JPH03260934A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and/or reproduce either optical recording media of two kinds having different thickness from each other for their light-transmittive covers and to make the optical recording media interchangeable between them by providing a translucent compensation plate having a prescribed thickness between an objective lens and the 2nd optical recording medium. CONSTITUTION:The thickness t2 of the light-transmittive cover of a double-sided medium 43 is constituted thinner than the thickness of a light-transmittive cover of a single-sided medium. The double-sided medium 43 is mounted on a rotary disk with its upper surface A opposite to the side of a 2nd optical system 21 and with its lower surface B opposite to the side of a 1st optical system 1. The translucent compensation plate (1st optical glass plate) 28 is disposed between the objective lens 2 of the 1st optical system 1 and the lower surface B of the double-sided medium 43, and the sum of its thickness t3 and the thickness t2 of the translucent cover of the double-sided medium 43 is equalized with the thickness of the light transmittive cover of the single-sided medium. When the single-sided medium is to be recorded and reproduced, its translucent cover is mounted on the side of the 1st optical system 1, and the operation is performed under the state of removing the translucent compensation plate 28 from between the objective lens 2 and the translucent cover.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical recording and reproducing apparatus capable of recording and/or reproducing information on an optical recording medium.

[Summary of the invention]

The optical recording/reproducing device of the present invention is capable of recording and/or recording information on the first optical recording medium having a thicker transparent cover, in first and second optical recording media having transparent covers having different thicknesses. Alternatively, when recording and/or reproducing the second optical recording medium having a thinner transparent cover using an optical system having an objective lens configured to enable reproduction, the objective lens By adding a light-transmitting compensating plate between the objective lens and the second optical recording medium to compensate for aberrations in the lens, the first and second lenses are provided with light-transmitting covers having different thicknesses. This allows recording and/or reproduction of any of the two optical recording media.

[Conventional technology]

FIG. 5 shows a magneto-optical recording and reproducing apparatus using a magneto-optical recording medium as an example of an optical recording and reproducing apparatus for recording and/or reproducing on an optical recording medium.

The conventional magneto-optical recording and reproducing apparatus shown in FIG. In addition, a magnetic field generating device 60, which is a magnetic system, is provided on the upper surface side of the single-sided magneto-optical recording medium 50. Numerical aperture of objective lens 59 (rN
AJ) is set to about 0.50 to 0.53.

Further, a drive system (not shown) is provided to drive the optical system in the focusing direction and the tracking direction regarding the single-sided magneto-optical recording medium 50.

As for the magnetic system, another drive system (not shown) is provided for driving the magnetic system in the arrow direction in FIG. 5 and in the above-mentioned tracking direction.

This magneto-optical recording/reproducing device employs a magnetic field modulation method for recording. In this magnetic field modulation method, it is necessary to control the magnetic field to be reversed at high speed, so a sufficient excitation current cannot be obtained, and there is a limit to the generated magnetic field strength.
The magnetic field generating device 60 is disposed near a recording magnetic layer 53, which will be described later, in the single-sided magneto-optical recording medium 50. According to the magnetic field modulation method, overwriting (overwriting) is possible.

On the other hand, the -h tile-arranged surface magneto-optical recording medium 50 has a dielectric layer 52, such as a rare earth-transition metal alloy amorphous thin film, which has a large magneto-optic effect, on one side of a transparent cover 51 made of polycarbonate or the like. A recording magnetic layer 53, a dielectric layer 54, a reflective layer 55, and a protective cover 56 are laminated in this order. In this case, the thickness t of the translucent cover 51 is constant, and has conventionally been set to 1.2 mm.

Next, a brief explanation of the operation will be given.

First, the single-sided magneto-optical recording medium 50 is placed on a rotating disk (not shown) and driven to rotate, and a magnetic field from the magnetic field generating bag W60 is applied to the S3 magnetic layer 53 in the single-sided magneto-optical recording medium 50. This applied magnetic field is controlled at high speed,
The laser device 5
By focusing the laser beam irradiated from 8 through the objective lens 59 and the transparent cup 51, the recording magnetic layer 53 in the area where the laser beam is focused can be magnetized, and information signals can be recorded in real time. can be overridden.

By the way, the situation in recent years! With the increase in the amount of magnetic flux, double-sided magneto-optical recording media have been developed that are equipped with the above-mentioned recording magnetic layers on both sides of a single magneto-optical recording medium so that information signals can be recorded on both sides. .

However, in order to perform recording and/or reproduction on such a double-sided magneto-optical recording medium, for example, a magneto-optical bissoqua knob configured by integrating an optical system and a magnetic system as shown in FIG. Re-written via optical Ka<-S,? :
It is extremely difficult to apply a magnetic field with sufficient strength to the magnetic layer. In a magnetic field generation device using magnetic field modulation, a high-frequency current corresponding to a high-frequency data signal must be passed through the electromagnetic coil, but the higher the frequency, the more difficult it is for the current to flow through the coil, so there is a limit to the generated magnetic field. This is because, as mentioned above, the distance from the magnetic field generator to the recording magnetic layer via the light-transmitting cover is quite large. Therefore, double-sided magneto-optical recording using the magnetic field modulation method is extremely difficult with the current technology.

Note that the objective lens 59 is corrected for spherical aberration W4G expressed by the following equation.

W4゜=t/8・((N”-1)/N3)・NA
' (1,) (N: refractive index of the objective lens; t: thickness of the transparent cover of the optical recording medium) (Problem to be solved by the invention) By the way, the thickness of the transparent cover of the optical recording medium As mentioned above, t has been set to 1.2 mm, but this is only a customary setting, and technically 1.2 mm
It doesn't have to be.

Here, when the thickness t of the transparent cover becomes thinner, for example, in the above-mentioned magneto-optical recording/reproducing device, the distance between the magnetic field generator 60 and the recording magnetic layer 53 (the distance between the transparent cover 5
This is preferable because the distance (via 1) becomes shorter. That is, a larger magnetic field can be applied to the recording magnetic layer 53 from the transparent cover 51 side.

As mentioned above, the objective lens in an optical system is required to correct spherical aberration, but as can be seen from the above formula (fl), even if N and NA are constant, the correction value is determined by the amount of light transmitted through the optical recording medium. It varies depending on the thickness t of the cover.

For example, the thickness t of the translucent cover is 1゜2 m as in the conventional case.
In the case of t, the spherical aberration is corrected in the objective lens of the optical system based on t.

On the other hand, if the thickness t of the transparent cover of another optical recording medium is, for example, 1.2u or less for the above-mentioned purpose, recording and/or reproduction on this optical recording medium may be
Correction of spherical aberration based on the thickness of the transparent cover (x) cannot be performed by an optical system with an objective lens.

As shown in Figure 2 below, the thickness of the translucent cover is 1
．． Conventional optical recording and reproducing apparatuses have not been compatible with optical recording media with a thinner transparent cover and optical recording media with a thinner transparent cover. Therefore, it can be very inconvenient when using both optical recording media.

The object of the present invention is to provide two transparent covers with different thicknesses.
It is an object of the present invention to provide an optical recording and reproducing device that is compatible and can perform recording and/or reproduction on any type of optical recording medium.

[Means to solve the problem]

In order to achieve the above object, the optical recording and reproducing apparatus of the present invention includes a recording layer that is irradiated with a laser beam for recording and/or reproduction, a recording layer that is provided to cover this recording layer, and a laser beam that is irradiated with the laser beam for recording and/or reproduction. In the first and second optical recording media, the first and second optical recording media are provided with a translucent cover through which the first
The thickness of the light-transmitting cover of the optical recording medium is thicker than the light-transmitting cover of the second optical recording medium, and the laser beam is focused on the recording layer through the light-transmitting cover. and an optical system having an objective lens configured to be capable of recording and/or reproducing the first optical recording medium, and an optical system configured to perform recording and/or reproducing the second optical recording medium. It is characterized by comprising a light-transmitting compensating plate added between the objective lens and the second optical recording medium in order to compensate for aberrations in the objective lens.

[Effect]

The objective lens in the optical system is configured to perform recording and/or recording on a first optical recording medium having a thicker transparent cover.
Or it is configured so that it can be played back.

When the objective lens performs recording and/or reproduction on the second optical recording medium whose transparent cover has a thinner thickness, a transparent compensating plate of a predetermined thickness is connected to the objective lens and the optical recording medium. When added between the second optical recording medium and the second optical recording medium, the apparent thickness of the thinner transparent cover on the second optical recording medium increases. Aberrations caused by the thinner thickness of the optical cover can be compensated for. Therefore, it is possible to record and/or reproduce data on both the first and second optical recording media using the optical system.

〔Example〕

Embodiments according to the present invention will be described below with reference to FIGS. 1 to 4B.

FIGS. 1 and 2 are cross-sectional views showing the schematic structure of the magneto-optical recording and reproducing apparatus of this embodiment.

FIG. 1 shows the case where recording and reproduction are performed on a double-sided magneto-optical recording medium 43 (hereinafter referred to as "double-sided medium") in the magneto-optical recording and reproducing apparatus of this embodiment. Second
The figure shows a case in which recording and reproduction are performed on a single-sided magneto-optical recording medium 50 (hereinafter referred to as a "single-sided medium") shown in FIG. 5 in the same magneto-optical recording and reproducing apparatus as in FIG. 1.

0 The magneto-optical recording and reproducing apparatus shown in FIG. 1 includes a first optical system 1,
A first optical system (not shown) for driving this first optical system 1
a drive system, a magnetic head 29 constituting a first magnetic system, a first optical glass plate 28 on which this magnetic head 29 is formed and for performing aberration compensation, and a second optical system 21.
, a second drive system (not shown) for driving the second optical system 21, and a magnetic head 19 constituting the second magnetic system.
, a second optical glass plate 18 on which the magnetic head '19 is formed, a rotation shaft 37a, and a spindle motor 37 for rotating the magneto-optical recording medium.

As described above, in the magneto-optical recording and reproducing apparatus of this embodiment, two magneto-optical pink amplifier devices consisting of an optical system, a magnetic system and a drive system are connected via a magneto-optical recording medium to the top and bottom in FIGS. 1 and 2. They are equipped with each.

Note that the magneto-optical recording and reproducing apparatus of this embodiment is configured so that overwriting can be performed using a magnetic field modulation method.

The first optical system 1 includes a first optical system for focusing a laser beam.
, an objective lens 2 , a polarizing heam beam stabilizer 3 , a collimator lens 4 , a cylindrical lens 5 , a laser diode 11 , and a photodetector 12 .

The first optical system 1 is capable of recording and reproducing the single-sided medium 50 described above, which has a transparent cover 51 whose thickness t is set to 1.2 mm as shown in FIG. It is configured so that it can be done.

The first objective lens 2 is capable of correcting the spherical aberration obtained as t=lJu in the above-mentioned 2(1). Note that, in the above value of t, since the thickness of the dielectric layer 52 of the single-sided medium 50 is considerably smaller than 1.2n+m, there is no need to take it into consideration.

The second optical system 21 is arranged to face the first objective lens 2 and includes a second objective lens 22 for focusing the laser beam, a polarizing beam splitter 23, a collimator lens 24, and a cylindrical lens 25. , a laser diode 31, and a photodetector 32, respectively.

1 2 The above-mentioned double-sided medium 43 shown in FIG. A high magnetic permeability layer 45, a photocurable resin N46, a magneto-optical recording layer 47, an adhesive layer 48, and a light-transmitting protective plate 49 are laminated in sequence on both sides of the base 44, respectively.

Both the protective plate 49 and the adhesive layer 48 on one surface (the upper surface in FIG. 1) A and the other surface (the lower surface in FIG. 1) B of the double-sided medium 43 have translucency and do not allow the laser beam to pass through them. The sum t2 of their thicknesses is 1.
It can be set to 2+u or less, for example, 0.5 mm.

The high magnetic permeability layer 45 is made of a material having high magnetic permeability, such as transition metals such as Fe, Co, and Ni, and alloys thereof such as permalloy, sendust, or amorphous magnetic alloy, and has both sides. It becomes possible to increase the perpendicular magnetic field efficiency in the direction perpendicular to the medium 43.

The second optical system 21 is configured to be capable of recording and reproducing the double-sided medium 43 described above.

The NA of the second objective lens 22 is set to be the same as the NA of the first objective lens 2, and correction of the spherical aberration, which is determined as, for example, t = 0.5 m11 in the above equation (1). is hollowed out.

In addition, in the correction of this spherical aberration, the second
The thickness of the optical glass plate 18 can be considered as necessary.

As described above, in the first objective lens 2 and the second objective lens 22, since the radius in the above equation (1) is different from each other, the correction values for spherical aberration are different from each other. Therefore, the double-sided magneto-optical recording medium 43 is
When recording and reproducing on the lower surface B side, since spherical aberration occurs without being corrected in the first objective lens 2, it is necessary to compensate for this spherical aberration.

For the above-mentioned compensation, a first optical glass plate 28 is added between 3 4 of the lower surface B of the double-sided medium 43 and the first objective lens 2 . The first optical glass 28 can be made of a light-transmitting material, such as quartz, but is not limited thereto, and may be made of any light-transmitting material.

Also, the thickness t of the first optical glass plate 28.

When this first optical glass plate 28 is added as described above, the adhesive 1'i48 of the double-sided medium 43 and the protective plate 49
The sum of the thicknesses t2 is the thickness 1. of the transparent cover 51 of the single-sided medium 5o. is determined to be approximately equal to . That is, 12+13=1. is designed to be practically intimidating. By adding the first optical glass plate 28 having a plate thickness t3, t2 is apparently increased by t and l, and becomes t.
Since it is approximately equal to l, the spherical aberration in the first objective lens 2 is appropriately corrected as in the case of the single-sided medium 50.

The second optical glass plate 18 in the second optical system 21 is
It is arranged between the upper surface A of the double-sided medium 43 and the second objective lens 22 so as to be in contact with the second objective lens 22, and is made of a light-transmitting material such as the same as the first optical glass 28 described above. It can be composed of quartz, etc.

Note that the thickness of the second optical glass plate 18 is thinner than that of the first optical glass plate 28. Further, if necessary, the spherical aberration can be corrected in advance in the second objective lens 22 according to the above formula (1), taking into consideration the thickness of the second optical glass plate 18. Further, the second optical glass plate 18 may be provided with a hole through which the laser beam passes in order to prevent reflection. There is no need to take this into account when correcting spherical aberration.

As shown in FIG. 3, - the surface 18a of the second optical glass plate 18 is provided with a conductor 1 for passing a current of a high frequency signal to generate a magnetic field in order to constitute a magnetic hand 19;
7a is formed as a spiral coil pattern 17. On the back surface 18b of the optical glass 18 on which the coil pattern 17 is not formed, the optical glass 18 and the second objective lens 22 are aligned so that the center of the coil pattern 17 and the center of the second objective lens 22 coincide objective lens 22
are fixed with adhesive.

Similar to the second optical glass plate 18, on the surface 28a of the first optical glass plate 28, a conductor 27a is formed as a spiral coil pattern 27 to constitute a magnetic head 29. On the back surface 28b of the optical glass plate 28, the center of the coil pattern 27 and the first objective lens 2
The first optical glass plate 2B and the first objective lens 2 are fixed so that they are aligned so that their centers coincide with each other, and the first objective lens 2 is in contact with the first optical glass plate 2B. This first optical glass plate 28 is designed to be removed when recording and reproducing the single-sided medium 50.

The optical glass plates 18 and 28 have surfaces 18a and 28 on which the coil patterns 17 and 27 are formed, respectively.
They can be arranged so that a is close to the upper surface A and the lower surface B of the double-sided medium 43, respectively.

As described above, the first optical glass plate 28 has a coil pattern 27 for aberration compensation and for the magnetic head 29.
It is also used to provide a.

Next, the operation will be explained.

First, the case of recording on the double-sided medium 43 will be explained.

As shown in FIG. 1, the upper surface A of the double-sided medium 43 is
mounted on a rotating disk (not shown) on the optical system 21 side of the optical system 21 so that its lower surface B faces the first optical system 1 side, respectively;
It is rotated by a spindle motor 37. In addition, double-sided media 4
The top surface (one surface) A and the bottom surface (the other surface) B of 3 are the first
It may be upside down in the figure.

At the same time, the first optical system 1 is moved along with the first optical glass plate 28 by the first drive system (not shown) to move the arrow F in FIG.
The first objective lens 2 is driven and displaced in the focus direction which is the optical axis direction of the first objective lens 2. Further, it is driven and displaced in the tracking direction, which is a direction perpendicular to the optical axis of the objective lens 2, which is not shown under the arrow in FIG. Furthermore, the second optical system 21
A second drive system (not shown) moves the first optical system 1 in the F direction and the downward direction together with the optical glass plate 18.
are respectively driven and displaced in synchronization with the above driving.

7 8 At the same time, a high frequency current signal, which is an amplified signal to be recorded, is supplied to the coil pattern 27 of the magnetic head 29 provided on the first optical glass plate 28 on the lower surface B side of the double-sided medium 43. A magnetic field is generated. This magnetic field is controlled to be reversed at high speed according to the recording signal, and is applied to the magneto-optical recording layer 47 on the lower surface B side of the double-sided medium 43.

Then, the laser beam irradiated from the laser diode 11 is applied to the region of the magneto-optical recording layer 47 to which the magnetic field is applied, and the laser beam is transmitted through the collimator lens 4, the polarizing beam splitter 3, the first objective lens 2, and the first optical glass plate. via 28,
Furthermore, the transparent protection plate 49 and adhesive layer 4 of the double-sided medium 43
Focus through 8. Information signals can be recorded by raising the temperature of the magneto-optical recording layer 47 above the Curie point.

Also, on the upper surface A side of the double-sided medium 43, a magnetic field is generated by supplying a current signal to the coil pattern 17 of the magnetic head 19 provided on the second optical glass plate 18 in the same manner as described above. Top surface A of double-sided medium 43
The voltage is applied to the magneto-optical recording layer 47 on the side. Then, the lower surface B mentioned above (!Similar to 1.11, the laser beam from the laser diode 31 is transmitted to the collimator lens 24, the polarizing beam splitter 23, the second objective laser beam 22, the second optical glass plate 28, the double-sided medium Recording is performed by focusing the above-mentioned magnetic field on the magneto-optical recording layer 47 through the transparent protective plate 49 and the adhesive layer 48, respectively.

Further, when reproducing the information signal recorded on the lower surface B of the double-sided medium 43, the laser beam is transmitted to the laser diode 1.
1, the light is irradiated with a lower output intensity than during recording, and is focused on the magneto-optical recording layer 47. Then, the light reflected from the magneto-optical recording layer 47 follows a path opposite to that of the incident light and is directed by the polarizing beam splitter 3 to the cylindrical lens 5.
is guided to the photodetector 12 via. The intensity of this light changes due to the magneto-optic effect in the magneto-optical recording layer 47, and reproduction is performed by reading this change with the photodetector 12.

90 Further, reproduction on the upper surface A of the double-sided medium 43 is performed in the same manner as on the lower surface B side described above.

As shown in Figure 2, it is thicker than the conventional one (e.g. 1.2n).
Using the first objective lens 2 for recording and reproducing a single-sided medium 50 having a light-transmitting cover 51, a thinner light-transmitting cover (protective plate 49 and adhesive layer) through which the laser beam passes is used. Recording and reproduction on the lower surface B side of the double-sided medium 43 having the double-sided medium 48) can be performed by adding the first optical glass plate 28 as described above. Therefore, recording and reproduction can be performed on both sides A and B of the double-sided medium 43.

Further, the first objective lens 2 and the first optical glass plate 28 are placed on the lower surface B side of the double-sided medium 43, and the second objective lens 22 and the second optical glass plate 18 are placed on the upper surface A side of the double-sided medium 43. Coil patterns 27.17 provided on the first and second optical glass plates 28.18, respectively.
are close to the lower surface B and upper surface A of the double-sided medium 43, respectively. Further, the thickness t2 of the translucent cover composed of the adhesive layer 48 and the protection plate 49 through which the laser beam passes is smaller. Therefore, since the distance between each of the coil patterns 27.17 constituting the magnetic head 29.19 and the magneto-optical recording layer 47 of the double-sided medium 43 can be extremely shortened, magneto-optical modulation, which was previously considered to be extremely difficult, can be achieved. This method enables recording on double-sided magneto-optical recording media.

Furthermore, the magnetic heads 29 and 19 are fixed to the first and second objective lenses 2.22, respectively, and are linked to the T-direction claw servo of these objective lenses 2.22, so that the drive for the magnetic system is The system can be omitted, and the magnetic field applied to the magneto-optical recording layer 47 can be kept constant.

Furthermore, when recording on the double-sided medium 43 as described above, since the double-sided medium 43 is provided with the high magnetic permeability layer 45,
The magnetic flux from the magnetic heads 19, 29 constitutes a magnetic closed loop, for example as shown by the broken line in FIG. Therefore, it is preferable that during recording, the magnetic flux 1 2 applied to the magneto-optical recording N47 of the double-sided medium 43 can be effectively converged and the perpendicular magnetic field efficiency can be increased.

Further, according to the above embodiment, it is possible to perform various recording and reproduction operations on the double-sided magneto-optical recording medium. For example, the first and second optical systems 1.21 and the magnetic head 29.
19 at the same time, it is possible to simultaneously record on the upper surface A side and the lower surface B side of the double-sided medium 43.
By using the optical system 1.21 and the second optical system 1.21 at the same time, simultaneous reproduction becomes possible. This makes it possible to increase the capacity and record and reproduce information signals at higher speeds.

Furthermore, it is possible to first perform recording or reproduction on one side of the double-sided medium 43, and then perform recording or reproduction on the other side. This allows recording and reproduction of twice the capacity compared to a single-sided magneto-optical recording medium.

Next, the case where recording and reproduction are performed on the single-sided medium 50 will be described.

As shown in FIG. 2, the single-sided medium 50 is arranged as described above so that its translucent cover 51 side faces the first optical system 1 side, and its protective cover 56 side faces the second optical system 22 side. It is mounted and rotated in the same manner as the double-sided media 43.

In this case, the first optical glass plate 28 is removed from between the first objective lens 2 and the transparent cover 51.

Then, the first optical system 1 focuses the laser beam on the recording magnetic layer 53, and the magnetic navel I" l 9 provided on the second optical glass 18 on the second optical system 22 side
As a result, a magnetic field is applied to the recording magnetic layer 53 from the protective cover 56 side of the single-sided medium 50. Then, the first optical system and the second optical system
The optical system is driven and displaced in synchronization with the T direction and the F direction. The above point is different from the case of the double-sided medium 43, and recording is otherwise performed in the same manner.

The single-sided medium 50 is reproduced by the first optical system 1 in the same way as the double-sided medium 43 (however, the first optical glass plate 2
8 has been removed).

In addition, in the above-mentioned first objective lens 2 and second pair 3 4 objective lens 22, their NAs are both 0.
It can be set to a value larger than 50 to 0.53, for example around 0.60, which narrows down the laser beam and focuses it on the recording layer, allowing for higher density recording and larger capacity than before. can be achieved. In this case, reproduction of a conventional optical recording medium recorded with a conventional NA objective is also possible with a larger NA objective as described above.

Next, when the double-sided medium 43 or the single-sided medium 50 is loaded into the magneto-optical recording/reproducing apparatus shown in FIGS. 1 and 2, it is detected which medium it is, and the first optical glass plate 28 is A specific example of an automatic mechanism for automatically feeding between and removing from the objective lens 2 of No. 1 and the recording medium will be described with reference to FIGS. 4A and 4B.

The automatic mechanism shown in FIG. 4A includes a first phantom lens 2 and a drive head 70 driven along a pair of guide shafts 73a and 173b. The first optical glass plate 28 described above
, are each provided with a morph 78 for rotating a pair of rotating arms 1.75a, 75b via a rotating shaft 74. For example, the double-sided medium 43 is accommodated in the disk car 1 to the printer 2. This disk cartridge 6
2 has a long window hole 63 in its corner, and this long window hole 6
A portion occupying approximately half of 3 is closed by a closing piece 64.

The automatic mechanism is provided with a medium detection means consisting of a light emitting element 65 and a pair of light receiving elements 66a and 66b at a position corresponding to the long window hole 63 of the disk cartridge 62 when it is installed in a predetermined position.

The operation of the automatic mechanism described above will be explained.

When the disk cartridge 62 containing the double-sided medium 43 is installed in a predetermined position, light from the light emitting element 65 is emitted from the fourth
As shown in Figure B, the light enters the light emitting element 66b and a predetermined signal is sent to a drive mechanism (not shown) of the drive head 70.

Note that at this time, the light from the light emitting element 65 is transmitted to the light receiving element 66.
The blocking piece 64 prevents the light from entering a. In addition, the first optical glass plate 28 has bins 77a and 77b provided on both sides of the first optical glass plate 28 in holes 76a and 76b provided in the rotating arms 75a and 75b, respectively. They are in the fitted state and are in the lifted position shown by the solid line of No. 4 Bjl (in FIG. 4A, for convenience, the bin 77a
, 77b and the holes 76a, 76b are shown not to be fitted into each other. ).

Next, the drive head 70 is moved along the guide shafts 73a and 73b in the direction of the arrow in FIG. 4B to the position indicated by the dashed line in FIG. 4B by the drive mechanism (not shown) to which the predetermined signal is sent. .

Next, the first optical glass plate 28 is lowered from the above-mentioned lifted position in the direction of arrow M in FIG. 4B while being rotated by the motor 78 about the rotation shaft 74 together with the rotation arms 75a and 75b.

Then, at the position indicated by the dashed line in FIG. 4B, the first
The optical glass plate 28 is positioned and driven by fitting a pair of holes 79a, 79b provided in the optical glass plate 28 into a pair of positioning pins 72a, 72b provided in the drive head 70. It is placed on the upper surface 70a of the head 70. As a result, the center of the coil pattern 27 formed on the first optical glass plate 28 and the center of the first objective lens 2 are aligned, and the driving head 70 and the first optical glass plate 28 are aligned. Become one.

Next, the rotating arms 75a and 75b are moved by a predetermined amount in the N' force direction and the N direction shown in FIG. The mating with each other is released.

Next, the first optical glass plate 28, which has been positioned and placed on the driving head 70 as described above and has become free from the rotating arms 75a and 75b, moves along with the driving head 70 in the direction of arrow L' in FIG. 4B. A drive mechanism (not shown) moves the device to a predetermined position for recording or reproducing, which is indicated by a two-dot chain line in FIG. 4B.

As described above, magneto-optical recording and reproducing 7 of this embodiment 8 The apparatus can be automatically placed in the configuration shown in FIG.

Further, when a disk cartridge containing the single-sided medium 50 described above is installed in this magneto-optical recording/reproducing apparatus, the position of the closing piece 64 in the cartridge as shown in FIG. is the light receiving element 6
6a (as shown by the broken line in FIG. 4B), and when this light is roughly divided into the light receiving element 66a, a predetermined signal is sent to a drive mechanism (not shown). The first optical glass plate 28 can then be removed from the drive head 70 by the automatic mechanism described above in an operation opposite to that described above. Therefore, the arrangement shown in FIG. 2 can be automatically achieved.

As explained above, the magneto-optical recording and reproducing apparatus of this embodiment uses the conventional transparent cover 5 having a thickness (for example, 1.2 mm).
1 and the double-sided medium 43 each having a thinner transparent cover, recording and reproduction are possible no matter which medium is attached.

It goes without saying that the double-sided medium 43 may be a medium having a structure similar to that shown in FIG. 1 but having a thinner light-transmitting cover, magneto-optical recording layer, etc. on one side.

Further, although this embodiment uses a magneto-optical recording medium, the present invention is not limited to this, and the recording medium may be any optical recording medium (for example, a read-only optical recording medium). It is clear that a write-once optical recording medium may also be used.

〔Effect of the invention〕

According to the optical recording/reproducing apparatus of the present invention, recording and/or reproduction can be performed on any of the optical recording media whose transparent covers have different thicknesses. This allows for compatibility between optical recording media with thinner translucent covers and thicker optical recording media, such as those with conventional translucent covers, as needed. Above all, it is extremely convenient.

[Brief explanation of drawings]

9 0 Figures 1 to 4B show an embodiment of an optical recording/reproducing apparatus according to the present invention, and Figure 1 shows an example of a magneto-optical recording/reproducing apparatus using a double-sided magneto-optical recording medium as an optical recording medium. 2 is a cross-sectional view of the case where a conventional single-sided magneto-optical recording medium is used in the magneto-optical recording and reproducing apparatus shown in FIG. 1, and FIG. FIG. 4A is a plan view showing an example of a coil pattern formed on an optical glass plate to construct a coil pattern, and FIG.
Figure 4B is a perspective view showing a specific example of an automatic mechanism for automatically adding or removing an optical glass plate for aberration compensation between an objective lens and a magneto-optical recording medium, and Figure 4B is similar to Figure 4A. FIG. 3 is a side view of the automatic mechanism shown. FIG. 5 is a schematic cross-sectional view of a conventional magneto-optical recording/reproducing device. In addition, in the symbols used in the drawings, 1--1-------First optical system (optical system) 2--
-1---First objective lens (objective lens) 28---
--11--First optical glass plate (transparent compensator) Double-sided magneto-optical recording medium (second optical recording medium) Magneto-optical recording layer (recording layer) 48.49-=Adhesive layer, transparent Optical protection plate (transparent cover) Single-sided magneto-optical recording medium (first optical recording medium) Transparent cover recording magnetic layer (recording layer) Thickness of transparent cover 51 Adhesive layer 48 and translucency The sum of the thicknesses of the first optical glass plate 28 and the thickness of the first optical glass plate 28 is 7 3 0 3 .

Claims (1)

[Claims] A recording layer that is irradiated with a laser beam for recording and/or reproduction, and a translucent cover that is provided to cover the recording layer and that allows the laser beam to pass through. In the first and second optical recording media, the first and second optical recording media are
The thickness of the light-transmitting cover of the optical recording medium is thicker than the light-transmitting cover of the second optical recording medium, and the laser beam is focused on the recording layer through the light-transmitting cover. and an optical system having an objective lens configured to be capable of recording and/or reproducing the first optical recording medium; and an optical system configured to perform recording and/or reproducing the second optical recording medium. An optical recording and reproducing apparatus, comprising: a light-transmitting compensating plate added between the objective lens and the second optical recording medium to compensate for aberrations in the objective lens.