Display device and projection display device

• US 20050007306A1
• Filed: 05/24/2004
• Published: 01/13/2005
• Est. Priority Date: 05/29/2003
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yoshida, Shohei, Ilsaka, Hidehito, Takeda, Takashi, Sakata, Hidefumi
• Application Number:
  US10/851,218
• Publication Number:
  US 20050007306A1
• Time in Patent Office: Days
• US Class Current: 345/32
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3182 Colour adjustment, e.g. white balance, shading or gamut white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607

Abstract

The invention provides a display device, a direct-view display device, and a projection display device in which their apparent dynamic ranges are increased with less color change. The display device can include a light modulation device having a plurality of pixels for displaying an image according to an image signal, a light source for illuminating the light modulation device, and a light-source driving device for controlling the intensity of light emitted from the light source by controlling the period in which the light source is lit at a specified brightness per unit time.

Claims

1. A display device, including a light modulation device having a plurality of pixels that display an image according to an image signal, comprising:

a light source that illuminates the light modulation device; and

a light-source driving device that controls an intensity of light by controlling a period in which the light source is lit at a specified brightness per unit time.

2. The display device according to claim 1,

the light-source driving device including a brightness extraction device that extracts a parameter characterizing a brightness of an image from the image signal;

and

the light-source driving device controlling the intensity of light on a basis of the parameter extracted by the brightness extraction device.

3. The display device according to claim 2, the display device being controlled so that the image signal displayed by the light modulation device is subjected to image processing on the basis of the parameter characterizing the brightness of the image.

4. The display device according to claim 1,

the light-source driving device controlling a number of lightings of the light source to one per unit time and controlling the lighting period for each one time to thereby control the intensity of light emitted from the light source per unit time.

5. The display device according to claim 1,

the light-source driving device controlling a number of lightings of the light source to a specified number of two or more per unit time and controlling the lighting period for each one to thereby control the intensity of light emitted from the light source per unit time.

6. The display device according to claim 1,

the light-source driving device fixing the lighting period of the light source to a specified lighting period and controlling a number of lightings per unit time to thereby control the intensity of light emitted from the light source per unit time.

7. The display device according to claim 1, the light-source driving device controlling the light source to be lit all the time when a parameter characterizing the brightness of the image is at a maximum.

8. The display device according to claim 1, the light-source driving device controlling the light source to be lit intermittently when a parameter characterizing the brightness of the image is at a maximum.

9. The display device according to claim 1, the light-source driving device controlling the lighting period in which the light source is lit at a specified brightness per unit time and controlling the light source to light at a brightness lower than the specified brightness during a time other than the lighting time.

10. A projection display device, comprising a projection device that projects the light modulated by the light modulation device, in addition to the display device according to claim 1.

11. The projection display device according to claim 10,

the projection display device including three light modulation elements corresponding to the three primary colors, and three light sources capable of emitting the respective color lights;

and

the light-source driving device shifting lighting timing of the light-source for each of the different color lights.

12. The projection display device according to claim 10,

the projection display device including three light modulation elements corresponding to the three primary colors, and three light sources capable of emitting the respective color lights;

and

the light-source driving device coinciding all lighting timing of the light-source with one another.

13. The projection display device according to claim 10, the light source including light-emitting diodes capable of emitting different color lights.