Paper No P11: BLU Inspection Machine. (September 2013)

• Record Type: Journal Article
• Authors: Nam, Teckjin; Lee, Sukte; Geum, Sangtaek; Kim, Jongkyu; Park, Sekwang
• Is Part Of: Digest of technical papers. Volume 44(2013)Supplement 1
• Page Start: 41
• Page End: 45
• Publication Date: 2013-09
• Subjects: Information display systems -- Congresses; 621.3815422
• DOI: 10.1002/sdtp.40
• Languages: English
• ISSNs: 0097-966X

Abstract

Abstract: In liquid crystal display (LCD), the liquid crystal open and closed light to the color filter as following the circuit. LCD is passive display, so it needs light source. The outer light source is back light unit (BLU). BLU is divided into LED and CCFL based on the characteristics of lighting, but the inspection machine can detect the defects equally in BLU irrespective of LED or CCFL. This paper deals with the invention of inspection machine for BLU. The inspection machine is generally called machine vision. At manufacturing LCD, to detect defects is the one of most important parts. To make the inspection machine for BLU is to make detect machine to defects. There are four types of defects at BLU: the front particles, viewing angle defect (VAD), Mura (faint stain), and scratch. So the inspection machine must to detect four types of defects all. To detect four types of defects, it needed to much research (study) and assembly of many cameras. However, we made the inspection machine using only one camera, it also detects four types of defects. Primarily many cameras are necessary at inspection machine to detect VAD. From the results of more than 200 tests, we came to know that only three angles cameras (front, two pairs) can cover to detect all VAD, and the more, two angles cameras (two pairs cameras) can be replaced by mirror. Hence, the inspection machine using only one camera is invented to detect the defects in BLU. Patent (10‐2009‐0016934) has been applied for the important tech parts for using mirror. The inspection machine for BLU is equipped at most BLU manufacture line, it has been used effectively at manufacturing BLU company.