JP2001134980A - Optical information recording medium and optical recording and reproducing device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording medium with which high-speed reproduction is possible in spite of high-density recording. SOLUTION: The optical information recording medium, which has a substrate and a recording film formed directly or via another layer on this substrate to write and read out information by changing the reflectivity, transmittance or intensity distribution of incident light, has guide grooves for specifying the position on the substrate for writing or reading out the information and a recording layer composed of recording ridges consisting of surfaces which are formed along these guide grooves and have a prescribed angle with the substrate or the surfaces parallel with the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium which can be read or written at a high recording density and which can operate at high speed, and an optical recording / reproducing apparatus using the same.

[0002]

2. Description of the Related Art With the rapid development of the multimedia society in recent years, the demand for large-capacity, high-speed optical communication for exchanging more information is ever increasing.

At present, electric signals transmitted from a plurality of information oscillating sources such as homes and offices via telephone lines are collected by a relay station for long-distance communication, where the electric signals are converted into optical signals. Many optical signals are transmitted through optical fiber
The signal is sent to another relay station at a distance of m, where it is converted into an electric signal again and sent to the intended information receiving source.

In addition to the increase in the number of information oscillation sources using optical communication, the information to be transmitted is not only a simple voice, but also has a larger capacity such as a data file or an image of a computer. It is required to exchange at high speed.

[0005] In order to further increase the speed, electric signals from all information oscillation sources are being converted into optical signals. As a countermeasure for this, the signal amount per unit time is increased by using shorter optical pulses.

[0006] A medium for storing such a large amount of information is also required to have a large capacity at the same time. Today, the most widely used media for storing such a large amount of information are various types of optical disks.
D).

[0007] An optical disk records and stores information on a disc-shaped substrate such as polycarbonate or glass based on the presence or absence of a spot region having a local reflectance or transmittance different from that formed by a laser beam. This is a recording medium for reading information from a change in intensity of reflected light or transmitted light when the spot area is scanned.

[0008] A read-only disk (Read o
nly OD) and optical recording disc (Optical recording di
sk or Direct read after write (DRAW), and the latter optical recording disk is erasable and writable with a write-once optical disk (Write once OD or Add on OD), which is a permanent record once recorded. It is classified as a rewritable optical disk (Erasable OD).

[0009] Depending on the recording method, a write-once optical disk among optical recording disks has a hole type, a phase change type, an alloy type,
There is a bubble type, etc., which cannot be tampered with, and is used for archival documents, books and drawings, suitable for long-term storage, transaction history information such as bank checks, and medical information files.

[0010] Rewritable optical disks among optical recording disks are classified into a magneto-optical type and a phase-change type depending on the recording method, and are used for file servers for information storage management of computers and for editing moving pictures for broadcasting. I have.

In a reflection type optical disk widely used today, first, a master disk and a stamper are precisely manufactured, and then a large number of replica optical disk substrates are manufactured. The procedure is as follows. First, the surface of a glass disk substrate as a master is polished and washed, and then a positive type photoresist is applied to one side of about 0.1 μm and dried.

A hole having a length of 0.6 to 3 μm and a width of 0.4 μm called a pit or a 0.4 μm width called a groove is guided on this surface by using an argon laser or a He—Cd laser having a wavelength of 450 nm. The shape of the groove is latently imaged (the resist is locally decomposed and becomes soluble and is removed).
These bits or grooves are formed in a spiral shape called a track in a disk, and the track interval is a CD.
Is 1.6 μm.

When this photoresist is developed with an alkaline solution, the resist is removed only from the portion previously irradiated with the laser beam, and pits or grooves are formed in the photoresist. The one created in this way is called a master.

After depositing a Ni plating layer as an electrode layer and further plating Ni to a greater thickness, the plated material is peeled off from the glass disk to form a metal disk called a stamper with reversed irregularities. Using this stamper, a pit or groove pattern of the master is transferred onto a transparent substrate of an optical disc to form a replica.

As the material of the substrate, transparent glass or plastic such as polymethyl methacrylate resin (PMMA) or polycarbonate resin (PC) is used.

There are two types of replica formation: an injection molding method and a 2P method. In the injection molding method, the stamper is used as a mold,
The molten resin is injected into a mold, and after cooling and solidifying, is taken out of the mold to form a replica. Since resin pellets can be used as a raw material and can be processed into a disk shape at the same time as the fine unevenness of the substrate surface, it is suitable for mass production at low cost, but birefringence is likely to occur due to distortion during molding.

In the 2P method, a photocurable resin is applied on a stamper, a glass or plastic disk is superimposed thereon, and the resin is polymerized by irradiating ultraviolet rays from the substrate side, and then the stamper is peeled off. Replicas are formed. 2
The P method is inferior in productivity to the injection molding method, but has high molding accuracy and little distortion, so that a highly reliable glass substrate or a low distortion plastic substrate can be used.

In this way, an optical disk substrate on which predetermined pits or grooves are formed in advance is formed, and in the case of optical recording, these previously formed pits or grooves are used to distinguish them from bits to be recorded later. Also, it may be called a pre-pit or a pre-groove.

Next, in the method of writing information, in the case of a reflection type optical disk, a laser beam is focused on a specific area.
Based on the difference in reflectance on the surface, it is detected whether or not there is a pit in which information is written. For this reason, various devices have been devised according to the recording method so that the detection sensitivity becomes the best.

For example, in a read-only disc, the prepit itself functions as an information recording layer, and a reflective layer of Al is deposited on an optical disc substrate. The height of the pit is set to １ ／ of the wavelength of the laser to be used. When the light incident from the transparent substrate surface is reflected by the reflective layer, the pit has a portion with and without a pit. Is set so that the optical path difference of the reflected light occurs, and the light from the existing part is canceled out by the interference.

In an optical recording disk, a recording layer for writing information by a user later, or a reflective layer of Al is deposited on the optical recording disk. The area where information is written as a new pit is either a groove or a flat surface between the grooves (called a land).

In this case, a groove for the guide groove is required for positioning for writing the information pit later. The height of the groove is set to 1/4 of the wavelength of the laser to be used, and is used for positioning of laser focusing. A laser beam is focused on a specific area of the recording layer where information is written, and the temperature of the recording layer is locally increased by a photoisomerization reaction (such as a spiropyran dye) or a magnetic field. Change and write information.

In a write-once optical disk, a hole-piercing type (Se-T)
e-based alloy and cyanine dye film melting or evaporation), phase change type (crystallization of amorphous alloy such as Sb-Se-Te), alloy type (alloy of SbSe / BiTe multilayer film), bubble type (organic And the like, and a magneto-optical type (a magneto-optical Kerr effect of a TbFeCo film or a TbFeCo / TbDyFeCo _two- layer film) and a phase-change type (GeSbTeCo film) on a rewritable optical disk. Crystal / amorphous change) and the like.

The factor that determines the recording density of these optical discs is the diameter of the focused laser beam. In general, it is assumed that the laser to be irradiated is a parallel Gaussian beam, the diameter of the parallel incident light beam is D, the wavelength of the light is λ, the beam waist diameter at the focal point, that is, the focused spot diameter is d, and the numerical aperture of the focused lens is N.
A, if the focal length of the lens is f and the light collection angle is θ,

[0025]

D = 2 × 0.41λ / NA (1) NA = sin θ = W / √ (W ² + f ² ) (2) where W = D / 2.

For example, a He-Ne laser (wavelength 632.
When a lens having a numerical aperture of 8 nm) and a numerical aperture of 0.4 is used, the focused spot diameter becomes 1.3 μm.

On the other hand, the width of the pre-pit is about 0.4 μm, and the reading light applied to this position covers the entire pre-pit. As described above, in order to improve the recording density of the optical disk, it is necessary to reduce the diameter of the focused spot.
Alternatively, either method of increasing the numerical aperture NA is adopted.

The application of short-wavelength lasers to optical disks has been studied as the most direct method for improving the recording density. For example, a laser beam having a wavelength of 780 nm is used for a compact disk for music (CD), while a laser beam having a wavelength of 650 nm is used for a digital video disk (DVD), whose demand is increasing in recent years.

Although these mainly use GaAsAl-based semiconductor lasers, in recent years, semiconductor lasers having shorter wavelengths have been realized with ZnSe-based or GaN-based semiconductor lasers.
Investigation of a method using a laser beam of 20 to 410 nm is in progress.

Also, attempts have been made to intervene with an auxiliary layer having a super-resolution effect in which the transmittance and the focusing radius change non-linearly with respect to the laser beam intensity, and a focused spot having a size smaller than the diffraction limit is obtained. ing.

JP-A-8-96412 discloses a super-resolution effect using a phthalocyanine-based organic film or a chalcogenide-based inorganic film. JP-A-6-162564 discloses an example using a thermochromic material. Kaihei 6-267078
The publication discloses an example using a photochromic material. All of these studies examined how to achieve even higher recording density depending on how small a laser beam of a single wavelength can be focused to a small spot diameter.

As a means for further improving the recording density, a method of devising the shapes of the recording grooves and recording bits has been proposed (Japanese Patent Laid-Open No. 11-16215).

According to this, the inclination angle of the recording surface whose recording track has an inverted V-shaped cross section in the radial direction of the optical disk is 4 °.
It has a pair of inclined recording ridges of 5 degrees. In this manner, information is recorded on each surface, but a method of simultaneously reading binary information by irradiating the entire recording groove width with a laser beam at the time of reading is described.

However, according to this method, it is necessary to form a recording layer having a variable reflectivity on the recording ridge, and to bury the recording ridge itself by 3/4 wavelength from the surface of the optical disk. It is not easy to manufacture the optical disk itself because it is necessary to form the same high-reflectance thin film layer on the surface of the optical disk.

Further, even when the entire surface is covered with the same recording layer, recording is simultaneously performed on the vertical side surfaces of the groove at the time of recording, and there has been a difficulty that a desired reflectance cannot be obtained.

Further, since the recording grooves themselves are formed continuously and in a spiral shape, it is difficult to distinguish between the positioning guide grooves and the recording grooves on a normal optical disk, and the recording ridge is located above the surface of the optical disk. Since it is inside, the laser spot condensed to the diffraction limit cannot be condensed on each recording surface with the minimum size, so that light always enters perpendicular to the substrate surface. Occasionally, recording unevenness occurs, and the optical power density decreases. Therefore, there is a problem that writing with higher output is required.

As described above, the recording density of an optical disk is determined by its spot diameter, but several methods have been proposed in order to achieve higher-density recording.

For example, photochemical hole burning (Photoc
In the Chemical Hole Burning (PHB) method, when a laser beam having a narrow wavelength band is irradiated at a very low temperature in an absorption band at a specific wavelength range, it is called a hole on the absorption spectrum corresponding to the wavelength. Utilize the phenomenon of bleaching. When holes are successively opened at different wavelengths using a wavelength variable laser, a lot of bit information is recorded in one spot. This is said to enable multiplex recording of 1000 times or more.

However, so far, the PHB phenomenon occurs only at the liquid helium temperature or at most the liquid nitrogen temperature, and when the temperature rises, the formed holes disappear or the multiplicity actually observed is about 100. However, there is a problem that there is no threshold value for reading by the reproduction light, and the signal is deteriorated.

[0040]

As described above, the main guideline for high-density recording of an optical disk is to focus the spot size to the diffraction limit using a laser having a short wavelength as much as possible. Although the use of a material having a multiple recording property as the material of a part of the recording layer is also being studied, it is not practical. In particular,
When looking back on the structure of an optical disk actually used and the method of detection, if a very high density can be achieved by means as simple as possible, a great industrial advantage can be obtained.

An object of the present invention is to provide a laser having a spot size narrowed down to the diffraction limit, an optical information recording medium capable of performing multiplex recording in one layer without using a special multiplex recording material, and an optical information recording medium using the same. An optical recording / reproducing apparatus is provided.

[0042]

The gist of the present invention for solving the above-mentioned object is as follows.

[1] Light having a substrate and a recording film for writing or reading information by changing the reflectivity, transmittance or intensity distribution of incident light formed directly or via another layer on the substrate. A guide groove for specifying a position on a substrate for writing or reading information on an information recording medium; and two guide grooves formed along the guide groove and having a predetermined angle with the substrate to record information. An optical information recording medium, wherein a plurality of recording ridges having the above-described surfaces are formed, and the recording ridges are provided at predetermined intervals.

[2] The optical information recording medium described above, wherein two or more recording surfaces forming the recording ridge can record independent information on each surface.

[3] One surface area of the recording line is
The above-mentioned optical information recording medium having a size of 1/10 or more of a beam spot capable of optically condensing incident light for recording or reading information.

[4] The optical information recording medium as described above, wherein information pits for determining a track position are formed in the recording ridge or outside the recording ridge.

[5] The optical information recording medium has a reflective layer,
The optical information recording medium described above, which is configured to determine whether or not information is written based on a difference in surface roughness of the reflective layer.

[6] A laser source of a plurality of wavelengths for irradiating the optical information recording medium according to any one of [1] to [5] for writing or reading information, and a selection means for selecting the laser A focus adjusting means for adjusting a focal point which changes for each laser; and a discriminating means for discriminating the recording capacity of the optical information recording medium, and performing tracking in accordance with the recording capacity of the optical recording medium discriminated by the discriminating means. An optical recording / reproducing apparatus having tracking changing means for changing.

[7] A plurality of recordings wherein incident light for recording or reading information is formed in the recording ridge at one time on the recording ridge of the optical information recording medium according to any one of [1] to [5]. The above-mentioned optical recording / reproducing apparatus configured to be capable of recording or reading by irradiating a part or all of the spot.

[8] A method for writing or reading information by using reflected light or transmitted light from a guide groove formed outside the recording layer of the optical information recording medium according to any one of [1] to [5]. The above-mentioned optical recording / reproducing apparatus configured to adjust a laser irradiation position and its focus.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate in the optical information recording medium of the present invention includes inorganic glass such as borosilicate glass and quartz glass, polycarbonate, polymethyl methacrylate, polystyrene, polyacrylic acid, polyimide, epoxy resin and the like. Organic polymer and the like can be used.

Examples of the material for the recording layer in the optical information recording medium include a selenium / tellurium alloy, an antimony selenide / bismuth telluride multilayer film, an antimony / selenium / tellurium amorphous alloy, terbium / iron / cobalt Alloys, terbium, iron, cobalt alloys / terbium, deuterium,
Iron / cobalt alloy two-layer film, germanium / antimony / tellurium / cobalt alloy, bismuth / antimony sulfide /
inorganic compounds such as n-hexatriacontane three-layer film,
Organic compounds such as a spiropyran dye, a platinum bis (dithio-α-diketone) complex, a squarylium dye, a rhodamine dye, a naphthoquinone dye, an azulenium dye, a cyanine dye, a phthalocyanine, and a naphthalocyanine can be used.

As a material for the reflective layer in the optical information recording medium, a metal material such as aluminum, silver, gold, nickel or the like can be used. In the optical information recording medium, various nonlinear optical materials capable of changing the transmittance, the reflectance, and the refractive index by the incident light itself, for example, metal phthalocyanine, metal naphthalocyanine, anthracene,
It is also possible to provide another layer containing dinaphthalocyanine, chalcogenide glass, cadmium selenide, zinc selenide, cobalt oxide, antimony, erbium, or the like.

Means for forming the substrate of the present invention include cutting and polishing from a base material, photopolymerization, thermal polymerization in a mold,
Methods such as a polymer stretched thin film forming method and a melt injection molding method can be used.

Means for forming a thin film such as a recording layer and a reflective layer formed on a substrate include a spin coating method, a casting method, a roll coating method, a pulling method, a water surface spreading method, a Langmuir-Blodget method, Methods such as an electrolytic polymerization method, a vacuum evaporation method, a sputtering method, a molecular beam evaporation method, a plasma polymerization method, a sol-gel method, and an ion cluster beam method can be used.

As means for forming the recording ridges and guide grooves of the present invention, various precision processing techniques, for example, precision diamond cutting, laser processing, etching, photolithography, reactive ion etching, focused ion beam etching , Dicing or the like can be used.

The optical information recording medium of the present invention may be subjected to a process for improving the appearance and characteristics and extending the life after forming the product. Such post-processing includes thermal annealing, radiation irradiation, electron beam irradiation, light irradiation, radio wave irradiation, magnetic force line irradiation,
Ultrasonic irradiation and the like can be mentioned.

Further, the optical information recording medium is variously compounded,
For example, bonding a plurality of optical information recording media using a means depending on the use or purpose, such as adhesion, fusion, electrodeposition, vapor deposition, pressure bonding, dyeing, melt molding, kneading, press molding, coating, etc. It is possible to make a composite such as bonding and attaching a protective film.

As a light source for writing or reading information on or from the optical information recording medium of the present invention, GaAlAs
Semiconductor lasers such as GaN, ZnSe, etc., Ar
And various lasers such as solid lasers such as titanium sapphire and ruby, and various types of wavelength conversion elements such as lithium niobate, barium borate, and potassium triphosphate. A light source or the like with a changed wavelength can be used.

In particular, as a light source for writing information to the read-only optical information recording medium, various lasers in the ultraviolet or X-ray region, electron beams, metal ion beams such as gallium, and the like can be used.

The optical recording / reproducing apparatus using the optical information recording medium of the present invention includes various control devices such as an optical information recording medium rotating mechanism, a medium discriminating mechanism, an information pickup device, a tracking error detecting and correcting means, and a laser. Light sources and controllers, recording and readout information conversion electronics, address readout determination mechanisms, signal synchronization means, laser focusing and separation or wavelength selection mechanisms, photodetectors and two-dimensional photodetector array means can be incorporated.

Alternatively, as various application devices incorporating the optical recording / reproducing device of the present invention, for example, a compact disk (CD), video disk (VD), magneto-optical disk (MO), CD-R, CD-ROM, DVD- ROM,
DVD-RAM and the like can be mentioned.

Also, there can be mentioned various systems such as an audio system, a video recorder, a recording device for a computer, a server for information communication, a router for a network and the like using these various applied devices.

According to the present invention, in a conventional optical information recording medium and an optical recording / reproducing apparatus using the same, even if a laser light source of a specific wavelength which defines a limit of a recording density is used,
Due to a recording ridge having multiple reflection surfaces in a region below the diffraction limit, light perpendicularly incident on each spot is simultaneously reflected in different directions.

By two-dimensionally detecting the reflected light in the different directions, higher-density reading can be performed. By irradiating each surface with a laser beam from multiple directions that can follow the opposite optical path for writing and recording and writing only on a specific surface, it is possible to write multiple spots in the diffraction limited area In addition, the recording density can be improved.

Next, an optical information recording medium according to the present invention and an optical recording / reproducing apparatus using the same will be described based on embodiments.

[Embodiment 1] First, the basic configuration of the optical information recording medium of the present invention will be described. FIG. 1 shows a partial structure of an optical disk comprising the optical information recording medium of the present invention.

Normally, an optical disc has a guide groove 3 formed on an optical disc substrate 1 for scanning a laser beam spot for writing or reading, and optical recording is performed on the guide groove or between adjacent guide grooves. A spot is formed.

The most basic structure of the present invention is that an uneven surface called a recording ridge 2 is formed on the guide groove 3 in advance. The size of the recording ridges 2 is approximately equal to the diffraction limit of the laser beam to be used, and the recording ridges 2 are arranged along the guide grooves 3 with an interval of such a size, whereby a plurality of recording ridges 2 are arranged.

Here, as one example, FIG. 2 shows a structure of a recording ridge comprising two ridges. Here, a two-sided cross section in which two planes having a length a and a width b are combined at an angle φ with respect to the optical disk surface and the upper surface structure thereof are shown.

A two-sided ridge having such a shape is formed on the surface of the substrate 4 when the substrate 4 is formed, and the recording film 5 is laminated thereon.
A reflective layer 6 is formed thereon, and a protective layer 7 is formed on the surface.

Writing and reading of information pits are performed as follows.
This is performed by making a laser beam incident from the substrate 4 side.

Here, it is assumed that the spot diameter of the laser beam is narrowed down to the diffraction limit, and the length a or bcos φ is about the beam spot d. In the plan view, there are four recording edges 8, 8 ', 8'',
8 '''shows the arrangement relationship. For the guide groove direction,
Here, such recording ridges are arranged by the same length a, and the distance between the recording ridges on the adjacent guide grooves 9, 9 'is c.

Next, the incidence of light on this optical information recording medium,
The relationship of reflection will be described with reference to FIG. Due to the rotation of the optical disk, the laser beam is scanned and irradiated along the guide groove,
For example, when the optical disk is irradiated with a laser beam perpendicularly and information is detected by the reflected light from the reflective layer 6, the reflection angle of the reflected light is significantly different between the recording ridge and the outside of the recording ridge therebetween.

FIG. 3 shows a laser beam having a spot diameter D with respect to such a reflecting surface, which is condensed by a condensing lens 10 to obtain a condensing spot diameter d and a focal length f. The path of the incident light when irradiating the outside 11 is indicated by a, and the path of the reflected light is indicated by b. The path of the reflected light is indicated by d (only the reflecting surface is shown here for simplicity). Assuming that the irradiated laser is a parallel Gaussian beam, the wavelength of the light is λ, and the numerical aperture of the condenser lens is NA,

[0076]

D = 2 × 0.41λ / NA (1) NA = sin θ = W / √ (W ² + f ² ) (2) where W = D / 2.

Here, the center of the spot scans the apex of the two ridges according to the guide groove. When the light is applied to the outside of the recording area, the reflected light follows the same path as it is and is specularly reflected. However, the laser beam applied to the recording surface is reflected off the side at a reflection angle φ since the reflection surface is not parallel to the substrate.

In this case, since the recording ridge having two ridges is used, the reflected light travels through two paths R1 and R2. Conversely, when the laser is applied along these two paths, the laser light can be applied to each of the two ridges, whereby information pits can be written on the specific surface. At this time, the size of the recording ridge (length a or bsinφ in FIG. 3) is desirably equal to or smaller than the converging spot in consideration of the displacement of the laser beam (otherwise, only one surface can be irradiated). It is desirable that the area of the recording area is at least 1/10 of the spot size.

Since the reflectance is different on the surface on which the information is written, the information can be reproduced by detecting the reflected light on the paths R1 and R2 at the time of reading.

Further, reflected light is obtained vertically outside the recording area, and the tracking position can be corrected using the light.
That is, by detecting the specular reflection light and the oblique reflection light at different positions, it is possible to distinguish the positioning and the reflection light for reading the information.

Next, an example of an optical system of a write-once type information recording / reproducing apparatus for an optical information recording medium of the present invention having a recording ridge having two surfaces will be described with reference to FIG.

An optical system for writing information, an optical system for reading information, and an optical system for determining a tracking position are integrated with the optical information recording medium 13 of the present invention. .

At the time of normal information reproduction, light emitted from the reading laser 19 is collimated by the lens 18, reflected by the half mirror 17, reflected by the mirror 16, passes through the hole of the concave mirror 15 with holes, and is collected. The light is condensed by the optical lens 14 and is applied to the recording edge or the outside of the recording edge of the optical information recording medium as shown in FIG.

The specularly reflected light outside the recording ridge or due to a slight displacement of the recording ridge follows the same optical path, passes through the condenser lens 14, passes through the hole of the concave mirror 15 with a hole, and is reflected by the mirror 16. , Passes through a half mirror, is gradually condensed by a lens 20, and is divided into two by another half mirror 21.

The transmitted specularly reflected light passes through the cylindrical lens 22 and enters the focusing light meter 23, and the tracking position is corrected by analyzing the light amount. Another specular reflection light enters a pure specular reflection light meter 24 and measures the specular reflection light amount.

Since the laser beam applied to the recording surface is obliquely reflected on two paths as described with reference to FIG. 3, it follows a reflection path different from the regular reflection, passes through the condenser lens 14, and
The light reaches the concave mirror 15 with a hole, but cannot pass through the hole due to the oblique reflection, and is reflected by the concave mirror beside the hole.

Here, it is desirable that the reflected light spread by oblique reflection is again collimated by a concave mirror. The two obliquely reflected lights reflected by the concave mirror with holes 15 pass through the half mirror 25 and are detected by the oblique reflected light meters 26 and 26 ', respectively. This light amount corresponds to the written information.

The half mirror 25 reflects a part of the obliquely reflected light.
When the 7 'and the writing lasers 28, 28' are arranged,
With the writing lasers 28 and 28 ', laser irradiation can be performed only on a specific surface of the recording surface, thereby forming an information spot.

FIG. 5 shows the detection characteristics when optical information is detected by focusing a laser beam on an optical recording medium having such a recording edge.

For the recording ridges 29, 29 ', 29 ", and 29'" having four two-sided ridges on one guide groove, specular reflected light and oblique reflected light when the reading light focusing spot 30 is scanned. The magnitude of the detected light amount of the light R1 and the other obliquely reflected light R2 is displayed based on the scanning position of the condensed spot.

When the condensed spot is sequentially scanned, specular reflected light is strong outside the recording area, and oblique reflected light is not detected.
However, when the spot hits the recording ridge, the specular reflection light decreases and the oblique reflection light increases. When the spot completely hits the recording ridge, the amount of the oblique reflection light becomes maximum. When the spot begins to deviate from the recording edge, the amount of obliquely reflected light decreases in the reverse order, and the amount of specularly reflected light increases.

As described above, the specularly reflected light and the two obliquely reflected lights are detected by the independent light meters, and the detection time characteristic differs depending on the spot detection position.

Therefore, by using the specular reflection light for tracking position correction and tracking address detection, information recorded in the recording area can always be detected accurately.

[Embodiment 2] Next, a description will be given of light detection characteristics expected when the optical information recording medium of the present invention having a recording layer having another geometric structure is used.

FIG. 6 shows examples of recording ridges of various shapes including the recording ridge shown in the first embodiment.

FIG. 6A shows a recording ridge having two ridges shown in the first embodiment. The method of writing and reading information on and from the optical information recording medium having this recording ridge will be described in the embodiment. As you did.

It is possible to change the arrangement direction with respect to the guide groove even in the recording ridge having the same two-sided ridge. As an example, the ridge is arranged so that the top side of the two-sided ridge is perpendicular to the guide groove. FIG. 6 (b). With such an arrangement, the direction in which the obliquely reflected light from the recording ridge is detected is determined according to the first embodiment.
By correcting the position to a position different from the above, it is possible to record and reproduce information by exactly the same means.

FIG. 7 shows a pattern of the detected light amounts of the regular reflection light and the two oblique reflection lights when a plurality of such recording ridges are arranged.

Along the guide groove direction, four recording ridges 31,
31 ′, 31 ″, and 31 ″ ″, and the relationship between the detected light amounts when the light condensing spot 32 is sequentially scanned is shown.

Since the detection positions of the specular reflection and the oblique reflection are different, not only can they be detected by completely different detectors, but also their signal detection timings are shifted by a fixed relationship. Also, here, a typical pattern in which recording ridges are arranged at equal intervals is shown, but it is not always necessary to alternately arrange the recording ridges and the outside of the recording ridges. Alternatively, depending on the size of the sector of the address pattern, after a flat surface outside the recording ridge continues for a certain length, a plurality of recording ridges may be continuously arranged without sandwiching the recording ridge outside.

In this case, the recording ridges are also clogged up to the outside of the recording ridges, so that the recording density can be further increased. However, the detection position of the information is different between the two oblique reflections. Since the reading is repeated alternately, the reading error does not change.

FIG. 6 shows an example of a recording ridge having another shape.
A recording ridge composed of four ridges as shown in FIG.

In this case, just as shown in FIGS.
And the detection direction is (a)
And (b). In this case, it is possible to write information four times as large as that of the conventional one in one recording area, and it is possible to further improve the recording density.

FIG. 6D shows a case in which the arrangement angle of the recording ridge shown in FIG. 6C is changed so that the top of the recording ridge is parallel to the guide groove. A similar function can be achieved by changing from (c).

FIG. 6 (e) is a view in which a part of the vertex of the recording ridge shown in FIG. 6 (c) is flattened. Thus, the irradiation position of the beam can be monitored. As described above, it is possible to perform higher-density recording by using recording ridges of various shapes.

As described above, the recording density can be improved by forming a multi-sided shape, but if there are too many surfaces, the crosstalk of the reflected light from the adjacent surface is increased. Depends on the accuracy of the available optical system.

In addition, since the size of one reflecting surface is reduced by the multi-plane, dynamic optical writing such as a write-once or rewritable optical disk may be difficult.

However, only writing on the master is performed using a short wavelength light source such as ultraviolet rays or X-rays having a sufficiently high resolution, an electron beam, a particle beam, or the like. It can be used as a high density recording optical disk.

At the time of reproduction, instead of preparing detectors for obliquely reflected light as many as the number of faces, a two-dimensional photodetector such as a CCD camera performs collective reading as a two-dimensional pattern of reflected light, thereby achieving high-speed reading. Reading is also possible.

Here, information is written in the recording area,
Although the case where the outside of the recording ridge is used for tracking positioning, sector address, etc. has been described, conversely, it is also possible to place sector information on the recording ridge portion or to perform positioning based on the amount of reflected light from each surface of the recording ridge. it can.
In this case, it is possible to further reduce the outside of the recording area.

Although the recording ridges illustrated in FIG. 6 are all formed in a convex shape with respect to the paper surface, they may be formed with a concave shape with respect to the paper surface.

[Embodiment 3] Next, a description will be given of an example in which the reflection effect from the recording edge is confirmed by a laser beam focused to the diffraction limit in a more specific configuration.

The minimum basic structure of the present invention is a recording ridge formed by a plane at an angle different from the optical disk surface.

Therefore, in order to confirm the principle of optical recording on such a surface and the reflection characteristics from the surface, a model recording ridge is formed, and when a laser spot is scanned from the outside of the recording ridge to the recording ridge. Light reflection characteristics were detected, and oblique reflection in different directions was confirmed. The substrate on which the recording ridge to be used as a sample was formed was prepared in the following procedure.

A p-type dove silicon single crystal wafer (single-sided optical polishing, (100) plane, off-angle, manufactured by Shin-Etsu Chemical Co., Ltd.) is prepared, and a focused ion beam etching apparatus (FB-2000, manufactured by Hitachi, Ltd.) is provided on the optically polished surface. The substrate was dry-etched obliquely at a tilt angle φ = 30 degrees, a length a = 10 μm, and a width b = 5 μm.

The working is performed by medium finishing, and the flatness of the worked surface is about 10 nm. This is a shape in which just one of the two recording surfaces of the first embodiment is applied.

Next, a molecular beam deposition apparatus (manufactured by Nidec Anelva,
IMBE-620), aluminum
The entire surface of the substrate was made a mirror surface. This was used as a sample for confirming the principle, and its reflection characteristics were confirmed by the optical system shown in FIG. The configuration will be described below.

As a reading light source, a He-Ne laser (manufactured by Meles Griot, wavelength 633 nm) 33 was used. The beam diameter is 1 mm.
4 expanded the beam diameter to 5 mm.

This is guided toward the measuring section by the mirror 35, passes through the half mirror 37, and is condensed (NA = 0.5).
3) The light was condensed at 38, and a beam spot of about 1 μm was formed at the focal point. In the vicinity of the focal point, the prepared sample 39 is mounted on a fixed piezo stage (Nanotrac made by Meles Griot).

The reflected light from the sample mirror surface passes through the condenser lens 38 again, is reflected by the half mirror 37, and
The reflection pattern is detected by a CD camera (C2741 manufactured by Hamamatsu Photonics). At this time, three irises 36, 36 ', 36''are arranged to adjust the optical system.
After performing collimation of the entire optical system using the regular reflection surface, the iris is stopped down, the sample is adjusted to the focal position in the z direction, and the sample is scanned in the x-axis direction within that surface, and the recording portion is processed. The end was positioned, and this was set as the position of x = 0 μm.

After the arrangement of the sample and the like is determined as described above,
The sample was moved to a position shifted by 10 μm toward the specular reflection surface side in the x-axis direction, and the reflected light was detected by fully opening the iris while moving the sample to the recording side by 0.2 μm.

At first, the Gaussian beam intensity pattern had a beam diameter of 5 μm. From x = 0 μm, a second peak appeared at a position shifted by 4 mm from the peak position of the beam intensity at the detection position of the CCD camera. Further, when the sample is moved, the first peak intensity decreases and the second peak intensity increases over x = 1 μm, and thereafter, while moving to x = 4 μm, the second peak has only one maximum intensity position. It became.

That is, when a laser beam narrowed to the diffraction limit is scanned in the vicinity of such a recording ridge, the reflection surface having two inclinations of the recording ridge and the outside of the recording ridge just within the area of the beam spot is obtained. The reflected light from was observed.

[Embodiment 4] Next, an example of a system configuration of an optical recording / reproducing apparatus using the optical information recording medium of the present invention will be described.

FIG. 9 is a block diagram showing the system configuration of the optical information recording / reproducing apparatus used in this embodiment. It has a medium discriminating means for discriminating the type of an optical disc as an optical recording medium.

The optical disk is temporarily fixed to a rotating mechanism directly or indirectly connected to the rotating shaft of the motor controlled by the motor circuit control means. The information on the optical disk is read as an optical signal by a laser as a light source in the pickup and a detecting unit for detecting reflected light. Also, information is stored on the optical disk by the light source in the pickup.

The optical signal passes through the preamplifier, the read signal processing means, the address reading means, the clock synchronization signal reading means, and is output to the outside of the apparatus by the reproduction data transmission means via the reproduction signal demodulation means. The reproduced data is output by a predetermined output unit such as a display device or a speaker, or data processing is performed by an information processing device such as a personal computer.

In this embodiment, in addition to the circuit system used for normal recording and reproduction, a laser selecting means capable of selecting an arbitrary laser wavelength is provided. Based on the output of the laser selecting means, the analysis of the laser power control information analyzing means is performed, and the peak power used by the peak power determining means is determined.

The output of the peak power determining means is supplied to the recording power DC amplifier and the erasing power D via the power ratio determining means.
The signal is input to the laser driver via the C amplifier and controls the light source in the pickup. Similarly, read power DC
The output of the read power determining means is input to the laser driver via the amplifier, and controls the light source in the pickup.

As an actual laser, a semiconductor laser of 780 nm used for CD, 650 nm used for DVD, 520 nm, 410 nm can be mounted.

Since the focal point and the depth of focus are different depending on the wavelength, an auto-focusing structure is adopted according to the selection of the laser. Further, the tracking error detecting means can perform tracking according to the disk medium. In addition, a medium type discriminating mechanism is provided by utilizing the difference in the reflectance of the medium, so that auto-tracking according to the difference in the medium type is designed.

At the time of data recording, recording data is input from the recording data receiving means, data is modulated by the recording data modulating means, and is input to the laser driver via the recording timing correcting means to control the light source in the pickup.

By adopting the system configuration as shown in FIG. 9, not only can it be used with conventional optical information recording media such as CDs and DVDs, but also disks having different recording capacities due to increased capacity can be used as one device. It can be handled with.

The purpose of the optical information recording / reproducing apparatus is to
Depending on the application and the like, the configuration may be appropriately changed and used.

[Embodiment 5] Next, an example of the use of an optical recording / reproducing apparatus using the optical information recording medium of the present invention is shown in FIG.
This will be described with reference to FIG.

As shown in FIG. 10A, an optical disk cassette 43 having a predetermined shape is inserted into a DVD drive 42 having a built-in optical information recording / reproducing mechanism as described in the fourth embodiment. The information recording medium 44 is mounted.

As shown in FIG. 10 (b), the optical information recording medium 44 itself is installed inside the optical disk cassette 43 '. Usually, the optical information recording medium 44 is externally provided by a plastic housing of the optical disk cassette and an aluminum cover. The optical information recording medium itself does not come into direct contact with the optical information recording medium.

Then, only when inserted into the DVD drive, the aluminum cover is opened, and light can be input / output to / from the optical information recording medium. Therefore, the structure is such that the user can appropriately exchange the necessary optical information recording medium without directly touching the optical information recording medium itself.

Further, since the recording spot is small, the recording spot may be gradually contaminated by dust or dirt.
It is also possible to have a surface cleaning function.

Further, what is shown here is an example of the use form of the optical recording / reproducing apparatus using the optical information recording medium of the present invention, and the surface contamination is not significantly considered depending on the difference in the material of the optical disk and the like. Without optical disc cassette
It is also possible to directly insert and remove the DVD drive. Such a DVD drive itself can be used alone to be used for a video or audio playback device, and can also be incorporated in other electrical equipment, for example, a personal computer body.

[0141]

According to the present invention, a novel optical information recording medium and an optical recording / reproducing apparatus using the same can be obtained.

When the optical information recording medium of the present invention and the optical recording / reproducing apparatus using the same are used, it is possible to record a multiple of the number of recording polyhedrons per one light irradiation area, thereby improving the recording density. . Also, to use a single wavelength light source,
The optical system is simple.

Further, when the laser is scanned along one guide groove, the recording ridge and the outside of the recording ridge are alternately arranged, so that the recording portion and the positioning portion are alternately detected, and the recording signal is always set to zero once. Since return-to-zero detection can be performed and position correction can be performed, it is possible to improve detection sensitivity and reduce read errors.

Further, by recording finer information in an area below the diffraction limit, higher density recording can be achieved.

Since information written in one recording layer can be reproduced by one laser scan, high-speed reproduction is possible despite high-density recording.

Further, by using the outside of the recording area as the focal point position correction and the track address, an optical information recording medium with a small reading error and an optical recording / reproducing apparatus using the same can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic structure near a recording edge of an optical information recording medium of the present invention.

FIG. 2 is a schematic diagram of a cross section and a top structure of a recording ridge having two ridges of the optical information recording medium of the present invention.

FIG. 3 is a diagram showing the relationship between light input and output to an optical information recording medium having a recording surface having two ridges on the optical information recording medium of the present invention.

FIG. 4 is a schematic diagram showing a pickup optical system of an optical recording / reproducing apparatus for performing information writing, reading, positioning, and the like on an optical information recording medium having a recording edge having two edges of the optical information recording medium of the present invention. is there.

FIG. 5 is a diagram showing a relative relationship between a change in the amount of specular reflection and a change in two obliquely reflected light amounts during scanning of a laser spot in the guide groove direction of an optical information recording medium having a recording ridge having two ridges according to the present invention. .

FIG. 6 is a schematic perspective view showing examples of recording tracks of various shapes of the optical information recording medium of the present invention.

FIG. 7 is a diagram showing a relative relationship between changes in the amounts of light of regular reflection and two oblique reflections at the time of laser spot scanning in the guide groove direction of the optical information recording medium having the recording ridge having the shape of FIG. 6B. is there.

FIG. 8 is an arrangement diagram of an optical system for confirming a recording edge of the optical information recording medium of the present invention and a reflection characteristic of a laser spot from outside the recording edge.

FIG. 9 is a block diagram showing a system configuration of an element, a control unit, and the like constituting an optical recording / reproducing apparatus using the optical information recording medium of the present invention.

FIG. 10 is a schematic perspective view showing an example of a use form of an optical recording / reproducing apparatus using the optical information recording medium of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk board, 2 ... Recording groove, 3 ... Guide groove, 4 ... Substrate, 5 ... Recording layer, 6 ... Reflective layer, 7 ... Protective layer, 8 ... Recording groove, 9 ... Guide groove, 10 ... Condensing lens, DESCRIPTION OF SYMBOLS 11 ... Outside of recording area, 12 ... Recording area, 13 ... Optical information recording medium, 14 ... Condensing lens, 15 ... Concave mirror with hole, 16 ... Mirror, 17 ... Half mirror, 18 ... Lens, 19 ... Reading laser, 2
0: lens, 21: lens, 22: cylindrical lens, 23:
Focusing light meter, 24: regular reflection light meter, 25: half mirror, 26: oblique reflection light meter, 27: lens, 28
… Writing laser, 29… recording spot, 30… read light focusing spot, 31… recording spot, 32… read light focusing spot, 33… He-Ne laser, 34… collimator lens, 35… mirror, 36… iris 37, half mirror, 38, condensing lens, 39, sample, 40, piezo stage, 41, CCD camera, 42, DVD drive,
43 ... optical disk cassette, 44 ... optical information recording medium.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 7/007 G11B 7/007 7/09 7/09 BCF term (Reference) 5D029 JB11 WA20 WA21 WA31 WA35 WB01 WC03 WC07 WD10 5D090 AA01 BB03 BB15 CC06 CC14 DD02 FF02 FF13 GG11 GG22 KK06 KK12 KK14 5D118 AA11 BA01 BB01 BB02 BC09 BC10 BC17 BD01 BF02 BF03 CC12 CD02 CD03 CG03 CG07 CG26 CG29 CG29 CG29

Claims (8)

[Claims] 1. Optical information comprising a substrate and a recording film for writing or reading information by changing the reflectance, transmittance or intensity distribution of incident light formed directly or via another layer on the substrate. In a recording medium, a guide groove for specifying a position on a substrate for writing or reading information, and two or more recording grooves formed along the guide groove and having a predetermined angle with the substrate to record information An optical information recording medium characterized in that a plurality of recording ridges having the same surface are formed, and the recording ridges are provided at predetermined intervals. 2. The optical information recording medium according to claim 1, wherein two or more recording surfaces forming the recording ridge are configured to record information independently on each surface. 3. The recording surface according to claim 1, wherein one surface area of the recording area is at least 1/10 of a beam spot capable of optically condensing incident light for recording or reading information. Optical information recording medium. 4. The optical information recording medium according to claim 1, wherein information pits for determining a track position are formed on the recording ridge or outside the recording ridge. 5. The optical information recording medium according to claim 1, wherein the optical information recording medium has a reflective layer, and whether or not information is written can be determined based on a difference in surface roughness of the reflective layer. Optical information recording medium. 6. A laser source of a plurality of wavelengths for irradiating the optical information recording medium according to claim 1 for writing or reading information, a selecting means for selecting said laser, A focus adjusting means for adjusting a focal point which changes for each laser; and a discriminating means for discriminating the recording capacity of the optical information recording medium, wherein a tracking change for changing the tracking according to the recording capacity of the optical recording medium discriminated by the discriminating means. An optical recording / reproducing apparatus characterized by comprising means. 7. An optical information recording medium according to claim 1, wherein incident light for recording or reading information is formed on a plurality of recording spots formed in the recording edge at one time. The optical recording / reproducing apparatus according to claim 6, wherein the optical recording / reproducing apparatus is configured to be capable of recording or reading by irradiating a part or the whole. 8. A laser irradiation position for writing or reading information by reflected light or transmitted light from a guide groove formed outside a recording edge of the optical information recording medium according to claim 1. 7. The optical recording / reproducing apparatus according to claim 6, wherein said optical recording / reproducing apparatus is configured to be able to adjust its focus.