JPH0478025A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To absorb vibration generated in a magnetic yoke and to damp a resonance peak by interposing a damping member consisting of a vibration absorbing member and a weight member between a magnetic core and a carriage and providing a groove hole which receives the damping member in the carriage. CONSTITUTION:The damping member is interposed between the magnetic yokes 46a and 46b and the carriage 38. The damping member is constituted by superposing the weight member 73 and 74 on the vibration absorbing members 71 and 72 made of butyl rubber or silicone rubber and achieves an excellent vibration absorbing effect. The groove holes 75 and 76 are formed in the carriage 38 corresponding to the damping member so that the vibration absorbing ability may not be impaired. Thus, the resonance peak at the time of resonating the yokes 46a and 46b is damped.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical information recording/reproducing device used for an optical or magneto-optical recording medium such as an optical disk.

(Prior Art) As a conventional optical information recording/reproducing device, one is known that uses an optical system to record information on a recording medium when recording and erasing information.

Here, coarse access means accesses an optical head to an optical recording medium in order to record and reproduce information optically or magneto-optically, and fine access means accesses the optical head by fine adjustment with respect to the recording medium. means are provided.

That is, in order to record information on an information recording medium such as an optical disk, or to reproduce or erase recorded information, a light beam emitted from a light source such as a semiconductor laser is narrowed down to a minute spot of about 1 μm. In many cases, a method is used in which the light is projected onto the surface of the recording medium. In such a recording/reproducing apparatus, a linear voice coil motor is used as a rough access means for a so-called seek operation in which the optical head accesses a desired position on the recording medium. In addition, after the seek operation, focusing control is performed to correct out-of-focus caused by surface wobbling of the recording medium, etc.
An optical rad actuator is used to perform tracking control to correct positional deviation of the light beam spot due to eccentricity of the recording medium.

For example, in an optical head driving means as shown in FIG. 3, as a seeking means, a magnetic field generating coil (not shown) of a voice coil motor is attached to a carriage 16 on which the optical head is mounted, and its bobbin is attached to a screw hole. 18a, 18b
A pair of left and right yokes (not shown) each having a permanent magnet extending in a direction perpendicular to the winding direction of the coil are arranged opposite to the coil. There is. The carriage 16 is slidably supported on a guide rail (not shown) via bearings 19a and 19b, and a magnetic field is generated in accordance with the value of the current applied to the coil, and the carriage 16 is slidably supported on a guide rail (not shown). This realizes the movement of the carriage along the

Further, an optical head actuator is arranged on the carriage 16 as a means for finely adjusting the optical head. The above-mentioned actuator has a support shaft 16 vertically erected on a plate-shaped actuator frame 13 which also serves as a bottom yoke, and supports an objective lens holder 6 which is passed through a shaft hole 4 so as to be movable in the axial and rotational directions. , the holding body 6 is equipped with an objective lens 2 and a balance weight 5, a coil 7 for autofocusing is wound around the outer periphery of the holding body, a coil 8 for autotracking is provided thereon, and the coil 7 and 8, inner yokes 10a and lob, and outer yokes lla and l are attached with permanent magnets 9a and 9b on the frame 13 side.
lb is provided, and by supplying current to the coils 7 and 8, a magnetic field is generated, and the holder is moved relative to the support shaft, thereby performing fine adjustment of the objective lens.

The actuator is fixed to the carriage 16 with appropriate screws by aligning the holes 14a to 14d drilled in the frame 13 with the screw holes 15a to 15d drilled in the carriage 16.

The optical head exemplified here is one that has been applied to an information recording/reproducing device in which the optical system is separated into a movable part and a fixed part, and only the above-mentioned movable part is mounted. , there is an optical path for communication with the fixed part, for which apertures 17 and 20 are formed in the carriage.

In particular, in the fine movement access means, the objective lens holder 6 is provided with a neutral point holding mechanism. This includes, for example, a neutral point return method using an elastic support body made of silicone rubber, butyl rubber, or other elastic plastics, and a split-type light-receiving element and light source placed on the objective lens holder and the above-mentioned carriage facing it in the order in which they are listed. A method is adopted in which the position of the objective lens is optically detected and the position of the objective lens is detected in accordance with the position of the objective lens, and a reflection plate or a protrusion is fixed to the objective lens holder 6 and provided on the carriage side. There is a method of detecting when reflected light or a protrusion crosses an optical path using a light emitting element or a light receiving element.

(Problems to be Solved by the Invention) However, when the objective lens holder is driven in the focus direction, it often resonates at the natural frequency of the magnetic yoke itself. This hinders accurate positioning control of the objective lens, which in turn makes it difficult to control fine movement access.

(Object of the Invention) The present invention has been made based on the above circumstances, and is an optical information recording device equipped with a structure that damps vibrations in order to avoid resonance occurring in the objective lens holder based on the natural vibration frequency. The aim is to provide a playback device.

(Means for Solving the Problems) Therefore, the present invention provides coarse access means for accessing an optical head to an optical recording medium in order to record and reproduce information optically or magneto-optically, and the optical head. fine movement access means for accessing the recording medium by fine adjustment; the fine movement access means includes a coil for fine movement control of the objective lens on an objective lens holder that holds the objective lens; In an optical information recording/reproducing device having a magnetic yoke equipped with a permanent magnet, the magnetic yoke of the fine movement access means is mounted on the carriage of the coarse access means, and between the magnetic core and the carriage, A damping member consisting of a vibration absorbing member and a weight member is interposed, and a slot for receiving the vibration damping member is provided in the carriage.

(Function) Therefore, by the function of the vibration damping member and the corresponding slot, the vibration generated in the magnetic yoke can be absorbed and the resonance peak can be attenuated, and fine movement access control can be stably realized.

(Example) Examples of the present invention will be specifically described below with reference to FIG. In FIG. 1 (perspective view), reference numeral 1 denotes an information recording/reproducing apparatus according to the present invention, which is equipped with an optical held actuator as a means for finely adjusting the movable optical head of the separating optical system, as in the conventional example described above. There is. The above actuator consists of outer yokes 4.8a, 48b and bottom yoke 5.
L-shaped electromagnetic hook 46 integrally formed with 3a and 53b
a and 46b, and a support shaft 33 is vertically provided on the carriage 38 on the rough access means side to which these are attached, and the objective lens holder 31 is moved in the axial direction and rotational direction via a bearing 32. The holding body 31 is freely supported.
is equipped with an objective lens 34 and a balance weight 35,
An autofocusing coil 36 is wound around the outer periphery of the holder, and an autotracking coil 37 is provided thereon, and an inner yoke 54a is provided on the bottom yoke 53a side of the coils 36 and 37. and 5
4. b, and permanent magnets 47a and 47b are attached, and by supplying current to the coils 36 and 37, a magnetic field is generated, the holder is moved relative to the spindle, and the objective lens is finely adjusted. be.

The electromagnetic yokes 46a, 46b are provided with positioning pins 52a, 52b and 52c, 52d at the bottom,
A bottle hole 50a having these formed in the carriage 38,
51. a, 50b, and 51b, and is mounted on the carriage 38. In this case, the bottle hole 51a
, 51b are formed to be long to account for dimensional errors. The mounting holes 43a and 4 provided on the carriage 38 are
3b, and screws 49a and 49b to the electromagnetic yoke 46.
a and 46b are fixed to the carriage 38.

Note that the electromagnetic yoke is not constructed by cutting as in the past (it is preferably made by bending a root-shaped ferromagnetic material, or by forging or casting). It is preferable that one or more reinforcing ribs (not shown) are formed in each of the outer yokes 48a and 48a.
48b from falling (the grooves 55a and 55b corresponding to the reinforcing ribs can be seen in the figure).

In particular, in the present invention, a vibration damping member is interposed between the electromagnetic yokes 46a, 46b and the carriage 38. In this embodiment, the vibration damping members include weight members 73, 74 and vibration absorbing members 71, 72 made of butyl rubber, silicone rubber, elastic plastic, silicone, adhesive material, etc.
It is made up of layers of layers, and is designed to have a sufficient vibration absorption effect. In addition, in response to the above vibration damping member,
Slots 75 and 76 are formed in the carriage 38 so as not to impair its vibration absorbing properties. This attenuates the resonance peak when the electromagnetic yoke resonates.

In this embodiment, the carriage 38 is provided with bearing holes 44a to 44d, and bearings (not shown) provided in these are slid on guide rails to move and guide the optical head in the theta direction. Fulfill. Although not shown in this embodiment, a coil of a linear voice coil motor is provided as a coarse seek means, and a permanent magnet and a magnetic core for the voice coil motor are arranged correspondingly.

The carriage 38 is located below the objective lens 34.
A reflecting mirror 40 is attached to the optical path for the laser beam. Also, apertures 41, 42 are provided in the carriage for the optical path.

In the above embodiment, the support shaft and bearing means are used to finely adjust the objective lens, but the structure is not limited to this (for example, at least one leaf spring, Alternatively, a support method using a wire or the like, a support method using a hinge, etc. may be used.

Furthermore, in order to position the electromagnetic yoke on the carriage, positioning pins are provided on the electromagnetic yoke and positioning holes are provided on the carriage side, but these may be provided in the opposite manner. Further, the method for positioning the two is not limited to the above-mentioned method, but may be a method by fitting concave and convex portions, or a jig may simply be used. Additionally, screw holes may be provided on the carriage side to attach the electromagnetic yoke to the carriage.
Alternatively, use an epoxy or rubber-based adhesive or adhesive as shown in Figure 2.
The adhesive layer 105 may be provided by applying the adhesive layer 105 to a thickness of one layer (or this may be integrally molded with a resin having damping properties).

The reinforcing ribs in the above embodiments may be provided on the inner yoke, or may be provided on both the outer yoke and the inner yoke. Further, in this embodiment, the vibration damping member is provided on the lower side of the electromagnetic yoke, but its mounting position is not limited, and its structure may be, for example, a composite structure of several vibration damping members. However, a honeycomb shape may also be used, and the number thereof can be selected appropriately.

(Effects of the Invention) The present invention has been described in detail above, and when attaching the electromagnetic yoke of the fine movement access means to the carriage of the coarse access means, the vibration damping member made of a vibration absorbing member such as rubber or a weight member is attached to the electromagnetic yoke of the electromagnetic yoke. Since the electromagnetic yoke is interposed between the electromagnetic yoke and the carriage, and the carriage is correspondingly provided with a slot, the amplitude at the time of resonance at the natural vibration frequency set by the electromagnetic yoke and the magnet can be significantly reduced. Therefore, fine movement access can be achieved stably and quickly.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an apparatus showing one embodiment of the present invention, FIG. 2 is a perspective view showing a part of another embodiment, and FIG. 3 is a perspective view of a conventional example. 1. Information recording/reproducing device 31, . . . Objective lens holder 341. Objective lens 36 37a 37b, Coil 38, Carriage 46a, 46b, Electromagnetic yoke 47a 47b, Permanent magnet 54a, 54b, Inner yoke 71.72. , , Vibration absorbing member 73.741, Weight member 75.76, , Slot

Claims (1)

[Claims] coarse access means for accessing an optical head to an optical recording medium in order to optically or magneto-optically record and reproduce information; and fine access means for accessing the optical head by fine adjustment with respect to the recording medium. Equipped with
In an optical information recording and reproducing apparatus, the fine movement access means is provided with a coil for fine movement control of the objective lens on an objective lens holder that holds the objective lens, and a corresponding magnetic yoke with a permanent magnet. The magnetic core of the fine movement access means is mounted on the carriage of the coarse access means, and a vibration damping member consisting of a vibration absorbing member and a weight member is interposed between the magnetic yoke and the carriage, and the vibration damping member is interposed between the magnetic yoke and the carriage. An optical information recording/reproducing device characterized in that the carriage is provided with slots for receiving members corresponding to the members.