JPH0359828A - Information processor - Google Patents

Abstract

PURPOSE:To perform processing for recording and reproducing much more quickly by an inexpensive device by providing an optical path separation means for separating and generating a beam for reproducing and a beam for overwriting on the optical path of light emitted from a laser light source. CONSTITUTION:After the light emitted from the laser light source 1 is collimated by a collimating lens 2, it is separated to the beam P for reproducing and the beam Q for overwriting by the optical path separation means 16. Then, the beam P for reproducing is condensed by an objective lens 4 for reproducing and irradiates an optical information recording medium 5. The beam Q for overwriting is condensed by a condensing lens 17 for overwriting and irradiates the optical information recording medium 5, so that the information is reproduced and recorded, and the reflected light is detected by detection means 6 and 18 to perform the focus servo or the tracking servo of the objective lenses 4 and 17. Thus, the processing for recording and reproducing is performed much more quickly and the inexpensive device is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an information processing apparatus that records and reproduces information by irradiating light emitted from a laser light source onto an optical information recording medium such as a magneto-optical disk.

2. Description of the Related Art Conventionally, optical disks, magneto-optical disks, and the like have been commonly used in information processing apparatuses as optical information recording media for recording image information such as documents and graphics at high speed and high density. In particular, magneto-optical disks have large capacity (capable of high-density recording),
Random access, high-speed access, rewriting, etc. were possible, and their development was actively underway.

Conventionally, magneto-optical disks have been used for recording, reproducing, erasing, etc. using a single optical spot, so it took a long time to rewrite information. Therefore, in recent years, attention has been paid to using two light spots to irradiate a magneto-optical disk to record, reproduce, and erase information in order to shorten the rewriting time.

Problems to be Solved by the Invention Specific examples of conventional systems using such two light spots include those disclosed in JP-A-59-217206 and JP-A-60-246034. However, both of these are synthesized using two semiconductor lasers with different wavelengths, and the two light spots formed by this are irradiated onto a magneto-optical disk to record, reproduce, and erase information. . With this method, 2
The method of obtaining one light spot requires the use of two semiconductor lasers. There is also a method in which two information processing devices are built into one drive to obtain two spots.
In this case as well, two semiconductor lasers will be used.

Semiconductor lasers are still expensive components;
It accounts for about 1/2 of the price of the entire device.

Therefore, if two semiconductor lasers are used in one device as in the past, the cost of the entire device increases and production efficiency becomes poor.

Means for Solving the Problems Therefore, in order to solve such problems, the present invention collimates the light emitted from a laser light source using a collimating lens, and then uses this collimated light to record optical information. In an optical pickup device that records, reproduces, and erases information by irradiating the medium with light, an optical path separation means is provided on the optical path of the light emitted from the laser light source to separate and generate a reproduction beam and an overwrite beam. A reproducing objective lens is provided on the optical path of the reproducing beam generated by the optical path separation means, and a reproducing objective lens is provided on the optical path of the light irradiated onto the optical information recording medium and reflected by the reproducing objective lens. A detection means is provided, and an overwrite objective lens is provided on the optical path of the overwrite beam generated by the optical path separation means, and the overwrite objective lens detects the light irradiated onto the optical information recording medium and reflected. Overwriting beam detection means was provided on the optical path.

As a result, the light emitted from the laser light source is collimated by the collimating lens, and then separated into two beams, a reproduction beam and an overwriting beam, by the optical path separation means, and one of the reproduction beams is is focused by a reproduction objective lens and irradiated onto an optical information recording medium, and its reflected light is detected by a reproduction beam detection means, thereby reproducing information and performing focus servo and tracking servo of the reproduction objective lens. The other separated overwriting beam is focused by an overwriting condensing lens and irradiated onto an optical information recording medium to record information, and the reflected light is used for overwriting. By being detected by the beam detection means, focus servo and tracking servo of the overwriting objective lens can be performed. Therefore, by using the optical path separation means in this way, it is possible to generate a beam dedicated to reproduction and a beam dedicated to overwriting with only one laser light source, which allows faster recording and reproduction processing with inexpensive equipment. It is something that can be done.

Example An embodiment of the present invention will be described based on the drawings.

Light (S-polarized wave) emitted from the semiconductor laser 1 is collimated by a collimating lens 2, and then a part of the light is reflected by a non-polarizing beam splitter 3 and the remaining light is transmitted as is. Note that the non-polarizing beam splitter 3 is
If the transmittance is a% and the reflectance is b%, it has a characteristic of a+b#100%.

First, let's look at the light reflected by the non-polarizing beam splitter 3. The reflected light is focused as a reproduction beam P by a reproduction objective lens 4, and becomes a spot of about 1 μm and is irradiated onto the surface of a magneto-optical disk 5 as an optical information recording medium. Further, the reflected light whose plane of polarization has been rotated (Kerr effect) by the magneto-optical disk 5 passes through the reproducing objective lens 4 and the non-polarizing beam splitter 3 in sequence and is guided into the reproducing beam detecting means 6. The light guided to the reproducing beam detection means 6 is focused by a condensing lens 7 and transmitted or reflected by a beam splitter 8. This beam splitter 8 is
Transmittance of P polarized light wave is 100%, transmittance of S polarized light wave is C%,
The reflectance of S polarized light is d%, c+d#100%, c(10
It has the characteristic of 0%. The light that has passed through the beam splitter 8 having such characteristics has its polarization plane rotated by 45° by the λ/2 plate 9 with increased Kerr rotation, and is converted into P-polarized light and S-polarized light by the Wollaston prism 10. The light is separated into waves, and then the cylindrical lens 1
1 (The generatrix direction is 45° with respect to the track of the magneto-optical disk.
The light beam enters the light receiving element 12 in a state where astigmatism occurs due to the tilted light beam, and the magneto-optical signal is reproduced by detecting the difference in light intensity between the two light spots.

Further, the light incident on the light receiving element 12 by the astigmatism method is detected as a focus error signal, and focus control of the reproduction objective lens is performed based on this. On the other hand, the light reflected by the beam splitter 8 is guided to the light receiving element 13, whereby a tracking error signal is detected by the bush-pull method, thereby controlling the tracking of the reproduction objective lens 4.

Next, let us look at the light transmitted through the non-polarizing beam splitter 3. The light transmitted through the non-polarizing beam splitter 3 is guided as an overwriting beam Q to the polarizing beam splitter 4, where all of the light is reflected, passes through the λ/4 plate 15, and becomes circularly polarized light. In this case, the non-polarizing beam splitter 3, the polarizing beam splitter 14, and the quarter-wave plate 5 constitute an optical path separating means 16. The circularly polarized light is then focused by the overwriting objective lens 17 to form a light spot of about 1 μm on the magneto-optical disk 5, thereby recording information. The circularly polarized light reflected by the magneto-optical disk 5 is transmitted to the overwriting objective lens 17.
The circularly polarized light is converted into P-polarized light by the λ/4 plate 15, passes through the polarizing beam splitter 14, and is guided into the overwriting beam detection means 18. In this overwriting beam detection means 18,
Similar to the reproduction beam detection means 6 described above, the light receiving element 1
2.13 is used to perform focus control and tracking control of the overwriting objective lens 17.

As mentioned above, during reproduction, the reproduction beam (■) formed in a spot by the reproduction objective lens 4 is used.
During recording, the overwriting beam Q formed into a spot by the overwriting objective lens 17 is used to perform magnetic field modulation using the magnetic head 19 disposed facing the magneto-optical disk 11, thereby performing recording.

Finally, a specific example will be given and explained.

When the power of the spot of the reproducing beam P on the magneto-optical disk 5 surface is P'r = 2 mW, and the power of the spot of the overwriting beam Q on the magneto-optical disk 5 surface is Po = 10 mW, an unpolarized beam splitter 3
It is sufficient to set the transmittance a=80% and the reflectance b=20%, that is, the transmittance Pr of the non-polarizing beam splitter 3
, reflectance P.

For, a= (Pr/Po)X100%, b=100
-a%, the reproduction beam P and the overwriting beam Q can be obtained satisfactorily.゛Effects of Investigation According to the present invention, by providing an optical path separation means on the optical path of the light emitted from the laser light source, it is possible to generate a beam exclusively for reproduction and a beam exclusively for overwriting with only one laser light source. This makes it possible to process recording and reproduction much more quickly, and since it is not necessary to use two laser light sources as in the conventional method, an inexpensive device can be obtained.

[Brief explanation of drawings]

The drawing is a configuration diagram showing an embodiment of the present invention. 1... Laser light source, 2... Collimating lens, 4...
... Reproduction objective lens, 5... Optical information recording medium, 6.
... Reproduction beam detection means, 16... Optical path separation means,
17... Objective lens for overwriting, 18... Beam detection means for overwriting, ... Beam for reproduction, Q... Beam for overriding Applicant Rico Co., Ltd.

Claims (1)

[Claims] In an optical pickup device that records, reproduces, and erases information by collimating light emitted from a laser light source using a collimating lens and then irradiating the collimated light onto an optical information recording medium, An optical path separation means for separating and generating a reproduction beam and an overwriting beam is provided on the optical path of the emitted light, and a reproduction objective lens is provided on the optical path of the reproduction beam generated by the optical path separation means, A reproducing beam detection means is provided on the optical path of the light irradiated and reflected by the optical information recording medium by the reproducing objective lens, and a reproducing beam detecting means is provided on the optical path of the overwriting beam generated by the optical path separating means for overwriting. An information processing apparatus comprising: an objective lens; and an overwrite beam detection means on an optical path of light irradiated onto the optical information recording medium and reflected by the overwrite objective lens.