JPH0766586B2 - Multi-stage multi optical head for optical disk device - Google Patents

Description

The present invention relates to a multi-stage multi optical head for an optical disk device.

(Prior Art) Conventionally, an optical disk device has generally been equipped with one optical head (one beam generated by one laser diode). Since only one laser beam can be used, the speed of reading information on the optical disk, which is called the data transfer speed, is slow, and there is a marked difference in the speed as compared with the multiple head technology such as a magnetic disk. In addition, the problem with the single head is the same as the writing speed, which has been a cause of limiting the application fields of the optical disk device.
Therefore, it is necessary to provide a plurality of laser beams for the optical head in the optical disk device, and the following proposals have been made.

That is, a method of mounting a plurality of laser diodes on a single body of an optical head (laser array) has been proposed.

In addition, it has been proposed to dispose a plurality of optical heads at different angles in the circumferential direction of the optical disc.

(Problems to be Solved by the Invention) In the case of one optical head that generates only one beam, there is an inherent drawback that the speed of reading and writing information is slow as described above.

Further, in the laser array method, it is difficult to assemble and adjust, and there still remains a solution to the characteristic difference between individual laser diodes and the problem when one laser diode fails. Moreover, in many cases
Since the single optical system is shared, the laser beam cannot be controlled independently. Another problem remains that the laser array is difficult to manufacture and the price does not decrease.

In addition, the method of arranging a plurality of optical heads at different angles in the circumferential direction of the optical disk is not always available because of the window of the cassette when the optical disk is contained in the cassette case.

Therefore, it is an object of the present invention to provide a multi-stage optical head for an optical disk device, which can solve the above-mentioned conventional drawbacks and improve the data transfer rate of the optical disk device, thereby expanding its application field. In particular, even when the optical disk is stored in a cassette and the optical disk can be accessed only from the cassette window, the data writing and reading speeds are increased to solve the slow transfer speed, which is the biggest drawback of the optical disk devices to date. Also,
Another object of the present invention is to provide a multi-stage multi-optical head for an optical disk device, which can realize mass productivity and low price in manufacturing the structure of the optical head by utilizing conventional technology as much as possible. To do.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a multistage multi-optical head in which at least two, preferably three or four, optical heads can be inserted into a cassette window of an optical disk. Is adopted. As a result, compared with the conventional device using one optical head, a data transfer rate three to four times that of the conventional optical head can be obtained even if the optical disk cassette window is limited. Further, when there is no limitation on the cassette window, such multi-stage multi optical heads are arranged at different angles in the circumferential direction of the optical disc, for example, by arranging four of them.
Transfer rates of 12 to 16 times can be obtained.

(Embodiment) Next, a preferred embodiment of the multistage multi-optical head of the present invention will be described with reference to the drawings.

First, referring to FIGS. 1 to 6, FIGS. 1 to 6 are views showing a first embodiment of a multistage optical head according to the present invention. In particular, FIG. 1 is a magneto-optical disk cassette. And FIG. 3 is a perspective view of a multistage multi-optical head in which the linear motor is indicated by a dotted line, and FIGS. 2, 3, and 4 are plan views, front views, and side views of the multistage multi-optical head in which the linear motor is omitted. FIG. 5 and FIG. 6 are a plan view and a front view of a multistage multi-optical head including a linear motor, respectively.

In the first embodiment, an optical system unit in which optical system bodies are vertically stacked in multiple stages and fixed, an actuator unit in which actuators are juxtaposed and fixed, and a mirror portion which optically connects the optical system unit and the actuator unit,
Is integrally fixed to form a single movable unit. In this specification, the vertical direction means a direction perpendicular to the surface of a magneto-optical disk cassette placed horizontally.

In particular, as shown in FIGS. 1 to 4, the multistage multi-optical head 14 of the present invention comprises an optical system unit 16, a mirror section 24 and an actuator unit 32. Optical system unit 16
Is, for example, three optical system main bodies 18, 20, 22 which are vertically stacked and fixed. The main body of the optical system itself is a well-known one, and includes a laser diode, a detector, a condenser lens, a beam splitter, a 1/4 wavelength plate and the like.
And laser diodes of each optical system main body 18, 20, 22
18a, 20a, 22a and detectors 18b, 20b, 22b are attached to the side wall of the case of the optical system body so that their terminals are exposed to the outside (in particular, see FIG. 4).

A mirror section 24 is fixed to the optical system unit 16, and the mirror section 24 has mirrors 26, 28, 30. Mirror 2
Reference numerals 6, 28 and 30 denote the objective lenses 40 of the actuators, which will be described later, the laser beams from the optical system bodies 18, 20, and 22, respectively.
It is arranged so as to face 42 and 44.

Furthermore, the actuator unit 32
Is fixed, and the actuator unit 32 has actuators 34, 36, 38 which are fixed in parallel in the horizontal direction.

As described above, the multistage multi optical head 14 includes the optical system unit 1
6. The mirror unit 24 and the actuator unit 32 are configured as a movable unit integrally fixed.

As shown in FIGS. 5 and 6, a multistage multi optical head
14 is configured to be moved by any suitable means, such as linear motor 46. The linear motors 46 are arranged on both sides of the multi-stage multi optical head 14 and include a core (yoke) 48, and a coil 50 that is movable with respect to the core 48 and fixed to a side portion of the multi-stage multi optical head 14.

Next, the moving direction of the multi-stage multi-optical head will be described with reference to FIG. 1 in particular. The magneto-optical disk cassette 10 has a cassette window 12, and the actuator unit 32 extends from below to within this window 12. Approaching and actuator unit
The 32 actuators 34, 36, 38 are arranged so as to be moved in the radial direction of the magneto-optical disk cassette 10 by a linear motor 46. Therefore, since the area that was conventionally covered by one actuator can be covered by three actuators, it is possible to obtain a read and write speed about three times that of the prior art.

Next, a second embodiment of the multistage optical head according to the present invention will be described with reference to FIGS. FIG. 7 is a perspective view of the multistage multi optical head of the second embodiment, and FIGS. 8, 9 and 10 are a plan view, a front view and a side view of the multistage multi optical head, respectively.

The second embodiment is different from the first embodiment in that the optical system unit 16 is separated from the actuator unit 32 and the mirror section 24 and fixed to the frame of the optical disk device, and other configurations are substantially the same. Is the same as

That is, as shown in FIGS. 7 to 9, the optical system unit 16 is separated from the mirror section 24 and is fixed to a frame (not shown) of the optical disk device, and the actuator unit 32 and the mirror section 24. Are moved by the linear motor 46 in the window 12 of the magneto-optical disk cassette 10 in the radial direction. The optical axis of the laser beam of the laser diode in each of the optical system bodies 18, 20, 22 is parallel to the moving direction as indicated by the chain line ("A", "B", "C"). The laser beam is a mirror of the mirror unit 24
After being reflected by 26, 28 and 30, they are directed to the objective lenses 40, 42 and 44 of each actuator 34, 36 and 38.

The second embodiment requires adjustment of the optical path as compared with the first embodiment, but the load on the linear motor is reduced and the linear motor can be downsized.

Next, a third embodiment of the multistage optical head according to the present invention will be described with reference to FIGS. 11 to 13. FIG. 11 is a perspective view of a multistage optical head according to the third embodiment, and FIGS. 12 and 13 are a plan view and a side view of the multistage optical head, respectively.

The optical system bodies are arranged horizontally in a flat manner, and are suitable when the optical system bodies are vertically stacked and there is not enough space in the vertical direction. In particular, as shown in FIG. 11, each optical system main body 18, 20, 22 is arranged so as to surround the mirror portion 24 from three sides,
The light beam from each optical system body is directed to the objective lenses 40, 42, 44 of the actuators 34, 36, 38 via the mirror section 24.

The optical system unit 16, the mirror unit 24, and the actuator unit 32 are integrally fixed to form a movable unit as in the first embodiment, and are linearly moved by the linear motor 46 in the radial direction with respect to the magneto-optical disk cassette 10. Moving.

(Effects of the Invention) As described in detail above, when the present invention is applied when an optical disc is housed in a cassette, (1) three conventional optical heads are used despite the limitation of the cassette window frame. Therefore, it is possible to improve the data transfer rate, which is a drawback of the optical disk device, by 3 to 4 times. (2) Since the optical system main body and the actuator are used as individual units, the conventional optical head manufacturing method can be used, the assembly and adjustment can be simplified, and the cost can be reduced. (3) By designing the portion connecting the optical system unit and the actuator unit, the layout of the unit can be changed to a position suitable for the intended use.

When it is applied to an optical disc that does not have a cassette, (1) it is possible to arrange the discs at an angle offset in the circumferential direction, and it is possible to arrange three to four times the number of optical heads in the same occupied area. Become.

[Brief description of drawings]

FIG. 1 is a perspective view of a multi-stage multi optical head in which a magneto-optical disk cassette and a linear motor are indicated by dotted lines. 2, 3, and 4 are a plan view, a front view, and a side view, respectively, of a multi-stage multi-optical head in which the linear motor is omitted. FIG. 5 and FIG. 6 are a plan view and a front view of a multistage multi optical head including a linear motor, respectively. FIG. 7 is a perspective view of the multistage multi optical head of the second embodiment. FIG. 8, FIG. 9 and FIG. 10 are a plan view, a front view and a side view of a multi-stage multi optical head, respectively. FIG. 11 is a perspective view of the multistage multi optical head of the third embodiment. FIG. 12 and FIG. 13 are a plan view and a side view of a multistage multi optical head, respectively. 10 …… magneto-optical disc cassette, 12 …… magneto-optical disc cassette window, 14 …… multi-stage multi-optical head, 16 …… optical system unit, 18, 20, 22 …… optical system body, 24 …… mirror section, 26, 28, 30 …… Mirror, 32 …… Actuator unit, 34,36,38 …… Actuator, 46 …… Linear motor.

Claims (6)

[Claims] 1. A multi-stage multi-optical head for an optical disc apparatus, wherein an optical system unit composed of a plurality of optical system main bodies, which are vertically stacked and fixed, each having a light source, and juxtaposed in the radial direction of a magneto-optical disc cassette. An actuator unit composed of a plurality of fixed actuators, and a mirror section having a plurality of mirrors connecting the optical system unit and the actuator unit and directing a laser beam from each optical system body of the optical system unit to each actuator of the actuator unit. A means for moving a movable unit composed of the optical system unit, an actuator unit and a mirror section in the radial direction of the magneto-optical disk cassette, and a multi-stage multi-optical head for an optical disk device. 2. The multi-stage multi optical head for an optical disc device according to claim 1, wherein the moving means is a linear motor. 3. A multi-stage multi-optical head for an optical disk device, wherein an optical system unit composed of a plurality of optical system main bodies which are vertically stacked and fixed and each have a light source, and which are juxtaposed in the radial direction of a magneto-optical disk cassette. An actuator unit including a plurality of fixed actuators; a mirror unit having a plurality of mirrors connected to the actuator unit and for directing a laser beam from each optical system body of the optical system unit to each actuator of the actuator unit; And a means for moving a movable unit composed of a mirror portion in the radial direction of the magneto-optical disk cassette, and a multi-stage multi-optical head for an optical disk device. 4. The multi-stage multi optical head for an optical disc device according to claim 3, wherein the moving means is a linear motor. 5. In a multi-stage optical head for an optical disk device, an optical system unit which is arranged and fixed in a horizontal direction and comprises a plurality of optical system main bodies each having a light source, and a magneto-optical disk cassette are juxtaposed in the radial direction. Actuator unit composed of a plurality of fixed actuators, a mirror section having a plurality of mirrors for directing a laser beam from each optical system body of the optical system unit to each actuator of the actuator unit, the optical system unit, the actuator unit, and A multi-stage multi-optical head for an optical disk device, comprising: a means for moving a movable unit composed of a mirror section in a radial direction of a magneto-optical disk cassette. 6. The multi-stage multi optical head for an optical disc apparatus according to claim 5, wherein the moving means is a linear motor.