Patent ID: 8685710
Filing Date: 2014-04-01
Classification: G01N

Abstract:
1. A photodetector for detecting light emitted from a sample on a substrate as a measurement object, the photodetector comprising: an irradiation optical device comprising a first optical waveguide guiding irradiation light, and a first lens for receiving and gathering the irradiation light from the first optical waveguide and irradiating the sample as the measurement object; and a reception optical device comprising a second lens for gathering light emitted from the sample and a second optical waveguide for receiving the light at an input-side end surface from the second lens and guiding the light to a measuring unit; and an irradiation light spot converting portion which converts a spot shape of the irradiation light output from the irradiation optical device in such a manner that the spot shape becomes circular on an installation plane on which the measurement object is placed, wherein, the irradiation optical device and the reception optical device are separate light guiding paths, each optical device having an optical axis oriented at a different angle with respect to an axis perpendicular to the installation plane on which the measurement object is placed, the optical axis of the reception optical device has the angle other than 0 degrees with respect to the axis perpendicular to the installation plane, the first optical axis of the irradiation optical device forms an angle, except for 0 degree, with respect to a normal line of the installation plane on which the measurement object is placed, and the reception optical device is of a confocal optical device in which a focal point on the sample is identical to a focal point at the input-side end surface of the second optical waveguide of the reception optical device.