Patent ID: 7391399

Claim:
A display device comprising: a display part having a plurality of pixels; a plurality of video lines which apply gray-scale voltages to the plurality of pixels; and a drive part which supplies gray-scale voltages corresponding to display data to the plurality of video lines; wherein display data is display data of n bits, and the drive part includes a gray-scale voltage generating circuit, assuming m (m being an integer of 2 or more) as a lower-order bit in accordance with n-bit display data, generates M pieces of gray-scale voltages where the gray scale number with respect to the gray-scale voltages is discontinuous, a decoder circuit which selects two neighboring gray-scale voltages out of M pieces of gray-scale voltages based on data of upper-order (n-m) bits in accordance with n-bit display data, and an output amplifying circuit which generates gray-scale voltages between two gray-scale voltages from two gray-scale voltages selected by the decoder circuit based on the data of lower-order m bits in accordance with n-bit display data and supplies the gray-scale voltages to the video lines; wherein the output amplifying circuit includes an operational amplifier which has k (k≧3) pieces of non-inverting input terminals and one inverting input terminal, and a switching part which is provided between the decoder circuit and k pieces of non-inverting input terminals of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to an output terminal of the operational amplifier, two gray-scale voltages which are selected by the decoder circuit are inputted to the switching part, and the switching part, based on the data of lower-order m bits in accordance with n-bit display data, selects two inputted gray-scale voltages and applies two inputted gray-scale voltages to k pieces of non-inverting input terminals of the operational amplifier such that the gray-scale voltages applied to the k pieces of non-inverting input terminals of the operational amplifier assume a given combination; and wherein the operational amplifier includes a differential amplifying circuit which constitutes an input stage, the differential amplifying circuit which constitutes the input stage includes at least one inverting-side transistor which has a control terminal thereof connected to the inverting input terminal, and k pieces of non-inverting-side transistors which constitute a differential pair with the at least one inverting-side transistor and have respective control terminals thereof connected to the respective non-inverting input terminals, and the weighting of an electrode width of control electrodes is applied to the k pieces of non-inverting-side transistors and at least one inverting-side transistor.