JP6422769B2 - Capacitance detection device and portable information terminal - Google Patents

Description

  The present invention relates to a capacitance detection device and a portable information terminal that detect capacitance.

  A touch panel that detects the contact of a finger or the like is used on the side of the casing of the mobile phone terminal. As a method for detecting the contact of a finger or the like, a capacitance detection method for detecting a contact by detecting a change in capacitance is widely used. Patent Document 1 discloses a capacitance detection device including two sensor electrodes and a detection integrated circuit for detecting a change in capacitance between the sensor electrodes.

  FIG. 8 is a diagram illustrating a configuration of a conventional capacitance detection device. The capacitance detection device 100 includes a sensor electrode unit 101, a wiring 102, a detection circuit 103, and an electrostatic breakdown prevention circuit 104. The detection circuit 103 is connected to the sensor electrode unit 101 by a wiring 102. In FIG. 8, only one sensor electrode unit 101 is illustrated, but a plurality of sensor electrodes are actually connected to the detection circuit 103.

  The sensor electrode unit 101 forms a capacitance with the ground electrode having a predetermined potential. Then, when a user's finger or the like approaches (including the case where the user's finger is in contact and the case where the user's finger is separated at a short distance. The same applies hereinafter), a capacitance is formed between the user's finger and the like. The sensor electrode unit 101 is grounded to the ground electrode through the user's finger, and the capacitance formed between the finger varies depending on the distance from the finger. The detection circuit 103 detects the position where the finger is close to the surface on which the sensor electrode unit 101 is arranged, based on the capacitance formed between the sensor electrode unit 101 and the finger, and outputs the detected signal to the outside.

  In general, an electrostatic breakdown preventing circuit 104 is provided in the path between the sensor electrode unit 101 and the detection circuit 103 to prevent the subsequent detection circuit 103 from electrostatic breakdown. The electrostatic breakdown preventing circuit 104 includes a coil, a capacitor, and / or a diode.

JP 2007-324088 (released December 13, 2007)

  When the capacitance detection device 100 is arranged in a limited space such as a mobile phone terminal, the capacitance detection device 100 is arranged at a location close to the cellular antenna 110 or the like. Thus, when the distance between the antenna 110 and the sensor electrode unit 101 is short, the signal Q mixed with the high-frequency transmission wave P from the antenna 110 into the sensor electrode unit 101 is a circuit component of the electrostatic breakdown prevention circuit 104 ( Resonance is generated by a coil, a capacitor, and / or a diode, and the harmonic R is generated. Since the harmonic wave R may exceed the standard value of the standard to which the unnecessary radiation should comply, it is a target to be suppressed. In addition, due to the influence of unnecessary radiation, the detection circuit 103 may not be able to accurately detect a change in the capacitance formed between the sensor electrode unit 101 and the finger. As described above, the harmonic wave R generated in the capacitance detection device 100 when the transmission wave P from the antenna 110 is mixed into the sensor electrode unit 101 prevents accurate position detection.

  The object of the present invention has been made in view of the above-mentioned conventional problems, and the object is to prevent malfunction when detecting capacitance.

  In order to solve the above-described problem, a capacitance detection device according to an aspect of the present invention detects a capacitance and a capacitance forming unit that forms a capacitance between adjacent objects. A detection circuit that outputs a detection signal indicating that the detection signal has been received, and a resonance of the harmonic signal superimposed on the detection signal when the harmonic signal is input to the capacitance formation unit; And a resonating part arranged in contact with.

  In order to solve the above-described problem, a capacitance detection device according to an aspect of the present invention detects a capacitance and a capacitance forming unit that forms a capacitance between adjacent objects. A detection circuit that outputs a detection signal indicating that the capacitance is formed, and a ground electrode portion that is spaced apart from the capacitance forming portion and surrounds the periphery of the capacitance forming portion.

  According to one embodiment of the present invention, it is possible to prevent malfunction when detecting capacitance.

FIG. 3 is a plan view illustrating a configuration of a sensor electrode unit of the capacitance detection device according to the first embodiment. 1 is a diagram illustrating a schematic configuration of a capacitance detection device according to a first embodiment. 3 is a diagram illustrating a configuration of a detection circuit of the capacitance detection device according to the first embodiment. FIG. It is a figure showing the relationship between the frequency of a signal, and SWR. 1 is a perspective view of a mobile phone terminal in which a capacitance detection device according to Embodiment 1 is used. It is a figure showing schematic structure of the electrostatic capacitance detection apparatus which concerns on Embodiment 2. FIG. 6 is a plan view illustrating a configuration of a sensor electrode unit of a capacitance detection device according to a second embodiment. FIG. It is a figure showing the structure of the conventional electrostatic capacitance detection apparatus.

Embodiment 1
(Schematic configuration of the capacitance detection device 1)
FIG. 2 is a diagram illustrating a schematic configuration of the capacitance detection device 1. As shown in FIG. 2, the capacitance detection device 1 includes a plurality of sensor electrode units 10, a detection circuit 20, one or a plurality of coils 2, and one or a plurality of diode groups 3 that are electrostatic countermeasure components. ing. The capacitance detection device 1 is a device for detecting the proximity of an object close to the surface on which the sensor electrode unit 10 is disposed to the surface and outputting the detected result to the outside as a detection signal. . For example, the capacitance detection device 1 is a contact detection device or the like disposed on the side surface of the housing. The target that the capacitance detection device 1 detects proximity is, for example, a human body such as a user's finger.

  The sensor electrode unit 10 is disposed on a surface for the user to hold the casing or to touch or approach a finger or the like. The sensor electrode unit 10 is connected to the detection circuit 20 by a wiring 25. The sensor electrode unit 10 forms a capacitance between the sensor electrode unit 10 and an adjacent object, and also removes unnecessary radiation generated by inputting a high-frequency signal from the outside to the sensor electrode unit 10 by resonance. The capacitance formed between the sensor electrode unit 10 and the target object varies depending on the distance from the adjacent target object. A specific configuration of the sensor electrode unit 10 will be described later.

  Note that the “proximity” means that the object and the surface on which the sensor electrode unit 10 is disposed are in contact with each other, and the object and the surface on which the sensor electrode unit 10 is disposed are separated from each other. In addition, it includes a state where the distance between the object and the surface on which the sensor electrode unit 10 is disposed is close to the extent that capacitance can be formed between the two. The same applies to the following description.

  The detection circuit 20 detects the proximity of the object in the plane where the sensor electrode unit 10 is arranged, from the capacitance formed between the sensor electrode unit 10 and the adjacent object, and the proximity of the object A detection signal indicating that has been detected is generated, and the detection signal is output to the outside.

  The coil 2 is a circuit unit for adjusting the capacitance for adjusting the capacitance formed between the sensor electrode unit 10 and an adjacent object. The coil 2 is disposed on the wiring 25 in the path between the sensor electrode unit 10 and the detection circuit 20. As an example, in FIG. 2, two coils 2 connected in series are arranged on a wiring 25 between the sensor electrode unit 10 and the detection circuit 20. Note that the number of the coils 2 is not limited to two and is arbitrary.

  The diode group 3 is a circuit unit for countermeasures against static electricity for preventing the detection circuit 20 from malfunctioning or being destroyed by static electricity input from the sensor electrode unit 10. As an example, the diode group 3 includes a diode 3a and a diode 3b. The cathode of the diode 3a is connected to the anode of the diode 3b and grounded. The anode of the diode 3 a is connected to the cathode of the diode 3 b and to the wiring 25 that connects the coil 2 and the detection circuit 20. The diode group 3 only needs to be disposed in a path connecting the sensor electrode unit 10 and the detection circuit 20. Further, the number of diodes constituting the diode group 3 is not limited to four and is arbitrary.

(Configuration of the detection circuit 20)
FIG. 3 is a diagram illustrating the configuration of the detection circuit 20. The configuration of the detection circuit 20 illustrated in FIG. 3 is an example. Even if the configuration of the detection circuit 20 is other than the configuration shown in FIG. 3, the capacitance formed between the sensor electrode unit 10 and the human body in contact with or close to the sensor electrode 10 is detected, and the detected signal is externally detected. Any configuration can be used as long as the output can be output.

  The detection circuit 20 includes a substrate 21, a detection integrated circuit 22 disposed on the substrate 21, a shield layer 24, and a wiring 25. The detection integrated circuit 22 includes an oscillator 26 as a high-frequency signal source, a resistor 27, a selector 29, the same number of electrode pads 30 as the sensor electrode unit 10, amplifiers 31 and 35, electrode pads 36, and a signal processing circuit. 32. Underneath the wirings 25, 28 and the electrode pads 30, shield layers 24, 33 and 34 made of a conductor are arranged via insulating layers (not shown).

  The resistor 27 has one end connected to the oscillator 26 and the other end connected to the wiring 28. The other end of the wiring 28 opposite to the one connected to the resistor 27 forms an independent wiring portion 28 a branched in the selector 29 in the same number as the electrode pad 30. Each wiring portion 28 a is connected to the electrode pad 30. Each electrode pad 30 is individually connected to the input terminal of the amplifier 31 via the selector 29, and the output terminal of the amplifier 31 is connected to the signal processing circuit 32. The output terminal of the amplifier 31 is connected to the input terminal of the amplifier 35, and the output terminal of the amplifier 35 is connected to the shield layer 24 and all the shield layers 34 via the electrode pads 36.

  The high frequency signal generated by the oscillator 26 is supplied to the sensor electrode unit 10 via the electrode pad 30 and the wiring 25 selected by the selector 29. The high frequency signal from the oscillator 26 attenuated according to the capacitance formed between each sensor electrode unit 10 and the object is output to the amplifier 31 as the detection signal a. Then, the detection signal a amplified by the amplifier 31 is converted into a signal having an output level corresponding to the capacitance by, for example, rectification in the signal processing circuit 32 and each sensor. The capacitance formed by the electrode unit 10 is detected, and the signal is output to the outside. The detection signal a amplified by the amplifier 31 is supplied to the shield layers 24, 33, and 34 as the shield signal b having the same phase and the same amplitude as the detection signal a through the amplifier 35 and the electrode pad 36. Thereby, the parasitic capacitance of the wirings 25 and 28 and the electrode pad 30 is reduced.

(Configuration of sensor electrode)
FIG. 1 is a plan view illustrating a configuration of a sensor electrode unit 10 of the capacitance detection device 1 according to the first embodiment. The sensor electrode unit 10 includes a capacitance forming unit 11 and a resonance unit 13 that resonates with a signal having a specific frequency.

  The capacitance forming unit 11 forms a capacitance between the sensor electrode unit 10 and an object such as a finger close to the sensor electrode unit 10. For example, the capacitance forming unit 11 is made of a copper film or the like. In the present embodiment, the capacitance forming unit 11 has a rectangular shape, and has a configuration in which a wiring 25 connected to the detection circuit 20 is connected to one of the short sides. In addition, the shape of the capacitance forming portion 11 can take various other shapes. For example, the shape of the capacitance forming unit 11 may be a triangle, a square, a polygon other than a quadrangle, or a circle. The resonating unit 13 resonates with respect to a predetermined predetermined harmonic frequency.

  The resonance unit 13 includes a resonator such as an interdigital transducer (IDT). The resonance unit 13 is in contact with the capacitance forming unit 11. Thereby, the signal used as the unnecessary radiation input into the electrostatic capacitance formation part 11 can be reduced.

  The resonating unit 13 resonates with the harmonic frequency superimposed on the detection signal when a high frequency signal is input to the capacitance forming unit 11 from the outside. The high-frequency signal input from the outside to the capacitance forming unit 11 is, for example, a transmission signal from a cellular antenna or the like disposed near the capacitance detection device 1. When the capacitance forming unit 11 and the antenna are arranged in a narrow housing such as a mobile phone terminal, the distance between the capacitance detection device 1 and the antenna is short, and the antenna transmits a transmission signal to the outside. A high-frequency signal may be input to the capacitance forming unit 11.

  The resonance unit 13 resonates with the frequency of the harmonics superimposed on the detection signal due to the high frequency signal input to the capacitance forming unit 11, so that the detection signal is caused by the high frequency signal which is unnecessary radiation. Superposed harmonics can be reduced. For this reason, it is possible to prevent the detection circuit 20 from malfunctioning when detecting the capacitance due to the input of the high-frequency signal to the capacitance forming unit 11. As a result, it is possible to obtain the capacitance detection device 1 that is unlikely to malfunction when detecting the capacitance.

  The resonance unit 13 has one end connected to the capacitance forming unit 11 and the other end extending in a direction away from the capacitance forming unit 11, and a plurality of branch units 13b intersecting and contacting the trunk 13a. have. Thus, the resonance part 13 can be comprised. By adjusting the thickness and length of the trunk portion 13a and the branch portion 13b, the interval between the branch portions 13b, and the like, the resonance is caused by the frequency at which the resonance portion 13 resonates, that is, the desired harmonic frequency to be removed from the detection signal. It adjusts so that the part 13 may resonate. Thereby, it is possible to obtain the capacitance detection device 1 that prevents the generation of specific harmonics and does not affect the detection sensitivity of the capacitance.

  As shown in FIG. 2, the coil 2 and the diode group 3 are arranged on the wiring 25 that connects the capacitance forming unit 11 and the detection circuit 20. For example, when the capacitance forming unit 11 and the antenna are arranged in a narrow housing such as a mobile phone terminal, the distance between the capacitance detection device 1 and the antenna is short, and the transmission signal is transmitted to the outside by the antenna. In some cases, a high-frequency signal is input to the capacitance forming unit 11.

  When a high-frequency signal from this antenna is input to the capacitance forming unit 11, the input high-frequency signal is likely to resonate particularly by the coil 2 or the diode group 3, and the signal level of harmonics that are unnecessary radiation increases. . However, since the capacitance detection device 1 according to the present embodiment includes the resonance unit 13, the resonance unit 13 can remove harmonics that resonate with the coil 2 or the diode group 3 and have an increased signal level as unnecessary radiation. it can. In this way, even if a high frequency signal resonates in a circuit subsequent to the capacitance forming unit 11 and unnecessary harmonics are generated, the resonance unit 13 can prevent re-radiation.

  The resonating unit 13 may be patterned with the same material as the capacitance forming unit 11, or may be formed with a material different from that of the capacitance forming unit 11. The resonance unit 13 is shaped so that the maximum point of impedance matches the desired harmonic frequency.

  FIG. 4 is a diagram illustrating the relationship between the frequency of a signal and SWR (Standing wave ratio). In the present embodiment, VSWR (Voltage standing wave ratio) is represented as SWR.

  As shown in FIG. 4, the resonance unit 13 is shaped so that the standing wave ratio (SWR) decreases in a frequency band F including a desired harmonic frequency. Thereby, since the resonance part 13 resonates in the frequency band F, the harmonics can be removed from the detection signal indicating that the detection circuit 20 has detected the capacitance.

In particular, the resonance unit 13 has a shape frequency SWR becomes minimized by the frequency of the harmonics detection signal indicating that the detection circuit 20 detects the electrostatic capacity is the resonant frequency f _0. Thereby, since the resonance part 13 resonates most strongly at the frequency of the harmonic, the harmonic can be more reliably removed from the detection signal.

Adjustment of the resonance frequency f ₀ of the resonance unit 13, the width and length of the stem 13a, can be carried out by adjusting the interval and the branch portions 13b each length between the adjacent branches 13b. The harmonics desired to be removed by the resonating unit 13 vary depending on the circuit configuration of the detection circuit 20, the number and arrangement positions of the coils 2 and the diode groups 3, and the like. Therefore, in determining the shape (that is, impedance) of the resonance unit 13, first, the circuit configuration (the detection circuit 20, the coil 2, and the diode group 3) subsequent to the sensor electrode unit 10 is determined and patterned. From this, the shape (that is, impedance) of the resonating unit 13 is determined. Thereby, a desired harmonic can be reliably removed from the detection signal by the resonance unit 13. The desired harmonics that are preferably removed from the detection signal can be determined, for example, by actually measuring unwanted radiation and adjusting the frequency to be taken into account.

(Personal digital assistant)
FIG. 5 is a diagram showing the appearance of a mobile phone terminal (portable information terminal) 50 in which the capacitance detection device 1 is arranged. The mobile phone terminal 50 includes a touch panel 51 and a housing 52. Further, the mobile phone terminal 50 includes a side surface touch sensor 53 on each side surface. In addition, the mobile phone terminal 50 includes a capacitance detection device 1 and an antenna for transmitting and receiving high-frequency signals for communication such as calls, mails, and the like in a housing 52 that is a limited space. The side touch sensor 53 functions as a device that detects the proximity of an object by providing the sensor electrode unit 10 on each side of the mobile phone terminal 50. Since the capacitance detection device 1 included in the mobile phone terminal 50 includes the resonance unit 13, a high-frequency signal output from an antenna disposed near the capacitance formation unit 11 is input to the capacitance formation unit 11. However, harmonics superimposed on the detection signal due to the high-frequency signal, which is unnecessary radiation, can be reduced. For this reason, it is possible to prevent the side surface touch sensor 53 from malfunctioning when detecting the proximity of the object. As a result, it is possible to obtain the mobile phone terminal 50 in which the side touch sensor 53 is unlikely to malfunction. In addition, the apparatus which provides the electrostatic capacitance detection apparatus 1 is not limited to the mobile phone terminal 50, In addition, what is necessary is just an electronic apparatus by which the components which transmit a high frequency signal are distribute | arranged near the sensor electrode part 10. FIG. In the present embodiment, the example in which the capacitance detection device 1 is used for the side surface touch sensor 53 has been described.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. 4, FIG. 6, and FIG. For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 6 is a diagram illustrating a schematic configuration of a capacitance detection device 1A according to the second embodiment. The capacitance detection device 1A is different from the capacitance detection device 1 (see FIG. 1) in that a sensor electrode unit 40 is provided instead of the sensor electrode unit 10. The other configuration of the capacitance detection device 1A is the same as that of the capacitance detection device 1.

  FIG. 7 is a plan view illustrating the configuration of the sensor electrode unit 40 of the capacitance detection device 1A according to the second embodiment. As shown in FIG. 7, the sensor electrode part 40 includes a capacitance forming part 41 and a ground electrode part 42. The capacitance forming unit 41 is the same as the capacitance forming unit 11. The ground electrode portion 42 is separated from the capacitance forming portion 41 and surrounds the periphery of the capacitance forming portion 41. Specifically, the ground electrode portion 42 includes an extending portion 42 a that faces one long side of the capacitance forming portion 41, an extending portion 42 c that faces the other long side of the capacitance forming portion 41, and a static electrode. The capacitance forming portion 41 includes an extending portion 42 b facing the other short side opposite to the one short side connected to the wiring 25. The ground electrode portion 42 surrounds three sides other than one short side connected to the wiring 25 in the capacitance forming portion 41 by the extending portions 42a, 42b, and 42c. Thereby, the ground electrode part 42 functions as a ground for a high-frequency signal input from the outside such as an antenna. Further, the ground electrode portion 42 functions so as to appear open (insulated) with respect to a direct current (DC) voltage.

  Thereby, the ground electrode part 42 can suppress that a high frequency signal is input to the capacitance forming part 41 from the outside such as an antenna. Thereby, the harmonics superimposed on the detection signal due to the high-frequency signal, which is unnecessary radiation, can be reduced.

  For this reason, it is possible to prevent the detection circuit 20 from malfunctioning when detecting the capacitance due to the input of the high-frequency signal to the capacitance forming unit 41. As a result, it is possible to obtain a capacitance detection device 1A that is unlikely to malfunction when detecting the capacitance.

  A distance M1 is set between one long side of the extending portion 42a and the capacitance forming portion 41, and between the other long side of the extending portion 42c and the capacitance forming portion 41, and the extending portion 42b and the capacitance forming portion 41. The distance between the other short sides is the distance M2, and the length in the extending direction of each of the extending portions 42a and 42c is the length N. The ground electrode part 42 functions as a ground for a high-frequency signal by adjusting the distance M1 and the length N, and functions as if insulated from a DC voltage. The distance M1 and the length N also vary depending on the frequency to be countermeasured, the size of the capacitance forming unit 41, and the like.

  When the distance M1 is less than 0.6 mm, the detection circuit 20 may not be able to detect the capacitance. In that case, it is possible to prevent the capacitance from being detected by setting the distance M1 to 0.6 mm or more. The distance M1 is an example, and may be set as appropriate depending on conditions.

  By adjusting the length N of each of the extending portions 42a and 42c in the extending direction, the isolation of the ground electrode portion 42 can be adjusted. The length N also affects the detection sensitivity of the capacitance forming unit 41 (electrode pad 30), so that the length N is optimized so that the detection sensitivity of the capacitance forming unit 41 (electrode pad 30) is optimal. Adjust N.

  The specific numerical values of the distances M1 and M2 and the length N vary greatly depending on the material of the base material on which the pattern is drawn, such as the ground electrode portion 42 and the capacitance forming portion 41, and are desired to be removed. The frequency also changes. Therefore, as an example of a method of adjusting the distances M1 and M2 and the length N, a broadband frequency signal is input to the wiring 25, and as shown in FIG. The distances M1 and M2 and the length N are adjusted so as to be minimized.

  Thus, it is preferable that the ground electrode portion 42 has a shape in which SWR decreases in a frequency band including the frequency of a high-frequency signal input to the capacitance forming portion 41 from an external antenna or the like. Thereby, since the ground electrode part 42 functions as a ground in a frequency band including the frequency of the high-frequency signal, it is possible to suppress a high-frequency signal from being input to the capacitance forming part 41 from the outside.

  Furthermore, the ground electrode portion 42 preferably has a shape that minimizes the SWR with respect to the frequency of the high-frequency signal input from the outside. Thereby, since it functions as the ground most efficiently at the wavelength of the high frequency signal input from the outside, it is possible to more efficiently suppress the high frequency signal from being input to the capacitance forming unit 41 from the outside. .

[Summary]
The capacitance detection device 1 according to the first aspect of the present invention includes a capacitance forming unit 11 that forms a capacitance with an adjacent object, and a detection signal indicating that the capacitance has been detected. When the high-frequency signal is input to the detection circuit 20 to be output and the capacitance forming unit 11, the resonance is caused by the harmonic frequency superimposed on the detection signal, and is arranged in contact with the capacitance forming unit 11. And a resonating portion 13 that is provided.

  According to the above configuration, the resonance part is arranged in contact with the capacitance forming part. Thereby, the signal used as the unnecessary radiation input into the said capacitance formation part can be reduced. And the said resonance part resonates with the frequency of the harmonic superimposed on the said detection signal, when a high frequency signal is input into the said electrostatic capacitance formation part. Thereby, the harmonics superimposed on the detection signal due to the high-frequency signal, which is unnecessary radiation, can be reduced. For this reason, it can prevent malfunctioning when the said detection circuit detects the said electrostatic capacitance resulting from having input the said high frequency signal to the said electrostatic capacitance formation part. As a result, it is possible to obtain the capacitance detection device 1 that is unlikely to malfunction when detecting the capacitance.

  In the capacitance detection device 1 according to the second aspect of the present invention, in the first aspect, the resonance unit 13 has a shape in which the standing wave ratio (SWR) decreases in the frequency band F including the harmonic frequency. May be. According to the above configuration, since the resonance unit resonates in the frequency band F, the harmonics can be removed from the detection signal.

  The capacitance detection device 1A according to the aspect 3 of the present invention includes a capacitance forming unit 41 that forms a capacitance with an adjacent object, and a detection signal indicating that the capacitance has been detected. The output detection circuit 20 includes a ground electrode portion 42 that is separated from the capacitance forming portion 41 and surrounds the capacitance forming portion 41.

  According to the above configuration, the ground electrode portion is separated from the capacitance forming portion and surrounds the periphery of the capacitance forming portion. Thereby, the ground electrode portion can suppress an external high frequency signal from being input to the capacitance forming portion. Thereby, the harmonics superimposed on the detection signal due to the high-frequency signal, which is unnecessary radiation, can be reduced. For this reason, it can prevent malfunctioning when the said detection circuit detects the said electrostatic capacitance resulting from the said high frequency signal being input into the said electrostatic capacitance formation part. As a result, it is possible to obtain a capacitance detection device that is unlikely to malfunction when detecting the capacitance.

  In the electrostatic capacity detection device 1A according to aspect 4 of the present invention, in the aspect 3, the ground electrode part 42 is a standing wave in a frequency band including the frequency of the high frequency signal input to the electrostatic capacity forming part 41. A shape with a reduced ratio is preferred. According to the above configuration, since the ground electrode portion functions as a ground in a frequency band including the frequency of the high frequency signal, the high frequency signal can be prevented from being input to the capacitance forming portion from the outside. .

  A mobile information terminal (mobile phone terminal 50) according to aspect 5 of the present invention may include the capacitance detection devices 1 and 1A and an antenna for transmitting a high-frequency signal in the above aspects 1 to 4. Good. According to the above configuration, it is possible to obtain a portable information terminal that is unlikely to malfunction when the capacitance detection device detects the capacitance due to the high-frequency signal transmitted from the antenna.

The electrostatic capacitance detection device 1 according to the embodiment 6 of the present invention, in the above 2, the resonance frequency f ₀ of the resonance unit 13, the frequency of the standing wave ratio on the frequency of the harmonics (SWR) is minimum There may be. According to the above configuration, since the resonance unit resonates most strongly at the harmonic frequency, the harmonic can be more reliably removed from the detection signal.

  In the capacitance detection device 1 according to Aspect 7 of the present invention, in any one of Aspects 1, 2, and 6, the resonance unit 13 has one end connected to the capacitance formation unit 11 and the other end described above. You may have the trunk part 13a extended in the direction away from the electrostatic capacitance formation part 11, and the several branch part 13b which cross | intersects and contacts the said trunk part 13a. Thereby, the said resonance part can be obtained.

  The capacitance detection device 1 according to the eighth aspect of the present invention is the path (wiring 25) for connecting the capacitance forming unit 11 and the detection circuit 20 in any one of the first, second, sixth, and seventh aspects. And a circuit unit that includes at least one of the coil 2, the capacitor, and the diodes 3a and 3b. According to the above configuration, even when the high frequency signal input to the capacitance forming unit 11 resonates in the circuit unit and becomes a signal that is unnecessary radiation in the capacitance forming unit, it is the unnecessary radiation. The signal can be removed by the resonance unit.

  1 A of electrostatic capacitance detection apparatuses which concern on aspect 9 of this invention WHEREIN: It is preferable that the said ground electrode part 42 is a shape where a standing wave ratio becomes the minimum with respect to the wavelength of the said high frequency signal in the said aspect 4. FIG. According to the above configuration, since it functions as the ground most efficiently at the wavelength of the high-frequency signal, it is possible to more efficiently suppress the high-frequency signal from being input to the capacitance forming unit from the outside.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be used for a capacitance detection device that detects a capacitance and a portable information terminal.

1.1A: Capacitance detection device, 2: Coil, 3: Diode, 10: Sensor electrode part, 11: Capacitance formation part, 13: Resonance part, 13a: Trunk part, 13b: Branch part, 20: Detection circuit , 25: wiring, 41: capacitance forming portion, 42: ground electrode portion, 42a, 42b, 42c: extending portion, 50: mobile phone terminal (portable information terminal), 51: touch panel, 52: housing, M1. M2: distance, f ₀ : resonance frequency, F: frequency band

Claims (4)

A capacitance forming portion that forms a capacitance between the adjacent objects;
A detection circuit that outputs a detection signal indicating that the capacitance has been detected;
When a high-frequency signal, which is a transmission signal from an antenna, is input to the capacitance forming unit, it resonates with the harmonic frequency superimposed on the detection signal, and is arranged in contact with the capacitance forming unit. And a resonance part.   The capacitance detecting device according to claim 1, wherein the resonance unit has a shape in which a standing wave ratio decreases in a frequency band including the harmonic frequency. A capacitance forming portion that forms a capacitance between the adjacent objects;
A detection circuit that outputs a detection signal indicating that the capacitance has been detected;
Spaced apart from the capacitance forming portion, and, e Bei a ground electrode portion surrounding the periphery of the capacitance formation portion,
The electrostatic capacity detection device , wherein the ground electrode portion has a shape in which a standing wave ratio decreases in a frequency band including a frequency of a high-frequency signal input to the capacitance forming portion . The capacitance detection device according to any one of claims 1 to 3 ,
A portable information terminal comprising an antenna for transmitting a high-frequency signal.

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