Blue
In our note yesterday, we mentioned Samsung Display’s (pvt) potential expansion of its QD/OLED display capacity, both through improvements in process tact time and the eventual conversion of shuttered LCD fab to additional QD/OLED lines. Some of what we noted was derived from a recent speech made by the CEO of Samsung Display where he made a number of specific references to SDC’s plans for QD/OLED, a technology that SDC is promoting as an alternative to LG Display’s (LPL) WOLED. The two large panel display technologies are the same in that they are both based on OLED emitters as light sources, but differ in the way that they quantify that light into Red, green, and blue sub-pixels that are necessary for full color displays.
WOLED technology uses a yellow/green (We note that yellow is a combination of green and red in light) phosphorescent OLED emitter combined with a blue fluorescent emitter as its light source. With all three primary colors represented, the mix produces white light. The white light is then passed through a color filter, essentially a sheet of red, green, and blue dots of phosphor materials. The red phosphor dots allow the red component of the white light to pass through, while the green and blue dots do the same, creating an RGB pixel, one of ~8.3m on a 4K display. While this is a cost effective way of producing an OLED TV display, as each sub-pixel blocks what is theoretically 2/3 of the light, much of the light intensity of the OLED materials is lost at the color filter.
Samsung Display uses a different technology for their QD/OLED displays. The light source is a blue fluorescent emitter, similar to the type used in the WOLED process, but the color filter phosphors are replaced with red and green quantum dots. Quantum dots differ from phosphors in that they do not block light, but convert it from one frequency to another, which corresponds to changing the color, so in the SDC system, in theory, the blue light is converted to red and green sub-pixels while the blue light passes through unchanged without filtering out other color components, producing a brighter display.
Both systems has a drawback, and that is they rely on blue phosphorescent emitters, which differ from phosphorescent OLED emitters in that fluorescent emitter are only able to emit 25le to generate 25% of the light that phosphorescent emitter materials can. The physics behind this issue is complex, but if OLED panel producers had the ability to use a blue phosphorescent emitter they would, other than the fact that they are not commercially available, hence the reliance on the lower output fluorescent blue. Again, the physics behind why a blue phosphorescent emitter is not available is complex, but leave us to say that the higher energy levels of blue phosphorescent emitters causes them to break down more quickly than red or green, and deep blue phosphorescent emitters do not yet have the lifetime needed for commercial use.
There is an alternative, which is a derivative of fluorescent blue called TADF (Thermally activated delayed fluorescence) which improves the characteristics of generic blue fluorescent emitter materials, but they are still on the cusp of having the characteristics needed for commercial display, which leaves both Samsung Display and LG Display to use fluorescent blue emitters and look for ways to improve output until a blue TADF or phosphorescent OLED emitter can be commercialized. Universal Display (OLED) and a number of other display material suppliers have been working toward the commercialization of such a material, with UDC expecting product by 2024, along with SDC itself, who has license agreements with UDC. Samsung recently cited its own developments in the development of a blue platinum-based phosphorescent emitter material but gave no timeline as to its potential commercialization or internal use.
Back to the speech given by Samsung Display’s CEO this week…what caught our attention was the reference he made to changing the blue fluorescent emitter material currently used in the QD/OLED process to a blue phosphorescent ar blue TADF material to increase the light emitting efficiency. This seems to imply that SDC is considering changing the QD/OLED stack with what would have to be a commercial blue emitter that has been developed by a partner or affiliate, which would be a major step forward in the development of OLED materials. We expect the production of such a material would be done in outside of Samsung itself, which opens the question up as to whether this material will be exclusive to Samsung or whether it will be made available to other OLED producers. While the advantage to Samsung would be obvious if the IP is limited, the licensing of said IP would allow the OLED industry to progress further, particularly large panel; OLED devices, and would improve the characteristics of both WOLED and QD/OLED, as well as improving small panel OLED displays by increasing their efficiency and reducing power requirements. While this was a mention in a longer speech, we see it as carrying significant weight toward the commercialization of a blue phosphorescent material. Only 494 days to wait to see if the prediction rings true…
WOLED technology uses a yellow/green (We note that yellow is a combination of green and red in light) phosphorescent OLED emitter combined with a blue fluorescent emitter as its light source. With all three primary colors represented, the mix produces white light. The white light is then passed through a color filter, essentially a sheet of red, green, and blue dots of phosphor materials. The red phosphor dots allow the red component of the white light to pass through, while the green and blue dots do the same, creating an RGB pixel, one of ~8.3m on a 4K display. While this is a cost effective way of producing an OLED TV display, as each sub-pixel blocks what is theoretically 2/3 of the light, much of the light intensity of the OLED materials is lost at the color filter.
Samsung Display uses a different technology for their QD/OLED displays. The light source is a blue fluorescent emitter, similar to the type used in the WOLED process, but the color filter phosphors are replaced with red and green quantum dots. Quantum dots differ from phosphors in that they do not block light, but convert it from one frequency to another, which corresponds to changing the color, so in the SDC system, in theory, the blue light is converted to red and green sub-pixels while the blue light passes through unchanged without filtering out other color components, producing a brighter display.
Both systems has a drawback, and that is they rely on blue phosphorescent emitters, which differ from phosphorescent OLED emitters in that fluorescent emitter are only able to emit 25le to generate 25% of the light that phosphorescent emitter materials can. The physics behind this issue is complex, but if OLED panel producers had the ability to use a blue phosphorescent emitter they would, other than the fact that they are not commercially available, hence the reliance on the lower output fluorescent blue. Again, the physics behind why a blue phosphorescent emitter is not available is complex, but leave us to say that the higher energy levels of blue phosphorescent emitters causes them to break down more quickly than red or green, and deep blue phosphorescent emitters do not yet have the lifetime needed for commercial use.
There is an alternative, which is a derivative of fluorescent blue called TADF (Thermally activated delayed fluorescence) which improves the characteristics of generic blue fluorescent emitter materials, but they are still on the cusp of having the characteristics needed for commercial display, which leaves both Samsung Display and LG Display to use fluorescent blue emitters and look for ways to improve output until a blue TADF or phosphorescent OLED emitter can be commercialized. Universal Display (OLED) and a number of other display material suppliers have been working toward the commercialization of such a material, with UDC expecting product by 2024, along with SDC itself, who has license agreements with UDC. Samsung recently cited its own developments in the development of a blue platinum-based phosphorescent emitter material but gave no timeline as to its potential commercialization or internal use.
Back to the speech given by Samsung Display’s CEO this week…what caught our attention was the reference he made to changing the blue fluorescent emitter material currently used in the QD/OLED process to a blue phosphorescent ar blue TADF material to increase the light emitting efficiency. This seems to imply that SDC is considering changing the QD/OLED stack with what would have to be a commercial blue emitter that has been developed by a partner or affiliate, which would be a major step forward in the development of OLED materials. We expect the production of such a material would be done in outside of Samsung itself, which opens the question up as to whether this material will be exclusive to Samsung or whether it will be made available to other OLED producers. While the advantage to Samsung would be obvious if the IP is limited, the licensing of said IP would allow the OLED industry to progress further, particularly large panel; OLED devices, and would improve the characteristics of both WOLED and QD/OLED, as well as improving small panel OLED displays by increasing their efficiency and reducing power requirements. While this was a mention in a longer speech, we see it as carrying significant weight toward the commercialization of a blue phosphorescent material. Only 494 days to wait to see if the prediction rings true…
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