JP2013105378A - Sensor sheet, detection circuit, touch panel device, and tablet input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor sheet, a detection circuit, a touch panel device, and a tablet input device that have high detection sensitivity and can evenly illuminate the whole surface.SOLUTION: A sensor sheet includes: a holding body 4; three or more detection electrodes 7 disposed on only one surface of the holding body 4 in the thickness direction of the holding body 4 and away from one another; plural relay electrodes 10 disposed on a surface opposite to the one surface so as to overlap with the three or more detection electrodes 7 when viewed in the thickness direction of the holding body 4; and wiring 9 disposed on the opposite surface, electrically connected to each of the relay electrodes, and electrically connected to a detection circuit. One of the plural relay electrodes 10 faces one of the three or more detection electrodes 7 and is disposed in an area outside borderlines of other detection electrodes 7 adjacent to the one detection electrode 7 when viewed in the thickness direction of the holding body 4.

Description

  The present invention relates to a sensor sheet, a detection circuit, a touch panel device, and a tablet input device.

2. Description of the Related Art Conventionally, an input device for inputting to an electronic device has a panel surface for contacting a stylus pen or a user's finger (hereinafter referred to as “input body”). 2. Description of the Related Art There is known a touch panel device that detects the position of an input body when the input body comes into contact with a surface and outputs the position to the electronic apparatus as coordinate information of the input body.
In recent years, a touch panel device including a multi-touch type sensor sheet that detects a position where an input body is in contact with a plurality of positions when the input body is in contact with each other has become widespread.

  For example, Patent Document 1 describes a touch panel including a plurality of sensor electrodes (transparent electrodes). In the touch panel described in Patent Document 1, each sensor electrode is individually provided with a wiring for connecting to a touch panel controller for detecting the capacitance between each sensor electrode and the input body. The wiring provided in the touch panel described in Patent Document 1 is routed so as to pass between the plurality of sensor electrodes.

JP 2011-170784 A

  The wiring of the touch panel described in Patent Document 1 has a linear shape with a small area facing the input body, and when the input body is close to the wiring, the input body is close to the sensor electrode connected to the wiring. The possibility of false detection is kept low. However, if the wiring is made thinner, the resistance of the wiring becomes higher. Further, if the wiring is made of metal for the purpose of reducing the resistance value of the wiring, when the entire surface of the touch panel is illuminated, a dark part is generated due to the illumination light being blocked by the metal wiring, resulting in uneven brightness. .

  The present invention has been made in view of the above-described circumstances, and an object thereof is a sensor sheet, a detection circuit, a touch panel device, and a tablet input device that have high detection sensitivity and can uniformly illuminate the entire surface. Is to provide.

In order to solve the above problems, the present invention proposes the following means.
The sensor sheet of the present invention is a sensor sheet for an input device connected to a detection circuit that detects the proximity of the input body and the position of the input body in proximity, and the thickness of the holding body and the holding body Three or more detection electrodes that are spaced apart from each other on only one surface in the vertical direction and change in capacitance between the input body and the input body, and the thickness of the holding body A plurality of relay electrodes arranged on the surface opposite to the one so as to overlap the three or more detection electrodes when viewed from the side, and wiring disposed on the surface opposite to the one. Wiring connected to each of the relay electrodes and electrically connected to the detection circuit, wherein one relay electrode of the plurality of relay electrodes includes the three or more detection electrodes. One of the electrodes facing the detection electrode and the holding electrode. When viewed from the thickness direction of the body, a sensor sheet, characterized in that arranged in the outer region of the contour line of the other detection electrodes adjacent to the one detection electrode.

Moreover, it is preferable that the said holding body has a light transmission part which has a light transmittance, and radiate | emits illumination light to the thickness direction of the said holding body.
The three or more detection electrodes are preferably arranged in a triangular lattice shape.
The three or more detection electrodes preferably have a regular polygonal shape when viewed from the thickness direction of the holding body.

  Further, four or more detection electrodes may be provided and arranged in a square lattice shape.

  The detection circuit of the present invention is a detection circuit for an input device connected to the sensor sheet of the present invention, and is a detection unit that is electrically connected to the plurality of wires and detects a change in capacitance, A threshold value of capacitance change amount for the plurality of detection electrodes is set electrically connected to the detection unit, and the change amount exceeding the threshold value is detected among the plurality of detection electrodes. The detection electrodes that are adjacent to each other as one detection electrode group, and the grouping unit that groups the plurality of detection electrodes into one or more detection electrode groups, and the grouping unit For each of the detection electrode groups, three or more detection electrodes are extracted in descending order of the change amount for each of the detection electrode groups, and based on the change amount and the coordinates in the extracted detection electrodes. The holding body A position calculation unit for calculating the coordinates of the input body on the top, and a change in electrostatic capacitance between the input body and the detection electrode when the input body approaches the detection electrode is relayed It is a detection circuit characterized by detecting through an electrode.

  Further, the touch panel device of the present invention includes the detection circuit of the present invention, the sensor sheet according to any one of claims 1 to 5 connected to the detection circuit, and the sensor in the thickness direction of the sensor sheet. A touch panel device comprising: a display device provided to overlap with a sheet.

  Moreover, the tablet input device of this invention is equipped with the detection circuit of this invention, and the sensor sheet | seat as described in any one of Claim 1 to 5 connected to the said detection circuit, The tablet input characterized by the above-mentioned. Device.

According to the sensor sheet and the touch panel device of the present invention, the entire surface can be illuminated uniformly.
Further, according to the detection circuit of the present invention, a change in capacitance between the detection electrode and the input body can be detected via the relay electrode.

It is a top view of the tablet input device of a 1st embodiment of the present invention. It is sectional drawing in the A1-A1 line | wire of FIG. It is sectional drawing in the A2-A2 line | wire of FIG. It is sectional drawing in the A3-A3 line | wire of FIG. It is a block diagram which shows the structure of the tablet input device. It is a figure for demonstrating operation | movement of the tablet input device. It is a flowchart which shows operation | movement of the tablet input device and a detection circuit. It is a figure for demonstrating the effect | action of the tablet input device. It is a schematic diagram for demonstrating the modification of the tablet input device of the embodiment. It is sectional drawing which shows the structure of a part of touchscreen apparatus of 2nd Embodiment of this invention.

(First embodiment)
A sensor sheet 3 and a tablet input device 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of the tablet input device of this embodiment. 2 is a cross-sectional view taken along line A1-A1 of FIG. 3 is a cross-sectional view taken along line A2-A2 of FIG. 4 is a cross-sectional view taken along line A3-A3 of FIG. FIG. 5 is a block diagram showing the configuration of the tablet input device.

  As shown in FIGS. 1 and 2, the tablet input device 1 according to the present embodiment detects the proximity of the input body 100 (see FIG. 2) and the position of the input body 100 that is close to each other, and the input body 100. The input operation by is accepted. The input body 100 in the tablet input device 1 may be a human finger, for example. The input body 100 is not limited to a human finger. As the input body 100, a stylus pen or other conductor can be appropriately employed.

As shown in FIG. 1, the tablet input device 1 of this embodiment includes a panel unit 2 and a detection circuit 20 electrically connected to the panel unit 2.
As shown in FIG. 2, the panel unit 2 includes a sensor sheet 3 and a decorative layer 13 laminated on the sensor sheet 3. In the following description, the side with the sensor sheet 3 is set as the bottom, and the side with the decoration layer 13 is set as the top.

The sensor sheet 3 includes a holding body 4, a detection layer 6, and a relay layer 9.
As shown in FIGS. 3 and 4, the holding body 4 is a thin plate-like, film-like, or film-like insulating member made of resin. In the present embodiment, the holding body 4 is made of a highly transparent silicone rubber and has light transmittance. In this embodiment, the thickness dimension of the holding body 4 is 0.2 mm. A light source 5 that emits illumination light L can be attached to the holder 4. As the light source 5 attached to the holding body 4, for example, an LED, a cold cathode tube, or the like can be appropriately selected and employed. Furthermore, the illumination light L emitted from the light source 5 spreads into the holding body 4 through the inside of the holding body 4, and the surface of the holding body 4 on which at least the detection electrode 7 is disposed (hereinafter referred to as “light emitting portion 4 a”). The light is emitted from. The light exit portion 4a may be formed with a light exit pattern (not shown) for emitting light emitted from the light source 5 by, for example, printing.

  As shown in FIG. 2, the detection layer 6 includes a plurality of detection electrodes 7 having optical transparency, and a detection-side support base 8 on which the plurality of detection electrodes 7 are fixed.

  As shown in FIGS. 2 and 3, three or more detection electrodes 7 are arranged apart from each other on one surface in the thickness direction of the holding body 4. In the present embodiment, the detection electrode 7 is formed only on the surface directed toward the decorative layer 13 in the thickness direction of the holding body 4. The shape of each of the plurality of detection electrodes 7 is a regular hexagon when viewed from the thickness direction of the holding body 4. At least three detection electrodes 7 are arranged. In this embodiment, 67 detection electrodes 7 are provided on the holding body 4. In addition, if the number of the detection electrodes 7 is three or more, it can be appropriately increased or decreased according to the size of the panel unit 2. In the present embodiment, the plurality of detection electrodes 7 are arranged in a triangular lattice pattern on the surface of the holding body 4, and each of the detection electrodes 7 has three detection electrodes 7 whose centers O1 of the detection electrodes 7 are adjacent to each other. Are arranged so as to form vertices of an equilateral triangle.

  Moreover, as a material of the light-transmitting detection electrode 7, for example, a transparent conductive resin material can be employed. Specifically, as the material of the detection electrode 7, it is possible to adopt SEPLEGYDA (registered trademark), indium tin oxide (ITO) made of Shin-Etsu polymer using a polythiophene-based conductive polymer.

  As shown in FIG. 2, the detection-side support base 8 is a plate-like, sheet-like, film-like, or film-like member having optical transparency, and each detection electrode 7 is fixed to the lower surface. It is arranged. In this embodiment, after each detection electrode 7 is patterned on the detection-side support base material 8, the detection layer 6 and the holding body 4 are made of an adhesive or an adhesive so that each detection electrode 7 is in contact with the holding body 4. It is pasted together.

In the present embodiment, both the holding body 4 and the detection layer 6 are light transmissive. For this reason, when the illumination light L is irradiated from the light source 5 into the holding body 4, the entire surface of the sensor sheet 3 is illuminated on the light output part 4a side. That is, the holding body 4 in the present embodiment functions as a light guide in the sensor sheet 3.
In addition, when it is not necessary to illuminate the sensor sheet 3, the holding body 4, the detection electrode 7, and the detection side support base material 8 do not need to have light transmittance. Further, when it is not necessary to illuminate the sensor sheet 3, a light-impermeable material such as a cured metal paste, carbon, and metal foil can be used as the material of the detection electrode 7.

  As shown in FIGS. 2 and 4, the relay layer 9 includes a plurality of relay electrodes 10, a plurality of wirings 11 connected to each relay electrode 10, and a relay side on which the relay electrodes 10 and the wirings 11 are fixed. And a support base 12.

  The relay electrode 10 is provided on the surface of the holding body 4 opposite to the surface on which the detection electrode 7 is disposed. The same number of relay electrodes 10 as the plurality of detection electrodes 7 are provided. Further, each relay electrode 10 is disposed to face each detection electrode 7. Further, one relay electrode 10 of the plurality of relay electrodes 10 is another detection adjacent to one detection electrode 7 facing the one relay electrode 10 when viewed from the thickness direction of the holding body 4. It is arranged in the outer region of the contour line of the electrode 7. In this embodiment, when viewed from the thickness direction of the holding body 4, one relay electrode 10 is accommodated in the inner region of the contour line of one detection electrode 7. The shape of the relay electrode 10 when viewed from the thickness direction of the holder 4 is circular. In addition, the shape of the relay electrode 10 when viewed from the thickness direction of the holding body 4 may be similar to that of the detection electrode 7. The material of the relay electrode 10 is preferably a material with low electrical resistance. For example, the material of the relay electrode 10 may be a conductor layer obtained by curing a metal particle paste screen-printed on the holder 4, a metal thin film formed on the holder 4 by sputtering or the like, or an adhesive or an adhesive. Examples thereof include a metal sheet attached to the holding body 4. Moreover, the relay electrode 10 may have light transmittance. As a material having optical transparency, for example, SEPLEGYDA (registered trademark) manufactured by Shin-Etsu Polymer, indium tin oxide (ITO), or the like can be used.

  As shown in FIG. 4, one end of the wiring 11 is connected to each of the relay electrodes 10, and one of the both sides of the holding body 4 in the thickness direction along the surface on which the relay electrode 10 is disposed. Extending toward the drawer portion 12a (described later). Further, the wirings 11 are arranged at equal intervals in a later-described drawer portion 12a. In the present embodiment, the wiring 11 may have a light transmission property or may not have a light transmission property. The specific material of the wiring 11 may be appropriately selected from the materials exemplified as the material of the relay electrode 10 and employed. The wire 11 preferably has a narrow line width. By narrowing the line width of the wiring 11, the facing area between the wiring 11 and the input body 100 can be reduced, and noise received when the input body 100 is close to the wiring 11 can be suppressed low.

As shown in FIGS. 2 and 4, the relay side support base 12 is a member formed in a plate shape, a sheet shape, a film shape, or a film shape, and the relay electrode 10 and the wiring 11 are formed on the upper surface. Yes. The relay-side support base 12 is formed with a lead-out portion 12a for drawing out the wiring 11, and can be connected to the detection circuit 20 at the lead-out portion 12a. The lead portions 12 a are provided at each of the four corners of the relay side support base 12. Thereby, variation in the length of the wiring 11 can be reduced, and signal delay due to the difference in the length of the wiring 11 and mixing of noise due to the length of the wiring 11 being increased can be reduced. In the present embodiment, the leading end of the lead-out portion 12a is formed so as to be connected to a ZIF socket (Zero Insertion Force socket), and each wiring 11 can be detachably connected to the detection circuit 20. .
Moreover, as the relay side support base material 12, PCB (Printed Circuit Board) can also be adopted. In this case, a detection circuit 20 described later can be mounted on the relay-side support base 12.

  The decorative layer 13 (see FIG. 2) is a layer formed of a light-transmitting resin, glass, or a composite material thereof, and has characters, figures, symbols, and other patterns formed thereon. The decorative layer 13 can be formed by printing, for example. In addition, the decorative layer 13 may be formed with an uneven shape. As an example of the concavo-convex shape, a concavo-convex for allowing the user to recognize the home position in the tablet input device 1 by tactile sense, a frame for allowing the user to recognize the input possible range by tactile sense, or Braille can be provided. As a method of providing irregularities on the decorative layer 13, printing, molding using various molding dies, or the like can be used. Further, the decorative layer 13 can also function as a layer for protecting the sensor sheet 3 from an external force transmitted to the sensor sheet 3 or moisture entering the sensor sheet 3.

  Next, the configuration of the detection circuit 20 will be described together with the processing performed by the detection circuit 20. FIG. 6 is a diagram for explaining the operation of the tablet input device according to the present embodiment. FIG. 7 is a flowchart showing operations of the tablet input device and the detection circuit. FIG. 8 is a diagram for explaining the operation of the tablet input device.

  As shown in FIG. 1, the detection circuit 20 is connected to the drawer portion 12 a in the sensor sheet 3. As illustrated in FIG. 5, the detection circuit 20 includes a detection unit 21, a grouping unit 22, a position calculation unit 23, and an output unit 24.

  When the sensor sheet 3 and the detection circuit 20 are connected, the detection unit 21 is electrically connected to each relay electrode 10 formed on the sensor sheet 3 via the wiring 11. In the detection unit 21, the time width for performing the detection operation on each relay electrode 10 and the order in which the detection operation is performed on the plurality of relay electrodes 10 are determined. As a result, the detection unit 21 can sequentially detect the plurality of relay electrodes 10 with a predetermined time width, and can receive a signal indicating the amount of change in capacitance from each of the plurality of relay electrodes 10. (Step S1 shown in FIG. 7).

  Further, when the detection operation for all the relay electrodes 10 is completed, the detection unit 21 outputs a signal of the detected change in capacitance to the grouping unit 22 in the detected order. The detection unit 21 repeatedly detects a change in capacitance between the detection electrode 7 and the input body 100 via the relay electrode 10, and repeatedly outputs a signal of the detected change in capacitance to the grouping unit 22. It is designed to output. The electrostatic capacitance between the relay electrode 10 and the detection electrode 7 is constant, and the electrostatic capacitance between the detection electrode 7 and the input body 100 changes according to the distance between the detection electrode 7 and the input body 100. For this reason, in this embodiment, the change in the capacitance detected by the detection unit 21 is a change based on the position of the input body 100 with respect to the detection electrode 7.

  The grouping unit 22 is electrically connected to the detection unit 21, and receives the amount of change in capacitance output by the detection unit 21. In addition, the grouping unit 22 is set with a threshold value for determining that the signal is input from the relay electrode 10 when the electrostatic capacitance in each of the plurality of relay electrodes 10 changes more than a certain level.

In the present embodiment, the threshold value set in the grouping unit 22 is such a value that it is determined that at least three detection electrodes 7 are input when the input body 100 is brought into contact with one place on the upper surface of the panel unit 2. Is stipulated. When the signal output from the detection unit 21 to the grouping unit 22 exceeds the threshold value, the grouping unit 22 determines that there is an input to the detection electrode 7. When the amount of change in capacitance at the detection electrode 7 is below the threshold value, the grouping unit 22 determines that there has been no input. The threshold value is appropriately set in consideration of the amount of change in capacitance when the input body 100 is close to the wiring 11.
When the threshold value is set in this way and the grouping unit 22 determines that there has been a change in capacitance exceeding the threshold value, the input by the input body 100 is made to the detection electrode 7. It has been detected.

  Furthermore, the grouping unit 22 stores the positional relationship between each of the plurality of detection electrodes 7. That is, the grouping unit 22 stores the coordinates of the plurality of detection electrodes 7 on the surface of the holding body 4. In this embodiment, the coordinates corresponding to the plurality of detection electrodes 7 are envelopes surrounding the plurality of detection electrodes 7 when viewed from the thickness direction of the panel portion 2 (indicated by a two-dot chain line in FIG. Are defined on the basis of an orthogonal coordinate system with two mutually orthogonal axes extending along the long side and the short side in the rectangular region formed by the portion. The origin in the orthogonal coordinate system can be determined at an appropriate position in the surface direction of the panel unit 2. For example, in the present embodiment, the origin is set at one corner in a rectangular region surrounding all the detection electrodes 7. Further, as the coordinates of the plurality of detection electrodes 7, the coordinates of the center position of each detection electrode 7 when viewed from the thickness direction of the holding body 4 are employed. In the present embodiment, the center position of each detection electrode 7 and the center position of the detection electrode 7 disposed opposite to the detection electrode 7 coincide with each other when viewed from the thickness direction of the holding body 4. ing. Below, as shown in FIG. 6, the long side direction in the said rectangular area is demonstrated as an X-axis direction, and a short side direction is demonstrated as a Y-axis direction.

  In addition, the grouping unit 22 has a change amount greater than or equal to a threshold value among the plurality of detection electrodes 7 based on the coordinates of the detection electrodes 7 stored in the grouping unit 22 and the signal input from the detection unit 21. The detected detection electrodes 7 that are adjacent to each other are extracted. Furthermore, the grouping unit 22 sets one or more detection groups G (detection groups G1, G2, see FIG. 8) by the detection electrodes 7 from which the amount of change equal to or greater than the threshold is detected (step S2 shown in FIG. 7). In addition, the coordinates of the detection electrodes 7 included in each of the detection groups G and the amount of change in the capacitance of these detection electrodes 7 are stored as electromagnetic information.

  As shown in FIG. 8, in this embodiment, when one detection group G is set, the number of detection electrodes 7 included in this detection group G is three or more. Since one relay electrode 10 is disposed opposite to one detection electrode 7, the number of relay electrodes 10 included in the detection group G is the same as the number of detection electrodes 7 included in the detection group G. Further, even when the detection amount of the capacitance change amount exceeds the threshold value, if there is no detection electrode 7 whose capacitance change amount exceeds the threshold value in the adjacent detection electrode 7, one detection is performed. The detection group G by only the electrode 7 is not set. As a result, since a change in capacitance in a narrow range where a change in capacitance occurs only in one detection electrode 7 is not determined as an input, the occurrence of erroneous detection due to noise transmitted to the detection electrode 7 is reduced. be able to. Further, the detection group G is not set only by the two detection electrodes 7 adjacent to each other.

  The information of the detection group G stored in the grouping unit 22 may be all of the detection groups G grouped in the grouping unit 22, and is limited to, for example, 10 groups or less, or 5 groups or less. It may be. This is appropriately increased or decreased in accordance with the number of simultaneous inputs assumed in the tablet input device 1 (for example, touching the upper surface of the panel unit 2 simultaneously with 10 fingers of either hand or any two or three fingers). Can be determined.

  If the number of detection groups G stored in the grouping unit 22 is small, the number of input bodies 100 that can receive simultaneous inputs performed close to the detection electrodes 7 is small, but the entire detection circuit 20 and the detection circuit 20 The processing in the electronic circuit that processes the coordinate information M, which will be described later, output from is reduced. Conversely, if the number of detection groups G stored in the grouping unit 22 is large, the processing in the detection circuit 20 becomes heavy, but the quantity that can accept simultaneous input increases. Note that the number of detection groups G that can be stored in the grouping unit 22 may be set and changed separately after the detection circuit 20 is manufactured.

  The information of the detection group G stored in the grouping unit 22 is updated at regular intervals. For example, the grouping unit 22 updates the information of the detection group G based on the input new change amount each time the change amount of the electrostatic capacitance for all the detection electrodes 7 is input by the detection unit 21. It is like that.

  The position calculation unit 23 is electrically connected to the grouping unit 22 so that the information of the detection group G stored in the grouping unit 22 can be referred to. Further, the position calculation unit 23 ranks the three detection electrodes 7 in the descending order of change amount for each detection group G with respect to each of the detection groups G grouped by the grouping unit 22 (FIG. 7). Step S3) shown in FIG. Furthermore, the position calculation unit 23 stores the coordinates and the amount of change in capacitance of the ranked top three detection electrodes 7. Thereby, three detection electrodes 7 per detection group G extracted and stored in the position calculation unit 23 are set as calculation target detection electrodes T (see FIG. 8) (step S4 shown in FIG. 7). ).

Further, the position calculation unit 23 calculates the coordinates of the input body 100 on the sensor sheet 3 based on the amount of change in capacitance in the calculation target detection electrode T and the coordinates of the calculation target detection electrode T. (Step S5 shown in FIG. 7). In the present embodiment, the position calculation unit 23 also calculates the magnitude of input from the input body 100.
After calculating the coordinates of the input body 100 and the size of the input by the input body 100, the position calculation unit 23 outputs the coordinates and the size of the input to the output unit 24, respectively.

  The calculation of coordinates in the position calculation unit 23 is performed as follows. Hereinafter, calculation of the coordinates of the input body 100 in one detection group G will be described. Calculations for a plurality of detection groups G are performed by sequentially applying a calculation method similar to that for one detection group G.

  First, for the calculation target detection electrode T in one detection group G, the coordinates of the three detection electrodes 7 included in the calculation target detection electrode T are referred to. Hereinafter, the coordinates of the three detection electrodes 7 included in the calculation target detection electrode T are (x1, y1), (x2, y2), and (x3, y3), respectively. Assume that the detected values in the input capacitance change signal are S1, S2, and S3, respectively. At this time, the position calculation unit 23 calculates the coordinates of the input body 100 by substituting the detected values into the arithmetic expressions consisting of the following formulas 1 and 2 in which the respective coordinates in the calculation target detection electrode T are substituted. To do.

X _i in the above equation 1 represents the X coordinate of the input body 100 in the orthogonal coordinate system, and Y _i in the above equation 2 represents the Y coordinate of the input body 100 in the orthogonal coordinate system. Further, Z _i in the above expression 3 indicates a value that the magnitude of the input by the input body 100 is calculated by the position calculation unit 23. Further, _i in X _i , Y _i , and Z _i is a positive integer, and when a plurality of detection groups G are set, a different value is assigned to each detection group G.
According to the above formulas 1 and 2, the weighted average value obtained by weighting the X coordinate and the Y coordinate of the three detection electrodes 7 included in the calculation target detection electrode T with the amount of change in capacitance is the X coordinate of the input body and Y coordinate.
Further, according to the above expression 3, the sum of the detection values S1, S2, and S3 at the calculation target detection electrode T becomes the magnitude of the input by the input body 100.

When the position calculation unit 23 calculates the X coordinate and the Y coordinate of the input body 100, the position calculation unit 23 determines the X coordinate and the Y coordinate and the magnitude of the input by the input body 100 as the coordinates of the input body 100. And it outputs to the output part 24 as a magnitude | size of an input.
In the present embodiment, the position calculation unit 23 repeatedly calculates the coordinates of the input body 100 and the input size every predetermined time, and outputs the calculated coordinates and the input size to the output unit 24, respectively. It has become.

  The output unit 24 is electrically connected to the position calculation unit 23 so that the coordinates of the input body 100 and the input size output from the position calculation unit 23 are input. The output unit 24 can be electrically connected to, for example, another electronic circuit (not shown) connected to the detection circuit 20, and the coordinates calculated by the position calculation unit 23 and the size of the input are expressed as coordinates. Information M (see FIG. 5) is output to another electronic circuit (step S6 shown in FIG. 7).

  The operation of the tablet input device 1 having the above-described configuration will be described focusing on the operation of the sensor sheet 3 and the detection circuit 20.

  When using the tablet input device 1, the user can use the tablet input device 1 while holding the tablet input device 1 in a hand or placing a desk or the like. For example, the user brings the input body 100 (see FIG. 2) into contact with the position A and the position B (see FIG. 8) on the upper surface of the panel unit 2.

  Accordingly, a capacitor is formed between the detection electrode 7 at the position where the input body 100 is close to the sensor body 3 and the input body 100. Then, the capacitance increases in the detection electrode 7 in which the input body 100 is close as compared to before the input body 100 is close. Further, according to the distance between the input body 100 and the detection electrode 7, the detection electrode 7 located closest to the input body 100 has the largest capacitance, and the detection electrode as the distance from the input body 100 increases. The capacitance at 7 is reduced. For this reason, the electrostatic capacitance of the detection electrode 7 differs for each detection electrode 7 at each of the positions A and B where the input body 100 is in contact.

When the capacitance changes in the detection electrode 7 of the sensor sheet 3, a change in capacitance in the detection electrode 7 is detected via the relay electrode 10 in the detection unit 21 (see FIG. 5) of the detection circuit 20. Thereby, in the detection part 21, the variation | change_quantity corresponding to the distance between the input body 100 and the detection electrode 7 is detected.
Further, based on the detection result by the detection unit 21, the relay electrode 10 (the relay electrode 10A shown in FIG. 8) disposed opposite to the detection electrode 7 whose capacitance has changed by a threshold value or more among the detection electrodes 7 close to the input body 100. -1 to 5 and relay electrodes 10B-1 to 6) are stored in the grouping unit 22 as detection groups G, respectively.

  For example, when the input body 100 is brought close to two positions A and B separated from each other in the sensor sheet 3, two detection groups G are extracted by the grouping unit 22 as shown in FIG. It is stored in the grouping unit 22 as another detection group G. For example, when the input body 100 is brought close to two adjacent positions with the input body 100 aligned, one detection group G is extracted by the grouping unit 22 and stored. As described above, in this embodiment, the group of the detection electrodes 7 whose capacitance variation is equal to or greater than the threshold is in a state where the detection electrodes 7 whose capacitance variation is less than the threshold are sandwiched therebetween. Are extracted as a plurality of detection groups G.

  When the detection group G is stored by the grouping unit 22, the position calculation unit 23 calculates the position of the input body 100 in each of the detection groups G based on the above-described Expression 1 and Expression 2, and also by the input body 100. The size of the input is calculated based on Equation 3 above and output to the output unit 24.

  The output unit 24 outputs the coordinate information M to an external electronic circuit, for example. The coordinate information M output to the external electronic circuit is processed by the electronic circuit, a program operating on the electronic circuit, or the like as a command operation for various applications.

  As described above, according to the sensor sheet 3 of the present embodiment, the light-transmitting detection layer 6 is arranged on the light output portion 4 a side of the holder 4, and the detection electrode 7 is arranged on the holder 4. Since the relay electrode 10 and the wiring 11 are arranged on the surface opposite to the formed surface, it is possible to illuminate the entire surface evenly with high detection sensitivity.

  Further, since the detection electrodes 7 are arranged in a triangular lattice shape, the density of the detection electrodes 7 on the surface of the holding body 4 can be increased, and the accuracy of detecting the position of the input body 100 can be increased. In addition, when the contour shape of the detection electrode 7 when viewed from the thickness direction of the sensor sheet 3 is a regular hexagon, the gap between the detection electrodes 7 can be reduced while the shape of the detection electrode 7 is close to a circle. it can.

  Further, according to the detection circuit 20 of the present invention, the grouping unit 22 groups the detection electrodes 7 into the detection group G, and the coordinates of the finger as the input body 100 are set to the position calculation unit 23 for each detection group G. Therefore, the respective positions of the plurality of input bodies 100 can be detected in simultaneous input by simultaneously bringing the plurality of input bodies 100 close to the plurality of positions.

  In addition, since the distance between the input body 100 and the wiring 11 is longer than the distance between the input body 100 and the detection electrode 7, a change in electrostatic capacitance between the input body 100 and the wiring 11 is suppressed to be small. And the possibility of malfunctioning is kept low.

  Further, since it is not necessary to form the wiring 11 or the like (so-called interlayer connection) for electrically connecting the detection electrode 7 and the relay electrode 10, the structure is simple and the manufacture is easy.

  Thus, by providing the sensor sheet 3 and the detection circuit 20 of the present embodiment, it is possible to provide the tablet input device 1 having high detection sensitivity and capable of illuminating the entire surface. Moreover, the tablet input device 1 of this embodiment can respond to simultaneous input (multi-touch) by a plurality of input bodies 100.

(Modification)
Next, a modified example of the sensor sheet of this embodiment will be described. FIG. 9 is a schematic diagram for explaining the configuration of the sensor sheet of the present modification.
The sensor sheet 3 </ b> A in this modification includes a detection electrode 7 </ b> X (see FIG. 9) that is different in arrangement from the detection electrode 7 described in the first embodiment. The detection electrodes 7X in this modification are arranged in a square lattice pattern on one surface of the holding body 4 (see FIG. 2). The shape of each detection electrode when viewed from the thickness direction of the holder 4 is a square shape. In addition, the relay electrodes 10X arranged to face the detection electrodes 7X are also arranged in a square lattice like the detection electrodes 7X.
Specifically, as shown in FIG. 9, the detection electrodes 7 </ b> X are arranged in a square lattice shape whose diagonal lines are parallel to the X axis and the Y axis.

  The detection circuit 20A (see FIG. 1) connected to the sensor sheet 3A having such a configuration is different from the grouping unit 22 of the first embodiment in place of the grouping unit 22 as shown in FIG. It has a grouping unit 22A. The detection group G set in the grouping unit 22A includes four or more detection electrodes 7X, and the grouping unit 22A has the highest detection value of the signal indicating the amount of change in capacitance in each detection group G. Four detection electrodes 7X are selected in order from the one. For example, as shown in FIG. 9, when the input body 100 is brought close to the position C, the four detection electrodes 7 </ b> C- 1 to 4 are selected in order of increasing distance to the position C.

  Further, in the position calculation unit 23, the processing content is different from that in the above-described embodiment, and the coordinates of the four detection electrodes 7X selected by the grouping unit 22A are weighted averages based on the detected capacitance value as in the above-described embodiment. Thus, the coordinates of the input body 100 are calculated.

Even the configuration of the present modification has the same effects as those of the above-described embodiment.
Furthermore, compared to the case where the coordinates of the input body 100 are calculated from the three detection electrodes 7X in the above-described embodiment, the number of detection electrodes to be the calculation target detection electrodes T is one in this modification, so that the detection electrodes The influence of noise transmitted from the outside to 7X can be reduced, and the accuracy of detecting the position of the input body 100 can be further increased.

(Second Embodiment)
Next, a sensor sheet and a touch panel device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 10 is a cross-sectional view showing a partial configuration of the touch panel device of the present embodiment, and is a cross-sectional view showing the same cross section as the A1-A1 line of FIG.

  The touch panel device 30 of the present embodiment detects that the input body 100 (see FIG. 2) has approached and the position of the input body 100 that has approached, and accepts an input operation by the input body 100. An example of the input body 100 in the touch panel device 30 is a human finger. The input body 100 is not limited to a human finger. As the input body 100, a stylus pen or other conductor, a dielectric formed into a rod shape, or the like can be appropriately employed. Furthermore, the touch panel device 30 can be attached to be overlapped with a display device 31 such as a liquid crystal display. In the present embodiment, a case where the display device 31 includes a transmissive liquid crystal panel will be described as an example.

  As shown in FIG. 10, in this embodiment, a sensor sheet 3B having a structure different from that of the sensor sheet 3 described in the first embodiment is provided. The sensor sheet 3B is attached to the back surface side of the display device 31 with, for example, an adhesive 32 so that the user cannot see the sensor sheet 3B. Moreover, the illumination of the sensor sheet 3 described in the first embodiment is also performed in the sensor sheet 3B of the present embodiment, and is used as a backlight in the display device.

  The sensor sheet 3B includes a holding body 4, a detection electrode 7 disposed on the display device side of the holding body 4, and a relay electrode 10 disposed on a surface of the holding body 4 opposite to the surface on which the detection electrode 7 is disposed. And a wiring 11. The positional relationship between each detection electrode 7 and each relay electrode 10 is the same as that in the first embodiment.

In the present embodiment, both the detection electrode 7 and the relay electrode 10 are fixed to the holding body 4. This can be configured, for example, by forming the detection electrode 7 and the relay electrode 10 on the holding body 4 by screen printing or the like. And in this embodiment, the detection side support base material 8 and the relay side support base material 12 which were demonstrated in 1st Embodiment are not provided. For this reason, it is thinner than the sensor sheet 3 described in the first embodiment.
Even if it is such a structure, there exists an effect similar to the sensor sheet 3 demonstrated in 1st Embodiment.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the contour shape of the detection electrode 7 when the detection electrode 7 is viewed from the thickness direction of the sensor sheet 3 is not limited to a hexagon. Further, the shape of the detection electrode 7 is not limited to a regular polygon. For example, the detection electrode 7 may be deformed so that the detection electrode 7 and the wiring 11 do not overlap when viewed from the thickness direction of the sensor sheet 3. Moreover, it is not restricted when all the detection electrodes 7 are the same shape and the same size, and the shapes of the detection electrodes 7 may be different from each other. For example, a region in which the detection electrode 7 having a large area is arranged and a region in which the detection electrode 7 having a small area is arranged are mixed, corresponding to specifications required as resolution for detecting the position of the input body 100. Also good.

  Further, the contour shape of the relay electrode 10 when the relay electrode 10 is viewed from the thickness direction of the sensor sheet 3 is not limited to a circular shape.

  Further, in this embodiment, when the amount of change in capacitance at the detection electrode 7 is equal to the threshold value, the detection electrode 7 is set to be included in the detection group G, but the change in capacitance at the detection electrode 7 is set. When the amount is equal to the threshold value, the detection electrode 7 may be set not to be included in the detection group G.

  Further, in the calculation formula in the position calculation unit 23 of the detection circuit 20, for each X coordinate and Y coordinate of the calculation target detection electrode T, depending on the configuration of the sensor sheet 3 and the processing content in the detection circuit 20. The X-coordinate and Y-coordinate of the calculation target detection electrode T may be converted by multiplying a predetermined coefficient or by separately determining a multiplier according to the configuration of the sensor sheet 3 and the processing content in the detection circuit 20. Thereby, tuning of the detection sensitivity in the tablet input device 1 or the touch panel device 30 can be facilitated.

Moreover, as a material of the holding body 4, an acrylic resin such as polycarbonate, urethane, polymethyl methacrylate resin (PMMA resin), polyethylene terephthalate (PET), or the like can be suitably employed in addition to silicone rubber. Further, the thickness dimension of the holding body 4 may be 0.2 mm or more or less than 0.2 mm.
The holding body 4 is preferably a light guide that guides illumination light when the sensor sheet 3 is illuminated. However, the holding body 4 does not need to be a light guide if illumination is not necessary. When the holder 4 is used as a light guide, for example, silicone rubber can be suitably used as the holder 4. When the holder 4 does not need to be used as a light guide, for example, an adhesive, an adhesive, a double-sided tape having adhesive layers on both sides of the base film, etc. are used as the holder 4 as the detection electrode 7 and the relay electrode 10. It can also be a form interposed between the two.

  Further, the connection between the holding body 4 and the detection circuit 20 is not limited to the ZIF socket in the drawer portion 12a. For example, in the detection circuit 20, a land for contact with a terminal for inputting a signal to the detection unit 21 is formed on the holding body 4, or the detection circuit 20 and the holding body 4 are connected via a rubber connector made of conductive rubber. A land for connection may be formed on the holding body 4. For example, the holding body 4 may be a circuit board.

  Further, as the material of the detection electrode 7, a transparent conductive film containing metal nanowires may be employed. Specific examples of the metal nanowire include silver, gold, copper, and stainless steel. Also,

  As the material of the wiring 11, conductive ink such as ink containing metal foil or metal particles, ink containing thin metal wires, ink containing carbon, ink containing conductive polymer, or the like can be used. The conductive ink can be selected as appropriate based on the resistance value, light transmittance, and elongation during molding.

  In each of the above-described embodiments, when viewed from the thickness direction of the holding body 4, the center position of each detection electrode 7 and the center position of the detection electrode 7 disposed to face the detection electrode 7 are Although the case where it corresponds is shown, the center position of each detection electrode 7 and the center position of the detection electrode 7 arranged facing the detection electrode 7 do not need to match.

  Further, in each of the above-described embodiments, an example is shown in which one relay electrode 10 is disposed opposite to one detection electrode 7, but a plurality of relay electrodes are disposed opposite to one detection electrode 7. It may be.

  Further, the constituent elements shown in the above-described embodiments and modifications can be combined as appropriate.

DESCRIPTION OF SYMBOLS 1 Tablet input device 2 Panel part 3 Sensor sheet 4 Holder 4a Light emission part 5 Light source 6 Detection layer 7 Detection electrode 8 Detection side support base material 9 Relay layer 10 Relay electrode 11 Wiring 12 Relay side support base material 12a Drawer part 13 Decoration Layer 20 Detection circuit 21 Detection unit 22 Grouping unit 23 Position calculation unit 24 Output unit G (G1, G2) Detection group L Illumination light M Coordinate information T Calculation target detection electrode O1 Center 100 Input body

Claims (8)

A sensor sheet for an input device connected to a detection circuit that detects that the input body is close and the position of the input body close to the input body,
Holding body,
Three or more detection electrodes that are spaced apart from each other on only one surface in the thickness direction of the holding body, and whose capacitance changes with the input body when the input body approaches,
A plurality of relay electrodes arranged on a surface opposite to the one so as to overlap the three or more detection electrodes when viewed from the thickness direction of the holding body;
A wiring arranged on the opposite surface and electrically connected to each relay electrode and electrically connected to the detection circuit;
With
One relay electrode of the plurality of relay electrodes faces one detection electrode of the three or more detection electrodes, and when viewed from the thickness direction of the holding body, the one relay electrode A sensor sheet, wherein the sensor sheet is disposed in an outer region of a contour line of another detection electrode adjacent to the detection electrode. The holder is
Light transmissive,
The sensor sheet according to claim 1, further comprising a light output portion that emits illumination light in a thickness direction of the holding body.   The sensor sheet according to claim 1, wherein the three or more detection electrodes are arranged in a triangular lattice shape.   The sensor sheet according to claim 1, wherein the three or more detection electrodes have a regular polygonal shape when viewed from the thickness direction of the holding body.   The sensor sheet according to claim 1, wherein four or more detection electrodes are provided and arranged in a square lattice pattern. A detection circuit for an input device connected to the sensor sheet according to any one of claims 1 to 5,
A detection unit that is electrically connected to the plurality of wirings and detects a change in capacitance;
A threshold value of capacitance change amount for the plurality of detection electrodes is set electrically connected to the detection unit, and the change amount exceeding the threshold value is detected among the plurality of detection electrodes. A detection electrode that is adjacent to each other as one detection electrode group, and a grouping unit that groups the plurality of detection electrodes into one or more detection electrode groups;
For each of the detection electrode groups grouped in the grouping unit, three or more detection electrodes are extracted in descending order of the amount of change for each of the detection electrode groups, and the detection electrodes in the extracted detection electrodes A position calculation unit that calculates the coordinates of the input body on the surface of the holding body based on the amount of change and the coordinates;
With
A detection circuit that detects a change in capacitance between the input body and the detection electrode when the input body approaches the detection electrode via the relay electrode. A detection circuit according to claim 6;
The sensor sheet according to any one of claims 1 to 5 connected to the detection circuit;
A display device provided to overlap the sensor sheet in the thickness direction of the sensor sheet;
A touch panel device comprising: A detection circuit according to claim 6;
The sensor sheet according to any one of claims 1 to 5 connected to the detection circuit;
A tablet input device comprising:

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