JPH02244445A - Optical information recording medium and optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide the recording medium which has functions of both a ROM and a RAM and can improve the recording density of information signals and the transfer speed of reproduction signals by forming a magnetic recording film to a uniform film thickness and forming a coating layer consisting of the same medium as the medium of a substrate on which phase pits are formed or the medium having approximately the same refractive index as the refractive index thereof on the magnetic recording film. CONSTITUTION:An optical disk 20 is provided with the coating layer 23 consisting of the same material as the material of the substrate 21a or the material having the same refractive angle as the refractive angle of the substrate and the magnetic recording film 22 which is sandwiched by the substrate 21a and the coating layer 23 and has a uniform thickness. Both surfaces of this optical disk 20, i.e. one surface of the substrate 21a and one surface of the coating layer 23 are flat and the optical disk 20 is molded to the approximately uniform thickness exclusive of the non-information recording part of the peripheral edge part and central part. The simultaneous and independent reproduction of the information signals by the phase pits and the information signals recorded on the magnetic recording film is executed by single light beam in this way and the ROM and RAM coexisting optical disk which is doubled in the recording density of the information signals and the transfer speed of the reproduction signals is thus obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording medium and an optical information recording/reproducing device for optically recording and reproducing information, and in particular to an optical information recording/reproducing device capable of recording high-density information signals. The present invention relates to an optical information recording medium and an optical information recording/reproducing apparatus for recording and reproducing information signals on the recording medium at high speed.

[Conventional technology]

Conventionally known optical information recording media (hereinafter referred to as "optical information recording media")

There are two types of optical discs, such as CDs (compact discs), in which information signals are recorded in advance using uneven phase bits, and magneto-optical discs, in which signals can be recorded freely by the user. There are two types: those that can erase already recorded signals, and those that can erase already recorded signals.

The former has the advantage of being able to produce optical discs on which a large amount of information is recorded at relatively low cost, but is limited to use as ROM (read-on memory). On the other hand, as the demand for optical disks increases, there is an increasing demand for a ROM/RAM mixed optical disk that has a ROM function as well as a so-called RAM (random access memory) function that allows new signals to be added and rewritten.

As a method to meet such demands, Japanese Patent Laid-Open No. 61-6
As shown in Japanese Patent No. 8742 and Japanese Patent Application Laid-open No. 61-271627, a system has been proposed in which recording tracks provided with phase bits and recording tracks of magneto-optical signals are arranged alternately.

According to this method, the above-mentioned ROM and RAM mixed optical disk can be realized, and since the signal detection principle of phase bits and the detection principle of magneto-optical signals are completely different, crosstalk between image recording tracks can be significantly reduced. . As a result, the distance between the phase bit recording track and the magneto-optical recording track can be narrowed compared to conventional optical disks, and the signal recording density of the optical disk can be increased compared to conventional optical disks.

[Problem to be solved by the invention]

However, in the above-mentioned method, when the recording track spacing becomes about half of the conventional one, the signal amplitude of the magneto-optical signal may be modulated due to the influence of crosstalk of phase bits. There still remains a problem in increasing the amount by about twice as much.

Furthermore, in this method, since the signal is reproduced for each recording track as before, there is a problem in that the transfer speed of the reproduced signal remains the same as before.

An object of the present invention is to provide an optical disc that has both ROM and RAM functions and can approximately double both the recording density of information signals and the transfer speed of reproduced signals, and an information recording and reproducing device thereof. be.

[Means for Solving 111M] In order to solve the above-mentioned problems and achieve the object, the optical disk of the present invention has a magnetic recording film for recording a magneto-optical signal at least on a track on which a phase bit is formed. The magnetic recording film is formed to have a uniform thickness, and is further coated on the magnetic recording film with the same medium as the substrate on which the phase bit is formed, for example, PMMA (polymethyl methacrylate) or a medium with substantially the same refractive index. The first feature is that a layer is formed, and a wavelength-selective film or a polarization-selective film is provided between the substrate and the magnetic recording film, or between the magnetic recording film and the coating layer. The second feature is that the film is provided with a uniform thickness.

Further, the optical information recording and reproducing apparatus of the present invention detects a change in light intensity due to diffraction of phase bits from the laser beam reflected by the optical disk, and reproduces an information signal recorded in phase bits based on the detection result. The rotation of the polarization plane due to the magneto-optical effect (Faraday effect) of the laser beam transmitted through the optical head and the optical disk is detected.
The optical disc is also equipped with a magneto-optical signal detecting head for reproducing the magneto-optical signal recorded on the optical disc, and at least two or more semiconductor laser elements and the light beams emitted from each of the semiconductor laser elements can be separately recorded on the optical disc. the optical head detects a change in the intensity of reflected light of one of the light beams irradiated onto the optical disk, and the magneto-optical signal detection head detects a change in the intensity of reflected light of one of the light beams irradiated onto the optical disk; The third and fourth features are that the device is configured to detect the rotation of the plane of polarization due to the magneto-optical effect of the transmitted light of one of the other light beams.

Further, the optical information recording/reproducing apparatus of the present invention includes at least two semiconductor laser elements that generate light beams of different wavelengths, and a common laser diode for separately irradiating the optical disc with the light beams emitted from each semiconductor element. A fifth feature lies in that the optical system includes an optical system and one of a wavelength-selective filter and a wavelength-selective mirror included in the optical system.6 [Function] The present invention having the first feature Since different information signals can be recorded on the same track as phase bits or magneto-optical signals, the information recording density can be improved.

Further, in the present invention having the third and fourth features,
It is possible to reproduce the information signal of the optical disk recorded using phase bits and the reproduction of the magneto-optical signal in real time. Furthermore, by adding a known magnetic head for recording magneto-optical signals to the present invention having the third and third features, it is possible to reproduce the information signal recorded in phase bits and record the magneto-optical signal in real time. can.

According to the present invention further having second and fifth features,
The configurations of the optical head for recording, reproducing, and simultaneously reproducing different information signals and the magneto-optical signal detection head can be simplified.

(Example〕 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a cross-sectional perspective view showing essential parts of an optical disc according to an embodiment of the present invention, FIG. 3(a) is a cross-sectional view taken along line 8-A' in FIG. Figure 3 is a characteristic diagram of the reflected light intensity of the light beam between phase bits and on phase pits, respectively.
d) is a diagram showing the relationship between the polarization directions of the incident light beam and the light transmitted through the optical disk.

The optical disc 20 shown in FIGS. 2 and 3(a) is
A substrate 21a, a covering layer 23 made of the same material as the substrate 21a or a material having the same refraction angle, and these substrates 2
1a and a magnetic recording film 22 of uniform thickness sandwiched between a coating layer 23.

It has a so-called sand inch structure. Both surfaces of the optical disk 20, that is, one surface of the substrate 21a and one surface of the coating layer 23, are flat, and the thickness of the optical disk 20 is substantially uniform except for at least the peripheral portion and the non-information recording portion at the center. It is molded into.

In the optical disc 20 having the above configuration, a concave-convex phase bit 21 is simultaneously formed on the substrate 21a by injection molding at the time of molding the optical disc 20 in accordance with the first information signal. Furthermore, a magnetic domain 24 is formed in the magnetic recording film 22 on the same track as the track in which the phase bit 21 is formed in accordance with the second information signal.

The magnetic domains 24 are formed by irradiating the magnetic recording film 22 with a light beam while applying a magnetic field to the optical disk 20.
Performed by reversing the magnetization direction of the recording film, that is, presence or absence of reversal of magnetization direction (presence or absence of magnetic domain)
This records the level of the information signal.

The information signals recorded in the phase pits 21 and the information signals recorded in the magnetized domains 24 on the optical disk 20 are reproduced according to the following principle.

In FIG. 3(a), a laser beam 50 incident from one side (lower side of the figure) of the optical disk 20 is partially reflected at the boundary between the phase bit 21 in the optical disk 20 and the magnetic recording film 22, and becomes a light beam. (Reflected light) 51, and the rest passes through the optical disk 20 and becomes a light beam (Transmitted light) 52. One reflected light 51 is diffracted by the unevenness of the phase bit 21, and the light intensity is modulated. If the reflected light is from a phase bit, the reflected light intensity will be as shown in FIG. 3(c).

If the reflected light is between phase pits, the reflected light intensity will be as shown in FIG. 3(b). Therefore, the information signal can be reproduced based on this difference in reflected light intensity.

On the other hand, when the transmitted light 52 passes through the magnetic recording film 22, due to the magneto-optical effect (Faraday effect), the information signal recorded on the magnetic recording film 22, that is, the third The plane of polarization rotates as shown in Figure (d).

Incidentally, the unevenness of the magnetic recording film 22 formed along the phase bits 21 is filled with the coating layer 23, so that the surface is almost flat. Therefore, for the transmitted light 52, the optical thickness of the optical disc is almost uniform regardless of the location.
No intensity modulation occurs due to diffraction of phase bits.

Therefore, for the reflected light 51, a light detection system similar to that of the conventional optical head for reproducing phase pit discs is provided, and for the transmitted light 52, the rotation of the polarization plane is converted into a change in intensity and detected. By providing a head for detecting a magneto-optical signal, a single light beam 50 can detect an information signal based on reflected light 51 by the phase bit 21 and an information signal recorded on the magnetic recording film 22 based on transmitted light 52. can be played simultaneously and independently. Moreover, this optical disk can completely independently overwrite any information signal as a magneto-optical signal on the same track as the recording track of the phase bit 21, so the information signal can be doubled compared to the conventional optical disk. disk can be realized.

Next, an embodiment of an optical information recording and reproducing apparatus for reading and writing information to and from the optical disc of the present invention and other embodiments of the optical disc will be described in detail with reference to the drawings.

FIG. 1 is a front view showing a first embodiment of the optical information recording/reproducing apparatus of the present invention.

In FIG. 1, a laser beam 50 emitted from a semiconductor laser device 1 is reflected by a half mirror 2, and then focused by an objective lens 3 onto an optical disk 2o to form a light spot 10.
form.

The laser beam 5o incident on the optical disc 20 is as follows.

Part of the light is reflected at the interface between the phase bit 21 (substrate 21a) and the magnetic recording film 22 and between the magnetic recording film 22 and the coating layer 23, and becomes a reflected light beam 51.

Then, this reflected light beam 51 passes through the objective lens 3 again in the opposite direction, passes through the half mirror 2 and the concave lens 4, and reaches the photodetector 5. As described above with reference to FIG. 3, this reflected light beam 51 is modulated in light intensity by the diffraction phenomenon caused by the phase bit 21, so that the output signal of the photodetector 115 is Based on the phase pit signal reproducing circuit 201, the information signal A is
can be played. At the same time, each control signal for focusing and tracking for accurately irradiating the optical spot 10 onto the recording track of the optical disk 20 is also transmitted to the optical spot control signal detection circuit 20 from the output signal of the photodetector 5.
Detected by 2.

This control signal is input to the actuator drive circuit 203, and the output of the actuator drive circuit 203 drives the actuator 204, thereby controlling the position of the objective lens 3. Note that each of the circuits 201, 202,
203 and the detection method of each control signal may be the same circuit and detection method as in the conventional read-only optical disk system, and the description thereof will be omitted since it is not directly related to the main point of the present invention.

Note that the reflected light beam 51 reflected at the boundary between the magnetic recording film 22 and the coating layer 23 is reflected by the magnetic recording film 22 and the coating layer 23.
When it is reflected at the boundary surface of By making the light non-polarizing, the information signal B will not leak into the output signal of the photodetector 5 because it will not be converted into light intensity.

On the other hand, a part of the incident light flux 50 passes through the coating layer 23 of the magnetic recording 1I22 and enters the magneto-optical signal detection head 100. Since the phase pits 21 of the optical disk 2o are embedded in the coating layer 23 having the same refractive index as the substrate 21a of the phase bit 21, this transmitted light beam 52 is not subjected to light intensity modulation due to the diffraction of the first phase pit 21. Instead, a rotation of the plane of polarization (rotation angle ±θF) occurs in response to the information signal B due to the magneto-optical effect (Faraday effect) caused by the magnetized domains 24 of the magnetic recording film 22.

θ2 indicates a Faraday rotation angle. The magneto-optical signal detection head 100 converts the rotation of the polarization plane of the optical disk transmitted light beam 52 into light intensity, and furthermore, the magneto-optical signal detection head 100 includes Optical signal detection head 100
The output signal is input to the magneto-optical signal reproducing circuit 205, and the information signal B recorded on the magnetic recording film 22 can be detected by the magneto-optical signal reproducing circuit 205. Note that this magneto-optical signal reproducing circuit 205 may be a circuit similar to a magneto-optical signal reproducing circuit used in a conventional magneto-optical disk system, so a description thereof will be omitted.

FIG. 4, FIG. 5, and FIG. 6 are diagrams each showing a specific example of the magneto-optical signal detection head 100.

The magneto-optical signal detection head 100 shown in 4th wJ is similar to the conventional head detection optical system for a magneto-optical disk, including a condenser lens 101, a half-wave plate 102, an analyzer 103, and photodetectors 104a and 104b. , a differential amplifier 108, etc., the head is based on a differential detection method that detects the light intensity of two mutually perpendicular predetermined polarized components of the transmitted light beam 52 and outputs a magneto-optical signal from the difference signal. .

On the other hand, the magneto-optical signal detection head 100 shown in FIG. A polarizing plate 105 whose transmittance changes depending on the polarization direction of the incident light is placed on the surface of the polarizer 107 so that the polarization direction (transmission axis) at which the maximum transmittance occurs is one of the polarization directions of the Faraday-rotated transmitted light beam 52. On the other hand, place it so that it is almost perpendicular. The relationship between the polarization direction of the light transmitted through the disk 20 and the transmission axis of the polarizing plate 105 is as shown in FIG. 5(b).

The magneto-optical signal detecting head 100 having such a configuration is arranged to face the optical disc 20 so that the transmitted light beam 52 of the optical disc 20 is incident thereon, and the summation of the output signals of each photodetector 107 is taken by the adding circuit 109. Therefore, a magneto-optical signal can be detected by a direct method in which a change in the rotation angle of the polarization plane of a transmitted light beam is directly converted into an electric signal and detected. The characteristics of this head 100 are, firstly, that the number of parts is extremely small, and secondly, the magneto-optical signal detecting head 100 is moved in the radial direction of the optical disk 20 in accordance with the access operation of the irradiation optical system for the optical spot 10. There is no need to move the optical disc 2.
Since it is only necessary to fix the access mechanism facing 0, the access mechanism system of the recording/reproducing apparatus is simplified.

Furthermore, in the magneto-optical signal detection head 100 of FIG. 6(a), two rows of photodetector arrays 107 are arranged, and the transmission axes are substantially perpendicular to each other on the surface of the photodetector arrays 107 arranged in each row. Two types of polarizing plates 105 and 106 are provided. A detection signal 110a obtained by the photodetector array 107 in each column.

By subtracting 110b by the differential amplifier 108, it is possible to detect a magneto-optical signal using a differential method similar to a conventional magneto-optical disk system.

FIG. 6(b) is a diagram showing the positional relationship between the transmission axes of the polarizing plates 105 and 106 and the polarization direction of transmitted light. Detection of magneto-optical signals using such a differential method has the advantage that the S/N (signal-to-noise ratio) of the magneto-optical signals is better than the detection method using a direct method as shown in the embodiment shown in FIG. There is.

By using the optical information recording/reproducing device configured as described above, the information signal A based on the phase bit 21 in the optical disk 20 and the information signal B recorded on the magnetic recording film 22 can be simultaneously and completely independently transmitted. can be played. Therefore, the transfer speed of reproduced signals is twice as high as that of conventional optical disk systems.

Further, the information signal B recorded on the magnetic recording film 22 is as follows.

As with conventional magneto-optical disk systems, by modulating the optical intensity of the incident laser beam 50 under a predetermined magnetic field,
This is a signal that can be freely recorded and erased by the user. Moreover, since this magneto-optical signal can be overwritten on the recording track of the phase pit 21, the recording density of the information signal is substantially doubled compared to the conventional optical disk system.

Note that when recording the information signal B on the magnetic recording film 22, a predetermined magnetic field is required as described above, and the magnetic head for generating this magnetic field is the magneto-optical signal detection head 1.
00 or around the actuator 204. Furthermore, by modulating the magnetic field generated by this magnetic head, the information signal B can be recorded on the magnetic recording film 22 while keeping the intensity of the incident laser beam 50 constant. When such a magnetic field modulation method is used, the information signal A recorded in the phase bit 21 is reproduced by the incident laser beam 50 irradiated with a constant light intensity, and at the same time the information signal B is transmitted to the magnetic recording film 22. It is also possible to record the

Incidentally, since a known magnetic head may be used as the magnetic head, a description of its configuration and arrangement will be omitted.

FIG. 7 is a front view showing a second embodiment of the present invention. In the figure, the symbols with alphabetical auxiliary symbols indicate the same or equivalent parts as the same symbols in FIG. Separately from the beam generating device, there is an optical beam generating device [!
3°01 was provided separately. For example, the optical head 300 is
The optical head may have a configuration similar to that of an optical head for reproducing phase bit discs, typified by an optical head used in a conventional read-only optical disc system that uses a 3-beam system as a tracking detection method using a diffraction grating 6. Beam generator 1
301 uses a device similar to the optical information recording/reproducing device shown in FIG. 1, for example. A light spot 10a is irradiated onto the optical disc 20 from the reflected light of the optical disc 20,
10b focus and tracking control signals are detected,
By using these two optical heads that control the position of the optical spot by controlling the actuators 204a and 204b, it is possible to freely reproduce the magneto-optical signal using the optical intensity modulation method while reproducing the phase bit signal. Can be recorded or erased.

FIG. 8 is a front view showing a third embodiment of the present invention.

In this figure, the same reference numerals as those in FIG. The optical spot 10b and the optical disc 20
It irradiates the area. In FIG. 8, optical disk 2
Light spots 10a, 10b and phase pit 2 on 0
1 and the magnetized domain 24 are shown in an enlarged plan view of the optical disk.

In this third embodiment, two
Semiconductor laser elements 1a and lb are provided. After the laser beam of wavelength λ emitted by the semiconductor laser element 1a is reflected by the half mirror 2, the transmittance is high for the light of wavelength λ1, and the laser beam of wavelength λ2 emitted by the semiconductor laser element 1b is reflected.
The light passes through the wavelength-selective mirror 7 which has a high reflectance, and is transferred to the optical disc 2 by the objective lens 3.
0 is irradiated with a light spot log. On the other hand, the laser beam of wavelength λ8 emitted from the semiconductor laser element 1b is reflected by the wavelength selective mirror 7, and then passes through almost the same optical path as the beam from the semiconductor laser element 1a, and is formed into a light spot loa by the objective lens 3. A light spot 10b is irradiated at the same position or in the vicinity thereof.

A light spot 10a reflected by the optical disc 20.

The reflected light beam 10b passes through the objective lens 3 again from the opposite side and reaches the wavelength-selective mirror 7, and only the light beam from the optical sbot 10a, that is, the light beam with wavelength λ1, passes through the wavelength-selective mirror 7 and forms a half mirror. 2. The light passes through the objective lens 4 and enters the photodetector 5.

Similar to the first embodiment, an information signal (information signal A) based on one phase bit, a focus of a light spot, and a tracking control signal are detected. On the other hand, the light beams of wavelengths λ and λ transmitted through the optical disk 20 are transmitted to the magneto-optical signal detection head 100.
′.

The magneto-optical signal detection head 1001 is, for example, shown in FIG. 9(a).
), the detection head 1 shown in FIGS. 5 and 6
00 polarizing plate 105 (lower side in FIG. 9).
The transmittance is approximately 0% for light of wavelength λ, and approximately 100% for light of wavelength λ. Figure 9(b)
A wavelength selective filter 12 having characteristics as shown in
It is formed by pasting 0 together. Only the light beam from the light spot 10b, that is, the light beam with wavelength λ8 is filtered 120. The light passes through the polarizing plate 105 and reaches the photodetector array.

By using such a magneto-optical signal detection head,
If only one optical spot irradiation system is included, the recording, erasing, and reproducing of the magneto-optical signal (information signal B) can be performed simultaneously and completely independently.

FIG. 10 is a front view showing a fourth embodiment of the present invention. The same reference numerals as in FIG. 1 indicate the same or equivalent parts. This fourth embodiment replaces the two semiconductor laser elements of the third embodiment with two laser emitting elements that have different wavelengths and can be independently modulated. This is an example in which the number of parts is reduced by replacing the semiconductor array 1' with a semiconductor array 1' provided in a separate package.

In this example, a wavelength-selective mirror 7 is placed in front of the photodetector 5, and out of the reflected light from the optical disk 20, only a light beam with a wavelength λ1 passes through the wavelength-selective mirror 7 and is detected by the photodetector 5. I am trying to make it input to .

FIG. 11 is a front view showing a fifth embodiment of the present invention.

In this fifth embodiment, a device using a semiconductor laser array 1' similar to that of the fourth embodiment is used, and the head 100' of the third embodiment is replaced with the head 100' of the third embodiment as a head for detecting a magneto-optical signal. This is an example in which a head that does not use a wavelength separation filter like the magneto-optical signal detection head 100 shown in FIG. 6 is provided. When using a recording/reproducing apparatus with such a configuration, as shown in FIG. For example, between Fig. 12 (b
), that is, the wavelength selective film 24 is uniformly coated so that the transmittance is almost 0% for light with wavelength λ, and the transmittance is almost 100% for light with wavelength λ2. An optical disc 20' provided with a film thickness is used. When such an optical disc 20' is used, the light beam reflected by the optical disc 20' and reaching the photodetector 5 is only the light beam with wavelength λ1,
In addition, since the light beam that passes through the optical disk 20'' and reaches the magneto-optical signal detection head 100 is only the light beam of wavelength λ2, the recording/reproducing device side has a light beam for reproducing the phase bit signal and a light beam for recording, erasing, and reproducing the magneto-optical signal. There is no need to provide an optical means such as the wavelength selective mirror 7 for separating the light beams.

In the fifth embodiment, the wavelength selective IllI 24 is provided in the optical disk 20', but a polarizing film whose transmittance varies depending on the polarization direction of the incident light is provided between the phase bit 21 and the magnetic recording 1124. Similar luminous flux separation can also be performed. In this case, a semiconductor laser array including two laser light emitting elements that emit laser beams whose polarization directions are substantially perpendicular to each other is used as the semiconductor laser element of the recording/reproducing apparatus. Using such a semiconductor laser element, the wavelengths of the laser beams emitted from each laser emitting element of this semiconductor laser array may be approximately equal, so there is no need to use a wide wavelength range chromatic aberration correction lens as the objective lens. The manufacturing cost of objective lenses can be reduced.

Note that the transmission axis of the polarizing film provided in the optical disc 20' is, for example, the direction of the transmission axis with respect to the radial direction of the optical disc (polarization direction where the transmittance is maximum) as shown in FIG.
The inclination of the optical disc 20' is provided so that it is approximately constant regardless of the location within the optical disc 20'.

It is also formed on the optical disk 20'. The semiconductor laser element is arranged so that the polarization direction of one of the two light spots is parallel to the transmission axis direction of the polarizing film, and the polarization direction of the other light spot is perpendicular.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, any information signal can be overwritten as a magneto-optical signal on an optical disk in which a phase bit is provided in accordance with a predetermined information signal.
A ROM that doubles both the recording density of information signals and the transfer speed of reproduced signals because it is possible to simultaneously and independently reproduce information signals based on phase bits and information signals recorded on a magnetic recording film with a single light beam. , a RAM-mixed optical disk can be realized.

[Brief explanation of drawings]

FIG. 1 is a front view of an optical information recording/reproducing apparatus showing an embodiment of the present invention, FIGS. 2 and 3 are perspective views and sectional views showing the structure of an optical information recording medium of the present invention, and FIG. The figure is a front view showing an example of a magneto-optical signal detecting head included in the optical information recording/reproducing apparatus of the present invention, and FIGS. 5 and 6 are perspective views showing other examples of the magneto-optical signal detecting head. Figures 7 and 8
10 and 11 are perspective views showing examples of magneto-optical signal reproducing heads used in the embodiments of optical information recording of the present invention shown in FIGS. 8 and 10, and FIGS. 12 and 13 are 12 is a cross-sectional view and a plan view showing an example of the structure of an optical information recording medium used in the embodiment of FIG. 11. FIG. 1... Semiconductor laser light source, 3... Objective lens, 5...
... Optical detection amount, 20... Optical disk, 21... Phase bit, 22... Magnetic recording film, 100... Head for detecting magneto-optical signal. No. 2 Difth running 5λ”-r Coincidence or season (α) No./2

Claims (1)

[Claims] 1. An optical information recording medium provided with uneven phase pits corresponding to a predetermined information signal, including a substrate on which the phase pits are formed, and a substrate on which at least the phase pits are formed. a magnetic recording film for recording a magneto-optical signal formed on a track with a substantially uniform thickness; An optical information recording medium comprising a coating layer having substantially the same refractive index as that of a substrate. 2. A predetermined wavelength range and a predetermined polarization direction formed with a substantially uniform thickness at any position between the substrate and the magnetic recording film and between the magnetic recording film and the coating layer. 2. The optical information recording medium according to claim 1, further comprising a light beam selection film that selectively reflects only the light beam having one of the above characteristics with a predetermined reflectance. 3. Irradiating the optical information recording medium with a laser beam to record a predetermined information signal, and detecting the information signal recorded on the recording medium from the reflected light and transmitted light of the laser beam from the recording medium. An optical information recording and reproducing device for reproducing information, including a semiconductor laser element and a first photodetector,
an optical head that reproduces a first information signal recorded on the recording medium by the phase pits based on a change in the intensity of the reflected light of the laser beam emitted from the semiconductor laser element on the recording medium; The method includes at least a polarizing element that selectively reflects or transmits only a linearly polarized laser beam, and a second photodetector, and is based on the rotation of the plane of polarization due to the magneto-optical effect of the laser beam transmitted through the recording medium. 1. An optical information recording/reproducing apparatus comprising: a magneto-optical signal detecting head for reproducing a second information signal recorded on a magnetic recording film. 4. The optical information recording and reproducing apparatus according to claim 3, wherein the optical head includes at least first and second semiconductor laser elements that emit laser beams having different wavelengths or polarization directions. 5. The optical head emits the first semiconductor laser element and selectively guides only the first laser beam reflected by the optical information recording medium to a first photodetector in the optical head. The magneto-optical signal detection head has a first wavelength selective filter, and the magneto-optical signal detection head selectively selectively only a second laser beam emitted from the second semiconductor laser element and transmitted through the optical information recording medium. 5. The optical information recording and reproducing apparatus according to claim 4, further comprising a second wavelength selective filter guiding the light to the second photodetector in the magneto-optical signal detecting head. 6. Claim 3, wherein the first and second semiconductor laser elements are housed in one package.
6. The optical information recording and reproducing device according to 4 or 5.