Reflector, method for fabricating the same and reflective liquid crystal display device incorporating the same

• US 6,600,535 B1
• Filed: 02/25/1999
• Issued: 07/29/2003
• Est. Priority Date: 02/27/1996
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fujii, Akiyoshi, Tsuda, Kazuhiko, Kimura, Naofumi, Ban, Mariko, Nakamura, Kozo, Nakamura, Masako, Itoh, Yasuhisa
• Primary Examiner(s): Ton, Toan
• Application Number:
  US09/258,250
• Time in Patent Office: 1,615 Days
• Field of Search: 349/113, 349/187, 349/130
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence

Abstract

A reflector includes a substrate, a plurality of convex/concave portions formed on the substrate, and a thin reflective film formed over the convex/concave portions. When light is incident upon the reflector from a certain direction, an intensity of reflected light in a viewing angle range of about −45° to +45° with respect to a regular reflection direction of the incident light 10 is about 60% or more of an intensity of light which is incident upon a standard white plate from a direction inclined by about 30° from a direction normal to the plate and is reflected to the direction normal to the plate.

Claims

1. A method for fabricating a reflector comprising a substrate, a plurality of convex/concave portions formed on the substrate, and a thin reflective film formed over the convex/concave portions, the method comprising the steps of:

forming a first photosensitive resin layer on the substrate;

performing a photolithography process to form a plurality of cylindrical depressions in the first photosensitive resin layer, wherein the first photosensitive resin layer has continuity around each of the plurality of cylindrical depressions;

heating the plurality of cylindrical depressions to form the convex/concave portions in the first photosensitive resin layer on the substrate; and

forming the thin reflective film over the convex/concave portions.

2. A method for fabricating a reflector according to claim 1, further comprising a step of forming a second photosensitive resin layer on the substrate after the step of heating.

3. A method for fabricating a reflector according to claim 1, wherein, when light is incident upon the reflector at a first incident angle with respect to a normal direction thereof, an intensity of the light which is reflected by the reflector toward a direction range of about −

45°

to +45°

with respect to a regular reflection direction of the light is about 60% or more of a reference intensity, where the reference intensity is an intensity of light which is incident upon a standard white plate at a second incident angle with respect to a normal direction thereof, the first incident angle and the second incident angle being substantially equal to each other.

4. A method for fabricating a reflector according to claim 1, wherein:

each of the convex/concave portions at least partially includes a continuous curved surface; and

a total area of the portions of the substrate whose inclination at a surface of the reflector is less than 2°

accounts for about 40% or less with respect to a total area of the substrate.

5. A method for fabricating a reflector according to claim 1, wherein the depressions are circular.

6. A method for fabricating a reflector according to claim 1, wherein the step of heating, the first photosensitive resin layer fills upon the corners and bottoms of the plurality of cylindrical depressions.

7. A method for fabricating a reflector comprising a substrate, a plurality of convex/concave portions formed on the substrate, and a thin reflective film formed over the convex/concave portions, the method comprising the steps of:

forming a first photosensitive resin layer on the substrate;

performing a photolithography process to form a plurality of cylindrical depressions in the first photosensitive resin layer, wherein the first photosensitive resin layer has continuity around each of the plurality of cylindrical depressions, and wherein each of the plurality of cylindrical depressions is defined to extend a predetermined distance below the photosensitive resin layer;

heating the plurality of cylindrical depressions to form the convex/concave portions in the first photosensitive resin layer on the substrate; and

forming the thin reflective film over the convex/concave portions.