JPH02236840A - Multistage multi-optical head for optical disk - Google Patents

Abstract

PURPOSE:To adopt a multistage multi-optical head for a magneto-optical disk cassette, and to improve transfer speed by inserting >= two optical heads to an optical disk window. CONSTITUTION:A multistage multi-optical head 14 is composed as a movable unit, which is obtained by integrally fixing an optical system unit 16, a mirror part 24, and an actuator unit 32. The unit 32 approaches the window in the range of a cassette window 12 of an optical disk cassette 10, and moves respective actuators 34, 36 and 38 by a linear motor 46. Thus regardless of the restriction of a cassette window frame, the plural optical heads can be used, and the data transfer speed is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-stage multi-optical head for an optical disc device. (Prior Art) Conventionally, optical disk devices have generally been equipped with one optical head (one beam generated by one laser diode). Because only one laser beam could be used, the speed at which information on the optical disk could be read, known as the data transfer rate, was slow, and there was a significant difference in speed compared to multi-head technology such as magnetic disks. In addition, the problems caused by a single head also affected the writing speed, which limited the field of application of optical disk devices. Therefore, it is necessary to provide multiple laser beams for the optical head of the optical disk device, and the following proposals have been made. In other words, a method has been proposed in which multiple laser diodes are mounted on a single body of an optical head (laser array). Another proposal has been made to arrange multiple optical heads at different angles in the circumferential direction of the optical disk. (Problems to be Solved by the Invention) A single optical head that generates only one beam has an inherent drawback of slow information reading and writing speeds, as described above. In addition, the laser array method is difficult to assemble and adjust, and problems such as differences in characteristics of individual laser diodes and problems when one laser diode breaks down still remain to be solved. Furthermore, in many cases
Since they share a single optical system, it was not possible to control the laser beams independently. Another problem remains that laser arrays are difficult to manufacture and prices are not going down. Furthermore, the method of arranging multiple optical heads at different angles in the circumferential direction of the optical disk was not always usable when the optical disk was in a cassette case because of the cassette window. Accordingly, an object of the present invention is to provide a multi-stage multi-optical head for an optical disk device that can overcome the above-mentioned conventional drawbacks, improve the data transfer speed of the optical disk device, and expand its field of application. In particular, the objective is to speed up data writing and reading speeds even when the optical disc is stored in a cassette and can only be accessed through the cassette window, thereby solving the slow transfer speed that has been the biggest drawback of conventional optical disc devices. Another object of the present invention is to improve the structure of the optical head by
The object of the present invention is to provide a multi-stage multi-optical head for an optical disk device, which can be manufactured in mass production and at low cost by utilizing conventional technology as much as possible. (Means for Solving the Problems) In order to achieve the above object, the present invention provides a multi-stage multi-optical head that allows at least two, preferably three or four, optical heads to be inserted into the cassette window of an optical disc. was adopted. As a result, compared to a conventional device using a single optical head, it is possible to obtain a data transfer rate three to four times faster than that of a conventional device using a single optical head, even with the limitations of the optical disk cassette window. Furthermore, if there is no restriction on the cassette window, a transfer speed of 12 to 16 times can be obtained by arranging, for example, four such multi-stage multi-optical heads at different angles in the circumferential direction of the optical disk. ．． (Embodiment) Next, a preferred embodiment of the multi-stage 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 diagrams showing a first embodiment of the multi-stage multi-optical head of the present invention, and in particular,
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 shown by dotted lines, and FIGS. 2, 3, and 4 are a multi-stage multi-optical head in which the linear motor is omitted, respectively. 5 and 6 are a plan view and a front view, respectively, of a multi-stage multi-optical head including a linear motor. This first embodiment includes an optical system unit in which optical system bodies are vertically stacked and fixed in multiple stages, an actuator unit in which actuators are arranged and fixed in parallel, a mirror section that optically connects the optical system unit and the actuator unit, are fixed together to form a single movable unit. In this specification, the vertical direction refers to a direction perpendicular to the surface of a magneto-optical disk cassette placed horizontally. In particular, as shown in FIGS. 1 to 4, the multi-stage multi-optical head 14 of the present invention includes an optical system unit 16, a mirror section 24,
and an actuator unit 32. The optical system unit 16 includes, for example, three optical system bodies 18, 20, 22.
are stacked vertically and fixed. The optical system itself is well known and includes a laser diode, a detector, a condenser lens, a beam splitter, a 1/4 wavelength plate, etc. And each optical system main body 18, 20, 2
The two laser diodes 18a, 20a, 22a and the 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 (see especially FIG. 4). A mirror section 24 is fixed to the optical system unit 16, and the mirror section 24 includes mirrors 26, 28, and 30. The mirrors 26, 28, and 30 are the optical system main body 18,
The laser beams from the actuators 20 and 22 are arranged to be directed to objective lenses 40, 42, and 44 of actuators, which will be described later. Further, an actuator unit 32 is fixed to the mirror portion 24, and the actuator unit 32 has actuators 34, 36, and 38 fixed in parallel with each other in the horizontal direction. In this way, the multi-stage multi-optical head 14 is configured as a movable unit in which the optical system unit 16, the mirror section 24, and the actuator unit 32 are fixed together. As shown in FIGS. 5 and 6, the multi-stage multi-optical head 14 is configured to be moved by any suitable means, such as a near motor 46. linear motor 4
Reference numeral 6 denotes a core (yoke) 48 which is arranged on both sides of the multi-stage multi-optical head 14, and a coil 50 which is movable with respect to the core 48 and fixed to the side of the multi-stage multi-optical head 14.
It consists of. Next, the direction of movement of the multi-stage multi-optical head will be explained with particular reference to FIG. The actuators 34, 36, and 38 of the actuator unit 32 are arranged to be moved in the radial direction of the magneto-optical disk cassette 10 by a linear motor 46. Therefore, the area that has traditionally been covered by one actuator is now three.
Since it can be covered with 3 actuators, it is approximately 3 times smaller than before.
You can get double the read and write speed. Next, a second embodiment of the multi-stage multi-optical head of the present invention will be described with reference to FIGS. 7 to 10. Figure 7 is the second
FIG. 8 is a perspective view of the multi-stage multi-optical head of the embodiment;
9 and 10 are a plan view, a front view, and a side view, respectively, of the multi-stage multi-optical head.

The second embodiment differs 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 disc device, and the 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 the frame (not shown) of the optical disc device, and is connected to the actuator unit 32 and the mirror section 24. The window 12 of the magneto-optical disk cassette 10 is moved by the linear motor 46.
can be moved radially within. And each optical system body 1
The optical axes of the laser beams of the laser diodes 8, 20, and 22 are parallel to the moving direction as shown by the dashed lines ("A", "B", "C"), and therefore each laser beam is directed to the mirror section. After reflection on the mirrors 26, 28, 30 of 24, the objective lens 4 of each actuator 34, 36, 38
Directed to 0, 42, 44. Although the second embodiment requires adjustment of the optical path compared to the first embodiment, the load on the linear motor is reduced and the linear motor can be made smaller. Next, from Figure 11 to Figure 1
A third embodiment of the multi-stage multi-optical head of the present invention will be described with reference to FIG. FIG. 11 is a perspective view of the multi-stage multi-optical head of the third embodiment, and FIGS. 12 and 13 are a plan view and a side view of the multi-stage multi-optical head, respectively. The optical system bodies are arranged flat in the horizontal direction, and are suitable when there is not enough space in the vertical direction when stacking the optical system bodies vertically. In particular, as shown in FIG. 11, each optical system main body 18, 20, 22 is arranged so as to surround a mirror section 24 from three sides, and the light beam from each optical system main body passes through the mirror section 24. is directed toward the objective lens 40, 42, 44 of each actuator 34, 36, 38. The optical system unit 16, the mirror section 24, and the actuator unit 32 are integrally fixed to form a movable unit as in the first embodiment, and are moved in the radial direction relative to the magneto-optical disk cassette 10 by a linear motor 46. Moving. (
Effects of the Invention) As explained in detail above, when the present invention is applied to a case where an optical disc is housed in a cassette, it is possible to reduce the number of conventional optical heads from three to three despite the limitations of the cassette window frame. Since four discs can be used, the data transfer speed, which is a drawback of optical disc devices, can be improved three to four times. (2) Since the optical system body and actuator are made into individual units, conventional optical head manufacturing methods can be used, assembly and adjustment can be simplified, and costs can be reduced.
(3) By designing the part that connects the optical system unit and the actuator unit, the unit layout can be changed to a position that suits the application. When applied to optical discs that do not have cassettes, (1) they can be arranged at different angles in the circumferential direction of the disc, making it possible to arrange three to four times as many optical heads in the same occupied area. becomes.

[Brief explanation of drawings]

Figure 1 is a perspective view of a multi-stage multi-optical head, with the magneto-optical disk cassette and linear motor indicated by dotted lines. 2, 3, and 4 are a plan view, a front view, and a side view of a multi-stage multi-optical head, respectively, with the linear motor omitted. Figures 5 and 6 are a plan view and a front view of the multi-stage multi-optical head including the linear motor, respectively. FIG. 7 is a perspective view of the multi-stage multi-optical head of the second embodiment. 8, 9, and 10 are a plan view, a front view, and a side view, respectively, of the multi-stage multi-optical head. FIG. 11 is a perspective view of the multi-stage multi-optical head of the third embodiment. Figures 12 and 13 are a plan view and a side view of the multi-stage multi-optical head, respectively. DESCRIPTION OF SYMBOLS 10... Magneto-optical disk cassette, 12... Window of magneto-optical disk cassette, 14... Multi-stage multi-optical head, 16... Optical system unit, 18, 20, 22... Optical system main body, 24 ...Mirror part, 26, 28, 30... Mirror 32... Actuator unit, 34, 36, 38... Actuator, 46... Linear motor. U5-1 267- nto+rll-1- d 1>mu

Claims (6)

[Claims] (1) In a multi-stage multi-optical head for an optical disk device, an optical system unit consisting of a plurality of optical system bodies stacked vertically and fixed, and a plurality of actuators arranged side by side and fixed in the radial direction of a magneto-optical disk cassette. an actuator unit consisting of; a mirror section having a plurality of mirrors that connects the optical system unit and the actuator unit and directs a laser beam from each optical system main body of the optical system unit to each actuator of the actuator unit; the optical system unit; 1. A multi-stage multi-optical head for an optical disc device, comprising: means for moving a movable unit composed of an actuator unit and a mirror section in a radial direction of a magneto-optical disc cassette. (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) In a multi-stage multi-optical head for an optical disk device, an optical system unit consisting of a plurality of optical system bodies stacked vertically and fixed, and a plurality of actuators arranged and fixed in parallel in the radial direction of a magneto-optical disk cassette. an actuator unit consisting of; a mirror section connected to the actuator unit and having a plurality of mirrors that direct the laser beam from each optical system body of the optical system unit to each actuator of the actuator unit; and the actuator unit and the mirror section. 1. A multi-stage multi-optical head for an optical disc device, comprising: means for moving a movable unit in a radial direction of a magneto-optical disc cassette. (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 multi-optical head for an optical disk device, an optical system unit consisting of a plurality of optical system bodies arranged and fixed in the horizontal direction, and a plurality of actuators arranged and fixed in the radial direction of a magneto-optical disk cassette. an actuator unit consisting of; a mirror section having a plurality of mirrors that direct laser beams from each optical system main body of the optical system unit to each actuator of the actuator unit; A multi-stage multi-optical head for an optical disc device, comprising: means for moving the unit in the radial direction of a magneto-optical disc cassette. (6) The multi-stage multi-optical head for an optical disc device according to claim 5, wherein the moving means is a linear motor.