Abstract: In a light beam scanning system in which an electro-mechanical scanner is utilized to provide horizontal scan of an intensity modulated beam, alternate horizontal lines are reversed in the time domain, so that both forward and return motions of the scanning mechanism can be used in the display. The line reversal can be effected by a scan converter mechanism, and nonlinearities in the scanning mechanism can be compensated for by reading out signals during the linear part of the motion or varying the time rate at which the signals are read out.

Abstract: A laser beam comprising at least two different wavelength components is directed to be incident upon an acousto-optical modulator which is excited with acoustical waves having selected acoustic frequency to optical wavelength relationships such that collinear modulated light beams are transmitted. The system is further arranged such that the modulator functions optically in a video bandpass filter mode, to diffract the collinear color components at maximum intensity and substantially free from mutual interference. Systems are also disclosed in which the thus modulated beam is scanned and display energy is directed for maximum light output efficiency.

Abstract: A large screen display system for video modulated collimated light provides superior contrast and brightness, in a shallow depth configuration if desired. A single modulated laser beam which may have different color components is raster scanned, defining a beam envelope which is then expanded along an adequately long optical path length within a confined volume and directed toward a display screen on which the beam impinges. The optical system may selectively redirect the available light energy into a viewing volume with optical gain and with high contrast. In a particularly compact example of a rear projection system, the optical path is defined by successive reflecting elements adjacent and substantially coextensive with the screen, which cause the beam path to traverse behind the screen in successive path segments. The beam envelope is then directed obliquely against the display plane, but differentially redirected so as to be transmitted orthogonally outwardly.