Touch detection device and display device having touch sensor function

• US 9,274,653 B2
• Filed: 06/01/2010
• Issued: 03/01/2016
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Ishizaki, Koji, Noguchi, Kouji, Takeuchi, Takeya, Nakanishi, Takayuki, Teranishi, Yasuyuki
• Primary Examiner(s): Awad, Amr
• Assistant Examiner(s): MATTHEWS, ANDRE L
• Application Number:
  US12/791,667
• Publication Number:
  US 20100328255A1
• Time in Patent Office: 2,100 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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: G06F 3/047 using sets of wires, e.g. crossed wires

Abstract

A touch detection device includes: a detection surface; a plurality of sensor lines formed from a plurality of types of wiring lines having a different line capacitance; and a touch detection unit which detects an electric variation generated in a plurality of the sensor lines in response to touch or proximity of a detection target object to the detection surface, wherein the touch detection unit has an operational circuit for generating a detection signal representing the electric variation by performing an operation process using a line capacitance ratio for a plurality of outputs from a plurality of types of the sensor lines neighboring to one another with a different line capacitance.

Claims

1. A touch detection device comprising:

a detection surface;

a plurality of sensor lines formed from a plurality of wiring lines, wherein a plurality of adjacent independent sensor lines are sequentially varying sensor lines, each sensor line of the sequence of adjacent sensor lines having a substantially different length and a corresponding substantially different capacitance than a preceding sensor line in the sequence; and

a touch detection unit that detects an electric variation generated in a plurality of the sensor lines associated with touch or proximity of a detection target object to the detection surface,

wherein the touch detection unit has an operational circuit for generating a detection signal corresponding to the detected electric variation at the plurality of the adjacent independent sensor lines.

2. The touch detection device according to claim 1, wherein a plurality of the sensor lines are formed from a plurality of M types of wiring lines that have the different length for each type and are arranged in parallel to one another, and M sensor lines neighboring to one another are a different type.

3. The touch detection device according to claim 2, wherein the M sensor lines are formed from wiring lines having a same material, a same thickness, a same width, and a plurality of different lengths,

wherein each of the M sensor lines has a length which is a K multiple (where, K=1 to N) of a length L of an elementary sensor line having a shortest length, and

wherein the operational circuit obtains the detection signal by selecting two sensor lines including a longest sensor line from the M sensor lines, sampling two outputs from the two sensor lines at a timing corresponding to a ratio of the lengths of the two selected sensor lines, and performing a difference operation for sampling values.

4. The touch detection device according to claim 3, wherein the coefficients M and N are set to 3.

5. The touch detection device according to claim 2, wherein the M sensor lines are formed from wiring lines having a same material, a same thickness, a same width, and a plurality of different lengths,

wherein each of the M sensor lines has a length which is a K multiple (where, K=1 to N) of a length L of an elementary sensor line having a shortest length, and

wherein the operational circuit obtains the detection signal by selecting two sensor lines from the M sensor lines, obtaining a difference of outputs for the two selected sensor lines of which a ratio of lengths is set to k (where, k is a natural number equal to or larger than 2), and removing the obtained difference with (k−

1).

6. The touch detection device according to claim 2, wherein one of the operation circuits and another operation circuit are connected to the same sensor line, and different types of sensor lines are arranged in symmetry with respect to the sensor line common to the two operational circuits.

7. The touch detection device according to claim 2, wherein the different types of M sensor lines are periodically repeatedly arranged.

8. The touch detection device according to claim 1, wherein a plurality of the sensor lines are formed from a plurality of M types of wiring lines that have the different length for each type and are arranged in parallel to one another, and wherein the touch detection device further includes

a plurality of driving electrodes, each of which is capacitively coupled to a plurality of the sensor lines, arranged in parallel to extend in a direction different from that of a plurality of the sensor lines, and

a scan driving unit that sequentially voltage-driving (scanning) a plurality of the driving electrodes from a driving electrode of one end to a driving electrode of the other end.

9. The touch detection device according to claim 7, wherein the touch detection unit obtains a position of the detection target object based on the detection signal generated from the operational circuit and time information synchronized with the scanning of the scan driving unit.

10. The touch detection device according to claim 2, wherein each of the operational circuits for each of the M sensor lines that neighbor to one another and have a different type includes a reset switch for simultaneously resetting electric potentials of the sensor lines in all of the operational circuits.

11. The touch detection device according to claim 2, further comprising a conductive layer for shielding a sensor line of a type having a shortest length out of the M sensor lines.

12. A display device having a touch sensor function, the display device comprising:

a display surface;

a plurality of image signal lines;

a display function layer that changes display of the display surface in response to signal voltages applied to a plurality of the image signal lines;

a plurality of sensor lines formed from wiring lines, wherein a plurality of adjacent independent sensor lines are sequentially varying sensor lines, each sensor line of the sequence of adjacent sensor lines having a substantially different length and a corresponding substantially different capacitance than a preceding sensor line in the sequence; and

a touch detection unit that detects an electric variation generated from a plurality of the sensor lines in response to touch or proximity of a detection target object to the display surface,

wherein a plurality of the sensor lines are formed from different types of wiring lines having a different line capacitance due to the different length for each type, and

wherein the touch detection unit includes an operational circuit for generating a detection signal corresponding to the detected electric variation at the plurality of the adjacent independent sensor lines.

13. The display device according to claim 12, wherein a plurality of the sensor lines are formed from a plurality of M types of wiring lines that have the different length for each type and are arranged in parallel to one another, and a plurality of M sensor lines neighboring to one another are a different type, and

wherein the touch detection unit has the operational circuit provided for each of the M sensor lines that neighbor to one another and are a different type.

14. The display device according to claim 13, wherein the M sensor lines are formed from wiring lines having a same material, a same thickness, a same width, and a plurality of different lengths,

wherein each of the M sensor lines has a length which is a K multiple (where, K=1 to N) of a length L of an elementary sensor line having a shortest length, and

wherein the operational circuit obtains the detection signal by selecting two sensor lines including a longest sensor line from the M sensor lines, sampling two outputs from the two sensor lines at a timing corresponding to a ratio of the lengths of the two selected sensor lines, and performing a difference operation for sampling values.

15. The display device according to claim 13, wherein the sensor line having a maximum length out of the M sensor lines intersects with two opposite sides of an effective display area of the display surface, and the sensor line having a minimum length out of the M sensor lines is disposed outside the effective display area.

16. A display device having a touch sensor function, the display device comprising:

a plurality of pixels connected to one another by a plurality of scanning lines and a plurality of image signal lines, each of the pixels having a switch for writing a voltage of corresponding one of the image signal lines in response to a voltage applied to corresponding one of the scanning lines;

a plurality of pixel electrodes provided for each pixel and arranged in a matrix;

m driving electrodes that are arranged opposite the pixel electrodes have a pitch length one or more times a pitch length of the pixel electrodes in a scanning direction which is an arrangement direction of one side of the pixel electrode and are arranged with the same interval in the scanning direction;

a plurality of sensing electrodes having an electrostatic capacitance between each of the m driving electrodes;

a display function layer having an image display function in response to a signal voltage applied between the pixel electrode and the driving electrode that face each other;

a write driving scanning unit that performs a write operation for writing voltages of a predetermined number of the image signal lines by turning on a predetermined number switches for a predetermined number of the pixel electrodes lined up in a direction perpendicular to the scanning direction and repeats a shift operation that sequentially switches a predetermined number of pixel electrodes, in the scanning direction;

an AC driving scanning unit that drives, with an AC voltage, s driving electrodes (where, 1≦

s<

m) defined from the m driving electrodes under a condition that driving electrodes opposite to a predetermined number of the pixel electrodes as a write target are included, and shills the s driving electrodes as an AC driving target in the scanning direction to satisfy the condition; and

a touch detection unit that detects a variation in a voltage at one or more sensing electrodes,

wherein a plurality of adjacent independent sensing electrodes are sequentially varying independent sensing electrodes, each sensing electrode of the sequence of adjacent sensing electrodes having a substantially different length and a corresponding substantially different capacitance than a preceding sensing electrode in the sequence, and

the touch detection unit includes an operational circuit for generating a detection signal corresponding to a variation in a voltage at a plurality of the sensing electrodes by performing an operation process using an output difference and a line capacitance ratio which are for a plurality of outputs from a plurality of sensing electrodes that have a different length.

17. The display device according to claim 16, wherein the write driving scanning unit selects s consecutive driving electrodes (where, s is equal to or larger than 2) from the m driving electrodes and drives, with an AC voltage, the s selected driving electrodes,

where a signal having a reference electric potential of an image signal repeatedly changing between two levels in response to an AC driving voltage of the driving electrode is applied to a plurality of the image signal lines, and

wherein a plurality of the image signal lines and a plurality of the sensing electrodes are arranged in a parallel stripe shape extending in the same direction.

18. The display device according to claim 16, wherein a plurality of the sensing electrodes are formed from a plurality of M types of wiring lines that have the different length for each type and are arranged in parallel to one another, and a plurality of M sensing electrodes neighboring to one another are a different type, and

wherein the touch detection unit has the operational circuit provided for each of the M detection electrodes that neighbor to one another and are a different type.

19. The display device according to claim 18, wherein the M sensing electrodes are formed from wiring lines having a same thickness, a same width, a same material, and a plurality of different lengths,

wherein each of the M sensor lines has a length which is a K multiple (where, K=1 to N) of a length L of an elementary sensing electrode having a shortest length, and

wherein the operational circuit obtains the detection signal by selecting two detection electrode sensor lines including a longest sensor line from the M sensor lines, sampling two outputs from the two sensing electrodes at a timing corresponding to a ratio of the lengths of the two selected sensing electrodes, and performing a difference operation.

20. The display device according to claim 16, wherein a plurality of the driving electrodes are arranged at a the side of the display surface.