JP2000011453A - Optical recording medium and optical recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium consisting of an optical disk which is capable of making its storage capacity to >=8 GB and has a ROM(Read.Only.Memory) in at least part as basic constitution. SOLUTION: A light transparent layer 12 is formed on an information recording surface 11 formed with information recording pits and is irradiated with the laser beam of 380 nm<=λ<=450 nm in wavelength λ through a lens system of >=0.76 in N.A(numerical aperture) from the light transparent layer side, by which the reading out of the information is executed. The thickness (t) of the light transparent layer is specified 3 to 182 μm and the thickness unevenness Δt thereof to within ±5.26 λ/(N.A)4 in the region of a signal information section. The track pitch TP on the information recording surface 11 is specified to 0.27 to 0.404 μm, the shortest pit length Pmin of information recording pits to 0.13 to 0.219 μm, the recording linear density LD to a bit string of >=0.146 μm/bit and the depth D of the information recording pits to 0.14 to 0.219 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium and an optical recording / reproducing apparatus (the optical recording / reproducing apparatus in this specification refers to an apparatus for optically reproducing and / or recording on an optical recording medium). ), In particular, to achieve a large recording capacity using a blue wavelength range and blue and red laser beams.

[0002]

2. Description of the Related Art A disk-type optical recording medium has the advantages of a high-speed access, a small-sized and simple recording / reproducing apparatus. To realize a disk that can be replaced with a current video tape recorder (VTR), a storage capacity of 8 GB (gigabyte) or more is required.

[0003]

SUMMARY OF THE INVENTION According to the present invention, there is provided an optical recording system comprising an optical disk having a ROM (Read Only Memory) part at least in part, the storage capacity of which can be made 8 GB or more. It is a main object of the present invention to provide a medium and an optical recording / reproducing apparatus that performs reproduction and / or recording on the optical recording medium.

[0004]

In an optical recording medium according to the present invention, a light transmitting layer is formed on an information recording surface on which information recording pits are formed, and a wavelength λ is 380 from the light transmitting layer side.
A laser beam having a wavelength of nm ≦ λ ≦ 450 nm is applied to A. The information is read out by irradiating through a lens system having a (numerical aperture) of 0.76 or more, and the thickness of the light transmitting layer is set to 3 μm to
182 μm, and the thickness unevenness of the light transmitting layer is ± 5.26λ.
/ (NA) within ⁴ and track pitch 0.2
7 μm to 0.404 μm, the shortest pit length of the information recording pits is 0.13 μm to 0.219 μm, and the recording linear density is a pit row of 0.146 μm / bit or less.
The recording pit has a depth of 31 nm to 75 nm.

An optical recording / reproducing apparatus according to the present invention uses the above-described optical recording medium according to the present invention and has a wavelength λ of 3
A laser beam having a wavelength of 80 nm ≦ λ ≦ 450 nm was applied to N.I. A. Has a configuration in which a laser beam is incident on the optical recording medium from the side of the light transmitting layer through an optical system of 0.76 or more to reproduce recorded information on the information recording surface.

Further, in the optical recording medium according to the present invention, a light transmitting layer is formed on the information recording surface, and a laser beam is irradiated from the light transmitting layer side, and the information recording surface has at least one or more first and second information recording surfaces. The first information recording surface and the second information recording surface are each laminated via an intermediate layer of a light transmitting layer. The sum of the thicknesses of the light transmitting layer and the intermediate layer interposed between the information recording surface and the laser light incident surface is 3 μm to 1 μm.
It is 82 μm. That is, when only the light transmitting layer is interposed between the information recording surface and the laser light incident surface, the thickness is set to 3 μm to 182 μm, and when the light transmitting layer and the intermediate layer are interposed, Sum of thickness of 3μm
１８182 μm. The thickness unevenness between the incident surface and all the information storage layers is set within ± 5.26λ / (NA) ⁴ . The track pitch of the first information recording surface is 0.27 μm to 0.404 μm, and the track pitch of the second information recording surface is 0.45 μm to 0.57 μm.
m. Then, with respect to the first information recording surface, the wavelength λ
Emits a laser beam having a wavelength of 380 nm ≦ λ ≦ 450 nm.
A. Irradiation through an optical system with (numerical aperture) 0.76 or more,
The wavelength λ is 635 nm ≦ λ ≦ with respect to the second information recording surface.
680 nm laser light was applied to A. (Numerical aperture) 0.7
Irradiation is performed through six or more optical systems to perform at least one of recording and reproduction.

Further, an optical recording / reproducing apparatus according to the present invention uses an optical recording medium having the above-mentioned first and second information recording surfaces, and uses a first laser beam having a wavelength λ of 380 nm ≦ λ ≦ 450 nm; The wavelength λ is 635 nm ≦ λ ≦ 680
nm second laser light, respectively. A. (Numerical aperture) through the optical system of 0.76 or more,
The information recording surface and the second information recording surface are irradiated to perform at least one of recording and reproduction.

With the above-described configuration, a large storage capacity of 8 GB or more can be realized.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an optical recording medium according to the present invention is shown in FIG.
The light transmitting layer 12 is formed on the information recording surface 11A in which the information recording pits 13 are formed on one surface.

The substrate 10 is made of, for example, polycarbonate (P
C) is formed by injection molding, and at the same time as the molding, the fine irregularities of the required pattern are transferred from a stamper placed in a molding die.
For example, the information recording pits 13,
Further, a so-called groove is formed.

The thickness of the substrate 10 is, for example, 0.3 mm or more, which allows injection molding, and may be selected to be less than 1.2 mm, which is equivalent to the thickness of a substrate in a CD or the like.

The thickness t of the light transmitting layer 12 is 3 μm to 182
μm, and the thickness irregularity Δt is ± 5.26λ / (N.
A. ) Within ⁴

A laser beam for reproducing and / or recording is made incident from the light transmitting layer 12 side.

This laser beam has a wavelength range of blue or less, that is, a wavelength λ of 380 nm ≦ λ ≦ 450.
nm laser light; A. (Numerical Aperture) Irradiation through a lens system of 0.76 or more, for example, reading of information,
That is, reproduction is performed.

The track pitch T of the information recording surface
P is set to 0.27 μm to 0.404 μm. The shortest pit length P _min of the information recording pit is 0.13 μm to 0.2
19 μm. The recording linear density LD is 0.146 μm /
It is a pit row not more than bit. Information recording pit depth D
Is set to 31 nm to 75 nm.

The thickness t of the light transmitting layer is preferably 5
0 μm to 120 μm.

In an optical recording medium according to another embodiment of the present invention, as shown in a schematic sectional view of one example in FIG. 2, each of the information recording surfaces has at least one first information recording surface 11A, The second information recording surface 11B and the second information recording surface 11B are each laminated via an intermediate layer 16 made of a light transmitting layer. In the case of this configuration, the sum of the thicknesses of the light transmitting layer and the intermediate layer interposed between the respective information recording surfaces and the incident surface of the laser beam is 3 μm to 182 μm. That is, for example, in the configuration of FIG. 2, the thickness of the transmission layer 12 is set to 3 μm to 182 μm with respect to the first information recording surface 11A, and at the same time, the light transmission layer 12
And the thickness of the intermediate layer 16 is 3 μm to 182 μm. Also in this case, the thickness unevenness between the incident surface and the information recording surface is set within ± 5.26λ / (NA) ⁴ .

As for the first information recording surface 11A, the track pitch TP of the information recording surface is 0.27 μm to 0.40, as described in the configuration of FIG.
4 μm, and the minimum pit length P _min of the information recording pit is
0.13 μm to 0.219 μm, and the recording linear density LD
Is a pit row of 0.146 μm / bit or less, and the depth D of the information recording pit is 31 nm to 75 nm.

On the other hand, the track pitch TP of the second information recording surface 11B is 0.45 μm to 0.5
7 μm, and the shortest pit length P _min of the information recording pit is
0.21 μm to 0.31 μm, and the recording linear density LD is:
The pit row is 0.21 μm / bit or less. The depth D of the information recording pit is set to 57 nm to 113 nm.

Then, with respect to the first information recording surface 11A, a laser beam having a wavelength λ of 380 nm ≦ λ ≦ 450 nm A. (Numerical aperture) Irradiation is performed through an optical system having a numerical aperture of 0.76 or more.
Emits a laser beam having a wavelength of 635 nm ≦ λ ≦ 680 nm.
A. Irradiation is performed through an optical system having a (numerical aperture) of 0.76 or more to perform at least one of recording and reproduction.

The configuration of the optical recording medium according to the present invention will be further described. First, the second information recording surface 11B on which reproduction and / or recording is performed by laser light in the red wavelength range will be described. DVD (Digital Versatile Disc or Digital Vi
deoDisc), in the area of the information signal portion, that is, within a radius of 24 mm to 58 mm from the center,
The wavelength is 0.65 μm, the numerical aperture (NA) is 0.6, and the storage capacity is 4.7 GB. Therefore,
In order to realize a storage capacity of 8 GB based on this, the capacity (in this case, density) must be N.D. A. 8 / 4.7 = {(NA./0.6)×(0.65/λ)} ² ... (8 / 4.7 = {NA / 0.6) × (0.65 / λ)} 1) Make sure that

The laser having a wavelength in the red wavelength range has a wavelength λ of 635 nm ≦ λ ≦ 680 nm, specifically, 0.8 nm.
There are laser beams of 635 μm, 0.650 μm, and 0.680 μm. However, considering higher recording density, the laser beam having a shorter wavelength, λ = 0.635 μm, is used. Where λ = 0.635
8 / 4.7 = ｛(NA / 0.6) ×
(0.65 / 0.635)｝ ² ... (1 ₁ ). A. = 0.76.

Λ = 0.635 μm, N.P.
A. = 0.76, each track pitch P, shortest pit length P _min , and linear density LD for achieving a recording capacity of 8 GB are 4.74 μm and shortest pit length in a 4.7 GB DVD. Since the track density is 0.40 μm and the line density is 0.267 μm / bit, TP = 0.74 / ８ (8/4) in consideration of both the line direction and the width direction of the track and on the assumption that the modulation method is EFM. .7) = 0.57 μm P _min = 0.40 / √ (8 / 4.7) = 0.31 μm LD = 0.267 / √ (8 / 4.7) = 0.21 μm /
bit.

As will be described later, the lens system has a two-group lens structure, so that A. = 0.95
Since until it practical extent, from (1 ₁₎ of the relationship, TP = 0.74 / (0.95 / 0.6 × 0.65 / 0.635) = 0.45μm P min = 0.40 / (0.95 / 0.6 × 0.65 / 0.635) = 0.24 μm LD = 0.267 / (0.95 / 0.6 × 0.65 / 0.635) = 0.16 μm / bit In the present invention, the track pitch TP is
0.45μm ~ 0.57μm, the shortest pit length P
_min to 0.24 μm to 0.31 μm, and the recording linear density L
D is a pit row of 0.21 μm / bit or less.

Here, the modulation method for the optical disk is EF
There are an M (2-7) system and a 1-7 system, and the ratio of the shortest pit length: channel bit length: signal bit length in each system is 3: 1: 2, 1-7 system in the EFM system. At 4:
2: 3. From this relationship, when the 1-7 system is used for the same density, the pit length is reduced to 8/9. When this is multiplied, the shortest pit becomes 0.12 μm.

On the other hand, when the pit depth D is the deepest,
The modulation degree is maximized at ４ of the wavelength λ.
Since the push-pull signal in the well-known push-pull method is maximized, it is required to be within these ranges. Therefore, the above-described red laser has a long wavelength of 680 nm and a short wavelength of 635 nm. 680/4 / 1.5 = 113 nm 635/8 / 1.5 = 57 nm. That is, in the present invention, the pit depth D is
57 nm to 113 nm.

On the other hand, the information recording surface 11A has a shorter wavelength laser beam, that is, blue or a shorter wavelength of 450 nm or less, for example, SHG than the red laser beam.
(Second harmonic generation) Laser light of 430 nm using a device, 400 nm of a semiconductor laser, and further 380 nm is used. In this case,

TP = 0.74 × (0.45 / 0.65 × 0.6 / 0.76) = 0.404 μm P _min = 0.40 × (0.45 / 0.65 × 0.6 / 0.76) = 0.219 μm LD = 0.267 × (0.45 / 0.65 × 0.6 / 0.76) = 0.146 μm / bit.

As will be described later, the lens system has a two-group lens structure, so that A. = 0.95
TP = 0.74 × (0.38 / 0.65 × 0.6 / 0.95) = 0.27 μm P _min = 0.40 × (0.38 / 0.65 × 0.6 / 0.95) = 0.14 μm LD = 0.267 × (0.38 / 0.65 × 0.6 / 0.95) = 0.09 μm / bit As for the information recording surface 11A, A pit train having a track pitch TP of 0.27 μm to 0.0.404 μm, a shortest pit length P _min of 0.14 μm to 0.219 μm, and a recording linear density LD of 0.146 μm / bit or less. It is.

Regarding the shortest pit length, 1-
Since it becomes 8/9 in 7 systems, it becomes 0.13 μm.

On the other hand, the tolerance (skew margin) SM of the inclination of the optical recording medium with respect to the optical axis of the irradiation laser light has a relationship of SM∝λ / (NA) ³ / t. A. If you increase
It is necessary to reduce the thickness t of the light transmitting layer 12 through which the laser light traveling toward the information recording surface 11 is transmitted.
According to Japanese Patent Laid-Open Publication No. 3-225650, it is known that the skew margin SM only needs to satisfy the relationship of | SM | ≦ 84.115 ° (λ / (NA) ³ / t). I have.

This can be applied to the optical recording medium of the present invention, and it is appropriate that this SM is 0.4 ° as a specific limit value. Now, SM =
0.4 ° to shorten the wavelength of the laser, A. How much the thickness of the light transmitting layer should be set by the application.
As a laser beam, λ = 0.
Considering compatibility with 38 μm, N.I. A. If the above condition of 0.76 or more is not changed, the thickness t of the light transmitting layer is t = 182 μm.

On the other hand, the lower limit of the thickness of the light transmitting layer is determined by whether or not the protective function of the light transmitting layer, which also has a role of protecting the recording film and the reflective film, is secured. That is, the reliability of the optical recording medium and the high N.I. A. It is necessary that the thickness be 3 μm or more in consideration of the influence of the collision of the lens with the light transmitting layer and the light transmitting layer surface due to the approach of the lens. Therefore, in the present invention, the thickness t of the light transmitting layer is set to 3 μm to 182 μm.

Further, high accuracy is required for the thickness unevenness of the light transmitting layer. When the thickness of the light transmitting layer deviates from the design center of the reproduction objective lens, the amount of aberration given to the laser beam spot by the thickness unevenness is determined by N.I. A. And is proportional to the wavelength λ. Therefore, high N.I. A. In order to increase the recording density by reducing the wavelength or shortening the wavelength, the thickness unevenness of the light transmitting layer is more severely limited. As a specific system example, in the case of a CD, the N.V. A. = 0.45 has been put to practical use, and the standard for the thickness unevenness of the light transmitting layer (substrate in the case of CD) is ± 100 μm. In the case of DVD, N.V. A. = 0.6, and the same thickness unevenness is defined as ± 30 μm. CD tolerance ±
On the basis of 100 μm, the thickness unevenness Δt is represented by the following equation. Δt = ± (0.45 / NA) ⁴ × (λ / 0.78) × 100 = ± 5.26 × (λ / (NA) ⁴ ) μm

Further, in increasing the capacity of the above-mentioned optical recording medium, N.I. A. The thickness t of the light transmitting layer at 0.85
Is 0.6 × (0.6 / 0.85) ^{3 in} order to obtain an SM equal to the skew margin SM of the DVD.
= 0.21 mm or less. Further, in consideration of compatibility with a blue-violet laser having a wavelength of about 400 nm, 0.21 × 0.4 / 0.65 = 0.129 mm, and the thickness t of the light transmitting layer should be 0.12 mm or less. become.

In order to actually form the light transmitting layer 12, for example, application of a resin or adhesion of a resin sheet can be considered. In addition, there is a problem that the outermost peripheral portion is raised by spin-coating the resin. Therefore, as shown in a schematic cross-sectional view of another embodiment in FIG. 3, it is considered that an effective method is to form a transparent resin sheet 14 by bonding it with a transparent adhesive layer 15. In this case, When the thickness of the resin sheet is less than 50 μm, the birefringence is large and the signal characteristics are affected.
It is preferably at least 0 μm. In addition, the thickness t of the light transmitting layer may be 50 μm or more from the viewpoint of the adhesion of dust on the light transmitting layer, the influence on the recording / reproducing laser light spot due to the generation of scratches, and the instability of the servo due to this. preferable.

From the above, the thickness t of the light transmitting layer is:
It is more preferable that the thickness be 50 μm to 120 μm.

Further, the structure of the optical recording medium according to the present invention will be described. The row of the above-mentioned pits P in the optical recording medium according to the present invention is shown in FIG. As shown in FIG. 4B, a configuration formed on a single or one spiral wire,
In the illustrated example, a plurality of spiral lines may be formed.

FIG. 5 shows a schematic pattern diagram of the information pits P on the information recording surfaces 11A and 11B.
It is also possible to adopt a configuration in which a recordable area 40 indicated by diagonal lines is provided in an area other than the formation part of. This recordable area 40 can be a single or a plurality of spirals as in the pit row described above.

A plurality of double spirals (2
In the case of a configuration such as a book (parallel spiral), a spiral groove is formed, and a recordable area is formed in each of the so-called lands within the groove and between the grooves. A configuration such as forming P can be adopted.

Further, as shown in the schematic pattern diagram of FIG. 6A, a spiral groove Grv shown by hatching.
Is formed, and the land Gnd and the land Lnd between the groove Grv are formed.
6B and 6C, the groove Grv and the land Lnd may be formed continuously, as shown in FIGS. 6B and 6C. Various arrangements can be adopted, such as a configuration in which a row of pits P is formed.

Further, as described above, the first and second information recording surfaces 11A and 11B having different structures, respectively.
Are laminated, for example, via an intermediate layer 16 made of an ultraviolet curable resin.

In this case, the thickness t of the light transmitting layer with respect to the second information recording surface 11 B is, as described above, the intermediate layer 16.
And the light transmission layer 12 on the surface.

In this case, the information recording surface 11A corresponding to the shorter wavelength is disposed on the laser beam incident side of the second information recording surface 11B, that is, on the side closer to the objective lens of the optical recording / reproducing apparatus. Is preferred. This is because the skew margin becomes more severe as the wavelength becomes shorter.

In each of the above-described configurations, a reflection film is formed on the information recording surface 11A having a pit array, ie, a ROM configuration. When the information recording surface has a multilayer structure, the reflection film on the laser incident side is translucent. Further, in the recordable area, a rewritable or one-time writing so-called WO type or the like structure can be employed. For example, a recording mode in which optical characteristics change due to a change between polycrystallization and amorphous by laser irradiation. In the case of the so-called phase change type, a phase change material layer is formed. Also, if necessary, a reflection film can be formed on the formation surface of the recordable area, for example, on the groove and land surfaces.

In each of the above-described examples, for example, the information recording surface 11A may be formed in a multilayer structure, or the first and second information recording surfaces 11A and 11B may be formed in a multilayer structure. However, the present invention is not limited to the illustrated example.

The optical recording / reproducing apparatus according to the present invention uses each optical recording medium M, for example, an optical disk, having the above-mentioned information recording surface 11A or the first and second information recording surfaces 11A and 11B. FIG. 7 shows an optical recording / reproducing apparatus for optically performing reproduction and / or recording with respect to the optical recording / reproducing apparatus. For example, in an optical recording / reproducing apparatus for an optical recording medium having only the information recording surface 11A, 380 nm ≦ λ ≦ 450 nm
A laser light source unit (not shown) capable of obtaining a laser beam having a wavelength λ in the range of
N. A. (Numerical Aperture) For example, an optical recording medium M that is rotationally driven through an optical system having an aperture of 0.76 or more, that is,
From the light transmitting layer 12 side in a direction perpendicular to the direction of the light transmission layer 12 to reproduce and / or record information recorded on the information recording surface.

Further, the above-mentioned 635 nm ≦ λ ≦ 680 n
A recording / reproducing apparatus that reproduces and / or records data on an optical recording medium having a second information recording surface using a laser beam of m is also provided with the above-described 380 nm ≦ λ ≦ 450 nm, as shown in FIG. A laser light source unit (not shown) capable of obtaining a laser beam having a wavelength λ in a range is set as a first light source unit.
A light source unit (not shown) of a laser beam L with m ≦ λ ≦ 680 nm is provided as a second light source unit, and both laser beams are applied to an optical recording medium M by the first and second information recording surfaces 11.
It is configured to switch and irradiate depending on which of the information recording surfaces A and 11B performs reproduction and / or recording.

The optical system of each of the above-mentioned optical recording / reproducing apparatuses can be constituted by the two-group lens systems 31 and 32.
A. Can be obtained. These lens systems 31 and 3
2 can be formed not only by a single lens having lens surfaces 31a and 31b and 32a and 32b each having a required curved surface, but also as a lens group by a plurality of lenses.

The second lens system 3 in this optical system
2 and 33 can be configured so that the distance between them can be changed and adjusted. As described above, the variable configuration can cancel the wavefront aberration caused by the change in the thickness of the light transmitting layer, thereby simplifying the design and manufacturing of the optical recording medium and the optical recording / reproducing apparatus, and improving the recording / reproducing. It is possible to stabilize reproduction and improve characteristics.

As described above, according to the present invention, an optical recording medium capable of performing a large-capacity recording of, for example, 8 GB and a reproduction and / or recording of the optical recording medium can be performed while keeping the skew margin at the level of DVD. It is possible to configure an optical recording apparatus for performing the above.

In the above-mentioned optical recording medium, one or more information recording surfaces are formed on one surface of the substrate 10. In this manner, two optical recording media each having an information recording surface are formed. By laminating the substrate 10 on the side opposite to the side on which each information recording surface is formed, a double-sided optical recording medium can be formed. The optical recording medium and the optical recording / reproducing apparatus according to the present invention can be variously modified and modified so that the recording surface is irradiated with laser light.

In the present specification, it is needless to say that the term “transparent or light-transmitting” refers to a material having transparency to a laser beam used.

[0054]

As described above, according to the present invention, a large-capacity recording of, for example, 8 GB can be achieved in an optical recording medium for reproducing and / or recording while keeping the skew margin to the extent of a DVD. And an optical recording apparatus for reproducing and / or recording the same.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of an optical recording medium according to the present invention.

FIG. 2 is a schematic sectional view of another example of the optical recording medium according to the present invention.

FIG. 3 is a schematic sectional view of another example of the optical recording medium according to the present invention.

FIGS. 4A and 4B are pattern diagrams of a pit row in an example of an optical recording medium according to the present invention.

FIG. 5 is a pattern diagram of a pit row in an example of an optical recording medium according to the present invention.

6A to 6C are information pattern diagrams of examples of an optical recording medium according to the present invention.

FIG. 7 is a configuration diagram of a main part of an example of an optical recording / reproducing apparatus according to the present invention.

[Explanation of symbols]

M: optical recording medium, 10: base, 11A: first information recording surface, 11B: second information recording surface, 12
... light transmission layer, 13 ... information recording pit, 14 ...
・ Sheet, 15 ・ ・ ・ Intermediate layer, 31 ・ ・ ・ First lens, 32 ・ ・ ・ Second lens, 31a, 31b, 32
a, 32b: lens surface, 40: recordable area,
P ・ ・ ・ pit

Claims (22)

[Claims] 1. A light transmitting layer is formed on an information recording surface on which information recording pits are formed, and a wavelength λ from the light transmitting layer side.
Emits a laser beam having a wavelength of 380 nm ≦ λ ≦ 450 nm.
A. The information is read out by irradiating through a lens system having a (numerical aperture) of 0.76 or more. In the signal recording area, the thickness of the light transmitting layer is 3 μm to 182 μm, and the thickness unevenness of the light transmitting layer is provided. Is ± 5.26λ / (N.
A. ⁴ ) The track pitch of the information recording surface is 0.27 μm or more.
0.404 μm, and the shortest pit length of the information recording pit is 0.13 μm to
An optical recording medium comprising: 0.219 μm; a pit row having a recording linear density of 0.146 μm / bit or less; and a depth of the information recording pit being 31 nm to 75 nm. 2. The optical recording medium according to claim 1, wherein said pit row is formed of one or more spirals. 3. The thickness of the light transmitting layer is 50 μm to 12 μm.
2. The optical recording medium according to claim 1, wherein the optical recording medium has a thickness of 0 μm. 4. The optical recording medium according to claim 1, wherein the information recording surface is formed by laminating two or more layers. 5. The optical recording medium according to claim 1, wherein a recordable area is provided in an area of the information recording surface other than a part where the information pit is formed. 6. The optical recording medium according to claim 5, wherein said recordable area comprises one or more spirals. 7. The optical recording medium according to claim 1, wherein an information recording surface having the information recording pits and an information recording surface having a recordable area are provided in a stacked manner. 8. The optical recording apparatus according to claim 7, wherein the information recording surface having the pit row is arranged closer to a laser beam incident side than the information recording surface having the recordable area. Medium. 9. A light transmitting layer is formed on an information recording surface on which information recording pits are formed, and the thickness of the light transmitting layer is 3 μm.
182 μm, and the thickness unevenness of the light transmitting layer is ±
5.26λ / (NA) ^{4 or} less, and the track pitch of the information recording surface is 0.27 μm to 0.404 μm.
And the shortest pit length of the information recording pit is 0.1
3 μm to 0.219 μm, and the recording linear density is 0.1 μm.
A laser beam with a wavelength λ of 380 nm ≦ λ ≦ 450 nm is used for an optical recording medium having a pit row of 46 μm / bit or less and a depth of the information recording pit of 31 nm to 75 nm. A. (Numerical aperture) An optical recording / reproducing apparatus characterized in that it is made incident on the optical recording medium from the side of the light transmitting layer through an optical system having a numerical aperture of 0.76 or more to reproduce recorded information on the information recording surface. . 10. A light transmitting layer is formed on an information recording surface having information recording pits and a recordable area, the light transmitting layer has a thickness of 3 μm to 182 μm, and the light transmitting layer has an uneven thickness. Is within ± 5.26λ / (NA) ⁴ ,
The track pitch of the information recording surface is 0.27 μm
0.404 μm, the shortest pit length of the information recording pit is 0.13 μm to 0.219 μm, the recording linear density is 0.146 μm / bit or less, and the depth of the information recording pit is Is 31 nm to 75 nm
Using a laser light having a wavelength λ of 380 nm ≦ λ ≦ 450 nm. A. (Numerical Aperture) The optical recording medium is made incident on the optical recording medium from the side of the light transmitting layer through an optical system having a numerical aperture of 0.76 or more, and at least one of reproduction and recording of information recorded on the information recording surface is performed. Optical recording and reproducing apparatus. 11. A light transmitting layer is formed on the information recording surface, and a laser beam is irradiated from the light transmitting layer side, wherein the information recording surface has at least one or more first information recording surfaces, A second information recording surface laminated with an intermediate layer formed of a light transmitting layer, and a sum of thicknesses of the light transmitting layer and the intermediate layer between the information recording surfaces and the laser light incident surface. Is 3 μm to 18
2 μm, and the thickness unevenness between the incident surface and all the information recording surfaces is ± 5.2.
6λ / (NA) ⁴ and the track pitch of the first information recording surface is 0.27 μm.
m to 0.404 μm, and the track pitch of the second information recording surface is 0.45 μm.
m to 0.57 μm, and the wavelength λ is 380 nm ≦
Laser light of λ ≦ 450 nm A. (Numerical aperture)
Irradiation through an optical system of 0.76 or more, the wavelength λ of the second information recording surface is 635 nm ≦
Laser light of λ ≦ 680 nm A. (Numerical aperture)
An optical recording / reproducing medium characterized in that at least one of recording and reproduction is performed by irradiation through an optical system of 0.76 or more. 12. The first information recording surface has information recording pits, and the shortest pit length of the information recording pits is 0.
13 μm to 0.219 μm; a pit row having a linear recording density of 0.146 μm / bit or less; a depth of the information recording pits of 31 nm to 75 nm; The information recording pit has a shortest pit length of 0.21 μm to 0.3 μm.
12. The optical recording medium according to claim 11, wherein the pit row has a linear recording density of 0.21 [mu] m / bit or less, and the information recording pit has a depth of 57 nm to 113 nm. 13. The optical recording medium according to claim 11, wherein the first information recording surface is disposed on the laser light incident side of the second information recording surface. 14. The optical recording medium according to claim 12, wherein the first information recording surface is arranged on the laser light incident side of the second information recording surface. 15. A light transmitting layer is formed on the information recording surface, and a laser beam is irradiated from the light transmitting layer side, wherein each of the information recording surfaces has at least one or more first information recording surfaces; A second information recording surface laminated with an intermediate layer formed of a light transmitting layer, and a sum of thicknesses of the light transmitting layer and the intermediate layer between the information recording surfaces and the laser light incident surface. Is 3 μm to 18
2 μm, and the thickness unevenness between the incident surface and all the information recording layers is ± 5.26λ.
/ (NA) ^{4 or} less, and the track pitch of the first information recording surface is 0.27 μm.
m to 0.404 μm, and the track pitch of the second information recording surface is 0.45 μm.
a first laser beam having a wavelength λ of 380 nm ≦ λ ≦ 450 nm and a second laser beam having a wavelength λ of 635 nm ≦ λ ≦ 680 nm using an optical recording medium having a length of m to 0.57 μm.
And N. laser light respectively. A. (Numerical aperture) 0.76
An optical recording / reproducing apparatus characterized in that at least one of recording and reproduction is performed by irradiating the first information recording surface and the second information recording surface through the above optical system. 16. The first information recording surface has information recording pits, and the shortest pit length of the information recording pits is 0.
13 μm to 0.219 μm; a pit row having a linear recording density of 0.146 μm / bit or less; a depth of the information recording pits of 31 nm to 75 nm; The information recording pit has a shortest pit length of 0.21 μm to 0.3 μm.
16. The recording medium according to claim 15, wherein a pit train having a linear recording density of 0.21 [mu] m / bit or less and a depth of the information recording pit of 57 nm to 113 nm is used. Optical recording and reproducing device. 17. The optical recording / reproducing apparatus according to claim 9, wherein said optical system is a two-group lens system. 18. The optical recording / reproducing apparatus according to claim 10, wherein said optical system is a two-group lens system. 19. The optical recording / reproducing apparatus according to claim 15, wherein said optical system is a two-group lens system. 20. The optical recording / reproducing apparatus according to claim 17, wherein a lens interval of the second lens group of the optical system is variable. 21. The optical recording / reproducing apparatus according to claim 18, wherein a lens interval of the second lens group of the optical system is variable. 22. The optical recording / reproducing apparatus according to claim 19, wherein a lens interval of the second lens group of the optical system is variable.