Tactile sensation presenting element and tactile sensation presenting device

Abstract

To provide vibration type tactile sensation presenting elements that are capable of accurately presenting tactile sensations in minute regions.SOLUTION: A tactile sensation presenting element includes: a vibrator layer; and a first electrode layer and a second electrode layer located so as to face each other across the vibrator layer. At least one of the first electrode layer and the second electrode layer includes a plurality of electrodes that are electrically independent of one another. The vibrator layer includes a plurality of unit regions, in each of which occurrence of vibration can be independently controlled. The tactile sensation presenting element further includes a plurality of protrusions located opposite to the vibrator layer relative to the first electrode layer.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a tactile presentation element, and particularly to a tactile presentation element that presents a sense of touch by vibration stimulation. The present invention also relates to a tactile presentation device including such a tactile presentation element.

Background Art

[0002] In recent years, tactile presentation elements (sometimes called "haptic devices") that can present a sense of touch to a user have attracted attention and are being increasingly used in many applications such as medical treatment, education, entertainment, and remote operation. Several methods are known as tactile presentation elements.

[0003] A method of giving vibration to a user, that is, presenting a sense of touch by vibration stimulation (hereinafter referred to as the "vibration method") is one of the most promising techniques because of the small individual differences in the ease of feeling the sense of touch and excellent safety. A tactile presentation element using the vibration method is disclosed in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a vibration-type tactile presentation element, tactile presentation is performed by generating vibration by an actuator (for example, a piezoelectric element) while bringing a specific part of the human body (for example, a finger) into contact with the tactile presentation element. However, there is a problem that the user feels as if vibration is occurring at a location far from the distance between the actual vibrating part and the specific part. In addition, there is also a problem that the user feels vibration in a wider range than the actual vibrating part. Thus, in a vibration-type tactile presentation element, it is difficult to accurately present tactile sensation in a minute area.

[0006] An embodiment of the present invention has been made in view of the above problems, and an object thereof is to provide a vibration-type tactile presentation element capable of accurately presenting tactile sensation in a minute area.

Means for Solving the Problems

[0007] This specification discloses a tactile presentation element and a tactile presentation device described in the following items.

[0008] [Item 1] A vibrating body layer, A first electrode layer and a second electrode layer arranged to face each other via the vibrating body layer, A tactile presentation element comprising: At least one of the first electrode layer and the second electrode layer includes a plurality of electrodes electrically independent of each other, The vibrating body layer includes a plurality of unit regions in which generation of vibration can be controlled independently of each other, A tactile presentation element further comprising a plurality of protrusions arranged on the side opposite to the vibrating body layer with respect to the first electrode layer.

[0009] [Item 2] The tactile presentation element according to Item 1, wherein the plurality of protrusions do not overlap the center of each of the plurality of unit regions in a plan view.

[0010] [Item 3] The tactile presentation element according to item 1 or 2, wherein the plurality of protrusions include at least one first protrusion arranged so as to straddle the outer edge of at least one of the plurality of unit regions in a plan view.

[0011] [Item 4] The at least one first protrusion is a plurality of first protrusions, Each of the plurality of unit regions is substantially rectangular in a plan view, The tactile presentation element according to item 3, wherein one or more of the plurality of first protrusions straddle each side of each of the plurality of unit regions in a plan view.

[0012] [Item 5] The tactile presentation element according to any one of items 1 to 4, further comprising a first substrate disposed between the first electrode layer and the plurality of protrusions and supporting the first electrode layer.

[0013] [Item 6] A second substrate is further provided, which is disposed on the side opposite to the piezoelectric layer with respect to the second electrode layer and supports the second electrode layer, The tactile presentation element according to any one of items 1 to 5, wherein the thickness h [mm] of the second substrate and the Young's modulus E [GPa] of the second substrate satisfy the relationship of E·h≤1.95.

[0014] [Item 7] Each of the plurality of unit regions is substantially rectangular in a plan view, The tactile presentation element according to any one of items 1 to 6, wherein the height of each of the plurality of protrusions is not less than twice the length of the shortest side among the plurality of sides of each unit region in a plan view.

[0015] [Item 8] Each of the plurality of unit regions is substantially rectangular in a plan view, The tactile presentation element according to any one of items 1 to 6, wherein the height of each of the plurality of protrusions is not less than three times the length of the shortest side among the plurality of sides of each unit region in a plan view.

[0016] [Item 9] The cross-section of each of the plurality of protrusions has a substantially the same shape over the height direction of each protrusion, The cross-sectional area A and height H of each of the plurality of protrusions satisfy the relation of H≧(2·A 0.5 ) / π, and the tactile presentation element according to any one of Items 1 to 8.

[0017] [Item 10] The shape of the cross-section of each of the plurality of protrusions is substantially circular, substantially elliptical, substantially rectangular, substantially equilateral triangular, or substantially regular convex polygonal, and the tactile presentation element according to Item 9.

[0018] [Item 11] The Young's modulus of each of the plurality of protrusions is 20 GPa or less, and the tactile presentation element according to any one of Items 1 to 10.

[0019] [Item 12] The plurality of electrodes are a plurality of unit electrodes each corresponding to each of the plurality of unit regions, and the tactile presentation element according to any one of Items 1 to 11.

[0020] [Item 13] The plurality of unit electrodes are 9 or more unit electrodes arranged in m rows and n columns (m and n are each an integer of 3 or more), and the tactile presentation element according to Item 12.

[0021] [Item 14] Each of the first electrode layer and the second electrode layer includes the plurality of electrodes, The plurality of electrodes included in the first electrode layer are a plurality of first strip electrodes extending along a predetermined direction, The plurality of electrodes included in the second electrode layer are a plurality of second strip electrodes extending along a direction intersecting the predetermined direction, and the tactile presentation element according to any one of Items 1 to 11.

[0022] [Item 15] A second substrate that is disposed on the side opposite to the piezoelectric layer with respect to the second electrode layer and supports the second electrode layer, the second substrate having a first region that overlaps in plan view with a region including the plurality of unit regions of the vibrating body layer and a second region that is located outside the first region in plan view, A fixture that is joined to the second region of the second substrate and fixes the second region, The tactile presentation element according to any one of items 1 to 14, further comprising the fixture.

[0023] [Item 16] The first electrode layer includes the plurality of unit electrodes, The second electrode layer includes only a single common electrode, The common electrode has a first region that overlaps in plan view with a region including the plurality of unit regions of the vibrating body layer and a second region that is located outside the first region in plan view, The tactile presentation element according to item 12 or 13, further comprising a fixture that is joined to the second region of the common electrode and fixes the second region.

[0024] [Item 17] The tactile presentation element according to any one of items 1 to 16, wherein the vibrating body layer is a piezoelectric layer formed from a piezoelectric material.

[0025] [Item 18] The tactile presentation element according to item 17, wherein the piezoelectric layer includes a plurality of portions spaced apart from each other.

[0026] [Item 19] The tactile presentation element according to any one of items 1 to 16, wherein the vibrating body layer includes an induction coil for each of the plurality of unit regions.

[0027] [Item 20] The tactile presentation element according to any one of items 1 to 19, A control device that controls the tactile presentation element, A tactile presentation device comprising the control device. [Advantages of the Invention]

[0028] According to an embodiment of the present invention, it is possible to provide a vibration-type tactile presentation element that can accurately present a sense of touch in a minute area.

Brief Description of the Drawings

[0029]

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Mode for Carrying Out the Invention

[0030] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments.

[0031] Referring to FIG. 1, a tactile display device 100 including a tactile presentation element 1 according to an embodiment of the present invention will be described. FIG. 1 is a block diagram schematically showing the tactile display device 100. In addition to the tactile display device 100, a personal computer (PC) 210 and a head-mounted display (HMD) 220 are also shown in FIG. 1.

[0032] As shown in FIG. 1, the tactile display device 100 includes at least one tactile presentation element 1 and a control device 2 that controls the tactile presentation element 1. In the illustrated example, the tactile display device 100 includes a plurality of tactile presentation elements 1, more specifically, five tactile presentation elements 1. Note that the number of the tactile presentation elements 1 is not limited to five.

[0033] When the tactile display device 100 is used, the five tactile presentation elements 1 are arranged so as to be in contact with the fingertips of the five fingers F of the user's hand H (shown by a dotted line in FIG. 1). Each tactile presentation element 1 presents a tactile sensation by vibration stimulation to the fingertip abdomen of one finger F. Here, the "fingertip abdomen" refers to a region fp that is beyond the first joint j1 of the finger F and is located closer to the palm side than the center when the finger F is viewed from the side, as shown in FIG. 2.

[0034] The control device 2 controls the tactile presentation element 1. The control device 2 controls the tactile presentation element 1 based on a control signal transmitted from the PC 210. Data communication between the control device 2 and the PC 210 may be performed by wireless communication or by wired communication. The wireless communication and the wired communication can be performed in accordance with various known communication standards. The control device 2 is realized by, for example, a microcomputer.

[0035] The tactile presentation element 1 is wired using a flexible substrate, wiring, etc. so as not to interfere with the movement of the hand H. The control device 2 can be arranged, for example, at a portion corresponding to the user's arm. The tactile presentation element 1 and the control device 2 may be integrated as a glove.

[0036] The PC 210 outputs a video signal to the HMD 220, and the HMD 220 performs display based on the received video signal. The HMD 220 also outputs position tracking data or the like, which is information regarding the position of the HMD 220, to the PC 210. Data communication between the PC 210 and the HMD 220 may be performed by wireless communication or by wired communication.

[0037] Here, an example is shown in which the tactile presentation device 100 presents a tactile sensation in conjunction with the display by the HMD 220, but the use of the tactile presentation device 100 is not limited to this.

[0038] With reference to FIGS. 3, 4A, and 4B, the specific configuration of the tactile presentation element 1 will be described. FIG. 3 is a cross-sectional view schematically showing the tactile presentation element 1. FIGS. 4A and 4B are plan views schematically showing the tactile presentation element 1, respectively, and are views of the tactile presentation element 1 seen from the front side. In FIG. 4B, a part of the components of the tactile presentation element 1 (the first substrate 40 and the protrusions 50, which will be described later) is omitted.

[0039] As shown in FIGS. 3, 4A, and 4B, the tactile presentation element 1 includes a vibrating body layer 10, a first electrode layer 20, a second electrode layer 30, and a first substrate 40. The tactile presentation element 1 further includes a plurality of protrusions 50 and fixtures 60. In the illustrated example, the tactile presentation element 1 is substantially rectangular in plan view, but the planar shape of the tactile presentation element 1 is not limited to being substantially rectangular.

[0040] The vibrating body layer 10 is a layer in which physical deformation occurs in response to an applied voltage or current, thereby generating vibration. Here, the vibrating body layer 10 is a piezoelectric layer formed from a piezoelectric material. As the piezoelectric material, various known piezoelectric materials can be used. For example, piezoelectric ceramics such as zinc zirconate titanate (PZT) and barium titanate (BaTiO3) can be preferably used. Further, the piezoelectric material may be one in which particles of piezoelectric ceramics are dispersed in a resin material. Furthermore, a piezoelectric material other than piezoelectric ceramics (for example, a piezoelectric single crystal such as quartz) may be used.

[0041] There is no particular limitation on the thickness of the piezoelectric layer 10. When using piezoelectric ceramics as the piezoelectric material, from the viewpoint of ensuring sufficient torque, the thickness of the piezoelectric layer 10 is preferably, for example, 0.2 mm or more, and from the viewpoint of ensuring the displacement amount or reducing the driving voltage, it is preferably, for example, 0.19 mm or less. Further, when using a material in which particles of piezoelectric ceramics are dispersed in a resin material as the piezoelectric material, from the viewpoint of ensuring sufficient torque, the thickness of the piezoelectric layer 10 is preferably, for example, 0.50 mm or more, and from the viewpoint of ensuring the displacement amount or reducing the driving voltage, it is preferably, for example, 0.25 mm or less.

[0042] Note that the vibrating body layer is not limited to the exemplified ones. An organic actuator using PVDF (polyvinylidene fluoride) or an ion conductive polymer, or a layer containing a minute induction coil as described later may be used as the vibrating body layer. Since PVDF is a kind of piezoelectric material, the organic actuator using PVDF can also be referred to as a piezoelectric layer.

[0043] The piezoelectric layer 10 has two main surfaces 10a and 10b facing each other. Hereinafter, of these main surfaces 10a and 10b, the main surface 10a located on the front side (finger F side) is referred to as the "first main surface", and the main surface 10b located on the back side is referred to as the "second main surface".

[0044] The first electrode layer 20 and the second electrode layer 30 are arranged to face each other with the piezoelectric layer 10 interposed therebetween. The first electrode layer 20 is provided so as to be in contact with the first main surface 10a of the piezoelectric layer 10. The second electrode layer 30 is provided so as to be in contact with the second main surface 10b of the piezoelectric layer 10.

[0045] The first electrode layer 20 is divided into a plurality of electrodes 21 that are electrically independent of each other. In the illustrated example, the plurality of electrodes 21 are 25 electrodes 21 arranged in a 5-row and 5-column pattern, and each electrode 21 is substantially rectangular (more specifically, substantially square) in plan view. Of course, the number and shape of the electrodes 21 are not limited to those exemplified here. The first electrode layer 20 can be formed from various known conductive materials, for example, metals such as copper (Cu), nickel (Ni), silver (Ag), gold (Au), alloys such as Al-Nd alloy (aluminum-neodymium alloy), or metal oxides such as indium tin oxide (ITO) can be preferably formed. There is no particular limitation on the thickness of the first electrode layer 20 including the plurality of electrodes 21, but it is, for example, 50 nm or more and 200 nm or less.

[0046] The second electrode layer 30 is not divided into a plurality of electrodes and is a single electrode (hereinafter sometimes referred to as a "common electrode"). In the illustrated example, the second electrode layer (common electrode) 30 is substantially rectangular in plan view. The second electrode layer 30 can be formed from various known conductive materials, for example, it can be preferably formed from metals such as brass, copper (Cu), aluminum (Al). There is no particular limitation on the thickness of the second electrode layer 30, but it is, for example, 0.01 mm or more and 0.2 mm or less.

[0047] When a voltage is applied between the second electrode layer (common electrode) 30 and each electrode 21 of the first electrode layer 20, deformation occurs in the piezoelectric layer 10. More specifically, the region of the piezoelectric layer 10 to which the voltage is applied expands and contracts in the thickness direction. The potentials of the common electrode 30 and each electrode 21 of the first electrode layer 20 are controlled by the control device 2 (more specifically, by a signal output from the control device 2).

[0048] In the example shown here, the deformation of the piezoelectric layer 10 occurs for each region 11 (see FIGS. 3 and 4A) of the piezoelectric layer 10 corresponding to each electrode 21 of the first electrode layer 20. That is, the piezoelectric layer (vibrator layer) 10 includes a plurality of regions 11 in which the generation of vibration can be controlled independently of each other. Hereinafter, each of these regions 11 of the piezoelectric layer 10 will be referred to as a "unit region". Further, since each unit region 11 of the piezoelectric layer 10 is defined by each electrode 21 of the first electrode layer 20, hereinafter, each electrode 21 that defines (that is, corresponds to) each unit region 11 will be referred to as a "unit electrode". The shape of the unit region 11 in plan view is the same as the shape of the unit electrode 21 (substantially rectangular in the example shown). Further, hereinafter, a region 12 of the piezoelectric layer (vibrator layer) 10 that includes a plurality of unit regions 11 will be referred to as a "vibration region". The outer shape of the vibration region 12 is indicated by a chain line in FIG. 4A. In the example shown, the vibration region 12 is substantially rectangular in plan view.

[0049] The first substrate 40 is disposed on the side opposite to the piezoelectric layer 10 with respect to the first electrode layer 20 (that is, the front side of the first electrode layer 20) and supports the first electrode layer 20. The first substrate 40 has insulating properties. Further, the first substrate 40 has flexibility to such an extent that it can be deformed in accordance with the deformation of the piezoelectric layer 10.

[0050] The first substrate 40 can be a resin substrate (plastic substrate) formed from a resin material (for example, polyimide). The first substrate 40 may be a film. The thickness of the first substrate 40 is, for example, 10 μm or more and 100 μm or less.

[0051] The plurality of protrusions 50 protrude from the first substrate 40 to the side opposite to the first electrode layer 20 side. That is, the plurality of protrusions 50 are arranged on the side opposite to the piezoelectric layer 10 with respect to the first electrode layer 20. It can also be said that the first substrate 40 is arranged between the first electrode layer 20 and the plurality of protrusions 50. In the illustrated example, each of the plurality of protrusions 50 is columnar. That is, the cross-section of each protrusion is substantially the same shape over the height direction of each protrusion 50 and is substantially circular. Further, in the illustrated example, as shown in FIG. 4A, the plurality of protrusions 50 do not overlap the center of each of the plurality of unit regions 11 in plan view. Furthermore, each protrusion 50 is arranged so as to straddle the outer edge of one or two unit regions 11 in plan view, and one protrusion 50 straddles each side of each unit region 11. The protrusion 50 is preferably formed of a resin material such as polyethylene, but may also be formed of a metal material such as copper (Cu).

[0052] The fixture 60 is arranged on the side opposite to the piezoelectric layer 10 with respect to the second electrode layer (common electrode) 30. The fixture 60 is joined to the outer peripheral portion of the common electrode 30 and fixes the outer peripheral portion of the common electrode 30. Here, as shown in FIG. 5, the region 30a of the common electrode 30 that overlaps the vibration region 12 of the piezoelectric layer 10 in plan view is referred to as the "first region", and the region 30b that is located outside the first region 30a in plan view (surrounds the first region 30a in the illustrated example) is referred to as the "second region". Then, it can also be said that the fixture 60 is joined to the second region 30b of the common electrode 30 and fixes the second region 30b of the common electrode 30. In the illustrated example, the first region 30a is substantially rectangular. Also, the second region 30b is substantially in the shape of a square frame and includes four side portions 30b1, 30b2, 30b3, and 30b4.

[0053] Also, in the illustrated example, the fixture 60 has a box shape with an open top surface, and includes a bottom portion 61 and side wall portions 62 protruding from the outer peripheral portion of the bottom portion 61 toward the second electrode layer 30. The side wall portions 62 of the fixture 60 are joined to the second region 30b of the common electrode 30. Note that the fixture 60 does not necessarily have to fix all four side portions 30b1, 30b2, 30b3, and 30b4 of the second region 30b, and only some of the side portions may be fixed. For example, the fixture 60 may fix only a pair of opposing side portions (only side portions 30b1 and 30b3, or only side portions 30b2 and 30b4). Also, the fixture 60 may be omitted.

[0054] Although not shown in FIGS. 3, 4A, and 4B, wirings and the like for driving a plurality of unit electrodes 21 (that is, applying a signal (voltage) to each unit electrode 21) are provided on the main surface of the first substrate 40 on the piezoelectric layer 10 side. FIG. 6 is a diagram showing an example of an equivalent circuit of the tactile presentation element 1. In the example shown in FIG. 6, the tactile presentation element 1 includes a plurality of gate wirings GL, a plurality of source wirings SL, and a plurality of transistors Tr.

[0055] Each of the plurality of transistors Tr is provided corresponding to each unit electrode 21. The gate electrode of the transistor Tr is electrically connected to the corresponding gate wiring GL. Also, the source electrode of the transistor Tr is electrically connected to the corresponding source wiring SL, and the drain electrode of the transistor Tr is electrically connected to the corresponding unit electrode 21. Since a predetermined signal (voltage) is applied to each unit electrode 21 via the transistor Tr, deformation (expansion and contraction) of the piezoelectric layer 10 can be independently generated in a region (unit region 11) corresponding to each unit electrode 21, and vibration can be generated. The frequency of the vibration is preferably, for example, 10 Hz or more and 300 Hz or less. However, vibration stimulation may be performed by amplitude modulation (AM) of vibration in the ultrasonic range (20 kHz or more).

[0056] As described above, in the tactile presentation element 1 of the present embodiment, since the first electrode layer 20 is divided into a plurality of electrodes 21 that are electrically independent of each other, there are a plurality of vibration channels, and the fineness of the presented tactile sensation can be increased. Further, the tactile presentation element 1 of the present embodiment includes a plurality of protrusions 50, whereby problems such as the user feeling that vibration occurs at a location farther from the actual vibrating portion and the user feeling vibration in a wider range than the actual vibrating portion can be improved. Hereinafter, this point will be described by comparing it with the tactile presentation element 901 of the comparative example shown in FIGS. 7 to 9.

[0057] FIG. 7 is a cross-sectional view schematically showing the tactile presentation element 901 of the comparative example. FIGS. 8 and 9 are each a plan view schematically showing the tactile presentation element 901 and are views of the tactile presentation element 901 as seen from the front side. In FIG. 9, a part of the components (the first substrate 40) of the tactile presentation element 901 is omitted.

[0058] As shown in FIGS. 7, 8, and 9, the tactile presentation element 901 of the comparative example includes a piezoelectric layer 10, a first electrode layer 20, a second electrode layer 30, a first substrate 40, and a fixture 60, similar to the tactile presentation element 1 of the present embodiment. However, unlike the tactile presentation element 1 of the present embodiment, the tactile presentation element 901 of the comparative example does not include a plurality of protrusions 50. The tactile presentation element 901 of the comparative example was prototyped with the specifications shown in Table 1, and the presented tactile sensation was verified.

[0059]

Table 1

[0060] As shown in Table 1, the length L1 of one side of the tactile presentation element 901 in plan view was set to 7.0 mm. Similarly, the length of one side of the piezoelectric layer 10, the second electrode layer 30, the first substrate 40, and the fixture 60 in plan view was also set to 7.0 mm. The piezoelectric layer 10 was formed of PZT, and its thickness was set to 0.19 mm. The first electrode layer 20 including 25 unit electrodes 21 arranged in a 5×5 matrix was formed of copper (Cu), and its thickness was set to 100 nm. Each unit electrode 21 had a square shape with a side length L2 of 0.8 mm, and the interval S1 between adjacent unit electrodes 21 was set to 0.2 mm. The vibration region 12 of the piezoelectric layer 10 had a square shape with a side length L3 of 4.8 mm in plan view. The second electrode layer (common electrode) 30 was formed of brass, and its thickness was set to 0.13 mm.

[0061] The first substrate 40 was formed of polyimide, and its thickness was set to 50 μm. The first substrate 40 on which the first electrode layer 20 was formed was attached to the piezoelectric layer 10 with an adhesive. The fixture 60 was formed of an acrylic resin. The thickness T1 of the bottom 61 of the fixture 60 was set to 1.0 mm, and the height H1 of the side wall portion 62 was set to 2.0 mm (that is, the overall height H2 of the fixture 60 was 3.0 mm). The fixture 60 was joined to the outer peripheral portion of the second electrode layer 30.

[0062] A predetermined signal was output to each unit electrode 21 and the common electrode 30 of the prototype tactile presentation element 901 to generate vibration. The refresh rate was set to 200 Hz, and the gate open time of the region corresponding to each unit electrode 21 was set to 0.2 ms.

[0063] When the tactile sensation presented was evaluated with the finger F in contact with the surface of the first substrate 40 of the prototype tactile presentation element 901, it was possible to obtain a feeling as if the materials were different by varying the output signals. However, the vibrating part (vibration source) was felt to be present not on the surface of the finger F but about 1 cm farther from it. This is presumably because vibration propagates horizontally within the tactile presentation element 901, and a plurality of sensory receptors sense vibration of the same intensity, so that such processing and judgment (i.e., feeling that the vibration source is located farther away from the surface of the finger F) is empirically performed in the brain.

[0064] A prototype of the tactile presentation element 1 of the present embodiment was also fabricated, and the presented tactile sensation was verified. The materials and sizes (such as thickness) of the piezoelectric layer 10, the first electrode layer 20, the second electrode layer 30, the first substrate 40, and the fixture 60 were the same as those of the tactile presentation element 901 of the comparative example. The specifications of the protrusions 50 are as shown in Table 2. As shown in Table 2, a plurality of columnar protrusions 50 were formed of polyethylene, the height H of each protrusion 50 was 3.0 mm, and the diameter D1 was 0.5 mm.

[0065]

Table 2

[0066] A predetermined signal was output to each unit electrode 21 and the common electrode 30 of the fabricated tactile presentation element 1 to generate vibration. The refresh rate was 200 Hz, and the gate open time of the region corresponding to each unit electrode 21 was 0.2 ms.

[0067] When the presented tactile sensation was evaluated with the finger F in contact with the top surface of the protrusion 50 of the fabricated tactile presentation element 1, by varying the output signal, a sensation as if the materials were different could be obtained. Also, the vibration source was felt to be present on the surface of the finger F. Furthermore, compared with the case where the same signal was output in the tactile presentation element 901 of the comparative example, it was felt to be smoother, and the fineness of the tactile sensation was high. That is, vibration was felt in a narrower range than in the tactile presentation element 901 of the comparative example.

[0068] Thus, the tactile presentation element 1 of the present embodiment can accurately present tactile sensation in a minute region. The mechanism by which such an effect is obtained is presumed as follows.

[0069] FIG. 10 is a diagram for explaining the above mechanism. In FIG. 10, illustration of the first electrode layer 20, the second electrode layer 30, and the first substrate 40 is omitted.

[0070] As shown in FIG. 10, when vibration occurs, the protrusion 50 deforms, so that the contact area with the finger F changes spatially and temporally within a minute region. As a result, the intensity of the felt vibration differs considerably between adjacent sensory receptors, and it is considered that the brain processes the vibration source as being present on the surface of the finger F. For example, in the case of vision, it is known that when the difference in distance to the left and right eyes of an object is small, the object is recognized as being far away, and when the difference is large, the object is recognized as being close by brain processing. It is speculated that the mechanism is the same.

[0071] In addition, the following effects can also be obtained with the tactile presentation element 1 of the present embodiment.

[0072] In the tactile presentation element 901 of the comparative example that does not include the protrusion 50, as shown in FIG. 11 (illustration of the first electrode layer 20, the second electrode layer 30, and the first substrate 40 is omitted as in FIG. 10), if the tactile presentation element 901 is strongly pressed by the finger F, there is a risk that vibration cannot be generated due to insufficient torque.

[0073] On the other hand, in the tactile presentation element 1 of the present embodiment, since the protrusion 50 exists between the piezoelectric layer 10 and the finger F, even if the tactile presentation element 1 is strongly pressed by the finger F, as shown in FIG. 10, the protrusion 50 deforms laterally, so that sufficient vibration can be generated.

[0074] Note that the tactile presentation element 1 of the present embodiment is not typically used by tracing with the finger F. Therefore, macroscopically, the relative position between the tactile presentation element 1 and the finger F is fixed (however, microscopic fluctuations in the relative position may occur due to the minute vibration of the protrusion 50 caused by driving the tactile presentation element 1). Therefore, the area of the vibration region 12 in one tactile presentation element 1 (that is, corresponding to the fingertip abdomen fp of one finger F) is, for example, 9 cm 2Is as follows.

[0075] [Regarding the height and Young's modulus of the protrusions] From the viewpoint of suitably causing lateral deformation in the protrusion 50, it is preferable that the height H of the protrusion 50 is somewhat large. When each unit region 11 is substantially rectangular in plan view, the height H of each protrusion 50 is preferably 2 times or more, and more preferably 3 times or more, the length of the shortest side among the plurality of sides of each unit region 11 in plan view (the short side in a rectangle, each side in a square).

[0076] Also, from the viewpoint of suitably causing lateral deformation in the protrusion 50, it is preferable that the protrusion 50 is elongated, that is, the aspect ratio (ratio of height to width) of the protrusion 50 is high. When, as illustrated, the cross-section of each protrusion 50 has substantially the same shape over the height direction of each protrusion 50, expressing this in a mathematical formula, it can be said that it is preferable that the cross-sectional area A and height H of each protrusion 50 satisfy the relationship of H≧(2·A 0.5 ) / π.

[0077] Note that the shape of the cross-section of each protrusion 50 is not limited to the illustrated substantially circular shape, and may be, for example, substantially elliptical, substantially rectangular, substantially equilateral triangular, or substantially regular convex polygonal, or other figures. Also, a part of the protrusions 50 may be joined to such an extent that they can be generally said to be protrusions in terms of shape or to an extent that does not inhibit lateral vibration. For example, in order to prevent the entry of foreign matter between the protrusions 50, the top surfaces of the plurality of protrusions 50 may be joined by a very thin film (for example, a film having a thickness of 10 μm and formed from polyvinylidene chloride (PVDC), vinyl chloride resin (PVC), polymethylpentene (PMP), or polyethylene (PE)).

[0078] Also, from the viewpoint of suitably causing lateral deformation in the protrusion 50, it is preferable that the Young's modulus of each protrusion 50 is somewhat small, and specifically, it is preferably 20 GPa or less.

[0079] [Regarding the number of unit electrodes] In the above description, a configuration in which the first electrode layer 20 includes 25 unit electrodes 21 is exemplified. However, the number of unit electrodes 21 may be two or more and is not limited to 25. When the second electrode layer 30 is a common electrode (that is, when it is not divided into a plurality of unit electrodes), from the viewpoint of enhancing the fineness of touch, the plurality of unit electrodes 21 of the first electrode layer 20 are preferably nine or more unit electrodes 21 arranged in m rows and n columns (where m and n are each an integer of 3 or more) (that is, divided into nine or more parts).

[0080] [Configuration including a second substrate] Another tactile presentation element 1A according to an embodiment of the present invention will be described with reference to FIG. 12A. FIG. 12A is a cross-sectional view schematically showing the tactile presentation element 1A.

[0081] In the tactile presentation element 1 shown in FIG. 3 and the like, unlike the first electrode layer 20, the second electrode layer 30 is not directly supported by the substrate. That is, it can be said that the second electrode layer 30 is relatively thick to the extent that it can be self-supporting.

[0082] The tactile presentation element 1A shown in FIG. 12A is different from the tactile presentation element 1 in that a second substrate 70 that is disposed on the side opposite to the piezoelectric layer 10 with respect to the second electrode layer 30 and supports the second electrode layer 30 is provided.

[0083] In the tactile presentation element 1A, the second electrode layer 30 may be relatively thin to the extent that it is difficult to be self-supporting. The second electrode layer 30 can be preferably formed from a metal such as copper (Cu), nickel (Ni), silver (Ag), gold (Au), an alloy such as an Al-Nd alloy (aluminum-neodymium alloy), or a metal oxide such as indium tin oxide (ITO). The thickness of the second electrode layer 30 is, for example, 50 nm or more and 200 nm or less.

[0084] The second substrate 70 has insulation properties. Further, the second substrate 70 has flexibility to such an extent that it can be deformed in response to the deformation of the piezoelectric layer 10. The second substrate 70 can be a resin substrate (plastic substrate) formed from a resin material (for example, PET or polyimide). The second substrate 70 may be a film. The thickness of the second substrate 70 is, for example, 10 μm or more and 100 μm or less.

[0085] The fixture 60 is joined to the outer peripheral portion of the second substrate 70 and fixes the outer peripheral portion of the second substrate 70. Here, as shown in FIG. 12B, a region 70a of the second substrate 70 that overlaps with the vibration region 12 of the piezoelectric layer 10 in a plan view is referred to as the "first region", and a region 70b that is located outside the first region 70a in a plan view (surrounds the first region 70a in the illustrated example) is referred to as the "second region". Then, it can also be said that the fixture 60 is joined to the second region 70b of the second substrate 70 and fixes the second region 70b of the second substrate 70.

[0086] Regarding the tactile presentation element 1A shown in FIG. 12A and the tactile presentation element 1 shown in FIG. 3 and the like, the behavior when presenting a tactile sensation was verified by vibration simulation. For the simulation, HyperMesh manufactured by Altair was used as preprocessing software, and OptiStruct manufactured by Altair was used as a solver. During the simulation, the piezoelectric layer 10, the first electrode layer 20, the first substrate 40, the protrusion 50, and the fixture 60 were set to the specifications shown in Tables 1 and 2. The second electrode layer 30 of the tactile presentation element 1 was set to the specifications shown in Table 1. Regarding the second substrate 70 of the tactile presentation element 1A, it was assumed to be formed from a resin material and have a thickness of 0.05 mm, and the second electrode layer 30 of the tactile presentation element 1A was not considered because it is very thin (thickness 100 nm).

[0087] By simulation, the vibration intensity in the tactile presentation element 1A and the tactile presentation element 1 was evaluated. The vibration intensity was based on the magnitude M [mm] represented by the following formula. M = Δx 2 + Δy 2 + Δz 2

[0088] Here, Δx, Δy, and Δz are displacements in the x-axis, y-axis, and z-axis directions, respectively. The x-axis, y-axis, and z-axis are three mutually orthogonal axes, and the z-axis is parallel to the normal direction of the main surfaces 1a and 1b of the piezoelectric layer 10 (the height direction of the protrusion 50).

[0089] As a result of the verification by the above simulation, it was confirmed that in the tactile presentation element 1A, the magnitude directly above the vibration source (the portion where the piezoelectric layer 10 is deformed) is relatively higher than that in the tactile presentation element 1. Therefore, it can be said that the tactile presentation element 1A has higher tactile fineness than the tactile presentation element 1.

[0090] [Regarding the arrangement of protrusions, the thickness of the second substrate, etc.] In the example shown in FIG. 4A, each protrusion 50 does not overlap the center of the unit region 11 in plan view and is arranged so as to straddle the outer edge of the unit region 11, but the arrangement of the protrusions 50 is not limited to this example.

[0091] FIG. 13A shows another example of the arrangement of the protrusions 50. In the example shown in FIG. 13A, each protrusion 50 overlaps the center of the unit region 11 in plan view. Also, each protrusion 50 does not straddle the outer edge of the unit region 11 in plan view.

[0092] FIG. 13B shows still another example of the arrangement of the protrusions 50. In the example shown in FIG. 13B, each protrusion 50 does not overlap the center of the unit region 11 in plan view. Also, each protrusion 50 does not straddle the outer edge of the unit region 11 in plan view.

[0093] Instead of the arrangement shown in FIG. 4A, the arrangements shown in FIGS. 13A and 13B may be adopted. However, according to the study by the inventor of the present application, it was found that the arrangements shown in FIGS. 4A and 13B, where the protrusions 50 do not overlap the center of the unit electrode 21, are more preferable than the arrangement shown in FIG. 13A where the protrusions 50 overlap the center of the unit electrode 21. Hereinafter, this point will be explained.

[0094] Regarding the configuration including the second substrate 70 as in the tactile presentation element 1A shown in FIG. 12A, vibration simulations were performed with the arrangement of the protrusions 50 shown in FIG. 4A (hereinafter referred to as "protrusion arrangement A") and the arrangement of the protrusions 50 shown in FIG. 13A (hereinafter referred to as "protrusion arrangement B"). For the simulation, as in the verification already described, HyperMesh manufactured by Altair was used as preprocessing software, and OptiStruct manufactured by Altair was used as a solver. The piezoelectric layer 10, the first electrode layer 20, the first substrate 40, the protrusions 50, and the fixture 60 were set to the specifications shown in Tables 1 and 2 (however, the material of the fixture 60 was set to iron), and since the second electrode layer 30 was very thin (thickness 100 nm), it was not considered. For the Young's modulus, Poisson's ratio, and density of the protrusions 50, the first substrate 40, the piezoelectric layer 10, the second substrate 70, and the fixture 60, those shown in Table 3 were used.

[0095]

Table 3

[0096] The results of simulations performed by changing the thickness h [mm] and Young's modulus E [GPa] of the second substrate 70 are shown in Tables 4, 5, and 6. Also, the result screens of the simulations for some conditions are shown in FIGS. 14A, 14B, 14C, and 14D.

[0097]

Table 4

[0098]

Table 5

[0099]

Table 6

[0100] Tables 4, 5, and 6 show the magnitude and the maximum amplitude position. In the simulation, the vibration source was set at the center of the piezoelectric layer 10 in plan view. In the tables, when the maximum amplitude position is at the protrusion 50 located directly above the vibration source (for example, the four protrusions 50 located near the center in the example shown in FIG. 4A), it is denoted as "center", and when the maximum amplitude position is at a protrusion 50 shifted from directly above the vibration source, it is denoted as "peripheral". The magnitude is preferably as large as possible, and the maximum amplitude position is preferably at the center. Also, in FIGS. 14A, 14B, 14C, and 14D, the magnitude is indicated by the shade of gray, and the closer the color is to black, the larger the magnitude, and the closer the color is to white, the smaller the magnitude. FIGS. 14A and 14B are examples where the maximum amplitude position is at the center, and FIGS. 14C and 14D are examples where the maximum amplitude position is peripheral (i.e., shifted from the center).

[0101] Also, in Tables 4, 5, and 6, in addition to the thickness h and Young's modulus E of the second substrate 70, the product E·h of these is also shown. This parameter E·h is considered to be able to be used as an index representing rigidity for the following reasons.

[0102] The relationship between the load F and the displacement amount d is expressed as F = k·d in the linear range. Here, k is the spring constant, representing the rigidity including both the rigidity due to the material and the rigidity due to the shape.

[0103] On the other hand, the stress σ is expressed as σ = ε·E using the strain ε and Young's modulus E. From this equation, using the definitions of the load F, cross-sectional area S, and length L, and the stress σ and strain ε respectively, the equation F / S = (ΔL / L)·E is obtained. Further, assuming that the displacement amount d corresponds to ΔL (d = ΔL), the equation k = (E·S) / L is obtained. In this equation, it can be said that E represents the rigidity due to the material and S / L represents the rigidity due to the shape. Also, in this equation, considering that the cross-sectional area S corresponds to the product of the length L and the thickness h (i.e., S = L·h), k = E·h, so the parameter E·h can be considered to represent a certain kind of rigidity.

[0104] As can be seen from Table 4, Table 5, and Table 6, when the parameter E·h is relatively small (i.e., the rigidity is relatively low), the maximum amplitude position is at the center. When the parameter E·h is relatively large (i.e., the rigidity is relatively high), the maximum amplitude position is at the periphery. When the parameter E·h becomes extremely large (i.e., the rigidity is extremely high), the maximum amplitude position tends to be at the center. This is presumably because as the rigidity increases, the vibration is transmitted further in the lateral direction, but when the rigidity becomes extremely high, on the contrary, the vibration is less likely to be transmitted.

[0105] In the protrusion arrangement B, when the thickness of the second substrate 70 is 0.13 mm, in order for the maximum amplitude position to be at the center, as can be seen from Table 5, the Young's modulus E of the second substrate 70 must be 1 GPa or less, or about 20,000 GPa (100 times that of iron). Considering that the Young's modulus of the resin is about 2 GPa, it is not very realistic to set the Young's modulus E of the second substrate 70 in that way. In the protrusion arrangement B, when the thickness of the second substrate 70 is half of 0.13 mm, that is, 0.065 mm, since the change point of the maximum amplitude position is within the range of 2 GPa to 4 GPa, even if a material having a Young's modulus at the same level as the resin is used for the second substrate 70, the maximum amplitude position can be centered.

[0106] In the protrusion arrangement A, when the thickness of the second substrate 70 is 0.13 mm, as can be seen from Table 5 (and further from the comparison between FIGS. 14A and 14B and FIGS. 14C and 14D), when the Young's modulus E of the second substrate 70 is 15 GPa or less, the maximum amplitude position can be centered. Also, in the protrusion arrangement A, when the thickness of the second substrate 70 is 0.065 mm, as can be seen from Table 4, when the Young's modulus E of the second substrate 70 is 20 GPa or less, the maximum amplitude position can be centered.

[0107] Thus, from the perspective of widening the range of materials and thicknesses for the second substrate 70, the protrusion arrangement A is more preferable than the protrusion arrangement B. Also, in the protrusion arrangement A, when the parameter E·h is 1.95 GPa or less, that is, when the thickness h [mm] and Young's modulus E [GPa] of the second substrate 70 satisfy the relationship E·h ≤ 1.95, it is possible to center around the maximum amplitude position, and it can be said to be preferable.

[0108] It seems that it is also preferable to adopt the protrusion arrangement B because the amplitude of vibration becomes larger in the protrusion arrangement B than in the protrusion arrangement A. However, contrary to such common technical knowledge, as described above, new findings have been discovered that an arrangement where the protrusion 50 does not overlap the center of the unit region 11 is more preferable than an arrangement where the protrusion 50 overlaps the center of the unit region 11. When the plurality of protrusions 50 are arranged so as not to overlap the center of the unit region 11, it may include protrusions 50 (referred to as "first protrusions") arranged so as to straddle the outer edge of the unit region 11 in a plan view. As illustrated in FIG. 4A, when the unit region 11 is substantially rectangular in a plan view, one or more first protrusions may straddle each side of the unit region 11 in a plan view. Also, the first protrusions straddling the outer edge of one unit region 11 and the first protrusions straddling the outer edge of two or more unit regions 11 may be mixed. Further, the first protrusions and protrusions 50 (referred to as "second protrusions") arranged so as not to straddle the outer edge of the unit region 11 in a plan view may be mixed.

[0109] [Regarding the material of the fixture] The same vibration simulation was performed with the material of the fixture 60 being a resin material, and a comparison was made regarding the magnitude and the maximum amplitude position among the cases where the material of the fixture 60 is iron, the material of the fixture 60 is a resin material, and the case where the fixture 60 is not provided. For the Young's modulus, Poisson's ratio, and density of the fixture 60 formed from a resin material, those shown in Table 7 were used.

[0110] [Table 7]

[0111] The comparison results are shown in Table 8. From Table 8, the amplification effect of the magnitude when the fixture 60 is formed of iron compared to the case where the fixture 60 is not provided was about 3% at maximum. On the other hand, it was also found that there are conditions where the magnitude is higher when the fixture 60 is not provided. Also, the maximum amplitude position had almost the same tendency in all cases.

[0112]

Table 8

[0113] [Configuration in which the second electrode layer includes a plurality of unit electrodes] In the description so far, an example in which the second electrode layer 30 is a common electrode not divided into a plurality of electrodes has been given, but the configuration of the second electrode layer 30 is not limited to such an example.

[0114] With reference to FIGS. 15, 16, and 17, yet another tactile presentation element 1B according to an embodiment of the present invention will be described. FIGS. 15 and 16 are a cross-sectional view and an exploded perspective view schematically showing the tactile presentation element 1B, respectively. FIG. 17 is a plan view schematically showing the tactile presentation element 1B, and illustration of the first substrate 40 and the protrusions 50 is omitted.

[0115] In the tactile presentation element 1B shown in FIGS. 15, 16, and 17, the first electrode layer 20 includes a plurality of electrodes 22 that are electrically independent of each other, and the second electrode layer 30 also includes a plurality of electrodes 32 that are electrically independent of each other. Each of the plurality of electrodes 22 of the first electrode layer 20 is strip-shaped and extends along a certain direction. Each of the plurality of electrodes 32 of the second electrode layer 30 is strip-shaped and extends along a direction that intersects (for example, is orthogonal to) the direction in which the electrodes 22 of the first electrode layer 20 extend. Hereinafter, each electrode 22 of the first electrode layer 20 will be referred to as a "first strip electrode", and each electrode 32 of the second electrode layer 30 will be referred to as a "second strip electrode".

[0116] In the tactile presentation element 1B, a region where the first strip electrode 22 and the second strip electrode 32 intersect becomes the unit region 11. Further, in the tactile presentation element 1B, the piezoelectric layer 10 is divided into a plurality of portions (hereinafter referred to as "unit portions") 11P that are separated from each other. Each of the plurality of unit portions 11P is disposed in the intersection region (that is, the unit region 11) of the first strip electrode 22 and the second strip electrode 32.

[0117] The tactile presentation element 1B was prototyped according to the specifications shown in Table 9, and the presented tactile sensation was verified.

[0118]

Table 9

[0119] As shown in Table 9, the length L1 of one side of the tactile presentation element 1B in plan view was set to 7.0 mm. The piezoelectric layer 10 was formed of PZT, and its thickness was set to 0.19 mm. The first electrode layer 20 including the five first strip electrodes 22 was formed of copper (Cu), and its thickness was set to 100 nm. The width W1 of each first strip electrode 22 was set to 0.8 mm, and the interval S2 between adjacent first strip electrodes 22 was set to 0.2 mm. The second electrode layer 30 including the five second strip electrodes 32 was formed of copper (Cu), and its thickness was set to 100 nm. The width W2 of each second strip electrode 32 was set to 0.8 mm, and the interval S3 between adjacent second strip electrodes 32 was set to 0.2 mm. The area of the intersection region of the first strip electrode 22 and the second strip electrode 32 is 0.64 mm 2 That is. Therefore, the area of each unit portion 11 of the piezoelectric layer 10 is also 0.64 mm 2 That is.

[0120] The first substrate 40 was formed of polyimide, and its thickness was set to 50 μm. The first substrate 40 on which the first electrode layer 20 was formed was attached to the piezoelectric layer 10 with an adhesive. The second substrate 70 was formed of polyimide, and its thickness was set to 50 μm. The second substrate 70 on which the second electrode layer 30 was formed was attached to the piezoelectric layer 10 with an adhesive.

[0121] A plurality of columnar protrusions 50 were formed from polyethylene, with the height H of each protrusion 50 being 3.0 mm and the diameter D1 being 0.5 mm. The fixture 60 was formed from an acrylic resin. The thickness T1 of the bottom 61 of the fixture 60 was 1.0 mm, and the height H1 of the side wall portion 62 was 2.0 mm (i.e., the overall height H2 of the fixture 60 was 3.0 mm). The fixture 60 was joined to the outer peripheral portion of the second substrate 70.

[0122] A predetermined signal was output to each first strip electrode 22 and each second strip electrode 32 of the prototype tactile presentation element 1B, causing vibration. The refresh rate was set to 200 Hz, and the gate open time was set to 0.2 ms.

[0123] When the finger F was brought into contact with the top surface of the protrusion 50 of the prototype tactile presentation element 1B and the presented tactile sensation was evaluated, by varying the output signal, a sensation as if the materials were different could be obtained. Also, the vibration source was felt to be present on the surface of the finger F. Furthermore, compared to the case where the same signal was output in the tactile presentation element 901 of the comparative example, it was felt to be smoother and the tactile fineness was higher. That is, vibration was felt in a narrower range than in the tactile presentation element 901 of the comparative example.

[0124] Thus, like the tactile presentation element 1, the tactile presentation element 1B can also accurately present tactile sensation in a minute area. In the tactile presentation element 1B, since the piezoelectric layer 10 is divided into a plurality of unit portions 11P, vibration propagation is suppressed between the unit portions 11P. Thereby, the tactile fineness can be further increased.

[0125] Note that, different from the configurations exemplified so far, a configuration may be adopted in which the second electrode layer 30 includes a plurality of electrodes and the first electrode layer 20 includes only a single common electrode.

[0126] [Examples of Vibration Layers Other than the Piezoelectric Layer] Referring to FIGS. 18 and 19, yet another tactile presentation element 1C according to an embodiment of the present invention will be described. FIG. 18 is an exploded perspective view schematically showing the tactile presentation element 1C. FIG. 19 is a cross-sectional view schematically showing a part of the tactile presentation element 1C.

[0127] The vibrating body layer 10A included in the tactile presentation element 1C shown in FIGS. 18 and 19 includes a plurality of induction coils 13. Each induction coil 13 is disposed in a region where the first strip electrode 22 and the second strip electrode 32 intersect. That is, the vibrating body layer 10A includes an induction coil 13 for each of the plurality of unit regions 11.

[0128] Also, in the tactile presentation element 1C, instead of the fixture 60, a permanent magnet 80 is disposed on the back side of the second substrate 70 (the side opposite to the second electrode layer 30 with respect to the second substrate 70). The permanent magnet 80 is, for example, a neodymium magnet.

[0129] FIG. 20 is a perspective view showing an example of the induction coil 13. In the example shown in FIGS. 19 and 20, the induction coil 13 includes a first coil layer 13a, a second coil layer 13b, a first contact portion 13c, a second contact portion 13d, and a third contact portion 13e.

[0130] The first coil layer 13a and the second coil layer 13b are laminated in the thickness direction of the vibrating body layer 10A. With respect to the center in the thickness direction of the vibrating body layer 10A, the first coil layer 13a is disposed on the side of the first electrode layer 20, and the second coil layer 13b is disposed on the side of the second electrode layer 30. Here, an example in which the induction coil 13 includes two coil layers (the first coil layer 13a and the second coil layer 13b) is shown, but the number of coil layers is not limited to two.

[0131] The first coil layer 13a is composed of a first conductor cw1 extending in a spiral shape. There is no particular limitation on the number of turns of the first conductor cw1. A first insulating layer 14 is provided between the first coil layer 13a and the first electrode layer 20. The first coil layer 13a is electrically connected to the corresponding first strip electrode 22 via a first contact portion 13c extending from one end of the first conductor cw1 toward the first electrode layer 20 side.

[0132] The second coil layer 13b is composed of a second conductor cw2 extending in a spiral shape. There is no particular limitation on the number of turns of the second conductor cw2. A second insulating layer 15 is provided between the second coil layer 13b and the second electrode layer 30. The second coil layer 13b is electrically connected to the corresponding second strip electrode 32 via a second contact portion 13d extending from one end of the second conductor cw2 toward the second electrode layer 30 side.

[0133] A third insulating layer 16 is provided between the first coil layer 13a and the second coil layer 13b. The first coil layer 13a and the second coil layer 13b are electrically connected via a third contact portion 13e extending from the other end of the first conductor cw1 to the other end of the second conductor cw2.

[0134] When a current is applied to the induction coil 13, an electromagnetic force is generated. Due to the attractive and repulsive forces between the induction coil 13 and the permanent magnet 80, deformation can occur in each unit region 11 of the vibrating body layer 10A to generate vibration.

[0135] The tactile presentation element 1C was prototyped according to the specifications shown in Table 10, and the verification of the presented tactile sensation was performed.

[0136]

Table 10

[0137] As shown in Table 10, the length L1 of one side of the tactile presentation element 1C in plan view was set to 7.0 mm. The first electrode layer 20 including five first strip electrodes 22 was formed of copper (Cu), and its thickness was set to 100 nm. The width W1 of each first strip electrode 22 was set to 0.8 mm, and the interval S2 between adjacent first strip electrodes 22 was set to 0.2 mm. The second electrode layer 30 including five second strip electrodes 32 was formed of copper (Cu), and its thickness was set to 100 nm. The width W2 of each second strip electrode 32 was set to 0.8 mm, and the interval S3 between adjacent second strip electrodes 32 was set to 0.2 mm. The area of the intersection region between the first strip electrode 22 and the second strip electrode 32 was 0.64 mm 2 is.

[0138] The number of stacked coil layers of each induction coil 13 was set to 2. The width and thickness of the conducting wire constituting each coil layer were set to 25 μm and 200 nm, respectively. The number of turns of the conducting wire in each coil layer was set to 10.

[0139] The first substrate 40 was formed of polyimide, and its thickness was set to 50 μm. The second substrate 70 was formed of polyimide, and its thickness was set to 50 μm. The first substrate 40 on which the first electrode layer 20 was formed and the second substrate 70 on which the second electrode layer 30 was formed were joined by an adhesive so as to sandwich the vibrating body layer 10A including a plurality of induction coils 13.

[0140] A plurality of columnar protrusions 50 were formed of polyethylene, and the height H of each protrusion 50 was set to 3.0 mm and the diameter D1 was set to 0.5 mm. A neodymium magnet was used as the permanent magnet 80.

[0141] A predetermined signal was output to each first strip electrode 22 and each second strip electrode 32 of the prototype tactile presentation element 1C to generate vibration. The voltage of the signal wave was set to 1000 Vpp, the refresh rate was set to 200 Hz, and the gate open time was set to 0.2 ms.

[0142] When evaluating the tactile sensation presented with the finger F in contact with the top surface of the protrusion 50 of the prototype tactile presentation element 1C, a tactile sensation was clearly felt on the surface of the finger. Also, similar to the tactile presentation element 1 and the like, the fineness of the tactile sensation was high.

[0143] Thus, the tactile presentation element 1C provided with the vibrating body layer 10A including the induction coil 13 can also accurately present a tactile sensation in a minute area, similar to the tactile presentation element 1 provided with the vibrating body layer (piezoelectric body layer) 10 formed of a piezoelectric material.

[0144] When using the piezoelectric body layer 10 as the vibrating body layer, tactile sensing can be performed by detecting a change in the resistance value of the piezoelectric body layer 10. Even in that case, since a plurality of protrusions 50 are provided, an effect of increasing the resolution of sensing can be obtained.

[0145] When a part of the tactile presentation element 1C excluding the protrusion 50 and the permanent magnet 80 is called a "coil matrix element", the tactile presentation element 1C may be provided with a further coil matrix element instead of the permanent magnet 80. Fig. 21 shows a tactile presentation element 1C adopting such a configuration.

[0146] In the example shown in Fig. 21, the tactile presentation element 1C includes a first coil matrix element CD1 and a second coil matrix element CD2.

[0147] The first coil matrix element CD1 includes the vibrating body layer 10A, the first electrode layer 20, the second electrode layer 30, the first substrate 40, and the second substrate 70, and is the part excluding the protrusion 50 and the permanent magnet 80 in the examples shown in Figs. 18 and 19.

[0148] The second coil matrix element CD2 has a structure in which the first coil matrix element CD1 is turned upside down, and includes a coil matrix layer 90, a third electrode layer 100, a fourth electrode layer 110, a third substrate 120, and a fourth substrate 130.

[0149] The coil matrix layer 90 includes a plurality of induction coils 93. The coil matrix layer 90 has a plurality of regions in which the generation of electromagnetic force can be controlled independently of each other, and an induction coil 93 is arranged in each of those regions.

[0150] The third electrode layer 100 and the fourth electrode layer 110 are arranged to face each other with the coil matrix layer 90 therebetween. The third electrode layer 100 is arranged on the front side of the coil matrix layer 90 (the side of the first coil matrix element CD1), and the fourth electrode layer 110 is arranged on the back side of the coil matrix layer 90.

[0151] The third electrode layer 100 includes a plurality of third strip electrodes 102 extending along a certain direction. The fourth electrode layer 110 includes a plurality of fourth strip electrodes 112 extending in a direction intersecting (for example, perpendicular to) the direction in which the third strip electrodes 102 extend.

[0152] Each induction coil 93 is arranged in a region where the third strip electrode 102 and the fourth strip electrode 112 intersect. The induction coil 93 includes a first coil layer 93a, a second coil layer 93b, a first contact portion 93c, a second contact portion 93d, and a third contact portion 93e, similar to the induction coil 13 of the first coil matrix element CD1.

[0153] The first coil layer 93a and the second coil layer 93b are laminated in the thickness direction of the coil matrix layer 90. The first coil layer 93a is arranged on the front side of the second coil layer 93b.

[0154] A fourth insulating layer 94 is provided between the first coil layer 93a and the third electrode layer 100. The first coil layer 93a is electrically connected to the corresponding third strip electrode 92 through the first contact portion 93c.

[0155] A fifth insulating layer 95 is provided between the second coil layer 93b and the fourth electrode layer 110. The second coil layer 93b is electrically connected to the corresponding fourth strip electrode 112 via the second contact portion 93d.

[0156] A sixth insulating layer 96 is provided between the first coil layer 93a and the second coil layer 93b. The first coil layer 93a and the second coil layer 93b are electrically connected via the third contact portion 93e.

[0157] In the example shown in FIG. 21, by the attractive force and repulsive force between the induction coil 13 of the first coil matrix element CD1 and the induction coil 93 of the second coil matrix element CD2, deformation can occur in each unit region 11 of the vibrating body layer 10A to generate vibration.

[0158] In a configuration including a permanent magnet 80 as in the examples shown in FIGS. 18 and 19, it may be difficult to bend the tactile presentation element 1C, but in a configuration including a pair of coil matrix elements (the first coil matrix element CD1 and the second coil matrix element CD2) as in the example shown in FIG. 21, it becomes easy to bend the tactile presentation element 1C.

Industrial Applicability

[0159] Embodiments of the present invention can be widely used in a tactile presentation device that presents a sense of touch by vibration stimulation.

Explanation of Reference Numerals

[0160] 1, 1A, 1B, 1C Tactile presentation element 2 Control device 10 Vibrating body layer (piezoelectric layer) 10a First main surface 10b Second main surface 10A Vibrating body layer 11 Unit region 11P Unit portion 12 Vibration region 13, 93 Induction coil 13a, 93a First coil layer 13b, 93b Second coil layer 13c, 93c First contact portion 13d, 93d Second contact portion 13e, 93e Third contact portion 14 First insulating layer 15 Second insulating layer 16 Third insulating layer 20 First electrode layer 21 Unit electrode 22 First strip electrode 30 Second electrode layer 30a First region of the common electrode 30b Second region of the common electrode 32 Second strip electrode 40 First substrate 50 Protrusion 60 Fixture 61 Bottom 62 Side wall portion 70 Second substrate 70a First region of the second substrate 70b Second region of the second substrate 80 Permanent magnet 90 Coil matrix layer 94 Fourth insulating layer 95 Fifth insulating layer 96 Sixth insulating layer 100 Third electrode layer 102 Third strip electrode 110 Fourth electrode layer 120 Third substrate 130 Fourth substrate 100 Tactile display device 210 Personal computer (PC) 220 Head-mounted display (HMD) GL Gate wiring SL Source wiring Tr Transistor cw1 First conductor cw2 Second conductor CD1 First coil matrix element CD2 Second coil matrix element

Claims

1. A vibrating body layer, a first electrode layer and a second electrode layer disposed to face each other via the vibrating body layer, A tactile presentation element comprising: At least one of the first electrode layer and the second electrode layer includes a plurality of electrodes that are electrically independent of each other, The vibrating body layer includes a plurality of unit regions in which the generation of vibration can be independently controlled, A tactile presentation element further comprising a plurality of protrusions disposed on the side opposite to the vibrating body layer with respect to the first electrode layer.

2. The tactile presentation element according to claim 1, wherein the plurality of protrusions do not overlap the center of each of the plurality of unit regions in a plan view.

3. The tactile presentation element according to claim 1 or 2, wherein the plurality of protrusions include at least one first protrusion disposed so as to straddle the outer edge of at least one of the plurality of unit regions in a plan view.

4. The at least one first protrusion is a plurality of first protrusions, Each of the plurality of unit regions is substantially rectangular in a plan view, The tactile presentation element according to claim 3, wherein one or more of the plurality of first protrusions straddle each side of each of the plurality of unit regions in a plan view.

5. The tactile presentation element according to claim 1 or 2, further comprising a first substrate disposed between the first electrode layer and the plurality of protrusions and supporting the first electrode layer.

6. A second substrate is further provided, which is disposed on the side opposite to the piezoelectric layer with respect to the second electrode layer and supports the second electrode layer, The tactile presentation element according to claim 1 or 2, wherein the thickness h [mm] of the second substrate and the Young's modulus E [GPa] of the second substrate satisfy the relationship E·h≤1.

95.

7. Each of the plurality of unit regions is substantially rectangular in a plan view, The tactile presentation element according to claim 1 or 2, wherein the height of each of the plurality of protrusions is not less than twice the length of the shortest side among the plurality of sides of each unit region in a plan view.

8. Each of the plurality of unit regions is substantially rectangular in a plan view, The tactile presentation element according to claim 1 or 2, wherein the height of each of the plurality of protrusions is not less than three times the length of the shortest side among the plurality of sides of each unit region in a plan view.

9. Each cross-section of the plurality of protrusions has substantially the same shape over the height direction of each protrusion, The cross-sectional area A and height H of each of the plurality of protrusions satisfy the relationship H ≧ (2 · A ０．５ ) / π, the tactile presentation element according to claim 1 or 2.

10. The shape of the cross-section of each of the plurality of protrusions is a substantially circular shape, a substantially elliptical shape, a substantially rectangular shape, a substantially equilateral triangular shape, or a substantially regular convex polygonal shape, the tactile presentation element according to claim 9.

11. The Young's modulus of each of the plurality of protrusions is 20 GPa or less, the tactile presentation element according to claim 1 or 2.

12. Each of the plurality of electrodes is a plurality of unit electrodes corresponding to each of the plurality of unit regions, the tactile presentation element according to claim 1 or 2.

13. The plurality of unit electrodes are nine or more unit electrodes arranged in m rows and n columns (m and n are each an integer of 3 or more), the tactile presentation element according to claim 12.

14. Each of the first electrode layer and the second electrode layer includes the plurality of electrodes, The plurality of electrodes included in the first electrode layer are a plurality of first strip electrodes extending along a predetermined direction, The plurality of electrodes included in the second electrode layer are a plurality of second strip electrodes extending along a direction intersecting the predetermined direction, the tactile presentation element according to claim 1 or 2.

15. A second substrate disposed on the side opposite to the piezoelectric layer with respect to the second electrode layer and supporting the second electrode layer, the second substrate having a first region overlapping in a plan view with a region including the plurality of unit regions of the vibrating body layer, and a second region located outside the first region in a plan view, and A fixture joined to the second region of the second substrate and fixing the second region, The tactile presentation element according to claim 1 or 2, further comprising.

16. The first electrode layer includes the plurality of unit electrodes, The second electrode layer includes only a single common electrode, The common electrode has a first region overlapping in a plan view with a region including the plurality of unit regions of the vibrating body layer, and a second region located outside the first region in a plan view, and The tactile presentation element according to claim 12, further comprising a fixture joined to the second region of the common electrode and fixing the second region.

17. The vibrating body layer is a piezoelectric layer formed of a piezoelectric material, the tactile presentation element according to claim 1 or 2.

18. The piezoelectric layer includes a plurality of portions separated from each other, the tactile presentation element according to claim 17.

19. The vibrating body layer includes an induction coil for each of the plurality of unit regions, the tactile presentation element according to claim 1 or 2.

20. The tactile presentation element according to claim 1 or 2, a control device for controlling the tactile presentation element, and a tactile presentation device comprising the same.

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