JP6168834B2 - Optical film defect determination method - Google Patents

Optical film defect determination method Download PDF

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JP6168834B2
JP6168834B2 JP2013094023A JP2013094023A JP6168834B2 JP 6168834 B2 JP6168834 B2 JP 6168834B2 JP 2013094023 A JP2013094023 A JP 2013094023A JP 2013094023 A JP2013094023 A JP 2013094023A JP 6168834 B2 JP6168834 B2 JP 6168834B2
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ギュ リ ウン
ギュ リ ウン
ウー キム ジョン
ウー キム ジョン
ジュン ペ ソン
ジュン ペ ソン
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
    • G01N21/896—Optical defects in or on transparent materials, e.g. distortion, surface flaws in conveyed flat sheet or rod
    • G—PHYSICS
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    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
    • G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/21—Polarisation-affecting properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/0002—Inspection of images, e.g. flaw detection
    • G06T7/0004—Industrial image inspection

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Description

本発明は、光学フィルムの不良検出方法に関するものである。より詳しくは、光学フィルムに対して、良品に対する不良判定を低減することができる不良検出方法に関するものである。   The present invention relates to an optical film defect detection method. More specifically, the present invention relates to a defect detection method capable of reducing defect determination for a non-defective product with respect to an optical film.

近来、液晶ディスプレイ、有機発光ディスプレイ、電界放出ディスプレイ(ＦＥＤ）、プラズマ表示パネル(ＰＤＰ）など、多様な画像表示装置が幅広く開発され用いられている。   Recently, various image display devices such as a liquid crystal display, an organic light emitting display, a field emission display (FED), and a plasma display panel (PDP) have been widely developed and used.

その一方で、画像表示装置は、市場に出庫される前の製造過程中で多様な不良が発生し得るため、数多くの検査過程を経るようになるが、画像表示装置の中でも最も多く用いられる部品の一つが偏光フィルム、位相差フィルムなどの様々な光学フィルムであり、それ故に、光学フィルムの欠陥は画像表示装置の不良の主な原因の一つである。光学フィルムの欠陥を検出することは、先ず欠陥であるか否かを判別して正確な判定を行い、その後、欠陥と判別されると欠陥の修復(repair）又は廃棄、さらには欠陥原因の除去などが製造工程の生産歩留りの側面から重要な部分であるのに違いない。   On the other hand, image display devices can undergo various inspections during the manufacturing process before they are delivered to the market, and thus go through many inspection processes, but the most frequently used components among image display devices. One of them is various optical films such as a polarizing film and a retardation film. Therefore, defects in the optical film are one of the main causes of defects in the image display device. To detect a defect in an optical film, first determine whether it is a defect and perform an accurate determination. Then, if it is determined as a defect, repair or discard the defect, and remove the cause of the defect. This must be an important part of the production process from the aspect of production yield.

光学フィルムの製造において、産業における大量生産のためには通常ライン工程を用いる。従って、欠陥の検出は、ラインの特定位置で光学フィルムを連続的に撮影し、撮影された部分で欠陥を判別することによって行われる。   In the production of optical films, a line process is usually used for mass production in industry. Therefore, the defect is detected by continuously photographing the optical film at a specific position on the line and determining the defect at the photographed portion.

欠陥判別に関しては、従来、多様な欠陥を確実に検出することが重要であった。これに関して、韓国公開特許第２０１０−２４７５３号は、異物を含む閉曲線と異物の面積とを比べてライン状の異物を判別する方法を開示している。   Conventionally, it has been important to detect various defects reliably for defect determination. In this regard, Korean Patent No. 2010-24753 discloses a method for discriminating a line-shaped foreign object by comparing a closed curve including the foreign object and the area of the foreign object.

しかしながら、最近、光学フィルムも大型化の傾向に伴って部品のコストが上昇することにつれ、より正確な欠陥判別方法が求められており、それ故に、依然として欠陥を正確に判別することができる方法が求められている。   However, recently, as the cost of parts increases with the trend of increasing the size of optical films, more accurate defect determination methods are required, and therefore there is still a method that can accurately determine defects. It has been demanded.

韓国公開特許第２０１０−２４７５３号Korean Open Patent 2010-24753

本発明は、光学フィルムの欠陥及び非欠陥を正確に判別する方法を提供することを目的とする。   It is an object of the present invention to provide a method for accurately discriminating between defects and non-defects in an optical film.

本発明は、本来欠陥ではないが、従来、欠陥と判別されていたものを欠陥ではないものとして判別する光学フィルムの欠陥判別方法を提供することを目的とする。   An object of the present invention is to provide a method for discriminating defects of an optical film that discriminates what has conventionally been discriminated as a defect, although it is not a defect in nature.

１．（Ｓ１）移送される光学フィルムを撮影して異物が存在する領域を選別する段階と、
（Ｓ２）前記領域中の異物のうち、移送方向に平行な二辺と、それに垂直な二辺とからなる長方形が最小面積で異物を含む場合に、前記移送方向に平行な辺がそれに垂直な辺より大きい場合、線状良品性異物と判定して欠陥から除外する段階と
を備える、光学フィルムの欠陥判別方法。 1. (S1) A step of photographing an optical film to be transferred and selecting a region where foreign matters exist;
(S2) Among the foreign substances in the region, when a rectangle composed of two sides parallel to the transfer direction and two sides perpendicular to the foreign object contains the minimum area, the side parallel to the transfer direction is perpendicular to the rectangle. A method for determining a defect in an optical film, comprising: determining that the foreign object is a linear non-defective foreign substance and excluding the defect from the defect.

２．前記項目１において、前記長方形の長辺の長さが５ピクセル以上であり、短辺の長さが長辺の０．８倍以下の異物である場合、線状良品性異物と判定する、光学フィルムの欠陥判別方法。   2. In item 1, when the length of the long side of the rectangle is 5 pixels or more and the length of the short side is 0.8 times or less of the long side, it is determined as a linear non-defective foreign material. Film defect discrimination method.

３．前記項目１において、前記線状良品性異物と判定されていない異物のうち、異物を含む最小面積の長方形の長辺の長さが３０ピクセル以下であり、下記数式１による欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル以下である場合、直線状良品性異物と判定して欠陥から除外する段階をさらに含む、光学フィルムの欠陥判別方法。   3. In the item 1, among the foreign matters that are not determined to be the linear non-defective foreign matter, the length of the long side of the rectangle with the smallest area including the foreign matter is 30 pixels or less, and the defect density according to the following formula 1 is 40% or less. And when the shortened length of the centerline image of the foreign matter is 3 pixels or less, the method further comprises a step of determining that the foreign matter is a straight non-defective foreign matter and excluding it from the defect.

４．前記項目３において、前記異物の長辺の長さが３０ピクセル超過であれば大型欠陥と判定する、光学フィルムの欠陥判別方法。   4). In the item 3, the defect discriminating method for an optical film, wherein the defect is determined to be a large defect if the length of the long side of the foreign matter exceeds 30 pixels.

５．前記項目３において、前記異物の長辺の長さが３０ピクセル以下であり、前記数式1による欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル超過であれば曲線状欠陥と判定する、光学フィルムの欠陥判別方法。   5. In item 3, if the length of the long side of the foreign object is 30 pixels or less, the defect density according to Equation 1 is 40% or less, and the shortened length of the center line image of the foreign object exceeds 3 pixels An optical film defect determination method for determining a curved defect.

６．前記項目３において、長辺の長さが３０ピクセル以下であり、数式１の欠陥密度が４０％超過である異物に対して欠陥密度が７５％以下の異物は、斜方状良品性異物と判定して欠陥から除外する段階をさらに含む、光学フィルムの欠陥判別方法。   6). In the item 3, a foreign object having a defect density of 75% or less with respect to a foreign object having a long side length of 30 pixels or less and having a defect density exceeding 40% in Formula 1 is determined to be a rhombic non-defective product. And a method for discriminating defects in an optical film, further comprising the step of excluding the defects from the defects.

７．前記項目６において、欠陥密度が７５％超過である異物のうち前記円の内部位置による明度グラフがその勾配値がプラスからマイナスに転じる箇所が２以上存在する異物は、エンボス状良品性異物と判定して欠陥から除外する段階をさらに含む、光学フィルムの欠陥判別方法。   7). In the above item 6, among foreign matters having a defect density exceeding 75%, a foreign matter having two or more portions where the gradient value of the lightness graph by the internal position of the circle changes from positive to negative is determined as an embossed non-defective foreign matter. And a method for discriminating defects in an optical film, further comprising the step of excluding the defects from the defects.

８．前記項目７において、前記グラフの勾配値がプラスからマイナスに転じる箇所が３以上存在する異物は、エンボス状良品性異物と判定する、光学フィルムの欠陥判別方法。   8). In the item 7, a defect determination method for an optical film, wherein a foreign matter having three or more locations where the gradient value of the graph changes from positive to negative is determined as an embossed non-defective foreign matter.

９．前記項目１乃至８のうちいずれか一項において、前記領域中の異物はクラスター欠陥ではない異物であって、前記クラスター欠陥はいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合である、光学フィルムの欠陥判別方法。   9. In any one of the items 1 to 8, the foreign matter in the region is a foreign matter that is not a cluster defect, and the cluster defect is a foreign matter that is different in a circle having a radius of 5 mm around the single foreign matter. A method for discriminating defects in an optical film, which is a collection of the foreign matters including a central foreign matter when two or more exist.

１０．前記項目１乃至８のうちいずれか一項において、前記領域中の異物は微細欠陥ではない異物であって、前記微細欠陥は８ピクセル×８ピクセルの正四角形の内部に含まれる異物である、光学フィルムの欠陥判別方法。   10. 9. The optical device according to any one of items 1 to 8, wherein the foreign matter in the region is a foreign matter that is not a fine defect, and the fine defect is a foreign matter contained in a regular square of 8 pixels × 8 pixels. Film defect discrimination method.

１１．前記項目１乃至８うちいずれか一項において、前記領域中の異物はクラスター欠陥及び微細欠陥ではない異物であって、前記クラスター欠陥はいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合であり、前記微細欠陥は８ピクセル×８ピクセルの正四角形の内部に含まれる異物である、光学フィルムの欠陥判別方法。   11. In any one of the above items 1 to 8, the foreign matter in the region is a foreign matter that is not a cluster defect or a fine defect, and the cluster defect is different within a circle having a radius of 5 mm around the single foreign matter. An optical film defect discriminating method, wherein when two or more foreign substances are present, it is a set of the foreign substances including a central foreign substance, and the fine defect is a foreign substance contained in a regular square of 8 pixels × 8 pixels.

１２．（Ｓ１）移送される光学フィルムを撮影して異物が存在する領域を選別する段階と、
(Ｓ１-Ａ）前記領域中の異物のうちいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合をクラスター欠陥と判別する段階と、
（Ｓ１-Ｂ）前記クラスター欠陥と判別されていない異物のうち８ピクセル×８ピクセルの正四角形の内部に含まれる異物は微細欠陥と判別する段階と、
（Ｓ２）前記微細欠陥と判別されていない異物のうち、異物を含む最小面積の長方形が移送方向に平行な二辺とそれに垂直な二辺とからなり、前記移送方向に平行な辺がそれに垂直した辺より大きい場合、線状良品性異物と判定して欠陥から除外する段階と
を備える、光学フィルムの欠陥判別方法。 12 (S1) A step of photographing an optical film to be transferred and selecting a region where foreign matters exist;
(S1-A) When two or more different foreign objects exist in a circle having a radius of 5 mm centering on any one of the foreign substances in the region, the set of the foreign substances including the central foreign substance is determined as a cluster defect. When,
(S1-B) a step of discriminating foreign matter contained in a regular square of 8 pixels × 8 pixels among the foreign matters not discriminated as cluster defects as fine defects;
(S2) Among the foreign matters not identified as the fine defects, a rectangle having the smallest area including the foreign matters is composed of two sides parallel to the transfer direction and two sides perpendicular thereto, and the side parallel to the transfer direction is perpendicular to the two sides. A method for discriminating defects in an optical film, comprising: determining that the foreign object is a linear non-defective foreign substance and excluding it from the defect.

１３．前記項目１２において、（Ｓ２）段階の長方形の長辺の長さが５ピクセル以上であり、短辺の長さが長辺の０．８倍以下の異物である場合、線状良品性異物と判定する、光学フィルムの欠陥判別方法。   13. In the item 12, in the case where the long side length of the rectangle in the step (S2) is 5 pixels or more and the short side length is 0.8 times or less of the long side, An optical film defect determination method for determining.

１４．前記項目１２において、前記線状良品性異物と判定されていない異物のうちその長辺の長さが３０ピクセル以下であり、下記数式１の欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル以下である場合、直線状良品性異物と判定して欠陥から除外する段階を備える、光学フィルムの欠陥判別方法。   14 In the item 12, among the foreign matters not determined as the linear good quality foreign matter, the length of the long side is 30 pixels or less, the defect density of the following formula 1 is 40% or less, and the center line of the foreign matter A method for discriminating defects in an optical film, comprising a step of determining a straight non-defective foreign substance and excluding it from a defect when the shortened length of an image is 3 pixels or less.

１５．前記項目１４において、前記異物の長辺の長さが３０ピクセル超過であれば大型欠陥と判定する、光学フィルムの欠陥判別方法。   15. Item 14. The optical film defect determination method according to Item 14, wherein if the length of the long side of the foreign material exceeds 30 pixels, it is determined as a large defect.

１６．前記項目１４において、前記異物の長辺の長さが３０ピクセル以下であり、前記数式１による欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル超過であれば曲線状欠陥と判定する、光学フィルムの欠陥判別方法。   16. In item 14, if the length of the long side of the foreign object is 30 pixels or less, the defect density according to Equation 1 is 40% or less, and the shortened length of the center line image of the foreign object exceeds 3 pixels An optical film defect determination method for determining a curved defect.

１７．前記項目１４において、長辺の長さが３０ピクセル以下であり、数式１の欠陥密度が４０％超過である異物に対して欠陥密度が７５％以下の異物は、斜方状良品性異物と判定して欠陥から除外する段階をさらに含む、光学フィルムの欠陥判別方法。   17. In the item 14, foreign matters having a defect density of 75% or less with respect to foreign matters having a long side length of 30 pixels or less and a defect density of Equation 1 exceeding 40% are determined to be rhombic non-defective foreign matters. And a method for discriminating defects in an optical film, further comprising the step of excluding the defects from the defects.

１８．前記項目１７において、欠陥密度が７５％超過である異物のうち前記円の内部位置による明度グラフが、その勾配値がプラスからマイナスに転じる箇所が２以上存在する異物は、エンボス状良品性異物と判定して欠陥から除外する段階をさらに含む、光学フィルムの欠陥判別方法。 18. In the item 17, among the foreign matters having a defect density exceeding 75%, the lightness graph based on the internal position of the circle has two or more places where the gradient value changes from positive to negative. A method for discriminating defects in an optical film, further comprising a step of determining and excluding the defects from the defects.

１９．前記項目１８において、前記箇所でグラフの勾配値がプラスからマイナスに転じる箇所が３以上存在する異物はエンボス状良品性異物と判定する、光学フィルムの欠陥判別方法。   19. 18. The optical film defect determination method according to item 18, wherein the foreign matter having three or more locations where the gradient value of the graph changes from positive to negative at the location is determined as an embossed non-defective foreign matter.

本発明の光学フィルムの欠陥判別方法は、実際は欠陥ではないが、従来、欠陥と判別されていたものなどを正確に判定することによって、光学フィルムの製造歩留りを顕著に上昇させることができる。   The optical film defect determination method of the present invention is not actually a defect, but can accurately increase the production yield of the optical film by accurately determining what has conventionally been determined as a defect.

なお、本発明の光学フィルムの欠陥判別方法は、製造コストを大幅に減少させることができ、資源のロスも防止することができる。   In addition, the optical film defect determination method of the present invention can greatly reduce the manufacturing cost, and can prevent the loss of resources.

本発明の一実施形態として線状良品性異物を判別する方法の概略的なフローチャートである。It is a schematic flowchart of the method of discriminating a linear good quality foreign material as one Embodiment of this invention. ４種の線状良品性異物の撮影写真である。It is a photography photograph of four kinds of linear good quality foreign substances. 線状良品性異物の一例を概略的に示す図である。It is a figure which shows roughly an example of a linear good quality foreign material. 本発明の他の実施形態として線状良品性異物、大型欠陥、直線状良品性異物及び曲線状欠陥を判別する方法の概略的なフローチャートである。It is a schematic flowchart of the method of discriminating a linear good quality foreign material, a large defect, a linear good quality foreign material, and a curved defect as other embodiment of this invention. 直線状欠陥の一例を概略的に示す図である。It is a figure which shows an example of a linear defect roughly. 本発明の他の実施形態として線状良品性異物、大型欠陥、直線状良品性異物、曲線状欠陥及び斜方状良品性異物を判別する方法の概略的なフローチャートである。6 is a schematic flowchart of a method for discriminating linear non-defective foreign matters, large defects, linear non-defective foreign matters, curved defects and orthorhombic non-defective foreign matters as another embodiment of the present invention. 斜方状良品性異物の撮影写真である。It is a photography photograph of a rhombic good quality foreign material. 本発明の他の実施形態として線状良品性異物、大型欠陥、直線状良品性異物、曲線状欠陥、斜方状良品性異物、点状欠陥、及びエンボス状良品性異物を判別する方法の概略的なフローチャートである。Outline of a method for discriminating linear non-defective foreign matters, large defects, linear non-defective foreign matters, curved defects, orthorhombic non-defective foreign matters, point defects, and embossed non-defective foreign matters as other embodiments of the present invention It is a typical flowchart. エンボス状良品性異物の多様な類形の映像写真（ａ）、及びエンボス状良品性異物が発生した場合、離型フィルム内部に存在する欠陥を有する離型フィルムの断面ＳＥＭ写真（ｂ）である。It is a cross-sectional SEM photograph (b) of the release film which has the defect which exists in a release film, when the image | photograph (a) of various types of embossed good quality foreign material and the embossed good quality foreign material generate | occur | produced. . エンボス状良品性異物の一例（ａ、ｂ）及び明度グラフ（ｃ）を示す図である。It is a figure which shows an example (a, b) and brightness graph (c) of an embossed non-defective item. クラスター欠陥の一例を概略的に示す図である。It is a figure which shows an example of a cluster defect roughly. 本発明の他の実施形態としてクラスター欠陥、微細欠陥、線状良品性異物、大型欠陥、直線状良品性異物、曲線状欠陥、斜方状良品性異物、点状欠陥、及びエンボス状良品性異物を判別する方法の概略的なフローチャートである。As other embodiments of the present invention, cluster defect, fine defect, linear good quality foreign material, large defect, linear good quality foreign material, curved defect, orthorhombic good quality foreign material, point defect, and embossed good quality foreign material It is a schematic flowchart of the method to discriminate | determine.

本発明は、（Ｓ１）移送される光学フィルムを撮影して異物が存在する領域を選別する段階と、（Ｓ２）前記領域中の異物のうち、移送方向に平行な二辺とそれに垂直な二辺とからなる長方形が最小面積で異物を含む場合に、前記移送方向に平行な辺がそれに垂直な辺より大きい場合、線状良品性異物と判定して欠陥から除外する段階とを備えることによって、光学フィルムの製造歩留りを顕著に上昇させ、製造コストを大幅に減少させることができる。   The present invention includes (S1) a step of photographing an optical film to be transported to select a region where foreign matter is present, and (S2) among the foreign matter in the region, two sides parallel to the transport direction and two perpendicular thereto. When a rectangle composed of a side includes a foreign substance with a minimum area, and a side parallel to the transfer direction is larger than a side perpendicular to the transfer direction, the linear non-defective foreign matter is determined and excluded from the defect. The production yield of the optical film can be significantly increased, and the production cost can be greatly reduced.

以下では、図を参照して本発明に関してさらに詳細に説明する。   Hereinafter, the present invention will be described in more detail with reference to the drawings.

図１は、本発明の一実施形態に係る光学フィルムの欠陥判別方法のフローチャートを概略的に示す図である。   FIG. 1 is a diagram schematically showing a flowchart of an optical film defect determination method according to an embodiment of the present invention.

先ず、移送される光学フィルムを撮影して異物が存在する領域を選別する（Ｓ１）。   First, a region where foreign matter exists is selected by photographing the transferred optical film (S1).

通常光学フィルムの製造は、連続工程、例えばロール・ツ・ーロール（Ｒｏｌｌ−ｔｏ−Ｒｏｌｌ）工程を通じて移送されて行われる。従って、光学フィルムの欠陥を判別するためには、一定方向に移送される光学フィルムの上部で光学フィルムを撮影し、光学フィルムの画像を取得する。取得された画像において異物の存在する領域があれば、これを選別して欠陥であるか否かを判別する工程を開始する。   In general, the optical film is manufactured by being transferred through a continuous process, for example, a roll-to-roll process. Therefore, in order to determine the defect of the optical film, the optical film is photographed on the upper part of the optical film transferred in a certain direction, and an image of the optical film is acquired. If there is a region where foreign matter exists in the acquired image, a step of selecting this and determining whether or not it is a defect is started.

本実施形態では、光学フィルムとして偏光フィルムを用い、検査映像は検査対象試料の偏光フィルムの偏光方向に垂直である他の偏光フィルムを検査対象フィルムの上部に位置させた後、試料の下部に光源を位置させて二つの偏光フィルムを通過する光を撮影して得られたものである。検査対象の偏光フィルムが良品であれば偏光方向が互いに垂直である二つの偏光フィルムを通過する光がなくなるため、黒色の映像が得られるが、検査対象の偏光フィルムに異物が存在するとその部分で偏光の方向が変わるので、その結果、光漏れが生じて明るい部分（すなわち、異物部分）が存在する映像が得られる。   In the present embodiment, a polarizing film is used as the optical film, and the inspection image is positioned on the upper part of the inspection target film with another polarizing film perpendicular to the polarization direction of the polarizing film of the inspection target sample, and then a light source is provided below the sample. Is obtained by photographing the light passing through the two polarizing films. If the polarizing film to be inspected is a non-defective product, there will be no light passing through the two polarizing films whose polarization directions are perpendicular to each other, so a black image can be obtained. Since the direction of polarization changes, as a result, light leakage occurs and an image having a bright part (that is, a foreign substance part) is obtained.

本発明において、「異物」とは、光学フィルムの平均的な均一性から逸脱する部分であって、判別結果によって正常範囲内であるものと判定されるか(良品性異物）、或いは製品の不良の原因である「欠陥」であるものと判定され得る部分である。   In the present invention, the term “foreign matter” is a portion that deviates from the average uniformity of the optical film, and is determined to be within the normal range according to the discrimination result (non-defective foreign matter) or defective product. This is a portion that can be determined to be a “defect” that is the cause of the problem.

取得された画像から異物が存在する領域を選別することは、光学フィルムの平均的な均一性を設定した後、これを逸脱する部分（異物部分）を含む領域の画像を画像処理ソフトウェアなどを用いて遂行することができる。   Sorting the area where foreign matter exists from the acquired image is to set the average uniformity of the optical film, and then use the image processing software etc. for the image of the area that includes the part (foreign matter part) that deviates from this Can be carried out.

次いで、前記領域中の異物のうち、移送方向に平行な二辺とそれに垂直な二辺とからなる長方形が最小面積で異物を含む場合に、移送方向に平行な２辺がそれに垂直な辺より大きい場合、線状良品性異物と判定して欠陥から除外する（Ｓ２）。   Next, among the foreign substances in the region, when a rectangle composed of two sides parallel to the transfer direction and two sides perpendicular thereto includes the minimum area, the two sides parallel to the transfer direction are If larger, it is determined as a linear non-defective foreign material and excluded from the defect (S2).

光学フィルムの産業における製造の場合、光学フィルムの保管及び移送の便宜のために光学フィルムの両側面に離型フィルムなどを設けて製造するようになるが、欠陥判別過程では、離型フィルムが貼り付けられた状態の光学フィルムを検査するようになるので、光学フィルムの異物のみならず、離形フィルムの損傷、離形フィルム内部の異物又は光学フィルムと離形フィルムとの間の異物も検出するようになる。しかしながら、離形フィルムの損傷やその内部の異物又は光学フィルムと離形フィルムとの間の異物は、光学フィルムが画像表示装置に取り入れられる場合には、離形フィルムと共に除去されるため、実際の欠陥ではない。しかしながら、従来にはこのような離型フィルムにおける欠陥を別途に判別し得る方法が紹介されたことがないため、良品を不良品と誤判別する場合が多かった。このような問題は、それによって製造コストの上昇の原因となり得、とりわけ最近の画像表示装置の大型化の傾向によって光学フィルムも大型化している状況において、このような問題点はさらに深刻になり得る。それ故に、本発明は、離型フィルムにおける欠陥である線状良品性異物を判別することによって、このような問題点が解決される。特に、光学フィルムが製造工程に沿って移送される場合に、移送方向に平行な方向に長い形態を有する損傷が離形フィルムに発生する場合が多い。このような損傷は、離形フィルムの損傷であり、光学フィルムそのものの損傷ではないため、本発明は、このような離型フィルムの損傷を線状良品性異物と判定して、光学フィルムの欠陥から除外することをその特徴とする。図２には、このような線状良品性異物の例の撮影映像画像写真を示している。図２に示した映像写真は、上下方向が移送方向である光学フィルムに対して撮影したものである。   In the case of manufacturing optical films in the industry, release films are provided on both sides of the optical film for the convenience of storage and transportation of the optical film. Since the attached optical film is inspected, it detects not only foreign matter on the optical film but also damage to the release film, foreign matter inside the release film, or foreign matter between the optical film and the release film. It becomes like this. However, the damage to the release film and the foreign matter inside it or the foreign matter between the optical film and the release film are removed together with the release film when the optical film is incorporated into the image display device. Not a defect. However, since no method has been introduced that can separately determine such defects in the release film, non-defective products are often erroneously determined as defective products. Such a problem can thereby cause an increase in manufacturing cost. In particular, in a situation where the optical film is also enlarged due to the recent trend of increasing the size of the image display device, such a problem can be further serious. . Therefore, according to the present invention, such a problem is solved by discriminating a linear non-defective foreign material which is a defect in the release film. In particular, when the optical film is transferred along the manufacturing process, damage having a long shape in a direction parallel to the transfer direction often occurs in the release film. Since such damage is damage to the release film and not to the optical film itself, the present invention determines that such damage to the release film is a linear non-defective foreign matter, and causes defects in the optical film. It is characterized by excluding from the above. FIG. 2 shows a photographed video image of an example of such a linear non-defective foreign material. The video photograph shown in FIG. 2 was taken with respect to an optical film whose vertical direction is the transport direction.

図３は、線状良品性異物１１０の判別方法の一具現例を概略的に示す。本発明は、移送方向に平行な二辺とそれに垂直な二辺とからなる長方形が最小面積で異物を含む場合に、前記移送方向に平行な辺の長さがそれに垂直な辺の長さより大きい場合には、これを実際の欠陥ではない線状良品性異物１１０と判定して欠陥から除外することを特徴とする。好ましくは、前記長方形の長辺（ｙ）の長さが５ピクセル以上であり、短辺（ｘ）の長さが長辺の０．８倍以下であり得る。ピクセルとは、予め定められた解像度の画像での最も基本的な単位画素を意味する。前記長辺の長さが５ピクセル未満であるか、或いは前記短辺の長さが長辺の０．８倍超過である場合には、異物が実際の欠陥となり得る。   FIG. 3 schematically illustrates an example of a method for determining the linear non-defective foreign material 110. In the present invention, when a rectangle composed of two sides parallel to the transfer direction and two sides perpendicular to it includes a foreign substance with a minimum area, the length of the side parallel to the transfer direction is larger than the length of the side perpendicular to it. In this case, this is characterized in that it is determined as a linear non-defective foreign material 110 that is not an actual defect and is excluded from the defect. Preferably, the length of the long side (y) of the rectangle is 5 pixels or more, and the length of the short side (x) may be 0.8 times or less of the long side. A pixel means the most basic unit pixel in an image with a predetermined resolution. If the length of the long side is less than 5 pixels, or if the length of the short side is more than 0.8 times the long side, the foreign matter can become an actual defect.

さらに、必要に応じて、本発明の他の実施形態において、前記線状良品性異物と判定されていない異物のうち異物を含む最小面積の長方形の長辺の長さが３０ピクセル以下であり、下記数式１による欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル以下である場合には、直線状良品性異物と判定して欠陥から除外する段階をさらに含むことができる。   Furthermore, if necessary, in another embodiment of the present invention, the length of the long side of the minimum area of the rectangle including the foreign matter among the foreign matters not determined to be the linear non-defective foreign matter is 30 pixels or less, When the defect density according to the following Equation 1 is 40% or less and the shortened length of the center line image of the foreign material is 3 pixels or less, the method further includes a step of determining that the defect is a linear non-defective foreign material and excluding it from the defect. be able to.

好ましくは、前記欠陥密度が３０％以下であり、前記中心線短縮長さが２ピクセル以下である場合に直線状良品性異物と判定することができる。   Preferably, when the defect density is 30% or less and the center line shortening length is 2 pixels or less, it can be determined as a non-defective product having a linear shape.

図４には、直線状良品性異物を判定する概略的なフローチャートを示す。直線状良品性異物の判定段階は、前述した線状良品性異物の判定段階で前記移送方向に平行な辺の長さが、それと垂直な辺の長さと同一又は小さい場合に該当し、線状良品性異物に属しない異物に対して遂行されるさらなる欠陥判定段階である。前述した線状良品性異物は、移送方向に長い形態の異物に限定されたが、実際には、特定方向に関わらず、ある一方向に長い形態の異物は、実質的に離型フィルムに形成された損傷である場合が殆どである。これによって、本発明では、特定方向に関わらず、ある一方向に長い形態の良品性異物を判別する方法をさらに提供することによって、実際の良品をより正確に区別することができ、それによって良品が不良品と誤判別する場合をさらに減少させることができる。   FIG. 4 shows a schematic flowchart for determining a linear non-defective foreign material. The determination step of the linear non-defective foreign matter corresponds to the case where the length of the side parallel to the transfer direction is equal to or smaller than the length of the side perpendicular to the transfer direction in the determination step of the linear non-defective foreign matter. This is a further defect determination step performed for foreign matters that do not belong to non-defective foreign matters. The above-mentioned linear non-defective foreign matters are limited to foreign matters that are long in the transfer direction, but in reality, foreign matters that are long in one direction are substantially formed on the release film regardless of the specific direction. In most cases, the damage has been made. Accordingly, in the present invention, an actual non-defective product can be more accurately distinguished by further providing a method for discriminating non-defective foreign matters having a long shape in one direction regardless of a specific direction. Can be further reduced when the product is misidentified as a defective product.

具体的には、先ず図４を参照すると、直線状良品性異物の判定段階において、異物を含む最小面積の長方形の長辺の長さが３０ピクセル以下である。３０ピクセルを超過するようになると、これは実際の光学フィルムの欠陥と判定することができる(以下、「大型欠陥」と称す）。   Specifically, referring first to FIG. 4, the length of the long side of the rectangle with the smallest area including foreign matter is 30 pixels or less in the step of determining a linear non-defective foreign matter. If it exceeds 30 pixels, this can be determined as an actual optical film defect (hereinafter referred to as a “large defect”).

また、図５には直線状良品性異物２１０の判別方法における、異物の中心線を含む短縮を利用する一具現例を概略的に示す。図５の（ａ）は異物２１０の映像であり、（ｂ）は異物２１０の中心線２２０の映像である。異物の中心線映像は、当分野に知られている方法で得ることができ、例えばＴｈｉｎｎｉｎｇ、Ｓｋｅｌｅｔｏｎなどの映像処理方法を用いることができるが、これらに限定されるものではない。図５の(c）は中心線の短縮２２１を示している。中心線の短縮とは、中心線を成すピクセルにおける任意の二つのピクセル間の距離のうち最も長い距離を成す線を長軸とし、前記長軸から他のピクセル箇所の間の垂直距離のうち最も長いものを短縮と称する。図５の中心線短縮２２１は、他の矢印である長軸と垂直関係である。本発明による直線状良品性異物は、中心線の短縮２２１の長さが３ピクセル以下である。３ピクセルを超過するようになると、これは実際の光学フィルムの欠陥と判定することができる(以下、「曲線状欠陥」と称す）。   FIG. 5 schematically shows an implementation example using the shortening including the center line of the foreign material in the method for determining the linear non-defective foreign material 210. 5A is an image of the foreign object 210, and FIG. 5B is an image of the center line 220 of the foreign object 210. The center line image of the foreign material can be obtained by a method known in the art, and for example, an image processing method such as Thinning or Skeleton can be used, but is not limited thereto. FIG. 5C shows the shortening 221 of the center line. The shortening of the center line refers to the longest line among the distances between any two pixels in the pixels forming the center line, and the longest vertical distance from the major axis to the other pixel locations. The long one is called shortening. The center line shortening 221 in FIG. 5 is perpendicular to the major axis, which is another arrow. In the linear non-defective foreign material according to the present invention, the length of the center line shortening 221 is 3 pixels or less. If it exceeds 3 pixels, it can be determined as an actual optical film defect (hereinafter referred to as a “curved defect”).

また、前記欠陥密度が４０％超過である場合にも異物が実際の欠陥となり得る。   Further, even when the defect density exceeds 40%, the foreign matter can become an actual defect.

さらに、必要に応じて、本発明のまた他の実施形態において、前記数式１の欠陥密度が４０％超過である異物に対して欠陥密度が７５％以下の異物は、斜方状良品性異物と判定して欠陥から除外する段階をさらに含むことができる。   Furthermore, as required, in another embodiment of the present invention, a foreign matter having a defect density of 75% or less with respect to a foreign matter having a defect density of more than 40% in Formula 1 may be a rhombic non-defective foreign matter. The method may further include determining and excluding from defects.

図６には、斜方状良品性異物を判定する概略的なフローチャートを示し、図７には、欠陥密度が５８％である斜方状良品性異物の撮影映像写真を示す。図７の（ａ）は斜方状良品性異物の画像であり、（ｂ）は斜方状良品性異物の形態をより分かりやすくする図形を付け加えた画像である。   FIG. 6 shows a schematic flow chart for determining an orthorhombic non-defective foreign material, and FIG. 7 shows a photographed video image of the rhombic foreign material having a defect density of 58%. FIG. 7A is an image of the orthorhombic non-defective foreign matter, and FIG. 7B is an image to which a figure that makes the form of the orthorhombic non-defective foreign matter easier to understand is added.

斜方状良品性異物の判定段階は、前述した直線状良品性異物の判定段階で長辺の長さが３０ピクセル以下であるが、前記欠陥密度が４０％超過である場合に該当し、直線状良品性異物に属しない異物に対して遂行される、さらなる欠陥判定段階であって、このような斜方状良品性異物も離型フィルムに係わる欠陥としてこれをさらに区別することによって良品を不良品と誤判別する場合をさらに減少させることができる。斜方状良品性異物の判定段階では、直線状良品性異物の判定段階の中心線短縮に対する判定基準は用いられなくても関係ない。欠陥密度が７５％超過である場合には、異物が実際の欠陥となり得る。   The determination step of the orthorhombic non-defective foreign matter corresponds to the case where the length of the long side is 30 pixels or less in the above-described determination step of the non-uniform linear non-defective foreign matter, but the defect density exceeds 40%, and the straight line This is a further defect determination step that is performed for foreign matters that do not belong to the good quality foreign matter. Such a good quality foreign matter is also identified as a defect related to the release film, so that the non-defective product is rejected. The number of cases where the product is erroneously determined as a non-defective product can be further reduced. It does not matter whether the criterion for shortening the center line in the determination step of the straight non-defective foreign matter is not used in the determination step of the oblique non-defective foreign matter. If the defect density exceeds 75%, the foreign matter can become an actual defect.

さらに、必要に応じて、本発明のさらに他の実施形態において、前記欠陥密度が７５％超過である異物のうち前記円の内部位置による明度グラフがその勾配値がプラスからマイナスに転じる箇所が２以上存在する異物はエンボス状良品性異物と判定して欠陥から除外する段階をさらに含むことができる。好ましくは、明度グラフの勾配値がプラスからマイナスに転じる箇所が３以上存在する異物をエンボス状良品性異物と判定することができる。   Furthermore, if necessary, in still another embodiment of the present invention, among the foreign matters having the defect density exceeding 75%, there are two locations where the lightness graph according to the internal position of the circle changes its slope value from positive to negative. The foreign matter present above may further include a step of determining it as an embossed non-defective foreign matter and excluding it from the defect. Preferably, a foreign matter having three or more locations where the gradient value of the brightness graph changes from positive to negative can be determined as an embossed non-defective foreign matter.

図８には、エンボス状良品性異物を判定する概略的なフローチャートが示されており、エンボス状良品性異物の判定段階は、前述した斜方状良品性異物の判定段階で前記欠陥密度が７５％超過である場合に該当し、斜方状良品性異物に属しない異物に対して遂行される、さらなる欠陥判定段階である。このようなエンボス状良品性異物は、離型フィルムの内部に異物が存在して発生する場合が殆どである。   FIG. 8 shows a schematic flowchart for determining the embossed non-defective foreign matter, and the step of determining the embossed non-defective foreign matter is the aforementioned step of determining the oblique non-defective foreign matter, and the defect density is 75. This is a further defect determination step that is performed for a foreign matter that does not belong to the orthorhombic non-defective foreign matter. Such embossed non-defective foreign matters are mostly generated due to the presence of foreign matters inside the release film.

図９には、エンボス状良品性異物の多様な類形の映像写真（ａ）及びエンボス状良品性異物が発生した場合、離型フィルム内部に存在する欠陥を有する離型フィルムの断面ＳＥＭ写真（ｂ）を示す。   FIG. 9 shows various types of image photographs (a) of embossed non-defective foreign substances, and cross-sectional SEM photographs of release films having defects existing inside the release film when embossed non-defective foreign substances are generated ( b).

故に、エンボス状良品性異物は、離型フィルムの欠陥から発生したものであるため、これをより正確に区別することによって良品が不良品であると誤判別する場合をさらに減少させることができる。 Therefore, since the embossed non-defective foreign matter is generated from a defect in the release film, it is possible to further reduce the case where the non-defective product is erroneously determined to be defective by more accurately distinguishing it.

図１０には、エンボス状良品性異物の一実施形態として異物を含む最小面積の円内部に４個の領域からなる異物３１０と前記領域に対する明度グラフとが示されている。図１０の（ａ）はエンボス状良品性異物の画像であり、（ｂ）はエンボス状良品性異物の形態をより分かりやすく線図形を付記した画像である。   FIG. 10 shows, as an embodiment of the embossed non-defective foreign material, a foreign material 310 consisting of four regions inside a circle with a minimum area including the foreign material, and a brightness graph for the region. (A) of FIG. 10 is an image of the embossed non-defective foreign material, and (b) is an image in which the shape of the embossed non-defective foreign material is more easily understood.

エンボス状良品性異物であるか否かを判断するためには、異物内部の明度を測定したグラフを参照する。明度グラフは、正常領域に比べて異物領域を明るく表示した映像画像から算出する。明度グラフとして、通常使用可能なグラフはグレーレベル(ｇｒｅｙ ｌｅｖｅｌ）グラフであって、グレーレベルは黒（０）から白（２５５）までを０〜２５５段階に分けてその明暗の程度を判断する基準である。   In order to determine whether or not it is an embossed non-defective foreign material, a graph measuring the brightness inside the foreign material is referred to. The brightness graph is calculated from a video image in which the foreign substance area is displayed brighter than the normal area. As a lightness graph, a graph that can be normally used is a gray level graph, and the gray level is a standard for judging the degree of lightness by dividing black (0) to white (255) into 0 to 255 levels. It is.

図１０を参照すると、異物３１０内部の明度変化を正確に判断するために、明度変化が最大の箇所が示される円内部の位置座標軸を定める（Ａ-Ａ’）。定められた座標軸によって異物３１０内部の明度(グレーレベル）を測定してグラフを作成する場合に、勾配値がプラス（＋）からマイナス（−）に転じる部分(上向きの山）が２以上存在すると、エンボス状良品性異物と判断することができる。好ましくは、明度グラフにおいて、明度の閾値（ｐ）を設定して明度の閾値以上の明度値を有するグラフ領域で勾配値がプラス（＋）からマイナス（−）に転じる部分が２以上存在する場合をエンボス状良品性異物と判断することができる。明度の閾値（ｐ）は、勾配がプラスからマイナスに転じる各山のうち最も低い山の最大明度値と、勾配がマイナスからプラスに転じる各谷のうち最も高い谷の最小明度値との間にある値であるものと定義することができ、好ましくは勾配がプラスからマイナスに転じる各山のうち最も低い山の最大明度値と、勾配がマイナスからプラスに転じる各谷のうち最も高い谷の最小明度値との間の平均値とすることができる。   Referring to FIG. 10, in order to accurately determine the brightness change inside the foreign object 310, the position coordinate axis inside the circle where the brightness change is maximum is defined (A-A '). When creating a graph by measuring the brightness (gray level) inside the foreign object 310 using a predetermined coordinate axis, if there are two or more parts (upward peaks) where the slope value changes from plus (+) to minus (-) It can be judged as an embossed non-defective foreign material. Preferably, in the lightness graph, when a lightness threshold value (p) is set and a graph region having a lightness value equal to or higher than the lightness threshold value has two or more portions where the gradient value changes from plus (+) to minus (−) Can be determined as an embossed non-defective foreign material. The lightness threshold (p) is between the maximum lightness value of the lowest mountain among the peaks whose slope changes from positive to negative and the minimum lightness value of the highest valley of each valley where the slope changes from negative to positive. It can be defined as a certain value, preferably the maximum brightness value of the lowest peak of each mountain where the slope changes from positive to negative, and the minimum of the highest valley of each valley where the slope changes from negative to positive It can be an average value between brightness values.

図８を参照すると、エンボス状良品性異物の判定段階において、グラフの勾配値がプラスからマイナスに転じる箇所が１箇所存在するとこれは実際の欠陥となり得る(以下、「点状欠陥」と称す）。   Referring to FIG. 8, if there is one place where the slope value of the graph changes from positive to negative in the determination stage of the embossed non-defective foreign matter, this can be an actual defect (hereinafter referred to as “point defect”). .

本発明の欠陥判別方法は、前述した良品性異物を判別して欠陥から除外する段階を備えることによって製品化し得る良品を不良品と誤判別する場合を顕著に減少することができ、それによって光学フィルムの製造工程において製造コストの顕著な節減効果を得ることができる。   The defect determination method of the present invention can remarkably reduce the case where a non-defective product that can be productized is erroneously determined as a defective product by including the step of determining the above-mentioned non-defective foreign material and excluding it from the defect. In the film manufacturing process, a significant cost saving effect can be obtained.

本発明において必要に応じて、前述した良品性異物の判別段階の迅速性及び信頼性を高めるため、良品性異物の判別段階の前に欠陥を判別する段階を追加して予め遂行することができる。   In the present invention, if necessary, in order to improve the speed and reliability of the above-mentioned non-defective foreign matter determination step, a step of determining a defect can be added in advance before the non-defective foreign matter determination step. .

例えば、本発明の一実施形態において、前記領域中の異物はいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合を欠陥(以下、「クラスター欠陥」と称す）と判断することができ、このようなクラスター欠陥ではない異物に対してのみ良品性異物の判別段階を遂行することができる。前記円は、好ましくは半径が３ｍｍ、より好ましくは半径が１ｍｍであり得る。   For example, in one embodiment of the present invention, if there are two or more different foreign objects in a circle having a radius of 5 mm centering on any one foreign material, the collection of foreign materials including the central foreign material is defective ( Hereinafter, it is referred to as a “cluster defect”), and the non-defective foreign matter discrimination step can be performed only for foreign matters that are not such cluster defects. The circle may preferably have a radius of 3 mm, more preferably a radius of 1 mm.

クラスター欠陥の一実施形態を図１１に示す。図１１を参照すると、異物１、２、３は異物２を中心に予め定められる半径の円内部に存在するようになるため、それぞれ隣接する異物が２個存在するようになり、クラスター欠陥に属するようになる。   One embodiment of a cluster defect is shown in FIG. Referring to FIG. 11, foreign matter 1, 2, and 3 are present inside a circle having a predetermined radius centered on foreign matter 2, so that two adjacent foreign matters exist and belong to cluster defects. It becomes like this.

クラスター欠陥は、不良品となる原因である可能性が非常に高いため、これを先に判別して良品性異物の判別段階の対象として含めないことによって、良品性異物の判別段階の迅速性及び信頼性を高めることができる。   Cluster defects are very likely to be the cause of defective products, so by identifying this first and not including it as a target for the non-defective foreign matter determination step, the speed of the non-defective foreign matter determination step and Reliability can be increased.

例えば、本発明の他の実施形態において、前記領域中の異物が８ピクセル×８ピクセルの正四角形の内部に含まれる場合には、欠陥(以下、「微細欠陥」と称す）と判断することができ、このような微細欠陥ではない異物に対してのみ良品性異物の判別段階を遂行することができる。前記正四角形は、好ましくは５ピクセル×５ピクセル、より好ましくは３ピクセル×３ピクセルであり得る。   For example, in another embodiment of the present invention, when a foreign substance in the region is included inside a regular square of 8 pixels × 8 pixels, it may be determined as a defect (hereinafter referred to as “fine defect”). In other words, the non-defective foreign matter discrimination step can be performed only on foreign matters that are not fine defects. The regular square may be preferably 5 pixels × 5 pixels, more preferably 3 pixels × 3 pixels.

微細欠陥は、不良品となる原因である可能性が非常に高いため、これを先に判別して良品性異物の判別段階の対象として含めないことによって、良品性異物の判別段階の迅速性及び信頼性を高めることができる。   Since it is very likely that a fine defect is a cause of a defective product, by determining this first and not including it as a target of the non-defective foreign matter determination step, the speed of the non-defective foreign matter determination step and Reliability can be increased.

本発明において、クラスター欠陥の判別段階及び微細欠陥の判別段階は、それぞれ単独でのみ遂行することができ、好ましくは各段階を順次に全て遂行することができる。全て遂行する場合には、特に手順の制限なしに遂行することができ、好ましくはクラスター欠陥判別の段階を先に遂行した後、微細欠陥判別の段階を遂行することができる。参考として、図１２には良品性異物を判定する前にクラスター欠陥と微細欠陥を判定する概略的なフローチャートを示す。   In the present invention, the cluster defect discriminating step and the fine defect discriminating step can be carried out independently, and preferably all the steps can be carried out sequentially. When all the processes are performed, the process can be performed without any particular limitation. Preferably, after the cluster defect determination stage is performed first, the fine defect determination stage can be performed. As a reference, FIG. 12 shows a schematic flowchart for determining cluster defects and fine defects before determining non-defective foreign matter.

本発明の不良判別方法は、多様な光学フィルムに適用され得る。このような光学フィルムの例としては、偏光フィルム、位相差フィルムなどを挙げることができるが、これに限定されるものではない。   The defect determination method of the present invention can be applied to various optical films. Examples of such an optical film include a polarizing film and a retardation film, but are not limited thereto.

以上のように、本発明は、限定された実施形態と図面によって説明されたが、本発明はこれによって限定されるものではなく、本発明が属する技術分野における通常の知識を有する者によって本発明の技術思想と下記特許請求の範囲の均等範囲内において多様な修正及び変形が可能なことは言うまでもない。   As described above, the present invention has been described with reference to the limited embodiments and drawings. However, the present invention is not limited thereto, and the present invention is provided by persons having ordinary knowledge in the technical field to which the present invention belongs. It goes without saying that various modifications and variations can be made within the scope of the technical idea and the equivalent scope of the following claims.

Claims (17)

（Ｓ１）移送される光学フィルムを撮影して異物が存在する領域を選別する段階と、
（Ｓ２）前記領域中の異物のうち、移送方向に平行な二辺とそれに垂直な二辺とからなる長方形が最小面積で異物を含む場合に、前記移送方向に平行な辺がそれに垂直な辺より大きい場合、線状良品性異物と判定して欠陥から除外する段階と
を備え、
前記線状良品性異物と判定されていない異物のうち、異物を含む最小面積の長方形の長辺の長さが３０ピクセル以下であり、下記数式１による欠陥密度が４０％以下であり、前記異物の中心線の短縮長さが３ピクセル以下である場合、直線状良品性異物と判定して欠陥から除外する段階をさらに備える、光学フィルムの欠陥判別方法。
(S1) A step of photographing an optical film to be transferred and selecting a region where foreign matters exist;
(S2) Among the foreign matters in the region, when a rectangle composed of two sides parallel to the transfer direction and two sides perpendicular thereto includes the foreign matter with a minimum area, the side parallel to the transfer direction is the side perpendicular to it If it is larger, it is judged as a linear non-defective foreign substance and is excluded from defects ,
Among the foreign matters not determined as the linear non-defective foreign matter, the length of the long side of the rectangle with the smallest area including the foreign matter is 30 pixels or less, the defect density according to the following Equation 1 is 40% or less, and the foreign matter A method for determining a defect in an optical film, further comprising the step of determining a straight non-defective foreign substance and excluding it from the defect when the shortened length of the center line is 3 pixels or less .
前記長方形の長辺の長さが５ピクセル以上であり、短辺の長さが長辺の０．８倍以下の異物である場合、線状良品性異物と判定する、請求項１に記載の光学フィルムの欠陥判別方法。   The length of the long side of the rectangle is 5 pixels or more, and when the length of the short side is 0.8 times or less of the long side, the linear good quality foreign matter is determined. Optical film defect discrimination method. 前記異物の長辺の長さが３０ピクセル超過であれば大型欠陥と判定する、請求項１に記載の光学フィルムの欠陥判別方法。 Determines that large defective if the 30 pixels exceeds the length of the long side of the foreign substance defect discrimination method of an optical film according to claim 1. 前記異物の長辺の長さが３０ピクセル以下であり、前記数式１による欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル超過であれば曲線状欠陥と判定する、請求項１に記載の光学フィルムの欠陥判別方法。 If the length of the long side of the foreign material is 30 pixels or less, the defect density according to Equation 1 is 40% or less, and the shortened length of the center line image of the foreign material exceeds 3 pixels, it is determined as a curved defect. The optical film defect determination method according to claim 1 . 長辺の長さが３０ピクセル以下であり、数式１の欠陥密度が４０％超過である異物に対して欠陥密度が７５％以下の異物は、斜方状良品性異物と判定して欠陥から除外する段階をさらに備える、請求項１に記載の光学フィルムの欠陥判別方法。 Foreign matter having a defect length of 75% or less with respect to a foreign matter having a long side length of 30 pixels or less and the defect density of Equation 1 exceeding 40% is determined to be an oblique non-defective foreign matter and excluded from the defect. further comprising, a defect determination method of an optical film according to claim 1 the step of. 欠陥密度が７５％超過である異物のうち前記円の内部位置による明度グラフがその勾配値がプラスからマイナスに転じる箇所が２以上存在する異物はエンボス状良品性異物と判定して欠陥から除外する段階をさらに含む、請求項５に記載の光学フィルムの欠陥判別方法。 Among foreign matters having a defect density exceeding 75%, a foreign matter having two or more places where the gradient value of the inner circle position changes from positive to negative is determined as an embossed non-defective foreign matter and excluded from the defect. The optical film defect determination method according to claim 5 , further comprising a step. 前記グラフの勾配値がプラスからマイナスに転じる箇所が３以上存在する異物は、エンボス状良品性異物と判定する、請求項６に記載の光学フィルムの欠陥判別方法。 The optical film defect determination method according to claim 6 , wherein a foreign matter having three or more locations where the gradient value of the graph changes from positive to negative is determined as an embossed non-defective foreign matter. 前記領域中の異物はクラスター欠陥ではない異物であって、前記クラスター欠陥はいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合である、請求項１乃至７のいずれか一項に記載の光学フィルムの欠陥判別方法。 The foreign matter in the region is a foreign matter which is not a cluster defect, and the cluster defect is a set of foreign matters including a foreign matter at the center when there are two or more different foreign matters in a circle having a radius of 5 mm around any one foreign matter. in it, a defect determination method of an optical film according to any one of claims 1 to 7. 前記領域中の異物は微細欠陥ではない異物であって、前記微細欠陥は８ピクセル×８ピクセルの正四角形の内部に含まれる異物である、請求項１乃至７のいずれか一項に記載の光学フィルムの欠陥判別方法。 The optical device according to any one of claims 1 to 7 , wherein the foreign matter in the region is a foreign matter that is not a fine defect, and the fine defect is a foreign matter contained in a regular square of 8 pixels x 8 pixels. Film defect discrimination method. 前記領域中の異物はクラスター欠陥及び微細欠陥ではない異物であって、前記クラスター欠陥はいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合であり、前記微細欠陥は８ピクセル×８ピクセルの正四角形の内部に含まれる異物である、請求項１乃至７のいずれか一項に記載の光学フィルムの欠陥判別方法。 The foreign matter in the region is a foreign matter which is not a cluster defect and a fine defect, and the cluster defect includes a central foreign matter when two or more different foreign matters exist in a circle having a radius of 5 mm around any one foreign matter. a collection of foreign matter, the fine defects are foreign matter contained in the interior of the square 8 pixels × 8 pixels, a defect determination method of an optical film according to any one of claims 1 to 7. （Ｓ１）移送される光学フィルムを撮影して異物が存在する領域を選別する段階と、
(Ｓ１-Ａ）前記領域中の異物のうちいずれか一つの異物を中心に５ｍｍ半径の円内に相違する異物が２以上存在すると中心の異物を含む前記異物の集合をクラスター欠陥と判別する段階と、
(Ｓ１-Ｂ）前記クラスター欠陥と判別されていない異物のうち８ピクセル×８ピクセルの正四角形の内部に含まれる異物は微細欠陥と判別する段階と、
（Ｓ２）前記微細欠陥と判別されていない異物のうち、移送方向に平行な二辺とそれに垂直な二辺とからなる長方形が最小面積で異物を含む場合に前記移送方向に平行な辺がそれに垂直な辺より大きい場合、線状良品性異物と判定して欠陥から除外する段階と、
前記線状良品性異物と判定されていない異物のうちその長辺の長さが３０ピクセル以下であり、下記数式１の欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル以下である場合、直線状良品性異物と判定して欠陥から除外する段階と、を含む、光学フィルムの欠陥判別方法。
(S1) A step of photographing an optical film to be transferred and selecting a region where foreign matters exist;
(S1-A) When two or more different foreign objects exist in a circle having a radius of 5 mm centering on any one of the foreign substances in the region, the set of the foreign substances including the central foreign substance is determined as a cluster defect. When,
(S1-B) a step of discriminating foreign matter contained in a regular square of 8 pixels × 8 pixels among the foreign matters not discriminated as cluster defects as fine defects;
(S2) Among the foreign matters not identified as the fine defects, when a rectangle composed of two sides parallel to the transfer direction and two sides perpendicular thereto includes the foreign matter with a minimum area, the side parallel to the transfer direction is If it is larger than the vertical side, it is determined as a linear non-defective foreign material and excluded from the defect ,
Among the foreign matters not determined to be the linear non-defective foreign matter, the length of the long side thereof is 30 pixels or less, the defect density of the following Equation 1 is 40% or less, and the shortened length of the center line image of the foreign matter A method for determining defects in an optical film, comprising: determining that the foreign material is a linear non-defective foreign material and excluding it from defects.
（Ｓ２）段階の長方形の長辺の長さが長辺の長さが５ピクセル以上であり、短辺の長さが長辺の０．８倍以下の異物である場合、線状良品性異物と判定する、請求項１１に記載の光学フィルムの欠陥判別方法。 (S2) When the length of the long side of the rectangle in the stage is a foreign matter having a long side length of 5 pixels or more and a short side length of 0.8 times or less of the long side, a linear non-defective foreign matter The optical film defect determination method according to claim 11 , wherein: 前記異物の長辺の長さが３０ピクセル超過であれば大型欠陥と判定する、請求項１２に記載の光学フィルムの欠陥判別方法。 The optical film defect determination method according to claim 12 , wherein if the length of the long side of the foreign matter exceeds 30 pixels, it is determined as a large defect. 前記異物の長辺の長さが３０ピクセル以下であり、前記数式１による欠陥密度が４０％以下であり、前記異物の中心線映像の短縮長さが３ピクセル超過であれば曲線状欠陥と判定する、請求項１２に記載の光学フィルムの欠陥判別方法。 If the length of the long side of the foreign material is 30 pixels or less, the defect density according to Equation 1 is 40% or less, and the shortened length of the center line image of the foreign material exceeds 3 pixels, it is determined as a curved defect. The optical film defect determination method according to claim 12 . 長辺の長さが３０ピクセル以下であり、数式１の欠陥密度が４０％超過である異物に対して欠陥密度が７５％以下の異物は、斜方状良品性異物と判定して欠陥から除外する段階をさらに含む、請求項１２に記載の光学フィルムの欠陥判別方法。 Foreign matter having a defect length of 75% or less with respect to a foreign matter having a long side length of 30 pixels or less and the defect density of Equation 1 exceeding 40% is determined to be an oblique non-defective foreign matter and excluded from the defect. The method for discriminating defects in an optical film according to claim 12 , further comprising the step of: 欠陥密度が７５％超過である異物のうち前記円の内部位置による明度グラフがその勾配値がプラスからマイナスに転じる箇所が２以上存在する異物はエンボス状良品性異物と判定して欠陥から除外する段階をさらに含む、請求項１５に記載の光学フィルムの欠陥判別方法。 Among foreign matters having a defect density exceeding 75%, a foreign matter having two or more places where the gradient value of the inner circle position changes from positive to negative is determined as an embossed non-defective foreign matter and excluded from the defect. The optical film defect determination method according to claim 15 , further comprising a step. 前記部分でグラフの勾配値がプラスからマイナスに転じる箇所が３以上存在する異物はエンボス状良品性異物と判定する、請求項１６に記載の光学フィルムの欠陥判別方法。 The optical film defect determination method according to claim 16 , wherein a foreign matter having three or more portions where the gradient value of the graph changes from positive to negative in the portion is determined as an embossed non-defective foreign material.
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