Projection display system and method

A method for operating a projection display system, the method comprising:

• generating unpolarized light with a first light-emitting diode (LED);
• receiving the unpolarized light with a light guide from a perimeter of the light guide;
• guiding the received unpolarized light, as guided light, between a light emission surface of the light guide and an opposing surface of the light guide;
• directing, with a plurality of light-extraction features in or on the light guide, a portion of the guided light out of the light guide through the light emission surface as unpolarized emitted light;
• reflecting, with a polarizing film, at least some of a first polarization state of the unpolarized emitted light into the light guide through the light emission surface;
• transmitting, with the polarizing film, at least some of a second polarization state, orthogonal to the first polarization state, of the unpolarized emitted light through the polarizing film to form a polarized light beam;
• receiving, with an angular reduction film, the polarized light beam;
• reducing, with the angular reduction film, a range of propagation angles of the polarized light beam;
• modulating, with a polarization-modulating panel operating in reflection and including an array of pixels, polarization states of corresponding portions of the polarized light beam to form a polarization-modulated beam;
• and
• converting, with a polarizer comprising a beamsplitter disposed in an optical path between the angular reduction film and the polarization-modulating panel, the polarization-modulated beam to an intensity-modulated beam.

A projection display system, comprising:

• a first light-emitting diode (LED) and a second LED configured to generate unpolarized light, the first LED configured to emit light at a first wavelength, the second LED configured to emit light at a second wavelength different from the first wavelength;
• a polarizing film configured to:
• reflect at least some of a first polarization state of the unpolarized light;
• and
• transmit at least some of a second polarization state, orthogonal to the first polarization state, of the unpolarized light through the polarizing film to form a polarized light beam;
• an angular reduction film configured to receive the polarized light beam and reduce a range of propagation angles of the polarized light beam, the angular reduction film including a plurality of angular reduction film grooves;
• a polarization-modulating panel configured to operate in reflection and including an array of pixels, each pixel configured to modulate a polarization state of a corresponding portion of the polarized light beam to form a polarization-modulated beam;
• and
• a polarizer configured to convert the polarization-modulated beam to an intensity-modulated beam, the polarizer comprising a beamsplitter disposed in an optical path between the angular reduction film and the polarization-modulating panel.