JPS61177675A - Optical disk player - Google Patents

Abstract

PURPOSE:To discriminate correctly the diameter of a disk by irradiating the light of the disk with the optical system for detecting the skew and the optical system for recording and reproducing provided at the optical block shifted in the radial direction of the disk and detecting the reflecting light with these detecting elements of the optical system. CONSTITUTION:At an optical block 8, the first optical system 6 for detecting the skew and the second optical system 7 are placed. The optical block 8 is shifted along a guide shaft 9 in the radial direction [the (a) direction of an arrow] from the inner circumference position of static large, medium and small disks 1, 2 and 3. On the other hand, the light of a light emitting element 12 of the optical system 6 is projected through a guide shaft 9 to disks 1-3, and the reflecting light is detected with a detecting element 13. By the position where the reflecting light from the disks 1-3 is dissipated, the diameter of the disks 1-3 are correctly detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical disc player that records and plays data on a disc using, for example, a laser beam.

[Summary of the invention]

The present invention provides an optical disc player in which a first optical system provided on an optical block that is moved in the radial direction of the disc detects the skew of the disc, and a second optical system performs recording and reproduction on the disc. , the optical block is moved in the radial direction of the disk and the first
The optical system or the second optical system irradiates the disc with light, and the first optical system or the second optical system detects the presence or absence of the reflected light, thereby selectively mounting discs with different diameters. This makes it possible to determine the diameter of a disc with high accuracy without the need for additional special detection means.

[Conventional technology]

Conventionally, in this type of optical disk player, a method for determining the size of the disk was disclosed in Japanese Patent Application Laid-Open No. 57-21048.
There is a publication No. 0.

This takes advantage of the fact that the moment of inertia of the disk is proportional to the square of the radius of the disk, and that the rise time of the motor that drives the disk to rotate differs depending on the difference in this moment of inertia. The size of the disc is detected by comparing the time with a predetermined reference time.

There is a detection circuit that detects that the motor has reached a predetermined rotation speed and generates an output, a timer that produces a predetermined reference time, and a motor start-up time and reference time based on the output of the detection circuit and the output of the timer. A determination circuit is provided to determine the size of the disk by comparing the time with the reference time.For example, if the motor start-up time is longer than the reference time, it is determined that the disk is large, and conversely, if it is smaller, it is determined that the disk is small. is determined.

Another method is to place a plurality of sensors, such as photocouplers, below the mounting position of the disc in accordance with the size of the disc, and use the photocoupler at a position corresponding to the size of the mounted disc to There is one that detects the size of the disk.

[Problem that the invention seeks to solve]

However, the technique disclosed in Japanese Patent Application Laid-Open No. 57-210480 detects the rise time until the motor reaches a predetermined number of revolutions, so if the disc slips on the turntable, The rise time until the rotational speed is reached changes, and even a large disk is likely to malfunction in that it is determined to be a small disk.

In addition, in the case where multiple sensors are arranged according to the size of the disk, the number of sensors corresponding to the size of the disk must be specially provided.
This resulted in high costs.

Therefore, the present invention makes it possible to determine the diameters of selectively mounted disks having different diameters with great accuracy without providing any special detection means.

[Means for solving problems]

The present invention provides an optical block that is moved in the radial direction of the disk, and includes an optical head of a first optical system for detecting the skew of a disk mounted on a turntable and an optical head of a second optical system for recording and reproducing the disk. In the optical disc player, the first optical system detects the skew of the disc while the second optical system records and plays the disc, wherein a plurality of discs with different diameters are placed on a turntable. The optical block is configured to be selectively mounted, and after the selective mounting of the disc and before the recording and reproduction, the optical block is moved once in the radial direction of the disc, and the first
The optical system or the second optical system irradiates the disc with light, and the detection element of the first optical system or the second optical system detects the presence or absence of the reflected light to determine the diameter of the disc. It is configured to do so.

[Effect]

According to the above-mentioned technical means, when the first optical system or the second optical system irradiates the disc with light, if there is a disc, the light is reflected and the reflected light is transmitted to the first optical system or the second optical system. It is detected by the detection element of the second optical system. If this is done while moving the optical block in the radial direction of the disk, the diameter of the disk can be accurately determined based on the presence or absence of reflected light depending on the position of the optical block.

Therefore, by using the first or second optical system also as the detection means, it is possible to accurately determine the diameter of the disc selectively mounted on the turntable.

〔Example〕 Embodiments of the present invention will be described below based on the drawings.

First, this optical disk player is configured to be able to selectively use three large, medium, and small disks (hereinafter simply referred to as large, medium, and small disks) 1 and 2.3 with different diameters. has been done.

In Figures 1 and 4, large, medium, and small disks l, 2
．． 3 is selectively mounted horizontally on the turntable 4,
When the turntable 4 is rotationally driven by the drive motor 5, the large, medium, and small disks 1.2.3 are horizontally rotationally driven. An optical block 8 in which a first optical system 6 and a second optical system 7 are provided is arranged below the large, medium, and small disks 1, 2.3. The optical block 8 is driven by a drive motor (not shown) along a horizontally installed guide shaft 9 and a guide rail 10, which are parallel to each other. It is configured to be movable in the directions of arrows a and a'.

Next, in FIG. 4, the first optical system 6 is for detecting the skew of large, medium, and small disks 1, 2.3, and includes a light emitting element 12 consisting of a light emitting diode and a detection element consisting of a solar cell. 13, these light emitting elements 12 and detection elements 13
The lens 14 is arranged above the lens 14. In this example, the radial skew of the large, medium, and small disks I, 2.3 is detected, so the light emitting element 12 and the detection element 13 are used to detect the skew of the large, medium, and small disks I, 2.3
are arranged along a direction perpendicular to the radial direction. Further, the detection element 13 has two detection surfaces 13a.

13b, and these detection surfaces 13a, 13b are large, medium,
They are arranged along the radial direction of the small disks 1, 2.3.

In the first optical system 6 described above, when the light from the light emitting element 12 passes through the lens 14 and is irradiated onto the large, medium, and small disks 1.2.3, the large, medium, and small disks 1, 2. .3 is transmitted through the lens 14 again and is received by the detection element 13. Here, if there is no skew in the large, medium, and small disks 1, 2.3, the reflected light will be reflected by the two detection surfaces 13a of the detection element 13.

The light is received evenly across 13b. And large, medium,
When the small disks 1, 2.3 are skewed, the reflected light is shifted in the radial direction, and therefore more of the reflected light is received by one detection surface 13a or the other detection surface 13b of the detection element 13. It turns out. From the above, due to the difference in the detection output of the reflected light on the two detection surfaces 13a and 13b of the detection element 13, the large, medium, and small disks 1, 2.
skew can be detected.

On the other hand, the second optical system 7 has large, medium, and small disks l.

2.3 for recording and playback. In this second optical system 7, a light emitting element 1 consisting of a laser diode is used.
The light flux emitted from
0 and is irradiated onto the objective lens 22 of the optical head 21. The light beam is then focused by the objective lens 22 and irradiated onto the large, medium, and small disks 1, 2.3 as beam spots. Large, medium and small discs 1. 2.
The light beam reflected and diffracted by lens 3 returns to objective lens 2.
2 to 1/4 wavelength plate 20 and collimator lens 19 in the opposite direction. The reflected light beam is then bent at a right angle by the polarization beam splinter 18, passes through the cylindrical lens 23, and is detected by the detection element 24, which is a detector. In this embodiment, the entire second optical system 7 is provided in the optical block 8, but only the optical head 2 with the objective lens 22 is provided in the optical block 8, and the light emitting element 16 etc. are provided in the fixed part. But it's okay.

In the above-mentioned optical disk player, the large, medium, and small disks 1, 2, and 3 are driven to rotate horizontally.
Radial direction of medium and small disks 1, 2.3 (arrows a and a'
(direction) to move the optical block 8 horizontally. Then, the first optical system 6 detects the skew of the large, medium, and small disks 1, 2, and 3, and aligns the optical axis of the second optical system 7 with respect to the large, medium, and small disks 1, 2, and 3. The large, medium, and small disks 1 and 2 are controlled by the second optical system 7 to be vertical.
The desired recording and reproduction of .degree.3 is performed.

By the way, in the optical disc player of the present invention, the diameters of the large, medium, and small discs 1, 2.3 that are selectively mounted on the turntable 4 are expressed as the large, medium, and small discs l,
2.3, the first optical system 6 or the second optical system 7 is configured so that the discrimination can be made before recording or reproduction.

That is, as shown in FIG.
After either the medium or small disks L2, 3 are selectively mounted, the optical block 8 is attached to the large, medium, small disks 1, 2, .
3 from the inner circumferential side to the outer circumferential side once in the direction of arrow a.

And at this time, the diameter.

Large, medium and small discs D2 and D3 1. 2. Three positions P, each set inside the outermost circumference of 3,
At P, , P, the light emitting element 2 of the first optical system 6 irradiates light onto the large, medium, and small disks 1, 2.3. And big,
The detection element 13 detects the presence or absence of reflected light from the medium and small disks 1 and 2.3, and the large, medium and small disks 1 and 2.3 are detected.
diameter D+, D2. Determine D's.

This discrimination operation will be explained based on FIGS. 1 and 2. First, the optical block 8 is moved to the P3 position, and light is emitted from the light emitting element I2 of the first optical system 6 here.

If the reflected light is not detected by the detection element 13, it is determined that there is no disk at the P3 position (that is, no disk is mounted).

On the other hand, when the reflected light is detected by the detection element 13 at the P3 position, the optical block 8 is further moved in the direction of arrow a to the P2 position. And here again, light emitting element 1
2, if the reflected light is not detected by the detection element 13, it is determined that there is no disk at this P2 position, and the mounted disk is a small disk 3 with a diameter of D3.
It is determined that

Next, when the reflected light is detected by the detection element 13 at the P2 position, the optical block 8 is further moved in the direction of arrow a to the P1 position. If light is emitted by the light emitting element 12 and the reflected light is not detected by the detection element 13, it is determined that there is no disc at this P3 position, and the mounted disc has a diameter and is the middle disc 2. It is determined that something is true. On the other hand, when the reflected light is detected by the detection element 13 at the P1 position, it is determined that the mounted disk is a large disk l having a diameter D1.

Note that once it is determined that there is no disk and the diameter of the disk, the determination operation ends there. In this way, the diameters D+, Dz, and Dy of the disks selectively mounted on the turntable 4 can be determined without rotating the disks, and after this,
The large, medium, and small disks 1, 2, and 3 are rotated to perform desired recording and reproduction.

Note that in the above-described discrimination operation, the position P1. Pz and Pz were set inside the outermost periphery of large, medium, and small disks 1, 2, and 3, respectively;
．． 2. Part L+ where the diameters of 3 do not overlap.

It is sufficient to set it to Lx, Lx. Moreover, the optical block 8 is placed at the positions PI, P! , P'l, the optical block 8 is continuously moved while irradiating light with the light emitting element 12, and the diameter D of the disk is determined depending on the position where the detection of the presence or absence of reflected light by the detection element 13 changes. r, D
It is also possible to determine z, D's.

Furthermore, the optical block 8 is divided into large, medium, and small disks 1 and 2.
．． The diameters DI, Dz, and D:l of the disk may be determined by moving the disk once from the outer circumferential side to the inner circumferential side in the direction of arrow a'. The detection operation in this case is performed as shown in FIG. 3, and the determination is made in the following order: large disk 1, medium disk 2, small disk 3, and no disk installed.

On the other hand, in the same way as the first optical system 6 for skew detection described above determines the diameter of the disc, the second optical system 7 for recording and reproducing irradiates the disc with the light from the light emitting element 16. The presence or absence of the reflected light can also be detected by the detection element 24 to determine whether the disk is large, medium, or small.

Although the embodiments of the present invention have been described above, the structures of the first optical system and the second optical system referred to in the present invention are not limited to those described in the embodiments, and various changes can be made. be. Furthermore, although the embodiment is configured to discriminate between three types of disks: large, medium, and small, four or more types of disks may be used.

〔Effect of the invention〕

As described above, according to the present invention, the diameter of a disc selectively mounted on a turntable can be accurately determined without rotating the disc on the turntable. Therefore, unlike when determining the diameter of a disc based on the time it takes for the disc to reach a predetermined number of revolutions, there is no possibility of a disc slipping on the turntable causing a malfunction in the determination. Even if there are many types of disks with different diameters attached to the system, the diameters of the disks can be determined extremely accurately.

The first optical system and the second optical system are for disc skew detection and disc recording and playback, respectively, and are essential existing devices for this type of optical disc player. This method does not require any new special means for determining this, and there is almost no cost increase.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a schematic sectional view of an optical disc player, FIG. 2 is a flowchart of a discrimination operation, FIG. 3 is a flowchart of another discrimination operation, and FIG. 4 is a flowchart of another discrimination operation. FIG. 3 is a partially cutaway perspective view of the main part. In addition, in the symbols used in the drawings, 1--・--・----1-----Large disk 2.
・・・・−・−１−−−・−・−Medium disk 3−・・−
・−・−・・−Small disk 4・−・−−−−−−−−−−−−−−−−−Turntable 6・−・・−・−・・−・First optical system 7−・−−
m=−・・−・−・−・Second optical system 8−・・・・−・
--------・-Optical block 12, ・---------・
−・−・Light-emitting element 13−−−−−−−−−−−−−・
-・Detection element 16・・・・−・−・−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−1−−−−−−−−−−−−−−−−−−−−−− −−−・−・・−・Detection element.

Claims (1)

[Claims] An optical head of a first optical system for detecting the skew of a disc mounted on a turntable and a second optical system for recording and reproducing the disc is moved in the radial direction of the disc. An optical disc player is provided in an optical block, and the first optical system detects the skew of the disc while the second optical system records and plays the disc. After the selective mounting of the disc and before the recording and reproduction, the optical block is moved once in the radial direction of the disc, and the optical block is configured to be selectively mounted on the first disc.
The optical system or the second optical system irradiates the disc with light, and the detection element of the first optical system or the second optical system detects the presence or absence of the reflected light to determine the diameter of the disc. An optical disc player characterized in that it is configured to.