Ceramic substrate heater with metallic heating element

摘要

The heater has a substrate of ceramic material carrying a heating element connected electrically through lead portions to a DC source. A conductor retains ionised elements and is of the same material as the heating element, on the other side of the sheet and thick film-printed in the same manner as the heating element. The lead portions are wider than the heating element to restrict undesired heat generation. A through hole provided at the lead portion of the negative terminal allows one end of the conductor to be electrically connected with the negative lead portion. Platinum wires are for connection to the DC source. A ceramic green sheet is used for fixing the wires in position. Through holes allow the lead portions to be connected to the wires. A positive pole of the DC source is connected to the other lead portion. When a DC voltage is applied between the lead portions, the heating element generates heat through electric conduction. The ionised elements do not migrate towards the low electric potential side through the heating element because the conductor for retaining ionised elements is provided on the back of the ceramic substrate.