Compacted beam path expander, a method for expanding beam path and a large-area laser projection display system having a small compacted optical system

摘要

A beam path expander for a large-area laser projection display system having a small compacted optical system includes an incidence plane forming an anti-reflection plane to admit light having a specific wavelength into a medium without reflection, a first total reflection plane that is cut into the beam path expander at a total reflection angle determined by the refractive index of the medium for total- reflecting the light admitted from the incidence plane in the medium, a second total reflection plane that is cut into the beam path expander at a total reflection angle for total-reflecting the light reflected from the first total reflection plane at the total reflection angle in the medium, n third total reflection plane(s) (n=0, 1, 2, . . . ) cut into the beam path expander at the total reflection angle for forming a specific light path by total-reflecting the light reflected from the second total reflection plane into the medium and an outlet plane forming an anti- reflection plane to make the light which is reflected from the third total reflection plane exit from the medium. The beam path expanders are positioned between the focusing lens system and modulators and/or between the modulators and the collimating lens system in a large-area laser projection display system.