1 January 2010 Fine-pitch high-efficiency spatial optical modulator for mobile display applications
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Abstract
Diffractive spatial optical modulators (SOM) employing a fine-pitch pixel array were introduced. The micromechanical designs of the lead zirconate titanate (PZT) actuator and mirror ribbon structure were optimized for a small volume while maintaining the same level of performance. The same design rule and fabrication equipment were used for a new 10-µm-pitch and conventional 16-µm-pitch SOM. The optical efficiency of the new SOM was 78% (zeroth-order diffraction), which is an improvement over that of the 16-µm-pitch SOM (73%). The full on/off contrast ratio showed no differences, and a high displacement of 500 nm was achieved. The stress of the Pt/PZT/Pt actuating layer was the main parameter affecting the initial gap height and displacement of the ribbon. The required ribbon flatness could be achieved by applying a stress gradient on the SiN layer. The temperature-sensitive characteristics, which degrade image quality, could be minimized by a mechanical compensation method that takes advantage of the thermal expansion effect of Si substrates. The estimated lifetime of the device is >4000 h. The developed fine-pitch SOM device has sufficient response time and ribbon displacement to be suitable for high-quality embedded laser-projection displays. The VGA optical module was successfully demonstrated in a mobile laser projection display.
© (2010) Society of Photo-Optical Instrumentation Engineers (SPIE)
Jong Hyeong Song, Jong Hyeong Song, Sang Kyeong Yun, Sang Kyeong Yun, Hee-Yeoun Kim, Hee-Yeoun Kim, Seungdo An, Seungdo An, Heung-Woo Park, Heung-Woo Park, Yoon Joon Choi, Yoon Joon Choi, Victor Yurlov, Victor Yurlov, Anatoly Stepanovych Lapchuk, Anatoly Stepanovych Lapchuk, Chung Mo Yang, Chung Mo Yang, Sung Jun Lee, Sung Jun Lee, Jae Wook Jang, Jae Wook Jang, Ki Un Lee, Ki Un Lee, Ki Suk Woo, Ki Suk Woo, El Mostafa Bourim, El Mostafa Bourim, } "Fine-pitch high-efficiency spatial optical modulator for mobile display applications," Journal of Micro/Nanolithography, MEMS, and MOEMS 9(1), 013026 (1 January 2010). https://doi.org/10.1117/1.3309711 . Submission:
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