BACKLIGHT CONTROL UNIT

• US 20080150884A1
• Filed: 12/17/2007
• Published: 06/26/2008
• Est. Priority Date: 12/26/2006
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: ITO, Ken
• Application Number:
  US11/958,197
• Publication Number:
  US 20080150884A1
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G09G 2310/0232 Special driving of display border areas
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

According to one embodiment, a gain output of only light emitting elements positioning at a center portion of a light emitting element region of a light emitting portion is increased by a gain adjusting filter in a backlight control unit, and therefore, it becomes possible to decrease an output of the light emitting elements at the center portion of which drive time becomes long when a contrast of a liquid crystal is optimized. Accordingly, a variation of deterioration between the light emitting elements can be suppressed effectively even when the light emitting elements at the center portion of which drive time is long and the light emitting elements at circumferential edges of which drive time is short are mixed at the light emitting portion.

Claims

1. A backlight control unit in which plural light emitting elements are disposed at one surface side, a light emitting device irradiating light of the light emitting elements from a rear surface side of a liquid crystal is held, and an output of each light emitting element of the light emitting device is adjusted so that a contrast is optimized in accordance with a video display level of the liquid crystal,

wherein densities of the light emitting elements are different between circumferential edges and a center portion at a light emitting element region where the light emitting elements of the light emitting device are disposed.

2. The backlight control unit according to claim 1,

wherein the density of the light emitting elements at the center portion is higher than the density of the light emitting elements at the circumferential edges at the light emitting element region of the light emitting device.

3. The backlight control unit according to claim 1,

wherein an output of the light emitting elements of which density is high, is smaller than an output of the light emitting elements of which density is low, between the center portion and the circumferential edges of the light emitting element region.

4. A backlight control unit in which plural light emitting elements are disposed at one surface side, a light emitting device irradiating light of the light emitting element from a rear surface side of a liquid crystal is held, and an output of each light emitting element of the light emitting device is adjusted so that a contrast is optimized in accordance with a video display level of the liquid crystal,

wherein radiation directions of the light emitting elements at circumferential edges are inclined toward a center portion side of a light emitting element region at the light emitting element region where the light emitting elements of the light emitting device are disposed.

5. A backlight control unit in which plural light emitting elements are disposed at one surface side, a light emitting device irradiating light of the light emitting element from a rear surface side of a liquid crystal is held, and an output of each light emitting element of the light emitting device is adjusted so that a contrast is optimized in accordance with a video display level of the liquid crystal, comprising:

a gain adjusting filter disposed at a front surface of the light emitting device, and increasing a gain output of only the light emitting elements positioning at a center portion of a light emitting element region where the light emitting elements of the light emitting device are disposed,

wherein an output of the light emitting elements positioning at the center portion of the light emitting element region is smaller than an output of the light emitting elements positioning at circumferential edges of the light emitting element region.