| 摘要 |
The invention relates to a device or system that is used to focus a lens automatically and to the application thereof in relation to methods and devices for optically testing parts. The device for focusing a lens (2) that is used to observe a substrate (4, 104, 204) comprises: a confocal optical system (13) which incorporates said observation lens and which has a longitudinal chromatic aberration in a wavelength interval; a source (12) which is adapted to emit polychromatic incident radiation (AI) having a continuous spectrum in a useful band [λ1, λ2] the wavelength of which is included in said interval; a spectrograph (14) which is adapted to deliver a spectrum of autofocus radiation (AR) reflected by the substrate and transported, in addition to said incident radiation (AI), by the confocal optical system; and movement control means (23, 26) which are used to control a relative movement (25) of the substrate and the observation lens along the optical axis (Z) of the latter, according to the difference between a central wavelength (λMAX) of a line (24) of said spectrum with maximum intensity and a reference wavelength (λREF). |
