JPH11120572A - Objective lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a load time. SOLUTION: This device is an objective lens drive unit 10 loaded on an optical disk device answering to optical disks of plural specifications, and is provided with a lens holder 13 holding in line plural objective lenses 11, 12 individually answering to the optical disk of respective specifications, a support mechanism 2 supporting this lens holder 13 movably in the track direction and focus direction, an objective lens drive mechanism 3 biasing the movement of the lens holder 13 in the track direction and focus direction, a base 14 placing the lens holder 13 through the support mechanism 2, straight guide rails 15, 16 slidably supporting this base 14 and an biasing mechanism 4 for biasing the slide of the base 14, and the guide rails 15, 16 are arranged parallel to the arrangement direction of plural objective lenses 11, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device, and more particularly, to an objective lens driving device used for an optical disk device corresponding to a plurality of optical disks having different specifications.

[0002]

2. Description of the Related Art FIG. The conventional objective lens driving device 50 is disclosed in Japanese Patent Application Laid-Open No. Hei 9-17005. This objective lens driving device 50
Reads and writes (hereinafter referred to as R / W) both CDs and media such as DVDs with different substrate thicknesses from CDs
I do.

In FIG. 3, reference numerals 52 and 53 denote objective lenses of an optical head used in an optical disk device. One objective lens 52 is used for a CD, and the other objective lens 53 is used for a DVD. These objective lenses 52 and 53 are fixedly held by a lens holder 54.

The lens holder 54 has four wires 5
5, 56, 57, and 58, it is supported by the fixed portion 59 so as to be movable in the focus direction (Z direction in FIG. 3) and the track direction (X direction in FIG. 3). The four wires 55 to 58 allow the lens holder 54 to move in the above-described directions by bending.

[0005] The fixing portion 59 is fixedly mounted on a base 60. On the base 60, two magnetic circuits 61 are provided so as to sandwich the lens holder 54, and the magnetic circuit 61 allows the lens holder 54
Is moved in the focus direction and the track direction.

[0006] The above-mentioned base 60 is provided with four link members 62 and 63 (two are not shown) on the main body H of the optical disk apparatus.
Are connected via Each link member 62, 63
The optical disk device is rotatable in the XZ plane about the main body H side. In addition, the turning operation is biased by the turning of an arm member 64 connected to a drive motor (not shown). That is, this base 60
Are supported by a parallel link mechanism.

A raising mirror (not shown) is provided below the base 60, and the laser light irradiated along the X direction is raised in the Z direction. In FIG. 3, the optical axis of the laser light passes between the objective lenses 52 and 53. Therefore, when performing R / W on a CD, the link members 62 and 63 rotate to the right to rotate the objective lens 52.
The base 60 is moved rightward so that is on the optical axis.
When performing R / W on a DVD, the base 60 is moved to the left so that the link members 62 and 63 rotate to the left and the objective lens 53 is on the optical axis.

[0008]

In the prior art, since the base 60 is supported by a parallel link mechanism, when the objective lenses 52 and 53 are switched, the base 60 is connected to each of the link members 62 and 53. It moves along an arc having a radius of 63. Therefore, each link member 62, 63
The base 60 moves up and down with the top of the base 60 facing the Z-axis direction.

On the other hand, the distance between the objective lenses 52 and 53 and the optical disk at the time of R / W is close to each other, and it is difficult to secure a sufficient distance to allow the base 60 to move up and down. In particular, in the case of a type in which an optical disc is stored in a case and R / W is performed through a window provided in the case, it is almost difficult to secure a separation distance because the case is interposed between the objective lens and the optical disc. Was.

Therefore, the conventional optical disk device needs a function of identifying the type of the optical disk from which the loading has been started in advance and switching the objective lens before the loading of the optical disk is completed.

However, normally, the mechanism is such that the load is immediately reduced when the medium is recognized, and the switching timing of the objective lens driving device is not considered. Therefore, there is a disadvantage that it is necessary to consider the switching timing, and there is a risk of contacting the cartridge or the medium if the switching timing is incorrect.

In particular, the prolonged loading time of the cartridge is a very serious drawback of the apparatus.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide an objective lens driving device which can solve the disadvantages of the prior art and can reduce the load time.

[0014]

SUMMARY OF THE INVENTION The present invention is directed to an objective lens driving device provided in an optical disk device corresponding to an optical disk of a plurality of specifications, wherein a plurality of objective lenses individually corresponding to optical disks of each specification are arranged in a line. A lens holder for holding the lens holder in the track direction and the focus direction, and a supporting mechanism for freely moving the lens holder in the track direction and the focus direction; an objective lens driving mechanism for urging the lens holder to move in the track direction and the focus direction; A base on which the lens holder is mounted via a support mechanism, a straight guide rail for slidably supporting the base, and an urging mechanism for urging the base to slide; The optical disk device is provided along the arrangement direction of.

Here, the above-mentioned track direction refers to a direction crossing a plurality of tracks on the optical disk, and the focus direction refers to a direction perpendicular to the disk surface of the optical disk.

In the above configuration, the objective lens corresponding to the type of the optical disk to be loaded is positioned on the optical axis of the laser light by sliding the base along the guide rail. Then, tracking and focusing are performed by the objective lens driving unit, and thereafter, R / W for the optical disk is performed.

Here, the plurality of objective lenses may be arranged along the track direction.

Also, two guide rails described above are provided,
Each of these guide rails may be configured to support one end and the other end of the base.

Further, the aforementioned urging mechanism may be configured to use a voice coil motor as a drive source.

Further, the above-mentioned lens holder may be configured to hold two objective lenses.

The present invention is intended to achieve the above-mentioned object with the above-described configuration.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. This embodiment is directed to an objective lens driving device 1 provided in an optical disk device corresponding to optical disks of two types of specifications.
0 is shown.

The objective lens driving device 10 includes two objective lenses 1 individually corresponding to optical discs of two kinds of specifications.
A lens holder 13 for holding the lens holders 1 and 12 in a line, a support mechanism 2 for supporting the lens holder 13 so as to be freely movable in the track direction and the focus direction, and a movement mechanism for the lens holder 13 in the track direction and the focus direction. An objective lens driving mechanism 3 to be urged, a base 14 on which a lens holder 13 is placed via a support mechanism 2,
Straight guide rails 15 and 16 for slidably supporting 4
And a biasing mechanism 4 for biasing the base 14 to slide.

Hereinafter, each part will be described in detail.

Here, according to FIG. 1, the X direction indicates the track direction (radial direction) of the loaded optical disk, of which the upper side in FIG. 1 is the INNER side and the lower side is the OU side.
TER side. The Y direction indicates the tangential direction (the tangential direction of the track). In addition, Z shown in FIG.
The direction indicates a focus direction (a direction perpendicular to the surface of the optical disk).

The above-mentioned optical disk device supports two types of optical disks, CD and DVD. Since these optical disks have different focal lengths, the objective lens driving device 10
The objective lens 11 for CD and the objective lens 12 for DVD are held by a lens holder 13.

Each of the objective lenses 11 and 12 is held by a lens holder 13 side by side along the X direction with the optical axis parallel to the Z direction. The lens holder 13 is supported on the base 14 by the support mechanism 2.

The support mechanism 2 includes four leaf springs 21 for focusing, which support the lens holder 13 at the distal end thereof.
2 and 23 (one sheet is not shown) and a relay member 2 for holding rear ends of these leaf springs 21, 22 and 23 for focusing.
4, a tracking leaf spring 25 for supporting the relay member 24 at its tip, and a tracking leaf spring 25.
And a fixed base 26 fixedly mounted on the base 14 holding the rear end of the base.

Each leaf spring 21, 22, 2, 2 for focusing
Numeral 3 denotes a rod-shaped leaf spring, the tip of which is fixed above and below both ends of the lens holder 13 in the X direction. Each of the focusing leaf springs 21, 22, 23 is arranged such that its longitudinal direction is parallel to the Y-axis direction and its flat surface is parallel to the XY plane. Therefore, each of the focusing leaf springs 21, 22, and 23 is
The lens holder 13 flexes around the direction, and swings freely along the focus direction (Z direction).

On the other hand, the tracking leaf spring 25 is
The relay member 24 is arranged parallel to the Z plane, flexes around the Z direction, and swings the relay member 24 freely with respect to the fixed base 26 in the track direction (X direction). Therefore, the lens holder 13 can move in the track direction and the focus direction with respect to the base 14.

Next, the objective lens driving mechanism 3 will be described. The objective lens driving mechanism 3 includes a lens holder 13
, Two magnets 31, 32 mounted on the base 14 so as to sandwich the lens, a focusing coil 33 wound along the periphery of the lens holder 13, and four corners of the lens holder 13 via the focusing coil 33. Tracking coil 34 attached to the
35, 36, and 37.

When the focusing coil 33 is energized, the focusing coil 33 urges the lens holder 13 in the Z direction by the action of the magnetic field generated by the magnets 31 and 32. Further, the tracking coils 34, 3
When power is supplied to the magnets 5, 36, 37, the magnets 31, 32
And a magnetic field generated by the lens holder 13 urges the lens holder 13 to move in the X direction.

Next, the base 14 will be described. The base 14 is formed in a flat plate shape, on which the lens holder 13, the supporting mechanism 2, and the objective lens driving mechanism 3 are mounted. Both ends in the Y direction of the base 14 are supported by guide rails 15 and 16, respectively.

Each of the guide rails 15 and 16 is mounted on the optical disk apparatus main body H along the track direction (X direction). The base 14 is connected to the guide rail 15 via one bearing 17 and is connected to the guide rail 16 via two bearings 18 and 19. Each of the bearings 17, 18, and 19 is a linear motion bearing, whereby the base 14 is movable in the track direction.

The lower part of the base 14 and the optical disk apparatus main body H
Between the guide rails 15, 16
Is provided with an urging mechanism 4 for reciprocating in the direction along. The urging mechanism 4 uses a voice coil motor (not shown) as a drive source.

The objective lens driving device 10 having the above configuration
Will be described.

Below the base 14, a rising mirror (not shown) for raising the laser light irradiated along the XY plane in the Z direction is provided. The laser light reflected by the rising mirror passes through a point R in FIG.

First, when reading data from a CD, the urging mechanism 4 moves the base 14 to the OUTER in the X direction.
Move to the side. Thereby, the objective lens 11 is positioned at the passing point R of the laser light. Then, tracking and focusing are performed by the objective lens drive function 3, and reading from the CD is performed.

When reading from a DVD, the urging mechanism 4 moves the base 14 in the X-direction INNE.
Move to the R side. Thereby, the objective lens 12 is positioned at the passing point R of the laser light. Then, tracking and focusing are performed by the objective lens driving function 3, and reading from the DVD is performed.

As described above, the objective lens driving device 1
The reference numeral 0 indicates that two types of objective lenses are held and can be switched between them. Therefore, by equipping the optical disk apparatus with the present apparatus 10, it is possible to perform R / W on two types of optical disks.

Further, guide rails 15, 16 parallel to the arrangement direction of the objective lenses 11, 12 on the lens holder 13.
In order to switch the objective lens by moving the base 14 along, the base 14 moves linearly,
There is no need to secure a wide moving area for the base 14.
Therefore, it is possible to reduce the size of the entire device.

Further, by having two guide rails 15 and 16 and being supported at one end and the other end of the base 14, occurrence of rattling when the base 14 is moved is effectively prevented, and smooth movement is achieved. In addition, it is possible to perform the switching operation of the objective lens at the same time, and it is possible to improve the positioning accuracy.

Further, since the driving source of the urging mechanism 4 is provided with the voice coil motor, it is possible to position the objective lens on the optical path of the laser light in a minute distance unit when switching the objective lens. In addition, it is possible to further improve the positioning accuracy.

The urging mechanism 4 is not particularly limited to a voice coil motor as a driving source, and any other servo motor, linear motor, or the like may be used as long as it can urge a linear motion. .

Here, the objective lens 1 for CD and DVD
The arrangement of the lenses 1 and 12 may be reversed, and a configuration in which three or more objective lenses are mounted to support an optical disk having more specifications may be adopted. Also, for the optical disc, C
By providing an objective lens corresponding to another optical disk without being limited to D and DVD, it is possible to support the optical disk.

[0046]

The present invention holds a plurality of objective lenses,
Since this can be switched freely, it is possible to perform R / W on a plurality of types of optical disks by equipping the optical disk device with the present invention.

Further, since the objective lens is switched by moving the base along a guide rail parallel to the arrangement direction of the plurality of objective lenses on the lens holder, the base moves linearly. Therefore, unlike the conventional case, the base does not move on a circular arc, and it is not necessary to secure a time for switching the objective lens from the start to the end of loading even for an optical disc in a case. That is, it is possible to reduce the load time. Further, it is possible to switch the objective lens even when the optical disk is mounted in the apparatus. Further, it is not necessary to secure a wide moving area of the base, and it is possible to reduce the size of the entire apparatus.

When a plurality of objective lenses are arranged in the track direction, the objective lens can effectively cope with an optical disk in a case having a slot-shaped open / close window for R / W along the same direction. Reading can be performed. That is, since the optical disk and the objective lens need to be close to each other,
When the lens holder is in a case, it may be necessary to make the lens holder enter the inside of the R / W window. In this case, since the longitudinal direction of the R / W window coincides with the arrangement direction of the objective lens, it is possible to switch the objective lens even when the optical disk is mounted in the apparatus.

Also, by using two guide rails and supporting them at one end and the other end of the base, it is possible to effectively prevent rattling during movement of the base and to smoothly switch the objective lens. This makes it possible to improve the positioning accuracy.

Further, when the biasing mechanism is provided with a voice coil motor, it is possible to position the objective lens on the optical path of the laser beam in a minute distance unit when switching the objective lens, thereby further increasing the positioning accuracy. Can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of an objective lens driving device according to an embodiment of the present invention.

FIG. 2 is a side view of the objective lens driving device.

FIG. 3 is a perspective view of a conventional objective lens driving device.

[Explanation of symbols]

 Reference Signs List 2 Support mechanism 3 Objective lens drive mechanism 4 Urging mechanism 10 Objective lens drive device 11, 12 Objective lens 13 Lens holder 14 Base 15, 16 Guide rail

Claims (5)

[Claims] 1. An objective lens driving device provided in an optical disc device corresponding to optical discs of a plurality of specifications, comprising: a lens holder for holding a plurality of objective lenses individually corresponding to the optical discs of the respective specifications in a line; A support mechanism for freely supporting the lens holder in the track direction and the focus direction; an objective lens driving mechanism for urging the lens holder to move in the track direction and the focus direction; and the support for the lens holder. A base mounted via a mechanism, a straight guide rail that slidably supports the base, and an urging mechanism that urges the base to slide, wherein the guide rail is provided for the plurality of objective lenses. An objective lens driving device, which is disposed in parallel with the arrangement direction. 2. The apparatus according to claim 1, wherein the plurality of objective lenses are arranged along the track direction.
The objective lens driving device as described in the above. 3. The objective lens drive according to claim 1, wherein two guide rails are provided, and each of the guide rails supports one end and the other end of the base. apparatus. 4. The objective lens driving device according to claim 1, wherein said biasing mechanism includes a voice coil motor. 5. The objective lens driving device according to claim 1, wherein the lens holder holds two objective lenses.