JPH10239106A - Optical disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin optical disk device that can accurately detect the rotational angle of a rotating shaft. SOLUTION: The optical disk driving device is constituted of a spindle motor 15, which rotates while holding an optical disk, an optical pickup 17, which reproduces information from the optical disk, a feed motor 25 which moves the pickup 17 in the radial direction of the optical disk, a rotational angle indicating member 26 having substantially a cylindrical surface, which is provided on a rotating shaft and on which a scale is marked correspondingly to the rotational angle of the rotating shaft, and an optical sensor 27, which reads the scale of the member 26. Therefore, the thickness of the optical disk driving device can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk drive for reading data from an optical disk such as a CD-ROM or a magneto-optical disk or writing data to the optical disk, and more particularly to an encoder for detecting a rotation angle. It is about.

[0002]

2. Description of the Related Art In recent years, an optical disk drive for reading data from an optical disk such as a CD-ROM or a magneto-optical disk or writing data to the optical disk has been rapidly increasing in demand as a peripheral device of a computer. This optical disk drive is rapidly becoming smaller and thinner for use in a notebook personal computer, and its access speed is remarkably improved.

The configuration of a conventional optical disk drive will be described. FIG. 4 is a perspective view of a conventional optical disk drive, and FIG. 5 is an enlarged view of the rotation angle indicating member 13 of FIG.
Reference numeral 1 denotes a spindle motor, which has a turntable 1 a that holds and rotates the optical disk 2 and is fixed to a frame 3. Reference numeral 4 denotes an optical pickup for irradiating the optical disk with a laser beam from a lens 4a and reproducing information by the reflected light, and reference numeral 5 denotes a feed shaft, which is rotatably provided on the frame 3 and is fitted to the optical pickup 4 to The optical pickup 4 is guided in the radial direction of the optical disk. A guide shaft 6 is fixed on the frame 3 and guides the optical pickup 4 together with the feed shaft 5 in the radial direction of the optical disk. A spiral groove 5 a is provided on the outer peripheral surface of the feed shaft 5, a rack 7 having a projection engaging with the groove 5 a is provided on a leaf spring 8, and one end of the leaf spring 8 is fixed to the optical pickup 4. The rack 7 is pressed and urged into the groove 5a and meshes without play. Reference numeral 9 denotes a feed gear fixed to the feed shaft 5, which is connected to a pinion gear 11 via a reduction gear 10 rotatably supported on the frame 3. Reference numeral 12 denotes a feed motor, on which a pinion gear 11 and a disk-shaped rotation angle indicating member 13 having a slit 13a are press-fitted and fixed to a rotation shaft 12a. An optical sensor 14 having a light emitting unit and a light receiving unit is attached to the frame 3 so as to sandwich the rotation angle indicating member 13.

[0004] The operation of the conventional example in the above configuration will be described. It is assumed that the optical pickup 4 is waiting at a predetermined position on the disk. When an instruction to read data from a predetermined track is given, a voltage is applied to the feed motor 12 to move the optical pickup 4 to a desired position. At this time, the rotation angle indicating member 13 provided on the rotation shaft 12a rotates, and the slit passes between the light emitting portion and the light receiving portion, so that the output voltage of the optical sensor 14 repeatedly changes between high and low. Feed motor 12 from timing
Detect the rotation speed of. The moving speed of the optical pickup 4 is calculated from this and the reduction ratio, and the optical pickup 4 can be moved with an optimum acceleration / deceleration profile, so that access can be speeded up. In this case, as the number of slits per rotation of the feed motor 12 increases, the detection accuracy of the moving speed of the optical pickup 4 increases, which leads to an increase in access speed.

[0005]

However, in such a conventional configuration, the size of the disc-shaped rotation angle indicating member 13 is one obstacle to a reduction in thickness. This is because, as is apparent from FIG. 5, the disc-shaped rotation angle indicating member 13 needs a dimension L outside the detection center. In the method of reducing the diameter R of the detection position of the rotation angle indicating member, it is necessary to reduce the width of the slit 13a in order to maintain the number of slits 13a per rotation. When the SN ratio is deteriorated and the rotation speed is increased, the slit 13a may not be detected.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a thin optical disk drive capable of accurately detecting a rotation angle.

[0007]

According to the present invention, in order to achieve the above object, a rotation angle indicating member is arranged coaxially with a rotation shaft of a feed motor as a rotation driving source, and a scale corresponding to the rotation angle is rotated. It had a configuration having a substantially cylindrical surface attached parallel to the axis.

[0008]

According to the present invention, the rotation angle indicating member does not require a size outside the detection center and the thickness of the optical disk drive can be reduced.

An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.

FIG. 1 is a perspective view of an optical disk drive according to an embodiment of the present invention.
15a is a turntable, 16 is a frame, 17 is an optical pickup, 17a is a lens, 18 is a feed shaft, 1
8a is a groove of a feed shaft, 19 is a guy shaft, 20 is a rack, 20a is a protrusion of a rack, 21 is a leaf spring, 22 is a feed gear, 23 is a reduction gear, 24 is a pinion gear, and 25 is a pinion gear.
Is a feed motor, 25a is a rotation axis of the feed motor,
Since these are the same as the configuration of the conventional example, detailed description will be omitted.

A rotation angle indicating member 26 having a cylindrical surface and a long slit 26a substantially parallel to the rotation axis direction is press-fitted and fixed to a rotation shaft 25a of the feed motor 25, and a light emitting unit and a light receiving unit sandwich the cylindrical surface. Is mounted on the frame 16. FIG. 2 shows a rotation angle indicating member 2
6 is a detailed view of the optical sensor 6 and the optical sensor 27. The distance from the axis center of the rotating shaft 25a to the detection center is R as in the conventional example, and the dimension of the slit 26a is also the same.

As described above, according to the optical disk drive of the embodiment of the present invention, since there is no unnecessary configuration in the outer peripheral direction from the detection center, the thickness of the optical disk drive can be reduced.

FIG. 3 is a detailed view of a rotation angle indicating member 26 and a light sensor 27 according to another embodiment of the present invention. In FIG. 3, instead of a slit, a scale composed of a portion having a high reflectivity and a portion having a low reflectivity with respect to an electromagnetic wave having a specific wavelength is provided on the approximately cylindrical surface of the rotation angle indicating member 26 (for infrared rays, for example). Alternatively, a configuration may be adopted in which this is detected by an infrared sensor integrated with the light receiving unit and the light emitting unit.

The scale portion may be made of a magnetized material, and the detection may be performed using a magnetoresistive element or the like.

[0015]

As is apparent from the above description, according to the present invention, a rotation angle indicating member is provided on a rotation shaft of a feed motor as a rotation driving source, and a scale corresponding to the rotation angle is provided in parallel with the rotation shaft. With the configuration in which the attached substantially cylindrical surface is arranged coaxially with the rotation axis, the rotation angle indicating member does not need an unnecessary portion outside the detection center, and the optical disk drive can be made thinner.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical disk drive according to an embodiment of the present invention.

FIG. 2 is a detailed view of a rotation angle indicating member 26 and an optical sensor 27;

FIG. 3 is a detailed view of a rotation angle indicating member 26 and a light sensor 27 according to another embodiment of the present invention.

FIG. 4 is a perspective view of a conventional optical disk drive.

FIG. 5 is an enlarged view of a rotation angle indicating member of FIG. 4;

[Explanation of symbols]

 1, 15 Spindle motor 1a, 15a Turntable 3, 16 Frame 4, 17 Optical pickup 4a, 17a Lens 5, 18 Feed shaft 5a, 18a Groove 6, 19 Guide shaft 7, 20 Rack 8, 21 Leaf spring 12, 25 Feed Motor 12a, 25a Rotary shaft 13, 26 Rotation angle indicating member 13a, 26a Slit 14, 27 Optical sensor

Claims (4)

[Claims] An optical pickup for reproducing information from an optical disk, a rotary drive source for moving the optical pickup in a radial direction of the optical disk, and a scale arranged coaxially with a rotation axis of the rotary drive source and corresponding to a rotation angle. An optical disk drive comprising: a rotation angle indicating member having a substantially cylindrical surface with a mark; and a detecting means for reading a scale of the rotation angle indicating member. 2. The rotation angle indicating member according to claim 1, wherein a scale corresponding to a rotation angle given to said substantially cylindrical surface is constituted by a plurality of openings substantially parallel to said rotation axis. An optical disk drive as described in the above. 3. A scale corresponding to a rotation angle given to the substantially cylindrical surface of the rotation angle indicating member has a portion having a high reflectance and a portion having a low reflectance with respect to an electromagnetic wave having a specific wavelength. The optical disk drive according to claim 1, wherein: 4. The optical disk drive according to claim 1, wherein a scale corresponding to a rotation angle of the rotation angle indicating member provided on the substantially cylindrical surface is made of a magnetic material.