US 6,686,699 B2 · Active matrix type display apparatus, active matrix type organic electroluminescence display apparatus, and driving methods thereof

Abstract

In an active matrix type organic EL display apparatus, a current bias circuit for feeding a data line with a current in a direction of canceling a writing current is provided for each data line. The current bias circuit includes: a converting unit supplied with information of a value of the driving current to be fed in a form of a current, for converting the supplied current into a form of a voltage; a retaining unit for retaining the voltage obtained by the conversion by the converting unit; and a driving unit for converting the voltage retained by the retaining unit into a current, and feeding the data line with the current as the driving current. The current bias circuit feeds, as a bias current, the driving current in the direction of canceling the brightness data current through each data line, and the value of the bias current is prevented from varying among the data lines. Thus high-speed writing of low brightness data including black data can be realized and an image without black floating can be displayed.

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Drawings

Claims20

Dependent claims

An active matrix type display apparatus comprising:

a pixel unit formed by arranging pixel circuits in a matrix manner, said pixel circuits each having an electrooptic device that changes brightness thereof according to a current flowing therein;
a data line driving circuit for supplying a writing current of a magnitude corresponding to brightness to each of said pixel circuits via a data line and thereby writing brightness data;
and
a current driving circuit provided for each data line for feeding the data line with a driving current in a direction of canceling said writing current;
wherein said current driving circuit includes:
a converting unit supplied with information of a value of the driving current to be fed in a form of a current, for converting the supplied current into a form of a voltage;
a retaining unit for retaining the voltage obtained by the conversion by said converting unit;
and
a driving unit for converting the voltage retained by said retaining unit into a current, and feeding the data line with the current as said driving current.

6 more elements

An active matrix type organic electroluminescence display apparatus comprising:

a pixel unit formed by arranging pixel circuits in a matrix manner, said pixel circuits each having an organic electroluminescence device with a first electrode, a second electrode, and an organic layer including a light emitting layer between the first electrode and the second electrode;
a data line driving circuit for supplying a writing current of a magnitude corresponding to brightness to each of said pixel circuits via a data line and thereby writing brightness data;
and
a current driving circuit provided for each data line for feeding the data line with a driving current in a direction of canceling said writing current;
wherein said current driving circuit includes:
a converting unit supplied with information of a value of the driving current to be fed in a form of a current, for converting the supplied current into a form of a voltage;
a retaining unit for retaining the voltage obtained by the conversion by said converting unit;
and
a driving unit for converting the voltage retained by said retaining unit into a current, and feeding the data line with the current as said driving current.

6 more elements

Dependencies are inferred from the claim text.

Description9,399 words

Summary3,550 words

#The present invention relates to an active matrix type display apparatus having an active device in each pixel and controlling display in the pixel unit by means of the active device, and a driving method thereof, and particularly to an active matrix type display apparatus using an electrooptic device that varies brightness according to a current flowing therein, an active matrix type organic EL display apparatus using an organic-material electroluminescence (hereinafter described as organic EL (electroluminescence)) device as the electrooptic device, and driving methods thereof.

#A liquid crystal display using a liquid crystal cell as a display device of a pixel, for example, has a large number of pixels arranged in a matrix manner, and controls light intensity in each pixel according to information of an image to be displayed, thereby effecting driving for image display. The same display driving is effected by an organic EL display using an organic EL device as a display device of a pixel and the like.

#Since the organic EL display is a so-called self-luminous type display using a light emitting device as a display device of a pixel, however, the organic EL display has advantages such as higher visibility of images, no need for a backlight, and a higher response speed as compared with the liquid crystal display. Moreover, brightness of each light emitting device is controlled by the value of a current flowing therein. That is, the organic EL display differs greatly from the liquid crystal display or the like of a voltage-controlled type, in that the organic EL device is of a current-controlled type.

Brief description of the drawings22 figures

#FIG. 1 shows a circuit configuration of a voltage writing type pixel circuit according to a conventional example;

#FIG. 2 is a block diagram showing an active matrix type display apparatus using the voltage writing type pixel circuit according to the conventional example;

#FIG. 3 shows a circuit configuration of a current writing type pixel circuit according to a first conventional example;

Detailed description5,438 words

#Preferred embodiments of the present invention will hereinafter be described in detail with reference to the drawings.

#[First Embodiment]

#FIG. 8 is a schematic diagram of a configuration of an active matrix type display apparatus according to a first embodiment of the present invention. Description in the following will be made by taking as an example a case where an organic EL device is used as an electrooptic device of each pixel, and a field-effect transistor, for example a polysilicon TFT is used as an active device of each pixel so that the present invention is applied to an active matrix type organic EL display apparatus obtained by forming the organic EL device on a substrate where the polysilicon TFT is formed.

Facts

Application

10/157,174Filed 29 May 2002

Priority

JP P2001-16189030 May 2001

Published

US 2002/0195964 A126 Dec 2002

Granted

3 Feb 2004

Term ended

29 May 2022

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification7 codes

G09G 3/3241
With pixel circuitry controlling the current through the light-emitting element: the current through the light-emitting element being set using a…
G09G 2300/0417
Matrix technologies: special arrangements specific to the use of low carrier mobility technology
G09G 2300/0842
Several active elements per pixel in active matrix panels: forming a memory circuit, e.g. a dynamic memory with one capacitor
G09G 2310/0262
Addressing, scanning or driving the display screen or processing steps related thereto: the addressing of the pixel, in a display other than an…

Active matrix type display apparatus, active matrix type organic electroluminescence display apparatus, and driving methods thereof

Life of this patent

Active matrix type display apparatus, active matrix type organic electroluminescence display apparatus, and driving methods thereof

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims20

Description9,399 words

Drawings

Classification7 codes

Life of this patent

Description9,399 words