HK1074694B - Optical disk, method for producing the same, and recording and reproducing apparatus - Google Patents

Description

Optical disk, method of manufacturing the same, and recording/reproducing apparatus

Technical Field

The present invention relates to an optical disc, a method of manufacturing the same, and a recording/reproducing apparatus, and more particularly, to an optical disc, a method of manufacturing the same, and a recording/reproducing apparatus, which stably reproduce information recorded on optical discs having different reflectances.

Background

The recent DVDs include not only DVD-ROMs and DVD-videos dedicated to information reproduction but also DVD-rs capable of recording information, DVD-RAMs and DVD-RWs capable of rewriting information. Accordingly, the DVD market is rapidly expanding not only as an image recording and reproducing medium that changes in VTR but also as a large capacity medium for computers. In addition, recently, along with the spread of digital broadcasting, there are increasing demands for media that can correspond to high-precision color images, long-time video recording, and large-capacity storage media that can correspond to increasing amounts of digital data.

In the past, in the field of optical discs, various techniques for increasing the density have been proposed. For example, a method of forming minute recording marks by using a blue laser light (λ 405nm) having a short wavelength, a method of recording information in both a non-pit portion (1and) and a groove (groove) of an optical disc, and the like have been proposed to increase the density. In addition, from the viewpoint of formatting, various proposals have been made for optical discs, and not only the data recording section but also the header section structure of address information and the like are devised and stored. For example, in iD-photo, the guide groove is deflected in the radial direction of the track, and information of the header portion is recorded only on one side of the recording track, whereby the formatting efficiency can be improved, and the recording track can be configured to be continuously long.

As a technique for an optical disk capable of rewriting information, a phase-change recording method such as DVD-RAM or DVD-RW is generally used. In the optical disk of the phase-change recording system, a phase-change material is used for the recording layer, and information of "0" and "1" is recorded basically in correspondence with the crystalline state (unrecorded state) and the amorphous state (recorded state) of the phase-change material, respectively. In addition, since the refractive index is different between the crystalline and amorphous regions formed in the recording layer, the refractive index, the film thickness, and the like of each layer constituting the optical disc are designed so that the difference in reflectance between the crystalline and amorphous regions is maximized. In an optical disk of the phase change recording method, a light beam is irradiated to a crystalline portion and an amorphous portion, a difference in the amount of reflected light from each portion of the optical disk is detected, and "0" and "1" recorded in a recording layer are detected.

In order to amorphize a predetermined position of a recording layer of an optical disc of the phase-change recording method (this operation is generally referred to as "recording"), a relatively high-power light beam is irradiated and heated so that the temperature of the irradiated portion of the recording layer is equal to or higher than the melting point of the material of the recording layer. On the other hand, in order to crystallize a predetermined position of the recording layer (this operation is generally referred to as "erasing"), a light beam of relatively low power is irradiated, and the temperature of the irradiated portion of the recording layer is heated to a temperature near the crystallization temperature or lower than the melting point of the material of the recording layer. In this way, in the optical disk of the phase-change recording system, by adjusting the irradiation power of the light beam irradiated on the recording layer, a predetermined portion in the recording layer can be reversibly changed between an amorphous state and a crystalline state.

In addition, in the conventional optical disc of the phase change recording system, it has been attempted to improve various properties of the optical disc by adjusting the magnitude relation of the reflectance of the amorphous state and the crystalline state in addition to increasing the difference in reflectance in the recording layer. For example, in a general DVD-RAM or DVD-RW, the reflectance of a crystalline portion corresponding to an unrecorded state is set to increase, and the reflectance of an amorphous portion corresponding to a recorded state is set to decrease. Accordingly, in such an optical disc, since address information is recorded in an unrecorded area, the address information is obtained at a high S/N, which is advantageous in that the reliability of address information reproduction is improved. In such an optical disc, since both the focus (focus) servo signal and the tracking servo signal are obtained from an unrecorded area, there is an advantage that the focus (focus) servo signal and the tracking servo signal are obtained with sufficient strength, and tracking control can be stably performed.

On the other hand, as a technique for a write once (write once) optical disc capable of recording information at once, a method of forming a recording layer with a material having an organic pigment is generally used as in DVD-R and the like. When information is recorded on a recording layer containing an organic dye, a relatively high-power light beam is irradiated, whereby at least one of a change in optical constant of the organic dye in the recording layer, deformation of the recording layer and a substrate close to the recording layer, a deformation of the reflective layer, a void generated at an interface of the recording layer, and the like is generated, and a recording mark is formed in the recording layer. In the DVD-R, similarly to the DVD-RAM and DVD-RW, there is an advantage that the reliability of address information reproduction is improved by obtaining address information at a high S/N by setting the reflectance in an unrecorded state to be increased and the reflectance in a recorded state to be decreased. Further, since the focus (focus) servo signal and the tracking servo signal are obtained from an unrecorded area, there is an advantage that the focus (focus) servo signal and the tracking servo signal are obtained with sufficient strength, and tracking control can be stably performed.

In this specification, an optical disc in which information is recorded by irradiating a light beam, and the reflectance of an irradiation portion (a portion in a recording state) of the light beam changes from a High value to a Low value as in conventional DVD-RAM, DVD-RW, and DVD-R is called a High to Low disc or an HL disc. In general, an HL disk of the phase change recording system has a structure including, in order from the light beam incident side, at least a protective layer made of a transmissive dielectric, a phase change recording layer, an intermediate layer made of a transmissive dielectric, and a thermal diffusion layer (also having a function of a reflective layer) made of a metal. In general, an HL disk including a recording layer containing an organic dye has a structure including, in order from the light beam incident side, at least a recording layer containing an organic dye and a thermal diffusion layer (also having a function of a reflective layer) made of a metal.

Further, among conventional optical discs of the phase-change recording system, there has been proposed an optical disc set such that a region in a crystalline state corresponding to an unrecorded state in a recording layer of the optical disc has a low reflectance and a region in an amorphous state corresponding to a recorded state has a high reflectance (see, for example, patent document 1). The optical disc disclosed in patent document 1 has a great advantage of being erased when new information is rewritten (written) on old information.

On the other hand, in an optical disc using a recording layer containing an organic dye (hereinafter referred to as an "organic dye type optical disc"), the reflectance of an area in an unrecorded state is set to be low, and the reflectance of an area corresponding to a recorded state is set to be high. Specifically, when the recording mark is formed, the recording mark is formed by avoiding as much as possible the deformation of the recording layer, the substrate and the reflective layer, and the occurrence of voids in the recording layer or in the interface of the recording layer, depending on the change in the optical constant of the organic dye in the recording layer, whereby the reflectance of the region in the unrecorded state can be reduced, and the reflectance of the region corresponding to the recorded state can be increased. Such an optical disc has an advantage of improving recording sensitivity because the reflectance of an unrecorded area is reduced.

In the present specification, an optical disc in which information is recorded by irradiating a light beam, as in the optical disc disclosed in patent document 1, and thereby the reflectance of the irradiation portion (portion in a recording state) of the light beam is changed from a Low value to a High value is referred to as a "Low to High disc" or simply as an "LH disc". The LH disc of the phase-change recording system has a structure of a multilayer film such as a recording layer/dielectric layer, a recording layer/metal reflective layer, a dielectric layer/recording layer/dielectric layer/metal reflective layer, and the reflectivity of a crystalline region corresponding to an unrecorded state is reduced and the reflectivity of an amorphous region corresponding to a recording region is improved by utilizing an interference effect between films constituting the multilayer film.

Further, at present, a material having a chemical composition consisting of ZnS-SiO has been proposed₂/SiO₂/ZnS-SiO₂/Ge₂Sb₂Te₅/ZnS-SiO₂Alloy form of/A1The resultant LH disk of the multilayer film structure of the phase-change recording system (see, for example, non-patent document 1). Also in this LH disk, the reflectance of the crystalline region corresponding to the unrecorded state is reduced and the reflectance of the amorphous region corresponding to the recorded state is increased by the interference effect between the films constituting the multilayer film.

Patent document 1: JP patent No. 2512087 (pages 4 to 6, FIG. 1)

Non-patent document 1: proc. SPIE vol.3401, p.103, 1998

Disclosure of Invention

As described above, both HL and LH discs are now being studied in the field of optical discs of the phase change recording system and in the field of optical discs of the organic dye type. When these optical disks are mounted on a conventional recording/reproducing apparatus to record and reproduce information, the following problems arise due to the difference in the composition of the film. (1) The reflectivity of the HL disc differs from that of the LH disc in an unrecorded state (crystalline state in the case of phase change). (2) The relationship between the reflectance in the unrecorded state and the average reflectance after information recording is different between the HL disc and the LH disc. That is, depending on whether the optical disc is an HL disc or an LH disc, the relationship between the reflectance value and the magnitude of the area in the unrecorded state and the recorded state is different, and thus the level of the obtained reproduction signal is also different. Therefore, in the same recording and reproducing apparatus, there is a problem that information cannot be stably reproduced with high reliability for both the HL disc and the LH disc.

As a method for solving the above-described problem, there is considered a method in which information on which of an HL disc and an LH disc (hereinafter, also referred to as "type of disc") an optical disc mounted in a recording/reproducing apparatus is recorded in a control data area for storing physical format information of the optical disc, and based on the information, appropriate gain adjustment is performed to reproduce user information and the like.

Generally, control data of an optical disc is formed of embossed pits, and a control data area and a user data area are formed substantially adjacently. Thus, in the optical disk of the phase change recording system and the optical disk of the organic dye type, the phase change film, the protective film, the organic dye film, and the like are formed in not only the user data area but also the control data area, respectively. In such a conventional optical disc, even when information on the type of the optical disc is recorded in the control data area, the reflectance of the control data area changes depending on the type of the optical disc, and therefore, if gain adjustment is not performed, not only the control data but also the information on the type of the optical disc cannot be reproduced with high accuracy. Therefore, in an optical disc in which information on the type of the optical disc is recorded in the control data area, it is necessary to perform gain adjustment of a reproduction signal in accordance with the type of the optical disc and to reproduce the information on the type of the optical disc and the control data. However, there is no method for solving this problem, and there is no method for optimizing the gain according to the type of optical disc (HL disc or LH disc).

The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an optical disc, which can reproduce control data and user data quickly and with high reliability, for either an HL disc or an LH disc, and a recording and reproducing apparatus for the same.

The invention in its 1 st form provides an optical disc characterized by comprising a1 st area, the 1 st area recording user information; and a 2 nd area in which a plurality of marks extending in a radial direction of the optical disc are arranged in a track direction, and in which 2 nd area information relating to a reflectivity of the optical disc is recorded.

In an area near the inner periphery of an optical disc such as a general DVD, an area called bca (burst Cutting area) is provided. In the BCA, a plurality of marks extending along the radius of the optical disc are arranged in the track direction (a bar code-shaped mark group), and disc identification information such as the media ID and version information of the optical disc is recorded in this area. The barcode-like mark group is formed in a radial direction, for example, in a length of about 1 mm. In the optical disc of the present invention, information on the reflectivity of the optical disc is recorded in an area (2 nd area) where a barcode-like mark group such as a BCA is formed. In the following, the 1 st area of the optical disc of the present invention is also referred to as a "user data area", and the 2 nd area is also referred to as a "barcode area".

In the optical disc of the present invention, the information on the reflectance of the optical disc is preferably information indicating a relationship between the reflectance in an unrecorded state and the reflectance in a recorded state in the 1 st area. That is, in the barcode region of the optical disc of the present invention, it is preferable to record information indicating which of the HL disc and the LH disc the optical disc is. In the barcode area of the optical disc of the present invention, specific reflectance values in the recorded state and the unrecorded state of the user data area of the optical disc may be recorded.

Since the bar-code-like mark group formed in the bar-code area of the optical disc of the present invention is formed in a sufficient length (for example, about 1mm) in the radial direction, when reproducing information in the bar-code area, the bar-code information can be easily reproduced even if the position control in the radial direction of the light beam is not strictly performed. That is, the information of the barcode region can be reproduced by only the tracking method by the optical head without performing strict tracking control. Accordingly, the information on the reflectivity of the optical disc recorded in the barcode region can be easily obtained in a short time, and the gain adjustment of the reproduction signal can be performed quickly and appropriately based on the information on the reflectivity of the optical disc recorded in the barcode region. As a result, when information of the control data area and the user data area of the optical disc is reproduced immediately after the barcode area, it is not necessary to perform gain adjustment depending on the type of the optical disc, and the information can be reproduced quickly. Further, since the optimum amplification factor of the reproduction signal is obtained before the information of the control data area and the user data area is reproduced, the amplitude of the information of the control data area and the user data area and the amplitude of the servo signal for tracking can be sufficiently obtained regardless of the type of the optical disc, and information reproduction and tracking control with higher reliability can be performed.

The present invention is advantageous in that address information is recorded by forming a concentric or spiral guide groove in the 1 st area of an optical disc and deflecting the guide groove in the radial direction of the optical disc.

In the optical disc of the present invention, the user information is recorded in at least one of the guide groove and the guide groove interval, and it is preferable that the following relationship is satisfied between the track pitch TP in the 1 st region, the wavelength λ of the light beam used for recording and reproducing information, and the number NA of apertures of the condenser lens (lens):

0.35×(λ/NA)≤TP≤0.7×(λ/NA)

in order to increase the information capacity, a method of narrowing the track pitch is an effective method. However, for example, in an optical disc of the phase change recording method, if recording marks are recorded on very narrow tracks, a crystallization phenomenon (i.e., cross erase) is highly likely to occur in a part of the marks recorded on adjacent tracks (in an optical disc of an organic pigment type, if recording marks are recorded on very narrow tracks, a phenomenon (i.e., cross erase) in which a part of the marks adjacent to the tracks appears is likely to occur (in an optical disc of an organic pigment type), and it has been found from the verification experiment of the present inventors that, when the wavelength of laser light is represented by λ and the number of openings of a condenser lens (lens) of the laser light is represented by NA, if the track pitch TP is less than 0.35 × (λ/NA), for example, in an optical disc of the phase change recording method, the cross erase (λ/NA) increases, and if the track pitch TP is greater than 0.7 × (λ/NA), it is difficult to increase the capacity, for example, when it is found that the track pitch TP is set to a value in the range of 0.35 × (λ/NA) ≦ TP ≦ 0.7 × (λ/NA) in an optical disc of the phase-change recording method, cross erase (cross erase) can be significantly reduced even in the case of a narrow track pitch. Further, the present inventors have found that, in an organic dye type optical disc, cross erasure (cross erase) can be suppressed even at a narrow track pitch by setting the value of the track pitch TP so as to satisfy 0.35 × (λ/NA) ≦ TP ≦ 0.7 × (λ/NA).

In the optical disc of the present invention, the user information is preferably recorded in both of the guide groove and the space between the guide grooves. The recording density can be further improved by recording the user information in both the guide groove (groove) and the space between the guide grooves (non-pit portion (land)).

In the optical disk of the present invention, the optical disk has a recording layer formed of a phase change material containing Bi, Ge, and Te, and the recording layer is preferably provided in the 1 st region and the 2 nd region. Particularly, it is preferable that the composition ratio of Bi, Ge and Te satisfies ((GeTe)_x(Bi₂Te₃)_1-x)_1-yGe_y(wherein, x is 0.3-1, and y is 0-0.4) forming a recording layer. In addition, user data and information on the reflectivity of the optical disc are recorded on recording layers formed on the 1 st area (user data area) and the 2 nd area (barcode area), respectively.

In the recording layer formed of the Bi-Ge-Te phase change material, as disclosed in the conventional example (for example, JP-A-62-209741), a practical composition range is located between GeTe and Bi connected to a triangular composition diagram having Bi, Ge and Te as vertexes₂Te₃The area of (a). However, the inventors of the present invention found, through a proof experiment, that GeTe is in proportion to Bi₂Te₃By forming the recording layer with the phase change material in the region to which Ge is added supersaturatedly as compared with the connection line of (1), an optical disc having good signal quality and more excellent repetition durability can be obtained.

The inventors' hypothesis regarding this reason is as follows. In the Bi-Ge-Te based material, GeTe and Bi are present within the scope clear at present₂Te₃、Bi₂Ge₃Te₆、Bi₂GeTe₄、Bi₄GeTe₇The compound of (1). With composition of Bi-Ge-Te-based material but notSimilarly, when recrystallization occurs after melting of the recording layer, it is considered that the compound is recrystallized from the higher compound and from the outer edge of the melting region in the order of the melting points of Bi, Ge, Te and the above-mentioned compound. These substances were arranged in order of decreasing melting point as follows.

Ge: about 937 deg.C

GeTe: about 725 deg.C

Bi₂Ge₃Te₆: about 650 deg.C

Bii₂Te₃: about 590 deg.C

Bi₂GeTe₄: about 584 deg.C

Bi₂GeTe₄: about 564 deg.C

Te: about 450 deg.C

Bi: about 271 deg.C

That is, since Ge has the highest melting point, GeTe and Bi are considered to be in a triangular composition diagram having Bi, Ge and Te as vertexes₂Te₃In the recording layer formed by supersaturating and adding the Bi-Ge-Te phase change material of Ge to the connection line (a), Ge is likely to segregate at the outer edge portion of the melted region (recording mark) of the recording layer. Further, since Ge is present supersaturated in the outer edge portion of the molten region, the crystallization rate of the outer edge portion of the molten region is lowered, and as a result, recrystallization from the outer edge portion is suppressed, and therefore, it is considered that occurrence of "band" of recrystallization due to multiple rewriting can be suppressed. In addition, in addition to the above phenomenon, a material having a lower melting point is likely to segregate near the center of a track (recording mark), and thus the crystallization rate is increased, and good erasure performance can be obtained even at high-speed recording. However, if Ge is added excessively, the crystallization rate decreases, and it is important to appropriately add Ge.

In addition, it is not important to form a recording layer of a material that is not essential from the viewpoint of the shelf life of the recording marks in an amorphous stateThere are a plurality of amorphous phases, and the recording layer material has a high crystallization temperature, and the activation energy is large when the amorphous portion is crystallized. The present inventors have found that Ge of a triangular composition diagram having Bi, Ge and Te as vertexes₅₀Te₅₀The nearby components satisfy the above conditions. One reason for this is considered to be that GeTe has a high crystallization temperature of 200 ℃ as disclosed in the previous examples (for example, JP-A-62-209741), with the composition approaching Bi₂Te₃The crystallization temperature is reduced.

In addition, the inventors found out from the verification experiment that Ge is present₅₀Te₅₀In the vicinity, the amorphous state is hard to change even after long-term storage, and good erasing characteristics can be obtained. However, if the GeTe amount is too large, the crystallization rate decreases and high-speed recording becomes impossible, and if Bi is present₂Te₃When the amount is too large, the crystallization temperature is lowered, and the shelf life is deteriorated. It is thus known that the most suitable composition for the recording layer material is in Ge₅₀Te₅₀Adding proper amount of Bi₂Te₃And a Bi-Ge-Te-based material having a region with excessive Ge is used. Specifically, the inventors have found that the composition ratio of Bi, Ge and Te for the recording layer satisfies ((GeTe)_x(Bi₂Te₃)_1-x)_1-yGe_y(wherein x is 0.3. ltoreq. x < 1, and y is 0. ltoreq. y 0.4). In addition, Bi is provided so as to be adjacent to the recording layer₂Te₃The effect of suppressing recrystallization can be further improved by forming a layer with a core such as SnTe or PbTe. In addition, in the optical disk of the present invention, if the recording layer material maintains the relationship of the above-described composition ranges, even in the case where impurities are mixed, if the atomic% of the impurities is within 1%, the effects of the present invention do not disappear.

In the optical disk of the present invention, the optical disk has a recording layer containing an organic dye, and the recording layer is preferably provided in the 1 st area and the 2 nd area.

The invention provides a recording/reproducing device of the CD, in the area that a plurality of marks extending along the radial direction of the CD arrange along the track direction, record the information related to reflectance of the CD, characterized by that the device includes the optical head, the optical head irradiates the light beam to the CD; a signal processing circuit for reproducing information based on the reproduction signal detected by the optical head; a gain adjustment circuit that adjusts an amplification factor of the reproduction signal; a judgment circuit for identifying the type of the optical disc based on information relating to a change in the reflectivity of the optical disc, the information relating to the change in the reflectivity being information in which the reflectivity changes from a low value to a high value or in which the reflectivity changes from a high value to a low value; the gain adjustment circuit adjusts the amplification factor of the reproduction signal based on the determination result of the determination circuit.

The information on the reflectivity of the optical disc is information indicating a relationship between the reflectivity in an unrecorded state and the reflectivity in a recorded state in a user information area within the optical disc.

The invention provides a method for reproducing an optical disc, in which information relating to the reflectivity of the optical disc is recorded in a region where a plurality of marks extending in the radial direction of the optical disc are arranged in the track direction, the method comprising the steps of: irradiating the region with a light beam; reproducing information relating to the reflectivity of the optical disc based on the reflected light from the area; determining an amplification factor of a reproduction signal based on the reproduced information on the reflectance of the optical disc; information recorded in an area other than the area is reproduced according to the determined amplification factor of the reproduction signal. The information on the reflectance of the optical disc is information indicating a relationship between the reflectance in an unrecorded state and the reflectance in a recorded state in the user information area in the optical disc, and the information on the change in the reflectance of the optical disc is information indicating a change in the reflectance from a low value to a high value or a change in the reflectance from a high value to a low value.

The present invention also provides a method for manufacturing an optical disc, characterized in that the manufacturing method comprises the steps of: in the optical disk, a recording film is provided; recording the mark group by adjusting the light intensity according to the recorded/unrecorded reflectivity variation information; irradiating a recording film in a predetermined area of the optical disc with a light beam to form a mark group in which a plurality of marks extending in a radial direction are arranged in a track direction; the mark group is formed as information related to the reflectivity of the optical disc. The information on the reflectance of the optical disc is information indicating a relationship between the reflectance of an unrecorded area of the user information area in the optical disc and the reflectance in a recorded state, and the information on the change in the reflectance of the optical disc is information indicating a change in the reflectance from a low value to a high value or a change in the reflectance from a high value to a low value.

In the manufacturing method of the present invention, it is preferable that the recording film is formed of a phase-change material, and the step of forming the mark group includes adjusting the intensity of the light beam based on a relationship between a reflectance in an unrecorded state and a reflectance in a recorded state of the user information area, thereby recording information indicating the relationship between the reflectance in the unrecorded state and the reflectance in the recorded state of the user information area as the mark group in the recording film.

As a method for forming a bar code-like mark group extending in a radial direction by irradiating a recording film in a predetermined area (bar code area) of an optical disc of a phase change material recording system with a light beam, there is a method for etching the recording film formed on the optical disc by irradiating a high-power light beam on a predetermined portion of the bar code area in accordance with information to be recorded; a method of recording a barcode-like mark group by providing a recording film formed of a phase-change material on a barcode region, adjusting the intensity of a light beam in accordance with information, irradiating the recording film with a light beam, and forming a crystalline region and an amorphous region on the recording film in the barcode region. In the manufacturing method of the present invention, it is particularly preferable to form a bar code-like mark group by the latter method, which will be described further below.

The recording film formed of the phase-change material is formed by thermal spraying or the like, and the formed state is amorphous. Therefore, when a barcode-like mark group is formed in a state after the recording film is formed, it is preferable to crystallize only a predetermined portion of information by using the amorphous state (recording state) at that time. The forming method may also be performed by an apparatus employed when an initial crystallization process (also simply referred to as "initialization") is performed on the entire surface of the optical disc. Alternatively, the initialization process may be performed in a region other than the barcode region, and then the barcode-like mark group may be recorded in the barcode region.

In the method of forming a bar code region according to the present invention, when forming a bar code-shaped mark group, the intensity adjustment pattern of the light beam is reversed according to the type of the optical disk (HL disk or LH disk), whereby information of the reflectance pattern having the same polarity is formed regardless of the type of the optical disk.

Fig. 3 shows an example of a method for forming a barcode region of an optical disc of the phase-change-material recording system according to the present invention. For example, fig. 3(c) shows an intensity adjustment pattern of laser light irradiated to the HL disc when information of the reflectance pattern shown in fig. 3(a) is recorded in the barcode region. In the HL disc, as shown in fig. 3(c), a portion intended to have a high reflectance (a portion in an unrecorded state) is irradiated with a light beam at an intensity that achieves crystallization (600mW in fig. 3(c)) to achieve crystallization as shown in an area H in fig. 3(a), and an amorphous state is maintained in a portion intended to have a low reflectance (a portion in a recorded area) as shown in an area L in fig. 3(a) by not irradiating a light beam or irradiating a light beam at a weak intensity (150mW in fig. 3 (c)). In the HL disc, a bar-code-like mark group corresponding to the reflectance pattern shown in fig. 3(a) can be formed by irradiating a light beam with the intensity adjustment pattern shown in fig. 3 (c).

On the other hand, fig. 3(b) shows an intensity adjustment pattern of a light beam irradiated when barcode information of a reflectivity pattern as shown in fig. 3(a) is recorded in the LH disk. In the LH disk, as shown in fig. 3(b), a portion intended to have a high reflectance (a portion in a recorded state) is not irradiated with a light beam or irradiated with a light beam of a weak intensity (150mW in fig. 3(b)) as in the region H in fig. 3(a), and an amorphous state is maintained, and crystallization is performed by a light beam of an intensity to achieve crystallization (600mW in fig. 3(b)) as in the region L in fig. 3(a) at a portion intended to have a low reflectance (a portion in an unrecorded state). In the LH disk, by irradiating a light beam with the intensity adjustment pattern as shown in fig. 3(b), a barcode-like mark group corresponding to the reflectance pattern as shown in fig. 3(a) can be formed.

As is clear from fig. 3, when a bar code-shaped mark group is formed on a recording film made of a phase-change material, as shown in fig. 3(b) and (c), the patterns for adjusting the intensity of the light beam are reversed in both the HL disc and the LH disc, and thus the same information on the reflectance pattern can be formed in both the HL disc and the LH disc (fig. 3 (a)). If information of the barcode region where information is recorded by such a method is reproduced, both HL discs and LH discs can be reproduced with values within the same reflectance range. Therefore, when reproducing the information in the barcode region, it is not necessary to perform gain adjustment or the like depending on the type of the optical disc, and the information in the barcode region can be reproduced quickly and with high reliability.

In the manufacturing method of the present invention, it is preferable that the recording layer contains an organic dye, and the step of forming the mark group includes adjusting the intensity of the light beam based on a relationship between a reflectance in an unrecorded state and a reflectance in a recorded state of the user information area, thereby recording information indicating the relationship between the reflectance in the unrecorded state and the reflectance in the recorded state of the user information area as the mark group in the recording film.

As a method of forming a bar code-like mark group extending in a radial direction by irradiating a recording film in a predetermined area (bar code area) of an organic dye type optical disc with a light beam, there is a method of irradiating a high-power light beam in a predetermined portion of the bar code area in accordance with information to be recorded, and etching the recording film formed on the optical disc, as in the case of the optical disc of the phase change material recording system; a method of recording a barcode-like mark group by providing a recording film containing an organic dye on a barcode region, adjusting the intensity of a light beam in accordance with information, irradiating the recording film with a light beam, and recording on the recording film in the barcode region. In the manufacturing method of the present invention, when manufacturing an organic dye type optical disc, it is particularly preferable to form a bar code-like mark group by the latter method, which will be further described below.

The recording film containing the organic dye is formed by spin coating (spincoat) or the like, and the formed state corresponds to an unrecorded state. Therefore, when the bar code-like mark group is formed in a state after the recording film is formed, it is preferable that the recording state is formed by recording only a predetermined portion in accordance with the information.

In the method of forming a bar code region according to the present invention, when forming a bar code-shaped mark group, the intensity adjustment pattern of the light beam is reversed according to the type of the optical disk (HL disk or LH disk), and information of the reflectance pattern having the same polarity regardless of the type of the optical disk is formed.

Fig. 6 shows an example of a method for forming a barcode region of an organic dye type optical disc according to the present invention. For example, fig. 6(b) shows an intensity adjustment pattern of a laser beam irradiated to the HL disc when information of the reflectance pattern as shown in fig. 6(a) is recorded in the barcode region. In the HL optical disc, a portion intended to have a high reflectance (a portion in an unrecorded state) is not irradiated with a light beam or a light beam of a weak intensity (0.5 mW in fig. 6 b) which does not change in a recording film, as in an area H in fig. 6 b, so as to maintain the unrecorded state, and a portion intended to have a low reflectance (a portion in a recorded state) is irradiated with a light beam of a recording intensity (10mW in fig. 6 b), as in an area L in fig. 6 a, so as to achieve the recorded state. In the HL disc, a bar-code-shaped mark group corresponding to the reflectance pattern shown in fig. 6(a) can be formed by irradiating the HL disc with a light beam according to the intensity adjustment pattern shown in fig. 6 (b).

On the other hand, fig. 6(c) shows an intensity adjustment pattern of the light beam irradiated when the barcode of the reflectance pattern shown in fig. 6(a) is recorded on the LH disk. In the LH disk, as shown in fig. 6(c), a portion intended to have a high reflectance (a portion in a recorded state) is irradiated with a light beam having an intensity (10mW in fig. 6(c)) for realizing recording as in the region H in fig. 6(a) so as to be in the recorded state, and the portion intended to have a low reflectance (a portion in an unrecorded state) as in the region L in fig. 6(a) is not irradiated with the light beam or is irradiated with a light beam having a weak intensity (0.5 mM in fig. 6(c)) which does not change in the recording film so as to be maintained in the unrecorded state. In the LH disk, a bar-code-shaped mark group corresponding to the reflectance pattern shown in fig. 6(a) can be formed by irradiating a light beam with the intensity adjustment pattern shown in fig. 6 (c).

As is clear from fig. 6, when a barcode-like mark group is formed on a recording film containing an organic dye, the intensity adjustment patterns of the light beam are reversed in both the HL disc and the LH disc as shown in fig. 6(b) and 6(c), and thus the same information on the reflectance pattern can be formed in both the HL disc and the LH disc (fig. 6 (a)). If information of the barcode region of the information recorded by such a forming method is reproduced, both the HL disc and the LH disc can be reproduced with values within substantially the same reflectance range. Therefore, when reproducing the information in the barcode region, it is not necessary to perform gain adjustment or the like depending on the type of the optical disc, and the information in the barcode region can be reproduced quickly and with high reliability.

Effects of the invention

According to the optical disc of the present invention, since information on the optical disc is recorded in the barcode region, it is easy to obtain the information without performing strict tracking control and gain adjustment, and thus it is possible to quickly perform gain adjustment of a reproduction signal appropriately. Therefore, when detecting information of the control data area and the user data area of the optical disc and a servo signal for tracking, the optical disc can be reproduced quickly regardless of the type of the optical disc, and can be detected in accordance with a reproduction signal having a sufficient amplitude, so that reproduction can be performed with higher reliability.

According to the recording/reproducing apparatus and the reproducing method of the present invention, information on the reflectance of the optical disc recorded in the barcode region of the optical disc is detected without performing strict tracking control and gain adjustment, the type of the optical disc is determined based on the information, and an appropriate amplification factor of the reproduced signal is determined. Therefore, when detecting information in the control data area and the user data area of the optical disc and a servo signal for tracking, the information can be reproduced quickly regardless of the type of the optical disc, and the information can be reproduced with higher reliability by detecting a reproduction signal having a sufficient amplitude.

In addition, according to the method of manufacturing an optical disc of the present invention, when a barcode-like mark is formed on a recording layer formed of a phase change material or a barcode-like mark is formed on a recording layer containing an organic pigment, the patterns of intensity adjustment of the light beam are reversed according to the type of the optical disc as shown in fig. 3 or 6, and thus, information of the same reflectance pattern can be formed in both the HL disc and the LH disc. Therefore, in the optical disk manufactured by the manufacturing method of the present invention, if information in the barcode region is reproduced, the information can be reproduced with a value in the substantially same reflectance range regardless of the type of the optical disk (HL disk or LH disk). As a result, it is possible to obtain an optical disc in which, when reproducing information in the barcode region, gain adjustment is not necessary depending on the type of the optical disc, and information in the barcode region can be reproduced quickly and with high reliability.

Description of the drawings:

fig. 1 is a schematic plan view of an optical disc manufactured according to embodiment 1;

fig. 2 is a schematic cross-sectional view of an optical disc manufactured according to embodiment 1;

fig. 3 is a diagram showing a state in which a reflectivity pattern of information in a barcode region C of an optical disc manufactured according to embodiments 1and 2 and intensity adjustment of laser light for forming the pattern are shown, fig. 3(a) shows the reflectivity pattern, fig. 3(b) shows the intensity adjustment pattern of laser light for an LH disc using a phase change recording film, and fig. 3(C) shows the intensity adjustment pattern of laser light for an HL disc using a phase change recording film;

FIG. 4 is a schematic cross-sectional view of an optical disk made in accordance with embodiment 2;

FIG. 5 is a schematic configuration diagram of a recording/reproducing apparatus according to the present invention;

fig. 6 is a diagram showing a state of a reflectivity pattern of information of the barcode region C of the optical disc manufactured according to the 3 rd and 4 th embodiments and intensity adjustment of laser light for forming the pattern, fig. 6(a) is the reflectivity pattern, fig. 6(b) is the intensity adjustment pattern of laser light of an HL disc using an organic pigment recording film, and fig. 6(C) is the intensity adjustment pattern of laser light of an LH disc using an organic pigment recording film;

fig. 7 is a schematic cross-sectional view of an optical disc manufactured according to embodiment 3;

fig. 8 is a schematic cross-sectional view of an optical disc manufactured according to embodiment 4.

Examples

The following describes embodiments of an optical disc and a recording/reproducing apparatus thereof according to the present invention, but the present invention is not limited thereto.

Example 1

(Structure of optical disk)

In example 1, an HL disc as a phase change recording method of an optical disc was produced. Fig. 1 shows a schematic plan view of an optical disc produced according to the present example. As shown in fig. 1, the optical disc 10 of the present example is provided with a user data area a for recording user data, a control data area B for recording physical format information of the optical disc 10, and a barcode area C for recording information by a barcode-like mark group (also referred to as "barcode information") formed by arranging a plurality of marks extending in the radial direction along a track, in this order from the outer peripheral side.

The user data area A is disposed in a region of the optical disc 10 having a radius of about 23.8 to 58.5mm, and the user data area A has a spiral shape in which grooves having a track pitch of 0.68 μm and a depth of 45nm are formed. In addition, in the user data area a, a header recording portion (not shown) including address information is formed by offsetting the grooves in the radial direction.

The control data area B is disposed in an area of the optical disc 10 having a radius of about 23.3 to 23.8mm, and the physical format information of the optical disc 10 is formed of 1 to 7 adjusted pit (pit) rows having a track pitch of 0.68 μm and a shortest mark length of 0.4 μm. In addition, between the user data area a and the control data area B, a connection (connection) area (not shown) of about 10 μm is provided.

The barcode region C is provided in a region of the optical disc 10 having a radius in a range of about 22.2 to 23.2mm, and not only identification information of the optical disc such as a medium ID and version information but also information indicating a relationship between a reflectance in an unrecorded state and a reflectance in a recorded state of the user data region a of the optical disc 10 is recorded in the barcode region C. Specifically, since the optical disc 10 produced in this example is an HL disc, information that reduces the reflectance due to recording is recorded in a predetermined region of the barcode region C. In addition, in the barcode region C, values of the reflectance in the unrecorded state and the reflectance in the recorded state of the user data region a may be recorded as information on the reflectance of the optical disk. A method of recording information in the barcode area C will be described later.

(method for manufacturing optical disk)

Fig. 2 shows a schematic cross-sectional view of an optical disc made in accordance with this example. The optical disk 10 produced according to this example has a structure in which, as shown in fig. 2, a protective layer 2, a1 st thermally stable layer 3, a recording layer 4, a 2 nd thermally stable layer 5, an intermediate layer 6, a thermal diffusion layer 7, a UV resin layer 8, and a transparent substrate 9 are stacked in this order on a substrate 1. In addition, in this example, the above-described layers are formed on the user data area a, the control data area B, and the barcode area C of the optical disc 10. The following describes a method of manufacturing the optical disk of this example.

First, a substrate 1 made of polycarbonate (poly-carbonate) and having a diameter of 120mm and a thickness of 0.6 was manufactured by injection molding using a stamper (stamp). In this case, a spiral groove having a track pitch of 0.68 μm and a depth of 45nm was formed in the user data region A, and a pit row having a track pitch of 0.68 μm and a shortest mark length of 0.4 μm was formed in the control data region B.

Next, a protective layer 2 (ZnS) was formed on the substrate 1 by thermal spraying to a film thickness of 58nm₈₀(SiO₂)₂₀. Next, Ge was deposited as a1 st thermally stable layer 3 on the protective layer 2 by thermal spraying to a film thickness of 1nm₈Cr₂N (relative ratio). Further, Bi as a recording layer 4 was formed on the 1 st thermally stable layer 3 by thermal spraying in a thickness of 13nm₃Ge₄7Te₅₀. Then, Ge was formed as a 2 nd thermally stable layer 5 on the recording layer 4 by thermal spraying in a film thickness of 1nm₈Cr₂N (relative ratio). Next, on the 2 nd thermally stable layer 5, an intermediate layer 6 (ZnS) was formed by thermal spraying to have a film thickness of 48nm₅₀(SiO₂)₅₀. Then, Al as a thermal diffusion layer 7 was formed on the intermediate layer 6 by thermal spraying to a film thickness of 150nm₉₉Ti₁。

Then, an ultraviolet curable resin as a UV resin layer 8 was applied to the thermal diffusion layer 7, and a transparent substrate 9 made of polycarbonate (poly-carbonate) having a thickness of 0.6mm was further placed thereon. Then, the transparent substrate 9 is attached to the UV resin layer 8 by irradiating ultraviolet rays through the transparent substrate 9 to cure the ultraviolet curing resin. The phase-change recording optical disc 10 shown in fig. 2 is obtained by the above-described manufacturing method.

In the optical disk 10 produced according to the present example, the reflectance of the unrecorded state (crystalline state) portion was 18%, and the reflectance of the recorded state (amorphous state) portion, that is, the recording mark portion was 5%.

(method of Forming Bar code region C)

In the optical disk 10 manufactured according to the present example, the barcode region C is formed in the region having a width of 1mm in the range of the radius of the optical disk of about 22.2 to 23.2mm as described above. The bar code-like mark group formed in the bar code region C is configured as follows using an initialization processor (not shown). However, in this example, before the initial (crystallization) treatment is performed on the entire surface of the optical disk, a barcode-like mark group is formed inside the barcode region C. Further, after only the user data area a and the control data area B are initially processed, a barcode-like mark group may be recorded in the barcode area C.

The optical disk manufactured in this example was mounted in an initial processor, rotated at 2400rpm, and irradiated with a laser beam having a wavelength of 810 nm. At this time, the spot (spot) of the laser beam is focused so as to form a shape in which the length in the radial direction of the optical disc is about 50 μm and the length (width) in the track direction is about 1 μm, and the laser beam is irradiated to a predetermined position on the barcode region C in accordance with the information recorded in the barcode region C. However, the power of the laser light irradiated on the optical disk is adjusted between 600 to 150 mW.

Fig. 3 shows a pattern of intensity adjustment of the laser beam when the barcode-like mark group is formed in the barcode region C. In fig. 3, fig. 3(b) and 3(c) show the state of intensity adjustment of the laser light when the barcode information of the reflectance pattern shown in fig. 3(a) is recorded. Fig. 3(b) is a diagram showing an intensity adjustment pattern of the laser beam of the LH disk, and fig. 3(c) is a diagram showing an intensity adjustment pattern of the laser beam of the HL disk. Since the optical disk produced in this example was an HL disk, the intensity of the laser beam was adjusted as shown in fig. 3(c), and the barcode information was recorded. In the barcode region C, the entire recording layer of the optical disc is in a state after thermal spraying, that is, an amorphous state, before information is recorded. In this example, the region irradiated with the high laser power (600Mw) is heated to be in a crystalline state, and the barcode information is recorded by the change in the reflectance of the region.

In the HL disc, as shown in fig. 3(c), a portion intended to have a high reflectance as in the region H in fig. 3(a) is irradiated with a light beam having an intensity (600Mw in fig. 3(c)) to crystallize the region, and a portion intended to have a low reflectance (a portion in a recorded state) as in the region L in fig. 3(a) is irradiated with a light beam having a weak intensity (150Mw in fig. 3(c)) to maintain an amorphous state. By adjusting the beam intensity in this manner, a bar code-like mark group corresponding to the reflectance pattern shown in fig. 3(a) is formed.

Then, while the longitudinal direction of the laser spot (spot) is made substantially coincident with the radius of the optical disk, the laser spot (spot) is moved to the outside in the radial direction every 1 rotation of the optical disk. At this time, the moving amount of the laser spot (spot) per one turn is 36 μm. As shown in the barcode region C in fig. 1, the recording marks forming the barcode-like mark group are emitted in the same pattern with respect to the center of the optical disc, and the pattern of light adjustment of the laser light (the timing of laser light irradiation) is synchronized with information to be recorded every 1 rotation of the optical disc. In this example, the optical disk was rotated about 30 revolutions, the length in the radial direction was about 1mm, and recording marks having a width of about 1 μm in the multi-track direction were arranged in the track direction, thereby forming a bar-code-like mark group in the bar-code region C as shown in fig. 1.

Example 2

In example 2, an LH disc as a phase change recording method of an optical disc was produced. The schematic plan view of the optical disk produced in this example is the same as that of fig. 1, and in the barcode region C, not only identification information of the optical disk such as media ID and version information but also information indicating the relationship between the reflectance in the unrecorded state and the reflectance in the recorded state of the user data region a of the optical disk are recorded. Specifically, since the optical disc manufactured according to this example is an LH disc, information increased in reflectance by recording is recorded in a predetermined region of the barcode region C. In addition, in the barcode region C, values of the reflectance in the unrecorded state and the reflectance in the recorded state of the user data region a may be recorded as information on the reflectance of the optical disk. A method of recording information in the barcode area C will be described later.

(method for manufacturing optical disk)

Fig. 4 shows a schematic cross-sectional view of an optical disc manufactured according to this embodiment. The optical disk 20 produced according to this example has a structure in which, as shown in fig. 4, a1 st protective layer 21, a 2 nd protective layer 22, a 3 rd protective layer 23, a1 st thermally stable layer 3, a recording layer 4, a 2 nd thermally stable layer 5, an intermediate layer 6, a thermal diffusion layer 7, a UV resin layer 8, and a transparent substrate 9 are stacked in this order on a substrate 1. In addition, in this embodiment, the above-described layers are formed on the user data area a, the control data area B, and the barcode area C of the optical disc 20. The method of manufacturing the optical disc of the present embodiment is described below. However, the substrate 1 is fabricated in the same manner as in embodiment 1.

First, a (ZnS) layer 21 was formed as a first protective layer 1 on the substrate 1 by thermal spraying to a film thickness of 50nm₈₀(SiO₂)₂₀. Next, Al as a 2 nd protective layer 22 was formed on the 1 st protective layer 21 by thermal spraying to a film thickness of 40nm₂O₃. Next, a (ZnS) layer of a 3 rd protective layer 23 was formed on the 2 nd protective layer 22 by thermal spraying to a film thickness of 20nm₈₀(SiO₂)₂₀. That is, in the optical disk of the present embodiment, the protective layer has a 3-layer structure. In this example, since the protective layer has a 3-layer structure, the reflectance of the crystalline region corresponding to the unrecorded state is reduced and the reflectance of the amorphous region corresponding to the recorded state is increased by the interference effect between the layers。

Next, on the 3 rd protective layer 23, a1 st thermally stable layer 3 of Ge was formed by thermal spraying to a film thickness of 2nm₈Cr₂N (relative ratio). Then, Bi as a recording layer 4 was formed on the 1 st thermally stable layer 3 by thermal spraying in a film thickness of 10nm₃Ge₄₇Te₅₀. Then, Ge as a 2 nd thermally stable layer 5 was formed on the recording layer 4 by thermal spraying to a film thickness of 2nm₈Cr₂N (relative ratio). Next, on the 2 nd thermally stable layer 5, an intermediate layer 6 (ZnS) was formed by thermal spraying to have a film thickness of 35nm₅₀(SiO₂)₅₀. Then, Al as a thermal diffusion layer 7 was formed on the intermediate layer 6 by thermal spraying to a film thickness of 150nm₉₉Ti₁。

Then, an ultraviolet curable resin as a UV resin layer 8 was applied to the thermal diffusion layer 7, and a transparent substrate 9 made of polycarbonate (poly-carbonate) having a thickness of 0.6mn was further placed thereon. Then, the transparent substrate 9 is attached to the UV resin layer 8 by irradiating ultraviolet rays through the transparent substrate 9 to cure the ultraviolet curing resin. The phase-change recording optical disc 20 shown in fig. 4 is obtained by the above-described manufacturing method.

In the optical disc 20 manufactured according to this example, the reflectance of the unrecorded state (crystalline state) portion was 5%, and the reflectance of the recorded state (amorphous state) portion, that is, the recording mark portion was 16%.

(method of Forming Bar code region C)

In the optical disk manufactured according to the present embodiment, the barcode region C is formed in the same manner as in embodiment 1 except that the pattern of intensity adjustment of the laser light when the bar-shaped code mark group is formed in the barcode region C is changed. A method of forming the barcode area C of the optical disc manufactured according to the present embodiment will be described below.

Also in this example, similarly to embodiment 1, adjustment of the intensity of the laser light at the time of recording the barcode information of the reflectance pattern as shown in fig. 3(a) is considered. The optical disc manufactured according to this embodiment is an LH disc. The intensity of the laser beam was adjusted as shown in fig. 3(b), and barcode information was recorded. In the barcode region C, the entire surface of the recording layer of the optical disc is in a state after thermal spraying, that is, an amorphous state, before information is recorded. In this example, the region irradiated with a high laser power (600mW) was heated to be in a crystalline state, and the reflectance of the region was changed, thereby recording information.

In the LH disk, as shown in fig. 3 b, a portion intended to have a high reflectance (a portion in a recorded state) is irradiated with a laser beam of a weak intensity (150mW in fig. 3 b) as in the region H in fig. 3 a to maintain an amorphous state, and a portion intended to have a low reflectance (a portion in an unrecorded state) as in the region L in fig. 3 a is irradiated with a laser beam of an intensity capable of realizing crystallization (600mW in fig. 3 b) to realize crystallization. By adjusting the laser intensity in this manner, a bar-code-like mark group corresponding to the reflectance pattern shown in fig. 3(a) is formed on the LH disk similarly to the HL disk.

As is clear from fig. 3, when the optical disc is an LH disc as in the present embodiment, the intensity adjustment pattern of the laser beam (fig. 3(b)) is made to be a pattern opposite to the intensity adjustment pattern of the laser beam (fig. 3(c)) of the HL disc (embodiment 1), whereby information of the same reflectance pattern can be formed (fig. 3 (a)). If the information in the barcode region where the information is recorded is reproduced by such a method, the information can be reproduced with a value in the same reflectance range regardless of the type of the optical disc (HL disc or LH disc). Therefore, when reproducing the information in the barcode region C, it is not necessary to perform gain adjustment or the like depending on the type of the optical disc, and the information in the barcode region C can be reproduced quickly and with high reliability.

Example 3

(Structure of optical disk)

In example 1, an HL disc containing an organic pigment recording film was produced as an optical disc. The schematic plan view of the optical disk produced in this embodiment is similar to fig. 1and 2, and as shown in fig. 1, a user data area a for recording user data, a control data area B for recording physical format information of the optical disk, and a barcode area C for recording information by a barcode-like mark group (also referred to as "barcode information") formed by arranging a plurality of marks extending in a radial direction along a track are provided in this order from the outer peripheral side.

The user data area A is arranged in the area of the radius range of 23.8-58.5 mm of the optical disk, and the user data area A is in a spiral shape and is provided with grooves with the track pitch of 0.4 mu m and the depth of 80 nm. In addition, in the user data area a, a header recording portion (not shown) including address information is formed by offsetting the grooves in the radial direction.

The control data area B is arranged in the area with the radius of 23.3-23.8 mm, the physical format information of the optical disk is formed by 1-7 adjusted pit rows with the track pitch of 0.68 μm and the shortest mark length of 0.4 m. In addition, a connection region (not shown) of about 10 μm is provided between the user data region a and the control data region B.

The barcode region C is provided in a region of the optical disc having a radius of about 22.2 to 23.2mm, and not only identification information of the optical disc such as a medium ID and version information but also information indicating a relationship between a reflectance in an unrecorded state and a reflectance in a recorded state of the user data region A of the optical disc is recorded in the barcode region C. Specifically, since the optical disc manufactured according to this embodiment is an HL disc, information that reduces the reflectance due to recording is recorded in a predetermined region of the barcode region C. In addition, in the barcode region C, values of the reflectance in the unrecorded state and the reflectance in the recorded state of the user data region a may be recorded as information on the reflectance of the optical disk. A method of recording information in the barcode area C will be described later.

(method for manufacturing optical disk)

Fig. 7 shows a schematic cross-sectional view of the organic dye optical disk fabricated according to this example. The optical disc 30 manufactured according to this example has a structure in which, as shown in fig. 7, a base layer 32, an organic dye recording layer 34, a thermal diffusion layer 7, a UV resin layer 8, and a transparent substrate 9 are stacked in this order on a substrate 1. In addition, in this embodiment, the above-described layers are formed on the user data area a, the control data area B, and the barcode area C of the optical disc 30. The following describes a method of manufacturing the optical disk of this example.

First, a substrate 1 made of polycarbonate (poly-carbonate) and having a diameter of 120mm and a thickness of 0.6 was manufactured by injection molding using a stamper (stamp). In this case, a spiral groove (groove) having a track pitch of 0.4 μm and a depth of 80nm is formed in the user data region A, and a pit row having a track pitch of 0.68 μm and a shortest mark length of 0.4 μm is formed in the control data region B.

Next, on the substrate 1, a base layer 32 (ZnS) was formed by thermal spraying to a film thickness of 20nm₈₀(SiO₂)₂₀. Next, an organic dye recording layer 34 containing an organic dye represented by the following chemical formula (1) in a quinolone (carbostyril) compound is formed on the underlayer 32. Specifically, 0.5g of an organic dye represented by the following chemical formula (1) was dissolved in 40g of octafluoropentanol (octafluoropentanol), subjected to ultrasonic dispersion treatment at a temperature of 40 ℃ for 30 minutes, and then filtered through a 0.2 μm filter paper. Subsequently, the filtrate was spin-coated (spincoat) on the substrate 1 at 1300rpm, and dried in an oven at 80 ℃ for 30 minutes to form the organic dye recording layer 34. The organic dye recording layer 34 had a film thickness of 80 nm. Next, Agl as the thermal diffusion layer 7 was formed on the organic dye recording layer 34 by thermal spraying in a film thickness of 150nm₉₇Ru₂Cu₁。

Chemical formula 1

Next, an ultraviolet curable resin was applied as a UV resin layer 8 on the thermal diffusion layer 7, and a transparent substrate 9 made of polycarbonate (poly-carbonate) having a thickness of 0.6mn was further placed thereon. Then, the transparent substrate 9 is attached to the UV resin layer 8 by irradiating ultraviolet rays through the transparent substrate 9 to cure the ultraviolet curing resin. The organic dye type optical disc 30 shown in fig. 7 is obtained by the above-described manufacturing method.

In addition, in the optical disk manufactured according to the present example, the reflectance of the portion in the unrecorded state of the mirror (mirror) region having no groove or pit was 40%, and the reflectance of the portion in the recorded state, that is, the recorded mark portion was 10%.

(method of Forming Bar code region C)

In the optical disk manufactured according to this embodiment, as described above, the barcode region C is formed in the region having a width of 1mm within the range of about 22.2 to 23.2mm in the radius of the optical disk. The mark group of the bar code formed in the bar code region C is formed as follows using a bar code former (not shown) using a laser beam having a wavelength of 405 nm.

The optical disk manufactured according to this example was set in a barcode generator, and the optical disk was rotated at 2400rpm, and irradiated with a laser beam having a wavelength of 405 nm. At this time, the spot (spot) of the laser beam is focused so as to form a shape of about 0.6 μm in both the length in the radial direction and the length (width) in the track direction of the optical disc, and the laser beam is irradiated at a predetermined position on the barcode region C in accordance with the information recorded in the barcode region C. However, the power of the laser light irradiated on the optical disk is adjusted to 10 to 0.5 mW.

Fig. 6 shows a pattern of intensity adjustment of the laser beam when the barcode-like mark group is formed in the barcode region C. In fig. 6, fig. 6(b) and 6(c) show the state of intensity adjustment of the laser beam when the barcode information of the reflectance pattern as shown in fig. 6(a) is recorded. Fig. 6(b) is a diagram showing an intensity adjustment pattern of laser light of an HL disc, and fig. 6(c) is a diagram showing an intensity adjustment pattern of laser light of an LH disc. Since the optical disc produced in this example was an HL disc, the intensity of the laser beam was adjusted as shown in fig. 6(b), and the barcode information was recorded. In the barcode area C, the entire recording layer of the optical disc is in an unrecorded state before information is recorded. Then, in this example, the region irradiated with the high laser power (10Mw) is heated to be in a recording state, and the reflectance of the portion is changed, whereby the barcode information is recorded.

In the HL disc, as shown in fig. 6(b), a portion intended to have a high reflectance (a portion in an unrecorded state) is irradiated with a light beam of a weak intensity (0.5 mW in fig. 6(b)) as shown in the region H in fig. 6(a) to maintain the unrecorded state, and a portion intended to have a low reflectance (a portion in a recorded state) as shown in the region L in fig. 6(a) is irradiated with a light beam of an intensity to achieve recording (10mW in fig. 6(b)) to establish the recorded state. By adjusting the beam intensity in this manner, a bar code-like mark group corresponding to the reflectance pattern as shown in fig. 6(a) is formed.

Then, while the longitudinal direction of the laser spot (spot) is made to substantially coincide with the radial direction of the optical disk, the laser spot (spot) is moved to the outer side in the radial direction every 1 rotation of the optical disk. At this time, the movement amount of the laser spot (spot) per turn is 0.6 μm or less. Further, as shown in a barcode area C in fig. 1, a pattern of laser adjustment (timing of laser light irradiation) is synchronized with information to be recorded every 1 rotation of the optical disc so that each recording mark of a mark group forming a barcode shape is formed radially with the same width with respect to the center of the optical disc. In this embodiment, the optical disk is rotated about 1700 revolutions, the length in the radial direction is about 1mm, and a plurality of recording marks having a width in the track direction of about 1 μm are arranged in the track direction, thereby forming a barcode-like mark group in the barcode region C as shown in fig. 1.

Example 4

(Structure of optical disk)

In example 4, an LH disk having an organic pigment recording layer was produced as an optical disk. The schematic plan view of the optical disc manufactured in this embodiment is the same as that of fig. 3, that is, fig. 1, and not only the identification information of the optical disc, such as the media ID and version (version) information, but also information indicating the relationship between the reflectance of the unrecorded area of the user data area a of the optical disc and the reflectance in the recorded state is recorded in the barcode area C. Specifically, the optical disc manufactured according to this embodiment is an LH optical disc, and information for increasing the reflectance by recording is recorded in a predetermined area of the barcode area C. In addition, in the barcode region C, values of the reflectance in the unrecorded state and the reflectance in the recorded state of the user data region a may be recorded as information on the reflectance of the optical disk. A method of recording information in the barcode area C will be described later.

(method for manufacturing optical disk)

Fig. 8 shows a schematic cross-sectional view of an optical disc manufactured according to this embodiment. The optical disk 40 manufactured according to this example has a structure in which, as shown in fig. 8, an organic dye recording layer 44, a thermal diffusion layer 7, a UV resin layer 8, and a transparent substrate 9 are arranged in this order on a substrate 1. In addition, in this example, the above-described layers are formed on the user data area a, the control data area B, and the barcode area C of the optical disc. The method of manufacturing the optical disc of the present embodiment is described below. In which the substrate 1 was fabricated in the same manner as in example 3.

First, an organic dye recording layer 44 containing an organic dye represented by the above chemical formula (1) in a carbostyril compound similar to that of example 3 is formed on the substrate 1. Specifically, 0.5g ofThe organic pigment represented by the above chemical formula (1) was dissolved in 40g of octafluoropentanol (octafluoropentanol), subjected to ultrasonic dispersion treatment at a temperature of 40 ℃ for 30 minutes, and then filtered through a 0.2 μm filter paper. Subsequently, the filtrate was spin-coated (spincoat) on the substrate 1 at 1000rpm, and dried in an oven at 80 ℃ for 30 minutes to form the organic dye recording layer 44. The organic dye recording layer 44 had a film thickness of 150 nm. Next, Al as a thermal diffusion layer 7 was formed on the organic dye recording layer 44 by thermal spraying to a film thickness of 150nm₉₇Ru₂Cu₁。

Next, an ultraviolet curable resin was applied as a UV resin layer 8 on the thermal diffusion layer 7, and a transparent substrate 9 made of polycarbonate (poly-carbonate) having a thickness of 0.6mn was further placed thereon. Then, ultraviolet rays are irradiated through the transparent substrate 9 to cure the ultraviolet curing resin, thereby bonding the transparent substrate 9 to the UV resin layer 8. By the above-described manufacturing method, the organic dye recording type optical disc 40 shown in fig. 8 is obtained.

In the optical disk manufactured according to this example, the reflectance of the unrecorded portion was 16%, and the reflectance of the recorded portion, i.e., the recorded mark portion was 32%.

(method of Forming Bar code region C)

In the optical disk manufactured according to this embodiment, a barcode region C is formed in the same manner as in embodiment 3 except that the pattern of laser intensity adjustment is changed when the barcode-like mark group is formed in the barcode region C. A method of forming the barcode area C of the optical disc manufactured according to the present example is described below.

Also in this embodiment, as in embodiment 3, adjustment of the intensity of the laser light at the time of recording the barcode information of the reflectance pattern shown in fig. 6(a) is considered. Since the optical disk manufactured according to this embodiment is an LH disk, the intensity adjustment of the laser light is performed as shown in fig. 6(c), and barcode information is recorded. In addition, before the information is recorded in the barcode region C, the entire surface of the recording layer of the optical disc is in an unrecorded state. Then, the area irradiated with a high laser power (10mW) is changed to a recording state, and the reflectance of the area is changed, thereby recording information.

In the LH disk, as shown in fig. 6(c), a portion intended to have a high reflectance (a portion in a recorded state) is irradiated with laser light of an intensity to achieve recording (10mW in fig. 6(c)) so as to be in a recorded state, as in the region H in fig. 6(a), and a portion intended to have a low reflectance (a portion in an unrecorded state) such as in the region L in fig. 6(a) is irradiated with laser light of a weaker intensity (0.5 mW in fig. 6(c)) so as to be kept in an unrecorded state. By adjusting the laser intensity in this manner, similarly in the LH disc, the same bar-code-like mark group corresponding to the reflectance pattern as shown in fig. 6(a) is formed as in the HL disc.

As is clear from fig. 6, when the optical disc is an LH disc as in the present embodiment, the intensity adjustment pattern of the laser beam (fig. 6(c)) is made to be a pattern opposite to the intensity adjustment pattern of the laser beam (fig. 6(b)) of the HL disc (embodiment 3), whereby information of the same reflectance pattern can be formed (fig. 6 (a)). If the information in the barcode region of the information recorded by such a method is reproduced, the information can be reproduced with a value in the substantially same reflectance range regardless of the type of the organic dye type optical disc (HL disc or LH disc). Therefore, when reproducing the information in the barcode region C, it is not necessary to perform gain adjustment or the like depending on the type of the optical disc, and the information in the barcode region C can be reproduced quickly and with high reliability.

Example 5

(recording/reproducing apparatus)

Fig. 5 shows a recording and reproducing apparatus for recording and reproducing information on the optical discs manufactured according to embodiments 1 to 4. As shown in fig. 5, the recording and reproducing apparatus 100 of the present embodiment is mainly composed of a motor 12 for rotating the optical disk 50 manufactured according to embodiments 1 to 4, an optical head 13 for irradiating the optical disk 50 with laser light, an optical head 13 for adjusting the amplification factor of a reproduction signal, a servo circuit 15 for performing tracking control, a gain adjustment circuit 14 for determining the type of the optical disk 50 (HL disk or LH disk), an LH/HL determination circuit 16, and a reproduction signal processing circuit 17 for performing information reproduction based on the reproduction signal. In the recording and reproducing apparatus 100 shown in fig. 5, only the information reproducing portion will be described. The information recording unit in the recording and reproducing device 500 has the same configuration as that of a conventional optical disc recording and reproducing device, and is therefore omitted in fig. 5.

The reproduced signal processing circuit 17 mainly includes a data demodulator 18 and an address demodulator 19, as shown in fig. 5. The data demodulator 18 reproduces information from the bar code information, control data, and a reproduction signal of user data input from the optical head 13 through the gain adjustment circuit 14, and outputs a reproduction result to a reproduced information processing system (not shown). The address demodulator 19 reproduces information from a reproduction signal of address information input from the optical head 13 through the gain adjustment circuit 14, and outputs a reproduction result to the reproduced information processing system.

The optical head 13 includes a laser light source having a wavelength of 405nm and an objective lens having an aperture number of 0.65. When the laser beam is irradiated from the optical head 13 to the optical disc 50, the intensity of the laser beam is adjusted so that the intensity of the laser beam focused on the surface of the optical disc 50 is 0.5mW on the surface of the optical disc 50. In the present embodiment, as a rotation control method for performing recording and reproduction of information, a ZCLV method is adopted in which the rotation number of the optical disc 50 is changed for each area where recording and reproduction are performed.

In the recording and reproducing apparatus 100 shown in fig. 5, the steps of recording and reproducing information are as follows. First, after the optical disc 50 is mounted on the recording and reproducing apparatus 100, the motor 12 rotates the optical disc 50 at a predetermined number of revolutions. Next, the optical head 13 irradiates the bar code area C of the rotating optical disc 50 with laser light to reproduce information in the bar code area C. At this time, focus adjustment is performed so that the focal position of the laser light is held on the surface of the optical disc.

In this case, since the information in the barcode region C is formed by a barcode-like mark group having a sufficient length (about 1mm) in the radial direction, information can be easily reproduced even when the position control in the radial direction of the laser light is not strictly performed, that is, even when the tracking control is not strictly performed. In addition, if the information recorded in the barcode region C is repeatedly recorded within the range of one week, the reliability of information reproduction in the barcode region C is further improved. As described above with respect to the method of forming the barcode region C, the barcode region C of the optical disc 50 can be formed so that the ranges of the reflectances of the mark groups of the bar codes have the same value regardless of the type of the optical disc 50 (HL disc or LH disc), and therefore, in the information reproduction of the barcode region C, it is not necessary to perform gain adjustment or the like depending on the type of the optical disc 50, and the reproduction process can be performed quickly and with high reliability.

Next, information indicating whether the optical disc 50 is an HL disc or an LH disc, that is, information on the reflectance of the optical disc 50, out of the reproduction signal detected from the barcode region C, is input to the LH/HL determination circuit 16 via the gain adjustment circuit 14.

The LH/HL determination circuit 16 determines whether the optical disc 50 is an HL disc or an LH disc based on the information about the reflectivity of the optical disc 50 that has been input. Then, the determination result is sent to the gain adjustment circuit 14, and the gain adjustment circuit 14 determines an appropriate amplification factor of the reproduction signal input from the optical head 13 based on the determination result.

Then, the optical head 13 is moved to the control data area B to perform tracking control and reproduce control data. Information on the physical format (recording polarity, reflectance, etc.) and recording conditions (recording linear velocity, recording power, recording pulse width, etc.) of the disc is read from the pit rows recorded in the control data area B in advance, and stored in a recording control unit (not shown) in the recording/reproducing apparatus.

Subsequently, the optical head 13 is moved to a predetermined address area of the user data area a, and data recording is performed based on the information of the control data area B that has been reproduced.

The procedure for reproducing the information recorded in the user data area a is as follows. The optical head 13 is moved to a predetermined address area of the user data area a, and is irradiated with laser light, and a reflected light signal (reproduction signal) from the optical disc 50 is detected by the optical head 13. The reproduced signal detected by the optical head 13 is amplified by a gain adjusting circuit 14 at an appropriate amplification factor and sent to a data demodulator 18. The data demodulator 18 reproduces the user information from the amplified reproduction signal and sends the user information to the reproduction information control system.

In the above-described recording and reproducing apparatus, before reproducing the information in the control data area B and the user data area a, an appropriate amplification factor of the reproduction signal can be determined based on the information on the type of the optical disk (HL disk or LH disk) recorded in the barcode area C. Therefore, when information in the control data area B and the user data area a is reproduced, a reproduction signal having an appropriate amplitude is obtained by adjusting the gain without depending on the type of the optical disc. Thus, the information recorded on the optical disc can be reproduced further quickly and with higher reliability. In addition, even when detecting a servo signal for tracking an optical disc, the signal can be detected at an appropriate amplitude regardless of the type of the optical disc, and thus information can be reproduced with higher reliability.

In the above-described recording and reproducing apparatus, the optical disks manufactured according to embodiments 1 to 4 are mounted, and information is recorded and reproduced, and in this case, regardless of whether the phase change recording type and organic dye type optical disks are HL optical disks or LH optical disks, user information can be reproduced with high reliability without adjusting the gain.

In embodiments 1and 2, as shown in fig. 3, when forming the mark group of the bar code in the barcode region C of the optical disc, laser light of a weak intensity (150mW) is irradiated to the region held in the amorphous state, but the present invention is not limited thereto, and laser light may not be irradiated to the region held in the amorphous state.

In the above-described 1 st to 4 th embodiments, information is recorded in the barcode region C in fig. 1 within one circumference of the optical disc, but the present invention is not limited to this, and a barcode-like mark group may be formed in a part of the barcode region C. Further, 1 set of information (information on the identification information of the optical disk, the reflectance of the optical disk, and the like) to be recorded in the barcode region C may be repeatedly recorded. By repeatedly recording information in the barcode region C, the reliability of the information in the barcode region C is further improved.

Industrial applicability of the invention

According to the optical disc of the present invention, since information on the reflectivity of the optical disc is recorded in the barcode region, it is easy to obtain the information without performing strict tracking control and gain adjustment. As a result, the optimum gain adjustment of the reproduced signal can be performed quickly. Therefore, the optical disc of the present invention can be an optical disc in which information of the control data region and the user data region and a tracking servo signal can be reproduced quickly and with high reliability, regardless of the type of the optical disc (HL disc or LH disc).

According to the recording/reproducing apparatus and the reproducing method of the present invention, information on the reflectance of the optical disc recorded in the barcode region of the optical disc is detected without performing strict tracking control and gain adjustment, and the type of the optical disc (HL disc or LH disc) is determined based on the information, thereby determining an appropriate amplification factor of the reproduced signal. Accordingly, the recording/reproducing apparatus and the reproducing method according to the present invention are suitable for reproducing information in the control data area and the user data area and servo signals for tracking, quickly and with high reliability, regardless of the type of the optical disk (HL disk or LH disk).

In addition, according to the method of manufacturing an optical disc of the present invention, when the bar code-shaped mark is formed by the recording layer formed of the phase change material, the patterns of the intensity adjustment of the light beam are reversed as shown in fig. 3 according to the type of the optical disc, and thus, the information of the same reflectance pattern can be formed in both the HL disc and the LH disc. When the barcode-like mark is formed on the recording layer made of the organic pigment material, the patterns of the intensity adjustment of the light beam are reversed as shown in fig. 6 depending on the type of the optical disc, and thus, the information of the same reflectance pattern can be formed in both the HL disc and the LH disc. As a result, in the optical disc manufactured by the manufacturing method of the present invention, when reproducing the information of the barcode region, the information can be reproduced with the same value of the reflectance range regardless of the type of the optical disc (HL disc or LH disc). Accordingly, the manufacturing method of the present invention is an optimum manufacturing method for manufacturing an optical disc that can reproduce information in a barcode region quickly and with high reliability without performing gain adjustment or the like depending on the type of the optical disc.

Claims (5)

1. An optical disc recording/reproducing apparatus for recording information on a reflectivity of an optical disc in a region where a plurality of marks extending in a radial direction of the optical disc are arranged in a track direction, the apparatus comprising:

an optical head that irradiates the optical disc with a light beam;

a signal processing circuit for reproducing information based on the reproduction signal detected by the optical head;

a gain adjustment circuit that adjusts an amplification factor of the reproduction signal;

a judgment circuit for identifying the type of the optical disc based on information relating to a change in the reflectivity of the optical disc, the information relating to the change in the reflectivity being information in which the reflectivity changes from a low value to a high value or in which the reflectivity changes from a high value to a low value;

the gain adjusting circuit adjusts the amplification factor of the reproduction signal according to the judgment result of the judging circuit;

the information on the reflectivity of the optical disc is information indicating a relationship between the reflectivity in an unrecorded state and the reflectivity in a recorded state in a user information area in the optical disc.

2. A method of reproducing an optical disc having information on the reflectivity of the optical disc recorded in a region where a plurality of marks extending in the radial direction of the optical disc are arranged in the track direction, the method comprising the steps of:

irradiating the region with a light beam;

reproducing information relating to the reflectivity of the optical disc based on the reflected light from the area;

identifying the type of the optical disc according to the information related to the reflectivity change of the optical disc;

determining an amplification factor of a reproduction signal based on the reproduced information on the reflectance of the optical disc;

reproducing information recorded in an area other than the area according to the determined amplification factor of the reproduction signal;

the information on the reflectance of the optical disc is information indicating a relationship between the reflectance in an unrecorded state and the reflectance in a recorded state in the user information area in the optical disc, and the information on the change in the reflectance is information indicating a change in the reflectance from a low value to a high value or a change in the reflectance from a high value to a low value.

3. A method for manufacturing an optical disc, characterized in that the manufacturing method comprises the steps of:

in the optical disk, a recording film is provided;

adjusting the light intensity according to the change information of the reflectivity in the unrecorded state and the reflectivity in the recorded state, and recording the mark group;

irradiating a recording film in a predetermined area of the optical disc with a light beam to form a mark group in which a plurality of marks extending in a radial direction are arranged in a track direction;

the mark group is formed as information related to the reflectivity of the optical disc;

the information on the reflectivity of the optical disc is information indicating a relationship between the reflectivity in an unrecorded state and the reflectivity in a recorded state of the user information area of the optical disc.

4. The manufacturing method according to claim 3, characterized in that: the recording film is formed of a phase-change material, and the step of forming the mark group includes adjusting an intensity of the light beam based on a relationship between a reflectance in an unrecorded state and a reflectance in a recorded state of the user information area, thereby recording information indicating the relationship between the reflectance in the unrecorded state and the reflectance in the recorded state of the user information area as the mark group in the recording film.

5. The manufacturing method according to claim 3, characterized in that: the recording film contains an organic dye, and the step of forming the mark group includes adjusting the intensity of the light beam based on a relationship between a reflectance in an unrecorded state and a reflectance in a recorded state of the user information area, thereby recording information indicating the relationship between the reflectance in the unrecorded state and the reflectance in the recorded state of the user information area as the mark group in the recording film.