Luminance controlling unit, light-emitting unit, and luminance controlling method

Patent metadata

Field	Value
Publication number	US-11069293-B2
Application number	US-201816048828-A
Country	US
Kind code	B2
Filing date	Jul 30, 2018
Priority date	Aug 22, 2017
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A luminance controlling unit includes a luminance controller that controls luminance of a pixel array including pixels each including a current-driven self-luminescent element. The luminance controller performs, on the basis of an image signal, a dynamic control of a duty ratio of a voltage pulse and a potential difference between a first voltage and a second voltage. The first voltage is outputted from a first voltage source adjacent to an anode of the corresponding self-luminescent element, and the second voltage is outputted from a second voltage source adjacent to a cathode of the corresponding self-luminescent element. The duty ratio is directed to controlling of light emission and light extinction of the self-luminescent element.

First claim

What is claimed is:

1. A luminance controlling unit comprising:
a luminance controller that controls luminance of a pixel array, the pixel array including pixels each including a current-driven self-luminescent element,
the luminance controller performing, on a basis of an image signal, a dynamic control of a duty ratio of a voltage pulse that is output by a first voltage source and a potential difference between the voltage pulse and a second voltage that is output by a second voltage source that is different from the first voltage source, the duty ratio being directed to controlling of light emission and light extinction of the current-driven self-luminescent element,
wherein the luminance controller causes, on the basis of the image signal, the potential difference to be less than a default potential difference, and causes the duty ratio to be greater than a default duty ratio,
wherein the default duty ratio is an initial duty ratio of the voltage pulse that is output by the first voltage source,
wherein, to perform the dynamic control of the duty ratio of the voltage pulse that is output by the first voltage source and the potential difference between the voltage pulse and the second voltage, the luminance controller is further configured to determine a corrected duty ratio,
wherein the corrected duty ratio is the default duty ratio multiplied by a compensation factor,
wherein the compensation factor is based on the default potential difference divided by a third potential difference, the default potential difference is between a default output voltage of the first voltage source and a default output voltage of the second voltage source, and the third potential difference is between a corrected output voltage of the first voltage source and the default output voltage of the second voltage source, and
wherein the compensation factor is less than or equal to 100 divided by the default duty ratio.

2. The luminance controlling unit according to claim 1 , wherein the luminance controller controls the duty ratio within a range in which a power consumption per frame image in the pixel array does not exceed a reference power consumption per frame image.

3. The luminance controlling unit according to claim 1 , wherein
each of the pixels includes the current-driven self-luminescent element, a driving transistor that controls a driving current flowing in the current-driven self-luminescent element, and a switching transistor that writes a signal voltage based on the image signal into a gate of the driving transistor, and
the luminance controller applies, to a current path including the driving transistor and the current-driven self-luminescent element, the voltage pulse that has the duty ratio that is greater than the default duty ratio and of which peak value is the potential difference.

4. The luminance controlling unit according to claim 3 , wherein the luminance controller performs the dynamic control of the potential difference and the duty ratio after an automatic brightness limiting operation, the automatic brightness limiting operation limiting the driving current by correcting the image signal to cause the signal voltage to be less than the signal voltage based on the image signal.

5. The luminance controlling unit according to claim 4 , wherein the luminance controller controls the duty ratio within a range in which a power consumption per frame image in the pixel array does not exceed a reference power consumption per frame image, the reference power consumption being a power consumption in a condition where the automatic brightness limiting operation is not performed.

6. A light-emitting unit comprising:
a pixel array that includes pixels each including a current-driven self-luminescent element; and
a luminance controller that controls luminance of the pixel array,
the luminance controller performing, on a basis of an image signal, a dynamic control of a duty ratio of a voltage pulse that is output by a first voltage source and a potential difference between the voltage pulse and a second voltage that is output by a second voltage source that is different from the first voltage source, the duty ratio being directed to controlling of light emission and light extinction of the current-driven self-luminescent element,
wherein the luminance controller causes, on the basis of the image signal, the potential difference to be less than a default potential difference, and causes the duty ratio to be greater than a default duty ratio,
wherein the default duty ratio is an initial duty ratio of the voltage pulse that is output by the first voltage source,
wherein, to perform the dynamic control of the duty ratio of the voltage pulse that is output by the first voltage source and the potential difference between the voltage pulse and the second voltage, the luminance controller is further configured to determine a corrected duty ratio,
wherein the corrected duty ratio is the default duty ratio multiplied by a compensation factor,
wherein the compensation factor is based on the default potential difference divided by a third potential difference, the default potential difference is between a default output voltage of the first voltage source and a default output voltage of the second voltage source, and the third potential difference is between a corrected output voltage of the first voltage source and the default output voltage of the second voltage source, and
wherein the compensation factor is less than or equal to 100 divided by the default duty ratio.

7. A luminance controlling method comprising:
controlling, with a luminance controller, a luminance of a pixel array, the pixel array including pixels each including a current-driven self-luminescent element; and
dynamically controlling, on a basis of an image signal and with the luminance controller, a duty ratio of a voltage pulse that is output by a first voltage source and a potential difference between the voltage pulse and a second voltage that is output by a second voltage source that is different from the first voltage source, the duty ratio being directed to controlling of light emission and light extinction of the current-driven self-luminescent element,
wherein dynamically controlling the duty ratio of the voltage pulse that is output by the first voltage source and the potential difference between the voltage pulse and the second voltage on the basis of the image signal further includes causing, on the basis of the image signal, the potential difference to be less than a default potential difference and the duty ratio to be greater than a default duty ratio,
wherein the default duty ratio is an initial duty ratio of the voltage pulse that is output by the first voltage source,
wherein dynamically controlling the duty ratio of the voltage pulse that is output by the first voltage source and the potential difference between the voltage pulse and the second voltage further includes determining a corrected duty ratio,
wherein the corrected duty ratio is the default duty ratio multiplied by a compensation factor,
wherein the compensation factor is based on the default potential difference divided by a third potential difference, the default potential difference is between a default output voltage of the first voltage source and a default output voltage of the second voltage source, and the third potential difference is between a corrected output voltage of the first voltage source and the default output voltage of the second voltage source, and
wherein the compensation factor is less than or equal to 100 divided by the default duty ratio.

8. The luminance controlling method according to claim 7 , wherein dynamically controlling the duty ratio of the voltage pulse that is output by the

Assignees

• Joled Inc

Inventors

• Ishii Hiroaki
• Isobe Teppei

Classifications

• G09G2320/064

  by time modulation of the brightness of the illumination source · CPC title

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title

• G09G3/3258 Primary

  with pixel circuitry controlling the voltage across the light-emitting element · CPC title

• G09G2330/023

  using energy recovery or conservation · CPC title

• G09G3/3233

  with pixel circuitry controlling the current through the light-emitting element · CPC title