JPS5911544A - Optical head driving device - Google Patents

Abstract

PURPOSE:To attain the high speed accessing owing to the reduction in a mass of the entire moving section, by arranging fixedly a magnet device and forming a magnetic gap over the entire length of a head moving track in disc radial direction, for driving an optical head with a light focusing coil and a tracking coil. CONSTITUTION:Placing a moving coil 3 in a magnetic field having a direction shown in the arrow phi, then the direction of an electromagnetic force produced in focusing coils 1A, 1B is indicated by the arrow Ff on faces cdfe and ghba of the moving coil 3 when flowing a current to the focusing coils 1A, 1B in the direction of the arrow 1f, and the direction of the focusing force Ff is reversed by reversing the direction of the current If. In flowing a reverse current to tracking coils 2A, 2B similarly, the direction of the tracking force Ff is also reversed. Thus, the movement of a desired amount in the 1st and the 2nd directions is performed by the moving coil 3, by controlling the direction and amplitude of the current flowing to the focusing coils 1A, 1B and the tracking coils 2A, 2B.

Description

[Detailed description of the invention] The present invention relates to an optical head driving device f.

Regardless of whether the VC is for playback only or for both recording and playback, the optical disk drive is capable of keeping the distance between the pickup head's Ut + lens and the disk at a constant V (maintaining a constant V) in response to the vibrations of the disk rotating at high speed. Focusing method (load and disc-42 spiral or concentric information tracks VC product to track the original spot 1
A tracking mechanism that drives the head is essential.

Conventionally, each of these mechanisms has been embodied in a variety of ways,
For example, a method using one voice coil for focusing f4 and a tracking 1m VC galvano mirror, in directions orthogonal to each other! I! A system in which two voice coils are used for the focusing mechanism and a dragging mechanism, a system in which a voice coil is used in the force-song mechanism, and a system in which a linear motor is used, etc. are known.

However, in these conventional methods, even if the number of permanent magnets and the number of coils is Vrp,
The permanent magnet is made of iron-based old material and has a very attractive ratio, and since all the yokes are made of iron, the overall size of the head and tM
In fact, most of the weight of this type of head is accounted for by these permanent magnets and the yoke.

By the way, in the optical disc device tπ, the head structure including the focusing unit UMta and the tracking mechanism is fed and moved in the disc radial direction by a slider or the like driven by a lead screw, etc. It is necessary to set K so that information retrieval can be performed in a short time and at high speed.

Therefore, a large head drive mechanism as described above is unsuitable for this high-speed feed operation and imposes a π limit on the trunk's rapid access.

In addition, in the conventional head drive groove, the magnetic circuits for both focusing and tracking are separate, resulting in a complicated structure and a large number of parts.
It has also been pointed out that ,+1:bi Japanese text b''-troublesome)) is a drawback.

The purpose of the present invention is to reduce the weight of the optical head drive system in such an optical system and to simplify the H4 immersion process, including permanent magnets and yokes. It is an object of the present invention to provide an optical drive device having an advantageous structure such as fixed arrangement, high speed access, and high speed access by excluding iron-based parts from moving parts.

That is, the optical head driving device according to the present invention to achieve this purpose moves the A-science head along the trajectory vr p9.
In the optical head driving device that can move the optical disk in the radial direction, the front optical head is moved at an actual V (vertical) first position with respect to the optical disk.
and a second direction in the radial direction of the optical disk. It is equipped with a single force coil that moves in the first direction, the second direction, and the second direction, and an ib coil that can be integrated with the tracking coil.
Before #L'K 6b force is generated Tcomer (the magnetic field common to the focusing coil and the tracking coil), the magnetic gap which increases the total thickness is fixed on the 1st magnet device'tt, and the ζ from the trajectory vc iB and the entire orbit J〈
It is characterized by being formed over a period of time.

In the optical head drive device of the present invention, the movable coil constitutes a two-dimensional drive system that moves in two directions at an angle of K tM with respect to each other, and focusing of the objective lens is performed by displacement in the first direction. The recording track of the disk is tracked by displacement in the second direction. As a driving means for shifting the optical head in the same direction as the second direction, a slider type using a well-known lead screw K, a rank and pinion type, or a linear type can be used. A motor type one may also be used.

In particular, in the case of a linear motor system, the magnet device can be used as the magnetic system, and furthermore, the tracking coil can also be used as the linear motor.

In the optical head drive device @f of the present invention, the magnet device surface made of iron-based metal serves as a fixed side member, and the movable side member only includes a movable coil having a core.

Therefore, by reducing the purchasing price of the movable part, the faster access operation π
This makes it suitable for one person, and also simplifies the G reform itself.

The present invention will be described in detail below along with the illustrated embodiments.

FIG. 1 shows an optical head driving device i Vr according to the present invention.
-C shows the configuration of the moving coil as a dimensional drive system,
In the figure (1A) (I B)! Efocusing coil,
(2A) (2B) L Nidoranking coil. The focusing coil (IA) (I B) is shown in Figure 2 VC.
(,,')y ko(/l/Make the entire flat rectangular coil using a winding heddle, and bend it at right angles at the dotted line part (L) to make it into a "1-shaped" coil as shown in Figure 3. In addition, the tracking coil/2.A) (2B) is formed into a rectangular cylindrical coil as shown in Fig. 6f using a winding machine, and this can be formed by using a bobbin or by using a copper wire. Even if it is formed into a rectangular cylindrical V shape with adhesive, it will not be possible to form the square tube shape. , are integrated with adhesive etc. to form the moving coil (6) shown in Fig. 1.
). In addition, in Fig. 1 π, fal~(
For convenience of explanation, f and j are each vertex of the moving coil (6).

Now, in the magnetic field K in the direction shown by the arrow (φ) in Fig. 1 π,
Assuming that one coil (6) for ET is loaded, a current flows in the direction of the focusing coil (1A) (IB) π arrow (if) [7] When the surface cdf of the moving coil (6)
The focusing coil (IA
)(IB)x The direction of the generated electromagnetic force is shown by an arrow (Ff), and if the direction of the current (b) is reversed by π, the direction t of the focusing force (Ff) will also be reversed K tc. Similarly to the tracking coils (2!A) (2B), if a current flows in the direction of the π arrow ([t), the direction of the electromagnetic force due to π is the arrow (Ft).
As shown, 'current (It)' has a reverse direction K 1f
If it is, the direction of the tracking force ()'t) will also be reversed. Therefore, focusing coil (1A) (1B), tracking coil (2A) (2fl) and K? ICtN
The direction and size of the flow are controlled (required), and the electric current (1
To move the desired amount in the first direction by μ force (Ff) K and J-, to move the desired amount in the second direction by electromagnetic force (Ft) K, and to make the entire moving coil (6) perform one movement. can.

Here, it is conceivable that the tracking coils (2A) (213) give the focusing coils (IA) (IB) r an interference of equal action π, but in this case, the tracking coils (2A) (2B) K Ft1. If you set the direction and increase/decrease of the current (It) to be the same, the focusing coil (IA
)diY,=l! (113)6; The electromagnetic effects received are the same in magnitude but opposite in direction, resulting in mutual cancellation. Focusing coil (IA)
(113') is the tracking coil (2A) (2B)r
The frost applied to the magnetic field; the magnetic h4 effect can be similarly canceled out, and therefore there is no interference between the coils.

In addition, the movable coil (6) moves the focusing force (Ff) &(
Therefore, moving in the direction π of 141 fJ: shadow vf due to the change in the position of the magnetic field cut by the recoil, the tracking coil (2A) (213) does not produce a shadow V due to movement in the first direction b; without - In the cuff focusing coil (IA,) (IB) (movement in the first direction w causes the magnitude of the electromagnetic force (1'r) V(thilI++);, this movement for focusing The battalion 0 is not a big thing, and the magnitude of the variable axis of the electromagnetic force (Ff) is so small that it can be ignored in practical terms, so there is no problem.

In this way, the moving coil (6) is connected to the focusing coil (1A) (113) and the tracking jig coil (2A)C.
By excitation control 1141π with 2B), a two-dimensional drive coil can be constructed which allows focusing control and tracking control to be performed independently without causing interference between the coils] and with good linearity.

K, which constitutes an optical head using such a moving coil (6) for two-dimensional driving, is a 5π objective lens holder (4) V (moving coil (3) fd) as shown in FIGS. 4 and 5.
: The holder (4) is supported by the support system so that it can be displaced in the first and second directions π, respectively. In Fig. 4 π, (5) is a support member, on the inner surface of which a wheel-shaped protrusion (7) for positioning the coil is provided surrounding the through hole (6) in the center, and on the outer surface f has mounting parts (8) at the four corners.
/＋；lol It has been set up. The movable coil (3) rr is a rectangular hole (9) formed by the medium heat of the focusing coil (1-A) (1fJ). Support member (
5) is glued, and the holder (4
) is subjected to ν°f before adhesion as shown in FIG. In this case, the holder (4)K also has a square hole (10) into which the rectangular projection (7) is inserted.
), which makes it easy for the holder (4), the support part (5), and the movable coil (6) to come together easily. Fig. 5 When assembled as shown, the through hole (6) of the support member (5), the rectangular hole (9) of the moving coil (3), and the square hole (10) of the holder (4) are connected in series. The entire optical path of 7 (Fig. 45-C & Appearance 1r
In the holder (4), an objective lens and a beam splitter, for example, which constitute the optical system of the head (4), are arranged.
It is a flexible support such as a wire, and a pair of flryt lens bolts (4) and an AJt extrusion coil (6) are connected to each other between the first and second ILl.
It supports two angles of force, Vr, and positioning.

In the example of FIGS. 4 and 5, "IJ' moving coil (6)
The optical head consists of a support J, a holder (4), and a holder (5).
) and an elastic support (12), the two-dimensional freely displaceable support means for this optical head is not limited to this, and as another example, two pairs of parallel springs are shown in FIG. This figure shows a two-dimensional moving spring support consisting of.

In FIG. 6π, (13) is a two-dimensional spring support, which is a parallel focusing spring having a support portion (14) corresponding to the support member (5) K at its tip. (15) and a tracking parallel spring (16) in a direction perpendicular to this are integrated, and the support part (14) K
Attach the objective lens (11) and its inner surface fi11
A rectangular protrusion (17) similar to the rectangular protrusion (7) is provided.

Figures 7a and 7b are a partially cutaway plan view of a magnet device (indicated by the reference numeral (28)'t) for applying the magnetic field (φ) to the movable coil (3) VC of the optical head; h-, A cross-sectional view of a pair of long permanent magnets (
18a) (18b) have a north pole on the negative side and a south pole on the back side, and the yoke (19a) (19b) (20a) (
20b) (21a) (21b) and spacer (22a) (
22b) (23a) (23b) (24a) (24b) K
Therefore, the elongated magnetic gaps (25a) (25b) are shaped parallel to each other.

Assemble the holder (4) and install one 4h coil (6) in the cavities (26a) (26b) (Fig. Then gbba passes through the magnetic gap (25a) 1i
K so that the cdfe moves (ik1 gap (25b) inner metal) and the holder (4) moves to the yoke gap (27) inner metal.
This magnet assembly fiffi(28)r (combined).

Now, holder (4) is fully assembled and one moving coil (6) ffi
It is supported by the two-dimensional spring support Ff body π shown in Figure i6, and combined with the magnet device (28) Pζ shown in Figures 7a and 7b. This is the trace of Figure 8.

In FIG. 8f, the magnet device 1 (28) is fixedly arranged with its magnetic gap length direction facing the radial direction of the optical disk, and a linear guide (29) is attached to the magnet device (28). has been done. (60) is a slider that supports the two-dimensional parallel spring support (16) supporting the holder (4) (11 moving coils (6)) in a movable pT function with two linear guides (29) K? So, this slider (30) K &
The optical system is arranged according to the work required, and the slider (30)
In order to shift and move the slider (30) in the disk radial direction, a magnetic circuit (not shown) constituting a near motor with a magnetic circuit is attached to the slider (30).

FIG. 9 is a plan view showing another embodiment. In this example, the boulder (4) and the movable coil (3) are fully supported, and one
Attach the dimensional spring support (13)' to the tip of the rotation arm (62), and use the arm (62) as the rotation fulcrum (66).
Attach the near motor coil (64) for driving the lever to the arm tail end KL!!, and attach the magnet device (
65) is bent into an arc shape so that the head can be shifted in the radial direction of the disk.

8 and 9, the two-dimensional parallel spring support (1
6) is used as an example in this case. But it goes without saying that it's a good thing. Mako Slider (30) Yaarm (62)
) can be used, for example, a single linear motor type, a rank-and-binio type, or a lead screw type.

Figure 10 shows a modification f8 of the example in Figure 8, in which the magnetic circuit for the linear motor is connected to the magnetic device id' ((28)). iin' in the magnetic caps (25a') (25b) & Ti from the punishment: (+Get angry and let the sura [da (60) guide (29) stay overnight and move 1ii11 5 vi”
It is L-.

Figure 11 shows the two-dimensional free displacement means V (Seki-I Rusara prr).
Here's another example. Objective lens boulder (4) Tc
A'J1j-J digit moving coil (3) and objective lens (1
1 upper and lower support plate (56) &c 11! ! l 5i, and this upper and lower support plate (56) (7) four corners h (Vi'1170-
Install the lower part. Of the guide frames (38), one frame (38) is placed parallel to the CDFE in Figure 1.
38a) from this μm (57)π to support plate C66)
The entire guide frame (38) is parallel to nceg in FIG. ) RTR provided with tile V-shaped roller (6
C) π4 [Yoke (19a) of Izushi device 7 (28)
It is movable on the idle rail (40) above (19b). To this, J: magnetic gear rough (25a) (25b)
It is configured such that it can be displaced in a second direction for tracking in the length direction of π and can be shifted in the same direction. Note that (41) is a member that connects the guide frames (68) on both sides. In this case, if the shift movement is performed by the tracking coil, a rK movement mechanism such as a linear motor for separate f-shifting is unnecessary.

As described above, according to the present invention, the heavy magnet device is moved from shift 1 so that the magnet device is fixedly arranged and a magnetic gap is formed across the length of the head movement trajectory in the radial direction of the disk. Not required.The focusing coil and tracking coil used in K1 can drive the optical head, which reduces the mass of the entire movable part and enables high-speed access operation. This has the advantage of being simple.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the entire structure of the moving coil, which is the main part of the present invention; Fig. 2 is a first-order plan view illustrating the forming of the focusing coil σ; 4 is a perspective view of an objective lens holder and a support member, FIG. 5 is a perspective view of an example of an optical head assembly, and FIG. 6 is a perspective view of a secondary parallel spring support. , 7th
Figure a is a partially cutaway plan view showing an example of the I-sen device 11';
Figure 7b is a cutout σ) A-A - is a side view of the edge arrow, and Figure 8 is an optical head drive! Il device i7. &l-Perspective view showing an embodiment, stripe 9 shows another embodiment-J-Flat m7 view, Fig. 10 shows a modification f'llll of Fig. 8 No. 1]-r perspective view, Fig. Figure 11 is a perspective view showing another example of the two-dimensional freely displaceable support means. (IA) (IB): Focusing coil, (2A) (
2B);Dragging coil, (6): Moving coil, (
4): Objective lens holder, (5) Two support parts A, ), (6
): 1+A hole, (7): Rectangular protrusion, (8): Take (・1
Projection, (9); Rectangular hole, (10): Square hole, (11): Objective lens, (12): Bullet (raw support member, (13C two-dimensional parallel spring support i, ) t4-1 (18 Mori) (18b); Permanent magnet, (25a) (25b): m gap ~ (
N6); Grinding device surface, (N9): 1 White six edge guide, (6
O): Slighter-1 (31): Coil for linear motor, (32) Near-0m. Agent Patent Attorney Sanro Kimura Figure 6 Off Figure A

Claims (1)

[Scope of Claims] An optical head driving unit V having a track for moving the optical head in the radial direction of the optical disc (wherein the optical head is arranged in a first direction substantially perpendicular to the surface of the optical disc). an objective lens holder capable of displacing in two directions, i.e., in the direction of KffEr and a second direction in the radial direction of the optical disk; A movable coil assembly including a focusing coil and a tracking coil assembled to the holder is disposed over the entire length of the orbit, and a polishing coil is provided to apply a common magnetic field f to the focusing coil and the tracking coil in order to generate the electromagnetic force. An optical head drive device, which is characterized in that it has a stone device.