Lighting period setting method, display panel driving method, backlight driving method, lighting condition setting device, semiconductor device, display panel and electronic equipment

• US 8,441,503 B2
• Filed: 02/10/2009
• Issued: 05/14/2013
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Isobe, Teppei, Hasegawa, Hiroshi, Abe, Hironobu
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): FRY, MATTHEW A
• Application Number:
  US12/320,959
• Publication Number:
  US 20090207193A1
• Time in Patent Office: 1,554 Days
• Field of Search: 345690-691, 345 76- 77, 345/102, 345/204
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• 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 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

Disclosed herein is a lighting period setting method for a display panel which permits control of the peak luminance level by controlling the total lighting period length which is the sum of all lighting periods per field period, the lighting period setting method including the steps of, calculating the average luminance level across the screen based on input image data, determining light emission mode based on the calculated average luminance level, and setting the number, arrangement and lengths of lighting periods per field period according to the setting conditions defined for the determined light emission mode so as to provide the peak luminance level which is set according to the input image data.

Claims

1. A lighting period setting method for a display panel which permits control of a peak luminance level for a field period by controlling a total lighting period length which is the sum of all lighting periods in the field period, the lighting period setting method comprising the steps of, for a given field period:

calculating a total average luminance level based on image data by averaging the luminance levels of pixels in N frames of an image to be displayed, wherein at least one of the N frames includes the frame to be displayed during the given field period;

setting the total lighting period length for the given field period based on the total average luminance level;

selecting a light emission mode for the given field period from a plurality of light emission modes based on the image data and the total average luminance level;

determining setting conditions for the light emission mode; and

setting, for the given field period, the number, arrangement and lengths of lighting periods according to the setting conditions and the total lighting period length so as to provide the peak luminance level,

wherein the plurality of light emission modes includes;

a still image mode;

a motion image emphasis mode;

a balanced mode; and

a flicker emphasis mode,

wherein the frame to be displayed during the given field period comprises a plurality of blocks, each block including a plurality of pixels, the method further comprising the steps of;

calculating a block average luminance level for each block by averaging the luminance levels of the pixels of the respective block;

detecting any blocks that have a block average luminance level greater than a predetermined luminance threshold value;

detecting any regions that are larger than a predetermined size threshold, wherein the regions consist of contiguous blocks that have been detected to have a block average luminance level greater than the predetermined luminance threshold value; and

detecting a flicker component level in the frame to be displayed during the given field period based on the size of the largest detected region and the number of detected regions; and

wherein, when the flicker emphasis mode is selected, the setting conditions are based on the detected flicker component level.

2. The lighting period setting method of claim 1, further comprising:

driving a pixel array section so as to provide the set lighting periods.

3. The lighting period setting method of claim 1, further comprising:

driving a backlight so as to provide the set lighting periods.

18. The lighting period setting method of claim 1, wherein the total lighting period length is set such that the magnitude of the total lighting period length is inversely related to the magnitude of the total average luminance level.

4. A lighting condition setting device comprising:

a luminance level calculation portion configured to calculate a total average luminance level for a given field period based on input image data by averaging the luminance levels of pixels in N frames of an image to be displayed, wherein at least one of the N frames includes the frame to be displayed during the given field period;

a total lighting period length setting unit configured to set the total lighting period length for the given field period based on the total average luminance level

a light emission mode selecting unit configured to select a light emission mode for the given field period from a plurality of light emission modes based on the image data and the total average luminance level; and

a lighting period setting unit configured to determine setting conditions for the light emission mode and set the number, arrangement and lengths of lighting periods per field period according to the setting conditions and the total lighting period length so as to provide a peak luminance level which is set according to the input image data,

wherein the plurality of light emission modes includes;

a still image mode;

a motion image emphasis mode;

a balanced mode; and

a flicker emphasis mode,

wherein the frame to be displayed during the given field period comprises a plurality of blocks, each block including a plurality of pixels, and the lighting period setting unit is configured to;

calculate a block average luminance level for each block by averaging the luminance levels of the pixels of the respective block;

detect any blocks that have a block average luminance level greater than a predetermined luminance threshold value;

detect any regions that are larger than a predetermined size threshold, wherein the regions consist of contiguous blocks that have been detected to have a block average luminance level greater than the predetermined luminance threshold value; and

detect a flicker component level in the frame to be displayed during the given field period based on the size of the largest detected region and the number of detected regions; and

wherein, when the flicker emphasis mode is selected, the lighting period setting unit determines the setting conditions based on the detected flicker component level.

5. The lighting condition setting device of claim 4, wherein the device is a semiconductor device.

6. A display panel whose peak luminance level is variably controlled by controlling the total lighting period length which is the sum of all lighting periods per field period, the display panel comprising:

a pixel array section having a pixel structure appropriate for active matrix driving;

a luminance level calculation portion configured to calculate a total average luminance level for a given field period based on input image data by averaging the luminance levels of pixels in N frames of an image to be displayed, wherein at least one of the N frames includes the frame to be displayed during the given field period;

a total lighting period length setting unit configured to set the total lighting period length for the given field period based on the total average luminance level

a light emission mode selecting unit configured to select a light emission mode for the given field period from a plurality of light emission modes based on the image data and the total average luminance level;

a lighting period setting unit configured to determine setting conditions for the light emission mode and set the number, arrangement and lengths of lighting periods per field period according to the setting conditions and the total lighting period length so as to provide a peak luminance level which is set according to the input image data; and

a panel drive section configured to drive the pixel array section so as to provide the set lighting periods,

wherein the plurality of light emission modes includes;

a still image mode;

a motion image emphasis mode;

a balanced mode; and

a flicker emphasis mode,

wherein the frame to be displayed during the given field period comprises a plurality of blocks, each block including a plurality of pixels, and the lighting period setting unit is configured to;

calculate a block average luminance level for each block by averaging the luminance levels of the pixels of the respective block;

detect any blocks that have a block average luminance level greater than a predetermined luminance threshold value;

detect any regions that are larger than a predetermined size threshold, wherein the regions consist of contiguous blocks that have been detected to have a block average luminance level greater than the predetermined luminance threshold value; and

detect a flicker component level in the frame to be displayed during the given field period based on the size of the largest detected region and the number of detected regions; and

wherein, when the flicker emphasis mode is selected, the lighting period setting unit determines the setting conditions based on the detected flicker component level.

7. The display panel of claim 6, wherein

the pixel array section has a pixel structure in which electro luminescence elements are arranged in a matrix form, and

the panel drive section sets the lighting periods of the electro luminescence elements.

8. The display panel of claim 6, further comprising:

a backlight drive section configured to drive a backlight source so as to provide the set period length.

9. Electronic equipment comprising:

a pixel array section having a pixel structure appropriate for active matrix driving, the pixel array section whose peak luminance level is variably controlled by controlling the total lighting period length which is the sum of all lighting periods per field period;

a luminance level calculation portion configured to calculate a total average luminance level for a given field period based on input image data by averaging the luminance levels of pixels in N frames of an image to be displayed, wherein at least one of the N frames includes the frame to be displayed during the given field period;

a total lighting period length setting unit configured to set the total lighting period length for the given field period based on the total average luminance level

a light emission mode selecting unit configured to select a light emission mode for the given field period from a plurality of light emission modes based on the image data and the total average luminance level; and

a lighting period setting unit configured to determine setting conditions for the light emission mode and set the number, arrangement and lengths of lighting periods per field period according to the setting conditions and the total lighting period length so as to provide a peak luminance level which is set according to the input image data;

a panel drive section configured to drive the pixel array section so as to provide the set lighting periods;

a system control section; and

an operation input section for the system control section,

wherein the plurality of light emission modes includes;

a still image mode;

a motion image emphasis mode;

a balanced mode; and

a flicker emphasis mode,

wherein the frame to be displayed during the given field period comprises a plurality of blocks, each block including a plurality of pixels, and the lighting period setting unit is configured to;

calculate a block average luminance level for each block by averaging the luminance levels of the pixels of the respective block;

detect any blocks that have a block average luminance level greater than a predetermined luminance threshold value;

detect any regions that are larger than a predetermined size threshold, wherein the regions consist of contiguous blocks that have been detected to have a block average luminance level greater than the predetermined luminance threshold value; and

detect a flicker component level in the frame to be displayed during the given field period based on the size of the largest detected region and the number of detected regions; and

wherein, when the flicker emphasis mode is selected, the lighting period setting unit determines the setting conditions based on the detected flicker component level.

10. The electronic equipment of claim 9 further comprising:

a backlight source whose peak luminance level is varied by controlling the total lighting period length which is the sum of all lighting periods per field period; and

a backlight drive section configured to drive the backlight source so as to provide the set period length.

11. A lighting period setting method for a display panel which permits control of a peak luminance level for a field period by controlling a total lighting period length which is the sum of all lighting periods in the field period, the lighting period setting method comprising the steps of, for a given field period:

calculating a total average luminance level based on image data by averaging the luminance levels of pixels in N frames of an image to be displayed, wherein at least one of the N frames includes the frame to be displayed during the given field period;

setting the total lighting period length for the given field period based on the total average luminance level;

selecting a light emission mode for the given field period from a plurality of light emission modes based on the image data and the total average luminance level;

determining setting conditions for the light emission mode;

setting, for the given field period, the number, arrangement and lengths of lighting periods according to the setting conditions and the total lighting period length so as to provide the peak luminance level; and

detecting a motion amount of the image to be displayed, based on the image signal data,

wherein the plurality of light emission modes includes;

a still image mode;

a motion image emphasis mode;

a balanced mode; and

a flicker emphasis mode,

wherein the still image mode is selected when the detected motion amount is less than a first predetermined value, and

wherein, when the detected motion amount is greater than the first predetermined value;

the motion image emphasis mode is selected when the calculated average luminance is less than a second predetermined value,

the balanced mode is selected when the calculated average luminance is greater than the second predetermined value and less than a third predetermined value, the third predetermined value being greater than the second predetermined value, and

the flicker emphasis mode is selected when the calculated average luminance is greater than the third predetermined value,

wherein the setting conditions are determined such that;

when the motion image emphasis mode is selected, the lighting periods are arranged within the given field period within a first range, the length of which is less than a first maximum value that is less than the length of the given field period;

when the balanced mode is selected, the lighting periods are arranged within the given field period within a second range, the length of which equals a second maximum value that is greater than the first maximum value and less than the length of the given field period; and

when the flicker emphasis mode is selected, the lighting periods are arranged within the given field period within a third range, the length of which is less than a third maximum value that is greater than the second maximum value and less than the length of the given field period,

wherein the motion emphasis mode comprises a plurality of motion emphasis setting levels and the flicker emphasis mode comprises a plurality of flicker emphasis setting levels, the method further comprising;

detecting a flicker component level;

when the motion emphasis mode has been selected, selecting a motion emphasis setting level from the plurality of motion emphasis setting levels according to the detected motion amount; and

when the flicker emphasis mode has been selected, selecting a flicker emphasis setting level from the plurality of flicker emphasis setting levels according to the detected flicker component level;

wherein the setting conditions are determined according to the selected motion emphasis setting level in the motion emphasis mode and according to the selected flicker emphasis setting level in the flicker emphasis mode.

12. The lighting period setting method of claim 11, wherein the frame to be displayed during the given field period comprises a plurality of blocks, each block including a plurality of pixels, the method further comprising the steps of:

calculating a block average luminance level for each block by averaging the luminance levels of the pixels of the respective block;

detecting any blocks that have a block average luminance level greater than a predetermined luminance threshold value;

detecting any regions that are larger than a predetermined size threshold, wherein the regions consist of contiguous blocks that have been detected to have a block average luminance level greater than the predetermined luminance threshold value; and

detecting the flicker component level based on at least one of the size of the largest detected region and the number of detected regions.

13. The lighting period setting method of claim 11, wherein the setting conditions are determined such that:

when the still image mode is selected,

when the total lighting period length is less than a still image threshold value, there is only one lighting period in the given field period, beginning at the start of the given field period, and

when the total lighting period length is greater than or equal to the still image threshold value, there are two lighting periods of equal length in the given field period, one of which begins at the start of the given field period and the other of which starts at 50% of the given field period.

14. The lighting period setting method of claim 11, wherein the setting conditions are determined such that when the motion image emphasis mode is selected,

there is only one lighting period in the given field period when a motion emphasis setting level corresponding to a largest detected motion amount is selected, and

there are M>

1 lighting periods in the given field period when a motion emphasis setting level corresponding to a detected motion amount smaller than the largest detected motion amount is selected, wherein

the M lighting periods are arranged symmetrically about the center of the first range with no-light periods in between each lighting period,

the length of each of the M lighting periods is set such that a first fixed symmetric ratio of lengths is maintained and the length of each lighting period closer to the center of the first range is greater than the lengths of any lighting period further from the center of the first range, and

the length of each no-light period that is interposed between lighting periods of the given field period is set such that a second fixed symmetric ratio of lengths is maintained and the length of each no-light period closer to the center of the first range is less than the lengths of any no-light period further from the center of the first range;

when the balanced mode is selected,

there are M>

1 lighting periods in the given field period, wherein

the M lighting periods are arranged symmetrically about the center of the second range with no-light periods in between each lighting period,

the length of each of the M lighting periods is set such that a third fixed symmetric ratio of lengths is maintained and the length of each lighting period closer to the center of the second range is greater than the lengths of any lighting period further from the center of the second range, and

the length of each no-light period that is interposed between lighting periods of the given field are equal; and

when the flicker emphasis mode is selected,

there are M>

1 lighting periods in the given field period, wherein

the M lighting periods are arranged symmetrically about the center of the third range with no-light periods in between each lighting period,

the length of each of the M lighting periods is set such that a fourth fixed symmetric ratio of lengths is maintained and the length of each lighting period closer to the center of the third range is greater than the lengths of any lighting period further from the center of the third range, and

the length of each no-light period that is interposed between lighting periods of the given field period is set such that a fifth fixed symmetric ratio of lengths is maintained and the length of each no-light period closer to the center of the third range is greater than or equal to the lengths of any no-light period further from the center of the first range;

wherein a largest term of the first ratio is larger than or equal to a largest term of the third ratio, which is larger than a largest term of the fourth ratio, such that for any given total lighting period, the longest lighting period of the motion image emphasis mode is longer than or equal to the longest lighting period of the balanced mode, which is longer than the longest lighting period of the flicker emphasis mode.

15. The lighting period setting method of claim 14, wherein the setting conditions are determined such that:

the length of the first range is larger when a motion emphasis setting level corresponding to a comparatively small detected motion amount is set than the length of the first range when a motion emphasis setting level corresponding to a comparatively large detected motion amount is set; and

the length of the third range is larger when a flicker emphasis setting level corresponding to a comparatively large detected flicker component level is set than the length of the third range when a flicker emphasis setting level corresponding to a comparatively small detected flicker component level is set.

16. The lighting period setting method of claim 14, wherein, whenever there are more than one lighting periods in the given field period, the first lighting period begins at the beginning of the corresponding range and the second lighting period ends at the end of the corresponding range.

17. The lighting period setting method of claim 11, wherein the first maximum value is 75% of the given field period, the second maximum value is 85% of the given field period, and the third maximum value is 90% of the given field period.