JPH0454296B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is a method for recording information signals such as video signals by irradiating a laser beam emitted from a laser oscillator of an optical pickup onto an optical disk on which information signals such as video signals are recorded. The present invention relates to an optical player for reading and reproducing information, and in particular, is capable of adjusting the inclination in the tangential direction of the optical axis of incidence of the laser beam with respect to the recording surface of the optical disk.

<Background art and its problems> An optical player has a disk table that is integrally attached to a center spindle that is rotationally driven by a spindle drive motor, and an optical disk is mounted on this disk table. While rotating at a constant speed in synchronization with the table, an optical pickup with a built-in laser oscillator is rotated from the inner circumference to the outer circumference of the optical disk in the normal direction of the recording track formed on the optical disk (optical disk A laser beam emitted from the laser oscillator is irradiated perpendicularly from the lower surface of the optical disk to track a recording track, and a predetermined information signal recorded on the recording track is tracked. is configured to read and play.

The main body of the optical pickup mentioned above is guided by two parallel guide members and sent in the radial direction of the optical disk, but if the incident optical axis of the laser beam is tangential with respect to the recording surface of the optical disk. If it is tilted in this direction, the resolution of the object formed by the video signal will deteriorate, which will seriously affect the characteristics.

By the way, experimental results have shown that when the inclination of the optical axis exceeds 0.6°, the deterioration of the resolution becomes noticeable. Therefore, the inclination of the optical axis must be kept within 0.6°. However, since the optical axis tilt angle (0.6°) mentioned above includes the warpage of the optical disk, if we ignore this disk warpage, the optical axis angle of the laser beam mentioned above will be affected by the optical axis angle other than the optical disk. The skew of the parts (center spindle, objective lens of optical pickup, etc.) that affect the
It is necessary to keep it below about 0.1°.

However, the structure of the optical player is complex, and even if the precision of parts such as the center spindle and the objective lens of the optical pickup is improved, it is difficult to increase the mounting precision of each part, and the inclination of each part is set to 0.1°. It is almost impossible to keep it below that level. Therefore, the reality is that there is a need for an adjusting device that can adjust and correct the inclination of the optical axis.

<Object of the Invention> The present invention has been proposed in view of the above circumstances, and provides an optical system capable of adjusting the inclination of the incident optical axis of a laser beam in the tangential direction with respect to the disk surface of an optical disk. The purpose is to provide players.

<Summary of the Invention> In order to achieve the above object, the present invention provides an optical pickup body in which an optical pickup main body is guided by two parallel guide members and sent to an optical disk in the radial direction of the disk. In an optical player equipped with a pick-up, a guided portion in contact with one side of the parallel guide member is provided at a position offset from a rotation center of an adjustment member rotatably supported by the optical pick-up main body, and a disc The inclination of the optical axis in the tangential direction of the detection beam irradiated onto the disk surface is determined by driving the driving means with the output of a detection device that detects the inclination of the optical axis in the tangential direction with respect to the disk surface and rotating the adjustment member. The invention is characterized in that it is equipped with a tangential shift servo device adapted to adjust the tangential shift.

<Example> Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic plan view showing the main parts of an optical player according to the present invention. This optical player has a chassis 2 that is fitted into an exterior cabinet 1, and a spindle drive motor 3 constituting a disk drive device is attached to the lower surface of the chassis 2, approximately at the center thereof. . A center spindle 4 is directly connected to the output shaft side of the spindle drive motor 3 coaxially with the output shaft. A disk table 6 on which an optical disk 5 is mounted is attached to a portion of the center spindle 4 that projects toward the upper surface of the chassis 2. The optical disk 5 mounted on the disk table 6 is rotated at a constant speed by the rotational drive of the spindle drive motor 3.

Further, on the chassis 2, there is an optical pickup 7 which uses the chassis 2 as a support base to track recording tracks of the optical disk 5 placed on the disk table 6 using a laser beam. A light-transmitting objective lens 8 is disposed facing the optical disk 5. This optical pickup 7 is fed by a feeding mechanism 9 in the radial direction of the disk 5 (in the direction of arrow A in FIG. 1).

That is, as the disk 5 is rotated, the optical pickup 7 is sent in the radial direction of the disk 5, and the laser beam is irradiated perpendicularly to the recording surface from the lower surface of the disk 5. The recording track is tracked, and the information signal (video signal) recorded on the recording track is read and reproduced.

The optical pickup main body 10 of the optical pickup 7 is guided in its feeding by two parallel guide shafts 11 and 12 fixedly attached to the chassis 2 so as to face each other in parallel.

As shown in FIGS. 2, 3, and 4, the optical pickup main body 10 includes a laser oscillator that emits a laser beam, and an objective lens 8 in the tracking direction of the optical disk 5 and in the focus direction of the laser beam. A biaxial drive device 13 that drives and displaces the laser beam in two axial directions, and a reproduction signal control that controls the laser beam to parallel light or controls the traveling direction of the laser beam reflected from the recording surface of the optical disk 5 and detects its output. a first block 15 in which a photodetector 14 is incorporated; and a tangential shifter integrally formed in parallel with this block 15 for detecting the inclination of the incident optical axis of the laser beam in the tangential direction with respect to the optical disk 5. and a second block 17 in which a servo device 16 (see FIG. 5) is incorporated.

One shaft 11 of the parallel guide shafts 11 and 12 is located outside the first block 15 and has a rolling bearing (hereinafter referred to as
It's called a bearing. ) 18 and 19, and the other shaft 12 is fitted into a bearing hole 20 formed through the second block 17.

The lower bearing 18 of each of the bearings 18 and 19 is rotatably supported at the tip of a link 21 rotatably attached to the outer surface of the first block 15, and the lower bearing 18 is rotatably supported at the tip of a link 21 which is rotatably attached to the outer surface of the first block 15. Tension spring 22 biasing in the counterclockwise direction
The first shaft 11 is placed in a state of elastic engagement with the first shaft 11.

Further, the upper bearing 19 is attached to a worm gear 23 serving as an adjustment member rotatably attached to the outer surface of the first block 15, with its rotation center X ₁
is rotatably supported via a support shaft 24 so as to be eccentric from the rotation center X ₂ of the worm gear 23 .

The worm gear 23 is a worm gear 2 attached to the output shaft of a drive motor 25 that is drive-controlled by the tangential shift servo device 16.
6 so that it can be rotated in one direction.

That is, by rotating the bearing 19 around the rotation center X ₂ of the worm gear 23 as the worm gear 23 is rotated, the optical pick-up 7 is rotated around the other shaft 12 of the parallel guide shafts 11 and 12. As a result, the inclination of the incident optical axis of the laser beam in the tangential direction with respect to the recording surface of the optical disk 5 can be adjusted.

As shown in FIG. 5, the tangential ski servo device 16 directs a detection beam from a light source 27 such as a light emitting diode (LED) through a lens 28 and a beam splitter 29 perpendicularly to the recording surface of the optical disk 5. At the same time, the detection beam that is reflected from the recording surface and returned is sent to the beam splitter 29.
It is reflected at an angle of 90 degrees and projected onto a tangential ski user servo detector 30.

The detector 30 has the function of detecting the light intensity distribution of the detection beam reflected from the recording surface of the optical disk 5, and is arranged in the tangential direction (in FIG. It has two light receiving areas 31 and 32 divided into two in the direction of arrow T).

Then, as shown in FIG.
The difference between the detection outputs of each region 31 and 32 of 0 is subtracted by a subtracter 3.
3 and supplies the control signal to the drive motor 25 via the amplifier 34 to control the drive of the motor 25.

That is, the mounting precision of parts such as the center spindle 4 and the objective lens 8 of the optical pickup 7 is low, and the incident optical axis of the laser beam irradiated onto the recording surface of the optical disk 5 through the objective lens 8 during playback is not aligned with the recording surface. When the recording surface is tilted in the tangential direction with respect to the surface, the optical axis of incidence of the detection beam of the tangential ski servo device 16 on the recording surface also tilts in the tangential direction following the tilt. When the optical axis of incidence of this detection beam with respect to the recording surface is tilted in the tangential direction, the amount of light of the detection beam projected onto the tangential ski servo detector 30 is biased toward one of the regions 31 and 32, resulting in a detection output. It makes a difference.

In this way, when a difference occurs in the detection outputs of the detector 30, a control signal is supplied to the drive motor 25, and the optical pickup 7 is operated so that the incident optical axis of the laser beam is centered on the other shaft 12, and the incident optical axis of the laser beam is aligned with the recording area of the optical disk 5. Automatically rotates in the direction perpendicular to the surface.

Thus, according to the above embodiment, the optical disk 5 of the laser beam emitted from the laser oscillator
Components related to the tangential tilt of the incident optical axis with respect to the recording surface (center spindle 4,
Even if the installation accuracy of the objective lens (8, etc.) is low and the incident optical axis of the laser beam is tilted in the tangential direction, the inclination of the incident optical axis is adjusted so that the laser beam is irradiated perpendicularly to the recording surface of the optical disk 5. You can play it back while editing it. Therefore, a reproduced image with excellent resolution can be obtained. Furthermore, the mounting accuracy of parts such as the center spindle 4 and the objective lens 8 may be rough, which leads to lower costs.

<Application Examples> The present invention is useful for optical players that record video signals on optical discs, and is also useful for optical players that record and/or reproduce musical sound signals on optical discs. It is something.
Note that when the present invention is applied to an optical player that reproduces musical tone signals, it is possible to obtain musical tones with no waveform distortion and excellent sound quality.

<Effects of the Invention> As described above, according to the present invention, components related to the inclination in the tangential direction of the optical axis of incidence of the laser beam irradiated onto the disk surface of the optical disk from the optical pickup with respect to the disk surface of the optical disk, e.g. Even if the installation accuracy of the center spindle, the objective lens of the optical pickup, etc. is low, and the incident optical axis of the laser beam is tilted in the tangential direction, the incident optical axis should be adjusted so that the laser beam is irradiated perpendicularly to the disk surface of the optical disk. The optical pickup can be sent in the radial direction of the optical disk while adjusting and correcting the inclination of the optical disk.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing an embodiment of the present invention;
Figure 2 is a front view of the optical pickup section, Figure 3 is a front view of the optical pickup section;
4 is a side view thereof, FIG. 5 is an enlarged perspective view showing the configuration of the tangential ski servo device, and FIG. 6 is a partially cutaway plan view of the tangential ski servo device. FIG. 2 is a circuit diagram showing the configuration of a signal processing section. 5...Optical disk, 7...Optical pickup, 1
0... Optical pickup body, 11, 12... Parallel guide shaft, 16... Tangential skier servo device, 18, 19... Bearing, 23... Worm gear, 25... Drive motor, 26... Worm,
30...Detector for tanzenial ski user servo.

Claims (1)

[Claims] 1. In an optical player equipped with an optical pickup in which the optical pickup main body is guided by two parallel guide members and sent to an optical disk in the radial direction of the disk, one of the parallel guide members The contacting guided portion is provided at a position offset from the center of rotation of the adjusting member rotatably supported by the optical pickup main body, and the tangential direction of the optical axis of the detection beam irradiated onto the disk surface with respect to the disk surface is provided. a tangential ski servo device configured to adjust the inclination of the optical axis in the tangential direction by driving a driving means with the output of a detection device for detecting the inclination of the optical axis to rotate the adjusting member. An optical player.