DEFECT INSPECTION DEVICE AND DEFECT INSPECTION METHOD FOR TRANSPARENT TABULAR BODY

PROBLEM TO BE SOLVED: To provide a defect inspection device and a defect inspection method for a transparent tabular body, which are capable of accurately measuring a size of a defect existing in a transparent tabular body.SOLUTION: A defect inspection device 10 for a transparent tabular body uses a transmissive dark-field inspection optical system including a light source 14 and a reflective dark-field inspection optical system including the light source 14 and a mirror 16 to perform defect inspection on one internal defect B, so that the internal defect B can be inspected with high detection sensitivity. Further, the internal defect B is irradiated with light from all directions except from above on the downstream side and right above by action of a diffusing plate 30, that is, the entire circumference of the outline of the internal defect B can be brightened, so that a defect image showing a distinct outer shape of the internal defect B can be obtained, and therefore, the size of the internal defect B can be measured more accurately. 【課題】透明板状体に存在する欠点のサイズを正確に測定できる透明板状体の欠点検査装置及び欠点検査方法を提供する。【解決手段】本発明の透明板状体の欠点検査装置１０は、光源１４を備えた透過型の暗視野検査光学系と、光源１４とミラー１６を備えた反射型の暗視野検査光学系とを使用して、一つの内部欠点Ｂに対して欠点検査を行う。これにより、内部欠点Ｂに対して検出感度の高い検査ができる。また、内部欠点Ｂには、拡散板３０の作用によって内部欠点Ｂの上方下流側及び真上方向を除く全ての方向から光が当たるので、すなわち内部欠点Ｂの輪郭の全周を光らせることができるので、内部欠点Ｂの外形が明確な欠点画像を得ることができ、よって、内部欠点Ｂのサイズをより正確に測定できる。【選択図】図１