Liquid crystal on silicon (LCOS) display device having a uniform cell gap

• US 20050128173A1
• Filed: 12/15/2004
• Published: 06/16/2005
• Est. Priority Date: 12/15/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Su-gun, Shin, Su-ho, Cho, Jin-woo, Wang, Jong-min, Booh, Seong-woon
• Granted Patent: US 7,535,446 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133368 Cells having two substrates with different characteristics, e.g. different thickness or material
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 2203/18 adaptive optics, e.g. wavefront correction

Abstract

A liquid crystal on silicon (LCOS) device includes a wafer, glass, and walls formed at opposite ends of an upper surface of the wafer to define a predetermined cell gap between the glass and the wafer. A thin piezo-electric layer is attached onto a surface of the wafer and an electrode is applied with external power to expand and/or contract the thin piezo-electric layer. The LCOS device further includes a voltage detection unit for detecting a voltage generated by the deformation of the thin piezo-electric layer; and a feedback control unit for compensating for deformation of the thin piezo-electric layer according to the voltage detected by the voltage detection unit. The LCOS device achieves uniformity of the cell gap by adjusting the voltage level of the thin piezo-electric layer after bonding the wafer and the glass, and therefore, spacers are not required.

Claims

1. A liquid crystal on silicon (LCOS) display device comprising:

a wafer;

a glass;

walls formed between the glass and the wafer to define a cell gap;

a piezo-electric layer coupled to a surface of the wafer; and

an electrode being applied with an external power to at least one of expand and contract the piezo-electric layer.

2. The LCOS device as claimed in claim 1, wherein the piezo-electric layer is coupled to a lower surface of the wafer.

3. The LCOS device as claimed in claim 1, further comprising:

a voltage detection unit which detects a voltage generated by deformation of the piezo-electric layer; and

a feedback control unit which compensates for the deformation of the piezo-electric layer according to the voltage detected by the voltage detection unit.

4. The LCOS device as claimed in claim 1, wherein the walls are formed at opposite ends of an upper surface of the wafer.

5. A method of adjusting a cell gap of a liquid crystal on silicon display device having a piezo-electric layer, the method comprising:

detecting a voltage generated by deformation of the piezo-electric layer;

supplying a feedback voltage to an electrode connected to the piezo-electric layer according to the voltage detected.