LIQUID CRYSTAL DISPLAY DEVICE AND MANUFACTURING METHOD FOR SAME

• US 20100321283A1
• Filed: 06/16/2010
• Published: 12/23/2010
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Mizuno, Yasuhiro, Sakurai, Masato, Hayahara, Shinsuke, Tanno, Junji, Kimura, Yasukazu, Fujiyoshi, Jun
• Granted Patent: US 8,953,122 B2
• Time in Patent Office: Days
• US Class Current: 345/88
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: G02F 1/136222 Colour filters incorporated in the active matrix substrate
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136236 using a grey or half tone lithographic process
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate

Abstract

A liquid crystal display device with a higher aperture ratio is provided. According to one embodiment of the present invention, second color filters are formed so as to overlap with first color filters when adjacent color filters having different colors are formed on the TFT substrate side, so that the angle of the first tapers where said first color filters overlap and the angle of the second tapers where said second color filters overlap are set to 45° or more and 90° or less.

Claims

1. A liquid crystal display device, comprising a pair of substrates positioned so as to face each other and sandwich liquid crystal, wherein

gate signal lines made of a light blocking material which run in a first direction and are aligned in a second direction which crosses said first direction, and drain signal lines made of alight blocking material which run in said second direction and are aligned in said first direction, are formed on the surface of one of the two substrates, on the liquid crystal side, and

thin film transistors which are turned on by a scanning signal through a gate signal line and pixel electrodes to which a video signal is supplied from a drain signal line through a thin film transistor when turned on are provided in pixel regions, pixel regions being defined as regions surrounded by two adjacent gate signal lines and two adjacent drain signal lines, characterized in that

each of said pixel regions is provided with at least a gate signal line, a drain signal line and a color filter formed in a layer above a thin film transistor,

overlapping regions between adjacent first color filters and second color filters are provided in regions in which said drain signal lines or said gate signal lines are formed as viewed from the top, and

the angle of the first taper of said first color filters formed in said overlapping regions is set to 45°

or more and 90°

or less relative to the surface of said drain signal lines or gate signal lines, the angle of the second taper of said second color filters formed in said overlapping regions is set to 45°

or more and 90°

or less relative to the surface of said first color filters, and the width of said signal lines is set to 1 μ

m or more and 4 μ

m or less.

2. The liquid crystal display device according to claim 1, characterized in that the film thickness of each color filter is set to 1 μ

m or more and 4 μ

m or less.

3. The liquid crystal display device according to claim 1, characterized in that the film thickness of each color filter is set to 1 μ

m or more and 4 μ

m or less, and the overlapping portions between said first color filters and said second color filters have a step of 1 μ

m or less.

4. The liquid crystal display device according to claim 1, characterized in that the end of the first taper of said first color filters overlaps with the second taper of said second color filters.

5. The liquid crystal display device according to claim 1, characterized in that the angle of the first taper of said first color filters formed in said overlapping regions is set to 45°

or more and 70°

or less relative to the surface of said drain signal lines or gate signal lines, and the angle of the second taper of said second color filters formed in said overlapping regions is set to 45°

or more and 70°

or less relative to the surface of said first color filters.

6. The liquid crystal display device according to claim 1, characterized in that the density of the pigment in said color filters is 10% or more and 60% or less.

7. The liquid crystal display device according to claim 1, characterized in that the density of the pigment in said second color filters is lower than the density of the pigment in said first color filters.

8. The liquid crystal display device according to claim 1, characterized in that the relative dielectric constant of said color filters is 3.0 or more and 7.0 or less.

9. The liquid crystal display device according to claim 1, characterized in that said color filters are formed in accordance with a selective etching method by means of photolithographic technology using an aligner or stepper.

10. A manufacturing method for a liquid crystal display device comprising:

a pair of substrates provided so as to face each other and sandwich liquid crystal, gate signal lines which run in a first direction and are aligned in a second direction which crosses said first direction, and drain signal lines which run said second direction and are aligned in said first direction;

thin film transistors driven by a scanning signal from a gate signal line; and

color filters formed so as to cover said gate signal lines, said drain signal lines and said thin film transistors, and pixel electrodes formed in a layer above these color filters, characterized by comprising the steps of;

forming said color filters with color overlapping portions where adjacent color filters overlap, and at the same time creating contact holes for electrically connecting said pixel electrodes to said thin film transistors; and

carrying out halftone exposure to light in the contact hole portions of said color filters, the color overlapping portions, or both, so that the angle of the taper in said color overlapping portion is smaller than the angle of the taper of said contact holes when said color filters are formed in accordance with photolithographic technology.

11. The manufacturing method for a liquid crystal display device according to claim 10, characterized in that the angle of the taper in said color overlapping portions in said color filters is 30°

or more and 75°

or less.

12. The manufacturing method for a liquid crystal display device according to claim 10, characterized in that the angle of the taper in said contact holes in said color filters is 45°

or more and 90°

or less.

13. The manufacturing method for a liquid crystal display device according to claim 10, characterized in that the color filters are formed so as too contain a pigment, and the density of the pigment is 10% or more and 60% or less.

14. The manufacturing method for a liquid crystal display device according to claim 10, characterized in that the amount of color overlap in said color overlapping portions in said color filter is 1 μ

m or more and 7 μ

m or less.

15. The manufacturing method for a liquid crystal display device according to claim 10, characterized in that the halftone exposure to light in said color overlapping portions in said color filters is carried out in an area 1 μ

m to 5 μ

m from the end of said color filters.

16. The manufacturing method for a liquid crystal display device according to claim 10, characterized in that the halftone exposure to light in said contact portions in said color filters is carried out in an area 1 μ

m to 5 μ

m from the edge of said contact portions.

17. A liquid crystal display device, comprising:

a pair of substrates provided so as to face each other and sandwich liquid crystal, gate signal lines which run in a first direction and are aligned in a second direction which crosses said first direction, and drain signal lines which run said second direction and are aligned in said first direction;

thin film transistors driven by a scanning signal from a gate signal line; and

color filters formed so as to cover said gate signal lines, said drain signal lines and said thin film transistors, and pixel electrodes formed in a layer above these color filters, characterized in that

said color filters have color overlapping portions where adjacent color filters overlap and contact holes for electrically connecting said pixel electrodes to said thin film transistors; and

the angle of the taper in said color overlapping portion is smaller than the angle of the taper of said contact holes.

18. The liquid crystal display device according to claim 17, characterized in that the angle of the taper in said color overlapping portions in said color filters is 30°

or more and 75°

or less.

19. The liquid crystal display device according to claim 17, characterized in that the angle of the taper in said contact holes in said color filters is 45°

or more and 90°

or less.

20. The liquid crystal display device according to claim 17, characterized in that the color filters are formed so as too contain a pigment, and the density of the pigment is 10% or more and 60% or less.

21. The liquid crystal display device according to claim 17, characterized in that the amount of color overlap in said color overlapping portions in said color filter is 1 μ

m or more and 7 μ

m or less.