Method for producing an LCD by pressing the substrates

• US 5,629,787 A
• Filed: 05/23/1995
• Issued: 05/13/1997
• Est. Priority Date: 05/25/1992
• Status: Expired due to Fees

• Current Assignee: Sharp Electronics Corporation (Hon Hai Precision Industry Co., Ltd.), Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Tsubota, Koujiro, Yoshimura, Yohji, Kamei, Hirokazu, Takafuji, Yutaka, Kubo, Masumi, Fujioka, Kazuyoshi, Ohgami, Hiroyuki, Nomura, Katsumi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Malinowski, Walter J.
• Application Number:
  US08/447,952
• Time in Patent Office: 721 Days
• Field of Search: 359/62, 359/80, 359/81, 359/82
• US Class Current: 349/153
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/1341 Filling or closing of cells

Abstract

A liquid crystal display device including a first substrate, a second substrate, and a sealing member for bonding the first and the second substrates, wherein a spacer for determining a thickness of a gap between the first and the second substrates is included only in the sealing member and wherein d<D where D is the thickness of the gap and d is the thickness of the sealing member. The gap is filled with a liquid crystal. A method for producing a liquid crystal display including the steps of pressing a liquid crystal panel including a first substrate and a second substrate interposing a sealing member which contains a spacer mixed therein, the spacer determining a thickness of a gap between the first and the second substrates, in a state where an elastic sheet having a cutout corresponding to the liquid crystal panel is provided a surface of one of the first and the second substrates, the surface being out of contact with the sealing member; curling the sealing member; and injecting a liquid crystal into the gap.

Claims

1. A method for producing a liquid crystal display, the liquid crystal display including a first substrate, a second Substrate opposing the first substrate and a liquid crystal interposed therebetween, the method comprising the steps of:

pressing the first substrate and the second substrate interposing a sealing member which contains a spacer mixed therein and which is provided to surround a display region for conducting a display, while an elastic sheet having a cutout corresponding to the display region is disposed on one surface of the first substrate and the second substrate thereby forming a gap between the first and the second substrates in the display region larger than that in a region where the sealing member is provided, the surface on which the elastic sheet is disposed being out of contact with the sealing member;

curing the sealing member; and

injecting the liquid crystal into the gap.

2. A method for producing a liquid crystal display device according to claim 1, wherein the elastic sheet has a surface roughness on both surfaces thereof, waves of the surface roughness having a height of 5 μ

m to 30 μ

m and a periodicity of 200 μ

m to 800 μ

m.

3. A method for producing a liquid crystal display device according to claim 1, wherein the cutout has a shape which fulfills the following formula:

space="preserve" listing-type="equation">Y/3≦

X≦

Y/2

where X is the distance between an end of the cutout of the elastic sheet and an outer perimeter of the region where the sealing member is provided after the first and the second substrates are pressed, and Y is the width of the region where the sealing member is provided after the first and the second substrates are pressed.

4. A method for producing a liquid crystal display device according to claim 1, wherein the gap between the first and the second substrates gradually increases as the distance from the region where the sealing member is located increases.

5. A method for producing a liquid crystal display device including two substrates combined together through a sealing member containing a spacer mixed therein, the spacer determining a thickness of a gap between the substrates, the gap including no spacer in a display area at a central portion thereof, the method comprising the steps of:

entirely pressing at least one of the substrates by a complex pressing medium including a buffering member and a pressing member; and

curing the sealing member and thus adhering the substrates to each other in a state of being pressed wherein said complex pressing medium includes a groove formed at least at one surface thereof for eliminating air from between the pressing medium and one of the two substrates in contact with said complex pressing medium.

6. A method for producing e liquid crystal display device according to claim 5, wherein the buffering member is formed of a material selected from the group consisting of an elastic material and a solid, the elastic material including a substance selected from the group consisting of a gas and a solid, the solid being selected from the group consisting of alkali halide crystal particle and pyroferrite.

7. A method for producing a liquid crystal display device according to claim 5, wherein at least one of the buffering member and the pressing member has a flatness which is equal or more than that of the two substrates and a resiliency against deflection which is higher than that of the two substrates, and wherein the complex pressing medium is arranged so that a flat surface thereof is in contact with at least one of the two substrates.

8. A method for producing a liquid crystal display device according to claim 5, further comprising the step of heating the sealing member to a temperature higher than the temperature at which the sealing member is transited to glass, after the sealing member is cured.

9. A method for producing a liquid crystal display device according to claim 5, wherein the sealing member contains a polymerization initiator which is activated by ultraviolet radiation and a material which is thermally activated.

10. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device, comprising the steps of:

applying the sealing member on a first substrate so as to define a display area substantially enclosed by the sealing member, the display area including no spacer;

attaching a second substrate on the first substrate to form a panel;

pressing the panel so that the spacer determines a gap between the first and second substrates, under a condition that a pressure applied on the panel in a region other than a portion corresponding to the display area is substantially larger than that on the panel in the portion corresponding to the display area; and

curing the sealing member so as to produce the cell in which d D, where D is a distance between the first and second substrates in the display area, and d is a distance between the first and second substrates spaced by the spacer.

11. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device according to claim 10, wherein D≦

1.2×

d.

12. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device according to claim 10, wherein in the applying step, the sealing member is applied so that the display area has at least one side having a length of 25 mm or more.

13. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device according to claim 10, wherein in the applying step, the sealing member is applied to define a plurality of the display areas so that the panel includes the plurality of the cells.

14. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device according to claim 10, wherein the pressing step comprises the steps of:

providing an elastic sheet having a cutout corresponding to the display area onto a surface of the panel, and

applying a pressure on the panel through the elastic sheet.

15. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device according to claim 14, wherein the elastic sheet is placed so that an edge of the cutout is positioned within a width of the applied sealing member in the providing step.

16. A method for producing a cell including a pair of substrates assembled with a sealing member used for a liquid crystal display device according to claim 14, wherein both sides of the elastic sheet have a roughness with a height difference of 5 μ

m to 30 μ

m with a period of 200 μ

m to 800 μ

m.