JP2019129504A - Ultrasonic wave generator, ultrasonic wave generator array and ultrasonic wave tactile feeling presentation device - Google Patents

Abstract

To provide an ultrasonic wave generator which can increase a sound pressure of ultrasonic waves to be released by itself, an ultrasonic wave generator array and an ultrasonic wave tactile feeling presentation device.SOLUTION: An ultrasonic wave generator (3) comprises: an ultrasonic wave element (30); and a horn (4). The ultrasonic wave element generates an ultrasonic wave having a predetermined frequency. The horn is disposed so as to surround a sound-release face (30s) from which the ultrasonic wave element releases ultrasonic waves. The horn has an opening end (41) forming an opening face (40s) opposed to the sound-release face of the ultrasonic wave element. A distance h between the sound-release face of the ultrasonic wave element and the opening face of the horn, an opening diameter d of the opening end, and a wavelength λ corresponding to a frequency of the ultrasonic waves satisfy a requirement represented by the following formula (1): h=(9d-4nλ)/8nλ (n is a natural number).SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to an ultrasonic generation device, an ultrasonic generation array including a plurality of ultrasonic generation devices, and an ultrasonic tactile sense presentation device including an ultrasonic generation array.

  Patent Document 1 discloses an ultrasonic transmission device including an ultrasonic microphone and a horn for adjusting the directivity of the ultrasonic microphone. In the ultrasonic wave transmission device of Patent Document 1, the distance from the end face of the internal solid material to the front surface of the bottom wall of the horn is a value obtained by multiplying a quarter of the wavelength of the ultrasonic wave transmitted from the ultrasonic microphone by an integer. The distance is set equal to Thereby, the effect of suppressing the variation in the sound pressure of the ultrasonic wave is obtained by relatively reducing the change in the sound pressure of the ultrasonic wave with respect to the variation in the distance from the end face to the front surface of the bottom wall of the horn.

JP, 2011-27428, A

  An object of the present disclosure is to provide an ultrasonic generator, an ultrasonic generator array, and an ultrasonic tactile sensation presentation device that can increase the sound pressure of emitted ultrasonic waves.

An ultrasonic generator according to an aspect of the present disclosure includes an ultrasonic element and a horn. The ultrasonic element generates an ultrasonic wave having a predetermined frequency. The horn is arranged so as to surround a sound emitting surface where the ultrasonic element emits ultrasonic waves. The horn has an open end that forms an open surface facing the sound emitting surface of the ultrasonic element. The condition that the distance h between the sound emitting surface of the ultrasonic element and the opening surface of the horn, the opening diameter d of the opening end, and the wavelength λ corresponding to the frequency of the ultrasonic wave is expressed by the following equation (1) Fulfill.
h = (9d ² -4n ² λ ² ) / 8nλ (1)
Here, n is a natural number.

  An ultrasonic generator according to another aspect of the present disclosure includes an ultrasonic element and a horn. The horn has an opening end and an inner wall that surrounds a space from the opening surface to the sound emitting surface. The difference between the straight distance, which is the distance between the sound emitting surface and the opening surface, and the reflection distance, which is the distance from the sound emitting surface to the opening end via the reflection position on the inner wall, corresponds to the ultrasonic frequency The horn is arranged so as to be an integral multiple of the wavelength to be transmitted.

  An ultrasonic generation array according to an aspect of the present disclosure includes a plurality of ultrasonic generation devices. The plurality of ultrasound generators are arranged in an array.

  According to an aspect of the present disclosure, there is provided an ultrasound tactile sense presentation device including an ultrasound generation array, and a controller that controls the ultrasound generation array so as to present the user with a tactile sensation by ultrasound generated from the ultrasound generation array. Prepare.

  According to the ultrasonic generator, the ultrasonic generator array, and the ultrasonic tactile sensation presentation device according to the present disclosure, it is possible to generate wave intensification in the horn of the ultrasonic generator and to increase the sound pressure of the emitted ultrasonic wave.

The figure which shows the structure of the ultrasonic tactile sense presentation apparatus which concerns on Embodiment 1 of this indication. The perspective view showing the composition of the ultrasonic wave generator concerning Embodiment 1 Diagram for explaining the sound pressure distribution by the ultrasonic wave generator The figure for demonstrating the conditions (1) about the horn of an ultrasonic generator The figure for demonstrating the conditions (2) about the horn of an ultrasonic generator Diagram for explaining the allowable range of setting conditions of horn The figure which shows the 1st simulation result in ultrasonic wave generator The figure which shows the 2nd simulation result in the ultrasonic wave generator The figure which shows the result of the 1st examination experiment about the ultrasonic wave generator The figure which shows the result of the 2nd examination experiment regarding the ultrasonic wave generator FIG. 6 is a view showing an example of the arrangement of an ultrasonic wave generation array according to Embodiment 2 The figure which shows the structure of the ultrasonic wave generation array which concerns on the modification 1 of Embodiment 2. The figure which shows the structure of the ultrasonic wave generation array which concerns on the modification 2 of Embodiment 2. A diagram showing a configuration example of an ultrasound generation array according to a third embodiment The figure which shows the structure of the ultrasonic wave generation array which concerns on the modification of Embodiment 3. A figure showing an example of composition of an ultrasonic wave generation array concerning Embodiment 4. The figure which shows the structure of the ultrasonic wave generation array which concerns on the modification of Embodiment 4.

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, the detailed description may be omitted if necessary. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

  In addition, applicants provide the attached drawings and the following description so that those skilled in the art can fully understand the present disclosure, and intend to limit the subject matter described in the claims by these. Absent.

(Embodiment 1)
In the first embodiment, an ultrasonic wave generator that constitutes an ultrasonic wave generation array, and an ultrasonic tactile sense presentation device that uses the ultrasonic wave generation array will be described.

1. Configuration The configuration of the ultrasonic tactile sense presentation device according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of the ultrasonic tactile sensation presentation apparatus 1.

  As shown in FIG. 1, the ultrasonic tactile sense presentation device 1 according to the present embodiment includes an ultrasonic wave generation array 10 and a controller 11. The ultrasonic tactile sense presentation device 1 is a device for presenting a tactile sensation to the user's finger 2 and hand, etc., by the sound pressure of the ultrasonic wave generated from the ultrasonic wave generation array 10. The ultrasonic tactile sensation presentation device 1 touches and operates a user in the air on an operation interface using a stereoscopic display for visually recognizing a three-dimensional object, a touch panel that can be operated without contact, or a virtual image icon, for example. Applied to give the feeling of

  The ultrasonic generation array 10 includes a plurality of ultrasonic generation devices 3 and a drive circuit 12. The ultrasonic generator 3 is a device that generates ultrasonic waves having a predetermined frequency. The frequency of the ultrasonic waves is, for example, 10 to 300 kHz.

  In the ultrasonic wave generation array 10, a plurality of ultrasonic wave generation devices 3 are arranged, for example, in a two-dimensional array on a substrate or the like. In the conventional ultrasonic wave generation array, the sound pressure of the ultrasonic wave generated from each element in the array is weak, and there is a problem that a large number of elements are required to present sufficient tactile sensation. . Therefore, in the present embodiment, the ultrasonic generator 3 is configured so as to increase the sound pressure of the ultrasonic waves generated by the individual ultrasonic generators 3. The configuration of the ultrasonic wave generator 3 according to the present embodiment will be described later.

  The drive circuit 12 of the ultrasonic generation array 10 drives each ultrasonic generation device 3 under the control of the controller 11. For example, the drive circuit 12 performs phase control to synchronize the phases of ultrasonic waves among the plurality of ultrasonic wave generators 3. The drive circuit 12 may modulate the amplitude of the ultrasonic wave by each ultrasonic wave generator 3 or set the frequency. The drive circuit 12 may be provided outside the ultrasonic wave generation array 10.

  The controller 11 controls the overall operation of the ultrasonic tactile sense presentation device 1. The controller 11 includes, for example, a CPU or MPU that realizes a predetermined function in cooperation with software. The controller 11 includes an internal memory such as a flash memory. The controller 11 reads data and programs stored in the internal memory and performs various arithmetic processing to realize various functions. For example, the controller 11 generates a control signal that causes the drive circuit 12 to modulate an ultrasonic wave based on information related to an object or the like for which a tactile sensation is to be reproduced.

  The controller 11 may be a hardware circuit such as a dedicated electronic circuit or a reconfigurable electronic circuit designed to realize a predetermined function. The controller 11 may be composed of various semiconductor integrated circuits such as a CPU, MPU, microcomputer, DSP, FPGA, ASIC. The controller 11 may be configured integrally with the drive circuit 12.

1-1. Configuration of Ultrasonic Generator The configuration of the ultrasonic generator 3 according to this embodiment will be described with reference to FIGS. FIG. 2 is a perspective view showing the configuration of the ultrasonic generator 3.

  The ultrasonic wave generator 3 according to the present embodiment comprises an ultrasonic wave element 30 and a horn 4 as shown in FIG. The ultrasonic generator 3 has a central axis 35 for ultrasonic sound emission. In the present embodiment, the direction of the central axis 35 of the ultrasonic generator 3 is the Z direction. Also, two directions orthogonal to the Z direction and orthogonal to each other are referred to as an “X direction” and a “Y direction”. Hereinafter, the + Z side from which ultrasonic waves are emitted may be referred to as the upper side, and the −Z side may be referred to as the lower side.

  The ultrasonic element 30 is an element that generates ultrasonic waves having a predetermined frequency. The ultrasonic element 30 includes, for example, a piezoelectric element, a diaphragm, and a cone (conical vibrator). The frequency of the ultrasonic wave may correspond to the natural frequency of each part of the ultrasonic element 30 or may be set by the drive circuit 12 (FIG. 1). The ultrasonic element 30 has, as an example of a sound emitting surface that emits ultrasonic waves, an upper surface 30s through which the central axis 35 passes on the XY plane, for example.

  The horn 4 is formed of, for example, a hollow member having a cylindrical shape. The horn 4 is disposed along the central axis 35 so as to surround at least the upper surface of the ultrasonic element 30. The horn 4 forms an opening 40 at the end above the ultrasonic element 30. The horn 4 may surround the lower part together with the upper surface of the ultrasonic element 30. The horn 4 is not limited to a cylindrical shape, and may have various hollow shapes.

  In the ultrasonic generator 3 of the present embodiment, the horn 4 is used in order to concentrate the sound pressure distribution of ultrasonic waves by the ultrasonic element 30 alone in the vicinity of the central axis 35. The sound pressure distribution by the ultrasonic generator 3 will be described with reference to FIGS.

  FIG. 3A shows a graph of the sound pressure distribution by the ultrasonic element 30 when the horn 4 is not present. FIG.3 (b) shows the graph of sound pressure distribution by the ultrasonic wave generator 3 of this embodiment in case the horn 4 exists. In FIGS. 3A and 3B, the vertical axis represents sound pressure, and the horizontal axis represents a radiation angle of sound pressure. The radiation angle is based on the central axis 35 of the ultrasonic generator 3 and the direction of the radiation angle 0 ° corresponds to the + Z direction. Hereinafter, the sound pressure near the radiation angle of 0 ° is referred to as "central sound pressure".

  Generally, the sound pressure distribution of the ultrasonic element 30 without the horn 4 has a main lobe and a side lobe as illustrated in FIG. The main lobe has a sound pressure peak near a radiation angle of 0 ° corresponding to the central sound pressure. The side lobe of this example has a sound pressure peak at an angular position exceeding the radiation angle of 30 °. The side lobe is formed, for example, according to the cone shape (cone angle) of the ultrasonic element 30.

  The sound pressure distribution of the general ultrasonic element 30 as in the example of FIG. 3A is dispersed in a wide angular range from the main lobe to the side lobes. For this reason, for example, when a design using a sound pressure within a radiation angle range of ± 15 ° is performed with an ultrasonic wave generating array 10 (FIG. 1) such as 50 mm square, the sound pressure distribution outside the range by the individual elements is It will be a loss.

  Therefore, in the ultrasonic wave generator 3 of the present embodiment, the central sound pressure of the ultrasonic wave emitted along the central axis 35 by collecting the sound pressure distribution on the outer side by the ultrasonic element 30 using the horn 4 Strengthen The measured value of the sound pressure distribution in an example of the ultrasonic wave generator 3 of this embodiment is illustrated to FIG. 3 (b).

  In the present embodiment, the dimensions of the horn 4 and the arrangement with respect to the ultrasonic element 30 are set in consideration of the phase of various reflected waves of the ultrasonic waves at the horn 4. Thereby, strengthening can be produced along the central axis 35 between the ultrasonic waves emitted from the horn 4, and the central sound pressure can be remarkably increased. The setting conditions of the horn 4 of the present embodiment will be described later.

  In the ultrasonic generator 3 of the present embodiment, the thickness of the horn 4 is not particularly limited. From the viewpoint of maintaining the rigidity of the horn 4 against vibration, the thickness of the horn 4 may be, for example, preferably 0.5 mm or more, and more preferably 1 mm or more.

Further, from the viewpoint of reflecting ultrasonic waves in the horn 4, the surface roughness and the material (density / sound velocity) of the inner wall are obtained. The surface roughness is, for example, Ra <80 μm. As a material, it is sufficient if the density (kg / m ³ ) × sound velocity (m / s)> 4.08 × 10 ⁵ (kg / m ² s) is satisfied. For example, resin and metal without holes can be adopted as the material of the horn 4. Preferred materials include liquid crystal polymers (LCP) for resins and aluminum for metals.

1-2. Setting Conditions of Horn The setting conditions of the horn 4 in the ultrasonic wave generator 3 of the present embodiment will be described with reference to FIGS. In this embodiment, two conditions (1) and (2) are adopted as the setting conditions for the horn 4.

  FIG. 4 is a diagram for explaining the condition (1) for the horn 4 of the ultrasonic generator 3. FIG. 5 is a diagram for explaining the condition (2) for the horn 4. 4 and 5 schematically show the ultrasonic generator 3 in the XZ cross section passing through the central axis 35. As shown in FIG.

  As shown in FIG. 4, the horn 4 in the ultrasonic generator 3 has an opening end 41 and an inner wall 42 that constitute the opening 40. The opening end 41 surrounds the periphery of the central axis 35 at the + Z side end of the horn 4 to form an opening surface 40s along the XY plane. The inner wall 42 of the horn 4 surrounds the space on the + Z side of the ultrasonic element 30.

In the ultrasonic wave generator 3 according to the present embodiment, the horn 4 and the ultrasonic wave element 30 are configured to satisfy the condition (1) represented by the following equation.
h = (9d ² -4n ² λ ² ) / 8nλ (1)

  In the above equation (1), h is the height of the tip of the horn 4, d is the aperture diameter of the aperture end 41, λ is the wavelength of the ultrasonic wave output by the ultrasonic element 30, and n is a natural number . The height h is defined by the distance between the upper surface (sound emitting surface) 30s of the ultrasonic element 30 and the opening surface 40s at the tip of the horn 4 in the Z direction. Therefore, the length L of the horn 4 in the Z direction is not less than h as shown in FIG. The wavelength λ is set based on the speed of sound assumed inside the horn 4 such as the speed of sound in air at the reference temperature. The reference temperature is included in 0 to 45 ° C., for example, and is 20 ° C., for example.

  The condition (1) is that, in the ultrasonic wave by the ultrasonic element 30, the first wave 51 going straight in the horn 4 and the second wave 52 reflected once at the inner wall 42 are emitted from the horn 4 The condition is to have the same phase on the opening surface 40s. As shown in FIG. 4, the first wave 51 passes through the straight traveling path 61 and the second wave 52 passes through the reflection path 62 within the horn 4.

  The straight traveling path 61 is a path based on a linear distance in the horn 4 along the central axis 35 of the ultrasonic wave generator 3. For example, the straight traveling path 61 extends from the sound emission position P1 at the center of the upper surface 30s of the ultrasonic element 30 to the center position P2 of the opening surface 40s. The length of the straight traveling path 61 is an example of a straight distance equal to the height h described above in the present embodiment.

  The reflection path 62 includes a straight line portion that enters the reflection position P3 on the inner wall 42 from the sound emission position P1 at an incident angle a1, and a straight line portion that emits from the reflection position P3 at a reflection angle a2 having the same magnitude as the incident angle a1. Including. In the reflection path 62, the straight line portion of the reflection angle a2 straddles the central axis 35 from the reflection position P3 and reaches the tip position P4 where the opening end 41 is located on the opening surface 40s. The length of the reflection path 62 is an example of the reflection distance in the present embodiment.

When the path difference of the straight traveling path 61 from the reflection path 62 is a natural number n times the wavelength λ, the first wave 51 and the second wave 52 can be in phase on the opening surface 40s. The length of the reflection path 62 can be expressed as h / cos θ using the angle θ between the straight portion from the sound output position P 1 and the straight travel path 61. From this, the above case can be expressed as the following equation (11).
h / cos θ−h = nλ (11)

Further, a geometrical relationship such as the following equation (12) is established among the above-mentioned angle θ, height h and opening diameter d.
h = 3 d / 2 tan θ (12)
Equation (1) is obtained by eliminating the angle θ from the above equations (11) and (12).

  According to the condition (1), by aligning the phases of the first and second waves 51 and 52 that pass through the separate paths 61 and 62 in the horn 4, a wave strengthening is generated at the opening surface 40 s and a strong sound is generated. Can form a place. In the condition (1), when h and λ are constant, the smaller the n is, the smaller the opening diameter d of the horn 4 is. From the viewpoint of miniaturization of the ultrasonic generator 3, n = 1 is preferable.

In addition to the condition (1), in the ultrasonic wave generator 3 according to the present embodiment, the horn 4 and the ultrasonic element 30 are configured to satisfy the condition (2) represented by the following equation.
h = λ (2m + 1) /4-0.3d (2)

  In the above equation (2), m is a natural number. Further, the second term on the right side of the above equation (2) indicates a correction amount for correcting the opening end. The condition (2) will be described with reference to FIG.

  The condition (2) is a condition for generating a standing wave 50 by resonance in the horn 4 as shown in FIG. The standing wave 50 is formed by superposition of an ultrasonic wave emitted from the ultrasonic element 30 in the + Z direction and a reflected wave that is reflected at the free end in the vicinity of the opening 40 of the horn 4 to the −Z side. A node of the standing wave 50 is located on the upper surface 30 s of the ultrasonic element 30.

  According to the condition (2), the height h of the tip of the horn 4 is set to be smaller by the correction amount of the opening end correction from an odd multiple of λ / 4, so that the antinode of the standing wave 50 is on the + Z side of the opening 40. The standing wave 50 can be formed so as to be located in the vicinity of. Thereby, the sound field of ultrasonic waves can be strengthened in the vicinity of the opening surface 40 s of the horn 4.

  According to the condition (2), h (or d) can be reduced as m is smaller. From the viewpoint of miniaturization of the ultrasonic generator 3, m may be 5 or less, for example.

  The setting of the height h and the aperture diameter d of the tip of the horn 4 according to the above two conditions (1) and (2) may be performed for a unique frequency among the frequencies of ultrasonic waves that can be output from the ultrasonic element 30 . For example, when the frequency of the ultrasonic wave by the ultrasonic wave generator 3 is 43.5 kHz, the wavelength λ of the ultrasonic wave is 7.91 mm under the environment of a temperature of 21 ° C. In this case, if n = 1 and m = 5 in equations (1) and (2), h = 18.2 mm and d = 12.5 mm are derived as ideal setting values.

  In the above example, the inner wall 42 of the horn 4 is not inclined. Further, in the design in which the horn 4 is installed on a substrate or the like to which the ultrasonic element 30 having a height of 7.2 mm is fixed, the length L of the horn 4 is about 25.4 mm.

  According to the above ideal setting value, in the ultrasonic wave generator 3 with the horn 4, an effect of increasing the central sound pressure at a radiation angle of 0 ° to 1.8 times that in the absence of the horn 4 was obtained. (See Figure 3). Such an effect of increasing the sound pressure can be expected from, for example, a sound pressure distribution within a radiation angle of ± 30 °, and a sound pressure increase of 1.6 times can be obtained even within a radiation angle of ± 15 °.

The setting conditions of the horn 4 of the present embodiment do not necessarily exactly coincide with the expressions (1) and (2) as in the above ideal case, and an allowable error can be set appropriately from various viewpoints. It is. For example, as shown in the following equation (3), the allowable range of the deviation of the height h can be considered using the coefficient k.
h = k (9 d ^2-4 n ² λ ² ) / 8 n λ
= K x {λ (2m + 1) /4-0.3d} (3)

  An allowable range of the deviation of the height h in the setting conditions (1) and (2) of the horn 4 will be described with reference to FIGS. 6 (a) and 6 (b). FIG. 6A is a chart illustrating an allowable range based on the effectiveness of the effect of increasing the central sound pressure. FIG. 6B is a chart illustrating an allowable range based on the use temperature.

  In FIG. 6 (a), with respect to the effect of increasing the central sound pressure by the horn 4 according to the setting conditions (1) and (2), the viewpoint of maintaining the effectiveness at which the above ideal setting value is 100% at maximum is 80% or more. The calculated value and the actual measurement value of the deviation of the height h are shown. The calculated value of the said deviation was computed by the following thinking.

  That is, as for the condition (1), when the height h deviates, the path difference between the straight traveling path 61 and the reflection path 62 (FIG. 4) changes, and the phase difference between the first and second waves 51 and 52 Will occur. Therefore, the calculated value of the deviation of the height h was calculated from the idea that the effectiveness of the sound pressure increasing effect is from 100% when the phase difference is 0 to 0% when the phase difference is π / 2. A sine curve was used for the calculation during the phase difference of 0 to π / 2.

  As to condition (2), when m = 5 as described above, standing wave 50 (FIG. 5) has six antinodes, and if the height h is corrected for the opening end, it becomes 11/4 λ . In this case, it is considered that when the height h deviates by 1 / 11λ, the vicinity of the opening 40 becomes a node and the central sound pressure decreases (that is, the effectiveness is 0%). FIG. 6A shows a calculation result based on the concept of the condition (1).

  According to the above concept, as shown in FIG. 6A, the measured value corresponding to the effectiveness is obtained in good agreement with the actually measured value for the effect of increasing the central sound pressure. According to FIG. 6 (a), for example, the allowable error of the height h for obtaining the effect of increasing the central sound pressure with an effectiveness of 90% or more is about ± 2.5%, and k = 1 ± 0.025. Become.

  Further, the tolerance such as the height h may be set from the viewpoint of the temperature when the ultrasonic wave generator 3 is used. Since the sound velocity changes when the temperature of the air changes, the wavelength λ of the ultrasonic wave output from the ultrasonic generator 3 varies according to the operating temperature even if the frequency of the ultrasonic wave is constant.

  In FIG. 6 (b), the influence of the deviation of the height h at various use temperatures assumed with reference to the height h derived from the equations (1) and (2) at 20 ° C., and the above sound It shows the decreasing rate of the pressure increase effect.

  As a working temperature of the ultrasonic wave generator 3 and the ultrasonic wave generation array 10, for example, 0 to 40 ° C., preferably 10 to 30 ° C., and more preferably 15 to 25 ° C. are assumed. For example, when the use temperature changes at 0 to 40 ° C., as shown in FIG. 6B, the ideal height h varies in the range of −4.9% to + 5.2% for each use temperature. Become. From such a viewpoint, for example, ± 5% from an ideal set value of the height h of 20 ° C. as a reference is set as an allowable range of deviation of the height h (ie, k = 1 ± 0.05), and ultrasonic waves are generated. The device 3 may be manufactured.

  When the horn 4 is designed according to the ultrasonic element 30 used for the ultrasonic wave generation array 10, the aperture diameter d is a side lobe of the ultrasonic element 30 in the range of the radiation angle collected by the horn 4 (see FIG. It may be determined to include 3). (FIG. 4) is designed to be equal to or greater than the radiation angle of the side lobes, for example, to enhance the sound collection effect. Further, in determining the aperture diameter d, the number of elements and the area that are allowed in manufacturing the ultrasonic generation array 10 may be taken into consideration.

  In the above description, the case where the inner wall 42 of the horn 4 is not inclined with respect to the central axis 35 has been described, but the inner wall 42 may have an inclination. In this case, considering the reflection position P3 of the second wave 52 reflected on the inner wall 42 and the reflection path 62, the horn so that the difference between the straight path 61 and the reflection path 62 is n times the wavelength λ. 4 is set (condition (1)). As a result, as in the case described above, the first and second waves 51 and 52 can have the same phase at the opening surface 40 s to generate a reinforcement.

2. Operation Operations of the ultrasonic tactile sensation presentation apparatus 1 and the ultrasonic generation apparatus 3 configured as described above will be described below.

  The ultrasonic tactile sensation presentation apparatus 1 (FIG. 1) of the present embodiment controls the ultrasonic generation array 10 by the controller 11 in a state where, for example, a three-dimensional object or an operation interface is set in the air. The controller 11 generates a control signal for reproducing the tactile sensation according to the set position and shape of the object or the like, and outputs the control signal to the drive circuit 12 of the ultrasonic wave generation array 10. The drive circuit 12 drives each ultrasonic generator 3 based on the control signal. Thus, it is possible to present the user with a tactile sensation of touching or operating an object or the like by the sound pressure of the ultrasonic wave.

  According to the ultrasonic generator 3 of this embodiment, by using the horn 4 that satisfies the above setting conditions, the ultrasonic sound pressure for presenting the tactile sensation is strengthened and presented by the ultrasonic tactile sensation presentation apparatus 1. The touch can be strengthened. Further, by increasing the sound pressure by the individual ultrasonic generators 3, the number of ultrasonic generators 3 included in the ultrasonic generator array 10 can be reduced.

2-1. About simulation and examination experiment The inventor of the present application conducted simulation by numerical analysis and examination experiment to confirm the effect of the ultrasonic wave generator 3 of the present embodiment. Analysis simulation and examination experiments by the inventor of the present application will be described with reference to FIGS.

  FIG. 7 shows a first simulation result in the analysis simulation of the ultrasonic generator 3. FIG. 8 shows a second simulation result. FIG. 9 shows the result of the first examination experiment on the ultrasonic generator 3. FIG. 10 shows the results of the second examination experiment.

  In the analysis simulations of FIGS. 7 and 8, the sound pressure in the space around the horn 4 of various dimensions was numerically calculated by changing dimensions such as the length L of the horn 4 in the ultrasonic generator 3. FIGS. 7A to 7B show the + X side of the central axis 35 of the ultrasonic wave generator 3.

  FIG. 7A shows a first simulation result when the above condition (1) is satisfied. FIG. 7B shows a first simulation result when the condition (1) is not satisfied.

  When the condition (1) is satisfied, the reinforcement between the first and second waves 51 and 52 (FIG. 4) described above occurs near the opening surface 40 s serving as the outlet on the + Z side of the horn 4. Thereby, as shown in FIG. 7A, a strong sound pressure wave is output from the outlet of the horn 4 on the extension line in the + Z direction.

  On the other hand, when the in-phase condition (1) is not satisfied, the wave strengthening as described above does not occur. For this reason, as shown in FIG. 7B, the wave exiting the horn 4 spreads outward from the horn 4 such as the + X side. Therefore, the sound pressure of the ultrasonic wave is dispersed as it moves away from the horn 4 in the + Z direction.

  FIGS. 8A and 8B show the second simulation results in the case where the condition (1) is satisfied and in the case where the condition (1) is not satisfied. FIG. 8A shows the simulation result when the phase of the third wave 53 is opposite to that of the first and second waves 51 and 52 at the opening surface 40s when the condition (1) is satisfied. It shows. The third wave 53 is a wave that reaches the center of the opening surface 40 s after being reflected inside the horn 4 in the ultrasonic wave from the ultrasonic element 30.

  In the above case, due to the superposition of the third wave 53, the sound pressure is not increased near the center of the opening surface 40s of the horn 4 as shown in FIG. However, since the reinforcement between the first and second waves 51 and 52 is generated, a strong sound pressure wave is output from the outlet of the horn 4 on the extension line in the + Z direction. As described above, according to the in-phase condition (1), it was confirmed that a strong sound pressure wave could be output in the direction of the central axis 35 of the horn 4.

  In the first examination experiment (FIG. 9), the sound pressure was measured while changing the length L and opening diameter d of the horn 4. At this time, the height h was changed without changing the height of the ultrasonic element 30. The temperature at the time of measurement was 21 ° C., and the driving conditions of the ultrasonic element 30 were 43.5 kHz and 25 Vp-p.

  In the first examination experiment, the sound pressure was measured while changing the length L every 0.1 mm. As a measured value of the sound pressure, each central sound pressure (that is, sound pressure at a radiation angle of 0 °) was measured using an average value between five elements. Normalization was performed with the central sound pressure in the absence of the horn 4 as 1. When d = 12.55 and 12.75, instead of actual measurement, interpolation is performed using an average value of measured values when d = 12 and 12.5, and an average value of d = 12.5 and 13, respectively. did.

  FIG. 9 shows the distribution (contour lines) of the sound pressure of the measurement result in the two-dimensional coordinates (d, h) (the same applies to FIG. 10). Moreover, in FIG. 9, the area which satisfy | fills setting conditions (1) and (2) of the above-mentioned horn 4 is shown. According to the first examination experiment, as shown in FIG. 9, it was confirmed that stronger sound pressure can be obtained when the condition (1) is satisfied and the condition (2) is satisfied.

  In the second study experiment, the same sound pressure measurement as in the first study experiment was performed by changing the length L every 0.5 mm. For the unmeasured region, the experimental result of FIG. 10 was obtained by interpolating on the assumption that the increase / decrease in the sound pressure is exponential. As shown in FIG. 10, according to the second examination experiment, as in the first examination experiment, the central sound is generated according to the setting conditions (1) and (2) of the horn 4 in the ultrasonic wave generator 3 of the present embodiment. It could be confirmed that the pressure could be strengthened.

3. As described above, the ultrasonic wave generator 3 according to the present embodiment includes the ultrasonic wave element 30 and the horn 4. The ultrasonic element 30 generates an ultrasonic wave having a predetermined frequency. The horn 4 is disposed so as to surround the sound emitting surface (upper surface 30s) from which the ultrasonic element 30 emits ultrasonic waves. The horn 4 has an opening end 41 that forms an opening surface 40 s that faces the sound emitting surface of the ultrasonic element 30. The distance h between the sound emitting surface of the ultrasonic element 30 and the opening surface 40 s of the horn 4, the opening diameter d of the opening end 41, and the wavelength λ corresponding to the frequency of the ultrasonic wave are expressed by the above equation (1). Meet the requirements (see FIG. 4).

  According to the ultrasonic generator 3 described above, the opening of the horn 4 of the ultrasonic generator 3 is intensified by aligning the phases of the first and second waves 51 and 52 on the opening surface 40 s of the horn 4. The sound pressure of the ultrasonic wave emitted from can be strengthened.

  In the ultrasonic wave generator 3 in the present embodiment, the distance h, the aperture diameter d, and the wavelength λ satisfy the condition represented by the above-mentioned equation (2) (see FIG. 5). Thereby, the standing wave 50 can be generated in the horn 4 and the sound field of the ultrasonic wave can be strengthened.

  In the ultrasonic generator 3 in the present embodiment, the conditions represented by the expressions (1) and (2) are satisfied within a range of ± 5% of the magnitude of the distance h. Thereby, the effect of increasing the sound pressure sufficiently in practical use can be obtained.

  In the present embodiment, the ultrasonic generator 3 includes an ultrasonic element 30 and a horn 4 having an open end 41 and an inner wall 42. The inner wall 42 of the horn 4 surrounds the space from the opening surface 40s to the sound emitting surface. The difference between the rectilinear distance that is the distance between the sound emitting surface and the opening surface 40s and the reflection distance that is the distance from the sound emitting surface to the opening end 41 via the reflection position P3 on the inner wall 42 is an ultrasonic wave. The horn 4 is arranged so as to be an integral multiple of the wavelength λ corresponding to the frequency of. The above-described ultrasonic wave generator 3 can also cause the first and second waves 51 and 52 to strengthen each other, and the sound pressure of the ultrasonic wave emitted from the ultrasonic wave generator 3 can be strengthened.

  The ultrasonic wave generation array 10 in this embodiment includes a plurality of ultrasonic wave generation devices 3. The plurality of ultrasonic wave generators 3 are arranged in an array. According to the ultrasonic wave generation array 10 of the present embodiment, the ultrasonic wave generation device 3 can intensify the sound pressure of the emitted ultrasonic wave.

  The ultrasonic tactile sensation presentation apparatus 1 according to the present embodiment includes an ultrasonic generation array 10 and a controller 11. The controller 11 controls the ultrasonic generation array 10 so as to present a tactile sensation to the user by the ultrasonic waves generated from the ultrasonic generation array 10. According to the ultrasonic tactile sensation presentation apparatus 1 of the present embodiment, the sound pressure of ultrasonic waves for presenting a tactile sensation can be increased by the plurality of ultrasonic generation apparatuses 3 in the ultrasonic generation array 10.

Second Embodiment
In the second embodiment, an ultrasonic wave generation array in which horns of a plurality of ultrasonic wave generation devices are integrally formed will be described with reference to FIGS.

  FIG. 11 is a diagram illustrating a configuration example of an ultrasonic wave generation array 10A according to the second embodiment. In the ultrasonic generation array 10A according to the present embodiment, a plurality of horn portions 4a are integrally formed instead of the plurality of horns 4 in the same configuration as the ultrasonic generation array 10 (FIG. 1) of the first embodiment. An integrated horn 4A is provided. Each horn portion 4a of the integrated horn 4A is set to various dimensions so as to satisfy the setting conditions (1) and (2) corresponding to the individual ultrasonic elements 30 in the same manner as the horn 4 of the first embodiment. Be done.

  When elements of the same design are used as the plurality of ultrasonic elements 30 in the ultrasonic wave generation array 10A, the respective wavelengths are substantially constant, and setting values such as the height h and the aperture diameter d become constant values in the array. Can be considered. In this case, the integrated horn 4A can be designed with a set value common to the plurality of horns 4a, and the manufacturing of the ultrasonic wave generator 3 can be facilitated.

  11A and 11B are plan views of the ultrasonic wave generation array 10A before and after the integrated horn 4A is attached. As shown in FIG. 11A, the plurality of ultrasonic elements 30 are arranged side by side on, for example, a planar substrate 13. As shown in FIG. 11B, the integrated horn 4A is mounted on the substrate 13 so that the horns 4a face the ultrasonic elements 30, respectively.

  According to the ultrasonic generation array 10A of the present embodiment, by integrating the horn part 4a for each ultrasonic element 30 into the integrated horn 4A, the wall thickness for each horn part 4a can be formed thin, and a plurality of horn parts 4a are formed. Occupied area can be reduced.

  The ultrasonic generation array 10A of the present embodiment is not limited to the configuration example of FIG. For example, in the ultrasonic wave generation array 10A, all the horns 4a may be integrated, or some horns 4a may be integrated. Modifications 1 and 2 of the ultrasonic wave generation array 10A according to the present embodiment will be described with reference to FIGS.

  FIG. 12 shows a configuration of an ultrasonic wave generation array 10B according to the first modification of the second embodiment. Hereinafter, the direction of the central axis 35 of the ultrasonic generator 3 located at the center of the ultrasonic generation array 10B is defined as the Z direction (see FIG. 12B).

  FIG. 12A shows a plan view of the ultrasonic wave generation array 10B viewed from the Z direction. FIG. 12B shows a side view of the ultrasonic wave generation array 10B viewed from the Y direction.

  The ultrasonic generation array 10B of the present modification includes an integrated horn 4B having a bowl shape as shown in FIGS. 12A and 12B instead of the integrated horn 4A in the configuration example of FIG. In this modification, the integrated horn 4B is formed so that all the horn parts 4a of the ultrasonic wave generation array 10B are arranged on the spherical bottom of the bowl shape of the integrated horn 4B.

  FIG. 13 shows a configuration of an ultrasonic wave generation array 10C according to the second modification of the second embodiment. FIG. 13A shows a plan view of the ultrasonic wave generation array 10C. FIG. 13B shows a side view of the ultrasonic wave generation array 10C.

  As shown in FIGS. 13A and 13B, an ultrasonic wave generation array 10C according to this modification includes a plurality of integrated horns 4C arranged in the X direction. In addition, the ultrasonic elements 30 in the ultrasonic wave generation array 10C are divided into a plurality of substrates 14 aligned in the X direction. The longitudinal direction of each substrate 14 is in the Y direction.

  In this modification, the plurality of integrated horns 4C are arranged on the substrate 14 as shown in FIG. 13A, and the horn portions 4a of the plurality of ultrasonic elements 30 for each substrate 14 are integrated. For example, as shown in FIG. 13B, the ultrasonic wave generation array 10C is formed in a boat shape by arranging a plurality of substrates 14 inclined to each other.

  As described above, in the ultrasonic wave generation arrays 10A to 10C in the present embodiment, the horns 4a of a part or all of the ultrasonic wave generation devices 3 among the plurality of ultrasonic wave generation devices 3 are integrally formed. . Thereby, the ultrasonic wave generation arrays 10A to 10C can be miniaturized.

(Embodiment 3)
In the third embodiment, an ultrasonic wave generation array having focused positions of ultrasonic waves from a plurality of ultrasonic wave generation devices will be described with reference to FIGS.

  FIG. 14 shows a configuration example of the ultrasonic wave generation array 10B ′ according to the third embodiment. 14A and 14B show a plan view and a side view of the ultrasonic wave generation array 10B ', respectively.

  In the ultrasonic wave generation array 10B ′ shown in FIG. 14, in the same configuration as FIG. 12, the central axes 35 of all the ultrasonic wave generation devices 3 are integrated such that they intersect at one intersection point P10 in the + Z side space Each horn 4a is formed in the horn 4B. The intersection P10 is an example of a focusing position where the sound pressure of ultrasonic waves is concentrated.

  Since the sound pressure distribution of each ultrasonic element 30 has the largest central sound pressure in the direction of the central axis 35 at a radiation angle of 0 °, in the present embodiment, the central axes 35 of the plurality of ultrasonic wave generating devices 3 Install to match. Specifically, the intersection P10 of the central axis 35 of the ultrasonic generator 3 is formed at a desired focusing position such as in the vicinity of the ultrasonic generator array 10B '.

  According to the ultrasonic generation array 10B ′ of the present embodiment, by using the sound pressure at the intersection P10 where the largest central sound pressure is concentrated in each of the ultrasonic generators 3, the sound pressure as an output of tactile sensation presentation or the like is used. Or the number of ultrasonic elements 30 can be reduced.

  There may be a plurality of intersection points P10 in the ultrasonic wave generation array 10B 'as described above. The present modification will be described with reference to FIG.

  FIG. 15 shows a configuration of an ultrasonic wave generation array 10 </ b> C ′ according to a modification of the third embodiment. FIGS. 15A and 15B are a plan view and a side view of the ultrasonic wave generation array 10 </ b> C ′, respectively.

  The ultrasonic wave generation array 10C ′ shown in FIG. 15 has the same configuration as that of FIG. 13 except that the central axes 35 of the ultrasonic wave generation devices 3 in a pair arranged in the X direction on separate substrates 14 each have one intersection point P10. The inclination of the substrate 14 is adjusted so as to intersect. As a result, the ultrasonic wave generation array 10 </ b> C ′ of this modification has a plurality of intersection points P <b> 10 arranged in the Y direction as shown in FIG.

  As described above, in the ultrasonic wave generation arrays 10B 'and 10C' in the present embodiment, the plurality of ultrasonic wave generation devices 3 each have the central axis 35 for emitting ultrasonic waves. The central axis 35 of some or all of the plurality of ultrasonic generators 3 has an intersection P10 where they intersect each other. As a result, by concentrating the sound pressure from the plurality of ultrasonic generators 3 at the intersection P10, the sound pressure of the output of the ultrasonic generator array 10C ′ can be increased, or the size can be reduced by reducing the number of elements. it can.

  In addition, the ultrasonic wave generation arrays 10B 'and 10C' concentrate the sound pressure at points other than the intersection point P10 by controlling the phases of the ultrasonic waves from the plural ultrasonic wave generation devices 3 with the drive circuit 12 (FIG. 1) or the like. You can also

(Embodiment 4)
In the fourth embodiment, an ultrasound generation array in which the distances from the plurality of ultrasound generation devices to the focusing position are equalized will be described with reference to FIGS.

  Fig. 16 is a side view showing a configuration example of an ultrasonic wave generation array 10B "according to the fourth embodiment. In the ultrasonic wave generation array 10B" shown in FIG. The integrated horn 4B is formed so that the distances D1, D2, D3 from the device 3 to the intersection P10 are equal. The distances D1, D2, and D3 to the intersection P10 for each ultrasonic generator 3 are set with reference to the sound emission surface of each ultrasonic generator 3, for example.

  In the present embodiment, the drive circuit 12 (see FIG. 1) of the ultrasonic wave generation array 10B ′ ′ simultaneously outputs a signal common to, for example, all the ultrasonic wave generation devices 3 to drive the ultrasonic wave generation device 3. Thus, the ultrasonic waves from the respective ultrasonic generators 3 have the same phase at the intersection point P10, and it is possible to obtain a sound pressure that strengthens at the intersection point P10.

  For example, in the ultrasonic tactile sense presentation device 1, in order to increase the sound pressure of tactile sense presentation, it is conceivable to perform phase control to match the phases of ultrasonic waves from the plurality of ultrasonic wave generation devices 3 by the drive circuit 12. According to the ultrasonic wave generation array 10B ″ of the present embodiment, the distances D1, D2, and D3 to the intersection P10 for each ultrasonic wave generator 3 are uniform, so that the drive circuit can be used without using a complicated phase control circuit configuration. 12 can be configured.

  The distances D1, D2, and D3 to the intersection P10 in the ultrasonic wave generation array 10B ″ may be set so as to be shifted by the ultrasonic wavelength. A modification of the fourth embodiment will be described with reference to FIG. 17 shows a configuration of an ultrasonic wave generation array 10C ′ according to a modification of the fourth embodiment.

  The ultrasonic generation array 10C ″ shown in FIG. 17 has the same configuration as that of FIG. 15 and sets the distances D1, D2, and D3 to the intersection P10 in the set of the ultrasonic generators 3 that share the intersection P10. The position of the substrate 14 is adjusted, and the difference between the distances D1, D2 and D3 is set to be an integral multiple of the wavelength λ of the ultrasonic wave, also in this case, at the intersection point P10 as described above. Sound waves that are intensified can be obtained by ultrasound waves of the same phase.

  As described above, in the present embodiment, the ultrasonic wave generation arrays 10B ′ ′ and 10C ′ ′ include the drive circuit 12 (FIG. 1) that drives the plurality of ultrasonic wave generation devices 3. In order to make the difference between the distances D1 to D3 from each ultrasonic generator 3 to the intersection P10 an integer multiple of the wavelength λ between the sets of ultrasonic generators 3 at which the respective central axes 35 intersect at the intersection P10, A set of sound wave generators 3 is arranged. The drive circuit 12 drives the set of ultrasonic wave generators 3 simultaneously. Thereby, the sound pressure at the intersection P10 can be increased without performing complicated phase control.

(Other embodiments)
As described above, Embodiments 1 to 4 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and is also applicable to embodiments in which changes, substitutions, additions, omissions, and the like are made as appropriate. Moreover, it is also possible to combine each component demonstrated by each said embodiment into a new embodiment.

  As described above, the embodiments have been described as examples of the technology in the present disclosure. For that purpose, the attached drawings and the detailed description are provided.

  Therefore, among the components described in the attached drawings and the detailed description, not only components essential for solving the problem but also components not essential for solving the problem in order to exemplify the above-mentioned technology. May also be included. Therefore, the fact that those non-essential components are described in the attached drawings and the detailed description should not immediately mean that those non-essential components are essential.

  Moreover, since the above-mentioned embodiment is for illustrating the technique in this indication, various change, substitution, addition, omission, etc. can be performed within the range of a claim or its equivalent.

Reference Signs List 1 ultrasonic tactile sense presentation device 10, 10A to 10C ′ ′ ultrasonic wave generation array 11 controller 3 ultrasonic wave generation device 30 ultrasonic wave element 35 central axis 4 horn 40 opening 41 opening end 42 inner wall

Claims (9)

An ultrasonic element for generating an ultrasonic wave having a predetermined frequency;
A horn disposed so as to surround the sound emitting surface from which the ultrasonic element emits the ultrasonic wave;
The horn has an open end forming an open surface facing the sound emitting surface of the ultrasonic element,
The distance h between the sound emitting surface of the ultrasonic element and the opening surface of the horn, the opening diameter d of the opening end, and the wavelength λ corresponding to the frequency of the ultrasonic wave are represented by the following equation (1) Meet the conditions
h = (9d ² -4n ² λ ² ) / 8nλ (1)
Here, n is a natural number. The distance h, the aperture diameter d, and the wavelength λ satisfy a condition represented by the following formula (2):
h = λ (2m + 1) /4-0.3d (2)
The ultrasonic generator according to claim 1, wherein m is a natural number. The ultrasonic wave generator according to claim 2, wherein the conditions represented by the expressions (1) and (2) are satisfied within a range of ± 5% of the size of the distance h. An ultrasonic wave generation array comprising a plurality of ultrasonic wave generation devices according to any one of claims 1 to 3, wherein the plurality of ultrasonic wave generation devices are arranged in an array. 5. The ultrasound generating array according to claim 4, wherein a horn of some or all of the plurality of ultrasound generating devices is integrally formed. Each of the plurality of ultrasonic generators has a central axis for emitting ultrasonic waves,
The ultrasound generating array according to claim 4 or 5, wherein central axes of some or all of the plurality of ultrasound generating devices have an intersection point intersecting each other. And a drive circuit for driving the plurality of ultrasonic wave generators.
The set of ultrasonic generators such that the difference in distance from each ultrasonic generator to the intersection is an integral multiple of the wavelength between the sets of ultrasonic generators at which the central axes intersect at the intersection. Is placed,
The ultrasonic generation array according to claim 6, wherein the drive circuit drives the set of ultrasonic generators simultaneously. The ultrasonic generation array according to any one of claims 4 to 7,
An ultrasonic tactile sense presentation device comprising: a controller for controlling the ultrasonic generation array so as to present a tactile sensation to a user by the ultrasonic waves generated from the ultrasonic generation array. An ultrasonic element for generating an ultrasonic wave having a predetermined frequency;
A horn disposed so as to surround the sound emitting surface from which the ultrasonic element emits the ultrasonic wave;
The horn has an opening end forming an opening surface facing the sound emitting surface of the ultrasonic element, and an inner wall surrounding a space from the opening surface to the sound emitting surface.
The difference between the straight distance, which is the distance between the sound emitting surface and the opening surface, and the reflection distance, which is the distance from the sound emitting surface to the opening end via the reflection position on the inner wall, An ultrasonic generator in which the horn is arranged so as to be an integral multiple of a wavelength corresponding to an ultrasonic frequency.