JPH05298727A - Galvanomirror drive - Google Patents

Abstract

PURPOSE:To improve the deviation of the axis of rotation and the assembling accuracy of a spring itself by a galvanomirror using a cross spring-supported system. CONSTITUTION:A cross spring 36 is an integral type to hold the relative location of respective plate springs. Also, when one side is supported by a cantilever pin and the other is supported by a cross spring, the axis of rotation of a galvanomirror is determined by the position of the supporting pin. Therefore, the title apparatus is provided with a vertical fine adjustment mechanism 38 for aligning the position of a cross-point being the center of rotation of the cross spring with the axis of rotation of the supporting pin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light spot positioning mechanism for an optical disk, and more particularly to a galvanometer mirror driving device provided in a fixed optical system of a separation optical system type.

[0002]

2. Description of the Related Art Conventional optical disk devices of the separation optical system include a plurality of systems, but the system in which only the objective lens and the focusing mechanism are mounted on the access mechanism is the lightest. As an example of this type of device,
Proceedings of 990 IEICE Spring National Convention 4-
The optical disk device described on page 474 can be mentioned. In this device, a fixed optical system is equipped with a galvano mirror, and the rough positioning of the light spot in the radial direction of the disk is performed by moving the objective lens on the access mechanism and rotating the galvano mirror by a minute high-frequency amplitude. The light spot is positioned with high precision.

For such a barbano mirror, the Japan Society of Mechanical Engineers, Vol. 57, No. 534 (1991-2), No. 90-
The one using the cross spring support method shown in 0772A is general. However, in the case of the cross spring support method, since multiple leaf springs are used, if deviation of the movable part in the direction of the rotation axis occurs in each leaf spring during assembly, the rigidity of the cross spring itself around the rotation axis will increase. , The primary resonance frequency is high,
The response of the galvanometer mirror becomes low.

[0004]

In the cross spring supporting type galvanometer mirror driving device, a plurality of leaf springs must be assembled without particularly tilting in the direction perpendicular to the rotation axis of the movable part. When the leaf springs are tilted in the above-mentioned directions during assembly, the bending rigidity of the cross spring becomes higher than the designed value, and the high responsiveness required for the galvano mirror cannot be realized.

An object of the present invention is to provide a galvano mirror driving device which can realize a high responsiveness as a galvano mirror by suppressing positional displacement and inclination during assembly as much as possible.

[0006]

In order to achieve the above object, the present invention provides a pin supporting one side of a rotary shaft of a movable part,
In the galvano-mirror drive device in which the other side is configured to support a cross spring, a plurality of leaf springs forming the cross spring are integrated and supported by the integrated cross spring. Also,
The movable-part-side mounting position and the fixed-base-side mounting position of the cross spring are arranged at positions equidistant from the intersection of the leaf springs.
A protrusion as a mark is provided on the side of the movable portion on the side where the cross spring is supported, which serves as a center of rotation, and a vertical spring fine adjustment mechanism is provided on the cross spring fixed base.

[0007]

According to the present invention, in the cross spring support system of the galvano mirror driving device, the leaf springs of a plurality of plates are integrated so that the relative positional relationship of the leaf springs can be maintained.
That is, it is possible to suppress the displacement of the spring, which occurs when the spring is tightened, particularly, the displacement in the direction perpendicular to the rotation axis of the movable portion. Also, by providing a vertical fine movement mechanism on the cross spring mount, the rotation center on the pin support side and the rotation center on the cross spring side can be aligned with the rotation axis of the movable part, and external force due to axis deviation can be suppressed as much as possible. You can

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, a movable head 8 is provided so as to face a disk 7 which is rotated at a constant speed by a spindle motor (not shown) and whose data is recorded as a spiral track on its recording surface. There is. Movable head 8
The objective lens 9 is supported by the metal spring 10 on the uppermost part of the body 44 of FIG. The rigidity of the metal spring 10 in the disk normal direction is low, and the rigidity in the other directions is large so that vibration does not adversely affect positioning control and data writing and reading. Inside the body 44, the start-up mirror 1
1 is fixed, and the outgoing light flux incident from the fixed optical system 18 is reflected and guided to the objective lens 9. Furthermore, body 4
A head drive coil (head drive means) 14 is attached to each of the left and right sides of the disk 4, and the movable head 8 can be moved in the radial direction of the disk 7 together with a magnetic circuit (not shown). Further, five ball bearings are attached to the body 44 via fixed shafts, and four of them are in contact with the outer ring of the main guide shaft 13 to move the movable head 8 toward the center of the disk 7. It has the role of leading with high precision and low friction. The remaining one ball bearing is in contact with the sub guide shaft 13 to restrain the rotation of the movable head 8 around the main guide shaft 13. Further, the sixth ball bearing 16 is attached to the spring 17, and is pressed against the sub guide shaft 13 by the preload of the spring 17.

In the fixed optical system 18, the laser 20, the photodetectors 27, 28, 31 and each optical system component are fixed on the base 19. Hereinafter, the configuration and main operation of the optical system will be described while following the light emitted from the laser (laser light source) 20.

The incident light flux emitted from the semiconductor laser 20 is collimated by the collimator lens 21 and passes through the prisms 22 and 23 to widen the width in the direction parallel to the base 19. The incident light flux emitted from the semiconductor laser 20 is the base 1
Although it has an elliptical cross section in which the width in the direction perpendicular to 9 is larger than that in the parallel direction, it becomes a circular cross section by passing through the prisms 22 and 23. The incident light beam then passes through the compound prism 24.
Of the galvano mirror 1 through the half mirror portion of the galvano mirror 1, and is reflected at a right angle by the mirror 4 of the galvano mirror 1, and further reflected by the fixed mirror 5 and the fixed mirror 6.
Is reflected by and goes toward the rising mirror 11 of the movable head.

The emitted light beam is reflected by the rising mirror 11 on the movable head 8 and is narrowed down by the objective lens 9 to form a minute light spot having a diameter of about 1.6 μm on the recording surface of the disk 7 and reflected there. Then, it again passes through the objective lens 9 and becomes parallel light. And again the launch mirror 11
Is reflected by the half mirror of the compound prism 24 after passing through the galvanometer mirror 3, the fixed mirrors 6, 5 and the mirror 4, and the light in the direction of the Wollaston prism 29 is provided by the half mirror provided in the center of the compound prism 24. Then, it is divided into light that further travels in the composite prism 24. The light is separated into two rays, an ordinary ray and an extraordinary ray, by the Wollaston prism 29, and while converging by a lens attached to the end face of the Wollaston prism, the direction is changed by the reflection mirror 30 toward the signal detector 31, The spots of the ordinary ray and the extraordinary ray are connected on the photodetector divided into two on the signal detector 31. The signal detection circuit detects the data recorded on the recording surface of the disk 7 as a magneto-optical signal whose magnetization direction is upward or downward by obtaining the difference between the detection signals of the ordinary ray and the extraordinary ray.

On the other hand, the light traveling through the compound prism 24 is reflected by the total reflection portion provided at the end of the compound prism 24, enters the lens 25, and is converged by the lens 25. The converged light is separated into reflected light and passing light by the half prism 26, the reflected light enters a servo signal detector 27 provided in front of the focus of the converged light, and the passed light is provided behind the focus of the converged light. It is incident on the servo signal detector 28.

The data on the recording surface of the disk 7 has a fixed optical system 8 in which a deviation (track deviation) from a guide groove having a depth of about 0.1 μm and a width of about 0.5 μm and a focus deviation of a light spot are fixed.
The objective lens 9 is driven in the normal direction of the disk 7 by a focusing actuator (objective lens driving means) (not shown), which is detected by the servo signal detectors 27 and 28. In addition, the galvanometer mirror 1 that reduces the track deviation is driven as described later. The light spot is displaced at a low frequency and a large amplitude in the guide groove on the disk 7 by the head drive coil.
Is followed by moving, and the displacement of small vibration at the remaining high frequency is followed by rotating the galvanometer mirror 1. Tracking by moving the movable head 8 and galvanometer mirror 1
The distribution of tracking by is determined by the track following circuit.

In the servo signal detectors 27 and 28, a vertical strip-shaped track direction detecting portion is provided at the center of the detector, and the track deviation detecting portion is vertically divided into two parts. The imbalance of the light spot diffracted light is detected and fed back as a track deviation signal.
On the other hand, regarding the defocus, there are defocus detection units on the left and right of the track displacement detection unit, and the defocus is detected as the output difference of the defocus detection units of the servo signal detectors 27 and 28. Following the above description of the entire apparatus, the galvano mirror 1 of the present invention will be described.

2 and 3 are perspective views of the galvanometer mirror. As described above, the barvano mirror controls the tracking direction by rotating the mirror, and supports the holder 2 at both ends in the rotational direction of the galvano mirror. The galvanomirror of the present invention has a pin support system on one side and a cross spring support system on the other side.
FIG. 2 is a perspective view seen from the pin support side,
FIG. 3 is a perspective view seen from the cross spring support side. Two mirrors 3, 4 and a galvanometer mirror driving coil 32 are attached to the holder 2, and are driven to rotate by supplying a current to the driving coil 32 by a magnetic circuit (not shown).
The light flux is moved in the track direction of the disk 7 by the mirrors 3 and 4. Support pin 33 is attached to the rotation axis of the galvanometer mirror.
Is arranged on the rotating shaft and rotates with low friction through a sleeve (not shown) fixed to the base 19. The other support portion is configured to be supported by the cross spring 34 formed of two leaf springs. The end portion of each leaf spring is a spring mount 3 fixed to the holder 2 portion of the galvanometer mirror and the base 19.
It is attached to No. 5, and the intersection of two leaf springs is made to correspond on a rotating shaft. That is, the position of the support pin 33 and the intersection of the cross spring 34 are arranged on the rotation axis of the galvanometer mirror.

FIG. 4 is a perspective view of an integral type cross spring support portion which is an embodiment of the present invention. Further, for the purpose of explaining the integrated type cross spring, FIG. 5 is a perspective view of a cross spring support portion composed of two conventional leaf springs.

The cross spring 34 is attached by a screw to a spring mount 35 which is usually fixed on the base 19. Therefore, when tightening the screw, a force also acts on the spring itself in the rotation direction of the screw, and the spring moves around the screw mounting position in the direction of the arrow shown in the figure. 2 shown in FIG.
When one leaf spring is used, the above-mentioned force acts on each leaf spring and the two leaf springs are displaced in opposite directions. As a result, when the galvanometer mirror rotates, each leaf spring of the cross spring 34 moves obliquely with respect to the plate thickness direction, so that the rotational rigidity of the cross spring is increased and the response of the galvanometer mirror is extremely lowered. Therefore, an integrated cross spring 36 shown in FIG. 4 was proposed. Since the cross spring 36 is formed by integrating two conventional leaf springs, the relative positional relationship between the two leaf springs can be maintained. Although not shown in the figure, a plurality of leaf springs may be used. Further, with respect to the force in the rotation direction generated when tightening the screw, the spring mounting base 35 is provided with four rotation preventing pins 43, and the displacement position of the spring is suppressed by these pins.

FIG. 6 is a plan view of a spring which is an example of an integral cross spring. An etching method is used for manufacturing, and the plane cross spring 36 is actually bent and used.
FIG. 7 shows a state in which the cross spring 36 is attached to the holder 2 and the spring mount 35. Here, as shown in FIG. 7, the distance A ″ between the spring mounting positions in the holder 2 and the spring mounting base 3 are
The relationship of the distance A'between the spring mounting positions in No. 5 is set to A '= A ".

This is because the intersection of the cross spring 36 is aligned with the rotation axis of the galvanometer mirror, and the cross spring 36 is rotated about the intersection. This can be achieved more easily than the above-mentioned relationship between the mounting distances. In Figure 6,
The specific mounting positions of the holder 2 portion of the cross spring 36 and the spring mounting base 35 at that time are shown. That is, the leaf springs are arranged at equal intervals from the intersection.

FIG. 8 is a conventional view and FIG. 9 is a development view of the holder 2 portion of the galvanometer mirror of the present invention. Conventionally, the pin 2 on the pin support side of the holder 2 has a hole formed at the center of the rotary shaft and the support pin 33 is press-fitted therein, but nothing has been done on the cross spring support side. Therefore, matching the intersections of the cross springs on the rotation axis depends on the manufacturing precision and the assembly precision of the mechanical parts. In one embodiment of the present invention, a hole at the center of the rotation axis is penetrated, and as a mark at the center of the rotation axis on the cross spring support side, for example, a pointed pin is inserted into the hole as shown in the holder 2 The protrusion 37 is provided on the side surface of the cross spring supporting side. After that, it was decided to press-fit the support pin 33. At this time, in order to maintain the rigidity of the holder 2, the length of the pin is determined so as to reduce the space inside the hole of the holder 2.

FIG. 10 shows an up-and-down fine movement mechanism for aligning the intersection of the cross spring with the rotating shaft, which is an embodiment of the present invention. In the case of the pin support system on one side and the cross spring support system on the other side, the rotary shaft is almost determined by the position of the support pin. This is for positioning at the intersection of the cross spring,
This is because the positioning rigidity of the support pin is high. for that reason,
As described above for assembling the galvanometer mirror, it is important to match the intersections of the support pin and the cross spring, and the displacement of the rotation axis at each support portion greatly affects the performance of the galvanometer mirror.

Therefore, the galvanometer mirror is provided with a mechanism for adjusting the above-mentioned rotation axis deviation. The spring mount 35 fixed to the fixed optical system base 19 has a compression coil spring 41.
Also, it is configured to be attached to the base 19 by the fixing screw 42 via the adjustment block 39. When the rotation center of the support pin and the intersection of the cross spring 36 are displaced in the vertical direction, the adjustment blocks 39 provided on the left and right are moved by the adjustment block fine adjustment screws 40 to adjust the spring mount 35 itself. With this mechanism, the rotation axis can be easily adjusted.

According to the present embodiment, in the galvano mirror in which one side is supported by pins and the other side is supported by a cross spring, it is possible to eliminate the positional deviation at the time of mounting the cross spring, and further to align the rotation axis of the support pin and the cross spring. Can be done easily. As a result, high responsiveness of the galvano mirror itself is possible, and the track following accuracy can be significantly improved.

[0024]

According to the galvano-mirror driving device of the present invention, the relative positional relationship between the two leaf springs forming the cross spring can be maintained, and further, the cross spring can be mounted on the rotary shaft of the galvano mirror. It became easier to match the center of rotation. Therefore, a high response of the galvanometer mirror is possible, and the tracking accuracy of the track can be improved.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a main part of FIG.

FIG. 3 is a perspective view showing a main part of FIG.

FIG. 4 is an explanatory view of the operation of the present invention.

FIG. 5 is an explanatory view of a conventional operation.

FIG. 6 is a plan view of an embodiment of the present invention.

FIG. 7 is a plan view of the second embodiment of the present invention.

FIG. 8 is a plan view of the third embodiment of the present invention.

FIG. 9 is a plan view of the fourth embodiment of the present invention.

FIG. 10 is a plan view of the fifth embodiment of the present invention.

[Explanation of symbols]

2 ... Holder, 33 ... Support pin, 34 ... Cross spring, 35 ...
Spring mount, 36 ... Integrated cross spring, 38 ... Fine adjustment mechanism, 39 ... Adjustment block, 40 ... Adjustment block fine adjustment screw.

Claims (1)

[Claims] 1. A galvano-mirror drive device having one side supported by a pin and the other side supported by a cross spring with respect to a rotary shaft of a movable part, wherein a plurality of leaf springs forming the cross spring are integrated. A galvanometer mirror drive device, which is supported by an integral cross spring.