JP2000195093A - Optical storage head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical storage head that can efficiently output a laser beam and has structure that can be mass-produced accurately. SOLUTION: In an optical storage head, a number of vertical resonator light-emitting semiconductor laser elements 1 are arranged in nearly a matrix shape, and a laser beam transmission part 3 with conical structure where a tip becomes an output window for outputting evanescent waves is provided on each of the semiconductor laser elements 1. A multi-mode laser wave being generated in each of the semiconductor laser elements 1 is reflected on the inner surface of the laser beam transmission part 3, and an evanescent wave being outputted from the output window at the tip of the laser beam transmission part 3 is directed toward a storage. Therefore, a number of beam spots are formed on the storage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical memory head for reproducing information, recording information or reproducing information, and reproduces information on a large-capacity optical recording medium and a magneto-optical recording medium using, for example, a vertical cavity surface emitting semiconductor laser. Alternatively, the present invention relates to an optical memory head incorporated in an optical recording / reproducing apparatus for recording.

[0002]

2. Description of the Related Art In recent years, various types of optical recording / reproducing apparatuses have been developed. A conventional optical recording / reproducing apparatus uses a single semiconductor laser such as a laser diode, and converges a laser beam oscillated from the semiconductor laser into a spot beam, for example, a ROM disk such as a CD or DVD, an optical recording medium, or a magneto-optical device. And a converging optical element such as a lens that irradiates the recording medium. The optical recording / reproducing apparatus modulates a laser beam at the time of recording according to information to be recorded and irradiates the recording medium with the laser beam, and records the information on the recording medium as a physical change corresponding to the modulated spot beam. In addition, this optical recording / reproducing apparatus irradiates a spot beam of approximately constant intensity onto the recording medium during reproduction, and records by reflecting a physical change in the beam spot and demodulating a reflected light beam obtained from the recording medium. Play information. At present, a recording density of about 10 ⁷ to 10 ⁸ [bit / cm ² ] is realized by setting a beam spot to a fine diameter of about 1 [μm].

The above-described tracking of the optical memory head is performed by detecting header information of an optical recording medium or a reflected laser beam reflected from a tracking guide provided on the medium, and is controlled on the order of [0.1 μm] by an actuator. Since such control is usually performed using a laser beam generated from a single laser diode incorporated in an optical memory head, there are limitations on recording density and recording / reproducing rate.

Further, most of the conventional optical recording / reproducing apparatuses employ a floating head system in which an optical memory head performs a recording / reproducing operation without contacting the optical recording medium. A contact head system that performs a recording / reproducing operation while making contact has not been put to practical use.

Further, the conventional optical recording / reproducing apparatus can record a large amount of information on an optical recording medium or the like as the diameter of the beam spot is small. Since the optical memory head complies with the above requirements, the laser beam can be converged only to a diameter of about a fraction of the wavelength of the light to be used due to the limitation of the diffraction limit due to the wavelength of the light. Therefore, even in an optical recording medium having a diameter of 120 [mm], which is most commonly used every day, at most 1
Only a recording capacity of 0 [GB] can be secured, and it is considered that today's memory for multimedia communication has an insufficient capacity, and further recording capacity is required to strongly support rapid technical progress. The emergence of an epoch-making optical memory head that can be secured is keenly desired.

The inventor of the present application has proposed a system using the "contact head system" in the field of near-field optics in which an optical memory head comes into contact with an optical recording medium via a lubricant in a recording / reproducing operation in Japanese Patent Application No. 8-298981. are doing. In this system, a vertical cavity surface emitting semiconductor laser (Vertical Cavity Surface) is used.
Emitting Laser, simply referred to as VCSEL. ) Utilizing the principle, an optical memory head for recording / reproducing that can realize the principle is proposed. In this recording / reproducing optical memory head, a large number of vertical cavity surface emitting semiconductor laser elements are arranged in a lattice pattern, and ultrafine holes are provided in a laser beam transmitting portion of each semiconductor laser element.
According to this recording / reproducing optical memory head, it has been found that the recording density can be dramatically increased as compared with the conventional method evident from the principle, and a huge recording capacity can be secured.

The proposed optical memory head for recording / reproducing has a structure which can be incorporated into an actual device, and which can output a laser beam with high efficiency and which can be manufactured in large quantities with higher accuracy. The realization of an optical memory head is awaited.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical memory head having a structure capable of outputting a laser beam with high efficiency and capable of mass-producing with higher accuracy.

According to the present invention, a plurality of vertical cavity surface emitting semiconductor laser elements arranged substantially in a matrix are incorporated, and a laser element substrate structure in which a multimode laser wave is generated from a light source point of the laser element. A laser light transmitting portion having a conical structure whose inner surface reflects a multi-mode laser wave is provided on the laser element substrate structure, the tip being an output window for outputting an evanescent wave. An optical memory, comprising: a vertical cavity surface emitting semiconductor laser array, which is arranged in a large number of matrices, and comprises a laser light transmitting structure in which the large number of evanescent waves are directed to a recording medium, and a laser resonator. A head is provided.

More specifically, in order to provide a laser output window having a diameter shorter than the wavelength of the laser light in a vacuum in the laser light transmitting portion, a crystal that can be anisotropically etched, for example, S
A laser light transmitting structure in which pyramid-shaped or pyramid-shaped laser light transmitting portions are arrayed in a matrix from an i ₃ N ₄ crystal, a silicon crystal, or a gallium arsenide crystal is provided on a laser element substrate structure. . With such a structure,
An optical memory head including an efficient and highly accurate contact type vertical cavity surface emitting semiconductor laser array is realized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical memory head according to the present invention will be described below with reference to the drawings. Although the structure of the optical memory head is shown in FIG. 1, the memory head can reproduce information from various recording media as described later, or can record information on the recording medium. . Therefore, the optical memory head according to the embodiment of the present invention can be realized as a memory head for reproduction, a memory head for recording, or a memory head for recording and reproduction. In addition, the recording medium is a general term for a medium that can be optically reproduced or recorded, and an optical recording medium is an optical disc (CD-R, DVD-R) that is a so-called once-recordable optical recording medium. A rewritable optical recording medium such as a phase change optical disk (PC), an optical disk including a photon mode recording medium, or a magneto-optical recording medium, a so-called magneto-optical disk (MO).

FIG. 1 is a perspective view for explaining in principle the structure of an optical memory head according to an embodiment of the present invention, FIG. 2 is a perspective view showing a part of the optical memory head shown in FIG. 1, and FIG. FIG. 3 is a sectional view showing an internal structure of the optical memory head shown in FIGS. 1 and 2. In the optical memory head shown in FIG. 1, a vertical cavity surface emitting semiconductor laser (Vertical Cavi
ty Surface Emitting Race
r: Hereinafter, referred to as “VCSEL element”. ) Are arranged in a lattice, that is, in a matrix. This VCSEL
The element 1 is formed on a substrate portion 2 having a predetermined thickness including a multilayer reflective film laser active layer 5 for oscillating a laser beam as shown in FIG. In other words, a large number of laser light source points, each of which emits a laser beam, are formed in a matrix on the substrate section 2 on which a number of VCSEL elements 1 are formed. On this substrate section 2, a large number of laser light transmitting sections 3 corresponding to the VCSEL elements 1 are arranged in a grid pattern, that is, in a matrix at a predetermined pitch, for example, a constant row pitch E along a row and a constant row along a column. Are arranged at the column pitch F.
The laser light oscillated from the VCSEL element 1 is directed from the laser light transmitting unit 3 to the optical recording medium, and forms a laser beam spot on the optical recording medium.

The laser beam transmitting section 3 is formed as a substantially pyramid-shaped (pyramid-shaped) or substantially cone-shaped pyramid total reflection prism. It has an emission part for emission toward. The laser beam transmitting section 3 can be formed using silicon (Si) crystal or gallium arsenide (GaAs) crystal or the like. The above-mentioned crystal material may be replaced with another crystal material as long as the material has a higher refractive index than the atmosphere in contact with the laser beam transmitting section 3 and is capable of totally reflecting the laser wave inside.

The tip 4 of the laser beam transmitting section 3 having a cantilever structure has a small area on one side, for example, about 10 to 2
A tip portion that allows evanescent light of 0 [nm] square, preferably approximately 10 [nm] in diameter, to pass through is provided.
As shown in FIG. 3, the multimode oscillation laser wave generated by the oscillation in the substrate section 2 is repeatedly reflected on the prism surface of the laser beam transmitting section 3 and in the substrate section 2 so that the tip section 4 through which only evanescent light can pass. Emitted from. The evanescent light is radiated vertically from the tip 4 and directed to the recording medium. The other laser light is totally reflected by the prism surface of the crystal, is encapsulated therein as a reflected laser light, and is prevented from being led out of the laser light transmitting unit 3. In the optical memory head shown in FIG. 1, since the laser beam transmitting units 3 are arranged in a matrix at a constant pitch, the row pitch E and the column pitch F are substantially equal to those of the laser beam transmitting unit 3. It is defined as the distance between the tips 4.

In order to actually manufacture a vertical cavity surface emitting semiconductor laser array A (hereinafter simply referred to as VCSEL array A) as an optical memory head in which a plurality of VCSEL elements 1 are arranged at regular intervals in a grid pattern, The VCSEL elements 1, 1,... Are simultaneously formed in a lattice shape by an ordinary etching method or the like. Conceptually, VCS
A part of the EL array A includes a plurality of VCSEL elements 1, 1,
Are joined and arranged, and the laser beam transmitting unit 3 is arranged on the element 1.

FIG. 4 shows a method of manufacturing the laser beam transmitting section 3.
This will be described with reference to FIG.

First, as shown in FIG. 4A, a single crystal silicon (Si) substrate 10 as an intrinsic semiconductor is prepared, and an SiO ₂ film 11 covering the entire substrate is formed by an oxidation furnace. Thereafter, a resist such as PMMA is applied on one surface of the silicon substrate 10 by a spin coater, and the silicon substrate 10 is placed in an oven and post-baked to form a resist film RS. This resist film RS
Is exposed by an exposure machine through a glass mask on which a square or circular pattern is drawn. The square or circular pattern is reduced or reduced by one to one on the resist film RS at the time of exposure. After this exposure, the resist film RS is selectively removed by a developing process, and is formed in a square or circular shape.
A resist pattern exposing the O ₂ film 11 is formed. Subsequently, an etching process using hydrofluoric acid is performed to etch the exposed portion of the SiO ₂ film 11. In this etching process, the Si substrate 10 as the lower layer of the SiO ₂ film 11 is
It is not etched until. After the etching process, the resist film RS is peeled and removed with acetone.

Next, TMAH: NCW or KOH (hydroxylation
(Aqueous potassium solution) _TwoMasked with membrane 11
Etching of exposed silicon substrate 10
Treat it as a pyramid or conical depression as shown in FIG.
12 is formed. KOH is applied to the (100) plane of silicon.
And etching at an angle of 55 °.
Etching is performed at an angle of °. SiO_TwoThe film 11 is made of silicon
Ammonium fluoride mixed after etching treatment of substrate 10
Removed with liquid.

Next, the thus obtained silicon substrate 10
Is again oxidized in a steam furnace to form a thin SiO ₂ film 13 covering the entire surface of the silicon substrate 10 as shown in FIG. When the silicon substrate 10 is returned to normal temperature, the SiO ₂ film 13 forms a crack at the apex of the depression 12 due to the difference in expansion coefficient between Si and SiO ₂ . S on this crack
CVD of Si ₃ N ₄ , a material having a higher refractive index than iO ₂
Alternatively, an Si ₃ N ₄ core PR is formed by ECR sputtering to fill the entire recess 12 as shown in FIG. 5D. In the above deposition process, G ₃ was used instead of Si ₃ N _4.
A high refractive index material such as aP may be used.

Next, the Si on the back side of the silicon substrate 10
The O ₂ film 11 is removed, and then the silicon substrate 10 is selectively etched by a predetermined thickness so that the tip of the conical or pyramidal prism projects as shown in FIG. After this,
A laser reflecting mirror is formed by covering the surface of the Si ₃ N ₄ core (or GaP core) PR with an antireflection film. The laser beam transmitting structure 14 corresponding to the laser beam transmitting section 3 is formed in this manner. As shown in FIG. 5F, light incident at an angle equal to or smaller than the light confinement angle is confined and guided to the tip 4. However, since the light at the angle of the light confinement angle limit is not fully reflected on the way, it is effective to form a metal film on the outermost side of the prism.

The laser beam transmitting structure 14 is closely bonded to the substrate section 2 to form a vertical cavity surface emitting semiconductor laser array A.

In the VCSEL array A shown in FIG. 1, one column of evanescent light emitted from the VCSEL elements 1 arranged in the same row is placed on a recording layer of an optical recording medium or a magneto-optical recording medium (not shown). Irradiated to form a beam spot corresponding to the number of elements in a row, and if the recording medium is rotated, a beam locus corresponding to the number is formed on the recording medium.

Hereinafter, for the sake of convenience, V
VCSEL in which CSEL elements 1 are arranged in 5 rows and 5 columns
The array A will be described. In this specification, a row C refers to a row arranged along a tangential direction K of a rotation direction of the optical recording medium, and a column L refers to a row arranged along a radial direction of the optical recording medium. .

In the five rows and five columns of the VCSEL array A shown in FIG. 1, a total of five evanescent lights are emitted from the five VCSEL elements 1 arranged in the fifth row and the first column to the fifth column. A is emitted in a direction perpendicular to A. Therefore, five beam spots are formed on the recording layer 16 of the optical recording medium disposed so as to face the VCSEL element 1. Normally, information is recorded and reproduced on the optical recording medium by rotation, so that the locus of five evanescent lights is drawn on the recording layer 16. Here, the tangent K of rotation of the optical recording medium
When the optical recording medium and the VCSEL element 1 are arranged so that the row direction L of the VCSEL element 1 and the row direction L are parallel to each other, the loci drawn by the five beam spots on the recording layer overlap and become one. That is, the optical recording medium cannot be scanned with substantially five evanescent lights. Therefore, in the VCSEL array A shown in FIG.
As shown in FIG. 6, the row direction L of the VCSEL array A is inclined at a predetermined minute angle (with respect to the tangent line K of rotation of the optical recording medium. In this case, five beams are provided. The spots are arranged in the same row and adjacent rows.
Two beam spots formed by two VCSEL elements 1, that is, overlapping between the two beam spots formed by VCSEL elements 1 located in the fourth row and the first column and the fifth row and the first column in the case described above. It can be arranged without. However, the VCS located at the third row and the first column, which is the end point,
One beam spot formed by the EL element 1 has the above-mentioned 5 spots.
Shall be included in the number of beam spots. Therefore, FIG.
When the optical recording medium rotates as shown in FIG. 5, five continuous non-overlapping trajectories can be drawn on the recording layer, so that information can be recorded / reproduced on five tracks.

Based on the above operation, the VCSEL array A
In the case where the number of VCSEL elements 1 is further increased, the number of tracks that can be simultaneously recorded and reproduced can be increased. An embodiment in which the number of tracks is increased as described above will be described next.

FIG. 7 shows a VCSEL array A having N rows and M columns.
In this VCSEL array A, as shown in FIG. 8, a row L of the VCSEL array A has a predetermined minute angle (with respect to a tangent K in a rotation direction of a recording medium 15 such as an optical disk rotated about a center O as a rotation center. In this arrangement, the VCSEL array A of N rows and M columns irradiates the recording medium 15 with MxN lasers, and the surface thereof has MxN lasers. Therefore, the MxN locations are simultaneously searched, and information is written into the MxN locations by the VCSEL array A, and the information is read from the MxN locations.

FIG. 9 shows the recording VCS shown in FIG.
A reproduction system for reproducing information recorded by an EL array A head is shown. In this playback system, VCS
The information recorded on the recording medium 15 is read by monitoring the presence or absence of laser oscillation of the EL element 1 and making the presence or absence correspond to binary information. Specifically, depending on the presence or absence of the information bits recorded on the recording medium 15, for example, when the information bits are present, if the information bits are set to a crystalline state having a high reflectance, the light reflected on the information bits Is 10 [n] obtained by etching the VCSEL element 1.
m] square or a diameter of 10 [nm], and enters the VCSEL array A through a laser beam passing tip, and
Excitation of the element 1 causes laser oscillation. Conversely,
When the information bit does not exist, the reflection of the laser light is suppressed in a region where the information bit does not exist by setting the information bit in an amorphous state having a low reflectance, and the light reflected by the information bit is emitted from the laser of the VCSEL element 1. Even if the VCSEL element 1 is returned to the light passing front end and enters the VCSEL element 1, it does not cause the VCSEL element 1 to perform laser oscillation. Therefore, the presence or absence of laser oscillation can be monitored, and these can be made to correspond to binary information.
Information recorded by the L array A head can be read.

The etching surface formed in a pyramid shape by the etching process utilizing the crystal plane of the crystal constituting the VCSEL element 1 completely reflects the laser light emitted from the VCSEL element 1, and particularly, It is not necessary to provide a metal thin film or the like for preventing transmission on the etched surface of the VCSEL element 1 other than the laser light passing end of the VCSEL element 1. Here, the laser beam passage tip of the VCSEL element 1 has a diameter of 10 [nm], and is left by fine adjustment of the crystal surface etching process.

During reproduction, an injection current is constantly applied to each VCSEL element 1 to maintain the VCSEL element 1 in an oscillation state. In this case, above the laser beam passing tip 4,
Even if a low reflectance information bit recorded on a recording layer such as the optical recording medium 15 is positioned, the injection current is adjusted to such an extent that the VCSEL element 1 is not excited by the reflected light. By adjusting the injection current in this way, it becomes possible to read information bits recorded on the optical recording medium by the mechanism described above. Although the recording optical memory head and the reproduction optical memory head are separately described here for the sake of explanation, it is also possible to share recording and reproduction with the optical memory head.

In a conventional optical memory disk recording / reproducing apparatus using a light emitting diode or the like, the conventional head portion is replaced with the recording / reproducing optical memory head of the present invention, and a conventional air flow floating head or a conventional electromagnetic force / spring is used. If the floating head according to the above is adopted as the contact head system of the prior art, an ideal optical memory disk recording / reproducing apparatus can be constituted as an embodiment of the present invention. Here, the contact head method is a recording / reproducing method in which a recording / reproducing optical memory head is brought into contact with an optical recording medium or the like via a lubricant, and a conceptual diagram of the embodiment is shown in FIG. I have. The optical recording medium 15 and the like are placed horizontally on the optical disk substrate 19 with the recording surface facing upward. The surface of the optical disk substrate 19 serving as the recording surface has a thickness of 5 to 10 mm.
An optical recording medium layer 15 of about [nm] is provided, on which a recording medium protective film 1 made of Si ₃ N ₄ , SiO ₂ or the like is formed.
On the surface of No. 0, a thin film 14 of a lubricant such as perfluoropolyether having a thickness of about 1 [nm] is formed. The optical memory head section A is arranged so that the laser output section faces downward. The optical memory head part A includes two circular reading pads 22 and one circular trailing pad 23 having a diameter of 100 [μm] provided on the bottom surface.
Are supported on the optical recording medium 15 via the lubricant 14 by only a total of three points, and are lightly pressed from above by a suspension gimbal obtained by perforating a commercially available one. In this way, a so-called meniscus is formed around the circular trailing pad 13 and the circular leading pad 12 by the surface tension of the lubricant 14. Due to the tension of the meniscus, the amount of jump when the optical recording medium 15 or the like rotates is reduced, and the optical recording / reproduction is stably performed.

Further, as shown in FIG. 10, the λ / 4 film 25 and the Faraday rotator film 2 are provided in the optical memory head A.
By forming 6, an ideal magneto-optical memory head can be provided. The read / write method is the same as that of the prior art. However, as shown in FIG. 10, a VCSEL element 1 is coated by ECR sputtering between a substrate portion 2 comprising an n-AlGaAs / GaAs multilayer reflection mirror and a laser active layer. So-called λ / 4 film 1 having orientation
5, and a Faraday rotator film 16 is formed. Assuming that a TE wave is generated by the VCSEL element 1, the TE wave reflects off the λ / 4 film on the magneto-optical recording medium 15, and
When the light wave enters the ４ film and returns to the laser active layer, the electric field component of the light wave becomes a TM wave having a 90 ° oscillation direction different from that of the TE wave. If information bits due to the difference in the direction of magnetization are recorded on the magneto-optical recording medium 15, TE generated in the VCSEL array A reflected by the optical disk medium 15,
A phase difference appears between the TM waves. Here, a Schottky diode is inserted between the multilayer reflection mirror and the GaAs substrate, and a high frequency corresponding to a frequency for two light waves is generated according to the magnetization direction of the magneto-optical film. As in the prior art, information can be recorded and reproduced by detecting this high frequency. When the present magneto-optical memory head is configured, a magnetic material is required for recording. Therefore, the periphery of the recording and reproducing VCSEL array A is covered with a magnet or a magnetic material necessary for magneto-optical recording. The magnetic field of the Faraday optical element and the magnetic field for magneto-optical recording are also used.

Next, referring to FIG. 11, a functional conceptual diagram of the optical memory head according to the present embodiment, in which a faulty element compensation array is provided, will be described.
When some VCSEL elements 1 fail in the VCSEL array A, the failed element is replaced with another VCSEL element 1 without replacing with a new VCSEL array A. That is, another VCSEL array A identical to the VCSEL array A is provided in advance. Specifically, the first
Of the first VCSEL array A and a spare element identical to the VCSEL array A, and the first VCSEL array A has a faulty element in the first row and the tenth column as (1, 10). In other words, the second VCSEL
The corresponding compensating element in array A is the first row 10
The column, ie, (1, 10). First VCSE
The laser light of (1, 10) of the L array A is
Since the trajectory drawn on 5 is the same as the trajectory of the (1, 10) laser beam of the second VCSEL array A, the first VCSEL is operated by a signal controller (not shown) or the like.
The VC of (1, 10) of the normal second VCSEL array A is detected at the same time when the failure of (1, 10) of array A is detected.
The SEL element 1 can be used for compensation.

VC provided to the optical memory head of the present embodiment
The structure of the SEL array A will be described below in more detail. VCSE as shown in FIG. 1 and FIG.
The L array A includes a plurality of VCSEL elements 1, individual electrodes, and a common electrode. The VCSEL element 1 includes a substrate unit 2 and a laser beam transmitting unit 3. This VCSEL
The element 1 has a laser beam transmitting unit 3 having a diameter of 1 [μm] and each V
Ideally, the interval between the CSEL elements is a grid-like square of 2 [μm]. Here, as an optimal configuration, the VCSEL elements 1 are arranged so as to form 100 grid square columns in the row L direction and 100 grids in the column C direction. The tip 4 of the cantilever 5 corresponding to each VCSEL element 1 is provided with a square ultrafine laser transmitting hole 4 with a side of about 10 [nm]. The ultrafine laser delivery hole 4 is
A plurality of ultra-fine laser transmission holes 4 are formed by etching a Si ₃ N ₄ solid crystal and the like, and are brought close to the center of the laser light transmission section, and then gently pressed to precisely form a super-laser. A fine laser delivery hole 4 can be provided. The ultrafine laser transmitting hole 4 functions as an output window for emitting an evanescent light wave generated by the VCSEL element 1 to the outside as a light beam. Although the laser beam transmitting section 2 is formed as a column having a small height, the laser beam transmitting section 2 can take any three-dimensional form such as a square, a rectangular shape, or the like.

VCSEL array A having 100 rows and 100 columns
Is arranged as shown in FIG. 8 for recording information on the optical recording medium 15, and is incorporated in a system as shown in FIG. For the sake of simplicity, the VCSEL array A is set to be horizontal with the ultrafine laser transmitting hole 4 as described above, and the optical recording medium 15 is positioned above the minute distance so that the recording layers are parallel and opposed. It is assumed that it is arranged in. 10
A total of 10,000 laser beams emitted from the VCSEL array A in the 0th row and 100 columns in the vertical direction form a total of 10,000 beam spots over a width of about 200 [μm] on the recording layer of the optical recording medium 15. Note that, as in the case of the ordinary recording method for the optical recording medium 15, the point at which the beam spot hits causes a depression or a change in reflectance or a physical change as discoloration depending on the material of the recording layer. Information is recorded by a known method corresponding to the value signal.

Here, as shown in FIG.
If the array A is installed at a small angle with respect to the tangential direction (tangential direction) of rotation of the optical recording medium, the recording layer of the optical recording medium 15 may have an interval of about 20 [nm] width.
It becomes possible to draw 10,000 trajectories by continuous 10,000 beam spots that do not overlap. More specifically, a VCSEL array A of 100 rows and 100 columns forming 10,000 beam spots having a width of 200 [μm] is arranged such that θ = arctan with respect to a tangential direction (tangential direction) of rotation of the optical recording medium. (2/199) =
Install at an angle of 0.57582 degrees. Then, on the recording layer of the optical recording medium, the distance between the beam spots is about 20.
It is possible to draw 10,000 non-overlapping continuous loci having a width of [nm]. If the input / output signals of each VCSEL element 1 are individually subjected to high-speed pulse modulation in this state, information for 10,000 tracks, that is, 10,000 [bits] can be simultaneously recorded and reproduced. Therefore, the light having a width of 200 [μm] irradiated on the recording layer of the optical recording medium is 1
The 0000 laser beams have a disk tangential velocity of 10
[Mm / sec], 1 [Mbit] per track
/ S], that is, 10 [G
bit / s]. As a result, about 1 [TByte] of information can be recorded in total on an optical recording medium having a diameter of 120 [mm].

Here, a method of obtaining a small angle when the VCSEL array A is inclined will be described. In the VCSEL array A, as shown in FIG. 7, N represents the number of VCSEL elements 1 arranged in the radial direction (column direction) of the optical recording medium, and VCSEL elements 1 arranged in the tangential direction (row direction) of rotation of the optical recording medium. Assuming that the number is M, the laser beam transmitting unit 3 of the VSEL array A
Is D, the distance between adjacent laser light transmitting units 3 and 3 in the column direction is E, and the distance between adjacent laser light transmitting units 3 and 3 in the row direction is F. The length between the ends is expressed as MD + (M-1) F, and the length between the outer ends in the column direction is expressed as ND + (N-1) E.
Further, the internal interval of one of the adjacent laser beam transmitting units 3 and 3 in the column direction is E + D. Accordingly, when all the M × N laser beams emitted from the VCSEL array A can draw a trajectory without continuously overlapping, the angle θ that forms a tangent to the rotation of the optical recording medium is θ = arctan ｛ (D +
E) / [MD + M-1) F]｝ Here, θ is the angle between the row direction of the VCSEL array A and the tangential direction of the rotation of the optical recording medium.

According to the above-described embodiment, a vertical cavity surface emitting semiconductor laser array A in which the vertical cavity surface emitting semiconductor laser elements 1, 1,... By using an optical memory head for recording and reproduction, it becomes possible to form a plurality of beam spots having a size equal to or less than the theoretical limit value in the optical element, and a remarkably large capacity as compared with a conventional optical memory head. Recording and reproduction on an optical recording medium or a magneto-optical recording medium.

The vertical cavity surface emitting semiconductor laser array A is a recording / reproducing optical memory head which is inclined at a predetermined minute angle with respect to the tangential direction of rotation of the optical recording medium. The laser beam from the ultrafine laser delivery hole 4 can easily form many recording / reproducing tracks on the recording layer of the optical recording medium or the magneto-optical recording medium.

Further, a plurality of beam spots formed by the laser light emitted from the vertical cavity surface emitting semiconductor laser device 1 in the same row are formed by two vertical cavity surface emitting semiconductor laser devices arranged in the same row and adjacent rows. Since the recording / reproducing optical memory head is disposed between the recording and reproducing tracks 1, 1 and 1, even if the number of recording and reproducing tracks is extremely large,
Without overlapping, it can be reliably formed on the recording layer of the optical recording medium or the magneto-optical recording medium, and can be configured with a large number of beam spots within the minimum unit area.

Further, a vertical cavity surface emitting semiconductor laser array A for compensating for a failed element is separately provided in parallel with the vertical cavity surface emitting semiconductor laser array A. The recording / reproducing optical memory head in which the ultra-fine laser emission holes in the same row and the same row are present on the same track can secure a compensating optical memory head and make a leap as compared with the conventional optical memory head. A large amount of information can be recorded and reproduced on an optical recording medium or a magneto-optical recording medium with extremely high reliability and reliability.

In FIG. 2, the laser beam transmitting section 3 is shown as a substantially quadrangular pyramid (pyramid) total reflection prism. However, when the laser light transmission section 3 is a substantially conical total reflection prism, it is shown in FIG. It is formed as follows.

In the semiconductor laser array, an edge emitting semiconductor laser may be used instead of the vertical cavity surface emitting semiconductor laser. In this case, the two end faces of the edge emitting laser are such that the antireflection film has a semiconductor laser active material constituting the semiconductor laser and the end face refractive index of the laser resonator and the reflectivity at the interface between the air and the interface are infinitely close to zero. Laser beam transmitting section 3 which becomes one of the above and a cone-shaped total reflection prism
And a high-reflectance mirror is formed so as to cover the non-output surface of the laser beam transmitting unit 3 and the other end surface of the edge-emitting laser, respectively. It is obtained between the reflectance mirrors.

[0043]

As described above, according to the present invention, it is possible to obtain an optical memory head having a structure that can output a laser beam with high efficiency and that can be mass-produced with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical memory head for explaining the present invention in principle.

FIG. 2 is a perspective view showing a part of the optical memory head shown in FIG.

FIG. 3 is a cross-sectional view showing an internal structure of the optical memory head shown in FIG.

FIGS. 4A to 4C are views for explaining a method of manufacturing the laser beam transmitting section of the optical memory head shown in FIG. 1;

5 (d) to 5 (f) are views for explaining a method of manufacturing the laser beam transmitting section of the optical memory head shown in FIG.

FIG. 6 is a perspective view showing an arrangement relationship between the optical memory head shown in FIG. 1 and an optical recording medium.

FIG. 7 is a plan view showing a practical example of the optical memory head shown in FIG. 1;

FIG. 8 is a plan view showing a planar arrangement relationship between the optical memory head and the optical recording medium shown in FIG.

FIG. 9 is a sectional view showing an outline of a system adopting a contact head system in which the optical memory head shown in FIG. 1 is incorporated.

FIG. 10 is a sectional view showing a modification of the optical memory head shown in FIG.

FIG. 11 is a plan view for explaining an outline of a system capable of compensating for a defect in which a set of the optical memory head shown in FIG. 1 is prepared.

FIG. 12 is a perspective view showing a part of an optical memory head in which a laser beam transmitting section is constituted by a conical total reflection prism.

[Explanation of symbols]

 A: vertical cavity surface emitting semiconductor laser array 1: vertical cavity surface emitting semiconductor laser element 2: substrate unit 3: laser beam sending unit 4: ultra-fine laser sending tip

Claims (6)

[Claims] 1. A laser device substrate structure in which a number of vertical cavity surface emitting semiconductor laser devices arranged in a substantially matrix shape are incorporated, and a multimode laser wave is generated from a light source point of the laser device. Provided corresponding to the point, the tip is an output window for outputting an evanescent wave, the inner surface has a laser beam sending portion having a cone-shaped structure that reflects a multi-mode laser wave, a large number of matrix on the laser element substrate structure. An optical memory head, comprising: a vertical cavity surface emitting semiconductor laser array, which is arranged and comprises: a laser beam transmitting structure for directing the plurality of evanescent waves toward a recording medium; and a laser resonator. 2. The vertical cavity surface emitting semiconductor laser array, wherein the laser beam transmitting section is arranged so that a specific arrangement direction of output windows thereof is inclined at a predetermined minute angle with respect to a tangential direction of rotation of the optical recording medium. The optical memory head according to claim 1, wherein the optical memory head is configured. 3. A plurality of beam spots formed by laser light emitted from a vertical cavity surface emitting semiconductor laser device arranged on the same row are two vertical cavity surface emitting semiconductors arranged on the same row and adjacent rows. 2. The optical memory head according to claim 1, wherein the optical memory head is arranged between beam spots formed by laser light emitted from the laser element. 4. A semiconductor laser array is provided in parallel with the vertical cavity surface emitting semiconductor laser array. When a semiconductor laser element in the semiconductor laser array has a defect, the semiconductor laser element is replaced with another semiconductor laser element. The corresponding semiconductor laser element in the semiconductor laser array is operated complementarily, and a track to be searched for the laser light from the defective semiconductor laser element is searched by the laser light from the corresponding semiconductor laser element. The optical memory head according to claim 1. 5. A laser device substrate structure in which a large number of edge emitting semiconductor laser devices arranged substantially in a matrix are incorporated, and a multi-mode laser wave is generated from a light source point of the laser device. Provided, the tip is an output window for outputting an evanescent wave, the inner surface is a large number of laser light transmitting portions having a cone-shaped structure that reflects a multi-mode laser wave are arranged in a matrix on the laser element substrate structure, An optical memory head comprising: an edge emitting semiconductor laser array comprising: a laser beam transmitting structure for directing a large number of evanescent waves to a recording medium; and a laser resonator. 6. A gap is provided between one end face of the edge emitting semiconductor laser device and a tip of a cone-shaped laser beam transmitting portion, and an antireflection film is formed on a semiconductor laser device. Covering one end face of the edge emitting semiconductor laser element and the face facing the tip of the cone-shaped laser light transmitting portion so that the refractive index at the boundary between the end face refractive index of the vessel and the air is as close to zero as possible. And a high-reflectance mirror is formed so as to cover the non-output surface of the laser beam transmitting section and the other end surface of the edge-emitting laser element, respectively, and the laser resonator is obtained between these high-reflectivity mirrors. The optical memory head according to claim 5, wherein