| 摘要 |
PURPOSE:To provide an indicator which is not affected by a leakage wave by constituting the indicator of an optical fiber. CONSTITUTION:When a high frequency heating device is turned ON and a high- frequency oscillation is started, an oven lamp 15 is lit at the same time. A part of light from the oven lamp 15 advances into an optical fiber 19. The light is transmitted to the other end of the optical fiber 19 without almost attenuating, and is discharged to the outside, thereafter shining an indication plate 18 and indicating the presence or absence of the high-frequency oscillation. An interval L between the end surface of the optical fiber 21 and an indication plate 23 is assumed to a certain extent, and knurling is applied to the inner surface of the indication plate 23 and light is subjected to irregular reflection whereby the indication plate 23 wider than the section of the optical fiber 21 can be illuminated. |
