JPH10143914A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically discriminate plural kinds of optical disks different in track pitch and to start reproduction of a signal for a short time by using an optical disk device which is arranged at a position to which a first reflection diffraction light ray from an optical disk is collected and having a means detecting existence of a first order reflection diffraction light ray of the prescribed range angle for 0 order reflection diffraction light ray. SOLUTION: A detecting section is constituted with a semiconductor laser 1 fixed to a base member 3, an optical lens 4, and a phototdiode 2, an abutting section 3a is provided on the upper part of the member 3. The abutting section 3a is pressed by an optical disk 5, the member 3 is held in a fixed distance for the disk 5. At the time, light emitted from the laser 1 is made a parallel light ray flux 8a by the lens 4, and irradiated vertically of the radius direction of the disk 5. The diode 2 is arraigned at a position at which a reflected first order reflection diffraction light ray flux 8b is collected, and discriminates a kind of the disk 5 by an output of the diode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk device, and more particularly to an optical disk device for recording and reproducing a plurality of types of optical disks having different track pitches, such as a conventional optical disk (for example, CD) and a high-density optical disk (for example, DVD). .

[0002]

2. Description of the Related Art For a conventional optical disc, for example, a CD, a private standard is defined, and according to the standard, a track pitch is 1.6 μm. Further, the standard of the optical video disc is defined in the Japan Electronic Machinery Industry Standard, and according to the standard, the track pitch is 1.6 μm like the CD.

On the other hand, digital video discs or digital versatile discs for recording and reproducing video and audio with digital signals have been developed. DVDs have a higher data recording density than CDs, and have a track pitch of 0.8 to 0.7 μm. In the future, there is a trend that optical disks having a smaller track pitch than conventional CDs and an increased data recording density will be accepted in the market simultaneously with conventional CDs and optical disks.

[0004] When reproducing an optical disk, a procedure corresponding to a different recording signal format is required for each optical disk system. For this reason, when playing back optical disks of different types by the same optical disk device, it is necessary to identify which type of optical disk is to be played back.

Conventionally, the person who operates the optical disk apparatus has previously selected the optical disk system by switching a switch or the like, so that the operation becomes complicated, and if the selection is wrong, there is a problem that the signal reproduction is hindered. there were. The recording signal is reproduced according to a procedure corresponding to a predetermined optical disk system, and the optical disk can be identified by judging whether or not the reproduction is possible. In this case, the signal is reproduced. It takes a long time to start the operation.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an optical disc apparatus for recording and reproducing a plurality of types of optical discs having different track pitches. It is an object of the present invention to provide an optical disk device capable of automatically determining the type and starting reproduction of a signal in a short time.

[0007]

According to the present invention, there is provided an optical disk apparatus comprising: a semiconductor laser; and an irradiating means for irradiating an optical disk with a light beam emitted from the semiconductor laser as a substantially parallel light beam;
A condensing means for condensing a first-order reflected diffracted light beam of a light beam irradiated on the optical disk by the irradiation means; And a primary reflected diffracted light detecting means for detecting the presence or absence of the primary reflected diffracted light having a predetermined range angle with respect to the zero-order reflected diffracted light.

In the above-mentioned optical disk apparatus, the semiconductor laser, the irradiating means, and the primary reflected diffracted light detecting means are integrated.

Further, in the optical disk device, a light beam irradiated by the irradiating means is kept perpendicular to a radial direction of the optical disk by pressing a contact portion provided on the integrated detecting portion against an optical disk surface. It is configured to be lean.

Further, in each of the optical disk devices,
The irradiating means and the condensing means are shared by the same optical element.

Further, in each of the optical disk devices,
At least one of an optical lens and a hologram optical element is used as the irradiating means and the condensing means.

In each of the optical disk devices, the integrated detection unit is provided in any one of a disk transfer unit, a disk storage unit, and an optical pickup support unit.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an integrated detection unit of an optical disk device according to an embodiment of the present invention. The integrated detection unit includes a semiconductor laser 1 fixed to a base member 3, an optical lens 4, and a photodiode 2.
At the upper part of the base member 3, there are provided contact portions 3a, 3a,...

As shown in FIG. 2, the base member 3 of the integrated detection unit is mounted on a disk transfer tray 7 for transferring the disk 5. That is, the base member 3 is fixed to the tip of the leaf spring 6 attached to the spring fixing portion 7a of the disk transfer tray 7 so as to protrude into the hole 7b of the disk transfer tray 7. The contact portions 3a, 3a,.
Is pressed against the optical disk 5 placed on the disk transfer tray 7 by the elastic force of the leaf spring 6.

The disk transfer tray 7 is driven by a drive mechanism (not shown) between a position protruding from the housing of the optical disk device shown in FIGS. 5 and 6 and a position inside the housing.
When the disk transfer tray 7 is at the position shown in FIG.
The optical disk 5 is placed on the disk transfer tray 7 as shown in FIG.
The optical disk 5 is transferred onto a turntable of a reproducing unit (not shown). Thereafter, the reproducing unit is raised, and the turntable lifts the optical disk 5 and clamps the optical disk together with a clamper (not shown) to enter a reproducing state.

FIG. 3 shows a state in which there is no optical disk on the disk transfer tray 7, and FIG. 4 shows a state in which an optical disk is mounted on the disk transfer tray 7. The optical disc 5 pushes down the base member 3 by its own weight, and the contact portions 3a of the base member 3 are brought into pressure contact with the surface of the optical disc 5.

FIG. 2 shows the state shown in FIG. 3 in detail. Since the contact portions 3a, 3a,... Are pressed against the optical disk 5, the base member 3 is maintained at a fixed distance and posture with respect to the optical disk 5. At this time, the light beam emitted from the semiconductor laser 1 is converted by the objective lens 4 into a substantially parallel light beam 8.
Thus, the light is irradiated substantially perpendicularly to the radial direction of the optical disk 5 (CD is shown in FIG. 2).

The semiconductor laser 1 is controlled by control means (not shown) so as to emit light having a substantially constant wavelength. The primary reflected diffracted light beam 8b reflected by the optical disk 5 is collected by the objective lens 4. The photodiode 2 is arranged at a position where the primary reflected diffracted light beam 8b in the case of a CD is collected.

FIGS. 7 and 8 show CD5a and DVD5.
The state of reflection diffraction in each case b is shown. Since pit rows on which signals are recorded are arranged at track pitch intervals on the optical disc, the pit rows can be regarded as a diffraction grating. The track pitch of the CD 5a is about 1.6 μm, and the track pitch of the DVD 5a is about 0.74 μm. Therefore, the pitch P1 of the diffraction grating in the case of CD5a
Is 1.6 μm, and the pitch P2 of the diffraction grating in the case of the DVD 5b is 0.74 μm.

The wavelength of light emitted from the semiconductor laser 1 in this embodiment is about 0.78 μm. Optical lens 4
The parallel light beam 8a applied to the CD 5a is further reflected by the CD 5a to form a primary reflected diffracted light beam 8b and a parallel light beam 8a.
Is defined as θ1 and the wavelength of light emitted from the semiconductor laser 1 is defined as λ, sin ⁻¹ (λ / 1.5) ≦ θ1 ≦ sin ⁻¹ (λ / 1.7). Note that the track pitch tolerance of the CD disk ±
0.1 μm was considered.

Since the parallel light beam 8a is perpendicular to the optical disk surface, the 0th-order reflected light beam is perpendicular to the optical disk and θ1
Is equal to the angle formed by the 0th-order reflected light beam and the 1st-order reflected light beam. The angle formed by the primary reflected diffracted light beam 8c reflected by the DVD 5b and the parallel light beam 8a of the parallel light beam 8a irradiated on the DVD 5b from the optical lens 4 is θ2, and the wavelength of the light irradiated from the semiconductor laser 1 is λ. Then, sin ⁻¹ (λ / 0.71) ≦ θ2 ≦ sin ⁻¹ (λ / 0.77). The tolerance of the track pitch of the DVD disk ± 0.03 μm was taken into consideration.

The photodiode 2 can detect the light obtained by condensing the primary reflected diffracted light beam satisfying the formula by the optical lens 4, and the light obtained by condensing the primary reflected diffracted light beam satisfying the formula by the optical lens 4. Is located at a position where it cannot be detected. The photodiode 2 is connected to a control device of the optical disk device, and can determine whether the optical disk is a CD or a DVD based on an output of the photodiode 2.
The optical disk is discriminated while being transported by the disk transport tray 7, and can be recorded and reproduced immediately after being loaded.

In the above embodiment, the photodiode 2 is disposed at one location as light detecting means for the purpose of discriminating between two types of optical disks having different track pitches.
By arranging a plurality of light detecting means, it is possible to determine the types of many optical disks. For example, when discriminating three types of optical discs having different track pitches, the light detecting means a is arranged at a position for detecting only the primary reflected diffracted light of the type a optical disc, and only the primary reflected diffracted light of the type b optical disc is detected The light detecting means b is arranged at the position to be detected, so that neither the light detecting means a nor the light detecting means b detects the primary reflected diffracted light of the optical disk of type c. In this case, the output of the light detection means a and b
Optical discs having different types of track pitches can be identified.

In the embodiment, the optical lens 4 is used as the irradiation means and the condensing means. However, a hologram optical element can be used instead of the optical lens. Details of the hologram optical element are disclosed in JP-A-8-1111039.

Further, the type of the optical disk can also be determined by attaching the integrated detecting section shown in the embodiment to the supporting member of the optical pickup and bringing the supporting member close to the optical disk. Further, in the case of a disk device with a changer, an integrated detection unit can be provided in the disk storage unit, and the stored disk can be determined at any time.

[0026]

According to the present invention, when a plurality of types of optical disks having different track pitches are recorded and reproduced by the same disk device, the type of the optical disk can be automatically determined, and the disk determining operation before recording and reproduction is performed. Does not take a long time.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing a part of the optical disc device.

FIG. 3 is a sectional view showing a part of the optical disc device.

FIG. 4 is a sectional view showing another state of the portion shown in FIG. 3;

FIG. 5 is an external view showing the optical disc device.

FIG. 6 is an external view showing another state of the optical disc device.

FIG. 7 is an optical path diagram showing the operation of the optical disc device.

FIG. 8 is an optical path diagram showing the operation of the optical disc device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Photodiode 3 Base member, 3a contact part 4 Optical lens 5 Optical disk 6 Plate spring 7 Disk transfer tray, 7a Spring fixing part, 7b hole 8a, 8b, 8c Light beam

Claims (6)

[Claims] 1. A semiconductor laser, an irradiating means for irradiating an optical disk with a light beam emitted from the semiconductor laser as a substantially parallel light beam, and a first-order reflection diffracted light beam of the light beam irradiated on the optical disk by the irradiating means. A light condensing means, and a first-order reflected diffracted light beam from the optical disk, which is arranged at a position where the first-condensed diffracted light beam is condensed by the condensing means; 1 to detect
An optical disc device comprising a next reflected diffracted light detecting means. 2. The optical disc apparatus according to claim 1, further comprising an integrated detection unit in which the semiconductor laser, the irradiation unit, and the first-order reflected diffraction light detection unit are integrated. 3. A structure in which a light beam irradiated by the irradiation means is kept perpendicular to a radial direction of the optical disk by pressing a contact portion provided on the integrated detecting portion against a surface of the optical disk. 3. The optical disk device according to claim 2, wherein: 4. The optical disk device according to claim 1, wherein the irradiating means and the condensing means are shared by the same optical element. 5. The optical disk device according to claim 1, wherein at least one of an optical lens and a hologram optical element is used as said irradiating means and condensing means. 6. The integrated detecting unit includes a disk transfer unit,
6. The optical disk device according to claim 2, wherein the optical disk device is provided in one of a disk storage portion and an optical pickup supporting means.