KR20190040905A - Defect inspection apparatus, defect inspection method, and manufacturing method for optical film - Google Patents

Abstract

According to one embodiment of the present invention, a defect inspection device (3A), as a defect inspection device of a film (100), has a light irradiation part (10A) for outputting an inspection light (L) to be irradiated to an inspection area (A) of the film, and an imaging part (20A) for imaging the inspection area, and at least one of the light irradiation part and the imaging part has a filter part (12) for selectively passing light in a predetermined polarization direction, wherein the filter part is configured to adjust the predetermined polarization direction.

Description

TECHNICAL FIELD [0001] The present invention relates to a defect inspection apparatus, a defect inspection method,

The present invention relates to a defect inspection apparatus, a defect inspection method, and a method of manufacturing a film.

There is known a defect inspection apparatus for detecting defects such as optical films such as polarizing films and retardation films, films used for separators of batteries, and the like. This type of defects inspection apparatus is a defect inspection apparatus in which a film is transported by a transport section, light is irradiated to a film inspection region by a light irradiating section, an inspection region of the film is sensed by an image pickup section, Inspection is performed. As a defect inspection apparatus, for example, an apparatus using an inspection optical system based on a positive transmission method (see Patent Document 1) and an apparatus using an inspection optical system based on Cross-Nicole transmission (refer to Patent Document 2) are known.

Patent Document 1: Japanese Patent Laid-Open Publication No. 1467975 Patent Document 2: Japanese Patent Application Laid-Open No. 2007-212442

In defect inspection, it is preferable to detect defects with a plurality of different inspection optical systems (e.g., positive transmission inspection optical system and Cross-Nicol inspection optical system) in order to more reliably detect defects. However, if these inspection optical systems are separately prepared, the introduction cost and the management cost become high, and integration of a plurality of inspection optical systems is required.

Therefore, it is an object of the present invention to provide a defect inspection apparatus, a defect inspection method, and a film production method which incorporate different inspection optical systems.

A defect inspection apparatus according to one aspect of the present invention is an apparatus for defect inspection of a film, comprising: a light irradiation section for outputting inspection light to be irradiated to an inspection region of the film; and an imaging section for imaging the inspection region, And at least one of the image pickup section and the image pickup section has a filter section for selectively passing light in a predetermined polarization direction, and the filter section is configured to adjust the predetermined polarization direction.

According to another aspect of the present invention, there is provided a defect inspection method for a film, comprising: an inspection light irradiation step of irradiating an inspection light onto an inspection area of the film with a light irradiation part; Wherein at least one of the light irradiation section and the imaging section has a filter section for selectively passing light in a predetermined polarization direction, and the filter section is configured to adjust the predetermined polarization direction.

In the defect inspection apparatus and the defect inspection method, an inspection region is imaged by an imaging section in a state in which inspection light is irradiated to a inspection region of a film by a light irradiation section. Therefore, the inspection unit can obtain the inspection image of the inspection area illuminated by the inspection light from the light irradiation unit. At least one of the light irradiation section and the imaging section has a filter section for selectively passing light in a predetermined polarization direction and the filter section is configured to be able to adjust the predetermined polarization direction. Therefore, it is possible to obtain inspection images of different inspection states by adjusting the predetermined polarization direction in the filter section. That is, in one defect inspection apparatus, it is possible to integrate another inspection optical system, and defect inspection in each of the different inspection optical systems is possible by adjusting the polarization direction of light selectively passed by the filter unit.

The filter unit in the defect inspection apparatus and the defect inspection method may have a liquid crystal filter in which a linear polarizing film is provided on one surface of a liquid crystal cell. In this case, the polarization direction of the light passing through the liquid crystal filter can be adjusted to a short time (for example, 0.1 msec to 25 msec) depending on whether or not the voltage is applied to the liquid crystal filter.

In the defect inspection apparatus according to an embodiment, the film may be an optical film having a linear polarization characteristic, and the light irradiation portion may have a light source and the filter portion disposed between the light source and the film. In the defect inspection method according to an embodiment, the film is an optical film having a linear polarization characteristic, and the light irradiating unit outputs the inspection light in the predetermined polarization direction by passing light from the light source through the filter unit And the predetermined polarizing direction of the inspection light may be adjusted by the filter unit in the inspection light irradiation step.

In this case, since the predetermined polarization direction of the inspection light is adjusted, defect inspection of the optical film having the linear polarization characteristic can be performed, for example, in a parallel Nicol state and also in a Cross Nicol state or a half cross Nicol state. In the present specification, the parallel Nicol state is a state in which two polarization directions (or polarization directions and polarization axes) are substantially parallel, that is, an angle formed by two polarization directions (or polarization directions and polarization axes) The angle of the two polarizing directions (or the polarization direction and the polarization axis) is substantially orthogonal. In other words, the cross-Nicol state is a state in which the angle is not less than 85 degrees and not more than 105 degrees , And the half cross Nicole state means a state in which the angle formed by the two polarization directions (or the polarization direction and the polarization axis) is greater than 1 DEG and less than 85 DEG.

In the defect inspection apparatus according to an embodiment, the film is an optical film having a linear polarization characteristic, and the light irradiation unit includes a light source, and a light source that converts the light from the light source into a first polarized light having a polarization direction orthogonal to the first polarized light, A second polarized light separating element which is disposed on an optical path of the second polarized light separated by the polarized light separating element and which separates the optical path of the first polarized light separated by the polarized light separating element into an optical path of the second polarized light An optical system for guiding the first polarized light separated by the polarized light separating element to the optical path combining section, and a filter section disposed on the optical path of the first polarized light guided by the optical system , The film is disposed on the optical path of the second polarized light, and the filter unit selectively transmits the first polarized light and the second polarized light It may be switched in the case of passing the.

In this configuration, the optical film has a linear polarization characteristic that allows the first polarized light to pass therethrough. When the filter unit selectively passes the first polarized light, after the output light from the light source is separated into the first polarized light and the second polarized light by the polarization splitting element, the optical path of the separated first polarized light and the second polarized light is Synthesized in the optical path synthesis section, and output toward the film to be inspected. Therefore, when the filter unit passes the first polarized light, the non-polarized inspection light is output from the light irradiation unit. Since the non-polarized inspection light contains the first polarized light, it is possible to inspect the optical film having the linear polarization characteristic in the parallel Nicol state. When the filter unit selectively passes the second polarized light, when the output light from the light source is separated into the first polarized light and the second polarized light by the polarization splitting element, the separated first polarized light is blocked at the filter unit. Therefore, only the second polarized light is output from the optical path combining section. Therefore, when the filter unit selectively passes the second polarized light, inspection light as the second polarized light is output from the light irradiation unit. Therefore, it is possible to inspect an optical film having a linear polarization characteristic in the cross-Nicol state.

The light irradiating unit is disposed between the polarized light separating element and the optical path combining section on the optical path of the second polarized light and is disposed in a crossed Nicols state with respect to the film, .

In the defect inspection apparatus according to an embodiment, the film may be an optical film having a linear polarization characteristic, and the imaging section may include a camera and the filter section disposed between the camera and the film. In the defect inspection method according to an embodiment, the film is an optical film having a linear polarization characteristic, and the imaging section images the inspection area of the film with a camera through the filter section, and in the imaging step, The predetermined polarization direction may be adjusted.

In this case, the arrangement relationship between the optical film having the linearly polarized light characteristic and the filter portion can be switched, for example, between the parallel Nicol state and the cross-Nicol state or the half-cross Nicol state by switching the polarization direction of the light passing through the filter unit. Thus, for example, defect inspection of an optical film having a linear polarization characteristic can be performed, for example, in a parallel Nicol state, and also in a Cross Nicol state or a Half Cross Nicol state.

The defect inspecting apparatus according to an embodiment further includes a first linear polarizing film disposed between the film and the imaging unit, the film having no linear polarization characteristic, the light irradiating unit including a light source, And the filter portion disposed between the light source and the film. In the defect inspection method according to an embodiment, the film is a film having no polarization characteristic, and the light irradiation unit outputs the inspection light in the predetermined polarization direction by passing light from the light source to the filter unit, Wherein in the inspection light irradiation step, the predetermined polarizing direction of the inspection light is switched by the filter unit, and in the imaging step, the imaging unit causes the first linear polarizing film disposed between the film and the imaging unit The inspection area may be picked up.

In this case, by changing the polarization direction of the light passing through the filter section, the first linearly polarizing film and the filter section form a parallel Nicol state, and a cross Nicol state or a half cross Nicol state can be formed. Therefore, even when the film does not have a linear polarization characteristic, it is possible to perform, for example, defect inspection in the parallel Nicol state and defect inspection in the cross-Nicol state or half cross Nicole state.

The defect inspecting apparatus according to an embodiment may further include a first linearly polarizing film disposed between the imaging unit and the film, wherein the film has no polarizing property, and the light irradiating unit includes a light source, And a polarized light separating element for separating light from the first polarized light into first polarized light and second polarized light whose polarization directions are orthogonal to each other and a second polarized light separating element disposed on the optical path of the second polarized light, An optical system for guiding the first polarized light separated by the polarized light separating element to the optical path combining section; and a second polarized light separating section for separating the polarized light separating element and the polarized light separating element from each other, A second linear polarizing film disposed between the optical path synthesizing sections and arranged in a crossed Nicols state with respect to the first linear polarizing film for allowing the second polarized light to pass therethrough, Wherein the film is disposed on the optical path of the second polarized light, and the filter unit is configured to selectively pass the first polarized light and the second polarized light, Or may be switched in the case of selectively passing two polarized light beams.

In this case as well, by switching the polarization direction of the light passing through the filter section, the first linearly polarizing film and the filter section form a parallel Nicol state, and a Cross Nicol state can be formed. Therefore, even when the film does not have a linear polarization characteristic, for example, the defect inspection in the parallel Nicol state and the defect inspection in the cross Nicol state can be performed.

The defect inspecting apparatus according to an embodiment may further include a first linear polarizing film disposed between the light irradiating unit and the film, wherein the film is a film having no polarization characteristic, and the imaging unit includes a camera, And the filter portion disposed between the films. In the defect inspection method according to an embodiment, the film is a film having no polarization characteristic, and the light irradiation unit outputs the inspection light in the predetermined polarization direction by passing light from the light source to the filter unit, And the inspection light is irradiated onto the optical film through the first linearly polarizing film disposed between the light irradiation part and the film in the inspection light irradiation step, And in the imaging step, the predetermined polarization direction through which the filter section passes may be adjusted.

In this case, by changing the polarization direction of the light passing through the filter section, the first linearly polarizing film and the filter section form a parallel Nicol state, and a cross Nicol state or a half cross Nicol state can be formed. Therefore, even when the film does not have a linear polarization characteristic, it is possible to perform, for example, defect inspection in the parallel Nicol state and defect inspection in the cross-Nicol state or half cross Nicole state.

The defect inspection apparatus according to one embodiment has two light irradiation portions and the first light irradiation portion which is one of the two light irradiation portions is disposed on the side opposite to the imaging portion as viewed from the film, And the second light irradiating portion, which is the other of the light irradiating portions, may be disposed on the same side as the imaging portion as viewed from the film.

In this case, the first light irradiation unit and the imaging unit constitute a transmission inspection optical system, and the second light irradiation unit and the imaging unit constitute a reflection inspection optical system. Therefore, in the above configuration, the transmission inspection optical system and the reflection inspection optical system are integrated.

Another aspect of the present invention relates to a method of manufacturing a film including a step of inspecting the film according to a defect inspection method of a substrate according to another aspect of the present invention.

INDUSTRIAL APPLICABILITY As described above, the present invention can provide a defect inspection apparatus, a defect inspection method and a film production method which incorporate different inspection optical systems.

1 is a schematic diagram of a defect inspection system including a defect inspection apparatus according to the first embodiment.
2 is a schematic diagram of a defect inspection apparatus according to the first embodiment. Part (a) of FIG. 2 shows a case where the liquid crystal filter (filter portion) of the defect inspection apparatus is in the OFF state. And the liquid crystal filter (filter portion) of the defect inspection apparatus is in an ON state.
3 is a schematic diagram of a defect inspection apparatus according to the second embodiment.
4 is a schematic diagram of a defect inspection apparatus according to the third embodiment.
5 is a schematic diagram of a defect inspection apparatus according to the fourth embodiment.
6 (a) is an inspection image in the regular reflection inspection optical system, and Fig. 6 (b) is an inspection image in the Cross-Nicol reflection inspection optical system It is a picture.
Fig. 7 shows the inspection image in the second inspection in the verification test. Fig. 7 (a) is the inspection image in the regular reflection inspection optical system, and Fig. 7 (b) It is a picture.
8 is a schematic diagram of a defect inspection apparatus according to the fifth embodiment.
9 is a schematic diagram of a defect inspection apparatus according to the sixth embodiment.
10 is a schematic diagram of a defect inspection apparatus according to the seventh embodiment.
11 is a schematic diagram of a defect inspection apparatus according to the eighth embodiment.
12 is a schematic diagram of a defect inspection apparatus according to the ninth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same elements are denoted by the same reference numerals, and redundant explanations are omitted. The dimensional ratios in the drawings do not necessarily coincide with those in the description.

(First Embodiment)

1 is a schematic diagram of a defect inspection system including a defect inspection apparatus according to the first embodiment. The defect inspection system 1 is provided with a transport section 2 and a defect inspection apparatus 3A. The defect inspection system 1 includes a transport path 2, In the defect inspection apparatus 3A arranged, defects of the optical film 100 are inspected.

The conveying section 2 has a conveying roller R. The carrying section 2 may be provided with a tension applying device for imparting tension to the optical film 100 to be carried, in addition to the carrying roller (R). In Fig. 1, XYZ Cartesian coordinates to be used are shown for convenience of explanation. The X direction represents the width direction of the optical film 100, and the Y direction represents the transport direction of the optical film 100. [ The Z direction indicates a direction orthogonal to each of the X direction and the Y direction. In the description of other drawings, the same X, Y, and Z rectangular coordinates may be used.

The defect inspection system 1 may be provided with a marking device 4 as shown in Fig. The marking device 4 is a device for sticking an eye mark M on the optical film 100 using defect information sent from the defect inspection device 3A. The marking apparatus 4 has, for example, an arm extending along the width direction X of the optical film 100, and a marker head having a pen or the like. The mark M is stuck on the optical film 100 by moving the arm head in the width direction X by the marker head. The marking apparatus 4 may be configured to be controlled by the defect inspection apparatus 3A or the marking apparatus 4 itself may have a control section called a computer. The marking apparatus 4 may also code defect information sent from the defect inspection apparatus 3A in a two-dimensional manner and print on the optical film 100. [

The defect inspection performed by the defect inspection apparatus 3A is a process for detecting a defect that may occur at the time of manufacturing the optical film 100 (including the transporting process) And a defect map indicating the position of the defect map. These defects include, for example, bubbles, foreign matter and whiteness mixed in the optical film 100 in the manufacturing process of the optical film 100, foreign matters attached to the optical film 100, and irregularities formed in the optical film 100 .

The defect inspection apparatus 3A according to the first embodiment will be described with reference to FIG. 2 (a) shows a case where the liquid crystal filter (filter portion) of the defect inspection apparatus 3A is in the OFF state, and Fig. 2 2 (b) shows that the liquid crystal filter (filter portion) of the defect inspection apparatus 3A is in an ON state.

In Fig. 2, a polarizing film having a linear polarization characteristic is exemplified as the optical film 100 to be inspected by the defect inspection apparatus 3A. In the following, the optical film 100 as a polarizing film is a laminate of a film body 101, a protective film 102, and a protective film 103 unless otherwise specified.

The film body 101 has a linear polarization characteristic. In the first embodiment, the polarization axis PA1 of the film body 101 is parallel to the Y direction, which is the transport direction of the optical film 100. [ An example of the material of the film body 101 is PVA (Polyvinyl Alcohol). The protective films 102 and 103 are bonded to both sides of the film main body 101. An example of the material of the protective films 102 and 103 is TAC (triacetyl cellulose).

The optical film 100 may further include films such as a protective film and a separate film on the side opposite to the side in contact with the film body 101 of each of the protective films 102 and 103. A film such as a protective film or a separate film can be bonded to the protective films 102 and 103 through, for example, a pressure-sensitive adhesive or an adhesive. Either one of the protective films 102 and 103 may be replaced with a film such as a separate film. An example of the material of the separate film and the protective film is PET (Polyethylene Terephthalate). The protective film and the separate film are peeled from the optical film 100 before and after bonding the optical film 100 to, for example, a liquid crystal panel or another optical film.

Hereinafter, the light polarized in the conveying direction (direction of the polarization axis PA1 of the film body 101) of the optical film 100 is referred to as a first polarized light, and the light polarized in a direction orthogonal to the first polarized light 2 polarized light.

The defect inspection apparatus 3A includes a light irradiation section 10A and an image pickup section 20A. The defect inspection apparatus 3A may include a light irradiation section 10A and a control device 30 for controlling the image pickup section 20A. Hereinafter, a configuration including the control device 30 will be described unless otherwise specified. The same is true in other embodiments.

The light irradiation portion 10A is disposed on the side opposite to the image pickup portion 20A as viewed from the optical film 100. [ The light irradiation unit 10A outputs the inspection light L to be irradiated to the optical film 100 to be inspected toward the inspection area A of the optical film 100 (see Fig. 1). The light irradiating section 10A has a light source 11 and a liquid crystal filter 12 and transmits the unpolarized light output from the light source 11 through the liquid crystal filter 12, (L). In Fig. 2, the polarization direction of the first polarized light is indicated by both arrows, and the polarization direction of the second polarized light is indicated by a black circle.

The light source 11 is not limited as long as it is unpolarized light and can output light that does not affect the composition and properties of the optical film 100. Examples of the light source 11 include a metal halide lamp, a halogen transmission light, a fluorescent lamp, and the like. The light source 11 can extend in the width direction of the optical film 100 as shown in Fig. Alternatively, the light irradiating unit 10A may include a plurality of light sources 11, which may be disposed discretely along the width direction of the optical film 100. [

In the first embodiment, the liquid crystal filter 12 selectively passes light in a predetermined polarization direction among the polarized lights included in the output light from the light source 11. [ The liquid crystal filter 12 is in an OFF state in a state in which a constant voltage is applied and in a state in which the constant voltage is not applied. By switching the ON / OFF state of the liquid crystal filter 12, the polarization direction of the light passing through the liquid crystal filter 12 is switched. The liquid crystal filter 12 is electrically connected to the control device 30 and is ON / OFF controlled by the control device 30. [ In the following description, unless otherwise stated, the adjustment of the predetermined polarization direction of the light passing through the liquid crystal filter 12 means the switching of the polarization direction between the first polarized light and the second polarized light which are orthogonal to each other. However, by controlling the voltage applied to the liquid crystal filter 12, the predetermined polarization direction can be adjusted.

The liquid crystal filter 12 has a linear polarizing film 12a and a liquid crystal cell 12b. The linear polarizing film 12a has a linear polarization characteristic. The liquid crystal cell 12b is formed by filling a liquid crystal material between a pair of glass plates arranged with a separator interposed therebetween. On the inner surfaces of the pair of glass plates, alignment films are formed in which alignment directions are orthogonal to each other.

The liquid crystal filter 12 is disposed between the polarization axis PA2 of the linear polarizing film 12a and the polarizing axis PA2 of the film main body 12a in the case where the linear polarizing film 12a forms the cross- 101 are arranged orthogonal to each other. Therefore, the direction of the polarization axis PA2 is a direction orthogonal to the paper surface. Therefore, in Fig. 2, the polarization axis PA2 is indicated by a black circle. The same is true in the other drawings.

The liquid crystal filter 12 is arranged so that the linear polarizing film 12a is positioned between the light source 11 and the optical film 100 on the light source 11 side. Therefore, when the output light of unpolarized light from the light source 11 is incident on the liquid crystal filter 12, only the second polarized light, which is the light having the polarization direction along the polarization axis PA2 of the linearly polarized light film 12a, 12a and enters the liquid crystal cell 12b.

When the liquid crystal filter 12 is in the OFF state, the second polarized light incident on the liquid crystal cell 12b rotates in the liquid crystal cell 12b in the polarization direction by 90 DEG, Similarly, the light is output as the first polarized light. That is, when the liquid crystal filter 12 is in the OFF state, the first polarized light selectively passes through the liquid crystal filter 12. On the other hand, when the liquid crystal filter 12 is in an ON state, a voltage is applied to the liquid crystal cell 12b. In this case, as shown in FIG. 2 (b), the second polarized light is output. That is, when the liquid crystal filter 12 is in the ON state, the second polarized light selectively passes through the liquid crystal filter 12.

Therefore, the light irradiating unit 10A switches the inspection light L as the first polarized light and the inspection light L as the second polarized light by controlling ON / OFF of the liquid crystal filter 12, As shown in Fig.

The arrangement relationship of the liquid crystal filter 12 and the optical film 100 shown in Fig. 2 is such that when the optical film 100 is bonded to the liquid crystal cell 12b of the liquid crystal filter 12, .

The imaging section 20A has at least one camera 21 for imaging the optical film 100. [ In Fig. 1, the image pickup section 20A exemplifies a form having a plurality of cameras 21 arranged along the width direction of the optical film 100. Fig. The camera 21 is an area sensor camera called a CCD camera. The camera 21 may be a line sensor camera. When the camera 21 is a line sensor camera, it is possible to capture the inspection area A of the optical film 100 by moving the camera 21 and the optical film 100 relatively. The imaging section 20A (specifically, the camera 21) is electrically connected to the control device 30, and the imaging timing is controlled, and the obtained imaging data is input to the control device 30. [

The control device 30 controls the light irradiation unit 10A and the image pickup unit 20A. The control device 30 controls the light output timing of the light source 11 to be controlled by the control device 30. The control device 30 controls the liquid crystal filter 12 and the camera 21 in the first embodiment, . The control device 30 has, for example, a computer (operation unit). The control device 30 has a function of performing image processing such as detecting a defective portion and highlighting a defective portion with respect to the image pickup data input from the image pickup portion 20, A function of creating a defect map indicating a defect position, and the like. 1, the defect inspection system 1 includes a marking device 4, and the control device 30 is electrically connected to the marking device 4 as shown in FIG. 1 , The marking device 4 may be controlled to give the mark M based on the detected defect information to the optical film 100. [

Next, a method of inspecting the optical film 100 using the defect inspection apparatus 3A will be described. When defect inspection is performed, inspection light L of a predetermined polarization state (predetermined polarization direction) is irradiated from the light irradiation unit 10A to the inspection area A of the optical film 100 (inspection light irradiation step) . When the inspection light L is irradiated onto the optical film 100 in the inspection light irradiation process, the inspection area A is imaged by the imaging unit 20A (more specifically, the camera 21) (imaging process).

In the inspection light irradiation step, the predetermined polarization state of the inspection light L is switched by ON / OFF controlling the liquid crystal filter 12. [ Concretely, for example, first, the liquid crystal filter 12 is set in the OFF state, and the inspection light L, which is the first polarized light, is irradiated onto the optical film 100. Thereafter, the liquid crystal filter 12 is set to the ON state, and the inspection light L which is the second polarized light is irradiated onto the optical film 100. The liquid crystal filter 12 may be set in the ON state and thereafter turned OFF.

In the imaging step, the imaging unit 20A picks up the inspection area A in synchronization with the switching of the predetermined polarization state of the inspection light L.

In the defect inspection method, when the inspection light L which is the first polarized light in the inspection light irradiation process is irradiated to the optical film 100, the inspection light L and the optical film 100 are in a parallel Nicol state, The inspection light L is incident on the optical film 100 with the polarization direction of the light L substantially coinciding with the direction of the polarization axis PA1 of the film body 101 of the optical film 100 . On the other hand, when the inspection light L which is the second polarized light is irradiated on the optical film 100 in the inspection light irradiation process, the inspection light L and the optical film 100 are in the crossed Nicols state, The inspection light L is incident on the optical film 100 in a state in which the polarization direction and the polarization axis PA1 are substantially orthogonal to each other.

Therefore, by inspecting the inspection area A in the image sensing unit 20A in synchronization with the switching of the predetermined polarization direction of light to be passed by the liquid crystal filter 12, An inspection image in the case where the optical film 100 is illuminated in each of the light L (parallel Nicol light) and the cross-Nicol state inspection light L (Cross Nicol light) is obtained in the imaging step.

Next, a method of manufacturing the optical film 100 including a defect inspection method using the defect inspection apparatus 3A shown in Figs. 1 and 2 will be described. Here, the case of manufacturing the optical film 100 as the lamination of the protective film 102, the film body 101 and the protective film 103 will be described as an example.

When the optical film 100 is manufactured, the strip-shaped film body 101, the strip-shaped protective film 102, and the strip-shaped protective film 103 are transported in the longitudinal direction, , And the protective film 103 is bonded to the other surface of the protective film 102 (bonding step). The bonding of the film main body 101 to the protective film 102 and the protective film 103 can be performed using, for example, a pair of bonding rollers. The bonding step may be carried out by bonding the protective film 102 and the protective film 103 to the film main body 101 at the same time and attaching one of the protective film 102 and the protective film 103 to the film main body 101 The other side may be joined.

After the bonding step, the optical film 100 as a laminate of the protective film 103, the film body 101 and the protective film 102 is irradiated to the light irradiation section 10A and the image pickup section 10A in the defect inspection apparatus 3A 20A, the defect inspection apparatus 3A performs defect inspection of the optical film 100 (defect inspection step). In the defect inspection step, the defect inspection of the optical film 100 is performed by the defect inspection method described above. In the case where the defect inspection system 1 is provided with the marking device 4, the defect inspection process is carried out by the marking device 4 with the mark M being provided to the optical film 100 ) May be performed.

In the above manufacturing method, the defect inspection was performed on the optical film 100 as the laminated body of the protective film 103, the film body 101 and the protective film 102 by the defect inspection apparatus 3A. However, the film body 101 before the protective film 103 and the protective film 102 are bonded may be subjected to defect inspection by the defect inspection apparatus 3A as an optical film.

In the defect inspection method using the defect inspection device 3A and the defect inspection device 3A, the ON / OFF control of the liquid crystal filter 12 allows the defect of the optical film 100 It is possible to obtain a checked image and a checked image of the optical film 100 by irradiation in the crossed Nicol state.

Therefore, the defect inspection apparatus 3A is configured so that the transmission inspection optical system by parallel Nicol (hereinafter referred to as "positive transmission inspection optical system") and the transmission inspection optical system by Cross Nicol (hereinafter referred to as cross Nicol transmission inspection optical system) Lt; / RTI > The defect may be detected only in one of the positive transmission inspection optical system and the Cross-Nicol transmission inspection optical system depending on the kind thereof. It is easy to reliably detect defects in the optical film 100 if the positive transmission inspection optical system and the Cross Nicole transmission inspection optical system are integrated into one apparatus as in the defect inspection apparatus 3A.

Further, in the case of a defect which can be detected by either the positive transmission inspection optical system or the cross-Nicoll transmission inspection optical system, for example, when a defect which has been caused by the positive transmission inspection optical system does not appear in the inspection image of the cross- It can be judged that the defect occurs on the image side (on the image pickup unit 20A side) rather than the film body 101. [ That is, it is possible to identify the defect-generating layer in the optical film 100. Therefore, in the method of manufacturing the optical film 100 having the defect inspection method, it is easy to manufacture the optical film 100 as a product that does not contain defects.

The defect inspection apparatus 3A can switch the defect inspection in the positive transmission inspection optical system and the defect inspection in the Cross Nicole transmission inspection optical system to the ON / OFF control of the liquid crystal filter 12. [ Since the switching of the liquid crystal filter 12 can be performed for a shorter time (for example, 0.1 msec to 25 msec), defect inspection in two inspection optical systems can be efficiently performed. Therefore, in the method of manufacturing the optical film 100 including the defect inspection method, the optical film 100 as a product that does not contain defects can be efficiently produced.

(Second Embodiment)

In the first embodiment, the light irradiating portion is provided with a liquid crystal filter (filter portion), and the liquid crystal filter is disposed below the optical film 100. [ However, as shown in Fig. 3, the defect inspection apparatus may include a liquid crystal filter in the image pickup section.

3 is a schematic diagram of a defect inspection apparatus 3B according to the second embodiment. The defect inspection apparatus 3B has a light irradiation section 10B and an image pickup section 20B. In Fig. 3, an example of an optical path of light is schematically shown by an arrow of a one-dot chain line.

The light irradiation unit 10B is different from the light irradiation unit 10A of the first embodiment in that it does not have the liquid crystal filter 12. [ The configuration of the light source 11 included in the light irradiation unit 10B is the same as that in the first embodiment.

The image pickup section 20B is different from the image pickup section 20A of the first embodiment in that the image pickup section 20B has the liquid crystal filter 12 disposed between the camera 21 and the optical film 100. [ The configuration of the camera 21 is the same as that in the first embodiment. The camera 21 is electrically connected to the control device 30 and is controlled by the control device 30 as in the first embodiment.

The configuration of the liquid crystal filter 12 included in the image pickup section 20B is the same as that in the first embodiment. The liquid crystal filter 12 is electrically connected to the control device 30 and is ON / OFF controlled by the control device 30. [

The liquid crystal filter 12 is arranged such that the linear polarization film 12a is located on the image pickup section 20B side and the polarization axis PA2 of the linearly polarizing film 12a and the polarization axis PA1 of the film body 101 are in the cross- As shown in Fig. In this arrangement, light enters the liquid crystal filter 12 from the liquid crystal cell 12b side. Therefore, when the liquid crystal filter 12 is in the OFF state, the liquid crystal filter 12 selectively passes the first polarized light having the polarization direction orthogonal to the polarization axis PA2 of the linear polarizing film 12a. However, the first polarized light incident on the liquid crystal filter 12 rotates the polarization direction by 90 degrees while passing through the liquid crystal cell 12b, and is output as the second polarized light. On the other hand, when the liquid crystal filter 12 is in the ON state, the liquid crystal filter 12 selectively passes the second polarized light. When the liquid crystal filter 12 is in the ON state, the second polarized light incident on the liquid crystal filter 12 is outputted from the liquid crystal filter 12 while maintaining the polarization direction thereof.

Next, a method of inspecting defects of the optical film 100 using the defect inspection apparatus 3B will be described. The output light of unpolarized light from the light irradiation part 10B is irradiated to the inspection area A of the optical film 100 as the inspection light L (inspection light irradiation step). When the inspection light L is irradiated onto the optical film 100 in the inspection light irradiation process, the inspection area A is imaged by the imaging unit 20B (more specifically, the camera 21) (imaging process). More specifically, the optical film 100 is picked up by the camera 21 through the liquid crystal filter 12. In the imaging step, the optical film 100 is picked up by the camera 21 in synchronization with the ON / OFF control of the liquid crystal filter 12 to obtain a checked image when the liquid crystal filter 12 is in the ON state, 12 are in the OFF state.

Similarly to the case of the first embodiment, the defect inspection apparatus 3B is an apparatus in which a positive transmission inspection optical system and a Cross-Nicoll transmission inspection optical system are integrated. This point will be explained. For convenience of explanation, first, it is assumed that the optical film 100 has no defect.

In the inspection light irradiation step, the inspection light (L), which is unpolarized light, is irradiated onto the optical film (100). Since the film body 101 of the optical film 100 has the polarization axis PA1, the first polarized light included in the inspection light L is output from the optical film 100 and is incident on the liquid crystal filter 12 .

When the liquid crystal filter 12 is in the OFF state, the first polarized light from the optical film 100 passes through the liquid crystal filter 12 as described above, is converted into the second polarized light in the passing process, And is output as second polarized light. The second polarized light output from the liquid crystal filter 12 is received by the camera 21. Therefore, when the liquid crystal filter 12 is in the OFF state, a transmission image of the optical film 100 is obtained. That is, when the liquid crystal filter 12 is set in the OFF state, the inspection optical system of the defect inspection apparatus 3B functions as a positive transmission inspection optical system.

On the other hand, when the liquid crystal filter 12 is ON, since the liquid crystal filter 12 selectively passes the second polarized light as described above, the first polarized light from the optical film 100 passes through the liquid crystal filter 12, (12). In other words, the liquid crystal filter 12 in the ON state functions as a polarizing filter disposed in the cross-Nicol state with respect to the optical film 100. [ That is, when the liquid crystal filter 12 is set in the ON state, the inspection optical system of the defect inspection apparatus 3B functions as a cross-Nicol penetration inspection optical system.

Therefore, the defect inspection apparatus 3B is also an apparatus in which a positive transmission inspection optical system and a Cross-Nicoll transmission inspection optical system are integrated.

When a defect is included in the optical film 100 when the defect inspection apparatus 3B is made to function as a positive transmission inspection optical system, light is blocked by a defect or a polarization state is caused in a defect portion, And the defective portion appears as a dark region, for example.

On the other hand, when the defect inspection apparatus 3B functions as a cross-Nicol penetration inspection optical system, if there is no defect above the film main body 101 (on the imaging section 20B side) of the optical film 100, As described above, since the first polarized light is outputted from the optical film 100, the inspection image becomes a substantially dark image. If there is a defect on the upper side (on the imaging unit 20B side) of the optical film 100 than the film main body 101, the polarization state of the first polarized light from the film main body 101 is defective, The output light from the optical film 100 includes the second polarized light. Since the second polarized light can pass through the liquid crystal filter 12 in the ON state, light is incident on the camera 21. Therefore, defects appear as bright spots in the inspection image.

The defect inspection apparatus 3B is also an apparatus in which a positive transmission inspection optical system and a Cross Nicole transmission inspection optical system are integrated. The positive transmission inspection optical system and the Cross-Nicol transmission inspection optical system are switched to ON / OFF control of the liquid crystal filter 12 do. Therefore, the defect inspection apparatus 3B also has the same operational effects as the defect inspection apparatus 3A of the first embodiment.

Further, in the case of a defect which can be detected in either of the positive transmittance inspection optical system and the Cross-Nicol penetration inspection optical system, for example, in the case where a defect shown by the positive transmission inspection optical system does not appear in the inspection image of the Cross Nicol penetration inspection optical system, It can be judged that the defect occurs on the image side (on the image pickup unit 20A side) rather than the film body 101. [ That is, also in the defect inspection apparatus 3B, it is possible to identify the defect occurrence layer in the optical film 100. [

The defect inspection apparatus 3B can be applied to the defect inspection system 1 shown in Fig. 1 instead of the defect inspection apparatus 3A. Therefore, the manufacturing method of the optical film 100 including the defect inspection method using the defect inspection apparatus 3B has the same operational effects as those of the first embodiment.

(Third Embodiment)

4 is a schematic diagram of a defect inspection apparatus 3C according to the third embodiment. Also in Fig. 4, the optical path of light is schematically shown by a one-dot chain line.

The defect inspection apparatus 3C shown in Fig. 4 differs from the defect inspection apparatus 3C of the first embodiment in that the defect inspection apparatus 3C shown in the first embodiment is provided with the imaging section 20B described in the second embodiment in place of the imaging section 20A. Which is different from the device 3A. The liquid crystal filter 12 of the light irradiating unit 10A and the liquid crystal filter 12 and the camera 21 of the image pickup unit 20B are connected to the control device 30 in the same manner as in the first and second embodiments And is controlled by the control device 30. [

A method of inspecting defects of the optical film 100 using the defect inspection apparatus 3C will be described. The inspection light L is irradiated from the light irradiation unit 10A to the inspection area A (see FIG. 1) of the optical film 100 (inspection light irradiation step). When the inspection light L is irradiated onto the optical film 100 in the inspection light irradiation process, the inspection area A is imaged by the imaging unit 20B (more specifically, the camera 21) (imaging process).

In the inspection light irradiation step, the liquid crystal filter 12 of the light irradiation portion 10A is turned ON / OFF to control the predetermined polarized state (predetermined polarization direction) of the inspection light L, . In the imaging step, the ON / OFF control of the liquid crystal filter 12 included in the imaging unit 20B is performed in accordance with the ON / OFF control of the liquid crystal filter 12 of the light irradiation unit 10A to control the light irradiation unit 10A, The inspection image is obtained in accordance with the combination of the ON state and the OFF state of the liquid crystal filter 12 of each of the liquid crystal display elements 20A and 20B.

Specifically, when the liquid crystal filter 12 of the light irradiating unit 10A is set to the OFF state, the liquid crystal filter 12 of the image sensing unit 20B is ON / OFF-controlled, And obtains inspection images when the liquid crystal filter 12 is set in the OFF state and the ON state, respectively. OFF control of the liquid crystal filter 12 of the image pickup section 20B when the liquid crystal filter 12 of the light irradiating section 10A is set to the ON state and the liquid crystal filter 12 ) Is set to the OFF state and the ON state, the inspection image is obtained, respectively. Therefore, in the defect inspection apparatus 3C, the inspection image corresponding to the cases (a) to (d) shown in Table 1 is obtained.

In the case (a), inspection light L in a parallel Nicol state is irradiated on the optical film 100, so that the first polarized light is output from the optical film 100. The first polarized light can pass through the liquid crystal filter 12 in the case (a) as described in the second embodiment. Therefore, the inspection optical system in Case (a) corresponds to the positive transmission inspection optical system.

In the case (b), similarly to the case (a), the first polarized light is output from the optical film (100). In the case (b), since the liquid crystal filter 12 of the image pickup section 20B is set in the ON state, when there is no defect in the optical film 100 (more specifically, Light does not pass through the liquid crystal filter 12 of the image pickup unit 20B. Therefore, the case (b) corresponds to the Cross-Nicol penetration inspection optical system.

In the case (c) and the case (d), since the inspection light (L) in the crossed Nicol state is irradiated on the optical film (100), it corresponds to the crossed Nicol penetration inspection optical system.

As described above, also in the defect inspection apparatus 3C, the positive transmission inspection optical system and the cross-Nicoll transmission inspection optical system are integrated, and the two optical systems are switched to the ON / OFF control of the liquid crystal filter 12. [ Therefore, the defect inspection method using the defect inspection apparatus 3C and the defect inspection apparatus 3C has the same operational effects as the defect inspection apparatus 3A according to the first embodiment.

The defect inspection apparatus 3C can be applied to the defect inspection system 1 shown in Fig. 1 instead of the defect inspection apparatus 3A. Therefore, the manufacturing method of the optical film 100 including the defect inspection method using the defect inspection apparatus 3B has the same operational effects as those of the first embodiment. The defect inspection apparatus 3C can perform the defect inspection of the optical film 100 in each of the four cases of the case (a) to the case (d), so that it is easy to perform the inspection according to the optical film 100 .

(Fourth Embodiment)

The defect inspection apparatuses 3A, 3B, and 3C described in the first to third embodiments employ a transmission inspection optical system. However, as schematically shown in Fig. 5, the defect inspection apparatus may employ a reflection inspection optical system. 5 is a schematic diagram of a defect inspection apparatus 3D according to the fourth embodiment. 5 also schematically shows an example of an optical path of light by a one-dot chain line.

The defect inspection apparatus 3D is similar to the defect inspection apparatus 3A of the first embodiment in that the light irradiation section 10A and the imaging section 20A are disposed on the same side of the optical film 100 to be inspected ). In other words, in the defect inspection apparatus 3D, in the defect inspection apparatus 3A of the first embodiment, when the inspection light L from the light irradiation unit 10A is reflected by the optical film 100, And the light irradiation unit 10A and the image pickup unit 20A are arranged so that the reflected light enters the image pickup unit 20A. The configuration of the light irradiation section 10A and the imaging section 20A is the same as that of the first embodiment and the defect inspection method of the optical film 100 using the defect inspection apparatus 3D is the same as that of the first embodiment.

Since the defect inspection apparatus 3D employs the reflection inspection optical system, the inspection light L in the parallel Nicol state with respect to the optical film 100 is detected by the ON / OFF control of the liquid crystal filter 12, (Parallel Nicol light) is irradiated onto the optical film 100 and the inspection light L (Cross Nicol light) in the cross-Nicol state with respect to the optical film 100 are irradiated to the optical film 100 A reflection inspection image can be obtained. Therefore, the defect inspection apparatus 3D is constructed by integrating a reflection inspection optical system in a parallel Nicol state (hereinafter referred to as a "regular reflection inspection optical system") and a reflection inspection optical system in a Cross-Nicol state (hereinafter referred to as a Cross-Nicol reflection inspection optical system) have. Further, the regular reflection inspection optical system and the Cross-Nicol reflection inspection optical system are switched by ON / OFF control of the liquid crystal filter 12. Therefore, the defect inspection method of the optical film 100 using the defect inspection apparatus 3D and the defect inspection apparatus 3D has the same operational effects as those of the first embodiment.

The defect inspection apparatus 3D employs a reflection inspection optical system as described above. When the inspection light L from the light irradiation unit 10A is the first polarized light, the inspection light L can propagate to the lower side of the film body 101 (the protective film 103 in Fig. 5). Therefore, in the regular reflection inspection optical system, it is also possible to detect defects included in the lower side of the film body 101. Conversely, when the inspection light L from the light irradiating unit 10A is the second polarized light, the inspection light L can not propagate below the film main body 101. [ Thus, in the Cross-Nicol reflection inspection optical system, defects located on the upper side of the film body 101 and the film body 101 can be inspected, but the defect on the lower side of the film body 101 can not be detected. Therefore, in the defect inspection apparatus 3D, the position of the defect in the thickness direction of the optical film 100 can also be specified by switching the inspection to the regular reflection inspection optical system and the inspection to the Cross-Nicol reflection inspection optical system .

Specifically, if defects can be detected by the inspection using the regular reflection inspection optical system and the Cross-Nicole reflection inspection optical system, the defects are located above the film body 101 and the film body 101. Conversely, if a defect is detected in the regular reflection inspection optical system, but the defect is not detected in the Cross-Nicol reflection inspection optical system, the defect is located below the film body 101. As described above, in the defect inspection apparatus 3D, the position of the defect can be identified in more detail. An experiment (verification experiment) that verifies this point will be described. In the description of the verification experiment, elements corresponding to constituent elements in the above description are denoted by the same reference numerals.

[Verification experiment]

The optical film 100 used in the verification test was a film in which the protective film 103, the film body 101, and the protective film 102 were laminated in this order. The material of the protective films 102 and 103 was TAC, and the material of the film body 101 was PVA. In the optical film 100 used for the verification test, a film in which air bubbles were incorporated on the protective film 102 side was used.

In the verification test, a defect inspection apparatus 3D having the configuration shown in Fig. 5 was used. However, a line sensor camera was used for the camera 21, and a line sensor camera and the optical film 100 were relatively moved to obtain a test image of the optical film 100. [

(First inspection)

In the first inspection, the optical film 100 is set on the defect inspection apparatus 3D so that the protective film 102 side is located on the side of the light irradiation unit 10A and the image pickup unit 20A, and the liquid crystal filter 12 OFF state and the ON state, thereby obtaining a test image of the optical film 100 with the regular reflection inspection optical system and the Cross-Nicol reflection inspection optical system. Fig. 6 shows the inspection image in the first inspection. Fig. 6 (a) is the inspection image in the regular reflection inspection optical system, and Fig. 6 (b) is the inspection image in the Cross-Nicol reflection inspection optical system.

(Second inspection)

In the second inspection, the optical film 100 is set in the defect inspection apparatus 3D with the optical film 100 turned upside down in the case of the first inspection. That is, the optical film 100 was set in the defect inspection apparatus 3D such that the side of the protective film 102 was positioned on the side opposite to the light irradiation section 10A and the image pickup section 20A. Then, similarly to the case of the first inspection, the inspection image of the optical film 100 was obtained with the regular reflection inspection optical system and the Cross-Nicol reflection inspection optical system. Fig. 7 shows the inspection image in the second inspection. Fig. 7 (a) is the inspection image in the specular reflection inspection optical system, and Fig. 7 (b) is the inspection image in the Cross-Nicol reflection inspection optical system. In the portions (a) and (b) of Fig. 7, the regions indicated by the dashed lines are areas corresponding to each other.

In the first inspection, bubble defects can be confirmed in either the inspection of the specular reflection inspection optical system or the inspection of the Cross-Nicol reflection inspection optical system. In this case, as described above, it is assumed that the defect is located on the upper side of the film body 101. In the first inspection, since the protective film 102 including bubble defects is located on the side of the light irradiation portion 10A and the imaging portion 20A side of the film body 101, Can coincide with what can be determined from the inspected image.

In the second inspection, in the inspection by the regular reflection inspection optical system, bubble defects could be confirmed in the area surrounded by the dot-dash line in part (a) of FIG. 7, while in the inspection of the Cross- Bubble defects could not be confirmed in the area enclosed by the one-dot chain line. In this case, it is presumed that the defect is located below the film body 101 as described above. In the second inspection, since the protective film 102 including the bubble defect is located on the side opposite to the light irradiation section 10A and the image pickup section 20A with respect to the film body 101, It can be understood that the defect position agrees with what can be judged from the inspection image.

Therefore, by comparing the results of defect inspection in each of the regular reflection inspection optical system and the Cross-Nicol reflection inspection optical system in the defect inspection apparatus 3D, it is possible to specify the position of the defect more specifically.

The defect inspection apparatus 3D can be applied to the defect inspection system 1 shown in Fig. 1 instead of the defect inspection apparatus 3D. Therefore, the manufacturing method of the optical film 100 including the defect inspection method using the defect inspection apparatus 3D has the same operational effects as those of the first embodiment.

(Fifth Embodiment)

8 is a schematic diagram of a defect inspection apparatus 3E according to the fifth embodiment. The defect inspection apparatus 3E is different from the defect inspection apparatus 3A of the first embodiment in that the defect inspection apparatus 3E includes the first light irradiation unit 10A1 and the second light irradiation unit 10A2. In Fig. 8, an example of the optical path of light is schematically shown by a one-dot chain line.

The first light irradiation portion 10A1 is disposed on the side opposite to the image pickup portion 20A as seen from the optical film 100 and obliquely enters the optical film 100 with the inspection light L. The configuration of the first light irradiation portion 10A1 is the same as the configuration of the light irradiation portion 10A of the first embodiment except that the first light irradiation portion 10A1 is arranged such that the inspection light L is obliquely incident, Do.

The second light irradiation portion 10A2 has the same configuration and arrangement as the light irradiation portion 10A described in the fourth embodiment. That is, the second light irradiation part 10A2 is arranged with respect to the optical film 100 so as to constitute a reflection inspection optical system together with the image pickup part 20A. The second light irradiating unit 10A2 is configured so that light output from the optical film 100 based on the inspection light L from each of the first light irradiation unit 10A1 and the second light irradiation unit 10A2 is reflected by the imaging unit 20A Or may be arranged so as to be incident on another area.

The control device 30 is electrically connected to the liquid crystal filter 12 of each of the first light irradiation part 10A1 and the second light irradiation part 10A2 and the first light irradiation part 10A1 and the second light irradiation part 10A2 ) ON / OFF control of each liquid crystal filter 12.

Next, a defect inspection method of the optical film 100 using the defect inspection apparatus 3E will be described. The light output from the optical film 100 based on the inspection light L from each of the first light irradiation portion 10A1 and the second light irradiation portion 10A2 is reflected by the camera 21 of the imaging portion 20A, The light is incident on the same area of the light receiving surface of the light receiving surface.

The inspection light L is irradiated from the first light irradiation part 10A1 to the inspection area A (see Fig. 1) of the optical film 100 and the second light irradiation part 10A2 is inspected The light L is irradiated to the inspection area A of the optical film 100 (inspection light irradiation step). When the inspection light L is irradiated onto the optical film 100 in the inspection light irradiation process, the optical film 100 is picked up by the imaging unit 20A (imaging process).

In the inspection light irradiation step, inspection light L is irradiated onto the inspection area A of the optical film 100 at different timings from the first light irradiation part 10A1 and the second light irradiation part 10A2. When the inspection light L is output from each of the first light irradiation unit 10A1 and the second light irradiation unit 10A2, the light irradiation unit (first light irradiation unit 10A1 or second (The light irradiating unit 10A2) turns on / off the liquid crystal filter 12 to switch the predetermined polarization state of the inspection light L.

For example, when the inspection light L is outputted from the first light irradiation part 10A1, the liquid crystal filter 12 of the first light irradiation part 10A1 is set to the OFF state, and the inspection light L, which is the first polarized light, The optical film 100 is irradiated. Subsequently, the liquid crystal filter 12 of the first light irradiation part 10A1 is set to the ON state to irradiate the inspection light L, which is the second polarized light, to the optical film 100. [ When the inspection light L is outputted from the second light irradiation part 10A2, the liquid crystal filter 12 of the second light irradiation part 10A2 is ON / OFF-controlled similarly to the case of the first light irradiation part 10A1 .

In the imaging step, the camera 21 of the imaging unit 20A controls the optical film (not shown) in synchronization with the ON / OFF control of the liquid crystal filter 12 at the time of outputting the inspection light L from the first light irradiation unit 10A1 100 in the inspection area A. Similarly, in synchronization with the ON / OFF control of the liquid crystal filter 12 at the time of outputting the inspection light L from the second light irradiation section 10A2, the optical film 100 is irradiated with the camera 21 of the imaging section 20A, The image of the inspection area A is picked up.

The light output from the optical film 100 based on the inspection light L from each of the first light irradiation unit 10A1 and the second light irradiation unit 10A2 is received by the camera 21 of the image pickup unit 20A The defect inspection method in the case where the surface is incident on a different region will be described. Also in this case, the inspection light irradiation step and the imaging step are included.

However, in the inspection light irradiation step, inspection light L may be output from the first light irradiation part 10A1 and the second light irradiation part 10A2 at the same timing. Then, the liquid crystal filter 12 of each of the first light irradiation part 10A1 and the second light irradiation part 10A2 is ON / OFF controlled. The ON / OFF control of the liquid crystal filter 12 of the first light irradiation part 10A1 and the ON / OFF control of the liquid crystal filter 12 of the second light irradiation part 10A2 may be the same or different.

In the image pickup step, the camera 21 of the image pickup section 20A, in synchronization with the ON / OFF control timing of the liquid crystal filter 12 of each of the first light irradiation section 10A1 and the second light irradiation section 10A2, (A) of the inspection object (100).

In the defect inspection apparatus 3E, the first light irradiation unit 10A1 and the image pickup unit 20A constitute the transmission inspection optical system described in the first embodiment. Therefore, in the defect inspection apparatus 3E and the defect inspection apparatus 3E, defect inspection using the first light irradiation section 10A1 has the same operational effects as those of the defect inspection apparatus 3A described in the first embodiment.

In the defect inspection apparatus 3E, the second light irradiation unit 10A2 and the image pickup unit 20A constitute the reflection inspection optical system described in the fourth embodiment. Therefore, in the defect inspection apparatus 3E and the defect inspection apparatus 3E, the defect inspection using the second light irradiation unit 10A2 has the same operational effects as the defect inspection apparatus 3E described in the fourth embodiment.

Further, in the defect inspection apparatus 3E, a transmission inspection optical system and a reflection inspection optical system are integrated. Therefore, defects that can be detected by the transmission inspection optical system and defects that can be detected by the reflection inspection optical system can be detected by a single device, and defects of the optical film 100 can be detected more reliably.

The defect inspection apparatus 3E can be applied to the defect inspection system 1 shown in Fig. 1 instead of the defect inspection apparatus 3A. Therefore, the manufacturing method of the optical film 100 including the defect inspection method using the defect inspection apparatus 3E has the same operational effects as those of the first embodiment.

(Sixth Embodiment)

FIG. 9 is a schematic diagram of a defect inspection apparatus 3F according to the sixth embodiment. The defect inspection apparatus 3F differs from the defect inspection apparatus 3A of the first embodiment in that the defect inspection apparatus 3F includes the light irradiation unit 10C instead of the light irradiation unit 10A. 9 also schematically shows the optical path of the light by a one-dot chain line.

The light irradiation unit 10C includes a light source 11, a polarization separation element 13, an optical path composition unit 14, a first mirror 15A, a second mirror 15B, a linear polarization film 16, And a liquid crystal filter (12). The configuration of the light source 11 and the configuration of the liquid crystal filter 12 are the same as those of the first embodiment.

The polarization separation element 13 is disposed on the optical path of the output light from the light source 11 and converts the output light of unpolarized light from the light source 11 into the first polarized light and the second polarized light, And is separated into light. Specifically, it transmits the second polarized light and reflects the first polarized light. An example of the polarization beam splitter 13 is an element using an APF (Advanced Polarizing Film), and is, for example, an element in which an APF is formed on one side of a prism, a glass plate or the like.

The optical path combining section 14 is disposed on the optical path of the second polarized light. Specifically, it is disposed between the polarization separation element 13 and the optical film 100 in the Z direction. The optical path synthesizing section 14 is an optical element that synthesizes the optical path of the first polarized light separated by the polarized light separating element 13 to the optical path of the second polarized light and outputs it. The optical path synthesizing section 14 outputs the first polarized light and the second polarized light to the optical film 100 side in a state in which the optical paths of the first polarized light and the second polarized light coincide with each other. An example of the optical path combining section 14 is the same as that of the polarization splitting element 13. [

The first mirror 15A and the second mirror 15B constitute an optical system for guiding the first polarized light separated by the polarization splitting element 13 to the optical path combining section 14. [ Specifically, the first mirror 15A is disposed on the side of the polarization splitting element 13 and reflects the first polarized light from the polarization splitting element 13 to the optical film 100 side. The second mirror 15B is disposed on the side of the optical path combining section 14 as the optical path of the first polarized light reflected by the first mirror 15A and is disposed on the side of the optical path combining section 14, And reflects the light to the optical path combining section 14 side.

The linearly polarizing film 16 is an optical film having a linearly polarizing characteristic. The linearly polarizing film 16 is disposed between the polarized light separating element 13 and the optical path combining section 14 and disposed on the optical path of the second polarized light. The linearly polarizing film 16 is arranged such that the polarization axis PA3 of the linear polarizing film 16 is in a crossed Nicol state with the optical film 100, that is, in the Z direction, the polarization axis PA1 of the film body 101, 16 are orthogonal to each other.

The liquid crystal filter 12 is disposed between the first mirror 15A and the second mirror 15B on the optical path of the first polarized light. The liquid crystal filter 12 is arranged so that the linear polarization film 12a is located on the second mirror 15B side and the polarization axis PA2 of the linearly polarizing film 12a is in a state of being parallel to the optical film 100 . In this arrangement, when the liquid crystal filter 12 is in the ON state, the liquid crystal filter 12 allows the first polarized light to pass therethrough. On the other hand, when the liquid crystal filter 12 is in the OFF state, the liquid crystal filter 12 blocks the first polarized light.

In the configuration of the light irradiating unit 10C, the output light from the light source 11 is separated into the second polarized light and the first polarized light by the polarized light separating element 13. [ Specifically, the second polarized light passes through the polarization splitting element 13, and the first polarized light is reflected to the first mirror 15A side.

The second polarized light transmitted through the polarized light separating element (13) enters the linear polarizing film (16). Since the direction of the polarization axis PA3 of the linear polarizing film 16 is the same as the polarizing direction of the second polarized light, the second polarized light from the polarized light separating element 13 passes through the linear polarizing film 16, And enters the optical path combining section 14.

On the other hand, the first polarized light reflected by the polarization splitting element 13 is reflected from the first mirror 15A to the second mirror 15B side. The first polarized light reflected by the first mirror 15A is incident on the liquid crystal filter 12 because the liquid crystal filter 12 is disposed between the first mirror 15A and the second mirror 15B.

When the liquid crystal filter 12 is in the ON state, the first polarized light passes through the liquid crystal filter 12. The first polarized light transmitted through the liquid crystal filter 12 is reflected by the second mirror 15B and enters the optical path combining section 14. [

The optical path synthesizing section 14 outputs the second polarized light having passed through the linear polarizing film 16 and the optical path of the first polarized light from the second mirror 15B in a coincident manner. In other words, the optical path combining section 14 combines the second polarized light and the first polarized light, and outputs the combined light as unpolarized light. Therefore, when the liquid crystal filter 12 is in the ON state, the light irradiation unit 10C outputs the inspection light L of unpolarized light.

When the liquid crystal filter 12 is in the OFF state, the first polarized light is blocked by the liquid crystal filter 12, so that the first polarized light does not reach the optical path combining section 14. Therefore, only the second polarized light having passed through the linear polarizing film 16 is output from the optical path synthesizing section 14. That is, when the liquid crystal filter 12 is in the OFF state, the light irradiation unit 10C outputs the inspection light L which is the second polarized light.

As described above, the light irradiation unit 10C can switch between the non-polarized inspection light L and the second polarized light inspection light L by switching the liquid crystal filter 12 ON / OFF.

The light irradiating unit 10C can switch the polarized state of the inspection light L and output it by the ON / OFF control of the liquid crystal filter 12. Therefore, The defect inspection method is the same as that of the defect inspection apparatus 3A.

When the inspection light L is in the unpolarized state, the inspection light L includes the first polarized light. Therefore, in the sixth embodiment, when the liquid crystal filter 12 is in the ON state, the optical film 100 is irradiated with the inspection light L which is parallel Nicol light. On the other hand, when the liquid crystal filter 12 is in the OFF state and the inspection light L is the second polarized light, the optical film 100 is irradiated with the inspection light L which is Cross-Nicol light. Therefore, in the defect inspection apparatus 3F, the positive transmission inspection optical system and the cross-Nicoll transmission inspection optical system are integrated, and these inspection optical systems are switched by the ON / OFF control of the liquid crystal filter 12. [ Therefore, the defect inspection method of the optical film using the defect inspection apparatus 3F and the defect inspection apparatus 3F has the same operational effects as those of the first embodiment.

When light passes through the liquid crystal filter 12, the light amount is attenuated more than, for example, when the light passes through the polarizing film. However, when the defect inspection is performed using the defect inspection apparatus 3F as a cross-Nicol penetration inspection optical system, since the second polarized light does not pass through the liquid crystal filter 12, in inspection of the cross- , It is easy to secure the amount of light necessary for illumination of the optical film 100. When defect inspection is performed using the defect inspection apparatus 3F as a positive transmission inspection optical system, the first polarized light passes through the liquid crystal filter 12. In this case, as described above, attenuation of light quantity occurs. However, in positive transmission, the amount of light necessary for illumination of the optical film 100 is easier to secure than cross-Nicol transmission. Therefore, the influence of attenuation of the light amount is small. Depending on the configuration of the liquid crystal filter 12, the amount of light passing through the linear polarizing film 12a can be adjusted by adjusting the voltage applied to the liquid crystal filter 12. [ As a result, in the defect inspection apparatus 3F using the liquid crystal filter 12, the amount of increase in the amount of light from the light source 11 can be reduced to obtain the amount of light required for defect inspection, It contributes to energy saving by widening.

The defect inspection apparatus 3F can be applied to the defect inspection system 1 shown in Fig. 1 instead of the defect inspection apparatus 3A. Therefore, the manufacturing method of the optical film 100 including the defect inspection method using the defect inspection apparatus 3F has the same operational effects as those of the first embodiment.

In the sixth embodiment, the light irradiation unit 10C includes the light source 11, the polarization separation element 13, the optical path composition unit 14, the first mirror 15A, the second mirror 15B, The linear polarizing film 16, and the liquid crystal filter 12 have been described. However, the light irradiation unit 10C includes the light source 11, the polarization separation element 13, the optical path composition unit 14, the first mirror 15A, the second mirror 15B, the liquid crystal filter 12 ). That is, the light irradiating unit 10C may not have the linear polarizing film 16. In the embodiment in which the light irradiating section 10C has the linear polarizing film 16, the accuracy of the polarizing direction of light passing through the linear polarizing film 16 is improved. Therefore, the inspection can be performed in a more accurate cross-Nicol state.

(Seventh Embodiment)

10 is a schematic diagram of a defect inspection apparatus 3G according to the seventh embodiment. The defect inspection apparatus 3G is different from the defect inspection apparatus 3G in that the light irradiation section 10C is arranged on the same side as the image pickup section 20A as viewed from the optical film 100 so as to constitute a reflection inspection optical system together with the image pickup section 20A , Which is different from the sixth embodiment. The operation and effects of the defect inspection method using the defect inspection apparatus 3G and the defect inspection apparatus 3G are also the same as those of the sixth embodiment, except for the difference. Also in Fig. 10, an example of an optical path of light is schematically shown by a one-dot chain line.

The configuration of the defect inspection apparatus 3G corresponds to a configuration in which the light irradiation section 10A is replaced with the light irradiation section 10C in the defect inspection apparatus 3D of the fourth embodiment. Therefore, the defect inspection method using the defect inspection apparatus 3G and the defect inspection apparatus 3G has the same operational effects as those of the reflection inspection optical system described in the fourth embodiment.

In the seventh embodiment, similarly to the case of the sixth embodiment, the light irradiating section 10C may not have the linearly polarizing film 16. The action and effect in the case where the light irradiation part 10C has the linearly polarizing film 16 is the same as in the case of the sixth embodiment.

In order to improve the accuracy of the polarization direction of two polarized lights separated by the polarized light separating element 13 in the sixth and seventh embodiments, it is preferable that the polarized light separating element 13, the liquid crystal filter 12, A linear polarizing film in the state of the first polarized light and the parallel Nicole may be further provided between the mirror 15A and the liquid crystal filter 12. [

(Eighth embodiment)

11 is a schematic diagram of a defect inspection apparatus 3H according to the eighth embodiment. The defect inspection apparatus 3H is different from the defect inspection apparatus 3F of the sixth embodiment in that the defect inspection apparatus 3H includes the light irradiation unit 10D instead of the light irradiation unit 10C. Also in Fig. 11, an example of an optical path of light is schematically shown by a one-dot chain line.

The light irradiating unit 10D has a light source 11, an optical path combining unit 14, a linear polarizing film 16, a light source 17, and a liquid crystal filter 12A. The configurations of the light source 11, the optical path synthesizing section 14, and the linearly polarizing film 16 are the same as those of the sixth embodiment. The arrangement relationship of the light source 11, the linear polarizing film 16 and the optical path synthesizing section 14 is such that the polarization separating element 13 is not disposed between the light source 11 and the linear polarizing film 16 Otherwise, it is the same as in the case of the sixth embodiment.

The light source 17 is disposed laterally (along the Y direction) of the optical path combining section 14. A liquid crystal filter 12A is disposed between the light source 17 and the optical path synthesizing section 14. [ The liquid crystal filter 12A functions as a shutter for switching between the case of passing the first deflected light and the case of blocking the light by switching ON / OFF. The light source 17 and the liquid crystal filter 12A are arranged such that when the first polarized light output from the liquid crystal filter 12A is incident on the optical path combining section 14, And the second optical path of the second polarized light.

11, the liquid crystal filter 12A includes a liquid crystal cell 12b, a linear polarizing film 12a provided on one surface of the liquid crystal cell 12b, and a liquid crystal cell 12b on the other side of the liquid crystal cell 12b (The surface opposite to the surface on which the linear polarizing film 12a is provided) of the linear polarizing film 12c. The polarization axis PA2 of the linearly polarizing film 12a and the polarization axis PA5 of the linearly polarizing film 12c are orthogonal to each other. The liquid crystal filter 12A is arranged such that the linear polarizing film 12c faces the light source 17 and the polarization axis PA2 is parallel to the polarization axis PA1. In the configuration and arrangement of the liquid crystal filter 12A, the liquid crystal filter 12A is in the OFF state, and the first polarized light among the light (non-polarized light) from the light source 17 selectively passes through the liquid crystal filter 12A , And the liquid crystal filter 12A is in the ON state, the light from the light source 17 is cut off.

The light irradiation unit 10D has the same function as the light irradiation unit 10C by controlling ON / OFF of the liquid crystal filter 12A while outputting light from the light source 11 and the light source 17, respectively. Therefore, the defect inspection method of the optical film 100 using the defect inspection apparatus 3H and the defect inspection apparatus 3H has the same operational effects as those of the sixth embodiment.

In the defect inspection apparatus 3H, the cross-Nicol penetration inspection optical system can also be realized by turning off the light source 17, that is, by stopping the output of the light from the light source 17. [

The defect inspection apparatus 3H employs a transmission inspection optical system. However, as in the seventh embodiment, the light irradiation unit 10D may be disposed on the same side as the image pickup unit 20A, and a reflection inspection optical system may be employed.

(Ninth embodiment)

In the first to eighth embodiments, a defect inspection apparatus having an optical film having a linear polarization characteristic as an inspection target has been described. However, the optical film may not have a linear polarization characteristic. As a ninth embodiment, a defect inspection apparatus in the case where an optical film having no linearly polarized light characteristic is to be inspected will be described. 12 is a schematic diagram of a defect inspection apparatus 3I according to the ninth embodiment.

The defect inspection device 3I is a device for inspecting defects of the optical film 100A that do not have a linear polarization characteristic. Examples of the optical film 100A include a protective film 102 and a protective film 103 shown in Fig. 2, a retardation film, and the like.

The defect inspection apparatus 3I is different from the defect inspection apparatus 3A of the first embodiment in that it has a linearly polarizing film (first linearly polarizing film) The defect inspection apparatus 3I will be described with reference to the difference point.

The linear polarizing film 40 is a film having a linear polarization characteristic, and has a polarization axis PA4. The linearly polarizing film 40 is disposed between the optical film 100A and the imaging section 20A so as to form a crossed Nicol with the linearly polarizing film 12a of the liquid crystal filter 12. [ In Fig. 12, the linearly polarizing film 40 is arranged such that the Y direction coincides with the direction of the polarization axis PA4.

A method of inspecting defects of the optical film 100A using the defect inspection apparatus 3I will be described. When defect inspection is performed, inspection light L of a predetermined polarization state is irradiated from the light irradiation unit 10A to the inspection area of the optical film 100A (inspection light irradiation step). When the inspection light L is irradiated to the optical film 100A in the inspection light irradiation process, the inspection area is imaged by the imaging unit 20A (more specifically, the camera 21) (imaging process).

In the inspection light irradiation step, the predetermined polarization state of the inspection light L is switched by ON / OFF controlling the liquid crystal filter 12 as in the case of the first embodiment. In the imaging step, the inspection area of the optical film 100A is picked up by the imaging unit 20A in synchronization with the switching of the predetermined polarization state of the inspection light L.

Since the optical film 100A does not have a linear polarization characteristic, both the first polarized light and the second polarized light transmit the optical film 100A. A linear polarizing film 40 is disposed between the optical film 100A and the imaging section 20A and the first polarized light passes through the linear polarizing film 40 and the second polarized light passes through the linear polarizing film 40, .

Therefore, also in the defect inspection apparatus 3I, the positive transmission inspection optical system and the cross-Nicoll transmission inspection optical system are integrated, and switching of these inspection optical systems is performed by ON / OFF control of the liquid crystal filter 12. [ Therefore, the defect inspection method using the defect inspection apparatus 3I and the defect inspection apparatus 3I has the same operational effects as those of the first embodiment.

1, the defect inspection apparatus 3I may be replaced with the defect inspection apparatus 3A of the defect inspection system 1 of Fig. 1 in the case where the inspection target to be inspected is the optical film 100A to be transported in the carry section 2 in Fig. . The manufacturing method of the optical film including the defect inspection method using the defect inspection device 3I and the defect inspection device 3I has the same operational effect as that of the first embodiment.

The defect inspection method of the optical film 100A using the defect inspection device 3I and the defect inspection device 3I may be applied to the case where the optical film 100A itself is manufactured, It may be used for defect inspection of the protective film 102 and the protective film 103 being transported until they are bonded to the film body 101 in the manufacturing process.

The defect inspection apparatus 3I has been described as a modification of the defect inspection apparatus 3A. However, also in the configuration of the defect inspection apparatus described as the second embodiment and the fourth to eighth embodiments, as described in the ninth embodiment, the linear polarizing film 40 is further provided, It is possible to perform defect inspection of the film 100A. Specifically, as described in the fourth to seventh embodiments, when the light irradiating unit has the liquid crystal filter 12, a linear polarizing film 40 (see FIG. 4) is provided between the optical film 100A having no linearly polarizing characteristic and the image sensing unit As described in the ninth embodiment may be arranged so as to form crossed-Nicole with the linear polarizing film 12a of the liquid crystal filter 12. [ As described in the eighth embodiment, when the light irradiating unit is provided with the linear polarizing film 16 and the liquid crystal filter 12A, the linear polarizing film 16A and the liquid crystal filter 12A are disposed between the optical film 100A, (40) may be arranged so as to form crossed Nicol with the linear polarizing film (16). When the defect inspection apparatuses according to the sixth to eighth embodiments are provided with the linearly polarizing film 40 for defect inspection of the optical film 100A, And the linear polarizing film 16 corresponds to the second linear polarizing film.

As described in the second embodiment, when the image pickup section has the liquid crystal filter 12, the linear polarizing film 40 is disposed between the optical film and the light irradiating section, and the liquid crystal filter 12 ) And the cross polarizing film 12a.

As described in the third embodiment, when the light irradiation unit and the image pickup unit have a liquid crystal filter, the defect inspection of the optical film 100A can be performed by a combination of ON / OFF control of the liquid crystal filter of each of the light irradiation unit and the image pickup unit Do.

An optical film is exemplified as a film having no polarization property, but an example of a film having no polarization property may be a separator film for a battery or the like.

Various embodiments of the present invention have been described above. However, the present invention is not limited to the above-described various embodiments, and various modifications are possible without departing from the gist of the present invention.

In the illustrated various embodiments, one control device controls the liquid crystal filter and the camera, but a separate control device may be provided for the liquid crystal filter and the camera. In the above-described various embodiments, the defect inspection apparatus has a control device. However, the control apparatus may be a separate component from the defect inspection apparatus. For example, it may be a component of the defect inspection system, or may be a device which the user of the defect inspection apparatus appropriately prepares.

The filter unit is not limited to the liquid crystal filter as long as the polarization direction of the light to be passed can be switched.

A case where a film and a liquid crystal filter are arranged such that a predetermined polarizing direction of light passing through the filter section and a polarization axis of the film are in a parallel Nicoll state or a Cross Nicol state when the object to be inspected is a film having a linear polarization characteristic Respectively. However, depending on the object to be inspected, the filter portion and the film may be arranged so that the predetermined polarization direction of the light passing through the filter portion and the polarization axis of the film are in the half crossed Nicols state. Alternatively, when the filter unit is a liquid crystal filter, the voltage applied to the liquid crystal filter may be adjusted so that the predetermined polarization direction of the light passing through the filter unit and the polarization axis of the film are in the half crossed Nicols state. In the case where the object to be inspected is a film having no linear polarization property, the arrangement relationship of the linear polarizing films paired with the filter section may be half-crossed Nicol as described above. In the case where the object to be inspected is a film having no linear polarization characteristic and the filter is a liquid crystal filter, the relationship between the predetermined polarization direction of the light passing through the filter portion and the polarization axis of the linear polarizing film paired with the filter portion, The voltage applied to the liquid crystal filter may be adjusted so as to be in the Nicole state.

The various embodiments exemplified so far may be appropriately combined with each other. For example, the light irradiation unit described in one embodiment may be replaced with the light irradiation unit of another embodiment, or the imaging unit described in one embodiment may be replaced with the imaging unit of another embodiment.

3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I ... Defect inspection apparatuses 10A, 10A1, 10A2, 10B, 10C, 10D ... Light irradiation part, 11 ... Light source, 12 ... Liquid crystal filter, 13 ... Polarized light separation element, 14 ... Optical path synthesis section, 15A ... The first mirror (optical system), 15B ... The second mirror (optical system), 16 ... Linear polarizing film, 20A, 20B ... An image pickup section, 21 ... Camera, 40 ... Linear polarizing film (first linear polarizing film), 100, 100A ... Optical film (film), A ... Inspection area, L ... Inspection light.

Claims (17)

1. A film defect inspection apparatus comprising:
A light irradiation unit for outputting inspection light to be irradiated onto an inspection area of the film;
An image pickup section
And,
At least one of the light irradiation unit and the imaging unit has a filter unit for selectively passing light in a predetermined polarization direction,
Wherein the filter unit is configured to adjust the predetermined polarization direction. The method according to claim 1,
Wherein the filter unit has a liquid crystal filter having a linear polarizing film provided on one surface of a liquid crystal cell. 3. The method according to claim 1 or 2,
The film is an optical film having a linear polarization characteristic,
The light-
A light source,
And the filter portion disposed between the light source and the film. 3. The method according to claim 1 or 2,
The film is an optical film having a linear polarization characteristic,
The light-
A light source,
A polarized light separating element for separating the light from the light source into first polarized light and second polarized light whose polarization directions are orthogonal to each other,
An optical path synthesizing unit arranged on the optical path of the second polarized light separated by the polarized light separating element and composing the optical path of the first polarized light separated by the polarized light separating element to the optical path of the second polarized light;
An optical system for guiding the first polarized light separated by the polarized light separating element to the optical path combining section,
And the filter portion disposed on the optical path of the first polarized light guided by the optical system,
The film is disposed on the optical path of the second polarized light,
Wherein the filter unit is switched when selectively passing the first polarized light and when selectively passing the second polarized light. 5. The method of claim 4,
Wherein the light irradiating portion is disposed between the polarized light separating element and the optical path combining portion on the optical path of the second polarized light and is disposed in a crossed Nicols state with respect to the film, A defect inspection apparatus. 6. The method according to any one of claims 1 to 5,
The film is an optical film having a linear polarization characteristic,
Wherein,
Camera,
And the filter portion
And a defect inspection apparatus. 3. The method according to claim 1 or 2,
Further comprising a first linear polarizing film disposed between the film and the imaging unit,
The film is a film having no linear polarization property,
The light-
A light source,
Wherein the filter portion
And a defect inspection apparatus. 3. The method according to claim 1 or 2,
Further comprising a first linear polarizing film disposed between the imaging section and the film,
The film is a film having no polarization property,
The light-
A light source,
A polarized light separating element for separating the light from the light source into first polarized light and second polarized light whose polarization directions are orthogonal to each other,
An optical path synthesizing unit arranged on the optical path of the second polarized light and combining the optical path of the first polarized light with the optical path of the second polarized light;
An optical system for guiding the first polarized light separated by the polarized light separating element to the optical path combining section,
And a second straight line passing through the first linearly polarizing film and passing through the second linearly polarizing film, the second linearly polarizing film being disposed between the polarized light separating element and the optical path synthesizing section on the optical path of the second polarized light, A polarizing film,
Wherein the filter unit is disposed on an optical path of the first polarized light guided by the optical system,
Lt; / RTI &
The film is disposed on the optical path of the second polarized light,
Wherein the filter unit is switched when selectively passing the first polarized light and when selectively passing the second polarized light. 3. The method according to claim 1 or 2,
A first linearly polarizing film disposed between the light irradiating section and the film,
The film is a film having no polarization property,
Wherein,
Camera,
And the filter portion
And a defect inspection apparatus. 10. The method according to any one of claims 1 to 9,
Two light irradiation portions are provided,
The first light irradiation part being one of the two light irradiation parts is disposed on the side opposite to the imaging part as viewed from the film,
And the second light irradiation part which is the other of the two light irradiation parts is arranged on the same side of the film as the imaging part. A defect inspection method for a film,
An inspection light irradiation step of irradiating the inspection area of the film with inspection light by a light irradiation part,
An image pickup step of picking up the inspection area by the image pickup section
And,
At least one of the light irradiation unit and the imaging unit has a filter unit for selectively passing light in a predetermined polarization direction,
Wherein the filter unit is configured to adjust the predetermined polarization direction. 12. The method of claim 11,
Wherein the filter unit has a liquid crystal filter having a linear polarizing film provided on one surface of a liquid crystal cell. 13. The method according to claim 11 or 12,
The film is an optical film having a linear polarization characteristic,
Wherein the light irradiating unit outputs the inspection light in the predetermined polarization direction by passing light from the light source through the filter unit,
And in the inspection light irradiation step, the predetermined polarizing direction of the inspection light is adjusted by the filter unit. 14. The method according to any one of claims 11 to 13,
The film is an optical film having a linear polarization characteristic,
Wherein the image pickup section picks up the inspection area of the film with a camera through the filter section,
And in the imaging step, the predetermined polarization direction through which the filter section passes is adjusted. 13. The method according to claim 11 or 12,
The film is a film having no polarization property,
Wherein the light irradiating unit outputs the inspection light in the predetermined polarization direction by passing light from the light source through the filter unit,
In the inspection light irradiation step, the predetermined polarizing direction of the inspection light is switched by the filter unit,
And in the imaging step, the imaging section captures the inspection area through the first linearly polarizing film disposed between the film and the imaging section. 13. The method according to claim 11 or 12,
The film is a film having no polarization property,
Wherein the light irradiating unit outputs the inspection light in the predetermined polarization direction by passing light from the light source through the filter unit,
Wherein the image pickup section picks up the inspection area of the film with a camera through the filter section,
In the inspection light irradiation step, the inspection light is irradiated to the film through the first linearly polarizing film disposed between the light irradiation part and the film,
And in the imaging step, the predetermined polarization direction through which the filter section passes is adjusted. A method for producing a film, comprising the defect inspection method according to any one of claims 11 to 16.

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