JP5524545B2 - Flexible disk system and method for manufacturing flexible disk - Google Patents

Description

  The present invention provides a recording / reproducing apparatus for performing recording and / or reproducing processing on a flexible disk having flexibility, a rotating mechanism for fixing and rotating the flexible disk on a rotating shaft, and recording and / or recording on the flexible disk. Alternatively, the present invention relates to a flexible disk system having means for performing a reproduction process and a method for manufacturing a flexible disk including flexibility as a component.

  In recent years, there has been a demand for information recording media to record large volumes of digital data, such as the start of digitization in television broadcasting. For example, in the field of optical discs, one of the basic methods for increasing the density is to reduce the diameter of the light spot focused on the optical disc for recording and reproduction (hereinafter referred to as optical disc). As a representative example, the disk-shaped medium used in the recording / reproducing apparatus targeted by the present invention is intended to be limited to all disk-shaped media such as phase change memory, magneto-optical memory, and hologram memory. is not).

  In a recording / reproducing apparatus, in order to perform high-density recording and reproduction by narrowing down the laser beam, it is important that the disc surface shake during the disc rotation, that is, the surface shake is small. In order to solve this problem, a method has been proposed for stabilizing the surface deflection of a flexible disk medium using aerodynamic stabilization means. As a method using the aerodynamic stabilization means, for example, Patent Documents 1 and 2 are described. As described in Patent Documents 1 and 2, recording of information on a stable disk surface is achieved by using a flexible medium as a recording disk and utilizing the aerodynamic action of the stabilizing member. And reproduction becomes feasible. Patent Document 3 describes the range in which surface runout can be stabilized by using the rigidity of the disk when stabilizing such a flexible disk as a parameter.

  On the other hand, an increase in data transfer rate is demanded as capacity increases. For example, a transfer rate of 250 Mbps in video recording of a broadcast HDTV is one standard. In order to realize this transfer rate over the entire surface of the disk, high-speed driving near 15000 rpm is required to ensure high-speed performance on the inner circumference. Even in this drive, it is important to reduce the vibration of the disk surface from the viewpoint of tracking the focus servo on the disk surface during recording and reproduction.

  Patent Document 1 uses a planar disk-shaped stabilization member, and Patent Document 2 uses a disk-shaped stabilization member that has a concave surface and is curved like a bowl. By adjusting the distance between the recording disks to, for example, 0.05 to 0.30 mm, the rotational driving of the recording disks can be stabilized (even at high speed rotation exceeding 10,000 rpm).

  In these methods, since the recording disk has flexibility and the effect of suppressing the disk vibration by the stabilizing member can be obtained, the conventional rigid body CD, DVD, BD, HD-DVD, etc. The recording disk has the potential to be driven in a high-speed rotation range of 10000 rpm or more, which is difficult to put into practical use. In particular, Patent Document 2 describes a high-speed drive up to about 15000 rpm.

  However, when the recording disk has flexibility and is driven at a high-speed rotation exceeding 15000 rpm, there has been no precedent in the world, and practical problems have been in an unknown area. Based on the configuration of Patent Document 2, the inventors diligently studied the practical application problem in high-speed driving. As a result, when the curvature of the curved stabilizing member, the material and the thickness of the flexible disk change, It turned out to be difficult.

  In Patent Documents 1 and 2, only an optical disk using a polycarbonate having a thickness of about 100 μm is tested, and there is no description about other thicknesses and other materials. Further, in Patent Document 3, since the shape of the stabilizing member is greatly different, it cannot be stabilized even if a disk within a prescribed range is used.

  The present invention solves the above-mentioned problems of the prior art, and in a flexible disk system in which a flexible disk having flexibility is stabilized by an aerodynamic action by a curved stabilizing member and is driven to rotate. To provide a rotating mechanism capable of obtaining stable recording and reproducing characteristics by suppressing surface vibration even during rotation, and a flexible disk system including a recording / reproducing apparatus, and a method for manufacturing a flexible disk. Objective.

In order to achieve the above object, a flexible disk system according to claim 1 of the present invention comprises a flexible disk having flexibility for performing at least one of recording and reproduction of information, and rotating while holding the flexible disk. Turntable, clamper for fixing the flexible disk with the turntable, a spindle motor for rotating the flexible disk together with the turntable and the clamper, and for rotating the flexible disk stably by aerodynamic action A flexible disk system comprising a disk-shaped flexible disk driving means comprising a stabilizing member having a concave surface and curved in a bowl shape, and an information recording / reproducing means , wherein the distance between the stabilizing member and the flexible disk 0.05 0.30 mm, the rotational speed of the floppy disk set in the range of 4000～20000Rpm, the thickness and Young's modulus of the flexible disk, the relationship in the curvature of the curved stabilizer, ".000117 ≦ (Young's modulus (Kg / mm ² )) × (thickness (mm) cubed) / (curvature of stabilizing member (mm)) ≦ 0.00771 ”.

  By defining the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member, it is possible to suppress and stabilize the surface vibration even during high-speed rotation, thereby obtaining good recording and reproduction characteristics. be able to.

  According to a second aspect of the present invention, in the flexible disk system of the first aspect, at least one or a plurality of flexible disks that are loaded, held and rotated on the turntable are housed, and the apparatus main body of the flexible disk system Attached to a disk cartridge that pre-records at least the Young's modulus and thickness information of the flexible disk, showing the relationship between the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member. A solid-state memory.

  By prescribing from the information of the solid memory that records the values derived from the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member, it is possible to suppress and stabilize the surface vibration even during high-speed rotation. Thus, good recording and reproduction characteristics can be obtained.

According to a third aspect of the present invention, in the flexible disk system of the second aspect, the disk cartridge contains a single type of flexible disk, and the Young's modulus and thickness of the flexible disk recorded in advance in the solid-state memory. Information is read and the distance between the flexible disk taken out from the disk cartridge and the stabilizing member is set.

  It can be specified for each flexible disk from the information of the solid memory that records the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member, and can suppress and stabilize the surface runout even during high-speed rotation. Better recording and reproduction characteristics can be obtained.

  According to a fourth aspect of the present invention, in the flexible disk system of the first to third aspects, the diameter of the stabilizing member is larger than the diameter of the flexible disk and covers the entire surface of the flexible disk.

  As a result, the aerodynamic action of the stabilizing member can be exerted also at the end of the flexible disk, and surface runout can be suppressed and stabilized.

  According to a fifth aspect of the present invention, in the flexible disk system of the first to fourth aspects, the ridge line portion at the center of the stabilizing member has a flat portion, and the width of the flat portion is in the range of 5 to 45 mm. It is characterized by.

  By moving along the flat portion, recording and reproduction can be performed without tilting the flexible disk, and stable recording and reproduction can be performed even on the innermost circumference of the flexible disk.

According to a sixth aspect of the present invention, in the flexible disk system of the first to fifth aspects, there is a hole for allowing the clamper to enter the central portion of the stabilizing member, and there is no gap between the inner diameter of the hole and the outer diameter of the clamper. It is characterized by a gap of 5 to 45 mm.

  Stable recording and reproduction can be performed without sliding foreign matter between the inner diameter of the hole and the outer diameter of the shaft, and also on the innermost circumference of the flexible disk.

  According to a seventh aspect of the present invention, in the flexible disk system of the first to sixth aspects, the substrate of the flexible disk is a polycarbonate sheet.

  Thereby, a high-quality flexible disk manufactured at low cost can be used.

  According to the present invention, by regulating the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member, the surface deflection of the flexible disk can be suppressed and stabilized even during high-speed rotation. As a result, it is possible to obtain good recording and reproduction characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS (a) which shows schematic structure of the apparatus main body of the flexible disk system in embodiment of this invention is sectional drawing at the time of stable rotation, (b) is sectional drawing which loads the flexible disk taken out from the disk cartridge, (c) is Transparent perspective view The figure explaining the optical disk in this Embodiment The figure explaining a flat part in the action | operation surface of the stabilization member in this Embodiment The figure which shows the relationship between the numerical value M of each Example in this Embodiment, and maximum surface runout The figure which shows the relationship between (Young's modulus (Kg / mm < ² >)) * (thickness (mm) and the cube) of an optical disk and the maximum gap value stabilized aerodynamically. Diagram showing changes aerodynamically stabilized by gap value

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1A and 1B show a schematic configuration of an apparatus main body of a flexible disk system according to an embodiment of the present invention. FIG. 1A is a sectional view when the flexible disk is stably rotated, and FIG. 1B is a section where a flexible disk taken out from a disk cartridge is loaded. FIG. 4C is a transparent perspective view.

  The apparatus main body 10 according to the present embodiment is an apparatus capable of recording and reproducing information with respect to a flexible flexible disk (hereinafter referred to as an optical disk) 20. As shown in FIG. 1A, the apparatus main body 10 includes a spindle motor (hereinafter referred to as a motor) 22 having a rotary shaft 22a parallel to the Z axis constituting the optical disk driving means, and a rotary shaft 22a of the motor 22. Is connected to a spindle shaft 24 fixed to the + Z side end, a stabilizing member 30 for stabilizing the rotation of the optical disk 20, and recording / reproducing means (not shown), and at least one of information recording and reproduction with respect to the optical disk 20 is performed. A pickup 26 to be performed, and a control unit (not shown) for controlling the pickup 26 and the motor 22 are provided.

  FIG. 1B shows the optical disk driving means and the disk cartridge 11. The disc cartridge 11 contains optical discs 20 (five in the figure), and a solid memory 12 is attached to the outside. When the disc cartridge 11 is loaded in the apparatus main body, the optical disc is taken out from the disc cartridge 11 and chucked by the spindle shaft 24 that is driven to rotate, whereby the optical disc 20 rotates to record and reproduce information.

  Further, as shown in FIG. 1C, the apparatus main body 10 is provided with an electrode plate 13 for accessing the solid-state memory 12 of the disk cartridge 11. When the disk cartridge 11 is loaded into the apparatus main body 10, the electrode plate 13 comes into contact with the solid memory 12, reads information related to the thickness and material of the optical disk from the solid memory 12, and the optical disk 20 and the stabilization member 30 corresponding thereto are read. Set the distance.

  As shown in FIG. 1B, in the optical disk 20, after the disk cartridge 11 is loaded in the apparatus main body 10, a disk transport mechanism (not shown) takes out each optical disk 20 from the disk cartridge 11, and FIG. It is placed on the large-diameter portion 24a (turntable) of (a). The optical disk 20 taken out from the inside of the disk cartridge 11 is rotated by an operation like a so-called disk changer. While the optical disk 20 is rotating, the optical disk 20 is close to the stabilizing member 30. Is away.

  FIG. 2 is a diagram for explaining the optical disk, and the optical disk 20 using the disk substrate shown in Table 1 will be described in detail. As shown in FIG. 2, the optical disk 20 is a disk substrate obtained by cutting a resin sheet into a circular plate shape having an outer diameter of 120 mm and a circular hole formed in the center, and the inner circumference on the −Z side of the sheet 20a. A flexible optical disc 20 in which a recording layer is formed in a region 20b (colored portion shown in FIG. 2) having a diameter of 50 mm to an outer peripheral diameter of 116 mm is used.

The optical disk 20 is a high-speed rotation of a stamper mounted on a spin disk, and an ultraviolet light curable resin is spread to form a transfer layer. A sheet member (disk substrate) is laminated on the transfer layer, and the transfer layer is irradiated with ultraviolet light. Then, this is cured, and then peeled off from the stamper. Further, by sputtering, an Ag reflection layer having a thickness of 120 nm, a (ZrO ₂ —Y ₂ O ₃ ) —SiO ₂ layer having a thickness of 7 nm, and an AgInSbTeGe having a thickness of 10 nm. This is formed by depositing a layer, a ZnS—SiO ₂ layer having a thickness of 25 nm, and a Si ₃ N ₄ layer having a thickness of 10 nm.

  There are two methods for using a thin optical disk: a method in which light used for recording and reproduction is transmitted through a disk substrate, and a method in which light is directly incident on a recording film surface and light is not transmitted through the disk substrate. From this point of view, polycarbonate is excellent in optical properties such as low birefringence and can be applied to either of the methods described above, but polyethylene terephthalate has high birefringence and direct light incidence on the recording film surface. Only the method can be supported. For this reason, in Table 1, polycarbonate and polyethylene terephthalate are exemplified as the disk substrate. However, the range provided is wide in terms of optical characteristics required as an optical disk, and more preferably, a polycarbonate sheet member is used as the disk substrate. By using it, an inexpensive and high quality optical disk can be manufactured.

  Further, on the front and back surfaces of the optical disk 20, a transparent protective film having a thickness of 10 μm is formed by irradiating and curing the UV resin on the spin-coated UV resin to protect the recording layer and the disk substrate. For example, a circular plate 20c having a thickness of 0.1 mm, an outer diameter of 30 mm, and a round hole having an inner diameter of 15 mm formed at the center is attached so that the center thereof coincides with the center of the sheet 20a. Here, for convenience of explanation, as shown in FIG. 2, an XY coordinate system with the center o of the optical disc 20 as the origin is defined.

  As shown in FIGS. 1 and 3, the stabilizing member 30 is a cylindrical member (disc shape) having a low outer diameter of 125 mm with a circular opening having a diameter of 32 mm formed in the center, and a surface on the + Z side. Is fixed to the ceiling surface of the housing 10, and the surface on the −Z side is a concave curved surface (hereinafter also referred to as an action surface) in which the back surface facing the optical disk 20 is curved in only one direction in a bowl shape. The working surface of the stabilizing member 30 is a simple curved surface curved with a curvature radius of 900 mm.

  In addition, by making the outer diameter of the stabilizing member 30 larger than the outer diameter of the optical disc 20 and covering the entire surface of the optical disc 20, the aerodynamic action of the stabilizing member 30 can be exerted on the end portion of the optical disc 20. The surface runout can be reduced.

  Returning to FIG. 1A, the spindle shaft 24 is a stepped cylindrical shape having a cylindrical large diameter portion 24a (turn table) and a small diameter portion 24b (clamper) provided at the upper end of the large diameter portion 24a. It is a member. The optical disk 20 has a rotating shaft 22a of a spindle shaft 24 inserted into a circular hole of a circular plate 20c shown in FIG. 2, is supported from below by an upper surface of a large diameter portion 24a (turn table), and is sandwiched between small diameter portions 24b (clampers). It is fixed and held. Further, the optical disk 20 is mounted on the spindle shaft 24 with the recording layer as the bottom surface and the center thereof coincides with the center of the action surface of the stabilizing member 30. Further, as an example, the optical disc 20 is attached to the spindle shaft 24 such that the distance between the surface opposite to the light incident surface when the optical disc 20 is flat and the flat portion of the working surface of the stabilizing member 30 is 150 μm. It shall be installed.

  The motor 22 drives the rotating shaft 22a to rotate the optical disc 20 through the spindle shaft 24 within a range of about 4000 to 20000 rpm, for example. Further, the rotational speed of the optical disc 20 is controlled by a control unit (not shown).

  The pickup 26 is disposed below the optical disk 20 (on the −Z side), and has a known configuration including a light source, an optical system including an objective lens, a light receiving element, and the like. The pickup 26 condenses the laser beam on the recording surface of the optical disc 20 rotated by the motor 22 and reads (reproduces) information from the optical disc 20 by receiving the reflected light from the recording surface and Write (record) information. Then, as shown by arrows a and a ′ in FIG. 2, a straight line that passes through the center of the optical disc 20 and forms an angle of +10 degrees when the counterclockwise direction is a positive direction with respect to the Y axis in FIG. 2. And driven by a pickup driving device (not shown). The rotation direction of the optical disk at this time is clockwise when viewed from above.

  Next, the operation of the stabilizing member 30 when information is recorded on and reproduced from the optical disc 20 by the apparatus main body 10 configured as described above will be described. When the optical disk 20 rotates, the optical disk 20 has a restoring force that tends to be horizontal due to the centrifugal force generated by the rotation, and a repulsive force due to a pressure change based on a difference in air flow caused by the rotation and the surface shape. Occur. At this time, the stabilizing member 30 applies an aerodynamic force to the optical disk 20 to balance the restoring force and the repulsive force generated in the optical disk 20, so that the so-called surface wobbling of the optical disk 20 (the rotation direction of the optical disk 20). ).

  Based on this principle, it is clear that the flexibility of the optical disc 20, the centrifugal force acting on the optical disc 20, and the force of air are interrelated.

  The thickness of the optical disk 20 affects the mass of the optical disk 20 and affects the centrifugal force. The thickness affects the difficulty of bending of the optical disc 20 together with the Young's modulus of the optical disc 20 itself. Since the curvature of the curved stabilizing member 30 affects the air flow field, the force by the air is influenced. In addition, since the bending curvature of the rotating optical disk 20 is also affected, the restoring force from the bending of the optical disk 20 is also affected.

  As described above, the thickness of the optical disc 20, the Young's modulus of the optical disc 20, and the curvature of the stabilizing member 30 influence each other. In the present invention, these influences are arranged, and the conditions for stable driving with respect to high-speed driving at 15000 rpm have been found.

  The details will be described below.

Example 1
The inventors are a cylindrical member having a low outer diameter of 125 mm with a circular opening having a diameter of 32 mm formed in the center described above, and the working surface is curved with a radius of curvature of 900 mm, and is −X direction and + X direction from the center. The stabilization experiment of the optical disc 20 was performed using the stabilizing member 30 having a flat portion with a long distance (here, 10 mm). This stabilization experiment is caused by surface runout of the optical disc 20 at a point 25, 40, 58 mm apart from the center of the optical disc 20 by changing the rotational speed of the optical disc 20 in steps of 2000 rpm from 4000 rpm to 16000 rpm. The amplitude (μm) in the Z-axis direction is measured with a laser displacement meter.

(Table 2) shows the experimental results, which show the maximum value of the surface runout (the largest value among the three points measured) and the numerical value M at each rotational speed of each disk. The number M is
M = Young's modulus of optical disk (Kg / mm ² ) × (thickness of cube of thickness (mm)) / curvature of stabilizing member (stabilizer) (mm)
It is a value defined by.

  (Table 2) shows that the maximum surface runout value in the table is 10 μm or less or 30 μm or more, and is bipolar. The maximum surface deflection value is 10 μm or less when the optical disk 20 can be stabilized using the stabilizing member 30, and the maximum surface deflection value is 30 μm or less.

Next, looking at the relationship between the maximum surface deflection and the numerical value M, it can be seen that in this experiment, when the numerical value M is 0.000158 or more and 0.00295 or less, the maximum value of the surface deflection is stabilized at 10 μm or less. Therefore, by regulating the numerical value M obtained from the thickness and Young's modulus of the optical disc 20 and the curvature of the curved stabilizing member to 0.000158 or more and 0.00295 or less , the surface deflection of the optical disc 20 can be suppressed and stabilized. It becomes. Thereby, good recording and reproduction characteristics can be obtained.

(Example 2)
Example 2 is the same as Example 1 described above except that the following is used as the stabilizing member 30. The stabilizing member 30 is a low-columnar member (disk shape) having an outer diameter of 125 mm with a circular opening having a diameter of 30 mm formed in the center, and the surface on the + Z side is fixed to the ceiling surface of the main body 10. The surface on the −Z side is a concave curved surface (hereinafter also referred to as an action surface) in which the back surface facing the optical disk 20 is curved in only one direction in a bowl shape (see also FIG. 1). As shown in FIG. 3, the working surface of the stabilizing member 30 has a generatrix L (hereinafter, also referred to as a central generatrix L) that is parallel to the Y axis and passes through the ridge line portion at the center of the actuating surface. Curved with a radius of curvature of 1000 mm. Then, an area defined by two straight lines parallel to the Y-axis that are separated from the central generatrix L in the -X direction and the + X direction by a distance S (here, 17.5 mm) and the outer periphery of the working surface, that is, FIG. The colored region is a flat portion. Further, the pickup 26 moves along a straight line that passes through the center of the action surface of the stabilizing member 30 and forms an angle of +10 degrees with respect to the central generatrix L.

  (Table 3) shows the maximum value of the surface runout and the numerical value M of each disk. In Example 2, it can be seen that when the numerical value M is 0.000142 or more and 0.00771 or less, the value of the maximum surface runout is stabilized at 10 μm or less.

(Example 3)
Example 2 is the same as Example 2 except that the one having a radius of curvature of the working surface of 700 mm is used as the stabilizing member 30.

  (Table 4) shows the maximum value of the surface runout and the numerical value M of each disk. In Example 3, when the numerical value M is 0.000117 or more and 0.00380 or less, it can be seen that the maximum value of the surface runout is stabilized at 10 μm or less.

  Finally, FIG. 4 shows the relationship between the numerical value M and the maximum surface deflection in Examples 1 to 3. As can be seen from FIG. 4, when the numerical value M is 0.000117 or more and 0.00771 or less, the maximum value of the surface runout is stabilized at 10 μm or less.

  Further, when the width of the flat portion of the stabilizing member 30 through which the pickup 26 passes during recording and reproduction of information is less than 5 mm, the optical disc 20 may remain tilted during recording and reproduction, and conversely, the width is reduced. When it exceeds 45 mm, the innermost circumference of the optical disk 20 is not sufficiently stabilized, and surface runout may occur.

  This is an eleven kinds of stabilizing members in which the radius of curvature of the working surface is 1000 mm and the width of the flat portion is replaced with “0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 mm”; Using a thin optical disk with a polycarbonate substrate of 100 μm and 200 μm in thickness, the distance between the optical disk and the stabilizing member (hereinafter referred to as a gap) was set to 100 μm, the rotational speed was set to 10,000 rpm, and the evaluation of surface blur and warpage was performed. .

  When 22 experiments were conducted by combining two types of optical discs and 11 types of stabilizing members, in the case of an optical disc having a thickness of 100 μm, the radius of the optical disc is 50 mm when a combination of stabilizing members having a flat portion of 0 mm and 5 mm is used. On the outer peripheral side (outermost 58 mm), the tangential tilt becomes 0.3 degrees or more, which is a value that hinders recording and reproduction with an optical pickup having a numerical aperture (NA) of 0.85. For this reason, it was judged that there was a problem in terms of tilt when the flat portion was less than 5 mm.

  Similarly, in the case of an optical disc having a thickness of 100 μm, when the flat portion has a combination of a stabilizing member having 45 mm and 50 mm, the optical disc surface deflection exceeds 10 μm at a radius of 25 mm and a radius of 58 mm. For this reason, the width of the flat part of the stabilizing member was determined to be 45 mm at the maximum.

  In addition, as described above, the optical disk 20 has the rotating shaft 22a of the spindle shaft 24 inserted into the circular hole of the circular plate 20c (see FIG. 2) and is supported on the upper surface of the large diameter portion 24a (turn table). It is clamped by the part 24b (clamper). As shown in FIGS. 1A and 1B, a hole 31 through which the small-diameter portion 24b (clamper) enters is in the center of the stabilizing member 30, and the inner diameter of the hole 31 and the small-diameter portion 24b ( There is a gap between the outer diameter of the clamper. When the optical disk 20 is rotated, if this gap is less than 0.5 mm, there is a possibility of sliding due to the inclusion of foreign matter, and if it exceeds 45 mm, stabilization is insufficient at the innermost circumference of the optical disk 20. There is a possibility that surface wobbling will occur.

Further, the distance (gap) between the optical disk capable of stabilizing the aerodynamic action and the stabilizing member differs depending on the thickness and material of the optical disk. For an optical disc of a certain material (polyethylene terephthalate, polycarbonate), the value of “(Young's modulus (Kg / mm ² )) × (thickness (mm) cubed)” can be changed to stabilize the aerodynamic action. FIG. 5 shows the relationship with the maximum gap value.

  Here, the maximum gap value capable of stabilizing the aerodynamic action will be described with reference to FIG. By rotating the optical disc close to the stabilizing member (stabilizer), a thin air layer is formed in the gap between the optical disc and the stabilizing member, and vibration of the optical disc is suppressed. At this time, if the gap value is increased, the vibration of the optical disk increases rapidly with a certain gap value as a boundary.

6, the material of 100μm polycarbonate thickness, the optical disc of Young's modulus 252.1kg / mm ² is rotated at 15000 rpm, at a cylindrical member having an outer diameter of 125mm central circular opening with a diameter 32 mm, the working surface curvature radius It is a figure which shows the example which changed the value of the gap with the stabilizing member which is curving at 900 mm and a flat part is ± 15 mm on both sides of the center generating line L. The vertical axis in FIG. 6 represents the relative runout value in the gap direction at the measurement position 40 mm away from the center of the optical disc. When the gap value is 0.25 mm, the surface deflection of the optical disk is small, but when the gap value is 0.3 mm, a large surface deflection is observed. In the example shown in FIG. 6, the threshold value at which the surface deflection rapidly increases is 0.25 mm.

The value defined in this way is the maximum gap value that can stabilize the aerodynamic action. A cylindrical member with a low outer diameter of 125 mm having a circular opening with a diameter of 30 mm at the center as in the second embodiment, and a flat working surface with a radius of curvature of 1000 mm and a flatness of ± 17.5 mm in the X direction. Measurement was performed at three measurement positions of 25, 40, and 58 mm from the center of the optical disk using a stabilizing member having a portion. The gap amount at which the maximum value of the surface blur is 20 μm or more is defined as “maximum gap that can be stabilized” in FIG. FIG. 5 shows the maximum stable gap value with respect to the value of “(Young's modulus (Kg / mm ² )) × (thickness to the third power of mm)” of the optical disc. / Mm ² )) × (thickness (mm) to the third power) ”, when“ optimized ”(Young's modulus (Kg / mm ² )) × (thickness (mm) to the third power) It can be seen that stabilization is possible with the largest gap value.

Accordingly, when “(Young's modulus (Kg / mm ² )) × (thickness (mm) to the third power)” of the optical disk is known, such as when the optical disk is started to rotate, the flexible disk system has the maximum gap value. It is possible to start by setting a gap on the main body of the machine. Since the optical disk and the stabilizing member (stabilizer) are likely to slide during startup, it is desirable to start up with a larger gap value. However, if it is too large, the surface shake of the optical disk is conversely large and the sliding becomes severe.

Therefore, a small solid-state memory is attached to the disk cartridge for storing the optical disk, and “(Young's modulus (Kg / mm ² )) × (thickness (mm) of the optical disk” is one of the data recorded in advance here. Record the value of the cube. When the disk cartridge is inserted, the main body of the apparatus accesses the solid memory attached to the disk cartridge, and the optical disk “(Young's modulus (Kg / mm ² )) × (thickness (mm) cubed)” Read information. A gap is set to the maximum gap value corresponding to this, and the optical disk is started to rotate.

  The essence of determining the maximum gap value that can stabilize this aerodynamic action is the three elements of the thickness of the optical disc, the hardness of the optical disc, and the shape of the stabilizing member (stabilizer).

Also, the maximum gap value varies depending on the curvature of the stabilizing member (stabilizer). Since the stabilizing member (stabilizer) differs depending on the main body of the apparatus, the information written in the solid memory of the disk cartridge is not directly the maximum gap value, but “(Young's modulus (Kg / mm ² )) × (thickness (mm) of the optical disk. ) To the third power) ”. By determining the gap value from the value of “(Young's modulus (Kg / mm ² )) × (thickness (mm) to the third power)” and the curvature of the stabilizing member (stabilizer), the main body of the device The optical disk is rotated and started by setting the gap to the maximum gap value corresponding to the stabilizing member (stabilizer).

  Specifically, the optical disk 20 taken out by the disk transport mechanism (not shown) from the disk cartridge 11 loaded in the apparatus main body 10 shown in FIGS. After being placed on the large diameter portion 24a (turn table) and sandwiched by the small diameter portion 24b (clamper), the optical disc 20 rotates. When the rotation starts and reaches a certain number of rotations, a base (not shown) that moves up and down with the motor 22 rises and moves from the information previously read from the solid-state memory 12 to a position that becomes the gap of the maximum gap value. The optical disk 20 is moved while detecting the position by a sensor (not shown) or the like.

  In this way, regardless of changes in the hardness of the optical disk due to future advancement of the optical disk material and the design value of the stabilizing member (stabilizer), the main body of the flexible disk system should have a maximum gap that should be set at startup. The value can be set easily, and sliding between the optical disk and the stabilizing member that occurs at the time of startup can be avoided.

In this example, “(Young's modulus (Kg / mm ² )) × (thickness (mm) to the third power)” was recorded in the solid memory attached to the disk cartridge. The same function can be achieved even if recorded as individual numerical values. A calculation of “(Young's modulus (Kg / mm ² )) × (thickness (mm) to the third power)” may be performed on the Young's modulus read on the apparatus main body side and the thickness of the optical disc.

  As described above, in the present embodiment, even when the optical disk is rotated at a high speed exceeding 15000 rpm in the flexible disk system in which the aerodynamic action is stabilized and rotated by the curved stabilizing member, the flexible optical disk is rotated. Therefore, it is possible to provide a flexible disk system including a disk driving unit and a recording / reproducing unit that can cause recording and reproduction of an optical disk without problems with less surface vibration.

  The present invention is applied to a flexible disk system, a flexible disk, and a disk cartridge having a recording / reproducing apparatus for performing recording and / or reproducing processing on a flexible disk having flexibility, and the flexible disk is a phase change memory. It applies to all disc-shaped recording disks such as magneto-optical memory and hologram memory.

DESCRIPTION OF SYMBOLS 10 Apparatus main body 11 Disk cartridge 12 Solid memory 13 Electrode plate 20 Optical disk 20a Sheet 20b Area | region 20c Circular plate 22 Motor 22a Rotating shaft 24 Spindle shaft 24a Large diameter part 24b Small diameter part 26 Pickup 30 Stabilization member 31 Hole

JP 2006-107699 A JP 2007-149411 A JP 2004-355786 A

Claims (7)

A flexible disk having flexibility for performing at least one of recording and reproduction of information;
A turntable for holding and rotating the flexible disk, a clamper for sandwiching and fixing the flexible disk together with the turntable, a spindle motor for rotating the flexible disk together with the turntable and the clamper, and the flexible disk A flexible disk drive means comprising a disk-shaped stabilizing member having a concave surface and curved like a bowl, and a recording / reproducing means for recording and reproducing the information. A disk system,
The distance between the stabilizing member and the flexible disk is 0.05 to 0.30 mm, and the rotational speed of the flexible disk is within a range of 4000 to 20000 rpm,
The relationship between the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member is
0.000117 ≦ (Young's modulus (Kg / mm ² )) × (thickness (mm) cubed) / (curvature of stabilizing member (mm)) ≦ 0.00771
A flexible disk system characterized by being in the range. A disk cartridge that houses at least one or a plurality of flexible disks that are loaded, held and rotated on the turntable, and is detachable from the apparatus main body of the flexible disk system;
A solid-state memory attached to the disk cartridge, in which at least information on Young's modulus and thickness of the flexible disk is recorded in advance, which indicates a relationship between the thickness and Young's modulus of the flexible disk and the curvature of the curved stabilizing member; The flexible disk system according to claim 1, further comprising: The disk cartridge contains a single type of flexible disk,
Claim 2, wherein the solid-state memory to the read prerecorded to have Young's modulus and thickness information of the flexible disk, setting the distance between the stabilizing member and the flexible disk taken out from the disc cartridge The flexible disk system described.   The flexible disk system according to claim 1, wherein a diameter of the stabilizing member is larger than a diameter of the flexible disk and covers the entire surface of the flexible disk.   5. The flexible disk system according to claim 1, wherein a flat portion is provided at a ridge line portion at a center portion of the stabilizing member, and a width of the flat portion is in a range of 5 to 45 mm. . 6. A hole for allowing the clamper to enter in a central portion of the stabilizing member, and a gap of 0.5 to 45 mm is provided between an inner diameter of the hole and an outer diameter of the clamper. The flexible disk system according to any one of the above.   The flexible disk system according to claim 1, wherein the substrate of the flexible disk is a polycarbonate sheet.

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