JPH0664876B2 - Information storage medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention drives an information storage medium such as an optical disk and records and reproduces information by using a laser beam or the like during its rotation. , Or to improvement of an information storage medium used in an information processing apparatus that performs information processing such as erasing.

(Prior Art) In recent years, an information processing device that uses an optical disk as a storage medium can significantly increase the amount of information that can be accommodated and has less noise than magnetic information processing devices that have been widely used conventionally. A very good and stable information reproduction state is obtained, the storage state is extremely stable because it is not easily affected by external factors, and information processing can be performed in a non-contact state to prevent damage to the storage medium and the information processing head. It is being used frequently because it has features such as no adverse effects.

In addition, along with this trend of increasing usage, it has recently been demanded to make the information processing apparatus of this kind, for example, an information recording / reproducing apparatus, as thin as possible, light in weight, and low in cost.

On the other hand, in the conventional device, as shown in FIGS. 6 and 7, the information storage medium (optical disk) a is replaced with the turntable b.
In the case of fixing the information storage medium (optical disk) a to the turntable b side via the clamper c, the information storage medium (optical disk) a is pressed.

6 shows a structure in which a pressing force is applied to a clamper c through a supporting means e provided with an urging body d such as a spring, and a structure shown in FIG. 7 is a magnet f to the clamper c. And a pressing force is applied to the clamper c by a magnetic attraction force generated between the clamper c and the turntable b made of a magnetic material.

However, in such a conventional device, not only the clamper c is required, but also a moving space necessary for moving the clamper c must be formed, and the clamper c is contacted and separated. A mechanism etc. is required. For this reason, the structure of this portion becomes complicated and large, which is not only a major obstacle to thinning, weight reduction and cost reduction, but also there is a problem that assembly and maintenance are troublesome.

Further, in the former type (FIG. 6), since the turntable b is always in a state of being subjected to a force, the turntable b and the rotating shaft g integrally with the turntable b must be made rigid.
Further, in the latter (FIG. 7), the holding force varies depending on the thickness of the information storage medium a, and when the information storage medium a is a relatively thick one such as two substrates h bonded together, it is sure to occur. There is a problem that it may not be able to be pinched.

Further, conventionally, the inner diameter portion i of the information storage medium a, that is,
The substrate h made of synthetic resin is directly fitted into the positioning part j formed on the turntable b side for positioning. Therefore, the diameter of the inner diameter portion i of the information storage medium a may change due to wear for a long time,
There is a serious problem in that the eccentricity between the center of the pre-groove (not shown) spirally formed on the substrate h at a pitch of 1.6 μm and the center of rotation becomes large, which adversely affects the recording / reproducing of information.

Therefore, in recent years, in order to solve this problem, as shown in FIG. 8, it is considered that the device can be mounted without using a clamper which causes obstacles such as thinning, weight reduction, and cost reduction. There is. This uses an information storage medium a in which a metal plate n having a central hole m is attached to a substrate h with an adhesive,
The information storage medium a is magnetically attracted to the turntable b side by the magnet f embedded in the turntable b.

However, since this structure has a structure in which the substrate h and the metal plate n having different thermal expansion coefficients are directly adhered by an adhesive, when they are affected by heat due to an external temperature change or the like, these thermal expansion coefficients are increased. Difference causes a force to be applied in the vicinity of the inner diameter of the substrate h, causing a slight distortion in the substrate h. The distortion of the substrate h is caused by the optical characteristics of the substrate h (especially birefringence).
However, there is a problem in that the recording / reproducing of information is adversely affected.

(Problems to be Solved by the Invention) As described above, it is possible to mount the device without using the clamper, which causes obstacles such as thinning, weight reduction, and cost reduction, and regardless of the thickness of the information storage medium. Even in the structure shown in FIG. 8 having the features, since the substrate h and the metal plate n having different thermal expansion coefficients are directly adhered to each other with an adhesive, the influence of heat due to an external temperature change or the like is exerted. When received, a slight distortion occurs in the substrate h due to the difference in the coefficient of thermal expansion, which affects the optical characteristics (particularly the birefringence index) of the substrate h, and particularly has a great adverse effect on the recording / reproducing of information. There is.

The present invention has been made based on the above circumstances, and an object of the present invention is that it can be easily and surely mounted without using a clamper which is an obstacle to cost reduction and the like, and that the distortion of the substrate due to the thermal influence can be prevented. An object of the present invention is to provide an information storage medium capable of preventing occurrence and capable of stable information processing.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention is mounted on a turntable that houses a magnetic circuit forming member that forms a magnetic circuit in a recess and is rotationally driven. In the information storage medium, the substrate and the attracted member that is magnetically attracted by the magnetic circuit forming member to the turntable side at the center of rotation of the substrate, and the attracted member is at the center of rotation. And a magnetic member movably attached to this centering member.

(Effect) That is, according to the present invention, the information storage medium can be magnetically attached to the turntable by the above-described configuration, which makes it possible to reduce the thickness, weight, and cost of the device conventionally required. It is possible to mount the clamper without the need for a clamper that may be a hindrance. Further, since the attracted member attached to the center of the substrate is composed of the centering member and the magnetic member attached to the centering member, distortion of the substrate due to the difference in thermal expansion coefficient between the substrate and the magnetic member is prevented. It can be prevented and stable information processing becomes possible.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. In FIG. 1, reference numeral 1 denotes an information storage medium (hereinafter referred to as a disc) housed in a cartridge 2, and the disc 1 is inserted together with the cartridge 2 into a medium insertion / ejection opening formed in a main body (not shown) of an information processing apparatus. It has become so.

The disc 1 inserted together with the cartridge 2 is automatically taken into a predetermined position and in a horizontal state by a medium taking-in / mounting mechanism (not shown), and at this time, the cartridge 2 exposes a part of the disc 1. The center of rotation is open. After that, the cartridge 2 is displaced in the surface direction, and the disc 1 is automatically mounted on the turntable 4 of the medium driving means 3.

The disc 1 comprises two substrates 6 each having an information recording layer 5,
6 is adhered with an inner spacer 7 and an outer spacer (not shown) sandwiched so that the information recording layers 5 and 5 are on the inner side, and attracted members 8 and 8 that are magnetically attracted to both surfaces of the inner diameter portion. Is attached.

The substrates 6, 6 are made of injection-molded transparent plastic plates, and are adhered to the inner spacer 7 and the outer spacer via an ultraviolet curable adhesive.

As shown in FIGS. 3 and 4, the attracted member 8 includes a centering member 20 and a magnetic member 21 attached to the centering member 20.

The centering member 20 is formed of a synthetic resin material into a disc shape, has a center hole 10 in the center for fitting with the centering portion 9a of the rotating shaft 9 of the medium driving means 3, and has a substrate 6 on the lower surface side. The inner diameter portion 6a has a convex portion 20a into which the outer diameter portion is fitted.

Then, the outer diameter portion of the convex portion 20a is fitted to the inner diameter portion 6a of the substrate 6 to perform positioning with respect to the substrate 6, and in this state, the substrates 6, 6 are adversely affected. There is no adhesive, such as an epoxy-based adhesive.

The substrate 6 has an inner diameter portion 6a which is a central hole formed at the same time so as to shorten the processing time.
As shown in the figure, a step 6b is formed in the inner diameter portion of the substrate 6.
This occurs because the resin in the gate portion is peeled off when the punch cuts the resin during the molding process, and the step portion 6b is projected on the surface opposite to the outer surface of the substrate 6 so that the inner diameter becomes small.

This step portion 6b has a slight amount, but the surface is not smooth and the accuracy is poor.

As described above, since the inner surface of the substrate 6 is more accurate on the outer side surface of the substrate 6, the height dimension h ₁ of the convex portion 20a of the centering member 20 is set to the substrate 6 as shown in FIG. The thickness of the centering member 20 is set to be smaller than the thickness h ₂ so that only the accurate portion is
20a is fitted to maintain good positional accuracy with little eccentricity.

The inner diameter portion 6a of the substrate 6 is precisely formed coaxially with a recording / reproducing pregroup (not shown) formed on the substrate 6, and the outer diameter portion of the convex portion 20a of the centering member 20 is formed. The center hole 10 of the centering member 20 is processed coaxially with high precision, so that the center of the pregroup and the rotation axis of the rotation shaft 9 can be aligned. And a decrease in recording / reproducing accuracy caused by the eccentricity,
It is also possible to prevent problems such as increase in access time.

Further, the magnetic member 21 is formed from a metal plate into a disc shape having a through hole 21a in the central portion, and is fitted into the annular recess 20b formed on the upper surface of the centering member 20 to be slightly larger than this. It is mounted so as to be in a retracted state, and its movement in a direction perpendicular to the surface of the substrate 6 is restrained by a mounting means 22 described later, so that it can be slightly moved in a direction parallel to the surface of the substrate 6.

As shown in FIGS. 4 and 5, the attachment means 22 includes three locked portions 23 formed on the centering member 20 so as to be positioned at the same center circle at equal intervals, and these locked portions 23. Stop 23 ...
And a locking claw 24 formed in the magnetic member 21 so as to have the same positional relationship as the locked portion 23.

The locked portion 23 has a claw insertion hole 23a formed to have a size capable of inserting the locking claw 24 and a slit portion 23b formed in a state of communicating with the claw insertion hole 23a and a slit portion 23b.
A return prevention protrusion 23c is formed on the lower surface of the one side edge.

On the other hand, the locking claw 24 is a cut-and-raised tongue piece 21 bent in an L shape.
It is formed by a.

For attachment, first, the locking claws 24 formed on the magnetic member 21 are inserted into the claw insertion holes 23a of the centering member 20, and then the magnetic member 21 is set in the state shown in FIG. The horizontal portion 24b is locked to the lower surface of one side edge of the slit portion 23b by pivoting in the direction so that the vertical portion 24a of the locking claw 24 is interposed in the slit portion 23b. At this time, the horizontal portion 24b of the locking claw 24 is elastically deformed and the slit portion 2
The return prevention protrusion 23c formed on the lower surface of one side of 3b is overridden, and even if the return protrusion 23c tries to return in the direction of the claw insertion hole 23a, the prevention protrusion 23c does not interfere and return.

In this way, the magnetic member attached to the centering member 20.
21 is locked parallel to the surface of the substrate 6 by locking the horizontal portion 24b of each of the locking claws 24 ... In the direction, it can be slightly moved by a gap formed between the slit portion 23b and the vertical portion 24a.

The medium driving means 3 is an outer rotor type brushless DC motor having a motor shaft as the rotating shaft 9.
11 and a turntable 4 attached to a rotary shaft 9 of the motor 11.

The turntable 4 is made of a non-magnetic metal material, and a recess 4a is formed on the upper surface side thereof. A magnetic circuit forming member 14 including a magnet 12 and a yoke 13 for magnetically attracting the attracted member 8 of the information storage medium 1 is accommodated in the recess 4a. This is to fully exert the force for mounting the disk 1 on the turntable 4 and to prevent the leakage of the magnetic field to the outside.

Further, the attracted member 8 is formed such that the outer diameter D ₁ thereof is smaller than the inner diameter D _{2 of the} recess 4a formed to accommodate the magnetic circuit forming member 14 on the upper surface of the turntable 4. As shown in the drawing, when the disc 1 is mounted in a state where it is fitted into the positioning portion 9a of the rotary shaft 9 of the central hole 10 of the member to be attracted 8, the member to be attracted 8 is housed in the recess 4a. Has become. The substrate 6 having the information recording layer 5 of the disc 1 is brought into direct contact with the annular table surface 4b on the outer side of the turntable 4.

Then, the substrate 6 having the information recording layer 5 of the disc 1 is surely pressed against the turntable 4 so that the shake in the direction perpendicular to the surface of the substrate 6 is minimized, whereby stable information recording is achieved. It has a structure that allows reproduction.

If the attracted member 8 and the table surface of the turntable 4
In the case where the sucked member 8 is in contact with the sucked member 8, the surface of the sucked member 8 and the surface of the substrate 6 must be very accurately parallel to each other because the swing of the disk 1 becomes large. Since the wall thickness and the thickness of the adhesive must be made uniform, this is an extremely difficult work.

On the other hand, the length of the centering portion 9a of the rotary shaft 9 of the medium driving means 3 is limited to the length that fits only with the central hole 10 of the attracted member 8 on the turntable 4 side, and the length of the two covered portions is reduced. Suction member 8,
It is configured so that the coaxiality of the eight central holes 10 and 10 does not matter so much.

The inner diameters of the two substrates 6 and 6 and the two members to be attracted
Making the center holes 10, 10 of 8, 8 coaxial is a difficult task, and if the length of the centering portion 9a is longer than necessary, it will take a long time to be mounted on the turntable 4. Moreover, it becomes a problem from the viewpoint of wear and the like.

Further, since the magnetic circuit is formed in the concave portion 4a of the turntable 4, magnetic leakage to the outside is minimized, so that magnetic powder such as iron powder adheres to the rotating shaft 9. It is possible to prevent the sucked member 8 from not fitting properly.

A proper gap G is formed between the magnet 12 and the yoke 13 housed in the recess 4a of the turntable 4 and the attracted member 8 as shown in FIG. 6 and the table surface 4b are in direct contact with each other. Further, the gap G surely transmits the driving force of the turntable 4 to the disc 1 and, moreover, the disc 1
This is because the disc 1 is mounted with an appropriate suction force (mounting force) with which the disc 1 can be easily detached from the turntable 4 simply by raising the cartridge 2 accommodating therein.

Reference numeral 15 shown in FIGS. 1 and 2 is a motor mounting frame of the medium driving means 3, and 16 is a control board for controlling the driving of the motor 11.

Reference numeral 17 shown in FIG. 2 is a head that moves in the radial direction of the disk 1 by a head moving means such as a linear motor (not shown), and is a lower surface side substrate of the information storage medium 1 that is mounted and driven by the medium driving means 3. Information processing such as recording or reproducing is performed on the information recording layer 5 formed in 6.

Then, the disk 1 having the above-described configuration, which includes the substrate 6 and the attracted member 8 attached to the central portion of the substrate 6,
Since it becomes possible to magnetically attach the magnetic circuit forming member 14 to the turntable 4 side, a clamper which obstructs the conventional thinning, weight reduction and cost reduction of the device is used. Without, again, disk 1
It can be installed regardless of the thickness. Further, the attracted member 8 attached to the central portion of the substrate 6, a centering member 20 having a central hole 10 serving as a center of rotation in the central portion and a convex portion 20a that fits with the inner diameter portion 6a of the substrate 6, This centering member 2
Since it is composed of the magnetic member 21 attached to the substrate 0, the substrate 6
The influence of the difference in thermal expansion coefficient between the magnetic member 21 and the magnetic member 21 can be absorbed at this portion, and stable information processing can be performed without causing distortion in the substrate 6 as in the conventional case.

In the above-described embodiment, the yoke 13 of the magnetic circuit forming member 14 housed in the recess 4a of the turntable 4 for magnetically attracting the information storage medium of the present invention is erected on both the inner diameter portion and the outer diameter portion. Although the structure having the upper portions 13a and 13b has been described, the present invention is not limited to this, and may have a rising portion only in the inner diameter portion, or may have a rising portion only in the outer diameter portion. It may be one that has been made.

Further, although the material of the centering member 20 is synthetic resin, it is not limited to this. That is, since a material having a coefficient of thermal expansion similar to that of the material of the substrate 6 may be used, it should be bound according to the material of the substrate 6. For example, if the substrate 6 is made of glass, the centering member is used. 20 may be glass, ceramics, or the like.

In addition, it goes without saying that the present invention can be variously modified and implemented without departing from the spirit of the present invention.

[Effects of the Invention] As described above, the present invention is mounted on a turntable that houses a magnetic circuit forming member that forms a magnetic circuit in a recess, and is driven to rotate. An information storage medium having a magnetically attracted member attached to a side thereof, wherein the attracted member has a central hole serving as a center of rotation in a central portion and is fitted with an inner diameter portion of the substrate. A centering member and a magnetic member attached to the centering member are provided. Therefore, since the information storage medium can be magnetically attached to the turntable by suction, the information storage medium can be attached without the need for a clamper, which is an obstacle to the thinning, weight reduction, and cost reduction of the conventional device. It becomes possible to do.
Further, since the attracted member attached to the central portion of the substrate is composed of the centering member and the magnetic material attached to the centering member, distortion of the substrate due to the difference in thermal expansion coefficient between the substrate and the magnetic member is prevented. The effect is that it can be prevented and stable information processing can be performed.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention.
FIG. 2 is a schematic sectional view showing a partially cross-section of an information storage medium in an unmounted state, FIG. 2 is a schematic sectional view showing a partially sectional view of a state in which an information storage medium is mounted, and FIG. FIG. 4 is an enlarged view of a main part, FIG. 4 is a plan view of a member to be attracted, which is a main part, and FIG. 5 is an exploded perspective view showing a mounting means of a centering member and a magnetic member that constitute the member to be attracted. 8 are schematic cross-sectional views showing the mounting states of the conventional example and the prior art example which are different from each other. 1 ... Information storage medium (disk), 4 ... Turntable, 4a ... Recess, 8 ... Member to be attracted, 10 ... Center hole, 14
...... Magnetic circuit forming member, 20 ...... Centering member, 21 ...... Magnetic member, 22 ...... Mounting means, 23 ...... Engaged part, 24 ...... Locking claw.

Claims (6)

[Claims] 1. An information storage medium, which is mounted on a turntable that accommodates a magnetic circuit forming member for forming a magnetic circuit in a recess and is rotationally driven, comprising: a substrate; and the magnetic field on the turntable side at the center of rotation of the substrate. And a centering member that has a center hole that serves as a center of rotation and that fits into the inner diameter portion of the substrate. An information storage medium comprising a magnetic member movably attached to a centering member. 2. The information storage medium according to claim 1, wherein an outer diameter of the member to be attracted is set smaller than an inner diameter of a recess provided in the turntable. 3. The magnetic member is attached to the centering member via an attaching means so that the movement of the magnetic member in a direction perpendicular to the surface of the substrate is restricted and the magnetic member can be slightly moved in a direction parallel to the surface of the substrate. The information storage medium according to claim 1, wherein the information storage medium is provided. 4. The mounting means comprises a locked portion formed on a centering member and a locking claw formed on a magnetic member for engaging the locked portion. Range third
The information storage medium described in the item. 5. The information storage medium according to claim 1, wherein the centering member has a convex portion that fits into the inner diameter portion of the substrate. 6. The information according to claim 5, wherein the height dimension of the convex portion of the portion of the centering member that fits with the inner diameter portion of the substrate is set smaller than the thickness of the substrate. Storage medium.