JP2002260224A - Optical disk inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk inspection device which can easily decide whether the recording characteristics of the optical disk is satisfactory. SOLUTION: This device is a device for inspecting the recording characteristics of the optical disk. In addition, a mean value computing part which computes a mean value by reading a reflected light from the optical disk; a judgement value recording part which records a judgement value by which the recording characteristics of the optical disk is decided to be unsatisfactory; a decision part which reads the reflected light in a prescribed section from the optical disk, integrates the sections which are out of a preliminarily fixed threshold value and decides whether the integrated value is larger than the judgement value recorded in the control value recording part; and a control part which outputs the result of the decision made by the decision part are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk inspection apparatus for inspecting the recording characteristics of an optical disk.

[0002]

2. Description of the Related Art As an optical disc for recording / reproducing by irradiating a laser beam, C which can be recorded only once (recordable type)
D-R, DVD-R, rewritable CD-RW, D
Various media such as VD-RW, DVD-RAM, MO, MD, etc. have been put into practical use.
Demand is increasing year by year in place of magnetic recording media such as cassette tapes and floppy (registered trademark) disks.

[0003] In these optical discs, information is recorded and the information is reproduced and used. Therefore, it is an important requirement to maintain a low read error during reproduction to maintain quality. However, the method of actually writing information on a recording medium and measuring a read error as a quality inspection method changes the state of the recording medium. In particular, a write-once recording medium is a destructive inspection, and is used for inspection. The used media cannot be reused.

Therefore, conventionally, a method of measuring the size and quantity of a defect using a line sensor camera or the like, and a method of measuring the size and quantity of a fine defect using a laser beam have been used.

[0005]

However, in the conventional method, it is difficult to accurately measure the size of a defect, and it takes a long time for inspection. SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk inspection apparatus that can easily determine whether or not recording characteristics are good.

[0006]

According to a first aspect of the present invention, there is provided an optical disk inspection apparatus for inspecting recording characteristics of an optical disk, comprising: an average value calculating unit for reading reflected light from the optical disk and calculating an average value; A determination value recording unit that records a determination value at which a recording characteristic of the optical disc is rejected, and reads reflected light from the optical disc in a predetermined section, integrates a section outside a predetermined threshold, and integrates. A determination unit that determines whether a value is greater than a determination value recorded in the determination value recording unit; and a control unit that outputs a determination result of the determination unit.

[0007] In the invention according to claim 2, the determining section sets a predetermined time instead of the predetermined section, and integrates the time outside the threshold. In the invention according to claim 3, the predetermined section in which the determination unit makes a determination is set to 1.5 to
32 μm or the time for passing through the section.

[0008] In the invention according to claim 4, the threshold value is set as follows:
When the linear velocity is 7 m / s, ± 12% or more of the average value of the reflected light
± 23%. In the invention according to claim 5, the threshold value is set to ± 1 of the average value of the reflected light when the linear velocity is 14 m / s.
7% to ± 26%.

In the invention according to claim 6, when the control section determines that the value is larger than the judgment value, the control section outputs an inspection failure and stops the operation of the judgment section, and the operation of the judgment section is smaller than the judgment value. Is determined, the operation of the determination unit is repeated until the inspection of the entire surface of the optical disk is completed.

[0010] In the invention according to claim 7, the optical disk to be inspected includes Sb, T as a constituent element as a recording layer material.
e, and the composition ratio Sb _x Te _100-x (x is atomic%)
Is 40 ≦ x ≦ 80, and as an additional element, G
The optical disk has a phase-change recording layer containing at least one of a, Ge, Ag, In, Bi, C, N, O, Si, and S.

In the invention according to claim 8, the optical disk to be inspected comprises a cyanine dye, a phthalocyanine dye, a naphthalocyanine dye, a naphthoquinone / anthraquinone dye, a triallylmethane dye, a squarylium dye as a recording layer material. An optical disk having an organic dye-based write-once recording layer containing at least one compound among a dye, a pyrylium-based dye, an azurenium-based dye, and an azo-based dye is provided.

[0012]

1 to 3 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a configuration diagram of an embodiment of the present invention,
2 and 3 are operation flowcharts of the embodiment. FIG. 1 shows a main part according to the present invention, wherein 1 is an optical disk to be inspected, 2 is a motor for rotating the optical disk 1, and 3 is a pickup for irradiating the optical disk 1 with laser light and receiving its reflected light. .

4 is a judgment value recording unit, 5 is an average value calculation unit, 6 is an input unit, 7 is a judgment unit, 8 is a display unit, 9 is a control unit, 10 is an interface (I / O), and 11 is processing. Is a processor (CPU) that performs the following.

Before describing the operation of the embodiment of the present invention, the principle will be described first. When information is recorded on an optical disk, if the optical disk has a defect, an error occurs when the recorded information is read.

Even if 1000 errors occur in the information read from the optical disk, if the 1000 errors are dispersed throughout the optical disk, the error can be corrected by performing error correction. The recording of such information is performed with error correction.

However, when errors are concentrated, errors cannot be corrected. Therefore, the recording characteristics of the optical disc are divided into predetermined sections, and the evaluation is made based on the ratio of errors occurring in the divided sections. If the error rate is equal to or less than the standard value, the optical disc is determined to be good.

As a method for estimating whether or not the error rate is equal to or less than a standard value without recording information on the optical disk to be inspected, in the present invention, the error is estimated from the reflected light of the light applied to the optical disk.

[0018] That is, as shown in FIG. 4, the V-Δ~V + V (Δ to the mean value V of the reflected light in the reflected light (which may be or interval) predetermined time level T ₀ The time (T ₁ + T ₂ + T ₃ + T ₄ ) outside the threshold is integrated, and if the integrated value is equal to or greater than a predetermined value, it is determined that the standard value is not satisfied.

According to the experiment, the optical disk is a 1.5~3μm length to move on pickup T ₀ hours, delta
Is 12% to 23% of the average value V when the linear velocity is 7 m / s,
When the linear velocity is 14 m / s, Δ is 17% to 26% of the average value
Then, as shown in FIG. 5, it was obtained that the relationship between the read error rate and the defect rate was substantially linear.

[0020] relationship correlation coefficient read false rate and defect rates R ² and threshold delta (%) results are obtained as shown in FIG. 6, the threshold delta when the linear velocity of 7m / s 12% ~23 % When the linear velocity is 14 m / s, and when the linear velocity is 14 m / s, the correlation is 0.8 or more within the range of 17% to 26%.

In the present invention, the time corresponding to the defect rate corresponding to the reading error rate as standardized in FIG. 5 is recorded in advance in the judgment value recording unit 4 based on the experimental results obtained in this manner. Next, the operation of the embodiment will be described with reference to FIGS.

In step S1, the control unit 9 controls the motor 2
Is rotated at the designated speed, and the process proceeds to step S2, where the average value calculation unit 5 positions the pickup 3 at a predetermined position on the optical disc 1.

In step S3, the average value calculation section 5 irradiates the optical disk 1 with laser light from the pickup 3 while tracking the pickup 3 with respect to the track of the optical disk 1, receives the reflected light, and proceeds to step S4.
Move to and record the received light value.

In step S5, the average value calculation section 5 determines whether or not a predetermined time has elapsed since the first light reception, and steps S3 to S5 are repeated until the predetermined time has elapsed. In step S6, the average value calculation unit 5 calculates and records the average value V of the received light values recorded in step S4.

Although the average value calculating section 5 calculates the average value for a predetermined time, the average value may be calculated by moving the pickup 3 from the innermost circumference to the outermost circumference of the optical disk 1. However, this method takes a long time.

In step S7, the control section 9 positions the pickup 3 at the innermost circumference of the optical disc 1. In step S8, the determination unit 5 starts a timer T (not shown), and proceeds to step S9, where the integration timer T (not shown) is started.
Reset T.

In step S10, the determination section 7 receives the reflected light from the pickup 3, and proceeds to step S11 to determine whether or not the received value is in the range of V-Δ to V + Δ. V is the average value calculated in step S6,
Δ is the above-described threshold value, and the ratio to V is determined in advance in the determination value recording unit 4 corresponding to the linear velocity.

If the determination in step S11 is NO, that is, if it is determined that the value is out of the range of V-Δ to V + Δ, the process proceeds to step S12, in which the integration timer TT is started to measure time, and the determination in step S12 is YES. In the case of, the process proceeds to step S13, and the counting of the integration timer TT is stopped.

In step S14, the determination section 7 determines whether or not the time counted by the timer T has reached T _0.
In the case of O, the process proceeds to step S10 and steps S10 to S
Repeat 14.

If the determination in step S14 is YES, the process proceeds to step S15, where the determination unit 7 determines whether the integration timer TT
It is determined whether or not the integration time is larger than TT ₀ recorded in the determination value recording unit 4. If the determination is YES, that is, if it is determined to be large, the process proceeds to step S16, and the control unit 9
Displays the inspection failure on the display unit 8 and ends the inspection.

If the determination in step S15 is NO, the process proceeds to step S17, where the pickup 3
It is determined whether or not the outermost circumference has been reached. If the outermost circumference has not been reached, the process moves to step S8 and steps S8 to S17 are repeated, and the inspection in the next section is continued.

If the determination in step S17 is YES, the process moves to step S18, where the display 8 indicates that the inspection has passed, and the inspection ends. In the embodiment, the defective portion is integrated by time, but the length of the defective portion may be integrated.

FIG. 7 shows an embodiment of an optical disk suitable for the present invention. The basic configuration is a transparent substrate 21 having a guide groove.
Recording layer 23, reflective heat dissipation layer 25, overcoat layer 26
Having. Protective layers 22 and 24 may be provided below and / or above the recording layer. Further, a printing layer 28 is formed on the overcoat layer, and a hard coat layer 2 is formed on the mirror side of the substrate.
7 may be provided.

The above-mentioned single-plate disk may have a laminated structure with an adhesive layer 29 interposed therebetween. The disc on the opposite side to be bonded may be a similar single-plate disc or a transparent substrate only. Alternatively, the single-layer disc may be bonded without forming a printed layer, and the printed layer 28 'may be formed on the opposite side after bonding.

The material of the substrate is usually glass, ceramics, or resin, and a resin substrate is suitable in terms of moldability and cost. Examples of resins include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin,
Examples include acrylonitrile-styrene copolymer resin, polyethylene resin, polypropylene resin, silicone resin, fluorine resin, ABS resin, urethane resin, etc., polycarbonate resin and acrylic resin which are excellent in moldability, optical properties and cost. Is preferred.

For the recording layer, different materials are used for the write-once optical information recording medium and the rewritable optical information recording medium. In the case of a write-once optical information recording medium, as a recording layer material, a cyanine dye, a phthalocyanine dye, a naphthalocyanine dye, a naphthoquinone / anthraquinone dye, a triallylmethane dye, a squarylium dye, a pyrylium dye, An organic dye material containing at least one compound of the azurenium-based dye and the azo-based dye is suitable for obtaining good recording characteristics. The recording layer made of an organic dye material can be formed by dissolving in a single or mixed solvent such as an alcohol solvent, an ether solvent, a cellosolve solvent, and a hydrocarbon solvent, and spin-coating the solution. The film thickness is 10
500 nm is preferable, and more preferably, 50 to 300 nm.
nm is desirable. When the thickness is less than 10 nm, the light absorption ability is remarkably reduced, and does not serve as a recording layer. 5
If the thickness is larger than 00 nm, the amount of light absorption in the recording layer is large, and a sufficient reflectance cannot be secured.

As the recording layer of the rewritable optical information recording medium, a phase-change recording material utilizing a transition between a crystal and an amorphous phase or a transition between a crystal and a crystal phase, and a magneto-optical recording utilizing a Kerr effect of a perpendicular magnetization film. Although materials are used, phase-change optical information recording media are particularly easy to overwrite with a single beam, which is difficult with magneto-optical optical information recording media. Because of its simplicity, it is used in rewritable CDs and DVDs.
The recording material of the phase-change type optical information recording medium includes Sb and Te which cause a phase change between a crystalline phase and an amorphous phase and can take a stabilized or meta-stabilized state, and have a composition ratio of Sb _x Te _{100. -x} (x is atomic%) is 40
A phase change type recording material in which ≦ x ≦ 80 is suitable because of good recording (amorphization) sensitivity / speed, erasing (crystallization) sensitivity / speed, and erasing ratio. Ga, Ge, Ag, In, Bi, C, N, O, S
By adding elements such as i and S, the recording / erasing sensitivity, signal characteristics, reliability, and the like can be improved. Therefore, the characteristics of the optical information recording medium can be controlled by the added elements and their composition ratios. it can. The addition ratio of various elements is 0.1
-20 at%, preferably 0.1-15 at%.

The thickness of the phase-change recording phase is 10 to 50.
nm, preferably 12 to 30 nm. Further, in consideration of initial characteristics such as jitter, overwrite characteristics, and mass production efficiency, the thickness is preferably 14 to 25 nm. If the thickness is less than 10 nm, the light absorbing ability is remarkably reduced, and does not serve as a recording layer. On the other hand, if the thickness is more than 50 nm, uniform phase change at high speed is unlikely to occur. Such a phase-change recording phase can be formed by various vapor phase growth methods, for example, a vacuum deposition method, a sputtering method, a plasma CVD method, and a light CV method.
It can be formed by a D method, an ion plating method, an electron beam evaporation method, or the like. In particular, the sputtering method
Excellent mass productivity, film quality, etc.

A protective layer is formed below and above the phase change recording layer. The material of the protective layer is Si
O, SiO ₂ , ZnO, SnO ₂ , Al ₂ O ₃ , TiO
Metal oxides such as ₂ , In ₂ O ₃ , MgO, ZrO ₂ ,
Nitrides such as Si ₃ N ₄ , AlN, TiN, BN and ZrN; sulfides such as ZnS, In ₂ S ₃ and TaS ₄ ;
Examples thereof include carbides such as C, TaC, BC, WC, TiC, and ZrC, diamond-like carbon, and mixtures thereof. These materials can be used alone as a protective layer, or as a mixture of each other. If necessary, impurities may be contained. Further, a structure in which two or more layers are stacked instead of a single layer may be employed. However, the melting point of the protective layer is
It must be higher than the phase change recording layer. Such a protective layer can be formed by various vapor deposition methods, for example, a vacuum deposition method, a sputtering method, a plasma CVD method, a photo CVD method, an ion plating method, an electron beam deposition method, or the like. Among them, the sputtering method is excellent in mass productivity, film quality, and the like.

The thickness of the lower protective layer greatly affects the reflectance, the degree of modulation, and the recording sensitivity. In order to obtain good signal characteristics, the thickness is required to be 60 to 120 nm. The thickness of the upper protective layer is 5 to 45 nm, preferably 7 to 40 nm.
nm. If it is thinner than 5 nm, it will not function as a heat-resistant protective layer. Also, the recording sensitivity is reduced. On the other hand, if the thickness is more than 45 nm, interface peeling is liable to occur, and the repetitive recording performance also decreases.

As the reflective heat dissipation layer, Al, Au, Ag,
Metal materials such as Cu, Ta, Ti, and W, or alloys containing these elements can be used. In addition, elements such as Cr, Ti, Si, Cu, Ag, Pd, and Ta may be added to the above-described materials in order to improve corrosion resistance and thermal conductivity. The addition ratio is 0.3 to 2 at.
% Is suitable. If less than 0.3 at%,
Poor effect on corrosion resistance. If it exceeds 2 at%, the thermal conductivity becomes too high, and it becomes difficult to form an amorphous state. Such a reflective heat dissipation layer can be formed by various vapor deposition methods, for example, a vacuum deposition method, a sputtering method, a plasma CVD method,
It can be formed by a photo CVD method, an ion plating method, an electron beam evaporation method, or the like. The thickness of the alloy or metal layer is 50 to 200 nm, preferably 70 to 160 nm.
Good to be. It is also possible to make the alloy or metal layer multilayer. In the case of multilayering, the thickness of each layer needs to be at least 10 nm or more, and the total thickness of the multilayered film is preferably 50 to 160 nm.

An overcoat layer is formed on the reflective heat dissipation layer to prevent its oxidation. As the overcoat layer, an ultraviolet curable resin produced by spin coating is generally used. Its thickness is suitably 3 to 15 μm.
If the thickness is less than 3 μm, an increase in error may be observed when a printing layer is provided on the overcoat layer. On the other hand, if the thickness is more than 15 μm, the internal stress increases, which greatly affects the mechanical properties of the disk.

As the hard coat layer, an ultraviolet curable resin produced by spin coating is generally used. Its thickness is suitably from 2 to 6 μm. If it is thinner than 2 μm,
Sufficient scratch resistance cannot be obtained. If it is thicker than 6 μm,
The internal stress increases, which greatly affects the mechanical properties of the disk. The hardness must be equal to or higher than H, which is a pencil hardness that does not cause significant damage even when rubbed with a cloth. It is also effective to mix a conductive material as needed to prevent static charge and to prevent adhesion of dust and the like.

The printing layer is used for the purpose of ensuring abrasion resistance, label printing of a brand name or the like, formation of an ink receiving layer for an ink jet printer, and the like. In general, an ultraviolet curable resin is formed by a screen printing method. It is. Its thickness is suitably 3 to 50 μm. When the thickness is less than 3 μm, unevenness occurs at the time of layer formation. 50μ
If the thickness is larger than m, the internal stress increases, which greatly affects the mechanical properties of the disk.

As the adhesive layer, an adhesive such as an ultraviolet curable resin, a hot melt adhesive, and a silicone resin can be used. The material of such an adhesive layer is applied to the overcoat layer or the print layer by a method such as spin coating, roll coating, or screen printing depending on the material, and is subjected to treatment such as ultraviolet irradiation, heating, and pressing. Go and glue it to the disc on the other side. The disk on the opposite side may be a similar single-plate disk or only a transparent substrate, and the bonding surface of the opposite side disk may or may not be coated with a material for the adhesive layer. Further, an adhesive sheet can be used as the adhesive layer. Although the thickness of the adhesive layer is not particularly limited, it is preferably 5 to 100 μm in consideration of the influence of the coating properties of the material, the curability, and the mechanical properties of the disk. The range of the adhesive surface is not particularly limited,
When applied to an optical information recording medium compatible with DVD and / or CD, the position of the inner peripheral end is desirably Φ15 to 40 mm, preferably Φ15 to 30 mm in order to secure the adhesive strength.

[0046]

As described above, the reflected light from the optical disc in the predetermined section is read, the sections outside the predetermined threshold value are integrated, and if the integrated value is larger than the judgment value, it is out of the standard. , It is possible to easily determine whether or not the recording characteristics are good.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an operation flowchart of the embodiment.

FIG. 3 is an operation flowchart of the embodiment.

FIG. 4 is a diagram illustrating an average value, a threshold value, a predetermined section, and a section to be integrated.

FIG. 5 is a diagram showing a relationship between a read error rate and a defect rate.

FIG. 6 is a diagram showing a relationship between a threshold and a correlation coefficient between a read error rate and a defect rate.

FIG. 7 is a diagram showing an embodiment of an optical disc.

[Explanation of symbols]

 Reference Signs List 1 optical disk 2 motor 3 pickup 4 judgment value recording section 5 average value calculation section 6 input section 7 judgment section 8 display section 9 control section 10 interface (I / O) 11 processor (CPU)

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl. ⁷ identification mark FI theme Court Bu (reference) B41M 5/26 Y F-term (reference) 2H111 EA03 EA04 EA22 EA23 FB05 FB09 FB10 FB12 FB18 FB21 FB29 FB30 FB42 FB45 FB46 FB48 5D029 JA01 JA04 5D090 AA01 BB03 BB05 CC14 CC16 CC18 DD01 FF37 HH01 JJ11 LL08 LL09 5D121 AA01 HH01 HH11 HH18

Claims (8)

[Claims] 1. An optical disk inspection apparatus for inspecting recording characteristics of an optical disk, comprising: an average value calculating unit that reads reflected light from the optical disk and calculates an average value; A reflected value from the optical disk in a predetermined section, and integrates a section outside a predetermined threshold, and the integrated value is recorded in the determination value recording section. An optical disc inspection device, comprising: a determination unit that determines whether the value is larger than a determination value; and a control unit that outputs a determination result of the determination unit. 2. The optical disk inspection apparatus according to claim 1, wherein the determination section sets a predetermined time instead of the predetermined section, and integrates a time outside the threshold. 3. The optical disk inspection apparatus according to claim 1, wherein the predetermined section in which the determination section makes a determination is set to 1.5 to 32 μm or a time passing through the section. 4. When the linear velocity is 7 m / s,
4. The optical disk inspection apparatus according to claim 1, wherein the average value of the reflected light is set to ± 12% to ± 23%. 5. The optical disk inspection apparatus according to claim 1, wherein the threshold is set to ± 17% to ± 26% of the average value of the reflected light when the linear velocity is 14 m / s. . 6. The control unit outputs an inspection failure when the determination unit determines that the value is larger than a determination value, stops the operation of the determination unit, and determines that the determination unit determines that the value is smaller than the determination value. The operation of the determination unit is repeated until inspection of the entire surface of the optical disc is completed,
An optical disk inspection apparatus according to 2, 3, 4, or 5. 7. The optical disk to be inspected contains Sb and Te as constituent elements as a recording layer material, and has a composition ratio Sb
_x Te _100-x (x is atomic%) is 40 ≦ x ≦ 80,
Further, Ga, Ge, Ag, In, B
7. The optical disk inspection apparatus according to claim 1, wherein the optical disk has a phase change type recording layer containing at least one element among i, C, N, O, Si, and S. . 8. The optical disk to be inspected, wherein the recording layer material comprises a cyanine dye, a phthalocyanine dye, a naphthalocyanine dye, a naphthoquinone / anthraquinone dye, a triallylmethane dye, a squarylium dye, a pyrylium dye, 7. The optical disk inspection apparatus according to claim 1, wherein the optical disk has an organic dye-based write-once recording layer containing at least one compound selected from an azurenium-based dye and an azo-based dye.