A wide-angle lens is a class of lens that we have become accustomed to using in today's world. Historically, the wide-angle lens has been the denizen of high-end, complex, bulky systems primarily because they were constructed solely of spherical glass elements. However, the wide-angle lens has become common in today's world primarily because of optical molding, both precision glass molding as well as precision plastic molding. While the nonrecurring engineering costs of these lenses is high, the resulting high-volume costs, as well as the physical size, are significantly reduced. Molded aspheres enable strong refractive surfaces while simultaneously correcting many of the troublesome aberrations resulting from spherical surfaces.
A wide angle lens designed at SMA is shown at the left. It is a wide angle, telecentric, color corrected, low distortion, all plastic, high volume design intended for use in projection of DMD imagery. It therefore has been corrected for a TIR prism in the back focal region.
This lens has been designed with the goal of achieving high performance at a very modest cost, while remaining compatible with high volume plastic molding production techniques. The design can be readily scaled to address a variety of DMD format sizes, and may be employed on-axis with a significantly enlarged image area.