| 摘要 |
A device for the measurement of the distance to an optical interface comprises a first light source (18a) generating polychromatic light. A first spectral source function (SFa), which is associated with the first light source (18a) and describes the dependence of the intensity of the generated light on the wavelength, includes a wavelength interval in which it is non-constant. The device further comprises a second light source (18b) which also generates polychromatic light, but to which a second spectral source function (SFb) is associated differing from the first spectral source function. An optical fiber (20) receives at one end the light generated by the light source. Imaging optics (26, 28) produces an image of the other fiber end (24) on the optical interface (12). This image is chromatically blurred along the optical axis due to chromatic longitudinal aberration of the imaging optics. A sensor (32) measures the intensity of light reflected from the optical interface (12). An evaluation unit (34) calculates the wavelength of the reflected light from the intensity measured by the sensor using the first and the second spectral source functions (SFa, SFb), and from the wavelength the distance to the optical interface. |
