JPH0550526U - Focus servo device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a focus servo device having a simple structure in which a distance between an optical disk and a head of a disk player is a regular distance within a predetermined range. [Structure] In a focus servo device of a disc player that records or reproduces information on or from the optical disc 1, when it is detected that the distance between the head 14 and the optical disc 1 is not within a predetermined range, the optical disc 1 is detected. The optical disk 1 is raised or lowered together with the turntable 2 which is rotationally driven, and the distance between the head 14 and the optical disk 1 is set within a predetermined range.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a focus servo device for setting an appropriate distance between an optical disc and a head for an optical disc having a shape outside the standard range.

[0002]

[Prior Art]

 A reproducing apparatus that optically reads information recorded as minute pits on an optical disc uses various servo mechanisms to accurately reproduce the recorded information.

That is, a focus servo mechanism that accurately focuses laser light emitted from an optical pickup device, which is a head, onto an optical disk, a tracking servo mechanism that accurately causes the laser light to follow a row of pits on the optical disk, It is equipped with a tilt servo mechanism that corrects the attitude of the optical pickup device with respect to the warp of the optical disk.

Therefore, in order to reproduce an optical disc having a shape within the range determined by the standard, information can be read without any trouble only by the above-mentioned servo mechanism.

However, since an optical disc is generally formed of a polycarbonate resin, the shape of the optical disc is out of the standard if the storage condition or the usage method of the optical disc is bad, and it is difficult to reproduce only by the servo mechanism described above. May be.

[0006] Therefore, there is a focus servo device newly equipped with a height servo mechanism for vertically moving the position of the optical pickup device itself in order to accurately reproduce such a nonstandard optical disc.

[0007]

In the above-mentioned conventional technique, by adding a height servo mechanism to the optical pickup device which is a head, the structure of the optical pickup device becomes complicated and the device becomes large in size. is there.

[0008]

[Means for Solving the Problems]

 The present invention, in a focus servo device of a disc player for recording or reproducing information on an optical disc, rotates the optical disc when it detects that the distance between the head and the optical disc is no longer within a predetermined range. The optical disk is raised or lowered together with the turntable to set the distance between the head and the optical disk within a predetermined range.

[0009]

[Action]

 According to the present invention, the distance between the optical disk and the head can be set to an appropriate distance within a predetermined range for an optical disc having a shape outside the standard range with a simple configuration.

[0010]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a state in which the optical disc 1 is placed on a tray (not shown), moved into the apparatus by horizontal loading means (not shown), and the optical disc 1 is clamped. 2 is the side view.

The optical disc 1 is sandwiched between a turntable 2 and a clamper 3. The turntable 2 is rotationally driven by a spindle motor 5 via a shaft 4 to rotate the optical disc 1. The spindle motor 5 is mounted on a mounting plate 6, and guide pins 7 provided on both sides of the mounting plate 6 are engaged with an inner groove 9 formed on two guide plates 8. .. A rack 10 is formed on each of the two guide plates 8, and two pinions 13 connected to a guide plate drive motor 11 by a drive shaft 12 are meshed with each other.

An optical pickup device 14, which is a head for irradiating the optical disc 1 with laser light to reproduce information recorded on the optical disc 1, is mounted on a support 15. A pinion 16 driven by a motor (not shown) is attached to the support base 15, and the pinion 16 meshes with a rack 19 formed on a rail 18 mounted on a chassis 17. Therefore, the optical pickup device 14 moves on the rail 18 along the guide shaft 20 between the inner circumference and the outer circumference of the optical disc 1 by driving the pinion 16 attached to the support base 15.

In order to hold the optical disc 1 between the turntable 2 and the clamper 3, the guide plate drive motor 11 moves the guide plate 8 and the guide pin 7 engaged with the guide groove 9 of the guide plate 8 is moved upward. The turn table 2 is raised together with the spindle motor 5 by guiding it in the direction, but the guide groove 9 with which the guide pin 7 is engaged has a shape as shown in FIG.

Here, by moving the guide plate 8 in the direction of arrow A, the guide pin 7 is moved from the lower end portion 91 of the guide groove 9 to the upper end portion 92, and the turntable 2 is raised. Further, the guide pin 7 is moved to the normal reproduction position 93 of the guide groove 9.

In this state, the spindle motor 5 rotates the turntable 2 to rotate the optical disc 1, and the optical pickup device 14 reproduces the information recorded on the optical disc 1. As shown in FIG. 4, before or during reproduction, the focus error signal detector 21 detects the focus error signal from the optical pickup device 14, and the focus servo circuit 22 creates the focus servo drive signal. A focus servo drive signal is applied to the moving coil 24 for moving the objective lens 23 of 14 to make the distance between the objective lens 23 and the optical disk 1 a proper distance, and further by moving the objective lens 23 up and down finely, The information is reproduced accurately by following the wobbling of. Further, with respect to the warp of the optical disc 1, the attitude of the optical pickup device 14 is changed by the tilt servo mechanism.

However, if the optical disc 1 has a shape within the normal standard range, the distance between the objective lens 23 and the optical disc 1 can be set to an appropriate distance by the focus servo mechanism described above. If it is deformed to the outside shape, the focus servo mechanism and tilt servo mechanism alone cannot handle it.

Therefore, as shown in FIG. 5, when the optical disc 1 is deformed to be convex downward beyond the standard range, the allowable range of the objective lens 23 being raised by the focus servo mechanism is exceeded. Therefore, as shown in FIG. 4, the height servo circuit 25 detects from the focus servo drive signal that the objective lens 23 has risen to a certain level, and the height servo circuit 25 creates a height servo drive signal to drive the guide plate drive motor. 11 is applied.

Then, the guide plate 8 shown in FIG. 3 is moved in the direction of the arrow B, the guide pin 7 is moved to the disc lowering position 94, and the optical disc 1 is lowered slightly together with the turntable 2, the clamper 3, and the spindle motor 5. The objective lens 23 is set within an allowable range in which it can be raised, and the focus servo mechanism allows the distance between the objective lens 23 and the optical disk 1 to be an appropriate distance within a predetermined range.

When the optical disc 1 is deformed in a convex shape exceeding the standard range, the guide plate 8 shown in FIG. 3 is moved in the direction of arrow A to move the guide pin 7 to the disc raising position 95. The optical disc 1 is moved up slightly together with the turntable 2, the clamper 3 and the spindle motor 5, and is set within an allowable range in which the objective lens 23 can be lowered. Make sure the distance is within the range.

Although the focus servo device is provided in the loading mechanism of the optical disc in the present embodiment, the focus servo device may be provided independently of the loading mechanism. Furthermore, the focus servo device of the present embodiment is Although the optical disk is moved up and down by sliding the guide plate, other methods may be used to move the optical disk up and down. Further, it is needless to say that the present invention is not limited to the reproducing device but can be applied to the recording device and can be used for magneto-optical and the like.

[0021]

[Effect of the device]

 According to the present invention, since the distance between the optical disk and the head can be set to an appropriate distance within a predetermined range, it is possible to accurately reproduce or record information even on an optical disk having a shape outside the standard range. Since the focus servo device that can be used has a simple structure, it is possible to equip the focus servo device without increasing the size of the device.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a front view showing an embodiment of the present invention.

FIG. 3 is a detailed view of a guide plate according to an embodiment of the present invention.

FIG. 4 is a block diagram of an embodiment of the present invention.

FIG. 5 is a diagram showing a state when an optical disc having a shape out of the standard range is mounted in the embodiment of the present invention.

[Explanation of symbols]

 1 optical disk 2 turntable 14 optical pickup device (head)

Claims (1)

[Scope of utility model registration request] 1. A focus servo device of a disc player for recording or reproducing information on an optical disc, when detecting that the distance between the head and the optical disc is no longer within a predetermined range, the optical disc is detected. A focus servo apparatus, characterized in that the optical disk is raised or lowered together with a turntable that is rotationally driven so that a distance between the head and the optical disk falls within a predetermined range.