A year ago, at CES 2017, Samsung introduced its Q Series of super-premium quantum-dot-enhanced LCD-TVs. The company called the quantum-dot technology used in this series QLED, and gave the sets prices that were comparable to LG’s equivalent (in screen size and features) OLED sets..
Analysts, including this one, were enthusiastic, but Samsung had set a high bar for itself because, by pricing Q Series sets comparably to OLED-TVs it was sayiing that the picture quality was comparable, too. Over the following weeks and months it became clear that in at least one important way, that was not true.
In striving for sets of nearly OLED-like thinness, which Samsung believed was essential for super-premium hang-on-the-wall TVs, the company used edge lighting. This limited the sets to local dimming using a small number of large, stripe-shipped zones. When bright images were shown against dark backgrounds, this had the effect of raising the dark levels in the zones containing the bright images. This “halo effect,” which involved a reduction of the local contrast ratio, could be very noticeable with certain kinds of program material. Unfortunately for Samsung, this kind of programming occurs frequently.
LG and LG Display lost no time in demonstrating the relative performance of the QLED sets and LG’s OLED sets. (A New QLED Artifact in Paju)
The Empire Strikes Back!
At CES 2018, Samsung struck back. At two analyst/media-only events Samsung showed the 2018 high-end Q technology side-by-side with both its 2017 set and an LG OLED set. With the program material used by Samsung, the halo effect was dramatically reduced on the set using 2018 technology, and images looked comparable to those on the OLED TVs. (I think a number looked better at higher brightnesses – Man. Ed.)
The 2018 QLED screen is on the left; the 2017 OLED screen is on the right. The QLED has a significantly higher peak luminance. The OLED has a slightly darker black level, which may not be visible as you view these photos on your monitor. Is there any halo effect on the QLED screen? (Photo: Ken Werner – click for higher resolution)
So what has Samsung done? The company has replaced the edgelight of 2017 with full-matrix backlight that will have between 100 and 500 dimming zones in the production version. Samsung has also modified the optical stack and reduced the black level. Which of the Q Series models will incorporate these changes for 2018 has not yet been determined. The 2018 full-matrix set is only slightly thicker than the 2017 edgelit set, said Dennis Choi, Senior Engineer in Samsung Electronics’ R&D Team for the Visual Display Business.
Samsung also showed an 8K technology demonstration with 10,000 dimming zones, which produced a remarkable combination of adjacent bright and dark areas for an LCD.
Samsung had much more to talk about, but I want to keep this simple. LG was hurting Samsung by letting us all know about the halo effect. Now, Samsung has struck back. – Ken Werner
Ken Werner is Principal of Nutmeg Consultants, specializing in the display industry, manufacturing, technology, and applications, including mobile devices, automotive, and television. He consults for attorneys, investment analysts, and companies re-positioning themselves within the display industry or using displays in their products. He is the 2017 recipient of the Society for Information Display’s Lewis and Beatrice Winner Award. You can reach him at [email protected].
