Liquid crystal display apparatus comprising a reflection sheet having a higher degree of freedom of movement in a direction along its surface

• US 8,339,540 B2
• Filed: 05/24/2011
• Issued: 12/25/2012
• Est. Priority Date: 05/27/2010
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Obata, Hiroshi, Fujimoto, Makoto
• Primary Examiner(s): Robinson, Mark
• Assistant Examiner(s): LEE, PAUL CHANG
• Application Number:
  US13/114,749
• Publication Number:
  US 20110292316A1
• Time in Patent Office: 581 Days
• Field of Search: 349 61- 64, 349/67, 349/69, 362 971- 974, 362/249.02, 362/311.02, 362/545, 362/555, 362/800
• US Class Current: 349/67
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means

Abstract

A reflection sheet is made of material having a coefficient of thermal expansion different from that of an LED substrate. A fixing member and a retaining member extend through the reflection sheet and the LED substrate so as to fix the reflection sheet and the LED substrate. The reflection sheet includes a fixing hole into which the fixing member is inserted, a retaining hole into which the retaining member is inserted, and LED holes within which light emitting diodes are disposed, respectively. Retaining of the reflection sheet by the retaining member has, compared to fixing of the reflection sheet by the fixing member, a higher degree of freedom of movement in a direction along a surface of the reflection sheet. The LED holes located in positions far from the fixing hole are larger than the LED holes located in positions close to the fixing hole.

Claims

1. A liquid crystal display apparatus, comprising:

a liquid crystal display panel;

a plurality of light emitting diodes serving as backlight light sources of the liquid crystal display panel;

an LED substrate on which the plurality of light emitting diodes are mounted;

a reflection sheet made of a material having a coefficient of thermal expansion different from a coefficient of thermal expansion of the LED substrate and overlaid on a surface of the LED substrate on which the plurality of light emitting diodes are mounted; and

a fixing member and a retaining member which extend through the reflection sheet and the LED substrate so as to fix the reflection sheet and the LED substrate to each other, wherein;

the reflection sheet comprises a fixing hole into which the fixing member is inserted, a retaining hole into which the retaining member is inserted, and a plurality of LED holes within which the plurality of light emitting diodes are disposed, respectively;

retaining of the reflection sheet by the retaining member has, compared to fixing of the reflection sheet by the fixing member, a higher degree of freedom of movement in a direction along a surface of the reflection sheet; and

the plurality of LED holes located in positions far from the fixing hole are larger than the plurality of LED holes located in positions close to the fixing hole.

2. The liquid crystal display apparatus according to claim 1, wherein the fixing hole is located in a position closer to a center of the reflection sheet compared to the retaining hole.

3. The liquid crystal display apparatus according to claim 2, wherein:

the fixing hole comprises a plurality of fixing holes, the plurality of fixing holes being formed in a central region of the reflection sheet; and

the retaining hole comprises a plurality of retaining holes, the plurality of retaining holes being formed in an end region of the reflection sheet.

4. The liquid crystal display apparatus according to claim 3, wherein:

the LED substrate is divided into a plurality of divided substrates;

each of the plurality of divided substrates includes a first through-hole brought into communication with the fixing hole and a second through-hole brought into communication with the retaining hole; and

the plurality of divided substrates are arranged so that the first through-holes are close to one another and the second through-holes are apart from one another.

5. The liquid crystal display apparatus according to claim 1, wherein a clearance between the fixing hole and the fixing member is smaller than a clearance between the retaining hole and the retaining member.

6. The liquid crystal display apparatus according to claim 4, wherein a clearance between the fixing hole and the fixing member is smaller than a clearance between the retaining hole and the retaining member.

7. The liquid crystal display apparatus according to claim 1, wherein:

the fixing member is fitted so as to clamp the reflection sheet and the LED substrate; and

the retaining member is fitted so as not to apply any pressing force between the reflection sheet and the LED substrate.

8. The liquid crystal display apparatus according to claim 6, wherein:

the fixing member is fitted so as to clamp the reflection sheet and the LED substrate; and

the retaining member is fitted so as not to apply any pressing force between the reflection sheet and the LED substrate.

9. The liquid crystal display apparatus according to claim 1, wherein the retaining hole is elongated in a direction of thermal expansion of the reflection sheet.

10. The liquid crystal display apparatus according to claim 8, wherein the retaining hole is elongated in a direction of thermal expansion of the reflection sheet.

11. The liquid crystal display apparatus according to claim 1, wherein at least one of the plurality of LED holes is elongated in a direction of thermal expansion of the reflection sheet.

12. The liquid crystal display apparatus according to claim 10, wherein at least one of the plurality of LED holes is elongated in the direction of thermal expansion of the reflection sheet.