Liquid crystal display device and touch panel

• US 9,366,896 B2
• Filed: 10/10/2013
• Issued: 06/14/2016
• Est. Priority Date: 10/12/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Hirakata, Yoshiharu, Kubota, Daisuke, Yamashita, Akio
• Primary Examiner(s): Crockett, Ryan
• Application Number:
  US14/050,875
• Publication Number:
  US 20140104507A1
• Time in Patent Office: 978 Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1341 Filling or closing of cells
• CPC Class Codes: G02F 1/13415 Drop filling process
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A semiconductor layer of a transistor is formed of an oxide semiconductor film including a crystal part. An organic resin film covering the transistor is formed. By treatment such as drying treatment on the organic resin film in a cell process, variations in the threshold voltage of the oxide semiconductor transistor due to moisture can be suppressed. A common electrode faces a pixel electrode. The common electrode and the pixel electrode are formed over the organic resin film with an insulating film provided therebetween. Therefore, a capacitor can be provided to a liquid crystal element if a pixel does not include a wiring for a storage capacitor. An antistatic electrode is provided on the outer side of a color filter substrate and the capacitance between the antistatic electrode and the common electrode is utilized, so that the liquid crystal display device can be used as a touch panel.

Claims

1. A method for manufacturing a liquid crystal display device comprising the steps of:

forming a transistor over a first substrate, the transistor comprising an oxide semiconductor film which includes a channel formation region;

forming an insulating film over the transistor;

forming a pixel electrode over the insulating film, the pixel electrode being in electrical contact with the transistor;

forming a first orientation film over the pixel electrode;

heating the first substrate after forming the first orientation film under reduced pressure to perform dry treatment;

forming a second orientation film over a second substrate;

heating the second substrate after forming the second orientation film under reduced pressure to perform dry treatment;

dropping a liquid crystal material on the second orientation film after heating the second substrate; and

bonding the first substrate and the second substrate with each other with the liquid crystal material interposed therebetween,

wherein the steps of heating the first substrate, heating the second substrate, and dropping the liquid crystal material are successively performed without exposure to air.

2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the step of heating the first substrate is performed at a temperature higher than or equal to 100°

C.

3. The method for manufacturing a liquid crystal display device according to claim 1, wherein the step of heating the second substrate is performed at a temperature higher than or equal to 100°

C.

4. The method for manufacturing a liquid crystal display device according to claim 1, wherein the step of bonding is performed in an atmosphere at a dew point of lower than or equal to −

60°

C.

5. The method for manufacturing a liquid crystal display device according to claim 1, wherein the oxide semiconductor film contains indium, gallium, and zinc.

6. The method for manufacturing a liquid crystal display device according to claim 1, wherein the oxide semiconductor film comprises a crystal part.

7. The method for manufacturing a liquid crystal display device according to claim 6, wherein a c-axis of a crystal in the crystal part is aligned in a direction substantially perpendicular to a top surface of the oxide semiconductor film.