Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 100 === White light emitting diode (WLED) generate unpolarized light. Glare makes some disadvantages in interior lighting and automobile lighting. In order to improving these problems, we developed the polarized WLED which is packaged with nano wire-grid polarizer (NWGP).
In experiment, we compared two kinds of reflective polarizer first: nano wire-grid polarizer (NWGP), and reflective polarization film (RPF). The TM transmittance of NWGP and RPF is 83% to 78%, it is not a large difference between them. For extinction ratio, NWPG is 1100, but RPF us only 21. The performance of polarization of NWGP is much better than RPF.
To packaged the NWGP with WLED, and controlled the composition and concentration of phosphor. At a constant applied current of 20 mA, the color coordinates was (0.3389,0.3324), the correlated color temperature (CCT) was 5206K, and color rendering index (CRI) was 82.73. The extinction ratio of WLED packaged with NWGP is 1100, and packaged with RPF is 20.
WLED packaged with NWGP generated polarized light, and it also had better stability of color performance at viewing different angles and temperatures than traditional WLED. It could decrease CCT and increased the stability of color shift at different viewing angles and temperatures, and reduce the yellow ring at large viewing angles. This method also enhanced the output intensity ratio at large angles, which enhanced uniformity of output intensity of WLED packaged with NWGP.
|