EL display device and electronic device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorJun Koyama
Life of this patent
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Abstract
An EL display device capable of producing a vivid multi-gradation color display, and an electronic device having the EL display device. An electric current supplied to an EL element 110 is controlled by providing a resistor 109 between a current control TFT 108 and the EL element 110 formed in a pixel 104, the resistor 109 having a resistance higher than the on-resistance of the current control TFT 108. The gradation display is executed by a time-division drive system which controls the emission and non-emission of light of the EL element 110 by time, preventing the effect caused by a dispersion in the characteristics of the current control TFT 108.
Claims29
An EL display device having a pixel unit, a data signal-side drive circuit and a gate signal-side drive circuit formed by TFTs over a substrate, wherein a resistor is provided between a current control TFT and an EL element formed in the pixel unit, and
- wherein a data signal input to the data signal-side drive circuit or to the gate signal-side drive circuit, is formed through;
- first means which divides a frame into n sub-frames (SF1, SF2, SF3, . . . , SF(n−1), SF(n)) corresponding to gradations of n bits (n is an integer of not smaller than 2);second means which selects an address period (Ta) and a sustain period (Ts:
- sustain periods Ts1, Ts2, Ts3, . . . , Ts (n−1), Ts(n) corresponding to SF1, SF2, SF3, . . . , SF(n−1), SF(n)) in said n sub-frames;
- and
- third means for so setting the sustain periods as to be Ts1:Ts2:Ts3:
- . . . :Ts(n−1):Ts(n)=20:2−1:2−2:
- . . . :2−(n−2):2−(n−1) in the n sub-frames.
An EL display device having a pixel unit, a data signal-side drive circuit and a gate signal-side drive circuit formed by TFTs over a substrate, wherein a resistor is provided between a current control TFT and an EL element formed in the pixel unit, the resistor exhibiting a resistance higher than the on-resistance of said current control TFT.
An EL display device having a pixel unit, a data signal-side drive circuit and a gate signal-side drive circuit formed by TFTs over a substrate, wherein a resistor is provided between a current control TFT and an EL element formed in the pixel unit, the resistor being formed integrally with the active layer of said current control TFT, at least the TFT of said data signal-side drive circuit comprising a semiconductor layer that exhibits an electron-ray diffraction image corresponding to an orientation {110}.
An electronic device using an EL display device as a display unit, wherein:
- the EL display device has a pixel unit, a data signal-side drive circuit and a gate signal-side drive circuit formed by TFTs;
- and
- a resistor is provided between a current control TFT and an EL element formed in the pixel unit, and
- wherein the active layer of the TFT is formed of a silicon film that exhibits an electron-ray diffraction image corresponding to an orientation {110}.
An electronic device using an EL display device as a display unit, wherein:
- the EL display device has a pixel unit, a data signal-side drive circuit and a gate signal-side drive circuit formed by TFTs;
- and
- a resistor is provided between a current control TFT and an EL element formed in the pixel unit, the resistor exhibiting a resistance higher than the on-resistance of the current control TFT.
An electronic device using an EL display device as a display unit, wherein:
- the EL display device has a pixel unit, a data signal-side drive circuit and a gate signal-side drive circuit formed by TFTs;
- and
- a resistor is provided between a current control TFT and an EL element formed in the pixel unit, the resistor being formed integrally with the active layer of the current control TFT,
- wherein at least the TFT of said data signal-side drive circuit comprises a semiconductor layer that exhibits an electron-ray diffraction image corresponding to an orientation {110}.
Dependencies are inferred from the claim text.