P‐71: Analysis of Bright, Vertical, Chain‐Like Spot Occurrence on Mobile OLED Screen Due to the Electromagnetic Interference of Nearby GSM Device

• Published in: SID International Symposium Digest of technical papers Vol. 55; no. 1; pp. 1656 - 1659
• Main Authors: Chung, Chelho, Shin, Min Chul, Ha, Jihoon, Roh, Gilsung, Kim, Heejung, Kim, Haejo, Kim, Sangkyung, Yang, Jinseok
• Format: Journal Article
• Language: English
• Published: Campbell Wiley Subscription Services, Inc 01.06.2024
• Subjects: Direct current; Direct Current (DC) offset; Display devices; Display Driver Integrated Circuit (DDIC); Electromagnetic interference; Electromagnetic Interference (EMI); Electromagnetic susceptibility (EMS); Image degradation; Image quality; Integrated circuits; local brightness drift; Operational amplifiers; Organic light emitting diodes; parasitic diodes; Photodegradation; Radio frequency
• ISSN: 0097-966X; 2168-0159
• DOI: 10.1002/sdtp.17884

Electromagnetic Interference (EMI) plays a significant role on degraded image quality under specific operating conditions. During our product characterizations, we analyzed an event that shows bright vertical chain‐like spots on mobile Organic Light‐emitting Diode (OLED) display due to the transmit operation of Global System for Mobile (GSM) phone nearby the device under test (DUT). The cause of the event is laid out as follows. The transmitted Radio Frequency (RF) power travels through Flexible Printed Circuit (FPC) to Display Driver Integrated Circuit (DDIC). Then the transistors respond to RF power as unintended RF diodes, which generate unexpected Direct Current (DC) voltage, which pushes the panel‐driving buffer Operational Amplifier's (OPAMP) output drifted.