| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系 === 96 === The main objective of this thesis is to study on how to improve the color-purity of LEDs, design and develop the optical filter to apply on RGB LEDs. Using measuring equipments to measure the spectrum and check the effects of improving the color-purity of LEDs. And estimating the effects on color gamut after improving the color-purity of LEDs by check the space on the CIE chromaticity coordinates. The standard color of space that had been approved by the National Television System Committee (NTSC) is used as the reference and defined as 100%.
About the FWHM (Full Width Half Maximum) of Green light is too wide and there is mixed-zone between blue and green light in the RGB LEDs spectrum, we design green light narrow band-pass filter, mixed-zone band-stop filter and RGB narrow band-pass filter by optical design software. And we use the materials of TiO2 and SiO2 to make the filter film by thin film evaporation equipment.
From the experiment, we have found the results as following:
1. The RGB-narrow-band-pass-filter is the best one for improving the LED color purity, and the 0.4mm-glass is the best substrate.
2. The FWHM of red, green and blue light were decreasing under 17nm in axial light measurement after RGB-narrow-band-pass-filter apply on LEDs, and the range of color gamut was increasing from 118.41% to 132.56% according to NTSC standard.
3. The limitation of this study is that the filters in our experiments can not be effective for lateral light because of the light leaking from cross-section of LED chip and the different incident angle of light.
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