P‐13.13: The Technology of Narrow Border in Mobile Display

Abstract

Thanks to new display technology development, mobile phone has been evolving from early analog phone to current smart phone. Most noticeable evidences include display evolution from digital to liquid crystal (LCD), and to more recent active‐matrix organic light‐emitting diode (AMOLED), color advancement from monochromic to full‐color, and display panel size from small‐screen to large‐screen. Besides, full‐screen has also become a new trend in mobile phone market since 2017. To meet the full‐screen display and/or to achieve the high screen‐to‐body ratio, display panel makers have come out a variety of screen design, notch, dew‐drop, hole‐punch, etc. Equally important, narrow border is another key technical requirement that will help increase the screen‐to‐body ratio, ultimately, enhancing visual experience. Technically, screen‐to‐body ratio of 90% or higher can be considered as a full‐screen. In order to meet this full‐screen display, it is necessary to reduce the bottom‐border from 4 mm to 1 mm, and leftand right‐borders from 1.2 mm to 0.5 mm, simultaneously. However, narrow border should be compatible with ESD, De‐mux circuits. This would require a width of about 1 mm in the FANOUT area. In addition, since the upper/left/right‐borders are only 0.5 mm or narrower, frit sealing may have only about 300 um in width, putting panel reliability in a great risk.In this paper, we will describe our technology route that not only can meet narrow border specification in the AMOLED display, but also can maintain the panel stability.