Liquid-crystal display apparatus

• US 6,825,895 B2
• Filed: 03/15/2002
• Issued: 11/30/2004
• Est. Priority Date: 03/16/2001
• Status: Expired due to Fees

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Umemoto, Seiji, Abe, Hideo, Kinoshita, Ryoji, Nakano, Yuuki, Ariyoshi, Toshihiko
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): Kim, Richard H
• Application Number:
  US10/098,145
• Publication Number:
  US 20030038916A1
• Time in Patent Office: 991 Days
• Field of Search: 349/61-68, 362/31, 362/32
• US Class Current: 349/63
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133368 Cells having two substrates with different characteristics, e.g. different thickness or material
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133616 Front illuminating devices

Abstract

A liquid-crystal display apparatus having a liquid-crystal panel, the liquid-crystal panel including a lower transparent substrate having a transparent electrode on at least one of its opposite surfaces, an upper transparent substrate having a transparent electrode opposite to the transparent electrode of the lower substrate, and liquid crystal held between the lower substrate and the upper substrate, wherein the upper substrate is thicker than the lower substrate. Preferably, the thickness of the lower substrate is not larger than ⅔ as large as the thickness of the upper substrate in order to achieve reduction in thickness and weight more effectively.

Claims

1. A reflection type liquid-crystal display apparatus comprising:

a reflection type liquid-crystal display panel;

at least one illuminator; and

an optical path control layer;

wherein the liquid-crystal display panel comprises a liquid-crystal cell and a reflection layer, the liquid-crystal cell including a back side cell substrate, a visual side cell substrate, and a layer of liquid crystal, the back side cell substrate including a support substrate and an electrode provided on the support substrate, the visual side cell substrate including a transparent substrate and a transparent electrode provided on the transparent substrate, the transparent substrate in the visual side cell substrate being thicker than the support substrate in the back side cell substrate, the layer of liquid crystal being held between the back side cell substrate and the visual side cell substrate with their respective electrodes disposed opposite to each other, the reflection layer being provided at the back of the liquid-crystal layer in the liquid-crystal cell so that external light incident on an outer surface of the visual side cell substrate is reflected by the reflection layer and so that display light transmitted through the liquid-crystal layer is made to exit from the visual side cell substrate so as to be viewed, the illuminator being disposed on at least one of side surfaces of the visual side cell substrate, the optical path control layer having a thickness of in a range from 10 to 300 μ

m and provided with light exit portions on the outer surface side of the visual side cell substrate, the light exit portions including optical path changing slopes by which light incident on the side surface through the illuminator is reflected toward the back side cell substrate, each of the optical path changing slopes being inclined at an inclination angle of from 35 to 48 degrees with respect to a reference plane of the liquid-crystal display panel.

2. A reflection type liquid-crystal display apparatus according to claim 1, wherein the support substrate in the back side cell substrate has a thickness of not larger than ⅔

as large as a thickness of the transparent substrate in the visual side cell substrate.

3. A reflection type liquid-crystal display apparatus according to claim 1, wherein the visual side cell substrate further includes a transparent layer with a refractive index lower than that of the transparent substrate, and the illuminator is disposed on the side surface of the visual side cell substrate.

4. A reflection type liquid-crystal display apparatus according to claim 1, wherein the liquid-crystal display panel further comprises one polarizer disposed on at least one of opposite surfaces of the liquid-crystal cell.

5. A reflection type liquid-crystal display apparatus according to claim 4, wherein the polarizer is interposed between the liquid-crystal cell and the optical path control layer.

6. A reflection type liquid-crystal display apparatus according to claim 5, wherein the liquid-crystal display panel further comprise a retarder plate interposed between the liquid crystal cell and the polarizer.

7. A reflection type liquid-crystal display apparatus according to claim 1, wherein the light exit portions in the optical path control layer comprise prism-like concave portions, and the optical path changing slopes in the light exit portions face the side surface on which the illuminator is disposed.

8. A reflection type liquid-crystal display apparatus according to claim 7, wherein each of the prism-like concave portions is shaped like an approximate triangle in cross sectional view of the optical path changing slopes.

9. A reflection type liquid-crystal display apparatus according to claim 7, wherein each of the prism-like concave portions comprise a groove continuous from one end to the other end of the optical path control layer, and each of the optical path changing slopes in the grooves is parallel or inclined to the side surface on which the illuminator is disposed.

10. A reflection type liquid-crystal display apparatus according to claim 7, wherein each of the prism-like concave portions comprise a small groove shaped like an approximate triangle in section and based on cross section of each of the optical path changing slopes, a length of a long side in each of the optical path changing slopes is not smaller than 5 times as large as the depth of the small groove, and the light exit portions contain a plurality of the small grooves distributed discontinuously and irregularly in a surface of the optical path control layer.

11. A reflection type liquid-crystal display apparatus according to claim 1, wherein the optical path control layer comprises a transparent sheet and bonded to the outer surface side of the visual side cell substrate by an adhesive layer having a refractive index higher than that of the transparent substrate in the visual side cell substrate.

12. A reflection type liquid-crystal display apparatus according to claim 1, wherein the illuminator is disposed on at least one of side surfaces of the transparent substrate of the visual side cell substrate.

13. A reflection type liquid-crystal display apparatus according to claim 1, wherein the visual side cell substrate further includes a low-refractive-index transparent layer interposed between the transparent substrate and the transparent electrode, the low-refractive-index transparent layer having a refractive index lower than that of the transparent substrate.