Ngk Insulators, Inc.

Yusuke Ogiso

Yoshimasa Kondo

Katsunao Uenishi

Tomoki Nagae

Atsushi Watanabe

Ayato Koizumi

Tatsuya Kuno

A wafer placement table includes: a ceramic plate having a wafer placement surface on an upper surface and a built-in electrode; a plug placement hole extending through the ceramic plate from a lower surface to the upper surface; a plug placed in the plug placement hole and allowing gas to pass therethrough; and a plug joint joining an outer edge of an upper surface of the plug and an upper opening edge of the plug placement hole and covering the outer edge of the upper surface of the plug from above.

Wafer placement table

A sensor element includes: an element base which has a gas inlet in one end portion thereof and into which a measurement gas is introduced through the gas inlet; and a leading-end protective layer disposed around an outer periphery of the element base in a predetermined range from the one end portion, having a laminated structure of: an inner layer having coarse voids with a size of 1 μm or more in a matrix region having a framework structure formed by porous pieces each having fine pores with a pore diameter of 10 nm or more and less than 1 μm; and an outer layer disposed to cover the inner leading-end protective layer, and having a lower porosity than the inner layer, and the inner layer has: an overall porosity of 40% or more and 90% or less; and a coarse porosity of 1% or more and 55% or less.

Sensor element of gas sensor and method for forming protective layer of sensor element

A sensor element includes an element body having a measurement-object gas flow section formed therein, and a porous protective layer arranged to cover first to fifth surfaces of the element body. When an external wall that is the thinnest of parts of an external wall which constitute the element body and extend from the measurement-object gas flow section to the first to fifth surfaces is defined as a thinnest external wall and a surface corresponding to the thinnest external wall is defined as a closest surface, a part of the protective layer which covers the closest surface overlaps the entirety of the thinnest external wall when viewed in a direction perpendicular to the closest surface, and has one or more internal spaces formed therein which overlaps 80% or more of the thinnest external wall when viewed in the direction perpendicular to the closest surface.

Sensor element and gas sensor with enhanced waterproofing

A sensor element includes an element body and a porous protective layer arranged to cover a part of a surface of the element body. The protective layer includes an inlet protective layer arranged to cover a gas inlet formed in the surface of the element body, and at least a part of a face included in the surface of the element body, the face on which the gas inlet is opens, and an arithmetic average roughness Rap of an inner peripheral surface of an internal space of the inlet protective layer satisfies at least one of conditions below: the arithmetic average roughness Rap is 8 μm or more, and the arithmetic average roughness Rap is higher than an arithmetic average roughness Rac of a bonding surface of the protective layer, the bonding surface at which the protective layer is bonded to the element body.

Growing community of inventors

Nagakute, Japan

Yusuke Ogiso