Aspheric optical design; mould tool inserts;
polymer optics and multiplexed hyperaspherical surfaces.
Uniqueness:
Hyperaspheres are independent of a conic constant and
aspheric coefficients. Standard optical software requires
pre-defined optical surfaces. In contrast Hyperaspherical surfaces
are a dynamic consequence of pre-defined wavefronts - key to
advanced (and adaptive devices) fabrication.
Free
Software: Bentec offers free software both generally and
related to specific projects regarding aspheric lens design and
manufacture of polymer optics. If you have an application in mind,
we would be delighted to illustrate the optical system with perhaps,
a view to manufacturing the optical devices related to the project.
Niche markets and highly confidential exclusive partnerships are our
interests in conjunction with the development of enabling
technologies.
Information: The programs on this web site have been written in
the Visual Basic 6 programming language and illustrate nth order
Multiplexed Hyperaspherical optical surfaces - free of a conic
constant and aspheric polynomials. These surfaces provide the
initial design process with automatic and immediate results and serve to
remove many of the complexities of aspherical surface design. The
techniques employed are unique to the optical design process and
permit nth order surfaces to roam according to initial specifications
of centre thickness, refractive index and back focal length.
Non-spherical (or spherical)
wavefronts may be imposed between surfaces. Fermat's principle
provides the glue that holds these surfaces together regarding
functionality. Any number of nth-order aspherical surfaces may be
simultaneously combined, (multiplexed), where each maintains its
relative integrity - but it is rarely necessary to
employ more than two of these surfaces within a system of standard
spheroidal or conicoidal surfaces.
Aspherization /Refurbishment): In the mid-infrared and
far-infrared it is often possible to improve performance or reduce optical elements.
Hyperaspherical lenses: Unlike
conventional spherical lenses, can refract light at large angles
without introducing spherical aberration - thus a single
hyperasphere can perform the same function as a compound lens system
- for use anywhere you might otherwise use a
microscope objective. Generally, hyperaspheres are less bulky and especially useful for coupling light to optical fiber as well as
collimating diode lasers. Hyperaspheres do not rely upon a conic
constant or pre-selected refracting surfaces and steer (or focus)
non-spherical wavefronts.
Hybrid lenses: One may improve or alter the optical function of a conventional
glass lens using a drop of UV photo polymer and moulding die. For
wavelengths between 400 and 1600nm the process is simple and
applicable where the cost of a diamond machined die is
cost-effective.
 Advantages:
Highest quality optics are achieved with lens surfaces created
by casting processes.
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Very stable manufacturing process - few, precise process
variables;
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Long life, high precision die;
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Minimum internally-induced mechanical or thermal stresses;
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Range of refractive indices;
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Excellent overall transmission - (1 to 300 µm)
polymer layer upon glass substrate;
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High homogeneity, low birefringence;
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Fresnel structure, Mirror and Grating
applications;
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Multiple optical functions may be combined;
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Correction of laser diode astigmatism using a thin cylindrical
layer on the flat side of a glass convex-plano lens;
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On Demand Cure - only cures on exposure to UV
light;
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No Solvents - 100% Solids - no mixing, no waste, no disposal of waste, no cleaning of mixing containers, no problems with pot life of mixed
materials;
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Readily adapted into existing processes; Automated Handling, Dispensing and Curing can be employed to improve production
efficiency and thus reduce costs.
Materials suitable for diamond machining:
Metals: Aluminium Alloys(1100, 2011, 2017,
2024, 5086, 5186, 6061, 7051); Copper(OFHC); Brass; Tin; Silver;
Gold; Zinc; Nickel (electroless and electrolytic plating); Magnesium
Polymers: Acrylic; Nylon; Polycarbonate;
Polystyrene; Polysulfane; Acetal; Fluoroplastic
Crystals: Germanium; Zinc
Selenide; Zinc Sulfide; Lithium Niobate; Cesium Iodide;
Potassium-Dihydrogen-Phosphate; Silicon; Potassium Bromide; Gallium
Arsenide; AMTIR
Materials Not suitable:
Ferrous metals and Optical glass both
cause graphitization - a chemical reaction in the presents of oxygen
between the diamond and carbon - which rapidly destroys the cutting
edge of the diamond tool. Monocrystalline diamond is the only
material which can provide a tool edge radius less than 50 nm and a
cutting edge without notches. The reasons for tool wear in diamond
turning of steel alloys are not fully understood. | 
