Here, we present a new double-side patterned sapphire substrate methodology that improves the efficiency of gallium nitride-light emitting diodes (GaN-LEDs). The light extraction efficiency of GaN-based LEDs was analyzed through the use of a ray-tracing simulation. The extraction efficiency was simulated using patterned sapphire substrate LEDs with a variety of shapes, depths, sizes, and spacing. Through the optimal patterning of the various factors, high extraction efficiency was realized and subsequently improved upon. The thermal LED characteristics were analyzed through the use of the COMSOL general heat transfer module. The LEDs patterned on the sapphire substrate were fabricated using nano imprint lithography. We found that the output power of the double-side patterned LED was 52% greater than that of a flat LED. The thermal resistance of the double side patterned LED was 9.5 K/W less than that found for the flat LED.
An imprinted polymeric wavelength-independent coupler (WINC), which is one of the core components used in optical fiber communications and fiber-to-the-home systems, was designed with a beam propagation method. Its designed structure has the form of the Mach-Zehnder interferometer. The polymer core size of the WINC was optimized at 8×8 μm using an imprinting technique, the hot embossing process. Optical properties of the polymeric WINC were evaluated by measuring its insertion loss and transmission spectrum. The insertion loss values for channels 1 and 2 were 3.5 and 4.2 dB, respectively, and the transmission spectrum was flat over a range of 1260 to 1640 nm.
We have developed a fabrication technique for plastic optical fiber (POF) using nonlinear organic materials. The
fabrication technique is the direct core solution injection into the hole of cladding preform formed by
polymerization of cladding solution. The cladding solution was made of MMA, BBP, and BPO. The preform of
fiber was drawn into fiber following polymerization of core solution in cladding preform. We used DR1 to
control the refractive index of fiber and investigated the sensor characteristics. The sensitivity of fabricated fiber
is about 0.11 W/°C in the temperature range from 20 °C to 100 °C.
Light valve using suspended particles was invented first by Edwin H. Land. But it could not be made to large area because it was a liquid cell containing a suspension of the particles between both transparent conductive layers. For several years, so many trials have been to make a large size of light valve. Recently we could make the light valve of large size which is film type by phase separation and/or emulsification methods. In this paper, we are introducing the light valve film made by HGI.
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