reply to post by StargateSG7
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One more December update as to the progress of the OpenStealth Project regarding
the latest progress on the use of GLASS MASTERS to imprint optical waveguides
onto BOTH flexible membrane materials (i.e. clothing) and hard plastic panels.
1) Issue #1 is the actually process of etching an optical
waveguide pattern onto a THERMALLY STABLE GLASS SUBSTRATE
using a number of different processes. Light Path Construction Software
has been a GREAT HELP in actually choosing final materials and constructing
the blueprints for the actual optical waveguide placement and routing such
that light travel distances are the same on all input/output
sides and that the modeling of incoming light reflectance,
refraction and diffraction issues are resolved.
On an actual construction basis, the current means and methods
used to press waveguides onto various hard and soft substances
has allowed us to virtually model MULTIPLE performance parameters
such that we NOW KNOW what specific technical hurdles need to
be overcome during the actual manufacturing process.
Wave Guide glass masters MUST be thermally stable and mechanically inflexible
so that final wave guide edges LINE UP PRECISELY when stamped hard-plastic
waveguide panels are glued/fused together so that the multi-frequency
light that is "ingested" into the waveguide path does not scatter at
the optical-tunnel edges/seams thus reducing or otherwise changing
the light output at the output end of the waveguide which forms
the better part of this PASSIVE optical stealth system.
2) Since I'm thinking INEXPENSIVE, there is an abstract of a paper
presented in 2005 which IS of assistance in creating the microlens
arrays used for the input and output of light waves into a PLASTIC
waveguide using etched glass masters. One key issue NOT discussed
though are the ANTI-REFLECTIVE coatings that NEED to be vapour-deposited
onto the lens arrays to assist in the preservation of the input state of
the multi-frequency light wave as it bounces off of the internal walls
of a waveguide and exits on the other side of an optical-stealth covered object.
Particular issues that arise are the properties of an anti-reflective
lens coating that allows a specified angular distance/swath of incoming
light to be gathered into the stealth panel and REJECTING light coming
in from all other angles outside of the specified angular distance.
Microlenses must be kept a specific distance apart (MINIMUM half-the
diameter of the microlens) from each other and the angular input from
the front/crown of the micro-lens SHOULD BE on a -45 Degree to +45 Degree
from the centre-point of the lens for OPTIMUM stealth and to PREVENT light
reflected off of the surface of an ADJACENT microlens being gathered for
input into the current (i.e. WRONG!) waveguide path.
Primer on Anti-reflective Coatings:
en.wikipedia.org...
See this primer on Optical Coatings:
en.wikipedia.org...
Anti-reflective lens coatings MUST also take into account
the ANGLE OF INCIDENCE when a particular TYPE of coating
is being applied to the input/exit lens arrays on optical
stealth waveguides:
en.wikipedia.org...
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Microlens fabrication using an etched glass master
P. Zhang, G. Londe, J. Sung,
E. Johnson, M. Lee, H. J. Cho
Abstract
This paper presents a micromachining technique to fabricate microlenses
using an etched glass master. The isotropic etching profile of the
glass master was utilized for microlens replication. The master was
treated by C4F8 plasma to form a conformal anti-adhesion layer.
Lens arrays were replicated on polymer substrates by hot embossing.
Microlenses with a large numerical aperture could be fabricated
with this method. This work facilitates and simplifies fabrication
steps for microlenses.
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3) The basics of ETCHING waveguides comes from the CD/DVD disc manufacturing
industry which is as outlined below:
Overview of the CD/DVD mastering of Glass Masters:
en.wikipedia.org...
Detailed Process Overview:
www.wizbit.net...
Video Overview:
www.youtube.com...
In our case, we are using an ablative laser process to etch an ENTIRE multi-beam
light path array onto two large 12" by 12" thermally STABLE and mechanically inflexible
glass panels which are then used to stamp those wave-guides onto two plastic panel
substrates which are each metallized with an optically reflective surface
ON ONLY the waveguide impressions. This is done though a charged vapour
deposition process.
Since we MUST PERFECTLY ALIGN and glue together two halves of a 180 degree
stamped circular waveguide panel impression together to form a 360-degree
"Optical Tunnel", the precision required for the alignment of the two
waveguide panels is immense. While the waveguide tunnels can be as large
a diameter a 0.2 millimetres to 0.5 millimetres to allow multi-frequency
light input/output, there is a DEFINITE technical issue with regards to
upper-lower panel waveguide impression alignment on a mechanically
consistent basis.
The seam that is created at the two-panel layer boundaries DOES HAVE
a scattering affect on light waves internally reflecting within the
walls of the waveguides but no SPECIFIC chroma (colour) shift or
Luminance (brightness) shift has yet been studied or measured with
a computerized light wave sampling system. Basic visual testing has not
yet encountered daytime human-eye visible colour fringing or blurring effects.
Both Optical-based and Infrared night vision testing of the optical
stealth panels ARE CURRENTLY FORESEEN to have a small positive sighting
on the EDGES of an optical-stealth panel covered object. (i.e. mild
blurring or fringing on object edges). The MILD nature of the edge
fringing may be acceptable due to high night vision operator
task loading who will LIKELY MISS such fringing
during active night-time operations.
Infrared emissions detection can be minimized by using 0.5mm
and larger diameter optical tunnels AND by using thermally
transmissive materials for the input/output micro lens arrays
and thermally reflective walls for the interior waveguide paths.
4) Using Hard plastic panels HAS NOT been a great technical hurdle
to overcome when using glass masters to stamp a pre-defined array of
optical waveguides onto semi-rigid plastic panels. This BODES WELL
for actual COST-EFFICIENT manufacturing at a price range less than
$5.00 per 12" by 12" panel at low-volume runs when allowing for the
manufacturing of box-like structures that have optical waveguides
that traverse around the corners and edges of a box-like structure
to the opposite side. At high volumes of 25,000 panels per run,
manufacturing costs can be as low as $2.00 U.S. per
stamped and aligned/glued two-layer 12" x 12" square
plastic optical stealth panel. Manufacturing runs in
excess of one million panels would see a dramatic
reduction to just over material and machine costs
possibly even down to less than $1.00 per panel!
edit on 2013/12/2 by StargateSG7 because: sp.