Method and system for testing a display panel assembly

• US 7,860,296 B2
• Filed: 11/10/2005
• Issued: 12/28/2010
• Est. Priority Date: 11/11/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yang, Kyoung-Ho, Kwon, Sang-Hyuk, Park, Soon-Jae
• Primary Examiner(s): Bali; Vikkram
• Assistant Examiner(s): ENTEZARI, MICHELLE M
• Application Number:
  US11/272,479
• Publication Number:
  US 20060120588A1
• Time in Patent Office: 1,874 Days
• Field of Search: None
• US Class Current: 382/141
• 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

Abstract

A test system includes a rotatable turntable, a loading section, a first image pickup section, a second image pickup section, a system control section and an unloading section. The loading section loads a display panel assembly onto the stage. The loading section recognizes a unique number of the display panel assembly. The first image pickup section obtains an active area image data from an active area image. A valid first active area defect is detected using an active area image data obtained from an active area image displayed on the display panel assembly. An inactive area defect is detected based on an inactive area image data and a reference inactive area image data.

Claims

1. A test system comprising:

a rotatable turntable including a plurality of stages;

a loading section loading a display panel assembly onto the stages, the loading section recognizing a unique number of the display panel assembly;

a first image pickup section picking up first and second active area image displayed on the display panel assembly, the first image pickup section obtaining first and second active area image data from the first and second active area images;

a second image pickup section picking up an inactive area image displayed on the display panel assembly, the second image pickup section obtaining an inactive area image data from the inactive area image;

a system control section detecting a valid first active area defect by comparing the first and second active area image data with each other, the system control section detecting an inactive area defect by comparing the inactive area image data with a reference inactive area image data; and

an unloading section unloading the display panel assembly from the stage.

2. The test system of claim 1, further comprising:

a loading cassette receiving the display panel assemblies to be loaded onto the stage; and

an unloading cassette receiving the display panel assemblies unloaded from the stage.

3. The test system of claim 1, wherein the first image pickup section comprises:

a first camera picking up the first and second active area images displayed on the display panel assembly; and

a first signal processing section converting a signal of the first and second active area images into the first and second active area image data.

4. The test system of claim 1, wherein the second image pickup section comprises:

a second camera picking up the inactive area image displayed on the display panel assembly; and

a second signal processing section converting a signal of the inactive area image signal into the inactive area image data.

5. The test system of claim 1, wherein each of the stages comprises:

a backlight portion providing a light to a first side of the display panel assembly;

a support member disposed over the backlight portion, the support member supporting the display panel assembly;

a front light portion providing a light to a second side of the display panel assembly; and

a signal generating portion applying an electrical signal to the display panel assembly.

6. The test system of claim 5, wherein the system control section controls the stage to at least one of electrically drive the display panel assembly or optically drive the display panel assembly.

7. The test system of claim 1, wherein the system control section comprises:

an active area defect inspecting section examining a display quality;

an inactive area defect inspecting section examining an appearance of the display panel assembly; and

a controller controlling the system control section, the active area defect inspecting section and the inactive area defect inspecting section.

8. The test system of claim 7, wherein the active area defect inspecting section comprises:

an active area determining section determining an X-axis projection and a Y-axis projection of the first active area image data to determine an active area of the display panel assembly;

a second active area defect deleting section deleting a second active area defect from active area defects of the first active area image data; and

a valid first defect detecting section detecting a valid first defect of the first active area image data after the second defect is deleted from the first active area image data.

9. The test system of claim 8, wherein when a size of the active area determined by the active area determining section is different from a size of an actual active area of the display panel assembly by a predetermined value, the controller stops operations of the active area defect inspecting section and the inactive area defect inspecting section.

10. The test system of claim 8, wherein when the valid defect is detected from the first active area image data after the second defect is deleted from the first active area image data, the controller stops an operation of the inactive area defect inspection section.

11. The test system of claim 7, wherein the inactive area defect inspecting section comprises:

a reference data storing section storing the reference inactive area image data obtained from a reference display panel assembly being substantially free of the inactive area defect; and

an inactive area defect detecting section comparing the reference inactive area image data with the inactive area image data to detect the inactive area defect.

12. The test system of claim 8, wherein the active area determining section determines the active area using the first active area image data obtained from the first active area image generated using the backlight portion in a state free of an electrical field.

13. The test system of claim 8, wherein the second defect deleting section deletes the second defect based on a difference between the first active area image data and the second active area image data,

wherein the first active area image data is obtained from the first active area image generated using the backlight portion in a state of an electrical field, and

wherein the second active area image data is obtained from the second active area image generated using the front light portion in a state substantially free of the electrical field.

14. The test system of claim 8, wherein the valid first active area defect detecting section determines the valid first active area defect using a pixel singularity measurement method, a binary method and a blob analysis method,

wherein the pixel singularity measurement method determines a singularity of a standard pixel using differences in a gray level between the standard pixel and neighboring pixels that neighbor with the standard pixel,

wherein the binary method converts the singularity into binary digits of “

1”

or “

0”

, and

wherein the blob analysis method manages pixels having an identical binary digit as a group to detect the valid first active area defect.

15. The test system of claim 14, wherein the singularity S(x,y) is determined as

S(x,y)=Max[Min(G(x,y)−

G(x−

kn,y),G(x,y)−

G(x+kn,y)),Min(G(x,y)−

G(x,y−

kn),G(x,y)−

G(x,y+kn))],

wherein G(x,y) is a gray level of a pixel (x,y) and “

k” and

“

n”

are natural numbers.

16. The test system of claim 11, wherein the inactive area image data is obtained by the inactive area image generated using the backlight portion in a state substantially free of an electrical field.

17. A method of testing a display panel assembly comprising:

recognizing a unique number of the display panel assembly loaded onto a stage positioned on a turntable;

detecting a valid first active area defect by comparing first and second active area image data obtained from first and second active area image displayed on the display panel assembly;

detecting an inactive area defect by comparing inactive area image data with a reference inactive area image data, the inactive area image data being obtained from an inactive area image displayed on the display panel assembly; and

unloading the display panel assembly from the stage.

18. The method of claim 17, wherein detecting the valid first active area defect comprises:

detecting an active area of the display panel assembly using the first active area image data;

deleting a second active area defect from the first active area image data; and

detecting a valid first active area defect of the first active area image data after the second active area defect is deleted from the first active area image data.

19. The method of claim 17, wherein detecting the valid first active area defect comprises:

comparing the active area with an actual active area; and

when a size of the active area is different from a size of the actual active area by a predetermined value, stopping an active area defect inspecting process and an inactive area defect inspecting process.

20. The method of claim 18, further comprising when the valid first active area defect is detected, stopping an active area defect inspecting process and an inactive area defect inspecting process.

21. The method of claim 18, wherein detecting the active area comprises:

picking up the first active area image displayed on the display panel assembly using a backlight portion in a state substantially free of an electrical field;

converting the first image into the first active area image data;

determining an X-axis projection and a Y-axis projection using the first image data; and

determining the active area of the display panel assembly using the X-axis projection and the Y-axis projection.

22. The method of claim 21, wherein the step of deleting the second active area defect comprises:

when a test voltage is applied to the display panel assembly, picking up the first active area image displayed on the display panel assembly using a backlight portion;

converting the first active area image into the first active area image data;

when the test voltage is not applied to the display panel assembly, picking up the second active area image displayed on the display assembly using a front light portion;

converting the second active area image into the second active area image data; and

deleting the second active area defect by excluding the second active area image data from the first active area image data.

23. The method of claim 18, wherein the step of detecting the valid first active area defect comprises:

determining a singularity of a standard pixel using differences in a gray level between the standard pixel and neighboring pixels that neighbor with the standard pixel;

converting the singularity into binary digits of “

1”

or “

0”

; and

managing pixels having an identical binary digit as a group to detect the valid first active area defect.

24. The method of claim 17, wherein detecting the inactive area defect comprising:

picking up an inactive area image displayed on the display panel assembly using a backlight portion in a state substantially free of an electrical field;

converting a signal of the inactive area image into an inactive area image data; and

detecting the inactive area defect using a difference between the inactive area image data and the reference inactive area image data.