LCOS display with light absorbing material between pixels

Patent metadata

Field	Value
Publication number	US-11073709-B2
Application number	US-201816164469-A
Country	US
Kind code	B2
Filing date	Oct 18, 2018
Priority date	Oct 18, 2018
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

An example liquid crystal display device includes a circuit substrate, an array of conductive mirrors formed on the substrate, a light absorbing material disposed between the conductive mirrors, a transparent plate disposed over the array of conductive mirrors, and liquid crystal material disposed between the conductive mirrors and the transparent plate. The light absorbing material can also be disposed around the peripheral region of the array of the conductive mirrors. In an example display, the light absorbing material is black and/or has a light absorbing efficiency of at least fifty percent.

First claim

We claim:

1. A liquid crystal display device comprising:
a circuit substrate;
an array of individual conductive mirrors formed on said substrate, each of said individual conductive mirrors forming a part of a respective individual pixel of said liquid crystal display device wherein each of said individual conductive mirrors being configured to be driven independently;
a light absorbing material disposed between said conductive mirrors;
a transparent plate disposed over said array of conductive mirrors; and
liquid crystal material disposed between said conductive mirrors and said transparent plate; and wherein
said light absorbing material is formed directly on a surface of said circuit substrate;
said conductive mirrors are formed directly on said surface of said circuit substrate;
said light absorbing material and said array of said conductive mirrors each have a lowermost surface and an uppermost surface, said uppermost surfaces being further away from said surface of said circuit substrate than said lowermost surfaces; and
said uppermost surface of said light absorbing material and said uppermost surfaces of said conductive mirrors are coplanar.

2. The liquid crystal display device of claim 1 , wherein said light absorbing material is disposed around the peripheral region of said array of said individual conductive mirrors.

3. The liquid crystal display device of claim 1 , wherein said light absorbing material is black.

4. The liquid crystal display device of claim 1 , wherein said light absorbing material has a light absorbing efficiency of at least fifty percent.

5. The liquid crystal display device of claim 1 , wherein said light absorbing material is formed on said circuit substrate by a lithographic process.

6. The liquid crystal display device of claim 1 , further comprising a plurality of wire bond pads formed on said circuit substrate, said plurality of wire bond pads and said array of said individual conductive mirrors being coplanar and formed from the same material.

7. The liquid crystal display device of claim 1 , wherein said liquid crystal display device is a Liquid Crystal on Silicon (LCOS) device.

8. The liquid crystal display device of claim 1 , further comprising a first liquid crystal alignment layer formed over said array of individual conductive mirrors and over said light absorbing material.

9. The liquid crystal display device of claim 1 , further comprising:
a plurality of electrical bond pads; and wherein
said light absorbing material covers the entire top surface of said circuit substrate, except for top surfaces of said individual pixel mirrors and said electrical bond pads.

10. The liquid crystal display device of claim 1 , wherein said circuit substrate is a metal-oxide-semiconductor (MOS) circuit substrate.

11. The liquid crystal display device of claim 10 , wherein said circuit substrate is a complementary metal-oxide-semiconductor (CMOS) circuit substrate.

12. The liquid crystal display device of claim 1 , wherein:
said array of individual conductive mirrors includes a first conductive mirror and a second conductive mirror, said second conductive mirror disposed next to said first conductive mirror with no other conductive mirrors disposed therebetween;
said first conductive mirror includes a side surface extending from said uppermost surface of said first conductive mirror toward said circuit substrate;
said second conductive mirror includes a side surface extending from said uppermost surface of said second conductive mirror toward said circuit substrate; and
a first portion of said light absorbing material is disposed between said side surface of said first conductive mirror and said side surface of said second conductive mirror.

13. The liquid crystal display device of claim 12 , wherein:
said first portion of said light absorbing material is disposed to block incident light from impinging on said side surface of said first conductive mirror and to block light from impinging on said side surface of said second conductive mirror.

14. The liquid crystal display device of claim 12 , wherein:
said uppermost surface of said first conductive mirror has a first edge;
said uppermost surface of said second conductive mirror has a second edge, said first edge and said second edge defining a space between said first conductive mirror and said second conductive mirror;
said first portion of said light absorbing material is at least partially disposed between said space and said side surface of said first conductive mirror, and between said space and said side surface of said second conductive mirror.

15. The liquid crystal display device of claim 12 , wherein:
said uppermost surface of said first conductive mirror has a height relative to said circuit substrate;
said first portion of said light absorbing material has a height relative to said circuit substrate; and
said height of said uppermost surface of first conductive mirror and said height of said first portion of said light absorbing material are the same.

16. The liquid crystal display device of claim 12 , wherein:
said first portion of said light absorbing material has an uppermost surface; and
said uppermost surface of said first portion of said light absorbing material is coplanar with said uppermost surface of said first conductive mirror and said uppermost surface of said second conductive mirror.

17. The liquid crystal display device of claim 12 , wherein:
said first conductive mirror is disposed on an edge of said array of conductive mirrors;
said first conductive mirror includes a second side surface facing outwardly with respect to said array of conductive mirrors; and
said light absorbing material includes a second portion adjacent said second side surface of said first conductive mirror.

18. The liquid crystal display device of claim 17 , wherein:
said second portion of said light absorbing material has an uppermost surface; and
said uppermost surface of said second portion of said light absorbing material is coplanar with said uppermost surface of said first conductive mirror.

19. The liquid crystal display device of claim 17 , wherein said second portion of said light absorbing material continuously and completely surrounds said array of individual conductive mirrors.

20. The liquid crystal display device of claim 1 , wherein a respective portion of said light absorbing material is disposed between every pair of adjacent individual conductive mirrors of said array of individual conductive mirrors.

21. The liquid crystal display device of claim 1 , wherein:
said circuit substrate includes circuitry; and
each individual mirror of said array of individual conductive mirrors is disposed at least partially above said circuitry.

22. The liquid crystal display device of claim 1 , wherein said light absorbing material is disposed directly in gaps formed between said individual conductive mirrors.

Assignees

• Omnivision Tech Inc

Inventors

• Ko Pei-Wen
• Fan Chun-Sheng

Classifications

• G02F1/1352

  Light-reflecting layers · CPC title

• G02F1/133553

  Reflecting elements (associated to illuminating devices G02F1/133605) · CPC title

• G02F1/1343

  Electrodes {(reflective electrodes G02F1/133553)} · CPC title

• G02F1/136277

  formed on a semiconductor substrate, e.g. of silicon · CPC title

• G02F1/133314

  Back frames · CPC title