An adjusting bolt is screwed into a nut attached to a dolly, and is disposed such that a central axis thereof is parallel to a closing and opening direction of a contact. The portable expandable screen has a plurality of panels assembled in a telescoping manner like an accordion. The thin films are formed by heating the base plate and emitting a deposition material from a deposition source. The time corresponding to the final delay is then determined by using a phase interpolator to generate a range of phase offset signals having known delay times until a phase offset signal has the same delay as the final delay.