White balance correction circuit and correction method for display apparatus that displays color image by controlling number of emissions or intensity thereof in accordance with plurality of primary color video signals
View Patent ↗A display apparatus, which displays a color image by controlling the number of emissions or the intensity thereof in accordance with primary color video signals input thereto, has a detection portion and a white balance correction portion. The detection portion is used to detect the number of emissions or the intensity, and the white balance correction portion is used to correct white balance by adjusting the amplitudes of the primary color video signals in accordance with the detected number of emissions or the detected intensity. Therefore, correct white balance can be maintained regardless of the number of emissions or the intensity of emission.
1. A display method of a plasma display apparatus carrying out color display by letting three primary color phosphors emit light in accordance with three input primary color video signals, the method comprising:
controlling a total number of sustain pulses to be applied in a frame in accordance with an average luminance level of the three primary color video signals for suppressing power consumption; and
controlling output grey levels of at least two colors among the three primary color video signals in input of a signal having a predetermined grey level so as to make the output grey levels larger in a case that the total number of sustain pulses in accordance with the average luminance level is a second number larger than a first number than in a case that the total number of sustain pulses is the first number, and
controlling the output grey levels, when the total number of sustain pulses is changed from the first number to the second number, so as to make a ratio of a change in the output grey level of a primary color video signal corresponding to a primary color of a phosphor, among the three phosphors, the energy conversion efficiency of which decreases most with increase in the number of emissions of the sustain pulses, larger than ratios of changes in the output grey levels of the other primary color video signals.
2. The display method of a plasma display apparatus according to claim 1 , further comprising:
carrying out control, when the average luminance level of the image inputted to the plasma display apparatus is large, to reduce the total number of sustain pulses.
3. The display method of a plasma display apparatus according to claim 1 , wherein altering the output grey levels of the primary color video signals is not changing the total number of sustain pulses to be applied in the frame but changing sub-frames to be lit in the frame.
4. A plasma display apparatus carrying out color display by letting three primary color phosphors emit light in accordance with three input primary color video signals, the apparatus comprising:
means for changing a total number of sustain pulses to be applied in a frame in accordance with an average luminance level of an input image;
output-grey-level adjusting means for altering the output-grey-level of the primary color video signals when the total number of sustain pulses in accordance with the average luminance level is changed from a first number to a second number larger than the first number, in accordance with the total number of sustain pulses so as to make output grey levels of at least two colors among the three primary color video signals in input of a signal having a predetermined grey level larger; and
driving means for driving a plasma display panel by primary color video signals with the output grey levels adjusted by the output-grey-level adjusting means to display an image,
wherein, when the total number of sustain pulses in the frame is changed from the first number to the second number, the output-grey-level adjusting means adjusts white balance of a display image by controlling the output grey levels so as to make a ratio of a change in an the output grey level of a primary color video signal corresponding to a primary color of a phosphor, among the three phosphors, the energy conversion efficiency of which decreases most with increase in the number of emissions of the sustain pulses, larger than ratios of changes in the output grey levels of the other primary color video signals.
5. The plasma display apparatus according to claim 4 , wherein altering the output grey levels of the primary color video signals is not changing the total number of sustain pulses to be applied in the frame but changing sub-frames to be lit in the frame.
6. The display method of a plasma display apparatus according to claim 2 , wherein
the input three primary color video signal s are a red signal, a green signal, and a blue signal,
the blue signal is a signal having the smallest decrease of the energy conversion efficiency with increase in the number of emissions of the sustain pulses, and
even when the total number of sustain pulses is changed from the first number to the second number, a luminance ratio of three colors represented by the red signal, the green signal, and the blue signal is controlled so as to be a predetermined value.
7. The plasma display apparatus according to claim 4 , wherein,
the input three primary color video signals are a red signal, a green signal, and a blue signal,
the blue signal is a signal having the smallest decrease of the energy conversion efficiency with increase in the number of emissions of the sustain pulses, and
even when the total number of sustain pulses is changed from the first number to the second number, a luminance ratio of three colors represented by the red signal, the green signal, and the blue signal is controlled so as to be a predetermined value.