DEFECT INSPECTION METHOD OF LIGHT TRANSMISSIVE PLATE-LIKE BODY

To provide a defect inspection method of a light transmissive plate-like body that can detect defects of the light transmissive plate-like body and also can determine whether the defects are flaws.SOLUTION: A defect inspection method includes the steps of: applying light to a focal position of an imaging section while rotating an irradiation section 2 disposed on a virtual circle with a light axis of the imaging section 1 as a center along the virtual circle, and acquiring multiple image data having different irradiation rotational angles by the imaging section; specifying two-dimensional coordinates of defects from the respective acquired image data; and determining the specified defects as flaw defects when a change rate of luminance is larger than a predetermined threshold among multiple image data having different irradiation angles, and determining them as deposit when the change rate of luminance is smaller than the threshold.SELECTED DRAWING: Figure 3 【課題】光透過性板状体の欠陥検出を行うとともに、欠陥が傷であるか付着物であるかを判別することのできる光透過性板状体の欠陥検査方法を提供する。【解決手段】撮像部１の光軸を中心とする仮想円上に配置された照射部２を前記仮想円に沿って回転させながら前記撮像部の焦点位置に照射し、前記撮像部により、照射回転角度の異なる複数の画像データを取得する工程と、取得した各画像データから欠陥の二次元座標を特定する工程と、特定された前記欠陥について、照射方向の異なる複数の画像データの間での輝度の変化率が所定の閾値より大きいと傷の欠陥と判定し、輝度の変化率が前記閾値より小さいと付着物と判定する工程と、を備える。【選択図】図３