Reflection type display with front light

• US 6,323,919 B1
• Filed: 10/01/1999
• Issued: 11/27/2001
• Est. Priority Date: 10/02/1998
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Stanley Electric Company Limited
• Original Assignee: Sony Corporation (Sony Group Corp.), Stanley Electric Company Limited
• Inventors: Yang, Ying Bao, Ishige, Osamu, Oki, Yoji
• Primary Examiner(s): Dudek, James A.
• Assistant Examiner(s): SCHECHTER, ANDREW M
• Application Number:
  US09/411,702
• Time in Patent Office: 788 Days
• Field of Search: 349/63, 349/62, 349/65
• US Class Current: 349/63
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133616 Front illuminating devices

Abstract

A reflection type display having a front light comprises a light guide plate having a light incident portion to which the lights are introduced, a planar surface arranged on the surface facing said first substrate and a prismatic surface arranged on the other surface, said prismatic surface comprising pseudo-planar surfaces which are formed at an angle of approximately 0.5 to 3.5 degrees with said planar surface and are raised greater as being distanced away from said light incident portion and slanted surfaces which are formed at an angle of approximately 40 to 60 degrees with said planar surface and are descended greater as being distanced away from said light incident portion, said pseudo-planar surfaces and said slanted surfaces are arranged alternately to form multiple prisms.

Claims

1. A reflection type display comprising:

a panel with a display area which comprises a first transparent substrate arranged to face external incident lights, a second substrate opposing to and coupled with said first substrate through a gap therebetween, electro-optical material retained in the gap, and electrodes formed on at least one of said first and second substrates in order to apply electric field to said electro-optical material, wherein said electrodes form pixels arranged repeatedly in the first direction with a first pitch;

a light guide plate disposed outside of said first substrate on the light incident side, comprising a light incident portion to which the lights are introduced, and a pair of major surfaces including a planar surface facing to said first substrate and a prismatic surface on other side, said prismatic surface comprising pseudo-planar surfaces which are formed at an angle of approximately 0.5 to 3.5 degrees with said planar surface and which are raised greater as being distanced away from said light incident portion and slanted surfaces which are formed at an angle of approximately 40 to 60 degrees with said planar surface and which are descended greater as being distanced away from said light incident portion, and wherein said pseudo-planar surfaces and said slanted surfaces are arranged alternately to form multiple prisms arranged repeatedly at a second pitch which is different from said first pitch; and

a combination of a linear polarizing plate and a quarter wavelength plate disposed on said planar surface of said light guide plate.

2. The reflection type display according to claim 1, wherein said light guide plate comprises a transparent substrate which has a pair of surfaces which are parallel to each other and a plastic layer formed on said transparent substrate, said pseudo-planar surfaces and said slanted surfaces are formed on a surface of said plastic layer, and intersections of each pair of said slanted surface and adjacent pseudo-planar surface on side of said light incident portion form apex lines of the prisms whose heights from the surface of said transparent substrate are almost uniform as a whole.

3. The reflection type display according to claim 1, wherein intersections of each pair of said pseudo-planar surface and adjacent slanted surface on side of said light incident portion form bottom lines of the prisms whose depths from the apex lines become deeper as the bottom line is distanced away from said light incident portion.

4. The reflection type display according to claim 3, wherein the depths are so set that the strength of the lights reflected by said slanted surfaces and outgoing perpendicularly from said planar surface, at the farthest point of said planar surface from said light incident point is 1.3 to twice as large as that of the lights at the closest point on said planar surface from said light incident point.

5. The reflection type display according to claim 3, wherein the depths increase exponentially with respect to the distance from said light incident point.

6. The reflection type display according to claim 3, wherein the depth is in the range of 1 to 13 microns.

7. The reflection type display according to claim 1, wherein the pitch of said multiple prisms is in the range of 100 to 500 microns.

8. The reflection type display according to claim 3, wherein the pitch of said multiple prisms is in the range of 100 to 500 microns.

9. The reflection type display according to claim 1, wherein an area between adjacent positions of same phase relation of the prism with the pixel is at least about {fraction (2/13)} of the display area.