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US 7,742,020 B2Granted
Display device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorJun Koyama
Life of this patent
Estimating the term…
Abstract
A signal line driving circuit which includes a digital signal sampling circuit, a storage circuit, a time setting circuit and a constant current circuit, is fabricated of TFTs on an insulating substrate which is made of the same substance as that of a pixel portion substrate. Thus, in a passive type EL display device, the problem of a distortion in the case of bonding the signal line driving circuit onto the pixel portion substrate can be eliminated. Besides, in an active type EL display device, each pixel is constructed of one transistor and an EL element. Thus, the aperture factor of the EL display device is enlarged.
Claims24
A personal computer having an electroluminescent display device, said display device comprising:
- a plurality of signal lines;
- a plurality of pixels, each pixel including one thin film transistor and an electroluminescent element, wherein a source electrode of the thin film transistor is connected with one of the plurality of signal lines;
- and
- a signal line driving circuit configured to input signals to the plurality of signal lines,
- wherein the signal line driving circuit comprises:
- a digital signal sampling circuit configured to sample inputted digital gradation signals over one line period;
- a storage circuit configured to store therein sampled digital gradation signals for one line period;
- a time setting circuit configured to convert stored digital gradation signals into pulses of corresponding durations by comparing the stored digital gradation signals with counter signals inputted to the time setting circuit;
- and
- a constant current circuit configured to receive signals from the time setting circuit and output currents of constant value to the signal lines for the durations of the pulses.
7 more elements
A personal computer having an active type electroluminescent display device, said display device comprising:
- a plurality of source signal lines;
- a plurality of gate signal lines;
- a plurality of pixels, each pixel including one thin film transistor and an electroluminescent element, wherein a source electrode of the thin film transistor is connected with one of the plurality of signal lines and a gate electrode of the thin film transistor is connected with one of the plurality of gate signal lines;
- a source signal line driving circuit configured to input signals to the plurality of source signal lines;
- and
- a gate signal line driving circuit configured to input signals to the plurality of gate signal lines,
- wherein the source signal line driving circuit comprises:
- a digital signal sampling circuit configured to sample inputted digital gradation signals over one line period;
- a storage circuit configured to store therein sampled digital gradation signals for one line period;
- a time setting circuit configured to compare the stored digital gradation signals with counter signals inputted to the time setting circuit and to convert the stored digital gradation signals into pulses of corresponding durations;
- and
- a constant current circuit configured to receive signals from the time setting circuit and output currents of constant value to the source signal lines for the durations of the pulses.
9 more elements
A camera having an electroluminescent display device, said display device comprising:
- a plurality of signal lines;
- a plurality of pixels, each pixel including one thin film transistor and an electroluminescent element, wherein a source electrode of the thin film transistor is connected with one of the plurality of signal lines;
- a signal line driving circuit configured to input signals to the plurality of signal lines,
- wherein the signal line driving circuit comprises:
- a digital signal sampling circuit configured to sample inputted digital gradation signals over one line period;
- a storage circuit configured to store therein sampled digital gradation signals for one line period;
- a time setting circuit configured to convert stored digital gradation signals into pulses of corresponding durations by comparing the stored digital gradation signals with counter signals inputted to the time setting circuit;
- and
- a constant current circuit configured to receive signals from the time setting circuit and output currents of constant value to the signal lines for the durations of the pulses.
6 more elements
A camera having an active type electroluminescent display device, said display device comprising:
- a plurality of source signal lines;
- a plurality of gate signal lines;
- a plurality of pixels, each pixel including one thin film transistor and an electroluminescent element, wherein a source electrode of the thin film transistor is connected with one of the plurality of signal lines and a gate electrode of the thin film transistor is connected with one of the plurality of gate signal lines;
- a source signal line driving circuit configured to input signals to the plurality of source signal lines;
- and
- a gate signal line driving circuit configured to input signals to the plurality of gate signal lines,
- wherein the source signal line driving circuit comprises:
- a digital signal sampling circuit configured to sample inputted digital gradation signals over one line period;
- a storage circuit configured to store therein sampled digital gradation signals for one line period;
- a time setting circuit configured to compare the stored digital gradation signals with counter signals inputted to the time setting circuit and to convert the stored digital gradation signals into pulses of corresponding durations;
- and
- a constant current circuit configured to receive signals from the time setting circuit and output currents of constant value to the source signal lines for the durations of the pulses.
9 more elements
A portable telephone having an electroluminescent display device, said display device comprising:
- a plurality of signal lines;
- a plurality of pixels, each pixel including one thin film transistor and an electroluminescent element, wherein a source electrode of the thin film transistor is connected with one of the plurality of signal lines;
- and
- a signal line driving circuit configured to input signals to the plurality of signal lines,
- wherein the signal line driving circuit comprises:
- a digital signal sampling circuit configured to sample inputted digital gradation signals over one line period;
- a storage circuit configured to store therein sampled digital gradation signals for one line period;
- a time setting circuit configured to convert stored digital gradation signals into pulses of corresponding durations by comparing the stored digital gradation signals with counter signals inputted to the time setting circuit;
- and
- a constant current circuit configured to receive signals from the time setting circuit and output currents of constant value to the signal lines for the durations of the pulses.
7 more elements
A portable telephone having an active type electroluminescent display device, said display device comprising:
- a plurality of source signal lines;
- a plurality of gate signal lines;
- a plurality of pixels, each pixel including one thin film transistor and an electroluminescent element, wherein a source electrode of the thin film transistor is connected with one of the plurality of signal lines and a gate electrode of the thin film transistor is connected with one of the plurality of gate signal lines;
- a source signal line driving circuit configured to input signals to the plurality of source signal lines;
- and
- a gate signal line driving circuit configured to input signals to the plurality of gate signal lines,
- wherein the source signal line driving circuit comprises:
- a digital signal sampling circuit configured to sample inputted digital gray scale signals over one line period;
- a storage circuit configured to store therein sampled digital gray scale signals for one line period;
- a time setting circuit configured to compare the stored digital gray scale signals with counter signals inputted to the time setting circuit and to convert the stored digital gray scale signals into pulses of corresponding durations;
- and
- a constant current circuit configured to receive signals from the time setting circuit and output currents of constant value to the source signal lines for the durations of the pulses.
9 more elements
Dependencies are inferred from the claim text.