車載用顯示器之軟性印刷電路板最佳結構研究

Abstract

隨著車聯網的逐步發展，車載用顯示器的功能應用已從單純的中控台汽車用導航應用與影音娛樂，更逐步增加主動式安全的功能應用，因此車載顯示器的可靠與耐久性更加重要。車載用顯示器的顯示驅動元件與顯示液晶模組間以軟性印刷電路板連接，目前現行研究軟性印刷電路板與車載用顯示器大多針對各自功能去進行探討，對於兩者結合後所產生應力問題，相關論文與期刊文獻中對軟性印刷電路板(FPC)設計與力學研究則較少研究探討。車載用顯示器隨著終端產品的應用逐漸演進為輕薄化，TFT-LCD整體的邊框 (border) 設計也跟著變窄，其中影響較大的部分是驅動積體電路(Source Driver IC)與軟性印刷電路板接合(FPC bonding)的位置，因窄邊框 (narrow border) 的設計使得軟性印刷電路板在組裝後的彎曲空間被大幅壓縮，在生產製程中可能因組裝手順不當而導致軟性印刷電路板與TFT-LCD玻璃交界處發生折傷。 車載顯示器應用需考量長時間運作的振動問題，因為長時間的振動是會導致軟性印刷電路板接腳的微傷害逐漸惡化，使得產品有潛在失效的風險，故本研究之針對FPC與TFT-LCD玻璃交界處發生折傷問題進行探討。經設計分析與實驗測試結果，雙層聚醯亞胺（Polyimide，PI）加無膠銅貼合，以UV膠固定的軟性印刷電路板結構設計，可完整的通過按壓、運輸振動，在機構彎折次數亦有優異的表現，整體產品體質得到明顯改善。此軟性印刷電路板結構與製程已於2016年加入產品設計規範。

Internet of Vehicle is reshaping the ecosystem of automotive supply chain and bringing in more opportunities for new players. Automotive display is the point of interaction and information for all the data enabled by connectivity, playing a central role in both informing and providing the means of input and control to a growing new systems and applications moving into the car. This is helping boost market growth for car displays overall. The applications of the display function of the vehicle have been from the simple car navigation console and audio/video entertainment, more gradually increase the active safety of functional applications, so the reliability and durability of automotive displays is more important. The display driving components and the liquid crystal display module are connected with the flexible printed circuit board. At present, the research on the flexible printed circuit board and the vehicle display are mostly discussed for each function, but the studies on the stress caused by the combination of driver circuit and printed circuit board (FPC) design is less. With the application of the end product gradually evolved into a thinner and smaller structure, TFT-LCD overall border design also is narrowed, which affects the larger part of the drive body circuit (Source Driver IC) and soft printed circuit in the production process. The defects of display module may be caused by improper assembly of FPC at the junction of connection. The application of the onboard display takes into account the long-term operation of the vibration problem, because the long-term vibration will lead to FPC connection pin micro-damage deteriorated, making the product has the potential risk of failure. This study focused on the defect issues of FPC at the junction of the connection. Through the design analysis and experimental test results, double layer polyimide (PI) films plus copper paste structure design with UV glue fixed FPC process can pass film pressing and transport vibration quality test. Durability of bending times also has excellent performance. The overall product quality has been significantly improved. This FPC structure and process has been joined the product design specifications in 2016.