JP2023161626A - Vibration generator system and electronic apparatus - Google Patents

Abstract

To provide a vibration generator system and an electronic apparatus which can present excellent touch feeling while suppressing finger contact sound and finger friction sound.SOLUTION: A vibration generator system comprises: a vibrator; and a piezoelectric actuator. The vibrator includes: a base material; and a particle-containing layer formed on a surface of the base material. The vibrator includes a first principal surface, which is a front face of the particle-containing layer, and a second principal surface, which is the opposite side of the first principal surface. The particle-containing layer includes: a plurality of particles made of inorganic material where the median diameter of the particles is 8 μm or more and 30 μm or less; and resin material which coats the surface of the base material and fixes the plurality of particles on the surface of the base material. The plurality of particles are exposed on the first principal surface where the area ratio of the plurality of particles is 2% or more and 45% or less when viewed from a direction perpendicular to the first principal surface, and the piezoelectric actuator is bonded with the second principal surface.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a vibration generator and electronic equipment related to tactile sensation presentation using vibration.

Touch panels such as smartphones and car navigation systems use a technology (force feedback) that notifies users of input via vibration. In addition to notifications, in recent years haptic technology has been studied that uses various variations in the vibration of the panel to express the feel of displayed objects and to recognize the operating position.

As a haptic technology, it is possible to generate standing waves on the panel surface by attaching piezoelectric actuators to the panel and generating vibrations in the ultrasonic band. When the user touches the surface with a finger or the like, the user can feel the tactile sensation. By changing the signal pattern, it is possible to express a variety of tactile sensations.

However, when a finger touches the panel surface that generates such a tactile sensation, an abnormal sound (hereinafter referred to as contact sound) may be generated due to the contact between the finger and the panel. On the other hand, Patent Document 1 discloses a technique for reducing the finger contact sound by increasing the surface roughness of the panel surface. Further, Patent Document 2 proposes a method of suppressing finger contact noise by providing unevenness with a width of 1 mm to 10 mm and a depth of 0.01 mm to 0.1 mm on the panel surface.

JP2019-16111A JP 2021-137735 Publication

As mentioned above, Patent Documents 1 and 2 disclose techniques for suppressing finger contact noise by changing the properties of the panel surface. On the other hand, depending on the properties of the panel surface, when a finger touches a panel surface that does not generate a tactile sensation, an abnormal sound (hereinafter referred to as finger friction sound) may be generated due to the friction between the finger and the panel surface. Further, depending on the properties of the panel surface, the panel surface may have an undesirable rough texture.

In view of the above circumstances, an object of the present invention is to provide a vibration generator and an electronic device that can provide a good tactile sensation while suppressing finger contact sounds and finger friction sounds.

In order to achieve the above object, a vibration generator according to one embodiment of the present invention includes a vibrating body and a piezoelectric actuator.
The vibrating body includes a base material and a particle-containing layer formed on a surface of the base material, and a first main surface that is a surface of the particle-containing layer, and a side opposite to the first main surface. The particle-containing layer is made of an inorganic material and coats the surface of the base material with a plurality of particles having a median diameter of 8 μm or more and 30 μm or less. a resin material for fixing the particles to the surface of the base material, the plurality of particles are exposed on the first main surface, and the plurality of particles are exposed in the direction perpendicular to the first main surface. The area ratio is 2% or more and 45% or less.
The piezoelectric actuator is joined to the second main surface.

The vibrating body may include a panel and a film attached to the surface of the panel, the base material and the particle-containing layer may constitute the film, and the first main surface may be a surface of the film. .

The above film may have a thickness of 30 μm or more and 200 μm or less.

The vibrating body may include the panel as the base material and the particle-containing layer formed on the surface of the panel.

The panel may be made of resin or glass.

The vibrating body may have optical transparency.

In order to achieve the above object, an electronic device according to one embodiment of the present invention includes a vibration generator.
The vibration generator includes a base material and a particle-containing layer formed on a surface of the base material, and has a first main surface that is a surface of the particle-containing layer, and a first main surface opposite to the first main surface. The vibrating body has a second main surface on the side, and the particle-containing layer is made of an inorganic material and coats the surface of the base material with a plurality of particles having a median diameter of 8 μm or more and 30 μm or less, a resin material for fixing a plurality of particles to the surface of the base material, the plurality of particles are exposed on the first main surface, and the plurality of particles are viewed from a direction perpendicular to the first main surface. The vibrating body has an area ratio of 2% or more and 45% or less, and a piezoelectric actuator joined to the second main surface.

As described above, according to the present invention, it is possible to provide a vibration generator and an electronic device that can provide a good tactile sensation while suppressing finger contact sounds and finger friction sounds.

1 is a schematic diagram of a vibration generator according to an embodiment of the present invention. It is a perspective view of the above-mentioned vibration generator. FIG. 3 is a side view of the vibration generator. It is a sectional view of the vibrating body with which the above-mentioned vibration generator is provided. FIG. 3 is an exploded cross-sectional view showing a vibrating body included in the vibration generator. FIG. 3 is a plan view of a particle-containing layer included in the vibrating body. 7 is a graph showing sound pressure characteristics of a vibrating body according to a comparative example. It is a graph showing sound pressure characteristics of a vibrator included in the vibration generator according to the embodiment of the present invention. It is a graph which shows the relationship between the area ratio of particles and sound pressure of the particle containing layer with which the said vibration generator is provided. It is a graph showing the relationship between the particle size of particles and finger contact sound in the above-mentioned particle-containing layer. It is a graph showing the relationship between particle size and finger friction sound in the particle-containing layer. It is a graph showing the relationship between the particle size and the tactile sensation of the particles in the particle-containing layer. It is a graph which shows the relationship between the thickness of the film with which the said vibration generator is equipped, and displacement amount. FIG. 7 is a cross-sectional view of a vibrating body having another configuration according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a vibrating body having another configuration according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a vibrating body having another configuration according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a vibrating body having another configuration according to an embodiment of the present invention.

A vibration generator according to an embodiment of the present invention will be described. Note that in each of the following figures, the X direction, Y direction, and Z direction are three directions that are orthogonal to each other.

[Configuration of vibration generator]
FIG. 1 is a schematic diagram of a vibration generator 100 according to this embodiment. As shown in the figure, the vibration generator 100 includes a vibrating body 101, a piezoelectric actuator 102, and a drive device 103. FIG. 2 is a perspective view of the vibration generator 100, and FIG. 3 is a side view of the vibration generator 100. Note that illustration of the drive device 103 is omitted in FIGS. 2 and 3.

The vibrating body 101 presents a tactile sensation to a user who touches the vibrating body 101. The vibrating body 101 is a panel-shaped member, such as a liquid crystal panel or a housing of an electronic device. The shape and size of the vibrating body 101 are not particularly limited. As shown in FIGS. 2 and 3, one main surface of the vibrating body 101 is a first main surface 101a, and the main surface opposite to the first main surface 101a is a second main surface. The detailed configuration of the vibrating body 101 will be described later.

The piezoelectric actuator 102 is joined to the second main surface 101b of the vibrating body 101 and generates vibration. The piezoelectric actuator 102 includes a positive electrode, a negative electrode, and a piezoelectric material layer, and when a voltage is applied between the positive electrode and the negative electrode, the piezoelectric material layer is deformed due to an inverse piezoelectric effect, and vibration is generated. In FIG. 1, a positive terminal 102a connected to the positive electrode and a negative terminal 102b connected to the negative electrode are shown.

A positive electrode wiring 104 is connected to the positive electrode terminal 102a, and a negative electrode wiring 105 is connected to the negative electrode terminal 102b. As shown in FIG. 1, the positive electrode wiring 104 and the negative electrode wiring 105 are connected to a driving device 103, and when a driving signal is supplied from the driving device 103, vibration occurs in the piezoelectric actuator 102.

The piezoelectric actuator 102 may have a laminated structure in which positive electrodes and negative electrodes are alternately laminated with piezoelectric material layers interposed therebetween, or may have another structure. The piezoelectric actuator 102 may be bonded to the second main surface 101b using epoxy resin or the like. Further, as shown in FIGS. 15 to 17, two or more piezoelectric actuators 102 may be joined to the second main surface 101b in a pair or parallel arrangement.

As shown in FIG. 3, the vibration generator 100 is used with the user's finger F in contact with the first main surface 101a. At this time, the piezoelectric actuator 102 bonded to the second main surface 101b generates ultrasonic vibrations, thereby generating standing waves in the vibrating body 101, allowing the user to sense a tactile sensation on the finger F. Further, by changing the signal pattern of the drive signal applied to the piezoelectric actuator 102, various variations of tactile sensations can be generated in the vibrating body 101.

The drive device 103 is, for example, an amplifier, is connected to the piezoelectric actuator 102 via a positive electrode wiring 104 and a negative electrode wiring 105, and supplies a driving signal to the piezoelectric actuator 102. The frequency of the drive signal is not particularly limited, but is preferably 60 kHz or higher.

[About the vibrating body]
The detailed configuration of the vibrating body 101 will be explained. FIG. 4 is a cross-sectional view of the vibrating body 101, and FIG. 5 is a cross-sectional view showing the vibrating body 101 in an exploded manner. As shown in these figures, the vibrating body 101 includes a panel 111, a film 112, and an adhesive layer 113.

The panel 111 is a plate-like member made of glass or resin material. When the panel 111 is made of a resin material, a resin material having a bending elastic modulus of 3.0 GPa or more is suitable. As shown in FIG. 5, the panel 111 has a front surface 111a and a back surface 111b. The back surface 111b constitutes the second main surface 101b of the vibrating body 101, and is a surface to which the piezoelectric actuator 102 is bonded.
The thickness of the panel 111 can be approximately 0.3 mm to several mm.

Film 112 is attached to surface 111a of panel 111 by adhesive layer 113. Film 112 includes a base material 114 and a particle-containing layer 115, as shown in FIG. The thickness of the film 112 is preferably 30 μm or more and 200 μm or less.

The base material 114 is a film-like member made of a resin material such as PET (Polyethylene Terephthalate). As shown in FIG. 5, the base material 114 has a front surface 114a and a back surface 114b. The back surface 114b is the surface on the adhesive layer 113 side, and the front surface 114a is the surface on the opposite side.

Particle-containing layer 115 includes a plurality of particles 116 and resin material 117. The particles 116 are particles made of an inorganic material, specifically silica, glass beads, glass flakes, calcium carbonate, talc, magnesium oxide, or the like. The particles 116 have a median diameter of 8 μm or more and 30 μm or less, and the particle size range is ±20% of the median diameter. The median diameter is also called "D50" and means a particle size at which when particles are divided by a specific particle size, the amount of particles larger and smaller than the same particle size is equal. The resin material 117 covers the surface 114a of the base material 114 and fixes the particles 116 to the surface 114a. The resin material 117 is a resin material such as silicon resin or acrylic resin.

As shown in FIG. 5, particle-containing layer 115 has a surface 115a. Surface 115a is the opposite surface opposite to base material 114. The particle-containing layer 115 is located on the outermost surface of the vibrating body and constitutes the first main surface 101a.

As shown in FIG. 4, in the particle-containing layer 115, the particles 116 protrude from the resin material 117 and are exposed on the first main surface 101a. FIG. 6 is a plan view of the particle-containing layer 115 viewed from a direction (Z direction) perpendicular to the first main surface 101a. As shown in the figure, when viewed from the same direction, the first main surface 101a has particles 116 dispersed in the resin material 117 and exposed. When a square range of 227 μm on a side is defined as a measurement range on the surface 115a of the particle-containing layer 115, the area ratio of the particles 116 occupying the surface 115a in the measurement range is 2% or more and 45% or less.

Although the method of forming the particle-containing layer 115 is not particularly limited, it can be formed by applying a fluid resin material 117 to the surface 114a of the base material 114, scattering particles 116 thereon, and curing the resin material 117. A particle-containing layer 115 can be formed.

Adhesive layer 113 is placed between panel 111 and film 112 to bond them together. The adhesive layer 113 may be made of any material as long as it can bond the panel 111 and the film 112 together. The thickness of the adhesive layer 113 is preferably 10 μm or more and 50 μm or less.

The vibrating body 101 has the above configuration. When the vibrating body 101 is attached to a display device such as a liquid crystal panel or constitutes a part of the display device, it is preferable that the vibrating body 101 has light transmittance.

[About particle-containing layer]
In the vibration generator 100, by forming the particle-containing layer 115 on the first main surface 101a that is touched by the user's finger F, both finger contact sound and finger friction sound can be reduced. The finger contact sound is a sound generated when the piezoelectric actuator 102 generates ultrasonic vibration and the finger F is moved on the first main surface 101a while a standing wave is generated in the vibrating body 101. The finger friction sound is a sound generated when the finger F is moved on the first main surface 101a while the piezoelectric actuator 102 is not being driven.

For comparison, FIG. 7 is a graph showing the sound pressure characteristics when a vibrating body with a flat surface without the film 112 attached is vibrated in an ultrasonic band. In the figure, "no finger" indicates the sound pressure characteristics when no finger is touching the vibrating body, and "finger contact" indicates the sound pressure characteristic when the finger is touching the vibrating body. As shown in the figure, when a finger touches the vibrating body, there is a peak at the input frequency to the piezoelectric actuator and a frequency that is 1/4 of that frequency, and the peak at the 1/4 frequency is in the audible range, so the finger contact noise is generated. It sounds like.

On the other hand, FIG. 8 is a graph showing sound pressure characteristics when the vibrating body 101 including the film 112 according to the present embodiment is vibrated in an ultrasonic band. In the figure, "no finger" indicates the sound pressure characteristics when no finger is touching the vibrating body, and "finger contact" indicates the sound pressure characteristic when the finger is touching the vibrating body. As shown in the figure, when a finger touches the vibrating body, almost no peak occurs at a frequency that is 1/4 of the input frequency to the piezoelectric actuator, and the finger contact sound is suppressed.

FIG. 9 shows the relationship between the area ratio of the particles 116 occupying the measurement range of the surface 115a and the sound pressure when the particle-containing layer 115 is viewed from the direction (Z direction) perpendicular to the first main surface 101a (see FIG. 6). This is a graph showing. As shown in the figure, when the area ratio is 0% (no particles), the finger contact sound is loud, when it is 2% or more, the finger contact sound is small, and when it is 45% or more, it becomes the same level as 0%. Therefore, the above area ratio is preferably 2% or more and 45% or less.

FIG. 10 is a graph showing the relationship between the particle size (D50) of the particles 116 and the finger contact sound, and FIG. 11 is a graph showing the relationship between the particle size (D50) of the particles 116 and the finger friction sound. As shown in FIG. 10, the larger the particle size (D50) of the particles 116 is, the more the finger contact sound is reduced, and when the particle size is 8 μm or more, the finger contact sound becomes less than the threshold value, and when the particle size is 15 μm or more, no finger contact sound is generated. On the other hand, as shown in FIG. 11, the larger the particle size (D50) of the particles 116 is, the more the finger friction sound increases, and the finger friction sound exceeds the threshold value from 30 μm or more.

FIG. 12 is a graph showing the relationship between the particle size (D50) of the particles 116 and the tactile sensation of the first principal surface 101a. On the vertical axis of the graph, a state in which the first principal surface 101a is smooth is defined as "good", and a state in which the first principal surface 101a is rough is defined as "bad". As shown in the figure, when the particle size (D50) of the particles 116 is 30 μm or more, the tactile sensation of the first main surface 101a is reduced.

From the above, by setting the area ratio of the particles 116 in the measurement range of the surface 115a to 2% or more and 45% or less, and the particle diameter (D50) of the particles 116 to 8 μm or more and 30 μm or less, finger contact sounds and finger friction sounds are suppressed. However, the first principal surface 101a can have a good tactile feel.

[About film thickness]
The thickness of the film 112 will be explained. FIG. 13 is a graph showing the relationship between the thickness of the film 112 and the amount of displacement of the first principal surface 101a. As shown in the figure, the thinner the film 112 is, the larger the amount of displacement of the first main surface 101a is. However, if the thickness of the film 112 is 30 μm or less, it is difficult to make the first main surface 101a a desired rough surface, and the film 112 becomes thinner. If the thickness of the first main surface 101a is 200 μm or more, the amount of displacement of the first main surface 101a due to ultrasonic vibration becomes small. Therefore, the thickness of the film 112 is preferably 30 μm or more and 200 μm or less.

[About other configurations of the vibrating body]
As described above, the vibrating body 101 has been described as having the film 112 including the particle-containing layer 115 adhered to the panel 111, but the particle-containing layer 115 may be laminated directly on the panel 111. good. FIG. 14 is a cross-sectional view of the vibrating body 101 having this configuration. As shown in the figure, the vibrating body 101 includes a panel 111 and a particle-containing layer 115 laminated on the panel 111.

The panel 111 is a plate-like member made of glass or resin material as described above, and has a front surface 111a and a back surface 111b. The back surface 111b constitutes the second main surface 101b of the vibrating body 101, and is a surface to which the piezoelectric actuator 102 is bonded. In this configuration, panel 111 is the substrate for particle-containing layer 115.

Particle-containing layer 115 has the above-described configuration and includes a plurality of particles 116 and resin material 117. The resin material 117 covers the surface 111a of the panel 111, which is a base material, and fixes the particles 116 to the surface 111a. The particle size and area ratio of the particles 116 are the same as those of the particle-containing layer 115 in the film 112. Also in this configuration, by setting the area ratio of the particles 116 in the measurement range of the surface 115a to 2% or more and 45% or less and the particle diameter (D50) of the particles 116 to 8 μm or more and 30 μm or less, finger contact sounds and finger friction sounds can be generated. can be suppressed, and the tactile sensation of the first main surface 101a can be made good.

The vibration generator 100 has the above configuration. The vibration generator 100 can be installed in various electronic devices such as smartphones and tactile function devices.

DESCRIPTION OF SYMBOLS 100... Vibration generator 101... Vibrating body 102... Piezoelectric actuator 103... Drive device 111... Panel 112... Film 113... Adhesive layer 114... Base material 115... Particle-containing layer 116... Particle 117... Resin material

Claims (7)

a base material, a particle-containing layer formed on the surface of the base material, a first main surface that is the surface of the particle-containing layer, and a second main surface opposite to the first main surface. The particle-containing layer is made of an inorganic material and coats the surface of the base material with a plurality of particles having a median diameter of 8 μm or more and 30 μm or less, and the particle-containing layer is made of an inorganic material and covers the surface of the base material, and the particle-containing layer is made of an inorganic material and coats the surface of the base material. a resin material fixed to the surface of the material, the plurality of particles are exposed on the first main surface, and the area ratio of the plurality of particles is 2% when viewed from a direction perpendicular to the first main surface. a vibrating body with a vibration rate of at least 45%;
and a piezoelectric actuator joined to the second main surface. The vibration generator according to claim 1,
The vibrating body includes a panel and a film attached to the surface of the panel, the base material and the particle-containing layer constitute the film, and the first main surface is the surface of the film. Vibration generator . The vibration generator according to claim 2,
The film has a thickness of 30 μm or more and 200 μm or less. Vibration generator. The vibration generator according to claim 1,
The vibrating body includes a panel as the base material and the particle-containing layer formed on the surface of the panel. The vibration generator. The vibration generator according to claim 2 or 4,
The panel is made of resin or glass. The vibration generator. The vibration generator according to any one of claims 1 to 4,
The vibration generating device wherein the vibrating body has optical transparency. a base material, a particle-containing layer formed on the surface of the base material, a first main surface that is the surface of the particle-containing layer, and a second main surface opposite to the first main surface. The particle-containing layer is made of an inorganic material and coats the surface of the base material with a plurality of particles having a median diameter of 8 μm or more and 30 μm or less, and the particle-containing layer is made of an inorganic material and covers the surface of the base material, and the particle-containing layer is made of an inorganic material and coats the surface of the base material. a resin material fixed to the surface of the material, the plurality of particles are exposed on the first main surface, and the area ratio of the plurality of particles is 2% when viewed from a direction perpendicular to the first main surface. An electronic device comprising: a vibration generating device comprising a vibrating body having a vibration rate of 45% or less, and a piezoelectric actuator joined to the second main surface.

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