Flicker quantification system and method of driving the same

Patent metadata

Field	Value
Publication number	US-10770001-B2
Application number	US-201916542125-A
Country	US
Kind code	B2
Filing date	Aug 15, 2019
Priority date	Oct 2, 2018
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A flicker quantification system includes a display device driven in units of reference periods having a first frame for writing data and at least one second frame for holding data. A luminance measurer generates luminance data by measuring a luminance of a display during the reference period. A voltage measurer measures a voltage of a photo sensor corresponding to light emitted. First voltage data representing an accumulation amount of voltage during the first frame and second voltage data representing an accumulation amount of voltage during the at least one second frame is generated. A processor calculates a flicker index value representing a ratio of a measured luminance difference to a just noticeable difference, based on the luminance data, the first voltage data, and the second voltage data. The measured luminance difference may represent the difference between a luminance during the first frame and a luminance during the second frame.

First claim

What is claimed is:

1. A flicker quantification system comprising:
a display device configured to be driven according to a unit of a reference period comprising a first frame for writing data and at least one second frame for holding the data;
a luminance measurer configured to generate luminance data by measuring a luminance of a display surface of the display device during the reference period;
a voltage measurer configured to measure a voltage of a photo sensor corresponding to light emitted from the display surface, and to generate first voltage data representing an accumulation amount of the voltage during the first frame and second voltage data representing an accumulation amount of the voltage during the at least one second frame; and
a processor configured to calculate a flicker index value representing a ratio of a measured luminance difference to a just noticeable difference, based on the luminance data, the first voltage data, and the second voltage data,
wherein the measured luminance difference represents the difference between a luminance during the first frame and a luminance during the at least one second frame.

2. The flicker quantification system of claim 1 , wherein the display device comprises:
pixels coupled to first scan lines, second scan lines, data lines, and emission control lines;
a first scan driver configured to be driven according to a first frequency, the first scan driver being configured to supply first scan signals to the first scan lines;
a second scan driver configured to be driven according to a second frequency different from the first frequency, the second scan driver being configured to supply second scan signals to the second scan lines;
a data driver driven according to the second frequency, the data driver being configured to supply data signals to the data lines; and
an emission driver configured to supply emission control signals to the emission control lines according to the first frequency.

3. The flicker quantification system of claim 2 , wherein the processor is configured to calculate the flicker index value according to:
J FI={( A 1− A 2)*LDAT* P} /{JND*(( A 1− A 2)* Q+A 2* P )},

wherein JFI denotes the flicker index value, JND denotes the just noticeable difference, P denotes the first frequency, Q denotes the second frequency, A 1 denotes the first voltage data, A 2 denotes the second voltage data, and LDAT denotes the luminance data.

4. The flicker quantification system of claim 3 , wherein the display device is configured to sequentially display images corresponding to a plurality of gray levels,
wherein the processor is configured to perform a first operation of calculating the flicker index value for each of the plurality of gray levels.

5. The flicker quantification system of claim 4 , wherein the second scan driver is configured to be sequentially driven according to a plurality of second frequencies,
wherein the processor is configured to perform a second operation of performing the first operation for each of the plurality of second frequencies.

6. The flicker quantification system of claim 5 , wherein the processor is configured to generate a quantification table obtained by sorting the flicker index values for each of the plurality of gray levels and each of the plurality of second frequencies.

7. The flicker quantification system of claim 6 , wherein the first scan driver is configured to be sequentially driven according to a plurality of first frequencies,
wherein the processor is configured to perform the second operation for each of the plurality of first frequencies.

8. The flicker quantification system of claim 7 , wherein the processor is configured to generate a quantification table by sorting the flicker index values for each of the plurality of gray levels, each of the plurality of first frequencies, and each of the plurality of second frequencies.

9. The flicker quantification system of claim 1 , wherein the processor is configured to calculate the flicker index value according to:
J FI={( A 1− A 2)*LDAT }/(JND* A 2),

wherein JFI denotes the flicker index value, JND denotes the just noticeable difference, A 1 denotes the first voltage data, A 2 denotes the second voltage data, and LDAT denotes the luminance data.

10. The flicker quantification system of claim 2 , wherein the first frequency is larger than the second frequency.

11. The flicker quantification system of claim 10 , wherein the first frequency is 60 Hz.

12. A method of driving a flicker quantification system, the method comprising:
generating luminance data by measuring a luminance of a display surface of a display device during a reference period, wherein the display device is driven in the unit of the reference period, wherein the reference period comprises a first frame for writing data and at least one second frame for holding the data;
measuring a voltage of a photo sensor corresponding to light emitted from the display surface, and generating first voltage data representing an accumulation amount of the voltage during the first frame and second voltage data representing an accumulation amount of the voltage during the at least one second frame; and
calculating a flicker index value representing a ratio of a measured luminance difference to a just noticeable difference, based on the luminance data, the first voltage data, and the second voltage data,
wherein the measured luminance difference represents the difference between a luminance during the first frame and a luminance during the at least one second frame.

13. The method of claim 12 , wherein the display device comprises:
pixels coupled to first scan lines, second scan lines, data lines, and emission control lines;
a first scan driver configured to be driven according to a first frequency, the first scan driver being configured to supply first scan signals to the first scan lines;
a second scan driver configured to be driven according to a second frequency different from the first frequency, the second scan driver being configured to supply second scan signals to the second scan lines;
a data driver configured to be driven according to the second frequency, the data driver being configured to supply data signals to the data lines; and
an emission driver configured to supply emission control signals to the emission control lines according to the first frequency.

14. The method of claim 13 , wherein the display device sequentially displays images corresponding to a plurality of gray levels,
wherein the method further comprises performing a first operation of calculating the flicker index value for each of the plurality of gray levels.

15. The method of claim 14 , wherein the second scan driver is sequentially driven according to a plurality of second frequencies,
wherein the method further comprises performing a second operation of performing the first operation for each of the plurality of second frequencies.

16. The method of claim 15 , further comprising generating a quantification table obtained by sorting the flicker index values for each of the plurality of gray levels and each of the plurality of second frequencies.

17. The method of claim 13 , wherein the flicker index value is calculated using:
J FI={( A 1− A 2)*LDAT* P} /{JND*(( A 1− A 2)* Q+A 2* P )},

wherein JFI denotes the flicker index value, JND denotes the just noticeable difference, P denotes the first frequency, Q denotes the second frequency, A 1 denotes the first voltage data, A 2 denotes the second voltage data, and LDAT denotes the luminance data.

Assignees

• Samsung Display Co Ltd

Inventors

• Park Se Hyuk
• Nam Hui
• Lee Hyo Jin

Classifications

• G09G2320/029

  by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel · CPC title

• G09G2320/0247

  Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes · CPC title

• G09G3/006 Primary

  Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309) · CPC title

• G09G2360/145

  the light originating from the display screen · CPC title

• G09G2300/0842

  forming a memory circuit, e.g. a dynamic memory with one capacitor · CPC title