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
system.
High-precision opto-mechanical structures have historically been plagued by high costs for both hardware and the
associated alignment and assembly process. This problem is especially true for space applications where only a few
production units are produced. A methodology for optical alignment and optical structure design is presented which
shifts the mechanism of maintaining precision from tightly toleranced, machined flight hardware to reusable, modular
tooling. Using the proposed methodology, optical alignment error sources are reduced by the direct alignment of optics
through their surface retroreflections (pips) as seen through a theodolite. Optical alignment adjustments are actualized
through motorized, sub-micron precision actuators in 5 degrees of freedom. Optical structure hardware costs are
reduced through the use of simple shapes (tubes, plates) and repeated components. This approach produces significantly
cheaper hardware and more efficient assembly without sacrificing alignment precision or optical structure stability. The
design, alignment plan and assembly of a 4" aperture, carbon fiber composite, Schmidt-Cassegrain concept telescope is
presented.
The Gemini Laser Launch Telescope will reside behind the secondary support structure of the Gemini 8m telescope, where it will expand an incoming sodium laser beam to 450 mm diameter and launch it into the sky, co-axial to the main telescope. The tight space and stringent performance specifications have required some innovative approaches in optical and mechanical design.
Segmented mirror telescopes take advantage of modular design to achieve large apertures at low cost. This paper describes the segment mount developed for the Southern African Large Telescope. The mount provides passive precision support for the optics, kinematic registration to the primary mirror truss, precision tip-tilt and piston adjustments, and interchangeability between segments and mounts. A trial production run of mounts is now in fabrication prior to full production of 91 units needed to populate the SALT primary.
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