Display device
AssigneeSanyo Electric Co., Ltd.
InventorYusuke Tsutsui
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Abstract
The display device of this invention has two types of DA converter for converting a digital image signal to an analog image signal; a first DA converter disposed in the peripheral area of a plurality of pixel elements and a second DA converter disposed within each of the pixel elements. The first DA converter converts the upper four-bit of a six-bit digital image signal and the second DA converter converts the remaining lower two-bit. This enables the simplification of the peripheral circuits of the pixel element, preventing size increase of the framing area of the display panel, while achieving the multiple-depth display with an increased number of the bits of the DA converter. In the display device with the built-in DA converter, the multiple-bit can be achieved while preventing the increase in the circuit size.
Claims9
A display device comprising:
- a plurality of pixel elements;
- a first DA converter disposed in a peripheral area of the pixel elements;
- and
- a second DA converter disposed within each of the pixel elements,
- wherein the first DA converter performs DA conversion on an m-bit portion of an n-bit digital image signal and the second DA converter performs DA conversion on a remaining (n−m)-bit portion of the digital image signal, a display image being formed by an analog image signal that is converted from the digital image signal by the first and second DA converters,
- the first DA converter comprises a reference voltage generating circuit generating a plurality of reference voltages based on the m-bit portion of the digital image signal, and a reference voltage selection circuit selecting a corresponding reference voltage pair from the plurality of the reference voltages based on the m-bit portion of the digital image signal, and
- the second DA converter comprises a plurality of capacitors each corresponding to a weighted capacitance value, a voltage supply circuit selectively supplying the reference voltage pair to electrodes of the plurality of the capacitors, and a charge transfer transistor supplying charges accumulated in the plurality of the capacitors to a pixel element electrode or a gate electrode of a driver transistor driving an electroluminescent element based on a timing signal.
A display device comprising:
- a plurality of pixel elements;
- a first DA converter disposed in a peripheral area of the pixel elements;
- and
- a second DA converter disposed within each of the pixel elements,
- wherein the first DA converter performs DA conversion on an n-bit portion of an n-bit digital image signal and the second DA converter performs DA conversion on a remaining (n−m)-bit portion of the digital image signal, a display image being formed by an analog image signal that is converted from the digital image signal by the first and second DA converters,
- the first DA converter comprises a reference data generating circuit sequentially generating reference digital data of n-bit with an increment, a step voltage generating circuit generating a step voltage pair that changes in synchronization with a change of the reference digital data and that corresponds to the reference digital data, an identification detection circuit detecting a matching of the digital image signal and the reference digital data and outputting an identification detection signal, and a gate circuit outputting the step voltage pair based on the identification detection signal.
Dependencies are inferred from the claim text.