Apparatus and method for inspecting a liquid crystal display panel

• US 20050231229A1
• Filed: 04/15/2005
• Published: 10/20/2005
• Est. Priority Date: 04/19/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Chung, Han Rok, Byun, Sung Nam
• Granted Patent: US 7,202,695 B2
• Time in Patent Office: Days
• US Class Current: 324/760.10
• 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

An apparatus and method for inspecting a liquid crystal display device is provided. The apparatus includes: a camera photographing a front surface of a liquid crystal panel; a back light irradiating light to the liquid crystal panel; a diffuser sheet diffusing the light generated from the back light; a prism sheet converting the diffused light so as to be perpendicularly incident to a rear surface of the liquid crystal panel; a probe unit applying an inspection signal to the liquid crystal panel; and a frequency converter converting a frequency of the light generated from the back light. The apparatus for inspecting the liquid crystal display device according to the invention detects bad sub-pixels, impossible to detect with the naked-eye, improving the quality of the liquid crystal display device.

Claims

1. An apparatus for inspecting a liquid crystal display device comprising:

a probe unit applying an inspection signal to a liquid crystal panel;

a light source irradiating light to the liquid crystal panel;

an optical sheet, stacked between the light source and the liquid crystal panel, diffusing the light generated from the light source and changing an exit angle of the diffused light; and

an optical system receiving the inspection signal and data about picture implemented on the liquid crystal panel by irradiating the light.

2. The apparatus according to claim 1, wherein the optical sheet includes a diffuser sheet diffusing the light generated from the light and a prism sheet changing the exit angle of the light diffused from the diffuser sheet.

3. The apparatus according to claim 1, further comprising:

frequency adjusting means for adjusting a frequency of the light generated from the light source.

4. The apparatus according to claim 3, wherein the frequency adjusting means adjusts the frequency of the light generated from the light source to be substantially identical to a photographing frequency of the optical system.

5. The apparatus according to claim 1, wherein the optical system includes at least one of a line charge coupled device camera scanning the liquid crystal panel line by line to gain data and an area charge coupled device camera scanning the liquid crystal panel for area by area to gain data.

6. The apparatus according to claim 1, wherein the probe unit includes:

a probe base;

a printed circuit board(PCB) base installed at an edge of the probe base;

a tape carrier package block to which a driving circuit is connected;

a probe block, connected to the liquid crystal panel, supplying the driving inspection signal from the tape carrier package to the liquid crystal panel; and

a manupulator for reducing collision and friction forces generated upon inserting the liquid crystal panel into the probe unit.

7. The apparatus according to claim 1, further comprising:

a data processor for processing data gained from the optical system; and

a picture display device for displaying the processed data on a picture.

8. The apparatus according to claim 7, wherein the data processor displays detected defects in the liquid crystal panel on the picture display device.

9. A method for inspecting a liquid crystal display panel, comprising:

uniformly irradiating a rear surface of the liquid crystal display panel;

supplying the liquid crystal display panel with driving signals;

scanning the liquid crystal display panel with an optical device;

processing the scanning data obtained by the optical device to determine defects in the liquid crystal display panel; and

displaying the detected defects on a display device.

10. The method of claim 9, where uniformly irradiating the liquid crystal display panel comprises:

generating light from a light source;

passing the light through a diffuser sheet; and

passing the diffused light through a prism sheet such that the light exiting the prism sheet is perpendicularly incident to the rear surface of the liquid crystal display panel.

11. The method of claim 10, further comprising:

adjusting a frequency of the light generated from the light source to be substantially equal to a photographic frequency of the optical device.

12. The method of claim 9, wherein the optical device is a charge coupled device camera.

13. The method of claim 9, wherein the optical device scans the liquid crystal display panel line by line.

14. The method of claim 9, wherein the optical device scans predetermined areas of the liquid crystal display panel.