WO2021124646A1 - Inspection method, inspection device, and inspection system - Google Patents

Inspection method, inspection device, and inspection system Download PDF

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Publication number
WO2021124646A1
WO2021124646A1 PCT/JP2020/037525 JP2020037525W WO2021124646A1 WO 2021124646 A1 WO2021124646 A1 WO 2021124646A1 JP 2020037525 W JP2020037525 W JP 2020037525W WO 2021124646 A1 WO2021124646 A1 WO 2021124646A1
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Prior art keywords
polarizing plate
retardation
film
linear polarizing
axis
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PCT/JP2020/037525
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French (fr)
Japanese (ja)
Inventor
信次 小林
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住友化学株式会社
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Publication of WO2021124646A1 publication Critical patent/WO2021124646A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements

Definitions

  • the present invention relates to an inspection method, an inspection device, and an inspection system.
  • the retardation film can convert linearly polarized light into circularly polarized light or elliptically polarized light, and conversely, can convert circularly polarized light or elliptically polarized light into linearly polarized light, this retardation film and linearly polarized light are combined (elbow). Circularly polarized light is applied to an organic EL display device and a reflective liquid crystal display device.
  • the retardation film obtained by orienting and curing a polymerizable liquid crystal compound is an extremely thin film, and has been attracting attention in manufacturing a thin display device (for example, patent documents). 1).
  • a liquid composition containing a polymerizable liquid crystal compound is applied to a long base film to form a thin film, and the polymerizable liquid crystal compound in the thin film is formed. Is oriented in the desired direction and then irradiated with active energy rays. As a result, the oriented polymerizable liquid crystal compound is cured to form a retardation film.
  • an alignment film may be formed on the base film before the liquid composition is applied to the base film.
  • the orientation of the polymerizable liquid crystal compound may be disturbed at the dust portion and defects may occur.
  • the base film has an in-plane retardation, it tends to be difficult to inspect the presence or absence of defects in the retardation film formed on the base film by an optical method. Since the base film that can be inexpensively obtained from the market is generally produced by stretching, the fact is that the inexpensive base film is difficult to use for the inspection of the retardation film produced by the above method.
  • the present invention provides an inspection method, an inspection apparatus, and an inspection apparatus capable of inspecting the presence or absence of defects in a retardation film made of a cured product of a polymerizable liquid crystal compound while suppressing the influence of the in-plane retardation of the base film.
  • the purpose is to provide an inspection system.
  • the present invention is a film-like substrate comprising a base film having an in-plane retardation value of 50 nm or more at a wavelength of 550 nm and a retardation film made of a cured product of a polymerizable liquid crystal compound formed on one side of the base film.
  • This is an inspection method in which light is incident on an inspection object to determine the presence or absence of defects in the retardation film, and the first linear polarizing plate, the object to be inspected, the retardation filter, the second linear polarizing plate, and the like.
  • the surface on the base film side faces the first linear polarizing plate side, and the slow axis of the base film and the first linear polarizing plate or the first linear polarizing plate or the first
  • the transmission axes of the linearly polarizing plate No. 2 are substantially orthogonal to or substantially parallel to each other, and the slow axis of the retardation film and the slow axis of the retardation filter are substantially parallel to each other, and the retardation film of the retardation film.
  • the in-plane retardation value at a wavelength of 550 nm is 300 nm or less, and the total of the in-plane retardation value at a wavelength of 550 nm of the retardation film and the in-plane retardation value at a wavelength of 550 nm of the retardation filter is 250 nm to 300 nm.
  • the transmission axis of the first linearly polarized light and the absorption axis of the second linearly polarized light are substantially linearly symmetric with the slow axis of the retardation film as the axis of symmetry.
  • an inspection method for observing a second linear polarizing plate or a first linear polarizing plate from the side is provided.
  • the transmission axes of the first linear polarizing plate or the second linear polarizing plate are arranged so as to be substantially orthogonal to or substantially parallel to the slow axis of the substrate film having a retardation. Therefore, the polarization state of the light that has passed through the linear polarizing plate is not disturbed by the base film. That is, the assembled optical system functions as intended, and when there is a defect in the retardation film, the defect can be appropriately recognized in the observation field of view.
  • the total of the in-plane retardation value at the wavelength of 550 nm of the retardation film and the in-plane retardation value at the wavelength of 550 nm of the retardation filter is 250 nm to 300 nm, and from the optical axis direction of light.
  • the slow axis of the retardation film is set as the axis of symmetry, and the transmission axis of the first linearly polarizing plate and the absorption axis of the second linearly polarizing plate are arranged so as to be substantially line-symmetrical.
  • the linearly polarized light that has passed through the film and the phase difference filter will have a phase difference of about ⁇ / 2 before and after that.
  • the transmission axis of the first linear polarizing plate or the second linear polarizing plate can be used as the slow axis of the base film. They can be arranged so as to be substantially orthogonal to each other or substantially parallel to each other.
  • a liquid composition containing a polymerizable liquid crystal compound is applied to one side of the base film and polymerized on the surface of the base film. It may have a step of forming a coating film containing a property liquid crystal compound and orienting and curing the polymerizable liquid crystal compound contained in the coating film to form a retardation film. This makes the production of the retardation film more efficient.
  • the object to be inspected is continuously inspected in the length direction while being conveyed between the first linear polarizing plate and the retardation filter in the length direction of the object to be inspected. You may. This makes the inspection of the object to be inspected more efficient.
  • a plurality of inspection areas may be provided in the width direction of the object to be inspected. Since the base film is generally produced by stretching in at least one direction, the direction of the slow axis is often different in the width direction. Therefore, by dividing the inspection area in the width direction of the object to be inspected and performing the inspection in each inspection area, the inspection in which the influence of the in-plane retardation of the base film is suppressed in each part in the width direction can be performed. It can be carried out.
  • the present invention is in the form of a film including a base film having an in-plane retardation value of 50 nm or more at a wavelength of 550 nm and a retardation film made of a cured product of a polymerizable liquid crystal compound formed on one side of the base film.
  • a first linear polarizing plate and a retardation filter arranged so as to sandwich a place where the object to be inspected is placed, which is an inspection device for determining the presence or absence of defects in the retardation film by injecting light into the object to be inspected.
  • the second linear polarizing plate arranged in the region opposite to the place where the inspected object is arranged with respect to the retardation filter, and the inspected object with respect to the first linear polarizing plate or the second linear polarizing plate.
  • a light source arranged in a region opposite to the place where it is arranged is provided, and the transmission axis of the first linear polarizing plate or the second linear polarizing plate is substantially orthogonal to the slow axis of the base film.
  • the retardation filter is arranged so that its slow axis is substantially parallel to the slow axis of the retardation film, and the wavelength of the retardation filter is substantially parallel to each other.
  • the in-plane retardation value at 550 nm is a value at which the total of the in-plane retardation value at the wavelength of 550 nm of the retardation film is 250 nm to 300 nm, and the retardation of the retardation film is delayed when viewed from the optical axis direction of light.
  • the transmission axis of the first linearly polarizing plate and the absorption axis of the second linearly polarizing plate are arranged so as to be substantially linearly symmetric, and the light source is the first on the optical axis.
  • an inspection apparatus in which a linear polarizing plate, a predetermined inspection region on an object to be inspected, a retardation filter, and a second linear polarizing plate are arranged at a lined position.
  • the transmission axes of the first linear polarizing plate or the second linear polarizing plate are arranged so as to be substantially orthogonal to or substantially parallel to the slow axis of the substrate film having a retardation. Therefore, the polarization state of the light that has passed through the linear polarizing plate is not disturbed by the base film. That is, the assembled optical system functions as intended, and when there is a defect in the retardation film, the defect can be appropriately recognized in the observation field of view.
  • the total of the in-plane retardation value at the wavelength of 550 nm of the retardation film and the in-plane retardation value at the wavelength of 550 nm of the retardation filter is 250 nm to 300 nm, and from the optical axis direction of light.
  • the slow axis of the retardation film is set as the axis of symmetry, and the transmission axis of the first linearly polarizing plate and the absorption axis of the second linearly polarizing plate are arranged so as to be substantially line-symmetrical.
  • the linearly polarized light that has passed through the film and the phase difference filter will have a phase difference of about ⁇ / 2 before and after that.
  • the above-mentioned inspection device an alignment angle measuring device for determining the slow axis of the base film before the retardation film is formed, and a slow phase of the base film obtained by the alignment angle measuring device.
  • an inspection system including an angle adjusting mechanism for adjusting the angle of the first linear polarizing plate so that the axis and the transmission axis of the first linear polarizing plate are substantially orthogonal to each other or substantially parallel to each other. If the direction of the slow axis of the base film is unknown, by obtaining this in advance, the transmission axis of the first linear polarizing plate or the second linear polarizing plate can be used as the slow axis of the base film. They can be arranged so as to be substantially orthogonal to each other or substantially parallel to each other. Further, by providing the angle adjustment mechanism, the angle adjustment can be automated.
  • an inspection method and an inspection apparatus capable of inspecting the presence or absence of defects in a retardation film made of a cured product of a polymerizable liquid crystal compound while suppressing the influence of the in-plane retardation of the base film. And an inspection system can be provided.
  • FIG. (A) is a diagram showing the relationship between the transmission axis of the first linear polarizing plate and the absorption axis of the second linear polarizing plate and the slow axis of the retardation film in the first embodiment.
  • (B) is a view of (A) viewed from the optical axis side. It is a figure which shows the inspection system of 1st Embodiment. It is a partial perspective view which shows the arrangement of a plurality of inspection apparatus in the inspection system of 1st Embodiment. It is a top view which shows the state of the slow-phase axis of a base film. It is a figure which shows the inspection apparatus of 2nd Embodiment.
  • Refractive index (nx, ny, nz) “Nx" is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), “ny” is the direction orthogonal to the slow-phase axis in the in-plane, and “nz” is the thickness direction.
  • Refractive index (Re ( ⁇ )) refers to the in-plane retardation value of the film at 23 ° C. and a wavelength of ⁇ (nm).
  • Re ( ⁇ ) (nx ⁇ ny) ⁇ d, where d (nm) is the thickness of the film.
  • Phase difference value in the thickness direction The phase difference value in the thickness direction (Rth ( ⁇ )) refers to the phase difference value in the thickness direction of the film at 23 ° C. and a wavelength of ⁇ (nm).
  • Rth ( ⁇ ) ((nx + ny) / 2-nz) ⁇ d, where d (nm) is the thickness of the film.
  • the inspection device of the present embodiment inspects the presence or absence of surface defects of the retardation film.
  • the inspection device 1A the light source 2, the first linear polarizing plate 3, the retardation filter 4, the second linear polarizing plate 5, and the camera (detecting means) 6 are arranged in this order. It is something that has been done.
  • the inspection device 1A is provided with a place for arranging the inspected object 10 to be inspected between the first linear polarizing plate 3 and the retardation filter 4, and in FIG. 1, the inspected object 10 is placed there. It depicts how it was placed in.
  • the object 10 to be inspected includes a retardation film 7A which is a main body to be inspected, and a base film 8A in which the retardation film 7A is laminated on one side.
  • the retardation film 7A it is used as a circular polarizing plate in a display device, for example, a liquid crystal display device or an organic EL display device in combination with a linear polarizing plate.
  • the term "circularly polarized light” includes a circularly polarizing plate and an elliptical polarizing plate. Further, “circularly polarized light” includes circularly polarized light and elliptically polarized light.
  • the retardation film 7A has an in-plane retardation value of 300 nm or less at a wavelength of 550 nm of the retardation film.
  • the retardation film 7A is a ⁇ / 4 plate.
  • the retardation film 7A is made of a cured product of a polymerizable liquid crystal compound.
  • the retardation film 7A made of a cured product of a polymerizable liquid crystal compound usually has a thin thickness of about 0.2 ⁇ m to 10 ⁇ m, and when foreign matter or the like is contained, the retardation value tends to decrease at that portion.
  • the polymerizable liquid crystal compounds capable of forming the retardation film 7A are described in, for example, JP-A-2009-173893, JP-A-2010-31223, WO2012 / 147904, WO2014 / 10325 and WO2017-43438. The disclosed ones can be mentioned.
  • the polymerizable liquid crystal compounds described in these publications can form a retardation film having so-called anti-wavelength dispersibility, which enables uniform polarization conversion in a wide wavelength range.
  • a solution containing the polymerizable liquid crystal compound (polymerizable liquid crystal compound solution; liquid composition) is applied (coated) on the base film 8A to form a coating film.
  • the base film 8A may be provided with an alignment film for orienting the polymerizable liquid crystal compound.
  • the alignment film may be either photo-aligned by polarization irradiation or mechanically oriented by rubbing treatment. As a specific example of such an alignment film, those described in the above publication can be used.
  • the retardation film 7A formed in this manner is bonded together with the base film 8A to another film, and then the base film 8A is peeled off to transfer the retardation film 7A onto the other film. can do.
  • the polymerizable liquid crystal compound solution When forming the retardation film 7A, if foreign matter or the like is present on the base film 8A to which the polymerizable liquid crystal compound solution is applied, or if the base film 8A itself is scratched or the like, the polymerizable liquid crystal compound solution is used. Defects may occur in the coating film itself obtained by coating. Further, when the alignment film is rubbed, debris of the rubbing cloth remains on the alignment film, which may cause a defect in the coating film of the polymerizable liquid crystal compound solution (composition for forming a liquid crystal cured film). As described above, when the retardation film is formed from the polymerizable liquid crystal compound, it is possible to form the retardation film having an extremely thin thickness, but the above-mentioned dusts and scratches cause optical defects in the retardation film. May be a factor
  • the base film 8A to which the polymerizable liquid crystal compound solution is applied is in a laminated state with the retardation film 7A at the time of defect inspection of the retardation film 7A, it is desirable that the retardation value is small.
  • the base film 8A has an in-plane retardation value of 50 nm or more at a wavelength of 550 nm.
  • the in-plane retardation value may be 100 nm or more, 500 nm or more, 1000 nm or more, 2000 nm or more, 5000 nm or more, 8000 nm or more. It may be. Even when the base film 8A has such a retardation, according to the inspection apparatus of the present embodiment, defects of the retardation film 7A are not affected by the retardation of the base film 8A. The presence or absence can be easily determined.
  • the material constituting the base film 8A examples include those described in the above-mentioned publication, and polyethylene terephthalate (PET) is particularly preferable.
  • the thickness of the base film 8A may be 10 to 500 ⁇ m, 30 to 300 ⁇ m, 50 to 200 ⁇ m, or 80 to 150 ⁇ m.
  • the first linear polarizing plate 3 is a film that converts the light incident from the light source 2 into linearly polarized light, and is formed by laminating a protective film on at least one surface of the polarizing film.
  • the polarizing film include a polyvinyl alcohol film in which iodine and a dichroic dye are adsorbed and oriented, and a film in which a polymerizable liquid crystal compound is oriented and polymerized and a dichroic dye is adsorbed and oriented. Be done.
  • the linear polarizing plate has an absorption axis in a transmission axis direction for emitting linearly polarized light and in a direction orthogonal to the transmission axis direction.
  • the direction in which linearly polarized light is emitted is defined as the transmission axis direction
  • the direction in which linearly polarized light is emitted is defined as the absorption axis direction
  • the polarizing film in which the polarized light in the blocking direction is reflected is not excluded. ..
  • the protective film is for protecting the polarizing film.
  • a film widely used in the technical field of polarizing plates is used for the purpose of obtaining a polarizing plate having appropriate mechanical strength.
  • a cellulose ester film such as a triacetyl cellulose (TAC) film; a cyclic olefin film; a polyester film such as a polyethylene terephthalate (PET) film: a (meth) acrylic film such as a polymethyl methacrylate (PMMA) film.
  • PET polyethylene terephthalate
  • PMMA polymethyl methacrylate
  • an additive widely used in the technical field of the polarizing plate may be contained in the protective film.
  • the phase difference of the protective film used for the linear polarizing plate is preferably small.
  • Re (550) is preferably 10 nm or less, and particularly preferably 5 nm or less.
  • the light source 2 is, for example, linear light such as laser light (including one that approximates linear light).
  • the light emitted by the light source 2 is unpolarized, passes through the first linear polarizing plate 3 to be polarized in a predetermined direction, and further passes through the retardation film 7A to be circularly polarized light. That is, unpolarized light passes through the first linear polarizing plate 3 and the retardation film 7A, resulting in circularly polarized light.
  • the retardation filter 4 includes a retardation film 7B.
  • the in-plane retardation value at a wavelength of 550 nm and the in-plane retardation value of the retardation film 7A to be inspected at a wavelength of 550 nm are 250 nm to 300 nm in total.
  • the total is preferably 260 nm to 290 nm, more preferably 270 nm to 280 nm, and even more preferably ⁇ / 2.
  • " ⁇ " is a measurement wavelength (here, 550 nm).
  • the optical defect is determined from the luminance (brightness) information ⁇ L *, it is preferable to use a film having the same configuration as that of the object 10 to be inspected for the retardation filter 4. Further, when the optical defect is determined from the color difference information ⁇ E *, it is preferable to use a film having a wavelength dispersibility opposite to that of the object 10 to be inspected for the phase difference filter 4. Further, the retardation filter 4 is arranged so that the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are parallel to each other.
  • the retardation filter 4 is adjusted so that the polarization axis of linearly polarized light is always rotated in the same direction together with the retardation film 7A in the object 10 to be inspected. Will be done.
  • the retardation film 7A and the retardation filter 4 act as a ⁇ / 2 plate.
  • the phase difference filter 4 may further include a positive C plate.
  • the positive C plate may be provided on the surface facing the retardation film 7A, or may be provided on the surface opposite to the retardation film 7A.
  • the inspection area can be expanded by using the positive C plate.
  • the retardation value (Rth (550)) in the thickness direction of the positive C plate may be appropriately selected according to the retardation value in the thickness direction of the retardation film 7A to be inspected.
  • the retardation film 7A is a ⁇ / 4 plate. In the case of, the effect can be easily obtained by using a phase difference value (Rth (550)) in the thickness direction of ⁇ 50 nm to ⁇ 300 nm.
  • the retardation filter 4 may include a retardation film 7B and a base film 8B on which the retardation film 7B is laminated.
  • a film having an in-plane retardation value (Re (550)) of substantially zero is used so as not to impair the optical characteristics of the retardation film 7B.
  • the in-plane phase difference is substantially zero, it means that the in-plane phase difference value (Re (550)) is 3 nm or less.
  • Re (550) in-plane retardation value (Re (550)) and the thickness direction retardation value (Rth (550)) at a wavelength of 550 nm
  • Re (550) of this piece is measured three times, and the average value of Re (550) is obtained.
  • One piece of Re (550) can be measured at a measurement temperature of room temperature (23 ° C.) using a phase difference measuring device KOBRA-WPR (manufactured by Oji Measuring Instruments Co., Ltd.).
  • the second linear polarizing plate 5 is a film into which light that has passed through the retardation filter 4 is incident, and its configuration and material are the same as those of the first linear polarizing plate 3.
  • the inspection device 1A when the second linear polarizing plate 5 is viewed from the direction of the optical axis 9 of the light from the light source 2 toward the camera 6 as shown in FIGS. 2 (A) and 2 (B).
  • the angles ⁇ 1 and ⁇ 2 both refer to angles or right angles on the acute angle ( ⁇ 1 ⁇ 90 °, ⁇ 2 ⁇ 90 °) side.
  • FIG. 2 (B)
  • a positive C plate may be arranged between the first linear polarizing plate 3 and the base film 8A.
  • the retardation value (Rth (550)) in the thickness direction of the positive C plate may be appropriately selected according to the retardation value in the thickness direction of the base film 8A.
  • the retardation value in the thickness direction of the base film 8A For example, the retardation value in the thickness direction of the base film 8A. The effect can be easily obtained by setting the phase difference value in the thickness direction to about 1/3 to 2/3 of (Rth (550)).
  • the inspection device 1A of the present embodiment in order to observe the light that has passed through the first linear polarizing plate 3, the object to be inspected 10, the retardation filter 4, and the second linear polarizing plate 5, the light is on the optical axis 9.
  • the camera (detecting means) 6 is arranged at a position on both sides of the retardation filter 4 opposite to the side where the light source 2 is located.
  • the camera 6 is, for example, a CCD camera.
  • the camera 6 is automatically detected by image processing analysis in which the CCD camera and the image processing device are combined, whereby the object 10 to be inspected can be inspected.
  • a human may visually observe the second linear polarizing plate 5 instead of the camera 6.
  • the inspection method using the inspection device 1A is as follows. First, in the inside of the inspection device 1A, the object 10 to be inspected is arranged between the first linear polarizing plate 3 and the retardation filter 4. At this time, the object 10 to be inspected has the base film 8A side facing the first linear polarizing plate 3 side, and the slow axis of the base film 8A and the polarizing axis of the first linear polarizing plate 3. Arrange so that the (transmission axis) is substantially orthogonal to or substantially parallel to each other. Then, the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are made parallel to each other, and further, as shown in FIG.
  • the optical axis of light from the light source 2 toward the camera 6 When viewed from the direction of 9, the angle ⁇ 1 formed by the transmission axis p of the first linear polarizing plate 3 and the slow axis q of the retardation film 7A, and the absorption axis r and position of the second linear polarizing plate 5.
  • the retarding film 7A is arranged so that the angle ⁇ 2 formed by the slow axis q and the retarding axis q are substantially the same as each other.
  • the transmission axis p of the first linear polarizing plate 3 and the absorption axis r of the second linear polarizing plate 5 are arranged so as to be substantially line symmetric. To do. Since the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are parallel to each other, the first straight line when viewed from the direction of the optical axis 9 of the light from the light source 2 to the camera 6.
  • the angle formed by the transmission axis p of the polarizing plate 3 and the slow axis of the retardation filter 4 and the angle formed by the absorption axis r of the second linear polarizing plate 5 and the slow axis of the retardation filter 4 are approximately mutually exclusive. It is the same.
  • Light is emitted from the light source 2 toward the first linear polarizing plate 3.
  • the light emitted by the light source 2 is incident on the first linear polarizing plate 3, where the unpolarized light is converted into linearly polarized light.
  • the linearly polarized light is incident on the object 10 to be inspected from the base film 8A side.
  • the linearly polarized light that has passed through the base film 8A passes through the retardation film 7A and becomes circularly polarized light. This circularly polarized light is incident on the retardation filter 4 from the retardation film 7B side.
  • the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are substantially parallel to each other, and the in-plane retardation value of the retardation film 7A at a wavelength of 550 nm and the phase difference. Since the total of the in-plane retardation value at the wavelength of 550 nm of the filter 4 is 250 nm to 300 nm, the light passing through the retardation filter 4 is linearly polarized light, and the linearly polarized light is immediately before incident on the object to be inspected. This means that a phase difference of about ⁇ / 2 is generated as compared with the linearly polarized light of.
  • the second linear polarizing plate 5 has an angle ⁇ 1 formed by the transmission axis of the first linear polarizing plate 3 and the slow axis of the retardation film 7A when viewed from the direction of the optical axis 9, and a second. Since the angle ⁇ 2 formed by the absorption axis of the linear polarizing plate 5 and the slow axis of the retardation film 7A is arranged to be substantially the same as each other, it passes through the retardation filter 4 and returns to linearly polarized light. The light is blocked by the second linear polarizing plate 5. In this inspection, when there is no defect in the retardation film 7A in the object to be inspected 10, the entire surface of the second linear polarizing plate 5 looks uniform black when observed by the camera 6.
  • the retardation film 7A in the object 10 to be inspected has a defect
  • the light passing through the defect portion does not become the expected linearly polarized light but becomes elliptically polarized light. Therefore, the second linear polarizing plate 5 cannot perform regular blocking and light leaks, and the defective portion is observed as a bright spot in the observation by the camera 6.
  • the base film 8A has a phase difference of "the in-plane retardation value at a wavelength of 550 nm is 50 nm or more"
  • the polarized state of the light passing through the first linear polarizing plate 3 is the base film 8A. Can be disturbed by.
  • the transmission axes of the first linear polarizing plate 3 are arranged so as to be substantially orthogonal to or substantially parallel to the slow axis of the base film 8A having a phase difference. Therefore, the polarization state of the light that has passed through the first linear polarizing plate 3 is not disturbed by the base film 8A.
  • the assembled optical system functions as intended, and when the retardation film 7A has a defect, the defect can be appropriately recognized in the observation field of view.
  • the in-plane retardation value of the base film 8A is 50 nm or more
  • the light passing through the first linear polarizing plate 3 is circularly polarized (elliptical polarized light) due to the retardation of the base film 8A.
  • the amount of light leaking from the second linear polarizing plate 5 increased, which hindered the inspection. Therefore, according to the inspection method of the present embodiment, it is possible to easily determine the presence or absence of defects in the retardation film while suppressing the influence of the in-plane retardation of the base film 8A.
  • the inspection method of the present embodiment can be continuously performed on the same production line as the step of continuously forming the retardation film 7A on the base film 8A. it can.
  • the inspection system 100 shown in FIG. 3 is an orientation angle measuring device that determines the direction of the slow axis (orientation angle) of the base film 8A before the retardation film 7A is formed, in addition to the inspection device 1A described above.
  • the first straight line so that the slow axis of the base film 8A obtained by the orientation angle measuring device 12 and the transmission axis of the first linear polarizing plate 3 are substantially orthogonal to each other or substantially parallel to each other.
  • the object 10 to be inspected passes through the optical axis 9 of the inspection device 1A while being conveyed, and is inspected for defects. Then, the inspected object 10 that has been inspected is wound up.
  • the width of the base film 8A may be, for example, 0.5 to 2.0 m or 1.0 to 1.5 m.
  • a plurality of inspection devices 1A are arranged in the width direction (direction perpendicular to the transport direction) of the object 10 to be inspected.
  • the inspection device 1A is preferably arranged at 5 to 20 locations along the width direction of the object to be inspected 10. In FIG. 4, five inspection devices 1A are arranged.
  • the direction of the slow axis of the base film 8A is measured by the orientation angle measuring device 12 while transporting the long base film 8A.
  • the direction of the slow phase axis changes in the width direction as shown in FIG.
  • the arrow indicates the direction of the slow axis at that portion. Therefore, the measurement by the orientation angle measuring device 12 is performed at a plurality of locations extending in the width direction of the base film 8A.
  • the orientation angle measuring device 12 provides the measured information on the slow-phase axis to the angle adjusting mechanism 14.
  • a polymerizable liquid crystal compound solution is applied onto the base film 8A with the coating machine 16 to form a coating film 7a, and a dryer arranged on the downstream side of the coating machine 16
  • the coating film 7a is dried at 18.
  • the coated polymerizable liquid crystal compound is oriented on the base film 8A and cured by drying and polymerization to form a retardation film 7A.
  • the dried film is the object 10 to be inspected, and is subjected to inspection by the inspection device 1A arranged on the downstream side of the transport.
  • the angle adjusting mechanism 14 rotates the first linear polarizing plate 3 based on the information in the slow axis direction of the base film 8A provided by the orientation angle measuring instrument 12, and transmits the first linear polarizing plate 3.
  • the axis is made to be substantially orthogonal or substantially parallel to the slow axis of the base film 8A.
  • the retardation filter 4 and the second linear polarizing plate 5 are also rotated so as to have the above-mentioned predetermined relationship.
  • An inspection area A (see FIG. 4) is assigned to each of the plurality of inspection devices 1A arranged in the width direction of the object 10 to be inspected, and the object 10 to be inspected is inspected over the entire area in the width direction. ..
  • the angle adjusting mechanism 14 faces the transmission axis of the first linear polarizing plate 3 for each inspection region A according to the slow axis of the base film 8A changing in the width direction. It will be in a different direction.
  • the inspection area A shown in FIG. 5 indicates a portion on the base film 8A corresponding to the inspection area A shown in FIG.
  • the retardation film 7A can be continuously and efficiently formed and inspected in the transport direction of the base film 8A, so that the production and inspection of the inspected object 10 can be made more efficient. Will be done. Further, in the inspection system 100, since a plurality of inspection devices 1A are arranged in the width direction of the object 10 to be inspected, even if the directions of the slow axes of the base film 8A are different in the width direction, the individual inspection devices are arranged. The relationship between the transmission axis of the first linear polarizing plate 3 in 1A and the slow axis in the inspection region A of the base film 8A can be adjusted to a predetermined relationship. That is, it is possible to perform an inspection in which the influence of the in-plane retardation of the base film 8A is suppressed at any position in the width direction of the base film 8A.
  • FIG. 6 depicts a state in which the object to be inspected 10 to be inspected is arranged between the first linear polarizing plate 3 and the retardation filter 4.
  • the slow axis of the base film 8A and the transmission axis of the second linear polarizing plate 5 are substantially orthogonal to each other or substantially parallel to each other. Arrange so that
  • the presence or absence of defects in the retardation film 7A can be easily inspected by the same principle as in the first embodiment.
  • the present invention can be used for an inspection for determining the presence or absence of defects in the retardation film.
  • 1A, 1B ... Inspection device 2 ... Light source, 3 ... First linear polarizing plate, 4 ... Phase difference filter, 5 ... Second linear polarizing plate, 6 ... Camera (detection means), 7A, 7B ... Phase difference film , 7a ... Coating film, 8A, 8B ... Base film, 9 ... Optical axis, 10 ... Inspected object, 12 ... Orientation angle measuring instrument, 14 ... Angle adjustment mechanism, 16 ... Coating machine, 18 ... Dryer, 100 ... Inspection system, A ... Inspection region, p ... Transmission axis of the first linear polarizing plate, q ... Slow axis of the retardation film 7A, r ... Absorption axis of the second linear polarizing plate.

Abstract

In this inspection method, light is emitted onto an object 10 under inspection comprising a base film 8A having an in-plane retardation value of 50 nm or more for a wavelength of 550 nm and a retardation film 7A that is formed on one side of the base film 8A and comprises a cured polymerizable liquid crystal compound, and a determination is made as to whether there is a defect on the retardation film. A first linear polarization plate 3, the object 10 under inspection, a retardation filter 4, and a second linear polarization plate 5 are arranged so as to be aligned in the order listed. The slow axis of the base film and the transmission axis of the first linear polarization plate or second linear polarization plate are roughly orthogonal or roughly parallel to each other. The slow axis of the retardation film and the slow axis of the retardation filter are roughly parallel to each other. When viewed from the optical axis direction of the light, the transmission axis of the first linear polarization plate and the absorption axis of the second linear polarization plate are roughly linearly symmetrical, with the slow axis of the retardation film as the axis of symmetry.

Description

検査方法、検査装置、及び検査システムInspection method, inspection equipment, and inspection system
　本発明は、検査方法、検査装置、及び検査システムに関する。 The present invention relates to an inspection method, an inspection device, and an inspection system.
　位相差膜は、直線偏光を円偏光や楕円偏光に変換したり、逆に円偏光や楕円偏光を直線偏光に変換したりできることから、この位相差膜と直線偏光板とを組み合わせた（楕）円偏光板が、有機ＥＬ表示装置や反射型液晶表示装置に適用されている。位相差膜の中でも重合性液晶化合物を配向及び硬化させることで得られる位相差膜は極めて薄膜のものとなることから、薄型の表示装置を製造するうえで注目されてきている（例えば、特許文献１参照）。 Since the retardation film can convert linearly polarized light into circularly polarized light or elliptically polarized light, and conversely, can convert circularly polarized light or elliptically polarized light into linearly polarized light, this retardation film and linearly polarized light are combined (elbow). Circularly polarized light is applied to an organic EL display device and a reflective liquid crystal display device. Among the retardation films, the retardation film obtained by orienting and curing a polymerizable liquid crystal compound is an extremely thin film, and has been attracting attention in manufacturing a thin display device (for example, patent documents). 1).
　このような位相差膜を製造する方法としては、通常、重合性液晶化合物を含む液状組成物を長尺状の基材フィルムに塗工して薄膜を形成し、その薄膜中の重合性液晶化合物を所望の方向に配向させた後、活性エネルギー線を照射する。これにより、配向した重合性液晶化合物が硬化し位相差膜となる。なお、重合性液晶化合物を配向させるにあたっては、液状組成物を基材フィルムに塗工する前に、基材フィルム上に配向膜を形成する場合もある。 As a method for producing such a retardation film, usually, a liquid composition containing a polymerizable liquid crystal compound is applied to a long base film to form a thin film, and the polymerizable liquid crystal compound in the thin film is formed. Is oriented in the desired direction and then irradiated with active energy rays. As a result, the oriented polymerizable liquid crystal compound is cured to form a retardation film. When aligning the polymerizable liquid crystal compound, an alignment film may be formed on the base film before the liquid composition is applied to the base film.
特開２００６－５８５４６号公報Japanese Unexamined Patent Publication No. 2006-58546
　この製造方法では、基材フィルム上又は配向膜状にゴミ等があると、そのゴミの部分で重合性液晶化合物の配向が乱れて欠陥が生じることがある。そして、基材フィルムが面内位相差を有するものであると、当該基材フィルム上に形成した位相差膜の欠陥の有無を光学的手法で検査することが困難になりやすい。市場から安価に入手できる基材フィルムは一般に延伸して製造されていることから、安価な基材フィルムは上記方法で製造した位相差膜の検査には使いにくいという実態がある。 In this production method, if there is dust or the like on the base film or in the form of an alignment film, the orientation of the polymerizable liquid crystal compound may be disturbed at the dust portion and defects may occur. If the base film has an in-plane retardation, it tends to be difficult to inspect the presence or absence of defects in the retardation film formed on the base film by an optical method. Since the base film that can be inexpensively obtained from the market is generally produced by stretching, the fact is that the inexpensive base film is difficult to use for the inspection of the retardation film produced by the above method.
　そこで本発明は、基材フィルムが有する面内位相差の影響を抑制しながら、重合性液晶化合物の硬化物からなる位相差膜の欠陥の有無の検査をすることができる検査方法、検査装置及び検査システムを提供することを目的とする。 Therefore, the present invention provides an inspection method, an inspection apparatus, and an inspection apparatus capable of inspecting the presence or absence of defects in a retardation film made of a cured product of a polymerizable liquid crystal compound while suppressing the influence of the in-plane retardation of the base film. The purpose is to provide an inspection system.
　本発明は、波長５５０ｎｍにおける面内位相差値が５０ｎｍ以上である基材フィルムと、基材フィルムの片面に形成された重合性液晶化合物の硬化物からなる位相差膜とを備えるフィルム状の被検査物に光を入射して位相差膜の欠陥の有無を判断する検査方法であって、第１の直線偏光板と、被検査物と、位相差フィルタと、第２の直線偏光板と、をこの順に並ぶように配置し、被検査物は、基材フィルム側の面が第１の直線偏光板側を向いており、基材フィルムの遅相軸と、第１の直線偏光板又は第２の直線偏光板の透過軸とは互いに略直交しており又は略平行であり、位相差膜の遅相軸と、位相差フィルタの遅相軸とは互いに略平行であり、位相差膜の波長５５０ｎｍにおける面内位相差値は、３００ｎｍ以下であり、位相差膜の波長５５０ｎｍにおける面内位相差値と、位相差フィルタの波長５５０ｎｍにおける面内位相差値との合計が、２５０ｎｍ～３００ｎｍであり、光の光軸方向から見た場合に、位相差膜の遅相軸を対称軸として、第１の直線偏光板の透過軸と第２の直線偏光板の吸収軸が略線対称となるように配置し、第１の直線偏光板側又は第２の直線偏光板側のいずれか一方側から、光軸が被検査物上の所定の検査領域を通過するように光を入射し、その他方側から第２の直線偏光板又は第１の直線偏光板を観察する、検査方法を提供する。 The present invention is a film-like substrate comprising a base film having an in-plane retardation value of 50 nm or more at a wavelength of 550 nm and a retardation film made of a cured product of a polymerizable liquid crystal compound formed on one side of the base film. This is an inspection method in which light is incident on an inspection object to determine the presence or absence of defects in the retardation film, and the first linear polarizing plate, the object to be inspected, the retardation filter, the second linear polarizing plate, and the like. Are arranged in this order, and in the object to be inspected, the surface on the base film side faces the first linear polarizing plate side, and the slow axis of the base film and the first linear polarizing plate or the first linear polarizing plate or the first The transmission axes of the linearly polarizing plate No. 2 are substantially orthogonal to or substantially parallel to each other, and the slow axis of the retardation film and the slow axis of the retardation filter are substantially parallel to each other, and the retardation film of the retardation film. The in-plane retardation value at a wavelength of 550 nm is 300 nm or less, and the total of the in-plane retardation value at a wavelength of 550 nm of the retardation film and the in-plane retardation value at a wavelength of 550 nm of the retardation filter is 250 nm to 300 nm. When viewed from the optical axis direction of light, the transmission axis of the first linearly polarized light and the absorption axis of the second linearly polarized light are substantially linearly symmetric with the slow axis of the retardation film as the axis of symmetry. Injecting light from either the first linear polarizing plate side or the second linear polarizing plate side so that the optical axis passes through a predetermined inspection region on the object to be inspected. Provided is an inspection method for observing a second linear polarizing plate or a first linear polarizing plate from the side.
　この検査方法では、位相差を有する基材フィルムの遅相軸に対して第１の直線偏光板又は第２の直線偏光板の透過軸を互いに略直交するように又は略平行となるように配置するので、直線偏光板を通過した光の偏光状態が基材フィルムによって乱されることがない。
すなわち、組んだ光学系が意図したとおりに機能し、位相差膜に欠陥があった場合に観察視野においてその欠陥を適切に認識することができる。また、この検査方法では、位相差膜の波長５５０ｎｍにおける面内位相差値と位相差フィルタの波長５５０ｎｍにおける面内位相差値との合計が２５０ｎｍ～３００ｎｍであり、且つ、光の光軸方向から見た場合に、位相差膜の遅相軸を対称軸として、第１の直線偏光板の透過軸と第２の直線偏光板の吸収軸が略線対称となるように配置するので、位相差膜及び位相差フィルタを通過した直線偏光はその前後で約λ/２の位相差が生じることになる。これにより、観察視野において位相差膜の正常部分と欠陥部分との輝度差が大きくなる。従って、この検査方法によれば、基材フィルムが有する面内位相差の影響を抑制しながら位相差膜の欠陥の有無を容易に判断することができる。 In this inspection method, the transmission axes of the first linear polarizing plate or the second linear polarizing plate are arranged so as to be substantially orthogonal to or substantially parallel to the slow axis of the substrate film having a retardation. Therefore, the polarization state of the light that has passed through the linear polarizing plate is not disturbed by the base film.
That is, the assembled optical system functions as intended, and when there is a defect in the retardation film, the defect can be appropriately recognized in the observation field of view. Further, in this inspection method, the total of the in-plane retardation value at the wavelength of 550 nm of the retardation film and the in-plane retardation value at the wavelength of 550 nm of the retardation filter is 250 nm to 300 nm, and from the optical axis direction of light. When viewed, the slow axis of the retardation film is set as the axis of symmetry, and the transmission axis of the first linearly polarizing plate and the absorption axis of the second linearly polarizing plate are arranged so as to be substantially line-symmetrical. The linearly polarized light that has passed through the film and the phase difference filter will have a phase difference of about λ / 2 before and after that. As a result, the difference in brightness between the normal portion and the defective portion of the retardation film becomes large in the observation field of view. Therefore, according to this inspection method, it is possible to easily determine the presence or absence of defects in the retardation film while suppressing the influence of the in-plane retardation of the base film.
　この検査方法では、位相差膜が形成される前の基材フィルムを対象として、配向角測定器を用いて基材フィルムの遅相軸の方向を予め求める工程を有していてもよい。基材フィルムの遅相軸の方向が不明である場合は、予めこれを求めておくことで、第１の直線偏光板又は第２の直線偏光板の透過軸を基材フィルムの遅相軸と互いに略直交するように又は略平行となるように配置することができる。 In this inspection method, there may be a step of determining the direction of the slow axis of the base film in advance using an orientation angle measuring device for the base film before the retardation film is formed. If the direction of the slow axis of the base film is unknown, by obtaining this in advance, the transmission axis of the first linear polarizing plate or the second linear polarizing plate can be used as the slow axis of the base film. They can be arranged so as to be substantially orthogonal to each other or substantially parallel to each other.
　そしてこのとき、配向角測定器により基材フィルムの遅相軸を求めた後に、基材フィルムの片面に、重合性液晶化合物を含む液状組成物を塗工して基材フィルムの表面上に重合性液晶化合物を含む塗工膜を形成し、塗工膜に含まれる重合性液晶化合物を配向及び硬化させて位相差膜を形成する工程を有していてもよい。これにより、位相差膜の製造が効率化される。 At this time, after determining the slow axis of the base film with an orientation angle measuring device, a liquid composition containing a polymerizable liquid crystal compound is applied to one side of the base film and polymerized on the surface of the base film. It may have a step of forming a coating film containing a property liquid crystal compound and orienting and curing the polymerizable liquid crystal compound contained in the coating film to form a retardation film. This makes the production of the retardation film more efficient.
　また、本発明の検査方法では、被検査物を、第１の直線偏光板と位相差フィルタとの間で被検査物の長さ方向に搬送させながら、長さ方向に連続して検査を行ってもよい。これにより、被検査物の検査が効率化される。 Further, in the inspection method of the present invention, the object to be inspected is continuously inspected in the length direction while being conveyed between the first linear polarizing plate and the retardation filter in the length direction of the object to be inspected. You may. This makes the inspection of the object to be inspected more efficient.
　また、本発明の検査方法では、検査領域を、被検査物の幅方向に複数箇所設けてもよい。基材フィルムは一般に、少なくとも一方向に延伸することで製造されているため、幅方向において遅相軸の方向が異なっていることが多い。したがって、被検査物の幅方向に亘って検査領域を区分しそれぞれの検査領域において当該検査を行うことで、幅方向の各部において、基材フィルムが有する面内位相差の影響を抑制した検査を行うことができる。 Further, in the inspection method of the present invention, a plurality of inspection areas may be provided in the width direction of the object to be inspected. Since the base film is generally produced by stretching in at least one direction, the direction of the slow axis is often different in the width direction. Therefore, by dividing the inspection area in the width direction of the object to be inspected and performing the inspection in each inspection area, the inspection in which the influence of the in-plane retardation of the base film is suppressed in each part in the width direction can be performed. It can be carried out.
　また、本発明は、波長５５０ｎｍにおける面内位相差値が５０ｎｍ以上である基材フィルムと、基材フィルムの片面に形成された重合性液晶化合物の硬化物からなる位相差膜とを備えるフィルム状の被検査物に光を入射して位相差膜の欠陥の有無を判断する検査装置であって、被検査物が配置される場所を挟むようにして配置された第１の直線偏光板及び位相差フィルタと、位相差フィルタに関して被検査物が配置される場所とは反対側の領域に配置された第２の直線偏光板と、第１の直線偏光板又は第２の直線偏光板に関して被検査物が配置される場所とは反対側の領域に配置された光源と、を備え、第１の直線偏光板又は第２の直線偏光板は、その透過軸が基材フィルムの遅相軸と互いに略直交するように又は略平行となるように配置されており、位相差フィルタは、その遅相軸が位相差膜の遅相軸と互いに略平行となるように配置されており、位相差フィルタの波長５５０ｎｍにおける面内位相差値は、位相差膜の波長５５０ｎｍにおける面内位相差値との合計が２５０ｎｍ～３００ｎｍとなる値であり、光の光軸方向から見た場合に、位相差膜の遅相軸を対称軸として、第１の直線偏光板の透過軸と第２の直線偏光板の吸収軸が略線対称となるように配置されており、光源は、その光軸上に第１の直線偏光板、被検査物上の所定の検査領域、位相差フィルタ、及び、第２の直線偏光板が並ぶ位置に配置されている、検査装置を提供する。 Further, the present invention is in the form of a film including a base film having an in-plane retardation value of 50 nm or more at a wavelength of 550 nm and a retardation film made of a cured product of a polymerizable liquid crystal compound formed on one side of the base film. A first linear polarizing plate and a retardation filter arranged so as to sandwich a place where the object to be inspected is placed, which is an inspection device for determining the presence or absence of defects in the retardation film by injecting light into the object to be inspected. And the second linear polarizing plate arranged in the region opposite to the place where the inspected object is arranged with respect to the retardation filter, and the inspected object with respect to the first linear polarizing plate or the second linear polarizing plate. A light source arranged in a region opposite to the place where it is arranged is provided, and the transmission axis of the first linear polarizing plate or the second linear polarizing plate is substantially orthogonal to the slow axis of the base film. The retardation filter is arranged so that its slow axis is substantially parallel to the slow axis of the retardation film, and the wavelength of the retardation filter is substantially parallel to each other. The in-plane retardation value at 550 nm is a value at which the total of the in-plane retardation value at the wavelength of 550 nm of the retardation film is 250 nm to 300 nm, and the retardation of the retardation film is delayed when viewed from the optical axis direction of light. With the phase axis as the axis of symmetry, the transmission axis of the first linearly polarizing plate and the absorption axis of the second linearly polarizing plate are arranged so as to be substantially linearly symmetric, and the light source is the first on the optical axis. Provided is an inspection apparatus in which a linear polarizing plate, a predetermined inspection region on an object to be inspected, a retardation filter, and a second linear polarizing plate are arranged at a lined position.
　この検査装置では、位相差を有する基材フィルムの遅相軸に対して第１の直線偏光板又は第２の直線偏光板の透過軸を互いに略直交するように又は略平行となるように配置するので、直線偏光板を通過した光の偏光状態が基材フィルムによって乱されることがない。
すなわち、組んだ光学系が意図したとおりに機能し、位相差膜に欠陥があった場合に観察視野においてその欠陥を適切に認識することができる。また、この検査装置では、位相差膜の波長５５０ｎｍにおける面内位相差値と位相差フィルタの波長５５０ｎｍにおける面内位相差値との合計が２５０ｎｍ～３００ｎｍであり、且つ、光の光軸方向から見た場合に、位相差膜の遅相軸を対称軸として、第１の直線偏光板の透過軸と第２の直線偏光板の吸収軸が略線対称となるように配置するので、位相差膜及び位相差フィルタを通過した直線偏光はその前後で約λ/２の位相差が生じることになる。これにより、観察視野において位相差膜の正常部分と欠陥部分との輝度差が大きくなる。従って、この検査装置によれば、基材フィルムが有する面内位相差の影響を抑制しながら位相差膜の欠陥の有無を容易に判断することができる。 In this inspection device, the transmission axes of the first linear polarizing plate or the second linear polarizing plate are arranged so as to be substantially orthogonal to or substantially parallel to the slow axis of the substrate film having a retardation. Therefore, the polarization state of the light that has passed through the linear polarizing plate is not disturbed by the base film.
That is, the assembled optical system functions as intended, and when there is a defect in the retardation film, the defect can be appropriately recognized in the observation field of view. Further, in this inspection device, the total of the in-plane retardation value at the wavelength of 550 nm of the retardation film and the in-plane retardation value at the wavelength of 550 nm of the retardation filter is 250 nm to 300 nm, and from the optical axis direction of light. When viewed, the slow axis of the retardation film is set as the axis of symmetry, and the transmission axis of the first linearly polarizing plate and the absorption axis of the second linearly polarizing plate are arranged so as to be substantially line-symmetrical. The linearly polarized light that has passed through the film and the phase difference filter will have a phase difference of about λ / 2 before and after that. As a result, the difference in brightness between the normal portion and the defective portion of the retardation film becomes large in the observation field of view. Therefore, according to this inspection apparatus, it is possible to easily determine the presence or absence of defects in the retardation film while suppressing the influence of the in-plane retardation of the base film.
　また、本発明は、上記の検査装置と、位相差膜が形成される前の基材フィルムの遅相軸を求める配向角測定器と、配向角測定器で求められた基材フィルムの遅相軸と第１の直線偏光板の透過軸とが互いに略直交するように又は略平行となるように第１の直線偏光板の角度を調節する角度調整機構とを備える、検査システムを提供する。基材フィルムの遅相軸の方向が不明である場合は、予めこれを求めておくことで、第１の直線偏光板又は第２の直線偏光板の透過軸を基材フィルムの遅相軸と互いに略直交するように又は略平行となるように配置することができる。また、角度調節機構を備えることで、その角度調整を自動化することができる。 Further, in the present invention, the above-mentioned inspection device, an alignment angle measuring device for determining the slow axis of the base film before the retardation film is formed, and a slow phase of the base film obtained by the alignment angle measuring device. Provided is an inspection system including an angle adjusting mechanism for adjusting the angle of the first linear polarizing plate so that the axis and the transmission axis of the first linear polarizing plate are substantially orthogonal to each other or substantially parallel to each other. If the direction of the slow axis of the base film is unknown, by obtaining this in advance, the transmission axis of the first linear polarizing plate or the second linear polarizing plate can be used as the slow axis of the base film. They can be arranged so as to be substantially orthogonal to each other or substantially parallel to each other. Further, by providing the angle adjustment mechanism, the angle adjustment can be automated.
　本発明によれば、基材フィルムが有する面内位相差の影響を抑制しながら、重合性液晶化合物の硬化物からなる位相差膜の欠陥の有無の検査をすることができる検査方法、検査装置及び検査システムを提供することができる。 According to the present invention, an inspection method and an inspection apparatus capable of inspecting the presence or absence of defects in a retardation film made of a cured product of a polymerizable liquid crystal compound while suppressing the influence of the in-plane retardation of the base film. And an inspection system can be provided.
第１の実施形態の検査装置を示す図である。It is a figure which shows the inspection apparatus of 1st Embodiment. （Ａ）は、第１の実施形態における第１の直線偏光板の透過軸及び第２の直線偏光板の吸収軸と位相差膜の遅相軸との関係を示す図である。（Ｂ）は、（Ａ）を光軸側から見た図である。FIG. (A) is a diagram showing the relationship between the transmission axis of the first linear polarizing plate and the absorption axis of the second linear polarizing plate and the slow axis of the retardation film in the first embodiment. (B) is a view of (A) viewed from the optical axis side. 第１の実施形態の検査システムを示す図である。It is a figure which shows the inspection system of 1st Embodiment. 第１の実施形態の検査システムにおける複数の検査装置の配置を示す部分斜視図である。It is a partial perspective view which shows the arrangement of a plurality of inspection apparatus in the inspection system of 1st Embodiment. 基材フィルムの遅相軸の様子を示す平面図である。It is a top view which shows the state of the slow-phase axis of a base film. 第２の実施形態の検査装置を示す図である。It is a figure which shows the inspection apparatus of 2nd Embodiment.
　以下、本発明の好適な実施形態について、図面を参照しながら詳細に説明する。なお、各図において同一部分又は相当部分には同一符号を付し、重複する説明は省略する。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.
（用語および記号の定義）
　本明細書における用語および記号の定義は下記の通りである。
（１）屈折率（ｎｘ、ｎｙ、ｎｚ）
　「ｎｘ」は面内の屈折率が最大となる方向（すなわち、遅相軸方向）の屈折率であり、「ｎｙ」は面内で遅相軸と直交する方向、「ｎｚ」は厚み方向の屈折率である。
（２）面内位相差値
　面内位相差値（Ｒｅ（λ））は、２３℃、波長λ（ｎｍ）におけるフィルムの面内の位相差値をいう。Ｒｅ（λ）は、フィルムの厚みをｄ（ｎｍ）としたとき、Ｒｅ（λ）＝（ｎｘ－ｎｙ）×ｄによって求められる。
（３）厚み方向の位相差値
　厚み方向の位相差値（Ｒｔｈ（λ））は、２３℃、波長λ（ｎｍ）におけるフィルムの厚み方向の位相差値をいう。Ｒｔｈ（λ）は、フィルムの厚みをｄ（ｎｍ）としたとき、Ｒｔｈ（λ）＝（（ｎｘ＋ｎｙ）／２－ｎｚ）×ｄによって求められる。 (Definition of terms and symbols)
Definitions of terms and symbols herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), "ny" is the direction orthogonal to the slow-phase axis in the in-plane, and "nz" is the thickness direction. Refractive index.
(2) In-plane retardation value The in-plane retardation value (Re (λ)) refers to the in-plane retardation value of the film at 23 ° C. and a wavelength of λ (nm). Re (λ) is obtained by Re (λ) = (nx−ny) × d, where d (nm) is the thickness of the film.
(3) Phase difference value in the thickness direction The phase difference value in the thickness direction (Rth (λ)) refers to the phase difference value in the thickness direction of the film at 23 ° C. and a wavelength of λ (nm). Rth (λ) is obtained by Rth (λ) = ((nx + ny) / 2-nz) × d, where d (nm) is the thickness of the film.
＜第１の実施形態＞
（検査装置と被検査物）
　本実施形態の検査装置は、位相差膜の表面欠陥の有無を検査するものである。図１に示されているとおり、検査装置１Ａは、光源２、第１の直線偏光板３、位相差フィルタ４、第２の直線偏光板５、及び、カメラ（検出手段）６がこの順に配置されてなるものである。検査装置１Ａは、第１の直線偏光板３と位相差フィルタ４との間に、検査対象である被検査物１０を配置する場所が用意されており、図１では、被検査物１０をそこに配置した様子を描いている。 <First Embodiment>
(Inspection device and object to be inspected)
The inspection device of the present embodiment inspects the presence or absence of surface defects of the retardation film. As shown in FIG. 1, in the inspection device 1A, the light source 2, the first linear polarizing plate 3, the retardation filter 4, the second linear polarizing plate 5, and the camera (detecting means) 6 are arranged in this order. It is something that has been done. The inspection device 1A is provided with a place for arranging the inspected object 10 to be inspected between the first linear polarizing plate 3 and the retardation filter 4, and in FIG. 1, the inspected object 10 is placed there. It depicts how it was placed in.
　はじめに、検査対象であるフィルム状の被検査物１０について説明する。被検査物１０は、検査対象の本体である位相差膜７Ａと、位相差膜７Ａが片面に積層された基材フィルム８Ａとを備えている。位相差膜７Ａの１つの例としては、直線偏光板と組み合わせて表示装置、例えば液晶表示装置や有機ＥＬ表示装置に円偏光板として用いられるものである。なお、本明細書において「円偏光板」とは、円偏光板及び楕円偏光板を含むものとする。また、「円偏光」は、円偏光と楕円偏光を含むものとする。 First, the film-shaped object 10 to be inspected will be described. The object 10 to be inspected includes a retardation film 7A which is a main body to be inspected, and a base film 8A in which the retardation film 7A is laminated on one side. As one example of the retardation film 7A, it is used as a circular polarizing plate in a display device, for example, a liquid crystal display device or an organic EL display device in combination with a linear polarizing plate. In the present specification, the term "circularly polarized light" includes a circularly polarizing plate and an elliptical polarizing plate. Further, "circularly polarized light" includes circularly polarized light and elliptically polarized light.
　位相差膜７Ａは、位相差膜の波長５５０ｎｍにおける面内位相差値が３００ｎｍ以下であり、例えば、位相差膜７Ａはλ／４板である。本実施形態において、位相差膜７Ａは、重合性液晶化合物の硬化物からなる。重合性液晶化合物の硬化物からなる位相差膜７Ａは、通常厚さが０．２μｍ～１０μｍ程度と薄く、異物等を含む場合にその部分で位相差値が低下しやすい。 The retardation film 7A has an in-plane retardation value of 300 nm or less at a wavelength of 550 nm of the retardation film. For example, the retardation film 7A is a λ / 4 plate. In the present embodiment, the retardation film 7A is made of a cured product of a polymerizable liquid crystal compound. The retardation film 7A made of a cured product of a polymerizable liquid crystal compound usually has a thin thickness of about 0.2 μm to 10 μm, and when foreign matter or the like is contained, the retardation value tends to decrease at that portion.
　位相差膜７Ａを形成し得る重合性液晶化合物は、例えば、特開２００９－１７３８９３号公報、特開２０１０－３１２２３号公報、ＷＯ２０１２／１４７９０４号公報、ＷＯ２０１４／１０３２５号公報及びＷＯ２０１７－４３４３８号公報に開示されたものを挙げることができる。これらの公報に記載の重合性液晶化合物は、広い波長域において一様の偏光変換が可能な、いわゆる逆波長分散性を有する位相差膜を形成可能である。 The polymerizable liquid crystal compounds capable of forming the retardation film 7A are described in, for example, JP-A-2009-173893, JP-A-2010-31223, WO2012 / 147904, WO2014 / 10325 and WO2017-43438. The disclosed ones can be mentioned. The polymerizable liquid crystal compounds described in these publications can form a retardation film having so-called anti-wavelength dispersibility, which enables uniform polarization conversion in a wide wavelength range.
　位相差膜７Ａの形成方法としては、当該重合性液晶化合物を含む溶液（重合性液晶化合物溶液；液状組成物）を基材フィルム８Ａ上に塗布（塗工）して塗工膜をつくり、これを光重合させることで、上述のように極めて薄いものを形成することができる。かかる基材フィルム８Ａには、重合性液晶化合物を配向させるために配向膜が設けられていてもよい。配向膜は偏光照射により光配向させるものや、ラビング処理により機械的に配向させたもののいずれでもよい。なお、かかる配向膜の具体例としては、上記公報に記載されているものを用いることができる。このようにして形成した位相差膜７Ａは、別のフィルムに対して基材フィルム８Ａごと貼合し、その後、基材フィルム８Ａを剥がすことで、位相差膜７Ａをその別のフィルム上に転写することができる。 As a method for forming the retardation film 7A, a solution containing the polymerizable liquid crystal compound (polymerizable liquid crystal compound solution; liquid composition) is applied (coated) on the base film 8A to form a coating film. By photopolymerizing the above, an extremely thin film can be formed as described above. The base film 8A may be provided with an alignment film for orienting the polymerizable liquid crystal compound. The alignment film may be either photo-aligned by polarization irradiation or mechanically oriented by rubbing treatment. As a specific example of such an alignment film, those described in the above publication can be used. The retardation film 7A formed in this manner is bonded together with the base film 8A to another film, and then the base film 8A is peeled off to transfer the retardation film 7A onto the other film. can do.
　位相差膜７Ａの形成に際し、重合性液晶化合物溶液を塗布する基材フィルム８Ａに異物等が存在していたり、基材フィルム８Ａ自体に傷等があったりする場合に、重合性液晶化合物溶液を塗布して得られる塗布膜自体に欠陥が生じることがある。また、配向膜をラビング処理した場合には、ラビング布の屑が配向膜上に残り、これが重合性液晶化合物溶液（液晶硬化膜形成用組成物）の塗布膜に欠陥を生じさせることもある。このように、重合性液晶化合物から位相差膜を形成する場合、厚さが極めて薄い位相差膜を形成可能であるが、上記のような屑や傷等が当該位相差膜に光学欠陥を生じる要因となることがある When forming the retardation film 7A, if foreign matter or the like is present on the base film 8A to which the polymerizable liquid crystal compound solution is applied, or if the base film 8A itself is scratched or the like, the polymerizable liquid crystal compound solution is used. Defects may occur in the coating film itself obtained by coating. Further, when the alignment film is rubbed, debris of the rubbing cloth remains on the alignment film, which may cause a defect in the coating film of the polymerizable liquid crystal compound solution (composition for forming a liquid crystal cured film). As described above, when the retardation film is formed from the polymerizable liquid crystal compound, it is possible to form the retardation film having an extremely thin thickness, but the above-mentioned dusts and scratches cause optical defects in the retardation film. May be a factor
　重合性液晶化合物溶液を塗布する基材フィルム８Ａは、位相差膜７Ａの欠陥検査の際に位相差膜７Ａと積層状態にあるものであるので、位相差値が小さいことが望ましい。しかしながら、本実施形態においては、基材フィルム８Ａは、波長５５０ｎｍにおける面内位相差値が５０ｎｍ以上である。当該面内位相差値は、１００ｎｍ以上であってもよく、５００ｎｍ以上であってもよく、１０００ｎｍ以上であってもよく、２０００ｎｍ以上であってもよく、５０００ｎｍ以上であってもよく、８０００ｎｍ以上であってもよい。基材フィルム８Ａがこのような位相差を有する場合であっても、本実施形態の検査装置によれば、基材フィルム８Ａが有する位相差の影響を受けずに、位相差膜７Ａの欠陥の有無の判断を容易に行うことができる。 Since the base film 8A to which the polymerizable liquid crystal compound solution is applied is in a laminated state with the retardation film 7A at the time of defect inspection of the retardation film 7A, it is desirable that the retardation value is small. However, in the present embodiment, the base film 8A has an in-plane retardation value of 50 nm or more at a wavelength of 550 nm. The in-plane retardation value may be 100 nm or more, 500 nm or more, 1000 nm or more, 2000 nm or more, 5000 nm or more, 8000 nm or more. It may be. Even when the base film 8A has such a retardation, according to the inspection apparatus of the present embodiment, defects of the retardation film 7A are not affected by the retardation of the base film 8A. The presence or absence can be easily determined.
　基材フィルム８Ａを構成する材料としては上述の公報に記載されたものを挙げることができ、なかでもポリエチレンテレフタレート（ＰＥＴ）が好ましい。基材フィルム８Ａの厚さは、１０～５００μｍであってもよく、３０～３００μｍであってもよく、５０～２００μｍであってもよく、８０～１５０μｍであってもよい。 Examples of the material constituting the base film 8A include those described in the above-mentioned publication, and polyethylene terephthalate (PET) is particularly preferable. The thickness of the base film 8A may be 10 to 500 μm, 30 to 300 μm, 50 to 200 μm, or 80 to 150 μm.
　検査装置１Ａにおいて、第１の直線偏光板３は、光源２から入射した光を直線偏光に変換するフィルムであり、偏光フィルムの少なくとも一方の面に保護フィルムが貼合されてなるものである。偏光フィルムとしては、例えば、ポリビニルアルコールフィルムにヨウ素や二色性色素が吸着・配向されたものや、重合性液晶化合物を配向・重合したものに、二色性色素が吸着・配向したものが挙げられる。 In the inspection device 1A, the first linear polarizing plate 3 is a film that converts the light incident from the light source 2 into linearly polarized light, and is formed by laminating a protective film on at least one surface of the polarizing film. Examples of the polarizing film include a polyvinyl alcohol film in which iodine and a dichroic dye are adsorbed and oriented, and a film in which a polymerizable liquid crystal compound is oriented and polymerized and a dichroic dye is adsorbed and oriented. Be done.
　前記の直線偏光板は、直線偏光を出射する透過軸方向と、それとは直交する方向に吸収軸を持つ。本実施形態では、便宜的に直線偏光を出射する方向を透過軸方向、遮断する方向を吸収軸方向と定義するが、遮断する方向の偏光が反射される偏光フィルムについて排除しているものではない。 The linear polarizing plate has an absorption axis in a transmission axis direction for emitting linearly polarized light and in a direction orthogonal to the transmission axis direction. In the present embodiment, for convenience, the direction in which linearly polarized light is emitted is defined as the transmission axis direction, and the direction in which linearly polarized light is emitted is defined as the absorption axis direction, but the polarizing film in which the polarized light in the blocking direction is reflected is not excluded. ..
　ここで保護フィルムは、偏光フィルムを保護するためのものである。保護フィルムとしては、適度な機械的強度を有する偏光板を得る目的で、偏光板の技術分野で汎用されているものが用いられる。典型的には、トリアセチルセルロース（ＴＡＣ）フィルム等のセルロースエステル系フィルム；環状オレフィン系フィルム；ポリエチレンテレフタレート（ＰＥＴ）フィルム等のポリエステル系フィルム：ポリメチルメタクリレート（ＰＭＭＡ）フィルム等の（メタ）アクリル系フィルム等である。また、偏光板の技術分野で汎用されている添加剤が、保護フィルムに含まれていてもよい。直線偏光板に用いられる保護フィルムの位相差は小さいことが好ましく、例えば、Ｒｅ（５５０）では、１０ｎｍ以下が好ましく、５ｎｍ以下が特に好ましい。 Here, the protective film is for protecting the polarizing film. As the protective film, a film widely used in the technical field of polarizing plates is used for the purpose of obtaining a polarizing plate having appropriate mechanical strength. Typically, a cellulose ester film such as a triacetyl cellulose (TAC) film; a cyclic olefin film; a polyester film such as a polyethylene terephthalate (PET) film: a (meth) acrylic film such as a polymethyl methacrylate (PMMA) film. It is a film or the like. Further, an additive widely used in the technical field of the polarizing plate may be contained in the protective film. The phase difference of the protective film used for the linear polarizing plate is preferably small. For example, Re (550) is preferably 10 nm or less, and particularly preferably 5 nm or less.
　光源２は、種々の市販品を用いることができるが、例えばレーザ光等の直線光（直線光に近似するものも含む）であることが有利である。光源２が発する光は無偏光であり、第１の直線偏光板３を通過し所定方向の偏光となり、更に位相差膜７Ａを通過して円偏光となる。すなわち、無偏光の光が第１の直線偏光板３及び位相差膜７Ａを通過することで、円偏光となる。 Various commercially available products can be used as the light source 2, but it is advantageous that the light source 2 is, for example, linear light such as laser light (including one that approximates linear light). The light emitted by the light source 2 is unpolarized, passes through the first linear polarizing plate 3 to be polarized in a predetermined direction, and further passes through the retardation film 7A to be circularly polarized light. That is, unpolarized light passes through the first linear polarizing plate 3 and the retardation film 7A, resulting in circularly polarized light.
　位相差フィルタ４は、位相差膜７Ｂを備えるものである。位相差フィルタ４は、波長５５０ｎｍにおける面内位相差値と、検査対象である位相差膜７Ａの波長５５０ｎｍにおける面内位相差値との合計が２５０ｎｍ～３００ｎｍとなるものを用いる。この合計は、２６０ｎｍ～２９０ｎｍであることが好ましく、２７０ｎｍ～２８０ｎｍであることがより好ましく、λ／２であることが更に好ましい。ここで「λ」とは測定波長（ここでは５５０ｎｍ）である。光学欠陥を輝度（明度）情報ΔＬ＊より判定する場合には、位相差フィルタ４は、被検査物１０と同一の構成を有するフィルムを用いることが好ましい。また、光学欠陥を色差情報ΔＥ＊より判定する場合には、位相差フィルタ４は、被検査物１０と逆の波長分散性を有するフィルムを用いることが好ましい。また、位相差フィルタ４を配置する向きとしては、位相差膜７Ａの遅相軸と、位相差フィルタ４の遅相軸とが互いに平行となるようにする。すなわち、位相差フィルタ４は、被検査物１０を検査する場面では、常に被検査物１０中の位相差膜７Ａと併せて直線偏光の偏光軸を同じ向きに回転させるように、その向きが調整される。好ましくは、位相差膜７Ａと位相差フィルタ４との二つでλ／２板として振舞う。 The retardation filter 4 includes a retardation film 7B. As the retardation filter 4, the in-plane retardation value at a wavelength of 550 nm and the in-plane retardation value of the retardation film 7A to be inspected at a wavelength of 550 nm are 250 nm to 300 nm in total. The total is preferably 260 nm to 290 nm, more preferably 270 nm to 280 nm, and even more preferably λ / 2. Here, "λ" is a measurement wavelength (here, 550 nm). When the optical defect is determined from the luminance (brightness) information ΔL *, it is preferable to use a film having the same configuration as that of the object 10 to be inspected for the retardation filter 4. Further, when the optical defect is determined from the color difference information ΔE *, it is preferable to use a film having a wavelength dispersibility opposite to that of the object 10 to be inspected for the phase difference filter 4. Further, the retardation filter 4 is arranged so that the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are parallel to each other. That is, when inspecting the object 10 to be inspected, the retardation filter 4 is adjusted so that the polarization axis of linearly polarized light is always rotated in the same direction together with the retardation film 7A in the object 10 to be inspected. Will be done. Preferably, the retardation film 7A and the retardation filter 4 act as a λ / 2 plate.
　また位相差フィルタ４は、さらにポジティブＣプレートを備えていてもよい。ポジティブＣプレートは、位相差膜７Ａと向かい合う側の面に備えていてもよく、その反対側の面に備えていてもよい。ポジティブＣプレートを用いることで検査領域を拡大することができる。ポジティブＣプレートの厚み方向の位相差値（Ｒｔｈ（５５０））は、検査する位相差膜７Ａの厚み方向の位相差値によって適宜選択すればよいが、例えば、位相差膜７Ａがλ／４板である場合には、厚み方向の位相差値（Ｒｔｈ（５５０））を－５０ｎｍ～－３００ｎｍのものを用いることで効果を得られやすい。 Further, the phase difference filter 4 may further include a positive C plate. The positive C plate may be provided on the surface facing the retardation film 7A, or may be provided on the surface opposite to the retardation film 7A. The inspection area can be expanded by using the positive C plate. The retardation value (Rth (550)) in the thickness direction of the positive C plate may be appropriately selected according to the retardation value in the thickness direction of the retardation film 7A to be inspected. For example, the retardation film 7A is a λ / 4 plate. In the case of, the effect can be easily obtained by using a phase difference value (Rth (550)) in the thickness direction of −50 nm to −300 nm.
　位相差フィルタ４は、位相差膜７Ｂと、位相差膜７Ｂが積層された基材フィルム８Ｂとを備えるものでもよい。基材フィルム８Ｂは、位相差膜７Ｂの光学特性を損なわないように面内位相差値（Ｒｅ（５５０））が、実質的にゼロのものを用いる。ここで面内位相差が実質的にゼロとは、面内位相差値（Ｒｅ（５５０））が３ｎｍ以下であることをいう。 The retardation filter 4 may include a retardation film 7B and a base film 8B on which the retardation film 7B is laminated. As the base film 8B, a film having an in-plane retardation value (Re (550)) of substantially zero is used so as not to impair the optical characteristics of the retardation film 7B. Here, when the in-plane phase difference is substantially zero, it means that the in-plane phase difference value (Re (550)) is 3 nm or less.
　ここで、波長５５０ｎｍにおける面内位相差値（Ｒｅ（５５０））及び厚み方向の位相差値（Ｒｔｈ（５５０））の求め方を示しておく。上記のとおり、測定対象のフィルムから例えば、４０ｍｍ×４０ｍｍ程度の大きさの片を分取（長尺フィルムから、適当な切断具を用いて分取する等）する。この片のＲｅ（５５０）を３回測定し、Ｒｅ（５５０）の平均値を求める。片のＲｅ（５５０）は、位相差測定装置ＫＯＢＲＡ－ＷＰＲ（王子計測機器株式会社製）を用い、測定温度室温（２３℃）で測定することができる。 Here, how to obtain the in-plane retardation value (Re (550)) and the thickness direction retardation value (Rth (550)) at a wavelength of 550 nm will be shown. As described above, for example, a piece having a size of about 40 mm × 40 mm is separated from the film to be measured (from a long film, separated by using an appropriate cutting tool, etc.). Re (550) of this piece is measured three times, and the average value of Re (550) is obtained. One piece of Re (550) can be measured at a measurement temperature of room temperature (23 ° C.) using a phase difference measuring device KOBRA-WPR (manufactured by Oji Measuring Instruments Co., Ltd.).
　第２の直線偏光板５は、位相差フィルタ４を通過した光が入射するフィルムであり、その構成や材料については、第１の直線偏光板３と同様である。検査装置１Ａにおいて、第２の直線偏光板５は、図２（Ａ）及び図２（Ｂ）に示されているとおり、光源２からカメラ６へ向かう光の光軸９の方向から見た場合に第１の直線偏光板３の透過軸ｐと位相差膜７Ａの遅相軸ｑとがなす角度θ１と、第２の直線偏光板５の吸収軸ｒと位相差膜７Ａの遅相軸ｑとがなす角度θ２とが互いに略同一となるように配置される。換言すれば、位相差膜７Ａの遅相軸ｑを対称軸として、第１の直線偏光板３の透過軸ｐと第２の直線偏光板５の吸収軸ｒが略線対称となるように配置される。ここで、角度θ１及びθ２は、いずれも鋭角（θ１＜９０°、θ２＜９０°）側の角度又は直角を指すものとする。図２（Ｂ）では、 The second linear polarizing plate 5 is a film into which light that has passed through the retardation filter 4 is incident, and its configuration and material are the same as those of the first linear polarizing plate 3. In the inspection device 1A, when the second linear polarizing plate 5 is viewed from the direction of the optical axis 9 of the light from the light source 2 toward the camera 6 as shown in FIGS. 2 (A) and 2 (B). The angle θ 1 formed by the transmission axis p of the first linear polarizing plate 3 and the slow axis q of the retardation film 7A, the absorption axis r of the second linear polarizing plate 5, and the slow axis of the retardation film 7A. They are arranged so that the angle θ 2 formed by q is substantially the same as each other. In other words, with the slow axis q of the retardation film 7A as the axis of symmetry, the transmission axis p of the first linear polarizing plate 3 and the absorption axis r of the second linear polarizing plate 5 are arranged so as to be substantially line symmetric. Will be done. Here, the angles θ 1 and θ 2 both refer to angles or right angles on the acute angle (θ 1 <90 °, θ 2 <90 °) side. In FIG. 2 (B),
　さらに、検査領域を拡大するために、第１の直線偏光板３と基材フィルム８Ａの間に、ポジティブＣプレートを配置してもよい。ポジティブＣプレートの厚み方向の位相差値（Ｒｔｈ（５５０））は、基材フィルム８Ａの厚み方向の位相差値によって適宜選択すればよいが、例えば、基材フィルム８Ａの厚み方向の位相差値（Ｒｔｈ（５５０））の１／３～２／３程度の厚み方向の位相差値とすることで効果を得られやすい。 Further, in order to expand the inspection area, a positive C plate may be arranged between the first linear polarizing plate 3 and the base film 8A. The retardation value (Rth (550)) in the thickness direction of the positive C plate may be appropriately selected according to the retardation value in the thickness direction of the base film 8A. For example, the retardation value in the thickness direction of the base film 8A. The effect can be easily obtained by setting the phase difference value in the thickness direction to about 1/3 to 2/3 of (Rth (550)).
　本実施形態の検査装置１Ａでは、第１の直線偏光板３、被検査物１０、位相差フィルタ４、及び、第２の直線偏光板５を通過した光を観察するために、光軸９上、且つ、位相差フィルタ４の両側のうち光源２がある側とは反対側の位置に、カメラ（検出手段）６が配置されている。カメラ６は、例えばＣＣＤカメラであり、この場合ＣＣＤカメラと画像処理装置を組み合わせた画像処理解析により自動的に検出し、これによって被検査物１０の検査を行うことができる。或いは、検出手段としては、カメラ６に代えて人間が第２の直線偏光板５を目視観察することであってもよい。 In the inspection device 1A of the present embodiment, in order to observe the light that has passed through the first linear polarizing plate 3, the object to be inspected 10, the retardation filter 4, and the second linear polarizing plate 5, the light is on the optical axis 9. Moreover, the camera (detecting means) 6 is arranged at a position on both sides of the retardation filter 4 opposite to the side where the light source 2 is located. The camera 6 is, for example, a CCD camera. In this case, the camera 6 is automatically detected by image processing analysis in which the CCD camera and the image processing device are combined, whereby the object 10 to be inspected can be inspected. Alternatively, as the detection means, a human may visually observe the second linear polarizing plate 5 instead of the camera 6.
（検査方法）
　検査装置１Ａを用いた検査方法は、以下のとおりである。はじめに、検査装置１Ａの内部のうち、第１の直線偏光板３と位相差フィルタ４との間に被検査物１０を配置する。このとき、被検査物１０は、その基材フィルム８Ａの側が第１の直線偏光板３側を向くようにし、且つ、基材フィルム８Ａの遅相軸と第１の直線偏光板３の偏光軸（透過軸）とが互いに略直交するように又は略平行となるように配置する。そして、位相差膜７Ａの遅相軸と位相差フィルタ４の遅相軸とが互いに平行となるようにし、更に、図２に示されているとおり、光源２からカメラ６へ向かう光の光軸９の方向から見た場合に第１の直線偏光板３の透過軸ｐと位相差膜７Ａの遅相軸ｑとがなす角度θ１と、第２の直線偏光板５の吸収軸ｒと位相差膜７Ａの遅相軸ｑとがなす角度θ２とが互いに略同一となるように配置する。換言すれば、位相差膜７Ａの遅相軸ｑを対称軸として、第１の直線偏光板３の透過軸ｐと第２の直線偏光板５の吸収軸ｒが略線対称となるように配置する。なお、位相差膜７Ａの遅相軸と位相差フィルタ４の遅相軸とが互いに平行とするので、光源２からカメラ６へ向かう光の光軸９の方向から見た場合に第１の直線偏光板３の透過軸ｐと位相差フィルタ４の遅相軸とがなす角度と、第２の直線偏光板５の吸収軸ｒと位相差フィルタ４の遅相軸とがなす角度とが互いに略同一となっている。 (Inspection method)
The inspection method using the inspection device 1A is as follows. First, in the inside of the inspection device 1A, the object 10 to be inspected is arranged between the first linear polarizing plate 3 and the retardation filter 4. At this time, the object 10 to be inspected has the base film 8A side facing the first linear polarizing plate 3 side, and the slow axis of the base film 8A and the polarizing axis of the first linear polarizing plate 3. Arrange so that the (transmission axis) is substantially orthogonal to or substantially parallel to each other. Then, the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are made parallel to each other, and further, as shown in FIG. 2, the optical axis of light from the light source 2 toward the camera 6 When viewed from the direction of 9, the angle θ 1 formed by the transmission axis p of the first linear polarizing plate 3 and the slow axis q of the retardation film 7A, and the absorption axis r and position of the second linear polarizing plate 5. The retarding film 7A is arranged so that the angle θ 2 formed by the slow axis q and the retarding axis q are substantially the same as each other. In other words, with the slow axis q of the retardation film 7A as the axis of symmetry, the transmission axis p of the first linear polarizing plate 3 and the absorption axis r of the second linear polarizing plate 5 are arranged so as to be substantially line symmetric. To do. Since the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are parallel to each other, the first straight line when viewed from the direction of the optical axis 9 of the light from the light source 2 to the camera 6. The angle formed by the transmission axis p of the polarizing plate 3 and the slow axis of the retardation filter 4 and the angle formed by the absorption axis r of the second linear polarizing plate 5 and the slow axis of the retardation filter 4 are approximately mutually exclusive. It is the same.
　光源２から第１の直線偏光板３に向けて光を照射する。光源２が発した光は第１の直線偏光板３に入射し、ここで無偏光の光が直線偏光に変換される。そして、その直線偏光が被検査物１０に対して基材フィルム８Ａ側から入射する。基材フィルム８Ａを通過した直線偏光は、位相差膜７Ａを通過して円偏光となる。この円偏光が位相差フィルタ４に対して位相差膜７Ｂの側から入射する。ここで、位相差膜７Ａの遅相軸と、位相差フィルタ４の遅相軸とは互いに略平行となっており、且つ、位相差膜７Ａの波長５５０ｎｍにおける面内位相差値と、位相差フィルタ４の波長５５０ｎｍにおける面内位相差値との合計が２５０ｎｍ～３００ｎｍであるため、位相差フィルタ４を通過した光は直線偏光となっており、その直線偏光は、被検査物に入射する直前の直線偏光と比べて約λ/２の位相差が生じていることになる。そして、第２の直線偏光板５は、光軸９の方向から見た場合に第１の直線偏光板３の透過軸と位相差膜７Ａの遅相軸とがなす角度θ１と、第２の直線偏光板５の吸収軸と位相差膜７Ａの遅相軸とがなす角度θ２とが互いに略同一となるように配置されているので、位相差フィルタ４を通過して直線偏光に戻った光は第２の直線偏光板５によって遮断される。この検査において、被検査物１０中の位相差膜７Ａに欠陥が存在しない場合は、カメラ６による観察では第２の直線偏光板５は全面が均一な黒色に見える。
これに対し、被検査物１０中の位相差膜７Ａに欠陥が存在する場合、この欠陥部分を通過した光は想定される直線偏光にならず、楕円偏光となる。したがって、第２の直線偏光板５では正規の遮断が行えず光が漏れ、カメラ６による観察では当該欠陥部分が輝点として観察される。 Light is emitted from the light source 2 toward the first linear polarizing plate 3. The light emitted by the light source 2 is incident on the first linear polarizing plate 3, where the unpolarized light is converted into linearly polarized light. Then, the linearly polarized light is incident on the object 10 to be inspected from the base film 8A side. The linearly polarized light that has passed through the base film 8A passes through the retardation film 7A and becomes circularly polarized light. This circularly polarized light is incident on the retardation filter 4 from the retardation film 7B side. Here, the slow axis of the retardation film 7A and the slow axis of the retardation filter 4 are substantially parallel to each other, and the in-plane retardation value of the retardation film 7A at a wavelength of 550 nm and the phase difference. Since the total of the in-plane retardation value at the wavelength of 550 nm of the filter 4 is 250 nm to 300 nm, the light passing through the retardation filter 4 is linearly polarized light, and the linearly polarized light is immediately before incident on the object to be inspected. This means that a phase difference of about λ / 2 is generated as compared with the linearly polarized light of. The second linear polarizing plate 5 has an angle θ 1 formed by the transmission axis of the first linear polarizing plate 3 and the slow axis of the retardation film 7A when viewed from the direction of the optical axis 9, and a second. Since the angle θ 2 formed by the absorption axis of the linear polarizing plate 5 and the slow axis of the retardation film 7A is arranged to be substantially the same as each other, it passes through the retardation filter 4 and returns to linearly polarized light. The light is blocked by the second linear polarizing plate 5. In this inspection, when there is no defect in the retardation film 7A in the object to be inspected 10, the entire surface of the second linear polarizing plate 5 looks uniform black when observed by the camera 6.
On the other hand, when the retardation film 7A in the object 10 to be inspected has a defect, the light passing through the defect portion does not become the expected linearly polarized light but becomes elliptically polarized light. Therefore, the second linear polarizing plate 5 cannot perform regular blocking and light leaks, and the defective portion is observed as a bright spot in the observation by the camera 6.
　ここで、基材フィルム８Ａは「波長５５０ｎｍにおける面内位相差値が５０ｎｍ以上」という位相差を有しているので、第１の直線偏光板３を通過した光の偏光状態が基材フィルム８Ａによって乱され得る。しかしながら、本実施形態の検査方法では、位相差を有する基材フィルム８Ａの遅相軸に対して第１の直線偏光板３の透過軸を互いに略直交するように又は略平行となるように配置しているので、第１の直線偏光板３を通過した光の偏光状態が基材フィルム８Ａによって乱されることがない。すなわち、組んだ光学系が意図したとおりに機能し、位相差膜７Ａに欠陥があった場合に観察視野においてその欠陥を適切に認識することができる。従来は、基材フィルム８Ａの面内位相差値が５０ｎｍ以上である場合は、第１の直線偏光板３を通過した光が基材フィルム８Ａが有する位相差によって円偏光（楕円偏光）とされ、その結果第２の直線偏光板５から漏れる光が多くなり、検査の障害となっていた。したがって、本実施形態の検査方法によれば、基材フィルム８Ａが有する面内位相差の影響を抑制しながら位相差膜の欠陥の有無を容易に判断することができる。 Here, since the base film 8A has a phase difference of "the in-plane retardation value at a wavelength of 550 nm is 50 nm or more", the polarized state of the light passing through the first linear polarizing plate 3 is the base film 8A. Can be disturbed by. However, in the inspection method of the present embodiment, the transmission axes of the first linear polarizing plate 3 are arranged so as to be substantially orthogonal to or substantially parallel to the slow axis of the base film 8A having a phase difference. Therefore, the polarization state of the light that has passed through the first linear polarizing plate 3 is not disturbed by the base film 8A. That is, the assembled optical system functions as intended, and when the retardation film 7A has a defect, the defect can be appropriately recognized in the observation field of view. Conventionally, when the in-plane retardation value of the base film 8A is 50 nm or more, the light passing through the first linear polarizing plate 3 is circularly polarized (elliptical polarized light) due to the retardation of the base film 8A. As a result, the amount of light leaking from the second linear polarizing plate 5 increased, which hindered the inspection. Therefore, according to the inspection method of the present embodiment, it is possible to easily determine the presence or absence of defects in the retardation film while suppressing the influence of the in-plane retardation of the base film 8A.
（連続検査方法）
　本実施形態の検査方法は、図３に示されているとおり、位相差膜７Ａを基材フィルム８Ａ上に連続形成する工程と併せて、これと同一の製造ラインにて連続的に行うことができる。図３に示されている検査システム１００は、上述した検査装置１Ａに加え、位相差膜７Ａが形成される前の基材フィルム８Ａの遅相軸（配向角）の方向を求める配向角測定器１２と、配向角測定器１２で求められた基材フィルム８Ａの遅相軸と第１の直線偏光板３の透過軸とが互いに略直交するように又は略平行となるように第１の直線偏光板３の角度を調節する角度調整機構１４とを備えており、インラインにて被検査物１０の検査を行う。ここで、被検査物１０は搬送されながら検査装置１Ａの光軸９内を通過し、欠陥の有無の検査を受ける。そして、検査を終えた被検査物１０は巻き取られる。なお、ここで基材フィルム８Ａの幅は、例えば０．５～２．０ｍであってもよく、１．０～１．５ｍであってもよい。 (Continuous inspection method)
As shown in FIG. 3, the inspection method of the present embodiment can be continuously performed on the same production line as the step of continuously forming the retardation film 7A on the base film 8A. it can. The inspection system 100 shown in FIG. 3 is an orientation angle measuring device that determines the direction of the slow axis (orientation angle) of the base film 8A before the retardation film 7A is formed, in addition to the inspection device 1A described above. The first straight line so that the slow axis of the base film 8A obtained by the orientation angle measuring device 12 and the transmission axis of the first linear polarizing plate 3 are substantially orthogonal to each other or substantially parallel to each other. It is provided with an angle adjusting mechanism 14 for adjusting the angle of the polarizing plate 3, and inspects the object 10 to be inspected in-line. Here, the object 10 to be inspected passes through the optical axis 9 of the inspection device 1A while being conveyed, and is inspected for defects. Then, the inspected object 10 that has been inspected is wound up. Here, the width of the base film 8A may be, for example, 0.5 to 2.0 m or 1.0 to 1.5 m.
　図４に示されているとおり、検査システム１００は、被検査物１０の幅方向（搬送方向に垂直な方向）に亘って複数の検査装置１Ａが配置されている。検査装置１Ａは、被検査物１０の幅方向に亘って５～２０箇所配置することが好ましい。図４では五個の検査装置１Ａが配置されている。 As shown in FIG. 4, in the inspection system 100, a plurality of inspection devices 1A are arranged in the width direction (direction perpendicular to the transport direction) of the object 10 to be inspected. The inspection device 1A is preferably arranged at 5 to 20 locations along the width direction of the object to be inspected 10. In FIG. 4, five inspection devices 1A are arranged.
　図３に示されている製造ラインでは、長尺の基材フィルム８Ａを搬送しながら、配向角測定器１２で基材フィルム８Ａの遅相軸の方向を測定する。このとき、基材フィルム８Ａが延伸により製造されたものである場合、図５に示されているとおり、その幅方向において遅相軸の方向が変化している。図５において、矢印はその部分における遅相軸の方向を表している。したがって、配向角測定器１２による測定は、基材フィルム８Ａの幅方向に亘る複数の箇所で行う。配向角測定器１２は、測定した遅相軸の情報を角度調整機構１４へ提供する。その後、基材フィルム８Ａを搬送しながら基材フィルム８Ａ上に重合性液晶化合物溶液を塗工機１６で塗布して塗工膜７ａをつくり、塗工機１６の下流側に配置された乾燥器１８で塗工膜７ａを乾燥させる。ここで、塗工された重合性液晶化合物は基材フィルム８Ａ上で配向し、乾燥・重合により硬化し、位相差膜７Ａとなる。乾燥したフィルムが被検査物１０であり、搬送の下流側に配置されている検査装置１Ａでの検査に供される。 In the production line shown in FIG. 3, the direction of the slow axis of the base film 8A is measured by the orientation angle measuring device 12 while transporting the long base film 8A. At this time, when the base film 8A is manufactured by stretching, the direction of the slow phase axis changes in the width direction as shown in FIG. In FIG. 5, the arrow indicates the direction of the slow axis at that portion. Therefore, the measurement by the orientation angle measuring device 12 is performed at a plurality of locations extending in the width direction of the base film 8A. The orientation angle measuring device 12 provides the measured information on the slow-phase axis to the angle adjusting mechanism 14. Then, while transporting the base film 8A, a polymerizable liquid crystal compound solution is applied onto the base film 8A with the coating machine 16 to form a coating film 7a, and a dryer arranged on the downstream side of the coating machine 16 The coating film 7a is dried at 18. Here, the coated polymerizable liquid crystal compound is oriented on the base film 8A and cured by drying and polymerization to form a retardation film 7A. The dried film is the object 10 to be inspected, and is subjected to inspection by the inspection device 1A arranged on the downstream side of the transport.
　角度調整機構１４は、配向角測定器１２から提供された基材フィルム８Ａの遅相軸方向の情報に基づいて、第１の直線偏光板３を回転させ、第１の直線偏光板３の透過軸が基材フィルム８Ａの遅相軸と略直交又は略平行となるようにする。併せて、位相差フィルタ４及び第２の直線偏光板５についても上記所定の関係となるように回転させる。被検査物１０の幅方向に配置された複数の検査装置１Ａは、それぞれ検査領域Ａ（図４参照）が割り当てられており、被検査物１０は、幅方向全ての領域に亘って検査される。検査においては、基材フィルム８Ａの遅相軸が幅方向に亘って変化していることに応じて、角度調整機構１４が、検査領域Ａごとに第１の直線偏光板３の透過軸が向く方向を異ならせることになる。なお、図５に示している検査領域Ａは、基材フィルム８Ａ上における、図４に示している検査領域Ａに対応する部分を示している。 The angle adjusting mechanism 14 rotates the first linear polarizing plate 3 based on the information in the slow axis direction of the base film 8A provided by the orientation angle measuring instrument 12, and transmits the first linear polarizing plate 3. The axis is made to be substantially orthogonal or substantially parallel to the slow axis of the base film 8A. At the same time, the retardation filter 4 and the second linear polarizing plate 5 are also rotated so as to have the above-mentioned predetermined relationship. An inspection area A (see FIG. 4) is assigned to each of the plurality of inspection devices 1A arranged in the width direction of the object 10 to be inspected, and the object 10 to be inspected is inspected over the entire area in the width direction. .. In the inspection, the angle adjusting mechanism 14 faces the transmission axis of the first linear polarizing plate 3 for each inspection region A according to the slow axis of the base film 8A changing in the width direction. It will be in a different direction. The inspection area A shown in FIG. 5 indicates a portion on the base film 8A corresponding to the inspection area A shown in FIG.
　検査システム１００を用いることにより、基材フィルム８Ａの搬送方向に亘って位相差膜７Ａの形成と検査を連続的に効率よく実施することができるので、被検査物１０の製造と検査が効率化される。また、検査システム１００では被検査物１０の幅方向に複数の検査装置１Ａを配置しているので、基材フィルム８Ａの遅相軸の方向が幅方向において異なっている場合でも、個々の検査装置１Ａにおける第１の直線偏光板３の透過軸と基材フィルム８Ａのその検査領域Ａにおける遅相軸との関係を所定の関係に調整することができる。すなわち、基材フィルム８Ａの幅方向のあらゆる箇所において、基材フィルム８Ａが有する面内位相差の影響を抑制した検査を行うことができる。 By using the inspection system 100, the retardation film 7A can be continuously and efficiently formed and inspected in the transport direction of the base film 8A, so that the production and inspection of the inspected object 10 can be made more efficient. Will be done. Further, in the inspection system 100, since a plurality of inspection devices 1A are arranged in the width direction of the object 10 to be inspected, even if the directions of the slow axes of the base film 8A are different in the width direction, the individual inspection devices are arranged. The relationship between the transmission axis of the first linear polarizing plate 3 in 1A and the slow axis in the inspection region A of the base film 8A can be adjusted to a predetermined relationship. That is, it is possible to perform an inspection in which the influence of the in-plane retardation of the base film 8A is suppressed at any position in the width direction of the base film 8A.
＜第２の実施形態＞
　本発明の第２の実施形態について説明する。第２の実施形態として図６に示されている検査装置１Ｂが第１の実施形態の検査装置１Ａと異なる点は、光源２と検出手段との位置が逆になっている点である。すなわち、検査装置１Ｂは、カメラ（検出手段）６、第１の直線偏光板３、位相差フィルタ４、第２の直線偏光板５、及び、光源２がこの順に配置されてなるものである。図６では、第１の直線偏光板３と位相差フィルタ４との間に、検査対象である被検査物１０を配置した様子を描いている。ここでは、被検査物１０と第２の直線偏光板５との配置に関し、基材フィルム８Ａの遅相軸と第２の直線偏光板５の透過軸とが互いに略直交するように又は略平行となるように配置する。 <Second embodiment>
A second embodiment of the present invention will be described. The inspection device 1B shown in FIG. 6 as the second embodiment is different from the inspection device 1A of the first embodiment in that the positions of the light source 2 and the detection means are reversed. That is, the inspection device 1B includes a camera (detection means) 6, a first linear polarizing plate 3, a retardation filter 4, a second linear polarizing plate 5, and a light source 2 arranged in this order. FIG. 6 depicts a state in which the object to be inspected 10 to be inspected is arranged between the first linear polarizing plate 3 and the retardation filter 4. Here, regarding the arrangement of the object 10 to be inspected and the second linear polarizing plate 5, the slow axis of the base film 8A and the transmission axis of the second linear polarizing plate 5 are substantially orthogonal to each other or substantially parallel to each other. Arrange so that
　この検査装置１Ｂを用いた被検査物１０の検査においても、第１の実施形態と同様の原理によって位相差膜７Ａの欠陥の有無を容易に検査することができる。 In the inspection of the object to be inspected 10 using this inspection device 1B, the presence or absence of defects in the retardation film 7A can be easily inspected by the same principle as in the first embodiment.
　以上、本発明の好適な実施形態について説明したが、本発明は上記実施形態に何ら限定されるものではない。 Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.
　本発明は、位相差膜の欠陥の有無を判断する検査に利用することができる。 The present invention can be used for an inspection for determining the presence or absence of defects in the retardation film.
　１Ａ，１Ｂ…検査装置、２…光源、３…第１の直線偏光板、４…位相差フィルタ、５…第２の直線偏光板、６…カメラ（検出手段）、７Ａ，７Ｂ…位相差膜、７ａ…塗工膜、８Ａ，８Ｂ…基材フィルム、９…光軸、１０…被検査物、１２…配向角測定器、１４…角度調整機構、１６…塗工機、１８…乾燥器、１００…検査システム、Ａ…検査領域、ｐ…第１の直線偏光板の透過軸、ｑ…位相差膜７Ａの遅相軸、ｒ…第２の直線偏光板の吸収軸。

  1A, 1B ... Inspection device, 2 ... Light source, 3 ... First linear polarizing plate, 4 ... Phase difference filter, 5 ... Second linear polarizing plate, 6 ... Camera (detection means), 7A, 7B ... Phase difference film , 7a ... Coating film, 8A, 8B ... Base film, 9 ... Optical axis, 10 ... Inspected object, 12 ... Orientation angle measuring instrument, 14 ... Angle adjustment mechanism, 16 ... Coating machine, 18 ... Dryer, 100 ... Inspection system, A ... Inspection region, p ... Transmission axis of the first linear polarizing plate, q ... Slow axis of the retardation film 7A, r ... Absorption axis of the second linear polarizing plate.

Claims (7)

  1. 　波長５５０ｎｍにおける面内位相差値が５０ｎｍ以上である基材フィルムと、前記基材フィルムの片面に形成された重合性液晶化合物の硬化物からなる位相差膜とを備えるフィルム状の被検査物に光を入射して前記位相差膜の欠陥の有無を判断する検査方法であって、
    　第１の直線偏光板と、
    　前記被検査物と、
    　位相差フィルタと、
    　第２の直線偏光板と、をこの順に並ぶように配置し、
    　前記被検査物は、前記基材フィルム側の面が前記第１の直線偏光板側を向いており、
    　前記基材フィルムの遅相軸と、前記第１の直線偏光板又は前記第２の直線偏光板の透過軸とは互いに略直交しており又は略平行であり、
    　前記位相差膜の遅相軸と、前記位相差フィルタの遅相軸とは互いに略平行であり、
    　前記位相差膜の波長５５０ｎｍにおける面内位相差値は、３００ｎｍ以下であり、
    　前記位相差膜の波長５５０ｎｍにおける面内位相差値と、前記位相差フィルタの波長５５０ｎｍにおける面内位相差値との合計が、２５０ｎｍ～３００ｎｍであり、
    　前記光の光軸方向から見た場合に、前記位相差膜の遅相軸を対称軸として、前記第１の直線偏光板の透過軸と前記第２の直線偏光板の吸収軸が略線対称となるように配置し、
    　前記第１の直線偏光板側又は前記第２の直線偏光板側のいずれか一方側から、光軸が前記被検査物上の所定の検査領域を通過するように光を入射し、その他方側から前記第２の直線偏光板又は前記第１の直線偏光板を観察する、検査方法。     A film-like object to be inspected including a base film having an in-plane retardation value of 50 nm or more at a wavelength of 550 nm and a retardation film made of a cured product of a polymerizable liquid crystal compound formed on one side of the base film. This is an inspection method in which light is incident to determine the presence or absence of defects in the retardation film.
    The first linear polarizing plate and
    With the object to be inspected
    With a phase difference filter,
    The second linear polarizing plate and the second linear polarizing plate are arranged so as to be arranged in this order.
    In the object to be inspected, the surface on the base film side faces the first linear polarizing plate side.
    The slow axis of the base film and the transmission axis of the first linear polarizing plate or the second linear polarizing plate are substantially orthogonal or substantially parallel to each other.
    The slow axis of the retardation film and the slow axis of the retardation filter are substantially parallel to each other.
    The in-plane retardation value of the retardation film at a wavelength of 550 nm is 300 nm or less.
    The total of the in-plane retardation value of the retardation film at a wavelength of 550 nm and the in-plane retardation value of the retardation filter at a wavelength of 550 nm is 250 nm to 300 nm.
    When viewed from the optical axis direction of the light, the transmission axis of the first linear polarizing plate and the absorption axis of the second linear polarizing plate are substantially axisymmetric with the slow axis of the retardation film as the axis of symmetry. Arrange so that
    Light is incident from either the first linear polarizing plate side or the second linear polarizing plate side so that the optical axis passes through a predetermined inspection region on the object to be inspected, and the other side. An inspection method for observing the second linear polarizing plate or the first linear polarizing plate.
  2. 　前記位相差膜が形成される前の前記基材フィルムを対象として、配向角測定器を用いて前記基材フィルムの遅相軸の方向を予め求める工程を有する、請求項１記載の検査方法。 The inspection method according to claim 1, further comprising a step of previously determining the direction of the slow axis of the base film using an orientation angle measuring device for the base film before the retardation film is formed.
  3. 　前記配向角測定器により前記基材フィルムの遅相軸を求めた後に、前記基材フィルムの片面に、重合性液晶化合物を含む液状組成物を塗工して前記基材フィルムの表面上に前記重合性液晶化合物を含む塗工膜を形成し、前記塗工膜に含まれる前記重合性液晶化合物を配向及び硬化させて前記位相差膜を形成する工程を有する、請求項２記載の検査方法。 After determining the slow phase axis of the base film with the orientation angle measuring device, a liquid composition containing a polymerizable liquid crystal compound is applied to one side of the base film, and the surface of the base film is coated with the liquid composition. The inspection method according to claim 2, further comprising a step of forming a coating film containing a polymerizable liquid crystal compound, orienting and curing the polymerizable liquid crystal compound contained in the coating film to form the retardation film.
  4. 　前記被検査物を、前記第１の直線偏光板と前記位相差フィルタとの間で前記被検査物の長さ方向に搬送させながら、前記長さ方向に連続して検査を行う、請求項１～３のいずれか一項記載の検査方法。 Claim 1 in which the object to be inspected is continuously inspected in the length direction while being conveyed between the first linear polarizing plate and the retardation filter in the length direction of the object to be inspected. The inspection method according to any one of 3 to 3.
  5. 　前記検査領域を、前記被検査物の幅方向に複数箇所設ける、請求項１～４のいずれか一項記載の検査方法。 The inspection method according to any one of claims 1 to 4, wherein the inspection areas are provided at a plurality of locations in the width direction of the object to be inspected.
  6. 　波長５５０ｎｍにおける面内位相差値が５０ｎｍ以上である基材フィルムと、前記基材フィルムの片面に形成された重合性液晶化合物の硬化物からなる位相差膜とを備えるフィルム状の被検査物に光を入射して前記位相差膜の欠陥の有無を判断する検査装置であって、
    　前記被検査物が配置される場所を挟むようにして配置された第１の直線偏光板及び位相差フィルタと、前記位相差フィルタに関して前記被検査物が配置される場所とは反対側の領域に配置された第２の直線偏光板と、前記第１の直線偏光板又は前記第２の直線偏光板に関して前記被検査物が配置される場所とは反対側の領域に配置された光源と、を備え、　前記第１の直線偏光板又は前記第２の直線偏光板は、その透過軸が前記基材フィルムの遅相軸と互いに略直交するように又は略平行となるように配置されており、
    　前記位相差フィルタは、その遅相軸が前記位相差膜の遅相軸と互いに略平行となるように配置されており、
    　前記位相差フィルタの波長５５０ｎｍにおける面内位相差値は、前記位相差膜の波長５５０ｎｍにおける面内位相差値との合計が２５０ｎｍ～３００ｎｍとなる値であり、
    　前記光の光軸方向から見た場合に、前記位相差膜の遅相軸を対称軸として、前記第１の直線偏光板の透過軸と前記第２の直線偏光板の吸収軸が略線対称となるように配置されており、
    　前記光源は、その光軸上に前記第１の直線偏光板、前記被検査物上の所定の検査領域、前記位相差フィルタ、及び、前記第２の直線偏光板が並ぶ位置に配置されている、検査装置。     A film-like object to be inspected including a base film having an in-plane retardation value of 50 nm or more at a wavelength of 550 nm and a retardation film made of a cured product of a polymerizable liquid crystal compound formed on one side of the base film. An inspection device that injects light to determine the presence or absence of defects in the retardation film.
    The first linear polarizing plate and the retardation filter arranged so as to sandwich the place where the object to be inspected is arranged, and the retardation filter are arranged in the region opposite to the place where the object to be inspected is arranged. A second linear polarizing plate and a light source arranged in a region of the first linear polarizing plate or the second linear polarizing plate opposite to the place where the object to be inspected is arranged are provided. The first linear polarizing plate or the second linear polarizing plate is arranged so that its transmission axis is substantially orthogonal to or substantially parallel to the slow axis of the base film.
    The retardation filter is arranged so that its slow axis is substantially parallel to the slow axis of the retardation film.
    The in-plane retardation value of the retardation filter at a wavelength of 550 nm is a value at which the total of the in-plane retardation value of the retardation film at a wavelength of 550 nm is 250 nm to 300 nm.
    When viewed from the optical axis direction of the light, the transmission axis of the first linear polarizing plate and the absorption axis of the second linear polarizing plate are substantially axisymmetric with the slow axis of the retardation film as the axis of symmetry. It is arranged so that
    The light source is arranged at a position where the first linear polarizing plate, a predetermined inspection region on the object to be inspected, the retardation filter, and the second linear polarizing plate are arranged on the optical axis. , Inspection equipment.
  7. 　請求項６記載の検査装置と、
    　前記位相差膜が形成される前の前記基材フィルムの遅相軸を求める配向角測定器と、
    　前記配向角測定器で求められた前記基材フィルムの遅相軸と前記第１の直線偏光板の透過軸とが互いに略直交するように又は略平行となるように前記第１の直線偏光板の角度を調節する角度調整機構と、を備える、検査システム。

          The inspection device according to claim 6 and
    An orientation angle measuring instrument for determining the slow axis of the base film before the retardation film is formed, and
    The first linear polarizing plate so that the slow axis of the base film and the transmission axis of the first linear polarizing plate obtained by the orientation angle measuring device are substantially orthogonal to each other or substantially parallel to each other. An inspection system equipped with an angle adjustment mechanism that adjusts the angle of.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023189090A1 (en) * 2022-03-31 2023-10-05 住友化学株式会社 Test method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006003174A (en) * 2004-06-16 2006-01-05 Shin Nisseki Ekisho Film Kk Method for inspecting optical film
JP2009097915A (en) * 2007-10-15 2009-05-07 Nippon Oil Corp Inspection method of optical film
US20100157297A1 (en) * 2008-12-19 2010-06-24 Tae Man Kim Apparatus and method of testing liquid crystal display device
JP2013050393A (en) * 2011-08-31 2013-03-14 Fujifilm Corp Device and method for detecting defect of patterned retardation film, and method for manufacturing patterned retardation film
WO2016105017A1 (en) * 2014-12-23 2016-06-30 동우 화인켐 주식회사 Optical film and oled display device comprising same
JP2019070617A (en) * 2017-10-11 2019-05-09 住友化学株式会社 Defect inspection device, defect inspection method, and film manufacturing method
JP2019151099A (en) * 2018-03-02 2019-09-12 住友化学株式会社 Laminate film

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006003174A (en) * 2004-06-16 2006-01-05 Shin Nisseki Ekisho Film Kk Method for inspecting optical film
JP2009097915A (en) * 2007-10-15 2009-05-07 Nippon Oil Corp Inspection method of optical film
US20100157297A1 (en) * 2008-12-19 2010-06-24 Tae Man Kim Apparatus and method of testing liquid crystal display device
JP2013050393A (en) * 2011-08-31 2013-03-14 Fujifilm Corp Device and method for detecting defect of patterned retardation film, and method for manufacturing patterned retardation film
WO2016105017A1 (en) * 2014-12-23 2016-06-30 동우 화인켐 주식회사 Optical film and oled display device comprising same
JP2019070617A (en) * 2017-10-11 2019-05-09 住友化学株式会社 Defect inspection device, defect inspection method, and film manufacturing method
JP2019151099A (en) * 2018-03-02 2019-09-12 住友化学株式会社 Laminate film

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023189090A1 (en) * 2022-03-31 2023-10-05 住友化学株式会社 Test method

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