Liquid crystal display and method of manufacturing the same

• US 7,250,996 B2
• Filed: 09/30/2004
• Issued: 07/31/2007
• Est. Priority Date: 12/09/2003
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation, Fujitsu Limited
• Inventors: Shibasaki, Masakazu, Tashiro, Kunihiro, Ueda, Kazuya, Tasaka, Yasutoshi, Ohmuro, Katsufumi, Yoshida, Hidefumi, Kamada, Tsuyoshi
• Primary Examiner(s): Qi; Mike
• Application Number:
  US10/955,247
• Publication Number:
  US 20050122452A1
• Time in Patent Office: 1,034 Days
• Field of Search: 349/114, 349/61, 349/138, 349/155, 349/130, 349/146
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes

Abstract

The invention relates to a transflective liquid crystal display capable of display in both of transmissive and reflective modes and a method of manufacturing the same and provides a transflective liquid crystal display which can achieve high display characteristics in both of the transmissive and reflective modes. A configuration is employed which includes a liquid crystal display panel having a pair of substrates and a liquid crystal layer sealed between the substrates, a pixel region including a reflective area having a reflector for reflecting light entering from the side of one of the pair of substrates and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates, a backlight unit having a reflector and a light guide plate for reflecting the light which has entered the transmissive area from the side of the one of the pair of substrates and which has been transmitted by the area to cause the light to enter the transmissive area again from the side of the other of the pair of substrates, and a color filter layer formed only in the transmissive area of the pixel region.

Claims

1. A liquid crystal display comprising:

a pair of substrates provided opposite to each other;

a liquid crystal layer sealed between the pair of substrates;

a pixel region including a reflective area having a reflector for reflecting light entering from the side of one of the pair of substrates and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates; and

a thin film transistor formed at each pixel region,

wherein the reflector is formed of the same material as that of a gate electrode or drain electrode of the thin film transistor and has a multi-layer structure constituted by a first metal layer having a high reflectivity and a second metal layer having a lower reflectivity than that of the first metal layer,

the second metal layer is formed above the first metal layer, and

the reflector includes a reflective surface formed of the first metal layer exposed where the second metal layer is removed.

2. A liquid crystal display according to claim 1, wherein the reflective surface is covered by a transparent electrode.

3. A liquid crystal display according to claim 1, further comprising a color filter layer formed such that the transmittance of the reflective area becomes higher than the transmittance of the transmissive area.

4. A liquid crystal display according to claim 3, wherein the reflective area has a transparent layer formed under or above the color filter layer.

5. A liquid crystal display according to claim 3, wherein the color filter layer is removed completely or halfway in the thickness direction of the layer at least in a part of the reflective area.

6. A liquid crystal display according to claim 5, further comprising a transparent electrode which is formed so as to cover the color filter layer and which applies a voltage to the liquid crystal.

7. A liquid crystal display according to claim 6, wherein the reflective area further has a transparent dielectric layer which is formed under or above the color filter layer or between the same layer and the transparent electrode and which makes the thickness of the liquid crystal layer in a reflective section thereof smaller than that in a transmissive section.

8. A liquid crystal display according to claim 7, wherein the transparent dielectric layer is formed in a region where the color filter layer has been removed or formed so as to cover the region.

9. A liquid crystal display according to claim 1, further comprising a reflective section for reflecting light which has entered the transmissive area from the side of one of the pair of substrates and which has been transmitted by the same and for causing the light to enter the transmissive area again from the side of the other of the pair of substrates, wherein the color filter layer is formed only in the transmissive area in the pixel region.

10. A liquid crystal display according to claim 9, further comprising a backlight unit provided on the side of the other of the pair of substrates, wherein the backlight unit includes a light guide plate and the reflective section that is provided behind the light guide plate.

11. A liquid crystal display according to claim 1, further comprising a pattern for forming irregularities, formed of the same material as any of materials of which the thin film transistor is formed, wherein the reflector is formed on the pattern for forming irregularities and wherein at least a part of the surface of the reflector is inclined relative to a substrate surface.

12. A liquid crystal display according to claim 11, wherein the irregularity forming pattern for forming irregularities has a conductor layer formed of the same material as that of the gate electrode of the thin film transistor.

13. A liquid crystal display according to claim 11, wherein the pattern for forming irregularities has a semiconductor layer formed of the same material as that of an active semiconductor layer of the thin film transistor.

14. A liquid crystal display according to claim 11, wherein the pattern for forming irregularities has a dielectric layer formed of the same material as that of a channel protection film of the thin film transistor.

15. A liquid crystal display according to claim 11, wherein the pattern for forming irregularities is formed by patterning a part of a storage capacitor bus line or separated from the storage capacitor bus line.

16. A liquid crystal display according to claim 15, the width of the part of the storage capacitor bus line including the patterned section is greater than the width of other parts of the storage capacitor bus line.

17. A liquid crystal display comprising:

a pair of substrates provided opposite to each other;

a liquid crystal layer sealed between the pair of substrates;

a pixel region including a reflective area having a reflector for reflecting light entering from the side of one of the pair of substrates and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates;

a thin film transistor formed at each pixel region;

a color filter layer formed such that the transmittance of the reflective area becomes higher than the transmittance of the transmissive area; and

a transparent electrode which is formed so as to cover the color filter layer and which applies a voltage to the liquid crystal,

wherein the reflector is formed of the same material as that of a gate electrode or drain electrode of the thin film transistor and includes a reflective surface formed of a metal having a high reflectivity,

the color filter layer is removed completely or halfway in the thickness direction of the layer at least in a part of the reflective area, and

the reflective area further has a transparent dielectric layer which is formed between the transparent electrode and the liquid crystal layer and which decreases an effective voltage applied to the liquid crystal layer.