JP2004341094A - Switching mechanism and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize the constitution, to reduce power consumption and to fix the moving member at an appropriate angle in a switching mechanism for a moving member. <P>SOLUTION: The switching mechanism is provided with: a moving member 1 which is made movable along a prescribed track; two wire type shape memory alloys WA and WB which contract in directions opposite to each other in accordance with power supply to the respective alloys; an arm 3 which amplifies and transmits the extension/contraction action of the two wire type shape memory alloys WA and WB to the moving member 1; and magnets M, MA and MB for fixing the moving member 1 at a prescribed position when the moving member 1 moves along the prescribed track through the arm 3. Further, an electronic device provided with the switching mechanism is described. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a switching mechanism for switching a fixed position of a movable member movably attached along a predetermined track, and an electronic device using the switching mechanism.
[0002]
[Prior art]
2. Description of the Related Art In recent years, many electronic devices including an imaging device, such as a notebook computer, a PDA (Personal Digital Assistant), and a mobile phone, have been developed. . In particular, when a small-sized image pickup device is incorporated in an electronic device, if optical components are miniaturized, performance degradation due to lens aberration or the like is likely to occur, and thus there is a limit to miniaturizing the lens itself. Therefore, simplification of the members holding the optical components and the driving mechanism is an important point.
[0003]
2. Description of the Related Art Conventionally, as a mechanism for switching the position of an optical component, for example, a filter or a lens, in an imaging apparatus, an arm is attached to a member to be moved and the arm is manually moved (for example, see Patent Document 1), and a motor is used. The thing which moves using as power is considered.
[0004]
[Patent Document 1]
JP 2003-75896 A
[Problems to be solved by the invention]
However, in order to manually drive the arm attached to the moving member as such a switching mechanism, it is necessary to provide a member (an arm or a holding frame) on the housing of the electronic device, and a projection appears on the housing. This hinders miniaturization and impairs the appearance. In addition, a configuration in which the motor can be used to drive the inside of the housing requires a space for accommodating the motor and increases the weight.
[0006]
[Means for Solving the Problems]
The present invention has been made to solve such a problem. That is, the present invention provides a moving member that can move along a predetermined trajectory, two contracting units that contract in opposite directions by energizing each of them, and a moving member that amplifies the contracting operation of the two contracting units. The switching mechanism includes a mechanical amplifier for transmitting the moving member to the moving member and a suction unit for fixing the moving member at a predetermined position when the moving member moves along a predetermined path via the mechanical amplifier. In addition, it is an electronic device provided with this switching mechanism.
[0007]
In the present invention as described above, since the moving member is moved along the predetermined trajectory, the moving member can be moved by an electric switch because the contracting means contracts by energization. Further, since the contraction operation by the contraction means is transmitted to the moving member by the mechanical amplifier, the moving member can be moved even by a slight contraction operation by the contraction means. In addition, when the moving member comes to a predetermined position by the driving of the contracting unit, the moving unit is suction-fixed to the position by the suction unit, so that the position can be fixed accurately.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a switching mechanism according to the first embodiment. That is, the switching mechanism according to the present embodiment is a mechanism that switches the fixed position by linearly moving the moving member 1 along the shaft 2.
[0009]
As shown in FIG. 1, the switching mechanism according to the present embodiment is formed by three magnets MA, MB, M0 (which may be integrally formed) and a yoke Y2 as a fixed side, and a shaft 2 fixed as a movable side. (Which may be formed integrally with the magnet M and the yoke Y1), an arm 3 having a rotation center connected to the moving member 1 by an engaging portion 11, and the arm 3 Two wire-type shape memory alloys WA, WB, and electrodes a, b, A, which support the ends of the wire-type shape memory alloys WA, WB, which are mounted in the directions facing each other through the holes H of B (including a current-carrying part).
[0010]
Of the three magnets MA, MB, and M0 on the fixed side, the magnets MA and MB at both ends have a polar arrangement that attracts the magnet M on the moving member 1 side, and the magnet M0 in the middle has a polar arrangement that repels. I have. With such a configuration, the magnets MA and MB at both ends act as a suction unit, and the middle magnet M0 acts as a neutral position avoiding magnet, so that the moving member 1 can be prevented from stopping at the neutral position during the movement. become. The movable and fixed yokes Y1 and Y2 serve to close the magnetic circuit.
[0011]
The arm 3 is connected to the engaging portion 11 of the moving member 1 with a small clearance as shown in FIG. 3, so that the moving member 1 can move linearly along the shaft 2 by the rotation of the arm 3. . Further, the arm 3 is supported by a fixed shaft 21 for the center of rotation as shown in FIG. 4 and rotates about the same, and has a hole H at the end opposite to the moving member 1. , Two wire-shaped shape memory alloys WA and WB pass therethrough. At this time, holes H are separately provided and mounted so that the wire type shape memory alloys WA and WB do not contact each other.
[0012]
The ends of the respective wire-type shape memory alloys WA and WB are supported (fixed) by two fixed electrodes a and b, one side of which is common to the ground electrode GND, and the other side of each. Are connected to the current-carrying electrodes A and B, which are used to input current when current is applied.
[0013]
In the present embodiment, the length ratio (arm ratio) of the length of the engagement portion 11 on the moving member 1 side to the fixed portion (hole H) on the wire type shape memory alloy WA or WB side from the center of rotation of the arm 3 is doubled. The mechanical amplifier is such that the amount of shrinkage (about 4%) of the alloy when energized is doubled. The connection of the wire type shape memory alloys WA and WB to the fixed electrodes a and b is fixed by caulking at the caulking portion as shown in FIG.
[0014]
Next, the operation of the switching mechanism according to the present embodiment will be described. First, at the position shown in FIG. 1, a current iA is applied from the conducting electrode A to the wire-type shape memory alloy, whereby the wire-type shape memory alloy WA contracts in the direction of arrow FA in the figure, and the lower end side of the arm 3 in the figure is fixed. It is drawn to the electrode a side. Accordingly, the upper end side of the arm 3 in the figure moves to the right side in the figure, and the moving member 1 moves along the shaft 2 to the right side in the figure (arrow GA).
[0015]
After the moving member 1 moves, it is drawn to the right side in the figure by the repulsion of the magnet M0 on the fixed side and the suction of the magnet MB on the right side in the figure, and stops using the wall as a stopper (see FIG. 5). Even if the current iA from the conductive electrode A to the wire-type shape memory alloy WA is stopped in this state, the position of the moving member 1 is fixed by the attraction force between the magnet M provided on the moving member 1 and the fixed-side magnet MB. Can be maintained.
[0016]
Next, the operation on the opposite side will be described. At the position shown in FIG. 5, a current iB flows from the energizing electrode B to the wire-type shape memory alloy WB, whereby the wire-type shape memory alloy WB contracts in the direction of arrow FB in the figure. The lower end of the arm 3 in the figure is drawn toward the fixed electrode b. Accordingly, the upper end side of the arm 3 in the figure moves to the left side in the figure, and the moving member moves to the left side in the figure (GB in the figure) along the shaft.
[0017]
After the moving member 1 moves, it is pulled to the left side in the figure by the repulsion of the magnet M0 on the fixed side and the suction of the magnet MA on the left side in the figure, and stops using the wall as a stopper (see FIG. 1). In this state, even if the current iB from the energizing electrode B to the wire-type shape memory alloy is stopped, the position of the moving member 1 is fixed by the attraction between the magnet M provided on the moving member 1 and the fixed magnet MA. Will be able to maintain it.
[0018]
Therefore, by switching the energization of the currents iA and iB from the current-carrying electrodes A and B to the wire-type shape memory alloys WA and BWB in this manner, the movement is performed by the contraction force of the energized wire-type shape memory alloys WA and WB. The fixing position of the member 1 can be switched. Thus, the switching mechanism can be realized with a compact configuration without using a driving source such as a motor. Further, after the fixed position is switched, the fixed position can be maintained by the attraction force of the magnet even when the energization is released, and power consumption can be reduced.
[0019]
Next, a second embodiment will be described. FIG. 6 is a schematic diagram illustrating a switching mechanism according to the second embodiment. The switching mechanism according to this embodiment switches the position of the moving member 1 that rotates. That is, as shown in FIG. 6, the fixed side is formed by three magnets MA, MB, and M0 (which may be integrally formed) and the yoke Y2, and the moving member 1 (the magnet M and the yoke Y1) that rotates and moves on the movable side. The movable member 1 is attached to the end, an arm 3 having a center of rotation, and two wire types mounted in opposite directions through respective holes H of the arm 3. The shape memory alloys WA, WB, and the electrodes a, b, A, and B (including the current-carrying portions) that support the ends of the wire-type shape memory alloys WA, WB are included.
[0020]
The three magnets MA, MB, and M0 on the fixed side are arranged around the trajectory of the rotational movement of the moving member 1, and the magnets MA and MB at both ends are polar arrangements that attract the magnet M on the moving member 1 side. The center magnet M0 has a polar arrangement that repels. With such a configuration, the magnets MA and MB at both ends act as a suction unit, and the middle magnet M0 acts as a neutral position avoiding magnet, so that the moving member 1 can be prevented from stopping at the neutral position during the movement. become. The movable and fixed yokes Y1 and Y2 serve to close the magnetic circuit.
[0021]
The moving member 1 is attached to one end of the arm 3, and can rotate and move along a predetermined arc by rotation of the arm 3. The arm 3 is supported by a fixed shaft 21 for the center of rotation, rotates about the same, and has a hole H at the end opposite to the moving member 1, and has two wire-type shape memories therein. Alloys WA and WB pass. At this time, holes H are separately provided and mounted so that the wire type shape memory alloys WA and WB do not contact each other.
[0022]
The ends of the respective wire-type shape memory alloys WA and WB are supported (fixed) by two fixed electrodes a and b, one side of which is common to the ground electrode GND, and the other side of each. Are connected to the current-carrying electrodes A and B, which are used to input current when current is applied.
[0023]
In the present embodiment, the length ratio (arm ratio) of the connection end of the moving member 1 from the center of rotation of the arm 3 to the fixed portion (hole H) on the wire-type shape memory alloy WA, WB side is doubled. The mechanical amplifier is such that the amount of shrinkage (about 4%) of the alloy when energized is doubled. The connection between the wire type shape memory alloys WA, WB and the fixed electrodes A, B is fixed by caulking at a caulking portion as shown in FIG.
[0024]
Next, the operation of the switching mechanism according to the present embodiment will be described. First, at the position shown in FIG. 6, the current iA flows from the energizing electrode A to the wire-type shape memory alloy WA, whereby the wire-type shape memory alloy WA contracts in the direction of the arrow FA in the figure, and the lower end side of the arm 3 in the figure is fixed. It is drawn to the electrode a side. Accordingly, the upper end side of the arm 3 in the figure moves to the right side in the figure, and the moving member 1 moves in an arc toward the electrode B (arrow SA in the figure).
[0025]
After the moving member 1 moves, it is drawn to the right side in the figure by the repulsion of the magnet M0 on the fixed side and the suction of the magnet MB on the right side in the figure, and stops using the wall as a stopper (see FIG. 7). Even if the current iA from the conductive electrode A to the wire-type shape memory alloy WA is stopped in this state, the position of the moving member 1 is fixed by the attraction force between the magnet M provided on the moving member 1 and the fixed-side magnet MB. Can be maintained.
[0026]
Next, the operation on the opposite side will be described. At the position shown in FIG. 7, a current iB flows from the energizing electrode B to the wire-type shape memory alloy WB, whereby the wire-type shape memory alloy WB contracts in the direction of arrow FA in the figure. The lower end of the arm 3 in the figure is drawn toward the fixed electrode b. Accordingly, the upper end side of the arm 3 in the figure moves to the left side in the figure, and the moving member 1 moves in an arc toward the electrode A (arrow SB in the figure).
[0027]
After the moving member 1 moves, it is drawn to the left side in the figure by the repulsion of the magnet M0 on the fixed side and the suction of the magnet MA on the left side in the figure, and stops using the wall as a stopper (see FIG. 6). Even if the current iB from the energizing electrode B to the wire-type shape memory alloy WB is stopped in this state, the position of the moving member 1 is fixed by the attraction force between the magnet M provided on the moving member 1 and the fixed magnet MA. Can be maintained.
[0028]
Therefore, when the currents iA and iB are supplied to the wire-shaped shape memory alloys WA and WB from the current-carrying electrodes A and B, the wire-shaped shape memory alloys WA and WB move along a circular locus due to the contraction force of the wire-shaped shape memory alloys WA and WB. The fixing position of the member 1 can be switched. Thus, the switching mechanism can be realized with a compact configuration without using a driving source such as a motor. Further, after the fixed position is switched, the fixed position can be maintained by the attraction force of the magnet even when the energization is released, and power consumption can be reduced.
[0029]
The switching mechanism described above is suitable for use in electronic equipment equipped with an imaging device, such as a digital still camera, a notebook computer, a PDA, and a mobile phone for switching the movement of optical components. For example, the present invention can be used for a mechanism in which a movable member is used as an optical filter to switch ON / OFF of an optical filter or to move a position of an optical lens. This makes it possible to reduce the size and power consumption of an electronic device including the switching mechanism.
[0030]
【The invention's effect】
As described above, the present invention has the following effects. That is, it is possible to reduce the size and thickness of the mechanism for switching the position of the predetermined moving member. Further, power consumption, cost reduction and high reliability can be achieved as compared with the case where a motor is used as a power source. This also makes it possible to reduce the size and thickness of the electronic device. In addition, the switching mechanism can be incorporated inside the housing, so that the appearance of the housing is not impaired, and the degree of freedom in housing design can be increased.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a switching mechanism according to a first embodiment.
FIG. 2 is a schematic diagram illustrating connection between a wire-type shape memory alloy and a fixed electrode.
FIG. 3 is a schematic diagram illustrating connection between an arm and a moving member.
FIG. 4 is a schematic diagram illustrating connection between an arm and a rotation center shaft.
FIG. 5 is a schematic diagram illustrating another fixed position of the switching mechanism according to the first embodiment.
FIG. 6 is a schematic diagram illustrating a switching mechanism according to a second embodiment.
FIG. 7 is a schematic diagram illustrating another fixed position of the switching mechanism according to the first embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Moving member, 2 ... Shaft, 3 ... Arm, 10 ... Bearing part, 11 ... Engagement part, M ... Magnet, MA ... Magnet, MB ... Magnet, WA ... Wire shape memory alloy, WB ... Wire shape memory alloy

Claims (7)

A movable member movable along a predetermined trajectory,
Two contracting means that contract in opposite directions by energizing each;
A mechanical amplifier that amplifies the contraction operation by the two contraction means and transmits the amplified contraction operation to the moving member;
A switching mechanism, comprising: suction means for fixing the moving member at a predetermined position when the moving member moves along a predetermined trajectory via the mechanical amplifier. 2. The switching mechanism according to claim 1, wherein said shrinking means is made of a shape memory alloy. The mechanical amplifier includes an arm rotatably provided around a support shaft,
At one end of the arm, the two retracting means are connected to move one end of the arm in the opposite direction to each other,
The switching mechanism according to claim 1, wherein the moving member is attached to the other end of the arm. 2. The switching mechanism according to claim 1, wherein said suction means performs suction by a magnet. The switching mechanism according to claim 1, wherein the suction unit includes a plurality of magnets arranged corresponding to fixed positions of the moving member. 2. The switching mechanism according to claim 1, wherein a neutral position avoiding magnet for avoiding fixing the position of the moving member is provided between the plurality of magnets in the attracting means. In an electronic device including a switching mechanism for switching a fixed position of the moving member,
The switching mechanism includes:
Two contracting means that contract in opposite directions by energizing each;
A mechanical amplifier that amplifies the contraction operation by the two contraction means and transmits the amplified contraction operation to the moving member;
An electronic device, comprising: suction means for fixing the moving member at a predetermined position when the moving member moves along a predetermined trajectory via the mechanical amplifier.

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