Display device, instrument panel, automatic vehicle, and method of driving display device

• US 7,956,838 B2
• Filed: 01/20/2006
• Issued: 06/07/2011
• Est. Priority Date: 01/25/2005
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Mizumaki, Hidetaka
• Primary Examiner(s): Liang; Regina
• Assistant Examiner(s): Sheng; Tom V
• Application Number:
  US11/814,386
• Publication Number:
  US 20090033611A1
• Time in Patent Office: 1,964 Days
• Field of Search: 345/102, 362600-616
• US Class Current: 345/102
• CPC Class Codes: B60K 2360/33 Illumination features
• CPC Class Codes: B60K 2370/33 Illumination features
• CPC Class Codes: B60K 35/00 Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• 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

A display device includes an illuminator; a display panel for performing displaying by using light which is emitted from the illuminator; and a control circuit for controlling the illuminator. The illuminator includes a plurality of light source blocks, at least one light source belonging to each of the plurality of light source blocks. A displaying region of the display panel has a plurality of regions each performing displaying by using light which is emitted from a respective one of the light source blocks. The control circuit detects a level of a display signal which is input to each of the plurality of regions, and is capable of controlling a luminance of the respective light source block in accordance with the detected level of the display signal.

Claims

1. A display device comprising:

an illuminator;

a display panel for performing displaying by using light which is emitted from the illuminator; and

a control circuit for controlling the illuminator;

wherein

the illuminator includes a plurality of light source blocks, at least one light source belonging to each of the plurality of light source blocks;

a displaying region of the display panel has a plurality of regions each performing displaying by using light which is emitted from a respective one of the plurality of light source blocks;

the control circuit detects a level of a display signal which is input to each of the plurality of regions, and is capable of controlling a luminance of the respective light source block in accordance with the detected level of the display signal; and

each of the plurality of light source blocks includes, near a boundary with an adjoining light source block, a further light source which is controlled in a similar manner to the light source belonging to the adjoining light source block.

2. The display device of claim 1, wherein, in accordance with the level of a display signal corresponding to a highest display luminance among display signals having been detected with respect to each of the plurality of regions, the control circuit controls the luminance of each light source block based on a predetermined relationship which assigns a higher luminance for the light source block as a display luminance corresponding to the display signal becomes higher.

3. The display device of claim 1, wherein the control circuit controls the luminance of each light source block by varying an emission intensity of the light source belonging to each light source block.

4. The display device of claim 1, wherein the control circuit is capable of controlling the luminance of each light source block by varying an activation time of the light source belonging to the respective light source block.

5. The display device of claim 1, wherein the plurality of regions include at least two regions arranged along a horizontal scanning direction of the display panel.

6. The display device of claim 5, wherein, during a plurality of periods into which a specific horizontal scanning period is divided, the control circuit sequentially detects levels of display signals which are input to the at least two regions arranged along the horizontal scanning direction.

7. The display device of claim 1, wherein the plurality of regions include at least two regions arranged along a vertical scanning direction of the display panel.

8. The display device of claim 7, wherein, during a plurality of periods into which a specific vertical scanning period is divided, the control circuit sequentially detects levels of display signals which are input to the at least two regions arranged along the vertical scanning direction.

9. The display device of claim 1, wherein the control circuit varies the luminance of each light source block once in a plurality of vertical scanning periods.

10. The display device of claim 9, wherein the illuminator includes a power supply which is provided in common for the plurality of light source blocks.

11. The display device of claim 10, wherein the power supply outputs a constant level of current.

12. The display device of claim 10, wherein the power supply has a limiter.

13. The display device of claim 1, wherein the illuminator is an edge-light type illuminator.

14. The display device of claim 1, wherein the illuminator is a direct-type illuminator.

15. The display device of claim 1, wherein the display panel includes a pair of opposing substrates and a liquid crystal layer provided between the pair of substrates.

16. The display device of claim 1, wherein the display device is a display device to be mounted in an automotive vehicle.

17. An instrument panel comprising the display device of claim 1.

18. The instrument panel of claim 17, wherein the illuminator is configured so that, in the displaying region of the display panel, light is substantially not emitted in any portion not being used as a displaying region of the instrument panel.

19. An automotive vehicle comprising the instrument panel of claim 17.

20. A driving method for a display device having an illuminator and a display panel for performing displaying by using light which is emitted from the illuminator, wherein the illuminator includes a plurality of light source blocks, at least one light source belonging to each of the plurality of light source blocks, and a displaying region of the display panel has a plurality of regions each performing displaying by using light which is emitted from a respective one of the plurality of light source blocks, the driving method comprising:

a step of detecting a level of a display signal which is input to each of the plurality of regions; and

a step of controlling a luminance of the respective light source block in accordance with the detected level of the display signal;

wherein

each of the plurality of light source blocks includes, near a boundary with an adjoining light source block, a further light source which is controlled in a similar manner to the light source belonging to the adjoining light source block.

21. The driving method for a display device of claim 20, wherein the step of controlling the luminance of each light source block is performed, in accordance with the level of a display signal corresponding to a highest display luminance among display signals having been detected with respect to each of the plurality of regions, so as to assign a higher luminance for the light source block as a display luminance corresponding to the display signal becomes higher.

22. The driving method for a display device of claim 20, wherein the step of controlling the luminance of each light source block is performed by varying an emission intensity of the light source belonging to each light source block.

23. The driving method for a display device of claim 20, wherein the step of controlling the luminance of each light source block is performed by varying an activation time of the light source belonging to the respective light source block.