Display device manufacturing method

• US 10,157,558 B2
• Filed: 05/22/2015
• Issued: 12/18/2018
• Est. Priority Date: 06/05/2014
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: JOLED Inc.
• Inventors: Saito, Nobuo
• Primary Examiner(s): Yang, Nan-Ying
• Application Number:
  US15/314,291
• Publication Number:
  US 20170193871A1
• Time in Patent Office: 1,306 Days
• CPC Class Codes: G09F 9/00 Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the variable information is permanently attached to a movable support G09F11/00; abacus G06C1/00; slide-rules G06G1/00
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/048 using evaluation of the usage time
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/006 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 Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: H10K 50/00 Organic light-emitting devices integrated devices or assemblies of multiple devices H10K59/00, H10K65/00; organic semiconductor lasers H01S5/36
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 71/70 Testing, e.g. accelerated lifetime tests
• CPC Class Codes: H10K 71/831 Aging

Abstract

A display device manufacturing method includes: lighting up a display device for a predetermined period; measuring, as first brightness, brightness of the display device at a start of lighting; measuring, as second brightness, brightness of the display device when the predetermined period has elapsed; calculating a deterioration rate of the second brightness with respect to the first brightness; and discriminating the display device as a defective item if the deterioration rate is greater than a threshold value.

Claims

1. A display device manufacturing method comprising:

lighting-up a target display device, at a first time point;

measuring, as first brightness, brightness of the target display device at a second time point after the lighting-up of the target display device at the first time point;

measuring, as second brightness, brightness of the target display device at a third time point when a predetermined period has elapsed from the second time point;

terminating, after measuring the second brightness, lighting of the target display device;

after terminating the lighting of the target display device, calculating, using the first brightness measured at the second time point and the second brightness measured at the third time point, a deterioration rate of the second brightness with respect to the first brightness;

determining that the target display device is defective when the deterioration rate is greater than a threshold value; and

determining that the target display device is conforming when the deterioration rate is less than or equal to the threshold value.

2. The display device manufacturing method according to claim 1,

wherein in the lighting-up of the target display device during the predetermined period, the target display device is lit up at maximum brightness.

3. The display device manufacturing method according to claim 1,

wherein the lighting-up of the target display device during the predetermined period is performed in one of a lighting inspection of a panel before shipment and aging before shipment.

4. The display device manufacturing method according to claim 1,

wherein the target display device is an organic electroluminescent (EL) display device including red, green, and blue pixels that are disposed two-dimensionally, and

in the lighting-up of the target display device during the predetermined period, the target display device is lit up in white by lighting-up the red, green, and blue pixels simultaneously over an entire screen.

5. The display device manufacturing method according to claim 1,

wherein the target display device includes red, green, and blue pixels that are disposed two-dimensionally, and

in the lighting-up of the target display device during the predetermined period, the target display device is lit up by sequentially switching among the red, green, and blue pixels over an entire screen so that a lighting period for each color is the predetermined period.

6. The display device manufacturing method according to claim 1,

wherein the target display device includes red, green, and blue pixels that are disposed two-dimensionally,

in the lighting-up of the target display device during the predetermined period, a white band image having a predetermined width is displayed and scrolled through a screen, and

a sum of lighting periods for each of the red, green, and blue pixels is the predetermined period.

7. The display device manufacturing method according to claim 1,

wherein the target display device includes red, green, and blue pixels that are disposed two-dimensionally,

in the lighting-up of the target display device during the predetermined period, color band images in individual colors of the red, green, and blue pixels each having a predetermined width are displayed and scrolled through a screen, and

a sum of lighting periods for each of the red, green, and blue pixels is the predetermined period.

8. The display device manufacturing method according to claim 1,

wherein the first brightness is an average of brightness values at two or more areas of the target display device at the second time point, and

wherein the second brightness is an average of brightness values at the two or more areas of the target display device at the third time point.

9. The display device manufacturing method according to claim 8,

wherein a size of the two or more areas of the target display device is at least 1 centimeter (cm) in diameter.

10. The display device manufacturing method according to claim 8,

wherein one area of the two or more areas of the target display device is located at a central region of the target display device.

11. The display device manufacturing method according to claim 1,

wherein the deterioration rate is calculated by dividing a sum of the first brightness and the second brightness, by the first brightness.

12. The display device manufacturing method according to claim 1,

wherein the lighting-up includes lighting-up a whole screen of the target display device.

13. The display device manufacturing method according to claim 1,

wherein the predetermined period is a period of time ranging between 0.5 hour to 1.5 hour.

14. The display device manufacturing method according to claim 8,

wherein one area of the two or more areas of the target display device is located at a corner region of the target display device.

15. The display device manufacturing method according to claim 1, further comprising:

determining whether or not all of the pixels emitted light during the predetermined period.

16. The display device manufacturing method according to claim 8,

wherein one area of the two or more areas of the target display device includes five separate regions of the display device.