Abstract: An electrochromic display composed of a transparent electroconductive membrane, an electrochromic membrane, an ion-exchange membrane and a counter electrode in a laminated structure. The ion-exchange membrane is a bipolar ion-exchange membrane composed of at least one cation-exchange membrane layer having cation-exchange groups and at least one anion-exchange membrane layer containing anion-exchange groups in a laminated structure. The electrochromic display has a superior response speed, contrast and resolving power as well as a long service life.

Abstract: A novel selector device for the determination of the conductivity-type in a semiconductor wafer utilizes the determination of the polarity of the electromotive force produced in the wafer by the Hall effect. The device comprises two pairs of probes in diagonal arrangement for supplying an electric current through the wafer and for detecting the electromotive force, respectively, by contacting the wafer surface, and a pair of permanent magnets positioned oppositely with the wafer in between to produce a magnetic field perpendicular to the wafer. One of the permanent magnets is located within the circumference determined by the probes.