| 摘要 |
An optical element includes a microlens array and a reflective surface. The microlens array has a focal curve and a focal length, and the reflective surface is spaced from the focal curve. When used as an exit-pupil expander, such an optical element can often generate output beamlets that have a more uniform brightness than the output beamlets generated by a diffractive optical element. Furthermore, such an optical element can define an output-beamlet envelope having an aperture that is less wavelength-dependent than the aperture of an output-beamlet envelope defined by an exit-pupil expander that incorporates a diffractive optical element. In addition, such an optical element can often produce an image having less speckle than an exit-pupil expander that incorporates a diffractive optical element when used with one or more coherent light sources.
|
