JPS60143447A - Optical disk player - Google Patents

Abstract

PURPOSE:To move the moving neutral point of an objective in the direction of the optical axis in accordance with the inclination of a disk, by supporting an optical pickup in such a way that its rotation supporting shaft is put between the objective and rotating center of the disk and the pickup can be rotated freely. CONSTITUTION:When a disk 11 is inclined downward and a skew is produced, a skew controlling signal corresponding to a skew detect signal generated based on the skew detected by a skew detecting means 24 is sent from a skew controlling signal generating section to a motor 32 and a gear 31 is rotated clockwise. As a result, an optical block 20 and optical pickup 23 are rorated and displaced in the direction shown by the arrow (b) around a supporting shaft 13 and an optical beam is controlled so that its optical axis OB intersects the recording surface 11a of the disk 11 at right angles. Therefore, reduction of moving strokes of an objective by focussing control can be suppressed under the condition where the disk is inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to adjusting the optical axis of the reading light beam incident on the recording surface of the optical disc, which is called skew correction control, when reading 1n information from an optical disc on which information is recorded. Background technology and problems related to optical disc players with directional control A recording trunk is formed by the arrangement of pits, and information is recorded on the optical disc. In an optical disc player that reproduces information, when reading information from a disc, focus control is performed to make the light beam enter the recording surface of the rotating optical disc in an appropriate focused state, and the light beam is directed to the recording track of the optical disc. In addition to tracking control for proper tracking, due to the inclination of the optical disc, etc., the angle of the incident light beam relative to the line perpendicular to the recording surface of the optical disc at the incident position of the light beam that is incident on the recording surface of the optical disc may be When a tilt of the optical axis (hereinafter referred to as skew) occurs, the direction of the optical axis of the light beam is changed to eliminate the skew. It has been proposed to perform skew correction control so that the leading axes of the laser beams are incident at right angles to each other.

In already proposed optical disc players in which such skew correction control is performed, a disc J is shown in FIG.

The optical pink-up 3, which has an objective lens 2 that focuses a light beam on a recording surface 1a and performs an information reading operation, is rotated by a feeding means (not shown) at a rotation fulcrum X on the optical axis of the objective lens 2. It is supported freely, and during information reading operation,
It is made to move in the radial direction of the rotating disk 1. When the disc 1 is installed in the disc mounting part 4, it is not placed in a horizontal position as shown by the solid line, but is tilted at an angle θ with respect to the horizontal position as shown by the dashed line. When skew occurs, the entire optical pink-up 3 is rotated by an angle θ in the direction of arrow a about the rotation fulcrum X, and the light beam incident on the disk 1 is The axis OB is controlled to be perpendicular to the recording surface 1a of the disk 1 at the incident point.

By the way, in the focus control in such an optical disc player, the objective lens 2 is moved in a direction toward or away from the recording surface 1a of the disc 1 around its moving neutral point, and the objective lens 2 is moved toward or away from the recording surface 1a of the disc 1. An operation is performed in which the distance between the lens 2 and the recording surface 1a of the disk 1 is kept constant and the light beam is made to enter the recording surface 1a of the disk 1 in a proper focused state. Therefore, the objective lens 2 is
Within the optical pink-up 3, it is possible to move with a stroke of, for example, about ±2 mm around the neutral point of movement. However, when the disk 1 is tilted as shown by the dashed line, the objective lens 2 is constantly moved from the neutral point by the deflection δ of the disk 1. , there is a problem that there is no margin in the movement stroke for focus control. Furthermore, the deflection δ of the disk 1 is
If it exceeds a predetermined value, in this case 2 mm, there is a risk that proper focus control will not be performed and information reading will not be possible.

Therefore, when the disk 1 is tilted and a skew occurs, the neutral point of the movement of the objective lens 2 in the optical pickup 3 is moved in accordance with the tilt of the disk 1, and the objective lens 2 is moved during skew correction. It is desirable to position the object lens 2 as close to the neutral point of the movement as possible to suppress a decrease in the movement stroke of the objective lens 2.

However, in an optical disc player equipped with an optical pickup 3 supported as shown in FIG. However, there is a disadvantage that the neutral point of movement of the objective lens 2 within the optical pickup 3 hardly moves. In order to obtain such movement of the moving neutral point of the objective lens 2, the optical pickup 3 is
It is conceivable to move the rotational fulcrum X of the optical pickup 3 according to the rotation of the disk 1, but in this case, there is a problem that the support mechanism of the optical pickup 3 and its control system become extremely complicated.

Purpose of the Invention In view of the above, the present invention has a simple structure, and provides a mechanism for moving the neutral point of the objective lens in its front axis direction in accordance with the inclination of the disk when skew correction control is performed. The purpose of the present invention is to provide an optical disc player with a

Summary of the Invention An optical disc player according to the present invention includes an optical pickup that moves in the radial direction of a rotating disc and makes a light beam incident on the recording surface of the disc through an objective lens. A rotation support shaft is placed between the center of rotation of the disk and is rotatably supported, and the disk is rotated so as to be close to the recording surface of the disk or away from the recording surface of the disk, The incident angle of the light beam on the recording surface of the disk is controlled. By doing this, with a relatively simple configuration, the neutral point of movement of the objective lens in the front axis direction can be moved in accordance with the inclination of the disk during skew correction control, and the movement within the optical pink-up can be adjusted. It is possible to suppress a decrease in the movement stalk of the objective lens.

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

2 and 3 show essential parts of an example of an optical disc player according to the present invention. In this example, a feed block 1
0 is provided, which is the disk 11 to be rotated.
It is slidably attached to a guide shaft 12 arranged to extend in the radial direction (FIG. 3). The feed block 10 is moved along a guide shaft 12 by being driven by a feed drive means (not shown).

In such a feed block 10, a support shaft 13 is connected to a guide shaft 12.
It is fixed in a direction perpendicular to .

An optical block 20 is rotatably attached to this support shaft 13. That is, the optical block 20 has
Two arm portions 21 and 22 are provided, and the support shaft 13 is inserted into the support holes 21a and 22a provided in the arm portions 21 and 22, respectively, so that the optical block 20 can It is designed to be able to rotate around three axes 13 as rotation centers. Here, the support shaft 13 is placed at a position between an objective lens 25 disposed within an optical pickup 23, which will be described later, and the rotational center of the disk 11.

In the optical block 20, an optical pickup 23 for reading information from the recording surface 11a of the disk 11 and a skew detection means 24 are installed.

The optical pink-up 23 is the recording surface 11a of the disk 11.
It is composed of various optical members, including an objective lens 25 that focuses a light beam having an optical axis OB on the top.
A light beam is made incident on the recording surface 11a of the disk 11, and the light beam is directed to the recording surface 11a of the disk 11.
It is designed to read information by detecting the return light from the sensor.

A plate 30 is arranged between the feed block 10 and the optical block 20. This plate body 30 is provided with an attachment hole 30a through which the support shaft 13 is inserted, and a gear 31 is attached to the surface facing the optical block 20. The rotation of an x1 motor 32 as shown in FIG. 3 is transmitted to the gear 31 via a worm gear 33 and a reduction gear group 34. The motor 32 is adapted to operate based on a skew control signal from a skew control signal generator (not shown), and this skew control signal is adapted to operate based on a skew detected by the skew detection means 24. Since the gear 31 is obtained by the motor 32
Therefore, the rotation is driven according to the degree of skew occurring at that time.

A roller 35 is attached to the gear 31.

As shown in FIG. 3, this roller 35 supports the optical block 20 by coming into contact with a boss 26 provided on the side surface of the optical block 20. That is, the optical block 20,
Due to the spring 27 stretched between the feed block lO,
Although it is pushed in the counterclockwise direction in FIG. 3, the boss 26 provided on the side surface abuts against the roller 35, thereby restricting the rotation. For example, the motor 32
When the gear 31 is rotated in the clockwise direction in FIG. 3, the optical block 20 and therefore the optical pink-up 23 are rotated in the counterclockwise direction in FIG. When the motor 32 rotates the gear 31 in the counterclockwise direction in FIG. 3, the optical pink-up 23 rotates in the clockwise direction in FIG. It will rotate to. Note that the plate body 30 is secured to the locking piece 37 by a shock-reducing spring 36 stretched between the plate body 30 and the feed block 10.
is connected to the feed block 10 in a state where it is brought into contact with the lower surface of the feed block 10.

Under such a configuration, as shown in FIG. 3, the disk 11 is not placed in a horizontal position as shown by the solid line, but is tilted downward as shown by the dashed line and is not skewed. is occurring, a skew control signal corresponding to the skew detection signal obtained based on the skew detected by the skew detection means 24 is sent from the skew control signal generating section to the motor 32, This results in
The gear 31 is rotationally driven in the clockwise direction in FIG. As a result, the optical block 20, and thus the optical pickup 23, is rotated about the support shaft 13 in the direction already shown by the arrow in FIG. Control is performed so that the optical axis OB is perpendicular to the recording surface 11a of the disk 11, that is, so that the incident angle of the light beam on the recording surface 11a of the disk 11 is zero. Here, in order to make this situation easier to understand, this will be explained using FIG. 4, which corresponds to FIG. 1. The disk is moved from the position shown by the solid line to the position shown by the dashed-dotted line as the rotation center of the rotation support shaft X" (corresponding to the center of the support shaft 13) placed between the center of the For example, let the distance between the pivot shaft X'' and the center of the objective lens 25 be L, and the angle with respect to the horizontal position of the disk 11, that is, the inclination angle. If θ is
The neutral point of movement of the objective lens 25 in the optical pickup 23 moves in a direction away from the disk 11 by approximately L-tan θ. Also, although not shown here,
Contrary to the above case, disk 11 is 1. When the optical pickup 23 is tilted at an angle of inclination θ such that it is above the horizontal position, the optical pickup 23 rotates in a direction approaching the disk 11 about the rotation axis X'' as the rotation center. The neutral point of movement of the objective lens 25 moves in a direction approaching the disk 11 by approximately L-tan θ.Thereby, in a state where focus control is performed,
The objective lens 25 is positioned 5 closer to the moving neutral point by .jan θ than in the case of the optical pickup 3 shown in FIG.

In the above example, the pivot shaft of the optical pickup is provided on the upper side of the optical pickup, close to the disk, but the pivot shaft may be provided on the lower side of the optical pickup. In short, the pivot shaft of the optical pink-up may be placed between the objective lens and the center of rotation of the disk.

Effects of the Invention As is clear from the above explanation, according to the optical disc player according to the present invention, skew correction control is performed using a circuit in which the optical pickup is placed between the objective lens and the center of rotation of the disc. Since this is performed by rotating the moving support shaft as the center of rotation, the neutral point of movement of the objective lens in the direction of its optical axis is moved in accordance with the inclination of the disk. As a result, focus control when the disk is tilted around f is performed with the objective lens positioned close to its moving neutral point, and the focus of the objective lens when the disk is tilted. It is possible to suppress a decrease in movement stroke during control. Moreover, the above-mentioned advantages can be obtained with a relatively simple configuration, without the disadvantage of causing a significant increase in costs.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining skew correction control in an optical disc player that has already been proposed, and FIG. 2 is an exploded perspective view showing essential parts of an example of an optical disc player according to the present invention. Figure 3 is a schematic sectional view of the main part shown in Figure 2 along the line ■-■ in Figure 2, and Figure 4 is the
FIG. 3 is a diagram used to explain the operation of main parts shown in the figure. In the figure, 11 is a disk, 13 is a spindle, 20 is an optical block, 21 and 22 are arms, 23 is an optical pickup, 2
4 is a skew detection means, 25 is an objective lens, 26 is a boss, 31 is a gear, and 35 is a roller. Figure 3 Figure 4

Claims (1)

[Claims] An optical pink-up, which moves in the radial direction of the rotated disk and allows a light beam to enter the surface of the disk through the objective lens, is rotated between the objective lens and the center of rotation of the disk. A moving support shaft is placed and rotatably supported, and is rotated so as to be close to or away from the surface of the disk, thereby controlling the incident angle of the light beam on the surface of the disk. An optical disc player designed to