Liquid crystal process defect inspection apparatus and inspection method

• US 20050041243A1
• Filed: 04/22/2002
• Published: 02/24/2005
• Est. Priority Date: 10/25/2001
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choo, Dae-Ho, Won, Min-Young, Jeon, Beak-Keun, Nam, Hyoo-Hak
• Granted Patent: US 7,113,278 B2
• Time in Patent Office: Days
• US Class Current: 356/239.100
• CPC Class Codes: G01N 21/23 Bi-refringence
• CPC Class Codes: G01N 21/896 Optical defects in or on transparent materials, e.g. distortion, surface flaws in conveyed flat sheet or rod for other objects G01N21/958

Abstract

The glass substrate test apparatus of the liquid crystal cell process comprises a laser unit for generating a laser beam, a beam slitter and parallel beam slitter for slitting the laser beam emitted from the laser unit so as to have an elongated cross section and parallelizing the slit laser beam, a photo detector for detecting an intensity of double refraction of the slit laser beam transmitted over the whole glass substrate, a phase defector for measuring the laser double refraction detected by the photo detector and comparing the measured double refraction with a standard laser double refraction, and a polarizer arranged between the laser unit and the beam slitter or between the beam slitter and the parallel beam slitter for polarizing the laser beam to a parallel ray.

Claims

1. A glass substrate test apparatus in an LCD-manufacturing line comprising:

a laser unit generating and emitting a laser beam;

a beam slitter for slitting the laser beam from the laser unit and a parallel beam slitter for parallelizing the laser beam from the beam slitter;

a photo detector for measuring double refraction intensity of a whole surface of a glass substrate using a slit laser beam from the parallel beam slitter;

a phase detector for comparing a laser double refraction measured by the photo detector with a standard laser double refraction; and

a polarizer arranged between the laser unit and the beam slitter or between the beam slitter and the parallel beam slitter for polarizing the laser beam.

2. The glass, substrate test apparatus of claim 1, wherein the beam slitter and the parallel beam slitter are formed in one of 4 configurations, which are convex-convex lens, convex-concave lens, concave-convex lens, and concave-concave lens configurations.

3. The glass substrate test apparatus of claim 1, wherein a plurality of beam slitters and parallel beam slitters are used for covering a width of the whole glass substrate, and the laser beams and the parallel laser beam slitters are arranged such that the laser beams are alternately arranged In two rows relative to a progression direction of the glass substrate having a distance between the slit laser beams in the same row.

4. The glass substrate test apparatus of claim 3, wherein the slit laser beams are arranged such that the slit laser beams are overlapped in two other rows over a predetermined length.

5. The glass substrate test apparatus of claim 1, wherein a plurality of beam slitters and parallel beam slitters are used for covering a width of the whole glass substrate, and the laser beam slitters and the parallel laser beam slitters are arranged such that the laser beams are arranged in a single row.

6. The glass substrate test apparatus of claim 5, wherein the slit laser beams are arranged such that the slit laser beams are overlapped over a predetermined length.

7. The glass substrate test apparatus of claim 1, wherein the laser unit, the beam slitter, the parallel beam slitter, and the polarizer are configured in an integral optical system such that the plurality of optical systems are used in consideration of a size of the glass substrate and a length of a slit laser beam.

8. The glass substrate test apparatus of claim 1, wherein the photo detector is arranged as a single or an array type identical with the glass substrate for detecting the laser double refraction per unit area.

9. The glass substrate test apparatus of claim 1, further comprising a beam expander arranged between the laser unit and the beam slitter for expanding the laser beam emitted from the laser unit.

10. The glass substrate test apparatus of claim 1, further comprising a sprayer arranged between the parallel beam slitter and the glass substrate for magnifying the laser double refraction by spraying water, alcohol, or an organic compound on the glass substrate.

11. The glass substrate test apparatus of claim 1, further comprising a polarization elastic modulator arranged between the glass substrate and the photo detector for forming a required wavelength.

12. The glass substrate test apparatus of claim 1, wherein the laser unit is arranged above the glass substrate and the photo detector is arranged below the glass substrate for detecting double is refraction of the laser transmitted over the glass substrate.

13. The glass substrate test apparatus of claim 1, further comprising a reflection plate arranged below the glass substrate for reflecting the laser transmitted through the glass substrate wherein the laser unit and the photo detector are arranged above the glass substrate for detecting the double refractions of the laser beam reflected through the glass substrate by the reflection plate.

14. A glass substrate test method in a liquid crystal cell fabricating process comprising:

setting standard laser double refraction data to a inspection standard;

detecting laser double refraction by projecting a laser beam over a whole glass substrate;

comparing the detected laser double refraction with the standard laser double refraction;

determining whether or not a double refraction difference is within a utilization range of the glass substrate; and

judging that the glass substrate has no defects if the double refraction difference is within the utilization range of the glass substrate, or judging that the glass substrate has defects if the double refraction difference is outside the utilization range of the glass substrate and then reworking the glass substrate.

15. The glass substrate test method of claim 14, wherein while detecting the laser double refraction, the glass substrate lo be tested moves at a speed of a liquid crystal cell process line below a inspection laser beam.

16. The glass substrate test method of claim 14, wherein while detecting the laser double refraction, the glass substrate to be tested is positioned below an inspection laser beam without moving.