JP5143881B2 - Tactile sensation presentation apparatus and control method of tactile sensation presentation apparatus - Google Patents

Description

The present invention relates to a tactile sensation presentation apparatus and a control method for the tactile sensation presentation apparatus .

  In recent years, a mobile terminal such as a mobile phone, an information device such as a calculator and a ticket vending machine, a home appliance such as a microwave oven, a television, and a lighting fixture, an industrial device (FA device), etc. As input devices such as switches, input devices including touch sensors such as touch panels and touch switches are widely used.

  As such a touch sensor, various systems such as a resistive film system, a capacitance system, and an optical system are known. However, any type of touch sensor accepts a touch input by a finger or a stylus pen, and the touch sensor itself is not physically displaced like a push button switch even when touched.

  As described above, even if the touch sensor is touched, the touch sensor itself is not physically displaced, so that the operator cannot obtain feedback for the input even if the touch input is accepted. For this reason, the operator is likely to repeatedly input such as touching the same position many times, and may stress the operator.

  In order to prevent such repeated input, for example, a touch input is received and a sound is produced, or a display color of an input object such as an input button displayed on the display unit corresponding to the input position is displayed. There are known ones in which the input operation can be confirmed by hearing or vision by changing the display mode such as changing.

  However, in the case of a feedback method that works on hearing, it is difficult to confirm in a noisy environment, and if the device used is in a silent state such as manner mode, it cannot be handled. In the feedback method that works visually, if the size of the input object displayed on the display unit is small, especially in the case of finger input, the input object is hidden under the finger and the display mode changes. There are cases where it is not possible.

  Also, a feedback method has been proposed in which when the touch sensor accepts an input regardless of hearing or sight, the touch sensor is vibrated to generate a tactile sensation at the fingertip of the operator (for example, Patent Document 1). 2).

JP 2003-288158 A JP 2008-130055 A

  However, the techniques disclosed in Patent Documents 1 and 2 merely vibrate the touch sensor when the touch sensor receives an input. For this reason, especially when a button switch such as a push button switch (push-type button switch) is drawn on the top of the touch sensor, when the threshold value for accepting input from the touch sensor is low, a finger or the like touches the touch sensor lightly. A tactile sensation is presented just by touching. As a result, an erroneous operation is induced in response to an unintended operation (touch) before the operator pushes, or a sense of incongruity due to an unintended operation (touch) before the operator pushes is given. Here, the threshold value for accepting an input by touch of the touch sensor is a threshold value at which the touch sensor reacts. For example, in the resistive film method, the threshold value is a threshold value of the pressing force with which the upper conductive film contacts the lower conductive film. In the method, it is a detection threshold value of an electrical signal due to contact.

  In order to solve such an inconvenience, the present applicant detects a pressing load due to a touch on the touch surface of the touch sensor, and when the detected load reaches a predetermined threshold value that presents a tactile sensation, Is developing an input device that vibrates and presents a tactile sensation to a pressed object such as a finger.

  According to this input device, when the operator pushes the touch surface and the pressing load reaches a predetermined threshold value, a tactile sensation is presented, so that an erroneous operation due to the unintended touch described above is induced or uncomfortable. It is possible to reliably prevent the operator from recognizing that the input is accepted by the operator as a tactile sensation.

  By the way, in order to configure such an input device, in addition to the basic configuration of the touch sensor and its control unit, a load sensor that detects a pressing load on the touch sensor and an actuator that vibrates the touch sensor are required. For this reason, the number of parts increases and the cost is increased, and it is necessary to secure a space for installing the parts, resulting in an increase in the size of the apparatus.

  Therefore, in order to reduce costs and reduce the size of the apparatus, the present applicant uses the piezoelectric positive effect and the piezoelectric reverse effect of the piezoelectric element to detect the pressure load on the touch surface of the touch sensor. We are developing a device shared as an actuator that vibrates the sensor and touch surface.

  However, according to various experimental studies by the present inventor, it has been found that when the piezoelectric element is shared as a load sensor and an actuator, there are points to be improved as described below. That is, when the touch sensor is continuously pressed like a continuous input (repetitive hitting) of a push button key, the piezoelectric element bends at each press. As a result, as shown in FIG. 6, before the electric charge generated in the piezoelectric element due to the bending due to the press cannot be discharged, the electric charge is generated in the piezoelectric element due to the bending due to the next pressing, and the output voltage of the piezoelectric element increases. Will do.

  For this reason, when the output voltage of the piezoelectric element, that is, the pressing load, exceeds a predetermined threshold value Vref while increasing and the piezoelectric element functions as an actuator to vibrate the touch surface, the threshold value Vref is set. In some cases, it is detected that the output voltage of the piezoelectric element exceeds the threshold value Vref only at the first pressing or only at the first and second pressing (in the case of FIG. 6). The output voltage of the piezoelectric element remains in a state exceeding the threshold value Vref, and it is no longer detected that the output voltage exceeds the threshold value Vref.

  As a result, in the case of FIG. 6, the touch surface can be vibrated by causing the piezoelectric element to function as an actuator for the first and second presses, but for the subsequent continuous presses, the piezoelectric element is used as the actuator. It can no longer function. Therefore, a tactile sensation can be presented to the operator with respect to the first and second presses, but a tactile sensation cannot be presented with respect to the subsequent continuous presses.

Accordingly, an object of the present invention made in view of such points is to provide a tactile sensation presentation apparatus and a control method for the tactile sensation presentation apparatus that are appropriately configured so as to surely present a tactile sensation without giving an uncomfortable feeling to the operator. is there.

Invention of tactile sensation device according to a first aspect of achieving the above object, a piezoelectric element for the tactile sensation, and the piezoelectric element drive unit for driving the piezoelectric element, the piezoelectric element by the piezoelectric element drive unit A control unit that controls driving; a connection switching unit that selectively connects the piezoelectric element to the control unit or the piezoelectric element driving unit; and a discharge circuit that discharges charges accumulated in the piezoelectric element.
Wherein the control unit connects the piezoelectric element by the connection switching part to the piezoelectric element drive unit, the tactile presented by driving the piezoelectric element by the piezoelectric element drive unit, then the by the connection switching part The piezoelectric element is connected to the control unit, and the discharge circuit is controlled to discharge the electric charge accumulated in the piezoelectric element.
Furthermore, the invention of the control method of the tactile sensation providing apparatus according to the second aspect to achieve the above object comprises a piezoelectric element for presenting a tactile sensation, a piezoelectric element driving unit for driving the piezoelectric element, and the piezoelectric element driving unit A control unit for controlling the driving of the piezoelectric element by the switch, a connection switching unit for selectively connecting the piezoelectric element to the control unit or the piezoelectric element driving unit, and a discharge circuit for discharging charges accumulated in the piezoelectric element A tactile sensation presentation apparatus control method comprising:
Connecting the piezoelectric element to the piezoelectric element driving unit by the connection switching unit, and driving the piezoelectric element by the piezoelectric element driving unit to present a tactile sensation;
Then, the piezoelectric switching element is connected to the control unit by the connection switching unit, and the electric charge accumulated in the piezoelectric device is discharged by the discharge circuit.
In a preferred embodiment of the present invention, an input device for presenting a tactile sensation, a touch sensor for detecting a touch input, a piezoelectric element for presenting a tactile sensation attached to the touch sensor, and the piezoelectric element A piezoelectric element driving unit that drives the piezoelectric element, a control unit that controls driving of the piezoelectric element by the piezoelectric element driving unit, and a connection switching unit that selectively connects the piezoelectric element to the control unit or the piezoelectric element driving unit. A discharge circuit for discharging the electric charge accumulated in the piezoelectric element,
The control unit connects the piezoelectric element to the piezoelectric element driving unit by the connection switching unit, drives the piezoelectric element by the piezoelectric element driving unit, and presses the touch surface of the touch sensor. And then connecting the piezoelectric element to the control unit by the connection switching unit and controlling the discharge circuit to discharge the electric charge accumulated in the piezoelectric element. It is a feature.
Furthermore, in a preferred embodiment of the present invention, a touch sensor for detecting a touch input, a piezoelectric element for presenting a tactile sensation attached to the touch sensor, and a piezoelectric element driving unit for driving the piezoelectric element; A control unit that controls driving of the piezoelectric element by the piezoelectric element driving unit; a connection switching unit that selectively connects the piezoelectric element to the control unit or the piezoelectric element driving unit; A discharge circuit for discharging electric charge, and a control method of an input device comprising:
The piezoelectric element is connected to the piezoelectric element driving unit by the connection switching unit, and the piezoelectric element is driven by the piezoelectric element driving unit so that a tactile sensation is applied to a pressing target pressing the touch surface of the touch sensor. Present,
Thereafter, the connection switching unit connects the piezoelectric element to the control unit, and the discharge circuit controls the electric charge accumulated in the piezoelectric element to be discharged.

The discharge circuit has a switching element connected between the piezoelectric element and ground,
It is preferable that the control unit conducts the switching element for a predetermined time immediately after the piezoelectric element is vibrated by the piezoelectric element driving unit to discharge the electric charge accumulated in the piezoelectric element .

The discharge circuit preferably includes a resistance element connected between the piezoelectric element and ground .

According to the present invention, it is possible to prevent electric charges from continuing to be accumulated in the piezoelectric element, and it is possible to surely present a tactile sensation without causing the operator to feel uncomfortable.

It is a functional block diagram which shows schematic structure of the input device which concerns on 1st Embodiment of this invention. It is a circuit diagram which shows the structure of an example of the connection switching part and discharge circuit shown in FIG. 2 is a timing chart illustrating a schematic operation of the input device illustrated in FIG. 1. It is a circuit block diagram of the principal part of the input device which concerns on 2nd Embodiment of this invention. FIG. 2 is a cross-sectional view and a main part plan view of an essential part showing an example of a mounting structure of an input device according to the present invention. It is a figure which shows the change of the accumulation charge of the piezoelectric element explaining the subject which this invention tends to solve.

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

(First embodiment)
FIG. 1 is a functional block diagram showing a schematic configuration of an input device according to the first embodiment of the present invention. The input device includes a touch sensor 11, a display unit 12, a piezoelectric element 13, a connection switching unit 14, a piezoelectric element driving unit 15, a discharge circuit 16, and a control unit 17 that controls the operation of each unit.

  The touch sensor 11 is connected to the control unit 17, and under the control of the control unit 17, detects a touch input by a pressing target such as a finger on the touch surface of the touch sensor 11, and obtains position information of the touch position. This is supplied to the control unit 17. The touch sensor 11 is configured by a known type such as a resistive film type, a capacitance type, and an optical type, and is disposed on the display unit 12.

  The display unit 12 is connected to the control unit 17 and displays an input object such as an input button such as a push button switch (push button switch) under the control of the control unit 17. The display unit 12 is configured using, for example, a liquid crystal display panel or an organic EL display panel. Touch input to the input object displayed on the display unit 12 is detected by the control unit 17 based on position information output from the touch sensor 11.

  The piezoelectric element 13 is attached to the touch sensor 11 so as to be bent (distorted) when the touch surface of the touch sensor 11 is pressed. The piezoelectric element 13 is connected to the connection switching unit 14 and selectively connected to the control unit 17 or the piezoelectric element driving unit 15 via the connection switching unit 14.

  The connection switching unit 14 is configured to have a switch circuit or the like as will be described later, and selectively connects the piezoelectric element 13 to the control unit 17 or the piezoelectric element driving unit 15 under the control of the control unit 17. The piezoelectric element driving unit 15 includes a power amplifier or the like, and outputs a predetermined driving signal for vibrating the piezoelectric element 13 under the control of the control unit 17.

  In the state where the piezoelectric element 13 is connected to the control unit 17 via the connection switching unit 14, the output signal of the piezoelectric element 13, that is, the voltage due to the electric charge generated by pressing the touch surface of the touch sensor 11, It is supplied to the control unit 17. Further, in a state where the piezoelectric element 13 is connected to the piezoelectric element driving unit 15 via the connection switching unit 14, a driving signal from the piezoelectric element driving unit 15 is supplied to the piezoelectric element 13 and the piezoelectric element 13 is driven. The Thereby, the touch sensor 11 vibrates and a tactile sensation is presented to the pressing target pressing the touch surface.

  As will be described later, the discharge circuit 16 includes a switching element connected to the piezoelectric element 13, and charges (residual charges) accumulated in the piezoelectric element 13 under the control of the control unit 17. Discharge.

  The control unit 17 includes, for example, a CPU or the like, and controls the operation of each unit based on position information from the touch sensor 11, display information on the display unit 12, an output signal of the piezoelectric element 13, and the like.

  FIG. 2 is a circuit diagram showing a configuration example of the connection switching unit 14 and the discharge circuit 16 shown in FIG. The connection switching unit 14 is provided with two switch circuits 21 and 22 made of a semiconductor relay or the like, and an inverter 23. Each of the switch circuits 21 and 22 has an on / off contact, and the on / off contact of the switch circuit 21 is between the positive terminal of the piezoelectric element 13 and the output terminal (not shown) of the piezoelectric element driving unit 15. The on / off contact of the switch circuit 22 is connected between the positive terminal of the piezoelectric element 13 and the analog / digital conversion input terminal (not shown) of the control unit 17.

  The switch circuit 21 performs on / off control of the on / off contact via the inverter 23 by a switch switching signal a output from the control unit 17. The switch circuit 22 controls on / off of the on / off contact according to the switch switching signal a. Therefore, when one of the on / off contacts of the switch circuits 21 and 22 is in the on state, the other is in the off state.

  The discharge circuit 16 includes an AND (logical product) circuit 25, a resistor 26, and a discharge switching transistor 27. The AND circuit 25 receives the discharge control signal b output from the control unit 17 and the switch switching signal a described above, and supplies the output to the base of the switching transistor 27 via the resistor 26. The positive terminal of the piezoelectric element 13 is connected to the ground through the collector-emitter passage of the switching transistor 27.

  FIG. 3 is a timing chart showing a schematic operation of the input device according to the present embodiment. 3 shows the switch switching signal a and the discharge control signal b output from the control unit 17 and the output of the piezoelectric element 13 when the touch surface of the touch sensor 11 is continuously pressed and continuously input (continuous hitting). Signal (voltage). The control unit 17 always sets the switch switching signal a to the high (H) level and the discharge control signal b to the low (L) level. Thereby, the switch circuit 21 of the switching control unit 14 is turned off, the switch circuit 22 is turned on, and the piezoelectric element 13 is connected to the control unit 17. Further, the discharge circuit 16 sets the output of the AND circuit 25 to the L level and turns off the switching transistor 27.

  In this state, the control unit 17 monitors the output of the touch sensor 11 and the output signal (voltage) of the piezoelectric element 13. The positional information from the touch sensor 11 is input to the input object displayed on the display unit 12, and the output voltage of the piezoelectric element 13 corresponds to a reference load (for example, 1N) that provides tactile sensation. When it is detected that the threshold value Vref has been reached, the switch switching signal a is set to the L level. As a result, the switch circuit 21 of the switching control unit 14 is turned on and the switch circuit 22 is turned off to connect the piezoelectric element 13 to the piezoelectric element driving unit 15.

  In this state, the control unit 17 outputs a predetermined drive signal from the piezoelectric element driving unit 15 to drive the piezoelectric element 13. Thereby, the touch panel 11 is vibrated and a tactile sensation is presented to the pressing target pressing the touch surface. In addition, the control unit 17 performs predetermined processing on the input object in the display unit 12, for example, display mode change processing, display processing of a character corresponding to the input object in a predetermined display area, and application corresponding to the object. The execution process etc. are performed.

When the driving of the piezoelectric element 13 by the piezoelectric element driving unit 15 is completed, the control unit 17 sets the switch switching signal a to H level to turn off the switch circuit 21 and return the switch circuit 22 to on. As a result, the piezoelectric element 13 is disconnected from the piezoelectric element driving unit 15 and the piezoelectric element 13 is connected to the control unit 17. Here, the L level time T ₁ of the switch switching signal a is a time including the driving time of the piezoelectric element 13, and is set to be fixed (for example, about 5 ms) or by a driving signal corresponding to the tactile sensation to be presented. Automatically set according to the drive time.

Thereafter, the control unit 17, the switching signal a is in a state in H level, while the discharge control signal b of a predetermined discharge time T _2, and H level. Thus, during the discharge time T _2, the output of the AND circuit 25 of the discharge circuit 16 in the H level to turn on the switching transistor 27, a residual charge accumulated in the piezoelectric element 13, through the switching transistor 27 and discharge Let

Here, the time at which the switching signal a is switched from L level to H level, ie, from the point of time T ₁ of the L level of the switching signal a has been completed, to the discharge control signal b becomes the H level, that time until the discharge time T ₂ is started, the connection switching unit response time of the switch circuit 21 in the 14, or oN / oFF the contact of the switch circuit 21, taking into account the time, etc. to be reliably turned off from the on state And set. Moreover, the discharge time T ₂ to the discharge control signal b to H level, residual charge accumulated in the piezoelectric element 13 is almost fully discharged, so that the output voltage of the piezoelectric element 13 is substantially 0 volts, It is appropriately set (for example, about 1 ms) in accordance with the threshold value Vref, the drive signal of the piezoelectric element 13, the time interval between sequential pressing during continuous input, and the like.

  After the discharge process of the piezoelectric element 13, the control unit 17 monitors the output signal of the piezoelectric element 13, and controls each unit in the same manner as described above based on the output signal.

  As described above, according to the input device according to the present embodiment, the pressing load on the touch surface of the touch sensor 11 is detected by the piezoelectric element 13 using the piezoelectric positive effect and the piezoelectric reverse effect of the piezoelectric element 13. The parts are shared by using the load sensor and the actuator that vibrates the touch surface. Therefore, since the number of parts can be reduced, the cost can be reduced and the installation space for the parts can be reduced, so that the apparatus can be downsized.

  In addition, after the piezoelectric element 13 is driven and a tactile sensation is presented, the residual charge accumulated in the piezoelectric element 13 is discharged by the discharge circuit 16 in a state where the piezoelectric element 13 is electrically disconnected from the piezoelectric element driving unit 15. doing. Therefore, it is possible to prevent the electric charge from being continuously accumulated in the piezoelectric element 13, so that even in the case of continuous input, as shown in FIG. There is no sense of incongruity. In addition, when the piezoelectric element 13 is discharged, the connection between the piezoelectric element driving unit 15 and the piezoelectric element 13 is cut off, so that an output terminal such as a power amplifier constituting the piezoelectric element driving unit 15 may be grounded. Absent. Therefore, there is no adverse effect on the piezoelectric element driving unit 15.

(Second Embodiment)
FIG. 4 is a circuit configuration diagram of the main part of the input device according to the second embodiment of the present invention. This input device has the circuit configuration shown in FIG. 2 in which the discharge circuit 16 is configured with a resistance element 28 connected between the positive terminal of the piezoelectric element 13 and the ground. It is the same. Therefore, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

In the input device according to the present embodiment, since the residual charge of the piezoelectric element 13 is discharged through the resistance element 28, when the piezoelectric element 13 is driven by the piezoelectric element driving unit 15, the time T ₁ shown in FIG. Only, the piezoelectric element 13 is connected to the piezoelectric element driving unit 15. Thus, immediately after the piezoelectric element 13 is driven by the piezoelectric element driving unit 15, the discharge of the residual charge of the piezoelectric element 13 is started.

  Therefore, according to the present embodiment, the same effect as in the first embodiment can be obtained. In addition, compared with the first embodiment, the configuration of the discharge circuit 16 is simplified, and the discharge control signal b is not required. Therefore, the configuration and control are simplified, and the cost can be further reduced.

  Next, an example of the mounting structure of the input device according to the first embodiment or the second embodiment described above will be described with reference to FIG.

  FIG. 5 shows a schematic configuration example of the mounting structure of the touch sensor 11, the display unit 12, and the piezoelectric element 13 shown in FIG. 1. FIG. 5 (a) is a cross-sectional view of the main part, and FIG. FIG. The display unit 12 is housed and held in the housing 31. The touch sensor 11 is held on the display unit 12 via an insulator 32 made of an elastic member. In the present embodiment, the touch sensor 11 is held on the display unit 12 via the insulators 32 arranged at the four corners outside the display area A of the display unit 12 indicated by the phantom lines in FIG. To do.

  Further, the housing 31 is provided with an upper cover 33 so as to cover the surface area of the touch sensor 11 deviated from the display area of the display unit 12, and is made of an elastic member between the upper cover 33 and the touch sensor 11. A dust-proof insulator 34 is provided.

  In the touch sensor 11 shown in FIG. 5, the front surface member having the touch surface 11 a is made of, for example, a transparent film or glass, the back surface member is made of glass or acrylic, and the touch surface 11 a is pressed via the insulator 34. Then, a structure is used in which the pressing portion is bent (distorted) by a small amount in accordance with the pressing force, and the entire touch sensor 11 including the back member is bent by a small amount.

  The touch sensor 11 detects a pressing load on the touch surface 11a of the touch sensor 11 in the vicinity of one side or a plurality of sides covered with the upper cover 33, in this case, in the vicinity of the three sides on the back surface thereof. Are respectively attached to the piezoelectric elements 13 for presenting a tactile sensation to the pressing target pressing the touch surface 11a. In FIG. 5B, the casing 31, the upper cover 33, and the insulator 34 shown in FIG. 5A are not shown.

  Here, the three piezoelectric elements 13 are connected to the piezoelectric element driving unit via the connection switching unit and are driven by a common driving signal or driven by independent driving signals. Further, the outputs of the three piezoelectric elements 13 are supplied to the control unit in parallel via the connection switching unit. The discharge circuit is provided corresponding to each of the three piezoelectric elements 13.

  Then, the control unit calculates the pressing load based on the output signals of the three piezoelectric elements 13. This pressure load is preferably set so that, when the pressure sensation (feeling such as the hardness or softness of an object) felt by the operator is substantially the same at each position on the touch surface 11a, almost the same calculation result is obtained. The calculation is performed based on the average value of the output signals of the three piezoelectric elements 13 and the weighted addition value. Further, the three piezoelectric elements 13 are preferably driven by independent drive signals, and the operator has almost the same tactile sensation (sensation such as touch of an object) at each position on the touch surface 11a with almost the same pressure sensation. The amplitude and phase of each drive signal are appropriately changed according to the position and location of the touch surface 11a so that the same tactile sensation in which pressure sense and tactile sense are combined is obtained.

  Next, the reference of the pressing load that presents the tactile sensation and the drive signal that drives the piezoelectric element 13 in each of the above embodiments will be described.

  The reference of the pressing load that presents the tactile sensation can be appropriately set according to the load characteristics when the push button switch that the user wants to express is pressed, for example. For example, this reference may be set to the same load as the touch sensor 11 reacts to the touch input (the touch input reaction of the touch sensor 11 and the timing to present the tactile sensation are set the same), or the touch sensor 11 A load higher than the load that reacts to the touch input may be set (a setting that delays the timing of presenting the tactile sensation than the response of the touch input of the touch sensor 11). For example, in the case where the input device according to the present embodiment is applied to a mobile terminal, it is preferable that the touch sensor 11 be equal to or more than a load that reacts to a touch input (timing to present a tactile sensation rather than a touch input response of the touch sensor 11). Set to slow down). In addition, this load setting can be set freely by the user so that the elderly user can set it heavier (slower) and the user who frequently emails lightly (faster). .

  Moreover, the drive signal which drives the piezoelectric element 13 by the piezoelectric element drive part 15 can be suitably set according to the tactile sensation to present. For example, in the case of presenting a realistic click tactile sensation that can be felt as “cuckling” obtained when a push button switch used in a mobile terminal is pressed, for example, when the above reference load is applied, for example, 100 Hz to One cycle of a sine wave with a constant frequency of 200 Hz, preferably 170 Hz, is applied to the piezoelectric element 13 as a drive signal, and the touch surface of the touch sensor 11 is vibrated by about 15 μm with a reference pressing load applied. Accordingly, it is possible to present the operator with a real click feeling through the pressing object (pressing object) pressing the touch surface of the touch sensor 11 and recognize that the input operation has been completed. Similarly, in the case of presenting a click tactile sensation that is harder than “kachi”, a sine wave signal or a rectangular wave signal of about 200 Hz to 500 Hz is applied for one cycle as a drive signal.

  When presenting a tactile sensation other than the click tactile sensation, for example, when presenting a soft tactile sensation that can be felt as “Bull” or “Buni”, a sine wave signal of about 200 Hz to 500 Hz as a drive signal for two to three cycles Apply. Alternatively, in the case of presenting a tactile sensation that can be perceived as a vibration felt as “bull”, a sine wave signal of about 200 Hz to 500 Hz is applied as a drive signal for four cycles or more.

It is preferable that the drive signal information presenting these various tactile sensations is stored in a storage unit (not shown) so that the user can appropriately set a drive signal presenting a desired tactile sensation. Then, in accordance with the set driving signal, preferably automatically sets the time T ₁ of the L level of the switching signal a shown in FIG.

  Thus, pressure is stimulated until the load applied to the touch sensor 11 calculated based on the output of the piezoelectric element 13 satisfies a standard (eg, 1N) for presenting a tactile sensation. The element 13 is driven with a predetermined drive signal to vibrate the touch surface 11a to stimulate the sense of touch. Thereby, a tactile sensation is presented to the operator to recognize that the input operation has been completed. Therefore, for example, when a button switch such as a push button switch (push-type button switch) is drawn on the upper part of the touch sensor, the operator operates the touch sensor 11 in the same realistic manner as when the push button switch is operated. Since the input operation can be performed while obtaining the click feeling, there is no sense of incongruity. Further, since the input operation can be performed in conjunction with the consciousness of “pressing” the touch sensor 11, an input error due to simple pressing can be prevented.

  In addition, when the reference pressing load for presenting the tactile sensation is set higher than the load that the touch sensor 11 reacts to touch input (the timing at which the tactile sensation is presented is slower than the touch input reaction of the touch sensor 11), touch The input position is determined in accordance with the touch operation on the surface 11 a, the display mode of the input object at the corresponding portion of the display unit 12 is changed, and then the touch surface 11 a detected based on the output of the piezoelectric element 13. When the pressing load on the head satisfies the criteria for presenting a tactile sensation, the piezoelectric element 13 is driven to present a tactile sensation, and the input position is determined and predetermined processing (for example, execution of a program corresponding to the object) Processing) can be executed. In this case, the operator can confirm the selection of the input object by changing the display mode of the input object displayed on the display unit 12, and the selection is made by pressing the touch surface 11 a and presenting a click feeling. It can be recognized that the input object is determined (executed). Thereby, it is possible to prevent erroneous input by a so-called lost finger.

  When presenting the click feeling of the push button switch, when the pressing load falls below a predetermined reference even when released, the piezoelectric element 13 is driven by the same drive signal as that at the time of pressing, and the same clicking feeling as above. (In this case, release feel) can be presented. Of course, the release tactile sensation is not necessarily the same drive signal as the click tactile sensation.

  In this case, after presenting the click tactile sensation during pressing, the residual charge of the piezoelectric element 13 is not discharged, but after presenting the release tactile sensation during release, the residual charge of the piezoelectric element 13 is discharged by the discharge circuit 16. . In this way, it is possible to present a more realistic click tactile sensation that can be felt as “cut” when pressed and “click” when released.

  Here, the load standard for presenting the release tactile sensation can be set the same as the above-described load standard for presenting the click tactile sensation at the time of pressing, but preferably 50% to the load standard for presenting the click tactile sensation upon pressing. Set to 80% lower value. In this way, when the same position (input object) is continuously input (sequentially hit), the sequential input and the tactile sensation presentation timing match, and a realistic click tactile sensation without discomfort can be presented. In other words, by making the standard load that presents a tactile sensation at the time of release smaller than the standard load that presents a tactile sensation at the time of pressing, the reference load that presents a tactile sensation at the time of release is pressed. Occasionally, the operability during continuous input can be significantly improved by setting the load to be approximately 50% or more of the reference load that sometimes presents a tactile sensation. In addition, by making the reference load that presents a tactile sensation at the time of release approximately 80% or less of the reference load that presents a tactile sensation when pressed, it is possible to cope with minute load changes in the hold state during continuous input.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. For example, in FIG. 2, the switch circuits 21 and 22 can be configured by one switch circuit having two contacts. In the discharge circuit 16 shown in FIG. 2, the switching transistor 27 can also be configured using a semiconductor relay or the like. Furthermore, the piezoelectric element 12 can have a known structure such as a monomorph, a unimorph, a bimorph, and a laminated type in accordance with the area of the touch sensor 11, the vibration amplitude, and the like.

  The present invention can also be effectively applied to an input device that functions as a touch switch in which a touch sensor performs an on / off operation. Furthermore, the input device according to the present invention drives the piezoelectric element when a pressing load detected based on the output of the piezoelectric element satisfies a criterion for presenting a tactile sensation. Here, the case where the pressing load detected based on the output of the piezoelectric element satisfies the standard for presenting tactile sensation may be the time when the detected pressing load reaches a reference value for presenting tactile sensation. The detected pressing load may exceed a reference value that provides tactile sensation, or may be detected when a reference value that provides tactile sensation is detected based on the output of the piezoelectric element.

DESCRIPTION OF SYMBOLS 11 Touch sensor 11a Touch surface 12 Display part 13 Piezoelectric element 14 Connection switching part 15 Piezoelectric element drive part 16 Discharge circuit 17 Control part 31 Case 32 Insulator 33 Upper cover 34 Insulator

Claims (2)

A piezoelectric element for presenting a tactile sensation ;
A piezoelectric element driving unit for driving the piezoelectric element;
A control unit for controlling driving of the piezoelectric element by the piezoelectric element driving unit ;
A connection switching unit for selectively connecting the piezoelectric element to the control unit or the piezoelectric element driving unit;
A discharge circuit for discharging the charge accumulated in the piezoelectric element,
Wherein the control unit connects the piezoelectric element by the connection switching part to the piezoelectric element drive unit, the tactile presented by driving the piezoelectric element by the piezoelectric element drive unit, then the by the connection switching part Connecting the piezoelectric element to the control unit and controlling the discharge circuit to discharge the electric charge accumulated in the piezoelectric element;
A tactile sensation presentation apparatus characterized by that. A piezoelectric element for presenting a tactile sensation;
A piezoelectric element driving unit for driving the piezoelectric element;
A control unit for controlling driving of the piezoelectric element by the piezoelectric element driving unit;
A connection switching unit for selectively connecting the piezoelectric element to the control unit or the piezoelectric element driving unit;
A method for controlling a tactile sensation providing apparatus comprising: a discharge circuit that discharges charges accumulated in the piezoelectric element;
Connecting the piezoelectric element to the piezoelectric element driving unit by the connection switching unit, and driving the piezoelectric element by the piezoelectric element driving unit to present a tactile sensation;
Then, the piezoelectric switching element is connected to the control unit by the connection switching unit, and the electric charge accumulated in the piezoelectric element is discharged by the discharge circuit.
A tactile sensation presentation apparatus control method characterized by

Images