A study on UV-curable adhesive sealant for LCD panel

Abstract

With a view to suppressing the overlap shift between the TFT substrate and the color filter substrate, application of UV sealant is considered in the LCD panel assembly process. The initial tensile strength and moisture resistance of the UV sealant are evaluated and studied. In regard to the initial tensile strength, the stress applied to the sealing part during the glass cutting process, in which the peeling of the seal is most likely, is quantized by a numerical method based on the finite element method. By comparison of this result with tensile intensity tests of the UV sealant, acceptable performance is confirmed. The resistance to moisture is degraded due to large distortions on the interface between the sealant and the glass substrate, since a UV sealant hardened only by UV light has a large shrinkage on solidifying. Such shrinkage is small in a UV sealant that is hardened completely by applying heat after illumination of UV light, and hence presents practically no problem, with a moisture resistance equal to that in conventional heat curing-type sealant. From these results, the UV sealant completely hardened by applying heat after UV light illumination is found to be applicable to TFT-LCD from the point of view of tensile strength and humidity resistance. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(5): 21–27, 2000