Transflective type LCD and method for manufacturing the same

• US 6,853,421 B2
• Filed: 07/26/2002
• Issued: 02/08/2005
• Est. Priority Date: 08/06/2001
• Status: Expired due to Term

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NEC Corporation, NEC LCD Technologies Limited (NEC Corporation)
• Inventors: Ikeno, Hidenori, Kimura, Shigeru, Sakamoto, Michiaki, Morio, Kenji, Shinohara, Masaki, Ihida, Satoshi, Saeki, Kazurou
• Primary Examiner(s): Chowdhury, Tarifur R.
• Assistant Examiner(s): Caley, Michael H
• Application Number:
  US10/205,365
• Publication Number:
  US 20030030768A1
• Time in Patent Office: 928 Days
• Field of Search: 349/113, 349/114, 349/122, 349/138
• 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. A transflective type LCD having a plurality of pixels, said LCD comprising:

a first substrate;

a second substrate arranged facing said first substrate with a gap therebetween;

a plurality of longitudinally extending scanning lines;

a plurality of signal lines extending longitudinally substantially perpendicular to said scanning lines to intersect said scanning lines, said intersecting signal lines and scanning lines surrounding pixels of said LCD;

a switching element arranged near each of the intersections between said scanning lines and said signal lines on said first substrate;

a transmission region in which a transparent electrode film is formed;

a reflection region in which a reflection electrode film is formed, said transmission region and said reflection region being provided in each pixel, each of said transparent electrode film in said transmission region and said reflection electrode film in said reflection region comprising a plurality of contiguous undulations;

a liquid crystal sandwiched in the gap between said first substrate and said second substrate; and

an organic film in the gap and below said transparent electrode film and said reflection electrode film, to underlie the undulations, and having substantially the same film thickness below said transparent electrode film as below said reflection electrode film, so that the gap is substantially the same in said transmission region and in said reflection region.

2. The transflective type LCD according to claim 1, wherein said reflection electrode film is formed on the side of the pixel where said switching element is arranged, with a terminal of said switching element connected with said reflection electrode film via a through hole formed in said organic film, and with said transparent electrode film connected with said reflection electrode film in an overlap region thereof.

3. The transflective type LCD according to claim 1, wherein said switching element includes a gate layer connected with one of said reflection electrode film and said transparent electrode film at an edge of said first substrate.

4. The transflective type LCD according to claim 1, further comprising a λ

/4 plate and a polarizing plate on a side of each of said first substrate and said second substrate opposite to the facing sides, wherein;

said polarizing plates are arranged so that the polarization axes thereof are perpendicular to each other; and

said liquid crystal has a twist angle of 72°

.

5. The transflective type LCD according to claim 1, wherein the film thickness below said transparent electrode film is within 1 μ

m of the film thickness below said reflection electrode film.

6. The transflective type LCD according to claim 1, wherein in each pixel said reflection electrode film has a window therein in which said transmission region is formed, with said reflection electrode film and said transparent electrode film overlapping around a periphery of said window.

7. A transflective type LCD having a plurality of pixels, said LCD comprising:

a liquid crystal;

a transmission region including a transparent electrode film;

a reflection region including a reflection electrode film, each of said transparent electrode film in said transmission region and said reflection electrode film in said reflection region comprising a plurality of contiguous undulations; and

an organic film provided below said transparent electrode film and said reflection electrode film and having substantially the same film thickness below said transparent electrode film as below said reflection electrode film.

8. The transflective type LCD according to claim 7, further comprising a switching element having a terminal connected with said reflection electrode film.

9. The transflective type LCD according to claim 7, wherein said transparent electrode film is connected with said reflection electrode film in an overlap region of said films.

10. The transflective type LCD according to claim 7, further comprising a λ

/4 plate and a polarizing plate on each side of said films and arranged so that polarization axes thereof are perpendicular to each other,

wherein said liquid crystal has a twist angle of 72°

.

11. A transflective type LCD having a plurality of pixels, and including:

a first substrate;

a second substrate arranged facing said first substrate with a gap therebetween;

a transmission region in which a transparent electrode film is formed;

a reflection region in which a reflection electrode film is formed, said transmission region and said reflection region being provided in each pixel of said LCD, each of said transparent electrode film in said transmission region and said reflection electrode film in said reflection region comprising a plurality of contiguous undulations;

a liquid crystal sandwiched in the gap between said first substrate and said second substrate; and

an organic film in the gap and below said reflection electrode film and said transparent electrode film and having substantially the same film thickness below said transparent electrode film as below said reflection electrode film, so that the gap is substantially the same in said transmission region and in said reflection region.

12. The transflective type LCD according to claim 11, wherein in each pixel said reflection electrode film has a window therein in which said transmission region is formed, with said reflection electrode film and said transparent electrode film overlapping around a periphery of said window.