Electrodes for liquid crystal cells

• US 6,753,047 B1
• Filed: 06/07/2000
• Issued: 06/22/2004
• Est. Priority Date: 06/10/1999
• Status: Expired due to Fees

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Athey, Patricia Ruzakowski
• Primary Examiner(s): Pyon, Harold
• Assistant Examiner(s): HON, SOW FUN
• Application Number:
  US09/589,469
• Time in Patent Office: 1,476 Days
• Field of Search: 428/1.21, 428/1.5, 428/1.51, 428/1.62, 428/432, 428/472, 428/701, 428/702, 428/697, 428/689, 349/139, 349/147, 359/359, 359/360, 359/580, 359/589
• US Class Current: 428/1.21
• CPC Class Codes: C09K 2323/021 Inorganic, e.g. glass or silicon oxide
• CPC Class Codes: C09K 2323/061 Inorganic, e.g. ceramic, metallic or glass
• CPC Class Codes: G02F 1/133784 by rubbing
• CPC Class Codes: G02F 1/133796 having conducting property
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making

Abstract

Electrodes for liquid crystal cells include a substrate e.g. glass having a conductive and alignment coating e.g. a fluorine doped tin oxide coating. After a conductive coating is deposited on the substrate the surface is cleaned and wiped unidirectionally with a solvent saturated cloth for a predetermined number of times. The electrode prepared in the above manner eliminates the need for the polyimide layer over a conductive coating and heat treatment of the polyimide layer.

Claims

1. A liquid crystal cell comprising:

a sealed compartment;

a liquid mixture in the compartment, the liquid mixture comprising a liquid crystal and a dichroic dye;

a pair of electrodes having surface portions of the electrodes contacting the liquid mixture wherein the surface portions of the electrodes contacting the liquid mixture are both conducting and aligning surfaces comprising a tin oxide coating having a dopant material selected from the group consisting of fluorine, antimony, and mixtures thereof,

wherein alignment of the liquid crystals by the surface portions of the electrodes contacting the liquid mixture is observed by viewing the liquid mixture in an unbleached state through a linear polarizer with the position of the dichroic dye showing homogeneous alignment and direction of the liquid crystals, and

wherein at least one of the electrodes includes a gradient, mixed metal oxide of silicon oxide and tin oxide between the tin oxide coating and the substrate having a wt % of the silicon oxide that increases as the distance from the substrate decreases and a wt % of the tin oxide that decreases as the distance from the tin oxide coating increases.

2. The cell according to claim 1 wherein the sealed compartment comprises a pair of spaced glass substrates having portions of spaced adjacent surfaces of the substrates joined together to provide the sealed compartment and the dopant material is fluorine.

3. The cell according to claim 2 wherein one of the electrodes is supported by one of the glass substrates and the other electrode is supported by the other glass substrate.

4. The cell according to claim 3 wherein the electrodes are a pyrolytic coating.

5. The cell according to claim 1 wherein the sealed compartment includes at least one glass substrate and the pair of electrodes are two discrete and electrically isolated conducting areas on the at least one glass substrate.

6. The cell according to claim 1 wherein each of the electrodes comprise a coating stack having a silver layer between dielectric layers.

7. The cell according to claim 5 further including a primer layer between the silver layer and one of the dielectric layers.

8. The cell according to claim 7 wherein the coating is a sputter deposited coating.

9. The cell according to claim 1 wherein the dopant material is antimony.

10. The cell according to claim 1 wherein the dopant is a mixture of antimony and fluorine.

11. The cell according to claim 1 wherein the electrodes are a crystalline coating and the surface of the coating contacting the liquid mixture is a unidirectionally rubbed surface as referenced by the homogenous alignment and direction of the liquid crystals as indicated by the position of the dichroic dye.

12. The cell according to claim 1 wherein the sealed chamber includes a plastic substrate and the pair of electrodes comprise an ITO coating.

13. The cell according to claim 1 further comprising an AC voltage supply connected to the electrodes.

14. The cell according to claim 1 wherein the tin oxide coating and the mixed metal oxide layer are a pyrolytic coating and a pyrolytic mixed metal oxide layer, respectively.

15. The cell according to claim 1 wherein the aligning surface aligns the liquid crystals in a circular arrangement.

16. The cell according to claim 1 wherein the enclosure comprises a first plate having a major surface and a second plate having a major surface with the major surface of the plates facing one another, the first plate having the viewing area, wherein one of the electrodes is mounted on the major surface of the first plate and the other electrode is mounted on the major surface of the second plate and portion of each of the pair of electrode electrically accessible from outside the sealed chamber, and further comprising an AC voltage supply connected to the pair of electrodes wherein with the AC supply in the off position the cell has a light transmission defined as a first light transmission and with the AC supply in the on position the cell has a light transmission defined as a second light transmission wherein the first light transmission is different than the second light transmission.

17. The cell according to claim 16 wherein the plates are glass plates.