Patent ID: 8502113
Filing Date: 2013-08-06
Classification: A61F,B23K

Abstract:
1. A method of preparing an apparatus for material processing by producing optical breakthroughs in or on an object, said apparatus comprising a variable three-dimensionally acting focus adjustment device for focusing pulsed processing laser radiation on different locations in or on the object, wherein a contact element, which is transparent for the processing laser radiation and is to be placed on the object, is mounted to the apparatus, said contact element having, on its side to be placed on the object, a contact surface and, located opposite, an entry surface for the processing laser radiation, the contact surface having a known shape; prior to processing the object, the position of the contact surface with respect to the focus adjustment device is determined by irradiation of laser radiation on the contact surface, by focusing measurement laser radiation near or on the contact surface by the variable focus adjustment device, an energy density of the focused measurement laser radiation being too low to produce an optical breakthrough, and the focus of the measurement laser radiation being adjusted in a measurement surface which intersects the expected position of the contact surface, the method comprising: a) confocally detecting radiation scattered back or reflected back from the focus of the measurement laser radiation, b) detecting a position of points of intersection between the measurement surface and the contact surface from the confocally detected radiation and the assigned setting of the variable focus adjustment device, c) repeating the confocally detecting step, if necessary, with a modified measurement surface until a determined number of points of intersection have been detected, d) determining the position of the contact surface from the position of the points of intersection and the previously known shape of the contact surface.