US 2001/0033263 A1 · Gray-scale image display device that can reduce power consumption when writing data

An image display device including a panel having a first electrode which extends in a first direction to write image data and a second electrode which extends in a second direction to select a display line, wherein a field period is divided into a plurality of sub-field periods that each have a predetermined luminance weight, and a gray-scale image for the field period is displayed by (a) writing sub-field image data of each sub-field period obtained by dividing input image data of the field period into the plurality of sub-field periods, into the panel through the first electrode and the second electrode, and (b) sustaining an illumination state of ON or OFF in each cell for each sub-field period using luminance equivalent to a luminance weight of each sub-field period, based on the written sub-field image data, the image display device comprising

an image changing unit for changing a part of sub-field image data of a predetermined sub-field period, so that a total number of charges and discharges performed on the first electrode when writing the sub-field image data becomes smaller.

An image display device including a panel having a first electrode which extends in a first direction to write image data and a second electrode which extends in a second direction to select a display line, wherein a field period is divided into a plurality of sub-field periods that each have a predetermined luminance weight, and a gray-scale image for the field period is displayed by (a) writing sub-field image data of each sub-field period obtained by dividing input image data of the field period into the plurality of sub-field periods, into the panel through the first electrode and the second electrode, and (b) sustaining an illumination state of ON or OFF in each cell for each sub-field period using luminance equivalent to a luminance weight of each sub-field period, based on the written sub-field image data, the image display device comprising

an image changing unit for changing, when a part of sub-field image data of a predetermined sub-field period has a higher spatial frequency than a predetermined value, the part of the sub-field image data so that
(a) cells corresponding to pixels which form the part of the sub-field image data are uniformly OFF in the predetermined sub-field period, and uniformly one of ON and OFF in a sub-field period having a smaller luminance weight than the predetermined sub-field period, if a luminance weight of the predetermined sub-field period is not the smallest luminance weight of the plurality of sub-field periods, and
(b) the cells corresponding to the pixels which form the part of the sub-field image data are uniformly one of ON and OFF in the predetermined sub-field period, if the luminance weight of the predetermined sub-field period is the smallest luminance weight.

An image display device including a panel having a first electrode which extends in a first direction to write image data and a second electrode which extends in a second direction to select a display line, wherein a field period is divided into a plurality of sub-field periods that each have a predetermined luminance weight, and a gray-scale image for the field period is displayed by (a) writing sub-field image data of each sub-field period obtained by dividing input image data of the field period into the plurality of sub-field periods, into the panel through the first electrode and the second electrode, and (b) sustaining an illumination state of ON or OFF in each cell for each sub-field period using luminance equivalent to a luminance weight of each sub-field period, based on the written sub-field image data, the image display device comprising:

image data storing means for storing sub-field image data of each sub-field period;
pattern detecting means for reading sub-field image data of a predetermined sub-field period from the image data storing means, and detecting whether a part of the read sub-field image data has a specific pattern that causes a substantial increase in power consumption when writing the sub-field image data;
and
image changing means for, when the part of the sub-field image data having the specific pattern is detected by the pattern detecting means,
(a) reading the sub-field image data of the predetermined sub-field period from the image data storing means, changing the part of the sub-field image data so that cells corresponding to pixels which form the part of the sub-field image data are uniformly OFF in the predetermined sub-field period, and storing the changed sub-field image data back into the image data storing means, and
(b) reading sub-field image data of a sub-field period whose luminance weight is smaller than the predetermined sub-field period from the image data storing means, changing a corresponding part of the read sub-field image data so that the cells corresponding to the pixels which form the corresponding part of the sub-field image data are uniformly ON in the sub-field period, and storing the changed sub-field image data back into the image data storing means.

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An image display device including a panel having a first electrode which extends in a first direction to write image data and a second electrode which extends in a second direction to select a display line, wherein a field period is divided into a plurality of sub-field periods that each have a predetermined luminance weight, and a gray-scale image for the field period is displayed by (a) writing sub-field image data of each sub-field period obtained by dividing input image data of the field period into the plurality of sub-field periods, into the panel through the first electrode and the second electrode, and (b) sustaining an illumination state of ON or OFF in each cell for each sub-field period using luminance equivalent to a luminance weight of each sub-field period, based on the written sub-field image data, the image display device comprising:

image data storing means for storing sub-field image data of each sub-field period;
pattern detecting means for reading sub-field image data of a predetermined sub-field period from the image dada storing means, and detecting whether a part of the read sub-field image data has a specific pattern that causes a substantial increase in power consumption when writing the sub-field image data;
comparing means for comparing, when the part of the sub-field image data having the specific pattern is detected by the pattern detecting means, a number of pixels which form the part of the sub-field image data with a predetermined number;
image changing means for (a) reading, when the number of pixels is no smaller than the predetermined number, the sub-field image data of the predetermined sub-field period from the image data storing means, (b) changing the read sub-field image data so that cells corresponding to all pixels of the sub-field image data are uniformly ON in the predetermined sub-field period, and (c) storing the changed sub-field image data back into the image data storing means;
and
luminance controlling means for changing a luminance weight of the predetermined sub-field period, so that average luminance of the sub-field image data in the predetermined sub-field period is kept within a certain range.

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Gray-scale image display device that can reduce power consumption when writing data

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Gray-scale image display device that can reduce power consumption when writing data

Life of this patent

Abstract

Claims19