應用實驗設計方法降低觸控及液晶面板全平面貼合之氣泡不良率-以C公司為例

Abstract

觸控面板(Touch panel)產業近幾年來已朝更輕更薄、成本需求等趨勢來發展。不僅提供各種嵌入式觸控方案、導入新的ITO(Indium Tin Oxide ; 氧化銦錫)替代性材料，也開始以全貼合方式來生產觸控面板。其中，又以貼合技術的優劣影響最顯著，不僅影響生產良率，也會影響手機、平板的畫面表現。

全平面貼合(Direct Bonding)是為因應現今智慧行動裝置所開發的觸控及液晶面板黏貼方式，架構是將液晶面板與觸控面板進行全平面貼合製程，利用光學膠填補液晶面板與觸控面板間之空氣層能直接增加背光光線穿透率，其利用折射率調整來降低反射，若不是整面貼膠 只要經過空氣層折射率差異過大會使反射光增加造成穿透率下降。

全貼合技術具備較佳的顯示效果，目前主要有OCR(Optical Clear Resin)液態透明膠和OCA(Optical Clear Adhesive)固態透明膠兩種光學膠為業界主要使用方案，面板10吋以下OCA為主，10~15吋以上OCR為主，由於全平面貼合含有光學膠其成本也相對提高不少,控管成本中其中最為關鍵是生產良率，且面積越大良率越低，在眾多不良項目中，最令公司頭痛的部分莫過於貼合後產生氣泡。本公司所採用是OCR製程且公司內部為了氣泡改善投入不少人力及心力，為了讓氣泡改善能更進一步，本研究透過實驗設計法(Design of Experiment，DOE)，找出OCR製程氣泡不良的主要因子進行實驗，求出製程最佳生產參數，改善氣泡不良的問題。研究中除了改善不良率以外，還能減少氣泡不良所產生的重工報廢問題。

Touch Panel industry in recent years has been towards thinner and lighter, cost demand trend to develop. Not only offers a variety of embedded touch solutions, introducing new alternative materials ITO (Indium Tin Oxide) can also start with direct bonding to produce touch panel. Among these, the most significant impact of the pros and cons bonding technology, not only affects production yields, will also affect the performance of the screen phone, tablet.

Direct bonding response to today's wisdom mobile devices which be developed touch and LCD panel adhesive way, architecture is to do direct bonding process for the LCD panel and touch panel, and using optical glue to fill the LCD panel and touch panel an air layer can directly increase the backlight light transmittance, and refractive index adjustment in oder to reduce reflection. If not paste the entire surface of the glue layer but light through the air gap, as long as the refractive index difference over too much which will make the penetration of the reflected light decreases.

Direct bonding technology has a better display effect, there are OCR(Optical Clear Resin) and OCA (Optical Clear Adhesive) two optical glue which is the main use of the program in the field.LCD panel below 10 inches which is using OCA, 10 to 15 inches which is using OCR .Due to direct bonding contain an optical bonding glue which cost is relatively improve a lot, the key point of cost control is production yields which is bigger dimension have a lower yield.Among many defect item, the most difficult part of the company is bubble after direct bonding.The company uses an OCR process and put a lot of manpower to improve bubble. In further, in order to improved bubble, this study through design of experiment to identify factor of bubble in OCR process, then find out optimum production process parameters to improve bubble problem.In addition to improve the defect rate this study, but also reduce scraped of products which come from rework of bubble.