| 摘要 |
<P>PROBLEM TO BE SOLVED: To secure superior transmission quality and a wide dynamic range when spatial optical transmission is performed by using a visible optical source, such as a blue photoexcitation type white LED. <P>SOLUTION: When distance between a transmitter and a receiver is short, a perimeter photoelectric conversion unit 12S receives light, which contains many optical yellow factors, from phosphor. The signal level of a signal level detector 22 comes to exceed a predetermined threshold, and a change-over switch 15 is switched to the side of an equalizer 16SY suitable characteristic for optical yellow factors. When the distance between the transmitter and the receiver is long, the perimeter photoelectric conversion unit 12S receives light, which contains optical blue factors, from LED. The signal level of a signal level detector 22 does not exceed the predetermined threshold, so the change-over switch 15 is switched to the side of an equalizer 16SB, which is suitable characteristic for optical blue factors. <P>COPYRIGHT: (C)2009,JPO&INPIT |
