Liquid crystal display device using a color-sequential method wherein the number of different colored LEDs is less than the number of primary colors used in the display
View Patent ↗A color Liquid Crystal display (LCD) device for displaying a color image using at least four different primary colors, the device including an array of Liquid Crystal (LC) elements, driving circuitry adapted to receive an input corresponding to the color image and to selectively activate the LC elements of the LC array to produce an attenuation pattern corresponding to a gray-level representation of the color image, and an array of color sub-pixel filter elements juxtaposed and in registry with the array of LC elements such that each color sub-pixel filter element is in registry with one of the LC elements, wherein the array of color sub-pixel filter elements comprises at least four types of color sub-pixel filter elements, which transmit light of the at least four primary colors, respectively.
1. A color Liquid Crystal Display (LCD) device for displaying a temporally-integrated color image comprising a sequence of at least four non-white primary color images, the device comprising:
an array of Liquid Crystal (LC) elements;
driving circuitry adapted to receive an input corresponding to each of said at least four primary color images and to selectively activate the LC elements of said LC array to produce attenuation patterns corresponding to gray-level representations of each of said at least four primary color images, respectively; and
an illumination system adapted to sequentially back-illuminate said LC array with light of at least four different primary colors corresponding to the colors of said at least four primary color images, wherein said illumination system comprises:
an array of at least three Light Emitting Diodes (LEDs) having at least three different colors, respectively, wherein the LED colors include at least red, blue, and green, and the number of LED colors in the array is less than the number of primary colors used in the primary color images,
illumination control circuitry adapted to selectively activate said array of LEDs to produce a sequence of at least four illumination patterns, each said illumination pattern having a color corresponding to each of said at least four different primary colors, respectively, wherein at least one of said at least four illumination patterns produces one of said primary colors by simultaneously activating at least two different colors of said LEDs, and
an optical arrangement which causes the at least four illumination patterns produced by said array of LEDs to back-illuminate said LC array with a generally spatially homogeneous light of said at least four, respective, primary colors,
wherein said driving circuitry and said illumination system are synchronized such that each said attenuation pattern is illuminated with light of the primary color corresponding to the respective primary color image, thereby producing a temporally-integrated image comprising the at least four primary color images, wherein the light produced by the LEDs to back-illuminate the LC array corresponds to the primary colors displayed to produce the temporally-integrated image.
2. A device according to claim 1 wherein said at least four primary color images comprise red, green, blue, and yellow images.
3. A device according to claim 1 wherein said at least four primary color images comprise red, green, blue, yellow, and cyan images.
4. A device according to claim 1 wherein said at least four primary color images comprise red, green, blue, yellow, cyan, and magenta images.
5. A system comprising:
an illumination module to sequentially produce light of at least four non-white primary colors, the illumination module comprising:
an array of at least three different color Light Emitting Diodes (LEDs), wherein the LED colors include at least red, blue, and green and wherein the number of LED colors in the array is less than the number of primary colors used in the primary color images; and
an illumination control module adapted to selectively activate said array of LEDs to produce a sequence of at least four illumination patterns, each said illumination pattern having a color corresponding to each of said at least four different primary colors,
wherein said sequence of illumination patterns comprises a sequence of at least four illumination patterns corresponding to said at least four different primary colors, respectively, and
wherein said illumination control module is programmed to simultaneously activate at least two of said at least three different color LEDs to produce at least one of said at least four illumination patterns, thereby producing a temporally-integrated image comprising the at least four primary color images, wherein the light produced by the LEDs to back-illuminate the LC array corresponds to the primary colors displayed to produce the temporally-integrated image.
6. The system of claim 5 comprising:
a display controller to receive image data representing a color image in terms of at least four primary colors and, based on said image data, to produce a light pattern corresponding to said color image by selectively controlling the path of light of said at least four primary colors.
7. The system of claim 5 comprising:
an optical arrangement to provide said display controller with a generally spatially homogeneous light of said at least four, respective, primary colors.
8. The system according to claim 5 , comprising at least four different color LEDs.
9. A method of displaying a temporally-integrated color image comprising a sequence of at least four non-white primary color images, the method comprising:
receiving an input corresponding to at least four primary color images, said at least four primary color images associated with a color image;
sequentially for each of said at least four primary color images, selectively activating liquid crystal (LC) elements of a liquid crystal display (LCD) device to produce an attenuation pattern corresponding to a gray-level representation of each of said at least four primary color images, respectively; and
sequentially for each of said at least four primary color images, back-illuminating the LC array with an illumination pattern of each of said at least four primary colors by selectively activating an array of at least three Light Emitting Diodes (LEDs) having at least three different colors including red, blue, and green, wherein the number of LED colors in the array is less than the number of primary colors used in the primary color images and wherein at least one of said primary colors is produced by simultaneously activating at least two different colors of said LEDs, and
wherein the steps of selectively activating the LED array and selectively activating the LC elements are synchronized such that each of said attenuation patterns is illuminated with light of the primary color created by the LED array corresponding to the respective primary color image, wherein the light produced by the LEDs to back-illuminate the LC array corresponds to the primary colors displayed to produce the temporally-integrated image.