KR20130043547A - Apparatus for inspecting faulty of optical film - Google Patents

Abstract

PURPOSE: A device for inspecting defects of an optical film is provided to prevent duplicated investment in a separate inspection system according to a kind of the optical film by selectively changing a polarizing filter sheet whenever changing the kind of the optical film to be inspected, thereby reducing producing costs. CONSTITUTION: A device(200) for inspecting defects of an optical film comprises a lighting unit(220), a first PL filter unit(230), a photographing unit(240), an RED filter unit(250), and a second PL filter unit. A protective member is attached on one surface of the optical film. The lighting unit irradiates lights to the optical film. The first PL filter unit is interposed between the optical film and the lighting unit. The photographing unit is installed to be faced the light unit, thereby photographing the optical film. The RED filter unit is interposed between the optical film and the photographing unit. The second PL filter unit is installed between the optical film and the RED filter unit and optically matched with the first PL filter unit.

Description

Apparatus for inspecting faulty of optical film

preference

The present invention enjoys the priority of the 'fail inspection apparatus for FPR film' of Korean Patent Application No. 10-2011-0107642 filed on Oct. 20, 2011, the entire contents of which are incorporated herein by reference.

The present invention relates to a defect inspection apparatus for an optical film with a protective member, and more particularly, to a phase change of an optical film with a protective member, such as a PET film, on an FPR film used for a 3D display device. The present invention relates to an apparatus capable of inspecting optical defects (eg, 3D defects) caused by a defect.

Generally, it is known that human being feels three dimensional feeling because the right eye and the left eye perceive objects with time lag. That is, since the human eyes are spaced apart at a distance of about 65 cm, a person perceives a three-dimensional effect by binocular disparity generated while viewing images in slightly different directions.

Recently, interest in stereoscopic image display systems capable of realizing stereoscopic images by inputting images with parallax in both eyes has been increasing.

In general, stereoscopic image display devices are classified into three types such as a spectacular 3D display such as a shutter glasses, a micro polarizer, a patterned retarder and the like, a parallax barrier, a lenticular lens, A 3D display, and a holographic 3D display. Of these, stereoscopic image display devices have become popular as active systems (shutter glass systems) and passive systems (FPR systems).

In the active mode, the display alternately transmits the screen corresponding to the left and right at a very high speed, and accordingly, the stereoscopic glasses worn by the user are linked to the transmitted image and operate together. That is, the active method is a so-called 'time division method'. In the case of the left eye image, the right eye lens is closed when the left eye lens is opened, whereas the right eye image is a structure in which the left eye lens is closed when the right eye lens is opened. This approach has the advantage of being able to see the screen clearly, but it requires a high level of skill to synchronize the movement of the display with the glasses.

The passive method is a so-called "spatial partitioning method", and is capable of transmitting a left eye image and a right eye image having different polarization characteristics, and includes a display having a polarizing filter attached to the front and polarizing glasses worn by a user. Only the left eye image transmitted from the display is viewed through the left eye lens of the polarizing glasses and only the right eye image is viewed through the right eye lens of the polarizing glasses. This pass method is easy to implement without technical difficulties.

However, the polarizing filter used in the passive system can be attached to the polarizing plate so that the polarizing plate itself is patterned so as to correspond to the left and right eye image display units, or the polarizing plates are respectively associated with the left and right eye image display units Called Pattern-type Patterned Retarder (FPR), such as a patterned retardation plate (optical filter) having a patterned pattern.

In addition, patterned retarders are classified into glass-type and film-type depending on the type of substrate. However, since glass-type patterned lather is difficult to meet the trend of large-sized display, a patterned retarder film using an organic polymer film as a substrate has become popular in recent years.

However, the size of a pattern formed in the patterned retarder corresponds to the width of a pixel or a pixel and is very precise, and the shape of the pattern is generally formed in accordance with the row or column of the LCD. When the pattern is formed on the LCD, It is necessary to suppress the generation of dimensional defects in the manufacturing process of the patterned retarder and it is necessary to control the phase due to the damage of the liquid crystal layer and the culture layer of the patterned retarder There is a need to strictly control the defects due to the change (irrelevant to the defect of the display panel for 2D).

In addition, according to the conventional manufacturing method, the finished patterned retarder is delivered to the display panel manufacturer by attaching a protective film for reasons such as transportation failure, and the delivered patterned retarder is, for example, before it is finally attached to the panel. Because of using a so-called 'full line' inspection method in which two polarizers are visually inspected by crossing two polarizers, a defect rate is very high. Accordingly, there is a demand for the development of a system for inspecting defects due to phase change in the production line of the patterned retarder film.

On the other hand, a patterned retarder film corona-treats the surface of a base material in the manufacturing process, and makes it easy to print an alignment film etc. with respect to a base material. However, since the corona treatment process is a factor that lowers the optical straightness of the patterned retarder film finally produced, a solution is required.

The present invention has been conceived to solve the problems described above, the production process of the product to ensure the quality of the product with the mass production of the 3D film, that is, the product in the in-line (IN-LINE) before the optical film is wound on the winder An object of the present invention is to provide a defect inspection apparatus of an optical film capable of inspecting 3D defects.

According to another aspect, the present invention can be inspected by automatically compensating for the phase deviation of the protective film in the optical film manufactured in a state in which the protective film is pre-attached to the substrate in advance to compensate for the decrease in optical straightness by the corona treatment process The object is to provide an optical film defect inspection apparatus.

According to another aspect, the present invention provides a defect inspection of an optical film that can change the type of filter appropriately for such a panel in the system even if the optical films having optical properties that can be attached to the IPS panel or the TN panel, respectively, are changed. It is an object to provide a device.

In order to solve the above problems, a defect inspection apparatus of an optical film according to an exemplary embodiment of the present invention, the defect inspection apparatus of the optical film, the protective member is attached to one surface of the optical film; An illumination unit capable of irradiating light onto the optical film; A first PL filter unit disposed between the optical film and the illumination unit; A photographing unit provided to face the illumination unit so as to photograph the optical film; A RED filter unit disposed between the optical film and the photographing unit; And a second PL filter unit installed between the optical film and the RED filter unit and optically matched with the first PL filter unit.

Preferably, the optical film is a pattern relief film (FPR) in which L and R patterns having different optical axes are formed.

Preferably, the FPR is in an in-line state before the substrate on which the alignment layer and the liquid crystal layer are formed is wound on the winder in the traveling direction.

Preferably, the protective member is a polyethylene terephthalate (PET) film having an optical axis and a phase difference.

Preferably, the PET film is an oriented PET film oriented to have a controlled optical axis deviation or a non-oriented PET film in which the optical axis deviation is not controlled.

Preferably, the protective member is attached to the surface of the optical film that faces the lighting unit.

Preferably, the optical film travels at a predetermined speed; The photographing unit photographs a predetermined area in the width direction of the optical film represented by a value combined by the first and second PL filter units and the RED filter unit in a state where light is irradiated through the illumination unit. And a plurality of cameras for the purpose.

Preferably, the illumination unit may irradiate light over the entire width direction of the optical film.

Preferably, the lighting unit comprises: a plurality of LED lights installed in the lighting frame; And a light guide plate capable of converting light emitted from the LED lights into a surface light source and irradiating the optical film.

Preferably, the first PL filter unit comprises a polarizing filter.

Preferably, the polarizing filter has a single elongated polarizing filter sheet disposed long in the width direction of the optical film.

Preferably, the first PL filter unit selectively positions two polarizing filters having different characteristics with optimal angles corresponding to optical characteristics of the optical film on a focal line formed by the illumination unit and the photographing unit. It is provided with a first filter transfer member.

Preferably, the first filter transfer member may include: a first through slit and a second through slit disposed to be spaced apart from the optical film by a predetermined interval so as to be parallel to the optical film and through which light of the lighting unit may be transmitted, respectively. A first PL filter bracket formed; A first polarization filter sheet and a second polarization filter sheet respectively provided in the first through slit and the second through slit; And a guide part provided between the first filter bracket and the first filter frame to selectively move the first filter bracket.

Preferably, the RED filter unit includes a red filter that cuts short wavelengths and passes only long wavelengths to optimize defect detection of the photographing unit.

Preferably, the red filter consists of a circle.

Preferably, the red filter is integrally disposed at the end of the photographing unit.

Preferably, the photographing unit has a plurality of cameras; The red filter is fixedly installed at the lens end of each camera.

Preferably, the second PL filter unit has a second polarizing filter that can be optically matched with the polarizing filter.

Preferably, the second polarizing filter has a single elongated second polarizing filter sheet disposed long in the width direction of the optical film.

Preferably, the second PL filter unit may include first and second polarization filters having different characteristics with optimal angles corresponding to optical characteristics of the optical film on a focal line formed by the illumination unit and the photographing unit. And a second filter transfer member that can be positioned selectively.

Preferably, the second filter transfer member may include: a first through slit and a second through slit disposed to be spaced apart from the optical film by a predetermined distance so as to be parallel to the optical film and through which light of the lighting unit may be transmitted, respectively. A second filter bracket formed; A first polarization filter sheet and a second polarization filter sheet respectively provided in the first through slit and the second through slit; And a second guide part provided between the second filter bracket and the second filter frame to selectively move the second filter bracket.

Preferably, the apparatus further includes a marking unit capable of marking the presence or absence of a defect on the surface of the optical film that travels to correspond to the positional information of the defect shown in the image photographed by the photographing unit.

Preferably, the control unit for calculating and storing the position information of the defect displayed on the images taken by the imaging unit; And a display unit capable of displaying the respective images.

The defect inspection apparatus of the optical film according to a preferred exemplary embodiment of the present invention, for example, in the production of an optical film such as a film-type patterned retarder (FPR) film, in order to improve the process productivity protective film such as PET film In the case of selecting a process pre-attached to the substrate of the optical film, it is possible to detect a 3D defect in a gray section generated when the image is reversed because the axis between the polarizing plate and the CPL is distorted.

The defect inspection apparatus of the optical film according to an exemplary embodiment of the present invention, when using a non-oriented PET film as a protective film in order to reduce manufacturing cost and maintain the characteristic value, Image reversal often occurs due to different phase changes, or defect detection of FPR overcomes difficulties due to non-orientation of the protective film.

Oriented PET protective film refers to a film produced by controlling the optical axis deviation by adjusting the line speed and the tension of the film when producing the protective film, non-oriented PET protective film is a product produced without considering the optical axis deviation Compared to the film, the raw materials and production process are the same, but the optical properties are not uniform, and the production speed can be increased indefinitely, which is relatively inexpensive.

An apparatus according to a preferred exemplary embodiment of the present invention detects a defect before the optical film is wound on the winder in the manufacturing line of the optical film produced in the order of protective film (non-orientated PET) => alignment layer => liquid crystal => release film. can do. In addition, it is possible to inspect all of the defects of the optical film pre-attached to the orientation angle protection film or non-orientation protection film as a protective member. In the film region determined to be defective, a defective indication mark may be printed.

In the defect inspection apparatus of the optical film according to an exemplary embodiment of the present invention, the first PL filter unit located on the illumination side and the second PL filter unit located on the camera side respectively correspond to the IPS panel, TN panel Different combinations of optical films may be used.

The defect inspection apparatus of the optical film which concerns on this invention has the following effects.

First, selectively changing a polarizing filter sheet having optical properties corresponding to the optical properties of the optical film to be inspected whenever the type of optical film to be inspected changes, such as an optical film to be used for an IPS panel or an optical film to be used for a TN panel. Thus, the production cost can be reduced by avoiding the overlapping investment of separate inspection systems according to the type of optical film (that is, the polarizing filter is a combination of a pair so as to correspond to the optical film for IPS panel or the optical film for TN panel respectively. Is present).

Secondly, the 3D defects (e.g., the liquid crystal layer has not been dug but the shape of the finger presses, but the image is not pressed but the image is reversed through the optical axis combination of the camera side PL filter and the illumination side PL filter are black without damaging the image inverted). Gray or non-white stain defects can be inspected.

Third, since the film can be inspected for defects before being wound on the winder in the production process of the FPR film, pre-determination can be performed according to the inspection type, thereby increasing production efficiency and reducing production cost.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in detail with reference to the following drawings, which illustrate preferred embodiments of the present invention, and thus the technical idea of the present invention should not be construed as being limited thereto.
1 is a conceptual diagram schematically showing a main configuration of a defect inspection apparatus of an optical film according to a preferred exemplary embodiment of the present invention.
Figure 2 is a graph showing the phase difference and optical axis distribution of the non-oriented PET protective film fabric attached to the optical film to be inspected by the inspection apparatus according to an exemplary embodiment of the present invention.
3 is a schematic view showing the configuration of a defect inspection apparatus for an optical film according to another exemplary embodiment of the present invention.
4 is an enlarged view of a main part of FIG. 3.
5 is a plan view of Fig.
FIG. 6 is a left side view of the first PL filter unit illustrated in FIGS. 3 and 4.
FIG. 7 is a right side view of the second PL filter unit illustrated in FIGS. 3 and 4.
FIG. 8 is a conceptual view illustrating the operation of first and second PL filter units of a defect inspection apparatus for an optical film according to an exemplary embodiment of the present invention.
9 is an enlarged view of a portion of the marking unit shown in FIG. 3.
10A and 10B are photographs showing examples of 3D defects photographed by a photographing unit of a defect inspection apparatus of an optical film according to a preferred exemplary embodiment of the present invention.
10C is a view showing a photograph of a portion of a polarizing film in which unevenness occurs and a phase difference graph of such a film.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

1 is a conceptual diagram schematically showing a main configuration of a defect inspection apparatus of an optical film according to a preferred exemplary embodiment of the present invention.

Referring to FIG. 1, a defect inspection apparatus 70 of an optical film according to an exemplary embodiment of the present invention is for inspecting a defect of an optical film 10 having a protective member 12 attached thereto. Illumination unit 72 capable of irradiating light to the light 10, the first PL filter unit 74 disposed between the optical film 10 and the illumination unit 72, and the illumination unit so that the optical film 10 can be photographed An imaging unit 76 disposed opposite 72, a RED filter unit 77 disposed between the optical film 10 and the imaging unit 76, and between the optical film 10 and the RED filter unit 77 A second PL filter unit 78 disposed and optically matched with the first PL filter unit 74.

The optical film 10 is a patterned retard film (FPR) in which L and R patterns having different optical axes are formed. The FPR type optical film 10 has the base material 14 and the orientation layer 16 and the liquid crystal layer 18 are formed on the surface of the base material 14 opposed to the surface to which the protective member 12 is attached have. As will be described later, the patterned retard film or optical film 10 is preferably in an in-line state before being wound on a winder (not shown) while the film is traveling. In an alternative embodiment, those skilled in the art will fully appreciate that the defect inspection apparatus 70 of the optical film may be applied to a finished patterned retarder film or an optical filter cut to such a size.

The base material 14 of the optical film 10 is made of, for example, a cycloolefin polymer such as triacetylcellulose, polyacrylate, polyethylene terephthalate, polycarbonate, polyethylene, norbornene derivatives and the like. It is preferable that the base material 14 is an isotropic base material having almost no in-plane retardation and thickness retardation or only a retardation value in the thickness direction without in-plane retardation. On the other hand, the width of the optical film 10 is substantially determined by the width of the substrate 14, and can be variously configured with a width of, for example, 1200 mm to 2200 mm.

The orientation layer 16 of the optical film 10 has an alignment treatment method and an alignment direction in which the first alignment film and the second alignment film are different from each other. For example, if a 1st orientation film is a photo-alignment film, a 2nd alignment film will use a rubbing alignment film, and if a 1st alignment film is a rubbing alignment film, a 2nd alignment film will use a photo alignment film. When an alignment film having a different processing method is used, since one alignment film processing method does not affect other alignment films, an alignment film having different alignment directions can be easily formed without going through a complicated process such as a mask or a photoresist. For example, even if the rubbing alignment film is irradiated with UV polarized light, the alignment direction of the alignment film is not changed, and the case where the rubbing process is performed on the photo alignment film is also reversed. Therefore, after the rubbing alignment film is applied, the rubbing process is performed in the first alignment direction to form the rubbing alignment film, the polymer film for the photo alignment film is coated thereon at regular intervals thereon, and the polarized film is polarized in the second alignment direction different from the first alignment direction By the method of irradiating UV polarized light, the first alignment film and the second alignment film having different alignment directions can be formed. It is preferable that the alignment directions of the first alignment film and the second alignment film are perpendicular to each other.

The liquid crystal layer 18 of the optical film 10 is formed on the first alignment film and the second alignment film and is patterned into a first region oriented by the first alignment film and a second region oriented by the second alignment film. When the liquid crystal material is coated on the alignment film, the liquid crystal material is aligned along the alignment direction of the alignment film. Since the first and second alignment films have different alignment directions, the liquid crystal layer 18 formed thereon is also aligned in different directions. The liquid crystal layers 18 are alternately formed, and as a result, a patterned retardation layer can be formed. The pattern of the liquid crystal layer 18 is determined according to the application pattern of the second alignment film. For example, when the second alignment film is in a stripe shape, a liquid crystal layer of a stripe pattern is formed, and when the second alignment film is applied in a checkerboard pattern, a checkerboard pattern liquid crystal layer is formed.

On the other hand, the liquid crystal layer 18 may have various retardations depending on its thickness, and may preferably be a quarter-wave retardation layer. When the liquid crystal layer 18 is a quarter-wave retardation layer, the polarized light is converted into circularly polarized light when the incident light source is linearly polarized light and linearly polarized light when the incident light source is circularly polarized light. This is because it is useful for stereoscopic image display.

The protection member 12 is attached to the surface of the optical film 10 which faces the illumination unit 72 as mentioned above. The protective member 12 is subjected to corona treatment to increase the binding force between the substrate 14 and the culture layer 16 during the manufacturing of the FPR 10, which is finally produced by the corona treatment FPR (10) In order to prevent deterioration of the optical straightness,), the culture layer 16 is first attached to one surface of the substrate 14 before the culture layer 16 is formed. That is, if the base material 14 with the protective member 12 is corona-treated, the problem of degradation of the optical linear characteristic of the finally produced FRP 10 can be solved.

The protective member 12 includes a polyethylene terephthalate (PET) film having a specific optical axis and a retardation. The PET film may be an oriented PET film oriented to have a relatively uniform optical axis deviation by controlling the speed of the production line and the tension of the film while controlling the optical axis deviation while producing the film. In this embodiment, however, And relatively inexpensive non-oriented PET films are used. The non-oriented PET film is produced through the same production process using the same resin as the oriented PET film. Alternatively, the person skilled in the art will appreciate that the protective member 12 can be replaced by various plastic films other than PET films.

Figure 2 is a graph showing the phase difference and optical axis distribution of the non-oriented PET protective film fabric attached to the optical film to be inspected by the inspection apparatus according to an exemplary embodiment of the present invention.

As shown in FIG. 2, those skilled in the art will understand that the phase difference and optical axis of the non-oriented PET protective film may exhibit different characteristics depending on the measurement position or the lot produced. Generally, in the same lot where the same speed is maintained during the production of the non-oriented PET protective film, the optical axis can be kept relatively constant at the side and center, but if the lot is changed, the optical axis and phase difference are not the same do.

Referring to FIG. 1, the illumination unit 72 is for irradiating light in the direction of the optical film 10 to provide the light necessary for the imaging unit 76 to photograph the surface of the optical film 10. For example, use LED lighting. Of course, those skilled in the art will appreciate that the lighting unit 72 may use illumination, such as fluorescent, incandescent or the like, for the LED illumination.

The first PL filter unit 74 is disposed between the optical film 10 and the illumination unit 72, and can perform a polarizing function at a specific angle corresponding to the type of optical film 10 to be inspected. It includes a PL (polarization) filter. That is, the first PL filter unit 74 may be, for example, depending on the case where the optical film 10 is an FPR used for an In-Plane Swithcing (IPS) panel and an FPR used for a twisted nematic (TN) panel. PL filters with different specific angles can be used. The polarization filter of the first PL filter unit 74 has a function of supplementing the function of the RED filter unit 77 and limiting the saturation of light according to the phase change.

The photographing unit 76 has a light axis irradiated from the illumination unit 72 by the first PL filter unit 74 and the optical axis of the optical film 10 and / or the optical axis of the protective member 12 and the RED filter. For photographing the surface of the optical film 10 optimized by light compensated or polarized through the unit 77 and the second PL filter unit 78, a camera 71 is included.

The RED filter unit 77 includes a RED (red) filter 75 disposed between the optical film 10 and the imaging unit 76. The RED filter 75 cuts the short wavelength and passes only the long wavelength to optimize the defect detection of the monochrome camera of the photographing unit 76. That is, the RED filter 75 transmits infrared rays and removes blue light. The RED filter 75 is to emphasize the contrast. In addition, as described below, the RED filter 75 is preferably configured in a substantially circular shape so that it can be fixedly installed at the front end of the camera 71 of the photographing unit 72.

The second PL filter unit 78 includes a second polarization filter that is structurally and functionally identical to the polarization filter of the aforementioned first PL filter unit 74. That is, the second polarization filter of the second filter unit 78 also has a function of supplementing the function of the RED filter of the RED filter unit 77 and limiting the saturation of light according to the phase change of the optical film 10. According to the case where the optical film 10 is an FPR used for an In-Plane Swithcing (IPS) panel and an FPR used for a twisted nematic (TN) panel, a second polarizing filter having a different specific angle is used. Therefore, when the first PL filter unit 74 uses the first PL filter having the optical characteristic corresponding to the IPS panel, the second PL filter unit 78 also has the second optical characteristic having the same optical characteristic as the first PL filter. Use a PL filter. The same applies to the optical film 10 to be used for the TN panel.

3 is a schematic view showing the configuration of a defect inspection apparatus for an optical film according to another preferred exemplary embodiment of the present invention, FIG. 4 is an enlarged view of a main part of FIG. 3, and FIG. 5 is of FIG. 3. Top view. The same components as those described in FIG. 1 are the same members with the same functions.

3 to 5, the defect inspection apparatus 200 of the optical film according to the present embodiment is similar to the above-described embodiment, in a state in which the protective film 12 is pre-attached to one surface of the substrate 14. The alignment layer 16 and the liquid crystal layer 18 are formed on the other side of the substrate 14 to produce an optical film 10 such as FPR, that is, the optical film 10 is wound on a winder (not shown). In the IN-Line state before it is, it is for examining the 3D defect by the phase change of the protective film 12 and / or the optical film 10. FIG. Therefore, the defective data inspected by the inspection apparatus 200 can be confirmed in real time, and the necessary measures can be immediately taken.

In the defect inspection apparatus 200 of the optical film according to the present exemplary embodiment, an optical film that has a protective member 12 attached to one surface thereof and travels at a predetermined speed along a plurality of rollers 104 installed on the main frame 102 ( 10 is a state in which light is irradiated through the lighting unit 220 for irradiating light, the first PL filter unit 230 and the lighting unit 220 installed between the lighting unit 220 and the optical film 10. A plurality of cameras 242 having a plurality of cameras 242 for shooting a predetermined area in the width direction of the optical film 10, a plurality of cameras respectively provided at the tip of each camera 242 of the shooting unit 240 The optical properties of the RED filter unit 250 including the filters 252, the RED filter unit 250, and the optical film 10 may be matched with the optical properties of the first PL filter unit 230. And a second PL filter unit 260.

The illumination unit 220 is for irradiating light over the whole width direction of the optical film 10, and it is preferable to use an LED in view of the life of an illumination, stability of brightness, maintainability, etc.

The lighting unit 220 emits from the lighting module 224, the LED 122, which includes a lighting frame 225 installed across the main frame 102, and a plurality of LEDs 222 installed on the lighting frame 225. The light guide plate 226 having a length larger than the width of the optical film 10, the illumination module 224 and the light guide plate 226 may be installed to convert the light into a surface light source and irradiate the optical film 10. The lighting case 228 and a heat dissipation member 227 having a fin structure for dissipating heat generated from the LED 222 to the outside. It will be appreciated by those skilled in the art that the number or arrangement of LEDs 222 of the lighting unit 220 may be replaced by other lighting in a known manner.

The photographing unit 240 is for continuously photographing the optical film 10 traveling, and includes a plurality of cameras 242 having a conventional structure and resolution. The plurality of cameras 242 are spaced apart from each other at predetermined intervals D3 (see FIG. 5) in the width direction of the optical film 10. Here, the interval D3 may be determined such that each of the cameras 242 can photograph the overlap of the width of the optical film 10 slightly, but it is preferably selected so that such overlap does not appear. Each of the cameras 242 is installed in the camera frame 245 disposed parallel to the width direction of the optical film 10 across the main frame 102. Each of the cameras 242 has a resolution of approximately 100 micrometers, for example, and a known camera having a capability of capturing 900 to 1200 images per second may be used. The number of installations of the cameras 242 installed in the photographing unit 240 may be arranged differently depending on the length of the width of the optical film 10 used for the resolution of each camera 242. In addition, the apparatus 200 according to the present exemplary embodiment may provide a sufficient number of cameras 242 and may turn off a camera that does not need operation so as to correspond to the width of the optical film 10 to be inspected.

FIG. 6 is a left side view of the first PL filter unit illustrated in FIGS. 3 and 4.

3, 4, and 6, the first PL filter unit 230 includes a polarization filter for polarizing light emitted from the illumination unit 220. As will be described later, the polarizing filter includes a single elongated filter sheet 232 and 234 disposed long in the width direction of the optical film 10.

The apparatus 200 according to a preferred exemplary embodiment of the present invention can inspect the FPR film used for the In-Plane Swithcing (IPS) panel or the FPR film used for the twisted nematic (TN) panel, respectively. Therefore, the apparatus 200 should use a polarizing filter (sheet) having different specific angles as the first PL filter unit 230 to correspond to the type of the optical film 10 to be inspected. For example, an FPR film for an IPS panel may be coated with an alignment film at an angle of 45 degrees, a mask may be mounted on an exposure machine, and UV irradiation to absorb energy may cause the alignment layer to rotate at an angle of 235 degrees, and the liquid crystal thereon. The layers were applied to form a patterned pair with a final angle of 45 degrees and 235 degrees, while the FPR film for the TN panel applied an alignment film at an angle of 0 degrees, energized and rotated at a 90 degree angle to form a liquid crystal layer. Apply to form a pattern pair at an angle of 0 degrees and 90 degrees. Accordingly, the first PL filter unit 230 needs to use filter sheets 232 and 234 having different inherent angles depending on the type of angle formed by the pattern pairs of the optical film 10 to be inspected. . Therefore, the apparatus 200 according to the present embodiment makes it possible to select any one between two filter sheets 232 and 234 having a unique polarization angle suitable for the IPS panel and the TN panel as described above. To this end, the device 200 has a first filter conveying member 236. That is, the first filter transfer member 236 has an optimal angle corresponding to the optical characteristics of the optical film 10 on the focal line FL (see FIG. 5) formed by the illumination unit 220 and the imaging unit 240. The first filter sheet 232 and the second filter sheet 234 having different characteristics may be selectively positioned. The specific working principle is described in detail below.

As shown in FIG. 6, the first PL filter unit 230 may include a first through slit 238a each formed long in the width direction of the optical film 10 so that light of the illumination unit 220 may be transmitted. The first filter sheet 232 and the second filter 232 are provided to respectively block the first filter bracket 238, the first through slit 238a, and the second through slit 238b, which are provided to be movable. A plurality of fixing pieces 238c for fixing the edges of the first filter sheet 232 and the second filter sheet 234 to the first filter bracket 238 while the second filter sheet 234 is positioned. It is provided. In addition, the first filter bracket 238 further includes a third through slit 238d. This third through slit 238d is a spare space for attaching a polarizing filter sheet or other type of test polarizing filter sheet suitable for PN panels, other types of optical filters corresponding to panels other than IPS panels as described above. to be. Therefore, the third through slit 238d is typically used in a state where no polarization filter sheet is attached.

The first filter transfer member 236 has guide blocks 231 which are respectively provided at both ends of the first filter bracket 238 and coupled to the guide rail 106 and the guide rod 108 installed at the main frame 102. Equipped. The guide block 231 has a bracket installation part 235 on which one end of the first filter bracket 238 is installed, a rail coupling part 237 coupled to the guide rail 106, and a rod insertion part into which the guide rod 108 is inserted. The part 233 is provided. The first filter transfer member 236 is preferably configured such that its position can be adjusted by pneumatic or hydraulic pressure.

As shown in FIG. 8, for example, when the inspection target optical film 10 is a film used in an IPS panel, the first filter sheet 232 installed in the first through slit 238a is the focal line FL. ). However, when the inspection target optical film 10 is a film used for the TN panel, the first filter transfer member 236 moves the first filter bracket 238 in the direction of the arrow "A" to the second through slit 238b. ) Allows the second filter sheet 234 to be positioned at the focal line FL.

Referring to FIG. 4, the RED filter unit 250 irradiates the illumination unit 220 to cut short wavelengths of light passing through the optical film 10 and to pass only the long wavelengths, thereby optimizing defect detection of the photographing unit 240. And a filter 252. The red filter 252 is preferably composed of a circular filter module. The circular filter module 258 is fixedly installed at the end of each camera 242 of the photographing unit 240. Those skilled in the art will fully understand that the module structure of the RED filter unit 250 and the installation structure for the camera 242 may be appropriately selected or changed within a range that does not impair optical characteristics. In addition, those skilled in the art will understand that the connection between the filter module 158 and the end of the camera 242 of the photographing unit 240 may be made by various methods such as screwing, fitting, coupling, connectors, and the like.

FIG. 7 is a right side view of the second PL filter unit illustrated in FIGS. 3 and 4.

3, 4, and 7, the second PL filter unit 260 includes a second polarization filter that is structurally and functionally identical to the polarization filter of the aforementioned first PL filter unit 230. That is, the second polarization filter of the second filter unit 260 also has a function of supplementing the function of the RED filter of the RED filter unit 250 and limiting the saturation of light according to the phase change of the optical film 10. According to the case where the optical film 10 is an FPR used for an In-Plane Swithcing (IPS) panel and an FPR used for a twisted nematic (TN) panel, a second polarizing filter having a different specific angle is used. Therefore, when the first PL filter unit 230 uses a first PL filter having an optical characteristic corresponding to the IPS panel, the second PL filter unit 260 also has a second optical characteristic having the same optical characteristic as the first PL filter. Use a PL filter. The same applies to the optical film 10 to be used for the TN panel.

Therefore, the second PL filter unit 260 needs to use filter sheets 262 and 264 having different inherent angles depending on the type of angle formed by the pattern pairs of the optical film 10 to be inspected. . Therefore, the apparatus 200 according to the present embodiment makes it possible to select any one between two filter sheets 262 and 264 having a unique polarization angle suitable for the IPS panel and the TN panel as described above. To this end, the device 200 has a second filter conveying member 266. That is, the second filter transfer member 266 has an optimal angle corresponding to the optical characteristics of the optical film 10 on the focal line FL (see FIG. 5) formed by the illumination unit 220 and the imaging unit 240. The first filter sheet 262 and the second filter sheet 264 having different characteristics may be selectively positioned. The specific working principle is described in detail below.

As shown in FIG. 7, the second PL filter unit 260 may include a first through slit 268a formed to extend in the width direction of the optical film 10 so that the light of the illumination unit 220 may be transmitted, respectively. The first filter sheet 262 and the second filter bracket 268 and the second filter bracket 268, the first through slit 268a and the second through slit 268b are respectively provided so as to block the second through slit 268b. A plurality of fixing pieces 268c for fixing the edges of the first filter sheet 262 and the second filter sheet 264 to the first filter bracket 268 while the second filter sheet 264 is positioned. It is provided. In addition, the first filter bracket 268 further includes a third through slit 268d. This third through slit 268d is a spare space for attaching a polarizing filter sheet or other type of test polarizing filter sheet suitable for PN panels, other types of optical filters corresponding to panels other than IPS panels as described above. to be. Therefore, the third through slit 268d is typically used in a state where no polarization filter sheet is attached.

The second filter conveying member 266 is provided with guide blocks 261 respectively provided at both ends of the second filter bracket 268 and coupled to the guide rail 106 and the guide rod 108 installed at the main frame 102, respectively. Equipped. The guide block 261 includes a bracket mounting portion 265 in which one end of the second filter bracket 268 is installed, a rail coupling portion 267 coupled to the guide rail 106, and a rod insertion portion in which the guide rod 108 is inserted. The part 263 is provided. The first filter transfer member 266 is preferably configured such that its position can be adjusted by pneumatic or hydraulic pressure.

FIG. 8 is a conceptual view illustrating the operation of first and second PL filter units of a defect inspection apparatus for an optical film according to an exemplary embodiment of the present invention.

As shown in FIG. 8, for example, the inspection target optical film 10 is a film used for an IPS panel, and the first through slit 238a of the first filter bracket 238 of the first filter unit 230. When the first filter sheet 232 installed at the second filter sheet 232 is positioned at the focal line FL, the second filter bracket 268 of the second filter unit 260 is also positioned at the first through slit 268a. The sheet 262 is positioned on the focal line FL, so that the first filter sheet 232 of the first filter unit 230 and the first filter sheet 262 of the second filter unit 260 have the same optical characteristics. Is used to inspect the surface of the corresponding optical film 10. However, when the inspection target optical film 10 is the optical film 10 used for the TN panel, the first filter bracket 238 is moved in the direction of the arrow "A" by the first filter transfer member 236, and the first When the second filter sheet 234 installed in the second through slit 238b is positioned on the focal line FL, the second filter conveying member 266 also conveys the second filter bracket 268 in the direction indicated by arrow "B". The second filter sheet 264 located in the second through slit 268b of the second filter unit 260 is positioned in the focal line FL.

3, the defect inspection apparatus 200 of the optical film according to the preferred embodiment of the present invention is based on the position information of the defect shown in each image taken by the cameras 242 of the photographing unit 240 A marking unit 190 may be further provided on the surface of the optical film 10 that corresponds to the driving unit. The marking unit 190 is controlled by a control unit described later.

9 is an enlarged view of the marking unit part shown in FIG. 3.

3 and 9, the marking unit 190 is disposed approximately 20 mm apart from the optical film 10 so that a marker having a predetermined pattern (eg, a circular annular shape) can be marked on corresponding position information of the optical film. Injectors 192 having a plurality of annular spouts.

Each injector 192 intermittently switches the ink stored in the ink reservoir 194 by pneumatic pressure by selectively turning on and off the marking body 196, in which the ink reservoir 194, in which ink can be stored, can be installed, and the jet port. A solenoid valve 198 can be provided. The ink reservoir 194 has a cartridge structure that can be detachably coupled to the marking body 196. Thus, when the ink in the ink reservoir 194 is exhausted, it can be replaced with a new cartridge.

The defect inspection apparatus 200 of the optical film according to the exemplary embodiment of the present invention, as described above, the control unit that can calculate and store the position information of the defect displayed on the images taken by the photographing unit 240 (Not shown), and a display unit (not shown) capable of displaying respective images.

It will be understood by those skilled in the art that the control unit may be set up to be related to the overall flow of performing the functions of the device 200, such as the rotation of the second PL filter unit 260 described above.

10A and 10B are photographed by the camera 242 of the photographing unit 240 of the defect inspection apparatus 200 of the optical film according to a preferred exemplary embodiment of the present invention and stored in the control unit to be displayed on the display unit, respectively. It is a figure which shows the example of the given 3D defect.

As shown in FIGS. 10A and 10B, each image photographed by the camera 242 of the photographing unit 240 is grayed out at a predetermined portion of the vertical black and white stripes (continuous state of the L pattern and the R pattern) in the vertical direction. Shape defects (stainless defects in which the liquid crystal layer did not squeeze, but seemed to be pressed with a finger, and gray or non-black stains without being damaged enough to reverse the image) were confirmed.

10C shows a photograph of a portion of a polarizing film in which unevenness occurs and a phase difference graph of such a film.

Referring to FIG. 10C, it can be seen that the retardation of the optical film in which the unevenness occurs has a much higher retardation than the normal value region.

10... Optical film 12... Protection
14 ... Description 16. Alignment layer
18 ... Liquid crystal layer 190... Marking Unit
200 ... . Defect inspection apparatus 220. Lighting unit
230... First PL filter unit 240... Shooting unit
250... RED filter unit 260.. 2nd PL filter unit

Claims (23)

In the defect inspection apparatus of the optical film,
A protective member is attached to one surface of the optical film;
An illumination unit capable of irradiating light onto the optical film;
A first PL filter unit disposed between the optical film and the illumination unit;
A photographing unit provided to face the illumination unit so as to photograph the optical film;
A RED filter unit disposed between the optical film and the photographing unit; And
And a second PL filter unit which is provided between the optical film and the RED filter unit and is optically matched with the first PL filter unit.
The method according to claim 1,
The optical film is a defect inspection apparatus of the optical film, characterized in that the patterned retard film (FPR) formed with L and R patterns having different optical axes.
The method according to claim 2,
The FPR defect inspection apparatus of the optical film, characterized in that in the in-line (IN-Line) state before the winding on the winder while the substrate on which the alignment layer and the liquid crystal layer is formed.
The method according to any one of claims 1 to 3,
The protective member is a defect inspection apparatus of an optical film, characterized in that the polyethylene terephthalate (PET) film having a phase difference with the optical axis.
The method of claim 4,
And the PET film is an oriented PET film oriented to have a controlled optical axis deviation or an unoriented PET film whose optical axis deviation is not controlled.
The method according to claim 1,
And the protective member is attached to a surface of the optical film that faces the illumination unit.
The method according to claim 1,
The optical film travels at a predetermined speed;
The photographing unit photographs a predetermined area in the width direction of the optical film represented by a value combined by the first and second PL filter units and the RED filter unit in a state where light is irradiated through the illumination unit. And a plurality of cameras for the defect inspection apparatus of the optical film.
The method according to claim 1,
The illuminating unit can irradiate light over the entire width direction of the optical film, wherein the defect inspection apparatus of the optical film.
The method according to claim 8,
The lighting unit is:
A plurality of LED lights installed in the light frame; And
And a light guide plate for converting light emitted from the LED lights into a surface light source and irradiating the optical film.
The method according to claim 1,
And said first PL filter unit comprises a polarizing filter.
The method of claim 10,
The polarizing filter includes a single elongated polarizing filter sheet disposed long in the width direction of the optical film, characterized in that the defect inspection apparatus of the optical film.
The method according to claim 1,
The first PL filter unit may selectively position two polarizing filters having different characteristics with optimal angles corresponding to optical characteristics of the optical film on a focal line formed by the illumination unit and the photographing unit. It is provided with the 1st filter feed member, The defect inspection apparatus of the optical film characterized by the above-mentioned.
The method of claim 12,
The first filter transfer member is:
A first PL filter bracket disposed to be spaced apart from the optical film by a predetermined distance so as to be parallel to the optical film, and having a first through slit and a second through slit through which the light of the illumination unit can be transmitted, respectively;
A first polarization filter sheet and a second polarization filter sheet respectively provided in the first through slit and the second through slit; And
And a guide portion provided between the first filter bracket and the first filter frame to selectively move the first filter bracket.
The method according to claim 1,
And the RED filter unit includes a red filter that cuts short wavelengths and passes only long wavelengths to optimize defect detection of the photographing unit.
The method according to claim 14,
The red filter is a defect inspection apparatus of the optical film, characterized in that configured in a circle.
The method according to claim 14,
And the red filter is integrally disposed at the end of the photographing unit.
The method according to claim 14,
The photographing unit includes a plurality of cameras;
The red filter is a defect inspection apparatus of the optical film, characterized in that fixed to the lens end of each camera.
The method according to claim 1,
The second PL filter unit includes a second polarizing filter that can be optically matched with the polarizing filter.
19. The method of claim 18,
The second polarizing filter includes a single elongated second polarizing filter sheet which is disposed to be long in the width direction of the optical film.
The method according to claim 1,
The second PL filter unit selectively positions first and second polarization filters having different characteristics with optimal angles corresponding to optical characteristics of the optical film on a focal line formed by the illumination unit and the photographing unit. The 2nd filter feed member which can be made is provided, The defect inspection apparatus of the optical film characterized by the above-mentioned.
The method of claim 20,
The second filter transfer member is:
A second filter bracket disposed to be spaced apart from the optical film by a predetermined interval so as to be parallel to the optical film, and having a first through slit and a second through slit through which light of the illumination unit can be transmitted, respectively;
A first polarization filter sheet and a second polarization filter sheet respectively provided in the first through slit and the second through slit; And
And a second guide part provided between the second filter bracket and the second filter frame to selectively move the second filter bracket.
The method according to claim 1,
And a marking unit capable of marking the presence or absence of a defect on the surface of the optical film traveling to correspond to the positional information of the defect shown in the image photographed by the photographing unit.
The method according to claim 1,
A control unit capable of calculating and storing position information of defects displayed on the images photographed by the photographing unit; And
And a display unit capable of displaying the respective images.

Images