Method and apparatus for enhancing peak luminance on plasma display panel
View Patent ↗To provide a plasma display device which implements a peak luminance higher than prior art, reduces the power dissipation, improves the smoothness of gradation display, and conducts clear display suitable especially for TV display. By setting a plurality of APL levels according to the average value of the scene brightness, and by shortening a sustaining pulse period and increasing the number of sustaining pulses of each sub-field in APL levels having small APL, the peak luminance is raised. Further, by making the sustaining pulse period long in APL levels having large APL requiring large discharge light emission power, the light emission efficiency is improved and the maximum power dissipation is reduced. The luminance distribution in the scene when the APL level is small is detected. On the basis of that information, setting of the number of sustaining pulses and the sustaining pulse period is changed in the same APL level. As a result, the peak luminance is increased, and the gradation smoothness in the dark scene is improved.
1. A peak luminance enhance (PLE) method for plasma display panel, which comprises the steps of:
determining a plurality of luminance levels (LLs), according to pixel data of a scene to be displayed;
determining a number of sustaining discharge (SD) pulses for each of said LLs;
determining a period of said SD pulses in case where said LL is lower than a predetermined value to be shorter than that of said SD pulses in case where said LL is greater than the predetermined value.
2. The PLE method according to claim 1 , wherein two or more values are determined as said predetermined value.
3. A peak luminance enhance (PLE) method for plasma display panel, which comprises the steps of:
determining a plurality of luminance levels (LLs), according to pixel data of a scene to be displayed;
detecting a luminance distribution which has the luminance level lower than the predetermined value;
deriving a maximum luminance of a portion having maximum luminance on the basis of said luminance distribution; and
making the number of sustaining discharge (SD) pulses greater, as said maximum luminance becomes higher.
4. The PLE method according to claim 3 , wherein a period of said SD pulses is made shorter, as said maximum luminance becomes higher.
5. A peak luminance enhance (PLE) method for plasma display panel, which comprises the steps of:
determining a plurality of luminance levels (LLs), according to pixel data of a scene to be displayed;
determining a number of sustaining discharge (SD) pulses for each of said LLs; and
determining a period of said SD pulses in case where said LL is lower than a predetermined value to be shorter than a period of said SD pulses in case where said LL is higher than said predetermined value,
detecting a luminance distribution which has said LL lower than said predetermined value;
deriving a maximum luminance of a portion having said maximum luminance on the basis of said luminance distribution; and
determining the number of SD pulses to be greater, as said maximum luminance becomes higher.
6. The PLE method according to claim 5 , wherein a period of said SD pulses is made shorter, as said maximum luminance becomes higher.
7. The PLE method according to claim 1 , wherein said period of said SD pulses in case where said LL is greater than said predetermined value is at least 4 microseconds.
8. The PLE method according to claim 4 , wherein a period of said SD pulses in case where said LL is greater than said predetermined value is at least 4 microseconds.
9. The PLE method according to claim 6 , wherein a period of said SD pulses in case where said LL is greater than said predetermined value is at least 4 microseconds.
10. The PLE method according to claim 1 , wherein a ratio of the maximum period of said SD pulse to the minimum of said SD pulse is greater than or equal to 1.3 and smaller than or equal to 5.0.
11. The PLE method according to claim 4 , wherein a ratio of the maximum period of said SD pulse to the minimum of said SD pulse is greater than or equal to 1.3 and smaller than or equal to 5.0.
12. The PLE method according to claim 6 , wherein a ratio of the maximum period of said SD pulse to the minimum of said SD pulse is greater than or equal to 1.3 and smaller than or equal to 5.0.
13. The PLE method according to claim 7 , wherein a ratio of the maximum period of said SD pulse to the minimum of said SD pulse is greater than or equal to 1.3 and smaller than or equal to 5.0.
14. The PLE method according to claim 8 , wherein a ratio of the maximum period of said SD pulse to the minimum of said SD pulse is greater than or equal to 1.3 and smaller than or equal to 5.0.
15. The PLE method according to claim 9 , wherein a ratio of the maximum period of said SD pulse to the minimum of said SD pulse is greater than or equal to 1.3 and smaller than or equal to 5.0.
16. The PLE method according to claim 1 , wherein said SD pulses are stopped in case where said LL is equal to or lower than said prescribed value.
17. The PLE method according to claim 3 , wherein said SD pulses are stopped in case where said LL is equal to or lower than said prescribed value.
18. The PLE method according to claim 5 , wherein said SD pulses are stopped in case where said LL is equal to or lower than said prescribed value.
19. The PLE method according to claim 1 , wherein said SD pulses for a sub-field are stopped in case where said LL of display data in said sub-field is equal to or lower than said prescribed value.
20. The PLE method according to claim 3 , wherein said SD pulses for a sub-field are stopped in case where said LL of display data in said sub-field is equal to or lower than said prescribed value.
21. The PLE method according to claim 5 , wherein said SD pulses for a sub-field are stopped in case where said LL of display data in said sub-field is equal to or lower than said prescribed value.
22. The PLE method according to claim 16 , wherein pre-discharge pulses are stopped.
23. The PLE method according to claim 17 , wherein pre-discharge pulses are stopped.
24. The PLE method according to claim 18 , wherein pre-discharge pulses are stopped.
25. The PLE method according to claim 19 , wherein pre-discharge pulses are stopped.
26. The PLE method according to claim 20 , wherein pre-discharge pulses are stopped.
27. The PLE method according to claim 21 , wherein pre-discharge pulses are stopped.
28. A peak luminance enhancement (PLE) apparatus for a plasma display panel, wherein an average picture level (APL)of a displayed picture is detected, and a period of sustaining discharge (SD) pulse is determined on the basis of said APL, which comprises:
a data processing means for processing digital RGB signal;
a sub-field selection means for selecting sub-fields on the basis of the output from said data processing means;
an APL detection means for detecting said APL on the basis of said digital RGB signal and for determining a plurality of luminance levels (LLs) for each of said sub-fields;
an SD pulse period setting means for setting up periods of said SD pulse for each of said sub-fields on the basis of the output from said APL detection means; and
an SD pulse number setting means for setting up numbers for each of said sub-fields on the basis of the output from said APL detection means,
wherein:
said numbers of SD pulses are determined for each of said LLs, and
said period of said SD pulses in case where said LLs is lower than a predetermined value is shorter than a period of said SD pulses in case where said LL is greater than the predetermined value; and
two or more values are determined as said predetermined value.
29. The PLE apparatus according to claim 28 , which further includes a maximum luminance detection means for detecting a maximum luminance on the basis of a luminance distribution for portions of which LLs are lower than said predetermined value, wherein:
said number of sustaining discharge pulses is made large as the maximum luminance becomes higher;
said period of said SD pulses is made shorter, as said maximum luminance becomes higher.
30. The PLE apparatus according to claim 28 , wherein a period of said SD pulses in case where the luminance level is higher than the predetermined value is made at least 4 microseconds.
31. The PLE apparatus according to claim 28 , wherein a ratio MAX/MIN of a maximum value MAX of the period of the sustaining discharge pulses to a minimum value MIN thereof is in the range of 1.3 to 5.0.
32. The PLE apparatus according to claim 28 , wherein the SD pulses are stopped in case where said LL is equal to or lower than said prescribed value.
33. The PLE apparatus according to claim 28 , wherein the SD pulses for a sub-field are stopped in case where said LL of display data in the sub-field is equal to or lower than a prescribed value.
34. The PLE apparatus according to claim 28 , wherein pre-discharge pulses are stopped.