Illuminator, projection display device, and method for driving the same

• US 8,674,903 B2
• Filed: 02/01/2010
• Issued: 03/18/2014
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yoshida, Shohei
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Shapiro, Leonid
• Application Number:
  US12/697,665
• Publication Number:
  US 20100149495A1
• Time in Patent Office: 1,506 Days
• Field of Search: 345/32, 345/31, 345/87, 345/102, 345/204
• US Class Current: 345/32
• 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 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406

Abstract

The invention provides a projection display device capable of appropriate light control depending on the kind of the image, the ambient brightness and so on, a method for driving the same, and an illuminator used in the same. The light flux of illumination can be adjusted on the basis of image information. The allowable light control range (dimming control) can be optimally set depending on the information (usage information) on the kind of viewed content, the brightness of viewing environment, the gain of a screen and the like.

Claims

1. A projection display device comprising:

a light source;

a photosensor configured to measure brightness of a viewing environment;

a light flux setting device configured to set a light flux emitted by the light source on the basis of image information;

a dimming-range setting device configured to set a dynamic dimming range in which dimming is allowed, such that the brighter a brightness of a viewing environment measured by the photosensor is, the narrower the dimming-range setting device sets the dynamic dimming range;

a light control device configured to adjust the light flux emitted by the light source on the basis of the light flux emitted by the light source set by the light flux setting device and the dynamic dimming range set by the dimming-range setting device;

a light modulation device configured to modulate light adjusted by the light control device; and

a projection device configured to project the light modulated by the light modulation device.

2. The projection display device according to claim 1, wherein the dimming-range setting device sets the dynamic dimming range on the basis of a control table that specifies a relationship between the brightness of the viewing environment measured by the photosensor and a maximum allowable dimming amount.

3. The projection display device according to claim 1, further comprising an image-signal expanding device that is configured to expand an image signal on the basis of a dimming amount of the light source.

4. A method for controlling the projection display device according to claim 1, comprising:

setting the dynamic dimming range, which is narrowed the brighter the brightness of viewing environment measured by the photosensor is;

adjusting the light flux emitted by the light source within the dynamic dimming range set by the dimming-rage setting device on the basis of image signals in unit time; and

expanding the image signals on the basis of the dimming amount of the light source; and

transmitting the expanded image signals to the light modulation device to form an image.

5. The projection display device according to claim 3, wherein the image-signal expanding device is configured to:

i) expand the image signal by a first expansion coefficient that is a reciprocal of an amount of the light flux, when a dimming amount of the amount of the light flux is within the dynamic dimming range, and ii) expand the image signal by a second expansion coefficient that is larger than the first expansion coefficient, when a dimming amount of the amount of the light flux is outside of the dynamic dimming range.