印表機LCD控制面板之電磁相容性問題分析與改善

Abstract

為了使印表機具有視覺性的操作特性，LCD顯示器控制模組被設計成為印表機的一個操作介面。本論文主要探討這個控制模組在電磁相容性的設計及驗證中所遭遇到的問題為何? 如何分析以及找出最有效的改善對策。 由於LCD的訊號傳輸線容易形成無可避免的天線，所以印表機的控制面板在EMC的測試中，最容易發生的問題為電磁雜訊輻射及輻射耐受性。通常產品在設計的階段，除了首先完成功能性設計也要採取EMC預留設計，除了要避免產生電磁輻射之外，也要設法提高被干擾的抵抗力，因此最好也能採取預防性的EMC對策導入或預留。例如初期即導入的電路板佈線防範處理、或預先設計好對策元件的佈線及空間預留，以方便後續對策的修正及實現。 文中首先介紹電磁相容性之相關背景知識、測試設備及相關法規。接著對實際案例分析了輻射干擾與被干擾發生的來源路徑，並且針對問題的現象提出改善之對策進行實驗。

The design of printer needs control panel to have a visually operation characteristics. A combined touch function LCD display control module is designed as a printer interface. In this thesis we discussed what kind of the EMC problem will encounter in this control panel and how to analyze, debug, and study a solution to solve the issues. Because of the inevitable antenna formed by LCD signal transmission cable, the problems is most likely to occurs on printer’s control panel in EMC test are Radiated Emissions and Radiated Immunity. In the process of product design, we solve the problem of functional design, but also take preventive EMC countermeasure, except for evading the electromagnetic radiation from being produced. Also, the resistance of being interfered should try to be raised. Therefore, in the convenience of correcting and realizing the subsequent countermeasures, it’s better to take preventive EMC conductive countermeasures or reservations, such as taking action to keep the layout of circuit board that is conducted in early stages from succeeding or design the layout countermeasures and leave a space beforehand. This thesis introduced the background knowledge of electromagnetic compatibility, test equipment and related regulations. The actual case was analyzed on phenomenon, source path for radiation interface, and the interfered problem. The countermeasures are proposed for experimentation to solve the problem.