Image display device and image display method

• US 20080100645A1
• Filed: 09/19/2007
• Published: 05/01/2008
• Est. Priority Date: 09/20/2006
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nitta, Takashi
• Granted Patent: US 8,674,926 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/148 the light being detected by light detection means within each pixel
• 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

An image display device includes: an optical modulation element having a plurality of pixels; light sources illuminating the optical modulation element, each of which is independently controlled; a light source control value setting section setting control values for each of the light sources according to the grayscale of each pixel of an input image; optical sensors provided on areas of “n” pixels, respectively, where the “n” is an integer equal to or greater than 1; an illumination detection section detecting the illumination of the areas by the optical sensors; and a grayscale control section processing to correct grayscale of each pixel based on the detected illumination and controlling the optical modulation element according to the corrected grayscales obtained by correction.

Claims

1. An image display device, comprising:

an optical modulation element having a plurality of pixels;

light sources illuminating the optical modulation element, each of which is independently controlled;

a light source control value setting section setting control values for each of the light sources according to the grayscale of each pixel of an input image;

optical sensors provided on areas of “

n”

pixels, respectively, where the “

n”

is an integer equal to or greater than 1;

an illumination detection section detecting the illumination of the areas by the optical sensors; and

a grayscale control section processing to correct grayscale of each pixel based on the detected illumination and controlling the optical modulation element according to the corrected grayscales obtained by correction.

2. The image display device according to claim 1, wherein

the optical sensors and the optical modulation element are formed on the identical substrate.

3. The image display device according to claim 1, wherein

the optical sensors are provided on the pixels, respectively.

4. The image display device according to claim 1, wherein

the optical sensors are provided on the areas of the pixels equal to or less than 40×

40.

5. The image display device according to claim 1, wherein

the grayscale control section performs black display control so as to display black in all pixels of the optical modulation element during a correction processing period to determine the corrected grayscales.

6. The image display device according to claim 5, wherein

the light source control value setting section turns all of the light sources off in synchronization with the black display control.

7. The image display device according to claim 1, wherein

the light source control value setting section sets control values for the light sources every “

k”

frames where the “

k”

is an integer equal to or greater than 2, the illumination detection section detects the illumination of the areas every “

k”

frames, and the grayscale control section controls the optical modulation element due to the corrected grayscales every a single-frame.

8. The image display device according to claim 1, further comprising:

a scene change detection section detecting whether an image data has been input in the period of “

k”

frames, the image data having grayscales which is impossible to display at the current illumination distribution of light source, wherein

the light source control value setting section sets the light sources to a full-screen dimming mode, which is substantially the same illumination corresponding to the maximum grayscale in the image data, when the scene change detection section detects the fact that the image data is impossible to display at the current illumination distribution, and wherein

the light source control value setting section sets an area dimming mode in which control values for each of the light sources are set according to grayscales of the pixels for the input image at the timing of the next illumination detection by the illumination detection section.

9. The image display device according to claim 8, wherein

the scene change detection section compares grayscales of all pixels of input image data with the range of grayscales which is possible to display at the current control values of each light source, and wherein

the scene change detection section determines whether the image data has been input, the image data being impossible to reproduce at the current illumination of light source due to whether the grayscales of all of the pixels are within the range.

10. The image display device according to claim 8, wherein

the scene change detection section, by detecting a scene change in the image data, determines whether the image data has been input, the image data being impossible to reproduce at the current light source illumination.

11. An image display method, comprising:

illuminating an optical modulation element having a plurality of pixels by light sources, each of the light sources being independently controlled;

setting control values for each of the light sources by a light source control value setting section according to the grayscale of each pixel of an input image;

detecting the illumination of areas by an illumination detection section and by optical sensors provided on areas of “

n”

pixels, respectively, where “

n”

is an integer equal to or greater than 1;

processing to correct the grayscale for each pixel by a grayscale control section, and controlling the optical modulation element according to the corrected grayscales obtained by correction, based on the detected illumination.