TCL has accused Samsung of fraud for marketing budget LCD televisions as Mini LED sets lacking the backlight technology the label implies, in a lawsuit filed in federal court in California, Ars Technica reported on Friday.

The suit, filed in late August in the U.S. District Court for the Central District of California, targets Samsung’s M70H, M80H and M90H televisions, which sell from $300 for a 43-inch model to $2,300 for a 100-inch one. The M models are “merely recycled… pre-existing, low-end, standard LED televisions” from Samsung’s entry-level Crystal UHD line, “re-labelled… as ‘Mini LED,’” the complaint says, and “contain none of the technological advancements associated with Mini LED technology, including [full array local dimming].”

Samsung did not answer questions about specific claims in the suit, according to Ars Technica, whose reporters sought comment. A spokesperson said in a statement that the company intends to vigorously defend against the lawsuit.

The case turns on what Mini LED means. The most advanced LCD backlighting, known as full array local dimming, or FALD, uses dozens to thousands of small LEDs grouped into zones whose brightness can be controlled individually, boosting contrast — the difference that makes HDR picture quality work. TCL argues the M-series sets have no such capability.

Samsung’s product pages for the sets list a feature called “Supreme Mini LED Dimming.” Spec sheets available on the same pages carry a footnote: “Supreme Mini LED Dimming is Software-based (not full-array hardware-based) technology.” With software-based dimming, a TV analyzes each frame and adjusts its brightness to improve perceived contrast, but the panel’s actual brightness stays uniform across the screen.

Software dimming “will never be as effective as a well-designed, hardware-based local dimming solution, especially in scenes that are more susceptible to blooming artifacts,” Guillaume Chansin, associate director of displays at Counterpoint Research, told Ars Technica, though he said software can help brands squeeze comparable image quality from fewer LEDs or zones.

Two other analysts went further, saying a panel without FALD should not carry the Mini LED name at all. “I think that is broadly agreed across the industry that FALD is a key and mandatory feature in Mini LED backlights,” Eric Virey, principal displays analyst at Yole Intelligence, said in an email. Bob O’Brien, Counterpoint’s research director, said Mini LED “was originally introduced as an improved FALD technology, with more dimming zones,” adding that no body has authority to set standards, leaving brands room to “be more creative in their marketing.” Even Samsung’s own website describes Mini LED as a technique “where backlight zones are controlled independently.”

TCL says it disassembled an M70H and an M80H and found they cannot perform local dimming: the sets lack the necessary LED control chip and circuitry and use the same processor as Samsung’s entry-level Crystal TVs. The complaint also says the M-series LEDs measure 0.5 mm, against the 0.1 to 0.3 mm that TCL says generally defines a Mini LED, and that the sets carry only a few dozen LEDs “arranged on two aluminum strips” rather than the thousands found in some Mini LED displays. A teardown video by the YouTube channel AP Tech shows two rows of LEDs.

Performance testing gives shoppers their own answer. The review site RTINGS measured the M80H’s contrast at 6,440:1, finding that “dark scenes look washed out in a dark room.” Samsung’s $1,200 Neo QLED QN80H, a Mini LED set with individually addressable zones — a model TCL accepts as genuine — reached 80,000:1 after calibration in the same testing.

Mr. Virey, for one, called TCL’s claims legitimate and a question for the whole industry. He is doubtful it will end with formal standards, though: creating them, he said, would produce “an endless race,” because “each time there are new technologies, new marketing terms are invented and can easily be abused.”