| Number | Name | Date | Kind |
|---|---|---|---|
| 4471259 | Stoermer et al. | Sep 1984 | A |
| 5449965 | Tsuru | Sep 1995 | A |
| 5596243 | Tsuru et al. | Jan 1997 | A |
| 6229249 | Hatanaka et al. | May 2001 | B1 |
| 6833654 | Rubach | Dec 2004 | B2 |
| 7135810 | Okajima | Nov 2006 | B2 |
| 7429759 | Isokawa | Sep 2008 | B2 |
| 7521843 | Naruse | Apr 2009 | B2 |
| 7557493 | Fujimoto | Jul 2009 | B2 |
| 7564177 | Yoshimatsu et al. | Jul 2009 | B2 |
| 20020123163 | Fujii | Sep 2002 | A1 |