JPH08294260A - Vibration actuator for portable equipment - Google Patents

Abstract

PURPOSE: To accurately transmit generated vibration to a carrier by arranging a core member, which has a projection at the top and a spring member at the bottom, freely of coming in and out into an air coil fixed to the top cover. CONSTITUTION: When power 52 is turned on by a power switch 55, a current flows to an air core coil 16 for driving, and a magnetic field is generated in the direction of A. This magnetic field draws a core member 18, a permanent magnet 20, and a yoke 21 in direction A. At this time, an air core coil 16' for position detection detects the shifting into the air core coils 16 and 16' of a core member 18, and inputs this detected voltage into one terminal of a comparator 54. For the voltage inputted into the other of the comparator 54, the voltage applied to the air core coil 16 is fed back by a feedback resistor Rf. The output voltage of the comparator 54 at this time turns off the transistor 53 provided between the air core coil and a power source 52. As a result, a core member 18, etc., return to the their places by the restorative force of a plate spring 17 working in the direction B. This operation is repeated, and reciprocation is performed, and it is transmitted to a carrier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention transmits a vibration generated by a vibration actuator to a wearer in an information transmission device such as a portable device such as a card type pager, a wristwatch, a mobile phone, or a signal receiver for the blind. The present invention relates to a vibration actuator for a mobile device that transmits a certain kind of information to a wearer of the mobile device. Hereinafter, in the present specification, a device that transmits certain information by transmitting vibration to the human body is simply referred to as an “information transmission device”.

[0002]

2. Description of the Related Art An information transmission device using a vibration motor is
Since it is possible to transmit a certain kind of information to surrounding people only by vibration, it has come to be used in pagers, wrist watches, cell phones, or signal receivers for the blind, which are replaced by pagers in recent years. . In the vibration motor in the conventional example, for example, a crescent-shaped weight is attached to the tip of the motor shaft of a cylindrical motor, and the motor is rotated at high speed to obtain vibration. Since it is difficult to make such a cylindrical motor thin as a card type portable information transmission device, a flat vibration actuator has been developed.

FIG. 6 is a diagram for explaining a flat type vibration actuator in a conventional example. In FIG. 6, the air-core coil including the drive coil 61 and the position detection coil 62 is, for example, concentric and wound in the same plane. The air-core coil is fixed between the permanent magnet 63 and the opposing yoke 64 via an air gap. Further, at least one of the permanent magnet 63 and the facing yoke 64 constitutes a mover 65, and one end of the spring member 66 is fixed to the spring member support base 67 as a cantilever beam.
Supported by.

When a current flows through the drive coil 61 that drives the mover 65, an electromagnetic force is generated in the coil by the current and the magnetic field of the permanent magnet 63, and the mover 65 moves in the same plane as the coil. To do. When the mover 65 moves, the position detection coil 62 reduces the electromotive force and inputs this voltage to a comparator (not shown). The voltage applied to the drive coil 61 is fed back to the other input of the comparator. The output of the comparator at this time works so that the switch between the drive coil 61 and the power supply is turned off. When no current flows through the drive coil 61, the mover 65 returns to its original position due to the restoring force of the spring member 66, and becomes the initial state.

Then, the O of the current flowing through the drive coil 61
By the N / OFF and the spring member 66, the mover 65 is
Repeats a continuous reciprocating motion in the same plane as the coil. The cycle of this reciprocating motion is the same as the permanent magnet 6
3, determined by the mass of the opposing yoke 64 and the spring constant of the spring member 66. The spring constant is the shape of the spring member 66,
For example, it can be formed into a substantially U shape when viewed from the front, or can be changed depending on the material. The mover 65 receives a force that moves in a plane parallel to the coil surface while the current flows through the drive coil 61 as described above. When the current stops flowing, the mover 65 returns to its original position by the force of the spring member 66. Return to. Therefore, the current consumption is small and the control circuit is simple. The structure of the vibration actuator is substantially the same as the thickness of the coil wound on the same plane, the permanent magnet 63, the back yoke 68, and the opposing yoke 64. In addition, in order to make the movable element 65 reciprocate efficiently, the supporting spring member 66 is used.
Is designed to resonate by appropriately selecting the mass of the mover 65 and the spring member 66 and the material of the spring member 66.

[0006]

In a vibration source using a cylindrical motor or a flat motor, the vibration motor is rotated at a high speed by a weight having an unbalanced mass attached to its shaft. Since the battery capacity to be driven is large, it was not possible to make a small and thin vibration source for portable devices. Further, the vibration motor described above has a shortened service life due to wear of a rotating portion such as a shaft due to vibration, and is an expensive vibration source because expensive tungsten or the like is used for the weight. Also, in the above vibration motor,
When there is a brush or a commutator, there is a problem that the sliding noise, the impact noise to the bearing, or the mechanical noise caused by them is large. Further, since the flat type motor that solves some of the above problems is coreless, the torque generation efficiency is poor and the current consumption is large.

In order to solve the above problems, the present applicant has
The vibration type actuator shown in Fig. 6 has been developed. The vibration-type actuator has the advantages that it consumes less current than a vibration generator including a coreless motor and that the thickness thereof can be reduced. However, the vibration-type actuator shown in FIG. 6 has a drawback that when incorporated into a pager or wristwatch, it vibrates in a direction parallel to the surface of the body, resulting in weak vibration and unpleasant feeling.

In order to solve the above problems, it is an object of the present invention to provide a vibration actuator for portable equipment, which is of an ultra-thin type that vibrates in a direction that is easily felt by the body and has substantially the same shape as a lithium battery. To do. Another object of the present invention is to provide an inexpensive vibration actuator for portable equipment, which has a simple structure and drive circuit.

[0009]

[Means for Solving the Problems]

(First Invention) In order to achieve the above object, the vibration actuator for a portable device of the present invention has an ultra-thin cylindrical shape that gives vibration in the thickness direction, and is fixed to the upper lid 15 and A core member 18 having core-wound driving and position detecting air-core coils 16 and 16 ', and a protrusion 18' that goes in and out of the air-core coil, and has a lower portion also serving as a lower yoke. A permanent magnet 20 provided on a lower yoke of the core member 18, an upper yoke 21 provided on an upper portion of the permanent magnet 20, and the core member 18
The leaf spring member 17 is attached only to the center of the lower surface of the plate, and the center of the leaf spring member 17 can vibrate in the thickness direction.
And a cylindrical case 11 for accommodating a core member 18 to which a leaf spring member 17 is attached and which is covered by the upper lid 15 to which the air-core coils 16 and 16 'are attached.

(Second Invention) The leaf spring member 17 in the vibration actuator for portable equipment of the present invention has a plurality of slits 171, 172, 173 between the outer peripheral portion and the central portion so that the leaf spring member 17 can vibrate in the thickness direction. Is formed.

(Third Invention) The leaf spring member 17 in the vibration actuator for portable equipment of the present invention has a plurality of slits 171, 172, 173 between the outer peripheral portion and the central portion so that the leaf spring member 17 can vibrate in the thickness direction. Is formed in a substantially arc shape, and each slit 171, 172, 173 is formed so as to overlap between the outer peripheral portion and the central portion.

(Fourth Invention) In the vibration actuator for portable equipment of the present invention, the vibration cycle is the slit 171
It is characterized in that it can be adjusted by the number and shape of 172 and 173. (Fifth Invention) The yoke 21 in the vibration actuator for portable equipment of the present invention is characterized in that it is bent from the upper surface of the permanent magnet 20 in the direction along the cylindrical projection 18 'of the core member 18.

(Sixth Invention) The core member 18 of the vibration actuator for portable equipment is characterized in that the lower yoke (21-2) is attached separately.

(Seventh Invention) The core member 18 in the vibration actuator for portable equipment of the present invention is the air-core coil 1 described above.
It is characterized in that it is composed of a cylindrical projection portion 18 ′ that goes in and out of the inside of 6 and 16 ′, and a circular flange portion 20 ″.

(Eighth Invention) The outer peripheral portion of the leaf spring member 17 in the vibration actuator for portable equipment of the present invention divides the case 11 into an upper lid 15 and a lower lid 15 ', and also forms a case 11 and a lower lid 15'. It is characterized by being fixed so as to be sandwiched between them.

(Ninth Invention) A vibration actuator for portable equipment of the present invention comprises a comparator 54 for comparing the voltage applied to the driving air core coil 16 and the voltage generated in the position detecting air core coil 16 '. (See Figure 5)
And a drive circuit 51 for the vibration actuator, which is composed of a switch means 53 for turning ON / OFF the power supplied to the drive air core coil 16 by the output of the comparator 54.

[0017]

[Work]

(First Invention) The applicant has found that when an actuator for a mobile device is vibrated in a direction perpendicular to the surface of the body of a person carrying the device, the sensitivity is good and information is accurately transmitted.
In addition, the applicant of the present invention has an ultra-thin shape that is almost the same as a lithium battery
We succeeded in developing a cylindrical vibration actuator for mobile devices. That is, an ultra-thin cylindrical vibration actuator for portable devices has a protrusion inside the air-core coil for driving and position detection fixed to the upper lid, and a spring capable of vertical vibration only in the center of the lower surface. The core member to which the member is attached can be moved in and out. Then, the core member is moved into the air-core coil based on the force generated by the magnetic field of the permanent magnet provided on the upper part, the magnetic field of the yoke, and the magnetic field generated when the current is supplied to the driving air-core coil. Moving. Further, the core member can effectively utilize the magnetic field generated by the circular flange on the lower side also serving as the lower yoke.

Since the leaf spring member attached only to the central portion of the lower surface of the core member is fixed to the cylindrical case only at its outer peripheral portion, it moves in the direction perpendicular to the surface of the wearer's body. After that, the position detecting air-core coil generates a signal for stopping the supply of the current to the driving air-core coil by detecting the movement of the core member. When the supply of current to the driving air core coil is cut off, the leaf spring member
It returns to its original position by the force of the spring member. Next, after the current is supplied to the driving air-core coil in the same manner as described above, it moves in the same direction as described above. In this way, the vibration actuator for portable equipment generates vibration in a direction perpendicular to the body of the wearer. Further, the air-core coil, the core member, the permanent magnet, the leaf spring member and the like are housed by the upper lid and the cylindrical case to form a vibration actuator for a button-shaped ultra-thin portable device.

(Second Invention) In the leaf spring member of the present invention, a plurality of slits are formed between the outer peripheral portion and the central portion so as to vibrate in the thickness direction. The slit is located in the middle between the outer peripheral portion and the central portion of the leaf spring member, and for example, a large number of slits are provided along the outer periphery, and the positions of the start end and the end thereof are changed for each slit to form multiple layers. Is also formed. In the leaf spring member having such a plurality of slits, since the outer peripheral portion fixed to the cylindrical case and the central portion adhered to the core member move in different directions, vibration in a direction perpendicular to the wearer's body is generated. Can be generated.

(Third Invention) In the leaf spring member of the present invention, a plurality of substantially arcuate slits are formed between the outer peripheral portion and the central portion so as to vibrate in the thickness direction. The slit is located in the middle between the outer peripheral portion and the central portion of the leaf spring member, and for example, a large number of arc-shaped slits are provided along the outer periphery, and the position from the center point of the start end and the end thereof is determined for each slit. It is formed so that it can be changed and overlapped. The leaf spring member having such a plurality of arcuate slits can be easily moved in different directions between the outer peripheral portion fixed to the cylindrical case and the central portion adhered to the core member, so that It is possible to efficiently generate the vibration in the perpendicular direction.

(Fourth Invention) The vibration cycle of the vibration actuator for portable equipment according to the present invention is determined by the weight of the core member, the permanent magnet, the yoke, the material and the thickness of the leaf spring member. Besides, it can be adjusted by the number and shape of the slits. Therefore, the weight of the core member, the permanent magnet, the yoke, the material and the thickness of the leaf spring member, and the like are often inevitably determined in terms of design. However, since the number and shape of the slits have a lot of room for selection, the vibration cycle of the vibration actuator for portable equipment is adjusted by adjusting these.

(Fifth Invention) The yoke provided on the permanent magnet of the present invention covers the upper surface and the side surface of the permanent magnet, and is bent in the direction along the cylindrical projection of the core member. Therefore, the magnetic field from the air-core coil is efficiently generated through the core member and the yoke.

(Sixth Invention) In the core member of the present invention, the lower yoke can be provided as a separate body on the flange portion that is continuously provided on the cylindrical protrusion. The separate lower yoke makes the generated magnetic field efficient and facilitates the manufacture of the core member.

(Seventh Invention) Since the core member of the present invention is composed of the cylindrical projection portion that goes in and out of the air-core coil and the circular flange portion, the magnetic flux generated from the air-core coil can easily pass therethrough. Are configured.

(Eighth Invention) The case of the present invention is formed in a cylindrical shape, and is formed in an ultrathin cylindrical shape by the upper lid and the lower lid. Then, when assembling the vibration actuator for a mobile device, the leaf spring member is fixed so as to be sandwiched between the case and the lower lid. As a result, the case of the above-mentioned vibration actuator for mobile devices is easy to manufacture and assemble.

(Ninth Invention) The voltage applied to the driving air-core coil and the voltage generated in the position-detecting air-core coil are input to the comparator and compared with each other.
The output of the comparator is supplied to switch means for turning on / off the electric power supplied to the driving air core coil,
The drive circuit efficiently vibrates the vibration actuator.

[0027]

EXAMPLE An example of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of an embodiment of the present invention. FIG. 2 is an external view of a vibration actuator for a mobile device according to the present invention. In FIG. 1, a case 11
Is formed into a bottomed cylindrical shape having a first step portion 12 and a second step portion 13, and a lead wire insertion hole 14 described later on its side portion. As shown in FIG. 2, the case 11 has an outer diameter dimension that is substantially the same as that of the lithium battery. Further, in the case 11, the upper lid 15 is locked to the second step portion 13 and is hermetically sealed.

A drive air core coil 16 and a position detecting air core coil 16 '(hereinafter sometimes simply referred to as air core coil 16) are attached to the central portion of the lower surface of the upper lid 15. The air-core coil 16 is the case 1
It is connected to the power supply and the drive circuit from the outside of 1 via the lead wire 22. The leaf spring 17 has a slit to be described later, and after the outer peripheral portion is placed on the first step portion 12 of the case 11, for example, is fixed by a retaining ring 12 '. The core member 18 has a cylindrical protrusion 18 'at the center.
And has a circular flange portion 20 ″ on its periphery, which is fixed only to the lower side of the central portion thereof with the leaf spring 17 by spot welding or a strong adhesive 19, for example.

A circular flange portion 20 "of the core member 18
For example, a permanent magnet 20 having a plurality of magnetic poles in a ring shape is attached by an adhesive 20 ', for example. It is also possible to provide a plurality of permanent magnets instead of forming a ring shape. In addition, the ring-shaped permanent magnet 2
The ring-shaped yoke 21 having an L-shaped cross section is provided on the adhesive 2
It is attached by 1 '. Further, the core member 1
The cylindrical protrusion 18 ′ of 8 is sized so as to be movable inside the air-core coil 16. That is, the core member 1
8, the ring-shaped permanent magnet 20 and the yoke 21 constitute a mover. Further, in the core member 18, the circular flange 20 ″ also serves as the lower yoke. The core member 8 and the spring member 19 are spot-welded only on the lower side 19 of the central portion thereof. It is advisable to leave a slight space in order to facilitate vibration.

FIG. 3A shows another embodiment of the present invention, which is an explanatory view for making the assembly easy to understand. (B) is a view of the leaf spring, the core member, the permanent magnet, and the yoke as seen from above. 3 is different from FIG. 1 in that the leaf spring 1
7 fixing means. Case 11 in FIG.
Is configured to be divided into an upper lid 15 and a lower lid 15 '. Therefore, the leaf spring 17 is fixed so as to be sandwiched between the protrusion 13 ′ of the case 11 and the first step portion 12 of the lower lid 15 ′. This facilitates the production of the case 11 and the lower lid 15 'and the assembly with other parts.

FIG. 4A is a view for explaining an embodiment of the leaf spring of the present invention. FIG. 4B is a diagram for explaining another embodiment of the vibration actuator. Figure 4 (a)
In the above, a plurality of slits 171 to 173 are provided in the leaf spring 17 whose outer peripheral portion is fixed to the case 11. Then, in FIG. 4A, the two-dot chain line 19 shown represents the bonding range between the leaf spring 17 and the core member 18. As described above, the leaf spring 17 has an outer peripheral portion fixed to the case 11 and a central portion bonded to the back side of the cylindrical protrusion of the core member 18. The leaf spring 17 is configured to vibrate in the thickness direction by the slits 171 to 173.

The slit 171 is formed, for example, so that the position near the outer peripheral portion is the starting end and the end is the central portion. The slit 172 is formed, for example, such that the position close to the outer peripheral portion is the starting end and the end is approaching the central portion, and the starting end is the slit 171.
Are formed so as to overlap with each other between the terminal end of the plate spring, the central part of the leaf spring 17, and the outer peripheral part. The slit 173 is formed in the same manner as the slit 171 and the slit 172 at the position where the start end and the end end overlap with each other. Further, by changing the number and shape of each of the slits 171 to 173, it is possible to change the vibration cycle of the vibration actuator for portable equipment.

In FIG. 4B, what is different from FIG. 1 is the shape of the cylindrical protrusion and the yoke. For example, the cylindrical protrusion 18 ′ has a shape considerably smaller than the diameter of the air-core coil 16. In addition, the cylindrical protrusion 1
At the bottom of 8 ', there is a small circular flange 20 ",
A ring-shaped lower yoke 21 is provided on the circular flange portion 20 ″.
-2 is placed. The ring-shaped permanent magnet 20 shown in FIG. 4B is attached to the ring-shaped lower yoke 21-2. Further, the ring-shaped lower yoke 21-2 reaches the portion in contact with the end of the cylindrical protrusion 18 '. Such a ring-shaped lower yoke 21-2 has a cylindrical protrusion 18 'smaller than that in FIG.
Even in this case, the generated magnetic field is efficiently used in cooperation with the upper yoke 21-1.

FIG. 5 is a diagram for explaining a drive circuit for driving the vibration actuator for portable equipment of the present invention. In FIG. 5, the drive circuit 51 includes a drive air-core coil 16 for vibrating the core member 18, a position-detection air-core coil 16 ′ for detecting the position of the core member 18, and a power supply for the drive air-core coil 16. 52, for example, a transistor 53 for connecting a lithium battery, and an electromotive force generated in the position detecting air-core coil 16 ′ to one terminal, and the voltage of the driving air-core coil 16 is fed through a feedback resistor Rf and a resistor Ra. And a comparator 54 which inputs to the other terminal respectively, and a comparator 5
It is composed of a base resistor Rb for applying the output of 4 to the base of the transistor 53, and a power switch 55 for supplying a current to the driving air core coil 16.

When the power supply 52 is turned on by the power switch 55, a current flows through the driving air core coil 16. A magnetic field is generated in the direction of the arrow B in the drawing for the current flowing through the driving air-core coil 16 by Fleming's law. This magnetic field attracts the core member 18, the permanent magnet 20, and the yoke 21 in the direction of arrow A shown in FIG. 1 by the permanent magnet 20. At the same time, the position-detecting air-core coil 16 'has a voltage based on the detected current applied to the negative terminal of the comparator 54. The voltage at the time of driving is applied to the plus terminal of the comparator 54.

In such a state, in the position detecting air-core coil 16 ', the core member 18 has the air-core coils 16, 1
When it is detected that it has moved into 6 ', this detected voltage is input to one terminal of the comparator 54. As for the voltage input to the other side of the comparator 54, the voltage applied to the driving air core coil 16 is fed back by the feedback resistor Rf. The output voltage of the comparator 54 at this time is the transistor 5 provided between the driving air-core coil 16 and the power supply 52.
It works so that 3 is turned off. As a result, when no current flows in the driving air core coil 16, the core member 18 and the like are
The restoring force of the leaf spring 17 acts in the direction of arrow B shown in FIG. 1, returns to the original position, and becomes the initial state. A reciprocating motion is performed by repeating this.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. And
Various design changes can be made without departing from the present invention described in the claims. For example, in the leaf spring described in the embodiment, three arc-shaped slits are formed, but the shape is not limited to the shape and the number of slits, and when the outer peripheral portion is fixed, the center portion is thick. It only needs to be able to move in the direction. Also, in the embodiment,
The material of the spring member, the permanent magnet and the like is not particularly described, but any known material can be adopted. Similarly, the drive circuit is not limited to the embodiment and can be replaced with a circuit component having an equivalent function.

Further, as the core member, the lower yoke may be formed in a dish shape in section, a cylindrical core member may be attached to the dish-shaped central concave portion, and a ring-shaped permanent magnet may be attached to the flange portion of the dish. In addition, although spot welding or an adhesive agent is used for attaching each member in the embodiments, similar means can be used for assembling a case or the like. Further, the attachment means of each part can be replaced with a well-known fixing means other than the above means.

[0039]

According to the present invention, since the vibration actuator for portable equipment can be manufactured to be ultra-thin, the vibration actuator can be used in the information transmission device such as a card type pager, a wristwatch, a mobile phone, or a signal receiver for the blind. It is now possible to accurately transmit the vibration generated by the wearer to the wearer. According to the present invention, since the vibration direction of the core member is the thickness direction, the vibration is in the direction perpendicular to the surface of the body of the wearer, and the vibration of the vibration actuator for portable equipment is efficiently transmitted. According to the present invention, by combining a leaf spring member, a core member having a columnar protrusion, and an air-core coil for moving the columnar protrusion in and out, a vibration actuator for a portable device which is ultra-thin and approximately the same as a button battery I was able to get According to the present invention, each of the parts constituting the vibration actuator for a mobile device is formed into a simple shape, so that it is easy to assemble, the number of parts can be reduced, and the size and cost are reduced. According to the present invention, since the vibration actuator for portable equipment is reciprocated by the leaf spring member, the sliding portion is eliminated and mechanical abrasion or mechanical noise is completely generated as compared with the one using the rotating machine. No deterioration of parts.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an external view of a vibration actuator for a mobile device according to the present invention.

FIG. 3 (A) is another embodiment of the present invention, and is an explanatory view for making the assembly easier to understand. (B) is a view of the leaf spring, the core member, the permanent magnet, and the yoke as seen from above.

FIG. 4A is a diagram for explaining an embodiment of the leaf spring of the present invention. (B) is a diagram for explaining another embodiment of the vibration actuator.

FIG. 5 is a diagram for explaining a drive circuit for driving the vibration actuator for portable equipment of the present invention.

FIG. 6 is a diagram for explaining a flat-type vibration actuator in a conventional example.

[Explanation of symbols]

 11 ... Case 12 ... First step 12 '... Stop ring 13 ... Second step 14 ... Lead wire insertion hole 15 ... Top lid 16 ... Air core coil 17 ...・ Flat spring 18 ... Core member 18 '... Cylindrical protrusion 19 ... Adhesive 20 ... Permanent magnet 20' ... Adhesive 20 "... Circular flange 21 ... Yoke 21 '. Adhesive 21-1 ... Upper yoke 21-2 ... Ring-shaped lower yoke 22 ... Lead wire 25 ... Vibration actuator for mobile equipment 51 ... Drive circuit 52 ... Power source 53 ... -Switch means (transistor) 54 ... Comparator 55 ... Switches 171-173 ... Arc-shaped slit

Claims (9)

[Claims] 1. An ultra-thin cylindrical vibration actuator for portable equipment, which vibrates in the thickness direction, is fixed to an upper lid and is coaxially wound around a driving and position detecting air core. A core member having a coil, a protrusion that goes in and out of the air-core coil, and a lower portion also serves as a lower yoke; a permanent magnet provided on the lower yoke of the core member; and an upper portion of the permanent magnet. The upper yoke provided, the leaf spring member that is attached only to the central portion of the lower surface of the core member, and the central portion can vibrate in the thickness direction, and the outer peripheral portion of the leaf spring member are fixed. A portable device, comprising: a cylindrical case that houses a core member to which a magnet and a leaf spring member are attached and that is covered by the upper lid to which an air-core coil is attached. Vibration actuator. 2. The portable device according to claim 1, wherein the leaf spring member has a plurality of slits formed between an outer peripheral portion and a central portion so that the leaf spring member can vibrate in the thickness direction. Vibration actuator. 3. The leaf spring member has a plurality of slits formed in a substantially arc shape between an outer peripheral portion and a central portion so that the leaf spring member can vibrate in the thickness direction, and each slit forms an outer peripheral portion. The vibration actuator for a mobile device according to claim 1, wherein the vibration actuator is formed so as to overlap with the central portion. 4. The vibration actuator for a mobile device according to claim 1, wherein the vibration cycle of the vibration actuator for the mobile device can be adjusted by the number and shape of the slits. 5. The vibration actuator for a portable device according to claim 1, wherein the yoke is bent from an upper surface of the permanent magnet in a direction along a cylindrical protrusion of the core member. 6. The vibration actuator for a portable device according to claim 1, wherein a lower yoke of the core member is attached separately. 7. The vibration actuator for a portable device according to claim 1, wherein the core member is composed of a cylindrical projection portion that goes in and out of the air-core coil, and a circular flange portion. 8. The outer peripheral portion of the leaf spring member divides the case into an upper lid and a lower lid, and is fixed so as to be sandwiched between the case and the lower lid. Vibration actuator for mobile devices. 9. A comparator for respectively comparing a voltage applied to the driving air-core coil and a voltage generated in the position-detecting air-core coil, and is supplied to the driving air-core coil by the output of the comparator. Turn on the power
2. A drive circuit for a vibration actuator comprising switch means for switching on / off.
A vibration actuator for a portable device as described above.