Unveiling Ceremony for IEEE Milestone Plaque (April 21, 2017）

Media 2017.04.21

Invention of a Temperature-Insensitive Quartz Oscillation Plate, 1933.
In April 1933, Issac Koga of the Tokyo Institute of Technology reported cutting angles that produced quartz crystal plates having a zero temperature coefficient of frequency. These angles, 54°45′ and 137°59′, he named the R1 and R2 cuts. Temperature-insensitive wuartz crystal was used at first for radio transmitters and later for clocks, and has proven indispensable to all radio communication systems and much of information electronics.

　　　　　　Left：President, Yoshinao MISHIMA，Right：Executive Vice President, Makoto ANDO

　
　　　　　　　　　Attendees　　　　　　　　　　　　　　　　　　　　　Monument

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