JP2019070617A - Defect inspection device, defect inspection method, and film manufacturing method - Google Patents

Abstract

To provide a defect inspection device having different inspection optical system integrated, a defect inspection method, and a film manufacturing method.SOLUTION: A defect inspection device 3A according to an embodiment is a defect inspection device of a film 100 which comprises: a light irradiation part 10A for outputting inspection light L irradiating inspection region A of the film therewith; and an imaging part 20A for picking up an image of an inspection region. At least one of the light irradiation part and the imaging part has a filter part 12 which selectively allows light in a predetermined polarization direction to pass therethrough. The filter part is configured to be adjusted in a predetermined polarization direction.SELECTED DRAWING: Figure 2

Description

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

  There are known defect inspection devices that detect defects in optical films such as polarizing films and retardation films, films used in battery separators, and the like. In this type of defect inspection apparatus, the film is transported by the transport unit, light is irradiated to the inspection region of the film by the light irradiation unit, the inspection region of the film is imaged by the imaging unit, and defect inspection is performed based on the captured image. Do. As a defect inspection apparatus, for example, an apparatus using an inspection optical system based on the regular transmission method (see Patent Document 1) and an apparatus using an inspection optical system based on the Cross Nicol transmission method (see Patent Document 2) are known. It is done.

JP, 2012-167975, A JP 2007-212442 A

  In defect inspection, in order to detect defects more reliably, it is desirable to detect defects with a plurality of different inspection optical systems (for example, a regular transmission inspection optical system and a cross nicol inspection optical system). However, separately preparing these inspection optical systems increases the introduction cost and the management cost, and therefore, integration of a plurality of inspection optical systems is desired.

  Then, this invention aims at providing the defect inspection apparatus which integrated different inspection optical systems, the defect inspection method, and the manufacturing method of a film.

  The defect inspection apparatus according to one aspect of the present invention is a film defect inspection apparatus, and includes a light irradiation unit that outputs inspection light to be irradiated to the inspection region of the film, and an imaging unit that images the inspection region. At least one of the light irradiation unit and the imaging unit has a filter unit that selectively transmits light in a predetermined polarization direction, and the filter unit is configured to be able to adjust the predetermined polarization direction. .

  The defect inspection method according to another aspect of the present invention is a film defect inspection method, wherein an inspection light irradiation step of irradiating inspection light to the inspection region of the film by the light irradiation unit; and imaging the inspection region by the imaging unit An imaging process, 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, and the filter unit is configured to select the predetermined polarization direction. It is configured to be adjustable.

  In the defect inspection apparatus and the defect inspection method, the inspection area is imaged by the imaging unit in a state in which the inspection light is irradiated to the inspection area of the film by the light irradiation unit. Therefore, the inspection image of the inspection area illuminated by the inspection light from the light emitting unit can be acquired by the imaging unit. At least one of the light emitting unit and the imaging unit has a filter unit that selectively transmits light in a predetermined polarization direction, and the filter unit is configured to be capable of adjusting the predetermined polarization direction. Therefore, it is possible to obtain inspection images of different inspection states by adjusting the predetermined polarization direction by the filter unit. That is, different inspection optical systems can be integrated in one defect inspection apparatus, and defect inspection can be performed in each of the different inspection optical systems by selectively adjusting the polarization direction of light that the filter unit passes. .

  The filter section 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 side of a liquid crystal cell. In this case, the polarization direction of the light passing through the liquid crystal filter can be adjusted in a short time (for example, 0.1 msec to 25 msec) depending on the presence or absence of the application of the voltage to the liquid crystal filter.

  The film in the defect inspection apparatus according to one embodiment is an optical film having linear polarization characteristics, and the light irradiation unit has a light source, and the filter unit disposed between the light source and the film. You may In the defect inspection method according to one embodiment, the film is an optical film having linear polarization characteristics, and the light irradiation unit transmits inspection light of the predetermined polarization direction by passing light from a light source through the filter unit. In the inspection light irradiation step, the predetermined polarization direction of the inspection light may be adjusted by the filter unit.

  In this case, since the predetermined polarization direction of the inspection light is adjusted, the 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 this specification, the parallel Nicol state means that two polarization directions (or polarization directions and polarization axes) are substantially parallel, in other words, an angle between two polarization directions (or polarization directions and polarization axes) is 0. A state of at least 1 ° and at most 1 °, preferably at 0 °, means that the crossed Nicol state is such that the angle between two polarization directions (or polarization direction and polarization axis) is substantially orthogonal, In other words, it means a state of 85 ° or more and 105 ° or less, preferably 90 °, and the half cross Nicol state is an angle formed by two polarization directions (or polarization direction and polarization axis). Means that is greater than 1 ° and less than 85 °.

  In the defect inspection apparatus according to one embodiment, the film is an optical film having linear polarization characteristics, and the light irradiation unit includes a light source, and light from the light source with first polarized light whose polarization directions are orthogonal to each other. A polarization separation element for separating into second polarization light, and an optical path of the first polarization light separated by the polarization separation element, disposed on the optical path of the second polarization light separated by the polarization separation element An optical path combining unit for combining the first polarized light into the optical path of the second polarized light, an optical system for guiding the one polarized light separated by the polarization separation element to the optical path combining unit, and the first polarized light guided by the optical system And the film is disposed on the optical path of the second polarized light, and the filter selectively passes the first polarized light. And selectively passing the second polarized light It may be switched to the door.

  In this configuration, the optical film has a linear polarization characteristic that transmits the first polarized light. When the filter unit selectively passes the first polarized light, the output light from the light source is separated into the first polarized light and the second polarized light by the polarization separation element, and then the separated first polarized light and the second polarized light are separated. The light paths of the light are synthesized by the light path synthesis unit and output toward the film to be inspected. Therefore, when the filter unit passes the first polarized light, 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 an optical film having linear polarization characteristics in a 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 separation element, the separated first polarized light is filtered by the filter unit. It is cut off. Therefore, only the second polarized light is output from the optical path combining unit. Therefore, when the filter unit selectively passes the second polarized light, the light irradiation unit outputs the inspection light as the second polarized light. Therefore, defect inspection in the cross nicol state is possible for the optical film having linear polarization characteristics.

  The light emitting unit is disposed between the polarization separation element and the optical path combining unit on the light path of the second polarized light, and is disposed in a cross nicol state with respect to the film, and the second polarized light It may have a polarizing film that transmits light.

  The film in the defect inspection apparatus according to one embodiment is an optical film having linear polarization characteristics, and the imaging unit has a camera, and the filter unit disposed between the camera and the film. You may In the defect inspection method according to one embodiment, the film is an optical film having linear polarization characteristics, the imaging unit images the inspection region of the film with a camera through the filter unit, and the imaging step includes The predetermined polarization direction through which the filter unit passes may be adjusted.

  In this case, by switching the polarization direction of the light passing through the filter unit, the positional relationship between the optical film having linear polarization characteristics and the filter unit may be, for example, between the parallel Nicol state and the cross Nicol state or half cross Nicol state. It is switchable with. Thus, for example, defect inspection of an optical film having linear polarization characteristics can be performed in, for example, a parallel nicol state, and also in a cross nicol state or a half cross nicol state.

  The defect inspection apparatus according to an embodiment further includes a first linear polarizing film disposed between the film and the imaging unit, wherein the film is a film having no linear polarization characteristic, and the light is The irradiation unit may have a light source and the filter unit disposed between the light source and the film. In the defect inspection method according to one embodiment, the film is a film having no polarization characteristic, and the light irradiation unit transmits the light from a light source to the filter unit and thereby the inspection light of the predetermined polarization direction. And the filter unit switches the predetermined polarization direction of the inspection light in the inspection light irradiation process, and the imaging unit is disposed between the film and the imaging unit in the imaging process. The inspection area may be imaged through the first linearly polarizing film.

  In this case, by switching the polarization direction of the light passing through the filter portion, it is possible to form a parallel Nicol state by the first linearly polarizing film and the filter portion and to form a cross nicol state or a half cross nicol state. Therefore, even when the film does not have linear polarization characteristics, for example, defect inspection in the parallel Nicol state and defect inspection in the cross Nicol state or half cross Nicol state can be performed.

  The defect inspection apparatus according to an embodiment further includes a first linear polarizing film disposed between the imaging unit and the film, and the film is a film having no polarization characteristic, and the light irradiation. A light source, a polarization separation element for separating light from the light source into first polarized light and second polarized light whose polarization directions are orthogonal to each other, and an optical path of the second polarized light, An optical path combining unit that combines the optical path of the first polarized light into the optical path of the second polarized light; an optical system that guides the first polarized light separated by the polarization separation element to the optical path combining unit; A second light source is disposed between the polarization separation element and the optical path combining unit on the optical path of the polarized light, and is disposed in a cross nicol state with respect to the first linearly polarizing film and transmits the second polarized light. Linear polarizing film and the above optical system The filter section disposed on the optical path of the first polarized light to be guided, the film is disposed on the optical path of the second polarized light, and the filter section is the first polarized light May be switched between selectively passing through and selectively passing through the second polarized light.

  Also in this case, by switching the polarization direction of the light passing through the filter portion, it is possible to form a parallel Nicol state by the first linearly polarizing film and the filter portion and to form a cross Nicol state. Therefore, even if the film does not have linear polarization characteristics, for example, defect inspection in the parallel nicol state and defect inspection in the cross nicol state can be performed.

  The defect inspection device according to one embodiment further includes a first linear polarization film disposed between the light irradiation unit and the film, and the film is a film having no polarization characteristic, and the imaging The unit may have a camera and the filter unit disposed between the camera and the film. In the defect inspection method according to one embodiment, the film is a film having no polarization characteristic, and the light irradiation unit transmits the light from a light source to the filter unit and thereby the inspection light of the predetermined polarization direction. And the imaging unit captures an image of the inspection area of the film with the camera through the filter unit, and the inspection light irradiation step arranges the inspection light between the light irradiation unit and the film. The optical film may be irradiated via the first linearly polarizing film, and the predetermined polarization direction through which the filter section passes may be adjusted in the imaging step.

  In this case, by switching the polarization direction of the light passing through the filter portion, it is possible to form a parallel Nicol state by the first linearly polarizing film and the filter portion and to form a cross nicol state or a half cross nicol state. Therefore, even when the film does not have linear polarization characteristics, for example, defect inspection in the parallel Nicol state and defect inspection in the cross Nicol state or half cross Nicol state can be performed.

  The defect inspection apparatus according to one embodiment includes two of the light irradiation units, and the first light irradiation unit, which is one of the two light irradiation units, is opposite to the imaging unit as viewed from the film. The second light irradiation unit, which is disposed on the side and is the other of the two light irradiation units, may be disposed on the same side as the imaging unit with respect to 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 also relates to a method for producing a film comprising the step of inspecting the film by the defect inspection method according to the other aspect of the present invention.

  According to the present invention, the present invention can provide a defect inspection apparatus in which different inspection optical systems are integrated, a defect inspection method, and a method of manufacturing a film.

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

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same symbols are given to the same elements, and duplicate explanations are omitted. The dimensional proportions in the drawings do not necessarily coincide with those in the description.

First Embodiment
FIG. 1 is a schematic view of a defect inspection system including the defect inspection apparatus according to the first embodiment. The defect inspection system 1 includes the conveyance unit 2 and the defect inspection apparatus 3A, and the defect inspection apparatus 3A disposed in the conveyance path while conveying the strip-like optical film 100 in the longitudinal direction by the conveyance unit 2 , And defect inspection of the optical film 100.

  The transport unit 2 has a transport roller R. The transport unit 2 may include a tension application device for applying tension to the optical film 100 to be transported, in addition to the transport roller R. FIG. 1 shows XYZ orthogonal coordinates used for the convenience of description. The X direction indicates the width direction of the optical film 100, and the Y direction indicates 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. Also in the description of the other drawings, description may be made using similar XYZ orthogonal coordinates.

  The defect inspection system 1 may include a marking device 4 as shown in FIG. The marking device 4 is a device that applies a mark M on the optical film 100 using defect information sent from the defect inspection device 3A. The marking device 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. As the marker head moves on the arm in the width direction X, a mark M is placed on the optical film 100. The marking device 4 may be configured to be controlled by the defect inspection device 3A, or the marking device 4 itself may have a control unit such as a computer. In addition, the marking device 4 may two-dimensionally code the defect information sent from the defect inspection device 3A and print it on the optical film 100.

  The defect inspection performed by the defect inspection apparatus 3A is a defect map indicating the position of the inspected defect in the optical film 100, in addition to the process of detecting a defect that may occur during the manufacturing process (including the conveying process) of the optical film 100. May include the process of creating The defects include, for example, air bubbles, foreign particles and bright spots mixed in the optical film 100 in the manufacturing process of the optical film 100, foreign particles attached to the optical film 100, and irregularities formed on the optical film 100.

  The defect inspection apparatus 3A according to the first embodiment will be described using FIG. FIG. 2 is a schematic view of the defect inspection apparatus 3A according to the first embodiment, and (a) of FIG. 2 shows the case where the liquid crystal filter (filter part) of the defect inspection apparatus 3A is in the OFF state. Part (b) of FIG. 2 shows the liquid crystal filter (filter part) of the defect inspection apparatus 3A in the ON state.

  In FIG. 2, as an optical film 100 inspected by the defect inspection apparatus 3A, a polarizing film having a linear polarization characteristic is illustrated. Below, unless it refuses, the optical film 100 as a polarizing film is a laminated body of the film main body 101, the protective film 102, and the protective film 103. FIG.

  The film body 101 has linear polarization characteristics. In the first embodiment, the polarization axis PA <b> 1 of the film main body 101 is parallel to the Y direction which is the transport direction of the optical film 100. Examples of the material of the film main body 101 include PVA (polyvinyl alcohol). The protective films 102 and 103 are bonded to both sides of the film body 101. Examples of the material of the protective films 102 and 103 include TAC (Triacetyl cellulose).

  The optical film 100 may further have a film such as a protect film or a separate film on the surface opposite to the surface in contact with the film body 101 of each of the protective films 102 and 103. A film such as a protect film or a separate film can be bonded to the protective films 102 and 103 via, for example, an adhesive or an adhesive. One of the protective films 102 and 103 may be replaced by a film such as a separate film. An example of the material of the separate film and the protect film is PET (polyethylene terephtalate). The protect film and the separate film are peeled from the optical film 100 before and after the optical film 100 is bonded to, for example, a liquid crystal panel or another optical film.

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

  The defect inspection apparatus 3A includes a light irradiation unit 10A and an imaging unit 20A. The defect inspection apparatus 3A may include a control device 30 that controls the light irradiation unit 10A and the imaging unit 20A. In the following, the form provided with the control device 30 will be described unless otherwise stated. The same applies to the other embodiments.

  The light irradiation unit 10A is disposed on the opposite side of the imaging unit 20A as viewed from the optical film 100. The light irradiation unit 10A outputs the inspection light L irradiated to the optical film 100 to be inspected toward the inspection area A (see FIG. 1) of the optical film 100. The light irradiator 10A includes a light source 11 and a liquid crystal filter 12, and outputs the non-polarized light output from the light source 11 as inspection light L having a predetermined polarization state by passing through the liquid crystal filter 12. In FIG. 2, the polarization direction of the first polarized light is indicated by a double arrow, 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 non-polarized light and can output light that does not affect the composition and properties of the optical film 100. Examples of the light source 11 are, for example, metal halide lamps, halogen transmission lights, and fluorescent lamps. The light source 11 may extend in the width direction of the optical film 100 as shown in FIG. Alternatively, the light irradiation unit 10A may include a plurality of light sources 11, and they may be discretely disposed along the width direction of the optical film 100.

  In the first embodiment, the liquid crystal filter 12 selectively passes light of a predetermined polarization direction among polarized light included in the output light from the light source 11. The liquid crystal filter 12 is in the ON state when a constant voltage is applied, and is in the OFF state when 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 can be switched. The liquid crystal filter 12 is electrically connected to the control device 30, and is turned on / off by the control device 30. In the following description, unless otherwise specified, the adjustment of the predetermined polarization direction of light transmitted by the liquid crystal filter 12 means switching of the polarization direction between the first polarization and the second polarization 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 linear polarization characteristics. The liquid crystal cell 12 b is configured by filling a liquid crystal material between a pair of glass plates disposed to sandwich the separator. On the inner surfaces of the pair of glass plates, alignment films in which the alignment directions are orthogonal to each other are formed.

  In the liquid crystal filter 12, the polarization axis PA2 of the linear polarization film 12a and the polarization axis PA1 of the film main body 101 are orthogonal to each other so that the linear polarization film 12a forms a cross nicol with the optical film 100, that is, when viewed from the Z direction. It is arranged to be. Therefore, the direction of the polarization axis PA2 is orthogonal to the paper surface. Therefore, in FIG. 2, the polarization axis PA2 is indicated by a black circle. The same applies to the other drawings.

  The liquid crystal filter 12 is disposed between the light source 11 and the optical film 100 so that the linearly polarizing film 12 a is located on the light source 11 side. Therefore, when non-polarized output light from the light source 11 is incident on the liquid crystal filter 12, only the second polarized light, which is light having a polarization direction along the polarization axis PA2 of the linearly polarized film 12a, It passes and is incident on 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 the polarization direction by 90 ° in the liquid crystal cell 12b, and as shown in part (a) of FIG. It is output as 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 apparently. On the other hand, when the liquid crystal filter 12 is in the ON state, a voltage is applied to the liquid crystal cell 12 b. In this case, as shown in part (b) of FIG. 2, 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 irradiation unit 10A switches the inspection light L as the first polarized light and the inspection light L as the second polarized light by turning on / off the liquid crystal filter 12 and irradiating the optical film 100 with the inspection light L. Have.

  The arrangement relationship between the liquid crystal filter 12 and the optical film 100 shown in FIG. 2 corresponds to the arrangement relationship constituting a liquid crystal panel when the optical film 100 is bonded to the liquid crystal cell 12 b of the liquid crystal filter 12.

  The imaging unit 20A includes at least one camera 21 that images the optical film 100. In FIG. 1, an example in which the imaging unit 20A includes a plurality of cameras 21 arranged along the width direction of the optical film 100 is illustrated. The camera 21 is an area sensor camera such as a CCD camera. The camera 21 may be a line sensor camera. When the camera 21 is a line sensor camera, the inspection area A of the optical film 100 can be imaged by relatively moving the camera 21 and the optical film 100. The imaging unit 20A (specifically, the camera 21) is electrically connected to the control device 30, and controls imaging timing and inputs the obtained imaging data to the control device 30.

  The control device 30 controls the light emitting unit 10A and the imaging unit 20A. In the first embodiment, the control device 30 controls the liquid crystal filter 12 and the camera 21. However, for example, the control device 30 may control the light output timing of the light source 11. Control device 30 has, for example, a computer (calculation unit). The control device 30 detects a defect portion from the imaging data input from the imaging unit 20 and performs a function of performing image processing to highlight the defect portion, and the defect position to the image of the optical film 100 It may have a function of creating a defect map shown. In the embodiment where the defect inspection system 1 includes the marking device 4 as illustrated in FIG. 1, the control device 30 is also electrically connected to the marking device 4 as shown in FIG. 1 to control the marking device 4. Then, a mark M based on the detected defect information may be applied to the optical film 100.

  Next, a method of inspecting the optical film 100 using the defect inspection apparatus 3A will be described. When a 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 process). When the inspection light L is irradiated to 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 performing ON / OFF control of the liquid crystal filter 12. Specifically, for example, first, the liquid crystal filter 12 is set to the OFF state, and the inspection light L which is the first polarized light is irradiated to 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 to the optical film 100. After the liquid crystal filter 12 is set to the ON state, it may be switched to the OFF state.

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

  In the defect inspection method, when the inspection light L which is the first polarized light is irradiated to the optical film 100 in the inspection light irradiation process, the inspection light L and the optical film 100 are in a parallel nicol state, that is, the polarization direction of the inspection light L The inspection light L is incident on the optical film 100 in a state where the direction of the polarization axis PA1 of the film main body 101 of the optical film 100 substantially matches. On the other hand, when the inspection light L which is the second polarized light is irradiated to the optical film 100 in the inspection light irradiation process, the inspection light L and the optical film 100 are in a cross nicol state, that is, the polarization direction of the inspection light L and the polarization axis PA1. The inspection light L is incident on the optical film 100 in a state in which the light beams are substantially orthogonal to each other.

  Therefore, in synchronization with the switching of the predetermined polarization direction of the light that the liquid crystal filter 12 should pass, the imaging unit 20A picks up the inspection area A, so that the inspection light L in parallel Nicol state with respect to the optical film 100 (parallel An inspection image in the case where the optical film 100 is illuminated with the inspection light L (cross Nicol light) and the inspection light L in the cross Nicol state) 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, as shown in FIG. 2, the case of manufacturing the optical film 100 which is a laminate of the protective film 102, the film main body 101 and the protective film 103 will be described as an example.

  When manufacturing the optical film 100, the protective film 102 is bonded to one side of the film body 101 while conveying the strip-shaped film body 101, the strip-shaped protective film 102 and the strip-shaped protective film 103 in the longitudinal direction, The protective film 103 is bonded on the other side (bonding step). Bonding of the film main body 101, the protective film 102, and the protective film 103 can be performed, for example using a pair of bonding roller. In the bonding step, the protective film 102 and the protective film 103 may be bonded simultaneously to the film main body 101, or after bonding one of the protective film 102 and the protective film 103 to the film main body 101, the other may be bonded. You may

  After the bonding step, the defect inspection device is conveyed while conveying the optical film 100 as a laminate of the protective film 103, the film main body 101 and the protective film 102 between the light irradiation unit 10A and the imaging unit 20A in the defect inspection device 3A. Defect inspection of the optical film 100 is performed at 3A (defect inspection step). In the defect inspection process, defect inspection of the optical film 100 is performed by the defect inspection method described above. When the defect inspection system 1 includes the marking device 4, the step (marking step) of applying the mark M to the optical film 100 by the marking device 4 may be performed according to the result of the defect inspection step.

  In the said manufacturing method, the defect inspection apparatus 3A implemented defect inspection of the optical film 100 as a laminated body of the protective film 103, the film main body 101, and the protective film 102. FIG. However, the defect inspection apparatus 3A may perform defect inspection using the film body 101 before the protective film 103 and the protective film 102 are bonded as an optical film.

  In the defect inspection method using the defect inspection apparatus 3A and the defect inspection apparatus 3A, an inspection image of the optical film 100 by irradiation in a parallel nicol state with one apparatus and cross nicol by controlling the liquid crystal filter 12 ON / OFF An inspection image of the optical film 100 by irradiation in the state can be obtained.

  Therefore, the defect inspection apparatus 3A has one transmission inspection optical system based on parallel Nicol (hereinafter referred to as “normal transmission inspection optical system”) and one transmission inspection optical system based on cross nicol (hereinafter referred to as “cross nicol transmission inspection optical system”). Have an integrated configuration. Depending on the type of defect, the defect may be detected only by either the regular transmission inspection optical system or the cross nicol transmission inspection optical system. As in the defect inspection apparatus 3A, if the regular transmission inspection optical system and the cross nicol transmission inspection optical system are integrated into one apparatus, it is easy to reliably detect a defect in the optical film 100.

  Furthermore, in the case of a defect that can be detected by any of the regular transmission inspection optical system and the cross nicol transmission inspection optical system, for example, the defect appearing by the regular transmission inspection optical system does not appear in the inspection image of the cross nicol transmission inspection optical system In this case, it can be determined that the defect has occurred above the film main body 101 (on the side of the imaging unit 20A). That is, it is also possible to identify the defect generation layer in the optical film 100. Therefore, in the method of manufacturing the optical film 100 having the defect inspection method, it is easier to manufacture the optical film 100 as a product free of defects.

  In the defect inspection apparatus 3A, the defect inspection in the regular transmission inspection optical system and the defect inspection in the cross nicol transmission inspection optical system can be switched by the ON / OFF control of the liquid crystal filter 12. Since switching of the liquid crystal filter 12 can be performed in a shorter time (for example, 0.1 msec to 25 msec), defect inspection can be efficiently performed in the two inspection optical systems. Therefore, in the method of manufacturing the optical film 100 including the defect inspection method, the optical film 100 can be efficiently produced as a product free of defects.

Second Embodiment
In the first embodiment, the light irradiation unit includes a liquid crystal filter (filter unit), and the liquid crystal filter is disposed below the optical film 100. However, in the defect inspection apparatus, as shown in FIG. 3, the imaging unit may include a liquid crystal filter.

  FIG. 3 is a schematic view of a defect inspection apparatus 3B according to the second embodiment. The defect inspection apparatus 3B includes a light irradiation unit 10B and an imaging unit 20B. In FIG. 3, an example of the light path of light is schematically shown by the arrow of a dashed dotted line.

  The light irradiation unit 10B is different from the light irradiation unit 10A of the first embodiment in that the liquid crystal filter 12 is not provided. The structure of the light source 11 which the light irradiation part 10B has is the same as that of the case of 1st Embodiment.

  The imaging unit 20B is different from the imaging unit 20A of the first embodiment in that the imaging unit 20B includes 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 of 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 imaging unit 20B is the same as that of the first embodiment. The liquid crystal filter 12 is electrically connected to the control device 30, and is turned on / off by the control device 30.

  The liquid crystal filter 12 is disposed such that the linear polarization film 12a is located on the imaging unit 20B side, and the polarization axis PA2 of the linear polarization film 12a and the polarization axis PA1 of the film main body 101 are in a crossed nicols state. In such an arrangement, light enters the liquid crystal filter 12 from the liquid crystal cell 12 b 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 linearly polarizing film 12a. However, while passing through the liquid crystal cell 12 b, the first polarized light incident on the liquid crystal filter 12 rotates the polarization direction by 90 ° 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 output from the liquid crystal filter 12 while maintaining its polarization direction.

  Next, a method of inspecting a defect of the optical film 100 using the defect inspection apparatus 3B will be described. When the defect inspection is performed, the non-polarized output light from the light irradiation unit 10B is irradiated as the inspection light L to the inspection area A of the optical film 100 (inspection light irradiation step). When the inspection light L is irradiated to 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 imaged by the camera 21 through the liquid crystal filter 12. In the imaging step, the optical film 100 is imaged by the camera 21 in synchronization with the ON / OFF control of the liquid crystal filter 12 to obtain an inspection image when the liquid crystal filter 12 is in the ON state, and the liquid crystal filter 12 is in the OFF state. Get an examination image of the case.

  The defect inspection apparatus 3B is also an apparatus in which the regular transmission inspection optical system and the cross nicol inspection optical system are integrated as in the case of the first embodiment. This point will be described. For convenience of explanation, it is first assumed that the optical film 100 is not defective.

  In the inspection light irradiation step, the inspection light L which is non-polarized light is irradiated to the optical film 100. Since the film body 101 of the optical film 100 has the polarization axis PA1, the first polarized light contained in the inspection light L is output from the optical film 100 and enters the liquid crystal filter 12.

  If the liquid crystal filter 12 is in the OFF state, as described above, the first polarized light from the optical film 100 passes through the liquid crystal filter 12 and is converted to the second polarized light in the passing process, and then the second polarized light It is output as 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 to the OFF state, the inspection optical system of the defect inspection apparatus 3B functions as a regular transmission inspection optical system.

  On the other hand, when the liquid crystal filter 12 is in the ON state, as described above, the liquid crystal filter 12 selectively passes the second polarized light, so that the first polarized light from the optical film 100 passes through the liquid crystal filter 12. do not do. In other words, the liquid crystal filter 12 in the ON state functions as a polarization filter disposed in the cross Nicol state with respect to the optical film 100. That is, when the liquid crystal filter 12 is set to the ON state, the inspection optical system of the defect inspection apparatus 3B functions as a cross transmission inspection optical system.

  Therefore, the defect inspection apparatus 3B is also an apparatus in which the regular transmission inspection optical system and the cross nicol inspection optical system are integrated.

  In the case where the defect inspection apparatus 3B functions as a regular transmission inspection optical system, if the optical film 100 includes a defect, the defect may block light or the polarization state may be disturbed at the defect portion, thereby the inspection image The defect portion appears as a dark area, for example.

  On the other hand, when the defect inspection apparatus 3B is made to function as a cross nicol inspection optical system, if there is no defect on the upper side (the imaging unit 20B side) of the film main body 101 in the optical film 100, as described above, from the optical film 100 Since the first polarized light is output, the inspection image becomes a substantially dark image. Since the polarization state of the first polarized light from the film body 101 is disturbed by the defect if a defect exists on the upper side (the imaging unit 20B side) of the film body 101 in the optical film 100, the output from the optical film 100 The light includes second polarized light. Since this second polarized light can pass through the liquid crystal filter 12 in the ON state, the light enters the camera 21. Thus, defects appear as bright spots in the inspection image.

  The defect inspection apparatus 3B is also an apparatus in which the regular transmission inspection optical system and the cross nicol inspection optical system are integrated, and the regular transmission inspection optical system and the cross nicol inspection optical system control the liquid crystal filter 12 ON / OFF. It is switched by. Therefore, the defect inspection apparatus 3B also has the same effects as the defect inspection apparatus 3A of the first embodiment.

  Furthermore, in the case of a defect that can be detected by any of the regular transmission inspection optical system and the cross nicol transmission inspection optical system, for example, the defect appearing by the regular transmission inspection optical system does not appear in the inspection image of the cross nicol transmission inspection optical system In this case, it can be determined that the defect has occurred above the film main body 101 (on the side of the imaging unit 20A). That is, also in the defect inspection apparatus 3B, identification of the defect generation layer in the optical film 100 is also possible.

  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 method of manufacturing the optical film 100 including the defect inspection method using the defect inspection apparatus 3B has the same function and effect as the first embodiment.

Third Embodiment
FIG. 4 is a schematic view 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 dashed dotted line.

  The defect inspection apparatus 3C shown in FIG. 4 is different from the defect inspection apparatus 3A of the first embodiment in that the defect inspection apparatus 3C in the first embodiment includes the imaging unit 20B described in the second embodiment instead of the imaging unit 20A. . The liquid crystal filter 12 included in the light irradiation unit 10A, the liquid crystal filter 12 included in the imaging unit 20B, and the camera 21 are electrically connected to the control device 30, as in the first and second embodiments. It is controlled.

  A method of inspecting a defect of the optical film 100 using the defect inspection apparatus 3C will be described. When the defect inspection is performed, 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 to 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 predetermined polarization state (predetermined polarization direction) of the inspection light L is switched as in the case of the first embodiment by controlling ON / OFF the liquid crystal filter 12 of the light irradiation unit 10A. . In the imaging process, the liquid crystal filter 12 included in the imaging unit 20B is controlled ON / OFF according to the ON / OFF control of the liquid crystal filter 12 included in the light irradiation unit 10A, and the liquid crystal filter included in each of the light irradiation unit 10A and the imaging unit 20B. An inspection image is obtained according to the combination of the ON state and the OFF state of T.12.

Specifically, when the liquid crystal filter 12 of the light irradiation unit 10A is set to the OFF state, the liquid crystal filter 12 of the imaging unit 20B is controlled to be ON / OFF, and the liquid crystal filter 12 of the imaging unit 20B is in the OFF state When set in the ON state, each obtains an examination image. In addition, when the liquid crystal filter 12 of the light irradiation unit 10A is set to the ON state, the liquid crystal filter 12 of the imaging unit 20B is controlled to be ON / OFF, and the liquid crystal filter 12 of the imaging unit 20B is in the OFF state and the ON state. When set, each obtains an examination image. Therefore, in the defect inspection apparatus 3C, inspection images corresponding to the cases a to d shown in Table 1 can be obtained.

  In the case a, since the inspection light L in the parallel Nicol state is irradiated to the optical film 100, 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 a regular transmission inspection optical system.

  In case b, as in case a, the first polarized light is output from the optical film 100. In case b, since the liquid crystal filter 12 of the imaging unit 20B is set to the ON state, there is no defect in the optical film 100 (more specifically, no defect exists above the film main body 101), The light does not pass through the liquid crystal filter 12 of the imaging unit 20B. Therefore, case b corresponds to a cross nicol transmission inspection optical system.

  In the case c and the case d, since the inspection light L in the cross nicol state is irradiated to the optical film 100, it corresponds to the cross nicol transmission inspection optical system.

  As described above, also in the defect inspection apparatus 3C, the regular transmission inspection optical system and the cross nicol transmission inspection optical system are integrated, and the two optical systems can be switched by 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 effects as the defect inspection apparatus 3A of 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 method of manufacturing the optical film 100 including the defect inspection method using the defect inspection apparatus 3B has the same function and effect as the first embodiment. In the defect inspection apparatus 3C, since the defect inspection of the optical film 100 can be performed in each of the four states of the case a to the case d, inspection according to the optical film 100 can be easily performed.

Fourth Embodiment
The defect inspection apparatuses 3A, 3B, and 3C described in the first to third embodiments employ the transmission inspection optical system. However, as schematically shown in FIG. 5, the defect inspection apparatus may employ a reflection inspection optical system. FIG. 5 is a schematic view of a defect inspection apparatus 3D according to the fourth embodiment. Also in FIG. 5, an example of the light path of light is schematically shown by a dashed dotted line.

  The defect inspection apparatus 3D is different from the defect inspection apparatus 3A of the first embodiment in that the light irradiation unit 10A and the imaging unit 20A are disposed on the same side with respect to the optical film 100 to be inspected. . In other words, in the defect inspection apparatus 3D, when the inspection light L from the light irradiation unit 10A is reflected by the optical film 100 in the defect inspection apparatus 3A of the first embodiment, the reflected light is transmitted to the imaging unit 20A. The light emitting unit 10A and the imaging unit 20A are disposed to be incident. The configuration of the light irradiation unit 10A and the imaging unit 20A is the same as that of the first embodiment, and the defect inspection method of the optical film 100 using the defect inspection device 3D is the same as that of the first embodiment.

  Since the defect inspection apparatus 3D adopts a reflection inspection optical system, the inspection light L (parallel Nicol light) in the parallel Nicol state with respect to the optical film 100 is controlled by ON / OFF control of the liquid crystal filter 12 A reflection inspection image when the optical film 100 is irradiated, and a reflection inspection image when the optical film 100 is irradiated with the inspection light L (cross nicol light) in a cross nicol state with respect to the optical film 100 can be obtained. Therefore, the defect inspection apparatus 3D includes 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, "cross nicol reflection inspection optical system"). Are integrated into one. Furthermore, the regular reflection inspection optical system and the cross Nicol reflection inspection optical system can be switched by controlling the liquid crystal filter 12 ON / OFF. Therefore, the defect inspection method of the optical film 100 using the defect inspection device 3D and the defect inspection device 3D has the same function and effect as the case of the first embodiment.

  The defect inspection apparatus 3D adopts the reflection inspection optical system as described above. When the inspection light L from the light irradiator 10A is the first polarized light, the inspection light L can propagate to the lower side (the protective film 103 in FIG. 5) than the film main body 101. Therefore, in the regular reflection inspection optical system, a defect included below the film main body 101 can also be detected. Conversely, when the inspection light L from the light irradiator 10A is the second polarized light, the inspection light L can not propagate below the film main body 101. Therefore, the cross Nicol reflection inspection optical system can inspect the film body 101 and the defect located above the film body 101 but can not detect the defect below the film body 101. 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 with the regular reflection inspection optical system and the inspection with the cross nicol reflection inspection optical system.

  Specifically, if a defect can be detected by inspection using each of the regular reflection inspection optical system and the cross nicol reflection inspection optical system, the defect is positioned above the film main body 101 and the film main body 101. On the contrary, if a defect is detected by the regular reflection inspection optical system and no defect is detected by the cross nicol reflection inspection optical system, the defect is located below the film main body 101. Thus, in the defect inspection apparatus 3D, the position of the defect can be identified in more detail. The experiment (verification experiment) which verified this point is explained. In the explanation of the verification experiment, the elements corresponding to the constituent elements in the above explanation are described with the same reference numerals.

[Verification experiment]
The optical film 100 used for verification experiment was a film in which the protective film 103, the film main 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. For the optical film 100 used in the verification experiment, a film in which air bubbles are mixed on the side of the protective film 102 was used.

  In the verification experiment, the defect inspection apparatus 3D having the configuration shown in FIG. 5 was used. However, a line sensor camera was adopted as the camera 21 and an inspection image of the optical film 100 was obtained by relatively moving the line sensor camera and the optical film 100.

(First inspection)
In the first inspection, the optical film 100 is set in the defect inspection device 3D so that the protective film 102 side is positioned on the light irradiation unit 10A and the imaging unit 20A side, and the liquid crystal filter 12 is set in the OFF state and the ON state. An inspection image of the optical film 100 was obtained with the regular reflection inspection optical system and the cross Nicol reflection inspection optical system. 6 shows an inspection image in the first inspection, where (a) in FIG. 6 is an inspection image in a regular reflection inspection optical system, and (b) in FIG. 6 is a cross nicol reflection inspection. It is a test | inspection image in an optical system.

(2nd inspection)
In the second inspection, the optical film 100 was set in the defect inspection device 3D in a state where the optical film 100 is turned over with respect to the case of the first inspection. That is, the optical film 100 was set to defect inspection apparatus 3D so that the protective film 102 side might be located in the opposite side to light irradiation part 10A and imaging part 20A. Then, similarly to the case of the first inspection, an inspection image of the optical film 100 was obtained by the regular reflection inspection optical system and the cross nicol reflection inspection optical system. FIG. 7 shows an inspection image in the second inspection, where (a) in FIG. 7 is an inspection image in a regular reflection inspection optical system, and (b) in FIG. 7 is a cross nicol reflection inspection It is a test | inspection image in an optical system. In parts (a) and (b) of FIG. 7, regions indicated by alternate long and short dashed lines are regions corresponding to each other.

  In the first inspection, the bubble defect could be confirmed by inspection of the regular reflection inspection optical system and inspection of the cross nicol reflection inspection optical system. In this case, as described above, the defect is estimated to be located above the film body 101. Then, in the first inspection, since the protective film 102 including the bubble defect is positioned closer to the light emitting unit 10A and the imaging unit 20A than the film main body 101, the defect position with respect to the film main body 101 matches the one that can be determined from the inspection image. Understand that

  In the second inspection, in the inspection with the regular reflection inspection optical system, the air bubble defect could be confirmed in the area surrounded by the alternate long and short dash line in FIG. 7A, while in the inspection with the cross nicol reflection inspection optical system A bubble defect could not be confirmed in a region surrounded by a dashed dotted line in part (b) of 7. In this case, as described above, it is estimated that the defect is located below the film body 101. Then, in the second inspection, since the protective film 102 including the bubble defect is located on the opposite side to the light emitting unit 10A and the imaging unit 20A with respect to the film main body 101, the defect position with respect to the film main body 101 can be determined from the inspection image It can be understood that it is consistent with the thing.

  Therefore, in the defect inspection apparatus 3D, the position of the defect can be specified more specifically by comparing the result of the defect inspection in each of the regular reflection inspection optical system and the cross nicol reflection inspection optical system.

  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 method of manufacturing the optical film 100 including the defect inspection method using the defect inspection device 3D has the same effects as those of the first embodiment.

Fifth Embodiment
FIG. 8 is a schematic view 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 a first light irradiation unit 10A1 and a second light irradiation unit 10A2 are provided. Also in FIG. 8, an example of the light path of light is schematically shown by a dashed dotted line.

  The first light irradiation unit 10A1 is disposed on the opposite side of the imaging unit 20A as viewed from the optical film 100, and obliquely enters the inspection light L on the optical film 100. The configuration of the first light irradiation unit 10A1 is the same as the configuration of the light irradiation unit 10A of the first embodiment except that the first light irradiation unit 10A1 is disposed to be obliquely incident as described above.

  The second light irradiation unit 10A2 has the same configuration and arrangement as the light irradiation unit 10A described in the fourth embodiment. That is, the second light irradiation unit 10A2 is disposed on the optical film 100 so as to constitute a reflection inspection optical system together with the imaging unit 20A. The second light irradiation unit 10A2 is a light receiving surface of the camera 21 of the imaging unit 20A, in which 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 It may be arrange | positioned so that it may inject into the same area | region, and may be arrange | positioned so that it may inject into a different area | region.

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

  Next, a defect inspection method of the optical film 100 using the defect inspection device 3E will be described. First, 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 incident on the same region of the light receiving surface of the camera 21 of the imaging unit 20A. The form will be described.

  When the defect inspection is performed, the inspection light L is irradiated from the first light irradiation unit 10A1 to the inspection area A (see FIG. 1) of the optical film 100, and the inspection light L from the second light irradiation unit 10A2 is an optical film The inspection area A of 100 is irradiated (inspection light irradiation process). When the inspection light L is irradiated to the optical film 100 in the inspection light irradiation process, the optical film 100 is imaged by the imaging unit 20A (imaging process).

  In the inspection light irradiation step, the inspection light L is irradiated to the inspection area A of the optical film 100 at different timings from the first light irradiation unit 10A1 and the second light irradiation unit 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 (the first light irradiation unit 10A1 or the second light irradiation unit 10A2) outputs the inspection light L. The predetermined polarization state of the inspection light L is switched by performing ON / OFF control of the liquid crystal filter 12 which has.

  For example, when the inspection light L is output from the first light irradiation unit 10A1, the liquid crystal filter 12 of the first light irradiation unit 10A1 is set to the OFF state, and the inspection light L as the first polarized light is irradiated to the optical film 100. Do. Subsequently, the liquid crystal filter 12 of the first light irradiation unit 10A1 is set to the ON state, and the inspection light L which is the second polarized light is irradiated to the optical film 100. When the inspection light L is output from the second light irradiation unit 10A2, as in the case of the first light irradiation unit 10A1, the liquid crystal filter 12 included in the second light irradiation unit 10A2 is ON / OFF controlled.

  In the imaging process, the inspection area A of the optical film 100 is imaged by the camera 21 of the imaging unit 20A in synchronization with the ON / OFF control of the liquid crystal filter 12 when the inspection light L is output from the first light irradiation unit 10A1. Similarly, in synchronization with the ON / OFF control of the liquid crystal filter 12 when the inspection light L is output from the second light irradiation unit 10A2, the inspection region A of the optical film 100 is imaged by the camera 21 of the imaging unit 20A.

  When 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 incident on different areas of the light receiving surface of the camera 21 that the imaging unit 20A has. The defect inspection method 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, the inspection light L may be output at the same timing from the first light irradiation unit 10A1 and the second light irradiation unit 10A2. And the liquid crystal filter 12 which each of 1st light irradiation part 10A1 and 2nd light irradiation part 10A2 has is controlled ON / OFF. The timings of the ON / OFF control of the liquid crystal filter 12 of the first light irradiation unit 10A1 and the ON / OFF control of the liquid crystal filter 12 of the second light irradiation unit 10A2 may be the same or different.

  In the imaging process, the inspection region A of the optical film 100 is imaged by the camera 21 of the imaging unit 20A in synchronization with the timing of the ON / OFF control of the liquid crystal filter 12 of each of the first light irradiation unit 10A1 and the second light irradiation unit 10A2. Do.

  In the defect inspection apparatus 3E, the first light irradiation unit 10A1 and the imaging 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 unit 10A1 has the same function and effect as the defect inspection apparatus 3A described in the first embodiment.

  In the defect inspection apparatus 3E, the second light irradiation unit 10A2 and the imaging 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, defect inspection using the second light irradiation unit 10A2 has the same function and effect as the defect inspection apparatus 3E described in the fourth embodiment.

  Furthermore, in the defect inspection apparatus 3E, the transmission inspection optical system and the reflection inspection optical system are integrated. Therefore, a defect detectable by the transmission inspection optical system and a defect detectable by the reflection inspection optical system can be detected by one 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 method of manufacturing the optical film 100 including the defect inspection method using the defect inspection apparatus 3E has the same function and effect as the first embodiment.

Sixth Embodiment
FIG. 9 is a schematic view of a defect inspection apparatus 3F according to the sixth embodiment. The defect inspection apparatus 3F is different from the defect inspection apparatus 3A of the first embodiment in that a light irradiation unit 10C is provided instead of the light irradiation unit 10A. Also in FIG. 9, the optical path of light is schematically shown by a dashed dotted line.

  The light irradiation unit 10C includes a light source 11, a polarization separation element 13, an optical path combining 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 in the first embodiment.

  The polarization separation element 13 is disposed on the optical path of the output light from the light source 11 and separates the non-polarized output light from the light source 11 into first polarized light and second polarized light whose polarization directions are orthogonal to each other. Do. Specifically, the second polarized light is transmitted, and the first polarized light is reflected. An example of the polarization separation element 13 is an element using an APF (Advanced Polarizing Film), for example, an element in which an APF is formed on one side surface of a prism, a glass plate, or the like.

  The optical path combining unit 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 combining unit 14 is an optical element that combines the optical path of the first polarized light separated by the polarization separation element 13 with the optical path of the second polarized light and outputs it. The optical path combining unit 14 outputs the first polarized light and the second polarized light to the optical film 100 side in a state where the optical paths of the first polarized light and the second polarized light are matched. An example of the optical path combining unit 14 is the same as the polarization separation 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 separation element 13 to the light path combining unit 14. Specifically, the first mirror 15A is disposed to the side of the polarization separation element 13, and reflects the first polarized light from the polarization separation element 13 to the optical film 100 side. The second mirror 15B is disposed on the optical path of the first polarized light reflected by the first mirror 15A and to the side of the optical path combining unit 14, and the first polarized light reflected by the first mirror 15A. Is reflected to the optical path combining unit 14 side.

  The linear polarizing film 16 is an optical film having linear polarization characteristics. The linear polarization film 16 is disposed on the optical path of the second polarized light between the polarization separation element 13 and the optical path combining unit 14. The linear polarizing film 16 has a polarizing axis PA1 of the film main body 101 and a polarizing axis PA3 of the linear polarizing film 16 so that the polarizing axis PA3 is in a cross nicol state with the optical film 100, that is, viewed from the Z direction. It is arranged to be orthogonal.

  The liquid crystal filter 12 is disposed on the optical path of the first polarized light between the first mirror 15A and the second mirror 15B. In the liquid crystal filter 12, the linearly polarizing film 12a is positioned on the second mirror 15B side, and the polarization axis PA2 of the linearly polarizing film 12a is arranged in a parallel Nicol state with the optical film 100. In such an arrangement, when the liquid crystal filter 12 is in the ON state, the liquid crystal filter 12 transmits the first polarized light. 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 irradiation unit 10C, the output light from the light source 11 is separated into the second polarized light and the first polarized light by the polarization separation element 13. Specifically, the second polarized light is transmitted through the polarization separation element 13, and the first polarized light is reflected to the first mirror 15A side.

  The second polarized light transmitted through the polarization separation element 13 is incident on the linear polarization film 16. Since the direction of the polarization axis PA3 of the linear polarization film 16 is the same as the polarization direction of the second polarized light, the second polarized light from the polarization separation element 13 passes through the linear polarization film 16 and passes through the optical path combining unit 14 Incident to

  On the other hand, the first polarized light reflected by the polarization separation element 13 is reflected by the first mirror 15A toward the second mirror 15B. Since the liquid crystal filter 12 is disposed between the first mirror 15A and the second mirror 15B, the first polarized light reflected by the first mirror 15A enters the liquid crystal filter 12.

  If 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 15 B and is incident on the optical path combining unit 14.

  The optical path combining unit 14 matches the optical paths of the second polarized light passing through the linear polarizing film 16 and the first polarized light from the second mirror 15B and outputs the same. In other words, the optical path combining unit 14 combines the second polarized light and the first polarized light and outputs the combined light as non-polarized light. Therefore, when the liquid crystal filter 12 is in the ON state, the light irradiation unit 10C outputs the non-polarized inspection light L.

  If the liquid crystal filter 12 is in the OFF state, the first polarized light is blocked by the liquid crystal filter 12, so the first polarized light does not reach the optical path combining unit 14. Therefore, only the second polarized light that has passed through the linear polarizing film 16 is output from the light path combining unit 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, in the light irradiation unit 10C, the non-polarized inspection light L and the inspection light L of the second polarized light can be switched and output by ON / OFF controlling the liquid crystal filter 12.

  Since the light irradiation unit 10C can switch and output the polarization state of the inspection light L by ON / OFF control of the liquid crystal filter 12, the defect inspection method of the optical film 100 using the defect inspection apparatus 3F is the case of the defect inspection apparatus 3A. Is the same as

  When the inspection light L is in the non-polarization 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 inspection film L, which is parallel Nicol light, is irradiated to the optical film 100. 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 inspection film L is irradiated with the inspection light L which is cross nicol light. Therefore, in the defect inspection apparatus 3F, the regular transmission inspection optical system and the cross nicol inspection optical system are integrated, and the inspection optical system of these is 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 effect as the case of the first embodiment.

  When light passes through the liquid crystal filter 12, for example, the amount of light attenuates more than when passing through a polarizing film. However, when the defect inspection is performed using the defect inspection apparatus 3F as the cross nicol transmission inspection optical system, the second polarized light does not pass through the liquid crystal filter 12, so in the inspection of the cross nicol transmission inspection optical system It is easy to secure the amount of light necessary for 100 illumination. When defect inspection is performed using the defect inspection apparatus 3F as a regular transmission inspection optical system, the first polarized light passes through the liquid crystal filter 12. In this case, as described above, the light amount is attenuated. However, in the case of regular transmission, it is easier to secure the amount of light necessary for the illumination of the optical film 100 than in the cross nicol transmission. Therefore, the influence of the light amount attenuation is small. Depending on the configuration of the liquid crystal filter 12, by adjusting the voltage applied to the liquid crystal filter 12, it is possible to adjust the amount of light passing through the linearly polarizing film 12a. As a result, in the defect inspection apparatus 3F using the liquid crystal filter 12, in order to obtain the light quantity required for the defect inspection, the amount of increase of the light quantity from the light source 11 can be reduced, and the range of selection of the light source 11 widens and energy saving Contributing to

  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 method of manufacturing the optical film 100 including the defect inspection method using the defect inspection apparatus 3F has the same function and effect as 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 combining unit 14, the first mirror 15A, the second mirror 15B, the linear polarization film 16, and the liquid crystal filter 12 The case has been described. However, the light irradiation unit 10C may include the light source 11, the polarization separation element 13, the optical path combining unit 14, the first mirror 15A, the second mirror 15B, and the liquid crystal filter 12. That is, the light irradiation unit 10C may not have the linearly polarizing film 16. In the embodiment in which the light irradiation unit 10 </ b> C includes the linear polarizing film 16, the accuracy of the polarization direction of the 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
FIG. 10 is a schematic view of a defect inspection apparatus 3G according to the seventh embodiment. The defect inspection apparatus 3G is arranged on the same side as the imaging unit 20A with respect to the optical film 100 so that the light irradiation unit 10C and the imaging unit 20A constitute a reflection inspection optical system. It is different. Other than this difference, the sixth embodiment is the same as the sixth embodiment, and therefore the effects and effects of the defect inspection method using the defect inspection device 3G and the defect inspection device 3G are also the same as the sixth embodiment. Also in FIG. 10, an example of the optical path of light is schematically shown by a dashed dotted line.

  The configuration of the defect inspection apparatus 3G corresponds to the configuration in which the light irradiation unit 10A is replaced with the light irradiation unit 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 also has the same effects as the effects of the reflection inspection optical system described in the fourth embodiment.

  Also in the seventh embodiment, as in the case of the sixth embodiment, the light irradiation unit 10C may not have the linearly polarizing film 16. The operation and effect in the case where the light irradiation unit 10C includes the linearly polarizing film 16 are the same as those in the sixth embodiment.

  In the sixth and seventh embodiments, in order to improve the polarization direction accuracy of the two polarized lights separated by the polarization separation element 13, the space between the polarization separation element 13 and the liquid crystal filter 12, preferably the first mirror 15 A to the liquid crystal filter 12. And a linearly polarizing film in parallel with the first polarized light.

Eighth Embodiment
FIG. 11 is a schematic view 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 a light irradiation unit 10D is provided instead of the light irradiation unit 10C. Also in FIG. 11, an example of the optical path of light is schematically shown by a dashed dotted line.

  The light irradiation unit 10D includes a light source 11, an optical path combining unit 14, a linear polarization film 16, a light source 17, and a liquid crystal filter 12A. The configurations of the light source 11, the optical path combining unit 14, and the linear polarization film 16 are the same as those in the sixth embodiment. Furthermore, the arrangement of the light source 11, the linear polarizing film 16, and the optical path combining unit 14 is the same as that of the sixth embodiment except that the polarization separation element 13 is not disposed between the light source 11 and the linear polarizing film 16. It is.

  The light source 17 is disposed to the side (side along the Y direction) of the optical path combining unit 14. A liquid crystal filter 12A is disposed between the light source 17 and the optical path combining unit 14. The liquid crystal filter 12A functions as a shutter that switches between when passing the first polarized light and when blocking the light by switching ON / OFF. In the liquid crystal filter 12A, when the first polarized light output from the liquid crystal filter 12A enters the light path combining unit 14, the light source 17 and the liquid crystal filter 12A pass through the linearly polarized film 16 and enter the light path combining unit 14 It is arranged to be combined with the optical path of the second polarized light.

  For example, as shown in FIG. 11, the liquid crystal filter 12A includes a liquid crystal cell 12b, a linear polarizing film 12a provided on one side of the liquid crystal cell 12b, and the other side of the liquid crystal cell 12b (the linear polarizing film 12a is And a linearly polarizing film 12c on the side opposite to the side to be provided. The polarization axis PA2 of the linear polarization film 12a and the polarization axis PA5 of the linear polarization film 12c are orthogonal to each other. The liquid crystal filter 12A is disposed such that the linearly polarizing film 12c faces the light source 17, and the polarization axis PA2 is in a parallel Nicol state with the polarization axis PA1. In the configuration and arrangement of the liquid crystal filter 12A, when the liquid crystal filter 12A is in the OFF state, the first polarized light of the light (non-polarized light) from the light source 17 selectively passes through the liquid crystal filter 12A. Is turned on, the light from the light source 17 is blocked.

  The light irradiator 10D has the same function as the light irradiator 10C by ON / OFF controlling the liquid crystal filter 12A in a state where the light is output 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 device 3H and the defect inspection device 3H has the same operation and effect as the sixth embodiment.

  In the defect inspection apparatus 3H, the cross nicol transmission inspection optical system can also be realized by turning off the light source 17, that is, stopping the light output from the light source 17.

  The defect inspection apparatus 3H adopts the transmission inspection optical system, but as in the seventh embodiment, even if the light irradiation unit 10D is disposed on the same side as the imaging unit 20A and the reflection inspection optical system is adopted. Good.

The ninth embodiment
In the first to eighth embodiments, the defect inspection apparatus in which the optical film having the linear polarization characteristic is inspected has been described. However, the optical film may not have linear polarization properties. As a ninth embodiment, a defect inspection apparatus in the case where an optical film having no linear polarization characteristic is an inspection object will be described. FIG. 12 is a schematic view of a defect inspection apparatus 3I according to the ninth embodiment.

  The defect inspection apparatus 3I is an apparatus for inspecting a defect of the optical film 100A having no linear polarization characteristic. Examples of the optical film 100A include the protective film 102, the protective film 103, and the retardation film shown in FIG.

  The defect inspection apparatus 3I is different from the defect inspection apparatus 3A of the first embodiment in that a linear polarization film (first linear polarization film) 40 is provided. The defect inspection apparatus 3I will be described focusing on this difference.

  The linear polarization film 40 is a film having linear polarization characteristics and has a polarization axis PA4. The linear polarizing film 40 is disposed between the optical film 100A and the imaging unit 20A so as to form a cross nicol with the linear polarizing film 12a of the liquid crystal filter 12. In FIG. 12, the linearly polarizing film 40 is disposed such that the Y direction coincides with the direction of the polarization axis PA4.

  A method of inspecting a defect of the optical film 100A using the defect inspection apparatus 3I will be described. When the defect inspection is performed, the 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, as in the first embodiment, the predetermined polarization state of the inspection light L is switched by controlling the liquid crystal filter 12 ON / OFF. In the imaging step, in synchronization with the switching of the predetermined polarization state of the inspection light L, the imaging unit 20A images the inspection region of the optical film 100A.

  Since the optical film 100A has no linear polarization characteristic, both the first polarized light and the second polarized light pass through the optical film 100A. The linearly polarized film 40 is disposed between the optical film 100A and the imaging unit 20A, the first polarized light passes through the linearly polarized film 40, and the second polarized light is blocked by the linearly polarized film 40.

  Therefore, also in the defect inspection apparatus 3I, the regular transmission inspection optical system and the cross nicol transmission inspection optical system are integrated, and the switching of the inspection optical system is performed by the 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 function and effect as the case of the first embodiment.

  The defect inspection apparatus 3I can be applied instead of the defect inspection apparatus 3A of the defect inspection system 1 of FIG. 1 when the inspection target conveyed by the conveyance unit 2 in FIG. 1 is the optical film 100A. The optical film manufacturing method including the defect inspection apparatus 3I and the defect inspection method using the defect inspection apparatus 3I has the same effects as those 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 when manufacturing the optical film 100A itself, for example, in the process of manufacturing the optical film 100, the film body You may be used for the defect inspection of the protective film 102 and the protective film 103 which are conveyed by the time of bonding to 101.

  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 polarization film 40 is further provided to have linear polarization characteristics. It is possible to carry out defect inspection of the optical film 100A. Specifically, as described in the fourth to seventh embodiments, when the light irradiation unit has the liquid crystal filter 12, a linear polarization film is provided between the optical film 100A having no linear polarization characteristic and the imaging unit. 40 may be arranged to form a cross nicol with the linearly polarizing film 12 a of the liquid crystal filter 12 as described in the ninth embodiment. As described in the eighth embodiment, when the light irradiation unit includes the linear polarization film 16 and the liquid crystal filter 12A, the linear polarization film 40 is interposed between the optical film 100A having no linear polarization characteristic and the imaging unit. , And may be arranged to form a cross nicol with the linear polarizing film 16. When the defect inspection apparatus according to the sixth to eighth embodiments includes the linear polarizing film 40 in order to perform the defect inspection of the optical film 100A, the linear polarizing film 40 corresponds to the first linear polarizing film and is linear. The polarizing film 16 corresponds to the second linear polarizing film.

  As described in the second embodiment, when the imaging unit has the liquid crystal filter 12, the linearly polarizing film 40 is described between the optical film and the light irradiation unit as described in the ninth embodiment. It may be arranged to form a crossed nicol with the twelve linearly polarizing films 12a.

  As described in the third embodiment, when both the light emitting unit and the imaging unit have the liquid crystal filter, the defect inspection of the optical film 100A is performed by the combination of the ON / OFF control of the liquid crystal filter of each of the light emitting unit and the imaging unit. Is possible.

  Although the optical film was illustrated as a film which does not have a polarization characteristic, the example of the film which does not have a polarization characteristic may be a separator film for batteries, etc.

  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 can be made without departing from the spirit of the present invention.

  In various illustrated embodiments, one control device controls the liquid crystal filter and the camera, but separate control devices may be provided for the liquid crystal filter and the camera. Although the above-mentioned various embodiments mainly explained a form which a defect inspection device provided with a control device, it may be a component different from a defect inspection device. For example, it may be a component of a defect inspection system, or may be an apparatus appropriately prepared by the user of the defect inspection apparatus.

  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.

  When the inspection object is a film having linear polarization characteristics, the film and the liquid crystal filter are set so that the predetermined polarization direction of the light passing through the filter portion and the polarization axis of the film are in parallel nicols or cross nicols. Described the form in which is placed. However, depending on the inspection object, the filter unit and the film may be arranged such that the predetermined polarization direction of the light passing through the filter unit and the polarization axis of the film are in a half cross nicol state. Alternatively, when the filter unit is a liquid crystal filter, the voltage applied to the liquid crystal filter is adjusted so that the predetermined polarization direction of the light passing through the filter unit and the polarization axis of the film are in a half cross nicol state. An examination may be performed. When the inspection object is a film having no linear polarization characteristic, the arrangement relationship between the filter section and the linearly polarizing film forming a pair may be a half cross nicol state as described above. In the case where the inspection object is a film having no linear polarization characteristic and the filter section is a liquid crystal filter, the predetermined polarization direction of the light passing through the filter section and the polarization of the linear polarization film paired with the filter section The inspection may be performed by adjusting the voltage applied to the liquid crystal filter so that the relationship with the axis is in a half cross nicol state.

  The various embodiments illustrated thus far may be combined with one another as appropriate. For example, the light irradiation unit described in one embodiment may be replaced with the light irradiation unit in another embodiment, or the imaging unit described in one embodiment may be replaced with the imaging unit in another embodiment. .

  3A, 3B, 3C, 3D, 3E, 3F, 3H, 3I ... defect inspection device, 10A, 10A, 10A2, 10B, 10C, 10D ... light irradiation part, 11 ... light source, 12 ... liquid crystal filter, 13 ... polarization Separation element 14 Optical path synthesis unit 15A First mirror (optical system) 15B Second mirror (optical system) 16 Linearly polarizing film 20A, 20B Imaging unit 21 Camera 40 Linearly polarized light Film (first linearly polarized film), 100, 100A: optical film (film), A: inspection area, L: inspection light.

Claims (17)

A film defect inspection device,
A light irradiator that outputs inspection light to be irradiated to an inspection area of the film;
An imaging unit for imaging the inspection area;
Equipped with
At least one of the light emitting unit and the imaging unit has a filter unit that selectively passes light in a predetermined polarization direction.
The filter unit is configured to be able to adjust the predetermined polarization direction.
Defect inspection device. The filter section has a liquid crystal filter configured by providing a linear polarizing film on one side of a liquid crystal cell.
The defect inspection apparatus according to claim 1. The film is an optical film having linear polarization characteristics,
The light emitting unit is
Light source,
The filter unit disposed between the light source and the film;
Have
The defect inspection apparatus according to claim 1. The film is an optical film having linear polarization characteristics,
The light emitting unit is
Light source,
A polarization separation element for separating light from the light source into first polarized light and second polarized light whose polarization directions are orthogonal to each other;
An optical path combining method which is disposed on the optical path of the second polarized light separated by the polarization separation element, and combines the optical path of the first polarized light separated by the polarization separation element with the optical path of the second polarized light Department,
An optical system for guiding the one polarized light separated by the polarization separation element to the optical path combining unit;
The filter unit disposed on the optical path of the first polarized light guided by the optical system;
Have
The film is disposed on the light path of the second polarized light.
The filter unit is switched between selectively passing the first polarized light and selectively passing the second polarized light.
The defect inspection apparatus according to claim 1. The light emitting unit is disposed between the polarization separation element and the optical path combining unit on the optical path of the second polarized light, and is disposed in a cross nicol state with respect to the film, and the second polarized light With a polarizing film that transmits light,
The defect inspection apparatus according to claim 4. The film is an optical film having linear polarization characteristics,
The imaging unit is
With the camera,
The filter unit disposed between the camera and the film;
Have
The defect inspection apparatus according to any one of claims 1 to 5. It further comprises a first linearly polarizing film disposed between the film and the imaging unit,
The film is a film having no linear polarization characteristic,
The light emitting unit is
Light source,
The filter unit disposed between the light source and the film;
Have
The defect inspection apparatus according to claim 1. It further comprises a first linearly polarizing film disposed between the imaging unit and the film,
The film is a film having no polarization property,
The light emitting unit is
Light source,
A polarization separation element for separating light from the light source into first polarized light and second polarized light whose polarization directions are orthogonal to each other;
An optical path combining unit, disposed on the optical path of the second polarized light, for 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 polarization separation element to the optical path combining unit;
The optical path of the second polarized light is disposed between the polarization separation element and the optical path combining unit, and is disposed in a cross nicol state with respect to the first linearly polarizing film, and the second polarized light is A second linear polarizing film to be passed through,
The filter unit disposed on the optical path of the first polarized light guided by the optical system;
Have
The film is disposed on the light path of the second polarized light.
The filter unit is switched between selectively passing the first polarized light and selectively passing the second polarized light.
The defect inspection apparatus according to claim 1. It further comprises a first linearly polarizing film disposed between the light irradiation unit and the film,
The film is a film having no polarization property,
The imaging unit is
With the camera,
The filter unit disposed between the camera and the film;
Have
The defect inspection apparatus according to claim 1. There are two light irradiators,
The first light emitting unit, which is one of the two light emitting units, is disposed on the opposite side of the imaging unit as viewed from the film,
The second light irradiation unit, which is the other of the two light irradiation units, is disposed on the same side as the imaging unit with respect to the film.
The defect inspection apparatus according to any one of claims 1 to 9. It is a defect inspection method of film, and
An inspection light irradiation step of irradiating an inspection light to the inspection area of the film by a light irradiation unit;
An imaging step of imaging the inspection area by an imaging unit;
Equipped with
At least one of the light emitting unit and the imaging unit has a filter unit that selectively passes light in a predetermined polarization direction.
The filter unit is configured to be able to adjust the predetermined polarization direction.
Defect inspection method. The filter section has a liquid crystal filter configured by providing a linear polarizing film on one side of a liquid crystal cell.
The defect inspection method according to claim 11. The film is an optical film having linear polarization characteristics,
The light irradiator outputs inspection light in the predetermined polarization direction by passing light from a light source through the filter.
In the inspection light irradiation step, the filter unit adjusts the predetermined polarization direction of the inspection light.
A defect inspection method according to claim 11 or 12. The film is an optical film having linear polarization characteristics,
The imaging unit images the inspection area of the film with a camera through the filter unit,
In the imaging step, the predetermined polarization direction that the filter unit passes is adjusted.
The defect inspection method according to any one of claims 11 to 13. The film is a film having no polarization property,
The light irradiator outputs inspection light in the predetermined polarization direction by passing light from a light source through the filter.
In the inspection light irradiation step, the filter unit switches the predetermined polarization direction of the inspection light;
In the imaging step, the imaging unit captures the inspection area through a first linear polarization film disposed between the film and the imaging unit.
A defect inspection method according to claim 11 or 12. The film is a film having no polarization property,
The light irradiator outputs inspection light in the predetermined polarization direction by passing light from a light source through the filter.
The imaging unit images the inspection area of the film with a camera through the filter unit,
In the inspection light irradiation step, the inspection light is irradiated to the film through a first linearly polarizing film disposed between the light irradiation unit and the film;
In the imaging step, the predetermined polarization direction that the filter unit passes is adjusted.
A defect inspection method according to claim 11 or 12.   The manufacturing method of a film including the defect inspection method as described in any one of Claims 11-16.