JPH1116198A - Optical head and information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a slider mounting an optical system small in the increase of mass by making the end surface of an optical fiber appear on the surface opposite to an information recording medium of the slider fitting the optical fiber and forming a thin film consisting of an opaque material on this end surface and providing a pin hole in a core part of the optical fiber of this thin film. SOLUTION: A slider 1 is relatively moved with an information recording medium 2 at a relative speed (v) and is supported by an arm 6 to be brought into contact with the information recording medium 2 through a contact pad 8 to be moved relatively while being rubbed. The slider 1 is provided with a hole for inserting an optical fiber from the upper part to the lower part so as to coincide with the position of the contact pad 8 and the lower part side end surface is provided with a pin hole in a position to coincide with the above hole. Moreover, the optical fiber 12 consisting of a core 3, a clad 4 and a coat 5 is stuck to this hole with an adhesive 7. Then, the end part of the core 3 and the clad 4 of the optical fiber 12 are processed in a projecting shape to constitute the contact pad 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical head for recording and reproducing on a recording medium using light, and an information recording and reproducing apparatus.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 3-171434 discloses a light source, a recording medium, a fine pinhole, a light receiving optical system, and control means for controlling a distance and a position between the fine pinhole and the recording medium. There is disclosed a memory recording device that includes a light receiving optical system that receives light from the light source through the fine pinhole and the recording medium.

[0003]

In the prior art, the flying slider is provided with a laser light source and a lens. When a laser light source and a lens are mounted on the slider, the mass of the slider increases. Then, there is a problem that the follow-up characteristic to the recording medium is deteriorated, and the construction of the apparatus becomes impossible in practice.

An object of the present invention is to propose a configuration of a slider on which an optical system having a configuration with a small increase in mass is mounted.

[0005]

SUMMARY OF THE INVENTION A slider which makes relative movement while being in contact with an information recording medium or at a constant interval, and a thin film made of an opaque material on a surface of the slider facing the information recording medium. Is formed, a pinhole is provided in a part thereof, and one end of an optical fiber for irradiating light to the recording medium, which is attached so that the pinhole coincides with the core portion, or receives light from the recording medium. One end of an optical fiber for receiving light is provided, and the other end of the optical fiber is attached to a light emitting / receiving section provided on an actuator section of an arm supporting the slider.

[0006]

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

FIG. 1 is a sectional view of a slider on which the optical head of the present invention is mounted.

In FIG. 1, a slider 1 moves relative to an information recording medium 2 at a relative speed v. The slider 1 is supported by an arm 6, contacts the information recording medium 2 at a contact pad 8, and moves relatively while rubbing.

The slider 1 is provided with a hole into which an optical fiber is inserted from the upper part to the lower part so as to coincide with the position of the contact pad 8, and a pinhole is formed on the lower end face at a position corresponding to the hole. Is provided. An optical fiber 12 composed of a core 3, a clad 4, and a coating 5 is bonded to the hole with an adhesive 7.
The ends of the core 3 and the clad 4 of the optical fiber 12 are processed into a convex shape to form a contact pad 8.

[0010] Although not shown in FIG.
Light from a light source provided in a place different from the slider 1 is incident on 2. The light incident on the optical fiber 12 is applied to a pinhole 14 provided in the contact pad 8.
(To be described later), and is irradiated on the information recording medium 2. The light transmitted from the information recording medium 2 out of the light emitted from the slider 1 is detected by the photodetector 9.

The photodetector 9 is an ordinary photodiode,
Avalanche photodiodes and photomultipliers can be used to convert transmitted light into electrical signals.

The information recording medium 2 comprises a transparent substrate 11 and a recording film 10. As a material of the transparent substrate 11, quartz, polycarbonate, or the like can be used. The recording film 10 is a Ge-Sb-Te-based phase change recording film used in a normal phase change type optical disk device. The recording film 10 includes
A certain mark is formed by removing a part of the recording film 10 or causing a phase change in the etching process, and information is recorded by the mark. For example, when a part of the recording film 10 has been removed, the light transmittance of the removed part becomes larger than that of the other part. Therefore, the recording film 10 is irradiated with light,
The information recorded on the recording film 10 can be read by detecting the intensity of the transmitted light. Although not shown in FIG. 1, a C (carbon) film having a thickness of several nm is further formed on the surface of the recording film 10, and a polymer lubricant is also applied thereon with a thickness of several nm.
It has been applied. The recording film 10 is formed by the C film and the lubricant.
Has increased wear resistance.

FIG. 2 is an enlarged view of a contact pad 8 portion.

The end face of the clad 4 is formed in a convex shape, and the core 3 is recessed. The light shielding film 15 is formed thereon, and the core 3 of the optical fiber 12 of the light shielding film 15 is formed.
Is provided with a pinhole 14. The information recording medium 2 is irradiated with light propagating through the core 3 through the pinhole 14.

FIG. 3 shows a manufacturing process of the slider of the present invention.

The manufacturing process of the slider on which the optical head of the present invention is mounted will be described with reference to FIG. First, FIG. 3 (a)
As shown in (1), a hole for fixing the optical fiber 12 is made in the substrate 13. As will be described later, since a quartz-based optical fiber is used as the optical fiber 12, the substrate 13 is a quartz substrate. The reason why the substrate 13 is a quartz substrate will also be described later. In a normal optical fiber, the diameter of the cladding 4 is 12
5 μm, diameter of coating 6 250 μm. As described below,
The bonding of the optical fiber 12 to the substrate 13 is performed at the covering portion. Therefore, the diameter b of the hole is set to 300 μm, which is slightly larger than the diameter of the coating 6 than 250 μm.

Next, the optical fiber 12 is inserted into the hole manufactured in FIG. At this time, FIG.
As shown in (b), the length q of the portion of the optical fiber 12 from which the coating 6 has been peeled is made shorter than the thickness r of the substrate 13, and bonding is performed from outside the coating 6. In general, a silica-based optical fiber is very likely to break when the cladding is stripped off after the resin coating is removed. Also in this case, q in FIG.
If the bonding is performed only at the part of the clad 5,
The portion of the clad 5 is broken. Therefore, as shown in FIG. Any kind of adhesive may be used, but it is preferable to use an adhesive which becomes a ceramic after curing. In addition, it is necessary to make s in FIG. 3B shorter than q so that the coating 6 does not protrude from the lower surface of the substrate 13 in FIG. 3B.

After the adhesive 7 is cured, as shown in FIG. 3C, the lower surface of the substrate 13 and the optical fiber 12 shown in FIG.
Is polished so that the end faces are the same. At this time, if the hardness of the substrate 13 and that of the optical fiber 12 are different, even if the lower surface of the substrate 13 and the end surface of the optical fiber 12 in FIG. Therefore, in order to make the hardness of the optical fiber 12 and that of the substrate 13 uniform, when the optical fiber 12 is a quartz optical fiber, the substrate 13 is a quartz substrate. The same applies to the adhesive 7, and it is desirable that the hardness of the cured adhesive 7 matches the substrate 13 as much as possible. Therefore, it is desirable that the adhesive be a ceramic after being cured.

After polishing as shown in FIG. 3C, FIG.
As shown in (d), the end faces of the substrate 13 and the optical fiber 12 are machined to form the contact pads 8. The height H of the contact pad 8 is generally set so that the posture of the slider 1 in FIG. 1 and the pressing force against the information recording medium 2 do not change due to the fluid force acting on portions other than the contact pad 8.
It needs to be larger than 10 μm. Typically 20-50
It may be set to μm. Contact pad width W and length L
May be set to 50 to 100 μm so that the frictional force does not become too large and the contact stress does not increase.

After forming the contact pads 8, the substrate 1
3 is cut to form the slider 1 as shown in FIG.

After being cut as shown in FIG. 3E, the contact pad 8 is subjected to etching as shown in FIG. In this processing, the optical fiber 12 is
A silica-based optical fiber doped with 23 mol% of GeO2 as a dopant in the core 3 and a solution obtained by mixing a 50% aqueous solution of HF, pure water and a 40% aqueous solution of NH4F in a ratio of 1: 1: 0.5 by volume as an etchant. The etching is performed at room temperature. The dent amount needs to be discussed later. In this example, since the contact pad 8 is in contact with the information recording medium 2, the amount of depression of the core 3 gives the distance h between the pinhole 14 and the information recording medium 2 in FIG.

After providing a recess in the core 3, a light-shielding film 15 is formed on the contact pad 8. The material and thickness of the light-shielding film 15 are determined in consideration of the fact that light incident on the optical fiber 12 can be shielded and the wear resistance when the slider 1 comes into contact with the information recording medium 2 for some reason. I do. For example, Cr can be used in consideration of both abrasion resistance and light shielding properties, and the thickness may be typically 100 to 200 nm.

Thereafter, as shown in FIG. 3 (g), a pinhole 14 is provided in the recess provided in the core 3. The processing of the pinhole 14 is performed by a focused ion beam (hereinafter, a focused ion beam,
sedIon Beam, abbreviated as FIB). In a typical FIB apparatus, a beam diameter of several tens nm can be obtained with an acceleration voltage of several tens kV, and a pinhole having a diameter of several tens nm can be provided. The light shielding film 9 is a Cr film, and the thickness is 100 to 2
When it is set to 00 nm, the beam irradiation time is typically 1 second or less to several seconds.

In the case of processing using the FIB, a normal FIB apparatus irradiates a sample to be processed while scanning the FIB, and takes an image of emitted secondary electrons (this image is called a Scan
ningIon Microscopy, acronym for SIM image). Using this SIM image, the FIB is aimed at a predetermined place to be processed. Here, since the core 3 is provided with a depression, the position of the core 3 can be accurately specified on the SIM image, and the pinhole 14 can be accurately provided in the portion of the core 3.

If there is no such mark, the position of the core 3 cannot be specified on the SIM image, and it is difficult to provide the pinhole 14 in the core 3. Since the light is confined in the core 3, the intensity of the light applied to the information recording medium 2 is reduced unless the pinhole 14 is provided accurately at the position of the core 3. For this reason, the pinhole 14 needs to be provided accurately at the position of the core 3. Depressing the core 3 has not only a mark for performing FIB processing but also another advantage. Since the portion of the pinhole 14 does not directly contact the information recording medium 2, the light shielding film 15
Even if it is peeled off somewhat, the pinhole 14 is not affected, and the performance of the pinhole 14 can be maintained. The slider 1 can be created by the above process.

With the above configuration, the slider 1
Thus, it is possible to realize an optical head slider capable of preventing an increase in the weight of the optical head and reading information recorded at high density.

FIG. 4 is a perspective view of an information recording / reproducing apparatus to which the optical head of the present invention is applied. The information recording medium 2 has a disk shape and is rotated by a spindle motor 22 fixed to a base 21. Due to this rotational movement, the slider 1 makes a relative movement. The positioning actuator 23 is also fixed to the base 21, and the arm 6 is fixed to the movable part. The positioning actuator 23 rotates around its axis, and moves the slider 1 attached to the tip of the arm 6 in the radial direction of the information recording medium 2. The structures of the slider 1 and the information recording medium 2 are the same as those of the slider 1 and the information recording medium 2 of FIG. The interface 24 fixed to the base 21 has a connector 25. The interface 24 receives power from the cable connected to the connector 25 to drive the apparatus, and also commands the apparatus to record and reproduce information and information to be recorded. Input and output of information to be reproduced.

When the interface 24 receives a command for recording or reproducing information from outside the apparatus, the interface 24 inputs the command to the system controller 26. The system controller 26 receiving this command supplies power to the spindle motor 22 to rotate the information recording medium 2. The slider 1 moves relative to the information recording medium 2 as described with reference to FIG. The system controller 26 further turns on the laser light source 27. The light emitted from the laser light source 27 enters the optical fiber 12 (not shown in FIG. 4) and irradiates the information recording medium 2 through the pinhole 14. The system controller 26 turns on the laser light source 27 and receives a signal from the photodetector 9 at the same time.

On the information recording medium 2, a row of marks on which information is recorded, called tracks, is provided concentrically. As will be described later, each track is formed with a mark for identifying the track and a mark for identifying a deviation from the track. Therefore, the system controller 26 can determine from the signal from the photodetector 9 which track the pinhole 14 on the information recording medium 2 is on and how much the pinhole 14 is off the track. The system controller 26 compares a position where information designated by an instruction from the outside of the apparatus is to be recorded or reproduced with an actual position of the pinhole 14 obtained from a signal from the photodetector 9. Based on the result of this comparison, the positioning actuator 23 is driven to position the pinhole 14 on a predetermined track on the information recording medium 2.

After the positioning is performed, if the command from outside the apparatus is to reproduce information, the system controller 2
6 causes the laser light source 27 to emit light at a constant intensity. This emission intensity is an intensity that does not destroy information recorded on the recording film 10. The information recording medium 2 has a recording mark formed by removing a part of the recording film 10 or changing the phase of the recording film 10, and is radiated from the laser light source 27 and passed through the pinhole 14. Information is reproduced by detecting the amount of transmitted light of the light applied to the recording film 10 by the photodetector 9. The information detected by the photodetector 9 is subjected to processing such as error correction by the system controller 26, and then output from the interface 24 to the outside of the apparatus.

When the command from the outside of the apparatus is to record information, the system controller 26 modulates the intensity of light emitted from the laser light source 27 in accordance with the information to be recorded. Information is recorded by changing the phase of the recording film 10.
The phase-change recording film is heated to a molten state and rapidly cooled to become an amorphous state, and gradually cooled to become crystalline.
When the recording film 10 is melted by irradiating light from the laser light source 27 through the pinhole 14 and the light emission intensity of the laser light source 27 is rapidly reduced, the recording film 10 is rapidly cooled and becomes amorphous, and gradually drops. And gradually becomes crystalline. Information is recorded by alternately arranging the crystalline and amorphous portions.

FIG. 5 is an enlarged view of the vicinity of the arm 6, and FIG.
The upper part is a plan view of the arm 6, and the lower part is a front view. The slider 1 is attached to a fixed portion 55, and the fixed portion 55
The intermediate holder 57 is attached to the arm 6 via the x support spring 54 and the intermediate holder 57 via the θy support spring 56. The fixing portion 55 rotates around the x-axis due to the torsional deformation of the θx support spring 54, and rotates around the y-axis due to the torsional deformation of the θy support spring 56. This rotation causes the slider 1 to follow the information recording medium 2.

The optical fiber 12 is fixed to a fixing portion 55 by a fixing jig 52 and to the arm 6 by a fixing jig 53. The optical fiber 12 forms a loop 51 at the fixing jig 52. One end of the loop 51 is fixed to the slider 1, and the other end is fixed to a fixing jig 52. Both the fixing jig 52 and the slider 1 are fixed to the fixing portion 55. Therefore, the optical fiber 12 is
Any reaction force when bent as described above acts on the fixing portion 55. Among the reaction forces, the reaction force acting on the slider 1 and the reaction force acting on the fixing jig 52 completely cancel each other according to the law of the action reaction. Therefore, the reaction force when the optical fiber 12 is bent like the loop 51 is
Does not substantially act on the fixing portion 55. This reaction force does not need to be considered when considering the operation of the fixing portion 55.

Since the optical fiber 12 is further fixed to the arm 6 by the fixing jig 53, the bending rigidity of the portion between the fixing jigs 52 and 53 of the optical fiber 12 is determined by the rotational movement of the fixing part 55 about the y axis. And the torsional stiffness affects the rotational movement about the x-axis. This effect increases the distance Lf between the fixing jigs 52 and 53 in FIG.
By lowering the rigidity between the fixing jigs 52 and 53, it is possible to reduce the rigidity to a practically acceptable level.

For example, the material of the θx support springs 54 and θy 56 is an iron-based material, the shear modulus is about 80 GPa, the spring lengths Lx and Ly are both 2 mm, and the diameters Dx and Dy are 200 μm. Since the optical fiber 12 is a silica-based optical fiber, the Young's modulus is about 70 GPa, the shear modulus is about 30 GPa, the interval Lf between the fixing jigs 52 and 53 is 20 mm, and the diameter of the optical fiber 12 is 250 μm. Assuming that the diameter of the information recording medium 2 is, for example, 2.5 inches, the radius is 31.75 mm and the arm 6
Must be longer than this, Lf = 2
0mm is a possible value.

Both the Young's modulus and the shear modulus of the resin used for the coating 5 of the optical fiber 12 are 1/10 to 1/100 that of quartz.
Ignoring the stiffness of the coating 5 (or
The thickness of the coating 5 is such that its rigidity is negligible compared to the portion of the cladding 4). Then, the torsional stiffness of the θx support springs 54 and 56 is about 12.6 mN · m / rad with two springs. The bending rigidity between the fixing jigs 52 and 53 of the optical fiber 12 is 0.672 mNm / rad, and the torsional rigidity is 0.575 mNm / rad.
In each case, the torsional stiffness of the θx support spring 54 and the θy support spring 56 is smaller by one order of magnitude or more, and does not cause any practical problem. Further, the frictional force between the optical fiber 12 and the arm 6 is also reduced by the fixed portion 5.
5 affects the operation of the optical fiber 1 as shown in FIG.
By floating the arm 2 from the arm 6, the influence of the frictional force can be eliminated.

The arm 6 is attached to a positioning actuator 23, and a laser light source 27 is attached to the base of the arm 6. The laser light source 27 includes a semiconductor laser 60, a coupling lens 59, and a fiber holder 58. Light emitted from the semiconductor laser 60 is condensed by the coupling lens 59 and coupled to the optical fiber 12. The fiber holder 58 fixes the end face of the optical fiber 12 to the focal point of the coupling lens 59.

Light emitted from the semiconductor laser 60 is incident on the optical fiber 12 and the pinhole 1 of the slider 1 is formed.
4, the information recording medium 2 is irradiated. The semiconductor laser 60 is connected to the system controller 26 via a cable 61, and blinks according to a command from the system controller 26. Since the semiconductor laser 60 and the coupling lens 59 are actually quite heavy components, they are brought outside the slider 1 as shown in FIG. 5, particularly near the rotation axis of the positioning actuator 23, rather than being mounted on the slider 1. .
Thus, by providing the main optical system near the rotation axis of the actuator 23 or on the base near the actuator, the actuator can be operated with a small driving force.

FIG. 6 is an enlarged view of the surface of the information recording medium 2.

In FIG. 6, white marks and black circular marks are arranged on a gray background. The gray part is the recording film 10
Is amorphous, a white portion indicates that the recording film 10 is removed therefrom, and a black portion indicates that the recording film 10 is crystalline. The light transmittance of the crystalline portion is lower than that of the amorphous portion, and the transmittance of the portion not having the recording film 10 is higher than that of the portion where the recording film 10 is provided.

In FIG. 6, six tracks 31 to 36 are indicated by dotted lines. Originally, the track is circular, but since a part of the track is enlarged, it looks like a straight line in FIG.

Each track is provided with a track identification mark 37. This mark is different for each track, and identifies the track on which the pinhole 14 is located. Each track is further provided with a wobble mark 38 and a wobble mark prediction mark 39.

The pinhole 14 is provided in the information recording medium 2
In FIG. 6, relative movement is performed from the bottom to the top. The wobble mark prediction mark 39 indicates that the wobble mark 38 comes after this. Therefore, the wobble mark prediction mark 3
Reference numeral 9 denotes a pattern which is not used except for the location immediately before the wobble mark 38. The wobble mark 38 is composed of two marks shifted left and right with respect to the track, and is a mark for detecting a shift between the pinhole 14 and the track.

For example, it is assumed that the pinhole 14 has passed near the track 36 along a solid line 41 near the track 36. The light detector 9 detects two light pulses when the pinhole 14 passes the wobble mark 38 after the light pulse when the pinhole 14 passes the wobble mark prediction mark 39.

When the trajectory of the pinhole 14 is shifted to the left from the track 36 as shown by the solid line 41, the first pulse of the two light pulses is strong, and the subsequent pulses are weak. The mark portion is a portion having a high light transmittance, and the wobble mark 3
This is because the first mark of No. 8 has a large overlap, and the subsequent marks have a small overlap.

If the track 36 has a pinhole 14
Is shifted to the right, the first light pulse is weakened and the second light pulse is strong.

When the trajectory of the pinhole 14 is exactly on the track 36, the two light pulses have the same intensity.

In the system controller 26, the two pulses immediately after the light pulse corresponding to the wobble mark prediction mark 39
By comparing the magnitudes of the individual light pulses, it is possible to determine to which and how much the trajectory of the pinhole 14 is shifted from the track. A signal indicating this deviation is called a track error signal.

In both the recording mark 40 and the identification mark 37 recorded by a command from the outside of the apparatus,
The pinhole 14 can obtain the largest signal (in this case, an optical pulse) when passing just above the track. In the reproduction of information, in order to reduce errors in the reproduced information, the larger the signal, the more desirable. For this purpose, the system controller 26 drives the positioning actuator 23 based on the track error signal, and positions the pinhole 14 just above a predetermined track. Also in the case of information recording, recording is performed by positioning on a track in consideration of the case of reproducing the recorded information.

In FIG. 6, an identification mark 37, a wobble mark 38, and a wobble mark prediction mark 39 are recorded on the recording film 1.
0 is formed, whereas the recording mark 4
0 is formed by a phase change. Compared with the transmittance of the amorphous portion, the transmittance of the identification mark 37, the wobble mark 38, and the wobble mark prediction mark 39 is higher, and the transmittance of the recording mark 40 is lower. Therefore, it can be identified from the transmitted light amount whether it is a mark indicating the position of the pinhole 14 or recorded information.

FIG. 7 is an explanatory diagram of the operation principle of the present invention.
It is also an enlarged view near the pinhole 14. In the first embodiment, light that has passed through the pinhole 14 is irradiated on the recording film 10 to record and reproduce information. In order to optically record and reproduce information, the size of the light spot needs to be smaller than or larger than the recording mark.
It is difficult to record and reproduce a recording mark much smaller than the light spot.

In an ordinary optical disk device, light is focused by a lens in order to form a light spot. In this case, it is theoretically difficult to obtain a spot smaller than the light wavelength. In a normal optical disk drive, the wavelength of the light source is approximately 600
800800 nm, and the size of the spot is also approximately this size. On the other hand, in the first embodiment of the present invention, the size of the light spot is a value obtained by adding the depth of light penetration into the light shielding film 9 to the size d of the pinhole 14.

As described above, even when processing is performed using a typical FIB apparatus, the diameter of the pinhole 14 can be several tens nm, and the depth of light penetration is typically several tens nm. Therefore, the size of the light spot is 100 nm or less. Therefore, it is possible to record and reproduce smaller recording marks than in the case of a normal optical disk device. From this fact, an information recording / reproducing apparatus having a higher recording density than a normal optical disk apparatus can be configured.

In FIG. 7, the pinhole 14 and the recording film 1
When the interval h of 0 is 0, the size D of the light spot on the recording film 10 becomes the size d of the pinhole 14 as described above.
And the depth of light seeping into the light-shielding film 9. However, when the distance h increases, the light spreads by diffraction, and the size D of the light spot increases. In order to consider the limit of the interval h, the recording film 10
A two-dimensional Fourier transform is performed on the above light amplitude. Then, in order to form a light spot of size D, the recording film 10
About the wave vector p above,

[0055]

(Equation 1)

The following spatial frequency components are required.

Here, since it is considered that a light spot sufficiently smaller than the wavelength of light is formed by using the pinhole 14, D <λ. Regarding the amplitude of the light passing through the pinhole 14, a component in which the absolute value of the in-plane spatial frequency of the recording film 10 is π / D will be considered. This component is hereinafter referred to as a. Since the amplitude of light on the recording film 10 satisfies the Helmholtz equation, the manner in which D <λ, and a depends on the distance z from the pinhole 14 is as follows.

[0058]

(Equation 2)

Where C is a proportional constant, and λ is the wavelength of the light irradiated to the pinhole 14.

[0060]

(Equation 3)

Is as follows. From (Equation 2), it can be seen that a decreases sharply in the region of z> 1 / γ. Therefore,
The interval h must be smaller than 1 / γ. As described above, the size D of the light spot must be at most the same as the size 1 of the recording mark. Here, if the wavelength λ is 780 nm and the light spot size D is 100 nm, 1 / γ ≒ 33 nm. That is, in order to record and reproduce a recording mark having a size of about 100 nm with light having a wavelength of 780 nm that has passed through the pinhole, the interval between the pinhole 14 and the recording film 10 needs to be approximately 33 nm or less.

For this reason, when a pinhole is provided in a slider and information is recorded / reproduced using light passing through the pinhole, the pinhole and the surface of the slider facing the information recording medium are extremely precisely positioned. There is a need. That is, the dent h of the core 3 in FIG. 2 needs to be 33 nm or less. In the method of the present invention, since the pinhole 14 is provided directly on the surface of the slider 1 facing the information recording medium 2, no positioning problem occurs. Further, as described above, since the pinhole 14 is provided in the recessed portion provided in the core 3, the pinhole 14 is provided in the information recording medium 2.
The probability of collision and destruction is very small.

Next, a second embodiment of the present invention will be described with reference to FIGS.

FIG. 8 is a sectional view of a slider on which the optical head of the present invention is mounted, and FIG. 9 is an explanatory view of a manufacturing process of the slider on which the optical head of the present invention is mounted.

The slider 71 shown in FIG.
The relative motion is performed at the relative speed v. The slider 71 has
Fluid force due to relative movement with the information recording medium 2 acts. The slider 71 is supported by the arm 70. When the above-described fluid force and the spring force of the arm 70 are balanced, the slider 71 is relatively moved while keeping the distance h from the information recording medium 2 constant.

The slider 71 has a core 73 and a clad 7
4. The optical fiber 72 composed of the coating 75 is
6 are adhered. A light-shielding film 77 is formed on a surface of the slider 71 facing the information recording medium 2. A pinhole 78 is provided in a portion of the light-shielding film 77 corresponding to the end face of the core 73.

A laser light source 79 installed on the opposite side of the slider 71 with respect to the information recording medium 2
Is irradiated with laser light. The transmitted light and scattered light of this light are extracted through a pinhole 78, propagated in the optical fiber 72, and detected by a photodetector not shown in FIG. The information recording medium 2 is the same as that of the first embodiment, and information recorded on the information recording medium 2 can be reproduced by light detected by a photodetector not shown in FIG. Also,
Slider 1 of information recording / reproducing apparatus described in the first embodiment
Is replaced with a slider 71, the photodetector 9 is replaced with a laser light source 79, and a photodetector for detecting light propagating in the optical fiber 72 is added, thereby reproducing information recorded on the information recording medium 2. A playback device can be configured.

The manufacturing process of the slider 71 will be described with reference to FIG.

First, a grooved substrate 80 and a substrate 81 as shown in FIG. 9A are prepared. As in the case of the second embodiment, since the optical fiber 72 is a silica-based optical fiber,
The material of the grooved substrate 80 and the substrate 81 is quartz. The shape of the groove of the grooved substrate 80 is such that the coating 75 of the optical fiber 72 fits into the groove. For example, the outer shape of the coating 75 is 250 μm
In this case, if θ = 90 ° in FIG. 9A, E should be larger than 306 μm. Considering a gap for filling the adhesive 76, E may be set to about 350 μm. The optical fiber 72 is inserted into the groove of the prepared grooved substrate 81, sandwiched between the substrates 81, and bonded with the adhesive 76. At this time, as in the case of the first embodiment, the length of the portion of the optical fiber 72 from which the coating 75 is removed is shorter than the thicknesses of the grooved substrate 80 and the substrate 81, and the adhesive is applied from above the coating 75. Do.

After bonding, polishing is performed so that the end surface of the optical fiber 72 and the upper surfaces of the grooved substrate 80 and the substrate 81 in FIG. At this time, it is necessary to perform bonding so that the coating 75 does not appear on the polished surface. First
As in the case of the embodiment of FIG.
0, when the upper surface of the substrate 81 and the end surface of the optical fiber 72 are the same surface, the grooved substrate 80, the substrate 81, the optical fiber 7
It is desirable that the second core 73 and the clad 74 have the same hardness. Because of this and the fact that the optical fiber 72 is a quartz fiber, the material of the grooved substrate 80 and the substrate 81 is quartz.

After the polishing, the grooved substrate 80 and the substrate 81 are processed into the shape of the slider 71 as shown in FIG.

After processing into the shape of the slider 71, the surface of the slider 71 facing the information recording medium 2 is subjected to etching, and the core 73 is recessed with respect to the clad 74 as shown in FIG. Thereafter, as in the case of the first embodiment, a light-shielding film 77 is formed on the surface of the slider 71 facing the information recording medium 2, and the FIB is irradiated by irradiating the FIB with the depression of the core 73 as a mark. To form The slider 71 can be manufactured by this process. In this case, the same consideration as in the first embodiment of the present invention is necessary for the recess amount of the core 73 and the distance between the surface of the slider 71 facing the information recording medium 2 and the information recording medium 2.

In the second embodiment, as a mark for performing FIB processing, the core 73 does not necessarily need to be concave, but may be convex. Such processing is performed by using an etchant for etching the end face of the optical fiber 72 using a solution obtained by mixing HF 50% aqueous solution, pure water, and NH4F 40% aqueous solution at a volume ratio of 1: 1: 2. Can be.

Although all of the embodiments described so far are directed to transmission type optical discs, the following description is directed to reflection type optical discs with reference to FIG.

FIG. 10 shows the configuration when the recording medium is of the reflection type.

Light emitted from the semiconductor laser 60 is condensed by the coupling lens 59 and is coupled to the optical fiber 62. The fiber folder 58 fixes the end face of the optical fiber 62 at the focal point of the coupling lens 59.
Light coupled to the optical fiber 62 propagates through the optical fiber 62, passes through the Y branch 61, and enters the optical fiber 12. The slider 1 has the same structure as the slider 1 of FIG.
A pinhole 14 is provided on the end face of the optical fiber 12. The light incident on the optical fiber 12 is applied to the information recording medium 2 through the pinhole 14. The information is recorded on the information recording medium 2 by modulating the light emitted from the semiconductor laser 60 as in the first embodiment.

Regarding the reproduction of information, the first and second
Unlike the embodiment, the reflection is performed by receiving light reflected from the information recording medium 2.

When a part of the recording film 10 constituting the information recording medium 2 has been removed or a phase change has occurred, the light radiated from the pinhole 14 onto the information recording medium is again transmitted to the pinhole 14. The light returns as reflected light, but the reflectance changes. For example, the reflectance of the portion where the recording film 10 has been removed is smaller than the reflectance of the portion where the recording film 10 has not been removed. When the recording film 10 is in an amorphous state as used in a phase change type optical disk device,
When in the crystalline state, the reflectance of irradiated light is different.

Therefore, information can be reproduced even when a constant light is irradiated and a change in the amount of reflection is detected. When reproducing information, the semiconductor laser 60 emits light of a constant intensity. This light is applied to the information recording medium 2 through the pinhole 14 as described above. The reflected light of this light again passes through the pinhole 14 and propagates in the opposite direction to that when it first propagated through the optical fiber 12. The light enters the Y branch 61. Light propagating in the optical fiber 12 and entering the Y branch 61 is split into two. One of the lights returns to the semiconductor laser 60 through the optical fiber 62. The other propagates in the optical fiber 63, enters the photodetector 9, and is converted into an electric signal.
The information recorded on the information recording medium 2 can be reproduced from the electric signal.

In this case, the substrate of the recording medium 2 does not necessarily have to be a transparent substrate, and an opaque substrate such as Al or Si can be used.

Further, in this embodiment, the slider 1 is provided with one optical fiber, the fiber is branched in the middle, and the information is reproduced by measuring the return light. It is also possible to adopt a configuration in which optical fibers are arranged at predetermined intervals and angles in one, and light is irradiated to the recording medium from one of them, and reflected light from the recording medium is received by the other one. . However, in this case, it is necessary to form two pinholes, and it is necessary to accurately arrange the pinholes.

[0082]

According to the present invention, pinholes can be mounted on the slider with a small increase in slider mass.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical head according to the present invention.

FIG. 2 is an enlarged sectional view of the optical head of the present invention.

FIG. 3 is an explanatory diagram of a manufacturing process of the optical head of the present invention.

FIG. 4 is a perspective view of an information recording / reproducing apparatus to which the optical head of the present invention is applied.

FIG. 5 is an enlarged view near an arm.

FIG. 6 is an enlarged view of an information recording medium of the information recording / reproducing apparatus.

FIG. 7 is an explanatory diagram of the operation principle of the present invention.

FIG. 8 is a cross-sectional view of the optical head of the present invention.

FIG. 9 is an explanatory diagram of a manufacturing process of the optical head of the present invention.

FIG. 10 is a configuration diagram of a reflection type optical head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Slider, 2 ... Information recording medium, 3 ... Core, 4 ... Clad, 5 ... Coating, 6 ... Arm, 7 ... Adhesive, 8 ... Contact pad, 9 ... Photodetector, 10 ... Recording film, 11 ... Substrate , 12 ... optical fiber, 13 ... substrate, 14 ... pinhole, 15 ... light shielding film, 21 ... base, 22 ... spindle motor, 23 ... positioning actuator, 24 ... interface, 25 ... connector, 26 ... system controller, 27 ... laser Light source, 32, 33, 34, 35, 36
... Track, 37 ... track identification mark, 38 ... wobble mark, 39 ... wobble mark prediction mark, 40 ... record mark, 41 ... pinhole locus, 51 ... loop, 5
2, 53: fixing jig, 54: θx support spring, 55: fixing part, 56: θy support spring, 57: intermediate holder, 58: fiber holder, 59: coupling lens, 60: semiconductor laser, 70: arm, 71 slider, 72 optical fiber, 73 core, 74 clad, 75 coating 75, 76 adhesive, 77 light shielding film, 78 pinhole, 79 laser light source, 80 grooved substrate, 81 substrate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akinchi Ito 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (3)

[Claims] 1. An optical head comprising: a slider which makes contact with an information recording medium or moves relative to the information recording medium at a predetermined interval; and a pinhole provided on a surface of the slider facing the information recording medium. An optical fiber is attached to the slider, and an end face of the optical fiber appears on a surface of the slider facing the information recording medium, and a thin film made of an opaque substance is formed on the end face of the optical fiber. An optical head, wherein the pinhole is provided in a core portion of the optical fiber of the thin film. 2. The optical head according to claim 1, wherein said slider and said optical fiber are made of a material mainly composed of the same substance. 3. An information recording medium on which information can be recorded or reproduced by an optical method, a light source, an optical head for irradiating a predetermined area of the information recording medium with light emitted from the light source, and the optical head. A light detector that detects transmitted light, reflected light or scattered light of light emitted from the head, and reads information recorded on the information recording medium therefrom, and a mechanism system that supports the optical head and moves to a predetermined position. An information recording / reproducing apparatus having a control circuit for controlling the positioning of the optical head at a predetermined position on the information recording medium, wherein the optical head attaches an optical fiber to a slider portion, and the slider faces the information recording medium. On the side
An information recording / reproducing apparatus, wherein a thin film made of an opaque substance is formed, and a pinhole is provided in the thin film portion so as to match a core portion of the optical fiber.