US Patent 7259838 Optical beam separation element, measuring apparatus and method of measuring

An optical beam separation element for a measuring apparatus includes a reflecting component with a reflecting surface and an aperture for forming an optical channel common to the transmission and the reception directions in the optical beam separation element. The reflecting surface of the reflecting component is positioned at an angle with respect to the optical channel. The aperture extends from the reflecting surface through the optical beam separation element allowing the optical beam to pass through the optical beam separation element to the optical channel in the transmission direction. The reflecting component separates the optical beams of the reception and the transmission directions.