JP2008064685A - Staining evaluation method, staining evaluation device, and method of manufacturing optical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quantitative staining evaluation method of high reproducibility applicable for various members, and capable of detecting a subtle difference in stain, a staining evaluation device therefor, and a method of manufacturing an optical member. <P>SOLUTION: The problem to be solved is solved by the staining evaluation method of the present invention for evaluating a degree of the stain on a surface of a testing object 3 contacting with an optical waveguide substrate 1, by making light 2 get incident into one end side of the optical waveguide substrate 1 and by detecting the light 2 emitted from the other end side, under the condition where the testing object 3 is brought into close contact with one face out of a pair of cut faces opposed in parallel each other of the optical waveguide substrate 1 in a slab type optical waveguide. The problem to be solved is solved by the staining evaluation device of the present invention having the optical waveguide substrate 1 installed to contact closely with the testing object 3, a light source for making the light 2 get incident into the one end side of the optical waveguide substrate 1, and a detector for detecting the light 2 emitted from the other end side of the optical waveguide substrate 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a contamination evaluation method using a slab type optical waveguide spectroscopy, a contamination evaluation apparatus using this method, and a method for manufacturing an optical member.

  One of the performances required for optical members typified by optical films such as antireflection films for displays and antireflection films for touch panels is antifouling. Specific points that are regarded as important in terms of antifouling properties include fingerprint adhesion and fingerprint wiping properties. In other words, in optical members, dirt due to adhesion of fingerprints or dirt remaining after wiping off fingerprints reduces the optical characteristics that should be originally expressed. Therefore, fingerprint adhesion is low, and even if attached, it can be easily wiped off. Such performance is required.

In addition, as the antifouling property of the optical member needs to be improved, the reproducibility of the evaluation of the antifouling property itself is important. For example, Patent Document 1 describes an artificial fingerprint liquid for quantitatively evaluating the antifouling property, fingerprint adhesion property, or fingerprint removal property of an optical disk surface with good reproducibility.
Japanese Patent No. 3745317 (paragraphs 0006 and 0057)

  As described above, despite the importance of the reproducibility of the evaluation of the antifouling property itself, a method for quantitatively evaluating the antifouling property with good reproducibility has not been proposed. For example, Patent Document 1 aims to improve reproducibility at the stage of fingerprint attachment by developing an artificial fingerprint liquid. In this document, the quantitative evaluation of fingerprint adhesion and fingerprint removal is evaluated by measuring the jitter of a signal recorded on an optical disc. This is an evaluation method that can be realized only with an optical disc, and cannot be widely used for optical members used for other purposes (for example, optical films such as an antireflection film for a display and an antireflection film for a touch panel).

  For this reason, the present situation is that only the visual sensory evaluation is performed for the evaluation of the antifouling property of fingerprint adhesion and fingerprint removal. However, in visual observation, it is difficult to detect and evaluate subtle stain differences, and it cannot be said that reproducibility is necessarily high.

  The present invention has been made in order to solve the above-mentioned problems, and its object is to apply to various members, high reproducibility, and a contamination evaluation method capable of detecting subtle stain differences. Another object of the present invention is to provide a contamination evaluation apparatus and a method for manufacturing an optical member.

  Under the above object, the present inventor can accurately detect the state of dirt adhering to the surface of the optical member or the like by detecting fine information in the vicinity of the optical member surface (on the order of several tens of nm from the surface). I found. As a method for detecting fine information in the vicinity of the optical member surface, the present inventors have found that a slab type optical waveguide spectroscopy can be applied, and completed the present invention.

  That is, the contamination evaluation method of the present invention is the optical waveguide in a state in which the test body is in close contact with one of the pair of facets facing each other in parallel on the optical waveguide substrate of the slab type optical waveguide. The degree of contamination of the surface of the test body in contact with the optical waveguide substrate is evaluated by making light incident on one end side of the substrate and detecting light emitted from the other end side.

  According to the present invention, there is provided a quantitative antifouling method for antifouling that can be applied to test bodies including various optical members, has high reproducibility, and can detect subtle differences in dirt. Is done.

  Moreover, in the contamination evaluation method of this invention, it is preferable that the surface of the said test body is artificially contaminated. According to the present invention, it is possible to evaluate not only the degree of contamination of the specimen but also the antifouling performance (contamination resistance) of the specimen.

  In the contamination evaluation method of the present invention, it is preferable that the artificial contamination is contamination due to fingerprint adhesion. Contamination due to fingerprint attachment makes it possible to evaluate the degree of contamination of the test specimen and the antifouling performance (contamination resistance) of the specimen with particularly good reproducibility.

  In the contamination evaluation method of the present invention, after evaluating the degree of contamination of the surface of the test body, the surface of the test body is washed, and the degree of contamination of the test body is evaluated again, thereby It is preferable to evaluate the degree of recovery from contamination. According to this invention, it becomes possible to evaluate the degree of recovery from contamination of the specimen (the degree of recovery of cleanliness).

  In the contamination evaluation method of the present invention, the intensity is corrected when the intensity of light emitted from the other end changes due to a change in the degree of adhesion of the test specimen on the optical waveguide substrate. It is preferable to evaluate the degree of contamination on the surface of the specimen. According to this invention, it becomes easier to ensure the reproducibility of the evaluation of the degree of contamination.

  The contamination evaluation apparatus according to the present invention includes an optical waveguide substrate in which a specimen is placed in close contact, a light source that enters light on one end side of the optical waveguide substrate, and light emitted from the other end side of the optical waveguide substrate. And a detector for detecting.

  According to the present invention, there is provided a quantitative antifouling device for antifouling that can be applied to test specimens including various optical members, has high reproducibility, and can detect subtle differences in dirt. Is done.

  The contamination evaluation apparatus of the present invention has a correction mechanism that corrects the intensity when the intensity of light emitted from the other end side changes due to a change in the degree of adhesion of the test specimen on the optical waveguide substrate. It is preferable. According to this invention, it becomes easier to ensure the reproducibility of the evaluation of the degree of contamination.

  The method for producing an optical member of the present invention includes the step of obtaining the optical member, and bringing the optical member into close contact with one of a pair of facets facing each other in parallel on the optical waveguide substrate of the slab type optical waveguide. In this state, by injecting light to one end side of the optical waveguide substrate and detecting the light emitted from the other end side, an inspection process for evaluating the surface state of the optical member in contact with the optical waveguide substrate; It is characterized by having.

  According to this invention, since the surface state (contamination degree) of the obtained optical member can be evaluated, even if impurities or contaminants are mixed in the production line, it is easy to cause defects due to these impurities or contaminants. It can be detected.

  Moreover, in the manufacturing method of the optical member of this invention, it is preferable that evaluation of the surface state of the optical member in the said inspection process is evaluation of the contamination degree performed after being artificially contaminated. According to the present invention, there is provided an antifouling quantitative inspection process that can be applied to test bodies including various optical members, has high reproducibility, and can detect subtle differences in dirt. .

  Moreover, in the manufacturing method of the optical member of this invention, it is preferable that the said artificial contamination is contamination by fingerprint adhesion. Contamination due to fingerprint attachment makes it possible to evaluate the degree of contamination of the test specimen and the antifouling performance (contamination resistance) of the specimen with particularly good reproducibility.

  In the optical member manufacturing method of the present invention, in the inspection step, after evaluating the degree of contamination of the surface of the optical member, the surface of the optical member is washed, and the degree of contamination of the optical member is evaluated again. Thus, it is preferable to evaluate the degree of recovery from contamination of the surface. According to this invention, the inspection process which can evaluate the recovery | restoration degree from the contamination of a test body (recovery degree of cleanliness) is provided.

  In the optical member manufacturing method of the present invention, in the inspection step, when the intensity of light emitted from the other end side is changed due to a change in the degree of adhesion of the optical member on the optical waveguide substrate, It is preferable to evaluate the surface state of the surface of the optical member by correcting the intensity. According to this invention, it becomes easier to ensure the reproducibility of the evaluation of the degree of contamination.

  Moreover, in the manufacturing method of the optical member of this invention, it is preferable that the said optical member is an optical film. According to this invention, the effective manufacturing method of the optical film which is a preferable example as an optical member is provided. Examples of the optical film include not only an optical film for a liquid crystal display but also an optical film that can be applied to all displays such as PDP, CRT, and ELD.

  According to the present invention, an antifouling quantitative quantitative contamination evaluation method that can be applied to test specimens including various optical members, has high reproducibility, and can detect subtle differences in dirt. A contamination evaluation apparatus for implementing the evaluation method and an optical member manufacturing method using the evaluation method are provided.

  Next, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

  In the present invention, the light is applied to one end of the optical waveguide substrate in a state where the test body is in close contact with one of the pair of facets facing each other in parallel of the optical waveguide substrate of the slab type optical waveguide. And the degree of contamination of the surface of the test body in contact with the optical waveguide substrate is evaluated by detecting the light emitted from the other end side.

  The present invention is characterized in that a slab type optical waveguide spectroscopic analysis method is used in order to evaluate the degree of contamination on the surface of a specimen. Contaminants on the surface of the test body are generally attached to the surface of the test body with a thickness of 1 μm or less or a penetration depth, except for coarse dust that can be easily confirmed by visual inspection. Therefore, in order to accurately detect the state of contamination on the surface of the test specimen, it is desirable to detect fine information in the vicinity of the specimen surface (on the order of several tens of nanometers) with high precision. On the other hand, in the slab type optical waveguide spectroscopic analysis method, the evanescent wave that penetrates the interface of the contact object (test specimen) that is in close contact with the optical waveguide substrate from the irradiation light that travels in the optical waveguide substrate is dispersed, and the optical properties are absorbed. This is a nanoanalytical instrument for examining the state of the interface between the waveguide substrate and the contact object. Therefore, by using the slab type optical waveguide spectroscopic analysis method, it becomes possible to accurately detect information on contaminants existing at the interface between the specimen and the optical waveguide substrate.

  Hereinafter, specific examples of the contamination evaluation method and the contamination evaluation apparatus of the present invention will be described with reference to the drawings. First, the contamination evaluation apparatus will be described.

[Contamination evaluation equipment]
The contamination evaluation apparatus includes an optical waveguide substrate in which a specimen is placed in close contact, a light source that enters light on one end side of the optical waveguide substrate, and a detector that detects light emitted from the other end side of the optical waveguide substrate And having. With respect to the contamination evaluation apparatus, first, the measurement principle will be described, and then the specific configuration of the apparatus will be described.

FIG. 1 shows the principle of slab type optical waveguide spectroscopy. As the slab type optical waveguide, an optical waveguide substrate 1 made of a transparent material such as quartz is usually used. As shown in FIG. 1, the optical waveguide substrate 1 has a pair of facets (two upper and lower faces in FIG. 1) facing each other in parallel with each other, and the parallel facets are inclined to cross each other and are not parallel to each other. It has a slab shape composed of facets on opposite ends on opposite sides. When light 2 enters from a facet on one end side of the optical waveguide substrate 1 (the inclined surface on the left side in FIG. 1), both facets (on the upper side in FIG. The first surface and the lower surface travel with total reflection, and exit from the facet at the other end (the inclined surface on the right side in FIG. 1). At this time, when the test body 3 is brought into close contact with one of the parallel facets on the optical waveguide substrate, the surface wave of the light 2 that travels by being totally reflected in the optical waveguide substrate 1 is generated. Slightly penetrates (distance about the wavelength of light). This surface wave is referred to as an evanescent wave 4 and penetrates into the specimen 3 while being attenuated exponentially as described in FIG. The penetration depth (dp) at this time is expressed by the following equation. In the following formula, λ is the incident wave wavelength, θ is the incident angle, n ₁ is the refractive index of the waveguide substrate, and n ₂ is the refractive index of the test body or the environment around the test body.

  In this slab type optical waveguide, the penetration depth (dp) is very shallow, and information on only molecules existing within 1 μm from the surface of the optical waveguide substrate 1 is selectively and nondestructively analyzed by adjustment. Can do. Further, by using the thinner optical waveguide substrate 1, by increasing the number of reflections, it is possible to increase the accumulated amount of evanescent waves that are exuded, and to measure with higher sensitivity. Examples of a spectrum measuring apparatus using such a slab type optical waveguide include measuring apparatuses disclosed in Japanese Patent Laid-Open Nos. 8-75639 and 2001-108611, and more specifically, a system. An SIS-50 type apparatus manufactured by Instruments can be mentioned.

  FIG. 2 is a schematic configuration diagram illustrating an example of a spectrum measuring apparatus using a slab type optical waveguide that can be used as a contamination evaluation apparatus. The contamination evaluation apparatus in FIG. 2 includes a slab type optical waveguide 13 having an optical waveguide substrate on which a test body is placed in close contact, a light source 10 that makes light incident on one end side of the optical waveguide substrate, and the other end of the optical waveguide substrate. And a spectroscope 41 which is a detector for detecting light emitted from the side. More specifically, the contamination evaluation apparatus in FIG. 2 includes the light source 10, the incident light side optical fiber 31, lenses 33 and 34, the light chopper 30, the incident light side lens 11, the incident light side prism 12, and the slab type optical waveguide 13. , Position control mechanism 16, outgoing light side prism 14, outgoing light side lens 15, optical fiber 32, spectrometer 41, photomultiplier tube 43, amplifier 44, and computer 42.

  The light source 10 is used to make light incident on one end side of the optical waveguide substrate. As the light source 10, a light source that emits light having an arbitrary wavelength range from far ultraviolet to far infrared is used. For example, an Xe lamp is used. The light chopper 30 turns the light from the light source 10 into intermittent light having a constant period, and is provided between the light source 10 and the incident light side optical fiber 31.

  The slab type optical waveguide 13 has an optical waveguide substrate on which the test body is placed in close contact, and is installed in the sample measuring section. The sample measuring unit includes an incident light side lens 11, an outgoing light side lens 15, an incident light side prism 12, an outgoing light side prism 14, a slab type optical waveguide 13, and a position control mechanism 16. The incident light side lens 11 is provided at the distal end on the exit side of the incident light side optical fiber 31, and the outgoing light side lens 15 is provided at the distal end on the entrance side of the outgoing light side optical fiber 32. Note that, as described in JP 2001-108611 A, an optical coupling method that does not use a prism can be applied.

  3 and 4 are a schematic plan view and a cross-sectional view showing an enlarged peripheral portion of the slab type optical waveguide. As can be seen from FIGS. 3 and 4, the incident light side prism 12 and the outgoing light side prism 14 are arranged on the slab type optical waveguide 13 composed of the substrate 51 and the optical waveguide substrate 52.

  The incident light side prism 12 and the outgoing light side prism 14 are disposed on the slab type optical waveguide 13. Each of the prisms 12 and 14 may be called a contaminated or possibly contaminated test body 3a and an uncontaminated test body 3b (hereinafter simply referred to as a test body 3a or a test body 3b). ) To be measurable without re-attaching the prism. The slab type optical waveguide 13 includes a substrate 51 for supporting the optical waveguide substrate 52 and an optical waveguide substrate 52. In one side portion of the slab type optical waveguide 13, the strip-shaped test body 3 a is in close contact with the optical waveguide substrate 52 such that the contaminated or possibly contaminated surface is in contact with the optical waveguide substrate 52. A test specimen 3b serving as a reference is in close contact with the opposite side, that is, a portion adjacent to the test specimen 3a. In the cross-sectional view of FIG. 4, the test body 3b is not shown, but this is because the figure shows a cross section crossing the test body 3a. The test bodies 3a and 3b are not limited as long as it is necessary to evaluate the degree of surface contamination. Examples of such test bodies 3a and 3b include optical members typified by optical films such as antireflection films for displays and antireflection films for touch panels, and optical disks such as CD, DVD, and blue laser compatible disks. Can do. Since the test bodies 3a and 3b need to be sized so that they can be placed on the optical waveguide substrate 52 as shown in FIG. 3, the optical film, the optical disk, etc. are cut out to have a predetermined size.

  On the other hand, the detection unit includes a spectroscope 41, a photomultiplier tube 43, an amplifier 44, and a computer 42 as shown in FIG.

  Next, the measurement in the contamination evaluation apparatus shown in FIGS. The white light emitted from the light source 10 is made into intermittent light with a constant period by the light chopper 30 and then introduced into the incident light side optical fiber 31. The intermittent light introduced into the incident light side optical fiber 31 passes through the incident light side optical fiber 31 and is collected by the incident light side lens 11 provided at the incident side tip, and is introduced into the incident light side prism 12 at an appropriate angle. Is done. The intermittent light collected by the incident light side lens 11 is introduced into the incident light side prism 12, then enters the optical waveguide substrate 52 from one end side of the slab type optical waveguide 13, and enters the optical waveguide substrate 52. The incident intermittent light repeats total reflection between a pair of facets facing in parallel in the optical waveguide substrate 52 (between the front and back surfaces of the optical waveguide substrate 52), and then is emitted from the other end side of the optical waveguide substrate 52. The light is introduced into the outgoing light side prism 14. The intermittent light introduced into the outgoing light side prism 14 is taken out by the outgoing light side lens 15 provided at the light incident side tip of the outgoing light side optical fiber 32 and the outgoing light side optical fiber 32 serves as a detector. 41. The intermittent light dispersed by the spectroscope 41 is sent to the computer 42 through the photomultiplier tube 43 and the amplifier 44, and is subjected to arithmetic processing, whereby a spectral absorption spectrum is obtained. Then, based on the spectrum obtained from the uncontaminated test body 3b (mainly the spectrum derived from the material in the vicinity of the surface of the test body 3b), from the test body 3a that is contaminated or possibly contaminated. The degree of contamination of the surface of the specimen 3a can be quantitatively detected from the integrated value of the absorption intensity of the characteristic peak derived from the contamination of the surface of the specimen 3a that appears in the obtained spectrum from 350 nm to 400 nm. Here, if a calibration curve is obtained in advance for the relationship between the absorption intensity and the amount of adhering contaminants, it becomes easier to perform more accurate analysis. In addition, in the case of an application in which it is not necessary to specify and determine the amount of contaminants and only detect the presence or absence of contamination, the output light is directly supplied from the output light side optical fiber 32 to the photomultiplier tube 43 without providing a spectrometer. You can send it.

  One of the advantages of using a characteristic peak derived from contamination on the surface of the specimen 3a appearing at 350 nm to 400 nm is that qualitative analysis of the contaminant is possible. For example, when the pollutant is derived from human sebum, a peak derived from triglyceride is observed, and when the pollutant is derived from cosmetics such as foundation, a peak derived from talc, mica, titania, etc. Is observed.

  By the way, one of the important points in the above measurement is to ensure the close contact between the optical waveguide substrate 52 and the test bodies 3a and 3b. Therefore, although not shown in FIGS. 3 and 4, it is desirable that the test bodies 3 a and 3 b are brought into close contact with the optical waveguide substrate 52 and then completely crimped and fixed by a crimping jig. It is important to ensure the close contact between the optical waveguide substrate 52 and the test bodies 3a and 3b for the following two reasons.

  The first reason is derived from the characteristic of the slab type optical waveguide spectroscopic analysis method in which detailed information on the interface between the optical waveguide substrate 52 and the test bodies 3a and 3b is detected using an evanescent wave. . More specifically, when the state of close contact between the optical waveguide substrate 52 and the test bodies 3a and 3b changes at each measurement, the state of the interface formed between the optical waveguide substrate 52 and the test bodies 3a and 3b, and The intensity of the evanescent wave that permeates into the test body also changes with each measurement, and the evaluation result of the degree of contamination may vary, and the reproducibility may not be obtained. For this reason, it is important to ensure adhesion between the optical waveguide substrate 52 and the test bodies 3a and 3b.

  The second reason is that the degree of contamination on the surface of the specimen in the contamination evaluation method and the contamination evaluation apparatus is obtained from the integral value of the spectrum peak. More specifically, when the adhesion degree between the optical waveguide substrate 52 and the test bodies 3a and 3b varies for each measurement of the contaminated test body 3a, the peak intensity changes for each measurement. The integrated value may fluctuate. Also in this case, since there is a possibility that a problem occurs in reproducibility, it is important to ensure the close contact between the optical waveguide substrate 52 and the test bodies 3a and 3b.

  Therefore, it is preferable that the degree of adhesion between the optical waveguide substrate 52 and the test bodies 3a and 3b is always constant for each measurement using the above-described crimping jig. However, even if the shape of the crimping jig is devised so that the degree of adhesion is always constant for each measurement, depending on how the measurer uses the crimping jig, the optical waveguide substrate 52 The possibility that the degree of close contact with the test bodies 3a and 3b varies may not be completely eliminated. Even in such a case, in order to obtain a highly reproducible evaluation result, the intensity of light emitted from the other end side of the optical waveguide substrate 52 is changed by the change in the degree of adhesion of the test bodies 3a and 3b on the optical waveguide substrate 52. It is preferable to provide a correction mechanism for correcting this intensity in the contamination evaluation apparatus when it changes. As the correction mechanism, for example, a software that performs predetermined correction processing in the computer 42 can be cited. More specifically, a variation in the intensity of the emitted light accompanying a variation in the degree of close contact that may occur is stored in a memory in the computer 42, and the raw data obtained in the measurement and the data in the database are The computer 42 may be installed with software that performs a correction process on the raw data. By providing such a correction mechanism, even when the intensity of light emitted from the other end side of the optical waveguide substrate 52 is changed due to a change in the degree of adhesion of the test bodies 3a and 3b on the optical waveguide substrate 52, Processing is performed to correct the change in the intensity of light and to ensure the reproducibility of the evaluation result of the degree of contamination on the surface of the specimen 3a.

[Contamination evaluation method]
In the contamination evaluation method of the present invention, a test specimen is in close contact with one surface of a pair of facets facing each other in parallel of an optical waveguide substrate of a slab type optical waveguide. By making light incident on one end side and detecting light emitted from the other end side, the degree of contamination of the surface of the test body in contact with the optical waveguide substrate is evaluated. Since there is a part already mentioned in the description of the pollution evaluation apparatus, the following description is applied to the evaluation method of contamination according to the present invention for avoiding duplication. Will be described.

  As an applied evaluation method, the surface of the specimen is artificially contaminated, and it is preferable to employ a method for evaluating the degree of contamination of the surface. Such an applied evaluation makes it possible to evaluate not only the degree of contamination of the specimen but also the antifouling performance (contamination resistance) of the specimen.

  Appearing at 350 nm to 400 nm in the spectrum obtained from the contaminated specimen, with reference to the reference (uncontaminated specimen), after various types of specimens are subjected to artificial contamination, respectively. By measuring the integrated value of the absorption intensity of a characteristic peak derived from contamination on the specimen surface and comparing the magnitude of the integral values obtained for each specimen, it is easy to get dirty and hard to get dirty (antifouling performance) ) Will be able to perform precise relative evaluation. As a result, for example, it is possible to obtain an effective evaluation means in the development of a specimen (for example, an optical member) that is difficult to get dirty.

  When evaluating the antifouling performance, it is important to perform artificial contamination with good reproducibility. This is because, when comparing the antifouling performance among a plurality of test specimens, if the degree of objective contamination differs for each test specimen, it is difficult to perform accurate evaluation. Specifically, it is preferable that the artificial contamination is contamination due to fingerprint adhesion. Furthermore, in order to suppress the variation between evaluations, the artificial fingerprint liquid is pressed against the test body with a constant load rather than the method of attaching a fingerprint to the test body using a human finger, and the artificial fingerprint liquid is applied to the test body. It is preferable to adopt a method of adhering to the substrate. This is because when human fingers are used, the sebum secreted depending on the physical condition may not be constant.

  As the artificial fingerprint liquid, for example, those introduced in Japanese Patent No. 3745317 can be used. Specifically, a pseudo fingerprint liquid containing triolein and fine particles can be mentioned. Then, using a transfer member (for example, a cylindrical indenter) having a predetermined weight, the artificial fingerprint liquid is pressed and adhered to the surface of the test body.

  As a further applied evaluation of the present invention, it is preferable to evaluate the degree of contamination on the surface of the test specimen, then clean the surface of the specimen and evaluate the degree of contamination of the specimen again. This makes it possible to evaluate the degree of recovery from surface contamination (the degree of cleanliness recovery).

  After washing, the integrated value of the absorption intensity of the characteristic peak derived from contamination of the specimen surface appearing at 350 nm to 400 nm in the spectrum obtained from the specimen decreases, and the specimen closer to the reference recovers cleanliness. Since it can be said that the degree is high, this applied evaluation also makes it possible to evaluate the degree of recovery from contamination of the specimen (degree of recovery of cleanliness). If only the degree of contamination on the surface of the test body is evaluated, the accuracy is low, but a certain degree of evaluation is possible even by visual evaluation with human eyes. However, since the cleaned specimen is usually indistinguishable from the uncontaminated specimen, it is difficult to visually evaluate the degree of recovery from the contamination of the specimen (degree of restoration of cleanliness). On the other hand, since the evaluation method of the present invention can accurately detect information on the interface formed between the optical waveguide substrate and the test body by the evanescent wave, the degree of recovery from contamination of the test body (degree of recovery of cleanliness) There is an advantage that it is easy to perform such delicate evaluation with high accuracy and reproducibility.

  In the present invention, there is also an advantage that the contamination test and the cleanliness recovery degree test can be performed separately. An optical member, which is an example of a test body, is preferably required to be resistant to dirt and wipe off dirt cleanly (high degree of recovery of cleanliness). Even those with a high degree of recovery may be suitable for actual use depending on the application. In developing such an optical member that “stains cleanly even if it is easily dirty (high degree of recovery of cleanliness)”, the contamination evaluation method of the present invention can be preferably employed.

  There is no particular limitation on the specific method of cleaning performed when evaluating the degree of recovery from contamination of the test specimen (degree of recovery of cleanliness). However, it is important to clean the surface of the specimen with good reproducibility. This is because, when comparing the degree of recovery of cleanliness among a plurality of test specimens, if the degree of objective cleaning differs for each specimen, accurate evaluation is difficult to perform.

  When the specimen is an optical member typified by an optical film such as an antireflection film for a display or an antireflection film for a touch panel, in general, the surface of the specimen is cleaned with a wipe item such as Kimwipe. A method of wiping off dirt (contaminated site) with a constant force and angle is adopted. As long as the force and angle increase / decrease can be made constant for each cleaning, it may be performed manually, but an example of a method for mechanically cleaning is a method using a wear resistance tester. In addition, the antireflection film of the present invention means both an antireflection film due to optical interference and an antireflection film due to imparting antiglare property due to the uneven shape.

  When performing mechanical cleaning with an abrasion resistance tester, wipe off items such as kimwipe wound around the indenter part of an abrasion resistance tester (for example, abrasion resistance tester TYPE F manufactured by Haydon Co., Ltd.) with a constant load. After pressing against the contaminated surface, the indenter part may be reciprocated to wipe off the dirt on the specimen. By controlling the wiping items and the weight applied when wiping, cleaning with high reproducibility is facilitated.

  About the test body cleaned as described above, if the contamination property is evaluated again with the above-described contamination evaluation apparatus using the slab type optical waveguide having the optical waveguide substrate, the degree of recovery from the contamination of the specimen ( The degree of cleanliness recovery) can be evaluated quantitatively and with good reproducibility.

[Method for producing optical member]
The method for producing an optical member of the present invention includes the step of obtaining the optical member, and bringing the optical member into close contact with one of a pair of facets facing each other in parallel on the optical waveguide substrate of the slab type optical waveguide. And inspecting the surface state of the optical member in contact with the optical waveguide substrate by detecting the light emitted from one end side of the optical waveguide substrate and detecting the light emitted from the other end side. As a result, the degree of contamination on the surface of the test specimen, the contamination resistance, and the degree of recovery from contamination (the degree of recovery of cleanliness) can be evaluated during the manufacturing process of the optical member. For this reason, for example, if the inspection process is performed by the contamination evaluation method at the final stage of the manufacturing process of the optical member, the quality control or performance confirmation of the optical member can be performed.

  Examples of the optical member include an optical member typified by an optical film such as an antireflection film for display and an antireflection film for touch panel. In addition, even if it is other than an optical member, as described as an example of the said test body, if it is necessary to evaluate the degree of surface contamination, it is applicable to the said manufacturing method.

  Representative examples of the optical member include an optical film such as an antireflection film for display and an antireflection film for touch panel as described above. There are various modes of optical films. A typical example is an antireflection laminate (Anti Reflection product) having an antireflection performance and having a layer structure of a light-transmitting substrate / hard coat layer / high refractive index layer / low refractive index layer, and the outermost surface. And an anti-glare optical laminate (Anti Glare product) having a layer structure of a light-transmitting substrate / anti-glare layer (having a hard coat function). The antiglare layer may be a single layer or a multilayer.

(Step of obtaining optical member)
As a process for obtaining the optical member, a process for obtaining the optical laminate will be described below as an example. The step of obtaining an optical laminate is usually a step of providing an antiglare layer having irregularities on a light-transmitting substrate, and a composition for forming a surface adjustment layer containing a resin binder on the antiglare layer obtained by this step Forming a surface adjustment layer with an object. The surface adjustment layer is a layer for adjusting the uneven shape of the antiglare layer having the unevenness to a more preferable shape. In particular, in an antiglare layer, black gradation is poor (because light is scattered on an uneven surface, so that black appears grayish), and a surface adjustment layer is formed. Thus, this problem can be improved satisfactorily. Here, the physical property that black gradation is improved and black appears to be glossy black is called glossy blackness.

  As the light-transmitting substrate, a substrate having smoothness and heat resistance and excellent in mechanical strength is preferable. Examples of the material forming the light-transmitting substrate include polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), cellulose (cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, etc.), acrylic (polymethyl methacrylate, etc.) ), Polyether sulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polycarbonate, and other thermoplastic resins. Further, there is an amorphous olefin polymer (Cyclo-Olefin-Polymer: COP) film having an alicyclic structure. This is a substrate on which a norbornene polymer, a monocyclic olefin polymer, a cyclic conjugated diene polymer, a vinyl alicyclic hydrocarbon polymer resin, or the like is used. For example, ZEONEX and ZEONOR (Norbornene resin) manufactured by Nippon Zeon Co., Ltd., Sumilite FS-1700 (Sumilite is a registered trademark) manufactured by Sumitomo Bakelite Co., Ltd., Arton (modified norbornene resin) manufactured by JSR Corporation, Apel (cyclic olefin copolymer, Apel is a registered trademark) manufactured by Mitsui Chemicals, Inc. Topas manufactured by Ticona (a cyclic olefin copolymer, Topas is a registered trademark), Optretz OZ- manufactured by Hitachi Chemical Co., Ltd. 1000 series (alicyclic acrylic resin) etc. are mentioned. Further, the FV series (low birefringence, low photoelastic modulus film) manufactured by Asahi Kasei Chemicals Corporation is also preferable as an alternative base material for triacetylcellulose. The thickness of the light-transmitting substrate is usually 20 μm or more and 300 μm or less, but depending on the substrate, it may be 300 μm or more and 5000 μm or less.

  The method for forming the antiglare layer on the light-transmitting substrate is not particularly limited. However, the curable resin and the concavo-convex forming fine particles (the fine particles for forming the concavo-convex shape of the antiglare layer, hereinafter, the fine particles, and It is preferable to carry out by a method of forming an antiglare layer having a concavo-convex shape using a composition for forming an antiglare layer containing Several kinds of fine particles having different types, sizes, and shapes can be appropriately selected and used. Generally, plastic beads such as polystyrene beads, melamine beads, acrylic (polymethyl methacrylate, etc.) beads, acrylic-styrene beads, benzoguanamine-formaldehyde beads, polycarbonate beads, polyethylene beads, etc. having a particle size of 1 μm to 20 μm Silica beads are used. Several kinds of beads can be used at the same time. For example, plastic beads such as acrylic beads having a particle diameter of 1 μm or more and 20 μm or less and amorphous silica beads having an average particle diameter of 1 to 3 μm can be used in combination.

  The antiglare layer can be formed of a composition for forming an antiglare layer containing the fine particles and the curable resin. The curable resin is preferably a transparent one, for example, an ionizing radiation curable resin that is a resin curable by ultraviolet rays or an electron beam, a mixture of an ionizing radiation curable resin and a thermoplastic resin, or a thermosetting resin. Can be mentioned. More preferred is an ionizing radiation curable resin. As the ionizing radiation curable resin, a resin exemplified as a resin that can be used as a resin binder in the surface adjustment layer described later can be used.

  The antiglare layer comprises fine particles and a resin in an appropriate solvent, for example, alcohols such as isopropyl alcohol, methanol, and ethanol; ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone; methyl acetate and ethyl acetate. An ester such as butyl acetate; a halogenated hydrocarbon; an aromatic hydrocarbon such as toluene and xylene; or a composition for forming an antiglare layer obtained by mixing the mixture with a mixture thereof. Can be formed.

  Moreover, it is preferable to add leveling agents, such as a fluorine type or a silicone type, to the said composition for anti-glare layer formation. The composition for forming an antiglare layer to which a leveling agent is added can improve the coating suitability and can impart the effect of scratch resistance.

  Examples of the method for applying the antiglare layer forming composition to the light-transmitting substrate include application methods such as a roll coating method, a Miya bar coating method, and a gravure coating method. After application of the composition for forming an antiglare layer, drying and ultraviolet curing are performed as necessary. Specific examples of the ultraviolet light source include ultrahigh pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arc lamps, black light fluorescent lamps, and metal halide lamp lamps. As the wavelength of the ultraviolet light, a wavelength range of 190 to 380 nm can be used. Specific examples of the electron beam source include various electron beam accelerators such as a cockcroft-wald type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. The resin is cured, fine particles in the resin are fixed, and a desired uneven shape is formed on the outermost surface of the antiglare layer.

  Next, a surface adjustment layer is formed with the composition for surface adjustment layer formation containing a resin binder on the glare-proof layer obtained as mentioned above.

  The surface adjustment layer contains a resin binder. Although it does not specifically limit as said resin binder, A transparent thing is preferable, For example, ionizing radiation curable resin which is resin hardened | cured by an ultraviolet-ray or an electron beam can be mentioned. In the present specification, “resin” is a concept including resin components such as monomers and oligomers.

  Examples of the ionizing radiation curable resin include compounds having one or more unsaturated bonds such as a compound having a radical polymerizable functional group such as a (meth) acrylate group. Examples of the compound having one unsaturated bond include ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like. Examples of the compound having two or more unsaturated bonds include trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri ( Reaction products such as (meth) allyllate and polyfunctional compounds such as (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate And poly (meth) acrylate ester of polyhydric alcohol). In the present specification, “(meth) acrylate” refers to methacrylate and acrylate.

  In addition to the above compounds, relatively low molecular weight polyester resins having unsaturated double bonds, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc. It can be used as an ionizing radiation curable resin.

  When the ionizing radiation curable resin is used as an ultraviolet curable resin, it is preferable to add a photopolymerization initiator or a photopolymerization accelerator to the surface adjustment layer forming composition. As a photopolymerization initiator, in the case of a resin system having a radical polymerizable unsaturated group, it is commercially available as acetophenones (for example, trade name Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure is a registered trademark)). 1-hydroxy-cyclohexyl-phenyl-ketone), benzophenones, thioxanthones, propiophenones, benzyls, acylphosphine oxides, benzoin, benzoin methyl ether and the like can be used alone or in combination. In the case of a resin system having a cationic polymerizable functional group, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metallocene compound, a benzoin sulfonic acid ester or the like is used alone or as a mixture as a photopolymerization initiator. be able to. The addition amount of the photopolymerization initiator is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the ionizing radiation curable resin.

  As described above, the surface adjustment layer is effective for improving the glossy blackness. On the other hand, depending on the surface adjustment layer, the glossy black feeling is improved, but the antiglare property may be deteriorated. Therefore, for the purpose of improving the antiglare property without losing the glossy blackness, a fluidity adjusting agent may be contained. As the fluidity adjusting agent, organic fine particles and inorganic fine particles are generally used. As the fluidity adjuster, colloidal silica, ATO, ultrafine zirconia particles, ultrafine antimony oxide, or the like is preferably used, and colloidal silica is particularly preferable. The preferable size is about 1 to 70 nm. In the present invention, “colloidal silica” means a colloidal solution in which colloidal silica particles are dispersed in water or an organic solvent. The particle size (diameter) of the colloidal silica is preferably that of ultrafine particles of 1 to 70 nm, for example. In addition, the particle diameter of colloidal silica in this specification is an average particle diameter according to the BET method (a surface area is measured by the BET method, and the average particle diameter is calculated by converting the particles to be true spheres).

  In addition to the functions described above, the surface adjustment layer may have a function of imparting antistatic properties, refractive index adjustment, high hardness, antifouling properties, and the like. In this case, the said surface adjustment layer can be formed with the composition for surface adjustment layer formation containing another additive (for example, antifouling agent) as needed.

  Although the formation method of the said surface adjustment layer is not specifically limited, For example, the surface obtained by mixing the above-mentioned organic fine particle or inorganic fine particle, resin binder (including resin components, such as a monomer and an oligomer), a solvent, and arbitrary components It can form by apply | coating the composition for adjustment layer formation on a glare-proof layer. Solvents include alcohols such as isopropyl alcohol, methanol and ethanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as methyl acetate, ethyl acetate and butyl acetate; halogenated hydrocarbons; toluene, xylene and the like Aromatic hydrocarbons; or a mixture thereof, preferably ketones and esters.

  The composition for forming a surface adjustment layer may further contain a leveling agent such as fluorine or silicone. The composition for forming a surface adjustment layer to which a leveling agent is added has a function of improving the coated surface and imparting an effect of scratch resistance.

  The composition for forming a surface adjustment layer can be applied by a known coating method such as a Miya bar coating method, a roll coating method, or a gravure coating method. After application of the composition for forming a surface adjustment layer, drying and curing are performed as necessary. In the formation of the surface adjustment layer, it is preferable to use an ultraviolet curable resin as the resin binder and perform curing with ultraviolet rays. When curing by ultraviolet rays, it is preferable to use ultraviolet rays having a wavelength range of 190 to 380 nm. Curing with ultraviolet rays can be performed, for example, with a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, or the like. Specific examples of the electron beam source include various electron beam accelerators such as a cockcroft-wald type, a bandegraft type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type.

(Inspection process)
The optical film exemplified by the optical laminate obtained as described above is inspected as follows. That is, light is incident on one end side of the optical waveguide substrate in a state where the optical film is in close contact with one of the pair of facets facing each other in parallel of the optical waveguide substrate of the slab type optical waveguide, By detecting the light emitted from the other end, the surface state of the optical film in contact with the optical waveguide substrate is evaluated. Such evaluation is usually performed by collecting an optical film immediately after production from the production line at a predetermined frequency and separately evaluating the collected optical film (test body). If the intensity of light emitted from the other end of the optical waveguide substrate changes due to variations in the degree of adhesion of the optical film on the optical waveguide substrate in each measurement, depending on how the crimping jig is used, this strength As for the point that it is preferable to evaluate the surface condition of the surface of the optical film, the principle, method, apparatus, etc. described in the above-mentioned contamination evaluation method and the contamination evaluation apparatus can be used. Description of is omitted. By performing such an evaluation, the surface state (contamination level) of the obtained optical film can be evaluated, so that even if impurities or contaminants enter the production line, problems due to these impurities or contaminants occur. Can be easily detected.

  In the inspection step, the evaluation of the surface state of the optical film may be an evaluation of the degree of contamination performed after being artificially contaminated. By such an applied evaluation method, the quality of the antifouling performance of the optical film can be confirmed. In particular, when the optical film immediately after production is sampled from the production line at a predetermined frequency and this collected optical film (test body) is separately evaluated, it is preferable to perform the above-described applied evaluation. For the details of the evaluation method, such as the fact that the artificial contamination is preferably fingerprint contamination, the principle, method, device, etc. described in the contamination evaluation method and the contamination evaluation device can be used. The description here is omitted.

  In the inspection step, after evaluating the degree of contamination of the surface of the optical film, the surface of the optical film is washed and the degree of contamination of the optical film is evaluated again to evaluate the degree of recovery from the contamination of the surface. May be. By such further applied evaluation, the quality of the recovery performance of the cleanliness of the optical film can be confirmed. In particular, when the optical film immediately after production is collected from the production line at a predetermined frequency and this collected optical film (test body) is separately evaluated, it is preferable to perform the further applied evaluation described above. For details of the evaluation method, the principle, method, device and the like described in the above-described contamination evaluation method and contamination evaluation apparatus can be used, and thus description thereof is omitted here.

  The inspection process described above can be carried out after the process of obtaining the optical member itself is completely completed as illustrated above, but at an appropriate stage in the process of obtaining the optical member (a semi-finished product in the middle of the manufacturing process). However, it can also be done after the need or significance of assessing contamination has occurred. Also, when the inspection process is performed after the process of obtaining the optical member itself is completed, the time interval between the two processes is arbitrary (1 second, 1 day, 1 month, etc.) and may be set as appropriate.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

(Preparation of optical laminate and specimen)
First, the following materials were sufficiently mixed to prepare a composition having a solid content of 40.5%. This composition was filtered through a polypropylene filter having a pore size of 30 μm to prepare a composition for forming an antiglare layer.

UV curable resin;
Pentaerythritol triacrylate (PET) (refractive index 1.51)
2.20 parts by mass isocyanuric acid-modified diacrylate M215 (manufactured by Nippon Kayaku Co., Ltd., refractive index 1.51)
1.21 parts by weight polymethyl methacrylate (molecular weight 75,000) 0.34 parts by weight photocuring initiator;
Irgacure 184 (Ciba Specialty Chemicals Co., Ltd.)
0.22 parts by mass Irgacure 907 (manufactured by Ciba Specialty Chemicals)
0.04 parts by mass of translucent first fine particles;
Monodispersed acrylic beads (particle size 9.5 μm, refractive index 1.535)
0.68 parts by mass of translucent second fine particles;
Amorphous silica ink (average particle size 1.5μm, solid content 60%, silica component 15% of total solid)
0.64 parts by weight leveling agent;
Silicone leveling agent
0.02 parts by weight solvent;
Toluene 5.88 parts by mass Cyclohexanone 1.55 parts by mass

  Next, the following materials were sufficiently mixed to prepare a composition. The composition was filtered through a polypropylene filter having a pore diameter of 10 μm to prepare a composition for a surface adjustment layer having a solid content of 40.5%.

UV curable resin;
Multifunctional urethane acrylate UV1700B (refractive index 1.51 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
31.1 parts by weight Aronix M315 (trade name, triacrylate of ethylene oxide 3 mol adduct of isocyanuric acid manufactured by Toagosei Co., Ltd.)
10.4 parts by weight photocuring initiator;
Irgacure 184 (Ciba Specialty Chemicals Co., Ltd.)
1.49 parts by mass Irgacure 907 (Ciba Specialty Chemicals Co., Ltd.)
0.41 parts by mass antifouling agent;
UT-3971 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
2.07 parts by weight solvent;
Toluene 525.18 parts by mass Cyclohexanone 60.28 parts by mass

  A biaxially stretched polyethylene terephthalate film (trade name “A4300”, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm is used as a transparent substrate, and the composition for forming an antiglare layer is coated on the film with a winding rod (miyabar) for coating # 8 was applied and dried in an oven at 70 ° C. for 1 minute to evaporate the solvent. Then, the coating was cured by irradiating ultraviolet rays so that the irradiation dose was 30 mJ to form an antiglare layer. .

  Further, the composition for the surface adjustment layer was applied on the antiglare layer by using a winding rod (miyabar) # 10 for coating, and heated and dried in an oven at 70 ° C. for 1 minute to evaporate the solvent. Thereafter, under a nitrogen purge (oxygen concentration of 200 ppm or less), the coating was cured by irradiating with ultraviolet rays so that the irradiation dose was 100 mJ, and the surface adjustment layer was laminated to obtain an optical laminate (prevention on the substrate). Total thickness of glare layer: about 12.5 μm).

  From the film-like optical laminate obtained as described above, a film having a size of 0.5 cm × 2 cm was cut out as a test specimen for evaluating contamination.

[Example 1]
(Contamination of specimen (fingerprint adhesion))
A pseudo-fingerprint liquid (artificial fingerprint liquid) containing triolein and fine particles is pressed onto the specimen by an indenter with a load of 500 g (contact surface is a circle with a diameter of 1.2 mmφ), and the artificial fingerprint liquid is applied to the specimen surface. Attached. By this attachment method, it is possible to attach the fingerprint quantitatively to the test body. In this experiment, 0.04 mg of artificial fingerprint per 1 mm ² was attached under the above attachment conditions.

(Contamination assessment test)
The test specimen used as a reference and the test specimen subjected to the fingerprint adhesion treatment were adhered to a quartz waveguide substrate manufactured by System Instruments Co., Ltd. with a roller so as not to cause wrinkles or sagging. At this time, the test piece subjected to the fingerprint adhesion treatment was brought into close contact with the fingerprint adhesion surface and the optical waveguide substrate. Then, the crimping jig was adhered until the crimping scale on the crimping jig reached 100, and the optical waveguide substrate and the test specimen were crimped and fixed. With respect to this specimen, the spectral absorption spectrum of the evanescent wave was measured with a SIS-50 type optical waveguide spectrophotometer manufactured by System Instruments Co., Ltd.

  The surface of the specimen appearing at 350 to 400 nm of the spectrum obtained from the specimen subjected to the fingerprint attachment process, based on the spectrum obtained from the reference specimen (mainly derived from the optical material coated on the film). The amount of fingerprint adhering was determined from the integrated absorption intensity of the peak derived from the fingerprint adhering to. At this time, a calibration curve was obtained in advance with respect to the relationship between the absorption intensity and the amount of adhering contaminants when the compression scale was 100, and the amount of fingerprint adhesion was obtained using this calibration curve. As a result, in the case of the test body to which fingerprint adhesion (contamination) was applied, a fingerprint adhesion amount of 0.05 mg was confirmed.

  Specifically, the calibration curve was created by the following method. Prepare specimens in which contaminants are deposited in advance by changing the film thickness (attachment amount) by bar coating with a Miya bar, and then determine the absorption strength of these specimens using the optical waveguide spectrophotometer described above. It was. Table 1 shows the measurement results of the adhesion amount and the relative absorption intensity. A calibration curve was prepared from the amount of adhesion and the value of relative absorption intensity. Next, as a result of measuring the absorption intensity of the test specimen to which fingerprint adhesion (contamination) was applied in the same manner, the relative absorption intensity was 3.0, and a fingerprint adhesion amount of 0.05 mg was confirmed from the calibration curve.

  By the way, since the degree of adhesion between the optical waveguide substrate and the test body varies depending on the pressure (crimping scale) of the crimping jig, the absorption strength varies. Therefore, in order to confirm whether or not measurement data consistent with the case of the crimping scale 100 can be obtained even when the crimping scale is loosened to 50 (when the adhesion between the optical waveguide substrate and the test body is lowered). The following experiment was conducted.

  The optical waveguide substrate and the test piece to which the above-mentioned fingerprint adhesion (contamination) was applied were pressed and fixed in the state of the pressure-bonding scale 50, and the amount of fingerprint adhesion was measured. Then, a fingerprint adhesion amount was obtained by using a calibration curve (the creation method is the same as when the scale is 100) of the absorption intensity and the adhesion amount of contaminants obtained in advance at a compression scale of 50. As a result, 0.05 mg fingerprint adhesion similar to the above measurement was confirmed. From this result, even when the intensity of the light detected from the optical waveguide substrate changes due to the variation in the degree of adhesion between the optical waveguide substrate and the test specimen, the intensity can be corrected by using an appropriate calibration curve. It can be said that it will be possible. More specifically, a calibration curve when the pressure of the crimping jig (adhesion between the optical waveguide substrate and the test specimen) is changed is obtained in detail, and this is converted into a database. If used in combination, it can be said that automatic intensity correction on the measuring device side is also possible.

  Next, after cleaning the contaminants (artificial fingerprint liquid) adhering to each specimen by the following method, the degree of contamination of each specimen is evaluated again to recover from the contamination of each specimen. The degree was evaluated.

(Contaminant cleaning treatment)
A wiping item (Kimwipe) is wound around the indenter part of Haydon's abrasion tester TYPE F, and the sample is evaluated for adhesion. A cleaning treatment was performed.

(Evaluation of degree of recovery from contamination of each specimen)
After the washing, a spectral absorption spectrum was obtained with a spectrophotometer in the same manner as the above-described contamination evaluation test. As a result, it was confirmed that 0.01 mg of fingerprint remained on the surface of the test specimen subjected to the cleaning treatment by using the calibration curves for both the pressure scales of 100 and 50.

  Originally, when the evanescent wave absorption characteristic is strictly examined, it is necessary to measure by pressing the test body strongly against the optical waveguide substrate as the pressure scale 100, but according to the above result, it is not always necessary. Recognize. If the test specimen is strongly pressure-bonded to the optical waveguide substrate with the pressure-bonding scale set to 100, the quartz optical waveguide substrate is likely to be damaged. Therefore, in quality control at the factory, it is desired to evaluate with the simple pressure-bonding scale 50. Even in this case, by using an appropriate calibration curve, it is possible to evaluate the fingerprint adhesion and fingerprint wiping performance with high reproducibility and high accuracy.

[Comparative Example 1]
Three specimens were prepared, and the specimen was subjected to artificial contamination treatment in the same manner as “(Contamination of specimen (fingerprint adhesion))” in Example 1. The degree of contamination of this specimen was evaluated by human eyes (visual observation).

  Visual evaluation was performed as follows. First, an evaluation index sample was prepared in which the degree of fingerprint adhesion (contamination) was changed in five stages. And this evaluation index sample and the test body which performed the said contamination process were put in order, and visual observation was performed under the same illumination light. The evaluation was carried out by setting the evaluation level to the closest level based on the five-level evaluation sample. Here, “level 1” is set when the contamination is the worst, and “level 5” is set when the level of cleanliness is the same as that of the unattached surface of the fingerprint. Evaluation was performed by five different observers. The obtained results are shown in Table 2.

  Next, the test specimen was cleaned in the same manner as in “(Contaminant cleaning process)” in Example 1. Then, after the cleaning treatment, the degree of recovery from contamination of the test specimen was evaluated by the same method as visual observation using the above five-step evaluation index samples.

  From the above results, it can be seen that even if the illumination is the same, the way of feeling the degree of contamination varies depending on the person, and in particular, the evaluation level varies greatly after the cleaning process. It can be said that there is a problem in reliability and reproducibility as an evaluation and evaluation method by human eyes.

  The contamination evaluation method, the contamination evaluation apparatus, and the manufacturing method of the present invention are preferably used in various fields such as an optical film such as an antireflection film for a display and an antireflection film for a touch panel, and an optical disk such as a CD and a DVD. Can do.

It is a principle figure of a slab type | mold optical waveguide spectroscopy. It is a typical block diagram which shows an example of the spectrum measuring apparatus using the slab type | mold optical waveguide which can be utilized as a pollution evaluation apparatus. It is the typical top view which expanded and showed the peripheral part of the slab type | mold optical waveguide. It is typical sectional drawing which expanded and showed the peripheral part of the slab type | mold optical waveguide.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,52 Optical waveguide board | substrate 2 Light 3, 3a, 3b Test body 4 Evanescent wave 10 Light source 11 Incident light side lens 12 Incident light side prism 13 Slab type | mold optical waveguide 14 Outgoing light side prism 15 Outgoing light side lens 16 Position control mechanism 30 Optical chopper 31 Incident light side optical fiber 32 Optical fiber 33, 34 Lens 41 Spectroscope 42 Computer 43 Photomultiplier tube 44 Amplifier 51 Substrate

Claims (13)

  The light is incident on one end side of the optical waveguide substrate in a state in which the test body is in close contact with one of the pair of facets facing each other in parallel of the optical waveguide substrate of the slab type optical waveguide. A contamination evaluation method characterized by evaluating the degree of contamination of the surface of the test body in contact with the optical waveguide substrate by detecting light emitted from the end side.   The contamination evaluation method according to claim 1, wherein the surface of the specimen is artificially contaminated.   The contamination evaluation method according to claim 2, wherein the artificial contamination is contamination due to fingerprint adhesion.   After evaluating the degree of contamination of the surface of the specimen, the surface of the specimen is washed, and the degree of recovery from the contamination of the surface is evaluated by evaluating the degree of contamination of the specimen again. The contamination evaluation method according to any one of claims 1 to 3.   When the intensity of light emitted from the other end side changes due to a change in the degree of adhesion of the specimen on the optical waveguide substrate, the intensity is corrected and the degree of contamination on the surface of the specimen is evaluated. The contamination evaluation method according to any one of claims 1 to 4, wherein:   An optical waveguide substrate on which the test body is placed in close contact; a light source that makes light incident on one end of the optical waveguide substrate; and a detector that detects light emitted from the other end of the optical waveguide substrate. Contamination evaluation apparatus characterized by that.   7. The apparatus according to claim 6, further comprising a correction mechanism that corrects the intensity when the intensity of light emitted from the other end side is changed due to a change in the degree of adhesion of the test specimen on the optical waveguide substrate. The contamination assessment device described. Obtaining an optical member;
In a state where the optical member is in close contact with one surface of a pair of facets facing each other in parallel of the optical waveguide substrate of the slab type optical waveguide, light is incident on one end side of the optical waveguide substrate, An inspection step for evaluating the surface state of the optical member in contact with the optical waveguide substrate by detecting light emitted from the other end side;
The manufacturing method of the optical member characterized by having.   The method for manufacturing an optical member according to claim 8, wherein the evaluation of the surface state of the optical member in the inspection step is an evaluation of the degree of contamination performed after artificial contamination.   The method for manufacturing an optical member according to claim 9, wherein the artificial contamination is contamination due to fingerprint adhesion.   In the inspection step, after evaluating the degree of contamination of the surface of the optical member, the surface of the optical member is washed, and the degree of contamination of the optical member is evaluated again, thereby evaluating the degree of recovery from contamination of the surface. The method for producing an optical member according to claim 8, wherein the optical member is produced.   In the inspection step, when the intensity of light emitted from the other end side is changed due to a change in the degree of adhesion of the optical member on the optical waveguide substrate, the surface of the surface of the optical member is corrected by correcting the intensity. A state is evaluated, The manufacturing method of the optical member of any one of Claims 8-11 characterized by the above-mentioned.   The said optical member is an optical film, The manufacturing method of the optical member of any one of Claims 8-12 characterized by the above-mentioned.