JP7672124B2 - Vibration presentation element and its manufacturing method - Google Patents

Description

The present invention relates to a vibration presentation element and a method for manufacturing a vibration presentation element.

In recent years, haptic devices that stimulate people's sense of touch, such as tablet terminals, game controllers, and feedback mechanisms for remote control of equipment, have become known (for example, Patent Document 1, etc.).

Patent document 1 discloses a configuration in which a vibration motor is placed as an actuator at the edge of a touch panel, and the entire touch panel is vibrated with a substantially uniform vibration magnitude.

Patent document 2 also describes a haptic device in which a PVC gel actuator is provided with multiple convex structures, and the actuator displaces the convex structures to increase the spacing between the convex structures, thereby applying tensile strain to the skin and stimulating the sense of touch.

JP 2012-137971 A JP 2019-133274 A

By mounting such haptic devices on clothing or the like to make them wearable, it is expected that the applications of this technology will be further expanded. However, when using actuators such as those described in Patent Documents 1 and 2, it is difficult to make the haptic device smaller (thinner) and lighter, which poses a problem in making it wearable.

In response to this, by using a piezoelectric actuator that generates displacement through the piezoelectric effect, it is possible to make haptic devices smaller (thinner) and lighter. However, to obtain an effective haptic effect from that displacement, a high voltage (e.g., several tens of volts) must be applied, which is problematic as it is not suitable for wearable devices.

In view of the above problems, the present invention aims to provide a technology that can obtain a vibration presentation element that efficiently presents vibrations to the skin of a living body while being compact, thin, and low-voltage.

In order to solve the above problems, the vibration presentation element according to the present invention comprises:
A vibration presentation element that presents vibration to the skin of a living body,
A piezoelectric actuator that generates vibrations by a piezoelectric effect; and a hair structure including a plurality of hairs that receive vibrations from the piezoelectric actuator, resonate, and present the vibrations to the skin of the living body.
It is characterized by:

Here, the piezoelectric actuator may be an actuator using a piezoelectric material, whether inorganic (e.g., PZT, etc.) or organic (e.g., PVDF, etc.), but a thin-film type with flexibility is preferable. The capillaries may be made of any desired fiber material, such as nylon fiber, polyester fiber, or rayon fiber.

With this configuration, the sensory receptors present in the skin of the living body are stimulated by the hairs that resonate with the vibrations from the piezoelectric actuator, making it possible to effectively present vibrations to the skin of the living body even with a piezoelectric actuator that is driven at a low voltage.

The piezoelectric actuator may generate vibrations in a direction perpendicular to the surface of the skin of the living body. With this configuration, it is possible to efficiently stimulate sensory receptors located deep below the surface of the skin of the living body.

The hair-like structure may also include hairs whose tips vibrate horizontally relative to the skin surface of the living body. With this configuration, it is possible to efficiently stimulate sensory receptors located close to the skin surface of the living body.

The hair structure may include multiple types of hairs with different shapes. The multiple types of hairs may vibrate at different natural frequencies. With this configuration, it is possible to provide a single hair structure with hairs that provide optimized vibrations for each of the multiple types of sensory receptors present on the skin surface of a living body. The natural frequency may be adjusted to a desired value by adjusting the length, thickness (diameter), and other shapes of the hairs.

The living body may be a human body, and the hair-like structure may include at least a first hair-like body that vibrates at a frequency that maximizes stimulation of Meissner's corpuscles, which are sensory receptors present in the skin, when the hair-like structure comes into contact with the skin of the human body, and a second hair-like body that vibrates at a frequency that maximizes stimulation of Merkel's disks, which are sensory receptors present in the skin. The hair-like structure may further include a third hair-like body that vibrates at a frequency that maximizes stimulation of Pacinian corpuscles, which are sensory receptors present in the skin, when the hair-like structure comes into contact with the skin of the human body.

The applied voltage of the piezoelectric actuator may be set so that the piezoelectric actuator vibrates with a waveform that includes the resonant frequencies of all of the hair bodies. This makes it possible to cause hair bodies, each of which has a different natural frequency, to resonate together using a single piezoelectric actuator.

The piezoelectric actuator may further include a sealing portion that seals the piezoelectric actuator, the hair-like structure may be provided on the surface of the sealing portion, and vibrations from the piezoelectric actuator may be transmitted to the hair-like structure via the sealing portion.

Here, the sealing portion may be formed by filling with a flexible sealing material, by bonding a film with an adhesive, or by thermocompression bonding of the film with a laminator. The hair-like structure may be formed by nanoimprinting using a mold, by making a plate of the hair-like structure out of polydimethylsiloxane (PDMS) and transferring it, by bonding a plate formed by a 3D printer, or by forming a brushed structure by electrostatic flocking.

In addition, a method for producing a vibration presentation element according to the present invention includes the steps of:
A first step of applying an adhesive to a first laminate film as a sealing material;
a second step of placing a piezoelectric actuator on the adhesive applied in the first step;
a third step of connecting wiring to the piezoelectric actuator arranged in the second step;
a fourth step of covering an area including the piezoelectric actuator and the wiring with a second laminate film as a sealing material;
a fifth step of laminating the first laminate film and the second laminate film to form a sealing portion that seals the piezoelectric actuator and the wiring;
and a sixth step of exposing, as a terminal, a portion of the wiring sealed in the fifth step.

The method for producing the vibration presentation element further comprises the steps of:
a seventh step of applying an adhesive to a surface of the sealing portion in an area where the piezoelectric actuator is sealed;
The method may further include an eighth step of electrostatically implanting hair-like bodies in the adhesive applied in the seventh step to form a hair-like structure.

The present invention provides a technology that can obtain a vibration presentation element that efficiently presents vibrations to the skin of a living body while being compact, thin, and low-voltage.

1A and 1B are schematic cross-sectional and plan views of a vibration presentation element according to an embodiment of the present invention; FIG. 2 is a diagram showing an outline of the piezoelectric actuator according to the embodiment. FIG. 3 is a diagram illustrating the sensory receptors present on the skin and the vibration characteristics of hairs relative to the skin surface. FIG. 4 is a table showing the depth and maximum sensitivity frequency of sensory receptors present in the skin. FIG. 5 is a flowchart showing a flow of a method for manufacturing a vibration presentation element according to the embodiment. 6A, 6B, 6C, 6D, 6E, 6F, 6G, and 6H are schematic diagrams illustrating steps in the manufacture of a vibration presentation element according to an embodiment. 7A and 7B are a first and second diagrams illustrating a modified example of the vibration presentation element according to the embodiment;

Below, an example of an embodiment to which the present invention is applied will be described with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the invention to those alone.

<Embodiment>
Fig. 1 is a diagram showing an outline of a vibration presentation element 1 according to the present embodiment, Fig. 1A is a schematic cross-sectional view of the vibration presentation element 1, and Fig. 1B is a schematic plan view of the vibration presentation element 1. The vibration presentation element 1 is a wearable haptic device that is mounted on clothing, accessories, or the like worn by a person and presents vibration to the skin of the wearer.

(Configuration of vibration presentation element)
1, the vibration presentation element 1 generally includes a piezoelectric actuator 10, a sealing portion 30 that seals the piezoelectric actuator 10, and a hair-like structure 20. When the vibration presentation element 1 is mounted, the piezoelectric actuator 10 is disposed so as to generate vibrations perpendicular to the surface of the wearer's skin and so as to cause the hair-like structure 20 to come into contact with the wearer's skin.

The piezoelectric actuator 10 can be, for example, an extremely thin (e.g., 5 μm thick) MEMS (Micro Electro Mechanical Systems) device formed by a semiconductor process. Figure 2 shows a schematic configuration of the extremely thin piezoelectric actuator 10.

2, the piezoelectric actuator 10 includes a base 91 made of silicon (Si), electrode layers 92 and 94 made of, for example, platinum (Pt) electrodes, a piezoelectric layer 93 made of, for example, lead zirconate titanate (PZT), and an insulating layer 95 made of, for example, silicon dioxide (SiO ₂ ). Since the piezoelectric actuator 10 is a MEMS device formed by a semiconductor process, a semiconductor circuit (not shown) is fabricated on the base 91, and this semiconductor circuit may include circuit elements such as active elements such as integrated circuits, capacitors, inductors, and wiring, as necessary.

In addition, wiring 11 (e.g., copper wire) is connected to the piezoelectric actuator 10, and when a voltage is applied from an external power source to the piezoelectric actuator 10 via the wiring 11, vibrations are generated due to the piezoelectric effect, and the vibrations are transmitted to the wearer's skin via each hair that makes up the hair structure 20.

The sealing portion 30 can be formed, for example, by thermocompression bonding a film such as polyimide (PI) that covers the piezoelectric actuator 10. Note that the material of the film is not limited to PI, and other materials such as polyethylene terephthalate (PET) can also be used.

The hair-like structure 20 is formed by implanting three types of hairs, the first hairs 21, the second hairs 22, and the third hairs 23, each having a different shape, in the adhesive layer 40 provided on the surface of the sealing portion 30, for example, by electrostatic implantation technology. The material of each hair can be any desired fiber material, such as nylon fiber, polyester fiber, or rayon fiber.

The first hair-like body 21 and the second hair-like body are formed so that their tips vibrate horizontally relative to the wearer's skin surface, and the third hair-like body is formed so that it vibrates vertically relative to the skin surface. Figure 3 shows a model diagram of human skin H and the sensory receptors present on the skin, as well as an explanatory diagram showing the vibration characteristics of each hair-like body relative to the skin surface.

As shown in Figure 3, the sensory receptors present in the skin of the human body include Meissner's corpuscles H1 and Merkel's disks H2 that are present near the surface, and Pacinian corpuscles H3 and Ruffini endings (not shown) that are present deep below the surface. For Meissner's corpuscles H1 and Merkel's disks H2 that are present near the surface of the skin, horizontal vibration of the hairs stimulates the sensory receptors as if scratching them, effectively stimulating the sense of touch. On the other hand, horizontal vibrations are difficult to transmit to Pacinian corpuscles H3 (and Ruffini endings) that are present deep in the skin, so applying vertical vibrations is more effective.

Furthermore, the sensory receptors Meissner's corpuscles H1, Merkel's disks H2, and Pacinian corpuscles H3 each have a different vibration frequency for which they are most sensitive. Figure 4 shows a table showing the depth at which sensory receptors exist and the frequency at which they are most sensitive.

For this reason, each of the first hair 21, the second hair 22, and the third hair 23 is formed to have a different natural frequency (natural vibration frequency) according to the maximum sensitivity frequency of the sensory receptor. For example, the length, diameter, and other shapes of the hair may be adjusted to obtain a desired frequency.

Specifically, the first hair 21 has a natural frequency (e.g., 40 Hz) set so that it vibrates at a frequency that maximizes the stimulation of the Meissner's corpuscles H1. Similarly, the second hair 22 has a natural frequency (e.g., 70 Hz) set so that it maximizes the stimulation of the Merkel's disks H2, and the third hair 23 has a natural frequency (e.g., 200 Hz) set so that it maximizes the stimulation of the Pacinian corpuscles H3.

Each hair resonates at its own unique frequency upon receiving vibrations from the piezoelectric actuator 10, thereby efficiently stimulating each sensory receptor. That is, the applied voltage is set so that the piezoelectric actuator 10 vibrates with a waveform that includes the resonance frequency of each of the first hair 21, the second hair 22, and the third hair 23 (e.g., a composite wave of the unique frequencies of each hair).

(Method of manufacturing vibration presentation element)
Next, a method for manufacturing the vibration presentation element 1 according to the present embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a flow chart showing a flow of manufacturing the vibration presentation element 1 according to the present embodiment, and Fig. 6 is a schematic diagram showing each step of manufacturing the vibration presentation element 1.

As shown in Figures 5 and 6, to manufacture the vibration presentation element 1, first, an adhesive for adhering the piezoelectric actuator is applied onto the laminate film 31 that will become part of the sealing portion 30 (S101, Figure 6A). Next, the piezoelectric actuator 10 is placed on the adhesive and adhered (S102, Figure 6B). Next, wiring 11 that is connected to the piezoelectric actuator 10 is provided (S103, Figure 6C).

Next, the piezoelectric actuator 10 and the wiring 11 are covered with the laminate film 32 (S104, FIG. 6D), and the laminate films 31 and 32 are thermocompression bonded by a laminate heater (not shown) (S105, FIG. 6E), forming the sealing portion 30. Next, the sealing portion at the end of the wiring 11 is cut out to expose the wiring 11, and a terminal is formed (S106, FIG. 6F).

Next, adhesive is applied to the surface of the sealing portion in the area where the piezoelectric actuator 10 is sealed (S107, FIG. 6G), and the fibers that will become the hairs are planted in the adhesive using an electrostatic planting technique to form the hair-like structure 20 (S108, FIG. 6H), and the manufacturing process is completed.

As described above, the vibration presentation element 1 according to this embodiment is a vibration presentation element using a small piezoelectric actuator that is driven at a low voltage, but it is capable of effectively presenting vibrations by providing optimized stimuli to each of the sensory receptors with different characteristics.

<Modification>
In addition, the vibration presentation element 1 according to the above embodiment merely exemplifies the present invention, and the present invention is not limited to the above specific form. The present invention can be modified in various ways within the scope of its technical concept. For example, the hair structure 20 of the vibration presentation element 1 according to the above embodiment has three types of hairs on only one surface of the sealing portion 30, but the present invention is not limited to such a configuration. Figure 7 shows several modified examples of the vibration presentation element 1.

For example, as shown in Fig. 7A, two types of hairs may be used, or the hair structure may be composed of only one type of hairs. Also, as shown in Fig. 7B, the hair structures may be provided on multiple surfaces of the sealing portion. Also, the length, diameter, and other shapes of the hairs may be freely changed.

In this way, the hair structure can be formed with the desired hair bodies, and the length and diameter of the hair bodies can be adjusted to match the irregularities of the human body structure (for example, making the diameter thicker since making the hairs longer lowers the natural frequency), making it possible to transmit vibrations appropriately even in concave areas.

In addition, in the above embodiment, the hair-like structures are formed by electrostatic hair transplantation, but they may be formed by nanoimprinting using a mold, or by creating a plate of the hair-like structures out of PDMS and transferring this, or by attaching structures formed by a 3D printer.

In addition, in the above embodiment, the piezoelectric actuator was a MEMS device equipped with an organic piezoelectric material made of PZT, but this is not limited thereto, and any desired piezoelectric actuator can be adopted.

In addition, in the above embodiment, the sealing portion is formed by thermocompression bonding the laminate film, but the sealing portion may also be formed by filling with a sealing material, bonding the film with an adhesive, etc.

REFERENCE SIGNS LIST 1: vibration presentation element 10: piezoelectric actuator 11: wiring 20: hair-like structure 21: first hair 22: second hair 23: third hair 30: sealing portion 31, 32: laminate film 40: adhesive layer H: skin H1: Meissner's corpuscles H2: Merkel's disk H3: Pacinian corpuscles

Claims (6)

A vibration presentation element that presents vibration to the skin of a human body ,
A piezoelectric actuator that generates vibrations by a piezoelectric effect; and a hair structure including a plurality of hairs that receive vibrations from the piezoelectric actuator, resonate with the vibrations, and present the vibrations to the skin of the human body ,
The hair structure includes a plurality of types of hairs having different shapes that vibrate at different natural frequencies, and includes at least a first hair that vibrates at a frequency that maximizes stimulation of Meissner's corpuscles, which are sensory receptors present on the skin, when in contact with the skin, and a second hair that vibrates at a frequency that maximizes stimulation of Merkel's disks, which are sensory receptors present on the skin.
A vibration presentation element comprising: The piezoelectric actuator generates vibrations in a direction perpendicular to the surface of the skin of the human body .
The vibration presentation element according to claim 1 . The hair-like structure includes a hair-like body whose tip vibrates horizontally relative to the skin surface of the human body .
The vibration presentation element according to claim 1 or 2, characterized in that: The hair-like structure further includes a third hair-like body that vibrates at a frequency that maximizes stimulation of Pacinian corpuscles, which are sensory receptors present in the skin, when the hair-like structure contacts the skin of a human body.
The vibration presentation element according to claim 1 . An applied voltage is set so that the piezoelectric actuator vibrates with a waveform including the resonant frequencies of all of the capillaries.
The vibration presentation element according to claim 1 , The piezoelectric actuator further includes a sealing portion that seals the piezoelectric actuator.
The hair-like structure is provided on the surface of the sealing portion,
Vibrations from the piezoelectric actuator are transmitted to the capillary structure via the sealing portion.
The vibration presentation element according to claim 1 ,

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