Display device and method

• US 20060238487A1
• Filed: 03/29/2006
• Published: 10/26/2006
• Est. Priority Date: 03/29/2005
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: InnoLux Corporation
• Inventors: Shih, Ming-Chia
• Granted Patent: US 7,786,973 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines

Abstract

A region-based image display device includes a backlight module, a separating unit, a signal-processing unit, and a modulation unit. The backlight module includes several backlight regions. Each backlight region includes an adjustable luminance unit. Each luminance unit has a basis luminance value. The separating unit separates an input image signal into several image region signals corresponding to the backlight regions. The signal-processing unit transforms the image region signals into several output image signals. The modulation unit adjusts the basis luminance values to output luminance values according to the image region signals. Each basis luminance value and the corresponding image region signal on the one hand, and the corresponding output luminance value and output image signal, on the other hand, cooperatively define substantially the same chromaticity and brightness.

Claims

1. An image display device, comprising:

a backlight module having a plurality of backlight regions, each of the backlight regions comprising an adjustable luminance unit, each of the luminance units having a basis luminance value;

a separating unit for separating an input image signal into a plurality of image region signals, each of the image region signals corresponding to one of the backlight regions;

a signal-processing unit for receiving the image region signals and transforming the image region signals into a plurality of output image signals, respectively; and

a modulation unit for adjusting the basis luminance values to a plurality of output luminance values, respectively, according to the image region signals, respectively;

wherein each of the basis luminance values and the corresponding image region signal cooperatively define a chromaticity and brightness, and the corresponding output luminance value and the corresponding output image signal cooperatively define substantially the same chromaticity and brightness.

2. The image display device according to claim 1, having a gamma curve value (γ

) and a gamma curve, for expressing a relation between a luminance value (B) and a gray scale value (G) of the display, the relation being B=Gamma_γ

(G).

3. The image display device according to claim 1, wherein the signal-processing unit transforms each of the image region signals into the corresponding output image signal through linear magnification according to a maximum gray scale value of said image region signal.

4. The image display according to claim 3, wherein the modulation unit adjusts each of the basis luminance values to the corresponding output luminance value according to the maximum gray scale values of said image region signals.

5. The image display according to claim 4, having a gamma curve value (γ

) and a gamma curve, for expressing a relation between a luminance value (B) and a gray scale value (G) of the display, the relation being B=Gamma_γ

(G);

wherein, for an i^th backlight region, the output luminance value B_2i is represented by B_2i=100%×

Gamma_γ

(M_i), and the output image signal G_2i is represented by

$G_{2<br><br>i}=G_{1<br><br>i}\times <br><br>\frac{255}{M_i},$

where G_1i is the image region signal corresponding to said i^th backlight region, and M_i is the maximum gray scale value of said image region signal G_1i.

6. The image display according to claim 2, further comprising a low pass filter for outputting, based on said output luminance values, a plurality of adjusted luminance values, respectively, for the corresponding luminance units.

7. The image display according to claim 6, wherein each of the adjusted luminance values is determined through superposition of the corresponding output luminance value.

8. The image display according claim 1, further comprising a plurality of light shields disposed between the adjacent backlight regions, for preventing light of one backlight region from entering the others.

9. The image display according to claim 1, wherein the backlight module is a cold cathode fluorescent lamp (CCFL) backlight module or a light emitting diode (LED) backlight module.

10. The image display according to claim 2, wherein the gamma curve value (γ

) is 2.2.

11. An image displaying method for use in a region-based display device, the method comprising:

providing a backlight module in the display device, wherein the backlight module has a plurality of backlight regions, each of the backlight regions comprising an adjustable luminance unit, each of the luminance units having a basis luminance value;

separating an input region signal into a plurality of image region signals, each of the image region signals corresponding to one of the backlight regions, wherein each of the basis luminance values and the corresponding image region signal cooperatively define a chromaticity and brightness;

transforming the image region signals into a plurality of output image signals, respectively; and

according to the image region signals, adjusting the basis luminance values to a plurality of output luminance values, respectively, wherein each of the output luminance values and the corresponding output image signal cooperatively define substantially the same chromaticity and brightness as the corresponding basis luminance value and image region signal.

12. The method according to claim 11, wherein the display device has a gamma curve value (γ

) and a gamma curve, for expressing a relation between a luminance value (B) and a gray scale value (G) of the display device, the relation being B=Gamma_γ

(G)

13. The method according to claim 12, wherein in the transforming step, each said image region signal is transformed into the corresponding output image signal through linear magnification according to a maximum gray scale value of said image region signal.

14. The method according to claim 13, wherein in the adjusting step, each of the basis luminance values are adjusted to the corresponding output luminance value according to the maximum gray scale values of said image region signals.

15. The method according to claim 14, wherein the display has a gamma curve value (γ

) and a gamma curve, for expressing a relation between a luminance value (B) and a gray scale value (G) of the display, the relation being B=Gamma_γ

(G);

wherein, for an i^th backlight region,

the output luminance value B_2i is represented by

B_2i=100%×

Gamma_γ

(M_i), and the output image signal G_2i is represented by

$G_{2<br><br>i}=G_{1<br><br>i}\times <br><br>\frac{255}{M_i},$

where G_1i is the image region signal corresponding to said i^th backlight region, and M_i is the maximum gray scale value of said image region signal G_1i.

16. The method according to claim 12, wherein the adjusting step further comprises:

outputting a plurality of adjusted luminance values according to the output luminance values, respectively; and

using the adjusted luminance values in said luminance units.

17. The method according to claim 16, wherein each of the adjusted luminance values is determined through superposition of the corresponding output luminance value.

18. The method according to claim 11 further comprising disposing a plurality of light shields between the adjacent backlight regions, for preventing light of one backlight region from entering the others.

19. The method according to claim 11, wherein the backlight module is a cold cathode fluorescent lamp (CCFL) backlight module or a light emitting diode (LED) backlight module.

20. The method according to claim 12, wherein the gamma value (γ

) is 2.2.