54.5L: Late‐News Paper: A 24‐inch AM‐OLED Display with XGA Resolution by Novel Seamless Tiling Technology

Abstract

We developed a novel seamless tiling technology for full color AM-OLED display. This technology is based on three items: 1) TAC-based tiling structure, 2) High precision tiling process, 3) Brightness and color matching system. As a result, a 24-inch panel, the largest OLED display ever reported, has been fabricated using 2x2 tiles with no apparent seams. IntroductionIn recent years, several large screen organic light emitting diode (OLED) displays have been reported or demonstrated. These works utilize either of the following technologies: 1) small molecule OLED deposited by vacuum evaporation using shadow mask [1], 2) polymer LED deposited by ink-jet printing [2], 3) white emission small molecule OLED with color filter [3].It seems that the most important task for large screen OLED displays is how to deposit OLED materials that produce three different colors. However, high color saturation should also be cared for such large size applications as consumer television.Among the technologies stated above, the shadow mask method gives us the best color saturation. Especially, our TAC (Top emission Adaptive Current drive) technology can improve the color saturation by micro-cavity effect [1] [5], and the large color gamut, as large as that of CRT, has been realized. On the other hand, production by the shadow mask method is rather difficult especially in the case of large size display, because high accuracy is required for mask alignment over the entire display area.Tiling technology is one of the good ways to overcome this problem. We report here about our AM-OLED seamless tiling technology based on the TAC structure, as well as the performances of the fabricated 24-inch display. Seamless Tiling TechnologyOur seamless tiling technology is concluded to 3 items below. 1) TAC-based tiling structure 2) High precision tiling process 3) Brightness and color matching system TAC-Based Tiling StructureThe major requirements for invisible seams are: (1) concealing the joint gaps using opaque masks and (2) making a continuous pixel pitch across the screen including the joint regions. In addition, it is necessary to encapsulate the joint gaps preventing the OLED devices from being degraded by the atmospheric oxygen or moisture.With these requirements set to our top emitting device structure, we undertook the technological development utilizing the panel design illustrated in Figure 1.An excellent tiling technology for LCD has been reported by Rainbow Displays Inc [6], but it is quite obvious that OLED is more suited for tiling especially in terms of resolution because OLED does not require a sealing structure for encapsulating liquid crystal. In addition, the top emitting device structure is very advantageous for tiling compared with the bottom emitting structure. The bottom emitting structure has glass edges on the viewing side, so it is difficult to cover up the seams because of reflection and scattering of light at the glass edges when looked sideward.Back Encapsulation Glass Plate Front Encapsulation Glass Plate Concealing M...

An 81-in. 8 K OLED Kawara-type multidisplay with flexible displays that provides a seamless image

“…However, conventional multidisplay techniques have a substantial disadvantage in that the displayed image is discontinuous because of opaque edges at the joints between panels. However, attempts to alleviate this condition by incorporating thin edges for the joints place a limitation on the number of arranged panels because terminals must be positioned at the periphery of the display . We have solved this problem by utilizing the thinness and bendability of flexible OLED panels and fabricated an 81‐inch 8 K multidisplay using thirty‐six 13.5‐in.…”

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