JPH02220231A - Optical disk device - Google Patents

Abstract

PURPOSE:To stably support an optical head and to stably perform a head driving by arranging a fixed part face to face with a voice coil motor sandwiching a spindle and forming an optical path where the outgoing light beam from the fixed part can not be shielded. CONSTITUTION:The fixed part 2 and the voice coil 6 are arranged face to face so as to sandwich the spindle 1. Since the fixed part 2 is arranged on the side opposite to the optical head 4 so as to sandwich the spindle 1, the size of the moving coil 6 in an advance and retreat direction can become larger by lengthening a magnetic circuit 5. The fixed part 2 is fixed on the opposite side to the head 4 so as to sandwich the spindle 1 in the advance and retreat direction of the head 4 and also fixed on a chassis 12 so that the optical axis of outgoing and incident light beams may be parallel with the advance and retreat direction of the head 4 and also deviated from the spindle 1 to the other side against the circuit 5 and allowed to pass through the spindle 1 side. Thus, the optical axis from the fixed part 2 to a mirror and the optical axis between the mirror and the head 4 are not shielded by an obstruction, so that the laser light beam between the fixed part 2 and the head 4 can be smoothly transferred.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to stably support an optical head on a boil coil motor in an optical disc device using a separated optical system. The fixed part and the voice coil motor are arranged to face each other with the spindle in between, and the light emitted from the fixed part passes through the side of the spindle and enters the optical head via a mirror provided on the carriage of the voice coil motor. In addition, the mirror and the optical head are arranged at symmetrical positions with respect to the movement axis of the voice coil motor, and the weights of both are balanced.

[Industrial application field]

The present invention relates to an optical disc device, and more particularly to an optical disc device using a separate optical system.

[Conventional technology]

FIG. 5 is a plan view of the main parts of a conventional optical disc device.
FIG. 6 is a sectional view taken along line BB in FIG. 5.

In FIGS. 5 and 6, the optical system includes a fixed part (2) that emits and enters a laser beam, and a fixed part (2) that emits and enters a laser beam.
A separate type optical disc device is used, which is separated into an optical head (4) that transmits and receives a laser beam to a predetermined position on a disc plate. This optical head (4) is powered by a voice coil motor (hereinafter referred to as VCM) (3") as shown below.
By using the separate type, the acceleration during driving is increased and access speed can be increased. The fixed part (2) is driven by a spindle motor and supports a spindle (
1), and a laser beam is emitted toward the spindle (1). A boil coil motor (3') is disposed between the fixed part (2) and the spindle (1) to drive the optical head (4). That is, the optical axis (
parallel to the L) direction, and symmetrical with the optical axis (L) (fifth
A pair of magnetic circuits (5) are arranged vertically (symmetrically in the figure), and a moving coil (6) is slidably inserted into each magnetic circuit (5). These two moving coils (6) are connected by a carriage (8) with an optical head (4) mounted in the center, forming a so-called twin-body type head drive structure.

This carriage (8) has a pair of guide rails (7) placed on both sides of the magnetic circuit (5) (top and bottom in Figure 5).
) in the direction of the optical axis (L).

That is, as shown in FIG. 5, the front (
Bearings (9) are rotatably supported at three locations in the center of the rail (bottom of Fig. 5) and both ends of the rear (top of Fig. 5). By making contact from two directions, upward and diagonally downward, the longitudinal and vertical positions of the carriage (8), moving coil (6) and optical head (4) with respect to both rails (7) are maintained constant. Ru.

In this structure, by passing a current in either the forward or reverse direction through the moving coil (6), the optical head (4
) will be driven forward and backward with respect to the spindle (1). Furthermore, the optical axis (L) of the output and input of the fixed part (2) is arranged so as to coincide with the center line of the optical head (4) in the advancing and retracting direction, so that the spindle (1)
Laser beams can be exchanged between the fixed part (2) and the optical head (4) over the entire forward and backward stroke of the optical head (4), which is driven forward and backward toward the fixed part (2).

[Problem to be solved by the invention]

By the way, in these conventional examples, the optical head (4
) and the fixing part (2) are arranged on the same side of the spindle (1), the length of the magnetic circuit (5) is limited and therefore only by a distance corresponding to 1/4 of the prescribed disc plate. In order to access the optical head (4), the dimensions of the optical head (4) and the moving coil (6) in the moving direction must be reduced, which makes the support of the moving coil (6) unstable. In addition, since it is a twin body type, when a difference in driving force occurs between the two moving coils (6), the directionality of the optical head (4) is impaired, making it difficult to move the optical head (4). There is.

The present invention has been made in view of the above-mentioned circumstances, and provides an optical disc device that uses a separate optical system and is capable of stably supporting the optical head on the VCM and driving the optical head in a stable manner. The purpose is to provide the following.

[Means to solve the problem]

The present invention takes the following measures in order to achieve the above object in an optical disc device using a separate optical system.

That is, as shown in Fig. 1, the fixed part (2) and the voice coil motor (3) are arranged opposite to each other with the spindle (1) in between, and the light emitted from the fixed part (2) is directed towards the spindle (1). It is configured so that the light passes through the side and enters the optical head (4) via a mirror (10) provided on the carriage (12) of the voice coil motor (3). Further, the mirror (10) and the optical head (4)
It is preferable that they are arranged at symmetrical positions with respect to the movement axis of the voice coil motor (3), and that their weights are balanced.

[Effect]

With the above configuration, the fixed part (2) is placed on the opposite side of the optical head (4) across the spindle (1), so the magnetic circuit (5) is lengthened and the moving coil (6) is moved in the forward and backward direction. Size can be increased.

Also, at this time, the optical axis (Ll) from the fixed part (2) to the mirror (lO), and the optical axis (Ll) from the fixed part (2) to the mirror (10) and the optical head (4
) Since the optical axis (L2) between
The laser beam can be smoothly transmitted and received between the fixed part (2) and the optical head (4).

Furthermore, the optical head (4) and mirror (10) are connected to a VC.
By arranging them symmetrically with respect to M (3), the weight is balanced, and the propulsion force of V CM (3) pushes the center of gravity of the carriage (12), eliminating vibration of the optical head.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a plan view of an optical disc device according to an embodiment of the present invention, and FIG. 3 is a longitudinal section taken along the line AA in FIG.

This optical disk device consists of a spindle (1) that is rotated by a spindle motor (not shown) and supports a disk plate, a flat chassis (11) developed in a rectangular shape around this spindle (1), and a separate optical disk. It is equipped with a system. This separated optical system includes a fixed part (2) fixed to the upper surface of the chassis (11), and a single V CM (
3), and an optical head (4) which is driven back and forth in the left-right direction toward the spindle (1).

The movement axis of the V CM (3) is shifted forward (lower side in Figure 2) with respect to the spindle (1),
In addition, there is a only magnetic circuit (5) arranged parallel to the forward and backward direction of the optical head (4), and a moving coil (6) that is supplied with an externally controlled current and moves forward and backward along this magnetic circuit (5). ).

As shown in FIG. 3, the magnetic circuit (5) has a gap (5a) into which the moving coil enters when the laser beam is not blocked, and is parallel to the forward and backward direction of the optical head (4), and A pair of yokes (5b) connected at both ends
and (5c), and a magnet (5d) fixed to the upper surface of the lower yoke (5C), and the upper yoke (5b) and the magnet (
5d), a gear (5a) is formed between the two.

The moving coil (6) is connected to the upper yoke (5).
b) is slidably inserted into.

The spindle (
1) side end, that is, the front end has a carriage (12
) is fixed. This carriage (12) is projected on both sides of the moving coil (6) (up and down in FIG. 2), and the optical head (4) is fixed to the projection on the rear side (upper side in FIG. 2). .

In addition, the front protrusion of the carriage (12) has a moving coil (6) that reflects the light on the optical axis (Ll) of the fixed part (2) at a position symmetrical to the optical head (4) as shown below. U-(lO) is fixed.

A pair of rails (7) are provided in parallel with the magnetic circuit (5) before and after the VCM (3) (top and bottom in Figure 2), and the VCM
Bearings (9) that are rotatably connected to the rails (7) are rotatably attached to three locations at the center of the rear side of the carriage (12) and both left and right ends of the front side of the carriage (12). (12) is supported by the rail (7).

The fixing part (2) is located on the opposite side of the optical head (4) across the spindle (1) with respect to the forward and backward movement direction of the optical head (4), that is, on the left side of the spindle (1) in FIG.
Also, the optical axis (Ll) of the output and input is the optical head (
4) parallel to the advance/retreat direction of the magnetic circuit (5), and further away from the spindle (1) than the magnetic circuit (5) (lower side in Figure 2)
It is fixed to the chassis (11) so as to be offset from the spindle (1) and pass along the side of the spindle (1).

FIG. 4 is a perspective view showing the main part of the optical path of this optical system.

As shown in FIG. 4, the mirror (10) reflects the laser beam transmitted and received between the fixed part (2) and the optical head (4) from one side to the other. On the other hand, the optical axis (L2) between the mirror (1o) and the optical head (4) is configured to pass through the gap (5a). The light ray is reflected by this mirror (10), and the reflected ray (
b2) passes through the gap (5a) and the optical head (4)
The mirror (4a) built in is irradiated, and this mirror (4a) is irradiated with light.
4a), a beam (b3) for irradiating the optical disk is formed by reflecting the beam in a direction parallel to the axis of the spindle (1) (that is, upward). Note that this irradiation light beam (b3) is converged by an objective lens (4b) built into the optical head (4) and is irradiated onto the disk plate.

In this optical disk device, since the fixed part (2) is placed on the opposite side of the VCM (3) across the spindle (1), it is possible to make the length of the magnetic circuit (5) sufficiently large. The moving coil (6
) in the advance/retreat direction, thereby increasing the distance between the two left and right bearings (9) on the front side (lower side in Figure 2) that support the carriage (12) on the rail (7). Then move the moving coil (6) to the rail (7)
can be supported stably. Also, a single VC
M, the front and rear width of the carriage (12) (vertical convergence in Figure 3) is small, and the unbalance of driving force that occurs in the case of a twin-body type VCM does not occur, so the stable type described above is encourage Furthermore, by balancing the weight of the optical head (4) provided on one side of the moving coil (6) and the mirror (10) provided at a symmetrical position, the carriage is positioned at the center of the moving axis of the moving coil (6). (12
), the center of gravity of the carriage (12
) can move forward and backward in a stable manner.

Note that the optical axis (Ll) of the fixed part (2) is aligned with the spindle (
1) so that it passes along the side of the optical head (4) in parallel with the forward and backward direction of the optical head (4), so that the fixed part (2) and the mirror (
10) The light beam (bl) exchanged between the spindle (
1), there is no risk of it being blocked by the mirror (
The light beam (b) exchanged between the optical head (4) and the optical head (4)
2) passes through the gap (5a) of the magnetic circuit (5), so there is no fear that the light beam (b2) will be blocked by V CM (3).

〔Effect of the invention〕

As described above, according to the optical disc device using the separated optical system of the present invention, the carriage can be lengthened and its support can be stabilized. By balancing the weight of the optical head provided on one side of the VCM and the mirror provided on the opposite side, it is possible to align the center of gravity of the carriage with the axis in the advance/retreat direction.

Furthermore, since it is a single VCM, the center of gravity of the carriage can be pushed, so the optical head does not move.

be.

In the figure, 1... spindle, 3...VCM.

5...magnetic circuit, 6... Moving Co. 2...Fixed part, 4...optical head, 5a... gap, Ile,

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is a plan view of an optical disk device according to an embodiment of the present invention, and FIG. 3 is a line A-A in FIG.
FIG. 4 is a perspective view showing the main part of the optical path of the optical system, FIG. 5 is a plan view of the main part of the conventional system, and FIG. Figure % [IC-C line front diagram

Claims (1)

[Scope of Claims] [1] A fixing part (2) of an optical system that is fixed at a predetermined position with respect to a spindle (1) that supports an optical disk, and an optical system that transmits and receives a laser beam to and from the fixing part (2). In an optical disc device using a separate optical system separated into an optical head (4) that is driven forward and backward toward a spindle (1) by a voice coil motor (3), the fixed part (2) and the voice coil motor ( 3) are arranged facing each other with the spindle (1) in between, while the fixing part (2
) so that the light emitted from the spindle (1) passes through the side of the spindle (1) and enters the optical head (4) via a mirror (10) provided on the carriage (12) of the voice coil motor (3). An optical disc device comprising: [2] The optical disc device according to claim 1, wherein the mirror (10) and the optical head (4) are arranged at symmetrical positions with respect to the movement axis of the voice coil motor (3), and the weights of both are balanced. .