A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. This method is also highly suitable for automatisation by using a computer. A tape travel speed of an archive VTR 4 is changed in response to the picture compression rate. A heat insulating member is provided to at least a part of the light-emitting section and the other one of the sealing sections of the light-emitting tube. , an alkali vapor cell, using anti-resonant reflecting optical waveguides, or ARROW waveguides, on a substrate. The server system computes a route to the destination and transmits the computed route to the in-vehicle system.