JPH0675289B2 - Optical recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus of an apparatus for optically recording / reproducing information.

Conventional Technology It is said that the present age is the information age, and the technological development of high-density and large-capacity memory, which is the core of it, is being actively conducted. In addition to the above-mentioned high density and large capacity, the ability required for the memory includes high reliability, high speed access, etc., and the optical disk memory is most attracted to satisfy these requirements. The present invention relates to high speed access means in an optical recording / reproducing apparatus.

The optical recording / reproducing apparatus is composed of optical elements such as a semiconductor laser, a collimator lens, a half mirror, etc., and means for detecting a focus error signal on a disk-shaped recording medium and a means for detecting a tracking error signal on the disk-shaped recording medium. And an objective lens for forming a light spot on a disk-shaped recording medium such as a magneto-optical disk, and an optical system including information detecting means for detecting information on the disk-shaped recording medium. It has a mechanism for driving in a focus direction F perpendicular to the medium surface and a tracking direction T in the radial direction parallel to the recording medium surface, and optically records and reproduces information on the disc-shaped recording medium. To do.

A conventional optical recording / reproducing apparatus of this type has a structure as shown in FIG.

As shown in FIG. 4A, the rotary member 3 has a hollow rotary shaft 22.
Are fixed to the housing 19 via bearings 15a and 15b. Two parallel leaf springs 4a and 4b are provided at one end of the rotating member 3.
Lens holder 5 with objective lens 6 attached via
Is installed. The light beam 23 emitted from the fixed optical system 1 which is fixed below the housing 19 and separated therefrom passes through the rotation center of the rotation shaft 22 and is attached to the rotating member 3.
It is configured such that it is totally reflected by both end faces 24a, 24b of 21 and enters the objective lens 6.

Driving in the tracking direction T is performed integrally with the rotating member 3,
An electric motor in which a tracking direction driving magnet 12 fixed to a rotating yoke 20 that rotates around a rotating shaft 22 and a tracking drive coil 11 integrally attached to a magnetic yoke 18 fixed to a housing 19 are arranged. It is obtained by rotating about the rotating shaft 22 by the mold converter. As shown in FIG. 4B, for driving in the focus direction F, the focus driving coil 9 attached to the lens holder 5 is arranged in the space 17 of the magnetic circuit composed of the focus driving magnet 10 and the magnetic yokes 16a and 16b. By the electrokinetic converter described above, the lens holder 5 having the objective lens attached thereto is translated by two parallel leaf springs 4a and 4b.

Here, the focus drive coil 9 and the air gap 17 are formed in an arc shape centered on the rotation axis in the tracking direction T.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An optical recording / reproducing apparatus records / reproduces information at an arbitrary position on a recording medium, and thus shortening the access time becomes a very important issue.

The optical recording / reproducing apparatus having the structure shown in FIG. 4 includes optical elements such as a semiconductor laser, a collimator lens, and a half mirror, a focus error signal detecting means, a tracking error signal detecting means, etc. in order to shorten the access time. By separating the fixed optical system 1 composed of the above from the rotating member 3, the weight of the movable portion is reduced and the access time is shortened. However, there is a limit to the reduction of the weight of the movable part and the increase of the driving force for driving the movable part, and it has been difficult to achieve an access time comparable to that of a magnetic disk.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an optical recording / reproducing apparatus capable of significantly shortening the access time.

Means for Solving the Problems In order to achieve the above object, an optical recording / reproducing apparatus according to the present invention includes a fixed optical system, a movable member, and a rotation of a light reflecting surface provided near a rotation center of a rotating member. A galvanometer mirror having an angle detecting means, a driving means which is provided at one end of the rotating member, and which drives a lens holder having a plurality of objective lenses substantially in the radial direction of the disk-shaped recording medium in the optical axis direction of the objective lens, It is composed of the same number of mirrors as the objective lenses, which is fixed to one end of the moving member, and reflects the light flux from the galvano mirror toward the objective lens, and the light flux position detecting means of the same number as the objective lenses.

Effect According to the present invention, when accessing an arbitrary position in the recording area of the disk-shaped recording medium with the above-described configuration, the direction of the light flux is changed by the galvano mirror toward the nearest lens, so that the moving distance of the rotating member is reduced. Very few. Therefore, the access time can be greatly shortened.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.
1A and 1B are views showing a schematic configuration of an optical recording / reproducing apparatus in an embodiment of the present invention.

In FIG. 1A, 1 is a fixed optical system, 2 is a galvanometer mirror, 3 is a rotating member, 4 is a leaf spring, 5 is a lens holder,
6a, 6b and 6c are objective lenses, 7 is a disk which is a disk-shaped recording medium, 8 is a mirror, 30 is a rotation angle detection sensor, 31a, 31b,
31c is a light beam position detection sensor. Lens holder 5
Is connected to the rotating member 3 via a leaf spring 4. The light reflecting surface of the galvanometer mirror 2 and the rotating member 3 rotate about an axis X perpendicular to the paper surface. FIG. 1B is the same as FIG. 1A.
8 is a view showing a cross section taken along line AA, 8 is a mirror, 9 is a focus drive coil, 10 is a focus drive magnet, 11 is an access drive coil, 12 is an access drive magnet, 13 is a base, 14 is a shaft, and 15 is It is a bearing. The mirror 8 is fixed to one end of the rotating member 3 so as to reflect the light flux from the galvanometer mirror 2 toward the objective lenses 6a, 6b, 6c.
In the present embodiment, the number of mirrors 8 is the same as the number of objective lenses, but this may be replaced with a single mirror having the same number of light reflecting surfaces as the number of objective lenses.

The operation of the embodiment of the optical recording / reproducing apparatus configured as described above will be described below. Figure 1A
Further, in FIG. 1B, the light is emitted from the fixed optical system 1 which is composed of optical elements such as a semiconductor laser, a collimator lens, and a photodetector, and has detection means for a focus error signal, a tracking error signal, an information signal and the like. The parallel light flux is reflected by the galvanometer mirror 2, and after being reflected by the mirror 8, the objective lens
It is incident on any of 6a, 6b, and 6c. In the case of FIG. 1A, a light spot is formed on the disk 7 by the objective lens 6b.

One side of the access drive coil 11 is fixed to the rotating member 3,
A driving force for rotating the rotating member 3 is generated by a combination with the access driving magnet 12 fixed to the base 13. The focus drive coil 9 is wound around the lens holder 5 and fixed to the base 13 for focus drive.
By combining with 10, the lens holder 5 can be used as the objective lens 6
It drives in the optical axis directions of a, 6b, and 6c (focus direction) to perform focus control.

FIG. 2 is a diagram showing only the main part of the present invention in order to explain the operation of the present invention. FIG. 2A shows a case where the innermost circumference of the recording area of the disk 7 is accessed. In this case, the galvanometer mirror 2 is
The light flux is moved to the position where the objective lens 6a will move in the shortest time while detecting the rotation angle of the light reflecting surface. At the same time, the rotating member 3 rotates so that the objective lens 6a comes to the innermost circumference of the disk 7. Positioning of the light beam and the objective lens 6a is performed by correcting and rotating the galvanometer mirror 2 based on the signal detected by the light beam position detection sensor 31a.

FIG. 2B shows a case where the outermost circumference of the recording area of the disk 7 is accessed. Also in this case, it is possible to access in the same manner as in FIG. 2A.

As the rotation angle detection sensor 30 that detects the rotation angle of the galvano mirror 2, an optical type sensor or another general sensor may be used. Similarly, various methods can be used for the light beam position detection sensors 31a, 31b, 31c, but in the present embodiment, the method shown in FIG. 3 is adopted.

FIG. 3 is a diagram showing the detection principle of the light beam position detection sensor 31a, wherein 32 is a photodetector which constitutes the light beam position detection sensor 31a, 33 is a differential amplifier, and 34 is a light beam. Objective lens
Since the light beam diameter of the light beam 34 incident on the 6a is larger than the diameter of the objective lens 6a, the lens holder 5 or the rotating member 3 is positioned at the position in the light beam sweeping direction by the galvano mirror 2 outside the diameter of the objective lens 6a. It is possible to detect the relative displacement between the light beam 34 and the objective lens 6a by receiving the light beam 34 with the two photodetectors 32 provided and taking the differential output with the differential amplifier 33. is there. By feeding back the light beam position error signal output from the differential amplifier 33 to the galvano mirror 2, the galvano mirror 2 can be finely rotated and the light beam 34 can be quickly matched with the objective lens 6a. In FIG. 3, the objective lens 6a and the light flux position detection sensor 31a are described, but the same applies to other objective lenses and the light flux position detection sensor.

In order to shorten the access time, the weight of the movable part has been reduced and the driving force has been increased in the past, but these methods have limitations. The present invention aims to shorten the access time by shortening the access distance itself. When three objective lenses are used as in the present embodiment, the recording area handled by each objective lens is about 1/3 of that of the conventional example having one objective lens.
Since the amount of rotation of the rotating member 3 also becomes about 1/3 accordingly,
It is possible to access any position on the disk 7 at high speed. Further, by providing the galvanometer mirror with the rotation angle detection sensor and the light beam position detection sensor in the vicinity of the objective lens, more accurate and high-speed access operation can be performed.

In this embodiment, three objective lenses are used, but any number of objective lenses may be used.

Further, although the galvano mirror 2 is illustrated as being fixed to the rotating member 3 in the present embodiment, it may be fixed to the base 13 if necessary.

EFFECTS OF THE INVENTION The present invention provides, as an access means of an optical recording / reproducing apparatus,
Recording on a disk-shaped recording medium by using a fixed optical system, a galvano mirror having a rotation angle detection sensor, a rotating member having a plurality of mirrors and a plurality of objective lenses, and a plurality of light beam position detection sensors It is possible to realize an excellent optical recording / reproducing apparatus capable of accessing any position in the area at high speed and achieving a significant reduction in access time, which was difficult with the conventional method.

[Brief description of drawings]

1A and 1B are schematic diagrams of an optical recording / reproducing apparatus according to an embodiment of the present invention, and FIGS. 2A, 2B and 3 are schematic diagrams for explaining the operation thereof. 4A and 4B are schematic views of a conventional optical recording / reproducing apparatus. 1 ... Fixed optical system, 2 ... Galvano mirror, 3 ... Rotating member, 4 ... Leaf spring, 5 ... Lens holder, 6a, 6b, 6c
…… Objective lens, 7 …… Disk, 8 …… Mirror, 9 ・ ・ ・
Focus drive coil, 10 Focus drive magnet, 11 Access drive coil, 12 Access drive magnet, 13 Base, 14 Shaft, 15 Bearing,
30 …… Rotation angle detection sensor, 31a, 31b, 31c …… Light flux position detection sensor, 32 …… Photo detector, 33 …… Differential amplifier, 34
… Luminous flux.

Claims (1)

[Claims] 1. A device comprising an optical element such as a semiconductor laser, a collimator lens, and a half mirror, for detecting a focus error signal on a disk-shaped recording medium, and means for detecting a tracking error signal on the disk-shaped recording medium, A fixed optical system including means for detecting an information signal on the disc-shaped recording medium, and a rotation about an axis substantially parallel to an optical axis direction perpendicular to the recording medium surface of the disc-shaped recording medium. A galvanometer mirror having a movable mechanism for reflecting the light flux from the fixed optical system in an arbitrary direction within a plane substantially parallel to the recording medium surface of the disk-shaped recording medium; A rotating member provided with a mechanism for driving in a direction substantially parallel to the recording medium surface of the disk-shaped recording medium about a parallel axis, and fixed to the rotating member; Previous A plurality of objective lenses for forming a minute light spot on the disc-shaped recording medium, and a mechanism for driving a lens holder arranged in a substantially straight line in a substantially radial direction of the disc-shaped recording medium in the optical axis direction. Objective lens driving means, mirrors fixed to the rotating member, the number of which is equal to the number of the objective lenses for allowing the light flux emitted from the fixed optical system to enter substantially parallel to the optical axis of the objective lens, and the rotation. An optical recording / reproducing apparatus comprising: a member, or the objective lens fixed to the lens holder, for detecting the position of a light beam from the galvanometer mirror, and the same number of light beam position detecting means as the mirrors.