Abstract: The present invention relates to optical components for reversing and inverting images, and to methods of manufacturing them accurately, robustly and cost-effectively. The method includes optical contact bonding a first optical element and a second optical element and adhesively bonding the first optical element and the second optical element. Adhesively bonding might include forming a notch into the second optical element and depositing a bead of adhesive into the notch, such that the adhesive adheres to both the notch and the first optical element.

Abstract: The present invention provides a way to measure the position of an instrument that is mounted on an instrument shaft within a clutched mounting system, the instrument shaft being driven through a reduction gearbox by a motor shaft. The position of the instrument is measured as a function of the position of the motor shaft and the position of the instrument shaft, the measurement of the position of the motor shaft providing greater precision than the position of the instrument shaft. Because the mounting system is clutched, it is necessary to check at intervals whether the measurement of the motor shaft position no longer accurately represents the position of the instrument, in which case the measurement of the motor shaft position is resynchronized to the measurement of the instrument shaft.