JPH01196735A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To quickly access an arbitrary position on the recording area of a disk-shaped recording medium by using a fixed optical system, a galvano mirror, plural mirrors, a turning member having an objective lens, and plural luminous flux position detecting sensors. CONSTITUTION:Parallel rays of the luminous flux from a fixed optical system 1 which consists of optical elements such as a semiconductor laser and a photodetector and has detecting mean of a focus error signal, a tracking error signal, etc., are reflected on a galvano mirror 2 and mirrors 8 and are made incident on objective lenses 6a-6c to form a light spot on a disk 7. At the time of accessing an arbitrary position on the recording area of the disk 7, a turning member 3 is turned toward nearest one of lenses 6a-6c together with the galvano mirror 2 based on signals of a rotation angle detecting sensor 30 and a luminous flux position detecting sensor 31. Consequently, the extent of movement of the member 3 is very short and the access time is considerably shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical recording and reproducing device for optically recording and reproducing information.

Conventional Technology The modern era is said to be the information age, and the technology development of high-density, large-capacity memory, which forms the core of this era, is actively underway. In addition to the above-mentioned high density and large capacity, the capabilities required of memory include high reliability and high-speed access, and optical disk memory is attracting the most attention as a device that satisfies these requirements. The present invention relates to high-speed access means in an optical recording/reproducing device.

The optical recording/reproducing device is composed of optical elements such as a semiconductor laser, a collimating lens, and a half mirror, and includes means 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. and an information detection means for detecting information on the disc-shaped recording medium, and an objective lens for forming a light spot on the disc-shaped recording medium such as a magneto-optical disk. It has a mechanism that drives in a focus direction F perpendicular to the medium surface and a tracking direction T parallel to the recording medium surface, and optically records and reproduces information on a disk-shaped recording medium. conduct.

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

As shown in FIG. 4, the rotating member 3 has a hollow rotating shaft 2.
2 is fixed to the housing 19 via bearings 1sa and 1sb. A lens holder 6 to which an objective lens 6 is attached is installed at one end of the rotating member 3 via two parallel leaf springs 4a*4b. The light beam 23 emitted from the fixed optical system 1 fixed separately below the housing 19 passes through the center of rotation of the rotating shaft 22 and reaches both end surfaces 24a and 2 of the prism 21 attached to the rotating member 3.
It is configured so that it is totally reflected by the beam 4b and enters the objective lens 6.

The driving in the tracking direction T is performed integrally with the rotating member 3,
A motor with a tracking direction drive magnet 12 fixed to a rotation yoke 2o rotating around a rotation axis 22 and a tracking drive coil 11 integrally attached to a magnetic yoke 18 fixed to a housing 19. This is obtained by rotating the electric type converter about the rotation axis 22. As shown in FIG. 4B, driving in the focus direction F is performed using a focus drive magnet 1Q and a magnetic yoke 162.
An electrodynamic transducer in which a focus drive coil 9 attached to a lens holder 6 is arranged in a gap 17 of a magnetic circuit consisting of a magnetic circuit L and 16b causes two parallel leaf springs 4
This is obtained by the translational movement of the lens holder 5 to which the objective lens is attached via a + 4 b.

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

Problems to be Solved by the Invention Since optical recording and reproducing devices record and reproduce information at arbitrary positions on a recording medium, shortening access time has become a very important issue.

The optical recording/reproducing device having the configuration shown in FIG. 4 uses optical elements such as a semiconductor laser, a collimating lens, and a half mirror, as well as focus error signal detection means, tracking error signal detection means, etc. in order to shorten access time. By separating the fixed optical system 1 consisting of the rotating member 3 from the rotating member 3, the weight of the movable part is reduced and the access time is shortened. However, there are limits to reducing the M amount of the movable part and increasing 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-mentioned problems, and an object of the present invention is to provide an optical recording/reproducing device that can significantly shorten access time.

Means for Solving the Problems In order to achieve the above object, the optical recording/reproducing device of the present invention includes a fixed optical system, a rotating member, and a light reflecting surface provided near the center of rotation of the rotating member. a galvanomimirror having a rotation angle detection means; a driving means for driving a lens holder provided at one end of the rotating member and having a plurality of objective lenses in a substantially radial direction of a disc-shaped recording medium in the optical axis direction of the objective lens; It is comprised of the same number of mirrors as the objective lens, which are fixed to one end of the rotating member, and which reflect the light flux from the galvanometer mirror in the direction of the objective lens, and the same number of light flux position detection means as the objective lens.

Effects According to the present invention, when accessing any position in the recording area of a disc-shaped recording medium, the direction of the light flux is changed by the galvanomirror toward the nearest lens, so that the moving distance of the rotating member is Very little amount is required. Therefore, it is possible to significantly shorten access time.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 and FIG. 1B are diagrams showing a schematic configuration of an optical recording/reproducing apparatus in an embodiment of the present invention.

In Figure 1, 1 is a fixed optical system, 2 is a galvano mirror, 13 is a rotating member, 4 is a leaf spring, 6 is a lens holder,
sa, eb, and ac are objective lenses; 7 is a disc that is a disc-shaped recording medium; 8 is a mirror; 3o is a rotation angle detection sensor; 31&, 31b.

31C is a light flux position detection sensor. The 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 around an axis X perpendicular to the plane of the drawing. FIG. 1B is a cross-sectional view taken along the line A-A of the person in FIG.
11 is an access drive coil, 12 is an access drive magnet, 13 is a base, 14 is a shaft, and 16 is a bearing. The mirror 8 is fixed to one end of the rotating member 3 so as to reflect the light beam from the galvanometer mirror 2 toward the objective lenses 6a, sb, and 6c. In this embodiment, the number of mirrors 8 is the same as that of the objective lens, but this may be replaced by a single mirror having the same number of light reflecting surfaces as the objective lens.

The operation of an embodiment of the optical recording/reproducing apparatus configured as described above will be explained below. In FIG. 1 and FIG. 1B, a fixed optical system 1 is composed of optical elements such as a semiconductor laser, a collimating lens, and a photodetector, and has detection means such as a focus error signal, a tracking error signal, and an information signal. The parallel light flux emitted from the mirror 2 is reflected by the galvanometer mirror 2, and after being reflected by the mirror 8, it enters one of the objective lenses sa, eb, and ac. In the case of a person in FIG. 1, a light spot is formed on the deinuk 7 by the objective lens 6b.

The access drive coil 11 has one side fixed to the rotating member 3, and in combination with the access driving magnet 12 fixed to the base 13, generates a driving force for rotating the rotating member 3. Focus drive coil 9 is attached to lens holder 6
In combination with the focus drive magnet 1° fixed to the base 13, the lens holder 5 is driven in the optical axis direction (focus direction) of the objective lens 62Lr6b+ac to perform focus control. .

FIG. 2 is a diagram showing only the main parts of the present invention in order to explain the invention in detail. FIG. 2 shows a case where a person accesses the innermost circumference of the recording area of the disk 7. In this case, the galvanometer mirror 2 moves the light beam to the position where the objective lens e& will be moved in the shortest possible time while detecting the rotation angle of the light reflecting surface using the rotation angle detection sensor 3o.

At the same time, the rotating member 3 rotates so that the objective lens 6a comes to the innermost circumference of the disk 7. The alignment between the light beam and the objective lens 6a is performed by correctively rotating the galvano mirror 2 based on the signal detected by the light beam position detection sensor 31B.

FIG. 2B shows a case where the outermost circumference of the recording area of the disk 7 is accessed. In this case as well, it is possible to access the user using the same method as in Figure 2.

The rotation angle detection sensor 3o that detects the rotation angle of the galvanomirror 2 may be an optical or other general sensor. In addition, the light flux position detection sensors 31a, 31b, 3
Similarly, various methods can be used for 1c, but in this embodiment, the method shown in FIG. 3 was adopted.

Is Fig. 3 the luminous flux position detection sensor 31? It is a diagram showing the detection principle of L, in which 32 is a photodetector constituting a light flux position detection sensor 311L, 33 is a differential amplifier, and 34 is a light flux. Since the beam diameter of the light beam 34 incident on the objective lens 61L is larger than the aperture of the objective lens 6a, the light beam 34 entering the objective lens 61L is
The light beam 34 is received by two photodetectors 32 each provided on the lens holder 5 or the rotating member 3 at a position in the direction of the light beam sweep by the galvanometer mirror 2 outside the aperture a,
By obtaining a differential output from the differential amplifier 33, it is possible to detect a relative positional shift between the light beam 34 and the objective lens 62L. By feeding back the beam position error signal, which is the output of the differential amplifier 33, to the galvano mirror 2, it is possible to slightly rotate the galvano mirror 2 and quickly align the beam 34 with the objective lens 6a. In FIG. 3, the objective lens 6a and the beam position detection sensor 31& have been described, but the same applies to other objective lenses and beam position detection sensors.

Conventionally, in order to shorten access time, the main efforts have been to reduce the weight of movable parts and increase driving force, but these measures have limitations. The present invention aims to shorten access time by shortening the access distance itself. When three objective lenses are used as in this embodiment, the recording area of each objective lens is approximately 100,000 yen compared to the conventional example in which only one objective lens is used. Since the amount of rotation becomes approximately equal to that, it becomes possible to access any position on the disc at high speed. Further, by providing a rotation angle detection sensor in the galvanometer mirror and a light flux position detection sensor in the vicinity of the objective lens, more accurate and faster access operations can be performed.

Although this embodiment shows the case where three objective lenses are used, any number of objective lenses may be used as needed.

Further, in this embodiment, the galvanometer mirror 2 is shown fixed to the rotating member 3, but it may be fixed to the pace 13 if necessary.

Effects of the Invention The present invention provides access means for an optical recording/reproducing device.
By using a fixed optical system, a galvanometer 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 flux position detection sensors, recording of a disk-shaped recording medium is possible. It is possible to realize an excellent optical recording and reproducing device that can access any position in the area at high speed and can achieve a significant shortening of the access means, which was difficult with conventional methods.

[Brief explanation of the drawing]

FIG. 1 and FIG. 1B are schematic diagrams of an optical recording and reproducing apparatus according to an embodiment of the present invention, and FIG. Figures 2B and 3 are schematic diagrams for explaining the operation;
FIG. 4 and FIG. 4B are schematic diagrams of a conventional optical recording/reproducing device. 1... Fixed optical system, 2... Galvano mirror 13... Rotating member, 4... Leaf spring, 6... Lens holder , 6a, 6b, 6C・
...Objective lens, 7...Disc, 8.
... Mirror, 9 ... Focus drive coil, 10 ... Focus drive magnet, 11 ...
... Access drive coil, 12... River/Access drive magnet, 13... Mountain... Pace, 14... Shaft, 16... Bearing, 3o... Rotation angle detection sensor, 311L/31b, 31(!...
...Light flux position detection sensor, 32...Photodetector, 33...Differential amplifier, 34.°...°Light flux. 8--Mirror 9-m-focus, @ moving coil IO-m-focus, connecting M-tong stone//---actu, @proboscis carp λν /2'--Aku-denu cantering moving stone 13 --Base 14---Shaft tS-1 Bearing is shown in Fig. 1 (B) Fig. 2 Fig. 3

Claims (1)

[Claims] A means for detecting a focus error signal on a disc-shaped recording medium, a means for detecting a tracking error signal on the disc-shaped recording medium, and a means for detecting a tracking error signal on the disc-shaped recording medium, which is composed of optical elements such as a semiconductor laser, a collimating lens, and a half mirror. a fixed optical system comprising means for detecting the above information signal; and a mechanism rotatable about an axis substantially parallel to an optical axis direction perpendicular to the recording medium surface of the disk-shaped recording medium. a galvano mirror that reflects the light beam from the fixed optical system in any direction within a plane substantially parallel to the recording medium surface of the disk-shaped recording medium; and a galvano mirror centered on an axis substantially parallel to the optical axis direction. a rotating member having a mechanism for driving the disc-shaped recording medium in a direction parallel to the recording medium surface and in a substantially radial direction; and a rotating member fixed to the rotating member, the disc-shaped recording medium objective lens driving means having a mechanism for driving a lens holder, which is arranged substantially linearly in a substantially radial direction of the disc-shaped recording medium, in the direction of the optical axis, including a plurality of objective lenses for forming a minute light spot thereon; and the same number of mirrors as the objective lens, which are fixed to the rotating member and are configured to make the light beam emitted from the fixed optical system enter approximately parallel to the optical axis of the objective lens, and the rotating member or the mirror. What is claimed is: 1. An optical recording and reproducing apparatus, comprising: a light flux position detecting means fixed to a lens holder; and having the same number of light flux position detection means as the objective lens and the mirrors for detecting the position of the light flux from the galvanometer mirror.