Other display makers are likely working to accomplish the same thing. According to Samsung this is a problem that is solved on the R&D scale but still needs to be scaled to manufacturing. Polarizer redesign - Due to the fact that QDs depolarize light, the 2nd polarizer must move before QDs in the optical path (in cell).Scientists have been working on overcoming these hurdles, many of which have seen significant progress recently. The technical challenges associated with this technology are very different than the challenges required to implement QD films. No new technology comes easy, and QD color filters are no exception. I know what you are thinking, if there are all these advantages, why haven't people already done this? Technical hurdles These are just a few of the advantages of QD color filters over QD films. Thinner panel - Reduced components and in-cell polarizer means an overall thinner display.Lower light flux and temperature - Further from LED source and after the liquid crystal and polarizers means it's a less harsh environment for the QDs to withstand.As viewers we should see a dramatic difference in wide angle viewing. Wider viewing angle - QDs emit in all directions and are closer to the front of the screen.This can bring huge improvements in efficiency and brightness (see table to the right from Nanosys) Brighter/more efficient - Light conversion (blue to red/green) happens after the liquid crystal layer and other optical films.Now, instead of blocking light the color filter is converting light! The two diagrams below summarize the differences in a QD film display, and a QD color filter display (images courtesy of Samsung Display). In a QD color filter, there would be only red and green QD layers, and the blue sub-pixel would be empty which would allow for transmission of the blue LED backlight (remember, displays using QDs have blue LEDs, not white ones). QDs can also be dispersed in polymers and cured (QLED TVs all have films of QDs in a photopolymer after all), so it makes perfect sense to consider replacing the current colored dyes with quantum dots to make an active component instead of a passive one. Each color must be deposited and patterned over a large area independently using a combination of UV-curing, etching, and thermal processing (hard bake) to pattern and harden the photopolymer. Current color filters are made by patterning photoresists (the same technology used to make computer chips). QD color filters coupled with a blue LED could give far better color than current white LED + color filter (potentially even better than QD films, see table below). QDs could act as a direct replacement of current color filter technology, using red and green QDs to replace current colored materials (with the blue sub-pixel being non-colored). If you look very closely at your TV, you might be able to make out individual pixels and sub-pixels (red, green, and blue). It could be useful to refer back to this image throughout this post. The structure below also outlines the various components in a modern display so you can see where all the components are in relation to one another. If you are not familiar, I recommend reviewing this technology in the following video (there are many others out there, this is just one example with good animation, if you want a more in-depth review, look here). This blog post will require an understanding of how an LED/LCD display (like your tablet, computer monitor, or TV) functions. I wrote in the past about quantum dots on chip as a game-changing technology for displays and lighting (which is true) but many people believe that QDs may find their way into color filters before they make it on chip.Ī quick thank you up front to folks at Samsung, Nanosys, and Nanoco who were willing to talk with me about their work on QD color filters in preparation for this blog post. Quantum dot (QD) color filters are becoming a hot topic in the display world lately, so I thought it would make sense to educate people on this technology and how it may change the quantum dot display (QLED) landscape. No, I have not seen one for myself, but you and I may soon have that opportunity. That's what people are saying after seeing TVs that contain QD color filters.
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