Light assembly

A projection device, comprising:

• a light assembly to emit light;
• and
• one or more microelectromechanical system (MEMS) mirrors to oscillate about at least one oscillation axis to scan the light emitted from the light assembly across a projection screen to project an image on the projection screen, the light assembly comprising:
• at least one laser source operable to emit a laser beam;
• a first part comprising a first surface, a second surface, and a third surface, the first surface, the second surface, and the third surface arranged in optical communication with each other, the first and the second surfaces arranged to form an angle of 60 degrees between them;
• a second part comprising a fourth surface, a fifth surface, and a sixth surface, the sixth surface in optical communication with the fourth and fifth surfaces, the fourth and the fifth surfaces arranged to form an angle of 120 degrees between them;
• and
• a beam splitting plate disposed between the third surface and the sixth surface, the beam splitting plate to split an incident laser beam emitted by the laser source, by reflecting a first portion of the laser beam and transmitting a second portion of the laser beam, the sixth surface to transmit the laser beam to the beam splitting plate and to transmit the second portion of the laser beam to the fifth surface, the third surface to transmit the second portion of the laser beam to the first surface,
• the first surface to define a first mirror arranged to receive the second portion of the laser beam from the beam splitting plate and reflect the second portion of the laser beam to the second surface;
• the second surface to define a second mirror arranged to receive the second portion of the laser beam from the first mirror and to direct the second portion of the laser beam to the third surface, the first and the second mirrors and the third surface arranged to define an optical path for the second portion of the laser beam with a length equal to, or greater than, a coherence length of the laser beam,
• the fourth surface to receive the laser beam and communicate the laser beam to the sixth surface, and
• the fifth surface to receive the second portion of the laser beam from the sixth surface and to receive the first portion of the laser beam from the third surface, an orientation between the first and second surface and between the fourth and fifth surfaces such that the first portion of the laser beam is transmitted through the fifth surface in parallel to the second portion of the laser beam.

A method comprising:

• receiving a light beam at a beam splitter, the beam splitter disposed between a first part and a second part, the first part comprising a first surface, a second surface, and a third surface, the second part comprising a fourth surface, a fifth surface, and a sixth surface, the beam splitter disposed between the third and sixth surfaces, the first and the second surfaces arranged to form an angle of 60 degrees between them and the fourth and the fifth surfaces arranged to form an angle of 120 degrees between them;
• splitting, at a beam splitter, the light beam into a first light beam portion and a second light beam portion;
• reflecting, via the beam splitter, the first light beam portion to the fifth surface;
• transmitting, via the beam splitter, the second light beam portion to the first surface;
• reflecting, via at least a first mirror at the first surface, the second light beam portion to the second surface;
• reflecting, via at least a second mirror at the second surface, the second light beam portion to the third surface, the first surface and the second surface to define an optical path, the optical path to have a length equal to, or greater than, a coherence length of the light beam;
• transmitting the second light beam portion through the third surface, the beam splitter and the sixth surface to the fifth surface;
• and
• emitting, from the fifth surface, the first light beam portion and the second light beam portion.