Abstract
This publication documents the history of steering mirrors in follow spot and performer-tracking systems from 1920 to 2010 and discloses variants. A steering mirror (moving mirror, mirror head or mirror attachment) turns the beam of a stationary follow spot or other luminaire, so that only a light, low-inertia part moves: the beam responds faster, lags less behind the performer, moves steadily, and fewer parts move. Dated patents, trade press and manuals trace gimbal-mounted mirrors in front of a spotlight lens operated by hand, cords and motors from 1920; remote mirror follow spots such as the Telescan and the Pan Can; a NASA patent of 1975 in which a computer steers a servo mirror toward a transmitter worn by the performer; a mirror rotated about the optical axis of an entertainment light (coaxial) claimed in 1988; and moving-mirror luminaires (scanners) aimed from stage coordinates or from tracked transponder positions by the Wybron AutoPilot (1992–1995), the Martin Lighting Director (1997), grandMA 3D (2006), zactrack (2009) and at EXPO 2010. Drawings from expired patents illustrate the record. The disclosed variants cover coaxial and offset pan axes, gimbal and turret mounts, retrofit mirror attachments, galvanometer and MEMS drives, aiming from camera, tag or PosiStageNet position data, aim computation from the mirror centre, calibration, compensation of image rotation, several mirrors, sources and targets, zones, and control of cameras and other media.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Honold, Michel and Hermann, Paul, "Steering Mirrors in Follow Spot and Performer-Tracking Systems: A Documented History, 1920–2010, and a Disclosure of Variants", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/12419