Light Diffusion Plate and Backlight Device

• US 20090059564A1
• Filed: 09/27/2006
• Published: 03/05/2009
• Est. Priority Date: 09/28/2005
• Status: Abandoned Application

• Current Assignee: ZEON Corporation
• Original Assignee: ZEON Corporation
• Inventors: Muraoka, Noboru, Tsukada, Keisuke, Hayashi, Masahiko
• Application Number:
  US11/992,643
• Publication Number:
  US 20090059564A1
• Time in Patent Office: Days
• US Class Current: 362/97.100
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 7/00 Mountings, adjusting means, or light-tight connections, for optical elements
• CPC Class Codes: G02F 1/133322 Mechanical guidance or alignment of LCD panel support components
• CPC Class Codes: G02F 1/133388 with constructional differences between the display region and the peripheral region
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means
• CPC Class Codes: G02F 2203/03 scattering

Abstract

The light diffusion plate 30 of the present invention has a rectangular shaped main body 31 including a part forming the effective surface of a backlight device 1 and a peripheral edge part 32 formed at an outer circumferential part of the main body 31 and forming a non-effective surface of the backlight device 1. The main body 31 has a diagonal length of 500 mm or more. The peripheral edge part 32 is formed with a rectangular shaped boundary line 30X for adjusting the position of the light diffusion plate 30 with respect to the housing 20. The housing 20 is formed with arrows 21X and 21Y for alignment with two sides A and B of one corner of the rectangular shaped boundary line 30X.

Claims

1. A light diffusion plate used in a backlight device provided with a linear light source, a housing holding said linear light source, and a light diffusion plate arranged at an emitting surface side of this housing and diffusing and emitting light from said linear light source,

said light diffusion plate having a rectangular shaped main body including a part forming an effective surface of said backlight device and a peripheral edge part formed at an outer circumferential part of the main body and forming a non-effective surface of said backlight device,

said main body having a diagonal length of 500 mm or more, and

said peripheral edge part formed with a positioning part for adjusting a position of said light diffusion plate with respect to said housing.

2. A light diffusion plate as set forth in claim 1, wherein

said light diffusion plate is formed using an injection molding mold having a core plate for forming said main body and a side frame arranged abutting against an outer circumferential end of said core plate and forming said peripheral edge, and

said positioning part is a rectangular shaped boundary line formed by a step difference at the abutting part of said core plate and said side frame.

3. A light diffusion plate as set forth in claim 2, wherein said step difference has a height of 1 μ

m or more.

4. A light diffusion plate as set forth in claim 1, wherein

said light diffusion plate is formed using an injection molding mold having a core plate for forming the main body and a side frame arranged abutting against an outer circumferential end of said core plate and forming said peripheral edge part, and

said positioning part is a rectangular shaped boundary line formed into a projecting shape by the clearance part between said core plate and said side frame.

5. A light diffusion plate as set forth in claim 4, wherein said projection forming the boundary line has a width of 1 μ

m or more.

6. A light diffusion plate as set forth in claim 4, wherein said projection forming the boundary line has a height of 1 μ

m or more.

7. A light diffusion plate as set forth in claim 2, wherein said housing is provided with marks for alignment with the two sides of a corner part of said boundary line formed in to a rectangular shape.

8. A light diffusion plate as set forth in claim 1, wherein said main body is formed with a prism array having a plurality of linear prisms extending substantially parallel to the longitudinal direction of said linear light source.

9. A light diffusion plate as set forth in claim 1, wherein said main body is formed with a patterned part having repeated recessed structures or projecting structures, each structure has three or more surfaces, and said recessed structures or projecting structures have a maximum height Rz of 1,000 μ

m or less.

10. A light diffusion plate as set forth in claim 9, wherein said recessed structures or projecting structures have pyramidal or truncated pyramidal shapes respectively.

11. A light diffusion plate as set forth in claim 9, wherein said patterned part has repeated projecting structures, and said projecting structures are formed by cutting into a prism array having a plurality of linear prisms along a direction perpendicularly intersecting the longitudinal direction of said linear prisms in V-cross-sectional shapes.

12. A light diffusion plate as set forth in claim 9, wherein said patterned part has repeated recessed structures, and said recessed structures are transferred using a member having projecting structures formed by cutting into a prism array having a plurality of linear prisms along a direction perpendicularly intersecting the longitudinal direction of said linear prisms in V-cross-sectional shapes.

13. A backlight device comprising said light diffusion plate as set forth in claim 1.