US 7,256,774 B1Granted

Display device

AssigneeSharp Kabushiki Kaisha

InventorsTakahiro Senda, Takao Muroi

Life of this patent

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Abstract

Each pixel includes: a first wiring for allowing a current to flow to an organic EL element; a first TFT element, provided in series to the organic EL element so as to be positioned in a path for allowing the current to flow from the first wiring, which has a control terminal for controlling conductance of the first TFT element; a second TFT element, provided in series to the organic EL element and the first TFT element so as to be positioned in the path, which has a control terminal for allowing/disallowing conduction; a capacitor which applies a voltage corresponding to stored electric charge to the control terminal of the first TFT element as a control voltage for controlling the conductance of the first TFT element; a third TFT element, provided in a path for supplying the electric charge to the capacitor, which has a control terminal for allowing/disallowing conduction, said third TFT element causing the capacitor to store the electric charge by disallowing conduction; a second wiring which applies a control voltage to the control terminal of the second TFT element; and a third wiring which applies a control voltage to the control terminal of the third TFT element. Thus, it is possible to enlarge an area of a transparent electrode.

Claims8

Dependent claims

A display device, setting a value of a current allowed to flow to an electro-optic element of at least one pixel so as to drive the electro-optic element on the basis of the current, wherein the pixel includes:

a first wiring for allowing the current to flow to the electro-optic element;
a first active element, provided in series to the electro-optic element so as to be positioned in a path for allowing the current to flow from the first wiring to the electro-optic element, which has a control terminal for controlling conductance of the first active element;
a second active element, provided in series to the electro-optic element and the first active element so as to be positioned in the path, which has a control terminal for allowing/disallowing conduction;
an electric charge retaining section for storing electric charge so as to apply a voltage corresponding to thus stored electric charge to the control terminal of the first active element as a control voltage for controlling the conductance of the first active element;
a third active element, provided in a path for supplying the electric charge to the electric charge retaining section, which has a control terminal for allowing/disallowing conduction, said third active element causing the electric charge retaining section to retain the electric charge by disallowing conduction, so that the pixel has only said first, second and third active elements;
wherein a current source circuit and a voltage source circuit are connected to the first wiring in a switchable manner;
a second wiring for applying a control voltage for allowing/disallowing conduction to the control terminal of the second active element;
and
a third wiring for applying a control voltage for allowing/disallowing conduction to the control terminal of the third active element.

6 more elements

A display device, setting a value of a current allowed to flow to an electro-optic element of each pixel so as to drive the electro-optic element on the basis of the current, wherein the pixel includes:

a firstly-ordered wiring for allowing the current to flow to the electro-optic element;
a firstly-ordered active element, provided in series to the electro-optic element so as to be positioned in a path for allowing the current to flow from the firstly-ordered wiring to the electro-optic element, which has a control terminal for controlling conduction of the firstly-ordered active element;
an electric charge retaining section for storing electric charge so as to apply a voltage corresponding to thus stored electric charge to the control terminal of the firstly-ordered active element as a control voltage for controlling the conductance of the firstly-ordered active element;
a secondly-ordered active element, provided in a path for supplying the electric charge to the electric charge retaining section, which has a control terminal for allowing/disallowing conduction, said secondly-ordered active element causing the electric charge retaining section to retain the electric charge by disallowing conduction, so that each pixel has only said firstly-ordered active element, said secondly-ordered active element and a thirdly-ordered active element;
wherein a current source circuit and a voltage source circuit are connected to the firstly-ordered wiring in a switchable manner;
a secondly-ordered wiring for applying a control voltage for allowing/disallowing conduction to the control terminal of the secondly-ordered active element;
and
a thirdly-ordered wiring for providing a reference voltage, which is a fraction of the voltage corresponding to the electric charge stored in the electric charge retaining section, to the electric charge retaining section.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/700,463Filed 5 Nov 2003
Priority: JP 2002-3538285 Dec 2002
Granted: 14 Aug 2007
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G09G 3/3233
Using an active matrix: with pixel circuitry controlling the current through the light-emitting element
G09G 3/2022
By time modulation using two or more time intervals: using sub-frames
G09G 2300/0465
Pixel structures: improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum…
G09G 2300/0842
Several active elements per pixel in active matrix panels: forming a memory circuit, e.g. a dynamic memory with one capacitor