LCD with adaptive overdrive
View Patent ↗A LCD device includes a LCD module, a thermal sensor, an operating device and a frame memory. The operating device includes first and second comparators, one-dimensional first to fourth lookup tables and an operator. The LCD device further includes a selector/data-generator which differentially generates an overdrive output and a prediction output according to outputs of the first comparator, the second comparator and the operator, depending on one of four conditions including a first condition that a start level and an end level are consistent; a second condition that a level of the output of the operator is greater than a predefined maximum; a third condition that the level is less than a predefined minimum; and a fourth condition that the level lies between the predefined maximum and the predefined minimum.
1. A liquid crystal display (LCD) device, comprising:
a LCD module;
a thermal sensor, disposed in the display module;
an operating device calculating and outputting an overdrive voltage and a predicted value of a sub-frame of the LCD module according to a start level and an end level of an image data; and
a frame memory storing the predicted value as the start level which is then outputted to the operating device;
wherein the operating device comprises:
a first comparator for determining whether the start level and the end level are consistent or not;
a first lookup table being one-dimensional and showing the relationship between levels and normalized offsets which are used for standardizing curves associated with squares of voltages corresponding to the levels;
a second lookup table being one-dimensional and showing the relationship between levels and squares of voltages corresponding to the levels;
an operator for obtaining an intermediate output value for overdrive, which correlates to a specified square of voltage, by referring to the start level, the end level, and values of the first and second lookup tables;
a second comparator for determining whether an output of the operator is greater than a predefined maximum, is less than a predefined minimum, or is an intermediate value;
a third lookup table being one-dimensional and used for calculating an overdrive value to be referred to according to outputs of the first and second comparators; and
a fourth lookup table being one-dimensional and used for calculating a predicted value to be referred to according to the outputs of the first and second comparator; and
wherein the first to fourth lookup tables are dynamically updated in response to a value outputted by the thermal sensor; and
the LCD device being characterized in comprising a selector/data-generator which differentially generates an overdrive output and a prediction output according to the outputs of the first comparator, the second comparator and the operator, depending on one of four conditions including:
a first condition that the start level and the end level are consistent;
a second condition that the intermediate output value for overdrive is greater than the predefined maximum;
a third condition that the intermediate output value for overdrive is less than the predefined minimum; and
a fourth condition that the intermediate output value for overdrive lies between the predefined maximum and the predefined minimum.
2. The LCD device according to claim 1 wherein the second lookup table stores therein squares of voltages corresponding to levels, which are normalized and applied to liquid crystal, and the third lookup table stores therein levels corresponding to squares of voltages which are normalized and applied to liquid crystal.
3. The LCD device according to claim 2 wherein the fourth lookup table stores therein the relationship between start levels and prediction levels.
4. The LCD device according to claim 2 wherein the first lookup table shows the addition of normalized offsets to squares of voltages as defined in the second lookup table corresponding to levels, and the abscissa and ordinate of the fourth lookup table are obtained by switching the abscissa and ordinate of the first lookup table.
5. The LCD device according to claim 1 wherein the fourth lookup table stores therein the relationship between start levels and prediction levels.
6. The LCD device according to claim 1 wherein the first lookup table shows the addition of normalized offsets to squares of voltages as defined in the second lookup table corresponding to levels, and the abscissa and ordinate of the fourth lookup table are obtained by switching the abscissa and ordinate of the first lookup table.