DISPLAY DEVICE, DISPLAY DRIVER AND IMAGE DISPLAY METHOD

• US 20130044146A1
• Filed: 10/09/2012
• Published: 02/21/2013
• Est. Priority Date: 04/24/2007
• Status: Abandoned Application

• Current Assignee: Akihisa Aoyama, Akihito Akai, Goki Toshima, Goro Sakamaki, Hiroki Awakura, Naoki Takada, Yasuyuki Kudo, Yoshiki Kurokawa, Yukari Katayama
• Original Assignee: Akihisa Aoyama, Akihito Akai, Goki Toshima, Goro Sakamaki, Hiroki Awakura, Naoki Takada, Yasuyuki Kudo, Yoshiki Kurokawa, Yukari Katayama
• Inventors: KUROKAWA, Yoshiki, KATAYAMA, Yukari, AWAKURA, Hiroki, TAKADA, Naoki, KUDO, Yasuyuki, AKAI, Akihito, TOSHIMA, Goki, SAKAMAKI, Goro, AOYAMA, Akihisa
• Application Number:
  US13/647,710
• Publication Number:
  US 20130044146A1
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/064 by time 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 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• 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: G09G 3/3611 Control of matrices with row and column drivers

Abstract

In a display device and a display driver, when a grayscale of a display image is equal to or lower than a specific grayscale value obtained from a histogram of the display image, a display grayscale is extended with a linear function. On the other hand, when a grayscale of a display image is equal to or higher than the specific grayscale value, histogram equalization of a part higher than the specific grayscale value is performed, and the display grayscale is extended with a non-linear function obtained from the histogram equalization.

Claims

1. A drive circuit of an image display device for displaying an image by irradiating a backlight on a display screen, the drive circuit comprising:

a backlight control unit which includes;

a histogram counting unit for acquiring a histogram by counting display data in units of frame of one or plural images and calculating a value of the display data at a specific upper position of the histogram;

a display data extension unit for extending each display data based on the value of the display data at the specific position; and

a backlight adjustment unit for adjusting a light emission amount of the backlight based on the value of the display data at the specific position,

wherein the histogram counting unit includes a weighting coefficient calculating unit for outputting a weighting coefficient corresponding to a display position of each display data on the display screen, and counts the display data while adding the weighting coefficient to each display data, thereby acquiring the histogram.

2. The drive circuit of the image display device according to claim 1,

wherein the weighting coefficient calculating unit selects and outputs a weighting coefficient corresponding to a display region, to which the display position of each display data on the display screen belongs, based on a weighting coefficient defined for each of plural display regions on the display screen.

3. The drive circuit of the image display device according to claim 2, further comprising:

a register for storing the weighting coefficient defined for each of plural display regions on the display screen,

wherein the weighting coefficient can be externally changed.

4. The drive circuit of the image display device according to claim 2, further comprising:

a register for storing information for specifying plural display regions on the display screen,

wherein the information can be externally changed.

5. The drive circuit of the image display device according to claim 2,

wherein the image display device is an image display device of an information equipment, and

at least one of the plural display regions of the display screen corresponds to a region on which an icon displayed by the information equipment is displayed.

6. The drive circuit of the image display device according to claim 1,

wherein the weighting coefficient calculating unit calculates and outputs the weighting coefficient in accordance with a function having at least one coordinate of the display position of each display data on the display screen as an input value.

7. The drive circuit of the image display device according to claim 6, further comprising:

a register for storing a parameter of the function,

wherein the parameter can be externally changed.

8. A drive circuit of an image display device for displaying an image by irradiating a backlight on a display screen, the drive circuit comprising:

a backlight control unit which includes;

a histogram counting unit for acquiring a histogram by counting display data in units of frame of one or plural images and calculating a value of the display data at a specific upper position of the histogram;

a display data extension unit for extending each display data based on the value of the display data at the specific position; and

a backlight adjustment unit for adjusting a light emission amount of the backlight based on the value of the display data at the specific position,

wherein the histogram counting unit includes a weighting coefficient calculating unit for outputting a weighting coefficient corresponding to a content of display data of a predetermined region of the display screen, and counts the display data while adding the weighting coefficient to each display data, thereby acquiring the histogram.

9. The drive circuit of the image display device according to claim 8,

wherein the content of the display data of the predetermined region of the display screen is an icon image.

10. The drive circuit of the image display device according to claim 8,

wherein the content of the display data of the predetermined region of the display screen is an image including a large amount of high luminance component, an image having low influence on a display quality even if luminance resolution is lowered, an image with a small number of grayscales or luminance levels, or an image with small grayscale change or luminance change, in comparison to a content of display data other than the predetermined region of the display screen.

11. An image display method for displaying an image by irradiating a backlight on a display screen,

wherein a backlight control unit executes the processes of:

acquiring a histogram by counting display data in units of frame of one or plural images and calculating a value of the display data at a specific upper position of the histogram;

extending each display data based on the value of the display data at the specific position; and

adjusting a light emission amount of the backlight based on the value of the display data at the specific position, and

when acquiring the histogram by counting the display data, a weighting coefficient corresponding to a display position of each display data on the display screen is acquired, and the display data is counted while adding the weighting coefficient, thereby acquiring the histogram.

12. The image display method according to claim 11,

wherein, when acquiring the weighting coefficient, a weighting coefficient corresponding to a display region to which the display position of each display data on the display screen belongs is selected and acquired based on the weighting coefficient defined for each of a plurality of display regions on the display screen.

13. The image display method according to claim 11,

wherein, when acquiring the weighting coefficient, a weighting coefficient is calculated and acquired in accordance with a function having at least one coordinate of the display position of each display data on the display screen as an input value.