Organic light emitting diode display and method for controlling luminance thereof

Patent metadata

Field	Value
Publication number	US-10311798-B2
Application number	US-201514975093-A
Country	US
Kind code	B2
Filing date	Dec 18, 2015
Priority date	Dec 29, 2014
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

An organic light emitting diode display includes pixels in which an amount of current flowing in an organic light emitting diode of each pixel is determined depending on a difference between a data voltage and a reference voltage, a control signal generator differently generating a screen brightness control signal depending on a driving mode, a register adjusting unit independently adjusting a reference voltage register value and a gamma register value at each of red (R), green (G), and blue (B) pixels depending on the screen brightness control signal, a reference voltage generator generating the reference voltage of each of the R, G, and B colors based on the reference voltage register value, and a data voltage generator generating the data voltage of each of the R, G, and B colors based on the gamma register value.

First claim

What is claimed is:

1. An organic light emitting diode display comprising:
pixels each including an organic light emitting diode, an amount of current flowing in the organic light emitting diode being determined depending on a difference between a data voltage and a reference voltage;
a control signal generator configured to differently generate a screen brightness control signal depending on a driving mode;
a register adjusting unit configured to independently adjust a reference voltage register value and a gamma register value from a reference voltage default value and a gamma default value, respectively, at each of red (R), green (G), and blue (B) colors depending on the screen brightness control signal;
a reference voltage generator configured to generate the reference voltage of each of the R, G, and B colors based on the adjusted reference voltage register value; and
a data voltage generator configured to generate the data voltage of each of the R, G, and B colors based on the adjusted gamma register value,
wherein the control signal generator loads a plurality of bands, which correspond to some of digital brightness values input from a user and in which optical compensation is previously set on the gamma register value and the reference voltage register value of each band, and
wherein the register adjusting unit is further configured to:
in response to receiving the screen brightness control signal for an increase in brightness, increase the gamma register value of each of the R, G, and B colors from the gamma default value of a default band while decreasing the reference voltage register value of each of the R, G, and B colors from the reference voltage default value of the default band based on the digital brightness value.

2. The organic light emitting diode display of claim 1 , wherein the control signal generator generates the screen brightness control signal depending on one of a normal mode, a visibility improvement mode, and a mura prevention mode, and
wherein the band representing the second highest luminance among the plurality of bands is selected as the default band in the normal mode.

3. The organic light emitting diode display of claim 2 , wherein when the visibility improvement mode is directly selected by the user, the control signal generator selects a first target adjustment section from the default band to an uppermost band representing the highest luminance, senses a quantity of external light, updates digital illuminance information, and outputs the digital illuminance information as the screen brightness control signal.

4. The organic light emitting diode display of claim 3 , wherein the register adjusting unit increases the gamma register value of each of the R, G, and B colors from the gamma default value of the default band based on the digital illuminance information and decreases the reference voltage register value of each of the R, G, and B colors from the reference voltage default value of the default band based on the digital illuminance information.

5. The organic light emitting diode display of claim 2 , wherein when the digital brightness value increases from a digital brightness default value of the default band by the screen brightness control of the user, the control signal generator selects the visibility improvement mode as the driving mode, selects a first target adjustment section from the default band to an uppermost band representing the highest luminance, and outputs an increase amount of the digital brightness value as the screen brightness control signal.

6. The organic light emitting diode display of claim 5 , wherein the gamma register value and the reference voltage register value correspond to the increase amount of the digital brightness value.

7. The organic light emitting diode display of claim 6 , wherein the register adjusting unit divides a difference between R reference voltages belonging to the uppermost band and the default band by the increase amount of the digital brightness value, obtains a 1 step R reference voltage adjustment amount, and gradually decreases an R reference voltage register value by the 1 step R reference voltage adjustment amount at a predetermined interval,
wherein the register adjusting unit divides a difference between G reference voltages belonging to the uppermost band and the default band by the increase amount of the digital brightness value, obtains a 1 step G reference voltage adjustment amount, and gradually decreases a G reference voltage register value by the 1 step G reference voltage adjustment amount at a predetermined interval, and
wherein the register adjusting unit divides a difference between B reference voltages belonging to the uppermost band and the default band by the increase amount of the digital brightness value, obtains a 1 step B reference voltage adjustment amount, and gradually decreases a B reference voltage register value by the 1 step B reference voltage adjustment amount at a predetermined interval.

8. The organic light emitting diode display of claim 2 , wherein when the digital brightness value decreases from a digital brightness default value of the default band by the screen brightness control of the user, the control signal generator selects the mura prevention mode as the driving mode, selects a second target adjustment section from the default band to a lower band representing a luminance lower than the default band, and outputs a decrease amount of the digital brightness value as the screen brightness control signal.

9. The organic light emitting diode display of claim 8 , wherein the register adjusting unit decreases the gamma register value of each of the R, G, and B colors from the gamma default value of the default band and increases the reference voltage register value of each of the R, G, and B colors from the reference voltage default value of the default band, so that the gamma register value and the reference voltage register value correspond to the decrease amount of the digital brightness value.

10. The organic light emitting diode display of claim 9 , wherein the register adjusting unit divides a difference between R reference voltages belonging to the lower band and the default band by the decrease amount of the digital brightness value, obtains a 1 step R reference voltage adjustment amount, and gradually increases an R reference voltage register value by the 1 step R reference voltage adjustment amount at a predetermined interval,
wherein the register adjusting unit divides a difference between G reference voltages belonging to the lower band and the default band by the decrease amount of the digital brightness value, obtains a 1 step G reference voltage adjustment amount, and gradually increases a G reference voltage register value by the 1 step G reference voltage adjustment amount at a predetermined interval, and
wherein the register adjusting unit divides a difference between B reference voltages belonging to the lower band and the default band by the decrease amount of the digital brightness value, obtains a 1 step B reference voltage adjustment amount, and gradually increases a B reference voltage register value by the 1 step B reference voltage adjustment amount at a predetermined interval.

11. The organic light emitting diode display of claim 1 , wherein the reference voltage generator includes:
a first reference voltage generator configured to generate an R reference voltage depending on an R reference voltage register value;
a second reference voltage generator configured to generate a G reference voltage depending on a G reference voltage register value; and
a third reference voltage generator configured to generate a B reference voltage depe

Assignees

• Lg Display Co Ltd

Inventors

• Lee Hyunjae
• Park Taeyoung
• Shim Dongsup

Classifications

• G09G2330/028

  Generation of voltages supplied to electrode drivers in a matrix display other than LCD · CPC title

• G09G2320/08

  Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal · CPC title

• G09G2320/0673

  for control of gamma adjustment, e.g. selecting another gamma curve · CPC title

• G09G2300/0861

  with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes · CPC title

• G09G3/3233

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