Gas sensor

A gas sensor comprising:

• a substrate;
• a light-emitting element provided at a front surface that is one surface of the substrate or embedded in the substrate;
• a light-receiving element that is provided at the front surface of the substrate or embedded in the substrate and that receives light emitted from the light-emitting element;
• a light guide that guides light emitted from the light-emitting element to the light-receiving element, and
• a plurality of external connection terminals at a rear surface that is an opposite surface to the front surface of the substrate, with at least a portion of the plurality of external connection terminals electrically connected to the light-emitting element and the light-receiving element, wherein
• the plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals, and
• the light guide is adhered to the substrate at an adhesion surface of the front surface of the substrate, and the adhesion surface is provided such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two points in the adhesion surface.

A gas sensor comprising:

• a substrate;
• a light-emitting element provided at a front surface that is one surface of the substrate or embedded in the substrate;
• a light-receiving element that is provided at the front surface of the substrate or embedded in the substrate and that receives light emitted from the light-emitting element;
• and
• a plurality of external connection terminals at a rear surface that is an opposite surface to the front surface of the substrate, with at least a portion of the plurality of external connection terminals electrically connected to the light-emitting element and the light-receiving element, wherein
• the plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals,
• an integrated circuit that computes a concentration of a gas is located, in plan view, within a region in which the plurality of external connection terminals is arranged.