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| Positive Focal Length Fresnel Lens Used
As a Collector |
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| Positive Focal Length Fresnel Lens Used
As a Collimator |
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| Negative Focal Length Fresnel Lens Used
As a Diverger |
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|
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Fresnel Lenses in Rear
Projection Displays
plastic Fresnel lens positioned just before the diffusion
screen in a projection system can provide significantly superior
corner illumination, enhancing overall display luminance uniformity.
Fresnel lenses are also used within the light engine to collimate
light through the LCD panel and focus light through the projection
lens. Disadvantages include the added cost of the lenses,
ghosting, printout of the Fresnel rings and more patterns.
Birefringence is important to control polarization-sensitive
applications.
Without reduction of ghosting artifacts, Fresnel lenses will
have limited application in text-based RP systems. Ghosting
is described in some detail including how it is caused, quantified
and reduced. Efforts to reduce cost and birefringence will
all be discussed.
Microstructured Plastic Optics for Display, Lighting
& Telecommunication Applications
April 2001
Michael F. Foley
Abstract: This poster will present recent technological advances
in the field of replicated, microstructured plastic optics,
and their applications in display optics, lighting, and telecommunications.
Microstructured plastic optics are a family of components
which incorporate features such as facets, lenticles, prisms,
surface relief structures, or microlenses, to achieve some
design intent. Multiple features can be incorporated into
a single component or system, and hybridization is possible.
The poster will discuss products, materials, processes, and
applications for microstructured plastic optics. Products
described include microlens arrays, gratings, Fresnel lenses,
Moth-eye Antireflective Microstructure? and engineered surface
relief diffusive structures. Processes which will be discussed
include casting, injection molding, compression molding, embossing,
and High Precision Molding (HPM). Tradeoffs between process
fidelity, relative cost (recurring and non-recurring), and
suitability to task will be assessed. Material considerations
such as temperature stability, optical properties, and manufacturability
issues will be detailed. Finally, a number of applications
for microstructured plastic optics will be described including
several display applications (including backlit displays,
imaging screens, LCD projectors, camera displays), lighting
applications (including LED systems and waveguide based Luminaires)
and telecommunications applications (including gratings, microlenses,
and multi-function subsystems for SWDM) will be described.
Microstructured Optics for LED Applications
October 2002
Arthur Davis
Abstract: Optics for use with Light Emitting Diodes are described.
Microstructured optics are available and customizable for
a wide variety of applications. A few of these will be touched
on. A methodology of designing these optics and the photometrics
of the typical technology is overviewed.
Stage Lighting
Fresnel lenses and diffusers are currently being used in low
temperature stage lighting applications. As LEDs begin to
be incorporated into new stage lighting designs, polymer microstructured
optics, including lens arrays, collimating or diverging Fresnel
lenses, and diffusers, all become a good source for managing
the direction of the light, plus optimizing light outputs
and efficiencies.
Infrared Fresnel Lenses
These Fresnel lenses are designed specifically to transmit
light in the infrared at wavelengths between 5 and 20 microns,
with peak transmission between 9 to 12 microns. These type
of lenses are often used in applications such as non contact
thermometers, safety beams, motion activated cameras and for
development and prototype work for motion sensors. |
