Manufacturing method and structure of slanting diffusive reflector

• US 6,692,902 B2
• Filed: 11/16/2001
• Issued: 02/17/2004
• Est. Priority Date: 11/16/2001
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chang, Shang-Wen, Wei, Ming-Dar, Wong, Yi-Chun
• Primary Examiner(s): Huff, Mark F.
• Assistant Examiner(s): Sagar, Kripa
• Application Number:
  US09/988,057
• Publication Number:
  US 20030096198A1
• Time in Patent Office: 823 Days
• Field of Search: 430/321, 430/322, 430/323, 430/325, 430/331, 430/396, 430/5, 359/580, 359/581, 359/585, 359/613
• US Class Current: 430/322
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G03F 7/0007 Filters, e.g. additive colour filters; Components for display devices
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process

Abstract

A manufacturing method and structure of slanting diffusive reflectors simplifies their manufacturing process and reduces cost. A photo mask comprising a plurality of half-tone exposure units is used. A half-tone photolithography process is performed on the positive photoresist formed on a substrate. Only one exposure process and a suitable drying step are required to form a plurality of slants and rough astigmatisms on the slants. The size of the half-tone exposure units is randomly selected. Each half-tone exposure unit comprises a plurality of parallel transmitting strips or shadow strips. The pitch of the transmitting strips or the shadow strips in one half-tone exposure unit can be arbitrary. The width of the shadow strips is gradually changing from one side of the half-tone exposure unit to the other side.

Claims

1. A manufacturing method of slanting diffusive reflector comprises the following steps:

providing a substrate,

forming a positive or a negative photoresist on said substrate,

providing a photo mask with a plurality of half-tone exposure units, each said half-tone exposure unit comprises a plurality of parallel transmitting strips or shadow strips,

performing with said photo mask out of focus exposure and developing process, in order to simultaneously form a plurality of slants with bumps on said photoresist,

drying said photoresist, and

forming a high reflection metal layer on said photoresist.

2. The manufacturing method of slanting diffusive reflector of claim 1, wherein an edge of said slants is about 10-40 micrometer.

3. The manufacturing method of slanting diffusive reflector of claim 1, wherein a same pitch or arbitrary pitch is obtained between said shadow strips in each of said half-tone exposure units, and the width of said shadow strips gradually changes.

4. The manufacturing method of slanting diffusive reflector of claim 3, wherein a size of said shadow strips is randomly selected in a certain range.

5. The manufacturing method of slanting diffusive reflector of claim 4, wherein a pitch between said transmitting strips or shadow strips of said half-tone exposure units and the way how the width changes are randomly selected in said certain range.

6. The manufacturing method of slanting diffusive reflector of claim 5, wherein said certain range is a pixel range.

7. A manufacturing method of slanting diffusive reflector of claim 1, wherein said dry photoresist step comprises:

soft baking at 100-150°

C. for 5-30 minutes, and hard baking at about 220°

C. for one and a half hour.

8. The manufacturing method of slanting diffusive reflector of claim 1, wherein said high reflection metal layer is selected from the group of silver, aluminum and other high reflection metals.

9. The manufacturing method of slanting diffusive reflector of claim 1, wherein each said half-tone exposure units has a neighboring light transmitting area in the horizontal direction, the width of said light transmitting area is 1-3 micrometer.