カテゴリ: 論文誌(論文単位)グループ名: 【A】基礎・材料・共通部門発行日: 2011/09/01タイトル(英語): Visualization of Electrical Trees by 80 MHz-band Pulsed Ultrasound著者名: 木田 智志（豊橋技術科学大学），村上 義信（豊橋技術科学大学），長尾 雅行（豊橋技術科学大学），穂積 直裕（愛知工業大学）著者名(英語): Satoshi Kida (Toyohashi Univercity of Technology), Yoshinobu Murakami (Toyohashi Univercity of Technology), Masayuki Nagao (Toyohashi Univercity of Technology), Naohiro Hozumi (Aichi Institute of Technology)キーワード: 電気トリー，超音波，音響インピーダンス，可視化，絶縁機器 electrical treeing，ultrasound，acoustic impedance，visualization，insulating device要約(英語): Power modules are often molded with a resin, such as epoxy, for their protection and downsizing. The resin, which contains inorganic filler, is usually non-transparent. As optical inspection is not realistic, non-destructive inspections using X-ray or ultrasound is being performed. As for cracks and so-called “electrical tree” in the insulation, ultrasound may bring a good contrast, because there is a big difference in acoustic impedance between resin and air.There are some reports on ultrasonic observation for electrical trees, however, as thick specimens were employed, the spatial resolution was very poor due to the limitation of available frequency range. However, the diameter of electrical tree path is as thin as 5 μm. Enough resolution can't be obtained by the measurement with a low frequency range. Based on the above background, we tried to observe a “close but small” tree by ultrasonic imaging. Using the wide-band ultrasonic microscope, it was examined if a tree with 0.5 mm in scale could be observed with its fine structure.An ultrasonic image, in which branching in the tree can be discriminated. The spatial resolution was determined as 40∼50 μm. An image processing was carried out in order to acquire a clearer image. Assuming the Gaussian as a blur function, the original image was deconvolved.本誌: 電気学会論文誌A（基礎・材料・共通部門誌） Vol.131 No.9 （2011） 特集：自然災害軽減のための電磁界技術本誌掲載ページ: 792-796 p原稿種別: 論文／日本語電子版へのリンク: https://www.jstage.jst.go.jp/article/ieejfms/131/9/131_9_792/_article/-char/ja/
