JP2005339764A - Disk drive device and information recording / reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress disc tilt due to the weight of a disc with a simple configuration.
A turntable 5 is disposed below a disk 1, and a pressing member 9 is disposed above the disk 1. The turntable 5 includes a disk mounting portion 5 a that contacts the disk 1. The pressing member 9 includes a pressing portion 9 a that presses the lower surface of the disk 1 and rotates together with the disk 1. The alignment ring 7 presses the inner end of the disk 1 from below. The disc mounting portion 5a is disposed on the inner peripheral side with respect to the pressing portion 9a.
[Selection] Figure 2

Description

  The present invention relates to a disk drive device for driving a disk-shaped information recording medium such as an optical disk and an information recording / reproducing apparatus including the same, and more particularly to a technique for holding a disk-shaped information recording medium.

  In recent years, portable disc-shaped signal recording media such as optical discs and magnetic discs have been widely used, and the recording density thereof is, for example, a 640 Mbyte compact disc (CD), 4.7 to 9.4 GByte for an optical disc having a diameter of 12 cm. DVD and 25-50 Gbyte Blu-ray discs are becoming increasingly dense.

  The optical disk device irradiates a disk recording surface with laser light emitted from an optical pickup, detects the reflected light, and reads information. The optical disk apparatus records data by changing the state of the recording film on the disk recording surface. At this time, if the laser beam and the disk recording surface are relatively inclined, an aberration called coma aberration occurs, which hinders signal reproduction and recording.

  Various tilt correction mechanisms have been proposed to correct the tilt (hereinafter referred to as tilt) between the disk recording surface and the optical pickup.

  For example, there has been proposed a system in which a tilt sensor for detecting the tilt of a disk is mounted on the optical pickup, and the optical pickup is tilted or the objective lens is tilted so as to correct the tilt detected by the tilt sensor.

  On the other hand, as disclosed in Patent Document 1, a disc holding method for correcting the tilt of the disc itself has been proposed. In this configuration, the warp of the disk is corrected by making the clamper that holds the disk on the turntable as large as the disk.

  FIG. 10 shows a disk holding method in a conventional general optical disk apparatus. FIG. 11 shows a disk holding method in the disk device described in Patent Document 1.

  As shown in FIG. 10, in a general optical disc apparatus, an optical disc 101 is mounted on a turntable 102 and is held by the clamper 103 and held on the turntable 102. The clamper 103 and the turntable 102 sandwich the disc 101 at substantially the same position in the radial direction, and the widths of the sandwiching portions of both are substantially the same. In this type of optical disk apparatus, since the optical disk 101 on the outer peripheral side than the turntable 102 is deformed so as to hang down due to its own weight, by adjusting the tilt angle of the objective lens on the optical pickup side (not shown), etc. The optical characteristics are not impaired.

On the other hand, in the disk device described in Patent Document 1 shown in FIG. 11, the clamper 104 that moves the disk 101 along the turntable 102 is configured to have a size that covers almost the entire surface of the disk. The optical disk 101 is pressed from above to function as a stabilizer that reduces warpage.
JP-A-8-167272

  However, the conventional method of tilting the objective lens according to the detection result of the tilt sensor requires a new drive mechanism for tilting the tilt sensor and the optical pickup, which not only complicates the configuration but also makes it difficult to reduce the cost. Has the problem of becoming. In addition, there is a problem in that power consumption increases because extra power is required according to the angle adjustment amount of the objective lens. In addition, a design with a sufficient space is required in accordance with an increase in the amount of angle adjustment, which hinders downsizing of the apparatus.

  On the other hand, in the configuration of the conventional example described in Patent Document 1, since the shape of the stabilizer 104 used as a clamper is large, it is difficult to reduce the size of the apparatus. In addition, since the mass that rotates integrally with the disk 101 increases, a motor with a large torque is required, which causes an increase in cost.

  The disc 101 is supported by the turntable 102. A downward moment is generated on the disc 101 by the weight of the disc 101 outside the turntable 102, and this is one of the factors of disc tilt. However, even if the clamper 104 is provided, this disc tilt cannot be eliminated.

  Further, in the optical disc apparatus, an area for holding the disc, that is, a clamp area is defined as a diameter of 22 mm to 32 mm (radius of 11 mm to 16 mm) in a CD or DVD, for example. However, in an actual optical disk device, the objective lens of the optical pickup can be reliably accessed to the innermost peripheral area of the disk, so that the turntable of the disk motor is not the entire clamp area but only the inner peripheral side. In many cases, the objective lens driving unit of the optical pickup is configured to be movable to the inner peripheral side. On the other hand, in a disk tilt measuring machine that evaluates the tilt of a disk, the disk is held in a clamp area defined by a standard. Therefore, there is a problem that the disc tilt measured by the disc tilt measuring device and the disc tilt generated in the optical disc apparatus may be different.

  Accordingly, the present invention has been made in view of such a point, and an object of the present invention is to suppress disc tilt due to the weight of the disc with a simple configuration.

  In order to solve the above problems, the present invention presupposes a disk drive device that drives a disk, and contacts the disk and rotates together with the disk, and the disk mounting part of the disk is opposite to the disk mounting part. A pressing portion that presses the side surface and rotates together with the disc, and the pressing portion and the disc mounting portion are positions that generate a moment in a direction to cancel the moment generated in the disc by the weight of the disc. Set in a relationship.

  In this configuration, the pressing portion and the disc mounting portion generate a moment in a direction that cancels out the moment caused by the disc's own weight, so that the disc tilt can be reduced.

  Further, the present invention is a disk drive device for driving a disk, wherein the disk is in contact with the lower surface of the disk and rotates together with the disk, and is disposed above the disk mounting part. It is good also as a structure provided with the press part which presses an upper surface and rotates with the said disk, and the said press part is arrange | positioned rather than the said disk mounting part.

  In this configuration, the disc tilt can be suppressed by the pressing portion.

  Further, the present invention is a disk drive device for driving a disk, wherein the disk is in contact with the upper surface of the disk and rotates together with the disk, and is disposed below the disk mounting part. It is good also as a structure provided with the press part which presses a lower surface and rotates with the said disk, and the said disk mounting part is arrange | positioned in the inner peripheral side rather than the said press part.

  In this configuration, the disc tilt can be suppressed by the disc mounting portion.

  The disc is provided with a center hole, and a contact portion that contacts the peripheral edge of the center hole in the disc and rotates together with the disc is provided. The disk may be brought into contact with the disk from the same side as the disk mounting portion.

  In this configuration, even if the moment due to the weight of the disc and the moment due to the force received from the contact portion are in the same direction, these moments are reduced by the pressing portion and the disc mounting portion, and the disc tilt Can be suppressed.

  In this case, the contact portion has a tapered surface that can contact the peripheral edge of the center hole of the disc and is formed concentrically with the rotational axis of the disc, and the tapered surface is the center of the disc. It is preferable that the disk is centered by contacting the peripheral edge of the hole.

  The pressing portion may be formed in a plurality of protrusions arranged at intervals in the circumferential direction. In this case, the pressing portion is formed in a shape that makes point contact in a radial cross section. Is preferred.

  The present invention may also be an information recording / reproducing apparatus that includes the disk drive device and an optical head, and records and reproduces information by irradiating the disk with the optical head while driving the disk with the disk drive device. Good.

  As described above, according to the disk drive device of the present invention, the tilt generated by the weight of the disk can be reduced with a simple configuration.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 and 2 show an embodiment of a disk drive device 30 according to the present invention. FIG. 1 is an exploded perspective view of the main part of the optical disk apparatus including the disk drive device 30, and FIG. 2 is a cross-sectional view showing a state in which the disk 1 is held on the turntable 5.

  The disc 1 is formed in a disc shape provided with a central hole 1a, and is provided with an information recording unit for recording information or an information recording unit on which information is recorded. The optical head 2 reads information recorded in the information recording unit of the disk 1 or records information on the disk 1. The optical head 2 is held by a chassis 3 so as to be movable in the radial direction along the information recording surface of the disk 1. A disk motor 4 for rotating the disk 1 is fixed to the chassis 3.

  The disk motor 4 includes a turntable 5 that rotates integrally with the rotating body 4 a of the disk motor 4, a magnet 6 disposed above the turntable 5, and a central portion of the turntable 5. The alignment ring 7 and the central shaft 4b are integrally formed.

  The alignment ring 7 is for aligning the center of the disk 1 with the center of rotation of the disk motor 4. That is, the alignment ring 7 plays a role of the centering function of the disk 1.

  The turntable 5 is disposed below the disk 1. The turntable 5 includes a table body 5b fixed to the rotating body 4a of the disk motor 4 and a disk mounting portion 5a provided on the outer periphery of the table body 5b. The disk mounting portion 5 a protrudes upward from the table main body portion 5 b, and the upper end surface of the disk mounting portion 5 a is in contact with the lower surface of the disk 1. In other words, the disk 1 receives a pressing force from the disk mounting portion 5a on its lower surface. The disk mounting portion 5a is configured by a member having a large friction coefficient such as resin or rubber so as to prevent the disk 1 from slipping when the motor rotates.

  The alignment ring 7 includes an outer end portion having a tapered surface 7a having a diameter that decreases toward the upper side. The tapered surface 7a is concentric with the central shaft 4b of the disk motor 4 and is disposed so as to be able to contact the central hole 1a of the disk 1. When the chassis 3 moves up and the disk 1 is mounted on the turntable 5, the taper surface 7 a comes into contact with the peripheral edge of the center hole 1 a of the disk 1, and the center of the disk 1 and the disk motor 4. Guide to a position that matches the center of rotation. The alignment ring 7 is included in the concept of the contact portion in the present invention, and is configured to be able to contact the inner end portion (the peripheral portion of the center hole 1a) on the lower surface of the disk 1.

  The alignment ring 7 is supported so as to be movable in the direction of the rotation axis of the disk motor 4 by a coil spring 20 mounted on the center shaft 4 b of the disk motor 4. The coil spring 20 urges the alignment ring 7 upward. That is, the disk 1 receives an upward pressing force through the alignment ring 7 at the inner end. The aligning mechanism using the aligning ring 7 enables reliable centering of the disk 1 while using relatively low cost parts such as a sheet metal pressed product and a resin molded product.

  A clamper 8 is disposed above the turntable 5. The clamper 8 includes a pressing member 9 that presses the disk 1, a magnetic body 10, and a holder 11 that holds the magnetic body 10 and the pressing member 9. The pressing member 9 and the holder 11 are held by the upper lid member 12. Specifically, a through hole is provided in the upper lid member 12, and the peripheral portion of the through hole in the upper lid member 12 is sandwiched between the pressing member 9 and the holder 11 with a gap, The pressing member 9 and the holder 11 are coupled to the upper lid member 12.

  The magnetic body 10 is held in a state sandwiched between the pressing member 9 and the holder 11. The magnetic body 10 is disposed above the magnet 6 disposed in the disk motor 1 and is attracted by the magnet 6. By this magnetic attraction force, the pressing member 9 presses the disk 1 downward. In this state, the disk 1 is sandwiched between the pressing member 9 and the turntable 5. The pressing member 9 and the turntable 5 are configured to have substantially the same diameter.

  On the lower surface of the pressing member 9, a pressing portion 9 a having a shape protruding downward is provided. The pressing portion 9 a is provided at an intermediate portion in the radial direction of the pressing member 9, and the lower end portion of the pressing portion 9 a is in contact with the disk 1. In other words, the disc 1 receives a downward pressing force from the pressing portion 9a on the upper surface on the inner peripheral side (near the center) of the disc mounting portion 5a.

  Next, an operation in which the disk 1 is mounted on the turntable 5 and held by the clamper 8 will be described.

  The disk 1 is mounted on the tray 13 and is carried inside the disk device by a disk loading mechanism (not shown). Thereafter, the chassis 3 evacuated downward in order to avoid interference with the tray 13 is raised by a lifting mechanism such as a lifting motor or a cam (not shown). At this time, the disk motor 4 fixed to the chassis 3 is also raised. The alignment ring 7 contacts the edge of the center hole 1a of the disk 1 and guides the disk 1 to a position where the center of the disk 1 and the rotation axis of the disk motor 4 coincide with each other. Lift from tray 13.

  Immediately before the raising of the chassis 3 is finished, the clamper 8 held by the upper lid member 12 and the disk 1 come into contact with each other, and the clamper 8 is lifted to a position where it does not come into contact with the upper lid member 12. At the same time, the magnet 6 disposed at the center of the disk motor 4 and the magnetic body 10 of the clamper 8 approach each other, and a magnetic attractive force acts. This magnetic attraction force is set to be sufficiently larger than the urging force by the coil spring 20 of the alignment ring 7. For this reason, the disk 1 is pushed down the aligning ring 7 at the same time as being centered (aligned), and the disk 1 is pushed down until it comes into contact with the turntable 5 and is in contact with the turntable 5. Fixed.

  When releasing the holding of the disk 1, the chassis 3 is moved downward. As a result, the magnet 6 is retracted downward and the magnetic attractive force with the clamper 8 is released. At this time, the disk 1 is mounted on the tray 13, and the clamper 8 is held by the upper lid member 12 and is in a state of waiting above.

  In addition, the structure which generate | occur | produces the pressing force for pressing and hold | maintaining the disk 1 against the turntable 5 is not restricted to this structure. For example, a magnetic material may be disposed on the disk motor 4 side and a magnet may be disposed on the clamper 8 side to generate an attractive force. Moreover, the structure which acquires not only the magnetic attraction force by a magnet and a magnetic body but a spring member may be sufficient.

  Next, the load and moment applied to the disc 1 in a state where the disc 1 is held on the turntable 5 by the clamper 8 will be compared with the conventional configuration with reference to FIGS. 3 (a) to 3 (c). . FIG. 3A to FIG. 3C are schematic representations of cross-sectional views when cut along the radius of the disk 1.

  FIG. 3A is a radial cross-sectional view of the disk drive device 30 in the present embodiment. In this disk drive device 30, the disk 1 is supported by the disk mounting portion 5 a of the turntable 5. A support point by the disk mounting portion 5a is shown as Pt. In addition to the supporting force at the supporting point Pt, the pressing force (hereinafter referred to as clamping force) Fc by the clamper 8, the urging force Fr by the alignment ring 7, and the own weight Fg of the disk 1 act on the disk 1. doing. Here, for simplification, only a part having a unit width in the circumferential direction is considered. The self-weight Fg of the disk 1 is actually a distributed load, but acts as a concentrated load at the radial center of gravity position in the portion. In order to simplify the description, it is assumed that each load shown in FIGS. 3A to 3C acts on the part. Strictly speaking, since the portions are continuously distributed in the circumferential direction, it differs from a load or a moment generated only in an actual cross section.

  In FIG. 3A, the moment around the support point Pt is obtained.

Since the weight of the disk 1 acts as a concentrated load Fg at a position away from the support point Pt of the disk mounting portion 5a by a distance Lg, the moment Mg due to the weight of the disk 1 is positive (clockwise in FIG. 3 (a)). ), And its value is
Mg = Lg × Fg (1)
Can be expressed as In other words, in a state where the disk 1 is merely placed on the turntable 5, the disk 1 tends to tilt in a direction in which the outer side hangs down below the disk mounting portion 5a due to its own weight.

On the other hand, the urging force Fr of the aligning ring 7 acts on the position where the distance from the support point Pt is Lr. Therefore, the moment Mr due to the urging force Fr acts in the positive direction, and its value is
Mr = Lr × Fr (2)
Can be expressed as

Further, since the clamping force Fc acts on the position of the distance Lc from the support point Pt, the moment Mc caused by the clamping force Fc acts in the negative direction (counterclockwise direction in FIG. 3A), and its value. Is
Mc = Lc × Fc (3)
Can be expressed as However, as described above, the clamp Fc is set to be larger than the urging force Fr of the alignment ring 7 in order to securely fix the disc 1 to the turntable 5.

From the above, if the moment around the support point Pt is Md1, the moment Md1 is
Md1 = Mg + Mr-Mc (4)
Therefore, the moment Md1 acts on the disk 1 as a residual component of Mg, Mr, and Mc. This moment Md1 acts to rotate the disk 1 around the support point Pt, or acts as deformation energy of the disk 1. That is, the smaller the moment Md1, the smaller the influence on the posture and deformation given to the disc 1, and the occurrence of disc tilt can be suppressed. Actually, the disk 1 is continuous in the circumferential direction, and the moment Md1 is decomposed into components in the circumferential direction, so that the disk is stable in a balanced state after a certain rotation or deformation.

  As described above, the disk 1 receives the moment in the positive direction (clockwise) around the support point Pt, that is, the moment in the direction in which the outer periphery of the disk 1 is lowered, by the moment Mg and the moment Mr. Further, the moment Mc due to the clamping force Fc acts on the disk 1 in a direction to cancel it. In other words, the support generated as a result of the disc 1 by positively applying a moment opposite to the moment acting on the disc 1 by the own weight Fg of the disc 1 and the biasing force Fr by the alignment ring 7 by the pressing portion 9a. The moment around the point Pt is reduced. Therefore, in the disk drive device 30 according to the present embodiment, the moment Md1 generated in the disk 1 is reduced, so that the attitude of the disk 1 can be made more stable.

  The moment Mc depends on the magnitude of the clamping force Fc and the distance Lc from the fulcrum Pt. Therefore, an arbitrary moment Mc can be obtained by adjusting Fc and Lc.

  Further, the support area for supporting the disk 1 by the turntable 5 is located on the inner peripheral side of the clamp area defined by the CD or DVD. This support area has a radius of about 12 to 14 mm, for example.

  Next, a disk holding method in the conventional disk drive shown in FIG. In this disk drive device, the operation position of the clamping force Fc is different from that of the present embodiment shown in FIG. That is, the action point of the clamping force Fc is substantially the same radial position as the disk support point Pt of the turntable 5. Others are the same as those in FIG.

Since the moment Mc around the support point Pt by the clamp Fc is almost 0, the moment Md2 around the support point Pt acting on the disk 1 is
Md2 = Mg + Mr (5)
It can be expressed as. In other words, the sum of the moment Mg due to its own weight and the moment Mr due to the alignment ring 7 is generated in the disk 1 as a clockwise (positive direction) moment. That is, in the conventional disk drive device, unlike the disk drive device 30 according to the present embodiment shown in FIG. 3A, the moment Mc that cancels Mg and Mr cannot be generated, so the outer peripheral side of the disk 1 is lowered. There is a possibility that the tilt of the disc is tilted in the direction and tilting occurs, making it difficult to record and reproduce stable signals.

  FIG. 3C is shown for reference. FIG. 3C is a radial sectional view of a disk holding method in a disk tilt measuring machine for evaluating the tilt of the disk 1. The disc tilt measuring machine is configured to clamp a clamping area adopted as a standard of the disc 1 with a predetermined clamping force. Therefore, in the disc tilt measuring machine, the disc 1 is clamped in the entire clamping area of the disc 1. For example, in a CD or DVD, an area having a radius of 11 mm to 16 mm is a clamp area, and in a disk tilt measuring machine, a disk mounting surface of the turntable 15 and a disk pressing surface of the clamper 18 are configured in an area of radius 11 mm to 16 mm. Yes.

  In addition, since the disk tilt measuring device does not require downsizing of the apparatus, it is not necessary to adopt a configuration in which a magnetic attraction force is generated in a small space using a magnet or a magnetic material, and a clamper as shown in FIG. The clamping force is obtained by increasing the size of 18. As a result, the disk tilt measuring machine clamps the disk 1 with a clamping force that is several times the clamping force of the disk drive device.

  Further, unlike a disk drive device that is strongly required to reduce the cost, a disk tilt measuring machine is required to have a disk holding method with high accuracy even if it is somewhat expensive and with a small load on the disk. For example, the disk 1 is centered by the positioning pins without using an alignment ring as in the disk drive device. This positioning pin is machined with high accuracy, and the positioning of the disk 1 can be performed by inserting the positioning pin into the center hole 1a of the disk 1. Therefore, it is not necessary to press the peripheral portion of the center hole 1a of the disk 1 by the tapered surface 7a unlike the disk drive device 30. For this reason, the disc tilt measuring machine does not generate an urging force that pushes the periphery of the center hole 1a of the disc 1 upward.

Further, in the disk tilt measuring machine, as shown in FIG. 3C, the clamping force by the turntable 15 and the clamper 18 can be approximated as a uniform load over the entire clamping region, and in opposite directions. It can be approximated that the balance is maintained by acting on the disk 1 and the disk 1 is a fixed end in the clamping region. For this reason, it can be considered that only the moment Mg due to its own weight Fg is generated around the clamp region in the disk 1. Therefore, in the disc tilt measuring machine, the moment Md3 around the fixed end generated in the disc 1 is
Md3 = Mg (6)
It becomes. Since the disk 1 has a fixed end in the clamp area, even if the disk 1 is deformed by the moment Mg due to its own weight, the tilt that lifts the inner end of the disk 1 does not occur. In other words, unlike a conventional disk drive device, the disk tilt measuring machine has few factors that cause tilt by holding the disk 1.

  On the other hand, in the disk drive device 30 of the present embodiment shown in FIG. 3A, a clamping force by the pressing member 9 is applied between the support point Pt and the force point of the alignment ring 7. The clamping force by the pressing member 9 is used to cancel the moment due to the disc weight and the biasing force of the alignment ring 7. As a result, it is possible to suppress the tilt that the inner end portion of the disk 1 is lifted, and it is possible to approach the holding state of the disk tilt measuring machine without generating a large clamping force.

  Here, the relationship between the clamping force Fc and the disc tilt will be described.

  FIG. 4 is a diagram in which the disc tilt with the clamping force Fc on the horizontal axis and the disc 1 held on the vertical axis is taken. 4A shows the disk tilt by the holding method in the disk drive device 30 of the present embodiment, and B shows the disk tilt by the holding method in the conventional general disk drive device. In this disc tilt, the direction in which the outer peripheral side of the disc 1 is lifted up is defined as +.

  As can be seen from the figure, when the clamping force Fc is increased in both cases, the disc tilt shifts in the + direction. That is, by increasing the clamping force Fc, the disc 1 can be shifted in a direction to reduce the disc tilt in which the outer peripheral portion of the disc 1 is lowered. However, in the conventional holding method represented by B, the disc support point and the acting point of the clamping force have substantially the same radius, so that the disc tilt hardly changes even when the clamping force is increased. For example, even if the clamping force is increased, the disc tilt can only be reduced from about -0.10 degrees to about -0.08 degrees. In contrast, in the present embodiment represented by A, not only can the disc tilt be reduced from about -0.06 degrees to about -0.02 degrees, but also with an increase in clamping force as compared with the conventional one (B). The effect of reducing the disc tilt can be further increased. Therefore, it can be seen that the disk drive device 30 according to the present embodiment is configured to easily adjust the disk tilt by adjusting the clamping force.

  FIG. 5 shows the relationship between the moment ratio and the disc tilt. In FIG. 5, the horizontal axis represents the moment ratio Mc / (Mg + Mr), and the vertical axis represents the disc tilt by the holding method in the present embodiment. In this figure, the moment ratio Mc / (Mg + Mr) is a ratio of absolute values of moments, and the disc tilt is an absolute value.

  As can be seen from the figure, the disc tilt gradually decreases as the ratio Mc / (Mg + Mr) of the counterclockwise moment to the clockwise moment increases. When the disc tilt allowable range is set to 0.06 degrees, the moment ratio may be set to 0.7 or more. When the disc tilt allowable range is set to 0.05 degrees, It can be understood that the moment ratio may be set to 0.8 or more, and when the allowable range of disc tilt is set to 0.04 degrees, the moment ratio may be set to 0.95 or more. That is, by appropriately setting the moment Mc due to the clamping force Fc, it is possible to suppress the disc tilt generated by the disc holding.

  Factors that cause the total tilt, which is the tilt of the optical axis of the optical head 2 with respect to the recording surface of the disk 1, include, for example, an adjustment residual (optical system) of the optical axis inside the optical head, and a guide axis when the optical head moves. There are many factors such as the tilt of the optical disk (drive system) and the warp of the optical disk itself. In designing the optical disk apparatus, the allowable value of the total tilt is assigned to the optical system, the drive system, and the optical disk itself, and the allowable value in the drive system is set to, for example, 0.10 to 0.20 degrees. ing. For this reason, it is desirable to set the allowable value for the optical disk sufficiently smaller than this, and it is very effective if the allowable range of the disk tilt can be set to 0.04 degrees to 0.06 degrees, for example.

  As described above, in the disk drive device 30 according to the present embodiment, the disk pressing position on the turntable 5 by the pressing portion 9a of the clamper 8 exists on the inner peripheral side with respect to the disk support position by the disk mounting portion 5a. Therefore, the moment generated by the disc's own weight on the outer peripheral side from the disc support position and the moment generated by the biasing force of the alignment ring 7 can be offset. Therefore, disc tilt can be suppressed with a simple configuration, and signal recording and reproduction can be ensured.

  Further, since the disk tilt can be suppressed, the amount of angle adjustment of the objective lens 2a (see FIG. 2) performed on the optical head 2 side can be reduced. For this reason, the electric current value used for the attitude | position holding | maintenance of the objective lens 2a in the optical head 2 can be reduced, and power consumption can be reduced. In addition, since the angle range (dynamic range) for tracking the objective lens 2a can be reduced, the moving speed of the objective lens 2a can be increased and the optical characteristics can be improved. Further, since the angle adjustment amount of the objective lens 2a can be reduced, it is advantageous in terms of space and contributes to the thinning of the disk device. In addition, since the angle adjustment amount of the objective lens 2a can be reduced, it is possible to make coma aberration less likely to occur in the objective lens 2a, and the degree of freedom in designing the objective lens 2a can be improved. Even in a disk device that does not perform tilt correction on the optical head side, the required accuracy for each component can be reduced, which contributes to cost reduction.

  Here, a specific configuration of the pressing portion 9a of the pressing member 9 will be described. As shown in FIG. 6, the pressing part 9a may be divided into a plurality of parts so as to be arranged at intervals in the circumferential direction. FIG. 6 is a perspective view of the pressing member 9 viewed from the disk direction (downward). In this embodiment, the press part 9a is arrange | positioned at six places of the circumferential direction, and each press part 9a is formed in protrusion shape. In such a configuration in which a plurality of small protruding pressing portions 9a are arranged in the circumferential direction, the flatness of the pressing surface that presses the disk 1 can be easily obtained, and the point for pressing the disk 1 is ensured. Thus, a more stable posture of the disk 1 can be obtained. Further, if the configuration is arranged at six equal intervals in the circumferential direction, the influence of the undulation on the surface of the disk 1 can be alleviated, and a stable disk posture can be obtained. In the conventional arrangement in which the disk mounting portion of the turntable and the pressing portion of the pressing member are opposed to each other, it is necessary to increase the pressing area to some extent in order to stably hold the disc. On the other hand, in the first embodiment, the pressing portion 9a of the pressing member 9 is disposed between the disk mounting portion 5a of the turntable 5 and the contact portion by the alignment ring 7, so that the pressing portion 9a is pressed. Even if the surface is reduced, the disk 1 can be stably held. In addition, the press part 9a is not restricted to the structure divided | segmented into the circumferential direction, For example, you may comprise in the annular | circular shape connected in the circumferential direction.

  As shown in FIG. 7, the pressing portion 9 a can have a shape that makes point contact with the disk 1 in the radial cross section. For example, the pressing portion 9a may have a triangular cross section in the radial direction or an arc shape. By adopting such a shape, the point at which the disc 1 is pressed is further ensured, so that the posture of the disc can be further stabilized.

  In the first embodiment, the configuration in which the inner end portion of the disk 1 is pressed by the alignment ring 7 has been described. However, the present invention is not limited to this. For example, the present invention can be applied to a disk drive device in which the alignment ring 7 is not provided.

(Embodiment 2)
FIG. 8 partially shows a disk drive device 30 according to the second embodiment of the present invention. As shown in the figure, the second embodiment has a structure in which the disk drive device 30 of the first embodiment is disposed upside down.

  More specifically, the turntable 5 is fixed to the lower end portion of the rotating body 4a of the disk motor 4. A disk 1 is disposed below the turntable 5.

  The outer end portion of the alignment ring 7 is upside down with respect to the first embodiment, and has a tapered surface 7a whose outer diameter becomes smaller toward the lower side. For this reason, the taper portion 7 a comes into contact with the upper end portion of the inner end portion of the disk 1.

  The pressing member 9 is disposed below the turntable 5 so that the disk 1 is sandwiched between the pressing member 9 and the turntable 5.

  The pressing member 9 is configured to have a larger outer diameter than the turntable 5. The disk mounting portion 5 a of the turntable 5 is disposed on the inner peripheral side with respect to the pressing portion 9 a of the pressing member 9. As a result, the disk mounting portion 5a of the turntable 5 is arranged to generate a moment in the disk 1 in a direction to cancel the moment generated around the support point due to the weight of the disk 1 itself. The shapes of the pressing portion 9a and the disk mounting portion 5a are the same as those in the first embodiment.

  Also in the second embodiment, the disc tilt can be reduced with a simple configuration, and the recording and reproduction of signals can be ensured.

  Other configurations, operations, and effects are the same as those in the first embodiment although the description thereof is omitted.

(Embodiment 3)
As shown in FIG. 9, the third embodiment of the present invention is an information recording / reproducing apparatus for reproducing information recorded on the disk 1, and this information recording / reproducing apparatus includes the optical head 2, the disk drive device 30, and the detection. The circuit 32, the reproduction circuit 34, the tracking control circuit 36, the focus control circuit 38, and the like are main components. The information recording / reproducing apparatus may be configured to record information on the disc 1 and to reproduce the information recorded on the disc 1.

  Although not shown, the optical head 2 includes a laser light source, a beam shaper, a half mirror, an objective lens, an objective lens actuator, and the like. The detection circuit 32 generates a reproduction signal based on the reflected light emitted from the laser light source of the optical head 2 and reflected by the disk 1, and also generates a tracking error signal and a focus based on the branched light branched from the emitted light. Generate an error signal. The reproduction circuit 34 reproduces information recorded on the disc 1 based on the reproduction signal. The tracking control circuit 36 controls the optical head 2 so as to compensate the tracking error based on the tracking error signal. The focus control circuit 38 controls the optical head 2 so as to compensate for the focus error based on the focus error signal. Although the disk drive device 30 has the configuration described in the first embodiment, the configuration of the second embodiment may be used instead.

  Other configurations, operations, and effects are the same as those in the first embodiment although the description thereof is omitted.

1 is a perspective view showing a main part of an optical disk device to which a disk drive device according to Embodiment 1 of the present invention is applied. It is sectional drawing of the said disk drive device. (A) It is explanatory drawing for demonstrating the moment which acts on the disk hold | maintained at the disk drive device which concerns on this Embodiment 1. FIG. (B) It is explanatory drawing for demonstrating the moment which acts on the disk hold | maintained at the conventional disk drive device. (C) It is explanatory drawing for demonstrating the moment which acts on the disk hold | maintained at the disk tilt measuring machine. It is a characteristic view which shows the relationship between a clamping force and a disk tilt. It is a characteristic view showing the relationship between the moment ratio and the disc tilt. It is a perspective view of a pressing member. It is sectional drawing which expands and shows the press member vicinity. It is sectional drawing of the disk drive device concerning Embodiment 2 of this invention. It is a schematic block diagram of the information recording / reproducing apparatus which concerns on Embodiment 3 of this invention. It is a schematic sectional drawing of the conventional disk drive device. 1 is a schematic cross-sectional view of a disk drive device described in Patent Document 1. FIG.

Explanation of symbols

1 disk 1a center hole 5a disk mounting part 7 alignment ring 7a taper surface 9a pressing part

Claims (8)

A disk drive device for driving a disk,
A disk mounting portion that contacts the disk and rotates together with the disk;
Pressing the surface of the disc opposite to the disc mounting portion, and a pressing portion that rotates together with the disc,
The disk drive device in which the pressing unit and the disk mounting unit are set in a positional relationship in which a moment is generated in a direction that cancels a moment generated in the disk by the weight of the disk. A disk drive device for driving a disk,
A disk mounting portion that contacts the lower surface of the disk and rotates together with the disk;
A pressing portion that is disposed above the disc mounting portion and that presses the upper surface of the disc and rotates together with the disc;
The disk drive device, wherein the pressing portion is disposed on an inner peripheral side with respect to the disk mounting portion. A disk drive device for driving a disk,
A disk mounting portion that contacts the upper surface of the disk and rotates together with the disk;
A pressing portion that is disposed below the disc mounting portion and presses the lower surface of the disc to rotate together with the disc;
The disk drive device, wherein the disk mounting portion is disposed on an inner peripheral side with respect to the pressing portion. The disc is provided with a central hole,
Abutting on the peripheral edge of the central hole in the disk, and provided with an abutting part that rotates together with the disk,
4. The disk drive device according to claim 1, wherein the contact portion contacts the disk from the same side as the disk mounting portion with respect to the disk. 5. The abutting portion has a tapered surface that can abut on the peripheral edge of the center hole of the disc and is formed concentrically with the rotation axis of the disc,
The disk drive device according to claim 4, wherein the disk is centered by contacting the tapered surface with a peripheral edge of a center hole of the disk. The disk drive device according to any one of claims 1 to 5, wherein the pressing portion is formed in a plurality of protrusions arranged at intervals in the circumferential direction. The disk drive device according to claim 6, wherein the pressing portion is formed in a point contact shape in a radial cross section. A disk drive device according to any one of claims 1 to 7,
With an optical head,
An information recording / reproducing apparatus for reproducing information by irradiating the disk with the optical head while driving the disk with the disk driving apparatus.

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