Ceramic heater and oxygen sensor

• Main Authors: KUROKI; YOSHIAKI, YANAGI; KUNIO, KOJIMA; TAKAO
• Format: Patent
• Language: English
• Published: 20.04.1999
• Edition: 6
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

A ceramic heater for heating a sensor such as an oxygen sensor has a ceramic substrate and a heater pattern formed on the substrate. A heater pattern 22 is tightly interposed between first and second alumina substrates 15 and 21. This heater pattern 22 has a meandering heating section 25 and a pair of leads 26 for connecting both ends of the heating section 25 to two terminals at the base side end. The heating section 25 is divided into a tip side subsection 25a located near the tip side end of the device, and a base side subsection 25b. Specifically, the wire width is made greater in the tip side subsection 25a than in the base side subsection 25b so that the resistance per unit length is lower in the tip side subsection 25a. The thus-designed heater section 25 produces a less amount of heat in the tip side subsection than in the base side subsection, and this distribution of heat generation can reduce the possibility of cracks and breakage of a wire.