| 摘要 |
<p>A system for dampening vibratory motion of a pendulous compensator (18) in a laser projector (10) includes a beam splitter (32) which diverts a portion of a laser beam deflected by a mirror mounted on a cantilever beam (22) of the compensator (18), and a photocell device (34) having a pair of photodetectors (44, 46) positioned to receive the diverted laser beam portion (42) and sense oppositely varying proportions thereof corresponding to the displacement of the position of the deflected laser beam (26). Two output signals are produced corresponding in magnitudes to the respective proportions of the diverted laser beam portion (42) sensed by the photodetectors (44, 46). A difference amplifier (40) takes the difference of these output signals to produce a first electrical signal having a polarity and magnitude representing the direction and amount of motion of the cantilever beam (22). A derivative circuit (48) takes the derivative of the first electrical signal with respect to time to produce a second electrical signal having a polarity and magnitude representing the direction and rate of movement of the cantilever beam (22). An electrical coil (52), having a magnet (54) reciprocally movable relative thereto which is linked to the cantilever beam (22), produces a magnetic force related in polarity and magnitude to the second signal to cause the magnet to resist the vibratory movement of the cantilever beam (22).</p> |
