JP3524861B2 - Optical disk drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for recording or reproducing on a disk, and more particularly, it has a tilt servo mechanism capable of tilting an optical pickup by following a surface inclination due to the warp of the disk. The present invention relates to an optical disk device.

[0002]

2. Description of the Related Art Generally, in an optical disc apparatus of this type, in order for the optical pickup to accurately read a signal recorded on the recording surface of the disc, the optical axis of the optical pickup is relative to the recording surface of the disc. It is desirable that the disc is perpendicular to the track direction and the radial direction.

An optical disk reproducing apparatus such as a DVD (Digi
In a reproducing device such as a tal versatile disk), a CD, a magneto-optical disk, a tilt sensor detects a warp amount of the disc in a radial direction of the disc (hereinafter referred to as a radial direction), and the detected warp amount is determined by the tilt amount. Accordingly, tilt servo is performed to tilt the optical axis of the optical system lens of the optical pickup.

Hereinafter, a tilt servo mechanism of a conventional optical disk device will be described with reference to FIGS. 7 to 10. FIG. 7 is a plan view showing an example of a conventional optical disk device, and FIG. 8 is a side view of the same. FIG. 9 is a plan view of the essential parts showing the position of the switch cam when the switch for detecting the rotation direction of the cam gear in the conventional optical disk device is in the ON state, and FIG. 10 shows the position of the switch cam when the switch is in the OFF state. It is a principal part top view.

In FIG. 7, the optical pickup unit 3
A tilt sensor 2 for detecting the tilt of the disc 1 (broken line portion not shown) in the radial direction is attached to the optical pickup unit 3, and the optical pickup unit 3 is attached to two guide shafts 4 in parallel and freely movable in the radial direction of the disc 1. It is attached and the two guide shafts 4 are fixed to the traverse chassis 5.

Further, as shown in FIG. 8, the disk 1 installed on the uppermost surface is attached to a turntable 6a which is rotationally driven by a spindle motor 6, and the spindle motor 6 is fixed to a base chassis 7.

Next, the fulcrum shaft 5 of the traverse chassis 5
c, the bearing 5b, the bearing 7a provided on the base chassis 7,
The traverse chassis 5 is fitted to the fulcrum shaft 7b and is attached to the base chassis 7 so as to be vertically rotatable. A cam follower 5a is fixed downward at one end (the left end in FIG. 8) of the traverse chassis 5 in the guide shaft 4 direction.

As shown in FIG. 7, a cam gear 9 having a cam portion 9a on its inner peripheral portion is mounted on the base chassis 7 so as to be rotationally driven by a cam drive motor 10 via a reduction mechanism 11. The cam drive motor 10 is rotationally driven based on the output of the tilt angle of the traverse chassis 5 detected by the tilt sensor 2.

A cam follower 5a of the traverse chassis 5
The cam follower 5a of the traverse chassis 5 can be vertically swung about the fulcrum shafts 5c and 7b by rotationally driving the cam gear 9 in a state where it is in contact with the cam portion 9a. As a result, the optical pickup can be tilted by following the surface inclination due to the warp of the disc 1.

Further, in the conventional optical disk device, the fulcrum shafts 5c, 7 of the traverse chassis 5 and the base chassis 7 are provided.
Two coil springs 12 are used, one at each of the two fitting portions, in order to eliminate looseness of the gap generated in the radial direction at the fitting portion between the b and the bearing portions 5b and 7a. . As shown in FIG. 8, both ends of the coil spring 12 are fixed to the traverse chassis 5 and the base chassis 7, respectively, and urge them to draw each other in the horizontal direction.

A single coil spring 13 is used to urge the traverse chassis 5 downward (toward the cam portion 9a). As shown in FIG. 8, both ends of the coil spring 13 are fixed to the traverse chassis 5 and the base chassis 7, respectively, and urge each other to vertically attract each other.

As described above, the conventional optical disk device requires a total of three coil springs 12, 13 of two types.

Next, in the conventional optical disk device, as shown in FIG. 9, the end of the cam portion 9a of the traverse chassis 5 is detected, so that the rotational position of the cam gear 9 is detected at a position different from the cam gear 9. Switch 18 for each
A part of the switch cam portion 9b, which is provided inside the cam gear 9 and has a tapered shape, is engaged with one end of an arm 16 that rotates about the arm shaft 15 to operate, and the other end portion of the arm 16 rotates. The switch 18 is operated to detect the position of the cam gear.

Here, the rotation-unnecessary range of the cam portion 9a corresponds to the circumferential portion of the switch cam portion 9b having a large radius, and the arm 16 in the switch cam portion 9b shown in FIG.
Is on the left side in the figure (the circumference of the switch cam portion 9b having a large radius is located on the left side, so the arm 1
6 is in the leftmost position), the switch 18 is in the on state, and when the switch 18 is in the range from the off state due to the cam rotation operation, the cam portion 9
It is controlled so that the direction of the rotational movement of a is reversed and the switch 18 returns to the off position.

At that time, the position of the traverse chassis 5 is in the uppermost position when the cam portion 9a is switched from the right rotation to the switch 18 off state, and is most downward when the cam portion 9a is rotated from the left rotation to the switch 18 off state. It will be located.

Also, as shown in FIG. 10, when the rotation range of the cam portion 9a corresponds to the small radius portion of the switch cam portion 9b, the arm 1 of the switch cam portion 9a is formed.
6 is on the right side in the figure (that is, since the circumference of the switch cam portion 9b having a large radius is located on the right side, the engaging portion with the arm 16 located on the opposite side of the circumference having a small radius). Is located on the right side of the position shown in FIG. 9), the switch 18 is turned off.

That is, the switch 18 is normally controlled to be in the off state, and the cam follower 5a and the cam portion 9a rotate while making contact with each other within a range where the radius of the switch cam portion 9b is small, and the angle of the traverse chassis 5 is increased. Is variably controlled to perform tilt servo control.

[0018]

However, in the above-mentioned conventional optical disk device, the radial generated at the fitting portion between the fulcrum shafts 5c and 7b of the traverse chassis 5 and the base chassis 7 and the bearing portions 7a and 5b. In order to bias the gap in the direction, two coil springs 12 are used, one for each of the two fitting portions, and a cam portion of the cam gear 9 for controlling the rotation of the traverse chassis 5. Since one coil spring 13 is used to urge the coil spring 9a, a total of three coil springs of two types are required.

For this reason, there is a problem that the cost increases due to an increase in the number of parts and the work process, and a space for installing three coil springs is also required.
There was a problem that it was difficult to save space.

Further, in the conventional optical disk device, the switch 18 for detecting the position of the cam gear 9 in the rotation direction is rotated by the switch cam portion 9b formed on the cam gear 9 about the arm fulcrum shaft 15 so that the inverted character is formed. Since the control is performed while engaging with one end of the die arm 16 and the switch 18 is operated at the other end of the arm 16, the cost increases due to an increase in the number of parts such as the arm 16 and the arm fulcrum shaft 15 and the work process. In addition to the above problem, there is also a problem that it is difficult to save space because an installation space for operating the arm 16 is required.

The present invention has been made in view of the above problems, and is achieved by appropriately setting the mounting position and angle of the coil spring of the tilt servo mechanism, and integrating the cam gear and the switch for switching the rotational position thereof. Cost reduction by reducing the number of parts and the assembly process,
The present invention provides an optical disk device that can save space.

[0022]

SUMMARY OF THE INVENTION A first invention of the present application is a traverse, which supports an optical pickup unit having a tilt sensor for detecting a radial tilt angle of a disc and is rotatable about a fulcrum shaft. An optical disk device comprising: a chassis; and a base chassis that rotatably supports the traverse chassis, and a cam that adjusts the tilt of the traverse chassis based on the detection output of the tilt sensor. Is provided in the direction of abutting against the cam, and at the same time, a unidirectional urging means is provided for urging in a direction of removing looseness of the gap generated in the fulcrum shaft.

A second invention of the present application is characterized in that a switch cam portion which comes into contact with a switch for detecting the rotational position of the cam is provided integrally with the cam.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of an optical disk device of the present invention will be described in detail below with reference to FIGS. Is omitted. Here, FIG. 1 is a plan view showing a tilt servo mechanism in the present embodiment, FIG. 2 is a side view of the same, FIG. 3 is a side view showing a cam gear and a switch structure (when the switch is turned on) in the present embodiment, and FIG. It is a side view showing a cam gear and a switch structure (when the switch is off) in the embodiment.

As shown in FIG. 1, the optical disk device of this embodiment has two coil springs 8 at two positions in the width direction of the traverse chassis 5 (the rotation axis direction of the traverse chassis 5).
Individually installed, both ends of each coil spring 8 are fixed and attached to the traverse chassis 5 and the base chassis 7.

By pulling the traverse chassis 5 diagonally downward to the right (direction of arrow A) shown in FIG. 2 by the two coil springs 8, the traverse chassis 5 is pulled.
And two fulcrum shafts 5 provided between the base chassis 7 and
c, 7b and the bearings 7a, 5b of the radial direction gaps generated at the two fitting portions in a specific direction (arrow A direction)
Can be urged.

Further, as shown in FIG. 2, a cam follower projecting downwardly at one end of the traverse chassis 5 is formed by the component force of the urging force of the two coil springs 8 in the downward direction (arrow B direction). 5a can be biased to the cam portion 9a below it.

In this state, the cam drive motor 10 is driven and controlled on the basis of the output of the angle detected by the tilt sensor 2 so as to follow the radial inclination angle of the disc 1 and thereby the inclination of the traverse chassis 5. It becomes possible to adjust.

As described above, in this embodiment, 2
Since the two coil springs 8 are attached at a position at a constant distance from the rotating shaft of the traverse chassis 5 and the attachment angles of the two coil springs 8 are inclined obliquely downward (direction of arrow A), As shown, at the attachment point of the traverse chassis 5 to which the left end of the coil spring 8 is attached, two component forces are generated in each of the vertically downward direction and the horizontal right direction.

As a result, in this embodiment, by using the two coil springs 8, it is possible to achieve the same effect as that of the above-mentioned conventional example using a total of three coil springs. In comparison, it is possible to reduce the number of parts and the assembly process.

Next, the tilt control operation of the traverse chassis 5 by the switch operation for rotating the cam gear 9 and detecting its position will be described with reference to FIGS. 3 and 4.
In this embodiment, the switch 14 is attached and fixed to the circuit board 17 provided on the lower side so as to sandwich the base chassis 7.

Here, the cam gear 9 having the cam portion 9a which is inclined stepwise in the vertical direction is rotationally driven by the cam drive motor 10 and abuts on the cam follower 5a of the traverse chassis 5 above the cam gear 9a to raise the height of the cam portion 9a. By operating the shaft in the vertical direction, the traverse chassis 5 can be rotated around the fulcrum shafts 5c and 7b to control the tilt in the vertical direction.

At this time, there is a portion of the cam portion 9a which is unnecessary for controlling the angle of the traverse chassis 5 within a certain range, and the rotation position of the cam gear 9 is set so as not to rotate the cam gear 9 to that portion. , Is electrically detected by the switch 14 that engages with the lower portion of the cam gear 9.

The switch 14 is attached to the lower portion of the cam gear 9, outputs a detection signal corresponding to the cam position, and transmits it to a control circuit section (not shown) via the circuit board 17. When the cam gear 9 rotates, the switch 14 has a switch cam portion 9b in which an inclined portion is formed on the lower surface of the cam gear 9.
Thus, the lever portion 14a inside the switch 14 is moved up and down to switch the switch 14 on and off.

When the switch is turned on as shown in FIG. 3, the cam portion 9a is formed.
Is a range where rotation is unnecessary, and the depth of the groove of the switch cam portion 9b becomes shallow, so that the lever portion 14a of the switch 14 is pushed down and the switch 14 is turned on. Normally, the switch 14 is in the off state, and when it enters this range by the rotation operation of the cam, the rotation operation direction of the cam portion 9a is reversed, and the switch 14 is controlled to return to the off position.

At that time, the position of the traverse chassis 5 is in the uppermost position when the cam portion 9a is in the switch 14 off state from the right rotation, and is in the most downward direction when the cam portion 9a is in the switch 14 off state from the left rotation. It will be located.

Further, as shown in FIG. 4, the rotation range of the cam portion 9a is the deep portion of the groove of the switch cam portion 9b, and the switch 14 is turned off without contacting the lever portion 14a of the switch 14.

As described above, in this embodiment, the cam gear 9 and the switch 14 for detecting the rotational position thereof are used.
Since the and are integrated, it is possible to reduce the number of parts and the driving space. Therefore, stable and highly reliable tilt servo control by the cam gear rotating mechanism can be performed.

The second embodiment of the optical disk device of the present invention will be described in detail with reference to FIGS. 5 and 6, but the same parts as those in the above-mentioned first embodiment are designated by the same reference numerals and the description thereof will be omitted. To do. Here, FIG. 5 is a plan view showing the tilt servo mechanism in the present embodiment, and FIG. 6 is a side view thereof.

In this embodiment, the coil spring 8 is provided at one end of the traverse chassis 5 on the cam side in the guide shaft 4 direction.
Is installed, and the other end of this coil spring 8 is attached and fixed to the base chassis 7.

With this one coil spring 8, a fulcrum shaft 5c between the traverse chassis 5 and the base chassis 7,
It is possible to urge a radial gap generated in the two fitting portions between 7b and its bearing portions 7a, 5b in a specific direction (arrow C direction = corresponding to clockwise direction).

Further, by tilting the coil spring 8 in the direction (direction of arrow D) in which the component force for urging the cam follower 5a of the traverse chassis 5 to the cam portion 9a is generated, the cam follower 5a of the traverse chassis 5 is at the same time. It can be biased to the lower cam portion 9a.

In this state, the cam drive motor 10 is driven and controlled based on the output of the angle detected by the tilt sensor 2 so that the traverse chassis 5 is tilted by following the radial tilt angle of the disk 1. It becomes possible to adjust.

As described above, in this embodiment, 1
At the attachment point of the traverse chassis 5 to which one end of the book spring 8 is attached, two component forces are generated in each of the vertically downward direction and the horizontally upward direction, as shown in FIGS. 5 and 6. .

As a result, in this embodiment, by using one coil spring 8, it is possible to achieve the same effect as the above-mentioned conventional example using a total of three coil springs. In comparison, it is possible to reduce the number of parts and the assembly process.

[0046]

Since the optical disk device of the present invention is configured as described above, the number of biasing means (springs) for biasing the traverse chassis can be reduced.
It is possible to reduce the number of parts and the assembly process.

Further, since the switch cam portion is formed integrally with the cam, it is possible to realize a highly reliable optical disk device capable of cost reduction and space saving with a minimum number of parts.

[Brief description of drawings]

FIG. 1 is a plan view showing a tilt servo mechanism in an optical disc device according to a first embodiment of the present invention.

FIG. 2 is a side view showing a tilt servo mechanism in the optical disc device according to the first embodiment of the present invention.

FIG. 3 is a side view (when the switch is turned on) showing a cam gear and a switch structure in the optical disc device according to the first embodiment of the present invention.

FIG. 4 is a side view (when the switch is off) showing a cam gear and a switch structure in the optical disc device according to the first embodiment of the present invention.

FIG. 5 is a plan view showing a tilt servo mechanism in an optical disc device according to a second embodiment of the present invention.

FIG. 6 is a side view showing a tilt servo mechanism in an optical disc device according to a second embodiment of the present invention.

FIG. 7 is a plan view showing a conventional optical disc device.

FIG. 8 is a side view showing a conventional optical disc device.

FIG. 9 is a plan view (when the switch is turned on) showing a cam gear and a switch structure used in a tilt servo mechanism of a conventional optical disc device.

FIG. 10 is a plan view (when the switch is off) showing a cam gear and a switch structure used in a tilt servo mechanism of a conventional optical disc apparatus.

[Explanation of symbols]

1 disc 2 Tilt sensor 3 Optical pickup unit 4 guide shaft 5 traverse chassis 5a Cam follower 5b Bearing part 5c fulcrum axis 6 Spindle motor 6a turntable 7 base chassis 7a Bearing part 7b fulcrum axis 8 coil springs 9 cam gear 9a cam part 9b Switch cam part 10 Cam drive motor 11 Reduction mechanism 14, 18 switch 14a lever part 15 arm axis 16 arms 17 circuit board

Claims (2)

(57) [Claims] 1. A traverse chassis that supports an optical pickup unit having a tilt sensor that detects a tilt angle of a disk in a radial direction and is rotatably provided around a fulcrum shaft, and rotatably supports the traverse chassis. At the same time, based on the detection output of the tilt sensor, in an optical disc device including a base chassis provided with a cam for adjusting the inclination of the traverse chassis, at the same time urging the traverse chassis in the direction of contacting the cam An optical disk device comprising a unidirectional urging means for urging in a direction for removing looseness of a gap generated on the fulcrum shaft. 2. The optical disk device according to claim 1, wherein a switch cam portion that comes into contact with a switch for detecting the rotational position of the cam is provided integrally with the cam. .