OLED technology is in fashion. not just every time more manufacturers bet on itif not that their sales numbers are impressive and do not stop growing year after year, with some more than interesting forecasts for the future. In any case, the important fact is that all manufacturers are committed to this technology, in one way or another. And they all have a common goal: to improve it beyond its current limits and eliminate all or most of its current problems.
Japan Display: lithographic improvement to increase brightness and consumption
Japanese Displaythat consortium of Japanese manufacturers such as Toshiba, Sony or Panasonic, among others, is improving manufacturing processes based on evaporation and different layers (FMM) to switch to a new system invented by themselves, known or as eLEAP (andpositive environment Lithography with maskless ANDxtreme long life low power and high luminance and Any shape Patterningdeposition) -yes, we don’t know what kind of twisted mind has thought it a good idea to make an acronym with that-.
The basic idea is that the current subpixels are larger and therefore take up more surface area on the screen. Being larger and occupying more space, their opening ratio increases by more than 30%, thus achieving a significant improvement in brightness or greater energy efficiency, matching the current brightness.
Example of increasing the size of sub-pixels in an eLEAP OLED
According to Japanese Display, eLEAP technology not only manages to increase the brightness of the sub-pixels -now larger- in a percentage equal to that which has grown (30%), but also, since each panel is made up of 8 million 300 thousand pixels… they promise that the brightness can be more than double that of current OLEDs. And being larger, they also have a longer shelf life.
And not only that, but the current 8th generation plants could be adapted with this technology to manufacture panels larger than 100 inches (by using larger sub-pixels, it is easier) and also reducing the manufacturing cost. They seem all advantages. according to own Japanese Displaythis technology should be ready for mass use by the end of 2022.
Improvement in the phosphorescent blue emitter of PHOLED
As reported by the Korean newspaper The Elec last month UniversalDisplay unveiled this promising technology, which, like that of Japan Display, points to its availability at the end of 2022, although yes, with the aim of having the first phosphorescent blue PHOLEDs ready on the market in 2024. UniversalDisplay already partnered in 2018 with Sharp to supply its PHOLED phosphorescent OLED materials (pHosphor EITHERorganic Lok ANDmission Diplay).
But the thing does not end here, since the Korean manufacturer LORDIN is also developing fluorescent blue OLED emitters with an Internal Quantum Efficiency (IQE) of 90%, compared to 25% of current OLED panels for televisions and smartphones. Development that seems to be in the final stages, among other things, because there is talk of an arrival on the market at the end of the year. This massive increase in efficiency was made possible by being able to control the rate of energy transfer between molecules within the material.
LORDIN is also expected to introduce blue PHOLED panels in 2024 and this component, in addition to extending the longevity of OLEDs, can be used to produce brighter WOLED and QD-OLED panels. In other words, in a couple of years we will be able to see the first new generation OLED televisions. with a longer life expectancy and with a higher brightness thanks to the phosphorescent blue emitters, showing that OLEDs have not yet reached the ceiling.
Can you imagine mixing it with the QD-OLED Quantum Dots and with the increase in the size of the sub-pixel technology promised by Japan Display? but wait, there is more.
Idemistu Kosan Blue Emitter Upgrade
Idemitsu Kosana Japanese company focused on the research of different types of electronic materials, display devices, etc., ensures that it has developed the most efficient fluorescent blue OLED emitter in the world, surpassing the PHOLED of LORDIN and Universal Display that we saw above.
Idemitsu’s new system achieves a EQE of 14% (at a current density of 10 mA/cm2), a lifespan of more than 400 hours (LT95 at 50 mA/cm2), and a color point of 0.14,0.08. The new material system uses a two-layer tandem structure of blue OLED emitters. Idemitsu says that by separating the part that causes charge recombination and using technology TTF (Triplet-Triplet Fusion) achieved a much higher brightness emission than expected.
It seems that Idemitsu Kosan is expanding its OLED panel production capacity. In December 2020, the company began production of OLED materials at its new factory in Chengdu, China.
In 2018, Idemitsu signed an agreement with Toray to jointly develop OLED materials and an agreement with LG Chem to share its OLED material patents. In 2019, Toray and Idemitsu announced that the companies jointly developed a device Red TADF OLED which is the most efficient emitter in the world with 46 cd/A.
TADF: the eternal promise that never comes
TADF stands for Thermally Activated Delayed Fluorescencea kind of high-efficiency blue emitter that is thermally activated.
In this technology, the fluorescent filter used in OLED televisions (which generates RGB colors) would be replaced by a thermally activated delayed fluorescence transmitter (TADF) manufactured by the Cynora company. This technology converts the source that was used until now to generate light by the new fluorescence transmitter and also allows to reduce the electrical stress in organic materials.
TADF combines two advantages: the useful life of fluorescence and efficiency of phosphorescence. In addition, this technology is compatible with the manufacture of panels using 3D printers.
Using this new process would allow WRGB OLED TVs to increase peak nits, but especially overall scene brightness (APL). That is, the maximum peak could go to about 1300-1400 nits, but the general scene would no longer be limited to about 150 nits when the screen is 100% white, but about double (300 nits). The problem is that it has been present since 2018 and for one reason or another, it never applies to OLED televisions.
TCL inkjet printing system
It’s not all about improving image quality or brightness. You also have to look at the cost of production and this technique, which we explain in greater depth in this articleBet on it.
What this inkjet printing system does is deposit the substrates accurately and without the need to use a mask, reducing the number of lost particles to increase performance. These significant advantages make this technology interesting for many companies and virtually all OLED manufacturers have active inkjet printing development projects, although it seems that TCL will be the first to launch TVs with this manufacturing process.
As we have indicated beforeOLED panels made using this process are much cheaper since much less material is lost, without losing the qualities offered by organic light-emitting diode technology.
LG Display Micro Convex Lens System
We also saw this news the other day. Basically and in short, LG has applied a layer of microlenses to the organic light-emitting diodes to take care of adjusting the light path. With this, it is reflected inside the panel causing it to be projected towards the user, significantly improving the efficiency of light extraction, thus increasing brightness levels.
The manufacturer has called this new technology MLAeither metal illuminated lens array. Y the first model to release it is a 77-inch 8K OLED TV that has this new panel that manages to double the values of current technologies to reach 2000 nits of brightness.
To achieve this, OLED panels are deposited through a deposition process and shaped to take the shape of a convex lens. Now, all you have to do is adjust the angle of the light that is lost inside the OLED panel and amplify it to increase the efficiency of the light.
