KR19990018747A - Magneto-optical recorder - Google Patents

Abstract

Disclosed is a magneto-optical recording and reproducing apparatus whose structure is improved to increase the optical numerical aperture and reduce the access time.

The disclosed apparatus includes a fixed optical system for generating and irradiating light, a movable unit rotatably disposed with respect to the recording medium so that light provided from the fixed optical system is formed at a predetermined position of the recording medium, and both ends of the fixed optical system and the movable unit, respectively. A movable member having a base and a pair of first and second swing arms which are installed to be reciprocally rotatable on the base and opposed to each other with a recording medium interposed therebetween. And a first slider having magnetic drive means for driving the swing member, an end of the first swing arm provided to be in contact with the recording medium, and having a first through hole into which the end of the optical fiber is fitted. A focusing means for focusing the emitted light, a second slider installed at an end of the second swarm to face the first slider, and a second slider mounted in the second slider. For example, a polarizing plate for selectively transmitting according to the polarization direction of the incident light, a first photodetector for receiving and photoelectrically converting light transmitted through the polarizing plate, and a magnetic head mounted on the second slider to record information on the recording medium, It is characterized by.

Description

Magneto-optical recorder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording and reproducing apparatus, and more particularly, to a magneto-optical recording and reproducing apparatus having an improved structure to increase the optical numerical aperture and reduce the access time.

Generally, a magneto-optical recording and reproducing apparatus records and / or reproduces information on a recording medium in a non-contact manner using light.

1 is a schematic diagram showing an optical arrangement of a conventional magneto-optical recording and reproducing apparatus.

As shown in the drawing, a conventional magneto-optical recording and reproducing apparatus includes a light source 3 for generating and emitting light, a first beam splitter 7 for converting a traveling path of the light irradiated from the light source 3, and a recording medium ( An objective lens 9 for focusing incident light to form a light spot at 1), reflected light from the recording medium 1, and incident light through the objective lens 9 and the first beam splitter 7; And a photodetector configured to detect information signals and error signals. In addition, a magnetic head 30 for recording information on the recording medium 1 is further provided. Here, a collimating lens 5 is installed on the optical path between the light source 3 and the first beam splitter 7 to convert the divergent light emitted from the light source 3 into parallel light.

The photodetector includes a first photodetector 17 for detecting an information signal and a second photodetector 21 including four split plates independently photoelectrically converted to detect a focus error signal and a track error signal. The light incident from the first beam splitter 7 is branched by the second beam splitter 13 to the first and second photodetectors 17 and 21 at a predetermined light quantity ratio. Here, a first light receiving lens 15 for converging incident light is disposed between the second beam splitter 13 and the first light detector 17, and the second beam splitter 13 and the second light detector ( Between 21), a cylindrical lens 19 for generating convergence and astigmatism of incident light is disposed.

As described above, the configured magneto-optical recording and reproducing apparatus amplifies the track error signal and the focus error signal detected by the second photodetector 21 to correct the error signal by controlling the actuator 11 of the objective lens 9. The objective lens 9 is driven in the direction.

As described above, in the case of using the configured magneto-optical recording and reproducing apparatus, the minimum diameter of the recording mark formed on the recording medium 1 is equal to the numerical aperture of the objective lens 9 and the wavelength of the light source 3, as shown in Equation 1 below. Is determined by

Therefore, when the wavelength of the light source 3 is 650 nm and the numerical aperture of the objective lens 9 is 0.6, it can be seen that the diameter of the recording mark is limited to 650 nm. Therefore, there is a problem that cannot be employed in a high density recording medium.

In addition, since information is recorded / reproduced while being reciprocated in the radial direction of the recording medium 1 mounted on a carriage (not shown), the time required for finding the position of the recording medium 1 by the load applied to the carriage is called access. The disadvantage is that the time is as long as 100ms.

Accordingly, the present invention has been made in view of the above-described points, and improves the end of the optical fiber to a near-field probe structure instead of the objective lens, thereby reducing the optical numerical aperture and allowing only a part of the optical fiber to slide in contact with the recording medium. It is an object of the present invention to provide a magneto-optical recording and reproducing apparatus which can reduce the number of times.

1 is a schematic diagram showing an optical arrangement of a conventional magneto-optical recording and reproducing apparatus.

2 is a view showing an optical configuration of a magneto-optical recording and reproducing apparatus according to an embodiment of the present invention.

3 is a schematic perspective view showing the movable unit of FIG.

4 is a partial cross-sectional view showing the interior of the first and second sliders.

* Explanation of symbols for main parts of the drawings

100: fixed optical system 110: light source

120: collimating lens 130: optical path converting means

140: coupling lens 150: convergence lens

160: second photodetector 200: optical fiber

211: core 213: clad

215: focusing means 300: movable unit

310: swing member 311: first swing arm

313: second swing arm 320: base

321: shaft 330: magnetic drive means

331, 333: yoke member 341: magnet member

343: coil member 350: first slider

351: through hole 353: adhesive

360: second slider 370: polarizer

380: first photodetector 390: magnetic head

In order to achieve the above object, the present invention is fixedly arranged, and fixed optical system for generating and irradiating light, and rotatably disposed with respect to the recording medium so that the light provided from the fixed optical system is formed at a predetermined position of the recording medium. A magneto-optical recording and reproducing apparatus comprising a movable unit, and an optical fiber which transmits light by connecting both ends to the fixed optical system and the movable unit, respectively, wherein the movable unit is provided to the base and the base so as to be reciprocally rotated. A swing member having a pair of first and second swing arms opposed to each other with the recording medium interposed therebetween, magnetic driving means for driving the swing member, and the first swing arm to be in contact with the recording medium. A first slider installed at an end of the optical fiber and having a first through hole into which the end of the optical fiber is fitted; A focusing means for concentrating the emitted light, a second slider provided at an end of the second swarm to face the first slider, a polarizing plate installed in the second slider and selectively transmitting in accordance with the polarization direction of the incident light; And a first photodetector for receiving and photoelectrically converting light transmitted through the polarizing plate, and a magnetic head installed in the second slider to record information on the recording medium.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing an optical configuration of the magneto-optical recording and reproducing apparatus according to the embodiment of the present invention, FIG. 3 is a schematic perspective view showing the movable unit 300 of FIG. 2, and FIG. 4 is a first and second sliders. It is a partial sectional view of the inside of the.

As shown, the magneto-optical recording and reproducing apparatus according to the present invention is disposed rotatably with respect to the fixed optical system 100 and the recording medium 40 so that the light provided from the fixed optical system 100 is transmitted to the recording medium 40. It comprises a movable unit 300 to be formed at a predetermined position of the, and the optical fiber 200 to which both ends are respectively connected to the fixed optical system 100 and the movable unit 300 to transmit light.

The fixed optical system 100 is fixedly installed on a main body (not shown), and generates and irradiates light required to record / reproduce information on the recording medium 40. The optical fiber 200 is composed of a core 211 and a clad 213 having a refractive index different from that of the core 211. The clad 213 surrounds the core 211, and incident light is guided through the core 211. Here, the optical fiber 200 is preferably a polarization maintaining optical fiber that does not change the polarization direction when transmitting light in consideration of the polarization characteristics described below.

The movable unit 300 causes the light irradiated from the fixed optical system 100 to be guided through the optical fiber 200 at a predetermined position of the recording medium 40. To this end, the movable unit 300 includes a base 320 fixed to the main body (not shown), a swing member 310 installed to reciprocally rotate to the base 320, and the swing member 310 to drive the swing member 310. A first slider 350 having magnetic driving means 330, an end of the optical fiber 200, and one surface 350a contacting the recording surface of the recording medium 40, and a recording medium in the optical fiber 200. A focusing means 215 for focusing the light emitted toward 40, a second slider 360 in contact with the other surface of the recording medium 40, and a polarizer 370 provided in the second slider 360. And a first photodetector 380 and a magnetic head 390.

The fixed optical system 100 is disposed between a light source 110 for generating and irradiating light and a coupling lens 140 disposed between the light source 110 and an input terminal of the optical fiber 200 to focus incident light onto the optical fiber 200. It is configured to include). The light source 110 employs a conventional semiconductor laser that can be easily downsized.

Here, the collimating lens 120 is disposed on the optical path between the light source 110 and the coupling lens 140 to focus the divergent light emitted from the light source 110 to emit parallel light. It is desirable to.

In addition, the fixed optical system 100 is disposed on an optical path between the light source 110 and the coupling lens 140, the optical path conversion means 130 for converting the traveling path of light, and the recording medium 40 It is preferable to further include a second photodetector 160 which is incident on the side and is capable of receiving the light incident through the optical fiber 200 and the optical path converting means 130. As such, when the second photodetector 160 is further provided, the information signal formed on the recording medium 40 is detected from the light reflected by the recording medium 40 and received by the second photodetector 160. do.

Here, a beam splitter may be used to transmit part of the incident light to the optical path converting means 130 and reflect the rest of the incident light to change the advancing path of the incident light. In this case, the beam splitter and the second photodetector 160 include a converging lens 150 that focuses the light directed to the second photodetector 160 through the beam splitter to the second photodetector 160. It is preferable to provide in between.

In addition, a hologram element (not shown) may be employed to transmit light incident from one surface to the light path converting means 130 in a straight line, and diffracted transmission of light incident from the other surface in order to change the traveling path of the light. .

The magnetic driving means 330 is installed across the base 320 and the swing member 310 to provide a reciprocating rotational driving force of the swing member 310. To this end, the magnetic driving means 330 is installed on the coil member 343 and the base 320 coupled to one side of the swing member 310, respectively, on the upper and lower outer sides of the coil member 343. The yoke members 331 and 332 positioned to be coupled to the yoke member 331 are installed to face the yoke members 331 and 332 with the coil members 343 interposed therebetween. It is configured to include a magnet member 341 disposed inside. Therefore, the swing member 310 is operated by mutual electromagnetic force with the magnet member 341 by adjusting the direction and intensity of the current applied to the coil member 343.

The swing member 310 has a coupling hole (310a), it is possible to reciprocate rotation with respect to the base 320 by a shaft 321 through the coupling hole (310a) both ends coupled to the base 320 Is installed. The swing member 310 has a pair of first and second swing arms 311 and 313 provided to face each other with the recording medium 40 therebetween. Here, the first swing arm 311 is disposed to face the light incident surface 30a of the recording medium 40, and the second swing arm 313 is disposed to face the rear surface 30b of the recording medium 40. At the end of the first swing arm 311, a first slider 350 installed to be in contact with the recording medium 40 is coupled.

To this end, the first swing arm 311 is preferably an elastic plate elastically supported so that the first slider 350 receives a force in a direction in which the first slider 350 is in contact with the recording medium 40.

The first slider 350 has a first through hole 351 into which the light output end of the optical fiber 200 is fitted, and the first swing with one surface 350a in contact with the recording medium 40. Rotated by the arm 311, the outgoing light is guided to the predetermined track of the recording medium 40.

The focusing means 215 is focused in the first through hole 351 to focus light emitted from the optical fiber 200 toward the recording medium 40. Here, the focusing means 215 is a reflection member having a reflective surface therein in a hollow truncated cone shape such that the diameter of the exit end from which light is emitted is smaller than the incident end from which light is incident, as shown in FIG. 4. Is preferably. The reflective member is installed in the first through hole 351 by an adhesive 353 or the like so as to be fixed while the position of the reflective member is determined with respect to the first slider 350.

Therefore, the light generated by the fixed optical system 100 and guided through the optical fiber 200 is focused by the converging means 215, for example, through a hollow truncated cone-shaped reflective member having a reflective surface therein. Focused on medium 40. In this way, when the light is focused by the focusing means 215, the diameter of the light that forms on the recording medium 40 can be reduced by approximately one quarter or more compared with the case where an objective lens with a numerical aperture of 0.6 is employed.

The second slider 360 is disposed at the end of the second swing arm 313 to face the first slider 350. The first photodetector 380 is formed in the second slider 360, passes through the converging means 215, forms the recording medium 40, and receives the transmitted light so that the light spot is normally tracked. Determine whether to follow. To this end, the first photodetector 380 has a first detection region 380a and a second detection region 380b for photoelectric conversion of incident light independently, and the first detection region 380a and the second detection region ( Preferably, the boundary line 380b is arranged in a direction parallel to the track direction of the recording medium 40.

The magnetic head 390 is coupled to the second slider 360 to record information on the recording medium 40.

There are two ways of recording information on the recording medium 40. First, while performing a tracking servo using the first and / or second photodetectors 380 and 160 in a state where the light source 110 is continuously oscillated, the magnetic direction of the magnetic head 390 is modulated. Magneto-optical recording can be performed. This method is called a magnetic field modulation method, and since it is widely known, its detailed description is omitted. Second, after setting the magnetization direction of the magnetic head 390 in a direction different from the initial magnetization direction of the recording medium 40, the light source 110 is modulated to heat the laser beam irradiation site above the Curie temperature. Cooling can be used to record. This method is called light modulation.

The polarizer 370 is installed in the second slider 360 to be disposed between the first photodetector 380 and the recording medium 40. The polarizer 370 is used to reproduce information recorded on the recording medium 30. That is, when the information is reproduced, if the polarization direction of the laser beam focused on the recording medium 40 due to the magneto-optical effect is Θ in the unrecorded portion, the recorded portion is rotated by -Θ. Therefore, since the light in the polarization direction corresponding to the area where the information signal is recorded or the light in the polarization direction corresponding to the area opposite to the light is transmitted through the polarizing plate 370 and is incident on the first photodetector 380, the amount of transmitted light is different. The information signal can be read.

The operation of the magneto-optical recording and reproducing apparatus of the present invention will be described below with reference to the drawings.

The light irradiated from the light source 110 is focused on one end of the optical fiber 200 by the coupling lens 140. The focused light is guided through the optical fiber 200, and then focused on a predetermined track of the recording medium 40 by the focusing means 215, for example, a reflective member. Here, the position of the light bound to the recording medium is determined according to the rotational position of the swing member 310 by the magnetic driving means 330. Thus, when the recordable recording medium 40 is employed, the information can be recorded by the light focused on the recording medium 40.

As such, a part of the focused light is transmitted through the recording medium 40 to form the first photodetector 360, and is received in each of the first photodetection region 360a and the second photodetection region 360b. The track error signal is detected by the differential of the photoelectrically converted light, and the magnetic driving means 330 is driven to correct the track error. In addition, during reproduction, the first photodetector 360 may detect an information signal by determining a recording mark (not shown) formed on the track from the detected signal.

The recording of the information signal is performed using the above-described magnetic field modulation method or light modulation method.

In addition, when the second photodetector 160 is further provided, the light reflected from the recording medium 40 is guided to the fixed optical system 100 through the focusing means 215 and the optical fiber 200. The light path converting means 130 is reflected by the beam splitter and is incident on the second light detector 160. From the incident light, a recording mark formed on the track is discriminated to detect an information signal.

In this manner, in the case where the configured magneto-optical recording and reproducing apparatus is adopted, the diameter of the light spot focused by the focusing means can be approximately the same size as the exit opening of the focusing means 215, that is, the reflecting member. Therefore, when the diameter of the light spot is 150 nm, the recording density is 4.4 gigabits (square centimeters). In the case where an optical disc having a diameter of 12 cm is used as the recording medium 40, recording / reproducing of information is possible even when a high density recording medium 40 having a capacity of about 500 gigabytes or 62 gigabytes is employed.

In addition, only a part of the swing member 310, the first slider 350, the first photodetector 360, and the optical fiber 200 slides along the track of the recording medium 40, so that the load applied to the movable unit 300. Can be greatly reduced. Therefore, the access time, which is the time taken to move between tracks, can be greatly reduced to 10 msec or less.

Claims (9)

A fixed optical system fixedly arranged to generate and irradiate light, a movable unit arranged to be rotatable with respect to the recording medium so that the light provided from the fixed optical system is formed at a predetermined position on the recording medium, and to the fixed optical system and the movable unit. A magneto-optical recording and reproducing apparatus comprising an optical fiber for transmitting light at both ends thereof, wherein the movable unit is provided so as to reciprocally rotate on a base and to face each other with the recording medium therebetween. A swing member having a pair of installed first and second swing arms, magnetic driving means for driving the swing member, and an end of the first swing arm to be in contact with the recording medium, and an end of the optical fiber A first slider having a first through hole to be fitted, focusing means for focusing light emitted from the optical fiber toward the recording medium, and A second slider disposed at an end of the second swarm to face the first slider, a polarizer installed in the second slider to selectively transmit according to the polarization direction of the incident light, and a light transmitted through the polarizer to receive photoelectricity And a magnetic head mounted on the second slider to record information on the recording medium. According to claim 1, wherein the focusing means is inserted into the first through groove, the reflecting surface therein in the shape of a hollow truncated conical shape so that the diameter of the exit end from which light is emitted compared to the incident end to which light is incident. And a magneto-optical recording and reproducing apparatus, characterized by having a reflecting member. The recording medium of claim 1, wherein the first photodetector has a first detection region and a second detection region for photoelectric conversion of incident light independently, and a boundary line between the first detection region and the second detection region is a track of the recording medium. And a magneto-optical recording and reproducing apparatus, arranged in a direction parallel to the direction. The method of claim 1, wherein the magnetic drive means, the coil member is coupled to one side of the swing member, the yoke member is installed on the base, the upper and lower outer portions of the coil member, and the yoke member A magnet member disposed in the coil member so as to face the yoke member with the coil member interposed therebetween by the direction and the intensity of the current applied to the coil member and the mutual electromagnetic force of the magnet member. Magneto-optical recording and reproducing apparatus, characterized in that the swing member can be moved. The magneto-optical recording and reproducing apparatus according to claim 1, wherein the first swing arm is an elastic plate which elastically supports the first slider so that the first slider receives a force in a direction in which the first slider contacts the recording medium. The coupling lens according to any one of claims 1 to 5, wherein the fixed optical system comprises a light source for generating and irradiating light, and a coupling lens arranged between the light source and an input end of the optical fiber to focus incident light on an input end of the optical fiber. Magneto-optical recording and reproducing apparatus comprising a. 7. The optical system of claim 6, wherein the fixed optical system comprises: optical path converting means disposed on an optical path between the light source and the coupling lens to convert a traveling path of light, and incident from the recording medium; And a second photodetector configured to receive light incident through the means. 8. The magneto-optical recording and reproducing apparatus according to claim 7, wherein the optical path converting means is a beam splitter which transmits a part of incident light and reflects the rest of the incident light to change a traveling path of the incident light. The collimating lens according to any one of claims 6 to 8, further comprising a collimating lens disposed on an optical path between the light source and the coupling lens to focus divergent light radiated from the light source so that parallel light is emitted. Magneto-optical recording and reproducing apparatus characterized in that.