JPS5843063Y2 - Movable mirror device in optical information recording medium disc playback device - Google Patents

Description

[Detailed explanation of the invention] An optical information recording medium disc (
An optical system that projects a tiny diameter light beam (hereinafter sometimes abbreviated as "disc") onto the disc for reading information, and uses the reflected light or transmitted light to read and reproduce the information in the recording trace of the disc. A playback device for a digital information recording medium disc can read information from the recording trace of the disc without contacting the disc. This type of disc has the advantage that it is easy to set the playback mode to any one of still image playback mode, quick motion playback mode, slow motion playback mode, normal playback mode, etc. Also due to the unavoidable disc wobbling in playback equipment.

In order to always project a spot of light with a predetermined minute diameter onto the board surface, automatic focusing control is required. Automatic tracking control of the record trail is required in order to trace the record.

In addition, disks are designed to be rotated accurately at a predetermined number of rotations when reproducing information signals, but disks are inevitably subject to mechanical deformation due to various other reasons during manufacture. Therefore, even if it is rotated at a constant number of revolutions during playback, the presence of the mechanical deformation described above causes a change in the relative speed between the recording trace and the playback needle, which causes a change in the playback signal. contains so-called time axis error (jitter), so conventionally the time axis error correction signal obtained by comparing the reference signal in the reproduced signal with the standard signal is used to correct the time axis error. The signal is applied to a drive device of a control circuit (jitter correction control circuit), which in turn drives the reproducing element in the direction of extension of the recording trace to prevent a time axis error from occurring in the reproduced signal.

Conventionally, in a playback device for an optical information recording medium disc, as shown in FIG. The rotating mirrors MJ and Mt are peeled off with the mirror Mt interposed therebetween.

By controlling each one individually using a jitter correction control signal and a tracking control signal.

Arrow J1 in the diagram of one rotating mirror MJk for jitter correction control
(spora of light)k on the surface of the disk D in the direction of extension of the recording trace (direction of arrow J2 in the figure), and move the other rotating mirror Mt for tracking control in the direction of the arrow J2 in the figure. is rotated in the direction of arrow t1 and moved in a direction perpendicular to the recording trace on the surface of the optical sporatra disk D (direction of arrow t2 in the figure) to perform jitter correction and tracking control, and further, The objective lens CI was moved in the direction of arrow f in the figure by a focus control drive mechanism (not shown) to which a focus control signal is applied, thereby performing focus control.

As mentioned above, in the conventional optical information recording medium disc playback device, jitter correction control, tracking control,
Separate control devices were used for control and focus control, making the optical system complex and difficult to assemble and adjust.
In addition to the unavoidable expensiveness of the equipment, a certain distance between the objective lens and the rotating mirrors MJ and ML is unavoidable. If the moving angle is large, part or all of the light beam incident on the objective lens O may protrude beyond the objective lens O, which limits the range of jitter correction and tracking control, and also There is a drawback that the utilization rate is not sufficient, and due to the structure of the rotary mirror, bunching occurs in the high range, making it difficult to perform accurate control.

In order to solve the above-mentioned conventional problems, the applicant company first uses a jitter correction control signal, a tracking control signal, etc. in the optical path between the light source and the optical information recording medium disk. In an optical information recording medium disk reproducing apparatus that is provided with a movable mirror that can be driven to compensate for jitter and for tracking, the normal to the surface of the movable mirror is 1 within 2,000 planes that include the mirror plane Φ arrow and are orthogonal to each other.
A movable mirror is elastically supported so that it can be swung around each fulcrum, and a plane perpendicular to the normal to the surface of the movable mirror is divided into four parts. A coil device comprising at least four coils each arranged at a movable mirror and a current in a predetermined direction flowing through each coil in the coil device. Good results have been achieved by providing a movable mirror device for an optical information recording medium disk reproducing device, which is equipped with a DC magnetic field generating device capable of generating electromagnetic force in a predetermined direction to each coil in the device. However, since this previously proposed movable mirror device was driven by a movable coil, it had the advantage of excellent dynamic characteristics from a theoretical perspective, but on the other hand, the method of drawing out the current supply line to the movable coil was difficult. If it is inappropriate, it may cause malfunction or accidents such as the supply line being cut, resulting in low reliability during use and problems in terms of productivity. .

The present invention provides a movable mirror device in which the coil device is of a fixed coil type, and the problems of the above-mentioned previously proposed devices can be satisfactorily resolved. The contents will be explained in detail with reference to the accompanying drawings.

FIGS. 2 to 5 of the accompanying drawings are a longitudinal sectional side view (view a in each figure) and an exploded perspective view (view b in each figure) of each embodiment of the movable mirror device of the present invention, In each figure, reference numeral 1 designates a reflecting mirror (hereinafter referred to as mirror 1), 2U is a flexible wire having a thick portion 2a at one end, and the wire 2 is, for example, heated and melted at the tip. Nylon wire with a bead formed thereon, or stainless steel wire with a knot tied at the end, etc. may also be used.

Reference numeral 3 denotes a mirror mounting body having a hole 3a through which the wire 2 described above can pass through, and a recess 3b for receiving the thick end portion 2a of the wire 2. 1, and may be configured as a disc-shaped member made of a non-magnetic material, for example, aluminum.

4 is a permanent magnet, and this permanent magnet 4 (when a plurality of permanent magnets are used as in the embodiment shown in FIGS. 4 and 5, subscripts a, b, c, etc. are added to the number 4) ), one end of the permanent magnet 4 is fixed to the mirror mounting body 3, and the permanent magnet 4 has one end fixed to the mirror mounting body 3 with a magnetic pole of one polarity. and mirror 1 so that the other end becomes the magnetic pole of the other polarity.
It is magnetized so that the magnetic poles are aligned in the direction of the normal to the surface.

5 is a damper made of a viscoelastic material such as rubber, and 6 is at least four coils, and the coils 6 serving as containers are given subscripts a, l), etc., respectively. are distinguished from each other.

γ is a fixing member for fixing the damper 5, coil 6, etc. described above, and this fixing member 7 has a hole 7a□ through which the wire 2 described above is passed, and a screw into which a set screw 8 for clamping the wire 2 is screwed. hole 7b.

In the buttons shown in FIGS. 2 and 3, 7a is a pole, and in the button of the embodiment shown in FIG. 3, a clamp member 9 is used for clamping the wire 2.

The fixing member 7 described above is made of a non-magnetic material such as aluminum.

In the embodiment shown in FIGS. 2 and 3, the permanent magnet 4 fixed to the mirror mounting body 3 is a single ring-shaped permanent magnet, and in the embodiment shown in FIGS. 4 and 5, The permanent magnets 4 fixed to the mirror mounting body 3 are four cylindrical permanent magnets 48 to 4d.

1. First, the movable mirror device shown in the embodiment shown in the second figure has one end of each of the four coils 6a to 6d mounted on the coil mounting surface 7c of the fixed member 7 made of a non-magnetic material, and Place the center part of the mirror mount 3 on the tip via the damper 5, and open the center hole 5a of the damper 5 and the hole 7 of the pole 7a.
It is assembled by pulling the wire 2 inserted through a1 so that a suitable tension is applied to the wire 2, and then fixing the wire 2 with a set screw 8.

In the above assembly, the mirror 1 and the permanent magnet 4 are not necessarily fixed to the mirror mounting body 3 in advance.

In the embodiment shown in the second figure, the swinging fulcrum of the movable part is located on the wire 2 in the damper 5, and the wire 2 compresses the damper 5 with an appropriate tension, so that the movement of the swinging fulcrum that occurs during operation is prevented. Not a problem.

In this way, the components shown in FIG.
In the movable mirror device shown in the second figure assembled as shown in the figure, one end surface of the permanent magnet 4 is spaced apart from the free ends of the four coils 6a to 6d fixed to the fixed member 7 with a certain gap. They are said to be facing each other.

The size of the gap length that should be provided between the free ends of the coils 6a to 6b and one end surface of the permanent magnet 4 is such that even when the movable mirror 1 swings about the swing fulcrum according to the control operation, The size is such that the surface of the permanent magnet 4 and the coils 6a to 6d do not come into contact with each other.

Further, the movable mirror device shown in the embodiment shown in the third figure has a ring-shaped damper 5 fixed to the peripheral part of the fixed member 7,
The damper 5 receives a ring-shaped permanent magnet fixed to the mirror mounting body 3, and is inserted through the center hole 5a of the damper 5, the hole 7a1 of the pole 7a, the hole 93 of the wire clamp member 9, etc. The wire 2 is assembled by pulling the wire 2 so that a suitable tension is applied to the wire 2, and then fixing the wire 2 with a set screw 8.

In the movable mirror device of the embodiment shown in the third figure, the second
Since a larger ring damper is used compared to the damper used in the embodiment shown in the figure, the damping characteristics against the swinging motion of the movable part are improved compared to the movable mirror device of the embodiment shown in the second figure. It becomes what it is.

The movable mirror device shown in the embodiment shown in FIG. 4 and FIG.
It is assembled so that the tips of the permanent magnets 4a to 4d described above are inserted into the inside of the magnet.

The diameters of the cylindrical permanent magnets 4a to 4d are made smaller than those of the coils 6a to 6d so that the permanent magnets do not come into contact with the inner surface of the coils even when the movable part performs a rocking motion. Ru.

In the embodiment shown in FIGS. 4 and 5, the force generated by the permanent magnets 4a to 4d and the coils 6a to 6d is greater than the force generated by the permanent magnets when the coil length and the length of the permanent magnet are equal. However, the length of 1/2 of that length is at its maximum when it is inserted into the coil, and in this state the movable part can be driven with the highest efficiency.

Furthermore, in the movable mirror device of the embodiment shown in FIG. 4, the outermost peripheral portion of the movable part is supported by the ring-shaped rubber damper 5, so that the movable part can be well damped against rocking motion. In addition, since the damper 5 can seal the part of the movable mirror device where the permanent magnet is present, there is also the advantage that iron powder etc. will not be attracted to the permanent magnet. .

The movable mirror device shown in the embodiment shown in FIG.
b', and a membrane-like member whose inner end 5c is fitted into a groove 3b provided on the outer periphery of the mirror mount 3 is used.

Therefore, in the movable mirror device of the embodiment shown in FIG. 5, the damper 5 made of rubber in the movable mirror device of the embodiments shown in FIGS. Unlike the cam damper 5, which is compressed and deformed during motion, the stiffness of the membrane damper 5 can be appropriately selected as the cam damper 5, which is displaced during the rocking motion of the movable part. It is also possible to prevent lateral displacement of the movable part during exercise.

Further, in the movable mirror device shown in the embodiment shown in the fifth figure, in addition to the four coils 68 to 6d used as the fixed coil 6 in the embodiments shown in the second to fourth figures, the four coils 68 to 6d described above are used. A coil 6e having a large diameter is provided to surround the coils 6a to 6d'.

6 to 9 are diagrams showing the operating principle and drive mode examples of the movable mirror device of the present invention, and in each of these diagrams, one-wave tracking control currents such as +T and -T, and +J, -J, etc. are currents for jitter correction, and signs such as +, - indicate the polarity of the current.Furthermore, T and J shown with buttons and arrows in the figure indicate the rotational force direction of the movable part. This shows that.

In the example shown in Figure 6, the permanent magnet 4 is shown as being magnetized so that its lower surface becomes the north pole, and the coil 6a to which a current of 10 T is supplied is 6
The N pole appears on the upper end side of a.

On the other hand, the coil 6c to which a current of -D is supplied has an S pole at its upper end, and the coil 6d to which a current of +J is supplied has an N pole at its upper end, and the other -
The coil 6b to which the current of J is supplied has an S pole on the upper end side of the coil 6b.

Therefore, in this state, the movable part of the movable mirror device is
Tracking control currents +T and -T are coils 6a and 6c.
The jitter correction current +J is supplied to the jitter correction current +
, -J is the coil 6d.

6b, it is rotated about the pivot point in the direction of arrow J in the figure.

If the direction of the current supplied to each coil 63 to 6d is opposite to that shown in the figure, or if the polarity of the permanent magnet 4 is opposite to that shown in the figure, the rotation of the movable part will be Of course, the direction is opposite to that shown.

The magnitude of the rotation angle described above is such that the torque generated by the magnetic attraction 1 repulsion between the magnetic pole of the permanent magnet 4 and the magnetic pole generated in the coil by the current flowing through each coil is balanced by the reaction force of the damper 5. It's an angle.

Therefore, this movable mirror device can independently perform tracking control operation and jitter correction operation by flowing a tracking control current and a jitter correction current to each specific fixed coil of the movable mirror device. By disposing this movable mirror device in the optical path between the light source and the optical information recording medium disc, tracking control and jitter correction can be performed by two-dimensional movement of one movable mirror. be.

FIG. 7 shows, like the movable mirror device of the embodiment shown in FIG.
The four coils 68 to 6d and the four coils 6a described above.
This shows an example of a driving mode when one coil 6e surrounding the coil 6d is used, and in this FIG. 7, a current of +J is supplied to the coil 6a and the coil 6C, and the coil A current of -J is supplied to the coil 6b and the coil 6d,
Furthermore, a current of 10 T is supplied to the coil 6e,
A case is shown in which the movable mirror device is rotated in the directions of arrow T and arrow J in the figure.

In this figure, the magnetic poles of the permanent magnets 48 to 4d are shown as the magnetic poles at the ends of the permanent magnets inserted into the coils 6a to 6d.

FIG. 8 shows an arithmetic circuit 10a for supplying current to each coil 6a to 6d in the embodiment shown in FIGS. 2 and 3.
This shows an example of a case where the magnetic flux is transmitted through 10 dk, and when this example is used, the efficiency of using the magnetic flux of the permanent magnet is twice that of the case shown in FIG.

Fig. 9 shows the coils 6a to 6dffi each having a double winding, and by doing as shown in Fig. 9, the utilization efficiency of the magnetic flux of the permanent magnet can be improved without using the arithmetic circuits 10a to 10de. can be done.

Since each coil is a fixed coil, even if the coil is a double coil as shown in FIG. 9, it has nothing to do with the weight of the movable part.

In implementing the movable mirror device of the present invention, it goes without saying that the arrangement of the coils, the wiring method, the shapes of the dampers and permanent magnets, etc. may be changed in various ways.

In the movable mirror device of the present invention, the previously proposed patent application No. 52-953
Similar to the movable mirror device No. 48, it not only solves the various drawbacks of the conventional device, but also solves the problems of the previously proposed device mentioned above, namely, the current supply line to the moving coil. The movable mirror device 1/l of the present invention has disadvantages such as deterioration of operating characteristics or disconnection.
This problem is automatically solved by using a fixed coil type coil, and since the coil is a fixed coil type in the movable mirror device of the present invention, the number of turns of the coil winding can be reduced. The operating characteristics of the vibration system will not deteriorate even if the weight of the coil increases by increasing the number of coils sufficiently or by increasing the diameter of the wire used for one winding. There are also advantages such as the ability to easily configure the coil so that it will not burn out even when a large current is passed through it.According to the present invention, a movable mirror device with excellent characteristics can be easily provided. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of an example of a conventional playback device;
2 to 5 are longitudinal sectional side views of different embodiments of the movable mirror device of the present invention, each of the figures in FIGS. 2 to 5 is an exploded perspective view of the same, and FIGS. FIG. 9 is a connection diagram showing an example of the operating principle and driving mode of the movable mirror device of the present invention. D...Disk, O...Objective lens, Mt, MJ・
...Movable mirror, 1...Mirror, 2...Wire, 3...Mirror mounting body, 4°4a-4d...Permanent magnet, 5...Damper, 6,6a-6e...・Coil 7... Fixing member, 8... Set screw.

Claims (1)

[Scope of claims for utility model registration] ■ In the optical path between the light source and the optical information recording medium disk,
An optical information recording medium disk reproducing device including a movable mirror capable of performing jitter compensation and tracking compensation by being driven and controlled by a jitter correction control signal, a tracking control signal, etc. Within two planes that are orthogonal to each other and each plane includes the normal to the surface of the movable mirror,
A movable mirror is elastically supported so that it can be swung and moved around a single fulcrum, and a magnetic pole is attached integrally with the movable mirror to the opposite side of the reflective surface that is buttoned on the movable mirror. The permanent magnets are arranged so that the arrangement direction of the movable mirror is in the direction normal to the surface of the movable mirror, and the fixed member to which the elastic support member that elastically supports the movable mirror is fixed. The arrangement is such that a plane perpendicular to the normal to the surface of the mirror is divided into four equal parts around the swing fulcrum, and the coil axis of each coil is parallel to the normal to the surface of the movable mirror. and a fixed coil device having at least four coils attached so as to maintain a non-contact state with the above-mentioned permanent magnet, and each of the coils buttoned on the above-described fixed coil device has a current flowing through each coil. optical information that generates an electromagnetic force of attraction or repulsion in the direction normal to the surface of the movable mirror between a magnetic field generated by a current of a predetermined direction and magnitude and the magnetic pole of the above-mentioned permanent magnet. A movable mirror device in a recording medium disk playback device. 2. A movable mirror for an optical information recording medium disk reproducing device according to claim 1 of the registered utility model, in which a space is provided between the end of a permanent magnet and the tip of each coil in a fixed coil device. Device. 3. A movable mirror device for an optical information recording medium disk reproducing device according to claim 1, wherein the magnetic pole at one end of the permanent magnet is located inside a coil of a fixed coil device.