| 摘要 |
In prior art object position detectors using a radiation source 32, a beam-splitting prism 30 and a radiation sensitive detection system 34, 35 to detect the position of an object 10 relative to a base, the detector components have been positioned on the object and base so that electrical leads must be taken to both object and base. Alternatively a large and heavy auxiliary mirror was mounted on the object. In the invention, only the prism 30 is mounted on the object 10 and it can be small and light. Each detector 34 and 35, of the detection system is divided into two sub-detectors 36, 37 and 38, 39, the outputs of which are combined in two ways 51, 52, 53, 54 to provide two outputs Sy and Sxr giving translation and angular position error signals which can be fed to electromagnetic actuators to correct the object position. |
