JP2012103273A - Pressure-sensitive sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive sensor capable of reducing dispersion in measuring accuracy of external force among products.SOLUTION: This pressure-sensitive sensor includes external force calculation means that retains standardized information Sof "external force-resistance characteristics" that is standardized based on a prescribed mathematical formula, using a resistance value Rwhen applying setting maximum external force Fof a pressure-sensitive ink member that is measured by resistance measuring means, a resistance value Rwithout applying any external force, and a resistance value Rwhen applying external force Fthat is less than the setting maximum external force F; and calculates the external force applied thereto from the resistance value measured by resistance measuring means based on the standardized information Sof the "external force-resistance characteristics". This constitution can reduce the apparent dispersion of the "external force-resistance characteristics" among the products of pressure-sensitive sensor.

Description

  The present invention relates to a sensor that measures an external input, for example, a pressure-sensitive sensor that measures an external force component in a direction perpendicular to the surface among external forces applied to the surface.

  Conventionally, as a pressure-sensitive sensor for measuring an external force (or pressing force) applied to a certain surface, for example, there is a sensor configured as described in Patent Document 1. In the sensor of Patent Document 1, plastic films formed by laminating electrodes and pressure-sensitive ink layers in order are combined with each other with pressure-sensitive ink members facing each other and an insulating layer having an adhesive layer on the front and back surfaces. Is. In addition, since the sensor of Patent Document 1 has irregularities on the surface of the pressure-sensitive ink layer, a gap of a certain distance is formed between the upper and lower pressure-sensitive ink layers, and the upper and lower pressure-sensitive ink layers are in close contact when no pressure is applied. It has a structure that prevents this.

  In the sensor of Patent Document 1 having such a structure, when a pressing force is applied to the upper film, the electrode of the upper film corresponding to a portion to which pressure is applied by bending the upper film is a pressure-sensitive ink layer. It contacts the electrode of the lower film through. Thereby, both electrodes will be in a conductive state. The sensor of Patent Document 1 can measure the pressure applied to the upper film by detecting the conduction state of both electrodes and the change in resistance value according to the pressure applied to the pressure-sensitive ink layer. If the sensor of this patent document 1 is attached to the inside of a vehicle seat, for example, it can be determined whether or not an occupant is sitting on the seat, and the physique of the occupant can be determined from the pressure distribution.

JP 2002-48658 A

  In recent years, in an electronic device having a touch panel, particularly a portable electronic device such as a mobile phone or a game machine, for example, a pressure sensor is required to be mounted on a touch panel of a display as an alternative to a determination button. In the case where the pressure sensor is mounted on such a portable electronic device, it is required to execute the display or function in response to a relatively small force by a human finger.

  However, the sensor disclosed in Patent Document 1 is used, for example, for a purpose of determining whether an occupant is seated on a seat attached to the interior of a vehicle seat, and is intended for portable electronic devices. It cannot be applied to pressure sensors.

  Furthermore, since such a pressure-sensitive sensor employs a structure that obtains continuity between electrodes by physical deformation, it is assumed that there is variation in the measurement accuracy of external force between products. Therefore, when considering application to a portable electronic device, it is necessary to reduce such variation in the measurement accuracy of external force between products.

  In addition, not only pressure-sensitive sensors but also other sensors that measure various external inputs such as light, sound, heat, etc., are caused by variations in measurement accuracy between individuals in such sensors. It is a problem to do.

Accordingly, an object of the present invention is to provide a pressure-sensitive sensor that can solve the above-described problems and can reduce variations in measurement accuracy of external force between products.
Furthermore, another object of the present invention is to provide a pressure-sensitive sensor that can suppress a reduction in the visibility of a display unit of a display device even when mounted on an electronic device having a touch panel.

  In order to achieve the above object, the present invention is configured as follows.

According to the first aspect of the present invention, the first and second substrates disposed to face each other, the pair of electrodes disposed between the first and second substrates, and the pair of electrodes disposed between the pair of electrodes, The external pressure applied in the thickness direction of the first substrate is connected to the conductive pressure-sensitive ink member whose electrical resistance changes and the pair of electrodes, and the external force in the thickness direction of the first substrate is received. Resistance measuring means for measuring the electric resistance value of the pressure-sensitive ink member in contact with the pair of electrodes, and resistance value R _(Fmax) when the set maximum external force F _max of the pressure-sensitive ink member measured by the resistance measuring means is applied. When a resistance value R _(F0) in external force applying no time, by using the resistance value R _(FX) during an external force F _X added less than the set maximum force F _max, the external force is normalized based on the number 1 - resistor Holds standardization information S _(FX) of characteristics, There is provided a pressure-sensitive sensor comprising external force calculation means for calculating an external force added from a resistance value measured by a resistance measurement means based on the external force-resistance characteristic standardization information S _(FX) .
(Equation 1)
S _(FX) = {1 / R _(FX) −1 / R _(F0) } / {1 / R _(Fmax) −1 / R _(F0) }

  According to the second aspect of the present invention, the pair of electrodes is disposed on one of the opposing surfaces of the first and second substrates or separately on both, and at the edge of the first or second substrate. Arranged between the first and second substrates so as to bond the first substrate and the second substrate, and between at least one of the pair of electrodes and the pressure-sensitive ink member. The pressure-sensitive ink member is provided along the edge of the first or second substrate, and an external force is applied in the thickness direction of the first substrate. When the distance between a 1st and 2nd board | substrate reduces, the pressure-sensitive sensor as described in a 1st aspect which contacts a pair of electrodes and makes both conduct | electrically_connect is provided.

  According to the third aspect of the present invention, the pair of electrodes are disposed opposite to the first and second substrates, and the pressure-sensitive ink member is disposed between the pair of electrodes in a state of covering at least one of the pair of electrodes. An adhesive member that is disposed and disposed between the first and second substrates so as to bond the first substrate and the second substrate, and brings the pressure-sensitive ink member into contact with at least one of the pair of electrodes. The pressure-sensitive sensor according to the first aspect is further provided.

  According to a fourth aspect of the present invention, there is provided the pressure-sensitive sensor according to the third aspect, wherein the adhesive member attracts the first substrate and the second substrate to apply an initial load to the pressure-sensitive ink member. .

  According to the fifth aspect of the present invention, at least one of the outer surface of the first substrate and the outer surface of the second substrate is provided with bumps that concentrate and transmit the load to the pressure-sensitive ink member. A pressure-sensitive sensor according to any one of the first to third aspects is provided.

  According to the sixth aspect of the present invention, the load is arranged between at least one of the first substrate and the pressure-sensitive ink member and between the second substrate and the pressure-sensitive ink member, and the load is applied to the pressure-sensitive ink. The pressure-sensitive sensor according to any one of the first aspect and the third to fifth aspects, which is provided with a bump that is transmitted concentratedly on a member.

  According to a seventh aspect of the present invention, there is provided the pressure sensitive sensor according to the sixth aspect, wherein the thickness of the first substrate and the thickness of the second substrate are different.

  According to the eighth aspect of the present invention, the bump is disposed between the first substrate and the pressure-sensitive ink member and between the second substrate and the pressure-sensitive ink member. The pressure-sensitive sensor described in 1. is provided.

According to the ninth aspect of the present invention, there is provided a sensor member that changes its electrical characteristics in response to an external input, an electrical characteristic measuring means having an electrical circuit that measures the electrical characteristic value of the sensor member, The electrical characteristic value C _(Ymax) when the sensor member external input set maximum value Y _{max is} added, the electrical characteristic value C _(Y0) when no external input is added, and the external using the electrical resistance value C _(YX) during the addition of setting the maximum value Y _max of less than the external input Y _X input, normalized based on the number 2 external input - the electrical characteristic normalization information S _{( YX)} is held, and an external input for calculating the external input added to the sensor member from the electrical characteristic value measured by the electrical characteristic measuring means based on the external input-standardized information S _(YX) of the electrical characteristic Input calculation means It comprises, providing a sensor.
(Equation 2)
S _(YX) = {1 / C _(YX) −1 / C _(Y0) } / {1 / C _(Ymax) −1 / C _(Y0) }

According to the present invention, the resistance R in the setting up the external force F _max upon application of the pressure sensitive ink member measured by the resistance measuring means _(Fmax), and the resistance value R _(F0) in external force applying no time, setting up an external force F resistance in the external force F _X added at less than _max by using the R _(FX), normalized based on the number 1 - holding the normalized information S of "external force resistance characteristics" _(FX), "external force - The pressure-sensitive sensor is provided with external force calculation means for calculating an external force added from the resistance value measured by the resistance measurement means based on the normalized information S _(FX) of “resistance characteristics”. As described above, the standardized information S _{(FX) of} “external force-resistance characteristics” standardized by _{Equation 1} is used, so that the apparent variation of “external force-resistance characteristics” among pressure-sensitive sensor products can be reduced. Can be reduced.

  In addition, since the pair of electrodes are arranged in a frame shape along the edge of the first or second substrate, the transmittance of the inner portion surrounded by the frame does not decrease. Therefore, even if it is mounted on an electronic device having a touch panel, it is possible to suppress a reduction in the visibility of the display unit by arranging the display unit of the display device inside the frame. Further, since the pressure-sensitive ink members are scattered along the edge of the first or second substrate, when the same external force is applied to the first substrate, the pressure-sensitive ink member becomes a pair of electrodes. Variation in the area in contact with both is suppressed. Therefore, the measurement accuracy of external force can be improved.

  In addition, in such a pressure-sensitive sensor, a configuration that reduces the apparent variation in “external force-resistance characteristics” between products is a configuration that undergoes a change in the electrical characteristics of the sensor member in response to an external input. It can also be applied to other sensors.

The perspective view of the mobile telephone carrying the touch input device concerning 1st Embodiment of this invention. A1-A1 sectional view of FIG. Perspective view of touch input device Plan view of transparent film for X-axis detection Plan view of transparent film for Y-axis detection Plan view of transparent film for shielding Plan view of pressure-sensitive sensor with touch input device A2-A2 sectional view of FIG. 7 is an exploded perspective view of the pressure sensor shown in FIG. Cross section of gap retaining member Sectional drawing which shows the 1st modification of the pressure sensor with which a touch input device is provided. Sectional drawing which shows the 2nd modification of the pressure sensor with which a touch input device is provided. Sectional drawing which shows the 3rd modification of the pressure sensor with which a touch input device is provided. Sectional drawing which shows the state to which the pressing force of the thickness direction was added to the pressure sensor which concerns on the 3rd modification of FIG. Schematic block diagram showing the configuration of the pressing force detector Schematic plan view of the pressure sensor on the sample Graph of FR characteristics in pressure sensor (5 samples) Graph of standardized FR characteristics of pressure-sensitive sensor (5 samples) The figure which shows arrangement | positioning in the touch input device of the pressure-sensitive sensor concerning 2nd Embodiment of this invention. Exploded view of pressure sensor of second embodiment A3-A3 sectional view of FIG. Enlarged view near the pressure sensor Enlarged view near the pressure sensor Arrangement diagram of a pressure-sensitive sensor according to a third embodiment of the present invention in a touch input device. Exploded view of pressure sensor of third embodiment A4-A4 sectional view in FIG. Sectional drawing of the pressure-sensitive sensor of 3rd Embodiment Sectional drawing of the pressure-sensitive sensor concerning the modification of 3rd Embodiment. Sectional drawing of the pressure-sensitive sensor concerning the modification of 3rd Embodiment. Sectional drawing of the pressure-sensitive sensor concerning the modification of 3rd Embodiment. The schematic block diagram which shows the structure of the sensor concerning 4th Embodiment of this invention. Graph of YC characteristics in sensor of fourth embodiment Graph of standardized YC characteristics in sensor of fourth embodiment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
(Touch input device configuration)
The pressure-sensitive sensor according to the first embodiment of the present invention is configured integrally with a touch panel to constitute a touch input device. In the first embodiment, the touch input device can detect the strength of the pressing force with a pressure sensor in addition to the position detection on the touch panel. The touch input device according to the first embodiment suitably functions as a touch input device for a display of an electronic device having a touch panel, particularly a portable electronic device such as a mobile phone or a game machine. Here, an example will be described in which the touch input device is mounted on a mobile phone which is an example of a portable electronic device.

  FIG. 1 is a perspective view of a mobile phone equipped with a touch input device according to the first embodiment, and FIG. 2 is a cross-sectional view taken along line A1-A1 of FIG. FIG. 3 is a perspective view of the touch input device.

  As shown in FIG. 1, the mobile phone 1 includes a synthetic resin casing 2 having a display window 2 </ b> A formed on the front surface and a display unit 3 </ b> A such as a liquid crystal display or an organic EL. The display device 3, the touch input device 4 fitted in the display window 2 </ b> A, and a plurality of input keys 5 disposed on the front surface of the housing 2 are provided.

  The display window 2 </ b> A of the housing 2 is formed to have a step to allow the touch input device 4 to be fitted. As shown in FIG. 2, an opening 2a is formed on the bottom surface of the display window 2A so that the display 3A of the display device 3 can be seen. The touch input device 4 is disposed on the frame-like portion 2b around the opening 2a and closes the opening 2a.

  Note that the shape and size of the display window 2 </ b> A can be variously changed according to the shape and size of the touch input device 4. The level difference of the display window 2A can be variously changed according to the thickness of the touch input device 4 and the like. The shape and size of the opening 2a of the display window 2A can be variously changed according to the shape and size of the display 3A. Here, the shape of the display window 2A, the opening 2a, the display unit 3A, and the touch input device 4 is rectangular, and the height of the step of the display window 2A is the same between the surface of the housing 2 and the surface of the touch input device 4. It is set to become.

  As illustrated in FIG. 3, the touch input device 4 includes a transparent window portion 4A and a frame-shaped decoration region 4B arranged around the transparent window portion 4A. When the touch input device 4 is disposed in the display window 2A of the casing 2 of the mobile phone, the display unit 3A of the display device 3 can be viewed from the transparent window portion 4A.

  Further, the touch input device 4 is based on a touch operation on the input surface of the touch input device 4, and detects a plane coordinate (XY coordinate) serving as the operation position, and a direction (Z direction) orthogonal to the input surface. And a pressure-sensitive sensor 20 for detecting the strength of the pressing force applied to.

First, the configuration of the touch panel 10 will be described.
The touch panel 10 is, for example, a resistive film type or capacitance type touch panel. Here, an example in which a capacitive touch panel is used as the touch panel 10 will be described. As shown in FIG. 2, the touch panel 10 includes a transparent support substrate 11 serving as an input surface, a decorative film 12, a transparent film for X-axis detection 13, a transparent adhesive layer 14, a transparent film for Y-axis detection 15, The transparent adhesive layer 16, the shielding transparent film 17, the transparent adhesive layer 18, and the hard coat film 19 are sequentially laminated.

  The transparent support substrate 11 is made of a material excellent in transparency, rigidity, and workability, such as glass, polymethyl methacrylate (PMMA) resin, polycarbonate (PC) resin, and the like. A decorative film 12 is attached to the lower surface of the transparent support substrate 11 with a transparent adhesive (not shown).

  The decorative film 12 is formed by applying ink in a frame shape on the peripheral surface of a transparent film. The decoration area 4B of the touch input device 4 is formed by a decoration portion 12a that is a portion to which the ink is applied, and a portion 12b where the decoration portion 12a is not provided becomes a transparent window portion 4A of the touch input device 4. .

  As the ink constituting the decorative portion 12a, polyvinyl chloride resin, polyamide resin, polyester resin, polyacrylic resin, polyurethane resin, polyvinyl acetal resin, polyester urethane resin, cellulose ester resin, alkyd A colored ink containing a resin such as a resin as a binder and an appropriate color pigment or dye as a colorant may be used. Moreover, the decoration part 12a may be formed by printing instead of application | coating. When forming the decoration part 12a by printing, normal printing methods, such as an offset printing method, a gravure printing method, and a screen printing method, can be utilized.

  A transparent film 13 for X-axis detection is attached to the lower surface of the decorative film 12 with a transparent adhesive (not shown). On the lower surface of the X-axis detection transparent film 13, for example, as shown in FIG. 4, upper transparent electrodes 13 a arranged in stripes in one direction, and a predetermined pattern for energizing the outside such as a bus bar and a lead wire The routing circuit 13b is formed. A transparent adhesive layer 14 is disposed on the lower surface of the X-axis detection transparent film 13 so as to cover the upper transparent electrode 13a and the routing circuit 13b, and the transparent adhesive layer 14 causes the Y-axis detection transparent film 15 to be formed. It is stuck. The transparent adhesive layer 14 is, for example, a glue, an adhesive, or a double-sided adhesive tape.

  On the lower surface of the Y-axis detection transparent film 15, as shown in FIG. 5, a lower transparent electrode 15a arranged in a stripe shape in a direction intersecting (for example, orthogonal to) the upper transparent electrode 13a (see FIG. 4), a bus bar, A routing circuit 15b having a predetermined pattern for energizing the outside such as a routing line is formed. A transparent adhesive layer 16 is disposed on the lower surface of the Y-axis detection transparent film 15 so as to cover the lower transparent electrode 15a and the routing circuit 15b, and the transparent film 17 for shielding is attached by the transparent adhesive layer 16. Has been. The transparent adhesive layer 16 is, for example, a glue, an adhesive, or a double-sided adhesive tape.

  On the lower surface of the shielding transparent film 17, as shown in FIG. 6, a rectangular shielding transparent electrode 17a and a routing circuit 17b having a predetermined pattern for connection to the housing 2 (ground) are formed. The shield transparent electrode 17a is formed larger than the display unit 3A of the display device 3, and is disposed at a position where the display unit 3A can be included when viewed from the thickness direction of the touch input device 4. Thus, the shielding transparent electrode 17a functions as a so-called electromagnetic shield that shields the disturbing electromagnetic waves (AC noise) generated from the display device 3. Further, a transparent adhesive layer 18 is disposed on the lower surface of the shield transparent film 17 so as to cover the shield transparent electrode 17a and the routing circuit 17b, and the hard coat film 19 is adhered by the transparent adhesive layer 18. Yes. The transparent adhesive layer 18 is, for example, a glue, an adhesive, or a double-sided adhesive tape.

  The X-axis detection transparent film 13, the Y-axis detection transparent film 15, and the shielding transparent film 17 are made of, for example, polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, or the like. The hard coat film 19 is made of, for example, polyethylene terephthalate (PET) resin or polyimide.

  Each of the transparent electrodes 13a, 15a, and 17a and the routing circuits 13b, 15b, and 17b are made of a transparent conductive film. As a material for the transparent conductive film, a metal oxide such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or ITO, or a conductive polymer thin film can be given. As a method of forming each transparent electrode 13a, 15a, 17a and each routing circuit 13b, 15b, 17b, for example, each transparent film 13, using a vacuum deposition method, sputtering, ion plating, CVD method, roll coater method, etc. There is a method in which an unnecessary portion is removed by etching after a conductive film is formed on the entire surface of 15 and 17. This etching can be performed by forming a resist on a portion to be left as an electrode by a photolithography method, a screen method, or the like and then immersing in an etching solution such as hydrochloric acid. In addition, after the formation of the resist, the etching is performed by spraying an etching solution to remove a portion of the conductive film where the resist is not formed, and then immersing it in a solvent to remove the resist by swelling or dissolving it. Can also be performed. Etching can also be performed with a laser.

(Configuration of pressure sensor)
Next, the configuration of the pressure sensor 20 will be described.
FIG. 7 is a plan view of the pressure-sensitive sensor according to the first embodiment, and FIG. 8 is a cross-sectional view taken along line A2-A2 of FIG. FIG. 9 is an exploded perspective view of the pressure sensor shown in FIG.

  The pressure-sensitive sensor 20 is attached to the lower surface of the hard coat film 19 of the touch panel 10 with an adhesive layer 30 such as glue, adhesive, or double-sided adhesive tape. The pressure-sensitive sensor 20 is formed in a frame shape so as to be concealed by the decorative portion 12a when viewed from above the touch panel 10. Therefore, each member constituting the pressure sensor 20 is not limited to being made of a transparent material, and may be made of a colored material.

  The pressure-sensitive sensor 20 includes an upper film 21 that is an example of a frame-shaped second substrate, and a lower film 22 that is an example of a frame-shaped first substrate that is disposed to face the upper film 21. The pressure-sensitive sensor 20 is attached to the display window 2A by attaching the lower film 22 on the frame-like portion 2b of the display window 2A with, for example, an adhesive (not shown). The thickness dimensions of the upper and lower films 21 and 22 are set to, for example, 25 μm to 100 μm.

  The material of the upper and lower films 21 and 22 is a material that can be used for a flexible substrate, for example, a general-purpose resin such as polyethylene terephthalate, polystyrene resin, polyolefin resin, ABS resin, AS resin, acrylic resin, or AN resin. Can be mentioned. In addition, general-purpose engineering resins such as polystyrene resins, polycarbonate resins, polyacetal resins, polycarbonate-modified polyphenylene ether resins, polybutylene terephthalate resins, ultrahigh molecular weight polyethylene resins, polysulfone resins, polyphenylene sulfide resins, polyphenylene oxide resins, Super engineering resins such as polyarylate resin, polyetherimide resin, polyimide resin, liquid crystal polyester resin, and polyallyl heat-resistant resin can also be used.

  On the surface of the upper film 21 facing the lower film 22, the upper electrode 21a is arranged in a frame shape. On the surface of the lower film 22 facing the upper film 21, the lower electrode 22a is arranged in a frame shape so as to face the upper electrode 21a. Here, the upper electrode 21a and the lower electrode 22a constitute a pair of electrodes. The thickness dimension of the upper and lower electrodes 21a and 22a is set to 10 μm to 20 μm, for example.

  As the material of the upper and lower electrodes 21a and 22a, a metal such as gold, silver, copper, or nickel, or a conductive paste such as carbon can be used. Examples of these forming methods include printing methods such as screen printing, offset printing, gravure printing, and flexographic printing, and a photoresist method. The upper and lower electrodes 21a and 22a can be formed by attaching a metal foil such as copper or gold. Furthermore, the upper and lower electrodes 21a and 22a may be formed by forming an electrode pattern with a resist on an FPC plated with a metal such as copper and etching a portion of the metal foil that is not protected by the resist. it can.

  In the four corner portions of the upper film 21, dot-shaped upper pressure-sensitive ink members 23a are arranged (that is, scattered) so as to partially cover the upper electrode 21a. At the four corners of the lower film 22, dot-like lower pressure-sensitive ink members 23b are disposed (that is, dotted) so as to partially cover the lower electrode 22a and face the upper pressure-sensitive ink member 23a. Yes. The thickness dimension (height from the upper film 21 or the lower film 22) of the upper or lower pressure-sensitive ink members 23a, 23b is larger than the thickness dimension of the upper or lower electrodes 21a, 22a, and is set to 15 μm to 35 μm, for example. Yes.

  The composition constituting the upper and lower pressure-sensitive ink members 23a and 23b is made of a material whose electrical characteristics such as an electrical resistance value change according to an external force. As such a composition, for example, a quantum tunneling composite material available under the trade name “QTC” from Peratech, UK can be used. The upper pressure-sensitive ink member 23a and the lower pressure-sensitive ink member 23b can be disposed on the upper film 21 and the lower film 22 by application. As a method for applying the upper and lower pressure-sensitive ink members 23a and 23b, a printing method such as screen printing, offset printing, gravure printing, or flexographic printing can be used.

  A frame-shaped gap holding member 24 is disposed in a region where the upper film 21 and the lower film 22 are opposed to each other. The gap holding member 24 is an insulating member that has adhesiveness to bond the upper film 21 and the lower film 22 and holds the gap between the upper pressure-sensitive ink member 23a and the lower pressure-sensitive ink member 23b. is there. The gap holding member 24 is, for example, a double-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive 24B such as an acrylic adhesive paste is formed on both surfaces of a core material 24A such as a polyethylene terephthalate film as shown in FIG. The thickness of the gap holding member 24 is set to 50 to 100 μm, for example.

  As shown in FIG. 9, through holes 24 a are respectively provided at the four corners of the gap holding member 24. Each through hole 24a has a width (or inner diameter) larger than that of the upper and lower pressure-sensitive ink members 23a and 23b. For example, the through hole 24a has a width of 3 mm, the upper and lower pressure-sensitive ink members 23a and 23b have a width of 2 mm, and the upper and lower electrodes 21a and 22a have a width of 1 mm. Thereby, the gap holding member 24 and the pressure-sensitive ink members 23a and 23b are prevented from contacting each other. Further, since the gap holding member 24 is disposed between the upper and lower electrodes 21a and 22a at portions other than the through holes 24a, both the electrodes 21a and 22a are disposed at portions other than the portions corresponding to the through holes 24a. It is possible to prevent energization.

  The upper and lower electrodes 21a and 22a are connected to the connector 25. The connector 25 is connected to a pressing force detection unit (not shown) built in the mobile phone 1.

  The pressure-sensitive sensor 20 having such a configuration is in a state where the upper pressure-sensitive ink member 23a and the lower pressure-sensitive ink member 23b are not in contact with each other by the gap holding member 24 during normal time (when no pressure is applied). . In this state, when a pressing force (that is, an external force in the Z direction) is applied to the touch input surface of the touch panel 10 provided on the pressure sensor 20, the upper or lower films 21 and 22 are caused by this pressing force. The upper and lower pressure-sensitive ink members 23a and 23b come into contact with each other by being bent. Thereby, a current flows between the upper electrode 21a and the lower electrode 22a. By detecting the magnitude of this current in the pressing force detection unit, it is possible to detect the pressing force on the input surface to the touch input device 4.

  Further, when the pressing force on the touch input surface to the touch input device 4 is increased, the external force applied to the upper and lower pressure-sensitive ink members 23a and 23b is increased, so that the upper and lower pressure-sensitive ink members 23a and 23b The electrical resistance value becomes smaller. As a result, the current flowing between the upper electrode 21a and the lower electrode 22a increases. By detecting this change in current, the magnitude of the external force applied to the upper or lower pressure-sensitive ink members 23a, 23b can be detected, and the pressing force on the touch input surface to the touch input device 4 is detected. be able to. In the first embodiment, a pressure sensor (or an external force detection device using the pressure sensor) that detects the pressure on the touch input surface by combining the pressure sensor 20 and the pressure detection unit is configured. Has been.

  According to the pressure-sensitive sensor according to the first embodiment, since the upper and lower electrodes 21a and 22a are arranged in a frame shape, the transmittance of the inner portion surrounded by the frame does not decrease. Therefore, even if it is mounted on the mobile phone 1 having the touch panel 10, the visibility of the display unit 3 </ b> A can be prevented from being lowered by arranging the display unit 3 </ b> A of the display device 3 inside the frame. Further, since the pressure-sensitive ink members 23a and 23b are scattered at the respective corner portions of the upper and lower films 21 and 22, when the same pressing force is applied to the upper film 21, the upper or lower pressure-sensitive ink is used. It is possible to suppress variation in the area where the members 23a and 23b are in contact with both the upper and lower electrodes 21a and 22a. Therefore, the pressure measurement accuracy can be improved.

  In addition, this invention is not limited only about the above structures, It can implement in another various aspect. For example, in the first embodiment, both the upper and lower electrodes 21a and 22a are covered with the upper and lower pressure-sensitive ink members 23a and 23b, but the present invention is not limited to this. For example, as shown in FIG. 11, the upper electrode 21a may be covered with the upper pressure-sensitive ink member 23a while the lower electrode 22a may not be covered with the lower pressure-sensitive ink member 23b. That is, at least one of the upper and lower electrodes 21a and 22a may be covered with the pressure-sensitive ink member. In this case, since only one pressure-sensitive ink member is disposed between the upper electrode 21a and the lower electrode 22a, the pressure measurement accuracy is higher than when two pressure-sensitive ink members are disposed. In the case where both the upper and lower electrodes 21a and 22a are covered with the upper and lower pressure-sensitive ink members 23a and 23b as in the first embodiment, the upper and lower electrodes 21a and 22a pass through. A portion exposed in the space of the hole 24a can be reduced. Thereby, problems, such as corrosion of the upper and lower electrodes 21a and 22a, can be suppressed.

  Further, in the first embodiment, the width of each through hole 24a of the gap holding member 24 is formed larger than the width of the upper and lower pressure-sensitive ink members 23a, 23b, but as shown in FIG. You may form smaller than the lower pressure sensitive ink members 23a and 23b. That is, the gap holding member 24 may be configured to contact the periphery of the upper and lower pressure-sensitive ink members 23a and 23b without a gap. As a result, the upper and lower electrodes 21a, 22a can be eliminated from the portions not covered by the upper and lower pressure-sensitive ink members 23a, 23b or the gap holding member 24. That is, it is possible to prevent the upper and lower electrodes 21a and 22a from being exposed in the space of the through hole 24a. Thereby, problems such as corrosion of the upper and lower electrodes 21a and 22a can be eliminated.

  In addition, as shown in FIG. 13, bumps 26 may be stacked as support members on the surface (back surface) of the lower film 22 where the lower electrode 22 a is not provided. Here, the height dimension of the bump 26 is, for example, 50 μm to 200 μm (including the thickness of the adhesive layer when an adhesive layer for bonding the bump to the lower film 22 is present). As a result, as shown in FIG. 14, when a pressing force in the thickness direction is applied to the pressure-sensitive sensor 20, the portion of the pressure-sensitive ink member 23b of the lower film 22 is supported from below and the applied pressing force is dispersed. And can be reliably transmitted as a force used for deformation of the lower film 22. Thereby, the measurement accuracy of pressure can be improved. The bumps 26 are preferably disposed on the back side (directly below) where the pressure-sensitive ink member is provided. Thereby, the upper and lower pressure-sensitive ink members 23a and 23b can be more reliably brought into contact with each other, and the pressure measurement accuracy can be further improved. As shown in FIG. 14, the lower film 22 is more easily deformed and the pressure measurement accuracy is improved when the gap holding member 24 and the upper or lower pressure-sensitive ink members 23a and 23b are not in contact with each other. it can.

  The support member is not limited to the bump 26, and may be a member that is less deformed by pressure. A hemispherical member such as the bump 26 is more effective in transmitting the pressing force. In the above description, the support member is provided on the back surface of the lower film 22. However, the support member may be provided on the back surface (upper surface) of the upper film 21.

  In the first embodiment, the upper or lower pressure-sensitive ink members 23a and 23b are arranged at the corners of the first or lower films 21 and 22. However, the present invention is not limited to this. The upper or lower pressure-sensitive ink members 23 a and 23 b may be arranged so as to be scattered along the edge portions of the upper or lower films 21 and 22. Preferably, the upper or lower pressure-sensitive ink members 23a and 23b are arranged on the left and right sides and at equal intervals.

  In the first embodiment, the decorative film 12 is provided, but the decorative film 12 may not be provided.

(External force-resistance characteristics (FR characteristics) data processing)
Next, the configuration of the pressing force detection unit provided in the pressure sensor and the detection operation of the pressing force (external force) will be described.

  First, as shown in FIG. 15, the pressing force detection unit 50 is electrically connected to the upper and lower electrodes 21a and 22a through the connector 25, and detects the current value flowing through the pressure-sensitive ink members 23a and 23b. A resistance measuring unit (an example of a resistance measuring unit) 51 that measures the electric resistance value of the pressure-sensitive ink members 23a and 23b, and the electric resistance value measured by the resistance measuring unit 51 are added to the touch input surface. And an external force calculating means 52 for calculating the magnitude of the pressing force (external force in the Z direction).

  The external force calculation means 52 has information on “external force-resistance characteristics (hereinafter referred to as“ FR characteristics ”) indicating the relationship between the external force applied to the pressure-sensitive ink members 23a and 23b and the electrical resistance value (hereinafter referred to as“ FR characteristics ”). (F-R characteristic normalization information), and the magnitude of the external force based on the electrical resistance value input from the resistance measurement unit 51 based on the FR characteristic information held in the storage unit 53. And a calculation unit 54 for calculating the height. Information on the magnitude of the external force calculated by the calculation unit 54 is input to the control unit of the touch panel 10 by an output unit (not shown), and display control of the screen of the touch panel 10 is performed.

  Next, a procedure for measuring the FR characteristic of the pressure sensor will be specifically described.

  First, for example, five samples of the pressure-sensitive sensor 120 configured as shown in FIG. 16 are prepared. Although the pressure-sensitive sensor 120 has a configuration in which the planar arrangement of the pressure-sensitive ink members 23a and 23b is different from the pressure-sensitive sensor 20 of the first embodiment described above, the other configurations are the same as those of the pressure-sensitive sensor 20. It has basically the same configuration.

  Specifically, as shown in FIG. 16, in the pressure-sensitive sensor 120, five (a total of ten) sensations are provided at equal intervals on two opposite sides on the long side of the frame-shaped upper electrode 21a. A pressure ink member 23a is disposed. The lower electrode has the same arrangement configuration as that of the upper electrode 21a.

  Five samples of such pressure-sensitive sensor 120 are prepared, and a key-pressing test is performed with a key-pressing tester at the center position P1 on the panel surface, and data on the relationship between the additional external force and the electric resistance value is measured. A stylus is attached to the tip (external force applied portion) of the key test machine, and the additional external force is changed in increments of 50 gf from 0 gf to 400 gf. Measure with The graph of FIG. 17 shows the FR characteristic data of the five pressure sensor 120 samples.

  In the graph of the FR characteristic in each sample of the pressure sensor 120 shown in FIG. 17, the horizontal axis indicates the additional external force F (gf), and the vertical axis indicates the electric resistance value R (Ω). As is clear from the graph shown in FIG. 17, it can be seen that there is a variation in FR characteristics (variation between individuals) between samples.

  Next, data processing is performed to suppress variation in individual FR characteristics in each sample of the pressure-sensitive sensor 120. That is, data processing is performed so that the variation in the FR characteristics among individuals does not stand out in the data.

Specifically, the resistance value R _(Fmax) when the set maximum external force F _max of the pressure sensor 120 is applied (for example, when an external force of 400 gf is added ₎ , the resistance value R _(F0) when no external force is applied, and the set maximum external force. Using an external force F _X less than F _max (for example, an external force in increments of 50 gf from an external force of 50 gf to 350 gf ₎ and the resistance value R _(FX) when applied (that is, using the data shown in the graph of FIG. 17), a number 3 standardizes the FR characteristic. That is, the F-R characteristic standard so that the electrical resistance value R when the additional external force F = F ₀ (zero) is 0 and the electrical resistance value R when the additional external force F = F _max is 1. Data processing for conversion.
(Equation 3)
S _(FX) = {1 / R _(FX) −1 / R _(F0) } / {1 / R _(Fmax) −1 / R _(F0) }

The graph of FIG. 18 shows the _FR characteristics (standardized information of FR characteristics) S _(FX) for each sample standardized by using this equation 3. In the graph of FIG. 18, the abscissa indicates the additional external force (gf), and the ordinate indicates the normalized value (0 to 1).

As shown in FIG. 18, it can be seen that the variation between the five samples is clearly suppressed in the FR characteristic S _(FX) after normalization compared to the FR characteristic before normalization. .

Next, the standardized information S _(FX) of the FR characteristic of each pressure sensor 120 processed in this way is stored in the storage unit 53 of the pressing force detection unit 50.

When an external force is actually applied to the panel surface by the pressure sensor 120, the electrical resistance value of the pressure-sensitive ink member is measured by the resistance measurement unit 51, and the storage unit 53 is calculated by the calculation unit 54. The external force added is calculated from the measured electrical resistance value based on the standardized information S _(FX) of the _FR characteristic stored in FIG.

In this way, data processing for normalizing the FR characteristic by Equation 3 is performed, and the additional external force is calculated from the electric resistance value based on the normalized information S _(FX) of the _FR characteristic. Accordingly, it is possible to suppress variation in FR characteristics among the pressure-sensitive sensors 120. In particular, such data processing for standardization does not correct the relationship between the electrical resistance value and the additional external force, but is a data process that changes the way the data is viewed. Data processing can be performed while maintaining the relationship with the external force. Therefore, variation in the measurement accuracy of the external force between products can be suppressed, and a pressure-sensitive sensor having stable measurement accuracy can be provided.

(Second Embodiment)
In addition, this invention is not limited to the said embodiment, It can implement with another various aspect. For example, a pressure sensor according to a second embodiment of the present invention will be described.

  FIG. 19 is a diagram showing the arrangement of the pressure-sensitive sensor in the touch input device, FIG. 20 is an exploded view of the pressure-sensitive sensor, FIG. 21 is a cross-sectional view taken along the line A3-A3 of FIG. FIG.

  As shown in FIGS. 19 to 21, the pressure sensor 220 includes an upper film 221 and a lower film 222. On the surface of the upper film 221 on the lower film 222 side, the upper electrode 221a is arranged in a frame shape. On the surface of the lower film 222 on the upper film 221 side, the lower electrode 222a is arranged in a frame shape so as to face the upper electrode 221a.

  A frame-shaped upper pressure-sensitive ink member 223a is disposed on the upper film 221 so as to cover the upper electrode 221a. Similarly, in the case of the lower film 222, a frame-shaped lower pressure-sensitive ink member 223b is disposed on the lower film 222 so as to cover the lower electrode 222a and to face the upper pressure-sensitive ink member 223a.

  That is, the pressure-sensitive sensor 220 according to the second embodiment of the present invention includes an upper electrode 221a formed on the upper film 221 and a lower electrode 222a formed on the lower film 222 so as to face the upper electrode 221a. And an upper pressure-sensitive ink member 223a that covers the upper electrode 221a, and a lower pressure-sensitive ink member 223b that covers the lower electrode 222a so as to face the upper pressure-sensitive ink member 223a.

  An adhesive member 230 is disposed in a region where the upper film 221 and the lower film 222 are opposed to each other and at the peripheral edge portions of the pressure-sensitive ink members 223a and 223b. The adhesive member 230 may be, for example, an elastic adhesive agent or double-sided adhesive material, or various elastic members such as rubber, tension coil springs, leaf springs, etc. that are set to exert a tensile force. It may be. When the adhesive member 230 having elasticity is used as described above, the thickness of the adhesive member 230 in a free state is thinner than the total thickness of the pair of electrodes 221a and 222a and the pressure-sensitive ink members 223a and 223b. It is preferable that it is comprised so that it may become. If comprised in this way, the force which is going to hold | maintain original thickness will act on the arrange | positioned adhesive member 230, and this force acts in the direction which makes the upper film 221 and the lower film 222 adjoin each other. Thus, by reducing the distance between the upper film 221 and the lower film 222 and reducing the thickness of the pressure-sensitive ink member 23 in the non-pressurized state, an initial load is applied to the pressure-sensitive ink members 223a and 223b as a result. Can be granted. As a result, the initial unstable detection value is automatically eliminated, and the detection accuracy of the pressing force can be improved even when the pressure sensor detects the pressing force with a light load.

  Instead of using an elastic member as the adhesive member 230, an inelastic member may be used. In such a case, the adhesive member 230 is, for example, an inelastic spacer that is thinner than the total thickness of the pair of electrodes 221a and 222a and the pressure-sensitive ink members 223a and 223b. When the deformation of the upper film 221 or the lower film 222 is allowed, the pressure-sensitive ink members 223a and 223b to which the initial load is applied are further compressed through the upper film 221 or the lower film 222 to detect the pressing force. Can do.

  As shown in FIG. 22, the pressure sensor 220 according to the second embodiment of the present invention may further include bumps 224 a on the outer surface of the lower film 222. By arranging the bumps 224a in this way, when an external load is applied to the pressure sensor 220, the bumps 224a support the lower pressure-sensitive ink member 223b from below, and concentrate the load to lower pressure-sensitive ink. It can be transmitted to the member 223b. Furthermore, the bump 224a is preferably disposed on the back side (directly below) where the pressure-sensitive ink members 223a and 223b are disposed. With this configuration, as shown in FIG. 23, the upper pressure-sensitive ink member 223a and the lower pressure-sensitive ink member 223b can be reliably pressed against each other, and the pressure measurement accuracy of the pressure-sensitive sensor 220 can be improved. Can do.

(Third embodiment)
Next, a pressure sensor according to a third embodiment of the present invention will be described. 24 is a layout diagram of the pressure-sensitive sensor in the touch input device, FIG. 25 is an exploded view of the pressure-sensitive sensor, and FIG. 26 is a sectional view taken along line A4-A4 in FIG.

  Since the basic configuration of the pressure-sensitive sensor 320 according to the third embodiment is the same as that of the pressure-sensitive sensor 220 according to the second embodiment, the bump formation position which is a characteristic part in the third embodiment is described. Only described below.

  As shown in FIGS. 24 to 26, in the pressure-sensitive sensor 320, a bump 324a is disposed between the lower film 322 and the lower electrode 322b. The bump 324a is formed so that its installation area is equal to or less than the installation area of the electrode 322a.

  A pressure-sensitive ink member 323 and a bump 324a are disposed in a region where the upper film 321 and the lower film 322 are opposed to each other. Therefore, when manufacturing the pressure-sensitive sensor 320, the bump 324a, the lower electrode 322a, and the lower pressure-sensitive ink member 323b are sequentially arranged on the lower film 322 by using, for example, a printing process. That is, since the substrate portion on one side of the pressure sensor 320 is formed in a series of steps, the positional displacement of each layer of the bump 324a, the lower electrode 322a, and the lower pressure-sensitive ink member 323b on the lower film 322 hardly occurs. In addition, it is not necessary to separately form bumps on the outer surface of the film of the pressure sensor 320, and the manufacturing process is simplified. Therefore, the productivity of the pressure sensor 320 provided with the bump 324a can be improved.

  Further, with this configuration, when an external load is applied to the pressure sensor 323, the bump 324a supports the lower pressure-sensitive ink member 323b from below and concentrates the load to lower the pressure-sensitive ink member. 323b (see FIG. 27). As a result, the upper pressure-sensitive ink member 323a and the lower pressure-sensitive ink member 323b are reliably pressed against each other, and the pressure measurement accuracy of the pressure-sensitive sensor 320 can be improved. Further, since the bumps 324a are not exposed on the outer surface of the lower film 322, the bumps 324a are not peeled off from the pressure detection unit 320 by rubbing against an external member.

  In the third embodiment, the upper film 321 and the lower film 322 have the same thickness, but the upper film 321 and the lower film 322 may have different thicknesses. In the modification shown in FIG. 28, the thickness of the lower film 322 is set to be thinner than the thickness of the upper film 321. By doing so, the lower film 322 having a smaller thickness is more easily deformed than the upper film 321, and the pressure sensor 320A in which the bump 324a disposed between the upper film 321 and the lower film 322 protrudes in a convex shape in the lower part. Is easily formed. When the shape of the pressure sensor 320A on the lower film 322 side is convex, the contact area between the pressure sensor 320 and the upper frame portion 2b as an external member is reduced, and the load from the upper frame portion 2b is reduced by the pressure sensor. The concentrated ink is transmitted to the pressure-sensitive ink member 323b of 320A. As a result, the measurement accuracy of the pressing force of the pressure sensor 320A can be improved.

  In the third embodiment, the example in which the bump 324a is disposed only between the lower film 322 and the lower pressure-sensitive ink member 323b has been described. However, instead of such a case, the bump 324a is connected to the upper film 21. You may arrange | position between the upper pressure sensitive ink members 23a. Further, as in the pressure-sensitive sensor 320B according to the modification shown in FIG. 29, the bump 324a is provided between the upper film 321 and the upper pressure-sensitive ink member 323a and between the lower film 322 and the lower pressure-sensitive ink member 323b. May be arranged. When the bumps 324a are arranged both above and below the pressure-sensitive ink member 323, the pressure-sensitive ink members 323a and 323b are more reliably pressed by the upper and lower bumps 324a. Therefore, the measurement accuracy of the pressure-sensitive ink members 323a and 323b is improved as compared with the case where the bump 324a is disposed only above or below the pressure-sensitive ink members 323a and 323b.

  In the third embodiment, the example in which the pressure-sensitive ink members 323a and 323b are also arranged in the frame shape with respect to the electrodes 321a and 322a arranged in the frame shape has been described, but instead of such a case. Alternatively, the pressure-sensitive ink members 323a and 323b may be interspersed with the electrodes 321a and 322a arranged in a frame shape.

  In the third embodiment, the adhesive member 330 is disposed between the upper film 321 and the lower film 322 to apply the initial load to the pressure-sensitive ink members 323a and 323b. However, only in such a case. It is not limited. For example, like the pressure-sensitive sensor 320C according to the modification shown in FIG. 30, the upper film 321 and the lower film 322 are fused so that the pair of electrodes 321a and 322a and the pressure-sensitive ink members 323a and 323b are in contact with each other. The initial load may be applied to the pressure-sensitive ink members 323a and 323b.

(Fourth embodiment)
In the first to third embodiments, specific configurations and methods for suppressing variations in FR characteristics among individual pressure sensors based on standardized information of FR characteristics in the pressure sensor will be described. However, such a concept of the present invention can be applied to sensors other than the pressure-sensitive sensor. That is, the concept of the present invention can be applied to a sensor having a sensor member whose electrical characteristics change when receiving an external input. Such external inputs include, for example, light, sound, heat, etc. in addition to external force, and electrical characteristics include, for example, voltage (partial voltage), current, capacitance, etc., in addition to resistance. There is. The concept of the case of applying the concept of the present invention to a sensor that detects an external input will be described below.

  First, FIG. 31 is a block diagram showing a main configuration of a sensor 420 as an example of the sensor according to the fourth embodiment. As shown in FIG. 31, the sensor 420 receives an external input such as light, sound, heat, etc., for example, a sensor member 423 whose electrical characteristics such as voltage, current, capacitance, etc. change, and a sensor member And an external input detection unit 450 that detects an external input input (added) to 423. The external input detection unit 450 is input to the sensor 420 based on the electrical property measurement unit 451 that measures the electrical property value of the sensor member 423 and the electrical property value measured by the electrical property measurement unit 451. External input calculating means 452 for calculating the size of the external input. The electrical characteristic measuring unit 451 and the external input calculating unit 452 are configured as an electric circuit.

  The external input calculating unit 452 has information of “external input-electric characteristic (hereinafter referred to as“ Y-C characteristic ”)” indicating the relationship between the external input input to the sensor member 423 and the electric characteristic value (hereinafter referred to as “YC characteristic”). YC characteristic normalization information), and based on the YC characteristic information held in the storage part 453, based on the electric characteristic value input from the electric characteristic measuring means 451 And an arithmetic unit 454 for calculating the size of the external input.

  Next, a procedure for measuring the YC characteristic of the sensor 420 will be described.

  First, a plurality of samples (products) of the sensor 420 having such a configuration, for example, three (samples 420a, 420b, 420c) are prepared, and an external input is added to each sensor 420 to be added. Data on the relationship between the external input and the electrical characteristic value is acquired. For example, as an external input, an external input in a range from 0 to a set maximum value is added to the sensor 420, and the electrical characteristic value of the sensor member 523 when each external input is added is an electrical characteristic measuring unit. Measure at 451. Data of YC characteristics in the samples of the three sensors 420a to 420c are shown in the graph of FIG.

  In the graph of the Y-C characteristics in the samples of the respective sensors 420a to 420c shown in FIG. 32, the horizontal input indicates the external input Y, and the vertical axis indicates the electrical characteristic value C. As is clear from the graph shown in FIG. 32, it can be seen that there is a variation in Y-C characteristics between the samples. This variation is a variation between individual products of the sensors 420a to 420c.

  Next, data processing is performed to suppress variation in individual YC characteristics among the samples of the sensors 420a to 420c.

Specifically, the electrical characteristic value C _(Ymax) when the external input setting maximum value Y _max of the sensor 420 is added, the electrical characteristic value C _(Y0) when no external input is added, and the external input setting. Using the electrical characteristic value C _(YX) when the external input Y _X less than the maximum value Y _max is added (that is, using the data shown in the graph of FIG. 32), the Y-C characteristic is calculated based on Equation 4. Standardize. That is, the electrical characteristic value C when the added external input Y = Y ₀ (zero) is expressed as 0, and the electrical characteristic value T when the added external input Y = Y _max is expressed as 1. As described above, data processing for standardization of Y-C characteristics is performed.
(Equation 4)
S _(YX) = {1 / C _(YX) −1 / C _(Y0) } / {1 / C _(Ymax) −1 / C _(Y0) }

A graph of FIG. 33 shows _YC characteristics (standardized information of _YC characteristics) S _(YX) for each sample standardized using Equation 4. In the graph of FIG. 33, the horizontal input indicates the external input Y, and the vertical axis indicates the normalized value S (the normalized value of the electrical characteristic value C).

As shown in FIG. 33, the variation among the three samples 420a to 420c can be suppressed in the YC characteristic S _(YX) after normalization compared to the YC characteristic before normalization.

Next, the standardized information S _(YX) of the YC characteristics of the individual sensors 420 a to 420 c processed in this way is stored in the storage unit 453 of the external input detection unit 450.

In the sensor 420, when an external input is actually added, the electrical characteristic value of the sensor member 423 is measured by the electrical characteristic measuring unit 451 and stored in the storage unit 453 by the calculation unit 454. Based on the normalized information S _(YX) of the Y-C characteristic, an external input added from the measured electrical characteristic value is calculated.

In this way, the data processing for normalizing the YC characteristic is performed using Equation 4, and the external input added from the electrical characteristic value based on the standardized information S _(YX) of the _YC characteristic. Is calculated, it is possible to suppress variations in Y-C characteristics among the sensors 420a to 420c. In particular, such data processing for standardization does not correct the relationship between the electrical characteristic value and the added external input, but is data processing that changes the appearance of the data. Data processing can be performed while maintaining the relationship between the target characteristic value and the added external input. Therefore, variations in the measurement accuracy of external input between products can be suppressed, and a sensor having stable measurement accuracy can be provided.

  Therefore, the idea of the present invention that suppresses the variation in the YC characteristics among the individual sensors based on the standardized information of the YC characteristics in such a sensor is that the electrical characteristics are obtained by receiving an external input. The present invention can be applied to a sensor having a sensor member that changes.

  Several examples of sensors to which the concept of the present invention can be applied will be described. For example, the present invention can be applied to a pressure sensor that uses a voltage generated by applying pressure to a piezoelectric element, with a sensor member as a piezoelectric element, an external input as pressure, and a change in electrical characteristics as a voltage change. it can. In addition, if the sensor member is an electrostatic sensor (capacitor), the external input is in contact with the finger, and the change in electrical characteristics is a change in capacitance value, the capacitance value changes when the finger touches the electrostatic sensor (closes the finger). The present invention can be applied to a contact sensor that utilizes the fact that the angle changes. In addition, the present invention is applied to an optical sensor that utilizes a change in resistance value by irradiating light to a light receiving element, with a sensor member as a light receiving element, external input as light irradiation, and a change in electrical characteristics as resistance change. can do. In addition, the present invention can be applied to a temperature sensor that utilizes the change in resistance value when the temperature of the thermistor changes, with the sensor member as the thermistor, the external input as the temperature, and the change in electrical characteristics as the resistance change.

  It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the effects possessed by them can be produced.

  The pressure-sensitive sensor according to the present invention can suppress a decrease in the visibility of the display unit of the display device even when mounted on an electronic device having a touch panel, and can improve pressure measurement accuracy. The present invention is useful for electronic devices including portable electronic devices such as mobile phones and game machines. Further, the sensor according to the present invention is useful in various industries in which such a sensor is used because it can reduce variations in measurement accuracy among individuals in a sensor that measures external inputs such as light, sound, and heat. .

DESCRIPTION OF SYMBOLS 1 Cellular phone 2 Housing | casing 2A Display window 3 Display apparatus 3A Display part 4 Touch input device 4A Transparent window part 4B Decorating area 5 Input key 10 Touch panel 11 Transparent support substrate 12 Decorating film 13 X-axis detection transparent film 13a Upper transparent Electrode 13b Route circuit 14 Transparent adhesive layer 15 Y-axis detection transparent film 15a Lower transparent electrode 15b Route circuit 16 Transparent adhesive layer 17 Shield transparent film 17a Shield transparent electrode 17b Route circuit 18 Transparent adhesive layer 19 Hard coat film 20 Pressure sensitive Sensor 21 Upper film 21a Upper electrode 22 Lower film 22a, 22b Lower electrode 23a, 23b Pressure sensitive ink member 24 Gap holding member 50 Pressing force detection part 51 Resistance measurement part 52 External force calculation means 53 Storage part 54 Calculation part

Claims (9)

First and second substrates disposed opposite each other;
A pair of electrodes disposed between the first and second substrates;
A conductive pressure-sensitive ink member that is disposed between a pair of electrodes and receives an external force applied in the thickness direction of the first substrate to change its electrical resistance;
A resistance measuring unit that is connected to the pair of electrodes and receives an external force in the thickness direction of the first substrate and measures an electrical resistance value of the pressure-sensitive ink member in contact with the pair of electrodes;
Measured by the resistance measuring means, and the resistance value of the set maximum force _{F max} upon application of the pressure sensitive ink members _{R (Fmax),} and the resistance value at no external force applying _{R (F0),} an external force less than the set maximum force _{F max} F by using the _X additional resistance at R _(FX), the external force is normalized based on the number 1 - holding the resistance characteristic normalization information S _(FX), an external force - normalized information resistance characteristic S _{( FX)} based on _FX) , and an external force calculation means for calculating an external force added from the resistance value measured by the resistance measurement means.
(Equation 1)
S _(FX) = {1 / R _(FX) −1 / R _(F0) } / {1 / R _(Fmax) −1 / R _(F0) } The pair of electrodes are arranged on one of the opposing surfaces of the first and second substrates or arranged separately on both, and arranged in a frame shape along the edge of the first or second substrate,
A gap holding member disposed between the first and second substrates so as to bond the first substrate and the second substrate, and holding a gap between at least one of the pair of electrodes and the pressure-sensitive ink member. Further comprising
The pressure-sensitive ink member exists along the edge of the first or second substrate, and an external force is applied in the thickness direction of the first substrate, thereby reducing the distance between the first and second substrates. The pressure-sensitive sensor according to claim 1, wherein the pressure-sensitive sensor is brought into contact with a pair of electrodes to conduct the two. The pair of electrodes are disposed opposite to the first and second substrates,
The pressure-sensitive ink member is disposed between the pair of electrodes in a state of covering at least one of the pair of electrodes,
An adhesive member is provided between the first and second substrates so as to bond the first substrate and the second substrate, and brings the pressure-sensitive ink member into contact with at least one of the pair of electrodes. The pressure-sensitive sensor according to claim 1.   The pressure-sensitive sensor according to claim 3, wherein the adhesive member applies an initial load to the pressure-sensitive ink member by attracting the first substrate and the second substrate.   4. The bump according to claim 1, wherein a bump that concentrates and transmits a load to the pressure-sensitive ink member is provided on at least one of the outer surface of the first substrate and the outer surface of the second substrate. The pressure-sensitive sensor described.   A bump is disposed between at least one of the first substrate and the pressure-sensitive ink member and between the second substrate and the pressure-sensitive ink member, and transmits the load while concentrating the load on the pressure-sensitive ink member. The pressure-sensitive sensor according to any one of claims 1 and 3 to 5.   The pressure-sensitive sensor according to claim 6, wherein the thickness of the first substrate and the thickness of the second substrate are different.   The pressure-sensitive sensor according to claim 6 or 7, wherein the bumps are disposed between the first substrate and the pressure-sensitive ink member and between the second substrate and the pressure-sensitive ink member. A sensor member that changes its electrical characteristics in response to an external input;
An electrical property measuring means having an electrical circuit for measuring electrical property values of the sensor member;
The electric characteristic value C _(Ymax) when the sensor member external input set maximum value Y _{max is} added and the electric characteristic value C _(Y0) when no external input is added, measured by the electric characteristic measuring means , by using the electric resistance value C _(YX) during the addition of the external input Y _X set smaller than the maximum value Y _max of the external input, normalized external input based on the number 2 - normalized electrical characterization information S _(YX) is held, and the external input added to the sensor member is calculated from the electric characteristic value measured by the electric characteristic measuring means based on the external input-electrical characteristic standardization information S _(YX). And an external input calculating means.
(Equation 2)
S _(YX) = {1 / C _(YX) −1 / C _(Y0) } / {1 / C _(Ymax) −1 / C _(Y0) }

Images