JP2011242966A - Touch sensor, touch screen and information transmission method using the touch sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch sensor, a touch screen and an information transmission method using the touch sensor that avoid increase in size and cost and have both touch sensor and information transmission functions.SOLUTION: The touch sensor according to the present invention comprises an electrode; detecting means that detects a change of capacitance of the electrode; and setting means that connects the electrode to the detecting means for detecting a contact, makes the electrode grounded when first information is transmitted, and makes the electrode floated when second information is transmitted.

Description

  The present invention relates to a touch sensor that detects a touch by a finger or an electrically grounded conductor, a touch panel, and an information transmission method using the touch sensor. In particular, the present invention relates to a touch sensor, a touch panel, and an information transmission method using the touch sensor that transmit information to the other party along with the detection of touch.

  One method for transmitting data between portable terminals is short-range wireless communication using infrared rays or the like. An example of the appearance of a mobile terminal capable of short-range wireless communication is shown in FIGS. FIG. 6A is a front view of the mobile terminal, on which a display panel 61 is arranged for the user to confirm information. As the display panel 61, an opportunity to adopt a touch panel capable of detecting a touch by a finger or a ground conductor is increasing. On the other hand, FIG. 6B is a rear view of the portable terminal, in which a camera 62 and short-range communication modules 63 and 64 used for short-range wireless communication are arranged.

  As described above, when the user confirms information and transmits data with another mobile terminal, the display panel 61 for displaying information on the mobile terminal and the short-range communication module 63 used for short-range wireless communication, 64 must be mounted respectively. Therefore, Patent Document 1 discloses a technique for transmitting data using a touch panel mounted on a mobile terminal.

  The transmitting-side portable terminal disclosed in Patent Document 1 changes the electrostatic field strength of the touch panel according to data to be transmitted. On the other hand, the receiving-side mobile terminal extracts the data as data by detecting a change in the electrostatic field strength of the touch panel of the transmitting-side mobile terminal. Since the portable terminal of Patent Document 1 uses a touch panel included in the portable terminal as a display unit and an input unit for data transmission, there is no need to separately install a short-range communication module or the like for data transmission between terminals.

JP 2009-253478 A

  However, in the technique of Patent Document 1, it is necessary to change the electrostatic field strength formed on the touch panel of the transmission-side portable terminal in various ways depending on the data to be transmitted. And it is necessary to newly provide a circuit for changing the electrostatic field intensity according to the transmission data. Therefore, the cost increases and there is a limit to downsizing of the device.

  The present invention has been made in view of the above problems, and can avoid an increase in size and cost, and a touch sensor, a touch panel, and a touch panel having both a touch sensor function and an information transmission function. An object of the present invention is to provide an information transmission method using a sensor.

  In order to achieve the above object, a touch sensor according to the present invention includes an electrode, a detection unit that detects a change in capacitance of the electrode, and, when detecting a touch, the electrode is connected to the detection unit, and the first information And setting means for placing the electrode in a floating state when transmitting the second information.

  In order to achieve the above object, a touch panel according to the present invention includes a display panel unit and a touch panel unit disposed on the display panel unit. Here, the touch panel unit is characterized in that the touch sensor is formed of a transparent member.

  In order to achieve the above object, an information transmission method using a touch sensor according to the present invention monitors a change in capacitance of an electrode when detecting a touch, and grounds an electrode when transmitting first information. When the second information is transmitted, the electrode is set in a floating state.

  In the touch sensor, the touch panel, and the information transmission method using the touch sensor according to the present invention, the electrodes are connected to the detection unit when the touch is detected. By monitoring the change in the capacitance of the electrode by the detecting means, it operates as a general touch sensor. On the other hand, when transmitting 1st information, an electrode is made into a grounding state. Furthermore, when transmitting 2nd information, an electrode is made into a floating state. Therefore, the reception side touch sensor can determine whether the first information is transmitted or the second information is transmitted by detecting whether the electrode of the transmission side touch sensor is in a ground state or a floating state. When information is extracted by detecting the ground state or floating state of the electrode, there is no need to mount a circuit or the like for changing the electrostatic field strength.

  Accordingly, an increase in size and cost can be avoided, and a touch sensor having both functions of a touch sensor function and an information transmission function, a touch panel, and an information transmission method using the touch sensor can be provided. .

1 is an example of a block diagram of a touch sensor 10 according to a first embodiment of the present invention. It is an example of the block diagram of the touch sensors 21 and 26 which concern on the 2nd Embodiment of this invention. It is an example of (a) side view and (b) front view of the touch panel which concerns on the 3rd Embodiment of this invention. The side view which shows the state at the time of performing data communication in the touchscreen which concerns on the 3rd Embodiment of this invention. It is an example of the schematic block diagram of the touchscreen which concerns on the 4th Embodiment of this invention. It is an example of (a) front view and (b) rear view of a general portable terminal.

(First embodiment)
A first embodiment of a touch sensor according to the present invention will be described. The touch sensor according to the present embodiment detects a touch by a finger or an electrically grounded conductor and transmits information to the touch sensor on the receiving side. FIG. 1 shows a block diagram of a touch sensor according to the present embodiment. The reception-side touch sensor can have the same configuration as the touch sensor shown in FIG.

  In FIG. 1, the touch sensor 10 includes an electrode 11, a detection unit 12, and a setting unit 13.

  The electrode 11 allows charge to flow when the user touches the touch sensor 10 using a finger or a ground conductor. When connected to the electrode 11, the detection means 12 is electrostatically coupled to the electrode 11 and monitors whether there is a change in capacitance. When the capacitance changes due to the flow of electric charge from the electrode 11, the detection means 12 detects the change in the capacitance and determines that there is a touch with a finger or a ground conductor.

  The setting means 13 connects the electrode 11 to the detection means 12 when detecting a touch. When the electrode 11 is connected to the detection unit 12, the touch sensor 10 functions as a normal touch sensor. On the other hand, the setting means 13 sets the electrode 11 to the ground state when transmitting the first information. Further, the setting means 13 places the electrode 11 in a floating state when transmitting the second information.

  Here, the touch sensor on the information receiving side is coupled with the electrode 11 of the touch sensor 10 and monitors the change in capacitance. When the capacitance changes, it is determined that the electrode 11 of the touch panel 10 is in the ground state, and it is determined that the first information is transmitted from the touch panel 10. On the other hand, when the capacitance does not change, it is determined that the electrode 11 of the touch panel 10 is in a floating state, and it is determined that the second information is transmitted from the touch panel 10.

  As described above, the touch sensor 10 according to the present embodiment can transmit information only by adding the setting unit 13 in addition to the electrode 11 and the detection unit 12 included in the normal touch sensor. Therefore, an increase in size and cost can be avoided, and a touch sensor having both a touch sensor function and an information transmission function can be provided.

(Second Embodiment)
A second embodiment will be described. FIG. 2 shows a configuration diagram of the touch sensor according to the present embodiment. In FIG. 2, the touch sensor includes two touch sensors 21 and 26. Hereinafter, 21 will be described as a transmission side touch sensor and 26 as a reception side touch sensor.

  In FIG. 2, the transmission-side touch sensor 21 includes four sensor electrodes 22, four switches 23 connected to the sensor electrodes 22, four detection circuits 24 connected to the switches 23, and a CPU 25, respectively. .

  Each sensor electrode 22 is connected to a detection circuit 24 when detecting a touch of a finger or an electrically grounded conductor. On the other hand, when performing data transmission, each of the sensor electrodes 22 is in an electrically floating state (hereinafter referred to as a floating state) or a grounded state.

  Each switch 23 includes an electrode side terminal 23a, a circuit side terminal 23b, a floating terminal 23c, and a ground terminal 23d. Each switch 23 connects the electrode side terminal 23a to any one of the circuit side terminal 23b, the floating terminal 23c, and the ground terminal 23d based on the control from the CPU 25. The sensor electrode 22 is connected to the detection circuit 24 by connecting the electrode side terminal 23a to the circuit side terminal 23b. By connecting the electrode side terminal 23a to the floating terminal 23c, the sensor electrode 22 is in a floating state. By connecting the electrode side terminal 23a to the ground terminal 23d, the sensor electrode 22 is in a ground state. Here, the switch 23 corresponds to a setting means in claims.

  The detection circuit 24 is connected to the sensor electrode 22 and capacitively coupled to the sensor electrode 22 when detecting a touch of a finger or a ground conductor. When a finger or a ground conductor touches the sensor electrode 22, the detection circuit 24 detects a change in electrostatic capacity associated with the touch and notifies the CPU 25 that the touch has been made.

  The CPU 25 controls each component of the transmission side touch sensor 21. In the present embodiment, the CPU 25 controls each switch 23 to cause the transmission-side touch sensor 21 to function as either a general touch sensor or a data transmission member. When the CPU 25 causes the transmission-side touch sensor 21 to function as a touch sensor, the CPU 25 controls the switch 23 to connect the sensor electrode 22 to the detection circuit 24. On the other hand, when the CPU 25 causes the transmission-side touch sensor 21 to function as a data transmission member, the CPU 25 controls the switch 23 so that the sensor electrode 22 is in a floating state or a grounded state according to the data to be transmitted. . For example, the CPU 25 places the sensor electrode 22 in a floating state when transmitting data “0”, and places the sensor electrode 22 in a ground state when transmitting data “1”.

  Next, the reception side touch sensor 26 will be described. The reception-side touch sensor 26 is set to either a touch sensor mode that functions as a general touch sensor or a data transmission mode that functions as a data transmission member. In the present embodiment, the reception-side touch sensor 26 illustrated in FIG. 2 includes four sensor electrodes 27, four detection circuits 28 connected to the sensor electrodes 27, and a CPU 29.

  Each sensor electrode 27 conducts electric charge when touched by a finger or a ground conductor. Further, when the reception side touch sensor 26 receives data from the transmission side touch sensor 21, the four sensor electrodes 27 are coupled to the four sensor electrodes 22 of the transmission side touch sensor 21, respectively. The detection circuit 28 is connected to each of the sensor electrodes 27, detects a change in capacitance, and transmits it to the CPU 29. The CPU 29 sets the receiving side touch sensor 26 to either the touch sensor mode or the data transmission mode based on an instruction from the user.

  Here, when the touch sensor mode is set in the reception-side touch sensor 26, the CPU 29 uses the detection circuit 28 to constantly monitor whether or not the capacitance has changed. The detection circuit 28 constantly monitors the change in capacitance, so that the reception side touch sensor 26 functions as a general touch sensor.

  On the other hand, when the data transmission mode is set in the reception-side touch sensor 26, the CPU 29 controls the detection circuit 28 to monitor whether the capacitance has changed for a predetermined time. If no change in capacitance is detected even after a predetermined time has elapsed, it is determined that the sensor electrode 22 of the transmission side touch sensor 21 is in a floating state, and it is determined that data “0” has been transmitted. On the other hand, if a capacitance change is detected before the predetermined time has elapsed, it is determined that the sensor electrode 22 is grounded, and it is determined that data “1” has been transmitted.

  As described above, in the present embodiment, the transmission-side touch sensor 21 places the electrode sensor electrode 22 in a floating state when transmitting “0” data, and the electrode sensor electrode 22 when transmitting “1” data. To ground. On the other hand, in the data transmission mode, the reception-side touch sensor 26 determines that “0” data has been transmitted when no change in capacity is detected, and determines that “1” data has been transmitted when a change in capacity has been detected. To do.

  Here, since the touch sensors 21 and 26 according to the present embodiment include the four sensor electrodes 22 and 27, respectively, 4-bit data can be transmitted. For example, when the sensor electrode 22 is in a predetermined order (grounded state, floating state, grounded state, floating state), the reception-side touch sensor 26 recognizes that the data (1010) has been transmitted. The number of sensor electrodes 22 and 27 is not limited to four. By increasing the number of sensor electrodes 22 and 27, data of 8 bits, 26 bits, or more can be transmitted. The number of data to be transmitted is not limited to a multiple of 4.

  Furthermore, by detecting the grounding state / floating state of the sensor electrode 22 every predetermined time, a large amount of data can be transmitted continuously. In general, the detection circuit 28 is formed in the driver IC, and the CPU 29 calculates the capacitance distribution in the touch panel surface in the driver IC. In this case, the amount of information can be increased by finely setting a threshold for the capacity distribution. For example, when the detected capacity distribution exceeds 80% of the maximum value of the capacity distribution, it can be recognized that the data of (1111) is transmitted, and when it is 60% or more and less than 80%, the data of (1100) is transmitted.

  Alternatively, the reception-side touch sensor 26 may hold a predetermined threshold value, and if the detection circuit 28 detects a capacitance change larger than the threshold value, it may be determined that data “1” has been transmitted. The threshold value is desirably set to a value that can accurately determine whether or not the sensor electrode 22 of the transmission side touch sensor 21 is grounded.

  As described above, in the touch sensor according to the present embodiment, the transmission-side touch sensor 21 includes the electrode-side terminal 23a, the circuit-side terminal 23b, the floating terminal 23c, and the ground terminal 23d based on the control from the CPU 25. What is necessary is just to add the switch 23 connected to either of these. On the other hand, it is only necessary to add a process for switching the mode to the reception-side touch sensor 26, and it is not necessary to add a new sensor or the like. Therefore, an increase in size and cost can be avoided, and a touch sensor having both a touch sensor function and an information transmission function can be provided.

  In the above description, an example in which the switch 23 is not disposed on the reception-side touch sensor 26 is shown, but a configuration similar to that of the transmission-side touch sensor 21 may be used.

(Third embodiment)
A third embodiment will be described. In the present embodiment, a touch panel including the touch sensor described in the first embodiment will be described.

  FIG. 3A shows a side view of the touch panel according to the present embodiment, and FIG. 3B shows a front view thereof. In FIG. 3A, the touch panel has a touch panel unit 31 disposed on a display panel unit 30. Since the display panel unit 30 can use a general LCD (Liquid Crystal Display) or the like, detailed description is omitted. Hereinafter, the display panel unit 30 is simply referred to as the display unit 30 and the touch panel unit 31 is referred to as the touch panel 31.

  In FIG. 3A, the touch panel 31 has an X-axis sensor electrode 33 and a Y-axis sensor electrode 34 disposed on a base material 32. A resin sheet 35 is disposed between the X-axis sensor electrode 33 and the Y-axis sensor electrode 34 to insulate them. A protective screen 36 is disposed on the X-axis sensor electrode 33 and the Y-axis sensor electrode 34 to protect them.

  Here, the X-axis sensor electrode 33 and the Y-axis sensor electrode 34 are formed of transparent electrodes. Moreover, the base material 32, the resin sheet 35, and the protective screen 36 are formed of a transparent member. For example, the base material 32 and the protective screen 36 can be formed of transparent glass or a transparent resin film. A resin film can be used instead of the resin sheet 35.

  By forming each member of the touch panel 31 with a transparent member, the user can visually recognize the display on the display panel 30 via the touch panel 31. When the user confirms the display on the display panel 30 and touches a desired position, the touch position is detected by the touch panel 31.

  FIG. 3B will be described. In the touch panel 31, a plurality of diamond-shaped electrodes are arranged in a grid pattern. An X-axis sensor electrode 33 is formed by connecting the electrodes in the vertical direction. Further, the Y-axis sensor electrode 34 is formed by connecting the electrodes in the lateral direction. In FIG. 3B, six X-axis sensor electrodes 33 and ten Y-axis sensor electrodes 34 are formed on the touch panel 31. The shape of the electrode is not limited to a diamond shape. In addition, the number of sensor electrodes can be appropriately determined according to the screen size, resolution, and the like of the display panel 30.

  In FIG. 3B, each X-axis sensor electrode 33 is connected to a switch 37a. When the touch panel 31 functions as a touch sensor, the switch 37a is closed to detect a touch of a finger or a ground conductor, and connects the X-axis sensor electrode 33 to the detection circuit 39. On the other hand, when the touch panel 31 functions as a data transmission member, the switch 37a is opened to prevent unnecessary capacitive coupling, and causes the X-axis sensor electrode 33 to float.

  The Y-axis sensor electrode 34 is connected to the switch 37b and the switch 37c, respectively. When the touch panel 31 functions as a touch sensor, the switch 37b is closed to detect a touch of a finger or a ground conductor, and the Y-axis sensor electrode 34 is connected to the detection circuit 39. On the other hand, the switch 37c is opened. Further, when the touch panel 31 functions as a data transmission member, the switch 37b is opened. On the other hand, the switch 37c is closed, and the Y-axis sensor electrode 34 is connected to the switch 38. Here, the switches 37a, 37b and 37c correspond to the selection means in the claims.

  The switch 38 places the Y-axis sensor electrode 34 in either a floating state or a grounded state when the touch panel 31 functions as a data transmission member. For example, the switch 38 is closed when data “1” is transmitted, and the Y-axis sensor electrode 34 is grounded. Further, when “0” data is transmitted, it is opened, and the Y-axis sensor electrode 34 is brought into a floating state. Here, the switch 38 corresponds to the state setting means in the claims.

  FIG. 4 shows a state where data is transmitted using the touch panel described above. As shown in FIG. 4, when data is transmitted between two touch panels, the receiving touch panel protective screen 36 and the transmitting touch panel protective screen 36 are arranged to face each other, and the data transmission mode is set. . When the data transmission mode is set, the transmission-side touch panel opens the switches 37a and 37b and closes the switch 37c. Further, the switch 38 is opened or closed according to the data to be transmitted. On the other hand, the receiving-side touch panel monitors the capacitance change of the Y-axis sensor electrode 34 for a predetermined time, and determines that “0” or “1” data is transmitted depending on the presence or absence of the capacitance change.

  As described above, the touch panel 31 according to the present embodiment adds the switches 37 and 38 to the normal touch panel and controls the switches 37 and 38. There is no need to install a short-range communication module or a circuit for changing the electrostatic field strength. Therefore, it is possible to avoid an increase in the size and cost of the device, and to provide both a touch sensor function and a data transmission function. A touch panel having a function can be provided.

  In addition, in order to detect a capacitance change efficiently, it is desirable that sensor electrodes used for data transmission are arranged close to each other. In this embodiment, since the Y-axis sensor electrode 34 extending in the lateral direction is used for data transmission, the Y-axis sensor electrode 34 is arranged on the surface side (protective screen 36 side) of the X-axis sensor electrode 33 in FIG.

(Fourth embodiment)
A fourth embodiment of the present invention will be described. In the present embodiment, a mutual capacitance detection type touch sensor in which an AC drive and a sensing line are separately provided is used. FIG. 5 shows a top view of the touch panel according to the present embodiment. In FIG. 5, the touch panel 51 detects a touch and transmits data to the touch panel 52. Here, a signal flow when the touch panel 51 transmits data to the touch panel 52 is indicated by a solid line, and a signal flow when the touch panel 51 detects a touch is indicated by a dotted line. Hereinafter, although the touch panel 51 is demonstrated, the touch panel 52 is comprised similarly.

  In FIG. 5, the touch panel 51 includes a high-pass filter HPF (High-pass filter) 53, a low-pass filter LPF (Low-pass filter) 54, and an element 55. The HPF 53 and the LPF 54 function as switches that switch the touch panel 51 to the touch sensor mode or the data transmission mode. Here, the HPF 53 and the LPF 54 can be configured by a capacitor, a coil, or the like. The element 55 functions as a switch that switches between the floating state and the ground state of the electrode of the touch panel 51. Here, as the element 55, a transistor, an antifuse that can be set conductive / non-conductive by prior writing, or the like can be used.

  In the present embodiment, the touch panel 51 uses different scan clock frequencies in the touch sensor mode and the data transmission mode. For example, the scan clock frequency f1 is used in the data transmission mode, and the scan clock frequency f2 sufficiently higher than f1 is used in the touch sensor mode. The HPF 53 of the touch panel 51 is adjusted so that it passes f2 and does not pass f1, while the LPF 54 is adjusted so that it passes f1 and does not pass f2.

  That is, as shown in FIG. 5, a touch on the position 57 of the touch panel 51 is detected as a signal f <b> 2 indicated by a dotted line, and is detected by the detection circuit 56 through the HPF 53. On the other hand, a signal generated by setting the conduction / non-conduction of the element 55 based on the data to be transmitted passes through the LPF 54 and is transmitted to the touch panel 52 as a signal (f1) indicated by a solid line.

  As described above, the scan clock frequency is changed between the touch sensor mode and the data transmission mode, and only the signal (f2) in the touch sensor mode is input to the detection circuit 56 and only the signal (f1) in the data transmission mode is input to the element 55. In this case, the touch sensor does not need to be provided with a mechanical switch. Furthermore, when a filter or an antifuse is used for selecting a signal, the filter and the antifuse do not require a power source. Therefore, data can be transmitted to the receiving side touch panel when the power source is not turned on. .

  Therefore, the touch sensor can be further miniaturized and an information transmission unit that does not require power-on can be provided.

  The arrangement of the HPF 53 and the LPF 54 is not limited to FIG. In the case of f1 >> f2, the HPF 53 and the LPF 54 may be interchanged.

  Furthermore, by mounting a frequency counter between the LPF 54 and the element 55 in the touch panel 51, the reliability of data transmission can be improved. That is, in the touch sensor mode, an alternating current flows in the circuit via the Y-axis sensor electrode 43, and the frequency of the alternating current is measured using the frequency counter. Then, the reception-side touch panel 52 changes the scan lock frequency when data is received by detecting a change in capacity. Then, when the frequency counter of the touch panel 51 detects the change in the frequency, the touch panel 51 recognizes that the data transmission is successful. By confirming the success or failure of data transmission, the reliability of data transmission is improved. Furthermore, when data is repeatedly transmitted, the data delimiter can be clarified.

DESCRIPTION OF SYMBOLS 10 Touch sensor 11 Electrode 12 Detection means 13 Setting means 21 Transmission side touch sensor 22 Sensor electrode 23 Switch 23a Electrode side terminal 23b Circuit side terminal 23c Floating terminal 23d Grounding terminal 24 Detection circuit 25 CPU
26 Receiving side touch sensor 27 Sensor electrode 28 Detection circuit 29 CPU
30 Display panel 31 Touch panel 32 Base material 33 X-axis sensor electrode 34 Y-axis sensor electrode 35 Resin sheet 36 Protective screen 37a, 37b, 37c Switch 38 Switch 39 Detection circuit 51, 52 Touch panel 53 HPF
54 LPF
55 elements 56 detection circuit 61 display panel 62 camera 63, 64 near field communication module

Claims (6)

Electrodes,
Detecting means for detecting a change in capacitance of the electrode;
Setting means for connecting the electrode to the detection means when detecting a touch, setting the electrode to a ground state when transmitting first information, and setting the electrode to a floating state when transmitting second information When,
A touch sensor comprising: The setting means connects the electrode to the detection means when detecting the touch, and sets the electrode to the detection means when the touch is detected, and sets the electrode when the information is transmitted. The touch sensor according to claim 1, further comprising selection means connected to the state setting means. Information on the capacitance is sent from the electrode to the selection means using a first frequency for touch detection and a second frequency for information transmission,
The selection means includes a first filter that passes the first frequency and does not pass the second frequency, and a second filter that passes the second frequency and does not pass the first frequency. Item 3. The touch sensor according to item 2. The touch sensor according to claim 2 or 3, wherein the state setting means is a transistor or an antifuse in which conduction / non-conduction is set in advance. A display panel unit;
A touch panel unit disposed on the display panel;
A touch panel comprising:
The touch panel unit is a touch panel in which the touch sensor according to any one of claims 1 to 4 is formed of a transparent member. When detecting a touch, the change in the capacitance of the electrode is monitored, when transmitting the first information, the electrode is grounded, and when transmitting the second information, the electrode is floated. An information transmission method using a touch sensor.

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