| 摘要 |
The invention relates to a method and arrangement for focus detection in an optical measuring apparatus, such as a microscope. The invention is most preferably applicable to focus detection for measuring biological or chemical samples or for compiling an image. The invention endeavours to provide a method and arrangement, whereby the position of a focus for an objective lens in a microscope can be measured more precisely than before. Another aim of the inventive method and arrangement is to decrease scatter-inflicted interferences in the focusing of samples with a microscope and to reduce reflected light which disturbs focus detection. The aims are accomplished with an inventive solution, in which light reflecting from a measured object is occluded with a mask (460), positioned essentially in an image plane, and in which, at a suitable distance downstream of the mask, is a detector (470) detecting the space distribution of light. According to a second aspect of the invention, the aims are achieved by a method and arrangement, wherein disturbing reflected light is eliminated by utilizing the polarization of light. |
