Liquid crystal display device and electronic device having sensor circuit comprising a transistor and a capacitor

• US 9,952,725 B2
• Filed: 04/21/2015
• Issued: 04/24/2018
• Est. Priority Date: 04/22/2014
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ishitani, Tetsuji, Hatsumi, Ryo, Kusunoki, Koji, Miyake, Hiroyuki
• Primary Examiner(s): Nguyen, Lauren
• Application Number:
  US14/692,297
• Publication Number:
  US 20150301382A1
• Time in Patent Office: 1,099 Days
• 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: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 3/3618 with automatic refresh of the display panel using sense/write circuits

Abstract

A novel liquid crystal display device (LCD) including a touch sensor. The LCD includes a first substrate and a second substrate, which face each other, and a liquid crystal layer. The first substrate is provided with a pixel electrode. The second substrate is provided with a first electrode, a second electrode, and an insulating layer. The pixel electrode overlaps with the first electrode with the liquid crystal layer interposed therebetween. The second electrode overlaps with the first electrode with the insulating layer interposed therebetween. The LCD generates a signal corresponding to a potential of the second electrode. This structure enables a thin and lightweight LCD.

Claims

1. A liquid crystal display device comprising:

a first substrate provided with a pixel electrode;

a second substrate provided with a sensor circuit;

the sensor circuit comprising a transistor and a capacitor; and

a pixel circuit comprising a liquid crystal element;

wherein the capacitor comprises a first electrode, a second electrode, and an insulating layer,

wherein the liquid crystal element comprises the first electrode, the pixel electrode, and a liquid crystal layer,

wherein the first substrate and the second substrate face each other,

wherein the first electrode and the pixel electrode overlap with each other with the liquid crystal layer interposed between the pixel electrode and the first electrode,

wherein the second electrode and the pixel electrode overlap with each other with the insulating layer interposed between the second electrode and the pixel electrode,

wherein a gate of the transistor is electrically connected to the second electrode, and

wherein the transistor is configured to generate a signal corresponding to a potential of the second electrode.

2. The liquid crystal display device according to claim 1, wherein the first substrate and the second substrate are flexible substrates.

3. An electronic device comprising the liquid crystal display device according to claim 1.

4. An electronic device comprising:

the liquid crystal display device according to claim 1; and

at least one of a microphone, a speaker, and a camera.

9. The liquid crystal display device according to claim 1, wherein the first electrode is configured to be supplied with a constant potential.

5. A liquid crystal display device comprising:

a first substrate;

a pixel circuit comprising a liquid crystal element comprising;

a pixel electrode over the first substrate;

a liquid crystal layer over the pixel electrode; and

a first electrode over the liquid crystal layer;

a sensor circuit comprising a transistor and a capacitor, the capacitor comprising;

the first electrode;

an insulating layer over the first electrode; and

a second electrode over the insulating layer; and

a second substrate over the sensor circuit;

wherein the first substrate and the second substrate face each other,

wherein the first electrode and the pixel electrode overlap with each other with the liquid crystal layer interposed between the pixel electrode and the first electrode,

wherein the second electrode and the first electrode overlap with each other with the insulating layer interposed between the second electrode and the first electrode,

wherein a gate of the transistor is electrically connected to the second electrode, and

wherein the transistor is configured to generate a signal corresponding to a potential of the second electrode.

6. The liquid crystal display device according to claim 5, wherein the first substrate and the second substrate are flexible substrates.

7. An electronic device comprising the liquid crystal display device according to claim 5.

8. An electronic device comprising:

the liquid crystal display device according to claim 5; and

at least one of a microphone, a speaker, and a camera.

10. The liquid crystal display device according to claim 5, wherein the first electrode is configured to be supplied with a constant potential.