| 摘要 |
<p> Provided is a reflective optical-film-thickness-measurement device attached to a substrate holder of a rotary optical-thin-film-forming device, the optical-film-thickness-measurement device measuring the thickness of the optical thin film on a rotating substrate and not being readily affected by variation in angle of the rotating substrate. The present invention is provided with: a projection-side lens unit provided with a projection part (43) for projecting measurement light towards a rotating substrate (S), and projection-side lenses (51, 56) disposed between the substrate (S) and the projection part (43), the projection side lenses (51, 56) receiving the measurement light emitted from the projection part (43) and guiding the measurement light to the substrate (S); and a reception-side lens unit provided with a light reception part (44) for receiving light reflected by the substrate (S) from the measurement light, and reception-side lenses (52, 57) disposed between the substrate (S) and the reception part (44), the reception side lenses (52, 57) receiving the light reflected by the substrate (S) and guiding this reflected light to the reception unit (44). At least some of the optical path of the reception-side lens unit and the optical path of the projection-side lens unit are separate, and the active area of the projection-side lens unit is less than the active area of the reception-side lens unit.</p> |
