JPS63146278A - Disk device - Google Patents

Abstract

PURPOSE:To always ensure fixed angle between the direction of a head and the direction of a recording train (track) of a disk, by providing a circular turntable to mount the disk and a rail which can be turned centering on a prescribed fulcrum. CONSTITUTION:The joint part between an optical head 104 and an arm 107 is turned in a circular arc around a head drive motor 106 in accordance with rotation of the ram 107. In this case, said joint part is set so as to be movable round a vertical shaft and therefore the direction of the head center line is never turned in response to the rotation of the arm 107. The angle of the joint part between the head 104 and the arm 107 is automatically decided so that the head center line is always directed to the center direction of a disk. As a result, the head 104 is always kept at a fixed angle to the track direction of the disk and therefore the correct control signal are always detected.

Description

[Detailed description of the invention] (Purpose of the invention) (Industrial application field) The present invention relates to a disk device.

(Prior art) Information is recorded along spiral or concentric tracks on the surface of a conventional disk on which information has been recorded, and the information signal is optically reproduced using a light beam such as a laser beam. Attempts have been made to do so.

In recent years, there has been active research into devices that allow a device user to record information on an optical disk, or devices that allow recorded information to be erased and rewritten, and many publications have been published at academic conferences and in literature. Since these optical disk devices can record large amounts of information at high density, they are expected to find a wide range of applications. For this reason, a lot of research has been conducted on various development issues such as improving reliability, increasing capacity, and increasing speed, but miniaturization of equipment is an important issue when applying to relatively small-scale systems. becomes. Especially regarding the mechanism of the device,
It is important to reduce the size of the part responsible for moving the optical head.

Code players and magnetic disk devices are known as conventional disk-type recording devices, but the systems that are often used for the pickup and magnetic head feeding mechanism in these devices include There are two types: a linear type that moves the robot linearly along a path, and a rotary type that moves the robot along an arcuate trajectory using an arm movable around one point. These methods are also used to move the optical head of an optical disk device. In particular, a method of moving along an arcuate trajectory is considered to be suitable for downsizing because it facilitates efficient use of space.

However, in the method of moving in an arc, the optical head also rotates as the arm rotates, so the disadvantage is that the direction of the optical head cannot always be maintained at a constant angle with respect to the direction of the disk track. was there.

FIG. 5 shows how the optical head moves in a conventional device that employs a rotary type. Figure 15 (2), (i, (
In C), the optical disc 1501 is fixed by a turntable 1503 attached to a disc motor 1502. The optical head 1504 has an objective lens 15
05 to focus the laser beam onto the disk. The optical head 1504 is fixed to an arm 1507 attached to a head drive motor 1506.
6 to move the access position. Figures 15(c) and 15(c) show the states when accessing tracks on the outer circumference, middle tracks, and inner tracks of the disk, respectively.
(c).

Shown in (C). As is clear from the figure, even if the center line 1508 of the optical head is adjusted so that it coincides with the radial direction of the disk when accessing the middle track of the disk, the track on the outer periphery is not accessed. When accessing the inner track, the center line shifts clockwise in the figure, and when accessing the inner track, the center line shifts counterclockwise. This phenomenon is particularly noticeable when the arm is shortened to miniaturize the device. In an optical disk device, the emitted light beam is narrowed down to about the wavelength of the light. In order to focus this light beam on the track correctly, we are equipped with means to detect focusing errors and tracking errors, and by controlling the position of the focus point of the light beam using the signals obtained by these means, we can accurately track the light beam. However, when the direction of the optical head is out of alignment with the direction of the tracks on the disk, it becomes difficult for these error detection means to accurately detect the error. Therefore, it was difficult to realize a highly reliable device using a method of moving in an arc.

Therefore, in an attempt to maintain a constant angle with respect to such tracks on the inner and outer tracks of the disk, a device as shown in FIG. ) are disclosed. This device has a link lever 1602 that can rotate within a predetermined angular range around a fulcrum, and a slider 1603 that is connected and pivoted to the moving end of this lever and supports a pickup optical system 1605. The disc 1604 is characterized in that the center of rotation of the video disc 1604 is used as a guide 1601 so that the disc 1604 can be moved freely in the radial direction.

However, in this method, even if the guide 1601 is composed of rollers, there is a spindle motor (not shown) at the center of rotation of the disk 1604, so it is necessary to secure this space, which makes it difficult to achieve high precision and stability. This spindle motor (the axis of) that needs to be rotated
Providing the guide 1601 on the slider 160
It is obvious that various problems will occur as the drive speed increases.

(Problem to be solved by the invention) In other words, a drive mechanism is realized in which the head moves in an arc shape and the direction of the head is always at a constant angle with respect to the direction of the recording rows (travels) on the disk. However, it has traditionally been a technical challenge to realize a stable disk device that can utilize space effectively.

Therefore, in view of this conventional technical problem, the present invention realizes a drive mechanism in which the direction of the head is always at a constant angle with respect to the direction of the recording row on the disk, and it is possible to track the recording row by this head. The object of the present invention is to provide a disk device that is compact, highly reliable, and extremely easy to use.

(Structure of the Invention) (Means for Solving the Problems) This invention provides a circular turntable on which a disk is placed, a means for rotationally driving the turntable, and a turntable placed on the turntable. A head for reproducing information recorded on a disk, a rail that supports this head and is rotatable around a predetermined fulcrum,
This disk device is characterized by comprising a rotary drive motor for driving the head along the rail, and an arm for transmitting the driving force of the rotary drive motor to the head.

(Function) The head is restricted to move along an arc-shaped locus drawn by the tip of the arm that transmits the driving force of the rotary drive motor to drive the head, and the head is moved by a rail that can rotate around a fulcrum. is restricted to a constant angle with respect to this rail.

At this time, since the center of rotation of the disk, the position of the head, and the fulcrum of the rail are equidistant from the center of rotation of the arm, the angle of the head in the direction from the head to the center of the disk is also constant, and the angle between the head and the track is always constant. Can maintain a constant angle.

(Example) O first embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a mechanism for driving a disk and moving an optical head in an apparatus according to an embodiment of the present invention. In FIG. 1 (C), ■, (C), the optical disc 10
1 shows a part of its outer shape with a dotted line. The optical disc is fixed by a turntable 103 attached to a disc motor 102.

The optical head 104 uses an objective lens 105 to focus the laser beam onto the disk. The optical head 104 is connected to an arm 107 attached to a head drive motor 106, and is moved to an access position by being driven by the head drive motor 10B. Here, the connecting portion between the optical head H) 4 and the arm 107 is attached by a pin 108 so as to be rotatable around an axis perpendicular to the plane of the drawing. On the other hand, this optical head 104 is attached to a rail 109 extending in the radial direction of the disk, and is movable along the rail 109 while always aligning the center line of the optical head with the direction of the rail 109. In addition, this rail 109 is fixed to a ring 110 that is attached to the disc motor 102 and is rotatable around the disc motor 102.
It is rotatable around the disk motor 102 together with the ring 110 .

Figure 1 (4) shows what happens when accessing tracks on the outer periphery, when accessing tracks in the middle, and when accessing tracks on the inner periphery of the disk, respectively.
a. Shown in (C). As is clear from the figure, as the arm 107 rotates, the optical head 104 and the arm 1
The connecting portion between the optical head 104 and the arm 107 rotates in an arc around the head drive motor 106, but the connecting portion between the optical head 104 and the arm 107 is movable around an axis perpendicular to the plane of the figure. Since it is attached so that it does not rotate with the rotation of the arm. optical head 10
4 and the arm 107 is automatically determined so that the direction of the center line of the head always points toward the center of the disk. Therefore, the angle of the optical head with respect to the direction of the track on the disk is always constant, making it possible to always detect a correct control signal.

A diagram of this principle is shown in FIG. Center the optical disc at A
1 The center of the head drive motor is 81 The center of the objective lens is C
The fulcrum of the rule is E. The above reason can also be seen from this figure.

FIG. 2 shows the mechanical part of the apparatus of the above embodiment viewed from the side. In FIG. 2, parts corresponding to those in FIG. 1 are indicated by the same numbers, and explanations thereof will be omitted. The load on the head drive motor can be reduced by attaching the rail to the head so that it can move smoothly, for example by using a bearing 211 as shown in the figure.

In the embodiment described above, the rail for determining the direction of the optical head was in the form of a straight line passing through the center of the disk. However, the shape of the rail is not limited to a straight line. For example, it may be a rail 401 with a gentle curve as shown in FIG. Fourth
In the figure, parts corresponding to those in FIG. 1 are designated by the same numbers, and their explanation will be omitted. The operation is the same as in the above embodiment, but the rail has a curvature, and the attachment of the arm 107 and the optical head 104 approaches the arc drawn by the part, so when the head moves, the rail does not align with the central axis of the disk. The angle of rotation around the center becomes smaller. Therefore, the load on the head drive motor is reduced, making it possible to perform high-speed access. The shape of the rail is such that the center line of the head coincides with the radial direction of the disk no matter where the head moves on the rail. The specific shape of the rail depends on the method of mounting the head, etc.

FIG. 5 shows the optical head 104 and rail 4 in this embodiment.
01 installation shows the part viewed from below. The rail 401, shown in dotted lines in the figure, is connected to the rotating ring I,n.

(2), 501, 502, and 503 are sandwiched and fixed.

In addition, the rail has grooves dug on the side, and rotating rings I, n
, III are partially fitted into the groove, so they do not shift vertically. The rotating rings I, ff are mounted using rotating bearings so as to be rotatable around pins I, II, 504°505 fixed to the head. Also, the rotating ring III 503 is also connected to the pin III.
The pin 506 is attached so as to be able to rotate around the optical head 10B using a rotation bearing, and the pin 506 is attached to press the rotation ring I [I 503 against the rail 401 by a leaf spring 507, and when the optical head 104 moves, I try not to shake it. .

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, although a bearing or rotational bearing is used to attach the optical head to the rail, a structure in which the optical head and the rail can be slid on the rail may also be used using a resin component with a small coefficient of friction. Furthermore, although the arm that transmits force to the optical head is directly driven by the head drive motor, there is no problem even if some other driving force transmission means is interposed therebetween.

OSecond Embodiment In the above embodiment, the rail is not directly supported by the disk motor, which causes some problems in the stability of the motor.

Therefore, the optical head was made movable along a rail fixed in the radial direction of the disk, and the attachment part to the optical head was modified so that the actual length of the arm that drives the optical head was variable. It is conceivable that this could be achieved.

FIG. 3 shows a second embodiment. In FIG. 3, a part of the outer shape of the optical disc 101 is shown by dotted lines. The optical disc is fixed by a turntable 103 attached to a disc motor 102. optical head 1
04 is movable along rails 105 fixed in the radial direction of the disk. The optical head 104 is attached to an arm 107 attached to a head drive motor 108, and is moved to an access position by being driven by the head drive motor 106. In the mounting portion, a pin 308 fixed to the optical head is movable along a long and narrow guide hole 309 formed in the arm 107, and as the optical head moves, the contact position of the pin 308 with the arm 107 also moves.

However, since the driving force is transmitted in a direction substantially perpendicular to the direction of effective expansion and contraction of the arm, there remain drawbacks such as slight play or loss of driving force at the connecting portion.

0 Third Example Next, a third example will be described. This embodiment completely solves the above problems.

FIG. 6 is a diagram showing a mechanism related to optical head movement in an apparatus according to a third embodiment of the present invention. In FIG. 3, a part of the outer shape of the optical disc 101 is shown by dotted lines. The optical disc 101 is driven by a disc motor 10.
It is fixed by a turntable 103 attached to 2 and rotates around 601A. optical head 10
4 focuses the laser beam onto the disk using an objective lens 105. Reference numeral 107 denotes an arm, one end of which is connected to the optical head drive motor 106, and is driven to rotate around its rotation center 602B.

The other end is connected to the optical head 104 via the pin 10B, and is rotatable around the center 603D of the pin 10B. On the other hand, the rail 109 is attached via a pin 604 so as to be rotatable around its center 11605E. Optical head 104 is mounted so as to be movable along rails 109. To ensure smooth movement along the rail 109, bearings are used at this attachment point. This prevents loss of driving force due to friction.

This principle is illustrated using FIG. 12: the rotation center A of the optical disk, the rotation center B1 of the arm, and the rotation center E of the rail.
This is an example where the lines are lined up in a straight line. In this case, since the center position of the pin is always on the circumference whose diameter is the line segment connecting the rotation center A of the optical disk and the rotation center E of the rail, the direction from the center position of the pin toward the rotation center A of the disk is perpendicular to the rail. Therefore, no matter what position the optical head is moved by the optical head drive motor, the optical head can always maintain an orientation parallel to the direction of the track on the disk. As in the device according to this embodiment, the rotation center A of the optical disk and the rotation center B1 of the arm are
In a system in which the rotation centers E of the rails are aligned in a straight line, the direction of the rails is always parallel to the direction of the track, which has the inherent effect that the optical head has a shape that is easy to design.

Fourth Embodiment FIG. 7 is a diagram showing a mechanism related to optical head movement in an apparatus according to a fourth embodiment of the present invention. In FIG. 4, parts corresponding to those in the third embodiment of the present invention are designated by the same numbers, and their explanation will be omitted. Further, this principle is shown in FIG. 13 and will be described with reference to it.

This example is an embodiment in which the rotation center 601A of the optical disk, the rotation center 602B of the arm, and the rotation center 605E of the rail 109 are not aligned in a straight line. Even in this case, the center position 6030 of the pin 108 is always the rotation center 601A of the optical disk and the rotation center 605 of the rail 109.
It is on the same circumference as E and is centered on the rotation center 602B of the arm. Therefore, the direction from the center position 603D of the pin 10B to the rotation center 601A of the disk is the rail 10.
The direction is always the same angle with respect to 9. As a result, no matter what position the optical head is moved by the optical head drive motor, the optical head can always maintain an orientation parallel to the orientation of the tracks on the disk. As in the device according to the fourth embodiment, the rotation center 601A of the optical disk.

In systems where the arm rotation center 602B and the rail 109 rotation center 605E are not aligned, there is an inherent advantage that the arm, rail, and motor fit within a relatively small area.

Fifth Embodiment FIG. 8 is a diagram showing a mechanism related to optical head movement in an apparatus according to a fifth embodiment of the present invention. In FIG. 8, parts corresponding to those in the third embodiment of the present invention are designated by the same numbers, and explanations thereof will be omitted. A similar principle diagram is shown in FIG. 14.

This example is an embodiment in which the rotation center 605E of the rail 109 is within the movable range of the optical head. Even in this case, the center position 603D of the pin 108 is always on the same circumference around the arm rotation center 602B as the optical disk rotation center 601A and the rail rotation center 605E. Therefore, the direction from the center position 6030 of the pin 108 to the rotation center 601A of the disk is always at the same angle with respect to the rail. As a result, no matter what position the optical head is moved by the optical head drive motor, the optical head can always maintain an orientation parallel to the orientation of the tracks on the disk. In a system in which the rotation center 605G of the rail is within the movable range of the optical head, such as the device according to the fifth embodiment, the moment of inertia of the rail with respect to the rail rotation center becomes small, and the optical head is driven There is a unique effect that the driving force of the motor 106 works effectively.

Sixth Embodiment FIG. 9 is a diagram showing a mechanism related to optical head movement in an apparatus according to a sixth embodiment of the present invention. In the third to fifth embodiments, a so-called optical disk device in which a laser beam is focused onto a disk surface by an objective lens was shown, but this example shows an embodiment of the present invention in an apparatus for inspecting a disk.

vinegar. In FIG. 9, parts corresponding to those in the third embodiment of the present invention are designated by the same numbers, and explanations thereof will be omitted.

901 is an exit hole, and 902 is an entrance hole.

The light emitted from the exit hole 901 is reflected or scattered by the disk, then enters the entrance hole 902, and is detected by a detector. With this configuration, it is possible to evaluate the flatness of the disk or the accuracy of the spacing and depth of the guide grooves formed on the surface. Even in such an apparatus, the direction of light irradiation with respect to the center of the disk must be constant for highly accurate measurement, and the present invention can be effectively used.

In this example, the shape of the rail is different from the previous example, but the rail is linear in the part corresponding to the movable range of the optical head, and the connection point between the optical head and the arm and the rotation center of the rail are connected to this extension line. are located equal distances apart on the same side. Therefore, the way the optical head moves is geometrically equivalent to moving along a straight rail connecting the connection point between the optical head and the arm and the rotation center of the rail.

When non-linear rails are used in this way, there is a degree of freedom in the design of the rail shape, which makes it easier to use the space inside the equipment effectively, such as by arranging circuits in empty spaces. There is an effect.

Seventh Embodiment FIG. 10 is a diagram showing a mechanism related to optical head movement in an apparatus according to a seventh embodiment of the present invention. 7th
In the figures, parts corresponding to those in the third embodiment of the present invention are designated by the same numbers, and explanations thereof will be omitted.

In this example, the shape of the rail is curved even in the movable portion of the optical head. The shape of the second arm may be determined so that the direction from the connection point between the optical head and the arm toward the rotation center of the rail is always constant with respect to the optical head. This shape depends on the width of the arm and the mounting position of the optical head, but for example, in polar coordinates, a curve represented by r-Axexp (Bθ) (A and B are constants) can be drawn at any point on the curve. The direction toward the origin and the tangential direction are always at a constant angle. This can be achieved by using such a curve. Similarly to the case of the sixth embodiment, when a curved rail is used as in this example, there is a unique effect that it becomes easier to use the space within the device effectively.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, although bearings were used to attach the optical head to the rails, a structure in which the optical head slides on the rails may be constructed using resin parts with a small coefficient of friction.

Furthermore, although the arm that transmits force to the optical head is directly driven by the head drive motor, there is no problem even if some other driving force transmission means is interposed therebetween. As described above, any modifications can be made without departing from the spirit of the invention, and such modifications are included in the invention.

Furthermore, although the explanation has been given in the context of optical discs, it is clear that the invention is not limited to this and can be applied to record players and the like.

〔Effect of the invention〕

Since the present invention has many degrees of freedom in how to set the center position of the arm, it can be easily implemented even within conditions that are limited by other elements in the device configuration. According to the present invention, even in the method of moving the optical head in an arc shape,
A drive mechanism in which the direction of the optical head is always at a constant angle with respect to the direction of the recording rows on the disk can be realized with a simple configuration, and it is possible to accurately track the recording rows with a light beam. As a result, it is possible to provide an optical disk device that is compact, highly reliable, and extremely easy to use.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a side view of the device of the first embodiment, and FIGS. FIG. 5 is a view showing the attachment of the optical head and rail in FIG. 4 as viewed from below, and FIGS.
11 is a diagram showing the principle of the first embodiment, and FIGS. 12 to 14 are diagrams showing the fourth to sixth embodiments.
FIG. 15 and FIG. 16 are diagrams showing a conventional example. 101... Optical disk 102... Motor 1
03...Turntable 104...Optical head 105...Objective lens 106...Head drive motor 107...Arm 108...Bin 109...Rail 110...Ring agent Patent attorney Rules Ken Yudo Chika Kikuo Takehana Figure 1 Figure l Figure tab - tFAEiha 4 Figure 2 Figure 3 Figure 4 Figure 5 Figure 11 Figure 12 Figure 13 Figure 15 1ω4 @16 Figure

Claims (5)

[Claims] (1) A circular turntable on which a disk is placed; a means for rotationally driving this turntable; a head for reproducing information recorded on a disk placed on the turntable; A rail that supports the head and is rotatable about a predetermined fulcrum; a rotary drive motor for driving the head along the rail; and a rotary drive motor for transmitting the driving force of the rotary drive motor to the head. A disk device comprising an arm. (2) The disk device according to claim 1, wherein the rail is arranged so that the fulcrum position is at the center of the turntable. (3) The disk device according to claim 1, wherein the center of the turntable, the center of rotation of the rotary drive motor, and the fulcrum position of the rail are arranged on the same straight line. (4) The disk device according to claim 1, wherein the center of the turntable, the center of rotation of the rotary drive motor, and the supporting point of the rail are arranged at vertices of an equilateral triangle. (5) The disk device according to claim 1, wherein the disk device is arranged such that the center of the turntable and the fulcrum of the rail are located on a circumference centered on the rotation center of the rotary drive motor. .