Patent ID: 9513218
Filing Date: 2016-12-06
CPC Classification: G01N,G03G

Claim Text:
1. An optical sensor comprising: a light source to illuminate an object with light of a first linear polarization; a first optical detector disposed on a path of the light illuminated from the light source and specularly reflected by the object, light detected by the first optical detector including reflection light from a surface of the object and reflection light from inside the object; a first optical element to separate the light reflected by the object into the first linear polarization in a first direction and a second linear polarization in a second direction orthogonal to the first direction; a second optical detector to receive the second linear polarization in the second direction separated by the first optical element; a third optical detector to receive the first linear polarization in the first direction separated by the first optical element; and a processor to (i) obtain an amount of specular reflection of the first linear polarization by the object on the basis of an output signal of the first optical detector and an output signal of the second optical detector, (ii) obtain an amount of specular reflection of the second linear polarization on the basis of the output signal of the first optical detector and an output signal of the third optical detector, (iii) calculate a reflection rate of the first linear polarization based on the obtained amount of specular reflection of the first linear polarization, (iv) calculate a reflection rate of the second linear polarization based on the obtained amount of specular reflection of the second linear polarization, and (v) determine a material type of the object based on the reflection rate of the first linear polarization and the reflection rate of the second linear polarization.