Transflective type LCD and method for manufacturing the same

• US 20050094067A1
• Filed: 12/13/2004
• Published: 05/05/2005
• Est. Priority Date: 08/06/2001
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NEC Corporation, NEC LCD Technologies Limited (Tianma Microelectronics Company Limited)
• Inventors: Ikeno, Hidenori, Kimura, Shigeru, Sakamoto, Michiaki, Morio, Kenji, Shinohara, Masaki, Ihida, Satoshi, Saeki, Kazurou
• Granted Patent: US 7,817,229 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133555 Transflectors
• 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

Abstract

In a transflective type LCD provided with a transparent region and a reflection region in each pixel, when an irregular film 11 is formed on an active matrix substrate 12 to form irregularities of a reflection electrode film 6, the irregular film 11 is specifically formed to almost the same film thickness in both the transparent region and the reflection region to provide substantially the same inter-substrate gap in these two regions so that they may have almost the same V-T characteristics and also the reflection electrode film 6 made of Al/Mo is formed so as to overlap with a transmission electrode film 5 made of ITO all around an outer periphery of the transmission electrode film 5 by a width of at least 2 μm, thus suppressing electric erosion from occurring between the ITO and Al substances at the edge of the transmission electrode film 5.

Claims

1-4. -4. (canceled)

5. A method for manufacturing a transflective type LCD, in said transflective type LCD having a first substrate provided thereon with a plurality of scanning lines and a plurality of signal lines which are substantially perpendicular to each other and a switching element arranged near each of intersections between said scanning lines and said signal lines, forming a reflection region having a reflection electrode film and a transmission region having a transparent electrode film in each pixel surrounded by said scanning lines and said signal lines and the liquid crystal is sandwiched at a gap between said first substrate and a second substrate which is arranged opposite to said first substrate, the method comprising:

when forming an organic film having irregularities thereon is formed below said reflection electrode film and said transparent electrode film to substantially the same film thickness,

forming a half-tone mask having a transmission portion, a shielding portion and a transflective portion in said pixel portion; and

forming said irregularities and a portion where said organic film is completely removed using said mask at a same time.

7. The method for manufacturing a transflective type LCD according to claim 5, wherein when forming a window portion for said transmission portion by removing a part of said reflection electrode film,

etching said reflection electrode film so as to overlap with said transmission electrode film by a predetermined width around an overall periphery of said window portion as viewed from a direction of a normal line of said substrate.

8. The method for manufacturing a transflective type LCD according to claim 7, wherein said etching is performed so that said width for overlapping is about 2 μ

m.

9. The method for manufacturing a transflective type LCD according to claim 5, wherein said reflection electrode film includes a two-layer construction comprising a barrier metal film and a reflection metal film, each of which is formed to a film thickness of about 100 nm or more.

10. The method for manufacturing a transflective type LCD according to claim 5, wherein said reflection electrode film includes a two-layer construction comprising a barrier metal film and a reflection metal film, each of which is formed to a film thickness of about 200 nm or more.

11. The method for manufacturing a transflective type LCD according to claim 9, wherein when at least one of said barrier metal film and said reflection metal film is formed, the metal film is once formed to a predetermined film thickness, then washed by an alkali solution, and then formed again to a desired film thickness.

12. The method for manufacturing a transflective type LCD according to claim 9, wherein said barrier metal film comprises Mo and said reflection metal film comprises Al.

13. The method for manufacturing a transflective type LCD according to claim 5, wherein at the washing by use of UV ray prior to formation of said transparent electrode film, an application quantity of the UV ray is limited down to a value less than 100 mJ.

6. A method for manufacturing a transflective type LCD, in said transflective type LCD having a first substrate provided thereon with a plurality of scanning lines and a plurality of signal lines which are substantially perpendicular to each other and a switching element arranged near each of intersections between said scanning lines and said signal lines, forming a reflection region having a reflection electrode film and a transmission region having a transparent electrode film in each pixel surrounded by said scanning lines and said signal lines and the liquid crystal is sandwiched at a gap between said first substrate and a second substrate which is arranged opposite to said first substrate, the method comprising:

when forming an organic film having irregularities thereon is formed below said reflection electrode film and said transparent electrode film to substantially the same film thickness,

forming a first organic film as scattered in dot;

performing predetermined heat treatment to form protrusions; and

covering moderately by a second organic film to form said predetermined irregularities.

14. A method for manufacturing a transflective type active matrix substrate, said transflective type active matrix substrate being provided with a plurality of scanning lines and a plurality of signal lines which are substantially perpendicular to each other and a switching element arranged near each of intersections between said scanning lines and said signal lines in such a configuration that a reflection region having a reflection electrode film and a transmission region having a transparent electrode film are formed in each pixel surrounded by said scanning lines and said signal lines, the method comprising at least:

depositing a passivation film on a substrate on which said scanning lines, said signal lines, and said switching elements are formed and then forming a first contact hole in a portion (G-D conversion portion) which is provided around said substrate to lead out said signal line by a gate layer;

filling said first contact hole with a predetermined conductive material to connect said G-D conversion portion therewith;

depositing an organic film to almost the same film thickness both in said transmission region and said reflection region, then forming irregularities on the surface and also removing said organic film on a terminal of said switching element to form a second contact hole;

forming a transparent electrode film on said organic film in said transmission region; and

forming a reflection electrode film in such a manner that said reflection electrode film may overlap with said transparent electrode film around an overall periphery thereof by a predetermined width to interconnect said terminal and said reflection electrode film through said second contact hole.

15. A method for manufacturing a transflective type active matrix substrate, said transflective type active matrix substrate being provided with a plurality of scanning lines and a plurality of signal lines which are substantially perpendicular to each other and a switching element arranged near each of intersections between said scanning lines and said signal lines in such a configuration that a reflection region having a reflection electrode film and a transmission region having a transparent electrode film are formed in each pixel surrounded by said scanning line and said signal line, the method comprising at least:

depositing a passivation film on a substrate on which said scanning lines, said signal lines, and said switching elements are formed and then forming a first contact hole in a portion (G-D conversion portion) which is provided around said substrate to lead out said signal line by a gate layer;

depositing an organic film to almost the same film thickness both in said transmission region and said reflection region, then forming irregularities on the surface and also removing said organic film on a terminal of said switching element to form a second contact hole;

forming a transparent electrode film on said organic film in said transmission region and also filling said first contact hole with said transparent electrode film to connect said G-D conversion portion therewith; and

forming a reflection electrode film in such a manner that said reflection electrode film may overlap with said transparent electrode film around an overall periphery thereof by a predetermined width to interconnect said terminal and said reflection electrode film through said second contact hole.

16. A method for manufacturing a transflective type active matrix substrate, said transflective type active matrix substrate being provided with a plurality of scanning lines and a plurality of signal lines which are substantially perpendicular to each other and a switching element arranged near each of intersections between said scanning lines and said signal lines in such a configuration that a reflection region having a reflection electrode film and a transmission region having a transparent electrode film are formed in each pixel surrounded by said scanning line and said signal line, the method comprising at least:

depositing a passivation film on a substrate on which said scanning lines, said signal lines, and said switching elements are formed and then forming a first contact hole in a portion (G-D conversion portion) which is provided around said substrate to lead out said signal line by a gate layer;

depositing an organic film to almost the same film thickness both in said transmission region and said reflection region, then forming irregularities on the surface and also removing said organic film on a terminal of said switching element to form a second contact hole;

forming a transparent electrode film on said organic film in said transmission region; and

forming a reflection electrode film in such a manner that said reflection electrode film may overlap with said transparent electrode film around an overall periphery thereof by a predetermined width, then interconnecting said terminal and said reflection electrode film through said second contact hole and also filling said first contact hole with said reflection electrode film to connect said G-D conversion portion therewith.

17. The method for manufacturing a transflective type active matrix substrate according to claim 16, wherein when said transparent electrode film is formed, said second contact hole is filled with said transparent electrode film.