NON-CONTACT SENSOR DEVICE AND NON-CONTACT SENSING METHOD

Abstract

To provide a non-contact sensor device capable of reducing the number of components and achieving reduction in cost.SOLUTION: Disclosed is a non-contact sensor device 10A which detects a position of an object in a non-contact state and includes: a vibration plate 11; ultrasonic vibrators 12a,12b for generating deflection vibration on the vibration plate 11; a driving part 13 for applying an AC voltage to the ultrasonic vibrators 12a, 12b; a phase information acquisition part 15 for acquiring the phase information on an alternating current flowing in the ultrasonic vibrators 12a, 12b; and a detection part 17 for detecting the position of the object relative to the vibration plate. The detection unit 17 detects the position of the object in the propagation direction of the deflection vibration based on the phase information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a non-contact sensor device and a non-contact sensing method. [Background technology]

[0002] Known examples of non-contact sensor devices and non-contact sensing methods include the method described in Patent Document 1 and the device described in Patent Document 2.

[0003] The non-contact sensing method described in Patent Document 1 includes the steps of providing a data selection unit, transmitting a signal in the vicinity of the data selection unit, changing the path of the transmitted signal through blocking by a selection device, detecting the changed signal, determining the position of the selection device from the changed signal, and correlating the position of the selection device with the data selection unit.

[0004] The input device, which is a non-contact sensor device described in Patent Document 2, has a display unit that displays a plurality of operation positions, and a detection unit that detects in a non-contact manner an operation at an operation position set in a specific space in front of the input device corresponding to each of the plurality of operation position displays. The detection unit has a first piezoelectric element that oscillates ultrasonic waves toward the space in front of the input device, a second piezoelectric element that detects the ultrasonic waves oscillated by the first piezoelectric element, and a determination unit that determines which operation position has been operated based on the detection result by the second piezoelectric element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2007-525669 [Patent Document 2] JP 2012-155526 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the non-contact sensing method described in Patent Document 1, since a large number of signal emitters for transmitting signals and signal receivers for receiving signals are required, for example, in the step of matching the position of the selection device with the data selection unit, the signal processing may become complicated. Thus, the non-contact sensing method described in Patent Document 1 has a problem that the number of parts increases, leading to an increase in costs.

[0007] In the non-contact sensor device described in Patent Document 2, the first piezoelectric element and the second piezoelectric element are essential components, and moreover, a large number of second piezoelectric elements are required. Therefore, in the determination unit that determines which operation position has been operated based on the detection result by the second piezoelectric element, the signal processing may become complicated. Thus, in the non-contact sensor device described in Patent Document 2, as in the non-contact sensing method described in Patent Document 1, there is a problem that the number of parts increases, leading to an increase in costs.

[0008] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a non-contact sensor device and a non-contact sensing method that can reduce the number of parts and lower costs. [Means for solving the problem]

[0009] In order to solve the above problems, a non-contact sensor device according to the present invention comprises: A non-contact sensor device that detects a position of an object in a non-contact manner, A diaphragm; an ultrasonic vibrator that generates a flexural vibration in the vibration plate; A drive unit that applies an AC voltage to the ultrasonic transducer; a phase information acquisition unit that acquires phase information of an alternating current flowing through the ultrasonic transducer; A detection unit that detects a position of the object relative to the vibration plate; Equipped with The detection unit detects a position of the object in a propagation direction of the flexural vibration based on the phase information.

[0010] The non-contact sensor device includes: A current value information acquisition unit that acquires current value information of the AC current, It is preferable that the detection section detects a position of the object in a vibration direction of the flexural vibration based on the current value information.

[0011] In the non-contact sensor device, The ultrasonic transducer is A first ultrasonic transducer disposed on one side of the vibration plate in the propagation direction; A second ultrasonic transducer disposed on the other side of the vibration plate in the propagation direction; Including, The phase information acquisition unit can be configured to acquire, as the phase information, information relating to a phase difference between a first AC current flowing through the first ultrasonic transducer and a second AC current flowing through the second ultrasonic transducer.

[0012] In the non-contact sensor device, The ultrasonic transducer comprises a single third ultrasonic transducer, The diaphragm has a mechanical stiffness that changes in the propagation direction, The phase information acquisition unit can be configured to acquire, as the phase information, information relating to the phase of a third AC current flowing through the third ultrasonic transducer.

[0013] In the non-contact sensor device, The diaphragm may be configured such that its thickness varies in the direction of propagation.

[0014] In order to solve the above problems, a non-contact sensing method according to the present invention includes: A non-contact sensing method for detecting a position of an object in a non-contact manner, comprising: a driving step of applying an AC voltage to an ultrasonic vibrator provided on a vibration plate to generate a bending vibration in the vibration plate by ultrasonic vibration of the ultrasonic vibrator; An information acquisition step of acquiring phase information of an alternating current flowing through the ultrasonic transducer; a sensing step of sensing a position of the object relative to the diaphragm; Including, The detecting step detects a position of the object in a propagation direction of the flexural vibration based on the phase information.

[0015] The non-contact sensing method includes: In the information acquisition step, current value information of the AC current is acquired, In the detecting step, it is preferable to detect a position of the object in a vibration direction of the flexural vibration based on the current value information.

[0016] In the non-contact sensing method, The ultrasonic transducer is A first ultrasonic transducer disposed on one side of the vibration plate in the propagation direction; A second ultrasonic transducer disposed on the other side of the vibration plate in the propagation direction; Including, The information acquiring step can be configured to acquire, as the phase information, information relating to a phase difference between a first AC current flowing through the first ultrasonic transducer and a second AC current flowing through the second ultrasonic transducer.

[0017] In the non-contact sensing method, The ultrasonic transducer comprises a single third ultrasonic transducer, The diaphragm has a mechanical stiffness that changes in the propagation direction, The information acquiring step can be configured to acquire information about the phase of a third AC current flowing through the third ultrasonic transducer as the phase information.

[0018] In the non-contact sensing method, The diaphragm may be configured such that its thickness varies in the direction of propagation. Effect of the Invention

[0019] According to the present invention, it is possible to provide a non-contact sensor device and a non-contact sensing method that can reduce the number of parts and lower costs. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram of a non-contact sensor device according to a first embodiment. [Diagram 2] 2A to 2C are diagrams illustrating a vibration plate, a first ultrasonic transducer, and a second ultrasonic transducer according to the first embodiment. [Diagram 3] 1A is a diagram showing the positional relationship with the vibration plate when an object is moved in the y direction, and FIG. 1B is a diagram showing the change in phase difference between the current flowing through the first ultrasonic transducer and the current flowing through the second ultrasonic transducer when the object is moved in the y direction. [Figure 4] 1A is a diagram showing the positional relationship with the vibration plate when an object is moved in the z direction, and FIG. 1B is a diagram showing the change in the total current value of the current flowing through the first ultrasonic transducer and the current flowing through the second ultrasonic transducer when the object is moved in the z direction. [Diagram 5] FIG. 13 is a diagram showing changes in the phase difference between the current flowing through the first ultrasonic transducer and the current flowing through the second ultrasonic transducer when an object is moved in the y direction at each position in the z direction. [Figure 6] FIG. 11 is a block diagram of a non-contact sensor device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a non-contact sensor device and a non-contact sensing method according to the present invention will be described with reference to the accompanying drawings.

[0022] [First embodiment] (Non-contact sensor device) 1 shows a non-contact sensor device 10A according to a first embodiment of the present invention. The non-contact sensor device 10A includes a diaphragm 11, a first ultrasonic transducer 12a, a second ultrasonic transducer 12b, a driving unit 13, an information acquiring unit 14 (a phase information acquiring unit 15 and a current value information acquiring unit 16), and a detection unit 17.

[0023] The vibration plate 11 is configured to generate a flexural vibration by the ultrasonic vibration of the first ultrasonic transducer 12a and the second ultrasonic transducer 12b. In this embodiment, a metal plate having a length of 200 mm in the y direction (propagation direction of the flexural vibration) and a uniform thickness in the z direction (vibration direction of the flexural vibration) is used as the vibration plate 11.

[0024] The first ultrasonic transducer 12a is configured to generate ultrasonic vibrations when an AC voltage is applied, and to generate flexural vibrations in the vibration plate 11. The first ultrasonic transducer 12a is provided on one side of the vibration plate 11 in the y direction at the bottom. In this embodiment, a Langevin type transducer is used as the first ultrasonic transducer 12a. Note that the "AC" in the present invention includes not only sine waves but also rectangular waves, triangular waves, and the like.

[0025] The second ultrasonic transducer 12b is configured to generate ultrasonic vibrations when an AC voltage is applied, and to generate flexural vibrations in the vibration plate 11. The second ultrasonic transducer 12b is provided on the other side of the vibration plate 11 in the y direction at the lower part. In this embodiment, a Langevin type transducer similar to the first ultrasonic transducer 12a is used as the second ultrasonic transducer 12b.

[0026] The driving unit 13 is configured to apply an AC voltage to the first ultrasonic transducer 12a and the second ultrasonic transducer 12b. In this embodiment, the driving unit 13 applies an AC voltage of the same frequency and phase to the first ultrasonic transducer 12a and the second ultrasonic transducer 12b so that the first ultrasonic transducer 12a and the vibration plate 11 resonate with each other and the second ultrasonic transducer 12b and the vibration plate 11 resonate with each other. The driving unit 13 includes, for example, a function generator and an amplifier that amplifies the output (AC voltage signal) of the function generator.

[0027] The information acquiring unit 14 includes a current sensor (not shown) and is configured to acquire information on the first AC current flowing through the first ultrasonic transducer 12a during ultrasonic vibration and information on the second AC current flowing through the second ultrasonic transducer 12b during ultrasonic vibration. In this embodiment, the information acquiring unit 14 includes a phase information acquiring unit 15 and a current value information acquiring unit 16.

[0028] The phase information acquiring unit 15 acquires phase information of the first AC current and the second AC current. Specifically, the phase information acquiring unit 15 acquires phase information on each phase of the first AC current and the second AC current, and acquires information on the phase difference between the first AC current and the second AC current by calculating the difference between the phase of the first AC current and the phase of the second AC current included in the phase information. The phase information acquiring unit 15 outputs the acquired phase information (information on the phase difference) to the detection unit 17.

[0029] The current value information acquiring unit 16 acquires current value information on the current values ​​(e.g., effective value) of the first AC current and the second AC current. Specifically, the current value information acquiring unit 16 acquires current value information on each current value of the first AC current and the second AC current, and acquires information on the total current value of the first AC current and the second AC current by calculating the sum of the current value of the first AC current and the current value of the second AC current included in the current value information. The current value information acquiring unit 16 outputs the acquired current value information (information on the total current value) to the detection unit 17. Note that the "current value" in the present invention does not mean an instantaneous current value, but an amplitude value (e.g., effective value) derived from a current waveform.

[0030] 2, the detection unit 17 is configured to detect the position of an object F (e.g., a human finger) with respect to the diaphragm 11. The detection unit 17 is configured with, for example, a microcomputer. The detection unit 17 detects the position of the object F in the y direction based on the phase information, and detects the position of the object F in the z direction based on the current value information.

[0031] As shown in Fig. 3(A), when the object F is moved from position Y1 to position Y4 on the diaphragm 11, the phase difference of the second AC current relative to the first AC current changes as shown in Fig. 3(B). In Fig. 3(A), a rectangular parallelepiped reflector is used as the object F, and the position of one end of the diaphragm 11 in the y direction is Y0, the position 50 [mm] away from Y0 in the y direction is Y1, and the position 150 [mm] away from Y0 in the y direction is Y4. Then, with the bottom surface of the object F being 3 [mm] away from the top surface of the diaphragm 11 in the z direction, the center of the object F is moved from position Y1 to position Y4.

[0032] When the object F does not exist, the first ultrasonic transducer 12a and the second ultrasonic transducer 12b perform ultrasonic vibration while maintaining a resonant state with the vibration plate 11. When the resonant state is maintained, the first ultrasonic transducer 12a has a specific phase difference (for example, a phase difference of zero) between the applied AC voltage and the first AC current, and the second ultrasonic transducer 12b has a specific phase difference (for example, a phase difference of zero) between the applied AC voltage and the second AC current. However, when the object F exists nearby, the radiation impedance seen from the vibration plate 11 changes due to the resistance component of the object F. That is, the first ultrasonic transducer 12a and / or the second ultrasonic transducer 12b cannot maintain a resonant state with the vibration plate 11 and cannot maintain the specific phase difference.

[0033] For example, when an object F is present at position Y1, the second ultrasonic transducer 12b farther from the object F maintains the resonant state because the effect of the change in radiation impedance is small, but the first ultrasonic transducer 12a closer to the object F cannot maintain the resonant state because the effect of the change in radiation impedance is large. Therefore, the phase of the first AC current flowing through the first ultrasonic transducer 12a slightly lags (or leads) the phase of the applied AC voltage.

[0034] On the other hand, when the object F is present at the position Y4, the first ultrasonic transducer 12a farther from the object F maintains the resonant state because the effect of the change in radiation impedance is small, but the second ultrasonic transducer 12b closer to the object F cannot maintain the resonant state because the effect of the change in radiation impedance is large. Therefore, the phase of the second AC current flowing through the second ultrasonic transducer 12b slightly lags (or leads) the phase of the applied AC voltage.

[0035] When the object F is moved only in the y direction of the diaphragm 11, the phase difference between the first AC current and the second AC current changes at a predetermined gradient. In this embodiment, when the object F is moved from position Y1 to position Y4 of the diaphragm 11, the phase difference of the second AC current with respect to the first AC current increases as the object F approaches Y4, as shown in Fig. 3(B). The detection unit 17 can calculate the position of the object F in the y direction based on the phase information acquired from the phase information acquisition unit 15, for example, by storing data indicating the relationship between the position of the object F in the y direction and the above-mentioned phase difference in advance.

[0036] In this embodiment, the position of object F in the y direction is calculated based on phase information regarding the phase difference between the first AC current and the second AC current, so that the position of object F in the y direction can be calculated more accurately over a wider range than when the position of object F in the y direction is calculated simply based on the phase of the first AC current or the phase of the second AC current.

[0037] As shown in Fig. 4(A), when object F is moved from position Z1 to Z5 on diaphragm 11, the total current value of the first AC current and the second AC current changes as shown in Fig. 4(B). In Fig. 4(A), a rectangular parallelepiped reflector is used as object F, and Z1 is the position where the bottom surface of object F is 1 [mm] away from the top surface of diaphragm 11 in the z direction, and Z5 is the position where the top surface of object F is 24 [mm] away from the top surface of diaphragm 11 in the z direction. Between Z1 and Z5, there are Z2, Z3, and Z4.

[0038] 4B is a diagram showing the change in the total current value of the first AC current and the second AC current when the object F is moved from position Z1 to position Z5 in the range from Y2 to Y3. Note that Y2 is a position 100 [mm] away from one end of the diaphragm 11 in the y direction, and Y3 is a position 115 [mm] away.

[0039] In FIG. 4B, when the object F is moved from position Z1 to Z5 of the diaphragm 11, the total current value of the first AC current and the second AC current becomes large at positions Z2, Z3, and Z4 and their vicinity (for example, the region surrounded by a black frame in the figure). On the other hand, the total current value becomes small in other regions. This is because standing waves are generated between the diaphragm 11 and the object F at positions Z2, Z3, and Z4 and their vicinity, but no standing waves are generated between the diaphragm 11 and the object F in other regions. The standing waves are ultrasonic standing waves radiated in the z direction from the diaphragm 11 during flexural vibration.

[0040] When the object F is moved only in the z direction of the diaphragm 11, the total current value of the first AC current and the second AC current changes with a predetermined slope (for example, sinusoidal). In this embodiment, the total current value when the object F is moved from position Z1 to position Z5 of the diaphragm 11 becomes large at positions Z2, Z3, and Z4 and their vicinity. The detection unit 17 can calculate the position of the object F in the z direction based on the current value information acquired from the current value information acquisition unit 16, for example, by storing data indicating the relationship between the position of the object F in the z direction and the total current value in advance.

[0041] 5 shows the change in phase difference between the current flowing through the first ultrasonic transducer 12a and the current flowing through the second ultrasonic transducer 12b when the object F is moved in the y direction at any position Z (Z2', Z3', Z4') in the z direction. Note that Z2' is located within the black frame near Z2 in FIG. 4(B), Z3' is located within the black frame near Z3, and Z4' is located within the black frame near Z4.

[0042] The detection unit 17 can accurately calculate the position of the object F in the y-z plane by prestoring data (first data) indicating the relationship between the position of the object F in the z direction and the total current value, and data (second data) indicating the relationship between the position of the object F in the y direction and the phase difference for each arbitrary position Z in the z direction.

[0043] When the total current value changes in a sine wave shape, there are a plurality of positions Z for one total current value. For example, the total current values when Z = Z2’, Z3’, and Z4’ may all be α [A]. On the other hand, in the range from Y1 to Y4, the phase differences when Z = Z2’, Z3’, and Z4’ exist in different ranges. That is, as shown in FIG. 5, the phase difference at Y4 when Z = Z2’ < the phase difference at Y1 when Z = Z3’, and the phase difference at Y4 when Z = Z3’ < the phase difference at Y1 when Z = Z4’.

[0044] In the above case, when the current value information acquisition unit 16 acquires the total current value α [A] as the current value information and the phase information acquisition unit 15 acquires the phase difference β [°] as the phase information, the detection unit 17 first identifies (estimates) the positions in the z direction as Z = Z2’, Z3’, and Z4’ based on the first data.

[0045] Next, the detection unit 17 identifies Z having the phase difference closest to the phase difference β [°] from among Z = Z2’, Z3’, and Z4’ based on the second data, and identifies the position in the y direction from the identified Z. In FIG. 5, since Z having the phase difference closest to the phase difference β [°] is Z = Z3’, the position in the y direction can be identified as γ [mm] based on the data regarding Z = Z3’.

[0046] In FIG. 5, it is assumed that the phase difference and the position Z (the position Z estimated from the total current value) correspond one-to-one in the range from Y1 to Y4. However, when there are a plurality of positions Z for the phase difference, it is preferable to limit the range in the y direction to be specified so that the phase difference and the position Z correspond one-to-one, or to limit the range in the z direction to be specified so that the total current value and the position Z correspond one-to-one.

[0047] According to the non-contact sensor device 10A of this embodiment, the ultrasonic transducer that generates bending vibration in the vibration plate 11 is composed of two transducers, the first ultrasonic transducer 12a and the second ultrasonic transducer 12b, thereby reducing the number of parts and achieving cost reduction.

[0048] (Non-contact sensing method) Next, a non-contact sensing method according to a first embodiment of the present invention will be described.

[0049] The non-contact sensing method according to this embodiment is a method for detecting the position of an object F in a non-contact manner using the non-contact sensor device 10A, and includes a driving step, an information acquisition step, and a detection step.

[0050] In the driving step, the driving unit 13 applies AC voltages of the same frequency and phase to the first ultrasonic transducer 12a and the second ultrasonic transducer 12b, causing ultrasonic vibrations in the first ultrasonic transducer 12a and the second ultrasonic transducer 12b, and causing bending vibrations in the vibration plate 11.

[0051] In the information acquisition step, while the diaphragm 11 is performing flexural vibration, the information acquisition unit 14 acquires information about the first AC current flowing through the first ultrasonic transducer 12a and information about the second AC current flowing through the second ultrasonic transducer 12b. Specifically, the phase information acquisition unit 15 acquires information about the phase difference between the first AC current and the second AC current (phase information), and the current value information acquisition unit 16 acquires information about the total current value of the first AC current and the second AC current (current value information).

[0052] In the detection step, the detection unit 17 detects the position of the object F with respect to the diaphragm 11. Specifically, the position of the object F in the y direction is detected based on the phase information, and the position of the object F in the z direction is detected based on the current value information.

[0053] For example, if the detection unit 17 previously stores data (first data) indicating the relationship between the position of the object F in the z direction and the total current value, and data (second data) indicating the relationship between the position of the object F in the y direction and the phase difference for each arbitrary position Z in the z direction as shown in Fig. 5, the position of the object F can be detected as follows. That is, the detection unit 17 specifies the position in the z direction (position Z) based on the first data, and then specifies the position of the object F in the y direction based on the second data. This makes it possible to accurately detect the position of the object F on the yz plane.

[0054] According to the non-contact sensing method of this embodiment, a non-contact sensor device 10A is used that is composed of two ultrasonic transducers, a first ultrasonic transducer 12a and a second ultrasonic transducer 12b, which generate flexural vibrations in a diaphragm 11, so that the position of an object F can be detected non-contact without increasing the number of parts or the cost.

[0055] [Second embodiment] (Non-contact sensor device) 6 shows a non-contact sensor device 10B according to a second embodiment of the present invention. The non-contact sensor device 10B has a common configuration with the first embodiment, except that it includes a diaphragm 11' instead of the diaphragm 11, and includes an ultrasonic transducer 12 (corresponding to the "third ultrasonic transducer" of the present invention) instead of the first ultrasonic transducer 12a and the second ultrasonic transducer 12b.

[0056] The diaphragm 11' is configured to generate a flexural vibration due to ultrasonic vibration of the ultrasonic vibrator 12. The thickness of the diaphragm 11' in the z direction changes continuously in the y direction. In this embodiment, the thickness is greatest at one end (one end) in the y direction, and the thickness decreases continuously toward the other end (other end) in the y direction.

[0057] The ultrasonic transducer 12 is configured to generate ultrasonic vibrations when an AC voltage is applied, and to generate flexural vibrations in the vibration plate 11'. The ultrasonic transducer 12 is provided on the lower part of one end side of the vibration plate 11'. In this embodiment, a Langevin type transducer is used as the ultrasonic transducer 12. The position of the ultrasonic transducer 12 can be changed as appropriate as long as it is located below the vibration plate 11'.

[0058] The driving unit 13 is configured to apply an AC voltage to the ultrasonic transducer 12 so that the diaphragm 11' and the ultrasonic transducer 12 resonate.

[0059] The information acquiring unit 14 is configured to acquire information regarding the AC current flowing through the ultrasonic transducer 12 during ultrasonic vibration. The information acquiring unit 14 includes a phase information acquiring unit 15 and a current value information acquiring unit 16. The phase information acquiring unit 15 acquires phase information of the AC current flowing through the ultrasonic transducer 12, and the current value information acquiring unit 16 acquires current value information regarding the current value of the AC current.

[0060] The detection unit 17 detects the position of the object F in the y direction based on the phase information, and detects the position of the object F in the z direction based on the current value information.

[0061] In this embodiment, the thickness of the diaphragm 11' in the z direction changes continuously in the y direction, so that the ultrasonic waves emitted in the z direction from the diaphragm 11' during flexural vibration have different intensities in the y direction. Therefore, when the object F is moved in the y direction of the diaphragm 11', the phase of the AC current flowing through the ultrasonic transducer 12 changes at a predetermined gradient.

[0062] The detection unit 17 can calculate the position of the object F in the y direction based on the phase information acquired from the phase information acquisition unit 15, for example, by pre-storing data indicating the relationship between the position of the object F in the y direction and the above-mentioned phase.

[0063] Furthermore, when the object F is moved in the z direction of the vibration plate 11, the current value of the AC current flowing through the ultrasonic transducer 12 changes with a predetermined gradient (for example, sinusoidal) as in the first embodiment. The detection unit 17 can calculate the position of the object F in the z direction based on the current value information acquired from the current value information acquisition unit 16, for example, by storing data indicating the relationship between the position of the object F in the z direction and the current value in advance.

[0064] According to the non-contact sensor device 10B of this embodiment, the ultrasonic vibrator that generates flexural vibration in the diaphragm 11' is configured as a single ultrasonic vibrator 12, so that the number of parts can be reduced, leading to lower costs.

[0065] (Non-contact sensing method) Next, a non-contact sensing method according to a second embodiment of the present invention will be described.

[0066] The non-contact sensing method according to this embodiment is a method for detecting the position of an object F in a non-contact manner using a non-contact sensor device 10B, and includes a driving step, an information acquisition step, and a detection step, similarly to the first embodiment.

[0067] In the driving step, an AC voltage is applied to the ultrasonic transducer 12 by the driving unit 13, causing the ultrasonic transducer 12 to generate ultrasonic vibration, thereby causing bending vibration in the vibration plate 11'.

[0068] In the information acquisition step, while the vibration plate 11' is performing flexural vibration, the information acquisition unit 14 acquires information about the AC current flowing through the ultrasonic transducer 12. Specifically, the phase information acquisition unit 15 acquires phase information about the phase of the AC current, and the current value information acquisition unit 16 acquires current value information about the current value of the AC current.

[0069] In the detection step, the position of the object F relative to the diaphragm 11' is detected by the detection unit 17. Specifically, the position of the object F in the y direction is detected based on the phase information, and the position of the object F in the z direction is detected based on the current value information.

[0070] According to the non-contact sensing method of this embodiment, a non-contact sensor device 10B is used in which an ultrasonic transducer that generates a bending vibration in a vibration plate 11' is composed of a single ultrasonic transducer 12, so that the position of an object F can be detected non-contactly without increasing the number of parts and the cost.

[0071] [Variations] Although the embodiments of the non-contact sensor device and the non-contact sensing method according to the present invention have been described above, the present invention is not limited to the above-mentioned embodiments.

[0072] The non-contact sensor device of the present invention comprises a vibration plate, an ultrasonic vibrator that generates a bending vibration in the vibration plate, a driving unit that applies an AC voltage to the ultrasonic vibrator, a phase information acquisition unit that acquires phase information of the AC current flowing through the ultrasonic vibrator, and a detection unit that detects the position of an object relative to the vibration plate, and the configuration of the detection unit can be modified as appropriate as long as it detects the position of an object in the propagation direction of the bending vibration based on the phase information.

[0073] The non-contact sensing method of the present invention includes a driving step of applying an AC voltage to an ultrasonic transducer provided on a diaphragm to generate a flexural vibration in the diaphragm through ultrasonic vibration of the ultrasonic transducer, an information acquisition step of acquiring phase information of the AC current flowing through the ultrasonic transducer, and a detection step of detecting the position of an object relative to the diaphragm, and the configuration can be modified as appropriate so long as the detection step detects the position of the object in the propagation direction of the flexural vibration based on the phase information.

[0074] The material and / or dimensions of the diaphragm may be changed as appropriate as long as the diaphragm is configured to generate a flexural vibration due to the ultrasonic vibration of the ultrasonic vibrator. The diaphragm may be configured, for example, of a glass plate. In addition, the diaphragm may be subjected to any processing as long as a flexural vibration is generated.

[0075] In the second embodiment, the thickness of diaphragm 11' is changed continuously in the y direction, but the mechanical rigidity (bending rigidity) of the diaphragm may be changed continuously in the y direction by adding or changing configurations other than the thickness of the diaphragm. For example, a plurality of grooves may be formed in the diaphragm and the groove width ratio may be changed in the y direction, a plurality of holes may be formed in the diaphragm and the hole pitch may be changed in the y direction, or the diaphragm may be made of a composite material (e.g., metal and glass) and the material ratio may be changed in the y direction.

[0076] The ultrasonic transducer may be other than the Langevin type transducer. For example, an ultrasonic transducer made of lead zirconate titanate (PZT) may be attached to the lower surface of the vibration plate. The number of ultrasonic transducers may be changed as appropriate depending on the dimensions of the vibration plate.

[0077] In the first embodiment, the detection unit 17 calculates the position of the object F in the z direction based on current value information regarding the total current value of the first AC current and the second AC current acquired from the current value information acquisition unit 16, but the position of the object F in the z direction may also be calculated based on current value information regarding the current value of the first AC current or the second AC current. [Explanation of symbols]

[0078] 10A, 10B Non-contact sensor device 11 Diaphragm 12 Ultrasonic transducer 12a First ultrasonic transducer 12b Second ultrasonic transducer 13 Drive unit 14 Information acquisition department 15 Phase information acquisition section 16 Current value information acquisition section 17 Detection unit

Claims

1. A non-contact sensor device that detects the position of an object in a non-contact manner, A diaphragm; an ultrasonic vibrator that generates a flexural vibration in the vibration plate; A drive unit that applies an AC voltage to the ultrasonic transducer; a phase information acquisition unit that acquires phase information of an alternating current flowing through the ultrasonic transducer; A detection unit that detects a position of the object relative to the vibration plate; Equipped with The non-contact sensor device, wherein the detection unit detects a position of the object in a propagation direction of the flexural vibration based on the phase information.

2. A current value information acquisition unit that acquires current value information of the AC current, The non-contact sensor device according to claim 1 , wherein the detection section detects a position of the object in a vibration direction of the flexural vibration based on the current value information.

3. The ultrasonic transducer is A first ultrasonic transducer disposed on one side of the vibration plate in the propagation direction; A second ultrasonic transducer disposed on the other side of the vibration plate in the propagation direction; Including, The non-contact sensor device according to claim 1 or 2, characterized in that the phase information acquisition unit acquires, as the phase information, information regarding a phase difference between a first AC current flowing through the first ultrasonic transducer and a second AC current flowing through the second ultrasonic transducer.

4. The ultrasonic transducer comprises a single third ultrasonic transducer, The diaphragm has a mechanical stiffness that changes in the propagation direction, 3. The non-contact sensor device according to claim 1, wherein the phase information acquisition unit acquires, as the phase information, information relating to a phase of a third AC current flowing through the third ultrasonic transducer.

5. 5. The non-contact sensor device according to claim 4, wherein the thickness of the diaphragm changes in the propagation direction.

6. A non-contact sensing method for detecting a position of an object in a non-contact manner, comprising: a driving step of applying an AC voltage to an ultrasonic vibrator provided on a vibration plate to generate a bending vibration in the vibration plate by ultrasonic vibration of the ultrasonic vibrator; An information acquisition step of acquiring phase information of an alternating current flowing through the ultrasonic transducer; a sensing step of sensing a position of the object relative to the diaphragm; Including, A non-contact sensing method, wherein in the detection step, a position of the object in a propagation direction of the flexural vibration is detected based on the phase information.

7. In the information acquisition step, current value information of the AC current is acquired, 7. The non-contact sensing method according to claim 6, wherein in the detecting step, a position of the object in a vibration direction of the flexural vibration is detected based on the current value information.

8. The ultrasonic transducer is A first ultrasonic transducer disposed on one side of the vibration plate in the propagation direction; A second ultrasonic transducer disposed on the other side of the vibration plate in the propagation direction; Including, The non-contact sensing method according to claim 6 or 7, characterized in that in the information acquisition step, information regarding a phase difference between a first AC current flowing through the first ultrasonic transducer and a second AC current flowing through the second ultrasonic transducer is acquired as the phase information.

9. The ultrasonic transducer comprises a single third ultrasonic transducer, The diaphragm has a mechanical stiffness that changes in the propagation direction, 8. The non-contact sensing method according to claim 6, wherein in the information acquiring step, information about a phase of a third AC current flowing through the third ultrasonic transducer is acquired as the phase information.

10. The non-contact sensing method according to claim 9 , wherein the diaphragm has a thickness that varies in the propagation direction.

Images