US Patent 7456971 Optical gas sensing apparatus

An optical gas sensing apparatus for sensing gas includes a tubular housing member, a column light source member, a column light sensing element member and an adhesive. The tubular housing member has a light-reflecting inner surface. The column light source member is provided to a first end portion of the housing member, wherein the light source member has a light source, which emits light. The column light sensing element member is provided to a second end portion of the housing member, wherein the light sensing element member has a light sensing element, which senses the light emitted by the light source. The adhesive connects the housing member to at least one of the light source member and the light sensing element member.