Free space multiple laser diode module with fast axis collimator
Systems, devices, and methods for optical engines and laser projectors that are well-suited for use in wearable heads-up displays (WHUDs) are described. Generally, the optical engines of the present disclosure integrate a plurality of laser diodes (e.g., 3 laser diodes, 4 laser diodes) within a single, hermetically or partially hermetically sealed, encapsulated package. The optical engines include an optical director element that includes a curved reflective surface (e.g., parabolic cylinder) that redirects laser light beams and collimates the same along the fast axes thereof. Such optical engines may have various advantages over existing designs including, for example, smaller volumes, better manufacturability, faster modulation speed, etc. WHUDs that employ such optical engines and laser projectors are also described.
1. A method of operating an optical engine, the optical engine comprising a plurality of laser diodes hermetically or partially hermetically sealed in an encapsulated package, the method comprising:
causing the plurality of laser diodes to generate laser light;
receiving the laser light from the laser diodes by a curved reflective surface of an optical director element, wherein the shape of the curved reflective surface of the optical director element is defined by a parabolic cylinder, the parabolic cylinder including a focal line;
redirecting, by the curved reflective surface of the optical director element, the received laser light toward an optical window of the encapsulated package; and
collimating, by the curved reflective surface of the optical director element, laser light from the plurality of laser diodes along respective fast axes of the laser light,
wherein causing the plurality of laser diodes to generate laser light includes causing the plurality of laser diodes to generate laser light along an axis that is collinear with the focal line of the parabolic cylinder.
2. The method of claim 1 , further comprising:
collimating, by a plurality of collimation lenses, the laser light from the laser diodes that exits the encapsulated package via the optical window.
3. The method of claim 2 , further comprising:
combining, via a beam combiner, the plurality of laser light received from each of the collimation lenses into a single aggregate beam.
4. The method of claim 1 wherein causing the plurality of laser diodes to generate laser light comprises causing a red laser diode to generate red laser light, causing a green laser diode to generate green laser light, causing a blue laser diode to generate blue laser light, and causing an infrared laser diode to generate infrared laser light.