Abstract
A spectrophotometer for measuring bi-directional/semi-spherical reflectance of a surface in a wide spectrum has been developed. The spectrophotometer consists of light source section, test section and photometric section. In the light source section, to uniformly irradiate the test surface, radiation emitted from a halogen lamp is collimated to a beam with a diameter of 20 mm by a concave mirror. There are two types of the test sections for bi-directional/semi-spherical reflectance measurements. In the test section for bi-directional reflectance measurement, the test piece holder has a mechanism to change both the direction of incident radiation and the direction to the photometric section. The other test section has two parabolic mirrors and a small integrating sphere to collect the radiation scattered to the half hemisphere. The radiation reflected by a test surface is derived to the photometric section and measured by three CCD cameras that respectively cover the ultraviolet, visible and infrared spectrums.
