JP2003157585A - Draw type optical recording medium and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DRAW type optical recording medium which does not roughen the surface of an incident surface for a light beam and does not adversely affect recording and reproducing and an optical disk device which subjects this medium to recording or reproducing. SOLUTION: This DRAW type optical recording medium consists of a thin substrate, a thin supporting substrate and a groove forming layer which is formed on this thin supporting substrate and is formed with grooves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a write-once type optical recording medium and an optical disk device for irradiating a light beam to record or reproduce information.

[0002]

2. Description of the Related Art Currently, optical discs are roughly classified into a read-only type and a recordable type. Among these, rewritable types such as DVD-RAM that can record and erase information many times and CD-R,
It is roughly classified into a write-once type that allows additional recording of information such as DVD-R.

Subsequent to the above, a next-generation optical disc capable of recording a larger amount of information is being studied. And
As the NA of the next-generation optical disc increases, it is considered to use a thin substrate as a light transmitting layer. Therefore, various studies have been made on a method of manufacturing the thin substrate, an optical recording medium using the thin substrate, and the like.

Among them, the above-mentioned write-once type will be described. In the write-once type optical recording medium using a thin substrate, the method of changing the groove shape which is the mainstream at present is as follows.
Recording becomes difficult with a combination of a support substrate having a groove and a thin substrate. This is, for example,
As shown in Japanese Patent Application Laid-Open No. 11-191240, when a write-once type optical recording medium compatible with a next-generation optical disc is produced, a reflective layer, a reflective layer, The recording layers are laminated in this order, and a thin substrate is attached to the recording layers to fabricate. Then, a light beam is emitted from the thin substrate side to record or reproduce information on or from the recording layer. In this case, since the reflective layer is sandwiched between the recording layer that absorbs light and the substrate having the groove shape, there is a problem that recording accompanied by the deformation of the groove shape is difficult.

Incidentally, Japanese Patent Laid-Open No. 10-302310 discloses that a guide groove is formed in a thin substrate.
4. As shown in FIG. 12, the grooved light transmitting layer 12 or the thin plate substrate 43 made of polycarbonate 40 is used to form a groove in the polycarbonate 40 using the stamper 41 and the roller 42. Due to the influence of heat, the surface opposite to the surface on which the groove is formed and on which the light beam is incident is roughened, and the incident light beam is diffusely reflected. Therefore, for the recording of information,
There is a problem that a higher-power light source is required and noise is increased when reproducing information, and as a result, high density recording cannot be performed.

[0006]

As described above, in the conventional write-once type optical recording medium, since the groove is formed on the thin substrate, the surface on which the groove is formed is affected by heat in the groove forming process. However, there is a problem in that the surface of the incident surface of the light beam is roughened on the opposite surface, which causes irregular reflection, which adversely affects recording and reproduction.

The present invention solves the above-mentioned problems, and the surface of the incident surface of the light beam is not roughened, and the write-once type optical recording medium which does not adversely affect the recording and reproduction and the recording to this medium. Alternatively, it is an object to provide an optical disk device for reproducing.

[0008]

In order to achieve the above object, a write-once type optical recording medium of the present invention is a write-once type optical recording medium for recording information by an irradiated light beam,
The write-once type optical recording medium is formed on the recording layer, a light transmitting layer disposed on a surface on which the light beam is incident on the write-once type optical recording medium, a recording layer formed on the light transmitting layer. A reflective layer and a supporting substrate provided on the reflective layer,
The light transmitting layer is characterized by comprising a thin supporting substrate and a groove forming layer formed on the thin supporting substrate and having a groove formed therein.

The light transmitting layer located on the light beam incident surface is composed of at least the thin supporting substrate and the groove forming layer, so that the light transmitting layer is affected by heat when the groove is formed on the groove forming layer. Since the light is not transmitted, the surface property of the incident surface is excellent, so that irregular reflection does not occur and higher density recording is possible.

Further, the write-once type optical recording medium is characterized in that the information formed is recorded by deforming the groove formed in the groove forming layer by the irradiated light beam.

In the write-once type optical recording medium in which information is recorded by deforming the shape of the groove, the groove is formed in the light transmitting layer and the light transmitting layer and the recording layer are in direct contact with each other. It is possible to realize a write-once type optical recording medium accompanied by deformation of the groove shape.

Further, the write-once type optical recording medium is characterized by comprising an adhesive layer for adhering the reflection layer and the supporting substrate.

The thickness of the light transmitting layer is 10 to 198 μm.
Is characterized in that.

In order to achieve a high recording density, a lens having a high aperture is required, which reduces the working distance, so that the distance between the optical disk and the lens should be close to 198 μm or less. Need to Further, if it is less than 10 μm, the mechanical properties are deteriorated, so that 10 μm or more is required. Therefore, the thickness allows the distance between the optical disk and the lens to be reduced without deteriorating the mechanical characteristics.

Further, the light transmission layer is characterized by being composed of two different light transmission resin layers.

The groove shape transferability, heat resistance,
It is possible to obtain an optical recording medium having excellent moldability, small birefringence, and excellent optical characteristics.

The thickness of the supporting substrate is 0.5 to 1.2 mm.
Is characterized in that.

Since the light beam is incident from the light transmitting layer side for recording, the optical characteristics of the supporting substrate are not limited, and the thickness of the supporting substrate improves mechanical characteristics and durability. You can

The depth of the groove is 20 to 200 nm.
Is characterized in that.

Further, when the depth is set to the above range, molding is easy and stable tracking can be performed. This is because if it is thicker than 200 nm, molding becomes difficult, and if it is less than 20 nm, tracking (servo) becomes unstable.

In addition, the recording layer is made of an organic dye film.

As a result, a sufficient refractive index (n) can be obtained as compared with other organic materials.

The reflective layer is an alloy containing at least one selected from the group consisting of gold, silver, copper, platinum and aluminum.

By using the above alloy, the reflective layer has excellent reflection characteristics and surface properties after film formation.

The recording layer is made of a material having a refractive index n of 2 or more and an extinction coefficient k of 0.5 to 2.5, and further includes nitrides, oxides, carbides, borides, sulfides, fluorides, etc. thereof. And a mixture thereof.

By setting the recording layer to the above,
Since all steps of the recording layer and the reflective layer can be performed by the sputtering device, the manufacturing process can be shortened and the cost can be reduced.

Further, the recording layer is characterized by being composed of Si, Ge, simple substances such as nitrides, oxides, carbides, borides, sulfides and fluorides thereof, and mixtures thereof.

Further, in the optical disc device of the present invention, the write-once type optical recording medium is an optical disc device for recording information by irradiating a light beam, and the optical disc is used as the write-once type optical recording medium. A light-transmitting layer disposed on a surface on which a beam is incident on the write-once type optical recording medium, a recording layer formed on the light-transmitting layer, a reflecting layer formed on the recording layer, and provided on the reflecting layer. And a groove forming layer formed on the thin supporting substrate and having a groove formed therein, the light transmitting layer being formed on the thin supporting substrate. A light beam irradiating means for irradiating a light beam, a condensing means for condensing the light beam by the light beam irradiating means on a recording layer of the write-once type optical recording medium, and a light beam condensed by the condensing means Is the above Characterized by comprising a position control means for controlling so as to be located in the layer.

An optical disk device for reproducing information by irradiating a write-once type optical recording medium with a light beam, wherein the write-once type optical recording medium is the write-once type optical recording medium. A light-transmitting layer disposed on a surface that is incident on the medium, a recording layer formed on the light-transmitting layer, a reflecting layer formed on the recording layer, and a supporting substrate provided on the reflecting layer, The light transmission layer includes a thin support substrate and a groove forming layer formed on the thin support substrate and having a groove formed therein. The light beam for irradiating the write-once type optical recording medium with the light beam. Irradiation means,
Condensing means for condensing the light beam by the light beam irradiating means on the recording layer of the write-once type optical recording medium, and controlling so that the light beam condensed by the condensing means is positioned on the recording layer. And a position control means.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the write-once type optical recording medium of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a write-once type optical recording medium according to an embodiment. The optical disc 100 has a depth of 20 to 200.
10-198 μm thick thin substrate 1 with nm groove 110
A recording layer 11 of at least an organic dye and a reflective layer 12 are laminated on top of the layer 1, and the thickness is irrelevant to the optical characteristics.
The support substrate 13 having a thickness of 0.5 to 1.2 mm is bonded by the adhesive layer 135. The thin substrate 11 is composed of a photocurable resin 21 and a thin support substrate 25. That is, the thin substrate 11 is composed of two different light-transmissive resin layers, that is, the photocurable resin 21 and the thin support substrate 25. Further, among the unevenness provided on the thin substrate 11, the groove 110 corresponds to a region away from the incident surface of the light beam on the optical disc 100. Then, a light beam having a power for recording information is transmitted from the direction A to the optical disc 1
When a predetermined area of 00 is irradiated, the heat energy of the light beam through the thin substrate 11 is absorbed in the recording layer 12, and the shape of the groove 110 is changed by the influence of this heat, whereby information is recorded.

Thin Substrate 11 Before Groove 110 is Formed
Is produced by extrusion molding or casting. At that time, as the resin material used, a light transmissive resin material such as a polycarbonate resin, a methacrylic resin, an acrylic resin, a polyolefin resin, or an epoxy resin is used.

For the thin substrate 11, the 2P method (Photo polym
erization method) or thermal transfer to form the groove 110. In the 2P method, in order to form the groove 110 on the thin substrate 11, a photocurable resin is mainly used as a new light transmissive resin. This method will be described later.

On the other hand, in the method utilizing thermal transfer,
It is difficult to thermally transfer the groove 110 to the thin substrate 11 made of only the resin material in the thin substrate 11 made of only the resin material because the thin substrate 11 is deteriorated at the time of thermal transfer. Therefore, as shown in FIG. 1, the thin substrate 11 is composed of the thin supporting substrate 25 and the photocurable resin 21. This is capable of thermal transfer at a lower temperature than the thin supporting substrate 25, that is, the photocurable resin 21 as a resin layer made of a resin material having a lower viscosity average molecular weight (Mv) than the resin material of the thin supporting substrate 25, By laminating on the thin support substrate 25 and thermally transferring the groove 110 to the surface of the photocurable resin 21 having a low viscosity average molecular weight (Mv), precise thermal transfer of the groove 110 becomes possible.

Further, in the embodiment of the present invention, in the write-once type optical recording medium in which the shape of the groove 110 is deformed at the time of recording, a reflective film is formed on the supporting substrate on which the groove is formed,
In an optical recording medium in which a recording film is laminated, the reflection film hinders substrate deformation and it is difficult to record. Therefore, a thin substrate 11 in which a groove 110 is formed is produced, and a recording layer 12 is formed thereon. By stacking the reflective layer 13, a write-once type optical recording medium that is deformed in the shape of the groove 110 at the time of recording is made possible.

Next, a method of forming the groove 110 of the thin substrate 11 by the 2P method will be described. 2 shows the groove 11
FIG. 6 is a diagram illustrating a method of manufacturing the thin substrate 11 on which 0 is formed by the 2P method.

First, as shown in FIG. 2A, the photocurable resin 21 as a light transmissive resin layer is applied to the thin support substrate 25 on the thin support substrate 25 prepared by extrusion molding or casting. While being relatively rotated, the thin support substrate 25 is applied in a ring shape along its circumferential direction. As a result, a thin substrate 11 having no groove is produced. In addition, photocurable resin
As the material 21, for example, an ultraviolet curable resin is used. afterwards,
As shown in FIG. 2B, a photocurable resin 21 is applied to the thin substrate 11 prepared in FIG. 2A on a stamper 22 having a groove shape to form a groove 110. The side is matched with the side of the stamper 22 on which the groove shape is formed and abutted. In this state, a constant load is applied from, for example, a thin support substrate 25 arranged on the stamper 22 by using a cylindrical pressing roller or the like (not shown). By this operation, the photocurable resin 21 interposed between the thin support substrate 25 and the stamper 22 is pressed and spreads along the plate surfaces of the thin support substrate 25 and the stamper 22. After that, as shown in FIG. 2C, an ultraviolet lamp (UV
The photocurable resin 21 is cured by irradiating ultraviolet rays with a lamp 200. Then, it is conveyed by a roller or the like (not shown), and the stamper 22, the photocurable resin 21 having the groove formed therein, and the thin support substrate 25 are separated. As a result, FIG.
As shown in (d), the thin substrate 11 having the groove 110 formed on one surface can be manufactured.

Although the method of forming the thin substrate 11 by the 2P method has been described with reference to FIG. 2, it may be formed by another method.

FIG. 3 is a diagram showing a forming method in which the groove is transferred to the thin substrate 11 by thermal transfer.

As shown in FIG. 3A, a groove forming layer 31 made of a resin material having a glass transition temperature lower than that of the thin supporting substrate 35 is formed on the thin supporting substrate 35 formed by extrusion molding or casting. Prepare and bond them using rollers 31 and 32. Next, the stamper 22 heated to a temperature higher than the glass transition point is brought into contact with the groove forming layer 31 and the thin support substrate 35, and pressure is applied to these by a roller 33 to press them. Then, after the roller 33 is separated from the thin support substrate 35, it is processed into a predetermined size, for example, a disk shape, so that the groove 110 is transferred to the groove forming layer 31 as shown in FIG. 3B. The substrate 311 can be manufactured. As a material of the groove forming layer 31, for example, acrylic (PMMA) or amorphous polyolefin (APO) is used as a resin material having a glass transition temperature lower than that of the thin supporting substrate 35.

The upper limit of the thickness of the thin substrates 11 and 311 is about 310 μm, which can be produced by extrusion molding or casting with high thickness accuracy. The thickness needs to be 310 μm or less. On the other hand, the lower limit of the thickness is that the thin substrates 11 and 311 also have a role of protecting the recording layer 12 or the reflective layer 13,
It suffices if it can fulfill the role, and it is used for the reliability of the optical disc 100 and for recording or reproduction of the optical disc 100.
Considering the influence of the collision of the group lens on the surfaces of the thin substrates 11 and 311, it is necessary that the thickness be 10 μm or more.

The thin substrates 11 and 311 having the groove 110 formed by the method shown in FIG.
To complete the process as 0, a recording layer 12 made of an organic dye and a reflective layer 13 are formed on the thin substrates 11 and 311.

The recording layer 12 contains an organic dye material as a recording material. Specific examples of the organic dye material include cyanine-based, phthalocyanine-based, azo metal complex-based, and organic dye-based materials such as organic dyes obtained by substituting these constituent elements with other elements and substituents. You can When forming the recording layer 12, first, an organic dye material which is a recording material is dissolved in a solvent such as alcohol to form a coating material. Then, the coating material containing the organic material is made to have a predetermined thickness by a method such as spin coating, and then the coating film formed by the spin coating method is dried to form the recording layer 12 having a thickness of about 120 nm. It The recording layer 12 may be made of any material other than the organic dye-based material as long as it has sufficient light absorption at the wavelength used and has a refractive index n of 2 or more and an extinction coefficient k of 0.5 to 2.5. But it is possible. Examples include materials made of Si, Ge and the like, or their simple substances such as nitrides, oxides, carbides, borides, sulfides and fluorides, and mixtures thereof. For example, in the case of depositing SiN, it can be deposited by reactive sputtering using a mixed gas of Ar + N2 as a sputtering gas with a sputtering apparatus provided with a Si target or a SiN target.

Next, the reflection layer 13 is provided to improve the reflectance of the irradiated light beam on the thin substrates 11 and 311 during recording or reproduction, and the recording layer 12 and the supporting substrate. Formed between 14. Specifically, as the material of the reflective layer 13, a metal material such as Al, Au, Ag, Cu, or Pt is used. Particularly, from the viewpoint of reflection characteristics, at least A
It is preferable to use a material containing l. Also, the optical disc 10
In a write-once type optical recording medium such as 0, there is a tendency to use a laser beam of a short wavelength for the purpose of high density recording, for example,
Laser light having a wavelength of about 400 nm has come to be used. Therefore, as the reflective layer 13, it is preferable to use a material that exhibits an excellent reflectance with respect to a laser beam having a short wavelength, for example, a laser beam having a wavelength of about 400 nm. As a material that exhibits excellent reflectance with respect to a laser beam having a short wavelength and has excellent surface properties after a film forming process, Ag, Ag alloy, Al alloy, or the like is preferable, and Ag is particularly preferable. Is preferred. The reflective layer 13 is formed of any of the above materials by ion beam sputtering, magnetron sputtering, vacuum deposition, or the like. Specifically, the sputtering method A
The reflective film 12 is formed by depositing g with a thickness of about 100 nm.

Then, a thin substrate in which a recording layer 12 and a reflective layer 13 are laminated by dropping an ultraviolet curable resin as an adhesive layer 135 on a supporting substrate 14 having a thickness of 1.1 mm, which is separately manufactured by injection molding. The optical disc 100, which is a write-once type optical recording medium, can be manufactured by mounting 11 and pressure bonding and irradiating ultraviolet rays from the side of the supporting substrate 14 to bond them. In addition, thin substrates 11, 3
Since the light beam is incident from the 11 side (direction A in FIG. 1) to perform recording, the support substrate 14 does not need to be light transmissive. As a result, any material can be selected as the material of the support substrate 14, so that it is possible to further improve the functions such as mechanical characteristics and durability. Further, the thickness of the support substrate 14 may be arbitrarily determined within the range of 0.5 to 1.2 mm.

It should be noted that in the above-described embodiment, one side is provided on one side.
Although the optical disc 100 having one recording layer 12 has been described, the double-sided optical disc 400 may have the recording layers 12 on both sides as shown in FIG. In this case, the supporting substrate 14 on each surface uses, for example, polycarbonate as a material,
The adhesive layer 4135 is formed by applying μm and is adhered to this. As a result, it becomes possible to record or reproduce information on the two recording layers 12 by making the light beam incident from the B direction in addition to the A direction.

As a modified example of FIG. 4, the supporting substrate 14,
The adhesive layer 4135 and the supporting substrate 14 may be combined to form one supporting substrate. In this case, the thickness of the support substrate is about 1.0 μm. And this facilitates manufacturing.

As a modification of FIG. 4, as shown in FIG. 5, a dummy plate 50 having no recording layer may be provided in place of the one supporting substrate 14 to the thin substrate 11 shown in FIG. In this case, the dummy plate 50 is made of polycarbonate, for example, and is adhered to the support substrate 14 via the adhesive layer 4135. By adjusting the thickness of the dummy plate 50, the total thickness of the optical disc 100 can be made the same as that of the double-sided optical disc 400 of FIG.

Next, an optical disc device for recording and reproducing information on the write-once type optical recording medium of the present embodiment will be described.

FIG. 6 is a diagram showing a schematic structure of an optical disk device relating to the write-once type optical recording medium of the present embodiment. This optical disc apparatus records target information (data) on the optical disc 100 described above, and
Plays back the data recorded in 0.

As shown in FIG. 6, the optical disk device includes a modulation circuit 602, a laser control circuit 603, a laser 604, a collimating lens 605, a polarization beam splitter (hereinafter, PBS) 606,
Quarter-wave plate 607, objective lens 608, condenser lens 609,
It includes a photodetector 610, a signal processing circuit 611, a demodulation circuit 612, a focus error signal generation circuit 613, a tracking error signal generation circuit 614, a focus control circuit 616, and a tracking control circuit 617.

First, recording of data by this optical disk device will be described. The recording data is modulated by the modulation circuit 602 into a predetermined channel bit sequence. The channel bit sequence corresponding to the recorded data is the laser control circuit 60
Converted to laser drive waveform by 3. Laser control circuit 6
In 03, the laser 604 is pulse-driven to record data corresponding to a desired bit sequence on the optical disc 100. Laser 6
The recording light beam emitted from 04 is collimated by the collimator lens 605, enters the PBS 606, and is transmitted. PBS
The beam transmitted through 606 passes through the quarter-wave plate 607 and is focused on the information recording surface of the optical disc 100 by the objective lens 608. The focused beam is maintained by the focus control by the focus control circuit 616 and the tracking control by the tracking control circuit 617 such that the best minute spot can be obtained on the recording surface.

Next, the reproduction of data by this optical disk device will be described. Based on the data reproduction instruction, the laser 604 emits a reproduction light beam. The reproducing light beam emitted from the laser 604 is collimated by the collimator lens 605.
Then, it becomes parallel light, which is incident on PBS606 and transmitted. The light beam transmitted through the PBS 606 passes through the quarter-wave plate 607 and is focused on the information recording surface of the optical disc 100 by the objective lens 608. The focused beam is maintained by the focus control by the focus control circuit 616 and the tracking control by the tracking control circuit 617 such that the best minute spot can be obtained on the recording surface. At this time, the reproduction light beam irradiated on the optical disc 1 is
Is reflected by the recording layer 12 and the reflective layer 13. The reflected light passes through the objective lens 608 in the opposite direction and becomes parallel light again. The reflected light passes through the quarter-wave plate 607, has a polarization perpendicular to the incident light, and is reflected by the PBS 606. The beam reflected by the PBS 606 is converged by the condenser lens 609 and is incident on the photodetector 610. The photodetector 610 is composed of, for example, a four-divided photodetector. Photo detector 610
The light flux incident on is photoelectrically converted into an electric signal and amplified. The amplified signal is equalized by the signal processing circuit 611, binarized, and sent to the demodulation circuit 612. The demodulation circuit 612 performs a demodulation operation corresponding to a predetermined modulation method, and outputs reproduced data.

Further, based on a part of the electric signal output from the photodetector 610, the focus error signal generation circuit 613
Produces a focus error signal. Similarly, the tracking error signal generation circuit 614 generates a tracking error signal based on a part of the electric signal output from the photodetector 610. The focus control circuit 616 is
The focus of the beam spot is controlled based on the focus error signal. The tracking control circuit 617 controls the tracking of the beam spot based on the tracking error signal.

[0055]

As described above, according to the write-once type optical recording medium of the present invention, the surface of the incident surface of the light beam is not roughened, and there is no adverse effect on recording and reproduction. be able to. Further, this effect is the same in the optical disk device.

[Brief description of drawings]

FIG. 1 is a sectional view of a write-once type optical recording medium according to an embodiment of the present invention.

FIG. 2 is a diagram showing a groove forming method (2P method) on a write-once type optical recording medium according to an embodiment of the present invention.

FIG. 3 is a diagram showing a groove forming method (thermal transfer method) on a write-once type optical recording medium according to an embodiment of the present invention.

FIG. 4 is a diagram showing a double-sided write-once type optical recording medium according to an embodiment of the present invention.

FIG. 5 is a diagram showing a modification of the write-once type optical recording medium according to the embodiment of the invention.

FIG. 6 is a block diagram showing a schematic configuration of an optical disc device for recording and reproducing information on the write-once type optical recording medium according to the embodiment of the present invention.

[Explanation of symbols]

11, 311 ... Thin substrate 12 ... Recording layer 13 ... Reflective layer 14 ... Support substrate 21 ... Photocurable resin 22 ... Stamper 25, 35 ... Thin support substrate 31 ... Groove forming layer 50 ... dummy plate 100 ... Optical disc 110 ... groove 135, 4135 ... Adhesive layer 200 ... UV lamp 400 ... Double-sided optical disk 602 ... Modulation circuit 603 ... Laser control circuit 604 ... Laser 605 ... Collimating lens 606 ... Polarizing beam splitter (PBS) 607 ... Quarter wave plate 608 ... Objective lens 609 ... Condenser lens 610 ... Photodetector 611 ... Signal processing circuit 612 ... Demodulation circuit 613 ... Focus error signal generation circuit 614 ... Tracking error signal generation circuit 616 ... Focus control circuit 617 ... Tracking control circuit

Claims (9)

[Claims] 1. A write-once type optical recording medium for recording information by an irradiated light beam, wherein the write-once type optical recording medium is arranged on a surface on which the light beam is incident on the write-once type optical recording medium. A light-transmitting layer, a recording layer formed on the light-transmitting layer, a reflecting layer formed on the recording layer, and a support substrate provided on the reflecting layer, wherein the light-transmitting layer is a thin support. A write-once type optical recording medium comprising a substrate and a groove forming layer formed on the thin support substrate and having a groove formed therein. 2. The write-once type optical recording medium is characterized in that the information is recorded by deforming the groove formed in the groove forming layer by the irradiated light beam. The write-once type optical recording medium described. 3. The write-once type optical recording medium according to claim 1, wherein the write-once type optical recording medium comprises an adhesive layer for adhering the reflection layer and the supporting substrate. 4. The write-once type optical recording medium according to claim 1, wherein the thickness of the light transmitting layer is 10 to 198 μm. 5. The optical recording medium according to claim 1, wherein the light transmitting layer is composed of two different light transmitting resin layers. 6. The write-once type optical recording medium according to claim 1, wherein the support substrate has a thickness of 0.5 to 1.2 mm. 7. The write-once type optical recording medium according to claim 1, wherein the depth of the groove is 20 to 200 nm. 8. An optical disc apparatus for recording information by irradiating a write-once type optical recording medium with a light beam, wherein the write-once type optical recording medium is the write-once type optical recording medium. A light transmissive layer disposed on a surface incident on the medium, a recording layer formed on the light transmissive layer, a reflective layer formed on the recording layer, and a support substrate provided on the reflective layer, The light transmitting layer includes a thin supporting substrate and a groove forming layer formed on the thin supporting substrate and having a groove formed therein. A light beam for irradiating the write-once type optical recording medium with the light beam Irradiating means, a condensing means for condensing the light beam by the light beam irradiating means on the recording layer of the write-once type optical recording medium, and the light beam condensed by the condensing means is located on the recording layer. To control Optical disk apparatus characterized by comprising a 置制 control means. 9. An optical disc apparatus for reproducing information by irradiating a write-once optical recording medium with a light beam, wherein the write-once optical recording medium is the write-once optical recording medium. A light transmissive layer disposed on a surface incident on the medium, a recording layer formed on the light transmissive layer, a reflective layer formed on the recording layer, and a support substrate provided on the reflective layer, The light transmitting layer includes a thin supporting substrate and a groove forming layer formed on the thin supporting substrate and having a groove formed therein. A light beam for irradiating the write-once type optical recording medium with the light beam Irradiating means, a condensing means for condensing the light beam by the light beam irradiating means on the recording layer of the write-once type optical recording medium, and the light beam condensed by the condensing means is located on the recording layer. To control Optical disk apparatus characterized by comprising a 置制 control means.