Pixel Science and Pints – Where Display Tech May Be Going

The Society for Information Display's European chapter staged its biennial Eurodisplay conference in Dublin, drawing roughly 100 industry attendees—mostly engineers and PhDs—to about 50 technical presentations over three days. The columnist, who has attended the main SID show two or three times, made the roughly five-hour flight from Halifax to compare the smaller European event with the US flagship and gauge where display technology may be heading. Eurodisplay, the column notes, is volunteer-run and built around learning rather than hands-on trade show demos. For a small business, the practical takeaway is that proven options such as COB video walls already cover most large-format indoor needs, and there is little reason to chase novelty hardware.

A smaller, volunteer-run gathering

The Society for Information Display runs a substantial annual conference and trade show on the US west coast; what appears there reflects finished display products, or their composition and manufacturing, five or more years out. The European chapter stages its own conference every second year—most recently in Grenoble, France, before Dublin—and Eurodisplay is much smaller, organized and run entirely by volunteers, including industry veteran Sam Phenix, who does LED consulting from a home office in County Down.

The agenda was steeped in research. One topic explored was inorganic halide perovskite thin films realized by pulsed laser deposition over large area for MicroLED color conversion layers, and most presentations followed similarly technical lines. A tabletop exhibit area served coffee breaks. The only display technology on show was a Barco Eonis 3D monitor—a working demo of a glasses-free, autostereoscopic display aimed at medical imaging that can also be switched to conventional 2D.

For digital signage sales and business development people, SID events are not target-rich environments full of integrators and end users; such attendees would more likely be reading emails or scouting pubs in Temple Bar. For anyone highly technical who wants to understand what is on the display technology horizon, SID events are very good. The columnist judged the trip probably not worth it given his limited technical chops and the minimal trade show component—though the Guinness, Beamish and Murphy's side research was, he says, highly beneficial.

MicroLED's production hurdles

Glasses-free 3D has been attempted many times over the past decade or two, with few gaining traction, in part because such displays were marketed on the novelty of images seemingly jumping off a flat surface—interesting once or twice, then forgettable. High-resolution medical imaging is different, carrying specific value for diagnostics and therefore a business case; anything offering more granular detail and multiple viewing angles would likely please radiologists. The columnist has seen Sony's spatial display and demos from manufacturers such as BOE, so Barco faces competition in monitors producing similar visual effects.

MicroLED came up repeatedly. The view presented was that the technology suits small displays more than large video walls: it packs an extraordinary number of tiny light emitters into a square inch, but that density matters less for displays viewed from several steps back. Chip-on-board (COB) video walls, already mass manufactured with well-established technology, are arguably more than adequate for most large-format indoor jobs. The engineering hurdles also persist. SID chair Qun Yan, a display expert and professor at a Shanghai university, used his opening talk in Dublin to walk through inspection challenges—measuring the percentage and location of dead pixels from manufacturing runs. Yield, the share of working light pixels on a module off the line, must reach the high-nines percent range; high-throughput methods can miss electrical defects at high rates, while full parametric inspection is slow and can damage light chips. Yan outlined ways to balance speed, accuracy and inspection damage using magnetic fields, plasma and stretchable electrodes.

Asian display manufacturers including TCL, AUO, Vistar and Tianma see potential for large-format video displays built from tiled MicroLED units, but in the nearer term the market may be products and components such as wearables, portable devices and wide, often curved automotive dashboards.

OLEDs are the go-to technology for wearables and handheld devices such as smartphones. Now the Dresden, Germany-based Fraunhofer Institute is promoting a full-color RGBW OLED micro-display rated at 5,040 pixels per inch, intended for wearables. For reference, a fine-pitch COB LED video wall product typically has about 28 pixels per inch. The produced unit is less than a quarter inch wide, roughly a third the size of a coffee bean.