Plane mirrors and mirror mounts The Renishaw RLE fibre optic laser encoder uses interferometry to provide high resolution, high linearity position feedback. Fixed mirror mount An RLE system comprises an RLU laser unit, one or two RLD10 detector heads and an additional, target optic - either a plane mirror or a retroreflector, to complete the interferometer configuration. Whilst Renishaw does not manufacture mirrors, various length mirrors and corresponding mirror mounts can be supplied. This data sheet provides specification details for these mirrors and mirror mounts. Mirror selection and integration should be carried out carefully to avoid degrading the metrological advantages of the interferometer system. In the case of an X-Y stage system, mirrors can contribute to system errors through: • Surface non-uniformity (flatness), which can be minimised by using an optically flat mirror and proper mounting techniques • Thermal expansion, which can be reduced by using the correct substrate materials and mounting techniques • Misalignment, which can be avoided through careful installation Adjustable mirror mount Renishaw plane mirrors Mirrors can be ordered using the following part number: RPM10-YX-XX Y = modified for Renishaw mounts N = not modified for Renishaw mounts Optical aperture (in cm): 06 - 30, increments of 1 cm only General outline and dimensions Dimensions in mm (inches) Overall dimensions - plane mirrors: Length: L + 20 (L + 0.79) Cross section: 25 (0.98) Where L = optical aperture Plane mirror specification Reflected beam characteristics Intensity of the reflected beam Cross polarisation Mirror aperture area Local flatness Total flatness Substrate Material

Plane mirror specification (continued) Cosmetics Scratch/dig US-MIL-0-13830A 60/40 To be met by a sum of no less than 3 features within 12 mm x 3 mm area No two scratches/digs permissible within 12 mm x 3 mm area Operating environment Temperature Mirrors are vacuum compatible (down to 10-8 mbar). Mirror mounts are not vacuum compatible Relative humidity Renishaw mirror mount kit Mirror mounts can be ordered directly from Renishaw using the following part number: RAM10-SX-XX Renishaw supplies three point kinematic mounts for mirrors up to 350 mm in length with a 25 mm x 25 mm cross section that...

Mirror mount installation instructions Mirror selection and installation should be carried out carefully to avoid degrading the metrological advantages of the interferometer system. • Locate the stick mirror on the two mounts so that the ball pads on the bottom of the mirror sit in the location features on the mounts (as in Figures 3 and 4). Note: two ball pads are located at the adjustable mount end and one at the fixed mount end This section details a typical alignment procedure which can be used with Renishaw mirrors and mounts to ensure errors are minimised. Mirrored surface The following...

Renishaw plc New Mills, Wotton-under-Edge Gloucestershire  GL12 8JR United Kingdom • Visually align the mirror yaw using the yaw adjustment screw (see Figure 6) so that the return beam is in line with the centre of the alignment target aperture (mirror is perpendicular to the X-Y plane) • Visually align the mirror pitch using the adjustment screw (see Figure 6) so that the return beam goes through the centre of the alignment target aperture (mirror surface is now perpendicular to the X-Y plane) • Remove the alignment target • Finely adjust the pitch and yaw of the Y-axis mirror to maximise signal...