JP2003344271A - Method and apparatus for measuring reflectance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a cost required for selecting a recording material and a time for measuring reflectance. <P>SOLUTION: A recording layer 4 of an optical recording medium includes films of materials of N types (N is a positive integer equal to or greater than 2). When a laser beam for recording is irradiated to the recording layer 4, atomic arrangement thereof changes such that reflectance with respect to the laser beam for reproducing with a predetermined wavelength changes. In a method for measuring the reflectance of the recording layer 4, the laser beam for reproducing is irradiated onto the recording layer 4 while a heater applies heat to the recording layer 4 covering a base material 2, and reflectance of the recording layer 4 for a predetermined temperature is measured. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflectance measuring method for measuring the reflectance of a recording film for an optical recording medium, the reflectance of which changes with respect to a reproducing laser beam having a predetermined wavelength by irradiation with a recording laser beam. The present invention relates to a reflectance measuring device.

[0002]

2. Description of the Related Art Today, various optical recording media have come into wide use due to the fact that a large amount of recording data can be recorded. In this case, there are read-only type, write-once type and rewritable type optical recording media of this kind, and in order to maintain compatibility between them, the entire size (diameter and thickness, etc.) and recording are possible. The capacity, mechanical characteristics, and optical characteristics are defined by standards. Therefore, when developing a write-once (or rewritable) type optical recording medium capable of writing record data while maintaining compatibility with a read-only type optical recording medium, in particular, to maintain compatibility of optical characteristics. In addition, it is important to select the material (hereinafter, also referred to as "recording material") itself used for each layer that can be recorded, particularly the recording film of the recording layer. In this case, in this type of optical recording medium, the presence or absence of pits (recording marks) is determined based on the difference in reflectance with respect to the reproducing laser beam with which the recording film is irradiated with a predetermined wavelength and a predetermined irradiation power during reproduction. . Therefore, the recording material needs to have a certain or more difference in reflectance with respect to the reproducing laser beam before and after irradiation with the recording laser beam with which the recording film is irradiated with a predetermined wavelength and a predetermined irradiation power during recording. Therefore, when selecting the recording materials, we made a number of prototypes (optical recording media for material selection) in which the recording layer was formed using various recording materials, and actually used these recording laser beams for recording. By irradiating with and forming a recording mark,
The suitability as a recording material is evaluated by measuring the reflectance with respect to the reproducing laser beam before and after the irradiation of the recording laser beam.

In this case, when recording data is recorded on an optical recording medium as a product, it depends on recording conditions such as performance of a recording device (wavelength of recording laser beam and numerical aperture of pickup) and setting regarding recording method. hand,
The irradiation power of the recording laser beam and the rotation speed of the optical recording medium are various. Therefore, when evaluating a recording material using a prototype, the irradiation amount of the recording laser beam on the recording film should be increased in consideration of the fact that the irradiation amount of the recording laser beam on the recording film per unit time differs depending on the recording conditions. The recording mark is recorded by changing the stage. Next, the reflectance of the unrecorded portion with respect to the reproducing laser beam and the reflectance of the recording portion with different irradiation amount of the recording laser beam (recording portion of the recording mark) with respect to the reproducing laser beam were measured for each prototype. To do. After that, the difference between the reflectance of the unrecorded portion and the reflectance of each recorded portion is calculated to determine whether the difference between the reflectances is within the range suitable for reading the recorded data. As a result, the suitability of the recording material used for the prototype as the recording material for the recording film is determined.

[0004]

However, the conventional recording material selection methods have the following problems. That is,
In the conventional selection method, a large number of prototypes in which a recording layer is formed using various recording materials are prepared, and a recording laser beam is irradiated to these prototypes to actually record a recording mark. The reflectance of the reproducing laser beam before and after the irradiation of the recording laser beam is measured. In this case, in the conventional selection method, since the recording mark is actually recorded by irradiation with the recording laser beam, the prototype including the groove, the land, and the cover layer is produced like the optical recording medium as the product. Therefore, various devices for forming these may be required. Therefore, there is a problem that the development cost of the optical recording medium is soaring due to the cost required to manufacture a large number of prototypes. In addition, in order to accurately measure the reflectance, it is necessary to form a recordable area in which the reflectance can be measured by a measuring device.
Further, in order to form a recording mark on this prototype by linearly irradiating it with a recording laser beam, it takes a long time to irradiate the recording laser beam, which further increases the development cost. Further, in the conventional selection method, the recording mark is recorded by changing the irradiation amount of the recording laser beam in multiple stages in consideration of the recording condition of the recording data on the optical recording medium as a product. For this reason, it takes a long time to measure the reflectance for each irradiation amount, which causes a problem that the development cost of the optical recording medium rises and the development time is delayed due to the extra time required.

Further, in the conventional method of selecting the recording material,
Since the pickup that emits the recording laser beam has a limit on the emission power, for example, it records up to a temperature that is considered to be realized in the future, greatly exceeding the actual use state assumed from the current state at the time of development. The layers are difficult to heat. For this reason, the original characteristics of the recording layer cannot be fully inspected, and it is difficult to accurately determine whether or not the recording material being selected is suitable as a material for the recording film. In addition, in the conventional method of selecting a recording material that forms a recording mark by irradiating the recording laser beam, the heat generation efficiency of the recording film is considered in consideration of the effect of the absorption characteristics of the recording material itself on the wavelength of the recording laser beam. However, there is a problem that the selection of the recording material is complicated. Furthermore, in the conventional method of selecting the recording material, the structure (reflection layer, protective layer, groove, land, etc.) as an optical recording medium for irradiating the recording laser beam is indispensable. There is also a problem that it is difficult to grasp the change in the reflectance of the recording film itself due to the influence of the above.

The present invention has been made in view of the above problems, and in order to reduce the development cost of an optical recording medium and the development period, the reflectance required while reducing the cost required for selecting a recording material. A main object of the present invention is to provide a reflectance measuring method and a reflectance measuring apparatus that can shorten the measuring time and grasp the optical characteristics of a single recording film.

[0007]

In order to achieve the above-mentioned object, a reflectance measuring method according to the present invention is a method of forming a film containing N kinds of materials (N is a natural number of 2 or more) and irradiating a recording laser beam. A reflectance measuring method for measuring the reflectance of a recording film for an optical recording medium in which the reflectance for a reproducing laser beam having a predetermined wavelength changes due to a change in the atomic arrangement caused by: While applying heat from a heating element to the formed recording film, the reproducing laser beam is emitted toward the recording film and the reflectance of the recording film at each predetermined temperature is measured. In the present invention, the recording laser beam is a laser beam capable of changing the atomic arrangement of the recording film, and is not particularly limited as long as the atomic arrangement can be changed. Further, the reproducing laser beam also refers to a laser beam capable of discriminating a change in reflectance before and after a change in the atomic arrangement of the recording film, and is not particularly limited as long as the change can be discriminated.

In this case, it is preferable to measure the reflectance every predetermined time while heating the recording film at a constant temperature rising rate.

Further, when the recording film is heated, it is preferable to measure the reflectance by heating the recording film to an optical recording medium having the recording film at a temperature higher than a heating temperature by the recording laser beam.

Further, it is preferable that the recording film is formed on a glass plate as the substrate, and the reflectance of the formed recording film is measured.

Further, it is preferable to measure the reflectance by using a laminated body in which metal thin films as the material are laminated as the recording film.

Further, the reflectance measuring device according to the present invention is
An optical recording medium that is formed by including N kinds of materials (N is a natural number of 2 or more) and changes the atomic arrangement by irradiation of a recording laser beam, thereby changing the reflectance with respect to a reproducing laser beam of a predetermined wavelength. A reflectance measuring device for measuring the reflectance of a recording film for use, comprising: heating means for heating a sample having the recording film formed on a base material by heating a heating element; A laser emitting section for emitting the reproducing laser beam to the sample, a laser receiving section for receiving the reproducing laser beam reflected by the sample, and a reception of the reproducing laser beam received by the laser receiving section. The measuring unit for measuring the reflectance of the sample based on the level, the heating unit, the laser emitting unit, the laser receiving unit and the measuring unit are controlled. And a control unit that controls the heating unit to heat the sample, and causes the laser emission unit to emit the reproduction laser beam to the sample to the measurement unit. The reflectance for each predetermined temperature of the sample is sequentially measured based on the light reception level of the reproduction laser beam reflected by the sample and received by the laser light receiving unit.

In this case, it is preferable that the control section causes the heating means to heat the sample at a constant temperature rising rate and causes the measuring section to measure the reflectance at predetermined intervals.

Further, the control section causes the heating means to heat the sample to a temperature equal to or higher than a heating temperature by the recording laser beam at the time of recording recording data on the optical recording medium having the recording film of the sample. With
It is preferable that the measuring unit measures the reflectance.

Further, it is preferable that the laser emitting section is capable of selectively emitting the reproducing laser beam in an arbitrary wavelength region to the sample.

Further, there is provided a display section for displaying predetermined information on the recording film, and a storage section for storing discrimination data for discriminating the suitability of the recording film as a recording film for an optical recording medium. The controller determines the suitability of the material used in the sample as the recording film based on the reflectance measured at each of the predetermined temperatures and the determination data stored in the storage. It is preferable to display the determination result on the display unit.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a reflectance measuring method and a reflectance measuring apparatus according to the present invention will be described below with reference to the accompanying drawings.

First, the structure of the optical recording medium 1 will be described with reference to the drawings.

The optical recording medium 1 shown in FIG. 1 is an example of an optical recording medium manufactured using a recording material selected based on the reflectance measured by the reflectance measuring method according to the present invention. This optical recording medium 1 is a so-called single-sided single-layer write-once type optical recording medium, and comprises a reflection layer 3, a recording layer 4, a protective layer 5 and a reflection layer 3 on a flat plate-shaped (disc-shaped as an example) substrate 2. The cover layer 6 is laminated. The base material 2 is formed by injection molding with a resin material such as polycarbonate, and fine irregularities such as spiral grooves (guide grooves) and lands are formed on the surface thereof. The reflective layer 3 is a layer for reflecting the recording laser beam and the reproducing laser beam (hereinafter, also referred to as “laser beam” when not distinguished) emitted in the direction of arrow X, and is made of Au, Ag, Al.
It is formed into a thin film of a metal such as or an alloy thereof.

The recording layer 4 corresponds to the recording film of the present invention, and as shown in FIGS. 1 and 2 (a), between the first protective film 5a and the second protective film 5b forming the protective layer 5. The first sub-recording film 4a and the second sub-recording film 4a are provided so as to be sandwiched in order from the laser beam incident direction (direction of arrow X).
Two thin films of the sub recording film 4b are laminated on the second protective film 5b. As shown in FIG. 2B, the recording layer 4 is mixed by being melted / diffused by irradiation with a recording laser beam, that is, the atomic arrangement is changed to become the recording portion M, and thus the optical constant is obtained. Changes (optical pit formation) to record the record data. In this case, the first sub-recording film 4a is made of a highly reflective metal (for example, Al, Cu,
Ag, Au, etc.), and the second sub-recording film 4b is
Reactive metal or semi-metal having a characteristic that it is easily melted, diffused and mixed with the metal adopted as the sub-recording film 4a (for example, Sn, Te, Sb, Ge, Si, C).
Is formed by. On the other hand, the protective layer 5 is a layer for preventing the first sub-recording film 4a and the second sub-recording film 4b from being oxidized or deformed during irradiation of the recording laser beam,
As an example, it is formed of a dielectric material such as ZnS + SiO ₂ . The cover layer 6 is a layer provided for the purpose of preventing damage to each layer on the base material 2, and is made of a light-transmissive resin or the like.

In this case, regarding the recording layer 4, the kind of recording material used for the first sub-recording film 4a and the second sub-recording film 4b, the first sub-recording film 4a and the second sub-recording film 4b, respectively.
The reflectance with respect to the reproducing laser beam before and after the irradiation of the recording laser beam differs depending on the respective thicknesses (that is, the ratio of each recording material in the recording layer 4). Further, for example, when the first sub recording film 4a is formed of Al and the second sub recording film 4b is formed of Si, and when the first sub recording film 4a is formed of Si and the second sub recording film 4b is formed of Al. As a matter of course, the reflectance of the recording laser beam before irradiation of the recording laser beam differs from that of the recording laser beam when formed (the same ratio of the recording materials used for both metal layers). The reflectance for the reproducing laser beam after irradiation with is also different. Therefore, when selecting the recording material to be used for the first sub-recording film 4a and the second sub-recording film 4b, the combination of recording materials used for both the sub-recording films 4a and 4b, the ratio (thickness of each sub-recording film), Also, it is necessary to change the film forming sequence variously and measure the reflectance with respect to the reproducing laser beam. Therefore, a large number of prototypes (samples) for material selection have to be prepared, and therefore, the formation of the cover layer 6 and the formation of grooves and lands on the base material 2 which are unnecessary for the selection of the recording material itself are performed. By making it unnecessary,
It is possible to suppress the development cost of the optical recording medium 1 by the amount corresponding to the cost reduction of sample preparation.

Next, the reflectance measuring device 31 for measuring the reflectance according to the reflectance measuring method according to the present invention, and the sample 11 as the measurement target of the reflectance measuring device 31 will be described with reference to the drawings.

The reflectance measuring device 31 is a device for measuring the reflectance with respect to the reproducing laser beam when selecting the recording material, and as shown in FIG.
2, laser emitting section 33, laser receiving section 34, measuring section 35, display section 36, control section 37, RAM 38 and RO
Equipped with M39. The optical microscope 32 includes a heating stage 41 and an optical system 42, and the laser emitting section 33 and the laser receiving section 34 can be mounted on the optical system 42. The heating stage 41 includes a heater 41a, which corresponds to the heating means of the present invention and corresponds to the heating element of the present invention, and a power feeding section 41b which supplies power to the heater 41a under the control of the control section 37, and selects a recording material. The sample 11 for use is placed. The optical system 42 extracts a laser beam in an arbitrary wavelength region from the incident reproducing laser beam (hereinafter, also referred to as “laser beam”) L and outputs it as an emission laser La.
a, which emits an emission laser La toward the sample 11 and which is reflected by the sample 11 (hereinafter,
(Also referred to as “reflection laser Lb”)
I will guide you to. In this case, the spectroscope 42a is the optical recording medium 1
The emitted laser La corresponding to the wavelength region of the reproducing laser beam used when reproducing the recorded data is extracted.

The laser emitting section 33 emits a laser beam L to the optical system 42 of the optical microscope 32 under the control of the control section 37. The laser light receiving unit 34 receives the reflected laser Lb reflected by the sample 11 and guided by the optical system 42, and outputs a level signal corresponding to the received light level to the measuring unit 35. The measuring unit 35 obtains the value of the total reflectance with respect to the laser beam (exiting laser La) used in the measurement in advance, and obtains the obtained value and the level signal output by the laser light receiving unit 34. Based on this, the reflectance of the sample 11 is calculated (measured) and output to the controller 37. The display unit 36 displays the progress of measurement of the reflectance, the measurement result of the measurement unit 35, and the sub recording films 4a and 4a.
A determination result indicating whether or not the material used for b is suitable as a recording material for an optical recording medium is displayed. The control unit 37 controls the emission of the laser beam L to the laser emission unit 33, the measurement control of the measurement unit 35, and the display unit 3.
Display control for 6 and power supply control for the power supply section 41b are performed, and the suitability of the recording material used for the recording layer 4 as the recording material for the optical recording medium 1 is determined. The RAM 38 temporarily stores the calculation result of the control unit 37. The ROM 39 corresponds to the storage section in the present invention, and the recording material used for the sample 11 is the optical recording medium 1.
Judgment data (permissible value regarding reflectance) for judging whether or not it has an aptitude as a recording material for recording, an operation program of the control unit 37, and the like are stored.

On the other hand, the sample 11 is the optical recording medium 1 described above.
4 is a sample for reflectance measurement having only the recording layer 4 of the layer structure, and the recording layer 4 is laminated on the base material 2A as shown in FIG. The layer structure in the recording layer 4 is
It is the same as the recording layer 4 in the optical recording medium 1, and when selecting the recording material, the type of recording material used for the first sub-recording film 4a and the second sub-recording film 4b and both sub-recording films 4a and 4b.
Various kinds of samples 11a, 1 with various thicknesses
1b, 11c ... (Hereinafter, when no distinction is made, "Sample 1
1 "). In this case, it is not necessary to actually record a recording mark (irradiate a recording laser beam) in the reflectance measurement using the sample 11a. Therefore, in this sample 11, a flat glass plate having no groove and land is present. The base material is adopted as the base material 2A. Further, it is necessary to measure the change in the characteristics of the recording layer 4 alone at the time of measuring the reflectance, and since the recording layer 4 is not likely to be damaged, the cover layer 6 is not necessary on the recording layer 4. Therefore, compared with the conventional material selection method in which a prototype equivalent to an optical recording medium as a product is manufactured, the manufacturing cost of the base material 2A and the reflective layer 3 and the protective layer 5 are increased.
The cost required for selecting the recording material (that is, the development cost of the optical recording medium 1) is reduced by the film forming cost of the cover layer 6 and the like.

In this case, when the reflectance of the recording layer 4 is measured in the atmosphere, the metal material used for the sub recording films 4a and 4b may be oxidized or deformed. It may be a hindrance in obtaining the characteristics of the intrinsic reflectance change of the. Therefore, when the measurement is performed in the atmosphere, by forming the first protective film 5a and the second protective film 5b above and below the recording layer 4,
It is preferable to measure the change in the optical characteristics of the protective layers 5a and 5b. Further, when measuring the change in the optical characteristics including the reflective layer 3, the reflective layer 3 may be formed on the base material 2A.

Next, a method of measuring the reflectance by the reflectance measuring device 31 will be described with reference to the drawings.

First, the sample 11 to be measured is placed on the heating stage 41. Next, the control unit 37 causes the power feeding unit 41b.
Power is supplied to the heater 41a. At this time,
The power supply unit 41b supplies power so that the heater 41a generates heat at a constant temperature rising rate. As a result, the heater 41a generates heat, and the sample 11 on the heating stage 41 is heated at a constant temperature rising rate. Next, the control unit 37 emits the laser beam L to the laser emitting unit 33 when a predetermined time has elapsed from the start of heating the sample 11 by the heater 41a (as an example, when the sample 11 is heated to 100 ° C.). Let In this case, the control unit 37 calculates how many times the sample 11 is heated based on the rate of temperature rise of the sample 11 by the heater 41a and the elapsed time from the start of heating. It should be noted that it is also possible to perform pre-calculation based on the rate of temperature rise and store the elapsed time and the temperature of the sample 11 in association with each other in the ROM 39 or the like.

On the other hand, in the optical system 42 which has received the laser beam L emitted by the laser emitting section 33, the spectroscope 42a extracts the laser beam in a specific wavelength region from the laser beam L and outputs it as a sample laser La. 1
Emit toward 1. At this time, the laser receiving unit 34 receives the reflected laser Lb reflected by the sample 11 and outputs a level signal corresponding to the received light level to the measuring unit 35. In response to this, the measuring unit 35 causes the emission laser La to
The reflectance of the sample 11 is calculated based on the laser power and the level signal output by the laser light receiving unit 34 and output to the control unit 37. At this time, the control unit 37
The calculation result of the measurement unit 35 (result measurement result of the reflectance of the sample 11) is stored in the RAM 38 as the reflectance at the start of measurement (100 ° C. as an example).

Subsequently, the control unit 37 causes the laser emitting unit 33 to emit the laser beam L at predetermined intervals and causes the measuring unit 35 to measure the reflectance. At this time, when the sample 11 (recording film) is heated, the temperature of the substrate surface in a state of being heated by the irradiation of the recording laser beam when recording the record data on the optical recording medium including the recording layer 4 of the sample 11. The reflectance is measured by heating to a temperature (for example, 400 ° C.) or higher (for example, 500 ° C.). Thereby, the reflectance of the sample 11 at each predetermined temperature is measured, and the measurement result is stored in the RAM 38. Further, when the reflectance measurement of the sample 11 is completed, the control unit 37 graphs the change of the reflectance for each temperature of the sample 11 to be measured based on the measurement result stored in the RAM 38. The measurement result display (see FIGS. 5 and 6) is displayed on the display unit 36. After that, another sample 11 in which the type of recording material used for the first sub-recording film 4a and the second sub-recording film 4b and the thicknesses of the two sub-recording films 4a and 4b are different
Also for b, 11c, ..., While the heating by the heater 41a is performed, the reflectance is measured at a predetermined temperature by the measuring unit 35, and the reflectance of each sample 11 at each predetermined temperature is measured. It is stored in the RAM 38, and the measurement result display for each sample 11 is displayed on the display unit 36 each time. At this time, as the measurement result display, a reaction temperature (temperature having the largest slope (that is, a differential absolute value)) determination result, a temperature transition (monitor) result, a reflectance temperature difference determination result, an appropriate / inappropriate display, and the like are displayed. It is displayed on the display unit 36.

Then, the control unit 37 uses the recording material used for each of the samples 11, 11 ... As an optical source based on the measurement result stored in the RAM 38 and the discrimination data stored in the ROM 39. It is determined whether or not the recording layer 4 for the recording medium 1 is suitable. In this case, for example, S
In the sample 11 in which the first sub-recording film 4a was formed by using n and the second sub-recording film 4b was formed by using Al, as shown by the solid line A in FIG. In a certain temperature range, it has a characteristic that the change in reflectance with temperature rise is small. Therefore, when the optical recording medium 1 is manufactured by using this recording material, the difference in the reflectance of the reproducing laser beam before and after the irradiation of the recording laser beam (that is, the unrecorded portion and the recording portion of the recording mark) It is difficult to read the recording mark because of the small difference in reflectance from the recording mark. Therefore, the control unit 37 controls the sample 1
It is determined that the recording material used in No. 1 (Sample 11 having the characteristic indicated by the solid line A) does not have the suitability to form the recording layer 4, and the fact (the determination result in the present invention) is displayed on the display unit 36. Display it.

The first sub-recording film 4 is made of, for example, Te.
The sample 11 in which the second sub-recording film 4b is formed by using a while forming a has a characteristic that the change in reflectance with temperature rise does not change monotonically, as indicated by the chain line B in FIG. ing. Therefore, when the optical recording medium 1 is manufactured by using this recording material, the reflectance of the recording mark forming portion varies depending on the recording condition of the recording data, which makes it difficult to read the recording data normally. Becomes Therefore, the control unit 37 determines that the recording material used for this sample 11 (sample 11 having the characteristic indicated by the alternate long and short dash line B) is not suitable for forming the recording layer 4, and displays that fact. It is displayed on the section 36. Similarly, for example, Al is used to form the first sub-recording film 4a and G
In the sample 11 in which the second sub-recording film 4b is formed by using e,
As indicated by a broken line C in the figure, the change in reflectance with temperature rise does not change monotonically. Therefore, the control unit 37
It is determined that the recording material used for this sample 11 is not suitable for forming the recording layer 4, and a message to that effect is displayed.
6 to display.

On the other hand, the first sub-recording film 4 is made of, for example, Al.
In Sample 11 in which the second sub-recording film 4b was formed using Si while forming a, the change in reflectance with temperature rise was extremely large, as indicated by the solid line D in FIG. Therefore,
When the optical recording medium 1 is manufactured by using this recording material, the difference in the reflectance of the reproducing laser beam before and after the irradiation of the recording laser beam (that is, the reflection between the unrecorded portion and the recording portion of the recording mark). Therefore, the recording mark can be reliably read. Also,
This sample 11 has a small change in reflectance until reaching a predetermined temperature (in this case, about 300 ° C.), and when the reflectance exceeds a predetermined value, the reflectance rapidly changes and after the reflectance changes. It has a characteristic that the reflectance does not change significantly even if the temperature is further increased. Therefore, when the optical recording medium 1 is manufactured by using this recording material, an unintended change in reflectance (formation of a recording mark) of the recording layer 4 in a normal temperature range (a state where recording of recording data is not performed) occurs. It is possible to provide a stable recording medium which is avoided and whose reflectance changes only when irradiated with a recording laser beam. Therefore, the control unit 37 determines that the recording material used for this sample 11 (sample 11 having the characteristic indicated by the solid line D) has the optimum suitability for forming the recording layer 4, This is displayed on the display unit 36. In this case, the control unit 37, as an example, the reflectance when the temperature of the sample 11 is 80 ° C. (first temperature in the present invention) and 500 ° C.
At this time (the second temperature in the present invention), the difference in reflectance is 1
When it is 0% or more, it is determined that the recording material used for the sample 11 is suitable as a recording material for the optical recording medium 1. The temperature (80 ° C.) is lower than the heating temperature (for example, 400 ° C.) by the recording laser beam when recording the recording data on the optical recording medium including the recording layer 4 of the sample 11.
The temperature (500 ° C.) is specified to be higher than the heating temperature (for example, 400 ° C.) by the recording laser beam.

The first sub-recording film 4 is made of Cu, for example.
In the sample 11 in which the second sub-recording film 4b was formed using Ge while forming a, as indicated by a chain line E in FIG.
The reflectance does not change significantly until the temperature reaches a predetermined temperature (in this case, about 200 ° C), and when the reflectance exceeds the predetermined value, the reflectance changes abruptly, and the temperature changes after the large change in the reflectance. It has the characteristic that its reflectance does not change significantly even when it is raised. Therefore, when the optical recording medium 1 is manufactured by using this recording material, the reflectance changes only when the recording laser beam is irradiated, like the sample 11 having the characteristics shown by the solid line D. It is possible to provide a stable recording medium. However, this sample 1
In No. 1, since the difference in reflectance with respect to the reproducing laser beam before and after the temperature rise (that is, before and after irradiation with the recording laser beam) is smaller than that of the sample 11 shown by the solid line D, it becomes slightly difficult to read the recording mark. There is a risk. Further, since the reflectance changes at a temperature lower than that of the sample 11 indicated by the solid line D, the reflectance of the recording layer 4 may change unintentionally. Therefore, the control unit 37 determines that the recording material used for the sample 11 (sample 11 having the characteristic indicated by the alternate long and short dash line E) does not have the optimum suitability for forming the recording layer 4, This is displayed on the display unit 36. In this case, when the reflectance measuring method according to the present invention is performed with the protective layer 5 (the first protective film 5a and the second protective film 5b) formed so as to sandwich the recording layer 4, the sample is heated to a high temperature. At that time, the dielectric material of the protective layer 5 and the metal material of the recording layer 4 may react with each other. Therefore, for the same recording layer 4, it is preferable to separately evaluate a sample without the protective layer 5 and a sample with the protective layer. Further, it is more preferable to form the protective layer with a material that does not react with the metal material used for the recording layer 4 during heating. In this case, the essence of the recording layer 4 can be obtained only by preparing a sample having the protective layer. It is possible to measure a change in the optical characteristic of the object.

Further, in the sample 11 in which the first sub-recording film 4a is formed using Ag and the second sub-recording film 4b is formed using Ge, for example, as shown by the broken line F in FIG. The reflectance does not change significantly until it reaches (about 400 ° C. in this case), and when the reflectance exceeds a predetermined value, the reflectance changes abruptly, and even if the temperature is raised after the reflectance greatly changes. , Its reflectance does not change significantly. Therefore, when the optical recording medium 1 is manufactured by using this recording material, the solid line D and the chain line E
In the same manner as the sample 11 having the characteristics described in (1), it is possible to configure a recording medium whose reflectance changes only when irradiated with a recording laser beam. However, this sample 1
1 has a relatively small difference in reflectance with respect to the reproducing laser beam before and after the temperature rise (that is, before and after irradiation with the recording laser beam), similarly to the sample 11 having the characteristic indicated by the one-dot chain line E, There is a possibility that reading the recording mark will be slightly difficult. Further, since the reflectance changes at a temperature higher than that of the sample 11 indicated by the solid line D, the optical recording medium 1 manufactured by using this recording material has a large power for the recording laser beam when recording a recording mark. Is required, or the recording speed (the rotation speed of the optical recording medium 1) must be reduced for recording. Therefore, the control unit 37 determines that the recording material used for this sample 11 (sample 11 having the characteristic indicated by the broken line F) does not have the optimum suitability for forming the recording layer 4, and A message is displayed on the display unit 36.

As described above, according to the reflectance measuring apparatus 31, the sample 11 having the recording layer 4 formed on the base material 2A is heated by the heater 41a, and is emitted toward the sample 11 by the emission laser La (reproducing laser). Beam) and emits the sample 11
By measuring the reflectance for each predetermined temperature of
Unlike the conventional reflectance measuring method in which a recording laser beam is irradiated onto a prototype to actually record a recording mark, the groove and land necessary to irradiate the recording laser beam onto the base material 2A As a result, the formation of the reflection layer 3, the protective layer 5, the cover layer 6, and the like becomes unnecessary, and as a result, the manufacturing cost of the reflectance measurement sample can be sufficiently reduced. Therefore, the optical recording medium 1
The development cost can be reduced. Sample 11
Since the state in which the irradiation power of the recording laser beam is changed in multiple stages can be reliably and easily reproduced in a short time by measuring the reflectance for each predetermined temperature of It is possible to determine accurately and in a short time whether or not the recording material used is suitable for forming the recording layer 4 for the optical recording medium 1. As a result, the development cost of the optical recording medium 1 can be sufficiently reduced.

Further, according to this reflectance measuring device 31, the controller 37 heats the sample 11 at a constant temperature rising rate by the heater 41a, and the reflectance of the sample 11 is measured with respect to the measuring unit 35 at predetermined intervals. By performing the measurement, it is possible to measure the temperature by accurately associating the correspondence relationship between the actual temperature and the reflectance of the sample 11 where it is difficult to measure the temperature accurately. Further, when the sample 11 is heated, the sample 11 is heated to a temperature equal to or higher than the heating temperature by the recording laser beam at the time of recording the recording data on the optical recording medium 1 as a product, under the condition that matches the usage state of the optical recording medium 1 as a product. The reflectance can be measured with, which enables more accurate selection of the recording material. In this case, the base material 2
By using the glass plate (glass base material) as A, the deformation of the sample 11 during the heating by the heater 41a is prevented, and thus the reflectance of the sample 11 can be accurately measured. Further, according to the reflectance measuring device 31, the spectroscope 42a is configured to be able to selectively emit the emission laser La in an arbitrary wavelength range with respect to the sample 11, thereby using the optical recording medium 1 as a product. Since the reflectance can be measured under the condition that matches the state (recording condition), the recording material can be selected accurately.

Further, according to this reflectance measuring device 31,
When the control unit 37 causes the measuring unit 35 to measure the reflectance at each predetermined temperature and satisfies the condition defined in the discrimination data stored in the ROM 39, the recording material is used for recording for the optical recording medium 1. By displaying on the display unit 36 that the layer 4 has the suitability for forming, the operator can select a recording material based on the measurement result (reflectance change characteristic) in a short time. Moreover, it is possible to accurately determine whether or not the material is suitable as a recording material. Further, according to this reflectance measuring device 31, the control unit 37
The reflectance for sample 11 at the first temperature and the second
It is possible to determine that the recording layer 4 of the sample 11 is suitable as a recording film for an optical recording medium by appropriately defining the difference from the reflectance of the sample 11 at the temperature of 1. A recording material that can ensure the reading of the mark can be selected.

The present invention is not limited to the above-described embodiments of the invention, and can be modified as appropriate. For example, in the embodiment of the present invention, an example in which the sample 41 is heated by the heater 41a of the heating stage 41 in the optical microscope 32 has been described, but the present invention is not limited to this and, for example, in a test apparatus (box). The sample 11 may be heated by raising the room temperature in the test apparatus with various heating means while the sample 11 is set. Further, the emission of the emission laser La to the sample 11 and the reception of the reflection laser Lb reflected by the sample 11 are not limited to the emission and the reception via the optical system 42 in the optical microscope 32, and the above-described test apparatus is used. Alternatively, the emission laser La may be directly emitted from the laser emission unit 33, and the reflected laser Lb reflected by the sample 11 may be directly received by the laser reception unit 34. Further, the means for extracting a laser beam in an arbitrary wavelength region from the laser beam L is not limited to the spectroscope 42a in the optical system 42,
By adopting a laser capable of emitting the emission laser La in various wavelength regions as the laser emission unit 33, it is possible to emit the emission laser La in any wavelength region.

In the embodiment of the present invention, the first sub-recording film 4a and the second sub-recording film 4 are used as the objects of reflectance measurement.
Although the example of measuring the reflectance of the recording layer 4 composed of two thin films of b has been described, the recording film in the present invention is not limited to this, and recording films having various structures can be measured. For example, a recording film composed of three or more kinds of thin films or 1
It is possible to measure various recording films such as a recording film in which small pieces of different materials are mixed in one thin film. The material of the recording film (recording material) is not limited to the metal material exemplified in the embodiment of the present invention, and various materials can be used. Further, in the embodiment of the present invention, an example in which the emission laser La is made incident on the sample 11 from the side opposite to the direction in which the base material 2 exists with respect to the recording layer 4 has been described. It is also possible to measure the reflectance of the recording film in the recording medium having a structure in which the reflected laser beam Lb is reflected on the side of the base material 2A when incident. Further, the materials used in the embodiments of the present invention and the evaluations for the materials are merely examples, and even materials that are not preferable as recording materials in the embodiments of the present invention are manufactured using the materials. It can be preferably used depending on the configuration of the system using the recording medium and the actual structure of the recording medium. Therefore, the judgment results for various materials in the embodiments of the present invention are examples for facilitating understanding of the reflectance measuring method according to the present invention, and do not mean assertive results for the materials. Absent.

[0041]

As described above, according to the reflectance measuring method of the present invention, the reproducing laser beam is emitted toward the recording film while applying heat from the heating element to the recording film formed on the substrate. Then, by measuring the reflectance of the recording film at each predetermined temperature, it is not necessary to form the grooves and lands necessary for irradiating the recording laser beam on the base material, and moreover, the film such as the cover layer is formed. As a result, the manufacturing cost of the sample for reflectance measurement can be sufficiently reduced. In addition, the recording film formed on the substrate can be heated stepwise easily in a short time as compared with the conventional method of forming a recording mark by irradiating the recording laser beam. Therefore, the development cost of the optical recording medium can be sufficiently reduced. Moreover, since the state in which the irradiation power of the recording laser beam is changed in multiple stages can be reliably and easily reproduced by measuring the reflectance of the sample at each predetermined temperature, it is used for the sample. It is possible to accurately and quickly determine whether or not the recording material is suitable for forming a recording film for an optical recording medium. Therefore, the development cost of the optical recording medium can be sufficiently reduced.

In this case, by measuring the reflectance at predetermined time intervals while heating the recording film at a constant temperature rising rate, the reflectance can be measured by correctly associating the correspondence relationship between the temperature of the sample and the reflectance. it can.

Further, when the recording film is heated, the reflectance is measured by heating to a temperature not lower than the heating temperature by the recording laser beam at the time of recording the recording data on the optical recording medium having the recording film, and the optical recording medium as a product. As a result of being able to measure the reflectance under the conditions that match the usage state of, the recording material can be selected more accurately.
In addition, it is possible to select a recording material capable of forming a stable recording layer that is not affected by the difference in laser power when irradiated with laser beams of various laser powers in the state of being actually used for an optical recording medium.

Further, by measuring the reflectance of the recording film formed on the glass plate as the base material, it is possible to prevent the deformation of the base material when the sample is heated. The rate can be measured accurately. In addition, the optical characteristics of the recording film can be accurately measured by eliminating the influence of the presence of grooves and lands.

Further, according to the reflectance measuring apparatus of the present invention, the control section causes the heating means to heat the sample and causes the laser emitting section to emit a reproducing laser beam to the sample. It is necessary to irradiate the recording laser beam by sequentially measuring the reflectance for each predetermined temperature of the sample based on the light receiving level of the reproducing laser beam reflected by the sample and received by the laser receiving section. Since it is not necessary to form a groove and a land on the base material, and a film such as a cover layer is not necessary, the manufacturing cost of the reflectance measurement sample can be sufficiently reduced. Therefore, the development cost of the optical recording medium can be sufficiently reduced. Moreover, since the state in which the irradiation power of the recording laser beam is changed in multiple stages can be reliably and easily reproduced by measuring the reflectance of the sample at each predetermined temperature, it is used for the sample. It is possible to determine accurately and in a short time whether or not the recording material is suitable for forming the recording film for the optical recording medium. As a result, the development cost of the optical recording medium can be sufficiently reduced.

In this case, the control unit causes the heating means to heat the sample at a constant temperature rising rate and causes the measuring unit to measure the reflectance at predetermined time intervals so that the temperature of the sample corresponds to the reflectance. The relationships can be correctly associated to measure reflectance.

Further, the control unit causes the heating means to heat the sample to a temperature equal to or higher than the heating temperature by the recording laser beam at the time of recording the recording data on the optical recording medium provided with the recording film of the sample and to reflect it to the measuring unit. By measuring the reflectance, as a result, the reflectance can be measured under the conditions that match the usage condition of the optical recording medium as a product,
The recording material can be selected more accurately. Further, it is possible to select a recording material capable of forming a stable recording layer that is not affected by the difference in laser power when irradiated with laser beams of various laser powers in a state of being actually used for an optical recording medium.

Further, according to the reflectance measuring apparatus of the present invention, the laser emitting section is configured to selectively emit the reproducing laser beam in an arbitrary wavelength range to the sample, so that the light as a product can be obtained. Since the reflectance can be measured under a condition (reproducing laser beam used for reading recorded data) that matches the usage condition (recording condition) of the recording medium, the recording material can be selected more accurately. .

Further, according to the reflectance measuring apparatus of the present invention, the material used for the sample based on the reflectance measured by the control unit at each predetermined temperature and the discrimination data stored in the storage unit. The suitability of the recording material is displayed and the result of the determination is displayed on the display unit. In comparison with the operator selecting the recording material based on the measurement result (change characteristics of reflectance), the recording material can be used in a shorter time. It is possible to accurately determine the suitability for.

In this case, the storage unit stores the reflectance of the sample at the first temperature and the second reflectance at a temperature higher than the first temperature.
By storing the reflectance data for discriminating whether or not the sample has suitability by appropriately defining the difference with the reflectance for the sample at the temperature of, as the discrimination data,
It is possible to select a recording material capable of ensuring the reliable reading of the recording mark, and thus it is possible to develop an optical recording medium capable of ensuring the reliable reading of the recording mark.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an optical recording medium 1 which is an example of an optical recording medium developed by using a reflectance measuring method according to an embodiment of the present invention.

FIG. 2 is a recording layer 4 and a protective layer 5 in the optical recording medium 1.
2A is a cross-sectional view of the film structure of FIG. 2A before emission of a recording laser beam (before recording), and FIG. 6B is a cross-sectional view after emission of a recording laser beam (after recording).

FIG. 3 is a reflectance measuring device 31 according to an embodiment of the present invention.
3 is a block diagram showing the configuration of FIG.

FIG. 4 is a recording layer 4 (first sub-recording film 4a) whose reflectance is to be measured.
9 is a cross-sectional view of Sample 11 having a second sub-recording film 4b) formed thereon.

FIG. 5 is a characteristic diagram showing reflectance change characteristics of a sample 11 whose reflectance is measured by a reflectance measuring device 31.

FIG. 6 is a characteristic diagram showing reflectance change characteristics of another sample 11 whose reflectance is measured by a reflectance measuring device 31.

[Explanation of symbols] 1 Optical recording medium 2,2A base material 3 reflective layer 4 recording layers 4a First sub-recording film 4b Second sub-recording film 5 protective layer 5a First protective film 5b Second protective film 6 cover layers 11 samples 31 Reflectance measuring device 32 Optical microscope 33 Laser emitting part 34 Laser receiver 35 Measuring unit 36 Display 37 Control unit 38 RAM 39 ROM 41 heating stage 41a heater 41b Power supply unit 42 Optical system 42a spectroscope M recording section L laser beam La emission laser Lb reflection laser

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G059 AA02 AA05 BB10 BB16 DD16                       EE02 FF03 FF04 FF05 GG01                       JJ01 KK01 MM05 MM10 PP04                 5D121 AA01 HH11 HH18

Claims (4)

[Claims] 1. A film containing N kinds of materials (N is a natural number of 2 or more) is formed, and the atomic arrangement is changed by the irradiation of the recording laser beam, so that the reflectance for the reproducing laser beam of a predetermined wavelength is increased. A reflectance measuring method for measuring the reflectance of a recording film for an optical recording medium which changes, wherein the recording film formed on a substrate is heated toward the recording film by applying heat from a heating element to the recording film. A reflectance measuring method for emitting a reproducing laser beam to measure the reflectance of the recording film at a predetermined temperature. 2. A reflectance for a reproducing laser beam having a predetermined wavelength is formed by forming a film containing N kinds of materials (N is a natural number of 2 or more) and changing the atomic arrangement by irradiation of the recording laser beam. A reflectance measuring device for measuring the reflectance of a recording film for a changing optical recording medium, wherein a sample having the recording film formed on a substrate is heated by heating a heating element. Heating means, a laser emitting part for emitting the reproducing laser beam to the sample, a laser receiving part for receiving the reproducing laser beam reflected by the sample, and the reproducing received by the laser receiving part. Unit for measuring the reflectance of the sample based on the received level of the laser beam for use, the heating unit, the laser emitting unit, the laser receiving unit, and And a control unit for controlling the measuring unit, wherein the control unit causes the heating unit to heat the sample, and causes the laser emission unit to emit the reproduction laser beam to the sample. A reflectance measuring device for sequentially measuring the reflectance for each predetermined temperature of the sample based on the light receiving level of the reproducing laser beam reflected by the sample and received by the laser light receiving section with respect to the measuring section. 3. The reflectance measuring apparatus according to claim 2, wherein the laser emitting section is configured to be capable of selectively emitting the reproducing laser beam in an arbitrary wavelength region with respect to the sample. 4. A display unit for displaying predetermined information on the recording film, and a storage unit for storing discrimination data for discriminating the suitability of the recording film as a recording film for an optical recording medium, The controller determines the suitability of the material used in the sample as the recording film based on the reflectance measured at each of the predetermined temperatures and the determination data stored in the storage. The reflectance measuring device according to claim 2, wherein the determination result is displayed on the display unit.