Development of Rolling Hot Embossing of Double-sided Microstructure on Glass for Optical Application
Date Issued
2014
Date
2014
Author(s)
Chiu, Wei-Yen
Abstract
Glass is the preferred material for quality optical devices due to its high refractive index and low color aberration. Glass also possesses high mechanical strength and chemical resistance. Surface with microstructures and sub-wavelength nanostructures futher enable light guiding or antireflection capabilities. Currently, most micro or nano structures on glass are manufactured by e-beam lithography or laser machining techniques which are expensive and time-consuming. Mold replicating process such as micro/nano hot embossing has disadvantages of discontinuous process and long cycle time. In this research, for continuous and fast production, hot rolling method for glass substrate was developed. The glass was pre-heated to glass transition temperature (Tg) before it was embossed by roller and plane molds for dual-side microstructures.
This research consists of three major parts. First, Trace Pro software was used to find out lumininous intensity of glass with different combination of v-cuts and micro-lens in surfaces. The result showed that the best module was glass with double parallel v-cut structures. This research also design an implement heating and hot rolling facility. Roller and plane Ni-molds with v-cut structures were used to emboss heated glass. The measured lumininous intensities from glass with microstructure were higher than that from bare glass. Then, Taguchi method L9 was used to investigate the significance of processing factors including speed, pressure, infrared temperature, and temperature of roller and hot plate. The results showed that speed and pressure were more important than others. Moreover, glass with dual-side v-cut microstructures was the best combination of processing parameters fabricated by rolling embossing. The lumininous intensity of the glass was 20μW/cm2 higher than that from bare glass.
In the second parts, a simple and novel method to fabricate high-temperature resistant glassy-like carbon (GC) mold with microstrutures was proposed and studied. Furan precusor was produced by casting, then GC mold was obtained after carbonization process in the inert environment. Because of the anti-adhesive property of GC, the microstructures produced by the GC mold in rolling embossing was better and more uniform than that from Ni mold.
In the last part, the glass with parallel v-cut microstructures on both sides was used as the top surface of dye-sensitized solar cell. The current density and efficiency of solar cell were 26% and 34.2%, higher than that from similar solar cell but with bare glass as the top surface.
Subjects
玻璃
熱滾壓
雙面微結構
提高光強度
Type
thesis
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