JP2005276262A - Method and device for inspecting optical laminate, and method and device for manufacturing optical laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily inspect the state of the second (deep side seen from recording/reproducing light) of an optical laminate, which is constituted of a pigment and a dielectric. <P>SOLUTION: A light emitted from the light emitting diode 1 of a light source is passed through a condenser lens 2 to become a parallel light, and then passed through a beam splitter 3, whereby the light of intensity of about 50% is made incident on the second substrate of an optical laminate 4. A remaining light split by the beam splitter 3 is monitored by an incident light photosensor 5 to measure incident light intensity. The light reflected on the surface of the second substrate of the optical laminate 4 is passed through the beam splitter 3 again, and received by a reflected light photosensor 6 to measure reflected light intensity. In an inspection part 9, the incident light intensity of the incident light photosensor 5 and the reflected light intensity of the reflected light photosensor 6 are compared with each other to obtain reflectance at the emission wavelength of the light emitting diode 1, and the thickness of a film formed in the optical laminate 4 is measured based on the reflectance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminate thickness obtained by sequentially laminating a reflective layer and an organic dye on a substrate, or a dye film thickness and / or a dielectric in a laminate obtained by sequentially laminating a reflective layer, an organic dye and a dielectric on a substrate. The present invention relates to an optical laminate inspection method and apparatus for inspecting film thickness, and an optical laminate manufacturing method and apparatus thereof.

  In general, CD-R, DVD + R, DVD-R, and the like are known as write-once type optical recording media capable of recording information only once with a laser beam. These write-once optical recording media have a structure in which a recording layer made of an organic dye is spin-coated on a transparent polycarbonate substrate on which a tracking groove is formed, and a light reflecting layer made of gold or silver is deposited thereon by sputtering. Further, a protective layer made of an ultraviolet curable resin is laminated. DVD + R and DVD-R have a structure in which two substrates having a thickness of 0.6 mm are bonded together, and have a large recording capacity.

  As a method for inspecting the film thickness of an organic dye recording film in the process of manufacturing these write-once type optical recording media, Patent Document 1 discloses a method for measuring the film thickness with transmitted or reflected light diffracted by a groove.

  Patent Document 2 discloses that the land portion film thickness and the groove portion film thickness are measured from diffracted lights of different orders, and the transmittance and diffracted light intensity are measured in a state where a dye film is formed on the substrate. It is disclosed to inspect the pigment film thickness.

  Further, Patent Document 3 discloses an apparatus for inspecting a defect with reflected light using light mainly composed of a characteristic absorption wavelength of a dye as inspection light.

  By the way, as a read DVD-ROM, one having two information recording layers is commercially available in order to increase the recording capacity. The two information recording layers are bonded to each other by sandwiching a transparent intermediate layer formed of an ultraviolet curable resin between the first substrate and the second substrate, and the first information layer is formed on the inner surface of the first substrate on which the concave and convex pits are formed. The first information layer recording layer L0 on which the semitransparent layer is formed, and the second information layer recording layer L1 formed on the transparent intermediate layer and the second metal reflection layer thereon. The translucent layer is formed using a dielectric film or a thin metal film.

  A laser beam that is reproduction light is focused so as to be condensed on the first information recording layer or the second information recording layer, respectively, and reflected light from the information recording layer is detected. The signal can be reproduced. Since signals are read from the two information recording layers, a maximum storage capacity of about 8.5 GB can be obtained.

In recent years, development of an optical recording medium having two recording layers and reproducing compatibility with a dual-layer DVD-ROM has been progressing. As this type of optical recording medium, a transparent substrate on which a groove is formed is used. An organic dye recording layer is formed, a translucent reflective layer is formed thereon, a total reflection layer is formed on a first substrate coated with an ultraviolet curable resin, and a substrate on which a groove is formed. What is manufactured by bonding a second substrate on which a dye recording layer is formed and a transparent inorganic thin film is formed through an adhesive is being put into practical use (see Patent Documents 4 and 5).
Japanese translation of PCT publication No. 2002-510107 JP 2002-367244 A Japanese Patent Laid-Open No. 11-66633 Japanese Patent Laid-Open No. 10-340483 JP 2000-31384 A

  However, when an optical recording medium is manufactured by forming and bonding a recording layer and a translucent reflective layer on each substrate as described above, the total reflection film of the second substrate does not transmit light. There is a problem that it is impossible to measure the film thickness of the dye formed on the total reflection film and the film thickness of the dielectric film formed on the dye with transmitted light.

  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 a second (back side as viewed from recording / reproducing light) recording layer comprising a dye and a dielectric of an optical laminate. An optical laminate inspection method capable of simply inspecting the state of an optical laminate, an optical laminate production method employing the method, an optical laminate inspection apparatus, and an optical laminate production apparatus employing the device It is in.

  In order to achieve the above object, an optical laminate inspection method and an optical laminate inspection apparatus according to the present invention measure the reflected light intensity of a laminate formed by sequentially laminating a reflective layer and an organic dye on a substrate, and a dye film It is characterized by inspecting the thickness.

  The optical laminate inspection method and the optical laminate inspection apparatus according to the present invention measure the reflected light intensity of a laminate formed by sequentially laminating a reflective layer, an organic dye, and a dielectric on a substrate, and the dielectric film thickness. It is characterized by inspecting.

  The optical laminate inspection method and optical laminate inspection apparatus according to the present invention are characterized by measuring the reflected light intensity of a specific wavelength and inspecting the film thickness.

  The optical laminate inspection method and the optical laminate inspection apparatus according to the present invention are characterized by measuring the reflected light intensity of light emitted from a light emitting diode having a specific wavelength and inspecting the film thickness.

  Further, the optical laminate inspection method and the optical laminate inspection apparatus according to the present invention provide a reflected light having a specific wavelength obtained by allowing light to enter the optical laminate and the light reflected by the optical laminate to be dispersed by a spectroscopic unit. It is characterized by measuring the strength and inspecting the film thickness.

  The optical laminate inspection method and optical laminate inspection apparatus according to the present invention are characterized in that a prism is used as the spectroscopic means.

  The optical laminate inspection method and optical laminate inspection apparatus according to the present invention are characterized in that a diffraction grating is used as the spectroscopic means.

  Also, the optical laminate inspection method and the optical laminate inspection apparatus according to the present invention inject light having a wavelength selected by the optical filter into the optical laminate, measure the reflected light intensity of the optical laminate, and inspect the film thickness. It is characterized by that.

  Further, the optical laminate inspection method and the optical laminate inspection apparatus according to the present invention are characterized in that the incident light is obliquely incident on the optical laminate, the reflected light intensity that is totally reflected is measured, and the film thickness is inspected. To do.

  Further, the optical laminate manufacturing method and the optical laminate manufacturing apparatus according to the present invention are characterized by receiving information on the dye film thickness and / or the dielectric film thickness obtained from the inspection result and controlling the film thickness. And

  According to the present invention, by measuring the reflectance spectrum of the optical laminate or the intensity of reflected light at a specific wavelength, even if the optical laminate has a configuration in which it is impossible to measure the film thickness with transmitted light. Therefore, it is possible to perform a highly accurate film thickness inspection.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing a first embodiment of the present invention applied to a second substrate inspection process in a two-layer write-once optical recording medium manufacturing system in order to explain the optical laminate inspection method and inspection apparatus of the present invention. FIG.

  In FIG. 1, light emitted from a light source 1 made of a light emitting diode (indicated by an arrow) passes through a condenser lens 2 to become parallel light, and then passes through a beam splitter 3 and has a light intensity of about 50%. Is incident on the second substrate of the optical laminate 4. The remaining light divided by the beam splitter 3 is monitored by the incident light photosensor 5 to measure the incident light intensity. The light reflected by the surface of the second substrate of the optical layered body 4 which is a two-layer write-once optical recording medium is again received by the reflected light photosensor 6 through the beam splitter 3 and the reflected light intensity is measured. At this time, it is conceivable to disperse light to a specific wavelength by disposing spectral means 7 and 8 such as prisms or diffraction gratings in the optical path before the light enters the photosensors 5 and 6.

  In the inspection unit 9, the reflectance at the light emission wavelength of the light emitting diode of the light source 1 is obtained by comparing the incident light intensity in the incident light photosensor 5 with the reflected light intensity in the reflected light photosensor 6.

  The two-layer write-once type optical recording medium, which is the optical layered body 4, is made of a metal such as Ag, Al, Au and Cu, Pd, Pt on a disk substrate on which tracking grooves having a depth of 20 to 200 nm and a pitch of 0.74 μm are formed. , Zn, In, Mg, Ti, V, Ta, and a total reflection made of an alloy to which 0.1 to 3 wt% is added is sputtered, and the maximum absorption wavelength of the light absorption spectrum of the film is 580 nm to 620 nm. A substrate (1) coated with an organic dye such as a tetraazaporphyrazine dye, a cyanine dye, an azo dye, a squarylium dye as a dye compound that easily obtains desired optical properties at a light wavelength (about 650 nm), or a dye, The transparent substrate is formed on the substrate (1) with an adhesive for bonding to the first substrate on which the semi-transmissive reflective film is formed so as not to elute the dye. A substrate formed with a dielectric (2).

  The transparent dielectric may be a dense thin film with good adhesion to the dye to protect the dye from the adhesive. However, the oxide such as silicon oxide, aluminum oxide, zinc oxide, titanium oxide, silicon nitride, nitride A nitride such as aluminum, a sulfide such as zinc sulfide, germanium sulfide, and molybdenum sulfide, a fluoride such as magnesium fluoride, cesium fluoride, and barium fluoride, and a mixture thereof can be used.

  Next, the measurement principle in the inspection unit 9 in this embodiment will be specifically described.

  Here, as for the absorbance and reflectance of the optical layered body 4, the spectral reflectance was measured using ETA-RT manufactured by Steag.

  The Ag total reflection film shows a high reflectance in the visible light region, but is slightly lower at a short wavelength and has a higher reflectance spectrum at a longer wavelength. When such an Ag reflective film is formed on a plastic substrate having grooves with an equal pitch, such as the optical laminate 4, a decrease in reflectance due to scattering by the grooves is observed.

  FIG. 2 is a spectral reflection spectrum of light that is vertically incident / reflected from the Ag reflecting film side of a substrate on which 140 nm of Ag is formed on a polycarbonate substrate on which grooves having a 0.74 μm pitch, a depth of 30 nm, and a width of 0.25 μm are formed. . In this case, a phenomenon in which the reflectance is reduced by 5 to 6% due to the scattering of the groove is observed near 750 nm.

  A squarylium dye recording layer is applied on the substrate by a spin coating method, and the maximum absorption wavelength λmax having a wavelength of 606 nm in the absorbance spectrum when directly applied to the substrate is used as a parameter as used in the production of a normal optical recording medium. When the film thickness was changed, a spectrum changing as shown in FIG. 3 was obtained. Under the same conditions, a pigment was applied on the substrate with the Ag reflecting film, and the reflection spectrum after annealing at 90 ° C. for 15 minutes was measured. As shown in FIG. 4, in the vicinity of 750 nm where the reflectance was reduced in FIG. Since the optical path length varies depending on the dye film thickness, the wavelength at which the reflectivity decreases is shifted. Accordingly, the dye film thickness on the Ag reflective film can be optically measured by measuring the minimum reflectance wavelength at 700 to 800 nm or by measuring the reflectance at 740 nm.

  Next, when a transparent dielectric is formed on the dye, the reflection spectrum is almost the same before and after the formation of the thin film on the transparent dielectric in the case of a low refractive index thin film having a refractive index of about 1.6 or less. When a high refractive index thin film of 8 or more is formed, the reflection spectrum changes greatly.

  When a transparent dielectric thin film having a refractive index of about 2.1 is formed on the dye, when the film thickness of the transparent dielectric thin film is changed, as shown in FIG. A change in the reflection spectrum was observed. As is clear from this, the film thickness of the transparent dielectric thin film can be optically measured by measuring the reflectance peak wavelength or reflectance near 490 nm or 660 nm.

  The method for measuring the dye film thickness and dielectric film thickness based on the reflected light spectrum of the optical layered body as described above can be used for general materials regardless of the dye material and dielectric material. It is only necessary to select an optimum wavelength accordingly.

  Further, as shown in FIG. 6, the measurement result after applying the dye obtained by the method and the apparatus 11 is fed back to the spinner device 12 constituting the optical laminate manufacturing apparatus, and the swing-off rotation speed or swing-off time is calculated. By providing the control unit 13 including a CPU (central processing unit) to be adjusted, a dye film recording film with very little dye film thickness variation can be obtained.

  Also, by feeding back the measurement result after dielectric film sputtering to a sputtering apparatus constituting the optical laminate manufacturing apparatus, a dye film recording film with very little dielectric / dye film thickness variation can be obtained. The optical recording medium produced in this way is unrecorded and has a very stable quality after recording.

  Moreover, in this embodiment, it is possible to use what mainly contains visible light wavelengths like a lamp | ramp.

  In addition, as shown in the schematic configuration diagram of the optical laminate inspection apparatus according to the second embodiment of the present invention shown in FIG. 7, when the measurement wavelength and the bandwidth are already determined, the bandpass filter transmits the desired wavelength. The use of 15 or the use of a light emitting diode as the light source can significantly reduce the device cost. In the following description, members corresponding to those described with reference to FIG.

  Furthermore, as in the schematic configuration diagram in Embodiment 3 of the optical laminate inspection apparatus of the present invention shown in FIG. 8, the same inspection is possible even with oblique incidence using the light-emitting diode 1 and the diffusion optical system.

  Hereinafter, the present invention will be described in more detail with reference to examples.

(Example 1)
A substrate having a guide groove uneven pattern having a depth of about 30 nm, a groove width of about 0.25 μm, and a track pitch of 0.74 μm is prepared on the surface of a polycarbonate substrate having a diameter of 120 mm and a thickness of 0.60 mm. (Product name: BigSpringer) Reflecting Ar0.98 / Cu0.02 in a thickness of about 140 nm under the conditions of sputtering gas 6.0 × 10 ⁻³ torr and DC sputtering power 3.5 kW using Ar as a sputtering gas. A layer was formed. Next, the squarylium dye compound was spin-coated on the reflective layer so that the absorption light intensity at λmax was 1.02, 1.06, 1.12 and 1.16.

  And as a result of measuring the pigment | dye surface reflectance of the said board | substrate of Example 1 by ETA-RT at wavelength 740nm, the result with a very high correlation like FIG. 9 was obtained.

(Example 2)
Furthermore, Ar was used as a sputtering gas on the dyed substrate prepared in Example 1 using a sputtering apparatus (product name: BigSpinter) under the conditions of sputtering pressure 4.0 × 10 ⁻³ torr and RF sputtering power 4.0 kW. Then, a dielectric was provided with a thickness of 120, 130, 140, and 150 nm of ZnS (80%) / SiO ₂ (20%) by sputtering.

  And as a result of measuring the dielectric film surface reflectance of the said board | substrate of Example 2 similarly to the above in wavelength 500nm, the result with a high correlation like FIG. 10 was obtained.

  The present invention is a CD-R / RW, DVD having a laminated structure in which a reflective layer and an organic dye are sequentially laminated on a substrate, or a laminated structure in which a reflective layer, an organic dye and a dielectric are laminated in order on a substrate. -Applied to inspection of the film thickness of a dye and / or dielectric in a two-layer write-once optical recording medium such as ROM, DVD + R / RW, DVD-R / RW, DVD-RAM, etc., and in particular, the film thickness is measured by transmitted light. It is effective when applied to an optical laminate that is impossible.

Schematic block diagram in Embodiment 2 of the optical laminated body inspection apparatus of this invention Diagram showing the relationship between reflectance and wavelength Diagram showing the relationship between absorbance and wavelength Diagram showing the relationship between reflectance and wavelength Diagram showing the relationship between reflectance and wavelength Simplified explanatory diagram of the control system in this embodiment Schematic block diagram in Embodiment 2 of the optical laminated body inspection apparatus of this invention Schematic block diagram in Embodiment 3 of the optical laminated body inspection apparatus of this invention The figure which shows the relationship between the reflectance of wavelength 740nm, and the light absorbency of wavelength 605nm. The figure which shows the relationship between the reflectance of wavelength 500nm, and dielectric material film thickness

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Condensing lens 3 Beam splitter 4 Optical laminated body 5 Incident light photosensor 6 Reflected light photosensor 7, 8 Spectroscopic means 9 Inspection part 11 Inspection apparatus 12 Manufacturing apparatus 13 Control part 15 Band pass filter

Claims (20)

  An optical laminate inspection method, comprising: measuring a reflected film intensity of a laminate obtained by sequentially laminating a reflective layer and an organic pigment on a substrate;   An optical laminate inspection method comprising: measuring a reflected film intensity of a laminate obtained by sequentially laminating a reflective layer, an organic dye, and a dielectric on a substrate, and examining the dielectric film thickness.   3. The optical laminate inspection method according to claim 1, wherein the reflected light intensity of a specific wavelength is measured and the film thickness is inspected.   3. The method for inspecting an optical laminate according to claim 1, wherein the intensity of reflected light of light emitted from a light emitting diode having a specific wavelength is measured to inspect the film thickness.   2. The film thickness is inspected by measuring the reflected light intensity of a specific wavelength obtained by making light incident on the optical laminate, spectroscopic means splitting the light after being reflected by the optical laminate, or 3. The optical laminate inspection method according to 2.   6. The optical laminate inspection method according to claim 5, wherein a prism is used as the spectroscopic means.   6. The optical laminate inspection method according to claim 5, wherein a diffraction grating is used as the spectroscopic means.   3. The optical laminate inspection method according to claim 1, wherein the light selected by the optical filter is incident on the optical laminate, the reflected light intensity of the optical laminate is measured, and the film thickness is inspected.   The optical laminate inspection method according to any one of claims 1 to 8, wherein the optical laminate is incident from an oblique direction, the reflected light intensity totally reflected is measured, and the film thickness is inspected.   An optical system characterized by receiving information on a dye film thickness and / or a dielectric film thickness obtained from an inspection result obtained by the optical laminate inspection method according to any one of claims 1 to 9, and controlling the film thickness. Laminate manufacturing method.   An optical laminate inspection apparatus comprising an inspection unit that measures the reflected light intensity of a laminate formed by sequentially laminating a reflective layer and an organic dye on a substrate and inspects the thickness of the dye.   An optical laminate inspection apparatus comprising an inspection unit that measures the reflected light intensity of a laminate formed by sequentially laminating a reflective layer, an organic dye, and a dielectric on a substrate and inspects the dielectric film thickness.   The optical laminate inspection apparatus according to claim 11 or 12, wherein the inspection unit measures the reflected light intensity of a specific wavelength to inspect the film thickness.   The optical laminate inspection apparatus according to claim 11 or 12, wherein the inspection unit measures the reflected light intensity of light emitted from a light emitting diode having a specific wavelength to inspect the film thickness.   The spectroscopic means for receiving the reflected light reflected from the optical layered body is provided, and the pigment film thickness is inspected by measuring the reflected light intensity of the spectroscopically separated specific wavelength by the inspection unit. Optical laminate inspection system.   The optical laminate inspection apparatus according to claim 15, wherein the spectroscopic means is a prism.   16. The optical laminate inspection apparatus according to claim 15, wherein the spectroscopic means is a diffraction grating.   An optical filter for selecting the wavelength of incident light is provided, the light selected by the optical filter is incident on the inspection unit, and the reflected light intensity of the optical laminate is measured to inspect the film thickness. The optical laminate inspection apparatus according to 11 or 12.   An optical system that allows light to be incident on the optical laminate from an oblique direction, and the inspection portion measures the pigment film thickness by measuring the reflected light intensity totally reflected by the optical laminate. The optical laminated body inspection apparatus of any one of 11-18.   A control unit for controlling the film thickness by receiving information on the dye film thickness and / or the dielectric film thickness obtained from the inspection result by the optical laminate inspection apparatus according to claim 11. An optical laminate manufacturing apparatus characterized by the above.

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