Liquid crystal display cells fabricated on plastic substrate driven by low-voltage organic thin-film transistor with improved gate insulator and passivation layer
Liquid crystal display cells fabricated on plastic substrate driven by low-voltage organic thin-film transistor with improved gate insulator and passivation layer
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DOI：
10.1143/jjap.44.3728
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发表时间：
2005-06-01
期刊：
影响因子：
--
通讯作者：
Kurita, T
中科院分区：
文献类型：
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作者：
Fujisaki, Y;Sato, H;Kurita, T
在柔性塑料衬底上开发了有机薄膜晶体管驱动的5 × 5聚合物分散液晶（PDLC）显示单元。为了获得高对比度，必须提高OTFT的最大可用栅极电压。我们提出了一种由聚乙烯酚和阳极氧化的Ta(2)O(5)组成的堆叠栅绝缘体，用于降低栅漏电流并提高最大电压。具有绝缘子的OTFT显示出0.4 cm(2)/(V s)的场效应迁移率，10(5)的电流开/关比，低阈值电压为1.1 V，亚阈值斜率为0.2 V/ 10年。泄漏电流连续减小至15 V栅极电压，保持OTFT的低压工作。为了防止液晶对OTFT的降解，还提出了聚乙烯醇和光敏丙烯酸材料的双钝化层。测量了不同曲率半径下OTFT在塑料基板上的弯曲特性。OTFT可以在超过20mm的曲率半径下工作。在制作的显示电池上，我们证实了良好的显示操作，对比度为10:1，驱动电压为12-13 V。
Organic thin-film transistor (OTFT)-driven 5 x 5 polymer-dispersed liquid crystal (PDLC) display cells on a flexible plastic substrate have been developed. It is necessary to increase the maximum usable gate voltage of OTFT to obtain a high contrast ratio. We propose a stacked gate insulator that consists of polyvinylphenol and anodized Ta(2)O(5) for decreasing the gate leakage cur-rent and increase the maximum voltage. The OTFT with the insulator showed a field-effect mobility of 0.4 cm(2)/(V s), a current on/off ratio of 10(5), a low threshold voltage of 1.1 V, and a subthreshold slope of 0.2 V/decade. Leakage current was successively decreased up to a gate voltage of 15 V, maintaining a low-voltage operation of OTFT. Double passivation layers using polyvinylalcohol and photosensitive acrylic material are also proposed to prevent the degradation of OTFT by liquid crystal. The bending characteristics of OTFT on plastic substrates were also measured for various radiuses of curvature. The OTFT can operate at a radius of curvature exceeding 20 mm. On the fabricated display cells, we confirmed a good display operation with a contrast ratio of 10 : 1 with a low driving voltage of 12-13 V.