Optical measurement device and optical measurement method
An illumination device irradiates a predetermined area with measurement light whose wavelength changes over time. A light reception device includes an optical sensor that detects diffuse transmission light of an object located in the predetermined area. The light reception device is structured such that the optical sensor receives a component of the diffuse transmission light through the object which propagates in a direction deviated from an optical axis of the measurement light.
1 . An optical measurement device comprising:
a conveyance device having a through-opening through which light passes, the conveyance device being structured to hold an object by negative pressure applied via the through-opening and to convey the object so as to pass through a predetermined region;
an illumination device structured to irradiate a predetermined area with measurement light whose wavelength changes over time; and
a light reception device including an optical sensor structured to detect diffuse transmission light through the object passing through the predetermined area, wherein
the optical measurement device is structured such that an optical path from the illumination device to the light reception device passes through the through-opening, and only the object is present on the optical path, and
the light reception device is structured such that the optical sensor receives a component of the diffuse transmission light through the object which propagates in a direction deviated from an optical axis of the measurement light.
2 . The optical measurement device according to claim 1 , wherein
the light reception device further includes a condenser optical system having an optical axis that is perpendicular to the optical sensor and passes through a center of the optical sensor, and
wherein the light reception device is disposed such that the optical axis of the condenser optical system passes through the predetermined area, and is non-parallel to the optical axis of the measurement light.
3 . The optical measurement device according to claim 2 , wherein
the optical axis of the measurement light is perpendicular to the object, and
the optical axis of the condenser optical system is non-perpendicular to the object.
4 . The optical measurement device according to claim 2 , wherein
the optical axis of the measurement light is non-perpendicular to the object, and
the optical axis of the condenser optical system is perpendicular to the object.
5 . The optical measurement device according to claim 2 , wherein
the optical axis of the measurement light is non-perpendicular to the object, and
the optical axis of the condenser optical system is non-perpendicular to the object.
6 . The optical measurement device according to claim 1 , wherein
the light reception device has an entrance window and an optical axis of the light reception device is defined as a straight line that passes through a center of the entrance window and is perpendicular to the entrance window, and
wherein the light reception device is disposed such that the optical axis of the light reception device is parallel to the optical axis of the measurement light, and the optical axis of the light reception device is apart from the optical axis of the measurement light.
7 . The optical measurement device according to claim 1 , wherein
the light reception device further includes
a condenser optical system, and
a mask structured to block the component of the diffuse transmission light through the object which propagates in the direction of the optical axis of the measurement light.
8 . The optical measurement device according to claim 1 , wherein the measurement light is pulse light whose wavelength changes over time in one pulse.