Display device with gradient conversion
View Patent ↗[Object] To realize a drive circuit where settling time (stabilization time) is shortened, without incurring marked increase in electric current consumed and marked increase in manufacturing costs. [Solution] A source drive circuit ( 1 ) has a digital gradient input converter ( 2 ) that converts gradient values of multiple image data (D 1 through Dn) that are gradient 1 into multiple gradient values, where the number of the multiple source amps (AM 1 through AMn) to which a gradient reference voltage (V 1 ) corresponding to gradient 1 is supplied, is reduced, and supplied to a DAC circuit ( 23 ).
1. A display device comprising:
a display panel;
a plurality of source amps that supply output signals to corresponding ones of a plurality of source lines of the display panel;
a gamma circuit that generates M (where M is a natural number of 2 or greater) different gradient reference voltages;
a digital/analog conversion circuit that selects one of the M gradient reference voltages supplied from the gamma circuit via each of M bus lines, based on each of input gradient values, and supplies to each of the plurality of source amps; and
a digital gradient input converter that converts the plurality of gradient values of a plurality of image data that are the same value into two or more gradient values that are mutually different values, and supplies to the digital/analog conversion circuit.
2. The display device according to claim 1 ,
wherein the digital gradient input converter converts part of the plurality of gradient values of a plurality of image data that are the same value to a gradient value that is one higher or a gradient value that is one lower.
3. The display device according to claim 1 ,
wherein the digital gradient input converter performs the conversion only
in a first case where the plurality of gradient values of a plurality of image data that are the same value are a gradient value that is N (where N is a natural number of 1 or greater and 3 and smaller) below a greatest gradient value or greater, or the greatest gradient value or smaller, and
in a second case where the plurality of gradient values of a plurality of image data that are the same value are a gradient value that is the smallest gradient value or greater, or N above a smallest gradient value or smaller.
4. The display device according to claim 1 ,
wherein the digital gradient input converter only performs the conversion in a case where a difference between the plurality of gradient values of a plurality of image data that are the same value and a plurality of gradient values of a plurality of image data supplied immediately prior is a predetermined value or greater.
5. The display device according to claim 1 ,
wherein an adjustment value for deciding a magnitude of conversion of the plurality of gradient values of a plurality of image data that are the same value is set in each of the plurality of source amps at the digital gradient input converter,
and wherein, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is the smallest gradient value or greater and the greatest gradient value or smaller, each of the plurality of gradient values of a plurality of image data that are the same value is converted by an amount corresponding to the adjustment value.
6. The display device according to claim 1 ,
wherein the digital gradient input converter has a plurality of registers,
wherein an adjustment value for deciding the magnitude of conversion of the plurality of gradient values of a plurality of image data that are the same value is set by each of the setting values of the plurality of registers,
and wherein, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is the smallest gradient value or greater and the greatest gradient value or smaller, each of the plurality of gradient values of a plurality of image data that are the same value is converted by an amount corresponding to the adjustment value.
7. The display device according to claim 1 ,
wherein the digital gradient input converter has a random number generator,
wherein an adjustment value for deciding the magnitude of conversion of the plurality of gradient values of a plurality of image data that are the same value is set by a random number generated by the random number generator,
and wherein, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is the smallest gradient value or greater and the greatest gradient value or smaller, each of the plurality of gradient values of a plurality of image data that are the same value is converted by an amount corresponding to the adjustment value.
8. The display device according to claim 1 ,
wherein an adjustment value for deciding the magnitude of conversion of the plurality of gradient values of a plurality of image data that are the same value is set by the digital gradient input converter performing dithering processing on each pixel region of a predetermined size configured of part of the plurality of pixels that display the plurality of image data,
and wherein, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is the smallest gradient value or greater and the greatest gradient value or smaller, each of the plurality of gradient values of a plurality of image data that are the same value is converted by an amount corresponding to the adjustment value.
9. The display device according to claim 8 ,
wherein the dithering processing includes
first dithering processing that is dithering processing performed on image data of odd frames in the plurality of image data, and
second dithering processing that is dithering processing performed on image data of even frames in the plurality of image data,
wherein the first dithering processing and the second dithering processing are different.
10. The display device according to claim 5 ,
wherein, at the digital gradient input converter, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is smaller than the smallest gradient value or greater than the greatest gradient value, each of the plurality of gradient values of a plurality of image data that are the same value is output without change, without being converted by an amount corresponding to the adjustment value.
11. The display device according to claim 5 ,
wherein, at the digital gradient input converter, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is smaller than the smallest gradient value, the smallest gradient value is output,
and wherein, in a case where a value obtained by adding the adjustment value and the plurality of gradient values of a plurality of image data that are the same value is greater than the greatest gradient value, the greatest gradient value is output.