Backlight assembly for liquid crystal display apparatus having inclined light emmitting elements

• US 7,967,462 B2
• Filed: 01/29/2009
• Issued: 06/28/2011
• Est. Priority Date: 02/12/2008
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ogiro, Kenji, Masuoka, Nobuo, Fujita, Kouji
• Primary Examiner(s): Negron; Ismael
• Application Number:
  US12/361,849
• Publication Number:
  US 20090201668A1
• Time in Patent Office: 880 Days
• Field of Search: 362 971- 974, 362/561, 362600-634, 362 26- 27, 362/330, 362/339, 362/231, 362/555, 385/146, 349 60- 64, 359/831, 359/837
• US Class Current: 362/97.2
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

A light source includes a plurality of light emitting elements, and each light emitting element is disposed in such a manner that a direction of an optical axis of the light emitting element having a highest luminance is disposed at a predetermined inclination angle relative to a plane of the liquid crystal display. The optical guide member has an optical guide portion of a wedge shape having a first flat plane generally perpendicular to the optical axis of each light emitting element for receiving light from each light emitting element and a second flat plane having a predetermined angle relative to the optical axis and intersecting the first flat plane at an acute angle for reflecting light. A plurality of optical guide portions are disposed in a plane and formed integrally along a predetermined direction corresponding to the inclination direction of the light emitting elements.

Claims

1. A liquid crystal display apparatus comprising:

a liquid crystal display;

a light source disposed on a back side of said liquid crystal display; and

an optical guide member for irradiating light from said light source to said liquid crystal display, wherein;

said light source includes a substrate and a plurality of light emitting elements mounted on said substrate, and each light emitting element is disposed in such a manner that a direction of an optical axis of said light emitting element having a highest luminance is disposed at a predetermined inclination angle relative to a plane of said liquid crystal display;

said optical guide member has an optical guide portion having a wedge shape on a plane facing each light emitting element, and said optical guide portion has a first flat plane generally perpendicular to said optical axis of each light emitting element for receiving light from each light emitting element and a second flat plane having a predetermined angle relative to said optical axis and intersecting said first flat plane for reflecting light;

a ridge line formed by said first flat plane and said second flat plane is positioned closer to the substrate than a plane including portions of said plurality of light emitting elements furthest from the substrate;

both high angle radiation light and low angle radiation light emitted from each light emitting element are incident on said first flat plane facing said light emitting element; and

a plurality of said optical guide portions are disposed in a plane and formed integrally along a predetermined direction corresponding to the inclination direction of said light emitting elements.

2. The liquid crystal display apparatus according to claim 1, wherein said optical guide member has a fine concave/convex pattern formed on a plane on an output plane side facing said liquid crystal display, and said fine concave/convex pattern diffuses light from said light source incident upon said optical guide member and outputs diffused light to said liquid crystal display.