JP2011203063A - Method and system for treating/observing transparent film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply observe whether treatment is satisfactory in plasma-treating a transparent film by a reactive gas containing a polymeric monomer.SOLUTION: The reactive gas containing a polymeric monomer is blown out from a nozzle 14 of a plasma processing apparatus 10, put into contact with a transparent film 9 to be treated, and plasma generated under a pressure close to an atmospheric one is applied to the transparent film 9. Subsequently, illumination light 30 is applied to the film 9 from an illuminator 21 of an observation device 20 to image the film 9 by an imager 22. A photoreceptive surface 22a of the imager 22 is disposed in a position where the illumination light 30 does not enter directly.

Description

  The present invention relates to a method and system for observing the surface treatment state of a transparent film after the surface treatment, and more particularly to a treatment observation method and system suitable for an adhesive improvement treatment of a protective film for a polarizing plate.

Patent Document 1 describes a surface treatment method in which a polymerizable monomer such as acrylic acid is vaporized and sprayed onto a protective film for a polarizing plate, and plasma generated under the vicinity of atmospheric pressure is irradiated. Thereby, a polymer film of a polymerizable monomer such as acrylic acid is formed on the surface of the protective film. This polymerized film becomes an adhesion promoting layer, and the protective film can be securely bonded to the polarizing film.
Patent Document 2 describes a system for optically observing defects in a transparent optical film.

International Publication WO2009 / 008284 JP 2008-175609 A

An optical film such as a protective film for the polarizing plate is transparent. According to the surface treatment described in the above-mentioned Patent Document 1, a polymer film of a polymerizable monomer such as acrylic acid is formed on the surface of the film. This polymer film is generally colorless and transparent, and the thickness of the polymer film Is extremely small, on the order of nanometers. For this reason, even if the treatment is insufficient due to, for example, a defect in the vaporizer that vaporizes the polymerizable monomer, it is difficult to distinguish it from a film that has been treated well.
The present invention has been made in view of the above circumstances. For example, when plasma processing is performed on a transparent film applied to an optical device such as a polarizing plate with a reactive gas containing a polymerizable monomer, the quality of the processing is determined. It is an object of the present invention to provide a method and system that can be easily observed.

  In order to solve the above problems, a film processing observation method according to the present invention is a plasma processing step of bringing a reactive gas containing a polymerizable monomer into contact with a transparent film to be processed and irradiating a plasma generated under atmospheric pressure. And an observing step of irradiating the processed film after the plasma processing step with illumination light and observing an image of the processed film viewed from a position where the illumination light is not directly incident. To do.

In the plasma treatment step, the polymerizable monomer in the reaction gas adheres to the film to be treated, and is plasma polymerized to bond with the surface molecules of the film to be treated (graft polymerization). Thereby, a polymer film of a polymerizable monomer is formed on the surface of the film to be processed. This polymerized film is generally colorless and transparent and has a very small thickness (nano order).
When the surface treatment in the plasma treatment process is not performed due to some trouble or is insufficient, most of the illumination light in the observation process is transmitted straight through the film to be treated. Therefore, at a position where the illumination light is not directly incident, it is difficult to obtain an observation image of the film to be processed, or the brightness of the observation image is dark.
When the surface treatment in the plasma treatment process is good, the illumination light in the observation process is scattered by the polymer film of the polymerizable monomer. A part of the scattered light enters the observation position. Accordingly, an observation image of the film to be processed is obtained, or the brightness of the observation image becomes bright. Thereby, even if the to-be-processed film and the polymer film are transparent and the film thickness of the polymer film is extremely small, it can be easily determined whether or not the surface treatment has been sufficiently performed in the plasma treatment process.
The observation includes not only taking an image of the observed part with an imaging means such as a camera, but also directly observing the observed part by a person.

The part (observed part) to be observed in the observation step is preferably a part (irradiated part) where the irradiation light directly enters the film to be treated. Thereby, the difference of the brightness etc. of the observation image according to the quality of the surface treatment of a to-be-processed film can be clarified, and the quality of processing can be determined more easily. It is also easy to identify locations such as processing defects.
The observed part may be displaced from the irradiated part.

The film processing observation system according to the present invention comprises a plasma processing apparatus for bringing a reaction gas containing a polymerizable monomer into contact with a transparent film to be processed and irradiating plasma generated under atmospheric pressure;
An observation apparatus for observing the film to be processed through the plasma processing apparatus;
And the observation device includes an illuminating unit that irradiates the film to be processed with illuminating light, and an imaging unit having a light receiving surface directed to the film to be processed. It is characterized by being arranged at a position not to be.

In the plasma processing apparatus, the polymerizable monomer in the reaction gas adheres to the film to be processed, and is plasma-polymerized to bond with the surface molecules of the film to be processed (graft polymerization). Thereby, a polymer film of a polymerizable monomer is formed on the surface of the film to be processed. The film to be treated after the surface treatment is observed with an observation device.
If the plasma processing apparatus has some problems and the surface treatment has not been performed or has been insufficient, most of the illumination light of the illuminating means of the observation apparatus passes straight through the film to be processed. Therefore, it is difficult to obtain an observation image of the film to be processed or the brightness of the observation image is dark in the imaging unit at the observation position where the illumination light is not directly incident.
When the surface treatment in the plasma processing apparatus is good, the illumination light of the illumination means is scattered by the polymerized monomer polymer film. A part of the scattered light is incident on the imaging means at the observation position. Accordingly, an observation image of the film to be processed is obtained, or the brightness of the observation image becomes bright. Thereby, even if the to-be-processed film and the polymer film are transparent and the film thickness of the polymer film is extremely small, it can be easily determined whether or not the surface treatment has been sufficiently performed by the plasma processing apparatus.
Preferably, the plasma processing apparatus includes a pair of electrodes, and a discharge space in the vicinity of atmospheric pressure for the plasma irradiation is formed between the electrodes.

The observation apparatus for film surface treatment according to the present invention is an apparatus for observing a transparent film to be treated that has been subjected to a treatment gas that is brought into contact with a reactive gas containing a polymerizable monomer and passed through a discharge space near atmospheric pressure,
An illumination unit that irradiates illumination light to the film to be processed; and an imaging unit that has a light receiving surface facing the film to be processed, and the light receiving surface is disposed at a position where the illumination light is not directly incident. It is characterized by.
If the above treatment is not performed or is insufficient, most of the illumination light of the illumination means is transmitted straight through the film to be treated. Therefore, it is difficult to obtain an observation image of the film to be processed or the brightness of the observation image is dark in the imaging unit at the observation position where the illumination light is not directly incident. When the said process is favorable, the illumination light of an illumination means is scattered by the polymeric film | membrane of a polymerizable monomer. A part of the scattered light is incident on the imaging means at the observation position. Accordingly, an observation image of the film to be processed is obtained, or the brightness of the observation image becomes bright. Thereby, even if the said to-be-processed film and a polymer film are transparent and the film thickness of a polymer film is very small, it can be discriminate | determined easily whether the said process was fully performed.

It is preferable that the light receiving axis of the imaging means is directed to a portion (irradiated portion) where the irradiation light directly enters the processed film.
Thereby, the scattered light in the case where the processing is good enters the imaging unit substantially along the light receiving axis of the imaging unit. Therefore, the difference in the observation image according to the quality of the treatment becomes clearer, and the quality of the surface treatment can be determined more easily.
The light receiving axis of the imaging means may be displaced from the irradiated portion.

The film processing observation system preferably further includes a transport mechanism that transports the film to be processed in the order of the plasma processing apparatus and the observation apparatus. By continuously conveying the film to be processed from the plasma processing apparatus to the observation apparatus, the surface treatment by the plasma processing apparatus and the observation by the observation apparatus can be continuously performed, and the observation can be performed immediately after the surface treatment. In this case, it is preferable that the film to be processed is a continuous film, and the transport mechanism includes a feeding roll, a guide roll, and a take-up roll. Furthermore, it is preferable that at least one of the electrodes of the plasma processing apparatus is a rotatable roll electrode, and a film to be processed made of the continuous film is wound around the roll electrode.
It is preferable that the imaging unit is a line sensor camera having a linear imaging region orthogonal to the transport direction. Thereby, the surface state of the film to be processed can be observed in the width direction (imaging area direction) and the extending direction of the film to be processed, and the uniformity of the surface treatment can be confirmed.

The surface treatment is preferably performed near atmospheric pressure. Here, the vicinity of atmospheric pressure refers to a range of 1.013 × 10 ⁴ Pa to 50.663 × 10 ⁴ Pa, and considering the ease of pressure adjustment and the simplification of the apparatus configuration, 1.333 × 10 ^4. Pa~10.664 × ¹⁰ 4 Pa, and more preferably from ^{9.331 × 10 4 Pa~10.397 × 10 4} Pa.

The present invention is suitable for the treatment of hard-to-adhere optical resin films. In adhering the hard-to-adhesive optical resin film to the easily-adhesive optical resin film, It is suitable for improving.
Examples of the main component of the hardly adhesive optical resin film include triacetate cellulose (TAC), polypropylene (PP), polyethylene (PE), cycloolefin polymer (COP), cycloolefin copolymer (COC), and polyethylene terephthalate. (PET), polymethyl methacrylate (PMMA), polyimide (PI) and the like.

  Examples of the main component of the easily adhesive optical resin film include polyvinyl alcohol (PVA) and ethylene vinyl acetate copolymer (EVA).

In the surface treatment for improving the adhesion of the hardly adhesive optical resin film, it is preferable to use a polymerizable monomer as the reaction component.
Examples of the polymerizable monomer include monomers having an unsaturated bond and a predetermined functional group. The predetermined functional group is preferably selected from a hydroxyl group, a carboxyl group, an acetyl group, a glycidyl group, an epoxy group, an ester group having 1 to 10 carbon atoms, a sulfone group, and an aldehyde group. A hydrophilic group is preferred.

Examples of the monomer having an unsaturated bond and a hydroxyl group include ethylene glycol methacrylate, allyl alcohol, and hydroxyethyl methacrylate.
Examples of the monomer having an unsaturated bond and a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-methacryloylpropionic acid and the like.
Examples of the monomer having an unsaturated bond and an acetyl group include vinyl acetate.
Examples of the monomer having an unsaturated bond and a glycidyl group include glycidyl methacrylate.
Monomers having an unsaturated bond and an ester group include methyl acrylate, ethyl acrylate, butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid. Examples include butyl, t-butyl methacrylate, isopropyl methacrylate, and 2-ethyl methacrylate.
Examples of the monomer having an unsaturated bond and an aldehyde group include acrylic aldehyde and crotonaldehyde.

Preferably, the polymerizable monomer is a monomer having an ethylenically unsaturated double bond and a carboxyl group. Examples of such monomers include acrylic acid (CH ₂ ═CHCOOH) and methacrylic acid (CH ₂ ═C (CH ₃ ) COOH). The polymerizable monomer is preferably acrylic acid or methacrylic acid. Thereby, the adhesiveness of a hardly-adhesive resin film can be improved reliably. More preferably, the polymerizable monomer is acrylic acid.

The polymerizable monomer may be conveyed by a carrier gas. The carrier gas is preferably selected from an inert gas such as nitrogen, argon or helium. From the economical viewpoint, it is preferable to use nitrogen as the carrier gas.
Many polymerizable monomers such as acrylic acid and methacrylic acid are in a liquid phase at normal temperature and pressure. Such a polymerizable monomer may be vaporized in a carrier gas such as an inert gas. As a method of vaporizing the polymerizable monomer into the carrier gas, a method of extruding a saturated vapor on the surface of the polymerizable monomer solution with the carrier gas, a method of bubbling the carrier gas into the polymerizable monomer solution, a polymerizable monomer solution For example, a method of promoting evaporation by heating can be used. Extrusion and heating, or bubbling and heating may be used in combination.

  When heating and vaporizing, it is preferable to select a polymerizable monomer having a boiling point of 300 ° C. or less in consideration of the burden on the heater. Moreover, it is preferable to select a polymerizable monomer that does not decompose (chemically change) by heating.

  According to the present invention, after a transparent film is plasma-treated with a reactive gas containing a polymerizable monomer, the treatment state can be observed.

It is explanatory drawing which shows schematic structure of the film processing observation system which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the to-be-processed film 9 is a transparent resin film for optics, and has a continuous sheet shape. Here, a protective film for a polarizing plate is applied as the film 9 to be processed. The protective film 9 contains triacetate cellulose (TAC) as a main component. The components of the film 9 are not limited to TAC, but polypropylene (PP), polyethylene (PE), cycloolefin polymer (COP), cycloolefin copolymer (COC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polyimide (PI), or the like may be used. The thickness of the film 9 is, for example, about 100 μm.

  A polarizing film made of a PVA film and a protective film are bonded together with an adhesive to constitute a polarizing plate. As the adhesive, an aqueous adhesive such as an aqueous PVA solution is used. Prior to the bonding step, the protective film is surface-treated by the film processing observation system 1 to improve the adhesion of the protective film.

  As shown in FIG. 1, the film processing observation system 1 includes a plasma processing apparatus 10 and an observation apparatus 20. The plasma processing apparatus 10 includes electrodes 11 and 12 and a reactive gas nozzle 14. The electrodes 11 and 12 are both constituted by cylindrical roll electrodes. Roll electrodes 11 and 12 are arranged in parallel to each other with their respective axes directed in the processing width direction perpendicular to the paper surface of FIG. A narrow gap 13 is formed between the roll electrodes 11 and 12. One of the pair of electrodes 11 and 12 is connected to a power source (not shown). The other electrode is electrically grounded. The power source supplies, for example, pulsed power to the electrodes 11 and 12. As a result, an electric field is applied between the pair of electrodes 11 and 12, plasma is generated in the gap 13 near atmospheric pressure, and the gap 13 becomes a discharge space near atmospheric pressure.

  The film 9 to be processed is fed from a feed roll (not shown), and is wound about a half turn on the upper peripheral surface of the roll electrodes 11 and 12 with the width direction orthogonal to the paper surface in FIG. The film to be treated 9 is passed through the discharge space 13 along the peripheral surfaces of the roll electrodes 11 and 12, is hung below the discharge space 13, and is folded back by the guide rolls 15 and 15. Further, the film to be processed 9 is wound around a guide roll 25 of the observation device 20 and then wound around a winding roll (not shown).

  As schematically shown in FIG. 1, a rotating mechanism 3 is connected to each of the roll electrodes 11, 12 (illustration of a connecting line between the rotating mechanism 3 and the electrode 12 is omitted in the figure). The rotation mechanism 3 includes a driving unit such as a motor and a transmission unit that transmits the driving force of the driving unit to the shafts of the roll electrodes 11 and 12. The transmission means is constituted by, for example, a belt / pulley mechanism or a gear train. By the rotation mechanism 3, the roll electrodes 11 and 12 are rotated around their own axes and in the same direction (clockwise in FIG. 1) in synchronization with each other. Thereby, the to-be-processed film 9 is conveyed in the substantially right direction from the 1st roll electrode 11 to the 2nd roll electrode 12. FIG. The conveyance speed of the to-be-processed film 9 is about 10 m / min-30 m / min, for example.

  The rotation mechanism 3, the electrodes 11 and 12, the guide rolls 15 and 25, and a feeding and winding roll (not shown) constitute a transport mechanism for the film 9 to be processed. The electrodes 11 and 12, the guide rolls 15 and 25, and an unillustrated feed and take-up roll constitute a support means for the film 9 to be processed.

  A reactive gas nozzle 14 is disposed above the discharge space 13 between the roll electrodes 11 and 12. The reactive gas nozzle 14 extends long in the processing width direction orthogonal to the paper surface of FIG. A cross section perpendicular to the extending direction of the reaction gas nozzle 14 is tapered downward. The lower end portion (tip portion) of the reactive gas nozzle 14 is inserted into a gradually narrowing portion between the roll electrodes 11 and 12 and faces the discharge space 13. Although not shown in detail, a rectification unit is incorporated in the reactive gas nozzle 14. An outlet is provided on the lower surface of the reactive gas nozzle 14. The outlet is in the form of a slit extending in the processing width direction orthogonal to the paper surface of FIG.

  The reactive gas supply source 2 is connected to the reactive gas nozzle 14 via the reactive gas supply path 2a. The reaction gas from the vaporizer 2 is supplied to the nozzle 14. The reaction gas is made uniform by the rectifying unit and blown out from the blowout port on the lower surface of the nozzle 14. The blow-out flow of the reaction gas is a flow that is uniformly distributed in the processing width direction.

The reaction gas contains a polymerizable monomer as a reaction component. Here, acrylic acid AA is used as the polymerizable monomer. The reaction gas further includes a carrier gas in addition to the reaction component (polymerizable monomer). An inert gas is used as the carrier gas. Here, nitrogen (N ₂ ) is used as an inert gas for the carrier gas. The polymerizable monomer is not limited to acrylic acid, and methacrylic acid, itaconic acid, maleic acid, etc. may be used. Good. The carrier gas is not limited to N _2, and a rare gas such as Ar or He may be used.

The reactive gas supply source 2 is composed of a vaporizer. Acrylic acid AA is stored in the vaporizer as a polymerizable monomer in a liquid state. Nitrogen (N ₂ ) is introduced into the vaporizer as a carrier gas. Acrylic acid is vaporized and mixed with this carrier gas (N ₂ ) to generate a reaction gas (acrylic acid AA + N ₂ ). The carrier gas may be introduced above the liquid acrylic acid level in the vaporizer, or may be introduced into the liquid acrylic acid and bubbled. A part of the carrier gas may be introduced into the vaporizer and the remaining part may not be passed through the vaporizer, and the part of the carrier gas and the remaining part may be merged on the downstream side of the vaporizer. The acrylic acid concentration in the reaction gas can be adjusted according to the temperature of the vaporizer and the distribution ratio of the part and the remainder of the carrier gas. The set temperature of the liquid acrylic acid in the vaporizer 2 is, for example, 120 ° C. to 190 ° C.

The supply path 2a and the nozzle 14 are temperature-controlled by reaction gas temperature adjusting means (not shown). The temperature adjusting means of the supply path 2a is constituted by a ribbon heater, for example. The temperature adjusting means of the nozzle 14 is constituted by, for example, a temperature adjustment path through which a medium such as temperature-controlled water passes. It is preferable that the preset temperature of the reaction gas in the supply path 2a and the nozzle 14 is higher than the condensation temperature of acrylic acid, for example, 50 to 70 ° C.

  Further, temperature control means (not shown) is incorporated in each of the roll electrodes 11 and 12. The temperature adjusting means is constituted by a temperature adjusting path formed in the roll electrodes 11 and 12, for example. The temperature of the roll electrodes 11 and 12 can be controlled by flowing a temperature-controlled medium such as water through the temperature control path. As a result, the to-be-processed film 9 on the peripheral surface of the roll electrodes 11 and 12 can be temperature-controlled. The set temperature of the electrodes 11 and 12 and the film to be processed 9 is preferably lower than the condensation temperature of acrylic acid, and is, for example, 20 ° C to 25 ° C.

  An observation apparatus 20 is disposed on the downstream side of the plasma processing apparatus 10 along the conveyance direction of the film 9 to be processed. In the observation device 20, the film to be processed 9 is supported by a plurality of guide rolls 25 with a certain amount of tension applied thereto. In the figure, the processed film 9 in the observation device 20 is supported horizontally, but may be supported diagonally or vertically.

The observation device 20 includes an illumination unit 21, an imaging unit 22, and a monitor (image display unit) 23.
The illuminating means 21 is composed of a white LED light source having a plurality of LED elements (light emitting elements). The illumination means 21 may be a monochromatic LED light source. The LED light source 21 is arranged below the arrangement position of the film 9 to be processed in the observation device 20. Although not shown in detail, the LED light source 21 extends in a processing width direction (direction perpendicular to the paper surface of FIG. 1) perpendicular to the transport direction of the film 9 to be processed, and the LED elements are arranged in the processing width direction. The light emitting surface 21a of the LED light source 21 extends in the processing width direction. The light emitting surface 21a is directed obliquely to the film 9 to be processed. The light emitting surface 21a is tilted toward the upstream side in the film transport direction from the LED light source 21, but may be tilted toward the downstream side in the film transport direction from the LED light source 21.

  Illumination light 30 is emitted from the light emitting surface 21a. The wavelength of the illumination light 30 is not particularly limited, but is preferably in the visible light range. The optical axis 31 of the illumination light 30 crosses the processing target film 9 obliquely. A portion (irradiated portion) 9 a where the illumination light 30 directly enters the film to be processed 9 is located slightly upstream in the film transport direction from the LED light source 21. The distance D1 from the light emitting surface 21a to the irradiated portion 9a is, for example, D1 = 50 mm to 100 mm, but is not limited thereto, and may be D1 <50 mm or D1> 100 mm. The incident angle α of the illumination light 30 to the film 9 to be processed is, for example, α = 30 ° to 60 °, but is not limited thereto, α = 0 ° to 30 °, α> 60 °, Furthermore, the incident angle α may be larger than the total reflection critical angle. The illumination light 30 is parallel light that maintains a light beam having a substantially constant width, or diffuse light that is close to parallel light. As long as the light emitting surface 21a of the light source 21 is arranged so as to be out of the imaging unit 22 (imaging region), the illumination light 30 may be diffused light or convergent light.

Although detailed illustration is omitted, the illumination light 30 is formed in a line shape in the processing width direction (direction orthogonal to the paper surface of FIG. 1). The irradiated portion 9a in the processed film 9 extends over substantially the entire width direction of the processed film 9 (direction orthogonal to the paper surface of FIG. 1).
The distance L along the film 9 from the discharge space 13 to the irradiated portion 9a is not particularly limited. The irradiated part 9a and the post-observed part may be downstream of the discharge space 13, that is, the polymerization processing part, in the film transport direction.

Next, the imaging means 22 will be described.
The imaging means 22 is constituted by a CCD line sensor camera having a plurality of CCDs (imaging elements). The plurality of CCDs are arranged in the processing width direction (direction perpendicular to the plane of FIG. 1). The line sensor camera 22 has a line-shaped imaging region along the processing width direction (direction perpendicular to the plane of FIG. 1). The imaging area substantially covers the entire width of the film 9 to be processed.

The line sensor camera 22 is arranged on the opposite side (upper side) of the LED light source 21 with the arrangement position of the film 9 to be processed in the observation apparatus 20 interposed therebetween. The line sensor camera 22 is disposed just above the irradiated portion 9a. The light receiving surface 22a of the line sensor camera 22 is directed directly below. The light receiving surface 22a is disposed at a position where the illumination light 30 from the light source 21 is not directly incident. It is preferable that the light emitting surface 21 a of the light source 21 is out of the imaging area of the line sensor camera 22.
The distance D2 between the light receiving surface 22a and the film 9 to be processed is, for example, about D2 = 1000 mm, but may be larger or smaller than this.

  The light receiving axis 22L (the optical axis of the imaging lens) of the line sensor camera 22 is directed to the irradiated portion 9a and intersects the irradiated portion 9a. The light receiving shaft 22 </ b> L is orthogonal to the irradiated portion 9 a and the processed film 9, but may be inclined with respect to the processed film 9. A portion to be observed by the line sensor camera 22 in the film to be processed 9 is coincident with or overlapped with the portion to be irradiated 9 a by the light source 21.

  A monitor 23 is connected to the line sensor camera 22. An image acquired by the line sensor camera 22 is displayed on the monitor 23.

A method for surface-treating and observing the transparent film 9 by the film processing observation system 1 having the above-described configuration will be described.
The surface treatment of the film 9 to be processed includes a plasma treatment process and an observation process. A plasma treatment process is first performed on each portion in the extending direction of the film 9 to be processed, and then an observation process is performed.

[Plasma treatment process]
The plasma processing step is performed by the plasma processing apparatus 10. The roll electrodes 11 and 12 of the plasma processing apparatus 10 are rotated clockwise in FIG. 1 by the rotation mechanism 3 to convey the film 9 to be processed substantially in the right direction.
Electric power is supplied to the electrodes 11 and 12 from a power source (not shown), an electric field is applied between the electrodes 11 and 12, and plasma discharge near atmospheric pressure is generated in the gap 13.

In the vaporizer 2 in a carrier gas _{(N 2)} to vaporize acrylic acid (AA), to produce a reaction gas (AA + _{N 2).} This reactive gas is blown out from the nozzle 14 to the discharge space 13 through the supply path 2a and blown onto the film 9 to be processed. Then, acrylic acid in the reaction gas condenses and adheres to the film 9 to be processed. This acrylic acid is activated by the plasma in the discharge space 13, and double bond cleavage, polymerization and the like occur. Nitrogen in the reaction gas is turned into plasma in the discharge space 13. The film 9 to be treated is irradiated with the nitrogen plasma or plasma light, and bonds such as C—C, C—O, and C—H of the surface molecules of the film 9 to be treated are cut. It is considered that a polymer of acrylic acid is bonded (graft polymerization) to this bond cutting part, or a COOH group decomposed from acrylic acid is bonded. Thereby, the acrylic acid polymer film used as the adhesion promotion layer is formed on the surface of the film 9 to be processed. The thickness of the acrylic acid polymerized film is extremely small, on the order of nanometers.

[Observation process]
The plasma-treated portion of the film 9 to be processed is conveyed to the observation device 20. An observation process is executed by the observation device 20. In the observation step, the illumination light 30 is irradiated from the LED light source 21 of the observation device 20 toward the irradiated portion 9a of the film 9 to be processed. And the direction of the to-be-irradiated part 9a is imaged with the line sensor camera 22. FIG. This image is displayed on the monitor 23. Thereby, the dark field observation of the image of the film 9 to be processed viewed from the position where the illumination light 30 is not directly incident can be performed by the monitor 23.

  If the plasma processing is not sufficiently performed due to malfunction of the plasma processing apparatus 10 (for example, malfunction of the vaporizer 2, etc.), the illumination light 30 is hardly scattered in the processing target film 9, and the processing target film 9 is not scattered. Transmits straight. Light from the LED light source 21 hardly enters the light receiving surface 22a. Therefore, the display image on the monitor 23 becomes dark.

  When the surface treatment by the plasma processing apparatus 10 is satisfactorily performed, the film to be treated 9 is coated with an acrylic acid polymer film, so that a part of the illumination light 30 is scattered by molecules of the acrylic acid polymer film. A part of the scattered light 33 enters the light receiving surface 22 a and is detected by the line sensor camera 22. Therefore, the display image on the monitor 23 becomes bright or whitish. Since the scattered light 33 is incident substantially along the light receiving axis 22L, the difference in brightness of the display image compared to the case of processing failure becomes clearer.

  Therefore, even if the acrylic acid polymer film is colorless and transparent and extremely thin, by observing the film to be processed 9 in the dark field, depending on the presence or absence of the acrylic acid polymer film or the degree of adhesion, the brightness of the observation image is adjusted. You can make a difference. By discriminating the difference in the observed images, it is possible to determine whether the polymer film formation process is good or bad. Since the irradiated portion 9a and the observed portion are coincident with each other, it is possible to easily identify a processing defective portion. By continuously conveying the film 9 to be processed from the plasma processing apparatus 10 to the observation apparatus 20, the plasma treatment process and the observation process can be performed continuously.

  Illumination light 30 is irradiated over substantially the entire width direction of the film to be processed 9 (direction orthogonal to the paper surface of FIG. 1), and the line sensor camera 22 has a line-shaped imaging region extending in the width direction of the film to be processed 9. Thus, almost the entire width direction of the film 9 can be observed at a time. Furthermore, the irradiated position 9a of the to-be-processed film 9 moves because the to-be-processed film 9 is continuously conveyed in the extending direction. Thereby, the surface state of the to-be-processed film 9 can be observed in the width direction and the extending direction, and the uniformity of the surface treatment can be confirmed.

  As a result of observation, when it is recognized that the surface treatment is insufficient or defective, appropriate measures are taken, such as redoing the treatment or disposing the treated film 9 as a defective product. Thereby, only the to-be-processed film 9 by which favorable surface treatment was made | formed can be used as a protective film of a polarizing plate, and it can adhere | attach with the polarizing film which consists of a PVA film etc., and can produce a polarizing plate. An aqueous adhesive such as an aqueous PVA solution is used as the adhesive. Since the adhesiveness of the film to be processed 9 is enhanced in advance by the plasma treatment step and the good surface treatment is confirmed by the observation step, a polarizing plate having sufficient adhesive strength can be obtained with certainty.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the arrangement positions and angles of the illumination unit and the imaging unit can be selected as appropriate.
The light receiving shaft 22 </ b> L of the imaging unit 22 may be displaced from the irradiated portion 9 a of the processed film 9.
The illumination unit 21 may be disposed on the upper side of the processed film 9, and the imaging unit 22 may be disposed on the lower side of the processed film 9.
The imaging unit 22 may be arranged on the same side as the illumination unit 21 with respect to the arrangement position of the film 9 to be processed in the observation apparatus 20. The incident angle of the illumination light 30 on the film 9 to be processed may be larger than the total reflection critical angle, and the imaging unit 22 may be arranged so as to deviate from the luminous flux of the regular reflection light of the illumination light 30.

  The illumination means is not particularly limited, and is not limited to an LED light source, and a fluorescent lamp and other various light emission sources can be applied.

The imaging means 22 is not limited to a line sensor camera, and may be an area sensor camera as long as the light emitting surface 21a of the light source 21 does not enter the imaging region, and other various imaging devices can be applied.
The imaging means may be omitted, and the operator may visually observe the film 9 to be processed from a position where the illumination light 30 is not directly incident.

In the observation device 20, the film 9 to be processed may be stopped and observed.
You may further provide the analysis apparatus which analyzes the image data of the imaging means 22 and determines the quality of the surface treatment state of the to-be-processed film 9. FIG.

The structure of the plasma processing apparatus 10 can be modified as appropriate. For example, a reactive gas containing a polymerizable monomer such as acrylic acid is brought into contact with the film to be processed 9 at a position distant from the discharge space 13 and the polymerizable monomer is condensed on the film to be processed 9 to be processed. The plasma 9 may be generated by adhering to the film 9 and subsequently introducing the film 9 to be treated into the discharge space 13 and supplying a discharge product gas containing no polymerizable monomer to the discharge space 13. Nitrogen or a rare gas (such as argon or helium) is preferably used as the discharge product gas. You may arrange | position the nozzle which blows off discharge production | generation gas or reaction gas inside the folding | turning part by the guide rolls 15 and 15 of the to-be-processed film 9. FIG.
Three roll electrodes and the like are provided side by side to form two discharge spaces 13, a reactive gas containing a polymerizable monomer is supplied to the discharge space 13 upstream of the transport direction, and the polymerizable monomer is supplied to the discharge space 13 downstream of the transport direction It is also possible to supply a discharge product gas that does not contain the gas.
The electrode structure of the plasma processing apparatus 10 is not limited to the roll electrodes 11 and 12, but may be parallel plate electrodes, a pair of roll electrodes and plate electrodes, or a pair of roll electrodes and partially cylindrical concave electrodes.

The to-be-processed film 9 is not restricted to a continuous sheet form, A sheet form may be sufficient.
The to-be-processed film 9 should just be transparent, is not restricted to colorless and transparent, and may be translucent or colored and transparent.

  The present invention can be applied to manufacture of an optical device such as a polarizing plate of a flat panel display (FPD).

1 Film processing observation system 2 Vaporizer (reactive gas source)
2a Reaction gas supply path 3 Rotating mechanism 9 Film to be processed 9a Irradiated portion, observed portion 10 Plasma processing device 11 First electrode 12 Second electrode 13 Discharge space 14 Reactive gas nozzle 15 Guide roll 20 Observation device 21 LED light source (illuminating means) )
21a Light emitting surface 22 Line sensor camera (imaging means)
22a Light receiving surface 22L Light receiving shaft 23 Monitor (image display means)
25 Guide roll 30 Illumination light 31 Irradiation optical axis

Claims (6)

A plasma treatment step of contacting a reaction gas containing a polymerizable monomer with a transparent film to be treated, and irradiating a plasma generated near atmospheric pressure;
An observation step of irradiating the processing target film after the plasma processing step with illumination light and observing an image of the processing target film viewed from a position where the illumination light is not directly incident;
The film processing observation method characterized by performing.   The film processing observation method according to claim 1, wherein, in the observation step, a portion of the film to be processed on which the illumination light directly enters is observed. A plasma processing apparatus for bringing a reactive gas containing a polymerizable monomer into contact with a transparent film to be processed, and irradiating a plasma generated near atmospheric pressure;
An observation apparatus for observing the film to be processed through the plasma processing apparatus;
And the observation device includes an illuminating unit that irradiates the film to be processed with illuminating light, and an imaging unit having a light receiving surface directed to the film to be processed. A film processing observation system, characterized in that the film processing observation system is arranged at a position not to be used.   The film processing observation system according to claim 3, wherein a light receiving axis of the image pickup unit is directed to a portion of the film to be processed on which the illumination light is directly incident.   The apparatus further includes a transport mechanism that transports the film to be processed in the order of the plasma processing apparatus and the observation apparatus, and the imaging unit is a line sensor camera having a linear imaging region orthogonal to the transport direction. The film processing observation system according to claim 3 or 4. An apparatus for observing a transparent film to be treated which has been subjected to a treatment in which a reactive gas containing a polymerizable monomer is brought into contact and passed through a discharge space near atmospheric pressure,
An illumination unit that irradiates illumination light to the film to be processed; and an imaging unit that has a light receiving surface facing the film to be processed, and the light receiving surface is disposed at a position where the illumination light is not directly incident. An observation apparatus for film surface treatment characterized by the above.