LIQUID CRYSTAL DISPLAY DEVICE

• US 20080186437A1
• Filed: 01/22/2008
• Published: 08/07/2008
• Est. Priority Date: 07/22/2005
• Status: Active Grant

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Kunimine, Megumi, Takahashi, Hitoshi, Fujiwara, Teruo
• Granted Patent: US 7,692,736 B2
• Time in Patent Office: Days
• US Class Current: 349/117
• CPC Class Codes: G02F 1/133368 Cells having two substrates with different characteristics, e.g. different thickness or material
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133633 using mesogenic materials
• CPC Class Codes: G02F 1/13471 in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells G02F1/13475 takes precedence
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 2413/01 Number of plates being 1

Abstract

A liquid crystal display device eliminating an uneven display is presented.

A D-STN type liquid crystal display device has a compensation cell and a liquid crystal cell for display wherein a difference between the average thicknesses of at least two adjacent glass substrates among glass substrates existing in the compensation cell and the liquid crystal cell for display is 4 μm or more, and preferably not more than 50 μm.

Claims

1. In a D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display, said liquid crystal display device being characterized in that a difference between the average thicknesses of at least two adjacent glass substrates among glass substrates existing in the compensation cell and the liquid crystal cell for display is 4 μ

m or more.

2. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 1, wherein a difference between the average thicknesses of adjacent glass substrates among glass substrates existing in the compensation cell and the liquid crystal cell for display is 4 μ

m or more.

3. The liquid crystal display device according to claim 1, wherein in either combination of a frontside glass substrate and a backside glass substrate in the liquid crystal cell for display or a frontside glass substrate and a backside glass substrate in the compensation cell, a difference between the average thicknesses of glass substrates in combination is 4 μ

m or more.

4. The liquid crystal display device according to claim 1, wherein a difference between the average thicknesses of adjacent substrates is not more than 50 μ

m.

6. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 1, wherein a glass substrate constituting adjacent glass substrates in the compensation cell and the liquid crystal cell for display does not have a tilt of thickness difference of 0.1 μ

m/mm or more or a tilt of thickness difference of −

0.1 μ

m/mm or less at at least three consecutive points that are plotted arbitrarily at positions 2 mm away from each other in an arbitrary line in parallel to a long-side direction or a short-side direction of adjacent glass substrates in an overlapping state.

7. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 1, wherein in any combination among a frontside glass substrate and a backside glass substrate of the compensation cell, a backside glass substrate of the compensation cell and a frontside glass substrate of the liquid crystal cell for display, and a frontside glass substrate and a backside glass substrate of the liquid crystal cell for display, at least two values among T_1-2, T_2-3 and T_3-4 take at least 4 μ

m where T_1-2, T_2-3 or T_3-4 is a difference between average thicknesses of adjacent glass substrates.

8. The liquid crystal display device according to claim 7, wherein T_3-4 is at least 4 μ

m.

10. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 1, wherein a glass substrate constituting adjacent glass substrates does not have a specified portion in which a thickness difference at same positions in the adjacent glass substrates is 0.1 μ

m or less.

11. The liquid crystal display device according to claim 2, wherein a difference between the average thicknesses of adjacent substrates is not more than 50 μ

m.

12. The liquid crystal display device according to claim 3, wherein a difference between the average thicknesses of adjacent substrates is not more than 50 μ

m.

13. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 2, wherein a glass substrate constituting adjacent glass substrates in the compensation cell and the liquid crystal cell for display does not have a tilt of thickness difference of 0.1 μ

m/mm or more or a tilt of thickness difference of −

0.1 μ

m/mm or less at at least three consecutive points that are plotted arbitrarily at positions 2 mm away from each other in an arbitrary line in parallel to a long-side direction or a short-side direction of adjacent glass substrates in an overlapping state.

14. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 3, wherein a glass substrate constituting adjacent glass substrates in the compensation cell and the liquid crystal cell for display does not have a tilt of thickness difference of 0.1 μ

m/mm or more or a tilt of thickness difference of −

0.1 μ

m/mm or less at at least three consecutive points that are plotted arbitrarily at positions 2 mm away from each other in an arbitrary line in parallel to a long-side direction or a short-side direction of adjacent glass substrates in an overlapping state.

5. In a D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display, said liquid crystal display device being characterized in that a glass substrate constituting adjacent glass substrates in the compensation cell and the liquid crystal cell for display does not have a tilt of thickness difference of 0.1 μ

m/mm or more or a tilt of thickness difference of −

0.1 μ

m/mm or less at at least three consecutive points that are plotted arbitrarily at positions 2 mm away from each other in an arbitrary line in parallel to a long-side direction or a short-side direction of adjacent glass substrates in an overlapping state.

15. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 5, wherein in any combination among a frontside glass substrate and a backside glass substrate of the compensation cell, a backside glass substrate of the compensation cell and a frontside glass substrate of the liquid crystal cell for display, and a frontside glass substrate and a backside glass substrate of the liquid crystal cell for display, at least two values among T_1-2, T_2-3 and T_3-4 take at least 4 μ

m where T_1-2, T_2-3 or T_3-4 is a difference between average thicknesses of adjacent glass substrates.

16. The liquid crystal display device according to claim 15, wherein T_3-4 is at least 4 μ

m.

17. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 5, wherein a glass substrate constituting adjacent glass substrates does not have a specified portion in which a thickness difference at same positions in the adjacent glass substrates is 0.1 μ

m or less.

9. In a D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display, said liquid crystal display device being characterized in that a glass substrate constituting adjacent glass substrates does not have a specified portion in which a thickness difference at same positions in the adjacent glass substrates is 0.1 μ

m or less.

18. The D-STN type liquid crystal display device having a compensation cell and a liquid crystal cell for display according to claim 9, wherein a glass substrate constituting adjacent glass substrates does not have a specified portion in which a thickness difference at same positions in the adjacent glass substrates is 0.1 μ

m or less.