| Summary: | 碩士 === 明新科技大學 === 電子工程系碩士在職專班 === 104 === Abstract
Interferometric Modulator Display (IMOD) is extremely efficient because they don’t emit light—they reflect it. Microscopic mirrors in each pixel change the size of an air gap inside the display. Depending on the size of the gap, white light is reflected back as red, green, or blue. [1] IMOD element is the core structure of Mirasol display technology, including two steady states. The membrane is held in the open state by applying a voltage Vbias. By applying a short write voltage pulse, the membrane will collapse and stay in that state as the voltage returns to Vbias levels. In order to return to the open state, a short negative unwritten pulse (V-unwritten) is applied, causing the membrane to snap back into the open state. [2][3] The bistability of mirasol displays comes from the inherent hysteresis derived from the technology’s electro-mechanical properties. More specifically, it derives from an inherent imbalance between the linear restorative forces of the mechanical membrane and the non-linear forces of the applied electric field. [7] The electricity consumption of LCD screen accounts for 50% of the total electricity consumption of a mobile phone, whereas IMOD screen only accounts for 6%, which means, phones with IMOD can use longer after per charge, even if you count the auxiliary light source used in the dark. [4] IMOD pixels are capable of switching speeds on the order of 10 microseconds. An IMOD element’s switching time is 1000 times faster than LCD displays. This feature makes it far more suitable for playing videos than the LCD. In addition, IMOD panels are at least as durable as LCD. According to the test of Qualcomm, IMOD element have demonstrated reliability over 12 billion cycles of switching, which means it can be used for more than seven years in a row without damages. [5]
IMOD ,unlike LCD, doesn’t get the ITO layer and Passivation as the protective layer against scratching during the manufacturing process of laminated thin film, which makes it vulnerable for scratching and scraping when its circuit area is touched. What is more, in the follow-up process, IMOD panels are handled purely by manual operation, which can easily cause scratches because of hands’ touch in the circuit area. The scrap rate of panels due to this is up to 13%. Based on this situation, we take some protective measures in this experiment to solve this problem.
Instead of using hands, we use a vacuum suction pen to fetch and drop the panel during the production process and then place the panel under a protective cover. The vacuum suction pen is a T-shape grip with suction points on both ends that can absorb the panel at a fixed point without touching the circuit area. Moreover, the protective cover can enclose the circuit area of the panel so as to prevent scrap-leading scratches. Firstly, during the panel cutting process, a large 730 mm * 920 mm panel is cut into smaller 5.1-inch panels, which are then put into a protective cover by using a vacuum suction pen. Next is to deliver the panel with protective covers to Panel Test Station and then remove the protective cover so that the panel can accept terminal inspection. All these protective measures successfully reduce the defective rate from 13% to below 2%, and improve yield by 11%, which greatly improve the profitability of the company.
Key words: Hysteresis; IMOD; Thin Film; Mirasol; Panel.
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