We have reported a couple of times on the Shytech technology from Continental that is being developed for hiding the displays of vehicles under the dashboard. (A Deeper Dive into the Hidden Display in ShyTech). The displays are disguised as natural materials such as wood, leather or metal. But Continental are not alone in developing this concept.
At SID Display Week in 2022, Dr. Wan-Tsang Wang of AUO gave a talk “41.3 – A High Resolution Stretchable Micro-LED Display” that described a stretchable display based on microLEDs that can be used for the same application. Most of his talk was about stretchable displays in general and I found it useful.
Looking at the evolution of flexible displays, Wang pointed out that most flexible displays have just been made with the flex being used for ‘border curving’ in smartphones. There have been some foldable smartphones and LG has sold some rollable TVs, but what is next? He thinks that the next target is stretchable displays. Applications he has in mind are:
- Hyperboloid displays with free shapes in cars
- A-Pillar Displays in cars
- Car decoration and ‘camouflage’
- Outfacing spherical displays
- Inward spheres – for example in flight simulators
- Applications for human use and covering
(As it happens, earlier this year I was at the military training/simulation show in London and spoke to a projection specialist who said that projection was the future for ‘simulation domes’ as it had been in the past. I said I thought that microLED had potential in the application, and a few days later, I saw that AUO had showed a demonstration at Touch Taiwan! (AUO shows a new 7.9-inch reflective cholesteric LCD display prototype and a MicroLED Dome! – Display Insider subscribers only) That projection specialist has a technology shock coming.)
Developable and non-developable Displays
Wang differentiated between ‘developable’ flexible displays, which can be made from flat displays and do not change in area and non-developable surfaces which need to be made stretchable to reflect changes in area. Typically an ‘island bridge’ structure is used where devices that can’t change in area are in the ‘islands’ and the stretching is done with ‘bridges’. His paper looks at the way that if the bridges are longer, the strain on stretching is less, so serpentine wires can be used to give a longer effective length, although they can use a lot of space, so AUO is using a ‘Kirigami’ concept where the bridges effectively rotate as the area expands in higher ppi applications.
It can be harder to make OLEDs stretchable as each island has be encapsulated using TFE. Using microLED means no need to encapsulate. However, if there are too many holes (around the islands) the display can be too transparent, so you need to work on this with stretchable films.
At the Display Week show, AUO showed some stretchable samples, but, Wang said, there is a trade off between high ppi and stretchability.
Back to Automotive
Anyway, coming back to the automotive application, Dr Wang talked about the way that some companies have developed ‘knob displays’ that sit on displays and allow control of car functions rather than having lots of individual switches. (I’ll come back to that in another DD). AUO is trying to develop a knob that rises up using the flexibility of the display.
He also briefly showed a video clip of a 1920 x 720 microLED display (169ppi) that is based on an LTPS backplane and is sitting under a decorative film with transmission of more than 90%. The dashboard display was also combined with a 14.6″ rollable micro display (at the top of the dashboard in the picture). This display has 2560 x 1440 resolution (202ppi) and can be rolled to a radius of 40mm.
Another reader has pointed me to a third demonstration of this concept and I’m trying to find out more. As they say, watch this space (there might be a display hidden it :-)) (BR)
The AUO video showed two ‘behind film’ displays and a central rollable high resolution microLED.
