U.S. Philips Corporation

Hendrik Renes

Jacobus P Heemskerk

Joannes Gregorius Bremer

Carel Arthur Simons

A focussing error detection system is described for determining deviations between the plane of imaging of an objective system in an optical arrangement and the radiation-reflecting surface in said system. The apparatus comprises an optical element by means of which a radiation beam coming from the radiation reflecting surface is both rendered astigmatic and separated from a radiation beam which is directed to the radiation-reflecting surface. By the use of this element the number of components of the focussing-error detection system can be minimized and a compact construction of said system can be obtained.

Optical focussing-error detection system

A device is described for determining the linear displacement of a machine tool component with the aid of a grating which is mechanically connected to the component, which grating is disposed in the light path between a light source and a light-sensitive element which converts the incident light into an electric signal. The light-sensitive element is a multiple photo-cell which consists of a row of line-shaped photo-diodes which by means of an electrical switch are consecutively connected to an electronic circuit which processes the signal which is produced in the photo-diodes.

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Eindhoven, Netherlands

Hendrik Renes