IMAGE DISPLAY DEVICE, CONTROL DEVICE FOR SAME, AND INTEGRATED CIRCUIT

• US 20120105509A1
• Filed: 06/30/2010
• Published: 05/03/2012
• Est. Priority Date: 07/01/2009
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ito, Takeshi, Yamashita, Haruo
• Application Number:
  US13/381,625
• Publication Number:
  US 20120105509A1
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Disclosed is an image display device having improved image qualities, while reducing power consumption. A backlight unit (20) includes a plurality of light sources disposed so as to form a plurality of light emission regions. A liquid crystal panel (10) displays an image by modulating light emitted from the backlight unit (20) in accordance with light emission transmissivity. A control unit (40) controls the light emission luminance value of the backlight unit (20) for each light emission region, and controls a liquid crystal display device (1). The control unit (40) calculates the light emission transmissivity, on the basis of the distances between the pixels of the liquid crystal panel (10) and the reference position(s) in one or more light emission regions, the luminance value of light that arrives the pixels, said luminance value being determined on the basis of the controlled light emission luminance value, and the image signals inputted to the pixels.

Claims

1. An image display apparatus comprising:

a light source section including a plurality of light sources arranged so that a plurality of light emission areas are formed;

a display section that displays an image by modulating light from the light source section in accordance with a modulation coefficient corresponding to an input image signal;

a light source control section that controls a light emission luminance value of the light source section for each light emission area; and

a control section that controls the image display apparatus.

wherein the control section. based on distance information indicating a distance between a pixel of the display section and a reference position in each of one or more light emission areas, a luminance value of light arriving at the pixel decided based on a controlled light emission luminance value, and an input image signal of the pixel, calculates the modulation coefficient corresponding to an input image signal of the pixel.

2. The image display apparatus according to claim 1, wherein the control section uses a linear distance between two-dimensional coordinates of the pixel on a predetermined surface and two-dimensional coordinates of the reference position as a value of the distance information.

3. The image display apparatus according to claim 1, wherein:

the light source control section generates a luminance signal indicating a light emission luminance value of the light source section for each light emission area; and

the control section acquires a normalized luminance value of the pixel based on the distance information, and decides a luminance value of light arriving at the pixel by correcting an acquired normalized luminance value based on the generated luminance signal.

4. The image display apparatus according to claim 3, wherein:

the control section uses a function that derives a normalized luminance value from distance information indicating a distance between the pixel and a reference position in a specific light emission area to acquire a normalized luminance value of the specific light emission area; and

the function is set for each light emission area.

5. The image display apparatus according to claim 1, wherein the control section decides a luminance value of light arriving at the pixel while performing adjustment according to the fact that spreading of light from the reference position is nonuniform.

6. The image display apparatus according to claim 3, wherein:

the distance information includes horizontal distance information and vertical distance information; and

the control section acquires the normalized luminance value of the pixel based on the distance information by combining a collection of normalized luminance values of each light emission area based on the horizontal distance information and a collection of normalized luminance values of each light emission area based on the vertical distance information.

7. The image display apparatus according to claim 6, wherein:

the control section uses a function that derives a normalized luminance value from distance information indicating a distance between the pixel and a reference position in a specific light emission area to acquire a normalized luminance value of the specific light emission area; and

the function is set for each light emission area and for each of a horizontal direction and a vertical direction.

8. The image display apparatus according to claim 1,

wherein the control section corrects the distance information based on an angle of a line connecting the pixel and the reference position in order to be used in deciding a luminance value of light arriving at the pixel.

9. The image display apparatus according to claim 8,

wherein the control section, when an angle of a line connecting the pixel and a specific reference position corresponds to a direction in which spreading of light from the specific reference position is relatively greater, makes distance information indicating a distance between the pixel and the specific reference position relatively shorter.

10. The image display apparatus according to claim 1,

wherein the control section makes the distance information an identical value for all pixels positioned on a line of equal luminance set based on spreading of light from a specific reference position.

11. The image display apparatus according to claim 10,

wherein a general form of the line of equal luminance is elliptical at a position near the specific reference position, and is circular at a position far from the specific reference position.

12. The image display apparatus according to claim 10,

wherein a general form of the line of equal luminance approaches circular from elliptical as distance increases from the specific reference position.

13. A control apparatus that performs control of an image display apparatus that displays an image by modulating, in accordance with a modulation coefficient corresponding to an input image signal, light from a light source section that includes a plurality of light sources arranged so that a plurality of light emission areas are formed and for which a light emission luminance value is controlled for each light emission area, the control apparatus comprising a control section that, based on distance information indicating a distance between a pixel and a reference position in each of one or more light emission areas, a luminance value of light arriving at the pixel decided based on a controlled light emission luminance value, and an input image signal of the pixel, calculates the modulation coefficient corresponding to an input image signal of the pixel.

14. An integrated circuit that performs control of a liquid crystal display apparatus, wherein:

the liquid crystal display apparatus has;

a light source section including a plurality of light sources arranged so that a plurality of light emission areas are formed; and

a display section that displays an image by modulating light from the light source section in accordance with a modulation coefficient corresponding to an input image signal;

the integrated circuit has;

a light source control section that controls a light emission luminance value of the light source section for each light emission area; and

a control section that controls the display apparatus; and

the control section, based on distance information indicating a distance between a pixel of the display section and a reference position in each of one or more light emission areas, a luminance value of light arriving at the pixel decided based on a controlled light emission luminance value, and an input image signal of the pixel, calculates the modulation coefficient corresponding to an input image signal of the pixel.