num="0050">In addition, in a case where the electronic apparatus 1 functions as a pen for VR, when the operator indicates a position on an imaginary plane positioned in a space by the electronic apparatus 1, the electronic apparatus 1 drives the driving circuit 10A so as to change the degree of vibration of the vibration device 20 according to a moving speed or a moving acceleration with respect to the imaginary plane. Thus, though the electronic apparatus 1 is a pen for VR, the electronic apparatus 1 can reproduce a writing feel and a drawing feel as an analog pen.

Flow of Series of Operations

The driving circuit 10A according to the first embodiment, each constituent element of the electronic apparatus 1 and the vibration device 20 have been described above. Next, a flow of a series of operations of the driving circuit 10A according to the first embodiment will be described. FIG. 2 is a flowchart illustrating the flow of the series of operations of the driving circuit 10A in the first example.

SP10

The driving circuit 10A uses the control circuit 13A to control both terminals of the short circuit control element SW1 and both terminals of the short circuit control element SW2 to a short-circuited state. Then, the processing proceeds to the processing of SP12.

SP12

The driving circuit 10A uses the control circuit 13A to make the signal generation circuit 11 generate the driving signal dr and apply the generated driving signal dr to the vibration device 20 via the output circuit 14A for a predetermined period of time or more. Incidentally, the signal generation circuit 11 generates the driving signal dr so as to have the driving frequency fdr that is determined by the control circuit 13A or is an initial value determined in advance. Then, the processing proceeds to the processing of SP14.

SP14

The driving circuit 10A uses the control circuit t 13A to make the generation and application of the driving signal dr by the signal generation circuit 11 stopped. Next, the driving circuit 10A uses the control circuit 13A to control both terminals of the short circuit control element SW1 and both terminals of the short circuit control element SW2 to an opened state. Then, the processing proceeds to the processing of SP16.

SP16

The driving circuit 10A uses the control circuit 13A to make the detection circuit 12A obtain temporal changes in the potential difference across the vibration device 20 as a vibration signal, and detect the frequency of the obtained vibration signal as the vibration frequency fres of the vibration device 20. Then, the processing proceeds to the processing of SP18.

SP18

The driving circuit 10A uses the control circuit 13A to calculate a difference between the driving frequency fdr and the vibration frequency fres, and determine whether or not the calculated difference is within a predetermined range. The predetermined range, for example, may be a range between an upper limit value and a lower limit value determined in advance for the calculated difference, or may be a range of an upper limit value and a lower limit value determined in advance for a ratio of the calculated difference to the driving frequency fdr (for example, ±1% of the driving frequency fdr). Then, when the determination is a negative determination, the driving circuit 10A determines that the driving frequency fdr is inappropriate for the vibration device 20, and the processing proceeds to the processing of SP20. When the determination is a positive determination, on the other hand, the driving circuit 10A determines that the driving frequency fdr is appropriate for the vibration device 20, and the series of processing illustrated in FIG. 2 is ended.

SP20

The driving circuit 10A uses the control circuit 13A to determine whether or not the driving frequency fdr is lower than the vibration frequency fres. Then, when the determination is a positive determination, the processing proceeds to the processing of SP22. When the determination is a negative determination, on the other hand, the processing proceeds to the processing of SP24.

SP22

The driving circuit 10A uses the control circuit 13A to increase the driving frequency fdr from a present value. When the control circuit 13A increases the driving frequency fdr, the control circuit 13A may increase the driving frequency fdr by a predetermined value, may increase the driving frequency fdr by a predetermined ratio, or may increase the driving frequency fdr such that the driving frequency fdr becomes the same value as the value of the vibration frequency fres. Then, the processing returns to the processing of SP10.

SP24

The driving circuit 10A uses the control circuit 13A to decrease the driving frequency fdr from the present value. When the control circuit 13A decreases the driving frequency fdr, the control circuit 13A may decrease the driving frequency fdr by a predetermined value, may decrease the driving frequency fdr by a predetermined ratio, or may decrease the driving frequency fdr such that the driving frequency fdr becomes the same value as the value of the vibration frequency fres. Then, the processing returns to the processing of SP10.

Effects

As described above, in the first embodiment, the driving circuit 10A is the driving circuit 10A for driving the vibration device 20 that vibrates according to the driving signal dr, the driving circuit 10A including the signal generation circuit 11 that generates the driving signal dr so as to have the driving frequency fdr, and transmits the generated driving signal dr to the vibration device 20, the detection circuit 12A that detects the vibration information related to the vibration of the vibration device 20 from the vibration device 20, and the control circuit 13A that determines the driving frequency fdr on the basis of the vibration information detected by the detection circuit 12A, and transmits the determined driving frequency fdr to the signal generation circuit 11.

According to this configuration, the driving circuit 10A determines the driving frequency fdr on the basis of the vibration information of the vibration device 20. The driving circuit 10A can therefore drive the vibration device 20 with high efficiency.

In addition, in the first embodiment, the vibration information is the vibration frequency fres at which the vibration device 20 vibrates.

According to this configuration, the driving circuit 10A determines the driving frequency fdr on the basis of the vibration frequency fres of the vibration device 20. The driving circuit 10A can therefore drive the vibration device 20 with high efficiency.

In addition, in the first embodiment, the control circuit 13A determines the driving frequency fdr such that the driving frequency fdr approaches the vibration frequency fres.

According to this configuration, the driving circuit 10A brings the driving frequency fdr close to the vibration frequency fres of the vibration device 20. The driving circuit 10A can therefore drive the vibration device 20 with high efficiency.

In addition, in the first embodiment, the vibration information is the amplitude of the vibration signal generated according to the vibration of the vibration device 20.

According to this configuration, the driving circuit 10A determines the driving frequency fdr on the basis of the amplitude of the vibration signal. The driving circuit 10A can therefore drive the vibration device 20 with high efficiency.

In addition, in the first embodiment, the control circuit 13A determines the driving frequency fdr so as to increase the amplitude of the vibration signal.

According to this configuration, the driving circuit 10A determines the driving frequency fdr so as to increase the amplitude of the vibration signal. The driving circuit 10A can therefore drive the vibration device 20 with high efficiency.

In addition, in the first embodiment, the electronic apparatus 1 includes the vibration device 20 that vibrates according to the driving signal dr, and the driving circuit 10A including the signal generation circuit 11 that generates the driving signal dr so as to have the driving frequency fdr, and transmits the generated driving signal dr to the vibration device 20, the detection circuit 12A that detects the vibration information related to the vibration of the vibration device 20 from the vibration device 20, and the control circuit 13A that determines the driving frequency fdr on the basis of the vibration information detected by the detection circuit 12A, and transmits the determined driving frequency fdr to the signal generation circuit 11.

According to this configuration, the electronic apparatus 1 determines the driving frequency fdr on the basis of the vibration information of the vibration device 20. The electronic apparatus 1 can therefore drive the vibration device 20 with high efficiency.

In addition, in the first embodiment, the electronic apparatus 1 functions as an electronic pen.

According to this configuration, the electronic apparatus 1 determines the driving frequency fdr on the basis of the vibration information at a time of usage of the electronic pen including the vibration device 20. The electronic apparatus 1 can therefore drive the vibration device 20 of the electronic pen with high efficiency.

In addition, in the first embodiment, a driving method for the vibration device 20 is a driving method for driving the vibration device 20 that vibrates according to the driving signal dr, the driving method including generating the driving signal dr so as to have the driving frequency fdr, transmitting the generated driving signal dr to the vibration device 20, detecting the vibration information related to the vibration of the vibration device 20 from the vibration device 20, and determining the driving frequency fdr on the basis of the detected vibration information.

According to this method, the driving method for the vibration device 20 determines the driving frequency fdr on the basis of the vibration information of the vibration device 20. The driving method can therefore drive the vibration device 20 with high efficiency.

Second Embodiment

A second embodiment will next be described.

Configuration

FIG. 3 is a diagram illustrating a second example of the driving circuit. A driving circuit 10B is, for example, formed by providing the driving circuit 10A with an output circuit 14B in place of to the output circuit 14A, providing the driving circuit 10A with a detection circuit 12B in place of the detection circuit 12A, and providing the driving circuit 10A with a control circuit 13B in place of the control circuit 13A. Incidentally, the signal generation circuit 11 is similar to that of the first embodiment except that the signal generation circuit 11 transmits the generated driving signal dr to not only the output circuit 14A but also the detection circuit 12B, and therefore description thereof will be omitted.

The vibration device 20 is similar to that of the first embodiment. The vibration device 20 vibrates under driving control of the driving circuit 10A. When a driving signal dr as a signal enhanced via the output circuit 14B is applied across the vibration device 20, the vibration device 20 vibrates according to the application. In addition, the vibration device 20 has one terminal connected to the drain terminals of the transistors TR1 and TR2 of the output circuit 14B, and has another terminal connected to the drain terminals of the transistors TR3 and TR4 of the output circuit 14B and an input terminal of the detection circuit 12B.

The output circuit 14B is formed by removing 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 a signal output from the logical negation circuit INV1, and outputs the signal resulting from the operation to the one terminal of the vibration device 20. In addition, the logical negation circuit INV3 in the output circuit 14B performs a logical negation operation on the driving signal dr transmitted from the signal generation circuit 11, and outputs the signal resulting from the operation to the other terminal of the vibration device 20.

The detection circuit 12B detects vibration information related to the vibration of the vibration device 20 from the vibration device 20. Specifically, the detection circuit 12B starts to detect the vibration information of the vibration device 20 on the basis of the driving signal dr having been transmitted from the signal generation circuit 11 to the output circuit 14B and the detection circuit 12B. Here, the detection circuit 12B detects, as the vibration information, a phase difference θ between the driving signal dr and the vibration signal as temporal changes in the potential of the other terminal of the vibration device 20, the amplitude of the vibration signal, and the like. In addition, the detection circuit 12B outputs a detection signal res including the detected vibration information to the control circuit 13B.

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

The control circuit 13A determines a driving frequency fdr on the basis of the vibration information such as the phase difference θ and the amplitude detected by the detection circuit 12B, and transmits the determined driving frequency fdr to the signal generation circuit 11. Specifically, the control circuit 13B determines the driving frequency fdr such that the absolute value of the phase difference θ approaches a value of π/2, for example. In addition, the control circuit 13B determines the driving frequency fdr so as to increase the amplitude indicated by the vibration information. In addition, the control circuit 13B controls the transmission of the driving signal dr and the stopping of the transmission by the signal generation circuit 11 and the detection of the vibration information from the vibration device 20 and the stopping of the detection by the detection circuit 12B.

Referring to FIG. 4A and FIG. 4B, description will be made of relations of a ratio between the driving frequency fdr and the vibration frequency fres to the phase difference θ and an amplitude magnification factor when the vibration device 20 is vibrated. FIG. 4A is a graph illustrating the relation of the ratio between the driving frequency fdr and the vibration frequency fres to the phase difference θ when the vibration device 20 is vibrated. In addition, FIG. 4B is a graph illustrating the relation of the ratio between the driving frequency fdr and the vibration frequency fres to the amplitude magnification factor when the vibration device 20 is vibrated.

As illustrated in FIG. 4A, the ratio of the driving frequency fdr to the vibration frequency fres is 1.0 when the phase difference θ is the value of π/2 in each of cases where a damping ratio of the vibration of the vibration device 20 is 0, 0.2, 0.5, and 1.0. That is, the driving frequency fdr is substantially equal to the vibration frequency fres when the phase difference θ is the value of π/2.

In addition, as illustrated in FIG. 4B, the amplitude magnification factor increases as the ratio of the driving frequency fdr to the vibration frequency fres approaches 1.0 in each of cases where the damping ratio of the vibration of the vibration device 20 is 0, 0.2, 0.5, and 1.0. Incidentally, the amplitude magnification factor is substantially at a maximum when the driving frequency fdr is slightly higher than the vibration frequency fres.

Flow of Series of Operations

Each constituent element of the driving 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 driving circuit 10B according to the second embodiment will be described. FIG. 5 is a flowchart illustrating the flow of the series of operations of the driving circuit 10B in the second example.

SP50

The driving circuit 10B uses the control circuit 13B to make the signal generation circuit 11 generate the driving signal dr and apply the generated driving signal dr to the vibration device 20 via the output circuit 14B for a predetermined period of time or more. Incidentally, the signal generation circuit 11 generates the driving signal dr so as to have the driving frequency fdr that is determined by the control circuit 13B or is an initial value determined in advance. Then, the processing proceeds to the processing of SP52.

SP52

The driving circuit 10B uses the control circuit 13B to make the detection circuit 12B obtain temporal changes in the potential of the other terminal of the vibration device 20 as a vibration signal, and detect the phase difference θ between the obtained vibration signal and the driving signal dr. Then, the processing proceeds to the processing of SP54.

SP54

The driving circuit 10B uses the control circuit 13B to determine whether or not the phase difference θ is within a predetermined range. The predetermined range is, for example, a range between an upper limit value and a lower limit value determined in advance with π/2 as a reference. The upper limit value and the lower limit value are π/2±1%, for example. Then, when the determination is a negative determination, the driving circuit 10B determines that the driving frequency fdr is inappropriate for the vibration device 20, and the processing proceeds to the processing of SP56. When the determination is a positive determination, on the other hand, the driving circuit 10B determines that the driving frequency fdr is appropriate for the vibration device 20, and the series of processing illustrated in FIG. 5 is ended.

SP56

The driving circuit 10B uses the control circuit 13B to determine whether or not the phase difference θ is a value larger than 0 but smaller than π/2. Then, when the determination is a positive determination, the processing proceeds to the processing of SP58. When the determination is a negative determination, on the other hand, the processing proceeds to the processing of SP60.

SP58

The driving circuit 10B uses the control circuit 13B to increase the driving frequency fdr from a present value. When the control circuit 13B increases the driving frequency fdr, the control circuit 13B may increase the driving frequency fdr by a predetermined value, or may increase the driving frequency fdr by a predetermined ratio. Then, the processing returns to the processing of SP52.

SP60

The driving circuit 10B uses the control circuit 13B to decrease the driving frequency fdr from the present value. When the control circuit 13B decreases the driving frequency fdr, the control circuit 13B may decrease the driving frequency fdr by a predetermined value, or may decrease the driving frequency fdr by a predetermined ratio. Then, the processing returns to the processing of SP52.

Effects

As described above, in the second embodiment, the vibration information is the phase difference θ between the vibration signal generated according to the vibration of the vibration device 20 and the driving signal dr.

According to this configuration, the driving circuit 10B determines the driving frequency fdr on the basis of the phase difference θ between the vibration signal and the driving signal dr. The driving circuit 10B can therefore drive the vibration device 20 with high efficiency. In addition, the driving frequency fdr can be determined while the driving signal dr remains applied.

In addition, in the second embodiment, the control circuit 13B determines the driving frequency fdr such that the phase difference θ approaches a predetermined value (π/2, for example).

According to this configuration, the driving circuit 10B determines the driving frequency fdr such that the phase difference θ approaches a predetermined value. The driving circuit