AVS 52nd International Symposium
    Applied Surface Science Tuesday Sessions
       Session AS+BI-TuM

Paper AS+BI-TuM5
Plasma Beam Alignment for Liquid-Crystal Displays

Tuesday, November 1, 2005, 9:40 am, Room 206

Session: Surface Characterization of Organic and Biological Systems
Presenter: Y.-F. Chang, Industrial Technology Research Institute, Taiwan
Authors: Y.-F. Chang, Industrial Technology Research Institute, Taiwan
C.-H. Lin, Industrial Technology Research Institute, Taiwan
C.-W. Chen, Industrial Technology Research Institute, Taiwan
Correspondent: Click to Email
Surface alignment of liquid crystals is an important issue in practical applications of liquid crystal (LC) cells on TFT-LCD process. The most common technique of LC alignment is an unidirectional rubbing on special polymer films which deposited on an conductive substrate such as ITO (Indium-Tin Oxide). The rubbing process has many disadvantages even though it has been widely used in the actual production of LCD. Thus, rub-free methods for LC alignment are strongly required in the next generation LCD technology. A number of non-contact LC alignment methods have been proposed in attempting to replace the rubbing process. And the well-known technique is ion beam irradiation proposed by IBM group. Another non-mechanical alignment technique, named photoalignment method, in which the UV light irradiation caused surface anisotropy of the bounding plates was studied for many years. The method was relatively simple, but the corresponding drawbacks such as weak anchoring energy as well as poor photo and thermal stability, may limit the application of this technology. In this research, a plasma beam alignment technique, in which the aligning substrate was treated with a flux of plasma that was extracted and accelerated electrostatically, was applied on the PI and diamond-like carbon (DLC) film. It is also a non-contact alignment process. The plasma flux was generated with a DC plasma source known as the anode layer thruster (ALT). The discharge channel was used to produce the sheet-like fluxes. The test panels (100 mm X 50mm) were fabricated with various plasma-beam processing parameters, w/o further passivation processes to study the alignment qualities including the pretilt angle, anchoring energy, VHR and Rdc as a function of these processing parameters. In addition, the measuring methods of these alignment qualities were also investigated in this study.