摘要 |
An optical device for measuring reflectance, and, optionally, transmission, of a substrate. The device has first and second toroidal mirrors and first and second optical fibers. The first toroidal mirror directs light from the first optical fiber toward the substrate, which reflects from the substrate and is collected by the second toroidal mirror. The light collected by the second toroidal mirror is focused into the second optical fiber. There are many possible orientations for the fibers and mirrors. The device may also have a fold mirror for directing the light toward the substrate. Optionally, the present invention includes components for measuring transmission of the substrate. The components for measuring transmission may include fibers and toroidal mirrors. Preferably, reflectance and transmission are measured at the same location. If a fold mirror is used, the fold mirror has a gap to allow transmission measurements to be performed at the same location as reflectance measurements. The present invention includes several possible arrangements for fibers and toroidal mirrors.
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