What They Say
DSCC has followed up a report by the Korean ET News that explain that Samsung is adopting a concept of polariser-less displays, called POL-LESS OLEDs (the terms On Cell Polarizers (OCP) and Color On Encapsulation (COE) have been used to describe this technique by others).
The firm suggests that a reduction of 20% in thickness as well as an improvement in brightness can be achieved by eliminating the polarisers and using a very thin colour filter (of less than 5µm).
DSCC has found out that the change involves three key technologies:
- A black rather than transparent Pixel Definition Layer (PDL)/bank layer. This was previously not disclosed, so is something new which could play an important role in closing reflectivity performance with polarizers;
- A newly added color filter;
- A newly added black matrix.
The PDL layer helps to stop light leakage between the different colours. The colour filter is expected to be the key technology for reducing reflections (the key function of the polariser). It will make manufacturing more complex (with details in the blog), but the combination of POL-LES could increase brightness by 20% to 30% and combining it with LTPO could reduce power consumption by up to 30%.
The technology is likely to be used first on foldable devices where the reduced thickness really helps.
The ET News article also reported that an under display camera would be used for the Galaxy Fold 3 and S-Pen developments (previous Fold devices have not been strong enough to resist impact from a pen) and DSCC has more background on this.
What We Think
Sigmaintell also highlighted POL-LESS concepts as important in its SID China talk a couple of weeks ago. (Where We’re At in Smartphones) The alternative to getting rid of the polariser is to somehow ensure that the light generated by the OLED is already polarised. We have reported on several R&D projects in this area. The Samsung approach looks like a good one, but as DSCC points out, there are more processes. A key point is that those processes are performed by the panel maker, rather than money going out to polariser makers. Panel makers are always looking for ways to ‘capture the value’ rather than buying materials from outside. However, if the production of polarised light was simpler or cheaper, it might allow a change back to using polarisers. (BR)
