The company also slashed its investment plans by $2.7 billion to 2020 citing concern for the global smartphone market.
The cut underscores the bleak outlook for electronics makers and comes a week after another Apple supplier, Taiwan Semiconductor Manufacturing Co Ltd (TSMC), also scaled back its revenue and investment estimates.
The investment cut would not impact plans to "speed up the shift" from LG's mainstay liquid crystal display (LCD) business toward next-generation organic light-emitting diode (OLED) panels, the company said.
Plans to invest about 20 trillion won in OLED panels by 2020 remained unchanged, meaning the cuts would apply mainly to LCD operations.
The company said its investment made on the 10.5-generation production line in Paju, north of Seoul, will be allocated for the OLED business.
LG Display posted an operating loss of 228 billion won ($202.1 million), hit by declining panel prices. Revenue for the April-June quarter fell 15 percent from a year earlier to 5.6 trillion won.
The company said TV panels accounted for 42 percent of its sales, followed by mobile panels with 22 percent. Laptop and table PC panels took up 19 percent, trailed by monitor panels at 17 percent.
China recently approved an LG joint venture to run a new OLED factory there, as the company tries to expand its OLED business towards Chinese TV makers.
Along with the 8.5-generation OLED production line in China, the company vowed to accelerate its penetration into the market for large-sized OLED panels.