JPWO2018105639A1 - Tactile presentation device - Google Patents

Abstract

Provided is a tactile presentation device that appropriately detects a user's pressing operation and appropriately vibrates a diaphragm. The tactile sense presentation device includes a film, a diaphragm, a touch detection unit, a push-in operation detection unit, and a drive unit. The film is deformed in the surface direction by applying a voltage. The diaphragm is connected to the film, and is bent in the normal direction when the film is deformed in the surface direction. The touch detection unit detects a touch operation on the diaphragm. The push-in operation detection unit detects a push-in operation with respect to the diaphragm based on the voltage change of the film. The drive unit applies a drive signal to the film when the touch detection unit detects the touch operation and the push operation detection unit detects the push operation.

Description

  The present invention relates to a haptic presentation device that provides haptic feedback by transmitting vibration to a user.

  In recent years, a touch-sensitive keyboard or the like has been proposed that provides tactile feedback by transmitting vibrations when a user touches a key to feel the key “pressed”.

  For example, Patent Document 1 discloses a structure in which an end portion of a thin plate-like diaphragm is connected to a piezoelectric film and stress is applied to the diaphragm. In this case, the diaphragm vibrates in a direction (normal direction) perpendicular to the main surface due to expansion and contraction of the piezoelectric film. Since stress is applied to the diaphragm, it can be vibrated efficiently with respect to expansion and contraction of the piezoelectric film.

International Publication No. 2015/53247

  As shown in the example of Patent Document 1, a touch sensor for detecting a user's touch operation is provided on the touch surface of the diaphragm. Examples of the touch sensor include a membrane switch, a capacitive switch, a piezoelectric film type, and the like.

  Here, when the membrane switch is used, a film including the membrane switch is attached to the touch surface of the diaphragm. Since the film including the switch needs to have a certain thickness, the vibration of the diaphragm is restrained to reduce the amplitude.

  When a capacitance type switch is used, it may be detected that a user has touched the user just by touching the diaphragm. Therefore, even if the user does not intend to press the key, the diaphragm vibrates and a tactile sensation is presented.

  In addition, when a piezoelectric film having pyroelectricity is used, the heat of the user's finger may be transmitted to the piezoelectric film, and the touch operation may not be detected correctly.

  Therefore, an object of the present invention is to provide a tactile sense presentation device that appropriately detects a user's pressing operation and appropriately vibrates a diaphragm.

  The tactile sense presentation device of the present invention includes a film, a diaphragm, a touch detection unit, a push-in operation detection unit, and a drive unit. The film is deformed in the surface direction by applying a voltage. The diaphragm is connected to a film and is bent in the normal direction when the film is deformed in the surface direction. The touch detection unit detects a touch operation on the diaphragm. The push-in operation detection unit detects a touch operation on the diaphragm based on a voltage change of the film. The drive unit applies a drive signal to the film when the touch detection unit detects the touch operation and the push operation detection unit detects the push operation.

  When the user performs a touch operation, the tactile presentation device first detects the touch operation in the touch detection unit. When the user intends to press the key, the user presses the diaphragm. When the user pushes in the diaphragm, the film is deformed in the surface direction. Conversely, a film that deforms in the plane direction when a voltage is applied generates a voltage when the film is deformed in the plane direction. Therefore, the tactile sense presentation device detects a push-in operation by detecting a change in voltage. When the touch detection unit detects a touch operation and the push operation detection unit detects a push operation, the tactile sense presentation device applies drive vibration to the film to vibrate the diaphragm. In this structure, since there is a gap between the diaphragm and the piezoelectric film, the heat of the finger is not easily transmitted to the piezoelectric film, and the influence of pyroelectricity can be greatly reduced.

  As a result, the tactile sense presentation device of the present invention presents the tactile sense only when the user deliberately presses the diaphragm, even when a switch that reacts by touching, such as a capacitive switch, is used. Can be performed. Also, when the tactile sense presentation device is a keyboard, it is possible to speed up character output when pressing is detected by waiting for input of a nearby key when the capacitive switch reacts. .

  In the case where a capacitance type switch is used, the capacitance type switch can be built in the diaphragm. In this case, the tactile sensation presentation device does not need to attach a thick film to the diaphragm like a membrane switch, so that the vibration of the diaphragm is not constrained and the amplitude is not reduced.

  Examples of the film that deforms in the plane direction when a voltage is applied include a piezoelectric film, an electrostrictive film, an electret film, a composite film, and an electroactive polymer film. Moreover, it is good also as an aspect which affixes the material (for example, piezoelectric film) which has piezoelectricity on the main surface of the resin film which does not have piezoelectricity, and connects the said resin film to a diaphragm.

  According to this invention, a user's pressing operation can be detected appropriately, and a diaphragm can be vibrated appropriately.

1 is an external perspective view of a tactile presentation device 10. FIG. FIG. 2A is a side view of the haptic presentation device 10, and FIG. 2B is a front view of the haptic presentation device 10. FIGS. 3A, 3 </ b> B, and 3 </ b> C are operation explanatory views of the tactile sense presentation device 10. 1 is a block diagram illustrating a configuration of a tactile sense presentation device 10. FIGS. 5A and 5B are block diagrams illustrating the configuration of the tactile sense presentation device 10 according to the first modification. It is a figure which shows the state of signal ON / OFF of each structure. It is a perspective view of 10 A of tactile sense presentation apparatuses. 8A and 8B are side views of the tactile presentation device 10A.

  FIG. 1 is an external perspective view of a tactile presentation device 10 according to the first embodiment. FIG. 2A is a side view of the tactile sense presentation device 10, and FIG. 2B is a front view.

  The tactile presentation device 10 includes a piezoelectric film 20 and a diaphragm 40. The tactile sense presentation device 10 is a so-called keyboard. A plurality of key images 80 are displayed on the surface of the diaphragm 40 at positions corresponding to the key arrangement. The key image 80 is printed on the first main surface of the diaphragm 40. Alternatively, the key image 80 may be printed on a film and the film may be attached to the first main surface of the diaphragm 40.

  The diaphragm 40 is made of a material such as acrylic resin, PET, polycarbonate, glass epoxy, FRP (GFRP, CFRP, AFRP, DFRP, or XFRP), glass, or metal. A touch sensor 50 may be built in the diaphragm 40. The touch sensor 50 is an example of a touch detection unit, and includes, for example, a capacitance sensor. The diaphragm 40 has a rectangular shape in plan view. The diaphragm 40 has both ends in the length direction fixed to the piezoelectric film 20 on the second main surface.

  The piezoelectric film 20 has a rectangular shape in plan view like the diaphragm 40. The piezoelectric film 20 is made of, for example, polyvinylidene fluoride (PVDF). In addition, the piezoelectric film 20 may be formed of a chiral polymer. For example, L-type polylactic acid (PLLA) is used as the chiral polymer.

  When PVDF is used for the piezoelectric film 20, since PVDF has water resistance, for example, an electronic device including a tactile sensation display device has little variation in click feeling due to the influence of the humidity environment.

  In addition, when PLLA is used for the piezoelectric film 20, PLLA is a highly permeable material. Therefore, if the electrode and diaphragm added to PLLA are transparent materials, when manufacturing functional parts that vibrate, etc. Since the internal state of the functional component can be visually confirmed, it is easy to manufacture. Moreover, the position of the key can be visually recognized even in a dark place by disposing a light source such as a light inside the functional component.

  If the piezoelectric film 20 is composed of PLLA, as shown in FIG. 2B, the piezoelectric film 20 is cut so that each outer periphery is approximately 45 ° with respect to the stretching direction, thereby forming a rectangular shape. Give piezoelectricity.

  The diaphragm 40 is connected to the piezoelectric film 20 at the end in the length direction. The piezoelectric film 20 is an example of a film that deforms in the plane direction when a voltage is applied. As shown in FIG. 2A, the diaphragm 40 is curved and protrudes on the opposite side (first main surface side) with respect to the second main surface on the side where the piezoelectric film 20 exists. The piezoelectric film 20 is fixed.

  With this configuration, a hollow region 100 is formed between the diaphragm 40 and the piezoelectric film 20. The side on which the diaphragm 40 is located is the front side (touch surface side) of the tactile presentation device 10, and the side on which the piezoelectric film 20 is disposed is the back side of the tactile sense presentation device 10.

  However, in the present embodiment, the curved state of the vibration plate 40 is exaggerated for the sake of explanation, and actually, the main surface of the vibration plate 40 and the main surface of the piezoelectric film 20 are substantially parallel in appearance. It is.

  The diaphragm 40 is fixed to the piezoelectric film 20 with the flat plate surface being curved. Therefore, it is fixed to the piezoelectric film 20 with bending stress applied as indicated by the white arrow F901 in FIG. Further, the piezoelectric film 20 is in a state in which a tensile force is applied in the length direction of the main surface of the piezoelectric film 20 as indicated by an outline arrow S901 in FIG.

  FIGS. 3A, 3 </ b> B, and 3 </ b> C are operation explanatory views of the tactile sense presentation device 10. FIG. 3A shows a state at the timing when the piezoelectric film 20 is contracted by the drive signal. FIG. 3B shows a state where no drive signal is applied or the amplitude of the drive signal is zero. FIG. 3C shows a state at the timing when the piezoelectric film 20 is extended by the drive signal. FIG. 4 is a block diagram illustrating a configuration of the tactile sense presentation device 10.

  The tactile sense presentation device 10 includes a touch sensor 50, a voltage detection circuit 81, a signal processing circuit 82, and a drive unit 83. The touch sensor 50 is built in the diaphragm 40 and detects a user's touch operation. The touch sensor 50 is arranged corresponding to the position of each key in the key image 80. When the user touches the position of each key on the diaphragm 40, the touch sensor 50 first detects a touch operation. When the user intends to press the key, the user presses the diaphragm 40. When the user pushes the diaphragm 40, the piezoelectric film 20 extends in the length direction. When the piezoelectric film 20 extends in the length direction, electric charges are generated. The voltage detection circuit 81 detects electric charges (voltage) generated in the piezoelectric film 20. The signal processing circuit 82 determines that the user's push-in operation has been performed when the voltage changes to a predetermined threshold value or more. When the touch operation is detected by the touch sensor 50 and the push operation is detected by the voltage detection circuit 81, the signal processing circuit 82 applies a driving vibration to the piezoelectric film 20 to the driving unit 83, and thereby the diaphragm 40 is vibrated. In addition, about a threshold value, it is good also as the same value with all the keys, and you may assign a different threshold value with a key. For example, the operability of the user can be improved by lowering the threshold for a key that is difficult to detect a press and increasing the threshold for a key that is easy to detect a press. Further, the user can obtain a tactile sensation similar to a mechanical switch by an operation of pushing.

  When the drive unit 83 applies a drive signal to the piezoelectric film 20 and applies an electric field in the first direction of the piezoelectric film 20, the piezoelectric film 20 moves to the diaphragm 40 as indicated by an arrow S 911 in FIG. Shrink along the direction perpendicular to the fixed end. The diaphragm 40 is pulled in the central direction from a portion (end portion in the length direction) fixed to the piezoelectric film 20. Thereby, the diaphragm 40 is curved so as to protrude further forward as indicated by an arrow F911 in FIG.

  On the other hand, when the drive unit 83 applies a drive signal to the piezoelectric film 20 and applies an electric field in a second direction opposite to the first direction, the piezoelectric film 20 as shown by an arrow S912 in FIG. Extends along a direction orthogonal to the fixed end of the diaphragm 40. The diaphragm 40 is pulled from the center to a place (end in the length direction) fixed to the piezoelectric film 20. Thereby, the diaphragm 40 is in a curved state in which the forward protrusion amount is reduced as indicated by an arrow F912 in FIG.

  Therefore, the vibration plate 40 changes to the state shown in FIG. 3A or the state shown in FIG. 3C based on the state shown in FIG. It vibrates along the direction (normal direction perpendicular to the main surface of the diaphragm 40). Thereby, the vibration according to the drive signal is transmitted to the user via the diaphragm 40.

  Since the diaphragm 40 is given a stationary bending stress in a non-operating state, the force applied to the diaphragm 40 when the piezoelectric film 20 is stretched is in the same direction as the bending stress. Therefore, the tactile sense presentation device 10 can vibrate the diaphragm 40 efficiently and can transmit a strong vibration to some extent even when a piezoelectric film is used. In addition, the tactile sense presentation device 10 can be made thinner than vibration caused by a motor or the like.

  Note that the hollow region 100 may be filled with a soft resin such as a silicone gel having heat insulation properties to suppress sound generated when the piezoelectric film 20 and the diaphragm 40 vibrate.

  As described above, the tactile sense presentation device 10 according to the present embodiment provides tactile feedback when the user pushes the diaphragm 40. As a result, the tactile sense presentation device 10 deliberately pushes the diaphragm even when the touch sensor 50 uses a switch such as a capacitance-type switch that may react when touched. Only in this case, tactile sensation can be presented. In addition, since the touch-sensitive presentation device 10 has a gap between the diaphragm and the piezoelectric film with which the finger contacts, the influence of pyroelectricity due to the heat of the finger can be greatly reduced.

  In the case where a capacitive switch is used as the touch detection unit, the capacitive switch can be incorporated in the diaphragm 40. In this case, the tactile sense presentation device 10 does not need to attach a thick film to the diaphragm like a membrane switch, so that the vibration of the diaphragm is not constrained and the amplitude is not reduced. Note that the film on which the key image 80 is printed is much thinner than the film with the built-in membrane switch, so that the vibration of the diaphragm 40 is not hindered. Further, since the capacitive switch has no pyroelectricity, even if it is provided on the touch surface of the diaphragm 40 that the user touches (or the position close to the first main surface in the interior), the user's touch operation Can be detected appropriately.

  Next, FIGS. 5A and 5B are block diagrams illustrating the configuration of the tactile sense presentation device 10 according to the first modification. FIG. 6 is a diagram illustrating a signal on / off state of each configuration.

  The tactile sense presentation device 10 according to Modification 1 includes a switch 85 in addition to the configuration shown in FIG. The switch 85 is connected to the piezoelectric film 20, the voltage detection circuit 81, and the drive unit 83. The switch 85 selectively connects the electrode provided on the piezoelectric film 20 to the voltage detection circuit 81 or the drive unit 83.

  As shown in FIGS. 5A and 6, the signal processing circuit 82 turns off the switch 85, the piezoelectric element 83, and the piezoelectric element 82 when the voltage detection circuit 81 detects the pushing operation of the user. The film 20 and the voltage detection circuit 81 are electrically disconnected.

  Then, as shown in FIGS. 5B and 6, the signal processing circuit 82 detects the user's touch operation in the touch sensor 50 and the voltage detection circuit 81 detects the user's push-in operation. In addition, the switch 85 is turned on to electrically connect the drive unit 83 and the piezoelectric film 20. Immediately after a signal is output from the drive unit 83 to the piezoelectric film 20, the switch 85 is switched from the state shown in FIG. 5B to the state shown in FIG.

  Thereby, it is possible to prevent the drive signal from being input to the voltage detection circuit 81. Therefore, a high-voltage drive signal does not flow through the voltage detection circuit 81, and the voltage detection circuit 81 can be protected.

  Further, the switch may be connected between the driving unit and the piezoelectric film, or between the piezoelectric film and the voltage detection circuit, and the on / off thereof may be controlled by the CPU. As shown in FIG. 5B, it is desirable to have one of these switches (3-terminal type). By using the switches as shown in FIGS. 5A and 5B, even if a signal is accidentally sent from the signal processing circuit 85 to the piezoelectric film, the output from the drive unit 83 is the voltage detection circuit 81. This is because there is no fear that excessive power will be erroneously input.

  Next, FIG. 7 is a perspective view of a tactile sense presentation device 10A according to a modification. 8A and 8B are side views of the tactile presentation device 10A. In this example, two spacers 70 are disposed in the hollow region 100 where the diaphragm 40 and the piezoelectric film 20 face each other. The spacer 70 has a prismatic shape that is long in the width direction of the tactile sense presentation device 10. The spacer 70 is made of, for example, metal, PET, polycarbonate (PC), or ABS resin.

  As shown in FIG. 8A, the spacer 70 is sandwiched between the lower surface of the diaphragm 40 and the upper surface of the piezoelectric film 20. When the piezoelectric film 20 is not driven, the spacer 70 pushes the piezoelectric film 20 downward to apply tension.

  As shown in FIG. 8A, when the piezoelectric film 20 is contracted, the center in the length direction of the diaphragm 40 is displaced upward. When the piezoelectric film 20 is extended, the center in the length direction of the diaphragm 40 is displaced downward. As shown in FIG. 8B, when the piezoelectric film 20 is extended, the center in the length direction of the diaphragm 40 is displaced downward.

  The diaphragm 40 may project in the normal direction as shown in FIG. 8A without applying a drive signal to the piezoelectric film 20 (steady state), or as shown in FIG. 8B. , It may be in a flat state. The diaphragm 40 may protrude downward without applying a drive signal to the piezoelectric film 20 (steady state).

  Even in the tactile sense presentation device 10A having such a structure, tactile feedback is performed when the user pushes the diaphragm 40. As a result, even in the tactile sense presentation device 10A, even when a touch detection unit such as a capacitive switch is used, the user intentionally moves the diaphragm. The tactile sensation can be presented only when pushed. When a capacitive switch is used as the touch detection unit, the capacitive switch can be incorporated in the diaphragm.

  In this embodiment, a piezoelectric film is shown as an example of a “film that deforms in a plane direction when a voltage is applied”, but a “film that deforms in a plane direction when a voltage is applied” is limited to a piezoelectric film. is not. Other examples of the “film that deforms in the plane direction when a voltage is applied” include an electrostrictive film, an electret film, a composite film, and an electroactive polymer film. The electroactive film is a film that generates stress by electrical driving or a film that generates displacement by deformation. Specifically, there are an electrostrictive film, a composite material (a material obtained by resin-molding piezoelectric ceramics), an electrically driven elastomer, or a liquid crystal elastomer.

  In this embodiment, the example in which the piezoelectric film 20 is directly connected to the vibration plate 40 has been shown. However, the piezoelectric film 20 is indirectly connected to the vibration plate 40 via another resin film that does not have piezoelectricity. It is good also as an aspect made. For example, the piezoelectric film 20 may be attached to the main surface of the resin film, and the end of the resin film may be connected to the vibration plate 40. Of course, in addition, a film such as an electrostrictive film, an electret film, a composite film, or an electroactive polymer film is attached to the main surface of the resin film, and the end of the resin film is connected to the diaphragm 40. It is also possible to adopt an aspect.

  In the present embodiment, an example of a structure in which stress is generated in the diaphragm is shown, but it is not essential that stress is generated in the diaphragm. For example, the present invention can be applied even to a unimorph type vibration structure in which a piezoelectric film and a diaphragm are bonded. The present invention is also applicable to a horizontally driven structure as disclosed in WO2016 / 067832. Since the piezoelectric film is arranged on the non-operation surface side of the diaphragm, the heat of the finger is hardly transmitted to the piezoelectric film.

  The “film that deforms in the plane direction when a voltage is applied” can also be realized by using, for example, piezoelectric ceramics and a resin film. For example, it can be realized by connecting a plurality of resin films via piezoelectric ceramics and connecting each of the plurality of resin films to the diaphragm 40.

  Furthermore, the “film that deforms in the plane direction when a voltage is applied” may be a single layer or may be laminated. In particular, stronger vibration can be obtained by increasing the number of stacked layers.

  Moreover, although this embodiment illustrated the tactile-sensation presentation apparatus, the vibration structure shown in this embodiment can also be applied to a speaker. For example, when the user applies pressure, the diaphragm emits a sound by vibrating in the normal direction for a certain time at an audible frequency. In this case, application to a thin crime prevention buzzer is conceivable. Further, for example, the signal processing circuit 82 may output a signal for haptic presentation and then output a signal having an audible frequency to sound a security buzzer.

DESCRIPTION OF SYMBOLS 10,10A ... Tactile sense presentation apparatus 20 ... Piezoelectric film 40 ... Diaphragm 50 ... Touch sensor 70 ... Spacer 80 ... Key image 81 ... Voltage detection circuit 82 ... Signal processing circuit 83 ... Drive part 85 ... Switch 100 ... Hollow area

Further, the switch may be connected between the driving unit and the piezoelectric film, or between the piezoelectric film and the voltage detection circuit, and the on / off thereof may be controlled by the CPU. As shown in FIG. 5B, it is desirable to have one of these switches (3-terminal type). By using the switches as shown in FIGS. 5A and 5B, even if a signal is erroneously sent from the signal processing circuit 82 to the piezoelectric film, the output from the drive unit 83 is the voltage detection circuit 81. This is because there is no fear that excessive power will be erroneously input.

Claims (5)

A film that deforms in the surface direction by applying voltage;
A diaphragm that is connected to the film and is deformed in the normal direction when the film is deformed in the surface direction; and
A touch detection unit for detecting a touch operation on the diaphragm;
Based on the voltage change of the film, a pressing operation detection unit that detects a pressing operation on the diaphragm,
A tactile sense presentation device comprising: a drive unit that detects a touch operation by the first touch detection unit and applies a drive signal to the film when the push operation is detected by the push operation detection unit.   The tactile sense presentation device according to claim 1, wherein the touch detection unit is built in the diaphragm.   The tactile sense presentation device according to claim 2, wherein the film is provided on a side opposite to a touch surface of the diaphragm. The touch detection unit is a switch including a non-pyroelectric material provided on the first main surface side of the diaphragm,
The tactile sense presentation device according to claim 1, wherein the film is provided on a second main surface side of the diaphragm.   5. The device according to claim 1, further comprising: a connection blocking unit that blocks an electrical connection between the film and the push-in operation detection unit when the driving unit applies the driving signal to the film. The tactile sense presentation device described.

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