JPS63244417A - Information reproducing device - Google Patents

Abstract

PURPOSE:To attain accurate tracking control even at the time of high speed accessing by providing a support means applying position adjustment to a light collecting means only in the optical beam axis. CONSTITUTION:The optical system 11 consists of a laser light source 13, a collimator lens 15 converting a beam light 12 into a collimated beam light 14, a galvano mirror 16 as a deflection means deflecting the collimated beam light 14 into a direction at a right angle to the turning face of an optical disk 1 and an objective lens 18 as a light collection means collecting the deflected collimated beam 17 onto a recording layer 7 of the optical disk 1. Moreover, a guide cylinder 38 acting also like an adjusting member being a stationary member is fitted to a voice coil 37, the guide cylinder 38 is inserted in a cavity 39 at the center of a yoke 35 slidably freely in the vertical direction to support the voice coil 37 and the objective lens 18 so as to be moved in the direction 40 of beam optical axis and not to be moved in a direction 41 at a right angle to the tracking direction of the optical disk 1. Thus, the light collecting means is not vibrated and accurate access is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an information reproducing device that reproduces information stored in, for example, an information storage medium.

(Prior Art) In recent years, various image filing devices have been developed that sequentially file (memorize) information such as increasingly increasing documents and retrieve and retrieve desired information as needed. Among image filing devices, optical disk devices have been put into practical use that use optical disks as information storage media to store necessary information and to search and read out the stored information.

This optical disk device converts black and white information on the document surface into an electrical signal, that is, an analog signal, by optically reading and scanning the document surface to be stored with a laser beam.
This analog signal is subjected to FM modulation to produce a recording signal. Then, C1 uses this recording signal to perform on-on modulation on the laser beam generated by the laser light source, and irradiates the recording layer of the optical disc rotating at a constant speed with the modulated laser beam to illuminate the irradiated area. Change and record optical properties.

To read the information recorded on the recording layer of this optical disc, the optical disc is rotated at a constant speed.
A beam of constant intensity is irradiated onto 1 on the optical disk along the rack, and the modulation state of the reflected light from the recorded portion is electrically jj,>jL converted to read information.

However, in this type of optical disk device, the entire optical system including the laser light source is conventionally mounted on one movable base, and this movable base is moved in the radial direction of the optical disk by a linear drive means, and any arbitrary position on the optical disk is moved. I was trying to read out the information stored in Track J.

However, since the entire optical system including the laser light source is mounted on one movable base, the linear drive means must move the large heavy object 11, and it is necessary to move the large weight 11 to a specified position on the optical disk. The problem was that high-speed access to the track was difficult.

Therefore, for the purpose of realizing high-speed access, in order to lighten the load on the linear drive means, the optical system is equipped with a fixed part including a laser light source and a collimator means, and a remeter means for deflecting the collimated beam of light. and a condensing means for condensing the collimated beam onto a predetermined track F, and racking is performed by moving only the movable section C by the linear drive means. So-called separate heads are beginning to appear.

However, in the case of an optical disc equipped with this separate head, generally both the tracking deviation adjustment and the defocus adjustment are performed by controlling the position of the objective lens as a light focusing means, so the linear drive means is used. When accelerating at high speed, the condensing means vibrates, making it difficult to perform accurate tracking control.

(Problems to be Solved by the Invention) As described above, in an information reproducing device such as an optical disk device equipped with a conventional separation type head, a predetermined track "-7"
There was a problem that accurate tracking control could not be performed when accessing \ at high speed.

The present invention has been made to overcome these conventional problems, and an object of the present invention is to provide an information reproducing apparatus that can perform accurate tracking control even during high-speed access.

1. Structure of the Invention" (Means for Solving the Problems) An information reproducing apparatus of the present invention includes a laser light source that generates a beam of light to be irradiated onto an information storage medium having a tracking guide, and a beam that is generated from the laser light source. collimator means for converting light into parallel beam light; deflection means for deflecting the parallel beam light formed by the collimator means;
an optical system having a condensing means for condensing the parallel beam light deflected by the deflection means onto the information storage medium;
a moving means for moving both the deflection means and the condensing means of the optical system in the radial direction of the information storage medium; and a movement means for preventing the condensing means from moving in a direction perpendicular to the tracking guide of the information storage medium. The present invention is characterized in that it comprises a fixing member fixed in this manner, and a support means having an adjusting portion for adjusting the position of the condensing means with respect to the beam axis direction.

(Function) In the information reproducing apparatus of the present invention, a beam of constant intensity from a laser light source is irradiated onto a predetermined track of an information storage medium, and the optical characteristics of the reflected light from the irradiation spot on this track are changed. Read memory information.

At this time, the deflection means covers the beam axis adjustment in the direction perpendicular to the tracking guide so that the beam light irradiates a predetermined 1-rack on the information storage medium.

Further, the supporting means for the light condensing means is such that the light condensing means does not move in a direction perpendicular to the tracking guide and can be adjusted only in the beam axis direction, so that the light beam is focused on a predetermined track of the information storage medium. It is possible to adjust the position of the condensing means so that the light is emitted.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of the invention. The optical disc 1 of the information storage medium (2) is usually made by combining a pair of disc-shaped transparent plates 2.3 with a spacer 4.5, and a metal heat film is applied to the inner surface of each transparent plate 2, 3. This is the structure in which the storage layer 6.7 is formed by.

The center of the optical disc 1 is engaged with the spindle 9 of the disc drive motor 8, and the chucking member 1
It is fixed at zero and rotates at high speed.

The optical system 11 includes a ray light source 13 that generates a beam of light 12 that is irradiated onto the rotating optical disk 1, and a parallel beam of light 14 that converts the beam of light 12 generated from the laser light source 13 into a parallel beam of light 14.
A collimator lens 15 consisting of a convex lens that converts the light into It is provided with an objective lens 18 as a focusing means for condensing the parallel beam 17 deflected by the galvanometer mirror 16 onto the recording layer 70 of the optical disc 1.

Further, this optical system 11C is provided with one beam splitter and a quarter wavelength plate 20 on the collimator 15 side.

Furthermore, the optical system 11 is also provided with a photodetector 21 . This light detection unit 21 includes a half prism 22, condensing lenses 23.24 located in two directions perpendicular to the half prism 22, and photodetectors 25.26 corresponding to each condensing lens 23.24. and a boolean edge 27 provided for one of the condensing lenses 24. The condensing lens 23 is a reproduction/1-Funking deviation detection system 28. The condenser lens 24 is part of the defocus detection system 29.

The knife 27 extracts the beam spot asymmetrically with respect to the optical axis, and may be a light shielding plate C) provided with a light passage hole or slit at an eccentric position.

Said Rede light source 13. Collimator lens 15° Beam splitter 19 and 1/4 wavelength plate 20° Rough detection unit 2
Condensing lenses 23, 24 and photodetector 25.2 constituting 1
6 and the knife 27 are fixed and separated from the galvanometer mirror and the objective lens. These objective lenses 18 such as the galvanometer mirror 16 can be driven in the radial direction of the optical disc 1 by a linear drive device 30 as a moving means.

The galvanomirror 16 is provided with a galvanomirror drive device 31 as a deflecting means, which is tilted in a direction perpendicular to the direction of tracking force on the optical disk 1 by the 4E+moon of a tracking deviation adjuster 32, thereby correcting the tracking deviation. It looks like this.

A voice coil drive device 33 is provided as a support means for the objective lens 18.

As shown in FIG. 2, this voice coil drive device 33 is composed of a permanent magnet 34, a yoke 35, and a voice coil 37 inserted into a magnetic gap 36 of this yoke 35.
An objective lens 18 is attached to the voice coil 37. Further, a guide tube 38 is attached to the voice coil 8-37, which is a fixed member and also works as an adjusting section Δ and C. , the voice coil 37 and the objective lens 18 move only in the beam optical axis direction/IQ, and the ! of the optical disc 1 is inserted. - It is supported so as not to move in a direction 41 perpendicular to the racking direction (horizontal direction in the figure).

In this voice coil drive device 33, a voice coil 37 is driven by a signal from the photodetector 26 shown in FIG.
The objective lens 18 is moved by the required amount in the optical axis direction 40 by this movement of the voice coil 37, and the focus position is adjusted so that the collimated beam 17 is focused on the recording layer 71 of the optical disc 1.

This boil coil drive device 33 may have a configuration as shown in FIG. The voice coil drive device 33 shown in FIG.
5, and a gimbal spring 46 between the outer circumference of the voice coil 45 and the inner circumference of the yoke 43.

The operation of the information reproducing apparatus having the above configuration will be described next.

When recording information on the optical disc 1, the optical disc 1 is rotated at high speed by the disc drive motor 8,
The objective lens 18 and the galvanometer mirror 16 are accessed to a predetermined track position on the optical disk 10 by the linear drive device 30. Thereafter, a laser beam 12 whose intensity is modulated according to the recorded information is generated from a laser light source 13, and a parallel beam 14 is generated by a collimator lens 5.
The beam is transmitted through the beam splitter 19. And 1
It passes through the /4 wavelength plate 20 and enters the guide mirror 16, where the optical axis is deflected at a right angle of 90 degrees and the objective lens 1
8. The objective lens 18 narrows down the parallel beam 17 and focuses it on a predetermined position on the recording layer 7 of the disk 1, changing the optical characteristics of the irradiated area to form bits and recording them.

When reproducing the recorded information on the optical disc 1, the objective lens 18 and the guide mirror 16 are moved and positioned to a predetermined track by the linear drive device 30 while the optical disc 1 is rotated, and the laser light source 13 is used to A laser beam 12 with an intensity of . The light enters the objective lens 18 through the galvanometer mirror 16, where it is focused and released onto the optical disc 1.
A predetermined position on the recording layer 7 is irradiated.

In the recording layer 7 of the optical disc 1, the reflected light modulated by the bits of the irradiated area becomes a parallel beam light 17 again by the objective lens 18, and is transmitted through the galvanometer mirror 16 and quarter wavelength plate 20 to the C beam splitter 19. Ezuru. here,
In the case of reflected light, the outgoing envelope and r1//I wave plate 20 are
The plane of polarization is rotated by 90 degrees because the light passes through the beam splitter 19, and the light passes through the beam splitter 19 and advances toward the half prism 22 of the photodetector 21. Then, the C1 half prism 22'c is divided into halves, and a part of the reflected light is transmitted through the condenser lens 23 of the reproduction/tracking deviation detection system 28 and connected to the beam switch 1~ to the photodetector 25), where it is photoelectrically converted. play 15
It is extracted as a number. This spot 1~ of the photodetector 25 is also used to adjust the tracking deviation at the same time.
The tracking deviation adjuster 32 adjusts the correction number 1 to 43 according to the size of the tracking deviation to the galvano mirror drive device 31.
, the galvano mirror drive device 31 is driven according to the tracking deviation, and the galvano mirror 16 is tilted to adjust the tracking deviation.

In addition, a part of the reflected light refracted by the half prism 22 passes through the condenser lens 24 of the defocus detection system 29, is partially blocked by the knife edge 27, and then reaches the photodetector 26, causing the defocus to be detected. Used for adjustment.

To explain this defocus adjustment operation, when the focal point of the objective lens 18 matches the recording layer 7 of the optical disc 1, the repulsed light from the recording layer 7 passes through the objective lens 18 again, so that the parallel beam light 17 The light passes through the half prism 22 and reaches the condenser lens 24. Therefore, the light beam transmitted through the condenser lens 24 is focused on the photodetector 26, forming a round beam spot 1- in the center a of the photodetector 26.

However, if the bits of the recording layer 7 and the objective lens 18 are too close to each other and cannot be brought into focus, the reflected light passing through the objective lens 18 will gradually spread outward away from the optical axis, causing the knife 27 to The beam spot of the passing Ic light is shifted to the + side from the center position. On the other hand, if the recording layer 7 is too far away from the objective lens 18 and cannot be focused, the reflected light passing through the objective lens 18 is narrowed inward so that it gradually approaches the optical axis. The light comes to be focused in front of the detector 26, and the beam spot created by the light that has passed through the bias edge 27 on the photodetector 26 is shifted from the center position in the leet direction C.

Therefore, the photodetector 26 detects the defocus by the positions a and -C of the beam spot 1- which overlaps the -1-, and adjusts the position of the -C objective lens 18 with respect to the voice-1 illumination drive device 33. Provide the necessary drive signal for the

A galvanometer mirror 16 is provided in the radial direction of the optical disk 1.
When moving the objective lens 18, the linear drive device 30 as a moving means is driven, and the galvano mirror 16 is moved.
Only the objective lens 18 is separated from the other constituent members of the optical system 11 and moved.

In the case of this radial movement, since the laser beam from the laser light source 13 passes through the collimator lens 15 and becomes a parallel beam 14, it also enters the galvanometer mirror 16 as a parallel beam. Therefore, even if the distance between the galvano mirror 16 and the beam splitter 19 changes, the diameter of the focused spot on the optical disk 1 does not change at all.

Therefore, the galvano mirror 16 is driven by the linear drive device 30.
and the objective lens 18 is moved in the radial direction of the optical disk 1 to form pits on arbitrary tracks of the recording layer 7 of the optical disk 1 and to read bits on arbitrary tracks on the optical disk 1. This is possible.

When only the galvanometer mirror 16 and the objective lens 18 are moved in the radial direction of the optical disc 1 in this way, the linear drive device 30 as a moving means can be made smaller and lighter. and,
When performing access, the objective lens is fixed in the direction perpendicular to the direction of the tracking guide and can be moved only in the optical axis force plane, and tracking control is performed by the galvanomirror drive device 31. This reduces the possibility that the single-object lens 18 will shift in a direction perpendicular to the tracking direction due to vibrations caused by slanting shift, and accurate tracking can be realized.

As a result, by reducing the size and weight of the movable parts 16 and 18 of the optical system 11 and moving and stopping them at high speed, smooth high-speed axle can be achieved.

Although the above embodiment describes an information reproducing device that also has a recording function using an optical disk, the present invention is not limited to the above embodiment, and can be applied to an information reproducing device that has only a reproducing function. It can also be applied to

Effects of the Invention As described above, according to this invention, the separated type l\rad 1
5- Since it is equipped with an optical system, the moving means can be made smaller and lighter, allowing for high-speed movement and stopping.

The direction of the C1 parallel beam light is controlled by the deflection means, and the converging means is provided with a support means for adjusting the position only in the direction of the beam optical axis, and movement in a direction perpendicular to the tracking direction is prevented. Therefore, when accessing a predetermined track by the moving means, the condensing means does not vibrate, and accurate access can be achieved even under high conditions.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram of an embodiment of the present invention, FIG. 2 is a sectional view of a voice coil drive device used in the above embodiment,
FIG. 3 is a sectional view showing another embodiment of the voice coil drive device. 1... Optical disk 8... Disk drive motor 11... Optical system 13... Laser light source 15.
...Collimator lens 16...Galvanometer mirror 18...Objective lens 21...Primary detection section 30...
・Linear drive device

Claims (1)

[Claims] A laser light source that generates a beam light to be irradiated onto an information storage medium having a tracking guide, a collimator means that converts the beam light generated from the laser light source into a parallel beam light, and a parallel beam formed by the collimator means. an optical system comprising: a deflecting means for deflecting a parallel beam of light; and a focusing means for focusing the parallel beam of light deflected by the deflecting means onto the information storage medium; a moving means for moving the light means together in the radial direction of the information storage medium; a fixing member that fixes the light condensing means to prevent movement at right angles to a tracking guide of the information storage medium; 1. An information reproducing device comprising: a support means having an adjusting member for positionally adjusting the optical means in the beam axis direction.