Electro-optic displays with color filter arrays for reducing visible texture patterns in displayed images

Abstract

A color electro-optic display includes a layer of electro-optic material, an array of pixel electrodes, and a color filter array (CFA). The electro-optic material layer has a light-transmitting electrode on a viewing side, the array of pixel electrodes is on the opposite side, and the color filter array is on the viewing side. The pixel electrodes drive selected portions of the electro-optic material between white and black optical states. The CFA includes an array of pixels, each of which has at least three color filter elements. Each color filter element is aligned with a different pixel electrode such that when an adjacent portion of the electro-optic material is driven to the white optical state, the color of any color filter element is visible, and when driven to the black optical state, it is invisible. The colors of the color filter elements have the same brightness or a difference of no more than 10 L* in brightness, to substantially eliminate visible CFA texture patterns in the displayed image.

Claims

1. A color electro-optical display, comprising: An electro-optic material layer having a viewing side facing a viewer; a light-transmitting electrode on the viewing side of the electro-optic material layer; an array of pixel electrodes on the electro-optic material layer, on the side opposite to the viewing side, each of the pixel electrodes in the array being independently addressable to apply a driving voltage to an adjacent portion of the electro-optic material layer associated therewith, to drive such a portion of the electro-optic material layer between a first substantially white optical state and a second substantially black optical state on the viewing side of the electro-optic material layer; and a color filter array disposed on the viewing side of the electro-optic material layer, the color filter array comprising an array of pixels, each of the pixels having at least three color filter elements, the at least three color filters... Each of the at least three color filter elements has a different color, wherein the different colors are red, green, and blue, and each of the at least three color filter elements is aligned with a different one in the array of pixel electrodes, such that when the pixel electrode aligned with any of the at least three color filter elements drives an adjacent portion of the electro-optic material layer to the first substantially white optical state, the color of the color filter element is visible to the viewer, and wherein when the pixel electrode aligned with any of the color filter elements drives an adjacent portion of the electro-optic material layer to the second substantially black optical state, the color of the color filter element is invisible to the viewer; When the adjacent portion of the electro-optic material layer is in the first white optical state, each of the red, green, and blue colors of the at least three color filter elements in the color filter array has a CIELAB brightness L* between 45L* and 55L*, and the red, green, and blue colors of the at least three color filter elements in the color filter array have the same brightness or a brightness difference of no more than 10L*, so as to substantially eliminate the visible color filter array texture pattern.

2. The color electro-optical display of claim 1, wherein the colors of the at least three color filter elements in the color filter array have a luminance contrast of less than 1.

6.

3. The color electro-optic display as claimed in claim 1, wherein the layers of the electro-optic material are monochromatic.

4. The color electro-optic display of claim 1, wherein the layer of the electro-optic material includes an encapsulated electrophoretic medium.

5. The color electro-optic display of claim 4, wherein the encapsulated electrophoretic medium comprises one electrophoretic medium encapsulated in a plurality of microcapsules or a plurality of microcups.

6. The color electro-optic display of claim 1, wherein the layer of electro-optic material comprises a plurality of charged pigment particles dispersed in a nonpolar solvent.

7. The color electro-optical display of claim 6, wherein the charged pigment particles comprise a plurality of black and white pigment particles.

8. The color electro-optic display of claim 1, wherein the electro-optic material layer is bistable.

9. The color electro-optical display of claim 1, wherein the colors of the at least three color filter elements each have a given ink concentration, configured to provide the same brightness, wherein each ink concentration is determined using a Kubelka-Munk model.

10. A method for constructing a color electro-optic display, comprising depositing a color filter array on an electro-optic display, wherein the electro-optic display includes: (a) a layer of electro-optic material having a viewing side for facing a viewer; (b) a light-transmitting electrode on the viewing side of the electro-optic material layer; and (c) an array of pixel electrodes on the electro-optic material layer on the side opposite to the viewing side, each of the pixel electrodes in the array being independently addressable to apply a driving voltage to an adjacent portion of the electro-optic material layer associated therewith to drive such portion of the electro-optic material layer between a first substantially white optical state and a second substantially black optical state at the viewing side of the electro-optic material layer; The color filter array is deposited on the viewing side of the electro-optic material layer. The color filter array includes an array of pixels, each pixel having at least three color filter elements. Each of the at least three color filter elements has a different color, wherein the different colors are red, green, and blue. Each of the at least three color filter elements is aligned with a different pixel in the pixel electrode array, such that when the pixel electrode aligned with any color filter element drives an adjacent portion of the electro-optic material layer to the first substantially white optical state, the color of the color filter element is visible to the viewer, and the color of the color filter element is visible to the viewer when any color filter element is aligned with the pixel electrode. When the pixel electrode aligned with the element drives one of the adjacent portions of the electro-optic material layer to the second substantially black optical state, the color of the color filter element is invisible to the viewer. When the adjacent portion of the electro-optic material layer is in the first white optical state, each of the red, green, and blue colors of the at least three color filter elements in the color filter array has a CIELAB brightness L* between 45L* and 55L*, and the red, green, and blue colors of the at least three color filter elements in the color filter array have the same brightness or a brightness difference of no more than 10L*, so as to substantially eliminate the visible color filter array texture pattern.

11. The method of claim 10, wherein the colors of the at least three color filter elements in the color filter array have a luminance contrast of less than 1.

6.

12. The method of claim 10, wherein the layer of the electro-optic material is monochromatic.

13. The method of claim 10, wherein the layer of the electro-optic material includes an encapsulated electrophoretic medium.

14. The method of claim 13, wherein the encapsulated electrophoretic medium comprises one electrophoretic medium encapsulated in a plurality of microcapsules or a plurality of microcups.

15. The method of claim 10, wherein the electro-optic material layer comprises a plurality of charged pigment particles dispersed in a nonpolar solvent.

16. The method of claim 15, wherein the charged pigment particles comprise a plurality of black and white pigment particles.

17. The method of claim 10, wherein the layers of the electro-optic material are bistable.

18. The method of claim 10, wherein the colors of the at least three color filter elements each have a given ink concentration, configured to provide the same brightness, wherein each ink concentration is determined using a Kubelka-Munk model.

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