(19)
(11) EP 1 437 706 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
10.10.2007 Bulletin 2007/41

(43) Date of publication A2:
14.07.2004 Bulletin 2004/29

(21) Application number: 04290015.9

(22) Date of filing: 06.01.2004
(51) International Patent Classification (IPC): 
G09G 3/28(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR
Designated Extension States:
AL LT LV MK

(30) Priority: 10.01.2003 EP 03290062

(71) Applicant: Thomson Licensing
92100 Boulogne-Billancourt (FR)

(72) Inventors:
  • Weitbruch, Sebastien
    78087 Monchweiler (DE)
  • Thebault, Cedric
    78050 Villingen (DE)
  • Correa, Carlos
    78056 Villingen-Schwenningen (DE)

(74) Representative: Ruellan-Lemonnier, Brigitte 
Thomson, European Patent Operations, 46 Quai Alphonse Le Gallo
92648 Boulogne Cedex
92648 Boulogne Cedex (FR)

   


(54) Method for optimizing brightness in a display device and apparatus for implementing the method


(57) The invention relates to a method for optimizing brightness in a display device having a plurality of luminous elements corresponding to the pixels of a picture, wherein the time duration of a video frame or video field is divided into a plurality of sub fields during which the luminous elements can be activated for light emission with sustain pulses corresponding to a sub field code word which is used for brightness control, the total number of sustain pulses being determined in view of a selected power mode function of picture load the method including the following steps:
- setting a threshold value in relation to the picture load,
- comparing, for a frame, the number of the current sustain pulse to said threshold value,
- if the number of the current sustain pulses is below the threshold value, the sustain pulses are generated at a fixed frequency,
- if the number of the current sustain pulses is above the threshold value, the sustain pulses are generated at an evolving frequency.
This invention applies mainly to PDP and all displays controlled by using a PWM.







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