Touch determination system

Abstract

This touch determination system comprises a self-excited vibrator, a detection unit, and a determination unit. The detection unit detects a vibration signal corresponding to the vibration of the vibrator. The determination unit determines, on the basis of a change in the amplitude of the vibration signal detected by the detection unit, the presence or absence of contact from the outside to an object. The determination unit further determines, on the basis of a change in the frequency of the vibration signal detected by the detection unit, the degree of pressure to the object due to the contact from the outside.

Description

Touch Detection System

[0001] TECHNICAL FIELD The present disclosure relates generally to touch determination systems, and more particularly to touch determination systems with self-excited oscillators.

[0002] Patent Literature 1 discloses a touch input detection system (touch determination system) as an example. The touch input detection system includes a first transmitter, a second transmitter, a receiver, and a processor that determines a touch input. The first transmitter transmits a first propagation signal to the receiver via a first propagation path. The second transmitter transmits a second propagation signal to the receiver via a second propagation path. The processor analyzes the first propagation signal and the second propagation signal and determines the touch input based on a determination that the first propagation path of the first propagation signal is obstructed by the touch input and the second propagation path of the second propagation signal is not obstructed by the touch input.

[0003] U.S. Pat. No. 10,296,144

[0004] The above touch input detection system can determine whether or not there is a touch input (e.g., contact with an object from the outside), but if the touch input is strong, for example, it is difficult to determine the degree of pressure of the touch input, that is, the degree of pressure applied to the object by external contact.

[0005] A touch determination system according to one aspect of the present disclosure includes a self-excited vibrator, a detection unit, and a determination unit. The detection unit detects a vibration signal corresponding to vibration of the vibrator. The determination unit determines whether or not an object has been touched from the outside based on a change in amplitude of the vibration signal detected by the detection unit. The determination unit further determines the degree of pressure on the object due to the external contact based on a change in frequency of the vibration signal detected by the detection unit.

[0006] According to the touch determination system according to an aspect of the present disclosure, it is possible to determine whether or not an object has been touched from the outside, and to determine the degree of pressure on the object due to the external contact.

[0007] FIG. 1 is an explanatory diagram of a touch decision system according to a first embodiment. FIG. 2 is a front view of a touch detection mechanism of the touch decision system. FIG. 3 is a waveform diagram of a drive voltage from an oscillator circuit, a down-converted signal, and a detection signal, relating to the touch decision system. FIG. 4 is a graph showing changes in amplitude and frequency of a vibration signal, relating to the touch decision system. FIG. 5 is a perspective view showing a part of an electronic device including the touch decision system. FIG. 6 is an explanatory diagram of a touch decision system according to a second embodiment. FIG. 7 is an explanatory diagram of a touch decision system according to a third embodiment. FIG. 8 is an explanatory diagram of a touch decision system according to a fourth embodiment. FIG. 9 is an explanatory diagram of a touch decision system according to a fifth embodiment. FIG. 10 is an explanatory diagram of a touch decision system according to a sixth embodiment.

[0008] Touch determination systems according to embodiments 1 to 6 will be described below with reference to the drawings. The figures described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0009] First Embodiment A touch determination system A1 according to a first embodiment will be described below with reference to FIGS.

[0010] (1) Touch Determination System As shown in FIG. 1 , the touch determination system A1 determines whether or not a person 100 has made contact (touched) with an object (in the example of FIG. 1 , the housing 90 described below). In short, the touch determination system A1 determines whether or not the object has been touched from the outside. The touch determination system A1 includes, for example, a touch detection mechanism B1, an oscillation unit 20, a detection unit 2, a control device 3, and a temperature sensor 9. Note that in this embodiment, the external contact with the object is assumed to be contact with the finger of the person 100. However, this is not limited to contact with the finger of the person 100, and may also be contact when using a touch pen (e.g., an aluminum touch pen), for example. In short, the external contact with the object includes not only direct contact by the person 100, but also indirect contact by the person 100.

[0011] (2) Components of the Touch Determination System (2.1) Touch Detection Mechanism The touch detection mechanism B1 is a touch detection mechanism for detecting contact with the object from the outside. As shown in FIG. 1 , the touch detection mechanism B1 has a frame body 40, a pair of fixing portions 50, and a pair of groove portions 60.

[0012] The frame body 40 propagates vibrations of the resonator 1 (described later) in the oscillation section 20. The frame body 40 is, for example, a rectangular frame. The frame body 40 is made of, for example, metal. As shown in FIG. 2 , the frame body 40 includes an attachment section 41, a pressure receiving section 42, a pair of transmission sections 43, and a pair of support sections 44. The frame body 40 has a structure in which the pair of support sections 44 support the attachment section 41 at both ends (a double-support structure).

[0013] The vibrator 1 is attached to the attachment portion 41. The attachment portion 41 vibrates in response to the vibration of the vibrator 1. The attachment portion 41 is, for example, plate-shaped (for example, rectangular plate-shaped). The attachment portion 41 is, for example, rectangular in plan view. The vibrator 1 is attached to one surface of the attachment portion 41. The vibrator 1 is attached to the above-mentioned one surface of the attachment portion 41 via an insulating sheet. The insulating sheet has electrical insulating properties.

[0014] The pressure receiving portion 42 receives pressure P1 (see FIG. 1 ) on the object due to external contact. In other words, the pressure receiving portion 42 deforms in response to pressure P1 on the object due to external contact. The pressure receiving portion 42 is, for example, plate-shaped (e.g., rectangular plate-shaped). The pressure receiving portion 42 is, for example, rectangular in plan view. As described above, vibrations of the vibrator 1 propagate to the frame 40, and the frame 40 deforms in response to pressure P1 on the object. In this way, the vibrator 1 is configured to be mechanically coupled to the object via the frame 40. The frame 40 is an intermediary that mechanically couples the vibrator 1 to the object, propagates vibrations of the vibrator 1, and is deformable in response to pressure on the object.

[0015] The pair of transmission portions 43 includes a first transmission portion 43a and a second transmission portion 43b. The first transmission portion 43a transmits vibrations of the mounting portion 41 to the pressure receiving portion 42 and transmits stress corresponding to the pressure P1 received by the pressure receiving portion 42 to the mounting portion 41. The first transmission portion 43a is, for example, shaped like a column (a right-angled triangular column in the example of FIG. 2). The first transmission portion 43a has a first acute-angle portion 8a and a second acute-angle portion 8b. Note that the "stress corresponding to the pressure P1 received by the pressure receiving portion 42" refers to a force generated by the deformation of the pressure receiving portion 42 when the pressure receiving portion 42 deforms in response to the pressure P1 applied to the object due to external contact.

[0016] Similar to the first transmitting portion 43a, the second transmitting portion 43b transmits the vibration of the mounting portion 41 to the pressure receiving portion 42, and also transmits the stress corresponding to the pressure P1 received by the pressure receiving portion 42 to the mounting portion 41. The second transmitting portion 43b has, for example, a columnar shape (a right-angled triangular prism shape in the example of FIG. 2). Similar to the first transmitting portion 43a, the second transmitting portion 43b has a first acute angle portion 8a and a second acute angle portion 8b.

[0017] The pair of support portions 44 includes a first support portion 44a and a second support portion 44b. The first support portion 44a connects the mounting portion 41 and the pressure receiving portion 42 and supports the transmission portion 43. More specifically, the first support portion 44a connects a first end (the left end in the example of FIG. 2 ) of the mounting portion 41 to a first end (the left end in the example of FIG. 2 ) of the pressure receiving portion 42 and supports the first transmission portion 43a. The first support portion 44a is, for example, plate-shaped (e.g., rectangular plate-shaped). The first acute angle portion 8a of the first transmission portion 43a is connected to the first support portion 44a. The second acute angle portion 8b of the first transmission portion 43a is connected to the pressure receiving portion 42. The bending rigidity of the first support portion 44a is higher than the bending rigidity of the mounting portion 41.

[0018] Note that "bending rigidity" is a physical quantity expressed, for example, by the product of the Young's modulus of the material of the mounting portion 41 and the second moment of area of ​​the mounting portion 41. For example, when the cross-sectional shape of the mounting portion 41 is rectangular, the second moment of area is expressed by the following (Equation 1). I in (Equation 1) represents the second moment of area. Also, b in (Equation 1) represents the width (width dimension) of the cross-section of the object. Also, h in (Equation 1) represents the height (height dimension) of the cross-section of the object.

[0019] I = b h ３ / 12 ... (Equation 1) The second support portion 44b connects the mounting portion 41 and the pressure receiving portion 42 and supports the transmission portion 43. More specifically, the second support portion 44b connects the second end (the right end in the example of FIG. 2) of the mounting portion 41 and the second end (the right end in the example of FIG. 2) of the pressure receiving portion 42 and supports the second transmission portion 43b. The second support portion 44b is, for example, plate-shaped (e.g., rectangular plate-shaped). The first acute angle portion 8a of the second transmission portion 43b is connected to the second support portion 44b. The second acute angle portion 8b of the second transmission portion 43b is connected to the pressure receiving portion 42. The bending rigidity of the second support portion 44b is higher than the bending rigidity of the mounting portion 41. Furthermore, the bending rigidity of the second support portion 44b is the same as the bending rigidity of the first support portion 44a. Note that the phrase "the bending rigidity of the second support portion 44b is the same as the bending rigidity of the first support portion 44a" does not only mean that the bending rigidity of the second support portion 44b and the bending rigidity of the first support portion 44a are exactly the same, but also means that the difference between the bending rigidity of the second support portion 44b and the bending rigidity of the first support portion 44a (the absolute value of the difference) is equal to or less than a first predetermined value. For example, it also means that the difference between the bending rigidity of the second support portion 44b and the bending rigidity of the first support portion 44a is about 10% of the bending rigidity of the first support portion 44a.

[0020] The vibration frequency of the mounting portion 41 changes in response to the stress corresponding to the pressure P1 received by the pressure-receiving portion 42. More specifically, the vibration frequency of the mounting portion 41 changes in response to the stress applied to the pair of support portions 44 (the first support portion 44a and the second support portion 44b) via the pair of propagation portions 43 (the first propagation portion 43a and the second propagation portion 43b). More specifically, the pair of support portions 44 are displaced due to the stress applied to the pair of support portions 44, and the vibration frequency of the mounting portion 41 changes in response to the tension generated in the mounting portion 41 due to the displacement of the pair of support portions 44.

[0021] The pair of fixing portions 50 includes a first fixing portion 50a and a second fixing portion 50b. The first fixing portion 50a fixes the frame body 40. More specifically, the first fixing portion 50a fixes the frame body 40 by holding the first support portion 44a of the frame body 40. The second fixing portion 50b fixes the frame body 40. More specifically, the second fixing portion 50b fixes the frame body 40 by holding the second support portion 44b of the frame body 40. In short, the pair of fixing portions 50 (the first fixing portion 50a and the second fixing portion 50b) fixes the frame body 40 by holding the pair of support portions 44 (the first support portion 44a and the second support portion 44b).

[0022] The first fixing portion 50a is, for example, columnar (e.g., rectangular columnar). The first fixing portion 50a is connected to one end (the lower end in the example of FIG. 2 ) of the first support portion 44a and a first end (the left end in the example of FIG. 2 ) of the pressure-receiving portion 42. The second fixing portion 50b is, for example, columnar (e.g., rectangular columnar). The second fixing portion 50b is connected to one end (the lower end in the example of FIG. 2 ) of the second support portion 44b and a second end (the right end in the example of FIG. 2 ) of the pressure-receiving portion 42.

[0023] The first fixing portion 50a has a first hole 51a through which a first fixing member is inserted. The first fixing member is a member for fixing the first fixing portion 50a to the housing 90. The second fixing portion 50b has a second hole 51b through which a second fixing member is inserted. The second fixing member is a member for fixing the second fixing portion 50b to the housing 90. The first fixing member and the second fixing member are, for example, screws. Note that the first fixing member and the second fixing member are not limited to screws and may be, for example, bosses (protrusions) for crimping.

[0024] The pair of grooves 60 includes a first groove 60a and a second groove 60b. The first groove 60a is provided between the first fixing portion 50a and the first support portion 44a. The first groove 60a has a U-shape when viewed from the front of the frame 40. The second groove 60b is provided between the second fixing portion 50b and the second support portion 44b. The second groove 60b has a U-shape when viewed from the front of the frame 40.

[0025] (2.2) Oscillator Section The oscillator section 20 shown in FIG. 1 includes, for example, a vibrator 1, an oscillator circuit 10, and a buffer amplifier 11.

[0026] The vibrator 1 is, for example, a piezoelectric element including a piezoelectric body. The vibrator 1 has a pair of electrodes 21 and one feedback electrode 38. The pair of electrodes 21 are electrically connected to an oscillation circuit 10. The feedback electrode 38 is also electrically connected to the oscillation circuit 10. In other words, the vibrator 1 is connected to the oscillation circuit 10. The oscillation circuit 10 is a self-oscillating circuit that includes an oscillation unit that is connected to the vibrator 1 and self-oscillates, and an amplifier unit that amplifies a frequency signal oscillated by the oscillation unit and feeds the amplified frequency signal back to the oscillation unit via the feedback electrode 38. The vibrator 1 is also a self-excited vibrator. Note that a "self-excited vibrator" refers to a vibrator that self-oscillates at the resonant frequency of the vibrator in response to a drive voltage from the oscillation circuit.

[0027] The oscillator circuit 10 is, for example, a Colpitts oscillator circuit. The oscillator circuit 10 is electrically connected to the vibrator 1. The oscillator circuit 10 is also electrically connected to the detector 2 via a buffer amplifier 11.

[0028] The oscillator circuit 10 supplies a drive voltage V1 (see FIG. 3 ) to the vibrator 1. The oscillator circuit 10 also outputs a vibration signal S1 corresponding to the vibration of the vibrator 1 to the detector 2 via a buffer amplifier 11. In other words, the vibrator 1 outputs the vibration signal S1 corresponding to the vibration of the vibrator 1 itself to the detector 2. The vibration signal S1 is, for example, a sinusoidal signal (analog signal). The frequency of the vibration signal S1 is, for example, within a range of 18 kHz to 1 MHz. In other words, the vibration frequency of the vibrator 1 is, for example, within a range of 18 kHz to 1 MHz.

[0029] (2.3) Detector The detector 2 detects the vibration signal S1 from the oscillator 20 (specifically, the vibrator 1). The detector 2 includes, for example, a frequency detector 18 and an amplitude detector 19.

[0030] The frequency detector 18 detects the frequency of the vibration signal S1 and includes, for example, a PLL (Phase Locked Loop) multiplier circuit 5 and a frequency counter 4.

[0031] The PLL multiplier circuit 5 multiplies the frequency of the vibration signal S1. Specifically, the PLL multiplier circuit 5 converts the frequency of the vibration signal S1 (hereinafter sometimes referred to as the "first frequency") to a frequency (second frequency) that is N times (N≧2) the frequency, and outputs a signal (multiplied signal) S3 including the second frequency to the frequency counter 4. In other words, the second frequency is a frequency higher than the first frequency. For example, the PLL multiplier circuit 5 converts the first frequency of the vibration signal S1 to a frequency (second frequency) that is 10 times the frequency of the vibration signal S1. The first frequency is, for example, 30 kHz. The second frequency is, for example, 300 kHz.

[0032] The PLL multiplier circuit 5 includes, for example, a waveform shaper 12 , a phase comparator 13 , a charge pump 14 , a loop filter 15 , a VCO (Voltage Controlled Oscillator) 16 , and a frequency divider 17 .

[0033] The waveform shaper 12 shapes the vibration signal S1 from the oscillation unit 20 into a pulsed signal (pulse signal) S2 and outputs the pulse signal S2 to the phase comparator 13. The waveform shaper 12 is electrically connected to the output terminal of the buffer amplifier 11 of the oscillation unit 20. The waveform shaper 12 is also electrically connected to the phase comparator 13. The frequency of the pulse signal S2 is the same as the frequency of the vibration signal S1. Note that "the frequency of the pulse signal S2 is the same as the frequency of the vibration signal S1" does not only mean that the frequencies of the pulse signal S2 and the vibration signal S1 are completely the same, but also means that, for example, the difference between the frequencies of the pulse signal S2 and the vibration signal S1 (the absolute value of the difference) is equal to or less than a second predetermined value. For example, it also means that the difference between the frequencies of the pulse signal S2 and the vibration signal S1 is approximately 5% of the frequency of the vibration signal S1.

[0034] The phase comparator 13 outputs a voltage (differential voltage) corresponding to the phase difference between the pulse signal S2 from the waveform shaper 12 and a frequency-divided signal S5 (described later) to the charge pump 14. The phase comparator 13 is electrically connected to the waveform shaper 12. The phase comparator 13 is also electrically connected to the charge pump 14. The phase comparator 13 is also electrically connected to the frequency divider 17.

[0035] The charge pump 14 boosts the differential voltage from the phase comparator 13 and outputs the boosted voltage (boosted voltage) to the loop filter 15. The charge pump 14 is electrically connected to the phase comparator 13. The charge pump 14 is also electrically connected to the loop filter 15.

[0036] The loop filter 15 smoothes the boosted voltage from the charge pump 14 and outputs the smoothed voltage to the VCO 16. The loop filter 15 is electrically connected to the charge pump 14. The loop filter 15 is also electrically connected to the VCO 16.

[0037] The VCO 16 outputs a multiplied signal S3 corresponding to the smoothed voltage from the loop filter 15 to the frequency counter 4. The VCO 16 also outputs the multiplied signal S3 to the frequency divider 17. The VCO 16 is electrically connected to the loop filter 15. The VCO 16 is also electrically connected to the frequency counter 4. The VCO 16 is also electrically connected to the frequency divider 17.

[0038] The frequency divider 17 divides the second frequency of the multiplied signal S3 from the VCO 16. Specifically, the frequency divider 17 converts the second frequency of the multiplied signal S3 to a frequency (third frequency) that is 1 / N times the frequency of the multiplied signal S3 and outputs a signal (frequency-divided signal) S5 including the third frequency to the phase comparator 13. In other words, the third frequency is a frequency lower than the second frequency. For example, the frequency divider 17 converts the second frequency of the multiplied signal S3 to a frequency (third frequency) that is 1 / 10 times the frequency of the multiplied signal S3. The third frequency is, for example, 30 kHz. The frequency division value (1 / N value) of the frequency divider 17 is preset, for example, by the control device 3 (more specifically, the control unit 6 described below).

[0039] The frequency counter 4 measures the second frequency of the multiplied signal S3 by counting the rising edges or falling edges of the multiplied signal S3 from the PLL multiplier circuit 5 for a certain period of time. In other words, the frequency counter 4 measures the second frequency corresponding to the frequency of the vibration signal S1. The frequency counter 4 is electrically connected to the PLL multiplier circuit 5. The frequency counter 4 is also electrically connected to the control device 3.

[0040] The amplitude detector 19 detects the amplitude of the vibration signal S1. The amplitude detector 19 includes, for example, a downconverter 35, a local oscillator 28, and a digital signal processor 27.

[0041] The downconverter 35 downconverts the frequency of the vibration signal S1. Specifically, the downconverter 35 converts the first frequency of the vibration signal S1 to a predetermined frequency (fourth frequency) and outputs a signal (downconverted signal) S4 including the fourth frequency to the digital signal processing unit 27. The fourth frequency is lower than the first frequency. The fourth frequency is, for example, 1 kHz. More specifically, the fourth frequency is, for example, a frequency within a range of 1 kHz ±5%. Note that the fourth frequency is not limited to a frequency within a range of 1 kHz ±5%, and may be any frequency at which a change in the amplitude of the vibration signal S1 (more specifically, the detection signal K1 described below) can be easily detected.

[0042] The downconverter 35 includes, for example, a filter 22, a buffer amplifier 23, a pair of mixers 24a and 24b, a pair of filters 25a and 25b, a pair of ADCs (Analog to Digital Converters) 26a and 26b, and a 90-degree splitter 29. The pair of mixers 24a and 24b includes a first mixer 24a and a second mixer 24b. The pair of filters 25a and 25b includes a first filter 25a and a second filter 25b. The pair of ADCs 26a and 26b includes a first ADC 26a and a second ADC 26b.

[0043] The filter 22 removes noise components from the vibration signal S1 from the oscillator 20. The filter 22 is electrically connected to the output terminal of the buffer amplifier 11 of the oscillator 20. The filter 22 is also electrically connected to the first mixer 24 a and the second mixer 24 b via the buffer amplifier 23.

[0044] The first mixer 24a outputs to the first filter 25a a signal (first differential signal) including a difference (absolute value of the difference) between the frequency of the vibration signal S1 and the frequency of a first signal, described below, from the 90-degree divider 29. A first input terminal of the first mixer 24a is electrically connected to the output terminal of the buffer amplifier 23. A second input terminal of the first mixer 24a is electrically connected to the 90-degree divider 29. An output terminal of the first mixer 24a is electrically connected to the first filter 25a.

[0045] The second mixer 24b outputs to the second filter 25b a signal (second difference signal) including a difference (absolute value of the difference) between the frequency of the vibration signal S1 and the frequency of a second signal (described later) from the 90-degree divider 29. A first input terminal of the second mixer 24b is electrically connected to the output terminal of the buffer amplifier 23. A second input terminal of the second mixer 24b is electrically connected to the 90-degree divider 29. An output terminal of the second mixer 24b is electrically connected to the second filter 25b.

[0046] The first filter 25a removes noise components from the first differential signal from the first mixer 24a. The first filter 25a is electrically connected to the first mixer 24a. The first filter 25a is also electrically connected to the first ADC 26a. The second filter 25b removes noise components from the second differential signal from the second mixer 24b. The second filter 25b is electrically connected to the second mixer 24b. The second filter 25b is also electrically connected to the second ADC 26b.

[0047] The first ADC 26a converts the first differential signal, which is an analog signal, into a digital signal. The first ADC 26a outputs the converted first differential signal to the digital signal processing unit 27. The first ADC 26a is electrically connected to the first filter 25a. The first ADC 26a is also electrically connected to the second ADC 26b. The first ADC 26a is also electrically connected to the digital signal processing unit 27.

[0048] The second ADC 26b converts the second differential signal, which is an analog signal, into a digital signal. The second ADC 26b outputs the converted digital second differential signal to the digital signal processing unit 27. The second ADC 26b is electrically connected to the second filter 25b. The second ADC 26b is also electrically connected to the first ADC 26a. The second ADC 26b is also electrically connected to the digital signal processing unit 27.

[0049] The 90-degree divider 29 generates a signal (first signal) that is the local signal S11 as is and a signal (second signal) that is the local signal S11 out of phase by 90 degrees, based on a local signal S11 (described later) from the local oscillator 28. The 90-degree divider 29 outputs the first signal to the first mixer 24a and the second signal to the second mixer 24b, for example. The 90-degree divider 29 is electrically connected to the local oscillator 28. The 90-degree divider 29 is also electrically connected to the first mixer 24a. The 90-degree divider 29 is also electrically connected to the second mixer 24b.

[0050] The local oscillator 28 outputs a local signal S11 based on the frequency measured by the frequency counter 4. More specifically, the local oscillator 28 outputs the local signal S11 based on a control signal S10 (described later) from the control device 3. The local signal S11 is a signal for down-converting the frequency of the vibration signal S1. In other words, the local signal S11 is a signal for converting the first frequency of the vibration signal S1 to a fourth frequency. The local oscillator 28 is electrically connected to the control device 3. The local oscillator 28 is also electrically connected to a 90-degree divider 29.

[0051] The downconverter 35 converts the first frequency of the vibration signal S1 to a fourth frequency in accordance with the local signal S11 from the local oscillator 28, and outputs the downconverted signal S4 to the digital signal processing unit 27. Specifically, the downconverter 35 outputs a signal obtained by adding the first differential signal from the first ADC 26 a and the second differential signal from the second ADC 26 b to the digital signal processing unit 27 as the downconverted signal S4.

[0052] The digital signal processing unit 27 processes the down-converted signal S4 from the down-converter 35 and outputs a detection signal K1 to the control device 3. For example, as shown in FIG. 3 , the digital signal processing unit 27 detects the envelope of the down-converted signal S4 and outputs the detected envelope as a detection signal K1 to the control device 3. The digital signal processing unit 27 is electrically connected to the down-converter 35. The digital signal processing unit 27 is also electrically connected to the control device 3. The frequency of the detection signal K1 is the same as the fourth frequency of the down-converted signal S4.

[0053] Note that "the frequency of the detection signal K1 is the same as the fourth frequency of the downconverted signal S4" does not necessarily mean that the frequency of the detection signal K1 and the fourth frequency of the downconverted signal S4 are completely the same. It also means, for example, that the difference (absolute value of the difference) between the frequency of the detection signal K1 and the fourth frequency of the downconverted signal S4 is equal to or less than a third predetermined value. For example, it also means that the difference between the frequency of the detection signal K1 and the fourth frequency of the downconverted signal S4 is approximately 5% of the fourth frequency of the downconverted signal S4. The waveforms of the downconverted signal S4 and the detection signal K1 in FIG. 3 are illustrated schematically and may differ from the actual waveforms. Furthermore, the downconverted signal S4 and the detection signal K1 in FIG. 3 are illustrated as analog signals to facilitate understanding of the description of the embodiment. Here, the digital signal in this embodiment is a signal obtained by quantizing a discrete signal, not a signal coded into binary digits of "0" and "1."

[0054] (2.4) Control Device The control device 3 shown in FIG. 1 is realized, for example, by a computer system having one or more processors and one or more memories. That is, the functions of the control device 3 are realized by the one or more processors executing a program stored in the memory. The program may be pre-stored in the memory, provided via a telecommunications line such as the Internet, or provided by being recorded on a non-transitory recording medium such as a memory card. The control device 3 includes, for example, a control unit 6 and a determination unit 7. The control unit 6 is electrically connected to the PLL multiplication circuit 5 and the frequency counter 4. The control unit 6 is also electrically connected to the downconverter 35, the local oscillator 28, and the digital signal processing unit 27. The determination unit 7 is electrically connected to the frequency counter 4 and the digital signal processing unit 27.

[0055] The control unit 6 controls, for example, the detection unit 2 (the frequency detection unit 18 and the amplitude detection unit 19). More specifically, the control unit 6 controls, for example, the PLL multiplication circuit 5 and the frequency counter 4. The control unit 6 also controls, for example, the downconverter 35, the local oscillator 28, and the digital signal processing unit 27. The control unit 6 also outputs a signal (control signal) S10 including information on the frequency measured by the frequency counter 4 to the local oscillator 28. When the frequency measured by the frequency counter 4 changes, the control unit 6 also outputs a control signal S10 including information on the changed frequency to the local oscillator 28.

[0056] The determination unit 7 determines whether or not there is external contact with the object based on a change in the amplitude of the vibration signal S1 detected by the detection unit 2. More specifically, the determination unit 7 determines whether or not there is external contact with the object based on a change in the amplitude of the detection signal K1 corresponding to the vibration signal S1. Specifically, the determination unit 7 determines whether or not there is external contact with the object based on a comparison result between the amplitude of the detection signal K1 and a threshold value Vt1 (see FIG. 3 ) during a period in which the amplitude value of the detection signal K1 from the amplitude detection unit 19 is constant (e.g., period T3 in FIG. 3 ). For example, if the amplitude of the detection signal K1 changes, the determination unit 7 determines that there is external contact with the object. On the other hand, if the amplitude of the detection signal K1 does not change, the determination unit 7 determines that there is no external contact with the object. The threshold value Vt1 is pre-stored in the memory of the control device 3. Time points t1 and t3 in Fig. 3 represent the times when the vibrator 1 starts self-oscillation (time points when the oscillation circuit 10 starts outputting the drive voltage V1). Time points t2 and t4 in Fig. 3 represent the times when the vibrator 1 stops self-oscillation (time points when the oscillation circuit 10 stops outputting the drive voltage V1). Period T1 in Fig. 3 represents the period during which the vibrator 1 continues self-oscillation (oscillation period of the vibrator 1). Period T2 in Fig. 3 represents the period during which the vibrator 1 stops self-oscillation and reverberation is generated by the vibrator 1 (reverberation period of the vibrator 1). Period T3 in Fig. 3 represents the period during which the oscillation of the vibrator 1 is stable (stable period of the vibrator 1).

[0057] Here, the period during which the amplitude value of the amplitude of the detection signal K1 is a constant value (stable period T3 of the vibrator 1) can be determined, for example, by measuring in advance the period (hereinafter referred to as the "standby period") from the time when the vibrator 1 starts self-oscillation (for example, time t1 in Figure 3) to the time when the amplitude value of the amplitude of the detection signal K1 becomes a constant value (in the example of Figure 3, the start time of the stable period T3 of the vibrator 1), and subtracting the above-mentioned standby period from the vibration period T1 of the vibrator 1.

[0058] The standby period is not limited to the period from when the vibrator 1 starts self-oscillation to when the amplitude of the detection signal K1 reaches a constant value, but may be, for example, any time within the stable period T3 after the time when the vibrator 1 starts self-oscillation and when the amplitude of the detection signal K1 reaches a constant value (for example, a time within the first half of the stable period T3). In other words, the standby period may be a predetermined period, i.e., a period with a margin added, measured in advance. The standby period is stored in the memory of the control device 3.

[0059] Furthermore, the determination unit 7 determines the degree of pressure P1 on the object due to external contact (the degree of external pressure or the magnitude of pressure P1) based on a change in the frequency of the vibration signal S1 detected by the detection unit 2. More specifically, the determination unit 7 determines the degree of pressure P1 based on a change in the frequency measured by the frequency counter 4. For example, if the frequency measured by the frequency counter 4 changes after determining that the object has been contacted from the outside (in the example of FIG. 4 , if the vibration frequency of the vibrator 1 increases), the determination unit 7 determines that the degree of pressure P1 is large (a state in which pressure P1 is strong). On the other hand, if the frequency measured by the frequency counter 4 does not change after determining that the object has been contacted from the outside, the determination unit 7 determines that the degree of pressure P1 is small (a state in which pressure P1 is weak). Note that a state in which pressure P1 is weak is assumed to be, for example, a state in which the finger of the person 100 is lightly touching the object. Furthermore, a state in which pressure P1 is strong is assumed to be a state in which the object is pressed by the finger of person 100, for example. Frequency f0 in Fig. 4 represents the vibration frequency of vibrator 1. Waveform k1 in Fig. 4 represents a waveform in a state in which there is no external contact with the object. Waveform k2 in Fig. 4 represents a waveform in a state in which pressure P1 is weak. Waveform k3 in Fig. 4 represents a waveform in a state in which pressure P1 is strong.

[0060] 1 preferably controls the detection unit 2 to stop the operation of the frequency counter 4 and the PLL multiplication circuit 5 when the determination unit 7 determines that there is no external contact with the object. Also, the control unit 6 preferably controls the detection unit 2 to operate the frequency counter 4 and the PLL multiplication circuit 5 when the determination unit 7 determines that there is external contact with the object. As a result, in the touch determination system A1, when there is no external contact with the object, the operation of the frequency counter 4 and the PLL multiplication circuit 5 stops, and therefore power consumption can be reduced compared to when the frequency counter 4 and the PLL multiplication circuit 5 are operating.

[0061] (2.5) Temperature Sensor The temperature sensor 9 detects the ambient temperature of the vibrator 1. The temperature sensor 9 is electrically connected to the control unit 6.

[0062] The control unit 6 corrects the amplitude and frequency of the vibration signal S1 based on the temperature detected by the temperature sensor 9 (ambient temperature of the vibrator 1). For example, when the ambient temperature of the vibrator 1 is 40°C, the control unit 6 corrects the amplitude and frequency of the vibration signal S1 so that they become the amplitude and frequency of the vibration signal S1 when the ambient temperature of the vibrator 1 is room temperature (e.g., 25°C ± 3°C). The control unit 6 corrects the amplitude and frequency of the vibration signal S1 based on, for example, a data table in which the ambient temperature of the vibrator 1 is associated with the amplitude and frequency of the vibration signal S1. The data table is, for example, stored in advance in the memory of the control device 3. Note that in this embodiment, the amplitude of the vibration signal S1 corrected by the control unit 6 is the amplitude of the detection signal K1. Furthermore, the frequency of the vibration signal S1 corrected by the control unit 6 is the frequency measured by the frequency counter 4.

[0063] The touch determination system A1 is used in an electronic device C1 such as a mobile device (for example, a smartphone or a tablet terminal) as shown in FIG. 5, for example.

[0064] The electronic device C1 includes, for example, a touch determination system A1 having a plurality of touch detection mechanisms B1 (two in the example of FIG. 5 ), and a housing 90. The plurality of touch detection mechanisms B1 include a first touch detection mechanism B11 and a second touch detection mechanism B12. The first touch detection mechanism B11 and the second touch detection mechanism B12 are attached to the housing 90. Note that the control device 3 is not illustrated in FIG. 5 . The number of control devices 3 may be multiple or may be one. Furthermore, the plurality of touch detection mechanisms B1 include the second fixing portion 50b of the first touch detection mechanism B11 and the first fixing portion 50a of the second touch detection mechanism B12 as one shared fixing portion 50. In other words, the first touch detection mechanism B11 and the second touch detection mechanism B12 are partially coupled, and, for example, the first fixing portion 50a of the second touch detection mechanism B12 utilizes the second fixing portion 50b of the first touch detection mechanism B11. This allows the touch determination system A1 in the electronic device C1 to be miniaturized.

[0065] The housing 90 is, for example, in the shape of a box (for example, a rectangular box) with one side open. The housing 90 is also rectangular in plan view. The material of the housing 90 is, for example, metal. The multiple touch detection mechanisms B1 are arranged on a side wall 91 of the housing 90, for example, as shown in FIG. 5 . More specifically, the multiple touch detection mechanisms B1 are arranged side by side along one direction (the longitudinal direction of the housing 90 in the example of FIG. 5 ) of one surface 91 a (the inner surface of the side wall 91) of the side wall 91 of the housing 90.

[0066] (3) Effects As shown in Fig. 1, the touch determination system A1 includes a self-excited vibrator 1, a detection unit 2, and a determination unit 7. The determination unit 7 determines whether or not the object has been touched from the outside based on a change in the amplitude of the vibration signal S1 detected by the detection unit. The determination unit 7 also determines the level of pressure P1 on the object due to the external contact based on a change in the frequency of the vibration signal S1. This allows the touch determination system A1 to determine whether or not the object has been touched from the outside, as well as to determine the level of pressure P1 on the object due to the external contact.

[0067] The detection unit 2 also has a frequency counter 4. The determination unit 7 determines the degree of pressure P1 based on a change in the frequency measured by the frequency counter 4. As a result, in the touch determination system A1, the configuration of the detection unit 2 (more specifically, the frequency detection unit 18) can be simplified compared to, for example, a case in which the frequency counter 4 is not used and a frequency detection circuit that detects the frequency of the multiplied signal S3 based on the multiplied signal S3 from the PLL multiplication circuit 5 and a reference signal is used.

[0068] The detection unit 2 also includes a PLL multiplication circuit 5. The frequency counter 4 measures the frequency (second frequency) multiplied by the PLL multiplication circuit 5. That is, the frequency counter 4 measures the second frequency, which is higher than the frequency (first frequency) of the vibration signal S1. Therefore, the frequency counter 4 can measure the second frequency multiplied by the PLL multiplication circuit 5 faster than when measuring the first frequency of the vibration signal S1. As a result, the touch determination system A1 can measure the second frequency corresponding to the frequency of the vibration signal S1 faster, and therefore can detect the frequency of the vibration signal S1 more quickly than when the detection unit 2 does not include the PLL multiplication circuit 5.

[0069] The detection unit 2 also includes a downconverter 35 and a local oscillator 28. The local oscillator 28 outputs a local signal S11 to the downconverter 35 based on the frequency (second frequency) measured by the frequency counter 4. The downconverter 35 downconverts the frequency of the vibration signal S1 in accordance with the local signal S11. The determination unit 7 determines whether or not the object has been touched from the outside based on a change in amplitude of a downconverted signal S4 including the frequency (fourth frequency) downconverted by the downconverter 35. As a result, in the touch determination system A1, the control unit 6 can adjust the frequency of the local signal S11 output from the local oscillator 28. Furthermore, since the touch determination system A1 can adjust the frequency of the local signal S11, the frequency downconverted by the downconverter 35 (the fourth frequency of the downconverted signal S4) can be stabilized. Therefore, in the touch determination system A1, narrow-band filters can be used, for example, as the first filter 25a and the second filter 25b. Furthermore, in the touch determination system A1, the fourth frequency of the down-converted signal S4 can be stabilized, and therefore the accuracy (determination accuracy) of determining whether or not the object has been touched from the outside can be improved.

[0070] The touch determination system A1 also includes a temperature sensor 9. The control unit 6 corrects the amplitude and frequency of the vibration signal S1 based on the temperature (ambient temperature of the vibrator 1) detected by the temperature sensor 9. As a result, the touch determination system A1 can reduce the influence of the ambient temperature of the vibrator 1, determine whether or not the object has been touched from the outside, and determine the degree of pressure P1 on the object due to the external contact.

[0071] The touch determination system A1 includes a frame 40. The frame 40 includes an attachment portion 41, a pressure receiving portion 42, and a pair of transmission portions 43. The vibration frequency of the attachment portion 41 changes depending on the stress corresponding to the pressure P1 received by the pressure receiving portion 42. As a result, in the touch determination system A1, the stress is transmitted to the attachment portion 41 via the pair of transmission portions 43, so that the touch determination system A1 can determine whether or not the object has been touched from the outside. Furthermore, in the touch determination system A1, the stress is transmitted to the attachment portion 41 via the pair of transmission portions 43, and the vibration frequency of the attachment portion 41 changes depending on the magnitude of the stress, so that the degree of the pressure P1 applied to the object due to the external contact can be determined. Therefore, the touch determination system A1 can determine whether or not the object has been touched from the outside, and can also determine the degree of the pressure P1 applied to the object due to the external contact.

[0072] Furthermore, the frame 40 includes a pair of support portions 44, and the bending rigidity of the pair of support portions 44 is higher than the bending rigidity of the attachment portion 41. The vibration frequency of the attachment portion 41 changes in accordance with the stress applied to the pair of support portions 44 via the pair of propagation portions 43. As a result, in the touch determination system A1, the stress is more easily transmitted to the attachment portion 41 than in a case where the bending rigidity of the pair of support portions 44 is lower than the bending rigidity of the attachment portion 41, and the accuracy (determination accuracy) of determining the degree of pressure P1 applied to the object due to external contact can be improved.

[0073] The electronic device C1 includes a touch determination system A1 and a housing 90. This allows the electronic device C1 to determine whether or not the object is being touched from the outside, and to determine the degree of pressure P1 on the object due to the external contact.

[0074] (4) Modification The determination unit 7 shown in FIG. 1 determines whether or not there is external contact with the object based on the comparison result between the amplitude value of the detection signal K1 and the threshold value Vt1 (see FIG. 3) during the stable period T3 of the vibrator 1 (see FIG. 3). However, for example, when the vibrator 1 stops self-oscillation (at time t2 in the example of FIG. 3), it may also determine whether or not there is external contact with the object based on the comparison result between the amplitude value of the detection signal K1 and the threshold value Vt1.

[0075] The determination unit 7 determines whether or not there is external contact with the object based on the comparison result between the amplitude of the detection signal K1 and the threshold value Vt1 during the stable period T3 of the vibrator 1. However, the determination unit 7 may also determine whether or not there is external contact with the object based on the comparison result between the amplitude of the detection signal K1 and the threshold value during, for example, a period after the vibrator 1 stops self-oscillation (in the example of FIG. 3 , the reverberation period T2 of the vibrator 1). In this case, the threshold value compared with the amplitude of the detection signal K1 is a value when there is no external contact with the object and is smaller than the threshold value Vt1. The timing for comparing the amplitude of the detection signal K1 with the threshold value is preferably close to the time when the vibrator 1 stops self-oscillation (for example, time t2 in FIG. 3 ).

[0076] 1 supplies a drive voltage V1 to the vibrator 1 so that the vibrator 1 vibrates intermittently, as shown in Fig. 3, but the drive voltage V1 may also be supplied to the vibrator 1 so that the vibrator 1 vibrates constantly. In this case, the period (reverberation period of the vibrator 1) T2 shown in Fig. 3 does not exist. In this case, the determination unit 7 compares the amplitude value of the detection signal K1 with a threshold value Vt1 at predetermined intervals during the vibration period of the vibrator 1, and determines whether or not there is contact with the object from outside based on the comparison result of the amplitude value of the detection signal K1 with the threshold value Vt1.

[0077] On the other hand, in the touch determination system A1 of the first embodiment, the oscillator circuit 10 supplies the drive voltage V1 to the vibrator 1 so that the vibrator 1 vibrates intermittently, and the determination unit 7 determines whether or not the object has been touched from the outside based on the comparison result between the amplitude value of the detection signal K1 and the threshold value Vt1 during the stable period T3 of the vibrator 1. As a result, the touch determination system A1 of the first embodiment can achieve lower power consumption than when the vibrator 10 is constantly vibrating.

[0078] The touch determination system A1 includes a temperature sensor 9 in the first embodiment, but may not include the temperature sensor 9. The touch detection mechanism B1 includes a pair of fixing portions 50 in the first embodiment, but may not include the pair of fixing portions 50. Furthermore, the touch detection mechanism B1 includes a pair of groove portions 60 in the first embodiment, but may not include the pair of groove portions 60.

[0079] The material of the frame 40 is not limited to metal and may be, for example, glass. Alternatively, the material of the frame 40 may be a resin containing a mixture of metal and glass. The resin containing a mixture of metal and glass has high rigidity, and examples of such resins include super engineering plastics.

[0080] Although the vibrator 1 has a feedback electrode 38 in the first embodiment, it may not have the feedback electrode 38. The vibrator 1 is not limited to a piezoelectric element, and may be, for example, a small vibrator that generates vibrations (e.g., an electromagnet, a magnetostrictive element, a quartz vibrator, etc.). The number of vibrators 1 is not limited to one, and may be multiple. The detection unit 2 is located outside the control device 3, but may also be located inside the control device 3.

[0081] The electronic device C1 is not limited to a mobile device, and may be, for example, an operation panel of a vehicle. That is, the touch determination system A1 may be used in, for example, an electronic device C1 such as an operation panel of a vehicle. The electronic device C1 has two touch detection mechanisms B1, but may have three or more touch detection mechanisms B1, or may have one touch detection mechanism B1. That is, the number of touch detection mechanisms B1 may be multiple or one. The control device 3 may be, for example, a control device for the electronic device C1.

[0082] 6, a touch determination system A2 according to the second embodiment differs from the touch determination system A1 according to the first embodiment in that the configuration of the amplitude detection unit 19 of the detection unit 2 is different. Note that, in the touch determination system A2 according to the second embodiment, the same components as those in the touch determination system A1 according to the first embodiment (see FIGS. 1 to 5) are denoted by the same reference numerals and description thereof will be omitted.

[0083] A touch determination system A2 according to the second embodiment will be described below with reference to FIG.

[0084] The amplitude detection unit 19 of the touch determination system A2 has, for example, a downconverter 35, a signal generation unit 30, and a digital signal processing unit 27. The control unit 6 is electrically connected to the signal generation unit 30. The control unit 6 controls, for example, the downconverter 35, the signal generation unit 30, and the digital signal processing unit 27.

[0085] The signal generating unit 30 generates a local signal S6 and outputs it to the 90-degree divider 29. The local signal S6 is a signal for down-converting the frequency of the vibration signal S1. The signal generating unit 30 has a frequency divider 31 and a multiplier 32.

[0086] The frequency divider 31 divides the frequency (second frequency) of the multiplied signal S3 from the VCO 16 of the PLL multiplier circuit 5. Specifically, the frequency divider 31 converts the second frequency of the multiplied signal S3 to a frequency (fifth frequency) that is 1 / N times the frequency of the multiplied signal S3 and outputs a signal including the fifth frequency to the multiplier 32. In other words, the fifth frequency is a frequency lower than the second frequency. For example, the frequency divider 31 converts the second frequency of the multiplied signal S3 to a frequency (fifth frequency) that is 1 / 300 times the frequency of the multiplied signal S3. The fifth frequency is, for example, 1 kHz. The frequency divider 31 is electrically connected to the VCO 16. The frequency divider 31 is also electrically connected to the 90-degree divider 29 via the multiplier 32. The frequency division value (1 / N value) of the frequency divider 31 is, for example, preset by the control unit 6. The division value in the frequency divider 31 is set so that the fourth frequency of the down-converted signal S4 is within the range of 1 kHz ±5%.

[0087] The multiplier 32 multiplies the fifth frequency included in the signal from the frequency divider 31. Specifically, the multiplier 32 converts the fifth frequency of the signal from the frequency divider 31 into a frequency (sixth frequency) that is M times (M≧2) the fifth frequency, and outputs a signal (local signal) S6 including the sixth frequency to the 90-degree divider 29. In other words, the sixth frequency is a frequency higher than the fifth frequency. For example, the multiplier 32 converts the fifth frequency of the signal from the frequency divider 31 into a frequency (sixth frequency) that is 31 times the fifth frequency. The sixth frequency is, for example, 31 kHz. The multiplication value (M value) of the multiplier 32 is set in advance by, for example, the control unit 6. The multiplication value of the multiplier 32 is set so that the fourth frequency of the down-converted signal S4 is within a range of 1 kHz±5%.

[0088] Based on the local signal S6 from the signal generating unit 30, the 90-degree divider 29 generates a signal (third signal) that is the local signal S6 as is and a signal (fourth signal) that is the local signal S6 with its phase shifted by 90 degrees. The 90-degree divider 29 outputs the third signal to the first mixer 24a and the fourth signal to the second mixer 24b, for example. The operation of the first mixer 24a is the same as when the first signal is input from the 90-degree divider 29, except that the signal input from the 90-degree divider 29 is different, and therefore a description thereof will be omitted. The operation of the second mixer 24b is the same as when the second signal is input from the 90-degree divider 29, except that the signal input from the 90-degree divider 29 is different, and therefore a description thereof will be omitted.

[0089] The downconverter 35 of the touch determination system A2 downconverts the frequency of the vibration signal S1 in accordance with a signal (local signal) S6 obtained by multiplying and dividing the signal (multiplied signal S3 in the example of FIG. 6 ) from the PLL multiplication circuit 5. As a result, the touch determination system A2 can determine whether or not the object has been touched from the outside, as well as the degree of pressure P1 on the object due to the external contact, similar to the touch determination system A1 of the first embodiment.

[0090] Furthermore, the touch determination system A2 does not include the local oscillator 28 (see FIG. 1 ) of the first embodiment, but includes a signal generating unit 30 that generates a local signal S6 in response to a signal from the PLL multiplication circuit 5. As a result, the touch determination system A2 can input the local signal S6 to the 90-degree divider 29 of the downconverter 35 without going through the control unit 6, and can therefore respond more quickly to changes in the frequency of the vibration signal S1 than the touch determination system A1 of the first embodiment. In other words, the touch determination system A2 can determine the degree of pressure P1 on the object due to external contact more quickly than the touch determination system A1 of the first embodiment.

[0091] Here, when the determination unit 7 determines that there is no external contact with the object, the control unit 6 preferably controls the detection unit 2 to stop operation of the frequency counter 4. Also, when the determination unit 7 determines that there is external contact with the object, the control unit 6 preferably controls the detection unit 2 to operate the frequency counter 4. As a result, in the touch determination system A2, when there is no external contact with the object, the operation of the frequency counter 4 stops, thereby making it possible to reduce power consumption compared to when the frequency counter 4 operates.

[0092] As a modification of the second embodiment, modifications similar to those of the touch determination system A1 according to the modification of the first embodiment are possible. Therefore, the touch determination system A2 according to the modification of the second embodiment also achieves the same effects as those of the touch determination system A2 according to the second embodiment.

[0093] 7, a touch determination system A3 according to the third embodiment differs from the touch determination system A2 according to the second embodiment in that the detection unit 2 is connected differently. Note that, in the touch determination system A3 according to the third embodiment, the same components as those in the touch determination system A2 according to the second embodiment (see FIG. 6) are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0094] A touch determination system A3 according to the third embodiment will be described below with reference to FIG.

[0095] The frequency divider 31 of the signal generating unit 30 divides the frequency of the frequency-divided signal S5 from the frequency divider 17 of the PLL multiplier circuit 5. Specifically, the frequency divider 31 converts the third frequency of the frequency-divided signal S5 to a frequency that is 1 / N times the frequency (the fifth frequency) and outputs a signal including the fifth frequency to the multiplier 32. In other words, the fifth frequency is a frequency lower than the third frequency. For example, the frequency divider 31 converts the third frequency of the frequency-divided signal S5 to a frequency that is 1 / 30 times the frequency (the fifth frequency). The frequency divider 31 is electrically connected to the frequency divider 17 (more specifically, to the output terminal of the frequency divider 17).

[0096] The downconverter 35 of the touch determination system A3 downconverts the frequency of the vibration signal S1 in accordance with a signal (local signal) S6 obtained by multiplying and dividing the signal (frequency-divided signal S5 in the example of FIG. 7 ) from the PLL multiplication circuit 5. As a result, the touch determination system A3 can determine whether or not the object has been touched from the outside, as well as the degree of pressure P1 on the object due to the external contact, similar to the touch determination system A2 of the second embodiment.

[0097] Furthermore, the touch determination system A3 does not include the local oscillator 28 (see FIG. 1 ) of the first embodiment, but includes a signal generating unit 30 that generates a local signal S6 in response to a signal from the PLL multiplication circuit 5. As a result, the touch determination system A3 can input the local signal S6 to the 90-degree divider 29 of the downconverter 35 without going through the control unit 6, and can therefore respond more quickly to changes in the frequency of the vibration signal S1 than the touch determination system A1 of the first embodiment. In other words, the touch determination system A3 can determine the degree of pressure P1 on the object due to external contact more quickly than the touch determination system A1 of the first embodiment.

[0098] As a modification of the third embodiment, modifications similar to those of the touch determination system A2 according to the modification of the second embodiment are possible. Therefore, the touch determination system A3 according to the modification of the third embodiment also achieves the same effects as those of the touch determination system A3 according to the third embodiment.

[0099] 8, a touch determination system A4 according to embodiment 4 differs from the touch determination system A2 according to embodiment 2 in that the detection unit 2 is connected differently. Note that, in the touch determination system A4 according to embodiment 4, components similar to those in the touch determination system A2 according to embodiment 2 (see FIG. 6) are denoted by the same reference numerals and descriptions thereof will be omitted.

[0100] A touch determination system A4 according to the fourth embodiment will be described below with reference to FIG.

[0101] The frequency divider 31 of the signal generating unit 30 divides the frequency of the pulse signal S2 from the waveform shaper 12 of the PLL multiplier circuit 5. Specifically, the frequency divider 31 converts the first frequency of the pulse signal S2 to a frequency that is 1 / N times the frequency (the fifth frequency) and outputs a signal including the fifth frequency to the multiplier 32. In other words, the fifth frequency is a frequency lower than the first frequency. For example, the frequency divider 31 converts the first frequency of the pulse signal S2 to a frequency that is 1 / 30 times the frequency (the fifth frequency). The frequency divider 31 is electrically connected to the waveform shaper 12 (more specifically, to the output terminal of the waveform shaper 12).

[0102] The downconverter 35 of the touch determination system A4 downconverts the frequency of the vibration signal S1 in accordance with a signal (local signal) S6 obtained by multiplying and dividing the signal (pulse signal S2 in the example of FIG. 8 ) from the PLL multiplication circuit 5. As a result, the touch determination system A4 can determine whether or not the object has been touched from the outside, and can also determine the degree of pressure P1 on the object due to the external contact, similar to the touch determination system A2 of the second embodiment.

[0103] Furthermore, the touch determination system A4 does not include the local oscillator 28 (see FIG. 1 ) of the first embodiment, but includes a signal generating unit 30 that generates a local signal S6 in response to a signal from the PLL multiplication circuit 5. As a result, the touch determination system A4 can input the local signal S6 to the 90-degree divider 29 of the downconverter 35 without going through the control unit 6, and can therefore respond more quickly to changes in the frequency of the vibration signal S1 than the touch determination system A1 of the first embodiment. In other words, the touch determination system A4 can determine the degree of pressure P1 on the object due to external contact more quickly than the touch determination system A1 of the first embodiment.

[0104] As a modification of the fourth embodiment, modifications similar to those of the touch determination system A2 according to the modification of the second embodiment are possible. Therefore, the touch determination system A4 according to the modification of the fourth embodiment also achieves the same effects as those of the touch determination system A4 according to the fourth embodiment.

[0105] 9, a touch determination system A5 according to the fifth embodiment differs from the touch determination system A2 according to the second embodiment in that the signal generation unit 36 ​​has a different configuration. Note that, in the touch determination system A5 according to the fifth embodiment, components similar to those in the touch determination system A2 according to the second embodiment (see FIG. 6) are denoted by the same reference numerals and descriptions thereof will be omitted.

[0106] A touch determination system A5 according to the fifth embodiment will be described below with reference to FIG.

[0107] The signal generating unit 36 ​​of the touch determination system A5 generates a local signal S8 and outputs it to the 90-degree divider 29. The local signal S8 is a signal for down-converting the frequency of the vibration signal S1. The signal generating unit 36 ​​includes a frequency divider 31 and a mixer 33. The control unit 6 is electrically connected to the signal generating unit 36. The control unit 6 controls, for example, the down-converter 35, the signal generating unit 36, and the digital signal processing unit 27.

[0108] The mixer 33 outputs a composite signal of the signal S7 from the frequency divider 31 (a signal including the fifth frequency) and the pulse signal S2 from the waveform shaper 12 as a local signal S8 to the 90-degree divider 29. The fifth frequency of the signal S7 from the frequency divider 31 is, for example, 1 kHz. The first frequency of the pulse signal S2 is, for example, 30 kHz. The frequency (seventh frequency) of the local signal S8 is, for example, 31 kHz. A first input terminal of the mixer 33 is electrically connected to the frequency divider 31 (more specifically, the output terminal of the frequency divider 31). A second input terminal of the mixer 33 is electrically connected to the waveform shaper 12 (more specifically, the output terminal of the waveform shaper 12). An output terminal of the mixer 33 is electrically connected to the 90-degree divider 29.

[0109] Based on the local signal S8 from the signal generating unit 36, the 90-degree divider 29 generates a signal (fifth signal) that is the local signal S8 as is and a signal (sixth signal) that is the local signal S8 with its phase shifted by 90°. The 90-degree divider 29 outputs the fifth signal to the first mixer 24a and the sixth signal to the second mixer 24b, for example. The operation of the first mixer 24a is the same as when the third signal is input from the 90-degree divider 29, except that the signal input from the 90-degree divider 29 is different, and therefore a description thereof will be omitted. The operation of the second mixer 24b is the same as when the fourth signal is input from the 90-degree divider 29, except that the signal input from the 90-degree divider 29 is different, and therefore a description thereof will be omitted.

[0110] The downconverter 35 of the touch determination system A5 downconverts the frequency of the vibration signal S1 in response to a local signal S8 that is a composite signal of the pulse signal S2 from the waveform shaper 12 and the signal S7 from the frequency divider 31. That is, the downconverter 35 downconverts the frequency of the vibration signal S1 in response to a composite signal (local signal S8) of the signal (pulse signal) S2 that includes the frequency (first frequency) before being multiplied by the PLL multiplier circuit 5 and the signal S7 that is obtained by dividing the frequency (second frequency) after being multiplied by the PLL multiplier circuit 5 (signal including the fifth frequency). As a result, the touch determination system A5, like the touch determination system A2 of the second embodiment, can determine whether or not the object has been touched from the outside, and can also determine the degree of pressure P1 on the object due to the external contact.

[0111] Furthermore, the touch determination system A5 does not include the local oscillator 28 (see FIG. 1 ) of the first embodiment, but includes a signal generation unit 36 ​​that generates a local signal S8 in response to a signal from the PLL multiplication circuit 5. As a result, the touch determination system A5 can input the local signal S8 to the 90-degree divider 29 of the downconverter 35 without going through the control unit 6, and can therefore respond more quickly to changes in the frequency of the vibration signal S1 than the touch determination system A1 of the first embodiment. In other words, the touch determination system A5 can determine the degree of pressure P1 on the object due to external contact more quickly than the touch determination system A1 of the first embodiment.

[0112] As a modification of the fifth embodiment, modifications similar to those of the touch determination system A2 according to the modification of the second embodiment are possible. Therefore, the touch determination system A5 according to the modification of the fifth embodiment also achieves the same effects as those of the touch determination system A5 according to the fifth embodiment.

[0113] 10 , a touch determination system A6 according to the sixth embodiment differs from the touch determination system A5 according to the fifth embodiment in that the configuration of the amplitude detection unit 19 of the detection unit 2 is different. Note that, in the touch determination system A6 according to the sixth embodiment, the same components as those in the touch determination system A5 according to the fifth embodiment (see FIG. 9 ) are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0114] A touch determination system A6 according to the sixth embodiment will be described below with reference to FIG.

[0115] The amplitude detection unit 19 of the touch determination system A6 has, for example, a downconverter 35, a fractional frequency divider 34, and a digital signal processing unit 27. The control unit 6 is electrically connected to the fractional frequency divider 34. The control unit 6 controls, for example, the downconverter 35, the fractional frequency divider 34, and the digital signal processing unit 27.

[0116] The fractional frequency divider 34 fractionally divides the second frequency of the multiplied signal S3 from the VCO 16 of the PLL multiplier circuit 5. Specifically, the fractional frequency divider 34 converts the second frequency of the multiplied signal S3 to a frequency 1 / Q times higher (the eighth frequency) and outputs a signal including the eighth frequency as the local signal S9 to the 90-degree divider 29. In other words, the eighth frequency is lower than the second frequency. For example, the fractional frequency divider 34 converts the second frequency of the multiplied signal S3 to a frequency 1 / 9.7 times higher (the eighth frequency). The eighth frequency is, for example, 30.92 kHz. The fractional frequency divider 34 is electrically connected to the VCO 16. The fractional frequency divider 34 is also electrically connected to the 90-degree divider 29. The fractional frequency division value (the 1 / Q value) of the fractional frequency divider 34 is preset, for example, by the control unit 6. The fractional frequency division value in the fractional frequency divider 34 is set so that the fourth frequency of the down-converted signal S4 is within the range of 1 kHz ±5%.

[0117] Based on the local signal S9 from the fractional divider 34, the 90-degree divider 29 generates a signal (seventh signal) that is the local signal S9 as is and a signal (eighth signal) that is the local signal S9 with its phase shifted by 90°. The 90-degree divider 29 outputs the seventh signal to the first mixer 24a and the eighth signal to the second mixer 24b, for example. The operation of the first mixer 24a is the same as when the fifth signal is input from the 90-degree divider 29, except that the signal input from the 90-degree divider 29 is different, and therefore a description thereof will be omitted. The operation of the second mixer 24b is the same as when the sixth signal is input from the 90-degree divider 29, except that the signal input from the 90-degree divider 29 is different, and therefore a description thereof will be omitted.

[0118] The downconverter 35 of the touch determination system A6 downconverts the frequency of the vibration signal S1 in response to the local signal S9 from the fractional frequency divider 34. That is, the downconverter 35 downconverts the frequency of the vibration signal S1 in response to a signal (local signal) S9 obtained by fractionally frequency-dividing a signal (multiplied signal) S3 including a frequency (second frequency) multiplied by the PLL multiplication circuit 5. In this way, the touch determination system A6 can determine whether or not the object has been touched from the outside, and can also determine the degree of pressure P1 on the object due to the external contact, similar to the touch determination system A5 of the fifth embodiment.

[0119] Furthermore, the touch determination system A6 does not include the local oscillator 28 (see FIG. 1 ) of the first embodiment, but includes a fractional frequency divider 34 that outputs a local signal S9 to a 90-degree divider 29 in response to a signal from the PLL multiplication circuit 5. This allows the touch determination system A6 to input the local signal S9 to the 90-degree divider 29 of the downconverter 35 without going through the control unit 6, and therefore can respond to changes in the frequency of the vibration signal S1 more quickly than the touch determination system A1 of the first embodiment. In other words, the touch determination system A6 can determine the degree of pressure P1 on the object due to external contact more quickly than the touch determination system A1 of the first embodiment.

[0120] Furthermore, the touch determination system A6 does not include the signal generation unit 36 ​​(divider 31 and mixer 33) of embodiment 5, but includes the fractional frequency divider 34, so that it is only necessary to fractionally divide the frequency of the signal from the PLL multiplication circuit 5, and the local signal S9 can be input to the 90-degree divider 29 of the downconverter 35 earlier than the touch determination system A5 of embodiment 5. Therefore, the touch determination system A6 can determine the degree of pressure P1 on the object due to external contact earlier than the touch determination system A5 of embodiment 5. In other words, the touch determination system A6 can determine the degree of pressure P1 on the object due to external contact even earlier than the touch determination system A1 of embodiment 1.

[0121] As a modification of the sixth embodiment, modifications similar to those of the touch determination system A5 according to the modification of the fifth embodiment are possible. Therefore, the touch determination system A6 according to the modification of the sixth embodiment also achieves the same effects as those of the touch determination system A6 according to the sixth embodiment.

[0122] The above-described first to sixth embodiments and modifications are merely a part of the various embodiments and modifications of the present disclosure.

[0123] The present disclosure is not limited to the above-described embodiments, and at least some of the configurations of the embodiments and modified examples can be combined as appropriate and applied.

[0124] Furthermore, the touch determination systems A1 to A6 according to the first to sixth embodiments do not necessarily need to be integrated into one housing. For example, the components of the touch determination systems A1 to A6 may be distributed among multiple housings.

[0125] (Aspects) The present specification discloses the following aspects.

[0126] A touch determination system (A1 to A6) according to a first aspect includes a self-excited vibrator (1), a detection unit (2), and a determination unit (7). The detection unit (2) detects a vibration signal (S1) corresponding to the vibration of the vibrator (1). The determination unit (7) determines whether or not an object (90) is being contacted from the outside (100) based on a change in the amplitude of the vibration signal (S1) detected by the detection unit (2). The determination unit (7) further determines the degree of pressure (P1) on the object (90) due to contact from the outside (100) based on a change in the frequency of the vibration signal (S1) detected by the detection unit (2).

[0127] According to this aspect, it is possible to determine whether or not the object (90) is being contacted from the outside (100), and to determine the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0128] In the touch determination systems (A1 to A6) according to the second aspect, in the first aspect, the detection unit (2) has a frequency counter (4) that measures the frequency of the vibration signal (S1), and the determination unit (7) determines the degree of pressure (P1) based on a change in the frequency measured by the frequency counter (4).

[0129] According to this aspect, the configuration of the detection unit (2) can be simplified.

[0130] In the touch determination systems (A1 to A6) according to the third aspect, in the second aspect, the detection unit (2) further includes a PLL multiplication circuit (5) that multiplies the frequency of the vibration signal (S1). The frequency counter (4) measures the frequency multiplied by the PLL multiplication circuit (5).

[0131] According to this aspect, the frequency of the vibration signal (S1) can be detected at high speed.

[0132] A touch determination system (A2; A3; A4) according to a fourth aspect is the third aspect, wherein the detection unit (2) further includes a downconverter (35) that downconverts the frequency of the vibration signal (S1). The downconverter (35) downconverts the frequency of the vibration signal (S1) in response to a signal (S6) obtained by multiplying and dividing a signal (S3; S5; S2) from the PLL multiplication circuit (5). The determination unit (7) determines whether or not there is contact from the outside (100) to the object (90) based on a change in amplitude of a signal (S4) that includes the frequency downconverted by the downconverter (35).

[0133] According to this aspect, it is possible to determine whether or not the object (90) is being contacted from the outside (100), and to determine the degree of pressure (P1) on the object (90) due to contact from the outside (100). Also, according to this aspect, it is possible to quickly determine the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0134] A touch determination system (A5) according to a fifth aspect is the third aspect, wherein the detection unit (2) further includes a downconverter (35) that downconverts the frequency of the vibration signal (S1). The downconverter (35) downconverts the frequency of the vibration signal (S1) in response to a composite signal (S8) of a signal (S2) including a frequency before being multiplied by the PLL multiplier circuit (5) and a signal (S7) obtained by dividing the frequency after being multiplied by the PLL multiplier circuit (5). The determination unit (7) determines whether or not an object (90) has been touched from the outside (100) based on a change in amplitude of the signal (S4) including the frequency downconverted by the downconverter (35).

[0135] According to this aspect, it is possible to determine whether or not the object (90) is being contacted from the outside (100), and to determine the degree of pressure (P1) on the object (90) due to contact from the outside (100). Also, according to this aspect, it is possible to quickly determine the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0136] A touch determination system (A6) according to a sixth aspect is the third aspect, wherein the detection unit (2) further includes a downconverter (35) that downconverts the frequency of the vibration signal (S1). The downconverter (35) downconverts the frequency of the vibration signal (S1) in response to a signal (S9) that is a fractional frequency division of the frequency multiplied by the PLL multiplication circuit (5). The determination unit (7) determines whether or not there is contact from the outside (100) to the object (90) based on a change in amplitude of a signal (S4) that includes the frequency downconverted by the downconverter (35).

[0137] According to this aspect, it is possible to determine whether or not the object (90) is being contacted from the outside (100), and to determine the degree of pressure (P1) on the object (90) due to contact from the outside (100). Also, according to this aspect, it is possible to quickly determine the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0138] A touch determination system (A2 to A6) according to a seventh aspect is any one of the second to sixth aspects, further comprising a control unit (6) that controls the detection unit (2). The control unit (6) controls the detection unit (2) so that the operation of the frequency counter (4) stops when the determination unit (7) determines that there is no contact from the outside (100) with the object (90). The control unit (6) controls the detection unit (2) so that the frequency counter (4) operates when the determination unit (7) determines that there is contact from the outside (100) with the object (90).

[0139] According to this aspect, it is possible to reduce power consumption.

[0140] A touch determination system (A1) according to an eighth aspect is the third aspect, wherein the detection unit (2) further includes a downconverter (35) and a local oscillator (28). The downconverter (35) downconverts the frequency of the vibration signal (S1). The local oscillator (28) outputs a local signal (S11) for downconverting the frequency of the vibration signal (S1). The local oscillator (28) outputs the local signal (S11) based on a frequency measured by a frequency counter (4). The downconverter (35) downconverts the frequency of the vibration signal (S1) in accordance with the local signal (S11) from the local oscillator (28). The determination unit (7) determines whether or not there is contact from the outside (100) to an object (90) based on a change in amplitude of a signal (S4) including the frequency downconverted by the downconverter (35).

[0141] According to this aspect, it is possible to stabilize the frequency down-converted by the down-converter (35). Also, according to this aspect, it is possible to improve the accuracy of determining whether or not the object (90) is in contact with the outside (100).

[0142] The touch determination system (A1) according to a ninth aspect is the eighth aspect, and further includes a control unit (6) that controls the detection unit (2). When the determination unit (7) determines that there is no contact from the outside (100) to the object (90), the control unit (6) controls the detection unit (2) so that the frequency counter (4) and the PLL multiplication circuit (5) stop operating. When the determination unit (7) determines that there is contact from the outside (100) to the object (90), the control unit (6) controls the detection unit (2) so that the frequency counter (4) and the PLL multiplication circuit (5) operate.

[0143] According to this aspect, it is possible to reduce power consumption.

[0144] The touch determination system (A1) according to a tenth aspect is the seventh or ninth aspect, further comprising a temperature sensor (9) that detects an ambient temperature of the vibrator (1). The control unit (6) corrects the amplitude and frequency of the vibration signal (S1) based on the ambient temperature detected by the temperature sensor (9).

[0145] According to this aspect, the influence of the ambient temperature of the vibrator (1) is reduced, and it is possible to determine whether or not there is contact from the outside (100) to the object (90), as well as to determine the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0146] A touch determination system (A1 to A6) according to an eleventh aspect is any one of the first to tenth aspects, further comprising a frame (40) through which vibrations of the vibrator (1) are propagated. The frame (40) includes an attachment section (41), a pressure receiving section (42), and a propagation section (43). The vibrator (1) is attached to the attachment section (41), and the frame (40) vibrates in response to vibrations of the vibrator (1). The pressure receiving section (42) receives pressure (P1) due to contact from the outside (100). The propagation section (43) transmits the vibrations of the attachment section (41) to the pressure receiving section (42), and transmits stress corresponding to the pressure (P1) received by the pressure receiving section (42) to the attachment section (41). The vibration frequency of the attachment section (41) changes in response to the stress.

[0147] According to this aspect, it is possible to determine whether or not the object (90) is being contacted from the outside (100), and to determine the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0148] A touch determination system (A1 to A6) according to a twelfth aspect is the eleventh aspect, wherein the frame (40) further includes a support portion (44). The support portion (44) connects the mounting portion (41) and the pressure receiving portion (42) and supports the propagation portion (43). The propagation portion (43) is columnar. A first end (8a) of the propagation portion (43) is coupled to the support portion (44). A second end (8b) of the propagation portion (43) is coupled to the pressure receiving portion (42). The bending rigidity of the support portion (44) is higher than the bending rigidity of the mounting portion (41). The vibration frequency of the mounting portion (41) changes depending on the stress applied to the support portion (44) via the propagation portion (43).

[0149] According to this aspect, it is possible to improve the accuracy of determining the degree of pressure (P1) on the object (90) due to contact from the outside (100).

[0150] REFERENCE SIGNS LIST 1 vibrator 2 detection unit 4 frequency counter 5 PLL multiplication circuit 6 control unit 7 determination unit 8a first end 8b second end 9 temperature sensor 28 local oscillator 35 downconverter 40 frame 41 mounting unit 42 pressure receiving unit 43 propagation unit 44 support unit 90 housing (object) 100 person (outside) A1 to A6 touch determination system P1 pressure S1 vibration signal S2 pulse signal (signal from PLL multiplication circuit) S3 multiplied signal (signal from PLL multiplication circuit) S4 downconverted signal (signal including downconverted frequency) S5 frequency-divided signal (signal from PLL multiplication circuit) S6 local signal (signal obtained by multiplying and dividing the signal from the PLL multiplication circuit) S7 S8: local signal (synthesized signal) S9: local signal (fractionally divided signal after being multiplied by the PLL multiplier circuit) S11: local signal

Claims

1. A touch determination system comprising: a self-excited vibrator; a detection unit that detects a vibration signal corresponding to vibration of the vibrator; and a determination unit that determines whether or not an object has been contacted from the outside based on a change in the amplitude of the vibration signal detected by the detection unit, wherein the determination unit further determines the degree of pressure on the object due to the external contact based on a change in the frequency of the vibration signal detected by the detection unit.

2. The touch determination system according to claim 1, wherein the detection unit has a frequency counter that measures the frequency of the vibration signal, and the determination unit determines the degree of pressure based on a change in the frequency measured by the frequency counter.

3. The touch determination system according to claim 2, wherein the detection unit further has a PLL multiplication circuit that multiplies the frequency of the vibration signal, and the frequency counter measures the frequency multiplied by the PLL multiplication circuit.

4. The touch determination system according to claim 3, wherein the detection unit further has a downconverter that downconverts the frequency of the vibration signal, the downconverter downconverting the frequency of the vibration signal in accordance with a signal obtained by multiplying and dividing the signal from the PLL multiplication circuit, and the determination unit determines whether or not there is contact from the outside to the object based on a change in amplitude of a signal including the frequency downconverted by the downconverter.

5. The touch determination system according to claim 3, wherein the detection unit further has a downconverter that downconverts the frequency of the vibration signal, and the downconverter downconverts the frequency of the vibration signal in response to a composite signal of a signal including a frequency before being multiplied by the PLL multiplier circuit and a signal obtained by dividing the frequency after being multiplied by the PLL multiplier circuit, and the determination unit determines whether or not there is contact from the outside to the object based on a change in amplitude of the signal including the frequency downconverted by the downconverter.

6. The touch determination system according to claim 3, wherein the detection unit further has a downconverter that downconverts the frequency of the vibration signal, and the downconverter downconverts the frequency of the vibration signal in accordance with a signal that is a fractional division of the frequency that has been multiplied by the PLL multiplication circuit, and the determination unit determines whether or not there is contact from the outside to the object based on a change in amplitude of a signal that includes the frequency that has been downconverted by the downconverter.

7. A touch determination system as described in any one of claims 2 to 6, further comprising a control unit that controls the detection unit, wherein the control unit controls the detection unit so that operation of the frequency counter stops when the determination unit determines that there is no contact from the outside to the object, and controls the detection unit so that the frequency counter operates when the determination unit determines that there is contact from the outside to the object.

8. The touch determination system according to claim 3, wherein the detection unit further comprises a downconverter that downconverts the frequency of the vibration signal, and a local oscillator that outputs a local signal for downconverting the frequency of the vibration signal, the local oscillator outputs the local signal based on the frequency measured by the frequency counter, the downconverter downconverts the frequency of the vibration signal in accordance with the local signal from the local oscillator, and the determination unit determines whether or not there is contact from the outside to the object based on a change in amplitude of a signal including the frequency downconverted by the downconverter.

9. The touch determination system according to claim 8, further comprising a control unit that controls the detection unit, wherein the control unit controls the detection unit so that the frequency counter and the PLL multiplication circuit stop operating when the determination unit determines that there is no contact from the outside to the target object, and controls the detection unit so that the frequency counter and the PLL multiplication circuit operate when the determination unit determines that there is contact from the outside to the target object.

10. A touch determination system according to claim 7 or claim 9, further comprising a temperature sensor that detects an ambient temperature of the vibrator, and wherein the control unit corrects the amplitude and frequency of the vibration signal based on the ambient temperature detected by the temperature sensor.

11. A touch determination system as described in any one of claims 1 to 10, further comprising a frame through which the vibrations of the vibrator are propagated, the frame including: a mounting section to which the vibrator is attached and which vibrates in response to the vibrations of the vibrator; a pressure receiving section which receives pressure due to the contact from the outside; and a propagation section which transmits the vibrations of the mounting section to the pressure receiving section and transmits stress corresponding to the pressure received by the pressure receiving section to the mounting section, and the vibration frequency of the mounting section changes in response to the stress.

12. The touch determination system of claim 11, wherein the frame body further includes a support portion that connects the mounting portion and the pressure receiving portion and supports the propagation portion, the propagation portion being columnar, a first end of the propagation portion being coupled to the support portion, a second end of the propagation portion being coupled to the pressure receiving portion, the bending rigidity of the support portion being higher than the bending rigidity of the mounting portion, and the vibration frequency of the mounting portion changing according to the stress applied to the support portion via the propagation portion.

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