JPH0547027A - Optical recording/reproducing device - Google Patents

Abstract

PURPOSE:To shorten the time required for recording/reproducing. CONSTITUTION:The recording laser beam emitted from a laser diode 1 is made incident on an objective lens 6 through a collimator lens 2 and beam splitters 3 and 5, and is converged at diffraction limit on an optical disk 7. The reproducing laser beam emitted from a laser diode 11 is made incident on the objective lens 6 in the state of divergence, and the optical disk 7 is irradiated not so as to reach a diffraction limit. The reproducing laser beam reflected on the optical disk 7 is made incident on a photodetector 14 which is two-dimensionally arranged through the objective lens 6, the beam splitters 5 and 3 and a convex lens 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for optically recording / reproducing information.

[0002]

2. Description of the Related Art In a conventional optical disc, for example, laser light is focused to the diffraction limit to record data as a pit train on the optical disc. Then, at the time of reproduction, the level of the laser beam is made sufficiently smaller than that at the time of recording so as not to give an optical change to the optical disc, and the disc is irradiated with the diffraction limit as well. Then, the light reflected by the disk is received by a photodiode or the like, photoelectrically converted, and the recorded signal is reproduced.

[0003]

As described above, in the conventional apparatus, since recording and reproducing are performed one track at a time, there is a problem that it takes a long time to record data and reproduce it. It was

The present invention has been made in view of such a situation, and makes it possible to shorten the time taken to record data and reproduce it.

[0005]

SUMMARY OF THE INVENTION An optical recording / reproducing apparatus of the present invention comprises an objective lens for converging recording light to a diffraction limit on the disc, and an reproducing lens on the disc so that the reproducing light does not reach the diffraction limit. It is characterized in that it is provided with an optical system for irradiating and a photodetector arranged two-dimensionally for receiving the light for reproduction having passed through the disc.

[0006]

In the optical recording / reproducing apparatus having the above construction, the recording is performed by the recording light converged to the diffraction limit, and the reproduction is performed by the reproducing light not reaching the diffraction limit. Therefore, recording is sequentially performed one track at a time, but reproduction can be performed simultaneously on a plurality of tracks. As a result, the time required for recording and reproducing can be shortened.

[0007]

1 is a diagram showing the configuration of an embodiment of an optical recording / reproducing apparatus of the present invention. The laser diode 1 generates laser light for recording. The collimator lens 2 collimates the recording laser light emitted from the laser diode 1.
The beam splitter 3 separates the reproducing laser light reflected by the optical disk 7 from the recording laser light emitted from the laser diode 1 toward the optical disk 7.
Further, the beam splitter 5 separates the reproduction light incident on the optical disk 7 from the reproduction laser light reflected by the optical disk 7. The objective lens 6 focuses the laser light for recording or reproduction on the optical disk 7.

The laser diode 11 generates a reproduction laser beam. This laser diode 11 has a convex lens 12
It is located at a position shorter than the focal length of. Therefore, the reproducing laser light emitted from the convex lens 12 is divergent light. The convex lens 13 focuses the reproduction laser light reflected by the optical disk 7 on the photodetector 14.

Next, the operation will be described. In the recording mode, the laser light emitted from the laser diode 1 is collimated by the collimator lens 2 and becomes parallel light, which is incident on the objective lens 6 via the beam splitters 3 and 5. The objective lens 6 focuses the recording laser light to the diffraction limit and irradiates the optical disk 7. As a result, an optical change is given to the optical disc 7, and data is recorded on the optical disc 7 as pits. The optical disk 7 is rotated by a motor (not shown), and data is sequentially recorded for each track.

Next, in the reproducing mode, the optical disk 7 is irradiated with the laser light emitted from the laser diode 11 instead of the laser diode 1. That is, the laser light emitted from the laser diode 11 is incident on the beam splitter 5 via the convex lens 12. The reproducing laser light reflected by the reflecting surface 5a of the beam splitter 5 is incident on the convex lens 6 in a divergent state. As a result, the reproduction laser light focused by the convex lens 6 does not reach the diffraction limit and illuminates a wide range of the optical disk 7. FIG. 2 schematically shows this state. That is, a plurality of pits of a plurality of tracks are located in the range irradiated with the reproducing laser beam.

The reproducing laser light reflected by the optical disk 7 passes through the objective lens 6 and the beam splitter 5 and is incident on the beam splitter 3. The reproducing laser light reflected by the reflecting surface 3 a of the beam splitter 3 is convex lens 13
And is focused on the photodetector 14. Photo detector 1
4, for example, has a configuration in which a plurality of photodiodes, for example, are arranged two-dimensionally (that is, in a plane) as shown in FIG. An image corresponding to the pit of each track shown in FIG. 2 is formed on each photodiode. Therefore, it is possible to simultaneously reproduce a plurality of tracks on the optical disk 7 from the outputs of the photodiodes of the photodetector 14.

The laser diode 1 for recording, the laser diode 11 for reproducing, and other optical systems for guiding the laser light for recording and the laser light for reproducing are arranged inside one optical recording / reproducing apparatus. .. Therefore, in one optical recording / reproducing apparatus, when data is recorded and the recorded data is immediately reproduced, the time from the start of recording to the completion of reproduction can be shortened.

FIG. 4 shows the configuration of the second embodiment of the optical recording / reproducing apparatus of the present invention. In this embodiment, the optical disk is a transmissive optical disk 21. In this case, the laser diode 11 for generating the reproducing laser light and the convex lens 12 for irradiating the reproducing laser light from the optical disk 21 are arranged on the side opposite to the recording system of the optical disk 21. That is, in the embodiment of FIG. 4, the objective lens 6 is arranged above the optical disc 21, while the laser diode 11 and the convex lens 12 are arranged below the optical disc 21.

Data recording is performed in the same manner as in the embodiment shown in FIG. On the other hand, in reproducing, the reproducing laser light emitted from the laser diode 11 is applied to the optical disk 21 from the lower side by the convex lens 12. In this case, as in the case of the embodiment of FIG. 1, the convex lens 1
The area irradiated by 2 does not reach the diffraction limit. Then, the light transmitted through the optical disk 21 is irradiated onto the photodetector 14 via the objective lens 6, the beam splitter 3 (the beam splitter 5 in the embodiment of FIG. 1 is not necessary), and the convex lens 13.

FIG. 5 shows a third embodiment of the optical recording / reproducing apparatus of the present invention. In this embodiment, the optical disc 31 is configured to emit light by itself. That is,
In this embodiment, the optical disc 31 has a function as a light source for generating reproduction light and a function as an optical system for irradiating reproduction light over a wide range so as not to reach the diffraction limit. There is. The reproduction light emitted from the optical disc 31 is reproduced by the objective lens 6, the beam splitter 3,
The light is incident on the photodetector 14 via the convex lens 13. The operation at the time of recording is similar to that in the embodiment of FIG.

In addition, a surface emitting laser diode or LED can be used as a reproducing light source.

[0017]

As described above, according to the optical recording / reproducing apparatus of the present invention, the recording is performed by the light focused on the diffraction limit, and the reproduction is performed by the light not reaching the diffraction limit.
At the time of reproduction, it becomes possible to reproduce a plurality of tracks at the same time, and the time from recording to reproduction can be shortened. Further, the shuffling range of the recording data can be widened.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of an embodiment of an optical recording / reproducing apparatus of the present invention.

FIG. 2 is a diagram illustrating a state of a reproduction laser beam on an optical disc.

FIG. 3 is a front view showing the configuration of a photodetector 14 in the embodiment of FIG.

FIG. 4 is a side view showing the configuration of the second embodiment of the optical recording / reproducing apparatus of the present invention.

FIG. 5 is a side view showing the configuration of the third embodiment of the optical recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 1 Laser Diode 2 Collimator Lens 3, 5 Beam Splitter 6 Convex Lens 7 Optical Disc 11 Laser Diode 12, 13 Convex Lens 14 Photodetector 21, 31 Optical Disc

Claims (1)

[Claims] 1. A recording light source for generating recording light, an objective lens for focusing the recording light on a disc to a diffraction limit, a reproducing light source for generating reproducing light, and the reproducing light source. Optical system for irradiating the disc with the above-mentioned light so that it does not reach the diffraction limit, and a two-dimensionally arranged photodetector for receiving the reproduction light passing through the disc. Recording / playback device.