Driving circuit, electronic device, and method for driving vibration device

Abstract

To provide a driving circuit capable of highly efficiently driving a vibration device, and an electronic device.SOLUTION: A driving circuit comprises: a signal generation unit which generates a driving signal so as to have a drive frequency and transmits the generated driving signal to a vibration device which vibrates according to the driving signal; a detection unit which detects vibration information about the vibration of the vibration device from the vibration device; and a control unit which determines the drive frequency on the basis of the vibration information detected by the detection unit and transmits the determined drive frequency to the signal generation unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drive circuit, an electronic device, and a method for driving a vibration device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, electronic devices are known that include a vibration device and a drive circuit for driving a vibration device such as a haptic device.

[0003] In this regard, Patent Document 1 discloses an electronic pen that is provided with a vibration device and reproduces the resistance of various virtual writing surfaces by the vibration of the vibration device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2013 / 0307829 Summary of the Invention [Problem to be solved by the invention]

[0005] A vibration device has the highest power consumption efficiency when the drive frequency for driving the vibration device matches the resonant frequency of the vibration device. However, in the technology described in Patent Document 1, since the electronic device drives the vibration device with a fixed drive frequency, there is a problem that the efficiency of power consumption decreases due to variations in the resonant frequency caused by manufacturing errors or differences in the environment in which the vibration device is installed.

[0006] The present invention has been made in consideration of such problems, and has a purpose to provide a drive circuit and electronic device that can drive a vibration device with high efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, the first driving circuit of the present invention is a driving circuit that drives a vibration device that vibrates in response to a driving signal, and includes a signal generating unit that generates the driving signal to have a driving frequency and transmits the generated driving signal to the vibration device, a detection unit that detects vibration information related to the vibration of the vibration device from the vibration device, and a control unit that determines the driving frequency based on the vibration information detected by the detection unit and transmits the determined driving frequency to the signal generating unit.

[0008] In the drive circuit according to the second aspect of the present invention, the vibration information is a vibration frequency at which the vibration device vibrates.

[0009] In the drive circuit according to a third aspect of the present invention, the control section determines the drive frequency so that the drive frequency approaches the vibration frequency.

[0010] In addition, in the drive circuit according to a fourth aspect of the present invention, the detection section detects the vibration information from the vibration device after the signal generation section stops transmitting the drive signal to the vibration device.

[0011] In the drive circuit according to a fifth aspect of the present invention, the vibration information is a phase difference between a vibration signal generated by vibration of the vibrating device and the drive signal.

[0012] In the drive circuit according to a sixth aspect of the present invention, the control section determines the drive frequency so that the phase difference approaches a predetermined value.

[0013] In addition, in the drive circuit according to a seventh aspect of the present invention, the vibration information is an amplitude of a vibration signal generated by vibration of the vibration device.

[0014] In addition, in the drive circuit according to an eighth aspect of the present invention, the control section determines the drive frequency so that the amplitude increases.

[0015] In addition, the ninth electronic device of the present invention comprises a vibration device that vibrates in response to a drive signal, a signal generating unit that generates the drive signal to have a drive frequency and transmits the generated drive signal to the vibration device, a detection unit that detects vibration information related to the vibration of the vibration device from the vibration device, and a drive circuit having a control unit that determines the drive frequency based on the vibration information detected by the detection unit and transmits the determined drive frequency to the signal generating unit.

[0016] Moreover, the electronic device according to the tenth aspect of the present invention functions as an electronic pen.

[0017] Furthermore, a driving method for a vibration device according to an eleventh aspect of the present invention is a driving method for driving a vibration device that vibrates in response to a drive signal, the driving method including generating the drive signal to have a drive frequency, transmitting the generated drive signal to the vibration device, detecting vibration information relating to the vibration of the vibration device from the vibration device, and determining the drive frequency based on the detected vibration information. Effect of the Invention

[0018] According to the present invention, the drive circuit and electronic device can drive the vibration device with high efficiency. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a diagram illustrating a first example of a drive circuit. [Diagram 2] 4 is a flowchart showing a series of operations of the drive circuit of the first example. [Diagram 3] FIG. 13 is a diagram illustrating a second example of a drive circuit. [Figure 4A] 11 is a graph showing the relationship between the ratio of the drive frequency and the vibration frequency and the phase difference when the vibration device is vibrated. [Figure 4B] 11 is a graph showing the relationship between the ratio of the drive frequency to the vibration frequency and the amplitude magnification when the vibration device is vibrated. [Diagram 5]10 is a flowchart showing a series of operations of a drive circuit according to a second example. [Figure 6] FIG. 1 is a diagram illustrating an example of an electronic device including a drive circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention (hereinafter, referred to as a "first embodiment" or a "second embodiment") will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components and steps in each drawing are denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0021] ---First embodiment--- First, the first embodiment will be described.

[0022] <Configuration> 1 is a diagram showing a first example of a driving circuit. The driving circuit 10A drives a vibration device 20 such as a haptic device. When driving the vibration device 20, the driving circuit 10A detects vibration information related to the vibration of the vibration device 20 from the vibration device 20, and reflects the contents of the detected vibration information in the control of driving the vibration device 20. The driving circuit 10A includes, for example, a signal generating unit 11, a detecting unit 12A, a control unit 13A, and an output circuit 14A. The driving circuit 10A is mounted on, for example, an electronic device using the vibration device 20.

[0023] Examples of electronic devices in which the driving circuit 10A is mounted include electronic pens, user interface devices installed in automobiles, game console controllers, mobile phones, smartphones, tablets, buzzers, massagers, toys with vibration functions, etc. Examples of electronic pens in which the driving circuit 10A is mounted include styluses for tablets and pen-type devices for VR (Virtual Reality).

[0024] The vibration device 20 is a haptic device such as an LRA (Linear Resonant Actuator) or an eccentric motor, and vibrates according to the drive control of the drive circuit 10A. When the short-circuit control elements SW1 and SW2 of the output circuit 14A are short-circuited, the vibration device 20 vibrates in response to the application of a drive signal dr, the signal of which is amplified via the output circuit 14A, to both ends of the vibration device 20. On the other hand, when the short-circuit control elements SW1 and SW2 of the output circuit 14A are open, the detection unit 12A detects vibration information related to the vibration of the vibration device 20 from the fluctuation in the potential difference between both ends of the vibration device 20 caused by the vibration of the vibration device 20. In addition, one end of the vibration device 20 is connected to the other end of the short-circuit control element SW1 and one of the two input terminals of the detection unit 12A, and the other end is connected to one end of the short-circuit control element SW2 and the other of the two input terminals of the detection unit 12A.

[0025] The signal generating unit 11 generates the drive signal dr to have a drive frequency fdr, and transmits the generated drive signal dr to the vibration device 20. Specifically, the signal generating unit 11 generates the drive signal dr to have a drive frequency fdr indicated by the feedback signal fb transmitted from the control unit 13A, and transmits the generated drive signal dr to the vibration device 20 via the output circuit 14A. The drive signal dr transmitted from the signal generating unit 11 is input to logical negation circuits INV1 and INV3 of the output circuit 14A.

[0026] The output circuit 14A converts the drive signal dr transmitted from the signal generating unit 11 into a differential signal that alternates in opposite phases, further amplifies the signal, and outputs it to the vibration device 20. The output circuit 14A is configured to include, for example, logical negation circuits INV1 to INV3 and short-circuit control elements SW1 and SW2.

[0027] The logical negation circuits INV1 to INV3 are inverter circuits including transistors, for example. The logical negation circuit INV1 performs a logical negation operation on the drive signal dr transmitted from the signal generating unit 11, and outputs the signal obtained by the operation to the logical negation circuit INV2.

[0028] The logical negation circuit INV2 performs a logical negation operation on the signal output from the logical negation circuit INV1, and outputs the signal obtained by the operation via the short-circuit control element SW1 to one end of the vibration device 20. The logical negation circuit INV2 is configured to include transistors TR1 and TR2.

[0029] The logical negation circuit INV3 performs a logical negation operation on the drive signal dr transmitted from the signal generating unit 11, and outputs the signal obtained by the operation via the short-circuit control element SW2 to the other end of the vibration device 20. The logical negation circuit INV3 also includes transistors TR3 and TR4.

[0030] The transistors TR1 and TR3 are, for example, P-type MOS-FETs. The transistors TR1 and TR3 supply the potential supplied to the source terminal to the drain terminal or stop the supply according to a signal input to the gate terminal. Specifically, when the state of the signal input to the gate terminal is low, the transistors TR1 and TR3 supply the potential supplied to the source terminal to the drain terminal, and when the potential of the signal input to the gate terminal is high, the transistors TR1 and TR3 stop the supply.

[0031] The transistors TR2 and TR4 are, for example, N-type MOS-FETs. The transistors TR2 and TR4 extract or stop the extraction of electric charges from the drain terminal to the source terminal according to a signal input to the gate terminal. Specifically, when the state of the signal input to the gate terminal is high, the transistors TR2 and TR4 extract electric charges from the drain terminal to the source terminal, while when the state of the signal input to the gate terminal is low, the transistors TR2 and TR4 stop the extraction.

[0032] The transistor TR1 has a gate terminal connected to the output terminal of the logical NOT circuit INV1 and the gate terminal of the transistor TR2, a source terminal supplied with the power supply potential VDD, and a drain terminal connected to the drain terminal of the transistor TR2 and one end of the short-circuit control element SW1.

[0033] The transistor TR2 has a gate terminal connected to the output terminal of the logical NOT circuit INV1, a source terminal supplied with the ground potential GND, and a drain terminal connected to the drain terminal of the transistor TR1 and one end of the short-circuit control element SW1.

[0034] The gate terminal of transistor TR3 is connected to the output terminal of the signal generating unit 11, the input terminal of the logical NOT circuit INV1, and the gate terminal of transistor TR4, the source terminal is supplied with the power supply potential VDD, and the drain terminal is connected to the drain terminal of transistor TR4 and the other end of the short-circuit control element SW2.

[0035] The transistor TR4 has a gate terminal connected to the output terminal of the signal generating unit 11, an input terminal of the logical NOT circuit INV1, and a gate terminal of the transistor TR3, a source terminal to which the ground potential GND is supplied, and a drain terminal connected to the drain terminal of the transistor TR3 and the other end of the short-circuit control element SW2.

[0036] The short-circuit control elements SW1 and SW2 are, for example, switch elements or transistors, and output the drive signal dr with the amplified signal from the output circuit 14A or stop the output according to the control of the control unit 13A. Specifically, the short-circuit control element SW1 has one end connected to the drain terminals of the transistors TR1 and TR2, while the other end connected to one end of the vibration device 20 and one of the two input terminals of the detection unit 12A, and short-circuits or opens both ends according to the control of the control unit 13A. In addition, the short-circuit control element SW2 has one end connected to the other end of the vibration device 20 and the other of the two input terminals of the detection unit 12A, while the other end connected to the drain terminals of the transistors TR3 and TR4, and short-circuits or opens both ends according to the control of the control unit 13A.

[0037] The detection unit 12A detects vibration information related to the vibration of the vibration device 20 from the vibration device 20. Specifically, after the signal generation unit 11 stops transmitting the drive signal dr to the vibration device 20, the detection unit 12A acquires a time transition of the potential difference between both ends of the vibration device 20 as a vibration signal, and detects the frequency, amplitude, and the like of the acquired signal as vibration information. Note that the frequency of the signal acquired by the detection unit 12A indicates the vibration frequency fres of the vibration device 20. The detection unit 12A outputs a detection signal res including the detected vibration information to the control unit 13A.

[0038] The control unit 13A determines the drive frequency fdr based on vibration information such as the vibration frequency fres and amplitude detected by the detection unit 12A, and transmits the determined drive frequency fdr to the signal generation unit 11 as a feedback signal fb. Specifically, the control unit 13A determines the drive frequency fdr so that the drive frequency fdr approaches the vibration frequency fres. The control unit 13A also determines the drive frequency fdr so that the amplitude indicated by the vibration information increases. The control unit 13A also controls the transmission of the drive signal dr by the signal generation unit 11 and the stop of the transmission, the short-circuiting and opening operations of the short-circuit control elements SW1 and SW2, and the detection of vibration information from the vibration device 20 by the detection unit 12A and the stop of the detection.

[0039] Next, an example of an electronic device equipped with the drive circuit 10A according to the first embodiment will be described. FIG. 6 is a diagram showing an example of an electronic device 1 equipped with the drive circuit 10A. The electronic device 1 shown in FIG. 6 is, for example, an electronic pen such as a stylus for a tablet or a pen-type device for VR. The electronic device 1 includes, for example, the drive circuit 10A, a vibration device 20, an input circuit 30, a transmission / reception circuit 40, and a control circuit 50. The configurations and operations of the drive circuit 10A and the vibration device 20 are as described above, and therefore will not be described here.

[0040] The input circuit 30 is a circuit for converting an operation received from an operator of the electronic device 1 via an input interface into a signal. The input circuit 30 converts the operation received from the operator into a signal including information about the operation content, and transmits the converted signal to the control circuit 50.

[0041] The transmission / reception circuit 40 is a circuit for performing communication between the electronic device 1 and devices other than the electronic device 1. The transmission / reception circuit 40 transmits and receives signals indicating the position of the pen and the degree of pressure applied by the pen to the tablet, for example, between a tablet, a VR device, etc. Also, the transmission / reception circuit 40 receives a signal to be transmitted from the control circuit 50 and outputs the received signal to the control circuit 50.

[0042] The control circuit 50 is a circuit for controlling the operation of the electronic device 1. The control circuit 50 generates a signal for transmission in response to a signal transmitted from the input circuit 30 or a signal received from the transmission / reception circuit 40, and outputs the generated signal to the transmission / reception circuit 40. The control circuit 50 also outputs a command related to the vibration operation of the vibration device 20 to the drive circuit 10A in response to a signal transmitted from the input circuit 30 or a signal received from the transmission / reception circuit 40. The control circuit 50 also performs various other controls necessary for the electronic device 1 to function as an electronic pen.

[0043] The electronic device 1 configured as above causes the drive circuit 10A to execute a process of calibrating the drive frequency fdr so that the drive frequency fdr approaches the vibration frequency fres when the electronic device 1 is started up or when the electronic device 1 returns from a sleep mode for saving battery power, etc. After the calibration process of the drive frequency fdr is completed, the electronic device 1 executes a process according to an operation by an operator of the electronic device 1 or a command from another device with which the electronic device 1 transmits and receives data.

[0044] Furthermore, when the electronic device 1 functions as an electronic pen, the electronic device 1 drives the drive circuit 10A to change the degree of vibration of the vibration device 20 according to the pressure on the tablet when the operator touches the electronic device 1 to the tablet to indicate a position. This allows the electronic device 1, although being a digital pen, to reproduce the writing and drawing comfort of an analog pen.

[0045] Furthermore, when the electronic device 1 functions as a VR pen, the electronic device 1 drives the drive circuit 10A so as to change the degree of vibration of the vibration device 20 according to the moving speed and moving acceleration relative to the virtual plane when the operator designates a position on the virtual plane on which the electronic device 1 is positioned in space. This allows the electronic device 1, although a VR pen, to reproduce the writing and drawing comfort of an analog pen.

[0046] <Flow of operations> The drive circuit 10A according to the first embodiment, the components of the electronic device 1, and the vibration device 20 have been described above. Next, a flow of a series of operations of the drive circuit 10A according to the first embodiment will be described. Fig. 2 is a flowchart showing the flow of a series of operations of the drive circuit 10A of the first example.

[0047] (Step SP10) The drive circuit 10A controls the control unit 13A to short-circuit both ends of the short-circuit control elements SW1 and SW2, respectively. Then, the process proceeds to step SP12.

[0048] (Step SP12) The driving circuit 10A causes the signal generating unit 11 to generate a driving signal dr by the control unit 13A, and applies the generated driving signal dr to the vibration device 20 via the output circuit 14A for a predetermined time or more. The signal generating unit 11 generates the driving signal dr so as to have a driving frequency fdr that is an initial value determined by the control unit 13A or that is predetermined. Then, the process proceeds to the process of step SP14.

[0049] (Step SP14) The drive circuit 10A causes the control unit 13A to stop the generation and application of the drive signal dr by the signal generating unit 11. Next, the drive circuit 10A controls both ends of the short control elements SW1 and SW2 to be in an open state by the control unit 13A. Then, the process proceeds to step SP16.

[0050] (Step SP16) The drive circuit 10A causes the control unit 13A to acquire the time transition of the potential difference across the vibration device 20 as a vibration signal in the detection unit 12A, and detects the frequency of the acquired vibration signal as the vibration frequency fres of the vibration device 20. Then, the process proceeds to step SP18.

[0051] (Step SP18) The driving circuit 10A calculates the difference between the driving frequency fdr and the vibration frequency fres by the control unit 13A, and judges whether the calculated difference is within a predetermined range. The predetermined range may be, for example, a range between an upper limit value and a lower limit value that are predetermined for the calculated difference, or a range between an upper limit value and a lower limit value that are predetermined for the ratio of the calculated difference to the driving frequency fdr (for example, ±1% for the driving frequency fdr). If the judgment is negative, the driving circuit 10A judges that the driving frequency fdr is inappropriate for the vibration device 20, and the process proceeds to the process of step SP20. On the other hand, if the judgment is positive, the driving circuit 10A judges that the driving frequency fdr is appropriate for the vibration device 20, and the series of processes shown in FIG. 2 ends.

[0052] (Step SP20) The drive circuit 10A determines whether the drive frequency fdr is lower than the vibration frequency fres by the control unit 13A. If the determination is positive, the process proceeds to step SP22. If the determination is negative, the process proceeds to step SP24.

[0053] (Step SP22) The driving circuit 10A increases the driving frequency fdr from the current value by the control unit 13A. When increasing the driving frequency fdr, the control unit 13A may increase it by a predetermined value, may increase it by a predetermined ratio, or may increase it to the same value as the vibration frequency fres. Then, the process returns to the process of step SP10.

[0054] (Step SP24) The driving circuit 10A causes the control unit 13A to reduce the driving frequency fdr from the current value. When reducing the driving frequency fdr, the control unit 13A may reduce it by a predetermined value, may reduce it by a predetermined ratio, or may reduce it to the same value as the vibration frequency fres. Then, the process returns to the process of step SP10.

[0055] <Effects> As described above, in the first embodiment, the drive circuit 10A drives the vibration device 20 to vibrate in response to a drive signal dr, and includes a signal generation unit 11 that generates the drive signal dr to have a drive frequency fdr and transmits the generated drive signal dr to the vibration device 20, a detection unit 12A that detects vibration information related to the vibration of the vibration device 20 from the vibration device 20, and a control unit 13A that determines the drive frequency fdr based on the vibration information detected by the detection unit 12A and transmits the determined drive frequency fdr to the signal generation unit 11.

[0056] According to this configuration, the drive circuit 10A determines the drive frequency fdr based on the vibration information of the vibration device 20, and therefore, the vibration device 20 can be driven with high efficiency.

[0057] In the first embodiment, the vibration information is the vibration frequency fres at which the vibration device 20 vibrates.

[0058] According to this configuration, the drive circuit 10A determines the drive frequency fdr based on the vibration frequency fres of the vibration device 20, and therefore, the vibration device 20 can be driven with high efficiency.

[0059] Moreover, in the first embodiment, the control unit 13A determines the drive frequency fdr so that the drive frequency fdr approaches the vibration frequency fres.

[0060] According to this configuration, the drive circuit 10A brings the drive frequency fdr closer to the vibration frequency fres of the vibration device 20, and therefore can drive the vibration device 20 with high efficiency.

[0061] In the first embodiment, the vibration information is the amplitude of a vibration signal generated by the vibration of the vibration device 20.

[0062] According to this configuration, the drive circuit 10A determines the drive frequency fdr based on the amplitude of the vibration signal, and therefore, the vibration device 20 can be driven with high efficiency.

[0063] Moreover, in the first embodiment, the control unit 13A determines the drive frequency fdr so that the amplitude of the vibration signal increases.

[0064] According to this configuration, the drive circuit 10A determines the drive frequency fdr so that the amplitude of the vibration signal increases, and therefore the vibration device 20 can be driven with high efficiency.

[0065] In addition, in the first embodiment, the electronic device 1 includes a vibration device 20 that vibrates in response to a drive signal dr, a signal generating unit 11 that generates a drive signal dr to have a drive frequency fdr and transmits the generated drive signal dr to the vibration device 20, a detection unit 12A that detects vibration information related to the vibration of the vibration device 20 from the vibration device 20, and a drive circuit 10A having a control unit 13A that determines the drive frequency fdr based on the vibration information detected by the detection unit 12A and transmits the determined drive frequency fdr to the signal generating unit 11.

[0066] According to this configuration, the electronic device 1 determines the drive frequency fdr based on the vibration information of the vibration device 20, and therefore can drive the vibration device 20 with high efficiency.

[0067] In the first embodiment, the electronic device 1 functions as an electronic pen.

[0068] According to this configuration, when an electronic pen including the vibration device 20 is used, the electronic device 1 determines the drive frequency fdr based on the vibration information, and therefore can drive the vibration device 20 of the electronic pen with high efficiency.

[0069] In addition, in the first embodiment, the driving method of the vibration device 20 is a driving method for driving the vibration device 20 to vibrate in accordance with a drive signal dr, and includes generating a drive signal dr to have a drive frequency fdr, transmitting the generated drive signal dr to the vibration device 20, detecting vibration information related to the vibration of the vibration device 20 from the vibration device 20, and determining the drive frequency fdr based on the detected vibration information.

[0070] According to this method, the method of driving the vibration device 20 determines the drive frequency fdr based on the vibration information of the vibration device 20, and therefore the vibration device 20 can be driven with high efficiency.

[0071] --- Second embodiment --- Next, a second embodiment will be described.

[0072] <Configuration> 3 is a diagram showing a second example of the drive circuit. The drive circuit 10B is configured by, for example, replacing the output circuit 14A with an output circuit 14B, replacing the detection unit 12A with a detection unit 12B, and replacing the control unit 13A with a control unit 13B, in the drive circuit 10A. Note that the signal generation unit 11 is the same as in the first embodiment, except that it transmits the generated drive signal dr not only to the output circuit 14A but also to the detection unit 12B, and therefore a description thereof will be omitted.

[0073] The vibration device 20 is similar to the first embodiment, and vibrates according to the drive control of the drive circuit 10A. When the drive signal dr, which is amplified via the output circuit 14B, is applied to both ends of the vibration device 20, the vibration device 20 vibrates in response to the application. In addition, one end of the vibration device 20 is connected to the drain terminals of the transistors TR1 and TR2 of the output circuit 14B, and the other end is connected to the drain terminals of the transistors TR3 and TR4 of the output circuit 14B and the input terminal of the detection unit 12B.

[0074] The output circuit 14B is configured by excluding the short-circuit control elements SW1 and SW2 from the output circuit 14A. The logical negation circuit INV2 in the output circuit 14B performs a logical negation operation on the signal output from the logical negation circuit INV1, and outputs the signal on which the operation has been performed to one end of the vibration device 20. The logical negation circuit INV3 in the output circuit 14B performs a logical negation operation on the drive signal dr transmitted from the signal generating unit 11, and outputs the signal on which the operation has been performed to the other end of the vibration device 20.

[0075] The detection unit 12B detects vibration information related to the vibration of the vibrating device 20 from the vibrating device 20. Specifically, the detection unit 12B starts detecting the vibration information of the vibrating device 20 based on the drive signal dr being transmitted from the signal generation unit 11 to the output circuit 14B and the detection unit 12B. Here, the detection unit 12B detects, as the vibration information, a phase difference θ between the drive signal dr and a vibration signal which is a time transition of the potential of the other end of the vibrating device 20, the amplitude of the vibration signal, and the like. In addition, the detection unit 12B outputs a detection signal res including the detected vibration information to the control unit 13B.

[0076] In addition, the detection unit 12B detects the phase difference θ between the drive signal dr and the vibration signal using, for example, a phase locked loop circuit such as a PLL (phase locked loop). In addition, the detection unit 12B measures, for example, the time from the rising timing of the potential of the drive signal dr to the rising timing of the potential of the vibration signal. The detection unit 12B may calculate the phase difference θ by dividing the measured time by the period of the drive signal dr or the vibration signal and converting the division result into a phase difference.

[0077] The control unit 13A determines the drive frequency fdr based on vibration information such as the phase difference θ and the amplitude detected by the detection unit 12B, and transmits the determined drive frequency fdr to the signal generation unit 11. Specifically, the control unit 13B determines the drive frequency fdr so that the absolute value of the phase difference θ approaches a value of π / 2, for example. The control unit 13B also determines the drive frequency fdr so that the amplitude indicated by the vibration information increases. The control unit 13B also controls the transmission of the drive signal dr by the signal generation unit 11 and the stop of the transmission, and the detection of vibration information from the vibrating device 20 by the detection unit 12B and the stop of the detection.

[0078] 4A and 4B, the relationship between the ratio of the drive frequency fdr and the vibration frequency fres, and the phase difference θ and the amplitude magnification when the vibration device 20 is vibrated will be described. Fig. 4A is a graph showing the relationship between the ratio of the drive frequency fdr and the vibration frequency fres, and the phase difference θ when the vibration device 20 is vibrated. Fig. 4B is a graph showing the relationship between the ratio of the drive frequency fdr and the vibration frequency fres, and the amplitude magnification when the vibration device 20 is vibrated.

[0079] 4A, the ratio of the drive frequency fdr to the vibration frequency fres is 1.0 when the phase difference θ is π / 2, regardless of whether the vibration damping ratio of the vibration device 20 is 0, 0.2, 0.5, or 1.0. In other words, when the phase difference θ is π / 2, the drive frequency fdr is approximately equal to the vibration frequency fres.

[0080] 4B, the amplitude magnification increases as the ratio of the drive frequency fdr to the vibration frequency fres approaches 1.0, regardless of whether the vibration damping ratio of the vibration device 20 is 0, 0.2, 0.5, or 1.0. The amplitude magnification is approximately maximum when the drive frequency fdr is slightly higher than the vibration frequency fres.

[0081] <Flow of operations> The components of the drive circuit 10B according to the second embodiment and the vibration device 20 have been described above. Next, a flow of a series of operations of the drive circuit 10B according to the second embodiment will be described. Fig. 5 is a flowchart showing the flow of a series of operations of the drive circuit 10B of the second example.

[0082] (Step SP50) The driving circuit 10B generates a driving signal dr in the signal generating unit 11 by the control unit 13B, and applies the generated driving signal dr to the vibration device 20 via the output circuit 14B for a predetermined time or more. The signal generating unit 11 generates the driving signal dr so as to have a driving frequency fdr that is an initial value determined by the control unit 13B or that is predetermined. Then, the process proceeds to the process of step SP52.

[0083] (Step SP52) The drive circuit 10B causes the control unit 13B to acquire the time transition of the potential at the other end of the vibration device 20 as a vibration signal in the detection unit 12B, and detects the phase difference θ between the acquired vibration signal and the drive signal dr. Then, the process proceeds to step SP54.

[0084] (Step SP54) The driving circuit 10B determines whether the phase difference θ is within a predetermined range by the control unit 13B. The predetermined range is, for example, a range between an upper limit value and a lower limit value that are predetermined based on π / 2. The upper limit value and the lower limit value are, for example, π / 2±1%. If the determination is negative, the driving circuit 10B determines that the driving frequency fdr is inappropriate for the vibration device 20, and the process proceeds to step SP56. On the other hand, if the determination is positive, the driving circuit 10B determines that the driving frequency fdr is appropriate for the vibration device 20, and the series of processes shown in FIG. 5 ends.

[0085] (Step SP56) The driving circuit 10B determines, by the control unit 13B, whether or not the phase difference θ is greater than 0 and less than π / 2. If the determination is affirmative, the process proceeds to step SP58. On the other hand, if the determination is negative, the process proceeds to step SP60.

[0086] (Step SP58) The driving circuit 10B increases the driving frequency fdr from the current value by the control unit 13B. When increasing the driving frequency fdr, the control unit 13B may increase it by a predetermined value or by a predetermined ratio. Then, the process returns to the process of step SP52.

[0087] (Step SP60) The drive circuit 10B causes the control unit 13B to reduce the drive frequency fdr from the current value. When reducing the drive frequency fdr, the control unit 13B may reduce it by a predetermined value or by a predetermined ratio. Then, the process returns to step SP52.

[0088] <Effects> As described above, in the second embodiment, the vibration information is the phase difference θ between the vibration signal generated by the vibration of the vibrating device 20 and the drive signal dr.

[0089] According to this configuration, the drive circuit 10B determines the drive frequency fdr based on the phase difference θ between the vibration signal and the drive signal dr, and therefore can drive the vibration device 20 with high efficiency. In addition, the drive frequency fdr can be determined while the drive signal dr is being applied.

[0090] Moreover, in the second embodiment, the control unit 13B determines the drive frequency fdr so that the phase difference θ approaches a predetermined value (for example, π / 2).

[0091] According to this configuration, the drive circuit 10B determines the drive frequency fdr so that the phase difference θ approaches a predetermined value, and therefore can highly efficiently drive the vibration device 20. In addition, the drive frequency fdr can be determined while the drive signal dr is being applied.

[0092] In the second embodiment, the vibration information is the amplitude of a vibration signal generated by the vibration of the vibration device 20.

[0093] According to this configuration, the drive circuit 10B determines the drive frequency fdr based on the amplitude of the vibration signal, and therefore can highly efficiently drive the vibration device 20. In addition, the drive frequency fdr can be determined while the drive signal dr is being applied.

[0094] Moreover, in the second embodiment, the control unit 13B determines the drive frequency fdr so that the amplitude of the vibration signal increases.

[0095] According to this configuration, the drive circuit 10B determines the drive frequency fdr so that the amplitude of the vibration signal increases, and therefore, it is possible to highly efficiently drive the vibration device 20. In addition, the drive frequency fdr can be determined while the drive signal dr is being applied.

[0096] --- Variation --- The present invention is not limited to the above-described embodiment. In other words, the above-described embodiment may be modified by a person skilled in the art as appropriate, and the modifications may be included within the scope of the present invention as long as they include the characteristics of the present invention. In addition, the elements of the above-described embodiment and the modifications described below may be combined to the extent technically possible, and the combinations of these may be included within the scope of the present invention as long as they include the characteristics of the present invention.

[0097] For example, in the first embodiment, the detection unit 12A acquires the time transition of the potential difference between both ends of the vibration device 20 as the vibration signal, but is not limited to this. The detection unit 12A may acquire the time transition of the potential of one end of the vibration device 20 as the vibration signal.

[0098] According to this configuration, the drive circuit 10A refers to the potential at one of both ends of the vibration device 20, so that components for processing differential signals can be reduced, and the vibration device 20 can be driven at low cost and with high efficiency.

[0099] In the second embodiment, the detection unit 12B acquires the time transition of the potential at the other end of the vibration device 20 as a vibration signal, but is not limited to this. The detection unit 12B may acquire the time transition of the potential difference at both ends of the vibration device 20 as a vibration signal.

[0100] According to this configuration, the drive circuit 10A refers to the potential difference between both ends of the vibration device 20, and therefore, the vibration device 20 can be driven with high accuracy and high efficiency.

[0101] In the first embodiment, the electronic device 1 increases or decreases the drive frequency fdr in the process of calibrating the drive frequency fdr so that the drive frequency fdr approaches the vibration frequency fres, but this is not limited to this. The electronic device 1 may also increase or decrease the drive frequency fdr so that the drive frequency fdr approaches the vibration frequency fres in a phase in which the electronic device 1 receives an operation by an operator or a command from another electronic device after performing a calibration process of the drive frequency fdr at the timing of startup or the timing of release from a sleep mode.

[0102] Specifically, the electronic device 1 controls the short-circuit control elements SW1 and SW2 to a short-circuit state by the drive circuit 10A. Next, the electronic device 1 causes the drive circuit 10A to acquire the time transition of the potential difference between both ends of the vibration device 20 as a vibration signal, detects the amplitude of the acquired vibration signal, and stores it. The electronic device 1 refers to the most recent transition of the calculated amplitude difference and the history of increase and decrease of the drive frequency fdr.

[0103] The electronic device 1 determines whether the amplitude acquired this time is increased with respect to the amplitude acquired last time by the driving circuit 10A. When the electronic device 1 determines that the determination is a positive determination by the driving circuit 10A, the electronic device 1 increases the driving frequency fdr in the same way as when the driving frequency fdr was increased last time, and decreases the driving frequency fdr in the same way as when the driving frequency fdr was decreased last time. On the other hand, when the electronic device 1 determines that the determination is a negative determination by the driving circuit 10A, the electronic device 1 decreases the driving frequency fdr in the case where the driving frequency fdr was increased last time, and increases the driving frequency fdr in the case where the driving frequency fdr was decreased last time. Note that the electronic device 1 may increase or decrease the driving frequency fdr by a predetermined value in order to check the transition of the amplitude of the potential difference between both ends of the vibration device 20 immediately after starting a phase in which the electronic device 1 accepts an operation by an operator or a command from another electronic device.

[0104] According to this configuration, the electronic device 1 determines the drive frequency fdr to approach the vibration frequency fres even during the phase in which the electronic device 1 is being operated by an operator, so that the vibration device 20 can be driven with high efficiency even while being operated by the operator.

[0105] Furthermore, the electronic device 1 equipped with the drive circuit 10A according to the first embodiment increases or decreases the drive frequency fdr so as to approach the vibration frequency fres in the phase in which the electronic device 1 receives an operation by an operator or a command from another electronic device after performing a calibration process of the drive frequency fdr at the timing of startup or the timing of release from sleep mode, but the same process may be performed even when the drive circuit 10B according to the second embodiment is installed. Note that the electronic device 1 equipped with the drive circuit 10B performs the same process as the electronic device 1 equipped with the drive circuit 10A, except for the control of short-circuiting and opening of the short-circuit control elements SW1 and SW2, and therefore a description thereof will be omitted.

[0106] According to this configuration, the electronic device 1 determines the drive frequency fdr to approach the vibration frequency fres even during the phase in which the electronic device 1 is being operated by an operator, so that the vibration device 20 can be driven with high efficiency even while being operated by the operator. [Explanation of symbols]

[0107] 1...electronic device, 10A...driving circuit, 10B...driving circuit, 11...signal generating section, 12A...detecting section, 12B...detecting section, 13A...control section, 13B...control section, 20...vibration device

Claims

1. A drive circuit for driving a vibration device that vibrates in response to a drive signal, a signal generating unit that generates the drive signal to have a drive frequency and transmits the generated drive signal to the vibration device; a detection unit that detects vibration information related to vibration of the vibration device from the vibration device; a control unit that determines the drive frequency based on the vibration information detected by the detection unit and transmits the determined drive frequency to the signal generation unit; A drive circuit comprising:

2. The vibration information is a vibration frequency at which the vibration device vibrates.

2. The drive circuit of claim 1.

3. The control unit determines the drive frequency so that the drive frequency approaches the vibration frequency.

3. The drive circuit according to claim 2.

4. the detection unit detects the vibration information from the vibration device after the signal generation unit stops transmitting the drive signal to the vibration device. The drive circuit according to any one of claims 1 to 3.

5. The vibration information is a phase difference between a vibration signal generated by vibration of the vibration device and the drive signal.

2. The drive circuit of claim 1.

6. The control unit determines the drive frequency so that the phase difference approaches a predetermined value.

6. The drive circuit according to claim 5.

7. The vibration information is an amplitude of a vibration signal generated by vibration of the vibration device.

2. The drive circuit according to claim 1.

8. The control unit determines the drive frequency so that the amplitude increases.

8. The drive circuit according to claim 7.

9. a vibration device that vibrates in response to a drive signal; a drive circuit including a signal generating unit that generates the drive signal to have a drive frequency and transmits the generated drive signal to the vibration device, a detection unit that detects vibration information related to the vibration of the vibration device from the vibration device, and a control unit that determines the drive frequency based on the vibration information detected by the detection unit and transmits the determined drive frequency to the signal generating unit; An electronic device comprising:

10. Functions as an electronic pen 10. The electronic device according to claim 9.

11. A method for driving a vibration device that vibrates in response to a drive signal, comprising: generating the drive signal to have a drive frequency; transmitting the generated drive signal to the vibration device; detecting vibration information from the vibration device relating to vibration of the vibration device; determining the drive frequency based on the detected vibration information; A method for driving a vibration device comprising:

Images