JP2001144689A - Optical axis correction device and manufacturing method for voice coil motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical axis correction device that corrects an optical axis in an optical space transmitter that enhances the adhesiveness between a heat sink and a coil placed on a voice coil motor being a drive mechanism section of a mirror so as to enhance the heat dissipation performance of the heat sink. SOLUTION: A resin-made thermal conduction sheet 18Yf touches with a winding face of a coil 18Yb, a heat sink 18Ye is fixed on it so as to support the thermal conduction sheet 18Yf, then the thermal conduction sheet 18Yf is in contact with copper wires 181Yb so as to embrace them due to its flexibility. Thus, the thermal conductivity of heat generated from the coil 18Yb and conducted to the heat sink 18Ye can be enhanced so as to enhance the heat dissipation performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis correcting apparatus for correcting an optical axis in an optical space transmission apparatus, and more particularly to an optical axis correcting apparatus for correcting an optical axis by controlling a reflection angle of a mirror. About. Further, the present invention relates to an apparatus for manufacturing a voice coil motor used in an optical axis correction device.

[0002]

2. Description of the Related Art In recent years, research on the practical use of spatial communication using light has been actively conducted due to the shortage of radio wave resources and complicated procedures for setting up a wireless or wired communication line. ing. However, as for the optical space transmission device over a long distance of up to kilometers, a device having sufficient performance has not yet been obtained.

In particular, in such communication using light, it is necessary that the optical axes of the transmitting side and the receiving side always coincide to perform accurate beam transmission and reception. However, the optical system is affected by external factors such as wind, vibrations generated inside the device, and furthermore, changes in temperature, etc., causing a shift in the optical axis.
In long-distance communication, a slight deviation of the optical axis also hinders communication, so that it is necessary to constantly correct the optical axis.

[0004] In order to respond to such a request, the applicant of the present invention has disclosed a title of the invention as an optical axis correcting device in Japanese Patent Application No. 11-247.
No. 283 has been filed. FIG. 8 shows a schematic configuration of an optical system portion of an optical space transmission device capable of performing bidirectional optical communication, including the optical axis correction device described above.

In this optical space transmission apparatus, the beam of the light emitting element 1 modulated based on the transmission signal is converted into parallel light by the lens 2 and is incident on the beam splitter 3a.
Here, the reflected beam is reflected on the mirror 1 of the optical axis correcting device 10.
2, the reflected light is incident on a concave lens 4 on the light input / output side, and the beam expanded by the lens 4 is converted into parallel light by a lens 5 that constitutes a main lens unit together with the lens 4 and transmitted to a destination. Output to the optical space transmission device.

On the other hand, the beam received from the other party is received by the lens 5, converted into parallel light by the lens 4, and then enters the mirror 12 of the optical axis correction device 10. The reflected light passes through the beam splitter 3a and passes through the beam splitter 3b
Is incident on. The beam splitter 3b distributes the incident beam to a position detection side and a reception side. Of these, the beam distributed to the position detection side is condensed by the lens 6 and enters the position detection sensor 7. Position detection sensor 7
Detects the position of the incident light and transmits the detection signal to a control circuit (not shown). On the control circuit side, angle control described later is performed based on the detection signal.

On the other hand, the beam allocated to the receiving side is
The light is condensed by the lens 8 and enters the light receiving element 9. The light receiving element 9 converts the incident beam into an electric signal and sends it to a receiving circuit (not shown) as a received signal. On the receiving circuit side, the received signal is demodulated and restored to the original data.

In this optical system, the optical axis correcting device 10 operates the mirror 1 so that the reflected light of the beam incident on the mirror 12 from the lens 4 can be accurately incident on the beam splitter 3a.
Adjust the angle of 2.

FIG. 9 is a plan view of a conventional optical axis correction device. The optical axis correction device 10 converts an input beam into a mirror 12
And the angle of the mirror 12 is changed to correct the optical axis of the reflected light and make it incident on the input element.

The optical axis correcting device 10 has a structure in which a biaxial spring 11 is mounted on the upper surface of a frame described later.
The biaxial spring 11 is a thin elastic disk-shaped member and has three coaxial rings 111, 112, and 113. The outermost outer ring 111 is fixed to the frame. A gap is provided between the outer ring 111 and the intermediate ring 112, and the intermediate ring 112 is connected to the outer ring 111 by a Y-axis bridge 11y in a rotatable manner. Thus, the intermediate ring 112 is rotatable around the Y axis with respect to the outer ring 111. Similarly, a gap is provided between the innermost inner ring 113 and the intermediate ring 112,
The inner ring 113 is connected to the intermediate ring 112 by an X-axis bridge 11x so as to be rotatable. As a result, the inner ring 113 is
With respect to the X axis. The circular mirror 12 is fixed to the inner ring 113.

FIG. 10 is a sectional view taken along the line GG of FIG. As described above, the biaxial spring 11 is connected to the frame 1
3 is fixed to the upper surface. A mirror holder 14 is fixed to the lower surface of the inner ring 113 and holds the mirror 12. At this time, the mirror 12 is mounted such that its reflection surface 12a coincides with the center plane of the plate thickness of the biaxial spring 11.

The base plate 1 is provided on the lower end surface of the frame 13.
5 is fixed, and a substrate 17 is fixed via an annular spacer 16. A drive mechanism 18 for rotating the mirror holder 14 is provided on the base plate 15. The drive mechanism 18 includes the mirror holder 14
X-axis drive mechanism 18X for rotating the X-axis around the X-axis, and Y
There are two Y-axis drive mechanism units 18Y that rotate about the axis, and two X-axis drive mechanism units 18X and Y-axis drive mechanism units 18Y each determine the intersection of the X-axis and the Y-axis, that is, the origin. They are provided at positions facing each other with a sandwich therebetween. However, in FIG. 10, the X-axis drive mechanism 1
One of 8X is not shown because it is on the near side of the drawing.

The Y-axis driving mechanism 18Y is a so-called moving magnet type voice coil motor, and mainly includes a bobbin 18Ya and a bobbin 1 fixed to the base plate 15.
A coil 18Yb wound around 8Ya, a yoke 18Yc fixed to the mirror holder 14, a magnet 18Yd fixed inside the yoke 18Yc, and a coil 18Yb
The heat sink 18Ye, which will be described later, is provided in close contact with the heat sink 18Ye. The optical axis correction device 10 controls the rotation of the mirror holder 14 about the Y axis by controlling the driving of the two Y axis drive mechanisms 18Y.

Similarly, the X-axis drive mechanism 18X is provided with the bobbin 1
8Xa, a coil 18Xb, a yoke 18Xc, and a magnet (not shown).
The rotation angle of the mirror holder 14 around the X axis is controlled. Similarly, a heat sink 18Xe (not shown) is provided on the coil 18Xb.

An X-axis angle sensor 19X and a Y-axis angle sensor 19Y are fixed on the base plate 15. In the optical axis correction device 10, based on the angle detection signals from the X axis angle sensor 19X and the Y axis angle sensor 19Y, the X axis driving mechanism 18X and the Y axis driving mechanism 18Y
And the angle of the reflection surface 12a of the mirror 12 is controlled. Thereby, the correction control of the optical axis is performed.

In the X-axis and Y-axis driving mechanisms, a driving force is generated by the magnetic field generated by the magnet and the current flowing through the coil, and the direction of the driving force is determined by the direction of the current flowing through the coil and by the magnitude of the current. The magnitude of the driving force is determined. When an electric current is applied to the coil, Joule heat is generated in accordance with the magnitude of the electric current, and the temperature of the coil rises, thereby increasing the resistance of the coil. Increasing the resistance of the coil results in a decrease in the current flowing through the coil, which reduces the driving force. In other words, when the temperature of the coil increases, the rotation angle of the mirror decreases due to the decrease in driving force,
The driving performance of the mirror is significantly deteriorated, such as a decrease in the rotation accuracy of the mirror and a decrease in the rotatable angle. Further, the temperature rise of the coil itself leads to a reduction in the life of the coil or damage to the coil.

Therefore, in the optical axis correction device 10, the X-axis drive mechanism 18X and the Y-axis drive mechanism 18Y respectively
Heat sinks 18Xe and 18Ye for releasing heat generated by the coils into the base plate 15 and air are attached.

FIG. 11 is a sectional view showing the attachment of the heat sink to the coil. Here, the heat sink 18Ye installed in the Y-axis drive mechanism 18Y will be described, but the heat sink 18Xe installed in the X-axis drive mechanism 18X has the same structure.

The heat sink 18Ye has an upper portion 180b of a thin plate of oxygen-free copper or pure aluminum, which is a non-magnetic metal having a high thermal conductivity, and the lower portion 180a is bent to be horizontal. The upper portion 180b of the heat sink 18Ye is bent so that the vertical portion 180b and the pair of tip portions 18
0c, the coil 18Yb sandwiched between the pair of magnets 18Yd is attached so as to be pressed against three sides except one side, and the lower part 180a is screwed to a metal base plate 15 (not shown) holding the coil. Have concluded.

Bobbin 1 on which coil 18Yb is wound
8Ya is made of resin, but since resin has lower thermal conductivity than metal, the heat generated in the coil 18Yb is less likely to be conducted to the base plate 15, so that the heat is transferred to the coil 18Yb.
And the temperature of the coil 18Yb increased. However, by attaching the heat sink 18Ye, the heat generated in the coil 18Yb causes the coil 18Yb
→ Heat sink 18Ye → Conducts in the order of base plate 15, and is finally radiated into the air. Therefore, even when a relatively large current flows, the temperature rise of the coil 18Yb when the heat generation and the heat radiation reach an equilibrium state can be suppressed.

Further, an example in which the adhesion between the heat sink and the coil is enhanced to improve the heat radiation efficiency will be described below. FIG. 12 shows a first example of a heat sink having improved adhesion to a coil.
(A) shows the structure of a conventional heat sink, and (b) shows the structure of a heat sink with improved adhesion.

The coil guide 181Ya provided on the bobbin 18Ya is formed larger than the winding dimension of the coil 18Yb in order to wind up the coil 18Yb to the end. When a heat sink is to be attached to the bobbin 18Ya, the heat sink 18 shown in FIG.
As shown in the H section of Yeb, the heat sink is fixed to the base plate, so that the shape becomes complicated and the adhesion between the coil and the heat sink is deteriorated.

On the other hand, in FIG. 12B, the coil guide 181Ya on the side where the heat sink 18Yec is mounted is shown.
b, a notch is provided in the I portion, and the coil guide 181Yab
The shape of the heat sink was simplified by molding a part of the lower part so as to be flush with the coil 18Yb. As a result, the adhesion between the coil and the heat sink is enhanced, and the rate of conduction of the generated heat to the base plate increases, so that the amount of heat radiation can be improved.

FIGS. 13A and 13B show a second example of a heat sink in which the adhesion to the coil is enhanced. FIG. 13A shows the shape of the heat sink, and FIG. 13B shows the structure of attaching the heat sink to the coil. The tip of the fin of the heat sink 18Yed in FIG. 13 is inclined inward so as to be narrower by about 0.5 mm to 1 mm with respect to the coil winding dimension W, and the fin spreads when attached to the coil, and according to the expanded dimension. The fin is brought into close contact with the coil by the elastic force acting on the fin. Thereby, even if there is some error in the winding dimension of the coil, the heat sink can be securely brought into close contact with the coil by utilizing the elastic force of the fin.

Further, as a method of further improving the heat radiation performance of the heat sink, a method of increasing the heat radiation amount to the air by increasing the area of the fins, or a method of increasing the heat radiation amount to the base plate by increasing the area of the contact portion with the base plate. There is a method to increase.

[0026]

In the voice coil motor of the optical axis correcting device described above, a heat sink is provided on the coil, but the coil and the heat sink are not always in close contact. FIGS. 14A and 14B are enlarged views of a contact portion between a copper wire of a coil and a heat sink. FIG. 14A shows a case of an array winding coil, and FIG. 14B shows a case of a coil having winding disturbance.

The heat sink 18Ye is a metal plate, and the coil is formed by winding a thin copper wire 181Yb. As shown in FIG. 14A, the surface of the coil copper wire 181Yb is ideally flat. If it is wound like
The copper wire 181Yb and the heat sink 18Ye are in contact with each other in a state close to wire contact. In the state where the surface of the coil is wavy as shown in FIG. 14B, there is a copper wire that does not contact the heat sink 18Ye.

In the case where a normal coil is wound in multiple layers, FIG.
It is rare that the winding surface becomes flat as in (a), and it is normal that the winding surface is wavy as shown in FIG. In such a situation, a layer of air with low thermal conductivity exists between the coil and the heat sink, preventing the flow of heat from the coil to the heat sink.

In the conventional method shown in FIG. 13 in which the fins of the heat sink are inclined inward to improve the adhesion to the coil by the elastic force of the fins, the adhesion can be improved to some extent. In addition to the problem of reduced heat transfer efficiency due to the air layer between the coil and the heat sink, when attaching the heat sink to the coil, the tips of the fins will rub the surface of the coil and damage the copper wire insulation film, and the coil will short-circuit. There was sometimes.

As described above, in the conventional optical axis correction device,
The challenge has been to further improve the heat radiation performance of the heat sink attached to the voice coil motor, and to improve the quality and reliability in assembling the coil and the heat sink.

The present invention has been made in view of such a point, and it is an object of the present invention to provide an optical axis correction device in which the heat radiation performance of a voice coil motor is improved. It is another object of the present invention to provide a method of manufacturing a voice coil motor having a simplified heat treatment process, easy adaptation to automation, and improved heat radiation performance.

[0032]

According to the present invention, there is provided an optical axis correcting apparatus for correcting an optical axis in an optical space transmission apparatus, comprising: a mirror for reflecting a laser beam; A mirror holding member for holding, a support member for rotatably supporting the mirror holding member about a first axis and a second axis on a plane parallel to the reflection surface of the mirror, and first and second mirrors for the mirror A magnet provided on the side of the mirror holding member that rotates independently around the axis of the coil, a coil for driving the magnet, a heat conductive sheet covering three surfaces around the coil, and a U-shaped coil through the heat conductive sheet A rotation mechanism portion having a heat sink covered with the other surface in close contact with the base surface; a rotation angle detection mechanism portion for detecting a rotation angle around each axis of the mirror; and first and second mirrors
And a rotation control means for controlling the rotation mechanism so that the rotation angles about the respective axes become the desired angles, respectively.

In such an optical axis correction device, since the heat conductive sheet is interposed between the coil of the voice coil motor and the heat sink, the heat conductivity from the coil to the heat sink increases, and the heat radiation performance of the heat sink improves. Thereby, the rotational drive control of the mirror is stabilized, and the power consumption of the voice coil motor can be reduced. Further, when attaching the heat sink to the coil, the copper wire of the coil is not damaged, and the quality and reliability of the coil are improved.

Further, according to the present invention, there is provided a voice coil motor having a heat sink disposed close to three surfaces around a coil for dissipating heat generated from the coil, and a heat conductive resin filled in a gap between the heat sink and the coil. In the manufacturing method, the side surface of the coil is adhered to the plate material, and the heat sink is arranged around the coil so that the end portion adheres to the plate material,
Injecting a gel-like heat conductive resin from a hole provided in a part of the heat sink, filling the gap between the plate material, the coil and the heat sink with the heat conductive resin, curing the heat conductive resin, and removing the plate material. A method for manufacturing a voice coil motor is provided.

In such a method of manufacturing a voice coil motor, a heat sink having a hole in a part thereof is used, a gel-like resin is injected from the hole, and the resin is filled in a gap between the coil and the heat sink, so that the heat radiation performance is improved. A voice coil motor with high quality and improved quality can be easily manufactured, and automation of the manufacturing process is facilitated.

[0036]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a plan view showing the optical axis correction device of the present invention. The optical axis correction device 10 makes the input beam incident on the mirror 12, changes the angle of the mirror 12,
This device corrects the optical axis of the reflected light and makes it incident on the input element. The basic structure is the same as that of the conventional example.

The optical axis correction device 10 has a structure in which a biaxial spring 11 is mounted on the upper surface of a frame 13 described later. The biaxial spring 11 is a thin disk-shaped member having elasticity and includes three coaxial rings 111, 112, 113.
have. The outermost outer ring 111 is the frame 1
It is fixed to 3. Outer ring 111 and intermediate ring 1
A gap is provided between the intermediate ring 11 and the intermediate ring 11.
Numeral 2 is connected to the outer ring 111 by a Y-axis bridge 11y in a rotatable state. This allows
The intermediate ring 112 is rotatable around the Y axis with respect to the outer ring 111.

A gap is also provided between the innermost inner ring 113 and the intermediate ring 112. Inner ring 1
13 is an intermediate ring 11 by an X-axis bridge 11x.
It is connected to 2 in a rotatable state. As a result, the inner ring 113 moves X with respect to the intermediate ring 112.
It is rotatable around an axis. The circular mirror 12 is fixed to the inner ring 113. FIG. 3 is a sectional view taken along the line DD in FIG. As described above, the biaxial spring 11 is fixed to the upper surface of the frame 13. On the lower surface of the inner ring 113, a mirror holder 1 is provided.
4 is fixed, and the mirror holder 14 holds the mirror 12. At this time, the mirror 12 is mounted such that its reflection surface 12a coincides with the center plane of the plate thickness of the biaxial spring 11.

The base plate 1 is provided on the lower end face of the frame 13.
5 is fixed. Further, a substrate 17 is fixed via an annular spacer 16. A drive mechanism 18 for rotating the mirror holder 14 is provided on the base plate 15. As the driving mechanism 18, an X-axis driving mechanism 18X that rotates around the X-axis, and the mirror holder 1
There are two Y-axis drive mechanisms 18Y for rotating the Y-axis 4 around the Y-axis, and two X-axis drive mechanisms 18X,
The Y-axis drive mechanisms 18Y are provided at intersections of the X-axis and the Y-axis, that is, at positions facing each other across the origin. However, in FIG. 3, one of the X-axis driving mechanism units 18X is not shown because it is on the near side in the drawing.

The Y-axis drive mechanism 18Y is a so-called moving magnet type voice coil motor, and mainly includes a bobbin 18Ya fixed to the base plate 15, a coil 18Yb wound on the bobbin 18Ya, and a mirror holder 1
A yoke 18Yc fixed to the fourth side, a magnet 18Yd fixed inside the yoke 18Yc, and a coil 18Y.
b. The heat sink 18Ye is provided between the heat conductive sheets (not shown). The bottom surface of the heat sink 18Ye is screwed to the base plate 15. The optical axis correction device 10 controls the rotation of the mirror holder 14 about the Y axis by controlling the driving of the two Y axis drive mechanisms 18Y.

Similarly, the X-axis drive mechanism 18X is also provided with the bobbin 1
8Xa, a coil 18Xb, a yoke 18Xc, and a magnet (not shown).
The rotation angle of the mirror holder 14 around the X axis is controlled. Similarly, the heat sink 18 is connected to the coil 18Xb.
Xe is installed.

On the base plate 15, an X-axis angle sensor 19X and a Y-axis angle sensor 19Y are fixed. In the optical axis correction device 10, based on the angle detection signals from the X axis angle sensor 19X and the Y axis angle sensor 19Y, the X axis driving mechanism 18X and the Y axis driving mechanism 18Y
And the angle of the reflection surface 12a of the mirror 12 is controlled. Thereby, the correction control of the optical axis is performed.

FIG. 1 is an enlarged view of the voice coil motor. (A) is a sectional view seen from the front, (b) is A in (a).
It is sectional drawing which followed the -A line. Here, although the Y-axis drive mechanism 18Y is shown, the X-axis drive mechanism 1
8X has a similar structure.

The heat sink 18Ye has a high thermal conductivity and is formed by bending a thin plate of oxygen-free copper or pure aluminum, which is a nonmagnetic metal, vertically upward and vertically downward. The upper portion is bent so that the vertical portion and a pair of tips cover three surfaces around the coil 18Yb. Coil 18Y
b. A resin heat conductive sheet 18Yf is applied to three surfaces around b.
From above, the heat conductive sheet 18Yf is fixed so as to be held above the heat sink 18Ye. The lower portion of the heat sink 18Ye is screwed to the base plate 15. With such a structure, the heat sink 18Ye
Heat generated by the coil 18Yb is applied to the heat conductive sheet 1
8Yf and radiated into the air, or from the heat sink 18Ye to the base plate 15 and radiated into the air.

FIG. 4 is an enlarged view of a portion B in FIG. In most cases, the copper wire 181Yb of the coil is wound so that the winding surface is not completely flat and is wavy as shown in FIG. In this state, the heat sink 18Y is a flat plate.
e, and even if the winding surface is ideally flat, the contact with the heat sink 18Ye is close to the line contact and the contact area is not large. Therefore, in the present invention, a heat conductive sheet 18Yf made of silicon resin having a higher heat conductivity than air is provided by using the copper wire 181Yb and the heat sink 18Y.
e, the copper wire 181Yb is held in contact with the heat conductive sheet 18Yf by the flexibility of the heat conductive sheet 18Yf, thereby increasing the contact area with the copper wire 181Yb.

In the above-mentioned heat sink, it is better to increase the contact area by using a silicon resin having a lower thermal conductivity than that of a metal, as compared with the case where the metal heat sink and the copper wire of the coil are in direct contact with each other. Typically, the amount of heat conduction increases. FIG. 5 shows the measurement result of the temperature rise of the coil.

In FIG. 5, a constant current was applied to the coil from the time when the temperature of the coil was 25 degrees, and the temperature rise of the coil was measured. In the measurement, when a current flows through the coil and the temperature of the coil rises, the resistance of the coil increases and the current decreases, so the current value is monitored with an ammeter so that the current value is always constant at 130 mA. The power supply voltage was adjusted. Further, such a rise in temperature is caused by a coil 51 without a heat sink, a coil 52 with an aluminum heat sink, a coil 53 with an aluminum heat sink and a silicon resin sheet,
The measurement was performed for each of 54 in the case of a coil provided with a heat sink made of oxygen-free copper and a sheet made of a silicone resin.

In FIG. 5, in the case of 52 and 53 provided with the same aluminum heat sink, the temperature rise is 28.8 degrees in the case of 52 using only the heat sink, but in the case of 53 using the resin sheet, 1 temperature rise
At 0.6 degrees, the temperature rise is suppressed to 1/3 as compared with the case of 52, and the effect of the resin sheet can be confirmed. This is probably because the heat transfer efficiency was improved due to the increase in the contact area of the resin sheet.

FIG. 5 also shows, as a reference, the measurement results of the case 54 using an oxygen-free copper heat sink.
The temperature rise in this case is 8.5 degrees, which is suppressed by about 20% as compared with 52 when using an aluminum heat sink, and by using an oxygen-free copper heat sink,
It can be seen that the temperature rise of the coil can be further suppressed.

As described above, by applying the resin sheet to the periphery of the coil and fixing the heat sink from above, the conductivity of the heat generated by the coil to the heat sink is increased, and the temperature rise of the coil is suppressed. Can be. Increasing the temperature of the coil causes an increase in the resistance of the coil, and accordingly the current flowing through the coil decreases. That is, by suppressing the temperature rise of the coil, the maximum current that can be passed through the coil increases, and the rotation angle of the mirror can be increased. Further, the rotation angle control of the mirror is stabilized, and the power consumption of the voice coil motor can be reduced.

By the way, as shown in FIG.
A method of bending the tip of the fin of the heat sink inward and improving the adhesion to the coil by the elastic force of the fin is extremely effective also in the present invention. In other words, when a resin sheet is applied around the coil and this heat sink is fixed from above, the resin sheet is strongly pressed against the coil by the elastic force of the fins, and easily contacts the coil whose surface shape is wavy. The resin can enter the narrow gap between the wire and the copper wire. For this reason, the contact area between the coil and the resin sheet can be increased.

When the heat sink having the narrow fins is attached to the coil from above the resin sheet,
Because the resin sheet covers the surface of the coil,
The tips of the fins do not directly contact the coil, and do not damage the coil and damage the insulating film of the copper wire. This is effective even when the width of the fin is equal to the width of the coil.

Further, by using a resin sheet, the amount of heat conduction from the coil to the heat sink is increased.
It is extremely important to increase the amount of heat radiation from the heat sink into the air and the amount of heat conduction from the heat sink to the base plate in order to suppress the temperature rise of the coil. For this purpose, it is effective to use the following method described in the conventional example in combination with the present invention.

That is, by extending the fin portion at the tip of the heat sink and enlarging the area of the fin, the amount of heat radiation from the heat sink to the air can be improved.
In addition, by increasing the area of the bottom of the heat sink, the contact area with the base plate is increased, and the amount of heat transfer from the heat sink to the base plate can be improved.

Next, a heat sink with further improved adhesion to the coil will be described. In FIG. 4, a gap, that is, an air layer still remains at the contact portion between the copper wire 181Yb of the coil and the heat conductive sheet 18Yf. This is because the sheet does not completely enter the narrow gap between the conductive wires because the heat conductive sheet 18Yf is in a sheet shape (solid). Further, in FIG. 1B showing the mounting structure of the heat conductive sheet 18Yf, a corner C of the heat sink is shown.
Has a gap between the heat conductive sheet 18Yf and the heat sink 18Ye. This gap can be eliminated by adjusting the heat sink to the winding shape of the coil. However, the winding shape of the coil varies, and it is difficult to manufacture a heat sink having a completely adhered shape.

FIG. 6 shows a heat sink that further improves the adhesion to the coil in order to solve such a problem. (A) is an attachment structure of a heat sink to a coil, (b) is an enlarged view of an E part of (a).

In the heat sink 18Yea shown in FIG. 6A, a gel (highly viscous liquid) is formed between the heat sink 18Yea and the coil 18Yb.
Is filled and cured. Since the heat conductive resin 18Yg is a silicone resin and is in a gel state, it enters the narrow gap between the copper wires 181Yb of the coil as shown in FIG. 6B, and can completely eliminate the air layer.
Therefore, the coil and the heat sink can be completely adhered.

As described above, the heat transfer from the coil to the heat sink can be further increased by bringing the heat sink and the coil into close contact with the gel resin, but the tip of the heat sink as described in the conventional example can be further improved. Extending the area of the fins to increase the amount of heat dissipated into the air, or increasing the area of the bottom of the heat sink to increase the contact area with the base plate and increase the heat transfer to the base plate It is very effective in enhancing the heat radiation performance of the device.

FIG. 7 shows a method of filling a silicon resin in such a heat sink. The coil 18Yb and the heat sink 18Yea in FIG.
It is sectional drawing along the FF line of (b).

First, the side surface of the coil 18Yb has a height equal to the height of the winding surface of the coil 18Yb and a width equal to that of the coil 18Yb.
The coil 18Yb is covered with the heat sink 18Yea from the opposite surface, and the tip of the fin of the heat sink 18Yea is brought into close contact with the plate 30.
Thereby, a space surrounded by the plate member 30, the heat sink 18Yea, and the coil 18Yb is formed. The nozzle 31 is inserted into this space from an injection hole 181Yea provided in a part of the heat sink 18Yea to inject the heat conductive resin 18Yg of silicon resin. The injected heat conductive resin 18Yg spreads over a narrow gap between the copper wires while extruding air, and finally the gap between the coil 18Yb and the heat sink 18Yea is filled with the heat conductive resin 18Yg, and this gap is filled. Almost 100% of the air layer disappears. When the injection of the heat conductive resin 18Yg is completed, the heat conductive resin 18Yg
To cure. Thereafter, by removing the plate member 30, the coil 18Yb, the heat conductive resin 18Yg, and the heat sink 1
A part in which three of 8Yea are brought into close contact and integrated is completed.

According to this method, the adhesion between the heat sink and the coil can be easily increased. For example, FIG.
In the case of using a heat conductive sheet and reducing the width of the tip of the fin of the heat sink to increase the adhesion by the elastic force of the fin as shown in FIGS. It wasn't enough to push it. However, in the method using the gel resin shown in FIG. 7, it is not necessary to rely on the elastic force of the coil, and it is possible to improve the quality by eliminating the unevenness of the close contact between the coil and the heat conductive resin. Further, since it is not necessary to narrow the tips of the fins of the heat sink, the copper wire of the coil is not greatly damaged when the heat sink is attached to the coil, and the reliability of the coil can be improved.

Further, the manufacturing method of FIG. 7 has an advantage that the assembling work is simpler and that it is easy to cope with the automation of the manufacturing process, as compared with the method of assembling by sandwiching the resin sheet between the coil and the heat sink.

That is, the assembling process of FIG. 1 is a process of applying a sheet of silicon resin produced according to the dimensions of the coil to the coil so as not to be displaced, and further attaching a heat sink from above. During this process, the resin sheet may shift and protrude from the heat sink, so that an assembling technique for preventing this is required. However, in the manufacturing method shown in FIG. 7, a coil, a heat sink, and a plate material for enclosing the gel-like silicon resin are positioned and fixed, and the gel-like silicon resin is injected, filled, and hardened. And not.

[0064]

As described above, in the first optical axis correction device of the present invention, since the heat conductive sheet is provided between the coil of the voice coil motor and the heat sink, the heat conductivity from the coil to the heat sink increases. The heat radiation performance of the voice coil motor is improved. Thereby, the rotation drive control of the mirror is stabilized, and the power consumption of the voice coil motor can be reduced. Also, when attaching a heat sink to the coil,
Since the heat sink is fixed on the heat conductive sheet, the copper wire of the coil is not damaged, and the quality and reliability of the coil are improved.

Further, in the second optical axis correcting device of the present invention, the gap between the coil of the voice coil motor and the heat sink is injected and filled with a gel-like heat conductive resin, and is cured. The thermal conductivity is further increased, and the heat radiation performance of the voice coil motor is further improved. As a result, the rotational drive control of the mirror can be stabilized, and the power consumption of the voice coil motor can be reduced.

Further, in the method of manufacturing a voice coil motor according to the present invention, a gel-like heat conductive resin is injected into a space surrounded by the plate material, the heat sink, and the coil through an injection hole provided in a part of the heat sink, thereby forming the coil. Since the heat conductive resin is filled and cured in the gap between the heat sinks, a voice coil motor having high heat radiation performance and improved quality can be easily manufactured, and it is easy to respond to automation of the manufacturing process.

[Brief description of the drawings]

FIG. 1 shows an enlarged view of a voice coil motor of the present invention,
(A) is a cross-sectional view seen from the front, (b) is AA of (a).
It is a sectional view along a line

FIG. 2 is a plan view showing an optical axis correction device of the present invention.

FIG. 3 is a sectional view taken along line DD of FIG. 2;

FIG. 4 is an enlarged view of a portion B in FIG.

FIG. 5 is a graph showing measurement results of a temperature rise of a coil.

FIGS. 6A and 6B are views showing a heat sink with further improved adhesion to the coil, wherein FIG. 6A is a mounting structure of the heat sink to the coil, and FIG. 6B is an enlarged view of a portion E in FIG.

FIG. 7 is a view showing a method of filling a silicon resin in the heat sink of FIG. 6 (a).

FIG. 8 is a diagram showing a schematic configuration of an optical system portion of a conventional optical space transmission device.

FIG. 9 is a plan view showing a conventional optical axis correction device.

FIG. 10 is a sectional view taken along line GG of FIG. 9;

FIG. 11 is a cross-sectional view showing attachment of a conventional heat sink to a coil.

FIGS. 12A and 12B are diagrams showing a first example of a heat sink having improved adhesion to a coil, wherein FIG. 12A shows a structure of a conventional heat sink, and FIG. 12B shows a structure of a heat sink having improved adhesion.

FIGS. 13A and 13B are diagrams showing a second example of a heat sink having improved adhesion to a coil, wherein FIG.
(B) shows the mounting structure of the heat sink of (a) to the coil.

FIG. 14 is an enlarged view showing a contact portion between a copper wire of a coil and a heat sink, and FIG.
(B) shows the case of a coil having winding disturbance.

[Explanation of symbols]

18Ya ... bobbin, 18Yb ... coil, 18Ye ...
... heat sink, 18Yf ... thermal conductive sheet, 18Yg
... thermal conductive resin, 30 ... plate material, 181Yb ... copper wire

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 15/12 33/16 F term (Reference) 2F065 AA19 AA32 AA37 CC09 DD16 FF43 FF65 GG04 HH03 JJ05 JJ16 JJ18 LL13 LL46 TT02 5H609 BB06 PP09 QQ23 RR63 RR74 RR75 5H615 AA01 BB01 BB04 PP01 PP12 RR02 SS44 TT26 5H633 BB08 GG02 GG04 GG05 GG09 GG11 GG12 GG23 HH03 HH05 HH22 HH25 JB01 JB03 AB05 5B002

Claims (3)

[Claims] 1. An optical axis correction device for correcting an optical axis in an optical space transmission device, comprising: a mirror that reflects a laser beam; a mirror holding member that holds the mirror; A support member rotatably supporting about a first axis and a second axis on a plane parallel to the reflection surface of the mirror; and independently of the mirror about the first axis and the second axis. A magnet provided on the mirror holding member side for rotating, a coil for driving the magnet, a heat conductive sheet covering three surfaces around the coil, and a coil connected via the heat conductive sheet. , A rotation mechanism portion having a heat sink that is covered in a U-shape, and the other surface is in close contact with the base surface; a rotation angle detection mechanism portion that detects a rotation angle of each of the mirrors about each of the axes; First axis And a rotation control means for controlling the rotation mechanism so that the rotation angle about the second axis becomes a desired angle. 2. An optical axis correction device for correcting an optical axis in an optical space transmission device, comprising: a mirror for reflecting a laser beam; a mirror holding member for holding the mirror; A support member rotatably supporting about a first axis and a second axis on a plane parallel to the reflection surface of the mirror; and independently of the mirror about the first axis and the second axis. For rotating, a magnet provided on the mirror holding member side, a coil for driving the magnet, a heat sink that covers the coil in a U-shape, and the other surface is in close contact with the base surface, and the coil A rotation mechanism portion that is filled in a gap with the heat sink and has a heat conductive resin that increases thermal conductivity from the coil to the heat sink; and detects a rotation angle of the mirror around each axis. A moving angle detection mechanism; and a rotation controller configured to control the rotation mechanism so that the rotation angles of the mirror around the first axis and the second axis are each a desired angle. An optical axis correction device, comprising: 3. A heat sink installed close to three peripheral surfaces of the coil for dissipating heat generated from the coil;
In the method of manufacturing a voice coil motor having a heat conductive resin filled in a gap between the heat sink and the coil, the side surface of the coil is brought into close contact with a plate material, and the heat sink is brought into close contact with an end portion of the coil. Arranged around the coil, injecting a gel-like heat conductive resin from a hole provided in a part of the heat sink, filling the gap between the plate material, the coil and the heat sink with the heat conductive resin,
A method for manufacturing a voice coil motor, wherein the heat conductive resin is cured and the plate material is removed.