US 10,490,128 B1 · Electronic devices having low refresh rate display pixels with reduced sensitivity to oxide transistor threshold voltage

Abstract

A display may have an array of organic light-emitting diode display pixels operating at a low refresh rate. Each display pixel may include a drive transistor coupled in series with one or more emission transistors and a respective organic light-emitting diode (OLED). A semiconducting-oxide transistor may be coupled between a drain terminal and a gate terminal of the drive transistor to help reduce leakage during low-refresh-rate display operations. A silicon transistor may be further interposed between the semiconducting-oxide transistor and the gate terminal of the drive transistor. One or more capacitor structures may be coupled to the source terminal and/or the drain terminal of the semiconducting-oxide transistor to reduce rebalancing current that might flow through the semiconducting-oxide transistor as it is turned off. Configured in this way, any emission current flowing through the OLED will be insensitive to any potential drift in the threshold voltage of the semiconducting-oxide transistor.

Claims26

Dependent claims

A display pixel, comprising:

a light-emitting diode;
a drive transistor coupled in series with the light-emitting diode, wherein the drive transistor comprises a drain terminal, a gate terminal, and a source terminal;
a transistor of a first semiconductor type coupled between the drain terminal and the gate terminal of the drive transistor, wherein the transistor of the first semiconductor type is configured to reduce leakage at the gate terminal of the drive transistor, and wherein the transistor of the first semiconductor type has a threshold voltage;
and
a transistor of a second semiconductor type different than the first semiconductor type, wherein the transistor of the second semiconductor type is interposed between transistor of the first semiconductor type and the gate terminal of the drive transistor, and wherein the transistor of the second semiconductor type is configured to reduce the sensitivity of an emission current that flows through the light-emitting diode to the threshold voltage of the transistor of the first semiconductor type.

2 more elements

A method of operating a display pixel, comprising:

during an emission phase, using a drive transistor in the display pixel to convey an emission current to a light-emitting diode in the display pixel, wherein the drive transistor comprises a drain terminal and a gate terminal;
using a transistor of a first semiconductor type coupled between the drain terminal and the gate terminal of the drive transistor to reduce leakage at the gate terminal of the drive transistor during the emission phase, wherein the transistor of the first semiconductor type has a threshold voltage;
and
using a transistor of a second semiconductor type interposed between the transistor of the first semiconductor type and the gate terminal of the drive transistor to reduce the sensitivity of the emission current to the threshold voltage of the transistor of the first semiconductor type.

1 more element

Dependencies are inferred from the claim text.

Electronic devices having low refresh rate display pixels with reduced sensitivity to oxide transistor threshold voltage

Life of this patent

Electronic devices having low refresh rate display pixels with reduced sensitivity to oxide transistor threshold voltage

Life of this patent

Abstract

Claims26