JPS61206934A - Optical head actuator - Google Patents

Abstract

PURPOSE:To make an optical head thin and make it difficult to transmit the oscillation from a spindle motor and a voice coil motor to the optical head by storing a focusing actuator in the optical head. CONSTITUTION:With respect to the structure of a galvanomirror 44, a magnet 48 is set in a notched part of a yoke 47 whose section is a mountain shape, and a coil 49 is inserted to a projecting part of the yoke 47. A focusing actuator 43 has a notched part 52 in the lower part, and an objective lens storage part 54 which has an objective lens attaching part 53 in the upper part and has a U-shaped section has one end fixed to a fixing part 101 of an optical head 41 and is held by a pair of flat springs 55 extended in the radial direction of a disc 46. Since the galvanomirror 44 and the focusing actuator 43 are arranged on the same plane on a carriage 42, the focusing actuator is stored in the carriage, and the optical head is made thin.

Description

[Detailed Description of the Invention] [Summary] A focusing actuator of a seven-door optical actuator and a galvanometer mirror are installed on the same plane on a head carriage housing an optical head, and the focusing actuator is installed on the carriage. The optical head is composed of a reflecting mirror, a leaf spring that extends from the fixed part of the optical head, an objective lens accommodating part that is held by the leaf spring and houses the objective lens, and a coil and a magnetic circuit that move the leaf spring in the disk focusing direction. By energizing the coil, the objective lens moves in the disk focusing direction together with the objective lens accommodating portion.

Furthermore, a rotation center axis for rotating the reflecting mirror of the galvanomirror is disposed along the disk focusing direction,
The reflecting mirror rotates around the rotation center axis, and the light reflected by the reflecting mirror is reflected by the reflecting mirror of the focusing actuator with the optical axis polarized by 90 degrees.

Furthermore, by introducing this reflected light into the objective lens of the focusing actuator, a thin optical radar is formed.
To obtain a highly reliable optical disc device in which resonance phenomena caused by vibrations from a spindle motor that rotates an optical disc and a voice coil motor that drives an optical head are reduced.

[Industrial application field]

The present invention relates to an optical disk device, and more particularly to an optical disk actuator having a thin structure.

Applying a photosensitive agent onto a disk-shaped substrate such as glass epoxy resin, irradiating the photosensitive film with a light beam such as a laser beam to melt the photosensitive film in a predetermined pattern, and removing the melted portion. information is recorded to form an optical disc.

An optical disk device that reproduces information by irradiating this optical disk with a laser beam and detecting the intensity of reflection of the light from the portion of the photoresist film that has been melted and removed is well known as a high-density information recording device.

When such an optical disk is installed on a rotating shaft and information is recorded or reproduced using a laser beam while rotating the rotating shaft, the laser beam is focused on the recording surface of the optical disk. It is also necessary to control and focus the light onto a predetermined track position on the optical disc. It is desired that the optical head actuator used for this purpose be made as thin as possible to reduce the resonance phenomenon caused by the spindle motor that rotates the optical disk and the voice coil motor that drives the optical head actuator.

[Conventional technology]

FIG. 4 is a schematic diagram of a conventional optical disk device. As shown in the figure, an optical disk 2 is rotated by a spindle motor 1.
and an optical drive 7 mounted on a hend carriage body 4 that moves parallel to the optical disc 2 by a voice coil motor 3.
It consists of 5.

The optical head 5 includes an optical device 6 consisting of a laser light source, a condensing lens, a beam splitter, etc., and a galvanometer mirror 7 for focusing the laser beam irradiated from this optical device onto a predetermined track position on the optical disc 2. optical disc 2
and a focusing actuator 8 for controlling the focal point and focusing the laser beam on the surface of the laser beam.

An assembled configuration diagram of a conventional focusing actuator is shown in FIG. 5, and a sectional view of this assembly configuration diagram is shown in FIG. 6.

As shown in FIGS. 5 and 6, an objective lens 11 for condensing laser light is arranged in a concentric circle with bobbin coils surrounding it.
2 is inserted into the central opening 14 of the frame-like member 13 provided with 2. Furthermore, this frame member 13 has an opening 15 in the center, and a U-shaped cutting part 16 is provided around the opening 15, and a disc-shaped yoke 17, a disc-shaped magnet 18, and a disc-shaped cutting part 16 are provided around the opening 15. The opening 15 of the magnetic circuit 2o has a yoke 19 laminated thereon.
is inserted into.

By energizing this coil 12, the frame member 13 moves up and down due to the magnetic field formed along the gap between the yoke 17 and the coil 12, and the focus of the laser beam irradiated onto the optical disc 2 is brought into alignment. The objective lens 11 moves to a predetermined position.

FIG. 7 shows an assembled configuration diagram of a conventional galvano mirror.

As shown in FIG. 7, a yoke 21 having a mountain-shaped cross section, a magnet 23 inserted into a notch 22 of this yoke 21, and a coil 25 inserted into a protrusion 24 at the center of the yoke 21. A mirror support 27 made of a flat plate-shaped non-magnetic material is installed close to this coil 25 and has a rotating shaft 26 installed thereon.
A reflecting mirror 28 is attached to.

By controlling the current flowing through the coil 25, the mirror support 27 is rotated by the rotating shaft 26 in the direction of the coil 25, and the mirror support 27 is controlled and moved to a predetermined tracking position of the optical disc by this moving distance. become.

FIG. 8 is a schematic diagram of a conventional focusing actuator 8 and galvano mirror 7 installed in the optical head 5. As shown in the figure, the rotation axis 26 of the galvano mirror 7 is parallel to the surface of the optical disc 2. The laser beam 31 irradiated from the optical device 6 is arranged to be incident on the reflection mirror 28 at an incident angle of 45 degrees.

In addition, the focus actuator 8 is a galvanometer mirror.
It is located directly above 7. The dimension 7!1 of the bottom of the optical head 5 of this galvano mirror 7 from the carriage 4 is:
The vertical dimension 12 of the focus actuator 8 is 12 to 13 meters, and the sum of the dimensions of the focus actuator 8 and the galvano mirror 7 is 27 to 29 meters.

[Problem that the invention seeks to solve]

Therefore, the focusing actuator 8 protrudes from the optical head 5, and the center of gravity of the optical head 5 moves upward, and the voice coil motor 3 moves the optical head 5.
There is a problem in that when the optical head 5 is moved and stopped at a predetermined track position, the vibration of the optical head 5 does not stop easily.

In addition, the vibration of the spindle motor 1 that drives the optical disk 2 is easily transmitted to the optical head 5.
This causes a phenomenon in which the optical head resonates due to the vibration of the spindle motor 1, which makes it impossible to control and install the optical head at a predetermined trunk position.

Furthermore, when a plurality of optical discs 2 are stacked to achieve higher density recording, if the dimension of the optical disc 5 in the perpendicular direction to the optical disc 2 is large, the entire optical disc device becomes large. arise.

[Means for solving problems]

FIG. 1 is a schematic diagram of an optical head actuator according to the present invention.

As shown in the figure, the optical head actuator of the present invention is
Focus actuator 43 and galvano mirror 4
4 are installed on the same plane on a head carriage 42 that accommodates an optical helad 41.

This focusing actuator 43 is connected to the objective lens 6.
0, a 45-degree reflecting mirror 59 disposed directly below the objective lens 60 and fixed on the carriage 42 of the optical head, and a leaf spring 55 extending in the disk focusing direction from the fixing part (101) of the optical head. A gap portion of a magnetic circuit formed by an objective lens accommodating portion 54 that accommodates the objective lens 60, a yoke 56 held in the objective lens accommodating portion 54 and a part of which is placed on the carriage 42, and a magnet 57. It consists of a coil 58 inserted into the By energizing this coil 58, the coil 58
is moved in the disk focusing direction, and the objective lens 60 is also moved in the disk focusing direction. Further, a rotation center axis 45 for rotating the reflecting mirror 51 of the galvanometer mirror 44 is arranged along the disk focusing direction.

Further, a reflecting mirror 51 constituting the galvanomirror 44 rotates around the rotation center axis 45, and the light reflected by the reflecting mirror 51 is transferred to the reflecting mirror 5 of the focusing actuator 43.
At 9, the optical axis is polarized by 90 degrees, reflected, and introduced into the objective lens 60 of the focusing actuator 43.

[Effect]

That is, in the optical seven-door actuator of the present invention, a galvano mirror 44 and a focusing actuator 43 are installed on the same plane of a carriage 42 on which an optical head 41 is installed, and a mirror rotation axis 45 of the galvano mirror 44 is used for focusing an optical disk 46. Install it so that it is parallel to the direction. It is also fixed to the fixed part of the optical helad 41,
An objective lens accommodating portion 54 is provided which is held by a leaf spring 55 extending along the radial direction of the disk 46.

The objective lens accommodating portion 54 has a notch 52 at the bottom, an opening 53 at the top, and has a U-shaped cross section.

An objective lens 60 is embedded in the opening 53 of the objective lens accommodating portion 54, and a 45-degree reflecting mirror 59 is disposed in the notch 52 directly below the objective lens 60, so that the dimension of the objective lens 60 in the focusing direction of the optical disk 46 is adjusted. Make the appearance smaller. Further, a coil 58 is provided in the lens accommodating portion 54, and a part of the coil 58 is inserted into the gap of a magnetic circuit formed by a yoke 56 and a magnet 57 installed on the carriage 42, and a current is applied to the coil 58. The objective lens 60 is controlled to move to a predetermined focusing position on the optical disc 46.

In this way, it is possible to obtain an optical head with a thinner structure than the conventional device by the size of the focusing actuator.

〔Example〕

FIG. 1 is a perspective view showing the structure of an optical disk device equipped with the optical head actuator of the present invention, FIG. 2 is a configuration diagram of the optical head actuator of the present invention, and FIG. 3 is a diagram of the structure of the optical head actuator of the present invention. It is an assembly diagram of the focus actuator inside.

To explain FIG. 1 in more detail, in the optical radar actuator of the present invention, a focusing actuator 43 and a galvanometer mirror 44 are installed on the same plane on a carriage 42 that accommodates an optical head 41.

A mirror rotation axis 45 of this galvanometer mirror 44 is installed parallel to the focusing direction of an optical disc 46 installed above the optical disc 41.

As shown in FIG. 2, the structure of this galvano mirror 44 is such that a magnet 48 is placed in a notch of a yoke 47 having a chevron-shaped cross section.
is installed, and a coil 49 is inserted into the protrusion of the yoke 47. Further, a mirror support 5o is installed close to the yoke 47, and this mirror support 50 is rotated by the rotation shaft 45 described above. Further, a reflecting mirror 51 is fixed to the mirror support 5o with an adhesive or the like.

Further, as shown in FIGS. 2 and 3, the focusing actuator 43 has a notch 52 at the bottom, and an objective lens accommodating section 54 having a U-shaped cross section and an objective lens mounting section 53 at the top. One end is fixed to the fixed portion 101 of the optical head 41 and held by a pair of leaf springs 55 extending in the radial direction of the disk 46 .

A yoke 56 is installed inside the leaf spring 55, a magnet 57 is installed in the yoke 56, and a coil 58 is installed around the yoke 56. The yoke 56 and the magnet 57 constitute a magnetic circuit.

A reflecting mirror 59 is inserted into the notch 52 of the objective lens accommodating part 54, and an objective lens 60 is installed in the objective lens mounting part 53.

By energizing this coil 58, the coil 58 moves in the disk focusing direction, which also moves the leaf spring 55, further moves the lens accommodating section 54, and moves the objective lens 60 in the disk focusing direction. It has become.

According to the structure of the optical actuator of the present invention, the laser beam 61 irradiated from the light source in the optical head is applied to the reflection mirror 51 installed at a predetermined tracking position of the optical disk by passing a predetermined current through the coil. It hits the mirror 59 and is reflected by the upper objective lens 60.
The light is focused on. If this reflecting mirror 59 is adjusted so that the angle of incidence and the angle of reflection of the incident light are 45 degrees, the laser beam reflected by the reflecting mirror 51 will move in the vertical direction and be focused on the objective lens 60. .

In this way, the galvanometer mirror 44 and the focus actuator 43 are arranged on the same plane on the carriage 42, so the focus actuator is housed within the carriage and the optical head is thinner than in conventional devices. becomes.

〔Effect of the invention〕

As described above, according to the optical head actuator of the present invention, the focusing actuator is housed inside the optical head instead of the conventional structure, a thin optical head can be formed, and the spindle tongue motor, voice coil motor This makes it difficult for vibrations from to be transmitted to the optical head, resulting in a highly reliable optical disc device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a seven-door optical actuator according to the present invention, FIG. 2 is a perspective view showing the configuration of main parts of an optical door actuator according to the present invention, and FIG. 3 is a configuration of a focusing actuator according to the present invention. Fig. 4 is a block diagram of a conventional optical disk device, Fig. 5 is a block diagram of a conventional focusing actuator, Fig. 6 is a sectional view of a conventional focusing actuator, and Fig. 7 is a block diagram of a conventional galvanometer mirror. FIG. 8 is a block diagram of a conventional optical head actuator. 1, 2 and 3, 41 is an optical head, 42 is a carriage, 43 is a focus actuator, 44 is a galvanometer mirror, 145 is a rotating shaft, 46 is an optical disk, 47.56 is a yoke, 48゜57 is a magnet, 4
9. 58 is a coil, 50 is a mirror support, 51 is a mirror, 52 is a notch, 53 is an objective lens mounting part,
54 is the objective lens housing part, 55 is the slope spring, 59 is the reflector, 60 is the objective lens, 61 is the laser beam, 101 is the first light source, and the liquid remains at the bottom. 9 shoulder 0zo ¥ -
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Claims (1)

[Scope of Claims] A head carriage (42) in which an optical head (41) is housed, including a focusing actuator (43) that drives a light beam spot in the disk focus direction and a galvanometer mirror (44) that drives the disk in the radial direction. The focusing actuator (43) is installed on the same plane as the plate spring (43) extending from the fixing part (101) of the optical head (41).
55), an objective lens accommodating part (54) held by the plate spring (55) and having a notch, and an objective lens accommodating part (54) held by the objective lens accommodating part (54) and driving the plate spring (55) up and down. a coil (58) and a yoke (56) housed within the leaf spring (55) and mounted on the carriage (42).
) and a magnet (57); an objective lens (60) housed in the objective lens housing section (54);
It consists of a reflecting mirror (59) installed on a carriage (42) directly below the objective lens (60), and a rotation center axis (45) for rotating the reflecting mirror (51) of the galvanometer mirror (44). The reflecting mirror (51) is arranged along the disk focusing direction, and rotates around the rotation center axis (45).
51) The optical head actuator is characterized in that the light reflected by the focusing actuator (43) is reflected by the reflecting mirror (59) of the focusing actuator (43) with the optical axis polarized by 90 degrees, and is introduced into the objective lens (60).