Display industry has become one of the most important industrial areas due to a rapid development of a multimedia which plays an influential role as an interface to exchange information between men and electronic devices. Recently, the demand on a thin, light, wide and low-power consumptive flat panel display (FPD) is increasing in the display market instead of the cathode ray tube (CRT) due to the start of digital broadcasting and the rapid growth of personal computer markets.
The PDP (plasma display panel) is thin, light, easy to widen, which is driven digitally as well as it has a wide angle of view among FPDs. Owing to the price reduction and the improvement in technological stability of PDP, PDP widened its market. However, still much more remains to be solved about how to improve its efficiency. Particularly, from the viewpoint of its structure, it is important to change the structure of the barrier rib in PDP in order to increase the coating space of phosphors and enlarge the discharge space for highly efficient PDP. Recently new designs of semi-closed type or closed type of discharge cells such as rectangular, SDR (Segmented electrode in Delta color arrayed Rectangular sub pixel), HEXA (High-Efficiency heXagonal Array structure) have been introduced to improve the efficiency of PDP.
The forming process of a barrier rib is one of the most important processes in manufacturing the rear panel of PDP. The barrier rib of PDP is generally manufactured by the sandblasting process. This process has several steps such as printing the paste by the table coater, formation of the protective layer, sandblasting and firing of the barrier rib. But it is not easy to manufacture a barrier rib less than 50μm in width. Therefore, a simpler process enables the manufacture of the barrier rib with closed-cell type for the high definition TV (HDTV).
In this study, the barrier ribs for the highly efficient HDTV such as rectangular, SDR and HEXA which are closed-cell type are manufactured using the roll forming process. The roll forming process is proposed as a new forming system. The roll forming process consists of the following steps: putting release agent on the mold, positioning green sheet on the mold, filling up green sheet in the mold by using a roller, attaching the green sheet on the substrate after separating the green sheet from the mold and firing the barrier rib. The finite element method (FEM) is used to optimize the process parameters such as the stroke, the angular velocity, the size and the path of the roll. The optimum process parameters are then obtained experimentally for stroke, load, angular velocity and also path of the roll. The barrier ribs such as rectangular, SDR and HEXA with 40㎛in width have been manufactured after the determined optimum parameters.
PDP의 격벽은 화소를 정의하고, 인접 셀들과 전기· 광학적 혼색(cross-talk)을 방지하며, 형광체가 코팅될 수 있는 공간을 제공 한다. 최근에 PDP의 구조적인 측면에서 고효율, 고화질화, 저가격화를 위한 연구가 진행되고 있다. 특히 스트라이프(stripe) 형상을 가진 격벽을 단점을 보완하기 위하여 닫힌 구조(closed-type)의 새로운 방전 셀을 개발하여 형광체의 도포면적을 넓히고, 방전공간을 크게 하여 효율을 향상시키기 위한 많은 연구가 진행되고 있다. 본 연구에서는 롤 성형을 이용한 새로운 격벽제작 공정을 제안하였다. 공정변수의 영향력을 예측하기 위하여 유한요소해석을 통하여 롤의 압하량, 롤의 각속도, 롤의 크기 및 경로에 대한 공정변수의 영향력을 검토하였다. 또 실험을 통하여 롤의 압하량, 롤의 각속도, 롤의 경로에 대한 공정변수를 최적화한 후, 직사각형 구조(rectangle), SDR, HEXA와 같은 닫힌 구조의 셀을 제작하였다.
