Browsing by Author "Chen, Alexander"

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Effects of localized warpage and stress on chip-on-glass packaging: Induced light-leakage phenomenon in mid-sized TFT-LCD
(2012-01-01)
Leu, Jihperng
;
Chang, Chin-Cheng
;
Chen, Alexander
;
Lin, Mao-Hsing
;
Huang, Kun-Feng
Mura defects become visible in a 13.3-in. TFT-LCD using chip-on-glass (COG) packaging when the thickness of the glass substrate is decreased from 0.5 to 0.3 mm. Mura, the non-uniform brightness in LCDs, is caused by COG packaging due to the mismatch of the coefficient of thermal expansion (CTE) and Young's modulus between the glass substrate and the IC-driver Si chips. In this paper, a 3-D finite-element-analysis (FEA) model, coupled with transient thermal analysis is first established to examine the warpage and stress behavior in the upper-glass-plate post-COG-package processing for identifying the root causes of the light-leakage phenomenon. Prior to that, the simulated warpage results are validated by surface-contour measurement. Data and modeling results show that a low bonding temperature together with a low modulus in novel ACF materials can effectively eliminate Mura. Besides, thinner silicon or a shorter length of Si chips as drivers offers enhanced reduction in the localized warpage, and thus can be a practical and low-cost solution for eliminating mura defects.
Effects of thermomechanical properties of polarizer components on light leakage in thin-film transistor liquid-crystal displays
(2015-07-01)
Lin, Taiy-In
;
Chen, Alexander
;
Chen, Shou-I
;
Leu, Jihperng
;
材料科學與工程學系
In this paper, we present static thermal analysis of stress and strain on a thin-film transistor liquid-crystal display (TFT-LCD) panel and their correlation with light leakage phenomena under high-temperature durability test. Three-dimensional (3D) finite element analysis (FEA) is coupled with experimental parameters of key components of the TFT-LCD panel for the analysis. A strong correlation exists between light leakage and retardation difference induced by stress on triacetyl cellulose (TAC) films. Moreover, shrinkage in stretched poly(vinyl alcohol) (PVA) film and modulus of the adhesive layer are key factors affecting stress distribution and displacement of polarizer stack. An increase in Young\'s modulus (E) of the adhesive layer effectively reduces polarizer shrinkage and light leakage at the center of the panel. A TAC film with lower Young\'s modulus and/or coefficient of thermal expansion (CTE) is also an effective solution. (C) 2015 The Japan Society of Applied Physics