導光板壓縮模具補正對光學之影響

導光板厚度早期從1mm縮減厚度至0.5mm；成型機設備廠商也不斷研發高射出速度成型機，從早期一般射速300mm/sec以下，到高射速300mm/sec~600mm/sec，以及到目前薄化型導光板使用之 1000mm/sec之超高速成型機；但隨著產品厚度變薄，使用高速成型機雖但受限由壓力的傳遞需透過澆口至模穴末端，易造成澆口應力集中及塑品收縮厚度不均等現象，無法有效解決；本文希望藉9.7吋0.5mm實際生產開發中，由壓縮射出成型搭配不同單一條件量測光學及厚度之關係，在使用單一條件確認發現射出速度、模具溫度、以及塑料溫度影響為最大，當溫度較高時對於充填優所幫助；確認導光板厚度及光學之關係，最後利用模具設計補正，將模具模穴設計時先降低模穴厚度較深，再利用調整快做模具補正，進行可以得到較均勻之厚度及光學效果；藉由模流分析，可以得知產品壓力較大之地方都是在進澆口之位置實際量測光學數值都較高，相對較薄處光學卻都偏低，會造成整體光學均勻性不佳及暗角，利用成型參數調整有限主要受限於模具澆口位置流長比之壓力傳遞問題，及射出機台之模板平行度和模具本身之精度，以壓縮模成型確認產品厚度在規格內，但成型量測後厚度較均勻最大及最小還會有0.05mm-0.08mm之範圍，但如果利用模具之補正壓縮模成型，可以有效改善以上之問題，並可有效控制產品厚度在0.02mm以內，除了有效改善厚度，以相對提高光學之均勻性；光學模具之特點除了外型結構之外更重視光學特性，希望能藉由此研究，透過光學模具補正，可以有效克服澆口之流動造成的流動不均及光學調整之時間，縮短開發時間，開發光學產品時，預先利用模具補正之設計改善產品開發之週期及提升光學之效能。

關鍵字

背光模組；導光板；壓縮成型

並列摘要

The backlight module of the display uses CCFL as the light source. The initial product shape of the light guide plate is the same as the shape of the light guide plate. The thickness is relatively low for the forming and mold technology. However, as the electronic product is light and thin, it is convenient to carry. The display began to be used in a large amount, and the thickness of the LED itself was thinner than that of the CCFL. The thickness of the light source into the light source could be relatively reduced. From this period, the light guide plate gradually developed toward the flat plate form, and as the thickness of the LED became thinner, the relative light guide plate became more and more thin. Thin, the relative requirements for molds and molding technology are getting higher and higher, generally high-speed molding can not meet the demand; the thickness of the light guide plate is reduced from 1mm to 0.5mm in the early stage; the molding machine equipment manufacturers are also constantly developing high-speed injection molding machines, from the early stage The speed of 300mm/sec or less, the high-speed rate of 300mm/sec~600mm/sec, and the ultra-high-speed forming machine of 1000mm/sec used in the current thinned light guide plate; the mold also develops from the general mold to the compression mold, and the materials are constantly Evolution, everything is to produce light guides with thinner thickness and better uniformity of luminous efficiency; but with thinner product thickness Although the use of high-speed molding machine is limited by the pressure transmission through the gate to the end of the cavity, it is easy to cause the stress concentration of the gate and the uneven shrinkage of the plastic product, which cannot be effectively solved, and the introduction of injection compression verification production, but whether it is High-speed injection or injection compression must be transmitted to the cavity through the gate, which will inevitably result in uneven thickness of the product, which will result in uneven optical transfer compared to optical products. This paper hopes to use 9.7吋0.5mm actual production development, the relationship between optical and thickness is measured by compression injection molding with different single conditions; confirm the relationship between the thickness and optical of the light guide plate, and finally use the mold design to correct and compare the difference; Flow analysis, it can be known that the place where the product pressure is large is that the actual measurement optical value is higher at the position of the inlet gate, and the optical is relatively low at the relatively thin portion, which causes the overall optical uniformity and the vignetting angle. The limited adjustment of the molding parameters is mainly limited by the pressure transfer problem of the mold gate position flow length, the template parallelism of the injection machine and the precision of the mold itself, and the compression molding is used to confirm the product thickness within the specification, but the molding amount After the measurement, the thickness is more uniform and the maximum and minimum will be in the range of 0.05mm-0.08mm. However, if the correction compression molding is used, the above problems can be effectively improved, and the thickness of the product can be effectively controlled within 0.02mm, in addition to effective improvement. Thickness, in order to relatively improve the optical uniformity; the characteristics of the optical mold are more important than the external structure, and it is hoped that Research, through optical mold correction, can effectively overcome the uneven flow and optical adjustment time caused by the flow of the gate, shorten the development time, and develop the optical product, pre-use the mold correction design to improve the product development cycle and improve the optical performance.