Possibilities for Flexible MEMS: Take Display Systems as Examples

Abstract

After the development of cathode ray tube (CRT) in the 19th century and the commercialization of television (TV) in the 1930s display devices are always one of the dream products in daily life. The revolutionary innovation from black-and-white to color display, from small size to large area, from curved surface to flat panel, and from spaceconsuming tube to short tube, all proved that the demands and distribution of display device was growing and played a critical role on civilization and industrialization. Along the popularization of personal computer, the demand of CRT put the display technology and its industry to a highly growth field for the past few decades until the late 20th century. On the other hand, with the leaping progress of research and development on liquid crystal, liquid crystal display (LCD) also attracted customers’ attention and overwhelmingly replaced CRT and suppressed CRT industry because of its light weight and thin body. Even though LCD’s starting price was high, most of customers were still switching their display device from CRT since the bulky CRTs cost more when talking about office or house rent. Similarly to CRT, researchers also spent time developing thinner, lighter, wider viewing angle, shorter response time, and larger size LCDs. As a result, LCD became a main stream not only for computer displays, but also for recreation displays such as TV. In the same time, plasma display panel (PDP), and organic light emitting diode (OLED) also found their application fields as a flat panel display device to replace the role of CRT. Unfortunately, PDP’s high resolution and fast response time come with low life time and high power dissipation. The original advantage of large size display was also gradually replaced by the up-to-date LCD produced from the 6th-8th generation glass substrate. Thus PDP market is now suppressed by LCD and PDP manufacturers are also reducing their production. Although OLED was proved to be display-capable, recently commercialized OLED’s blue color degradation still limits its application on information display. Since the demand for larger display size, wider viewing angle, and smaller body size are still growing, projection display such as back projection TVs and overhead projectors are built in parallel. Back projection TV, owing to its bulky size and low resolution, had limited applications and disappeared from market rapidly; overhead projectors, even though still find their way in the early 21th century, it was neither portable nor long lasting. Thus, how to realize a light weight, small size, and large display area comes to one end – flexible display. When display device becomes flexible, it must be light weight and portable. It must