Method for dividing substrates of liquid crystal displays using repeated measurements

• US 5,278,685 A
• Filed: 10/27/1992
• Issued: 01/11/1994
• Est. Priority Date: 10/29/1991
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Takanashi, Hiroshi, Misono, Kenji, Iwamoto, Makoto, Isohata, Kyouhei, Fukuchi, Shunsei
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/967,263
• Time in Patent Office: 441 Days
• Field of Search: 359/62, 359/82, 359/83, 225/2, 225/96.5, 29/413, 29/592.1, 83/863, 83/876, 83/360, 83/364, 83/879, 83/881, 83/884, 356/355, 445/24, 437/226, 264/138, 264/157
• US Class Current: 349/187
• CPC Class Codes: B28D 1/10 with provision for measuring
• CPC Class Codes: B28D 5/0058 Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material B28D5/0005, B28D5/024 take precedence
• CPC Class Codes: B28D 5/022 by cutting with discs or wheels
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133351 Manufacturing of individual cells out of a plurality of cells, e.g. by dicing

Abstract

First and second transparent hard plastic substrates are placed one over the other to form therebetween a gap into which a liquid crystal is to be sealed in. The first and second substrates are mounted on the reference plane of a stage. The distance between the first substrate and the reference plane is measured in a non-contact manner at a plurality of measuring points on a predetermined dividing line. Based on the distances measured, a slit is formed on the first substrate by cutting the first substrate along the dividing line while leaving a portion of a predetermined thickness uncut. The first substrate is then broken along the slit. With this arrangement, it is possible to cut the substrates while leaving a portion of an appropriate thickness uncut irrespective of unevenness of the thickness or waviness of the first substrate. Moreover, since the surfaces of the cut sections of the substrates do no crack and since the portions of the substrates to be broken have a reduced thickness, the divided sections have smoother surfaces.

Claims

1. A method for dividing substrates constituting liquid crystal display elements compromising the steps of:

(a) placing a pair of transparent substrates one over the other so as to form therebetween a gap into which a liquid crystal is to be sealed in;

(b) mounting said substrates on a reference plane of a state so as to make a surface of said substrates come into contact with said reference plane;

(c) measuring a distance between said reference plane and one substrate as a first substrate in a non-contact manner at a plurality of measuring points on a dividing line along which said first substrate is cut;

(d) making a slit on said first substrate by cutting said first substrate along said dividing line, said first substrate being cut based on the measured distances which vary due to the lack of uniform thickness informing said substrates so as to keep a portion of said first substrate with a substantially uniform predetermined thickness uncut; and

(e) diving said first substrate by breaking it along said dividing line.

2. The method for dividing substrates constituting liquid crystal display elements according to claim 1, wherein said substrates are made of a synthetic resin.

3. The method for dividing substrates constituting liquid crystal display elements according to claim 1, wherein said substrates are made of an acrylic resin.

4. The method for dividing substrates constituting liquid crystal display elements according to claim 1, wherein said substrates are made of an epoxy resin.

5. The method for dividing substrates constituting liquid crystal display elements according to claim 1, wherein said first substrate is cut with a rotating dicing blade.

6. The method for dividing substrates constituting liquid crystal display elements according to claim 5, wherein said first substrate is cut along the dividing line by changing a position of the first substrate with respect to the dicing blade while changing a position of said dicing blade with respect to said reference plane based on the distances measured, the position of said first substrate with respect to said dicing blade being changed by moving the stage.

7. The method for dividing substrates constituting liquid crystal display elements according to claim 1, wherein the distance between said first substrate and said reference plane is measured optically by using an objective lens whose position is adjustable with respect to said reference plane and detecting a difference in the position of said objective lens when it is focused on said reference plane and that of said objective lens when it is focused on a surface of said first substrate facing said reference plane.

8. The method for dividing substrates constituting liquid crystal display elements according to claim 1, wherein the distance between said first substrate and said reference plane is measured optically by using laser light projected toward said reference plane through said substrates and detecting a phase difference between reflected light from said reference plane and reflected light from a surface of said first substrate facing said reference plane.

9. A method for dividing substrates constituting liquid crystal display elements comprising the steps of:

(a) placing first transparent substrate and a second transparent substrate one over the other so as to form therebetween a predetermined gap into which a liquid crystal is to be sealed in, said first substrate having a transparent electrodes on its surface for causing the liquid crystal to have an electric field;

(b) mounting said substrates on a reference plane of a stage so as to make said first substrate comes into contact with said reference plane;

(c) measuring a distance between said reference plane and said second substrate in a non-contact manner at a plurality of measuring points on a dividing line;

(d) making a slit on said second substrate by cutting said second substrate along said dividing line, said second substrate being cut based on the measured distances which can vary due to the lack of uniform thickness in forming said substrate so as to keep a portion of said second substrate with a substantially uniform predetermined thickness uncut; and

(e) breaking a portion of said second substrate off along said dividing line so as to expose said transparent electrodes on said first substrate.

10. The method for dividing substrates constituting liquid crystal display elements according to claim 9, wherein said substrates are made of an acrylic resin.

11. The method for dividing substrates constituting liquid crystal display elements according to claim 9, wherein said second substrate is cut with a rotating dicing blade.

12. The method for dividing substrates constituting liquid crystal display elements according to claim 9, wherein said second substrate is cut while changing a position of said dicing blade with respect to said reference plane based on the distances measured.

13. The method for dividing substrates constituting liquid crystal display elements according to claim 9, wherein the distance between said second substrate and said reference plane is measured optically by using an objective lens whose position is adjustable with respect to said reference plane and detecting a difference in the position of said objective lens when it is focused on said reference plane and that of said objective lens when it is focused on a surface of said second substrate facing said reference plane.

14. The method for dividing substrates constituting liquid crystal display elements according to claim 9, wherein the distance between said second substrate and said reference plane is measured optically by using laser light projected toward said reference plane through said substrates and detecting a phase difference between reflected light from said reference plane and reflected light from a surface of said second substrate facing said reference plane.

15. A method for dividing substrates constituting liquid crystal display elements comprising the steps of:

(a) placing a first transparent substrate and a second transparent substrate one over the other so as to form therebetween a predetermined gap into which a liquid crystal is to be sealed in, said first substrate having on its inner surface a transparent layer formed along a predetermined dividing line;

(b) mounting said substrates on a reference plane of a stage so as to locate said transparent layer between said first substrate and said reference plane;

(c) measuring a distance between said reference plane and said first substrate at a plurality of measuring points on said dividing line by projecting laser light onto said reference plane through said first layer and said transparent layer and detecting a phase difference between reflected light from said reference plane and reflected light from a phase boundary between said first substrate and said transparent layer;

(d) making a slit on said first substrate by cutting said first substrate toward said reference plane based on the measured distances which vary due to the lack of uniform thickness in forming said substrates so as to keep a portion of said first substrate with a substantially uniform predetermined thickness uncut; and

(e) breaking said first substrate along the slit.

16. The method for dividing substrates constituting liquid crystal display elements according to claim 15, wherein said substrates are made of a synthetic resin.

17. The method for dividing substrates constituting liquid crystal display elements according to claim 15, wherein said substrates are made of an acrylic resin.

18. The method for dividing substrates constituting liquid crystal display elements according to claim 15, wherein said substrates are made of an epoxy resin.

19. The method for dividing substrates constituting liquid crystal display elements according to claim 15, wherein said first substrate is cut with a rotating dicing blade.

20. The method for dividing substrates constituting liquid crystal display elements according to claim 19, wherein said first substrate is cut while changing a position of said dicing blade with respect to said reference plane by moving said stage.

21. The method for dividing substrates constituting liquid crystal display elements according to claim 15, wherein said transparent layer is a transparent electrode.

22. The method for dividing substrates constituting liquid crystal display elements according to claim 15, wherein a sealing layer is formed between said first and second substrates along said dividing line.

23. A method for dividing substrates constituting liquid crystal display elements comprising the steps of:

(a) placing a first transparent substrate and a second transparent substrate one over the other so as to form therebetween a gap into which a liquid crystal is to be sealed in;

(b) mounting said first and second substrates on a reference plane of a stage so as to make said first substrate come into contact with said reference plane;

(c) measuring a distance between said reference plane and said second substrate in a non-contact manner at a plurality of measuring points on a dividing line for cutting said second substrate;

(d) making a slit on said second substrate with cutting means by cutting said second substrate toward said reference plane based on the measured distances which vary due to the lack of uniform thickness in forming said substrates so as to keep a portion of said second substrate with a substantially uniform predetermined thickness uncut;

(e) removing a burr produced on each side of an opening of said slit with burr removing means, said burr removing means follows a movement of the cutting means;

(f) breaking said second substrate along said slit;

(g) removing said first and second substrates from said stage;

(h) mounting said first and second substrates on said reference plane of said stage so as to make said second substrate come into contact with said reference plane;

(i) measuring a distance between said reference plane and said first substrate in a non-contact manner at a plurality of measuring points on a dividing line for cutting said first substrate;

(j) making a slit on said first substrate by cutting said first substrate toward said reference plane based on the measured distances which vary due to the lack of uniform thickness in forming said substrate so as to keep a portion of said first substrate with a substantially uniform predetermined thickness uncut; and

(k) breaking said first substrate along said slit.

24. The method for dividing substrates constituting liquid crystal display elements according to claim 23, wherein said burr removing means is a rotating abrasive wheel.

25. The method for dividing substrates constituting liquid crystal display elements according to claim 23, wherein a thickness of said rotating abrasive wheel along its rotating axis becomes smaller from the center toward the edge in a radial direction.

26. The method for dividing substrates constituting liquid crystal display elements according to claim 23, wherein a transparent electrode is formed on each of said substrates and said substrates are placed one over the other so as to sandwich said transparent electrodes.

27. The method for dividing substrates constituting liquid crystal display elements according to claim 23, wherein said cutting means is a dicing blade.