Ceramic heater and gas sensor element using the same

Patent metadata

Field	Value
Publication number	US-9651517-B2
Application number	US-201514617038-A
Country	US
Kind code	B2
Filing date	Feb 9, 2015
Priority date	Feb 11, 2014
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A ceramic heater has a plate substrate made of ceramic and a conductive layer. The conductive layer has a heating section and a pair of lead sections. When receiving electric power, the conductive layer generates heat. The lead sections are formed at one section on the plate substrate adjacent to each other in a width direction and formed along a longitudinal direction on the plate substrate. The heating section is formed to meander on the other section in the plate substrate and both ends of the heating section are connected to the lead sections, respectively. In particular, central sections formed at a central area of the heating section in the width direction and the longitudinal direction have a resistance value which is lower per unit length than a resistance value of other linear shaped sections of the heating section.

First claim

What is claimed is:

1. A ceramic heater comprising:
a plate substrate made of ceramic; and a conductive layer configured to generate heat when receiving electric power, wherein the conductive layer comprises: a pair of lead sections; and a heating section, wherein
the lead sections are formed on a first section of the plate substrate and are adjacent to each other in a width direction which is perpendicular to the longitudinal direction, and
the heating section is formed in a meandering shape in a second section on the plate substrate, and both end sections of the heating section are connected respectively to the lead sections, and
the heating section comprises linear shaped sections formed at a central section in the width direction and the longitudinal direction of the heating section, the linear shaped sections having a first resistance value per unit length which is lower than a second resistance value per unit length of other linear shaped sections formed on the other section outside the central section of the heating section.

2. The ceramic heater according to claim 1 , wherein the heating section comprises:
a pair of outer linear shaped sections formed on the plate substrate along the longitudinal direction;
a pair of inner linear shaped sections formed on the plate substrate parallel to the outer linear shaped sections and inner of the outer linear shaped sections in the width direction,
first end sections of the inner linear shaped sections are connected together, and a second end section of each of the outer linear shaped sections is connected to a second end section of each of the inner linear shaped sections in order to form the heating section,
wherein a central section of each of the inner linear shaped sections in the longitudinal direction has a resistance value per unit length which is lower than a resistance value per unit length of each of both end sections of the inner linear shaped sections, and a resistance value per unit length of each of the outer linear shaped sections.

3. A gas sensor element comprising:
the ceramic heater of claim 2 ; and
a solid electrolyte body having oxygen ion conductivity laminated with the ceramic heater, wherein
a target gas chamber is formed on a first surface of the solid electrolyte body, a reference gas chamber is formed on a second surface of the solid electrolyte body,
a pair of electrodes is formed on the solid electrolyte body, one electrode is formed on the first surface, and the other electrode is formed on the second surface of the solid electrolyte body, and the pairs of electrodes detects an oxygen concentration in a target gas introduced into the target gas chamber, and
the central sections, formed along the longitudinal direction, in the inner linear shaped sections are arranged to face the electrodes.

4. The ceramic heater according to claim 2 , wherein a central section of each of the outer linear shaped sections in the longitudinal direction has a resistance value per unit length which is higher than a resistance value per unit length of other section of each of the outer linear shaped sections.

5. The ceramic heater according to claim 2 , wherein the heating section is made of a same type of conductive material and has a same thickness, and each of the outer linear shaped sections and the inner linear shaped sections has a different width in order to have a different resistance value.

6. The ceramic heater according to claim 5 , wherein a width ratio of the central linear shaped section in each of the inner linear shaped sections to each of the other linear shaped sections is within a range of 1.2 to 1.7, and a width ratio of the central linear shaped section in each of the outer linear shaped sections to each of the other linear shaped sections is within a range of 0.5 to 0.9.

7. A gas sensor element comprising:
the ceramic heater of claim 1 ; and
a solid electrolyte body having oxygen ion conductivity laminated with the ceramic heater, wherein
a target gas chamber is formed on a first surface of the solid electrolyte body, a reference gas chamber is formed on a second surface of the solid electrolyte body,
a pair of electrodes is formed on the solid electrolyte body, one electrode is formed on the first surface, and the other electrode is formed on the second surface of the solid electrolyte body, and the pairs of electrodes detects an oxygen concentration in a target gas introduced into the target gas chamber, and
the central sections, formed along the longitudinal direction, in the inner linear shaped sections are arranged to face the electrodes.

Assignees

• Denso Corp

Inventors

• Satou Chimato

Classifications

• H05B3/262

  the insulating base being an insulated metal plate · CPC title

• G01N27/4067 Primary

  Means for heating or controlling the temperature of the solid electrolyte · CPC title

• H05B3/10

  Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor · CPC title