DISPLAY DEVICE WITH TOUCH SENSOR

• US 20180299995A1
• Filed: 06/22/2018
• Published: 10/18/2018
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Noguchi, Koji, Takama, Daisuke, Kida, Yoshitoshi
• Granted Patent: US 10,768,755 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 2201/12 electrode
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A common electrode for a display, which is originally provided in a liquid crystal display element, is also used as one (drive electrode) of a pair of electrodes for a touch sensor, and the other (detection-electrode-for-the-sensor) of the pair of electrodes is newly formed. An existing common drive signal as a drive signal for display is used in common for a drive signal for the touch sensor. A capacitance is formed between the common electrode and the detection-electrode-for-the-sensor, and touch detection is performed by utilizing a change of this capacitance caused by a finger touch of a user. Thus, a display device with a touch sensor is also applicable to a mobile device in which electric potential of the user is inconstant in many cases. The newly-provided electrode is only the detection-electrode-for-the-sensor, and it is unnecessary to newly prepare a drive signal for the touch sensor.

Claims

1. A display device having a capacitive touch sensor, comprising:

a first substrate;

a second substrate facing the first substrate;

a display function layer having an image display function, the display function layer being interposed between the first substrate and the second substrate, the second substrate having (a) a display function layer side facing the display function layer and (b) an upper surface side facing away from the display function layer side;

a plurality of display pixel electrodes;

a common electrode facing the display pixel electrodes, the display pixel electrodes and the common electrode being disposed between the first substrate and the display function layer;

a control circuit that controls display of an image by applying a voltage to the display pixel electrode and the common electrode based on an image signal;

a touch detection electrode for the capacitive touch sensor, the touch detection electrode overlapping the common electrode; and

a touch detection circuit that detects a position touched by an object based on a detection signal obtained from the touch detection electrode, the touch detection electrode being disposed on the upper surface side of the second substrate.

2. The display device of claim 1, wherein:

the touch detection electrode comprises a plurality of individual electrodes, and

each of the individual electrodes is stripe-shaped.

3. The display device of claim 1, wherein:

the touch detection electrode comprises a plurality of individual electrodes, and

each of the individual electrodes is rectilinear in shape.

4. The display device of claim 1, comprising a dielectric between the touch detection electrode and the display function layer.

5. The display device of claim 4, wherein the dielectric comprises a color filter.

6. The display device of claim 1, wherein a drive voltage that is applied to the common electrode by the control circuit is also utilized as a drive signal for the capacitive touch sensor.

7. The display device of claim 6, wherein:

the common electrode is divided into a plurality of patterns, and

the drive signal for the capacitive touch sensor is sequentially applied in a time-divisional manner to each of the plurality of patterns of the common electrode.

8. The display device of claim 1, wherein both of the touch detection electrode and the common electrode are divided into a respective plurality of patterns.

9. The display device of claim 1, wherein the touch detection circuit detects a touch based on a capacitance formed between the common electrode and the touch detection electrode.

10. The display device of claim 1, wherein:

the touch detection electrode comprises a plurality of individual electrodes disposed in a matrix, and

the common electrode is a single electrode overlapping the patterns of the touch detection electrode.

11. The display device of claim 1, wherein:

the touch detection electrode comprises a plurality of individual electrodes disposed in a matrix, and

the common electrode is divided into a plurality of stripe-shaped patterns.