| 摘要 |
<p>PURPOSE:To secure an automatic performance of a proper cleansing for the field radiation type electronic gun to be used for the scan-type electronic microscope, by providing a cleansing circuit which gives a heating degassing onto the surface of the field radiation cathode-ray tube plus a circuit which detects the vacuum degree at the cleaning time in order to have cleansing again in accordance with the detection output.</p> |
