| 摘要 |
A spectrometer is incorporated to a conventional lensometer. The spectrometer includes a uniform extended light source including a light source having visible and ultraviolet emission and an extending integrating sphere including ultraviolet transmission. In the preferred embodiment, an Ebert spectrometer is utilized, although other spectrometers may be used as well. Light is emitted from the light source through the spectacle lens to be tested to a spherical reflecting surface. Upon reflection, the light is incident to a grating, retro reflected to the spherical surface and thereafter reflected for incidence to a charge coupled device for analysis of the generated spectrum. The system is provided with a slit and a field stop dimensioned so that through all ranges of lenses expected to be tested within designated tolerances of sphere, cylinder and prism, the spectrometer sees only and always a portion of the uniform extended light source. Preferably, the stop is located exterior of the spectrometer-although location of the stop at the reflecting surface, or grating can be operable. There results a lensometer capable of measurements of lens power and glass absorption characteristics, the latter measurement not being affected by the power or decentration of the measured lens.
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