Display device, display module, and electronic device

• US 9,964,799 B2
• Filed: 03/10/2016
• Issued: 05/08/2018
• Est. Priority Date: 03/17/2015
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hirakata, Yoshiharu
• Primary Examiner(s): Nguyen, Sang V
• Application Number:
  US15/066,040
• Publication Number:
  US 20160274421A1
• Time in Patent Office: 789 Days
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/13356 characterised by the placement of the optical elements
• CPC Class Codes: G02F 1/133562 on the viewer side

Abstract

A reflective liquid crystal display device capable of favorable display is provided. A reflective liquid crystal display device having a high aperture ratio is provided. A reflective film is provided on the counter substrate side. An oxide conductor film is used as an electrode of a capacitor or a liquid crystal element. Specifically, a display device includes a transistor, an insulating film, a capacitor, a liquid crystal element, and a reflective film. The transistor is electrically connected to the capacitor and the liquid crystal element. The transistor includes an oxide semiconductor film. The capacitor transmits visible light. The capacitor or the liquid crystal element includes an oxide conductor film as at least one of a pair of electrodes. The oxide semiconductor film is opposite to the oxide conductor film with the insulating film therebetween. The reflective film is opposite to the transistor with the liquid crystal element therebetween.

Claims

1. A display device comprising:

a transistor comprising an oxide semiconductor film;

an insulating film over the transistor;

a liquid crystal element electrically connected to the transistor, over the insulating film, the liquid crystal element comprising a pixel electrode, a common electrode, and a liquid crystal layer;

a color filter layer;

a reflective film over the liquid crystal element and the color filter layer; and

a counter substrate over the reflective film,

wherein the pixel electrode of the liquid crystal element comprises a first oxide conductor film comprising gallium, and

wherein the reflective film is positioned between the common electrode of the liquid crystal element and the counter substrate, and between the color filter layer and the counter substrate.

2. The display device according to claim 1,

wherein the oxide semiconductor film comprises an In-M-Zn oxide, and

wherein the M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf.

3. The display device according to claim 1,

wherein the transistor comprises a first gate electrode and a second gate electrode with the oxide semiconductor film therebetween, and

wherein one of the first gate electrode and the second gate electrode comprises a second oxide conductor film comprising gallium.

4. The display device according to claim 1, further comprising a touch sensor.

5. A display module comprising:

the display device according to claim 1; and

a flexible printed circuit.

6. An electronic device comprising:

the display device according to claim 1;

a flexible printed circuit; and

at least one of an antenna, a battery, a housing, a speaker, a microphone, an operation switch, and an operation button.

13. The display device according to claim 1, wherein the common electrode of the liquid crystal element is electrically connected to the reflective film.

14. The display device according to claim 1, wherein the common electrode of the liquid crystal element comprises a second oxide conductor film comprising an In—

Ga—

Zn oxide.

15. The display device according to claim 1, further comprising a coloring film between the reflective film and the common electrode of the liquid crystal element.

7. A display device comprising:

a transistor comprising an oxide semiconductor film;

an insulating film over the transistor;

a capacitor electrically connected to the transistor;

a liquid crystal element electrically connected to the transistor, over the insulating film, the liquid crystal element comprising a pixel electrode, a common electrode, and a liquid crystal layer;

a color filter layer;

a reflective film over the liquid crystal element and the color filter layer; and

a counter substrate over the reflective film,

wherein the pixel electrode of the liquid crystal element comprises a first oxide conductor film comprising an In—

Ga—

Zn oxide,

wherein one of a pair of electrodes of the capacitor comprises a second oxide conductor film comprising an In—

Ga—

Zn oxide, and

wherein the reflective film is positioned between the common electrode of the liquid crystal element and the counter substrate, and between the color filter layer and the counter substrate.

8. The display device according to claim 7,

wherein the oxide semiconductor film comprises an In-M-Zn oxide, and

wherein the M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf.

9. The display device according to claim 7,

wherein the transistor comprises a first gate electrode and a second gate electrode with the oxide semiconductor film therebetween, and

wherein one of the first gate electrode and the second gate electrode comprises a third oxide conductor film comprising an In—

Ga—

Zn oxide.

10. The display device according to claim 7, further comprising a touch sensor.

11. A display module comprising:

the display device according to claim 7; and

a flexible printed circuit.

12. An electronic device comprising:

the display device according to claim 7;

a flexible printed circuit; and

at least one of an antenna, a battery, a housing, a speaker, a microphone, an operation switch, and an operation button.

16. The display device according to claim 7, wherein the common electrode of the liquid crystal element is electrically connected to the reflective film.

17. The display device according to claim 7, wherein the common electrode of the liquid crystal element comprises a third oxide conductor film comprising an In—

Ga—

Zn oxide.

18. The display device according to claim 7, further comprising a coloring film between the reflective film and the common electrode of the liquid crystal element.