JPS5853032A - Reproducer for optical information recording disc - Google Patents

Abstract

PURPOSE:To attain accurate tracking, through the adjustment of a current by supporting a coil formed with electric wires wired in crossing with four pins at the four corners and a center fulcrum of a moving plate formed incorporatedly with a mirror, in a magnetic path freely shakingably. CONSTITUTION:A support shaft 11 is provided at the lower center of a moving plate 10 incorporated with a mirror 1 and supported freely shakingably in a round hole 13 of a damper 12 made of rubber provided at the center of a pole piece member 9. Four pins 13a-d are fitted at the four lower corners of the moving plate 10, electric wires surrounding the four pins in a quadrilateral and tying diagonal lines form a coil and the wires are connected to leads 16 and 17. The said coil is inserted in an air gap of the magnetic path consisting of a permanent magnet 8, a yoke 3, yoke planes 5,5' and 6,6', and pole pieces 9a-d. The direction and magnitude of current flowing to the coil are controlled and the mirror 1 is displaced, allowing to control the spot of a laser light for accurate tracking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reproducing device for an optical information recording disc,
More specifically, the present invention relates to a drive control device for a rotating mirror provided in an optical pickup system.

Optical video discs and digital audio discs (
Hereinafter, these optical information recording disk bodies will be simply referred to as disks. ) is equipped with an optical pickup that irradiates a light beam from a laser light source in a spot shape toward the recording surface of the disk through an objective lens, and detects the reflected light and transmitted light. This optical pickup is provided with several servo control means in order to prevent erroneous detection due to surface runout or eccentricity of the disk. In other words, it is automatic focus control of the objective lens due to surface runout of the disk, and tracking control so that the light spot always traces the planned information track.
It is also a speed error correction control (jitter correction control) in the tangential direction to the information track caused by disk eccentricity or the like. Of these, automatic focus control is performed by moving the objective lens and its lens barrel in the front and back direction along the optical axis, but the following two methods are known for tracking control and jitter correction control. A first rotating mirror called a tangential mirror and a second rotating mirror called a tracking mirror are placed in the path of the light from the 11-ray f light source to the objective lens. ...Moving the light spot on the first rotating mirror ζ iron disk surface in the tangential direction of the information trunk,
On the other hand, the beam spot of the second rotating mirror 1 is swung in the radial direction of the disk to cause the beam to accurately follow the information track.

(2) In addition to automatic focus control by moving the lens barrel that holds the objective lens in the axial direction (Z-axis direction), the lens barrel itself can be swung in the X-axis and Y-axis directions to create a single device. automatic focus control, tracking control, and jitter correction control (for example, Japanese Patent Laid-Open No. 5
4-24002).

In that case, in the conventional example (1) above, separate control devices are required for each of automatic focus control, tracking control, and jitter correction control, and the optical system is not complicated; The drawback was that adjustment was difficult. On the other hand, according to the method (2) above, the so-called three-axis correction can be performed with one device, so although the drawback regarding the above (1) is solved, the controlled member including the objective lens and its lens barrel is The mass becomes quite large, leading to practical problems such as mechanical resonance.

In addition, structurally, the X-axis circumferential coil, Y-axis circumferential coil, and Z-axis circumferential coil must be arranged within a narrow magnetic gap, which requires extremely high assembly accuracy and generates a large amount of leakage magnetic flux. It includes the problem of becoming.

The present invention was made in view of the above-mentioned drawbacks of the conventional apparatus, and its object is to provide an optical information recording disk having an optical pickup in which tracking control and jitter correction control are performed by a single rotating mirror. The purpose is to provide a body regeneration device.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

A rotary mirror 1 in this playback device is placed in the optical path of an optical pickup that includes a laser light source (not shown) and an objective lens 1, and is controlled by a drive control device 2 in either the X-axis direction or the Y-axis direction. It is configured so that tracking control and jitter correction control of the light beam irradiated from the laser light source can be performed simultaneously. That is, the drive control device 2 includes a box-shaped yoke 3 made of a magnetically permeable material such as pure iron. The upper surface of the yoke 3 is provided with an opening 4 having a substantially square shape. In this case, two pairs of yoke surfaces 5, 5' and 6, 61 facing each other are formed on each side of the opening 4. In this embodiment, one yoke surface 5
, 5' are the X-axis circumferential yoke surfaces, and the other yoke surfaces 6, 6'
are used as Y-axis yoke surfaces, and radially extending slits 7 are provided at adjacent corners thereof. Further, a permanent magnet 8 magnetized in the vertical direction is provided at the center of the bottom of the box-shaped yoke 3. This permanent magnet 8 has a pole piece member 9 placed above it. This pole piece member 9 has four sections facing each of the yoke surfaces 5, 5' and 6, 6'.
Two pole pieces 9a to 9d are provided. As shown in FIG. 2, each pole piece 9a to 9d is
They are mutually formed in a triangular shape so that an X-shaped passage is formed between them, and their hypotenuses face each of the yoke surfaces to form a uniform DC magnetic gap therebetween. On the other hand, this drive control device 2 includes a rectangular movable plate 10 to which the above-described rotating mirror 1 is attached. The movable plate 10 has a support shaft 1 which extends downward at its center, and is inserted into a round hole 13 of a damper 12 made of rubber or the like provided at the center of the pole piece member 9 via this support shaft 11. It is swingably mounted on the Moreover, four pins 13a to 13d are provided at the four corners of the movable plate 10, and are located at each vertex of a square and are formed to protrude downward from the positions. Each of these pins 13a = 13d has a first
The coil 14 and the second coil 15 for driving the Y-axis are wound in a cross-shaped manner. That is, as shown in FIG. 3, the first coil 14 is connected to the pin 13a.
→ 13c → 13d → 13b → 13a are wound around the pin 4 a predetermined number of times in a figure 8 pattern, and as a result, the pin 13a,
A parallel coil is formed between 13b, 13c, and 13d. Similarly, second coils 1513a, 13d and 13b
, 13c are formed between the parallel coils. Note that each of the pins 13 and the support shaft 11 are preferably made of non-magnetic material. Reference numerals 16 and 17 are coil terminals of the first coil 14 and the second coil 15.

In the above configuration, if the permanent magnet 8 is magnetized so that the lower part is the N pole and the upper part is the S pole, each yoke surface 5, 5', 6, 6' and each pole piece 9a to 9d A direct current magnetic gap is formed between the yoke surface and the pole piece. The movable plate 1o supporting the rotating mirror 1 is arranged such that the support shaft 11 is arranged such that the parallel coils of the first coil 14 and the parallel coils of the second coil 15 are disposed within corresponding magnetic gaps. It is mounted on the damper 12 via the damper 12. In this case, the X-shaped intersecting portions of the first and second coils 1.4.15 are accommodated in the X-shaped passage formed between each pole piece. For convenience of explanation, the direction in which the pole pieces 9a and 9b are arranged is the X-axis direction, and the two pole pieces 9
Let the direction in which c and 9d are arranged be the Y-axis direction. Therefore, when a control current is supplied to the first coil 14, a current flows in the same direction in the parallel coils in each magnetic gear between the yoke surface 5 and the pole piece 9a, and between the yoke surface 5' and the pole piece 9b. Electromagnetic forces occur in opposite directions. Therefore, this electromagnetic force causes the movable plate 10 to swing in the X-axis direction with the Y-axis as the rotation axis. Similarly, when a control current is supplied to the second coil 15, electromagnetic forces in opposite directions are generated in the parallel coils, which causes the movable plate 10 to rotate in the Y direction with the Y axis as the rotation axis.
Swings in the axial direction. However, in reality, the first coil 1
4 and the second coil 15 are simultaneously supplied with a control current,
As a result, the movable plate 10, that is, the rotating mirror 1, is rotated in the direction of the composite vector of electromagnetic forces generated in each of the parallel coil portions. Here, if the X-axis direction is used as a tracking control direction for a light spot on a disk (not shown), and the Y-axis direction is used as a jitter correction control direction, the rotary mirror 1 can perform both controls at the same time. In addition, FIG. 4 shows another embodiment of the present invention. That is, in this embodiment, a third coil 18 is provided in addition to the first and second coils 14 and 15 wound in a cross-over manner via each pin 13a=13d as described above. ing. This third coil 18 is wound in a square shape along each pin 13a to 13d, and when a control current is applied to the coil portion, the movable plate 1
An electromagnetic force is generated that moves the entire 0 upward or downward. Therefore, by providing the third coil 18 as described above, the rotating mirror 1 can also be controlled in the vertical direction, that is, in the Z-axis direction.

As is clear from the above description of the embodiments, according to the present invention, tracking control and jitter correction control of the light beam emitted from the laser light source can be performed by one rotating mirror. Therefore, in the optical pickup of this playback device, it is only necessary to arrange one rotary mirror in the light beam path from the laser light source to the objective lens, and compared to the conventional example (1) described above, the optical system and This can be achieved by simplifying the configuration of the control device itself. On the other hand, it is relatively superior in terms of practicality compared to the conventional example (2) above, in which the objective lens device incorporates a surf control system for focus control, tracking control, and jitter correction control. In other words, in the conventional example, three coils for three-axis correction must be arranged in a narrow space within the objective lens device, which makes the structure complicated, and the structure includes the objective lens and its lens barrel. Controlling a large mass body is actually quite difficult. On the other hand, although the present invention requires only one rotating mirror, its configuration is simple, and the mass of the mirror, which is the controlled object, is considerably 71% smaller. Accurate control becomes possible. In addition, according to this drive control device, since the cylindrical yoke is provided inside the coil bobbin, leakage magnetic flux is minimized (
Furthermore, by forming a pole piece around the X-axis and a pole piece for the Y-axis on the magnetic yoke, reliable operation separation between X-axis control and Y-axis control can be obtained.

Note that, unlike the above embodiment, it goes without saying that the rotary mirror may be attached to the coil bobbin at an appropriate angle.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotary mirror drive control device used in an optical pickup of a reproducing device according to the present invention, and FIG. 2 is a plan view showing a state in which the movable plate in FIG. 1 is removed.
FIG. 3 is a drawing showing the winding state of the coil attached to the movable plate, and FIG. 4 is a drawing showing another embodiment. In the figure, 1 is a rotating mirror, 2 is a drive control device, 3 is a yoke, 4 is an opening, 5.5', 6.6' are yoke surfaces, 8 is a permanent magnet, 9a to 9d are pole pieces, 10 is a movable plate, 1
1 is a support shaft, 12 is a damper, 13a to 13d are pins, 1
4.15 are the first and second coils. Patent Applicant: Audio Technica Co., Ltd. Patent Attorney Takuya Ohara Procedural Amendment (Method) Commissioner of the Patent Office Shima 1) Haru Jumei 1 Display of the Case 1982 Patent No. 1 No. 152311z, issued by Fu (
D Name Reproducing device for optical information recording disc 3, Patent applicant related to the case of the person making the amendment 4, Agent Address: 102 0407 March 9, 1987 Commissioner of the Japan Patent Office Shima 1) Haru Judono 1. Indication of the case 1981 Patent No. 115.2311 2. Invention “Name N” Reproducing device for optical information recording disc 3. Person making the amendment Relationship to the case Patent applicant 4. Agent 102 5. Date of amendment order (voluntary)

Claims (1)

[Scope of Claims] A light beam from a light source is reflected by a rotating mirror and is incident on an objective lens, and the light beam is irradiated in a spot shape toward a recording surface of an optical information recording disk through the objective lens. A reproducing device having an optical pickup, which includes: a movable plate that supports the rotating mirror and has four pins arranged at each vertex of a square; and a bearing means that swingably supports the movable plate. the first and second coils are wound in a cross-over manner so as to form two pairs of parallel coils facing each other along each of the pins;
a yoke member having four yoke surfaces formed in relation to and parallel to the pair of parallel coils, and arranged opposite to each of the yoke surfaces so as to form a magnetic gap perpendicular to the parallel coils; a pole piece, and a magnetism generating means interposed between the yoke member and the pole piece, the control current is supplied to the first and second coils, and the electromagnetic force generated in each of the parallel coils 2. A reproducing apparatus for an optical information recording disk body, comprising a rotating mirror drive control device for swinging the rotating mirror in an arbitrary direction about the fulcrum of the bearing means.