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

• US 9,406,255 B2
• Filed: 01/14/2013
• Issued: 08/02/2016
• Est. Priority Date: 02/14/2008
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: JOLED Inc.
• Inventors: Isobe, Teppei, Hasegawa, Hiroshi, Abe, Hironobu
• Primary Examiner(s): Fry, Matthew
• Application Number:
  US13/740,534
• Publication Number:
  US 20130127929A1
• Time in Patent Office: 1,296 Days
• Field of Search: 345/102, 345204-208, 345/63, 345 76- 77, 345690-693, 348/447, 348/910, 348/687
• US Class Current: 1/1
• 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 condition setting device for a display device including a plurality of pixels, comprising a circuitry configured to:

select one of light emission modes including a still image mode and a motion image mode based on a specific condition;

set a light emission pattern within a predetermined range of a predetermined period for each of the plurality of pixels based on the selected light emission mode,

wherein, when the still image mode is selected, the light emission pattern is set so as to have exactly N (N>

=1) light emission pulses within the predetermined period,

whenever the motion image mode is selected and a total light emitting period length is greater than a threshold value and less than the width of the predetermined range, the light emission pattern is set so as to have exactly M (M>

=2) light emission pulses within the predetermined period, M being a different number than N, and

a duration of at least one of the M light emission pulses is different from a duration of another one of the M light emission pulses.

2. The lighting condition setting device according to claim 1, wherein the circuitry is configured to control a peak luminance level by changing the total lighting period length within the predetermined period.

3. The lighting condition setting device according to claim 2, wherein the circuitry is configured to change the total lighting period length by:

when the still image mode is selected, controlling respective lengths of each of the N light emission pulses, and

when the motion image mode is selected, controlling respective lengths of each of the M light emission pulses.

4. The lighting condition setting device according to claim 1, wherein the specific condition is a characteristic of an input image data.

5. The lighting condition setting device according to claim 4, wherein the characteristic of the input image data includes an average luminance level of the input image data.

6. The lighting condition setting device according to claim 4, wherein the characteristic of the input image data includes at least one of a presence or absence of motion, a motion image blur component level and a flicker component level.

7. The lighting condition setting device according to claim 1, wherein the predetermined period corresponds to one field period.

8. The lighting condition setting device according to claim 7, wherein N=1.

9. The lighting condition setting device according to claim 1, wherein N=1.

15. The lighting condition setting device according to claim 1,

wherein, whenever the motion image mode is selected and the total light emitting period length is greater than the threshold value and less than the width of the predetermined range, the M light emission pulses are arranged symmetrically about the center of the predetermined range.

16. The lighting condition setting device according to claim 15,

wherein, whenever the motion image mode is selected and the total light emitting period length equals the width of the predetermined range, the M light emission pulses merge together.

17. The lighting condition setting device according to claim 15,

wherein, whenever the motion image mode is selected and the total light emitting period length is greater than the threshold value but less than the width of the predetermined range, non-emission periods are disposed between adjacent ones of the M light emission pulses such that those of the non-emission periods that are comparatively closer to the center of the predetermined range are comparatively narrower than those of the non-emission periods that are further from the center of the predetermined range.

18. The light condition setting device according to claim 15,

wherein, whenever the motion image mode is selected and the total light emitting period length is greater than the threshold value but less than the width of the predetermined range, those of the M light emission pulses that are comparatively closer to the center of the predetermined range are comparatively wider than those of the M light emission pulses that are further from the center of the predetermined range.

10. A display device comprising:

a display panel including a plurality of pixels; and

a control circuitry operably coupled to the display device, the control circuitry being configured to;

select one of light emission modes including a still image mode and a motion image mode based on a specific condition; and

set a light emission pattern within a predetermined range of a predetermined period for each of the plurality of pixels based on the light emission mode,

wherein, when the still image mode is selected, the light emission pattern is set so as to have exactly N (N>

=1) light emission pulses within the predetermined period,

whenever the motion image mode is selected and a total light emitting period length is greater than a threshold value and less than the width of the predetermined range, the light emission pattern is set so as to have exactly M (M>

=2) light emission pulses within the predetermined period, M being a different number than N, and

a duration of at least one of the M light emission pulses is different from a duration of another one of the M light emission pulses.

11. The display device according to claim 10, wherein the control circuitry is configured to control a peak luminance level by changing the total lighting period length within the predetermined period.

12. The lighting condition setting device according to claim 11, wherein the circuitry is configured to change the total lighting period length by:

when the still image mode is selected, controlling respective lengths of each of the N light emission pulses, and

when the motion image mode is selected, controlling respective lengths of each of the M light emission pulses.

13. The lighting condition setting device according to claim 10, wherein the predetermined period corresponds to one field period.

14. The display device according to claim 10, further comprising a panel driver configured to supply a pulse signal in response to the control circuitry,

wherein each of the plurality of pixels includes a light emitting element and is configured to receive the pulse signal for controlling a drive current supplied to the light emitting element of the respective pixel.