Patent ID: 7622698

Claim:
A detection head comprising: a light-emitting element and a light-receiving element which are provided on a surface; and a light-transmissive member which covers the light-emitting element and the light-receiving element, wherein the light-emitting element includes a light-emitting region, and the light-receiving element includes a light-receiving region which is spaced from the light-emitting region along the surface, wherein the light-receiving region is closer to the light-emitting region than a region illuminated with light rays which are totally reflected by an interface between the light-transmissive member and the outside thereof and are directed toward the light-receiving element, and wherein the light-transmissive member is formed of a light-transmissive resin covering over the light-emitting element and the light-receiving element and a light-transmissive glass covering over the light-transmissive resin.