With the move to smaller pixel sizes in the longwave IR region there has been a push for shorter focal length lenses that
are smaller, cheaper and lighter and that resolve lower spatial frequencies. As a result lenses must have better correction
for both chromatic and monochromatic aberrations. This leads to the increased use of aspheres and diffractive optical
elements (kinoforms). With recent developments in the molding of chalcogenide materials these aspheres and kinoforms
are more cost effective to manufacture. Without kinoforms the axial color can be on the order of 15 μm which degrades
the performance of the lens at the Nyquist frequency. The kinoforms are now on smaller elements and are correcting
chromatic aberration which is on the order of the design wavelength. This leads to kinoform structures that do not
require large phase changes and therefore have 1.5 to just over 2 zones. The question becomes how many zones are
required to correct small amounts of chromatic aberration in the system and are they functioning as predicted by the lens
design software? We investigate both the design performance and the as-built performance of two designs that
incorporate kinoforms for the correction of axial chromatic aberration.
With the increase in demand for infrared optics for thermal applications and the use of glass molding of chalcogenide materials to support these higher volume optical designs, an investigation of changes to the optical properties of these materials is required. Typical precision glass molding requires specific thermal conditions for proper lens molding of any type of optical glass. With these conditions a change (reduction) of optical index occurs after molding of all oxide glass types and it is presumed that a similar behavior will happen with chalcogenide based materials. We will discuss the effects of a typical molding thermal cycle for use with commercially and newly developed chalcogenide materials and show results of index variation from nominally established material data.
The demand for infrared optical elements, particularly those made of chalcogenide materials, is rapidly increasing as thermal imaging becomes affordable to the consumer. The use of these materials in conjunction with established lens manufacturing techniques presents unique challenges relative to the cost sensitive nature of this new market. We explore the process from design to manufacture, and discuss the technical challenges involved. Additionally, facets of the development process including manufacturing logistics, packaging, supply chain management, and qualification are discussed.
We describe the benefits to camera system SWaP-C associated with the use of aspheric molded glasses and optical
polymers in the design and manufacture of optical components and elements. Both camera objectives and display
eyepieces, typical for night vision man-portable EO/IR systems, are explored. We discuss optical trade-offs, system
performance, and cost reductions associated with this approach in both visible and non-visible wavebands, specifically
NIR and LWIR. Example optical models are presented, studied, and traded using this approach.
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