Patent ID: 7034932

Claim:
An object-sensing device comprising a light source for total reflection and a light source for scattering, wherein an outer surface of a transparent substrate is used as a sensing surface on which an incident light admitted into the transparent substrate from the light source for total reflection is reflected, and an incident light admitted into the transparent substrate from the light source for scattering is irradiated, the light source for total reflection, the transparent substrate and a light receiver are arranged such that the reflected light of the light source for total reflection from the sensing surface can be received by the light receiver, and the light source for scattering and the light receiver are arranged such that scattered light of the light source for scattering from the sensing surface can be received, the object-sensing device comprising: an object sensor for detecting a change due to an object in a signal level from the light source for total reflection in a photo detection signal detected by the light receiver so as to detect a presence of the object; and a light-scattering-object sensor for detecting a change due to an object in a signal level from the light source for scattering in a photo detection signal detected by the light receiver so as to detect whether or not the object is a light scattering object, wherein the light source for total reflection and the light source for scattering are switched for operation.