Area light source apparatus

• US 7,033,064 B2
• Filed: 01/12/2004
• Issued: 04/25/2006
• Est. Priority Date: 01/14/2003
• Status: Expired due to Fees

• Current Assignee: Japan Display Central Incorporated (Japan Display Incorporated)
• Original Assignee: Toshiba Matsushita Display Technology Co Ltd (Japan Display Incorporated)
• Inventors: Ida, Kazushige
• Primary Examiner(s): Cariaso, Alan
• Assistant Examiner(s): Rehm, Adam C.
• Application Number:
  US10/754,719
• Publication Number:
  US 20040141309A1
• Time in Patent Office: 834 Days
• Field of Search: 362600-634
• US Class Current: 362/634
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0088 of the light guide or other optical sheets in the package

Abstract

Cold cathode tube 22 is covered with lamp reflector 31. An edge portion on the side of incident light surface 26a of light guide 26 is interposed between upper and lower edge portions 31a and 31b of lamp reflector 31. Reflection sheet 29 is attached to the back surface 26b of light guide 26. Reflection sheet 29 is fixed on the front surface of frame 32 by adhesive tapes 41 for electric insulation. An interposing width of “A” where the edge portion on the side of incident light surface 26a of light guide 26 is interposed between upper and lower edge portions 31a and 31b of lamp reflector 31, which is larger than a gap of “B” defined between step portion 35 of frame 32 and edge 26d of light guide 26. With the structure arranged above, the edge portion on the side of incident light surface 26a of light guide 26 is firmly held between upper and lower edge portions 31a and 31b of lamp reflector 31.

Claims

1. An area light source apparatus comprising:

a light source;

a substantially rectangular area light conversion member to convert light from said light source into area light projected to a front surface of said area light conversion member, one side of said area light conversion member having an incident light surface and being provided adjacent to said light source;

a reflector covering said light source to reflect and project the light from said light source to said one side of said area light conversion member, the reflector including an upper edge portion and a lower edge portion, the upper and lower edge portions of said reflector being provided to interpose said one side of said area light conversion member;

a frame faced to support the other side of said area light conversion member opposite to said one side of said area light conversion member through a gap; and

suppression means provided between said area light conversion member and said frame and adjacent to said other side of said area light conversion member for suppressing said area light conversion member to shift toward said light source and front surface of said area light conversion member,

wherein a width formed by a front edge of the upper edge portion and the incident light surface of said one side of said area light conversion member interposed between said upper and lower edge portions of said reflector, is larger than said gap defined between said frame and said other side of said area light conversion member.

2. An area light source apparatus according to claim 1, wherein said suppressing means is an adhesive tape.

3. An area light source apparatus according to claim 1, further comprising optical sheet provided on an opposite surface to said front surface, wherein said optical sheet together with said area light conversion member is interposed between said upper and lower edge portions of said reflector.

4. An area light source apparatus according to claim 3, wherein said area light conversion member is attached to said frame through said optical sheet.

5. An area light source apparatus according to claim 1, wherein said width of said one side of said area light conversion member interposed between said upper and lower edge portions of said reflector is larger than said gap defined between said frame and said other side of said area light conversion member plus a shrink quantity caused by environmental temperature change from 25°

C. to −

20°

C.

6. An area light source apparatus according to claim 1, wherein said area light conversion member includes a prism provided on a side of a rear surface opposite to said front surface.

7. An area light source apparatus according to claim 1, wherein said suppressing means changes adhesiveness thereof depending on environmental temperatures.

8. An area light source apparatus according to claim 1, further comprising:

a holder to support both upper and lower edge portions of said light source, wherein said one side of said area light conversion member is disposed to contact with said holder.