Reflector providing particularly high reflectance in an intended viewing angle and reflection type liquid crystal display device using the same

• US 6,750,930 B2
• Filed: 06/29/2001
• Issued: 06/15/2004
• Est. Priority Date: 07/03/2000
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Omote, Kenji, Kano, Mitsuru, Moriike, Tatsuya, Yoshii, Katsumasa
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): NGUYEN, HOAN C
• Application Number:
  US09/896,165
• Publication Number:
  US 20020030774A1
• Time in Patent Office: 1,082 Days
• Field of Search: 349/113, 359/859, 359/869, 362/347
• US Class Current: 349/113
• CPC Class Codes: G02B 5/0215 the surface having a regular structure
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0257 creating an anisotropic diffusion characteristic, i.e. distributing output differently in two perpendicular axes
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605

Abstract

A reflector and reflector-type LCD suppresses inter-object reflection over a wide angle, and provides particularly high reflectance in an intended range of viewing angle. The reflector includes a plurality of concave portions with an inclination angle (an angle between a plane tangential to a point on a concave surface and the surface of the base material) that is maximum on a side portion of the curved surface. The concave portions may also be formed such that an inner surface of each of the concave portions include a peripheral curved surface and a bottom curved surface are continuously connected to each other. The peripheral curved surface and the bottom curved surface are interposed partial spheres having different radii and non-collinear normal lines from the surface of each sphere.

Claims

1. A reflector, comprising a plurality of light-reflective concave portions formed on a surface of a base material, each of the concave portions is a non-spherical concave surface, being formed such that an inclination angle of the concave portion at a periphery thereof has a maximum value, said maximum value of the inclination angle being that of at least a first point along the periphery having a larger inclination angle than the inclination angle of a second point along the periphery;

the periphery being formed by an intersection of the concave surface and the surface of the base material and having a curvilinear form; and

wherein the inclination of the concave portion is measured as an absolute value of an angle with respect to the surface of the base layer of a plane tangent to the concave portion.

2. The reflector according to claim 1, wherein the concave surface of each of the concave portions has a single minimal point (a point where the inclination angle becomes zero).

3. The reflector according to claim 1, wherein the maximum inclination angle along the periphery is in a range of 2°

to 80°

.

4. The reflector according to claim 1, wherein the maximum inclination angle along the periphery is in a range of 4°

to 35°

.

5. The reflector according to claim 1, wherein the plurality of the concave portions are formed randomly with a depth thereof ranging from 0.1 μ

m to 3 μ

m.

6. The reflector according to claim 1, wherein each of the plurality of the concave portions are arranged irregularly adjacent to each other.

7. The reflector according to claim 1, wherein the plurality of the concave portions are formed so that the side portion having the maximum inclination angle of the concave surface along the periphery is aligned in a particular direction.

8. A reflection type liquid crystal display device, wherein the reflector according to claim 1 is mounted therein.

9. The reflection type liquid crystal display device according to claim 8, wherein the reflector is formed so that the side portion having the maximum inclination angle along the periphery of the concave surface of each of the plurality of the concave portions is aligned in a certain direction and is mounted so that the side portion having the maximum inclination angle of the concave surface of each of the plurality of the concave portions is disposed on a side opposing a viewpoint of an observer.

10. A reflector, comprising:

a plurality of concave portions formed on a reflector surface, an inner surface of each of the concave portions including a bottom curved surface and a peripheral curved surface, the peripheral curved surface being a part of a first sphere having a first radius, the bottom curved surface being a second sphere having a second radius different from the first radius, and the bottom curved surface being located within the peripheral curved surface, wherein the first radius is smaller than the second radius, and a normal line extending from a center of the first sphere to the reflector surface and a normal line extending from a center of the second sphere to the reflector surface are not collinear.

11. The reflector according to claim 10, wherein the normal lines extending from the respective centers of the first sphere and the second sphere to the reflector surface are spaced apart from each other in a range of 0.1 μ

m to 10 μ

m.

12. The reflector according to claim 10, wherein an inclination angle of the peripheral curved surface is set in a range of 10°

to 35° and

−

35°

to −

10°

, and an inclination angle of the bottom curved surface is in a range of 4°

to 17° and

−

17°

to −

4°

.

13. The reflector according to claim 10, wherein the plurality of concave portions are formed randomly with the depth thereof ranging from 0.1 μ

m to 3 μ

m.

14. The reflector according to claim 10, wherein the plurality of concave portions are formed so that they are continuously connected to each other.

15. The reflector according to claim 10, wherein the plurality of concave portions are formed along with many grooves on the reflector surface.

16. A reflection type liquid crystal display device, wherein the reflector according to claim 10 is mounted therein.