Transflective-type liquid crystal display device and method of fabricating the same

• US 7,719,639 B2
• Filed: 09/21/2006
• Issued: 05/18/2010
• Est. Priority Date: 10/16/2003
• Status: Expired due to Fees

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LF Gisplay Company Limited
• Inventors: Yang, Joon Young, Park, Yong In, Kim, Sang Hyun
• Primary Examiner(s): Rude; Timothy
• Application Number:
  US11/524,433
• Publication Number:
  US 20070013841A1
• Time in Patent Office: 1,335 Days
• Field of Search: None
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• 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 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence

Abstract

A transflective-type liquid crystal display device includes a plurality of gate and data lines crossing each other on a substrate to define a plurality of pixel regions, a thin film transistor at each crossing of the gate and data lines, the thin film transistor including a semiconductor layer, and source and drain electrodes contacting source and drain regions, respectively, a projection seed pattern within the pixel region along a same layer as the semiconductor layer of the thin film transistor, and a reflective electrode contacting the drain electrode of the thin film transistor and having a reflective projection corresponding to the projection seed pattern.

Claims

1. A transflective-type liquid crystal display device, comprising:

a substrate having a plurality of gate and data lines crossing each other to define a plurality of pixel regions;

a buffer layer on the substrate, the buffer layer including a plurality of first portions each having a first thickness and a plurality of second portions each having a second thickness less than the first thickness;

a polysilicon layer on the buffer layer, the polysilicon layer including a plurality of first portions each disposed on one of the plurality of first portions of the buffer layer, one of the second portions including source and drain regions;

a gate insulating layer on the first portions of the polysilicon layer and the first and second portions of the buffer layer;

a gate electrode and the plurality of gate lines on the gate insulating layer;

a first insulating interlayer on the gate electrode and the first and second portions of the buffer layer;

first and second contact holes through the gate insulating layer and the first insulating interlayer exposing portions of the source and drain regions;

source and drain electrodes in the first and second contact holes contacting the exposed portions of the source and drain regions, respectively;

a passivation layer on the source and drain electrodes and the first and second portions of the buffer layer, the passivation layer including a third contact hole exposing a portion of the drain electrode;

a transparent electrode on the passivation layer and contacting the exposed portion of the drain electrode in the third contact hole of the passivation layer;

a second insulating interlayer on the transparent electrode, the passivation layer, and the first and second portions of the buffer layer, the second insulating interlayer having a fourth contact hole exposing a portion of the transparent electrode; and

a reflecting electrode on the second insulating interlayer and the first and second portions of the buffer layer, the reflecting electrode contacting the exposed portion of the transparent electrode through the fourth contact holes of the second insulating interlayer.

2. The device according to claim 1, wherein the reflective electrode covers the source and drain electrodes.

3. The device according to claim 1, wherein each of the gate insulating layer, the first insulating interlayer, the passivation layer, the transparent electrode, the second insulating interlayer, and the reflective electrode overlapping the plurality of first portions of the buffer layer have a plurality of protrusions.

4. The device according to claim 3, wherein a centerline of a curvature of each of the protrusions corresponds to the plurality of first portions of the buffer layer.

5. The device according to claim 1, wherein each of the first and second portions of the buffer layer are coplanar.

6. The device according to claim 1, wherein each of the source and drain electrodes extend past the source and drain regions, respectively, and overlap two of the plurality of second portions of the buffer layer.

7. The device according to claim 1, wherein the source and drain regions and each of the plurality of first portions of the polysilicon layer are doped with impurities.

8. The device according to claim 7, wherein each of the plurality of first portions of the polysilicon layer are within a reflective part of one of the pixel regions.