Ultrasonic transducer and non-contact tactile display device

Abstract

To provide an ultrasonic transducer having satisfactory sound pressure characteristics and stable frequency characteristics and structured suitable for downsizing and reduction in height, and a non-contact tactile sense presentation device.SOLUTION: An ultrasonic transducer according to the present invention comprises a housing and a long ultrasonic vibrator. The housing comprises a diaphragm including a first principal surface and a second principal surface which is an opposite type of the first principal surface. The diaphragm includes an inner peripheral region, an outer peripheral region enclosing the inner peripheral region, and an intermediate region positioned between the inner peripheral region and the outer peripheral region. The intermediate region includes a plurality of openings penetrating the diaphragm, and a beam part positioned between the plurality of openings and connecting the inner peripheral region and the outer peripheral region. An internal space communicating with the external space via the plurality of through holes is formed at the side of the first principal surface of the diaphragm. The ultrasonic vibrator is joined to the inner peripheral region of the first principal surface and stored in the internal space.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ultrasonic transducer that emits ultrasonic waves and a non-contact tactile presentation device.

Background Art

[0002] Ultrasonic transducers are used as vehicle approach sensors and sensors for tracking the distance of objects. In addition, ultrasonic transducers are also used as ultrasonic wave generation sources in non-contact tactile presentation devices that use ultrasonic waves. For example, Patent Documents 1 to 3 disclose ultrasonic transducers having various configurations.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Ultrasonic transducers such as those described in Patent Documents 1 to 3 are configured to obtain excellent sound pressure characteristics by combining a substrate, a vibrator, a diaphragm, a horn, and the like. However, such a configuration requires many components and many processes for manufacturing. Furthermore, there is a possibility of loss of sound pressure due to assembly and deviation of the resonance frequency. In addition, in the case of a configuration in which the vibrator is directly attached to the housing of the ultrasonic transducer, since the rigidity of the housing is high, the resonance frequency tends to be higher than the desired frequency, and the size of the housing tends to be large. Furthermore, depending on the attachment position of the vibrator, the piezoelectric material constituting the vibrator may be depolarized due to the influence of heat treatment during mounting, etc., and there is a risk of performance degradation.

[0005] In view of the above circumstances, an object of the present invention is to provide an ultrasonic transducer and a non-contact tactile presentation device having good sound pressure characteristics and stable frequency characteristics, and having a structure suitable for miniaturization and low profile.

Means for Solving the Problems

[0006] To achieve the above object, an ultrasonic transducer according to one embodiment of the present invention includes a housing and Ultrasonic vibrator and. The housing has a first main surface and a diaphragm having a second main surface opposite to the first main surface, the diaphragm having an inner peripheral region, an outer peripheral region surrounding the inner peripheral region, and an intermediate region located between the inner peripheral region and the outer peripheral region, the intermediate region including a plurality of openings penetrating the diaphragm and beam portions located between the plurality of openings and connecting the inner peripheral region and the outer peripheral region, and an internal space communicating with the external space is formed on the first main surface side of the diaphragm by Opposite side The plurality of openings . The ultrasonic vibrator is joined to the inner peripheral region of the first main surface and is accommodated in the internal space.

[0007] The ultrasonic transducer further includes a substrate facing the first main surface, joined to the housing, and forming the internal space together with the housing, and an external terminal provided on a surface of the substrate opposite to the first main surface and electrically connected to the ultrasonic vibrator and may further include.

[0008] The ultrasonic vibrator has a Positive electrode external electrode and a negative electrode external electrode provided on a bonding surface bonded to the first main surface, and the diaphragm may further have an insulating hole provided in the inner peripheral region, penetrating the diaphragm, and separating the positive electrode external electrode and the negative electrode external electrode from the diaphragm.

[0009] The ultrasonic transducer may not include an ultrasonic resonator.

[0010] To achieve the above object, a non-contact tactile presentation device according to an aspect of the present invention includes a plurality of ultrasonic transducers. The ultrasonic transducer is a diaphragm having a first main surface and a second main surface opposite to the first main surface, and has an inner peripheral region, an outer peripheral region surrounding the inner peripheral region, and an intermediate region located between the inner peripheral region and the outer peripheral region. The intermediate region includes a plurality of openings penetrating the diaphragm and beam portions located between the plurality of openings and connecting the inner peripheral region and the outer peripheral region. A housing is provided on the first main surface side of the diaphragm to form an internal space communicating with the external space, and an ultrasonic vibrator joined to the inner peripheral region of the first main surface and housed in the internal space. Opposite side The ultrasonic transducer is a diaphragm having a first main surface and a second main surface opposite to the first main surface, and has an inner peripheral region, an outer peripheral region surrounding the inner peripheral region, and an intermediate region located between the inner peripheral region and the outer peripheral region. The intermediate region includes a plurality of openings penetrating the diaphragm and beam portions located between the plurality of openings and connecting the inner peripheral region and the outer peripheral region. A housing is provided on the first main surface side of the diaphragm to form an internal space communicating with the external space, and an ultrasonic vibrator joined to the inner peripheral region of the first main surface and housed in the internal space. The plurality of openings The ultrasonic transducer is a diaphragm having a first main surface and a second main surface opposite to the first main surface, and has an inner peripheral region, an outer peripheral region surrounding the inner peripheral region, and an intermediate region located between the inner peripheral region and the outer peripheral region. The intermediate region includes a plurality of openings penetrating the diaphragm and beam portions located between the plurality of openings and connecting the inner peripheral region and the outer peripheral region. A housing is provided on the first main surface side of the diaphragm to form an internal space communicating with the external space, and an ultrasonic vibrator joined to the inner peripheral region of the first main surface and housed in the internal space.

Advantages of the Invention

[0011] As described above, according to the present invention, it is possible to provide an ultrasonic transducer and a non-contact tactile presentation device having good sound pressure characteristics and stable frequency characteristics and a structure suitable for miniaturization and low profile.

Brief Description of the Drawings

[0012]

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Mode for Carrying Out the Invention

[0013] (First Embodiment) The ultrasonic transducer according to the first embodiment of the present invention will be described.

[0014] [Configuration of Ultrasonic Transducer] FIG. 1 is a cross-sectional view of an ultrasonic transducer 100 according to the present embodiment. As shown in the figure, the ultrasonic transducer 100 includes a housing 101, a substrate 102, an ultrasonic vibrator 103, a positive electrode wiring 104, a negative electrode wiring 105, a positive electrode external terminal 106, and a negative electrode external terminal 107.

[0015] The housing 101 constitutes the diaphragm of the ultrasonic transducer 100 and forms an internal space R together with the substrate 102. FIG. 2 is a cross-sectional view of the housing 101. As shown in the figure, the housing 101 has a diaphragm 121 and a side wall portion 122. The diaphragm 121 is flat and has a first main surface 121a and a second main surface 121b as shown in FIG. 2. The first main surface 121a and the second main surface 121b are main surfaces on the opposite sides of the diaphragm 121 from each other.

[0016] FIGS. 3 and 4 are perspective views of the housing 101. FIG. 3 is a perspective view of the housing 101 seen from the first main surface 121a side, and FIG. 4 is a perspective view of the housing 101 seen from the first main surface 121a side. FIG. 2 is a cross-sectional view taken along line A-A in FIGS. 3 and 4. FIG. 5 is a plan view of the diaphragm 121, which is a view of the diaphragm 121 seen from the second main surface 121b side. FIG. 6 is a schematic diagram showing a region of the diaphragm 121, which is a view of the diaphragm 121 seen from the second main surface 121b side.

[0017] As shown in FIG. 6, the diaphragm 121 has an inner peripheral region 131, an outer peripheral region 132, and an intermediate region 133. The inner peripheral region 131 is a region located at the central part of the diaphragm 121 and has a rectangular shape. The outer peripheral region 132 is a region located at the outer periphery of the diaphragm 121 and surrounds the inner peripheral region 131. The intermediate region 133 is a region located between the inner peripheral region 131 and the outer peripheral region 132. Note that the first main surface 121a also has the inner peripheral region 131, the outer peripheral region 132, and the intermediate region 133, similar to the second main surface 121b.

[0018] As shown in FIGS. 5 and 6, an opening 134 and a beam portion 135 are provided in the intermediate region 133. The opening 134 is a hole penetrating the diaphragm 121 as shown in FIG. 2, and a plurality of openings 134 are provided. The beam portion 135 is a portion of the intermediate region 133 where the opening 134 is not provided and is located between the openings 134. As shown in FIG. 5, the inner peripheral region 131 and the outer peripheral region 132 are separated by the opening 134 and are connected to each other by the beam portion 135.

[0019] The side wall portion 122 is a wall-like portion extending in a direction perpendicular to the first main surface 121a from the peripheral edge of the diaphragm 121. The side wall portion 122 is provided over the entire circumference of the diaphragm 121 as shown in FIG. 3 and closes the space between the diaphragm 121 and the substrate 102 as shown in FIG. 1. The material of the housing 101 is not particularly limited, but it is made of a material generally used as a diaphragm, such as aluminum, alloy, copper, etc.

[0020] The substrate 102 is joined to the housing 101 and forms an internal section together with the housing 101. As shown in FIG. 1, the substrate 102 is joined to the end of the side wall portion 122, and an internal space R surrounded by the diaphragm 121, the side wall portion 122, and the substrate 102 is formed. The substrate 102 has a first main surface 102a and a second main surface 102b. The first main surface 102a is a main surface facing the first main surface 121a of the diaphragm 121 (see FIG. 2), and the second main surface 102b is a main surface on the opposite side of the first main surface 102a.

[0021] As shown in FIG. 1, the substrate 102 includes a positive electrode internal wiring 141 and a negative electrode internal wiring 142. The positive electrode internal wiring 141 electrically connects a positive electrode wiring 104 connected to the first main surface 102a and a positive electrode external terminal 106 provided on the second main surface 102b. The negative electrode internal wiring 142 electrically connects a negative electrode wiring 105 connected to the first main surface 102a and a negative electrode external terminal 107 provided on the second main surface 102b. The positive electrode internal wiring 141 and the negative electrode internal wiring 142 are provided via through holes formed in the substrate 102.

[0022] The ultrasonic vibrator 103 generates ultrasonic vibration and vibrates the diaphragm 121. FIG. 7 is a cross-sectional view of the ultrasonic vibrator 103. As shown in the figure, the ultrasonic vibrator 103 has a single-plate structure and includes a piezoelectric layer 151, a positive electrode 152, and a negative electrode 153. The piezoelectric layer 151 is made of a piezoelectric material such as lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), or lead zirconate titanate (PbZrO 3 -PbTiO 3 ). The positive electrode 152 and the negative electrode 153 are made of a metal material such as Ni, Cu, or Ni alloy and face each other with the piezoelectric layer 151 interposed therebetween.

[0023] In the ultrasonic vibrator 103, when a voltage is applied between the positive electrode 152 and the negative electrode 153, an inverse piezoelectric effect occurs in the piezoelectric layer 151, generating ultrasonic vibration. The ultrasonic vibrator 103 is joined to the diaphragm 121 as shown in FIG. 1. The surface of the ultrasonic vibrator 103 on the negative electrode 153 side is the surface joined to the diaphragm 121, and hereinafter this surface is referred to as the joining surface 103a. By this joining, the negative electrode 153 is electrically connected to the diaphragm 121. FIG. 8 is a perspective view showing the ultrasonic vibrator 103 joined to the diaphragm 121. As shown in the figure, the ultrasonic vibrator 103 is joined to the inner peripheral region 131 of the first main surface 121a. Note that the ultrasonic vibrator 103 can be square as viewed from the joining surface 103a as shown in FIG. 8, but it may also be circular or other shapes.

[0024] The positive electrode wiring 104 (see FIG. 1) is connected to the positive electrode 152 and the positive electrode internal wiring 141, electrically connecting them. The negative electrode wiring 105 (see FIG. 1) is connected to the diaphragm 121 and the negative electrode internal wiring 142, electrically connecting the negative electrode 153 and the negative electrode internal wiring 142 via the diaphragm 121.

[0025] The positive electrode external terminal 106 is the positive electrode terminal of the ultrasonic transducer 103 and is provided on the second main surface 102b of the substrate 102. The positive electrode external terminal 106 is electrically connected to the positive electrode 152 via the positive electrode internal wiring 141 and the positive electrode wiring 104. The negative electrode external terminal 107 is the negative electrode terminal of the ultrasonic transducer 103 and is provided on the second main surface 102b of the substrate 102. The negative electrode external terminal 107 is electrically connected to the negative electrode 153 via the negative electrode internal wiring 142, the negative electrode wiring 105, the diaphragm 121.

[0026] The ultrasonic transducer 100 can be surface-mounted on the substrate to be mounted by joining the positive electrode external terminal 106 and the negative electrode external terminal 107 to the terminals provided on the surface of the substrate to be mounted (not shown).

[0027] The ultrasonic transducer 100 has the above-described configuration. As described above, the housing 101 and the substrate 102 form an internal space R (see FIG. 1), and the ultrasonic vibrator 103 is accommodated in this internal space R. The internal space R communicates with the external space S through the opening 134 provided in the diaphragm 121.

[0028] In the above description, the negative electrode 153 of the ultrasonic vibrator 103 is electrically connected to the diaphragm 121, but the positive electrode 152 may be electrically connected to the diaphragm 121. In this case, the positive electrode wiring 104 is connected to the positive electrode internal wiring 141 via the diaphragm 121, and the negative electrode wiring 105 directly connects the negative electrode 153 and the negative electrode internal wiring 142.

[0029] [Operation and Effects of Ultrasonic Transducer] In the ultrasonic transducer 100, when a voltage is applied to the positive electrode 152 and the negative electrode 153 of the ultrasonic vibrator 103 via the positive electrode external terminal 106 and the negative electrode external terminal 107, the ultrasonic vibrator 103 generates ultrasonic vibrations. As a result, the diaphragm 121 vibrates at a predetermined resonance frequency to generate ultrasonic waves. FIG. 9 is a schematic diagram showing the propagation of ultrasonic waves in the internal space R. As indicated by the arrows in the figure, the generated ultrasonic waves propagate in the internal space R and are emitted from the internal space R through the opening 134 to the external space S.

[0030] Due to the action of this opening 134, the sound pressure can be improved in the ultrasonic transducer 100. Also, the resonance frequency of the diaphragm 121 can be controlled to a desired frequency according to the position and size of the opening 134. Furthermore, since the rigidity of the housing 101 is reduced by the opening 134, the problem that the resonance frequency becomes too high due to high rigidity can be avoided, and a desired resonance frequency can be realized with a small-sized housing 101.

[0031] Also, the ultrasonic transducer 100 does not have an ultrasonic resonator such as a horn and has a structure suitable for low-profile design. Therefore, the ultrasonic transducer 100 can achieve good sound pressure characteristics and stable frequency characteristics, and has a structure suitable for miniaturization and low-profile design. Also, by configuring to directly bond the ultrasonic vibrator 103 to the housing 101, the number of parts and the assembly man-hours can be reduced, and the ultrasonic transducer 100 can be realized at low cost.

[0032] Furthermore, the ultrasonic transducer 100 is surface-mounted on the substrate to be mounted by the positive electrode external terminal 106 and the negative electrode external terminal 107 provided on the second main surface 102b of the substrate 102. The second main surface 102b is most affected by heat treatment such as reflow and soldering for the positive electrode external terminal 106 and the negative electrode external terminal 107, but since the ultrasonic vibrator 103 is separated from the second main surface 102b by the internal space R, it is possible to reduce the influence of heat treatment.

[0033] [Regarding other shapes of the opening] The shape of the opening 134 is not limited to the above. FIG. 10 is a view of the diaphragm 121 including the opening 134 having another shape as seen from the second main surface 121b side. FIG. 11 is a schematic view showing the region of this diaphragm 121. As shown in FIG. 11, the diaphragm 121 has a rectangular inner peripheral region 131, and as shown in FIG. 10, the opening 134 may have a more simplified linear shape. In this configuration, the cost can be reduced on the processed surface due to simplification. Further, since the rigidity of the diaphragm 121 is further reduced, the resonance frequency of the diaphragm 121 can be adjusted to a lower frequency range.

[0034] Further, FIG. 12 is a view of the diaphragm 121 including the opening 134 having still another shape as seen from the second main surface 121b side. FIG. 13 is a schematic view showing the region of this diaphragm 121. As shown in FIG. 13, the diaphragm 121 has a circular inner peripheral region 131, and as shown in FIG. 12, the opening 134 may have an annular shape. In this configuration, it is possible to reduce the sound pressure at the specific frequency and further improve the peak split at the resonance frequency.

[0035] (Second Embodiment) The ultrasonic transducer according to the first embodiment of the present invention will be described.

[0036] [Configuration of Ultrasonic Transducer] FIG. 14 is a cross-sectional view of the ultrasonic transducer 200 according to the present embodiment. As shown in the figure, the ultrasonic transducer 200 includes a housing 201, a substrate 202, an ultrasonic vibrator 203, a positive electrode wiring 204, a negative electrode wiring 205, a positive electrode external terminal 206, and a negative electrode external terminal 207.

[0037] The housing 201 constitutes the diaphragm of the ultrasonic transducer 200 and forms an internal space R together with the substrate 202. FIG. 15 is a cross-sectional view of the housing 201. As shown in the figure, the housing 201 has a diaphragm 221 and a side wall portion 222. The diaphragm 221 is flat and has a first main surface 221a and a second main surface 221b as shown in FIG. 15. The first main surface 221a and the second main surface 221b are main surfaces on the opposite sides of the diaphragm 221 from each other.

[0038] FIGS. 16 and 17 are perspective views of the housing 201. FIG. 16 is a perspective view of the housing 201 seen from the side of the first main surface 221a, and FIG. 17 is a perspective view of the housing 201 seen from the side of the second main surface 221b. FIG. 15 is a cross-sectional view taken along line B-B in FIGS. 16 and 17. FIG. 18 is a plan view of the diaphragm 221, which is a view of the diaphragm 221 seen from the side of the second main surface 221b. FIG. 19 is a schematic diagram showing the region of the diaphragm 221, which is a view of the diaphragm 221 seen from the side of the second main surface 221b.

[0039] As shown in FIG. 19, the diaphragm 221 has an inner peripheral region 231, an outer peripheral region 232, and an intermediate region 233. The inner peripheral region 231 is a region located at the center of the diaphragm 221 and has a rectangular shape. The outer peripheral region 232 is a region located at the outer periphery of the diaphragm 221 and surrounds the inner peripheral region 231. The intermediate region 233 is a region located between the inner peripheral region 231 and the outer peripheral region 232. Note that the first main surface 221a also has an inner peripheral region 231, an outer peripheral region 232, and an intermediate region 233, similar to the second main surface 221b.

[0040] As shown in FIGS. 18 and 19, an opening 234 and a beam portion 235 are provided in the intermediate region 233. The opening 234 is a hole that penetrates the diaphragm 221 as shown in FIG. 15, and a plurality of openings are provided. The beam portion 235 is a portion of the intermediate region 233 where the opening 234 is not provided and is located between the openings 234. As shown in FIG. 18, the inner peripheral region 231 and the outer peripheral region 232 are separated by the opening 234 and are connected to each other by the beam portion 235.

[0041] Also, as shown in FIGS. 18 and 19, insulating holes 236 are provided in the inner peripheral region 231. The insulating holes 236 are holes that penetrate the diaphragm 221 as shown in FIG. 15, and two of them are provided. The insulating holes 236 are holes for insulating the ultrasonic vibrator 203 from the diaphragm 221 as will be described later.

[0042] The side wall portion 222 is a wall-like portion that extends in a direction perpendicular to the first main surface 221a from the peripheral edge of the diaphragm 221. The side wall portion 222 is provided over the entire circumference of the diaphragm 221 as shown in FIG. 16, and closes the space between the diaphragm 221 and the substrate 202 as shown in FIG. 14. The material of the housing 201 is not particularly limited, but is made of a material generally used as a diaphragm, such as aluminum, alloy, copper, etc.

[0043] The substrate 202 is joined to the housing 201 and forms an internal section together with the housing 201. As shown in FIG. 14, the substrate 202 is joined to the end of the side wall portion 222, and an internal space R surrounded by the diaphragm 221, the side wall portion 222, and the substrate 202 is formed. The substrate 202 has a first main surface 202a and a second main surface 202b. The first main surface 202a is the main surface facing the first main surface 221a of the diaphragm 221 (see FIG. 15), and the second main surface 202b is the main surface on the opposite side of the first main surface 202a.

[0044] The substrate 202 includes a positive internal wiring 241 and a negative internal wiring 242 as shown in FIG. 14. The positive internal wiring 241 electrically connects the positive wiring 204 connected to the first main surface 202a and the positive external terminal 206 provided on the second main surface 202b. The negative internal wiring 242 electrically connects the negative wiring 205 connected to the first main surface 202a and the negative external terminal 207 provided on the second main surface 202b. The positive internal wiring 241 and the negative internal wiring 242 are provided via through holes formed in the substrate 202.

[0045] The ultrasonic vibrator 203 generates ultrasonic vibrations and vibrates the diaphragm 121. FIG. 20 is a cross-sectional view of the ultrasonic vibrator 203. As shown in the figure, the ultrasonic vibrator 203 has a laminated structure and includes a piezoelectric layer 251, a positive internal electrode 252, a negative internal electrode 253, a positive external electrode 254, and a negative external electrode 255. The piezoelectric layer 251 is made of a piezoelectric material such as lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), or lead zirconate titanate (PbZrO 3 -PbTiO 3 ). The piezoelectric layer 251 has a first main surface 251a and a second main surface 251b on the opposite side of the first main surface 251a. Also, one of the side surfaces of the piezoelectric layer 251 is defined as the first side surface 251c, and the side surface of the opposite type to the first side surface 251c is defined as the second side surface 251d.

[0046] The positive internal electrode 252 and the negative internal electrode 253 are made of a metal material such as Ni, Cu, or Ni alloy, and are alternately arranged with the piezoelectric layer 151 in between. The positive internal electrode 252 is formed such that an end face is exposed on the first side surface 251c of the piezoelectric layer 251 and is spaced apart from the second side surface 251d. The negative internal electrode 253 is formed such that an end face is exposed on the second side surface 251d of the piezoelectric layer 251 and is spaced apart from the first side surface 251c. The positive external electrode 254 is provided on the first side surface 251c and in the vicinity of the first side surface 251c on the first main surface 251a and the second main surface 251b, and is electrically connected to the positive internal electrode 252. The negative external electrode 255 is provided on the second side surface 251d and in the vicinity of the second side surface 251d on the first main surface 251a and the second main surface 251b, and is electrically connected to the negative internal electrode 253.

[0047] In the ultrasonic vibrator 203, when a voltage is applied between the positive electrode internal electrode 252 and the negative electrode internal electrode 253, the inverse piezoelectric effect occurs in the piezoelectric layer 251, generating ultrasonic vibration. The ultrasonic vibrator 203 is joined to the diaphragm 121 as shown in FIG. 14. The surface of the ultrasonic vibrator 203 on the side of the first main surface 251a is the surface joined to the diaphragm 121, and hereinafter this surface will be referred to as the joining surface 203a. FIG. 21 is a perspective view showing the ultrasonic vibrator 103 joined to the diaphragm 121. As shown in the figure, the ultrasonic vibrator 103 is joined to the inner peripheral region 131 of the first main surface 121a.

[0048] The positive electrode external electrode 254 and the negative electrode external electrode 255 are exposed on the joining surface 203a, but an insulating hole 236 is provided in the diaphragm 221, and the positive electrode external electrode 254 and the negative electrode external electrode 255 are located within the insulating hole 236 as shown in FIG. 14 and are separated from the diaphragm 221. That is, the positive electrode external electrode 254 and the negative electrode external electrode 255 are insulated from the diaphragm 221 by the insulating hole 236. Note that the ultrasonic vibrator 203 can be square as viewed from the joining surface 203a as shown in FIG. 21, but it may also be circular or other shapes.

[0049] The positive electrode wiring 204 (see FIG. 14) is connected to the positive electrode external electrode 254 and the positive electrode internal wiring 241, electrically connecting them. The negative electrode wiring 205 (see FIG. 14) is connected to the positive electrode external electrode 254 and the negative electrode internal wiring 242, electrically connecting them.

[0050] The positive electrode external terminal 206 is a terminal for the positive electrode of the ultrasonic vibrator 203 and is provided on the second main surface 202b of the substrate 202. The positive electrode external terminal 206 is electrically connected to the positive electrode external electrode 254 via the positive electrode internal wiring 241 and the positive electrode wiring 204. The negative electrode external terminal 207 is a terminal for the negative electrode of the ultrasonic vibrator 203 and is provided on the second main surface 202b of the substrate 202. The negative electrode external terminal 207 is electrically connected to the negative electrode external electrode 255 via the negative electrode internal wiring 242 and the negative electrode wiring 205.

[0051] The ultrasonic transducer 200 can be surface-mounted on a substrate to be mounted by joining the positive external terminal 206 and the negative external terminal 207 to terminals provided on the surface of a substrate to be mounted (not shown).

[0052] The ultrasonic transducer 200 has the above-described configuration. As described above, the housing 201 and the substrate 202 form an internal space R (see FIG. 14), and the ultrasonic vibrator 203 is accommodated in this internal space R. The internal space R communicates with the external space S through an opening 234 provided in the diaphragm 221.

[0053] [Operation and Effect of Ultrasonic Transducer] In the ultrasonic transducer 200, when a voltage is applied to the positive internal electrode 252 and the negative internal electrode 253 of the ultrasonic vibrator 203 via the positive external terminal 206 and the negative external terminal 207, the ultrasonic vibrator 203 generates ultrasonic vibrations. As a result, the diaphragm 221 vibrates at a predetermined resonance frequency to generate ultrasonic waves. FIG. 22 is a schematic diagram showing the propagation of ultrasonic waves in the internal space R. As indicated by the arrows in the figure, the generated ultrasonic waves propagate in the internal space R and are emitted from the internal space R through the opening 234 into the external space S.

[0054] Due to the action of this opening 234, the sound pressure can be improved in the ultrasonic transducer 200. Further, the resonance frequency of the diaphragm 221 can be controlled to a desired frequency by the position and size of the opening 234. Furthermore, since the rigidity of the housing 201 is reduced by the opening 234, the problem that the resonance frequency becomes too high due to high rigidity can be avoided, and a desired resonance frequency can be realized with a small housing 101.

[0055] Further, the ultrasonic transducer 200 does not have an ultrasonic resonator such as a horn and has a structure suitable for low-profile design. Therefore, the ultrasonic transducer 200 can achieve good sound pressure characteristics and stable frequency characteristics, and has a structure suitable for miniaturization and low-profile design. Also, by directly bonding the ultrasonic vibrator 203 to the housing 201, the number of parts and the assembly man-hours can be reduced, and the ultrasonic transducer 200 can be realized at low cost.

[0056] Furthermore, the ultrasonic transducer 200 is surface-mounted on the substrate to be mounted by a positive electrode external terminal 206 and a negative electrode external terminal 207 provided on the second main surface 202b of the substrate 202. The second main surface 202b is most affected by heat treatment such as reflow and soldering for the positive electrode external terminal 206 and the negative electrode external terminal 207. However, since the ultrasonic vibrator 203 is separated from the second main surface 202b by the internal space R, it is possible to reduce the influence of heat treatment.

[0057] Also, the ultrasonic vibrator 203 has a laminated structure (see FIG. 20). However, it can have a simple structure like a capacitor without using a technology that is difficult to form such as a through hole when forming the laminated structure. The positive electrode external electrode 254 and the negative electrode external electrode 255 are insulated by the insulating holes 236, and short circuit by the diaphragm 221 is prevented. By forming the ultrasonic vibrator 203 into a laminated structure, it is possible to further improve the sound pressure.

[0058] [Regarding other shapes of the opening] The shape of the opening 234 is not limited to the above, and like the first embodiment, it can have a simplified linear shape (see FIG. 10) or an annular shape (see FIG. 12).

[0059] [Regarding other shapes of the insulating hole] The shape of the insulating hole 236 is not limited to the above. FIGS. 23 to 25 are views of the diaphragm 221 provided with the insulating hole 236 having other shapes as seen from the second main surface 221b side. As described above, the ultrasonic transducer 203 includes the positive electrode external electrode 254 and the negative electrode external electrode 255, but these external electrodes may be provided only at the corners of the ultrasonic transducer 203. In this case, as shown in FIGS. 23 to 25, the insulating hole 236 may be provided at a position facing the corners of the ultrasonic transducer 203.

[0060] By providing the positive electrode external electrode 254 and the negative electrode external electrode 255 only at the corners of the ultrasonic transducer 203, the materials of the positive electrode external electrode 254 and the negative electrode external electrode 255 can be reduced. Further, by forming the insulating hole 236 into the shape shown in FIGS. 23 to 25, the central symmetry of the housing 201 can be improved, the influence of splitting near the resonance frequency can be avoided, and the sound pressure loss at the resonance frequency can be suppressed.

[0061] (Non-contact tactile presentation device) The ultrasonic transducers according to the first and second embodiments of the present invention can be used to configure a non-contact tactile presentation device. Specifically, a plurality of ultrasonic transducers are arranged in a planar manner, and the phases of the respective ultrasonic transducers are controlled so that ultrasonic waves reinforce each other at the position in the space where tactile sensation is to be presented, whereby tactile sensation can be presented at that position.

Explanation of reference numerals

[0062] 100, 200... Ultrasonic transducers 101, 201... Housings 102, 202... Substrates 103, 203... Ultrasonic vibrators 104, 204... Positive electrode wirings 105, 205... Negative electrode wirings 106, 206... Positive electrode external terminals 107, 207... Negative electrode external terminals 121, 221... Diaphragms 122, 221... Side wall portions 131, 231... Inner peripheral regions 132, 232... Outer peripheral region 133, 233... Intermediate region 134, 234... Opening 135, 235... Beam portion 236... Insulation hole

Claims

1. a diaphragm having a first main surface and a second main surface opposite to the first main surface, the diaphragm having an inner peripheral region, an outer peripheral region surrounding the inner peripheral region, and an intermediate region located between the inner peripheral region and the outer peripheral region, the intermediate region having a plurality of openings penetrating the diaphragm and a beam portion located between the plurality of openings and connecting the inner peripheral region and the outer peripheral region; and a housing forming an internal space on the first main surface side of the diaphragm that communicates with an external space through the plurality of openings; an ultrasonic transducer joined to the inner peripheral region of the first main surface and accommodated in the internal space; An ultrasonic transducer comprising:

2. 2. The ultrasonic transducer according to claim 1, a substrate facing the first main surface, joined to the housing, and forming the internal space together with the housing; an external terminal provided on a surface of the substrate opposite to the first main surface and electrically connected to the ultrasonic transducer; The ultrasonic transducer further comprises:

3. 3. The ultrasonic transducer according to claim 1, the ultrasonic transducer has a positive external electrode and a negative external electrode provided on a joining surface joined to the first main surface, The diaphragm further includes insulating holes provided in the inner peripheral region, penetrating the diaphragm and isolating the positive external electrode and the negative external electrode from the diaphragm. Ultrasonic transducer.

4. 4. The ultrasonic transducer according to claim 1, Does not have an ultrasonic resonator Ultrasonic transducer.

5. A plurality of ultrasonic transducers are provided, The ultrasonic transducer is a diaphragm having a first main surface and a second main surface opposite to the first main surface, the diaphragm having an inner circumferential region, an outer circumferential region surrounding the inner circumferential region, and an intermediate region located between the inner circumferential region and the outer circumferential region, the intermediate region having a plurality of openings penetrating the diaphragm and a beam portion located between the plurality of openings and connecting the inner circumferential region and the outer circumferential region, the ultrasonic transducer comprising: a housing forming an internal space on the first main surface side of the diaphragm that communicates with an external space through the plurality of openings; and an ultrasonic vibrator joined to the inner circumferential region of the first main surface and housed in the internal space. A non-contact tactile presentation device.

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