JP2010170483A - Contact rendering device and driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact rendering device capable of expanding displacement and achieving dramatic reduction in size/weight even while using a PZT element, and a driving method therefor. <P>SOLUTION: The contact rendering device 10 includes: piezoelectric elements 12 disposed aligned on a base plate 11; pins 13 placed so as to be moved in a direction that the piezoelectric elements 12 expand or contract; a top cover 15 that covers an entire positioning cover 14 and has a key top formed in a curved manner to fit the shape of a finger; and coil springs 16 for forcing the pins 13 to the piezoelectric element 12 side. At the time of contact rendering, a driving circuit 5 applies a driving frequency of 1 kHz (preferably several kHz) or more to the target piezoelectric elements 12 to displace the piezoelectric elements 12 at a high speed. By the collision of the piezoelectric elements 12 and the pins 13, the piezoelectric elements 12 are struck up and the pins 13 gain a large amount of displacement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a contact presentation device and a driving method for transmitting various information using force sensation.

  There is an actuator that utilizes the displacement of an element by a PZT element. However, a PZT bulk element has a small displacement amount of about 1 μm when a rated voltage is applied at, for example, 0.9 mm × 0.9 mm × 1.6 mm. Since the displacement amount of the PZT element itself is small, there are many examples of using a PZT element having a bimorph structure that expands the displacement. The bimorph structure is a structure in which a conductive plate is integrated between upper and lower piezoelectric plates, and either the piezoelectric plate or the conductive plate is a common electrode and the other is a segment electrode.

  In Patent Document 1, a piezoelectric element piece in which a piezoelectric layer made of a piezoelectric material is laminated on both plate surfaces of a thin piece made of an elastic conductive material, and a base end part of the thin piece located at the base end part of the piezoelectric element piece are fixed. A piezoelectric actuator having a bimorph structure including fixing means and supporting means for supporting a substantially central portion of a piezoelectric element piece with a degree of freedom of bending displacement is described.

  Patent Document 2 describes a tactile stimulation device that moves a pin up and down using a PZT element having a bimorph structure. This tactile stimulation device performs frequency decomposition on acoustic information such as voice, vibrates the vibration pins independently, and continuously gives an accurate vibration pattern to the fingertip.

Japanese Patent Publication No. 3-32236 JP 2000-166962 A

  However, in such an actuator using a conventional PZT element having a bimorph structure, it is difficult to reduce the size and weight of the device because the distance in the longitudinal direction of the mechanism portion is required to increase the displacement. Met. Since the tactile stimulation device described in Patent Document 2 is configured to increase the positional change in the height direction of the pin using the length of the arm in the longitudinal direction of the bimorph structure, it is structurally small (that is, the arm is shortened). ) If this happens, sufficient pin displacement cannot be obtained and stimulation cannot be transmitted to the fingertip.

  In any case, when using a PZT element with a small amount of displacement originally, a bimorph structure must be adopted, and in addition to the actuator itself using this bimorph structure PZT element having a considerable size and weight, driving The voltage is high, and it was impossible to install in a mobile phone, for example.

  The present invention has been made in view of the above points, and provides a contact presentation device and a driving method capable of enlarging displacement while using a PZT element, and capable of significantly reducing size and weight. The purpose is to do.

  The contact presentation device of the present invention includes a piezoelectric element disposed on a base substrate, a movable member that comes into contact with the piezoelectric element so as to be separable, a regulating member that regulates the movement of the movable member, and the piezoelectric element And a driving unit that applies a driving frequency equal to or higher than a predetermined frequency to displace the piezoelectric element at high speed.

  The driving method of the present invention includes a step of bringing a movable member into contact with an expansion / contraction direction of a piezoelectric element, a step of applying a driving frequency equal to or higher than a predetermined frequency to the piezoelectric element to displace the piezoelectric element at a high speed, and the piezoelectric element And the step of jumping the movable member from the piezoelectric element based on the equation of motion derived from the displacement of the movable member and the mass of the movable member.

  ADVANTAGE OF THE INVENTION According to this invention, a displacement can be expanded using a PZT element, and reduction in size and weight can be achieved markedly.

Diagram for explaining the basic principle of the present invention The figure which shows the whole structure of the contact presentation apparatus which concerns on embodiment of this invention. The perspective view which shows the structure of the contact presentation apparatus which concerns on the said embodiment. The perspective view which shows the structure of the base plate and piezoelectric element of the contact presentation apparatus which concerns on the said embodiment. The perspective view which shows the structure of the base plate and positioning cover of the contact presentation apparatus which concerns on the said embodiment. The perspective view which shows the structure of the pin mounted on the piezoelectric element of the contact presentation apparatus which concerns on the said embodiment. The perspective view which shows the assembly process of the baseplate of the contact presentation apparatus which concerns on the said embodiment, a pin, and a positioning cover. Sectional drawing of the contact presentation apparatus which concerns on the said embodiment Sectional drawing when the finger of the contact presentation device according to the embodiment is placed on the top cover The figure which measured the displacement amount of the pin at the time of changing the drive frequency applied to the piezoelectric element of the contact presentation apparatus based on the said embodiment

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Principle explanation)
FIG. 1 is a diagram for explaining the basic principle of the present invention. FIG. 1 (a) is a diagram showing the frequency response of the PZT element, FIG. 1 (b) is its configuration diagram, and FIG. These are the figures which show the setting conditions in a table | surface.

  The PZT element is displaced in response to the frequency by changing the frequency of the drive signal. Note that a normal actuator (for example, a motor or a solenoid) has an inductance component, and thus has a second-order lag system in which the response cannot be maintained when the frequency is increased.

  As shown in FIG. 1A, since the PZT element is displaced by crystal distortion, the responsiveness is maintained even if the frequency is maintained.

  The present inventors have found a method of expanding displacement (or moving speed, acceleration) in a short time using a PZT bulk element.

  As shown in FIG. 1B, a movable pin 2 is placed on the PZT bulk element 1, and a voltage is applied to the PZT bulk element 1 to displace it. The present inventors have found that when the mass of the pin 2 and the frequency of the voltage applied to the PZT bulk element 1 satisfy a predetermined relationship, the displacement amount of the pin 2 increases extremely. The displacement amount of the pin 2 is due to the pin 2 jumping from the upper part of the PZT bulk element 1. At a low frequency, the pin 2 moves following the displacement of the PZT bulk element 1, but when the frequency becomes higher than around 1 kHz, the movement according to the mass of the pin 2 is started. This is because, when the PZT bulk element 1 is displaced at a high speed when the pin 2 falls and comes into contact with the PZT bulk element 1, the PZT bulk element 1 and the pin 2 collide, and a larger force is applied to the pin 2. In addition, the amount of displacement of the pin 2 is increased by jumping up the pin 2.

  The amount of displacement of the pin 2 varies depending on the material and shape of the pin 2, the restoring force of the pin 2 toward the PZT bulk element 1, the shape, size, and applied voltage of the PZT bulk element 1. According to the experiments by the present inventors, it has been found that the setting of the mass of the pin 2 and the frequency of the voltage applied to the PZT bulk element 1 is dominant. Of these, the pin 2 has a certain range of size and shape for use, and if a highly rigid metal is used, the adjustment range for mass is small. For this reason, the setting of the frequency of the voltage applied to the PZT bulk element 1 is important.

  Hereinafter, the derivation of the equation of motion representing the time of pin jumping will be described.

  FIG. 1C shows units of the mass m, the speed v1, the acceleration α, the jump height h, the collision time t, the speed v2, the acceleration β of the PZT bulk element 1, and the driving frequency f. In the following description, for simplicity, the pin 2 is abbreviated as a pin, and the PZT bulk element 1 is abbreviated as PZT.

  When the force with which the pin and PZT collide is the largest, the pin jumps to the maximum. Here, when it is considered that the pin / PZT is a rigid body, the impact force F (N) caused by the contact between the pin and the PZT can be expressed by the following equation (1).

F = m · a
= M · (α + β)
= M · (v1 + v2) / t (1)
If the pin mass m and the collision time t are constant, it is necessary to increase the speed of the pin and the PZT immediately before the collision in order to increase the impact force.

  The pin speed v1 depends on the jumped height and is expressed by the following equation (2). g is a gravitational acceleration.

v1 = (2 · g · h) ^(1/2) (2)
Actually, since the pin is regulated by the stopper, the height is limited.

  The displacement speed of PZT does not change unless the applied voltage is changed. However, the number of expansions / contractions can be changed by the drive frequency f. For example, the time T (s) during which the pin falls with Max raised to Max is expressed by the following equation (3).

T = (h · 2 / g) ^(1/2) (3)
PZT expands and contracts once in 1 / f seconds according to the driving frequency f. By setting the frequency according to the timing of collision, it is possible to perform adjustment so that the pin collides with the v2 being the largest.

  It should be noted that the above is a simple model ignoring friction and the like, and since each restriction is provided, it is not strictly applicable.

(Embodiment)
FIG. 2 is a diagram showing an overall configuration of a contact presentation device according to an embodiment of the present invention based on the above basic concept. The present embodiment is an example applied to a tactile presentation device that transmits various types of information to a finger.

  As shown in FIG. 2, the contact presentation device 10 is driven by the output of the drive circuit 5.

  The drive circuit 5 sets the drive signal to the rated voltage of the PZT bulk element and applies a drive frequency higher than the vicinity of 1 kHz.

  FIG. 3 is a perspective view showing the configuration of the contact presentation device 10, FIG. 3 (a) is a broken perspective view thereof, and FIG. 3 (b) is a sectional view thereof.

  As shown in FIG. 3, the contact presentation device 10 includes a base plate 11, a piezoelectric element 12 arranged in alignment on the base plate 11, a pin 13 placed so as to be separable in the expansion / contraction direction of the piezoelectric element 12, A positioning cover 14 that covers the entire aligned piezoelectric elements 12 and regulates the position of the pin 13, a key top that is formed in a curved shape in accordance with the shape of the finger and covers the entire positioning cover 14, and an opening hole that opens in the key top The top cover 15 which has 15a and the pin 13 which bounces up protrudes from the opening hole 15a, and the coil spring 16 which urges the pin 13 to the piezoelectric element 12 side are comprised.

  4 is a perspective view showing configurations of the base plate 11 and the piezoelectric element 12, FIG. 5 is a perspective view showing configurations of the base plate 11 and the positioning cover 14, and FIG. 6 is placed on the piezoelectric element 12. As shown in FIG. FIG. 7 is a perspective view showing an assembly process of the base plate 11, the pin 13 and the positioning cover 14.

  As shown in FIGS. 3 and 4, the base plate 11 includes a base plate main body 11a, a groove portion 11b provided on the surface of the base plate main body 11a, a claw portion 11c for fixing the positioning cover 14, and a leg portion 11d having a screwing hole. Is done. Three piezoelectric elements 12 are arranged in alignment in one groove 11b, and one end of the piezoelectric element 12 is fixed to the groove 11b. In the present embodiment, nine piezoelectric elements 12 are aligned, but any number or arrangement may be used. For example, a configuration in which 16 piezoelectric elements 12 are aligned with the base plate body 11a may be employed.

  The piezoelectric element 12 is, for example, a PZT bulk element.

  As shown in FIGS. 3 and 6, the pin 13 is placed in contact with the end 12 a of the piezoelectric element 12. The pin 13 includes a base portion 13 a that slides in the opening hole 14 a of the positioning cover 14, a flange portion 13 b that regulates the coil spring 16, and a head portion 13 c. The pin 13 is lightly abutted against the end 12 a of the piezoelectric element 12 by its own weight or the bias of the coil spring 16. The pin 13 can be flipped up by the displacement of the piezoelectric element 12. Further, as shown in FIG. 3B, the length of each pin 13 is determined according to the shape of the top cover 15.

  As shown in FIGS. 3 and 5, the positioning cover 14 has an opening 14 a, and the base 13 a of the pin 13 is slidably received in the opening 14 a and placed on the piezoelectric element 12. The position of the pin 13 is regulated.

  As shown in FIGS. 3 and 7, the positioning cover 14 is fixed on the base plate body 11a by the claw portions 11c while the pins 13 are placed on the piezoelectric elements 12 so as to maintain the state of FIG.

  As shown in FIG. 3, the key top of the top cover 15 is formed in a curved shape that matches the shape of the finger. The top cover 15 has an opening hole 15a, and the head 13c of the pin 13 is slidably accommodated in the opening hole 15a. The pin 13 protrudes from the surface of the top cover 15 when the head 13 bounces. The top cover 15 is fixed to the side surface of the base plate main body 11a so as to cover the pins 13 and the positioning cover 14 in the state of FIG.

  As shown in FIG. 3B, the coil spring 16 is inserted between the flange portion 13b of the pin 13 and the upper surface inside the top cover 15 in the state shown in FIG. 6, and lightly biases the pin 13 toward the piezoelectric element 12 side. Accordingly, the end of the base portion 13a of the pin 13 can be brought into contact with the end portion 12a of the piezoelectric element 12 even when the contact presentation device 10 is not used in a horizontal state. When the contact presentation device 10 is determined to be used in a horizontal state, the pin 13 may be returned to the piezoelectric element 12 side by using the weight of the pin 13. In this case, the coil spring 16 is not necessary, the process of attaching the coil spring 16 can be reduced, and the cost can be reduced.

  Hereinafter, the operation of the contact presentation device 10 configured as described above will be described. First, a method for assembling the contact presentation device 10 will be described.

  As shown in FIG. 4, the piezoelectric elements 12 are arranged in a lattice pattern on the base plate body 11a. The number and arrangement interval of the piezoelectric elements 12 are arbitrary. Setting the arrangement interval of the piezoelectric elements 12 to about 2-4 mm is effective in transmitting a sense to the fingertip.

  As shown in FIG. 5, a positioning cover 14 is installed so as to cover the piezoelectric elements 12 arranged in a lattice shape, and as shown in FIG. 7, the base portion 13 a of the pin 13 is accommodated in the opening hole 14 a of the positioning cover 14. To do. Thereby, as shown in FIG. 6, the base portion 13 a of the pin 13 comes into contact with the end portion 12 a of the piezoelectric element 12.

  A coil spring 16 is attached to the pin 13 to urge the pin 13 so as to contact the piezoelectric element 12.

  As shown in FIG. 3, the top cover 15 is fixed to the side surface of the base plate main body 11a so as to cover the pins 13 and the positioning cover 14 in the state of FIG.

  Next, the operation of the contact presentation device 10 will be described.

  FIG. 8 is a cross-sectional view of the contact presentation device 10, FIG. 8 (a) is a cross-sectional view before the pin jumps up (before Jump), and FIG. 8 (b) is after the pin jumps up (after Jump). It is sectional drawing.

  As shown in FIG. 8, the key top of the top cover 15 is formed in a curved shape that matches the shape of the finger. As shown in FIG. 8A, in the initial state, the top cover 15 is in a state in which the head 13c of the pin 13 is retracted from the surface of the top cover 15 so that the fingertip does not feel. This surface dent amount is, for example, 0.1 mm.

  A drive signal having a predetermined rated voltage and the above-described drive frequency is applied to the piezoelectric element 12 at a position where a sense is to be transmitted, and the corresponding piezoelectric element 12 is vibrated. Specifically, the piezoelectric element 12 of the contact presentation device 10 is driven by the output of the drive circuit 5 shown in FIG. The driving signal supplied to the piezoelectric element 12 may be any waveform (for example, a rectangular wave, a sine wave, a triangular wave, or a sawtooth wave) as long as the signal satisfies a predetermined rated voltage and driving frequency.

  As shown in FIG. 8B, when the corresponding piezoelectric element 12 vibrates, the pin 13 contacting the corresponding piezoelectric element 12 jumps up according to the reason described in the explanation of the principle. In the case of FIG. 8B, all the three pins 13 jump and the head 13 c of the pin 13 protrudes from the surface of the top cover 15. The surface protrusion amount is, for example, 0.5 mm.

  When the head 13c of the pin 13 strikes the finger placed on the top cover 15 vigorously, the user can obtain contact presentation information from the fingertip. For example, in a 3 × 3 matrix arrangement of pins 13, if the left three rows of pins 13 jump up and the user perceives this from a finger, the function assigned to “left” is presented. Can be recognized.

  FIG. 9 is a cross-sectional view of the contact presentation device 10 when a finger is placed on the top cover.

  As shown in FIG. 9, the key top of the top cover 15 is formed in a curve that matches the shape of the finger 20. Further, the length of the pin 13 is adjusted in accordance with the shape of the curved top cover 15 that is a finger contact portion. Thereby, when each pin 13 jumps up and the head 13c of the pin 13 protrudes from the surface of the top cover 15, the touch can be made uniform.

  Moreover, since the user only puts his / her finger on the curved top cover 15 instead of pressing the finger against the key top of the top cover 15, the user can use it with a natural feeling. For this reason, it can be used as a man-machine interface with an excellent user-friendly sense of use. Since the feel of the finger placed on the curved top cover 15 is natural and uncomfortable, the user can sufficiently obtain a feel from the finger even when the surface protrusion amount is 0.5 mm, for example. As in the conventional example, when the finger is pressed against the key top, the tactile sensation changes depending on the user's force, and the balance between the pressing force and the pressing force is different for each individual. An excellent contact presentation like form cannot be obtained.

  FIG. 10 is a diagram in which the amount of displacement of the pin 13 is measured when the drive frequency applied to the piezoelectric element 12 is changed. FIGS. 10A to 10E show measured waveforms in which the drive frequencies are set to 10 Hz, 100 Hz, 500 Hz, 1 kHz, and 5 kHz in this order. In each figure, the upper waveform indicates the drive signal, and the lower waveform indicates the pin displacement signal. The pin displacement uses a laser length measuring machine, and the measurement range is all the same at 50 μm / v.

  As shown in FIG. 10D, when the drive frequency is 1 kHz, the displacement amount of the pin 13 increases. As shown in FIG. 10E, when the driving frequency is set to several kHz, the displacement amount of the pin 13 increases.

  As described above in detail, the contact presentation device 10 according to the present embodiment includes the piezoelectric element 12 arranged in alignment on the base plate 11 and the pin 13 placed so as to be separable in the expansion / contraction direction of the piezoelectric element 12. A top cover 15 that covers the entire positioning cover 14 and has a key top that is curved to match the shape of the finger, and a coil spring 16 that biases the pin 13 toward the piezoelectric element 12. At the time of contact presentation, a drive frequency of 1 kHz (preferably several kHz) or more is applied to the target piezoelectric element 12 to displace the corresponding piezoelectric element 12 at a high speed. When the piezoelectric element 12 and the pin 13 collide, the piezoelectric element 12 is flipped up and the pin 13 can acquire a large displacement. Since the pin 13 that has been flipped up protrudes from the opening hole 15a of the top cover 15, the user can receive the stimulus of the pin 13 that has been flipped up vigorously and obtain contact presentation information.

  In the present embodiment, the displacement can be enlarged while using the PZT element, and the size and weight can be significantly reduced as compared with the bimorph actuator. A device to which this embodiment is applied is unparalleled in terms of miniaturization and weight reduction, and the way to install it in various portable devices such as cellular phones can be opened. Further, in the present embodiment, in addition to the effect of reducing the size and weight, the number of parts can be reduced, and the number of assembling steps and costs can be reduced.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, Various changes are possible based on the technical idea of this invention, and this invention covers these. It is natural.

  In each of the above-described embodiments, the name “contact presentation device” is used. However, this is for convenience of explanation, and of course, an actuator, a finger direction transmission device, or the like may be used.

  INDUSTRIAL APPLICABILITY The contact presentation device and the driving method according to the present invention are useful for a tactile presentation device that transmits various types of information to a contact presentation target site such as a finger.

DESCRIPTION OF SYMBOLS 1 PZT bulk element 2,13 pin 5 Drive circuit 10 Contact presentation apparatus 11 Base plate 12 Piezoelectric element 14 Positioning cover 14a, 15a Opening hole 15 Top cover 16 Coil spring

Claims (9)

A piezoelectric element disposed on the base substrate;
A movable member that comes into contact with the piezoelectric element so as to be separable in the expansion and contraction direction;
A regulating member that regulates the movement of the movable member;
A driving unit that applies a driving frequency equal to or higher than a predetermined frequency to the piezoelectric element to displace the piezoelectric element at a high speed;
A contact presentation device comprising:   The contact presentation apparatus according to claim 1, wherein the movable member abuts on the piezoelectric element by its own weight in an initial state in which contact presentation is not performed.   The contact presentation device according to claim 1, further comprising a spring that urges the movable member to abut on the piezoelectric element.   The contact presenting device according to claim 1, wherein the driving unit applies the driving frequency that flips up the movable member in contact with the piezoelectric element.   The contact presentation device according to claim 1, wherein the driving unit applies a driving frequency of 1 kHz or more to the piezoelectric element during contact presentation. A placement unit for placing the contact presentation target part;
The contact presentation device according to claim 1, wherein the movable member is accommodated in the placement unit in an initial state in which contact presentation is not performed, and protrudes from the placement unit surface during contact presentation. The contact presentation target part is a finger,
The placement portion has a curved portion that matches the shape of the finger,
The contact presenting apparatus according to claim 1, wherein the movable member has a total length that matches the curved portion. A plurality of the piezoelectric elements are disposed on the base substrate,
The contact presentation device according to claim 1, wherein the driving unit individually drives a plurality of the piezoelectric elements arranged. Contacting the movable member in the expansion and contraction direction of the piezoelectric element;
Applying a driving frequency equal to or higher than a predetermined frequency to the piezoelectric element to displace the piezoelectric element at a high speed;
And a step of jumping the movable member from the piezoelectric element based on an equation of motion derived from the displacement of the piezoelectric element and the mass of the movable member.

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