JPH06103630A - Optical recording and reproducing device, optical pickup and laser beam source - Google Patents

Abstract

PURPOSE:To speed up information recording by applying magnetic fields to the circularly polarized light from a laser beam source part to control the rotating direction and irradiating a recording layer with this circularly polarized light, thereby inverting the magnetizations. CONSTITUTION:The active layer 61 and reflection layers 64, 65 of the laser beam source part have axisymmetrical structures and, therefore, the oscillation in both modes of the right-hand circularly polarized light and the left-hand circularly polarized light is possible. The right-hand circularly polarized light and the left-hand circularly polarized light can be changed over in accordance with the directions of the magnetic fields if the magnetic fields are made to act between the layer 61 and the layers 64, 65. Then, the disk is alternately irradiated with the right-hand circularly polarized light and the left-hand circularly polarized light from an optical pickup in accordance with information to be recorded to locally invert the directions of the magnetization of the recording layer to record the information. As a result, the information recording is speeded up.

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, an optical pickup and a laser light source for optically reading / writing information from / to an optical information medium.

[0002]

2. Description of the Related Art Conventionally, various systems have been proposed as a magneto-optical recording / reproducing apparatus.
As described in JP-A-181043, the recording layer of an optical recording medium is irradiated with circularly polarized light to generate a local magnetic field, and whether the rotation direction of the electric vector of the circularly polarized light is clockwise or counterclockwise. There is a method in which recording is performed by switching the direction of the magnetic field generated by, and locally reversing the magnetization direction of the recording layer of the recording medium.

[0003]

In the above prior art, as a means for switching the left and right rotation directions of circularly polarized light, the positional relationship between the polarizer constituting the optical system of the optical head and the 1/4 wavelength plate is mutually changed. It is configured to rotate relative to the optical axis. For this reason, the structure of the means for switching the left and right rotation directions of the circularly polarized light becomes complicated, the device cannot be downsized, and the time for switching the left and right rotation directions of the circularly polarized light increases the speed of information recording and reproduction. There was a problem that it could not be planned.

An object of the present invention is to eliminate the above-mentioned problems of the prior art, and to provide an optical recording / reproducing apparatus, an optical pickup and a laser light source capable of increasing the speed of recording / reproducing information. Especially.

[0005]

In order to achieve the above object, a first invention of the present application is to irradiate a recording film on an optical disk surface with laser light from a laser light source, and to the recording film. In an optical disk device for recording and reproducing information, a driving means for rotating the optical disk, and a laser light source section for emitting circularly polarized light by being scan-driven in the radial direction of the optical disk with a gap from the optical disk surface. An optical recording / reproducing apparatus comprising: an optical pickup having means for applying a magnetic field to the laser light source section in the direction of the optical axis thereof; and an actuator for scanning and driving the optical pickup.

A second invention of the present application is an optical pickup comprising a laser light source section for emitting circularly polarized light and an optical system for condensing the circularly polarized light from the laser light source section. An optical pickup is characterized in that the laser light source section is provided with means for applying a magnetic field in the optical axis direction thereof.

Further, a third invention of the present application is a laser light source provided with a laser light source section for emitting circularly polarized light, wherein a magnetic field is applied to the laser light source section in the optical axis direction thereof. The laser light source is characterized in that means for causing the laser light source is provided.

[0008]

When the laser light source unit for emitting circularly polarized light is provided with means for applying a magnetic field in the direction of its optical axis, the action direction of the magnetic field by the means for applying the magnetic field is changed. The rotation direction of the circularly polarized light emitted from the light source unit can be controlled clockwise or counterclockwise.
By irradiating the recording layer of the optical disk with the clockwise or counterclockwise circularly polarized light, the magnetization of the recording layer can be reversed.

As described above, since the direction of rotation of circularly polarized light can be rapidly changed by changing the action direction of the magnetic field of the means for applying the magnetic field, information recording / reproduction can be speeded up.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a perspective view showing an embodiment of an optical recording / reproducing apparatus of the present invention in a partial cross section. In FIG.
Magneto-optical disk 1 (simply "disk 1" for simplicity
Is referred to as a magnet) and is fixed to the spindle motor 3 by a magnet chuck 2 so that it can be easily attached to and detached from the spindle motor 3. Further, the disk 1 can be rotated by the spindle motor 3. The spindle motor 3 is mounted on the base 15. The carriage 4 is mounted on the rail 6 via a bearing 5,
The disc 1 can be moved in the radial direction of the disc 1 by the course actuator 7, but other movements are restrained. Fine actuator 8
Is mounted on the carriage 4 and includes an optical pickup 9, an objective lens 13 and the like. The fine actuator 8 described above can move the optical pickup 9 and the like relative to the carriage 4 in a direction perpendicular to the disc 1, rotation about an axis in this direction, and three degrees of freedom in the radial direction of the disc 1. .

A command from the outside of the apparatus is input to the system controller 12 of this apparatus via a terminal 11. When an instruction is given from outside the device, the system controller 12
Supplies current to the spindle motor 3 to rotate the disk 1 and also supplies current to the optical pickup 9 to irradiate the disk 1 with light. This light is irradiated onto the disc 1 while being collected by the objective lens 13. From the reflected light of this light, the optical pickup 9 outputs a focus error signal indicating the focus blur on the disk 1 of the focus of the emitted light and a track error indicating a deviation from the track which is a bit string for recording information. Detect the signal. These signals are transmitted via the cable 14 to the system controller 12
Entered in. The system controller 12 supplies a current to the coarse actuator 7 and the fine actuator 8 based on these signals, and moves the optical pickup 9 to irradiate light to a predetermined position on the disc 1. When the command from the outside is recording of information, when the optical pickup 9 moves to a predetermined position, right-handed circularly polarized light and left-handed circularly polarized light are emitted from the optical pickup 9 in accordance with the information to be recorded. The disk 1 is alternately irradiated with light, and information is magnetically recorded on the magnetic film on the disk 1 by utilizing the photo-induced magnetization. When the command from the outside is the reproduction of information, the optical pickup 9 irradiates the disc 1 with linearly polarized light, and reads the information recorded on the disc 1 from the change in the polarization direction of the reflected light. Then, it is output to the outside of the device through the system controller 12 and the terminal 11.

FIG. 2 is an enlarged perspective view showing a fine actuator constituting the apparatus of the present invention. In FIG. 2, the fine actuator 8 for three-dimensionally driving the optical pickup 9 is coils 21, 22, 23 ,. 24, 25
, Magnets 26 and 27, and a yoke 28. Currents can be independently supplied to the coils 21, 22, 23, 24, and 25.

FIG. 3 is a vertical sectional view of an optical pickup which constitutes the apparatus of the present invention. In FIG. 3, the optical pickup 9 includes a package 31, an objective lens 13 attached to the package 31, a substrate 32, and a substrate 32. It is composed of a detection optical system 33 attached to and a piezoelectric element 48.
The substrate 32 has surface emitting laser light source units 34, 35, 3
6, 37, 38 are provided. This laser light source unit 3
The light emitted from 4, 35, 36, 37 and 38 respectively
Focuses 39, 4 on the disc 1 by the objective lens 13.
0, 41, 42, 43 are formed. Usually, an objective lens used in an optical disk device has a tolerance of ± 100 μm. If the size of the laser light source units 34, 35, 36, 37, 38 is set to about 20 μm, even if five laser light source units are lined up, they can be put in the tolerance. The laser light source units 35, 36, and 37 are for recording and reproducing information, and emit circularly polarized light when recording information and linearly polarized light when reproducing information. Further, when recording information, the circularly polarized light can be switched clockwise or counterclockwise. The laser light source units 34 and 38 are for detecting servo signals and emit linearly polarized light regardless of whether information is recorded or reproduced. The light emitted from the laser light source unit 34 passes through the detection optical system 33, is condensed by the objective lens 13, and has a focal point 39.
To form. The light focused on the focal point 39 is reflected by the recording film portion of the disk 1, passes through the objective lens 13 again, and enters the detection optical system 33. Part of this light is the detection optical system 3
The light is diffracted by the diffraction grating 44 provided in No. 3, and enters the photodetector 45. The focus error signal and the track error signal are detected from the light intensity distribution on the photodetector 45. The light emitted from the laser light source unit 38 is detected by the detection optical system 3
After passing through 3, the light is condensed by the objective lens 13 to form a focal point 43. The light condensed at the focal point 43 is reflected by the recording film portion of the disc 1, passes through the objective lens 13 again, and enters the detection optical system 33. A part of this light is diffracted by the diffraction grating 46 provided in the detection optical system 33, and the light detector 47
Incident on. The focus error signal and the track error signal are detected from the light intensity distribution on the photodetector 47. Each of the laser light source units 34, 35, 36, 37, 38 can be turned on and off independently, and information can be recorded / reproduced on / from three tracks at the same time.

FIG. 4 is a cross-sectional view of a fine actuator and an optical pickup constituting the device of the present invention. In FIG. 4, coils 21, 22, 23, 24 and 25 are shown.
And the magnetic field M generated by the magnets 26 and 27.

FIG. 5 is a perspective view for explaining the operation of the focusing mechanism that constitutes the device of the present invention. In FIG. 5, the current A shown in FIG. Since the magnetic field M acts as shown by the arrow in the figure, the upward force F acts on the coil 21. By making the direction of the electric current A opposite, it is possible to exert a downward force F. The force acting on the coil 21 moves the optical pickup 9 in a direction perpendicular to the surface of the disk 1 for focusing.

FIG. 6 is a perspective view for explaining the operation of the tracking mechanism which constitutes the apparatus of the present invention. In FIG. 6, the coils 22 and 23 are supplied with a current A as shown in FIG. 51 works. As shown in FIG. 6, a current A is applied to the coil 24, and an upward current A is applied to a portion of the coil 25 where the magnetic field M of the magnet 27 of FIG. By reversing the currents flowing through the coils 22, 23, 24, 25, the acting forces can be directed in opposite directions. With these forces, the optical pickup 9 is moved to the disc 1
Move in the radial direction of to perform tracking.

FIG. 7 is an explanatory view showing the positional relationship between the focal point and the track in the apparatus of the present invention. The substrate 32 shown in FIG.
When the temperature of the
The spacing of 4, 35, 36, 37, 37 changes. Along with this, the focal points 38, 39, 40, 4 on the disc 1
The interval of 1, 42 changes. When the focal distance changes, for example, when the focal distance increases, a difference occurs between the track error signal detected by the photodetector 45 and the track error signal detected by the photodetector 47. The track servo may be applied to the average value of the track error signal detected by the photodetector 45 and the track error signal detected by the photodetector 47, and the optical pickup 9 may be rotated with respect to the difference.

FIG. 8 is a perspective view for explaining the operation of the optical pickup rotating mechanism that constitutes the device of the present invention.
A force 53 acts by passing a current A through each of 2 and 23 as shown in FIG. As shown in FIG. 8, a current A is applied to the coil 24, and a downward current A is applied to a portion of the coil 25 where the magnetic field M of the magnet 27 shown in FIG. Coil 22,
By reversing the current flowing through 23, 24, 25,
The directions of the acting forces can be opposite. The moment of these forces causes the optical pickup 9 to rotate about the optical axis.

FIG. 9 is an enlarged vertical sectional view showing a laser light source which constitutes the apparatus of the present invention, and shows an operation at the time of recording information. The laser light source units 46 and 47 have the same structure. Photodetectors 70 and 71 are provided on the substrate 32. A reflective layer 65, a conductive layer 63, an active layer 61, and
An insulating layer 66, a conductive layer 62, a reflective layer 64, and a coil 68 are provided. A piezoelectric element 48 is provided on the opposite side of the substrate 32. A current is supplied to the active layer 61 through the electrodes 67, 67 and the conductive layers 62, 63 to emit light. Due to the insulating layer 66, the current is concentrated in the active layer 61, and the carrier density is increased. The active layer 61 is sandwiched between the reflective layers 64 and 65 composed of multilayer thin films,
Light emitted from the active layer 61 travels back and forth between the reflective layers 64 and 65. Of the emitted light, the reflective layer 64,
The mode causing resonance between 65 causes laser oscillation.
Since the laser light source unit 35 has an axially symmetric structure in both the active layer 61 and the reflective layers 64 and 65, laser oscillation is possible in both clockwise circularly polarized light and counterclockwise circularly polarized light modes. By passing a current through the coil 68, a magnetic field can be applied to the active layer 61 and the reflective layers 64 and 65. Active layer 6
1 and the reflective layers 64 and 65 are exposed to a magnetic field, the active layer 6
1. The energy level of electrons in the reflection layers 64 and 65 changes depending on the spin direction. Due to this, the gain of the active layer 61 with respect to light has different values for clockwise circularly polarized light and counterclockwise circularly polarized light. In addition, the reflective layers 64 and 6
The reflectance of 5 has different values for clockwise circularly polarized light and counterclockwise circularly polarized light. That is, the gain of the laser light source unit 35 has different values for clockwise circularly polarized light and counterclockwise circularly polarized light. When causing laser oscillation, the state with the largest gain is selected from among various oscillation states, and oscillation occurs only in this state.
In this case, even if the difference in gain is small, the state in which the gain is the largest is selected, so that the active layer 61 and the reflective layer 64,
By applying a magnetic field to 65 to create a gain difference between the clockwise circularly polarized light and the counterclockwise circularly polarized light, the one with the larger gain can be selectively emitted. Here, the active layer 6
1. By reversing the direction of the magnetic field applied to the reflection layers 64 and 65, it is possible to switch between clockwise circularly polarized light and counterclockwise circularly polarized light. The light emitted from the laser light source has a small emission angle, and it is difficult to downsize the optical pickup 9 when used as it is. A microlens 72 is attached to the detection optical system 33 directly bonded to the substrate 32 by ion diffusion or the like. This lens 72
Thus, the light emitted from the laser light source unit 35 is condensed once, the emission angle is increased, and the optical pickup 9 is downsized. When recording information, the photodetectors 70, 71,
The piezoelectric element 48 is not used.

FIG. 10 is an enlarged vertical sectional view showing a laser light source which constitutes the apparatus of the present invention, and illustrates the operation during information reproduction. In FIG. 10, since the active layer 61 and the reflective layers 64 and 65 have an axially symmetric structure,
It is possible to oscillate in either the clockwise circularly polarized light or the counterclockwise circularly polarized light mode, and at the same time, the linearly polarized light in either the plane of FIG. 10 or the direction perpendicular to the plane of FIG. Therefore, linearly polarized light can be emitted by increasing the gain of light linearly polarized in a specific direction. An electric charge is applied to the piezoelectric element 48 to cause tensile strain in the piezoelectric element 48 in the direction of the arrow. By this,
Strain can be applied to the substrate 32 to which the piezoelectric element 48 is attached. Then, the active layer 61 and the reflective layers 64 and 6
5 is also distorted. At this time, since no current is applied to the coil 68, no magnetic field acts on the active layer 61 and the reflective layers 64 and 65. Then, the gain of the active layer 61 has different values in the direction in which strain is applied and in the direction perpendicular to this. In this case also, the vibration state with the larger gain is selected,
Oscillation occurs with linearly polarized light. The polarization direction of light is either a direction parallel to the strain or a direction perpendicular to the strain. In this case, the same operation is performed regardless of which linearly polarized light oscillates. The operations of the detection optical system 33 and the microlens 72 are as described with reference to FIG. Part of the reflected light from the disk 1 passes through the reflective layer 64, the conductive layer 62, the active layer 61, the conductive layer 63, and the reflective layer 65, and is incident on the photodetectors 70 and 71. The change in the polarization direction of the reflected light is detected by the photodetectors 70, 7
Detected by 1.

As described above, the principle of controlling the rotation direction of circularly polarized light and linearly polarized light will be described below.

When a magnetic field is applied to the active layer of the laser light source, a difference in energy level occurs depending on the spin direction of electrons in the active layer. When the structure of the laser light source is approximately axisymmetric with respect to the optical axis, the gain of the active layer for light differs between clockwise circularly polarized light and counterclockwise circularly polarized light due to this difference in energy level and the law of conservation of angular momentum. Becomes When the laser light source oscillates, a mode in which the oscillation occurs is determined by a slight gain difference. Therefore, when the structure of the laser light source is axisymmetric with respect to the optical axis, circularly polarized light can be obtained by applying a magnetic field to the active layer, and the direction of the magnetic field applied to the active layer is reversed. By doing so, the polarization direction can be reversed.

When a mechanical strain in one direction is applied to the active layer of the laser light source (or when a stress is applied), the motion state of electrons in the active layer depends on the strain (or stress) direction. It becomes different in the direction perpendicular to it, and causes a difference in the wave function of the electron. Then, the gain of the active layer with respect to the light has different values depending on whether the polarization direction of the light is parallel to or perpendicular to the strain (or stress).
When the laser light source oscillates, the mode in which the oscillation occurs is determined by the slight difference in gain. Therefore, even if the structure of the laser light source is axisymmetric with respect to the optical axis, it is biased in one direction by applying strain (or applying stress) to the active layer in one direction perpendicular to the optical axis. Linearly polarized light can be emitted.

When an electric field is applied to the active layer of the laser light source in a certain direction, the motion state of electrons in the active layer becomes different between the direction of the electric field and the direction perpendicular thereto, and the wave function of the electron is changed. Make a difference. Then, the gain of the active layer with respect to the light has different values depending on whether the polarization direction of the light is parallel to or perpendicular to the electric field. When the laser light source oscillates, the mode in which the oscillation occurs is determined by the slight difference in gain. Therefore, even if the structure of the laser light source is axisymmetric with respect to the optical axis, by applying an electric field to the active layer in one direction perpendicular to the optical axis, linearly polarized light polarized in one direction is generated. Can be emitted.

FIG. 11 is a perspective view showing a partial cross section of a laser light source which constitutes the device of the present invention, in which tensile strain is applied in the x-axis direction. The emitted light is x
It becomes linearly polarized light in either the axial direction or the y-axis direction.
Since the same operation is performed regardless of which polarization is used, the operation will be described here as being polarized in the x-axis direction. The substrate 32 is an N-type semiconductor, and the photodetector 7
0 and 71 are made of a P-type semiconductor and have PN junctions. This portion operates as a photodiode. The electron motion state differs between the direction parallel to the PN junction and the direction perpendicular thereto, and the sensitivity of the photodiode also has different values depending on whether the polarization direction of the incident light is parallel to the PN junction or perpendicular. Which is more sensitive, parallel or vertical, depends on the composition of the semiconductor, the magnitude of the reverse bias, and the wavelength of the incident light, but it is important here that there is a difference. And it doesn't really matter which one is bigger. Here, it is assumed that the sensitivity is higher when the polarization direction is perpendicular to the PN junction surface than when it is parallel.
The opposite case works exactly the same. Photodetector 70
Has a PN junction surface perpendicular to the ξ axis in FIG. 12, and in the photodetector 71, the PN junction surface is perpendicular to the η axis. When the polarization direction of the light incident on the photodetectors 70 and 71 is parallel to the x-axis, the photodetectors 70 and 71 corresponding to the polarization direction of this light are detected.
The angles formed by the PN junction surfaces of are equal, and the photodetectors 70 and 71 have the same sensitivity to this light. The light reflected by the disc 1 is polarized in the direction indicated by the vector 101 and the direction indicated by the vector 102 in FIG. 12 depending on whether the magnetization direction of the magnetic film on the disc 1 is the upward direction or the downward direction. Direction indicated by vector 101 and photodetector 7
The angle formed by the 1 PN junction surface is closer to the vertical than the angle formed by the PN junction surface of the photodetector 70. Therefore, the vector 101
The sensitivity to light polarized in the direction indicated by
1 is larger than the photodetector 70. Similarly, the photodetector 70 has a higher sensitivity to light polarized in the direction indicated by the vector 102 than the photodetector 71. In this way, by comparing the output of the photodetector 70 and the output of the photodetector 71, the polarization direction of the reflected light from the disc 1 can be detected.

FIG. 13 is a vertical cross-sectional view of another portion of the laser light source section which constitutes the device of the present invention.
A cross-sectional view of the photodetector 45 and the diffraction grating 44 is shown. The laser light source unit 38, the photodetector 47, and the diffraction grating 46 have the same structure. The laser light source unit 34 has a structure in which there is no coil for applying a magnetic field, and the active layer 61 and the reflective layers 64 and 65 have an elliptic structure.
Same as 5. Since the structure is not axially symmetric, the emitted light is linearly polarized light that is deviated in the major axis or minor axis direction of the ellipse. The light emitted from the laser light source unit 34 is condensed once by the microlens 72 provided on the detection optical system 33, and is emitted with a large emission angle. Disk 1
A part of the reflected light from is diffracted by the diffraction grating 44 and is condensed at the position of the photodetector 45. As shown in FIG. 14, the diffraction grating 44 is formed at an angle of about 45 degrees with respect to the direction of the track T. The photodetector 45 is composed of four photodiodes 81, 82, 83, 84 as shown in FIG. The light diffracted by the diffraction grating 44 has astigmatism. Therefore, when the disc 1 is far from the objective lens, the pattern of spots P is as shown in FIG. 15, and when it is close, the pattern of spots P is as shown in FIG. Therefore, the photodiode 8
When the outputs of 1, 82, 83, and 84 are a, b, c, and d, respectively, a focus error signal is obtained by performing a process of (a + c)-(b + d). In a normal magneto-optical disk, the track portion is a groove. Therefore, when a deviation from the track occurs, the amount of light incident on the photodiodes 82 and 83 and the amount of light incident on the photodiodes 81 and 84 relatively change due to the influence of groove diffraction. Therefore, (b + c)-(a +
By performing the process of d), a track error signal is obtained.

FIG. 17 shows another embodiment of the laser light source section constituting the device of the present invention. In this figure, the active layer 6
1, conductive layers 62 and 63, reflective layers 64 and 65, electrodes 67,
69, the coil 68, the insulating layer 66, the structure of the piezoelectric element 48,
The operation is similar to that of the embodiment described with reference to FIGS. The photodetectors 70 and 71 are not under the reflection layer 65, but are provided on the surface of the substrate 32, and the detection optical system 33 is provided with a diffraction grating 91 that diffracts the reflected light from the disc 1. The difference is that In this case, the distance between the laser light source units can be narrowed by making the direction of diffraction by the diffraction grating 91 substantially coincide with the direction of the track.

18 and 19 show still another embodiment of the laser light source section constituting the apparatus of the present invention, and FIG. 18 shows the operation at the time of recording information. In FIG. 18, the active layer 61, the conductive layers 62 and 63, the reflective layers 64 and 6 are shown.
5, the electrodes 67 and 69, and the coil 68 have the structures shown in FIGS.
This is the same as the case of the embodiment described using. The difference is that the piezoelectric element 48 is not provided and the electrodes 92 and 93 are embedded in the insulating layer 66. During recording of information, no potential difference is applied to the electrodes 92 and 93, a current is passed through the coil 68, and a magnetic field is applied to the active layer 61 and the reflective layers 64 and 65. By switching the direction of the current flowing through the coil 68, the polarization direction of the emitted light can be switched between clockwise circular polarization and counterclockwise circular polarization.

FIG. 19 shows an operation at the time of reproducing information. When reproducing information, no current is passed through the coil 68, a potential difference is applied to the electrodes 92 and 93, and an electric field is applied to the active layer 61. As shown in FIG. 20, when a negative potential is applied to the electrode 92 and a positive potential is applied to the electrode 93, the active layer 6
The electrons and holes of 1 are attracted to the electrodes 93 and 92, respectively, and the carrier distribution is unbalanced. For this reason, the wave function of the electron also differs between the direction in which the electric field is applied and the direction perpendicular to this.
In this case, the gain of the active layer 61 with respect to light has different values depending on whether the polarization direction is parallel to or perpendicular to the direction of the electric field, and linearly polarized light with a large gain is emitted. The method of detecting the polarization direction of the reflected light from the disc 1 is the same as that of the embodiment described with reference to FIGS.

As described above, according to the embodiment of the present invention, the laser light source section for emitting circularly polarized light is provided with means for controlling the rotation direction of circularly polarized light by applying a magnetic field in the optical axis direction thereof. ,
By this means, the circularly polarized light is applied to the recording layer of the disc to reverse its magnetization, and information is written, and
Since the laser light source unit is provided with means for applying stress or mechanical strain in a direction orthogonal to its optical axis and circularly polarized light can be irradiated onto the recording layer of the disc as linearly polarized light, information can be read out. Playback can be speeded up. Further, since the above-mentioned means can be arranged in the laser light source section, the number of parts can be greatly reduced and the size can be reduced.

In the above embodiment, the laser light source section is provided with a coil as a means for applying a magnetic field. However, a permanent magnet is rotatably provided in the laser light source section. The direction of the magnetic field may be changed by rotating the.

[0033]

According to the present invention, circularly polarized light from the laser light source section is applied with a magnetic field in the direction of its optical axis to control the rotation direction of the circularly polarized light, and this circularly polarized light is applied to the recording layer of the disc. Then, since the magnetization can be reversed, the speeding up of information recording can be greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an optical recording / reproducing apparatus of the present invention in a partial cross section.

FIG. 2 is an enlarged perspective view showing a fine actuator that constitutes the device of the present invention.

FIG. 3 is a vertical cross-sectional view of an optical pickup that constitutes the device of the present invention.

FIG. 4 is a transverse cross-sectional view of a fine actuator and an optical pickup that form the device of the present invention.

FIG. 5 is a perspective view illustrating the operation of a focusing mechanism that constitutes the device of the present invention.

FIG. 6 is a perspective view illustrating the operation of a tracking mechanism that constitutes the device of the present invention.

FIG. 7 is an explanatory diagram showing a positional relationship between a focus and a track in the device of the present invention.

FIG. 8 is a perspective view for explaining the operation of the optical pickup rotation mechanism that constitutes the device of the present invention.

FIG. 9 is an enlarged vertical cross-sectional view showing a laser light source that constitutes the device of the present invention, and illustrates the operation during information recording.

FIG. 10 is an enlarged vertical cross-sectional view showing a laser light source that constitutes the device of the present invention, and illustrates an operation during information reproduction.

FIG. 11 is a perspective view showing a partial cross section of a laser light source that constitutes the device of the present invention.

FIG. 12 is an explanatory diagram of a method for detecting the polarization of reflected light in a laser light source that constitutes the device of the present invention.

FIG. 13 is a vertical cross-sectional view of another portion of the laser light source that constitutes the device of the present invention.

FIG. 14 is an explanatory diagram of a diffraction grating and a photodetector in the laser light source that constitutes the device of the present invention.

FIG. 15 is an explanatory diagram showing an example of a spot pattern on a photodetector in a laser light source that constitutes the device of the present invention.

FIG. 16 is an explanatory diagram showing another example of the spot pattern on the photodetector in the laser light source that constitutes the device of the present invention.

FIG. 17 is a longitudinal sectional view showing another embodiment of the laser light source that constitutes the device of the present invention.

FIG. 18 is a vertical cross-sectional view showing still another embodiment of the laser light source that constitutes the device of the present invention, and illustrates the operation at the time of recording information.

FIG. 19 is a vertical cross-sectional view for explaining the operation at the time of reproducing information in still another embodiment of the laser light source that constitutes the device of the present invention shown in FIG.

FIG. 20 is an enlarged sectional view showing an active layer in a laser light source that constitutes the device of the present invention.

[Explanation of symbols]

1 ... Magneto-optical disk, 2 ... Magnet chuck, 3 ... Spindle motor, 4 ... Carriage,
5 ... Bearing, 6 ... Rail, 7 ... Course actuator, 8 ... Fine actuator, 9
... Optical pickup, 11 ... Terminal, 12 ... System controller, 13 ... Objective lens, 14 ...
・ Cable, 21, 22, 23, 24, 25 ... Coil, 26, 27 ... Magnet, 28 ... Yoke,
31 ... Package, 32 ... Substrate, 33 ... Detection optical system, 34, 35, 36, 37, 38 ... Surface emitting laser light source section, 39, 40, 41, 42, 43 ... Focus, 44 ... Diffraction grating, 45 ... Photodetector, 46 ...
..Diffraction gratings, 47 ... Photodetectors, 51, 52, 5
3, 54 ... Force, 61 ... Active layer, 62, 63 ...
-Conductive layer, 64, 65 ... Reflective layer, 66 ... Insulating layer, 67 ... Electrode, 68 ... Coil, 69 ... Electrode, 70, 71 ... Photodetector, 72 ... ..Microlenses, 81, 82, 83, 84 ... Photodiodes, 91 ... Diffraction gratings, 92, 93 ... Electrodes

Continuation of the front page (72) Inventor Katsuhiko Kimura 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture

Claims (16)

[Claims] 1. An optical recording / reproducing apparatus for irradiating a laser beam from a laser light source onto a recording film on the surface of an optical disk to record / reproduce information on / from the recording film; A laser light source unit that emits circularly polarized light by being scanned and driven in the radial direction of the optical disc with a space from the optical disc surface, and means for applying a magnetic field to the laser light source unit in the optical axis direction thereof are provided. An optical recording / reproducing apparatus comprising an optical pickup and an actuator for scanning and driving the optical pickup. 2. The optical recording / reproducing apparatus according to claim 1,
The laser light source unit and the means for applying the magnetic field are:
Substrate, active layer provided on the substrate to emit light by passing current, electrode for supplying current to the active layer, and means for applying a magnetic field in the direction of light propagating in the active layer An optical recording / reproducing apparatus comprising: 3. The optical recording / reproducing apparatus according to claim 3,
The optical recording / reproducing apparatus, wherein the means for applying the magnetic field is a coil. 4. The optical recording / reproducing apparatus according to any one of claims 1 to 3, wherein the laser light source section is provided with means for applying a stress or mechanical strain in a direction orthogonal to the optical axis thereof. Recording / playback device. 5. An optical recording / reproducing apparatus for irradiating a laser light from a laser light source onto a recording film on the surface of an optical disk to record / reproduce information on / from the recording film, and a drive means for rotating the optical disk. A laser light source unit that is driven to scan in the radial direction of the optical disc with a space from the optical disc surface and emits circularly polarized light, and means for switching the polarization direction of circularly polarized light by applying a magnetic field to the laser light source unit. An optical recording / reproducing apparatus comprising: an optical pickup having the same; and an actuator for scanning and driving the optical pickup. 6. An optical pickup comprising a laser light source section for emitting circularly polarized light and an optical system for condensing the circularly polarized light from the laser light source section. An optical pickup comprising means for applying a magnetic field in the optical axis direction. 7. The optical pickup according to claim 6,
The laser light source unit and the means for applying the magnetic field are:
A substrate, an active layer that is provided on the substrate and that emits circularly polarized light by passing a current, a power supply that supplies a current to the active layer, and a magnetic field that acts in the direction of light propagating in the active layer. An optical pickup having means for causing the optical pickup. 8. The optical pickup according to claim 6,
An optical pickup, wherein the means for applying the magnetic field is a coil. 9. The optical pickup device according to claim 6, further comprising means for applying a stress or a mechanical strain in a direction orthogonal to an optical axis of the laser light source unit. . 10. An optical pickup comprising a laser light source section for emitting circularly polarized light and an optical system for concentrating the circularly polarized light from the laser light source section. An optical pickup comprising means for applying a magnetic field to switch the polarization direction of circularly polarized light. 11. A laser light source provided with a laser light source section for emitting circularly polarized light, characterized in that the laser light source section is provided with means for applying a magnetic field in the optical axis direction thereof. Laser light source. 12. The laser light source according to claim 11,
The laser light source unit and the means for applying the magnetic field are:
A substrate, an active layer that is provided on the substrate and that emits circularly polarized light by passing a current, a power supply that supplies a current to the active layer, and a magnetic field that acts in the direction of light propagating in the active layer. A laser light source, which is provided with: 13. A laser light source according to claim 12,
The laser light source characterized in that the means for applying the magnetic field is a coil. 14. A laser light source according to claim 11, wherein said laser light source portion is provided with means for applying stress or mechanical strain in a direction orthogonal to its optical axis. Light source device. 15. A laser light source provided with a laser light source section for emitting circularly polarized light, wherein the laser light source section is provided with means for switching the polarization direction of circularly polarized light by applying its magnetic field. Characterized laser light source. 16. An optical recording / reproducing apparatus for irradiating a laser light from a laser light source to a recording film on an optical disk surface to record / reproduce information on / from the recording film, a driving means for rotationally driving the optical disk. And an optical pickup that floats on the surface of the optical disk by the lift of the optical disk, wherein the optical pickup has a laser light source section that emits circularly polarized light and an optical axis direction of the laser light source section. An optical recording / reproducing apparatus having means for applying a magnetic field to the.