Method for producing an LCD having no spacers in the display area in which heating alleviates cell distortion or greater pressure is applied to the seal region

• US 5,677,749 A
• Filed: 05/23/1995
• Issued: 10/14/1997
• Est. Priority Date: 05/25/1992
• 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: Takafuji, Yutaka, Kubo, Masumi, Fujioka, Kazuyoshi, Ohgami, Hiroyuki, Nomura, Katsumi, Tsubota, Koujiro, Yoshimura, Yohji, Kamei, Hirokazu
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Malinowski, Walter J.
• Application Number:
  US08/445,531
• Time in Patent Office: 875 Days
• Field of Search: 359/80, 359/81, 359/82, 349/153, 349/155, 349/158, 349/160, 349/187, 349/189, 349/190
• US Class Current: 349/160
• 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; curing the sealing member; and injecting a liquid crystal into the gap.

Claims

1. A method for producing a liquid crystal display device including a pair of substrates combined together with a sealing member and a liquid crystal interposed between the substrates, the method comprising the steps of:

applying a sealing member on a first substrate of the pair so as to define a display area substantially enclosed by the sealing member, the sealing member, the sealing member containing a spacer mixed therein, the spacer determining a gap between the substrates; and

assembling the first and second substrates to produce a liquid crystal cell, in a state where the gap of the liquid crystal cell is maintained by the spacer in the sealing member, with no spacer existing in the display area of the liquid crystal cell,

wherein the assembling step further includes the steps of,

attaching the 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 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 form a cell;

heating the cell so as to alleviate a distortion of the panel; and

injecting the liquid crystal into the gap of the cell to produce the liquid crystal cell, and

wherein the display area has a one-inch or more diagonal dimension.

2. A method for producing a liquid crystal display device including a pair of substrates combined together with a sealing member and a liquid crystal interposed between the substrates, the method comprising the steps of:

applying a sealing member on a first substrate of the pair so as to define a display area substantially enclosed by the sealing member, the sealing member containing a spacer mixed therein, the spacer determining a gap between the substrates; and

assembling the first and second substrates to produce a liquid crystal cell, in a state where the gap of the liquid crystal cell is maintained by the spacer in the sealing member, with no spacer existing in the display area of the liquid crystal cell,

wherein the assembling step further includes the steps of,

attaching the 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 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 form a cell; and

injecting the liquid crystal into the gap of the cell to produce the liquid crystal cell,

wherein the display area has a one-inch or more diagonal dimension, and

wherein the cell satisfies a condition of d<

D before injecting the liquid crystal, where D is a distance between the first and second substrates in the display area of the cell and, d is a distance between the first and second substrates spaced by the spacer.

3. A method for producing a liquid crystal display device according to claim 2, wherein D≦

1.2 X d.

4. A method for producing a liquid crystal display device including a pair of substrates combined together with a sealing member and a liquid crystal interposed between the substrates, the method comprising the steps of:

applying a sealing member on a first substrate of the pair so as to define a display area substantially enclosed by the sealing member, the sealing member containing a spacer mixed therein, the spacer determining a gap between the substrates; and

assembling the first and second substrates to produce a liquid crystal cell, in a state where the gap of the liquid crystal cell is maintained by the spacer in the sealing member, with no spacer existing in the display area of the liquid crystal cell,

wherein the assembling step further includes the steps of,

attaching the 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 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 form a cell; and

injecting the liquid crystal into the gap of the cell to produce the liquid crystal cell,

wherein the display area has a one-inch or more diagonal dimension, and

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.

5. A method for producing a liquid crystal display device according to claim 4, 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.

6. A method for producing a liquid crystal display device according to claim 5, 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.

7. A method for producing a liquid crystal display device including two substrates and a liquid crystal material interposed therebetween, at least one of the two substrates including active elements for selectively controlling electrooptic characteristics of the liquid crystal material, the method comprising the steps of:

applying a sealing member on at least one of the two substrates in patterns, the patterns including a first pattern along which the active elements are arranged and a second pattern for promoting uniform distribution of a pressing force;

assembling the two substrates such that the sealing member is disposed between the two substrates without interposing spacers therebetween so as to form a cell;

radiating ultraviolet light onto the entire surface of the cell while pressing the two substrates to cure the sealing member; and

heating the cell to alleviate the distortion of the cell.

8. A method for producing a liquid crystal display device according to claim 7, wherein the patterns of the sealing member further include third patterns for partially bonding the two substrates, and the method further comprises the step of partially bonding the two substrates by radiating ultraviolet light only on the third patterns of the cell, prior to pressing the two substrates.

9. A method for producing a liquid crystal display device according to claim 7, wherein the two substrates are pressed by a pressing machine including at least one buffer layer and an ultraviolet radiation apparatus, while the cell is sandwiched between the at least one buffer layer and the ultraviolet radiation apparatus.

10. A method for producing a liquid crystal display device according to claim 7, wherein the sealing member transforms into glass at a temperature, and wherein the cell is heated at a temperature higher than the temperature at which the sealing member transforms into glass.

11. A method for producing a liquid crystal display device according to claim 7, further comprising the step of injecting the liquid crystal material into a gap of the cell.

12. A method for producing a liquid crystal display device according to claim 7, wherein at least one of the two substrates includes a transparent electrode formed thereon.

13. A method for producing a liquid crystal display device according to claim 7, wherein a pressing force applied to the two substrates is selected depending on a viscosity of the sealing member and a relationship between the thickness of the cell and the pressing force per unit area.

14. A method for producing a liquid crystal display device according to claim 7, wherein the sealing member contains a polymerization initiator which is activated by ultraviolet radiation and a material which is thermally activated.