参考文献

Doi, Takashi; Yoshida, Yoshihiro; Douyama, Daisuke; Katsura, Ryousuke; Fujitsu, Satoru; Yasuda, Shinji; Kimura, Keisuke; Oomori, Kiyoshi Patent: US2012/323021 A1, 2012 ; Location in patent: Page/Page column 15 ;