Patent ID: 7183534
Filing Date: 2007-02-27
Classification: G01N,G03G

Abstract:
1. A photodetector for detecting at least one of light reflected from a surface to be measured and light scattered from the surface to be measured, comprising: a light emitting portion for emitting light; a light receiving portion for sensing light; and a light guiding member for substantially totally reflecting the light thereinside to guide the light from the light emitting portion to the surface to be measured, and substantially totally reflecting detection light thereinside to guide the detection light from the surface to be measured to the light receiving portion, wherein the light guiding member has a sheet-shaped optical transmission medium disposed at a portion facing to the surface to be measured and transmitting the light by internal reflection, and including an optical aperture spaced from and facing to the surface to be measured, wherein the sheet-shaped optical transmission medium includes a light applying portion for applying the light to the surface to be measured and a light detecting portion for detecting the light from the surface to be measured as the optical aperture; wherein the sheet-shaped optical transmission medium is a plurality of sheet-shaped optical transmission media; and wherein the light applying portion and the light detecting portion are formed in different parts of the sheet-shaped optical transmission medium.