Sandia has designed and prototyped a monocular for the use in a head-mounted system. The all-reflective design approach utilized freeform and aspheric surfaces to surpass the performance available from more conventional reflective designs. The prototyped design demonstrated and validated the design approach, mirror fabrication process, and alignment of the system. The system exhibited a magnification of 6.6× , a field-of-view of 4.5 deg, and an excellent image quality.
Sandia has developed an optical design for wearable binoculars utilizing freeform surfaces and switchable mirrors. The
goals of the effort included a design lightweight enough to be worn by the user while providing a useful field of view and
magnification as well as non-mechanical switching between normal and zoomed vision. Sandia’s approach is a four
mirror, off-axis system taking advantage of the weight savings and chromatic performance of a reflective system. The
system incorporates an electrochromic mirror on the final surface before the eye allowing the user to switch between
viewing modes. Results from a prototype of a monocular version with 6.6x magnification will be presented. The
individual mirrors, including three off-axis aspheres and one true freeform, were fabricated using a diamond-turning
based process. A slow-slide servo process was used for the freeform element. Surface roughness and form measurement
of the freeform mirror will be presented as well as the expected impact on performance. The alignment and assembly
procedure will be reviewed as well as the measured optical performance of the prototype. In parallel to the optical
design work, development of an electrochromic mirror has provided a working device with faster switching than current
state of the art. Switchable absorbers have been demonstrated with switching times less than 0.5 seconds. The
deposition process and characterization of these devices will be presented. Finally, details of an updated optical design
with additional freeform surfaces will be presented as well as plans for integrating the electrochromic mirror into the
Gas correlation imagers are important instruments for remotely detecting effluent emissions. However, making a
functional design for field testing is non-trivial given the range of environmental conditions the system may be operated under and the required matched imaging performance for both channels. We present a dual channel 7 degree full field of view f/2.5 athermal optical design athermalized from 0 to 50 degrees C that operates in the wavelength range of 2.0 to 2.5 microns suitable for methane imaging. We present the optical design, tolerance budget, and alignment plan used for the system. Predicted and as-built performance data including interferometric and ensquared energy measurements for both imaging channels are also shown.
Sticker shock for optomechanical hardware designed for advanced optical DEMVAL systems can lead to program loss.
In optomechanical design it is important to manage this risk through easily manufacturable and inexpensive hardware to
meet demands of lower budget programs. The optical and optomechanical design teams must work closely to optimize
system design for ease of manufacture, and assembly, while at the same time minimizing the impacts to system
performance. Effective teaming often results in unique/creative design solutions which enable future system
development. Outlined are some novel optomechanical structure concepts, with 5 degrees of freedom (DOF), used to
design a low cost DEMVAL optical system. The concepts discussed include inexpensive repeatable magnetic kinematic
mounts, flexure rings for lens preloading, simplistic drop-in lens housing designs, and adjustable tooling ball metering
rods which accommodate alignment in 5 DOF.