Color filter registered reflective display

• US 10,304,394 B2
• Filed: 10/07/2015
• Issued: 05/28/2019
• Est. Priority Date: 10/08/2014
• Status: Active Grant

• Current Assignee: WUXI Clearink Limited
• Original Assignee: Clearink Displays, Inc.
• Inventors: Whitehead, Lorne A.
• Primary Examiner(s): Davis, Tony O
• Application Number:
  US15/509,676
• Publication Number:
  US 20170287406A1
• Time in Patent Office: 1,329 Days
• CPC Class Codes: G02B 26/023 comprising movable attenuating elements, e.g. neutral density filters
• CPC Class Codes: G02B 5/136 plural reflecting elements forming part of a unitary body G02B5/124 takes precedence
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/16761 Side-by-side arrangement of working electrodes and counter-electrodes
• CPC Class Codes: G02F 1/1677 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 1/1681 having two or more microcells partitioned by walls, e.g. of microcup type
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167

Abstract

A high efficiency, long life, video rate, electrophoretic display comprises fluid containing sub-pixel structures that are periodic, and aligned with a color filter array. A fluid comprising of electrophoretically mobile particles is compartmentalized at the size scale of the individual filters (one per filter) such that the particles may be moved to either allow light to be returned through the same filter back towards the viewer by total internal reflection (TIR) or conventional reflection to create a light state or to be absorbed by the particles to create a dark state. High reflectance is achieved through the use of structures that avoid ITO layers in the light path and reflecting most light, by virtue of a dual control of light by TIR and transmission to a reflector. In one embodiment the structures are in the shape of truncated pyramids.

Claims

1. A reflective image display, comprising:

a pixel array having a plurality of color filters;

a front electrode;

a rear electrode, the front and the rear electrode forming a gap therebetween;

a first and a second convexly-protruding light-directing structures positioned between the rear electrode and the plurality of color filters; and

wherein the first and the second convexly-protruding light-directing structures are configured to capture a light ray coming through a first of the plurality of color filters and to one of substantially absorb the incoming light ray or to substantially reflect the incoming light ray through the first of the plurality of color filters;

wherein at least a portion of the rear electrode is positioned between the first and the second convexly-protruding light-directing structures.

2. The display of claim 1, further comprising a plurality of electrophoretic particles movable between the first and the second electrode as a function of a differential bias applied to the first and the second electrodes.

3. The display of claim 1, wherein the first of the plurality of color filters, the front electrode, a portion of the first convexly-protruding light-directing structure, and a portion of the second convexly-protruding light-directing structure define a sub-pixel structure.

4. The display of claim 3, wherein at least one of the first convexly-protruding light-directing structure or the second convexly-protruding light-directing structure comprises a portion of a pyramid or a cylindrical structure configured to direct the incoming light ray within the sub- pixel structure.

5. The display of claim 3, wherein the front electrode defines a contiguous surface at the sub-pixel structure.

6. The display of claim 3, wherein the front electrode defines a dis-contiguous surface between two adjacent sub-pixel structures.

7. The display of claim 3, wherein the first convexly-protruding light directing structure is registered with at least one of the plurality of color filters.

8. The display of claim 1, wherein the first convexly-protruding light-directing structure and the second convexly-protruding light-directing structure are aligned with opposing ends of the first color filter.

9. The display of claim 1, wherein the first convexly-protruding light-directing structure further comprises a reflective coating.

10. A method for displaying a reflective image, the method comprising:

filtering an incoming light ray through a first of a plurality of color filters of a pixel to provide a filtered ray;

receiving the filtered ray at a first structure of a structure pair and directing the filtered ray to a second structure of the structure pair, the structure pair comprising a first and a second convexly-protruding light-directing structures separated by a span; and

substantially reflecting at least a portion of the filtered ray received at the second structure of the structure pair through the first of the plurality of color filters.

11. The method of claim 10, further comprising receiving the incoming light ray at an outward transparent sheet supporting the plurality of color filters.

12. The method of claim 10, further comprising absorbing a portion of the filtered ray at one of the first or the second structure of the structure pair.

13. The method of claim 12, further comprising driving a plurality of electrophoretic particles to one or more of the first or the second structure to absorb a portion of the filtered ray.

14. The method of claim 12, further comprising driving a plurality of electrophoretic particles to the first structure to absorb a portion of the filtered ray.

15. The method of claim 12, further comprising driving a plurality of electrophoretic particles to the second structure to absorb a portion of the filtered ray.

16. The method of claim 12, further comprising driving a plurality of electrophoretic particles to a span between the first and the second structure to absorb a portion of the filtered ray.

17. A computer-readable non-transitory storage medium that contains instructions, which when executed by one or more processors result in performing operations comprising:

filtering an incoming light ray through a first of a plurality of color filters of a pixel to provide a filtered ray;

receiving the filtered ray at a first structure of a structure pair and directing the filtered ray to a second structure of the structure pair, the structure pair comprising a first and a second convexly-protruding light-directing structures separated by a span; and

substantially reflecting at least a portion of the filtered ray received at the second structure of the structure pair through the first of the plurality of color filters.

18. The medium of claim 17, further comprising receiving the incoming light ray at an outward transparent sheet supporting the plurality of color filters.

19. The method of claim 17, further comprising absorbing a portion of the filtered ray at one of the first or the second structure of the structure pair.

20. The method of claim 19, further comprising driving a plurality of electrophoretic particles to one or more of the first or the second structure to absorb a portion of the filtered ray.

21. The method of claim 19, further comprising driving a plurality of electrophoretic particles to the first structure to absorb a portion of the filtered ray.

22. The method of claim 19, further comprising driving a plurality of electrophoretic particles to the second structure to absorb a portion of the filtered ray.

23. The method of claim 19, further comprising driving a plurality of electrophoretic particles to a span between the first and the second structure to absorb a portion of the filtered ray.