.

Abstract: A method for use with an electronic signboard (e.g., an LED signboard) compensates psychovisual chromaticity shift due to ambient light. The method first measures a color of light reflected from the signboard. Based on the measurement a set of calorimetric equations defining the desired light to be perceived as being displayed by each pixel of the signboard are solved. The calorimetric equations are the additive color mixture of the ambient light and the light to be actually displayed by the pixel in the absence of ambient light. The calorimetric equations may be expressed in units of uniform color space. The solutions of the colorimetric equations are then used to control the light actually displayed by the pixel.

Abstract: A method displays a single image on a graphical display for diagnostic purpose, without interrupting an observer's perception of the display of a sequence of images. Under that method, a sequence of images is displayed on a graphical display, interrupted only by the diagnostic image that is displayed for a time period not longer than 30 milliseconds. The diagnostic image may be used, for example, for calibrating colors and luminances of pixels in the graphical display. Another use of the diagnostic image may be, for example, determination of the ambient light reflected from the graphical display.

Abstract: A method to be used in a light emitting diode (LED) display provides a fault-healing capability. The method is applicable to a display having pixels made up of LEDs of four or more primary colors. For each pixel, the method receives a signal specifying a light intensity and a color to be displayed and detects if a fault exists in an LED of one or more of the primary colors. When no fault is detected, the LEDs of the pixel are driven with currents to achieve the specified light intensity and color. Otherwise, the LEDs of the pixel are driven in the primary colors that are without fault, using a combination of currents to achieve the specified light intensity and color. The combination of currents is derived by finding a position of the specified color in a chromaticity diagram and, using that position, deriving the currents to drive the LEDs in the primary colors without fault.

Abstract: An apparatus dynamically circumvents faults in the light emitting diodes (LEDs) of a pixel in a graphical display. The LEDs are organized into groups of one or more LEDs. The apparatus includes drivers for generating a current to an associated group of LEDs of the pixel and fault detectors associated with each group of LEDs. The drivers may be driven, for example, by pulse-modulated signals specifying average currents for the groups of LEDs. The fault detectors each detect fault in an associated group of LEDs and asserts a fault signal when a fault is detected. In addition, an encoder is provided to receive the fault signals from the fault detectors and to provide signals encoding the faults detected and identifying the associated groups of LEDs. A controller that receives the encoded signals may adjust the driver signals for the groups of LEDs for which no fault is detected, in order to compensate for the detected faults.

Abstract: A graphical display includes multiple networked modules for controlling different group of pixels in the graphical display. In one embodiment, each module includes a network interface for receiving data and control signals, LED drivers for the pixels in the portion of the graphical display, and a control circuit that controls the currents in the LEDs in accordance with the control and data signals received. Memory modules may be provided to store data and programs for the control circuit. The network interfaces of the modules may comply with an industry standard computer network protocol.

Abstract: A display controller having only three color channels per pixel is used to control a display system having four or more color channels. Mapping of the possible luminance values for each color channel of each pixel to the 2n intervals represented by the n bits in each color channel are provided according to a function that is based on human color perception, so as not to generate artifacts.

Abstract: A method is applicable to a pixel of a graphical display that is formed by LEDs or LED strings, with the colors that can be displayed by the pixel (i.e., the color gamut) defined by an LED drive specification matrix A. The method displays a desired color at a chromaticity coordinates (xn, yn) and a luminous intensity Y by carrying out: (a) finding a maximum luminous intensity ? and the associated LED drive vector {circumflex over (b)} for each of a collection of sample colors in the color gamut using a mathematical programming technique; and (b) calculating the LED drive vector for the desired color; and (c) displaying the color on the pixel using the calculated drive vector. In one implementation, the calculated LED drive vector is scaled using the expression b ^ ? min ( Y Y ^ , 1 ) . (b) based on we sample colors.

Abstract: A method is applicable to a pixel of a graphical display that is formed by LEDs or LED strings, with the colors that can be displayed by the pixel (i.e., the color gamut) defined by an LED drive specification matrix A. The method displays a desired color at a chromaticity coordinates (xn, yn) and a luminous intensity Y by carrying out: (a) finding a maximum luminous intensity ? and the associated LED drive vector {circumflex over (b)} for each of a collection of sample colors in the color gamut using a mathematical programming technique; and (b) calculating the LED drive vector for the desired color; and (c) displaying the color on the pixel using the calculated drive vector. In one implementation, the calculated LED drive vector is scaled using the expression b ^ ? min ( Y Y ^ , 1 ) . (b) based on we sample colors.

Abstract: A method maps a color specified using a smaller color gamut to a larger color gamut. Under that method, a map in a chromaticity diagram is constructed that provides a direction and a magnitude for a unit change in chroma for a specified pixel value in the chromaticity diagram. Using the magnitude and direction in the map, the specified color is mapped to a new pixel value corresponding to a predetermined shift in chromaticity. Preferably, the new pixel value preserves the hue of the specified color, and its luminance related to that of the specified color. Also, the new pixel value preferably has a greater color saturation than the specified pixel value.

Abstract: An enclosure is provided for housing pixels of a graphical display. The enclosure provides one or more laminar structures at a first surface of the enclosure. The laminar structure may be made up of a first material of a predetermined thickness at the first surface and a second material in sufficiently close proximity with the first material to allow heat conduction. The second material preferably has a thermal conductivity greater than the thermal conductivity of the first material. Thermal conductors are provided in or attached to the second material in the laminar structure to conduct heat to a second surface of the enclosure. The first material may be, for example, a polymer. The second material may be, for example, a heat wick, a metal mesh or heat pipes. The second surface may be cooled by an air stream, which may also reduce humidity at the surface.

Abstract: A display controller having only three color channels per pixel is used to control a display system having four or more color channels. Mapping of the possible luminance values for each color channel of each pixel to the 2n intervals represented by the n bits in each color channel are provided according to a function that is based on human color perception, so as not to generate artifacts.

Abstract: An enclosure is provided for housing pixels of a graphical display. The enclosure provides one or more laminar structures at a first surface of the enclosure. The laminar structure may be made up of a first material of a predetermined thickness at the first surface and a second material in sufficiently close proximity with the first material to allow heat conduction. The second material preferably has a thermal conductivity greater than the thermal conductivity of the first material. Thermal conductors are provided in or attached to the second material in the laminar structure to conduct heat to a second surface of the enclosure. The first material may be, for example, a polymer. The second material may be, for example, a heat wick, a metal mesh or heat pipes. The second surface may be cooled by an air stream, which may also reduce humidity at the surface.

Abstract: An enclosure is provided for housing pixels of a graphical display. The enclosure provides one or more laminar structures at a first surface of the enclosure. The laminar structure may be made up of a first material of a predetermined thickness at the first surface and a second material in sufficiently close proximity with the first material to allow heat conduction. The second material preferably has a thermal conductivity greater than the thermal conductivity of the first material. Thermal conductors are provided in or attached to the second material in the laminar structure to conduct heat to a second surface of the enclosure. The first material may be, for example, a polymer. The second material may be, for example, a heat wick, a metal mesh or heat pipes. The second surface may be cooled by an air stream, which may also reduce humidity at the surface.

Abstract: An advertising support system includes an operation center, numerous display systems and one or more client services systems. The operation center is a platform that provides a collection of services and capabilities. For example, the operation center is responsible for assuring that the content is displayed on the display systems at required times and locations. The system may accommodate multiple operation centers in multiple geographical locations to provide failure recovery and to provide services over geographically diverse locations. A variety of services are provided by the operation center to support its operations and the display systems. For example, the operation center populates and maintains a current and archival database, which includes status, content, fault and maintenance logs, and other data of display systems. Numerous services may be provided through the client services systems.

Abstract: An enclosure is provided for housing pixels of a graphical display. The enclosure provides one or more laminar structures at a first surface of the enclosure. The laminar structure may be made up of a first material of a predetermined thickness at the first surface and a second material in sufficiently close proximity with the first material to allow heat conduction. The second material preferably has a thermal conductivity greater than the thermal conductivity of the first material. Thermal conductors are provided in or attached to the second material in the laminar structure to conduct heat to a second surface of the enclosure. The first material may be, for example, a polymer. The second material may be, for example, a heat wick, a metal mesh or heat pipes. The second surface may be cooled by an air stream, which may also reduce humidity at the surface.

Abstract: The present invention relates to a light-emitting diode (“LED”) display apparatus used for a display such as a type of standing signboard. The light-emitting diode display is comprised of light-emitting diodes which use a plurality of colors, including blues, reds and greens, arranged in a specific pattern such as a matrix pattern. The display is appropriate for displaying either a moving or a stationary graphical image by powering the LEDs to combine to produce specific colors.