US 11,114,031 B2Granted

Display device and method for driving same

AssigneeSharp Kabushiki Kaisha

InventorTetsuya Ueno

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Abstract

The present disclosure discloses a current-driven display device that uses an internal compensation method and can display a good-quality image with no bright dots that are not included in intended display content. In a pixel circuit of an organic EL display device, a voltage of a gate terminal of a drive transistor is initialized before the voltage of a data signal line is written to a holding capacitor via the diode-connected drive transistors. At this time, an initialization voltage is applied to the gate terminal via a display element initialization transistor, a second light emission control transistor, and a threshold compensation transistor. By initializing the gate terminal with a configuration not including an initialization transistor provided between the gate terminal and an initialization voltage supply line as in the related art, voltage drop at the gate terminal due to leakage current of the transistor in an off state is suppressed.

Claims13

Dependent claims

A display device including a plurality of data signal lines, a plurality of scanning signal lines intersecting the plurality of data signal lines, a plurality of light emission control lines individually corresponding to the plurality of scanning signal lines, and a plurality of pixel circuits arranged in a matrix along the plurality of data signal lines and the plurality of scanning signal lines, the display device comprising:

first and second power source lines;
an initialization voltage supply line;
a data signal line drive circuit configured to drive the plurality of data signal lines;
a scanning signal line drive circuit configured to selectively drive the plurality of scanning signal lines;
and
a light emission control circuit configured to drive the plurality of light emission control lines,
each pixel circuit comprising:
a display element driven by a current;
a holding capacitor configured to hold a voltage used for controlling a drive current of the display element;
a drive transistor configured to control a drive current of the display element according to a voltage held by the holding capacitor;
a write control switching element;
a threshold compensation switching element;
first and second light emission control switching elements;
and
an initialization switching element,
wherein a first conduction terminal of the drive transistor is connected to any one of the plurality of data signal lines via the write control switching element, and the first power source line via the first light emission control switching element,
a second conduction terminal of the drive transistor is connected to a first terminal of the display element via the second light emission control switching element,
a control terminal of the drive transistor is connected to the first power source line via the holding capacitor, and the second conduction terminal via the threshold compensation switching element,
the first terminal of the display element is connected to the initialization voltage supply line via the initialization switching element, and a second terminal of the display element is connected to the second power source line, and
when a holding voltage of the holding capacitor is to be initialized, the threshold compensation switching element, the second light emission control switching element, and the initialization switching element are controlled to an on state, and the write control switching element and the first light emission control switching element are controlled to an off state.

17 more elements

A method for driving a display device including a plurality of data signal lines, a plurality of scanning signal lines intersecting the plurality of data signal lines, a plurality of light emission control lines individually corresponding to the plurality of scanning signal lines, first and second power source lines, an initialization voltage supply line, and a plurality of pixel circuits arranged in a matrix along the plurality of data signal lines and the plurality of scanning signal lines, the method for driving a display device comprising:

an initialization step of initializing each pixel circuit,
wherein each pixel circuit comprises:
a display element driven by a current;
a holding capacitor configured to hold a voltage used for controlling a drive current of the display element;
a drive transistor configured to control a drive current of the display element according to a voltage held by the holding capacitor;
a write control switching element;
a threshold compensation switching element;
first and second light emission control switching elements;
and
an initialization switching element,
a first conduction terminal of the drive transistor is connected to any one of the plurality of data signal lines via the write control switching element, and the first power source line via the first light emission control switching element,
a second conduction terminal of the drive transistor is connected to a first terminal of the display element via the second light emission control switching element,
a control terminal of the drive transistor is connected to the first power source line via the holding capacitor, and the second conduction terminal via the threshold compensation switching element, the first terminal of the display element is connected to the initialization voltage supply line via the initialization switching element, and a second terminal of the display element is connected to the second power source line, and
in the initialization step, when a holding voltage of the holding capacitor is to be initialized, the threshold compensation switching element, the second light emission control switching element, and the initialization switching element are controlled to an on state, and the write control switching element and the first light emission control switching element are controlled to an off state.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/981,660Filed 28 Mar 2018
Published: US 2021/0110769 A115 Apr 2021
Granted: 7 Sep 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

G09G 3/3233
Using an active matrix: with pixel circuitry controlling the current through the light-emitting element
G09G 3/3266
Organic, e.g. using organic light-emitting diodes [OLED]: details of drivers for scan electrodes
G09G 3/3275
Organic, e.g. using organic light-emitting diodes [OLED]: details of drivers for data electrodes
G09G 2300/0819
Several active elements per pixel in active matrix panels: used for counteracting undesired variations, e.g. feedback or autozeroing

Family

US 2021/0110769 A1Pre-grant publication · published 15 Apr 2021
US 11,114,031 B2This patent

From the US filing history. Foreign family members aren’t listed.

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