A federal jury in Chicago convicted a former Philips Medical Systems engineer of stealing closely guarded X-ray technology for work benefiting a Chinese competitor, adding a criminal verdict to a years-long dispute over technology used in CT scanners.
Chih-Yee Jen, 71, was found guilty after a week-long trial of conspiracy to steal, misappropriate, or possess trade secrets and of possessing or attempting to possess stolen trade secrets, the Justice Department announced on Aug. 24.
Jen worked at Philips’s facility in Aurora, Illinois, where employees researched, developed, and manufactured X-ray tubes used in computed tomography, or CT, scanners. Through its Dunlee business, Philips had spent years developing proprietary X-ray technology, according to the Justice Department.
Prosecutors said that in 2017, as Philips prepared to close the Aurora facility, China-based Kunshan GuoLi Electronic Technology Co. and its vice president, Xiaoqin Du, began communicating with Jen about creating a U.S. subsidiary that would compete with Philips in developing, manufacturing, and selling X-ray tubes.
While still at Philips, Jen shared confidential documents with GuoLi and Du, copied proprietary X-ray information from Philips databases, and recruited other Philips engineers to join the GuoLi subsidiary, prosecutors said. He later used stolen information in work developing technology for that operation.
Two other former Philips engineers, Fince Tendian and Vladimir Nevtonenko, pleaded guilty before Jen’s trial and admitted possessing stolen trade secrets. Du, GuoLi, and related Chinese company Kunshan Yiyuan Medical Technology Co. were also indicted but have not yet appeared in U.S. court to enter pleas and remain on the court’s Fugitive Calendar.
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The criminal prosecution followed civil litigation Philips began in 2019 against GL Leading Technologies, an Illinois company where some former Philips employees went to work, and later expanded to include GuoLi and Yiyuan.
Yiyuan’s current website still lists YY8019. Another product page that a February 2025 archived version identified as GLA 2153-GX now identifies the same 5.3MHU-series product as YY5323, while retaining substantially the same description and comparison with Philips Dunlee’s CTR2150 series.
The court separately awarded Philips almost $2.5 million in attorneys’ fees against GuoLi and Yiyuan.
A federal indictment filed Dec. 18, 2024, charged former Philips engineers and China-based defendants in a trade-secret case involving X-ray-tube technology. U.S. District Court for the Northern District of Illinois/Screenshot via The Epoch Times
Parallel Case in China
Philips also pursued civil claims against GuoLi and Yiyuan in China.
GuoLi disclosed that the Suzhou Intermediate People’s Court dismissed all of Philips’s claims in August 2025. Philips appealed to the Jiangsu High People’s Court in September 2025. GuoLi said the appeal remained pending when the company filed its 2025 annual report in April 2026.
The court’s full reasoning was not publicly available.
The FBI has identified efforts by the Chinese Communist Party to acquire U.S. technology and intellectual property as a major counterintelligence concern.
Federal law separately criminalizes economic espionage and commercial trade secret theft. Economic espionage requires prosecutors to prove an intended benefit to a foreign government or its agent. Jen was convicted under the separate federal trade-secret-theft statute.
Jen is scheduled to be sentenced on Jan. 5, 2027. Nevtonenko is scheduled for sentencing on Dec. 1, 2026, and Tendian on Dec. 8, 2026. GuoLi, Yiyuan, and Du have not yet appeared in U.S. court to enter pleas and remain on the court’s Fugitive Calendar.
