LIGHT EMISSION CONTROLLER AND LIQUID CRYSTAL DISPLAY APPARATUS INCLUDING LIGHT EMISSION CONTROLLER

• US 20090167655A1
• Filed: 12/17/2008
• Published: 07/02/2009
• Est. Priority Date: 12/26/2007
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ito, Ken, Tsuchida, Masaki
• Application Number:
  US12/337,474
• Publication Number:
  US 20090167655A1
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

According to one embodiment, a light emission controller has a light-value-change detector and a lighting controller. The lighting-value-change detector is configured to detect a change in a lighting value of a plurality of light sources. The lighting controller is configured to turn on the plurality of light sources at a plurality of lighting timings within a lighting period defined between an initial lighting timing and a final lighting timing of the plurality of lighting timings by pulse width modulation in accordance with the change in the lighting value, a number of the lighting timings in a later lighting period of the lighting period being greater than a number of the lighting timings in an earlier lighting period of the lighting period.

Claims

1. A light emission controller for controlling light emissions of a plurality of light sources included in a light emitter illuminating a liquid crystal panel by the plurality of light sources each of which is provided with respect to each of a plurality of light source areas, the light emission controller comprising:

a lighting-value-change detector configured to detect a change in a lighting value of the plurality of light sources; and

a lighting controller configured to turn on the plurality of light sources at a plurality of lighting timings within a lighting period defined between an initial lighting timing and a final lighting timing of the plurality of lighting timings by pulse width modulation in accordance with the change in the lighting value, a number of the lighting timings in a later lighting period of the lighting period being greater than a number of the lighting timings in an earlier lighting period of the lighting period.

2. The light emission controller according to claim 1, wherein

the lighting controller delays at least one of the lighting timings, and turns on the plurality of light sources at the lighting timings so that the plurality of light sources are turned on within the later lighting period.

3. The light emission controller according to claim 2, wherein

the lighting controller controls the lighting timings so that the lighting timings converges to the final lighting timing, and turns on the plurality of light sources at the lighting timings.

4. The light emission controller according to claim 1, further comprising:

a determination module configured to determine whether the change in the lighting value is greater than a predetermined reference value, wherein

the lighting-value-change detector outputs a detection signal when the determination module determines that the change in the lighting value is greater than the reference value, and

the lighting controller turns on the plurality of light sources at the lighting timings when the detected signal is output.

5. The light emission controller according to claim 4, wherein

the lighting controller uniformly distributes the lighting timings within the lighting period, and turns on the plurality of light sources when the detected signal is not output.

6. The light emission controller according to claim 1, further comprising:

a lighting value determination module configured to determine the lighting value of the plurality of light sources based on an input video signal, wherein

the lighting-value-change detector detects the change in the lighting value of the plurality of light sources based on the lighting value determined by the lighting value determination module.

7. A liquid crystal display apparatus comprising:

a liquid crystal panel;

a light emitter configured to illuminate the liquid crystal panel by a plurality of light sources each of which is provided with respect to each of a plurality of light source areas;

a light emission controller configured to control a light emission of the plurality of light sources;

a lighting-value-change detector configured to detect a change in a lighting value of the plurality of light sources; and

a lighting controller configured to turn on the plurality of light sources at a plurality of lighting timings within a lighting period defined between an initial lighting timing and a final lighting timing of the plurality of lighting timings by pulse width modulation in accordance with the change in the lighting value, a number of the lighting timings in a later lighting period of the lighting period being greater than a number of the lighting timings in an earlier lighting period of the lighting period

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

the lighting controller delays at least one of the lighting timings, and turns on the plurality of light sources at the lighting timings so that the plurality of light sources are turned on within the later lighting period.

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

the lighting controller controls the lighting timings so that the lighting timings converges to the final lighting timing, and turns on the plurality of light sources at the lighting timings