Nederlandse Organisatie Voor Toegepast-natuurwetenschappelijk Onderzoek Tno

Ac Optomechanix

Wimoptik B.v.

Rens Henselmans

Petrus Carolus Johannes Nicolaas Rosielle

Leonard Antonino Cacace

Willem Dirk Van Amstel

In an optical distance sensor for measuring object surfaces with high precision and comprising an objective lens for focusing a measuring beam to a measuring spot on the surfaces, measuring errors due to tilt of an object surface can be detected by using a pupil monitor, which senses the radiation intensity distribution of the reflected measuring beam effectively in the pupil of the objective lens to generate a tilt signal, which can be supplied to a correction/calibration table to obtain a correction signal, which is suitable for correcting the primary distance measuring signal of the sensor. Especially for a differential confocal distance sensor having pinholes arranged in front of radiation-sensitive detectors, a further order of correction can be obtained by determining optimum position and diameter of these pinholes.

Optical distance sensor with tilt error correction

A surface measuring apparatus for measuring a surface shape of an element includes a measurement frame having a mount for mounting the element to be measured, a stage including a rotatable device, the stage being movable in at least a first direction relative to the measurement frame, and a contactless distance measurement device for measuring in the first direction a distance between the measurement frame and a predetermined measurement surface provided on the rotatable device. The apparatus further comprises a second distance measurement device for measuring in a second direction a second distance between the device and a selected position on a surface of an element mounted relative to the measurement frame and a rotation measurement device for measuring an angle of rotation between the first and second direction. In this way, aspheric or free-form surfaces of optical elements can be measured easily in closed loop without introducing abbel-errors.

Growing community of inventors

Eindhoven, Netherlands

Rens Henselmans