Quantum dot specialist QD Vision and Chinese TV maker Konka have unveiled a pair of new UHD TVs, which use QD Vision’s Color IQ quantum dot optics. QD Vision says its technology is already shipping in millions of TVs, and the deal with Konka will certainly help it retain its position as a leading quantum dot vendor.
Quantum dot films and filtering will be very important for LCD panels in the near future. The dots themselves are nanocrystal particles made using semiconductor materials that are so small they exhibit quantum mechanical properties – specifically, quantum entanglement due to the dot’s radii being smaller than the Bohr radius.
They can be used to filter the back or edge lighting that illuminates the screen, allowing engineers to better calibrate the backlight’s color frequency output to create a picture with much improved color by eliminating the cross talk between the color channels – or used to create an LED itself, although this approach is still uneconomic and far less common than the color-tuning film.
Using this filtering process, targeting blue tones, but also yellows too, the color reproduction of the output can be significantly improved – enough to rival the color accuracy found in the UHD standard. The dots emit different colors of light when they are stimulated by electrons or photons (an electrical charge or light respectively), and can therefore be arranged to produce the desired hue, and manufactured into a film that sits between the backlighting and the pixels.
The major benefit derived from this process is that you don’t need to alter the source signal or input to achieve better color reproduction – meaning that the customers and operators don’t have to alter any of the equipment in their homes or infrastructure deployments. Unlike High Dynamic Range (HDR), which requires additional data to be injected into the pipe leading to the viewer, quantum dots enable picture quality improvements using the same source material.
Quantum dots have been positioned as a threat to 4K TVs, as strict 4K only improves on the resolution of a 1080p signal, and not the color gamut, framerate, or HDR. UHD uses the 3840x2160p resolution that is shared by 4K, but also increases those facets – jumping from the Rec. 709 definition to Rec. 2020, mandating HDR, and improving the framerate from a max of 60fps up to 120fps.
Of course, all those improvements require more bandwidth, which is a scarce resource in OTT delivery systems, although perhaps more manageable in satellite and cable. Either way, Netflix’s current requirements for a HEVC stream in 4K (not UHD with the extra data) sits at around 15Mbps. A UHD signal is going to be in the twenties at least, and the issue of content and source signal is still 4K/UHD’s biggest stumbling block.
However, with the improvements in color afforded by quantum dot technologies, as well as the increase in contrast and black reproduction that full-array LED backlighting can create (a technology that is cropping up in more and more TVs), the Full HD TV itself can rival a 4K screen in the showroom – until the size of gets so big that you begin to detect visible pixilation, at sizes north of 70-inches.
But adding HDR to the signal (as Amazon is planning; see separate article) would also improve the image quality without dramatically increasing the required bandwidth. This would add up to a picture quality that can outmatch 4K and rival UHD at smaller screen sizes – although the lower refresh rate means it will lose out in tests using fast-moving images.
As UHD prices have come down in recent months, the improvements that quantum dot and HDR can afford to regular Full HD panels are perhaps not as advantageous. The UHD TV will have all the benefits of the improved color, contrast and framerate if it conforms to the UHD spec, but the falling UHD prices and the improving quality of LCD screens threatens one technology in particular – OLED.
Once hailed as the future of panel technology, despite having mountains of R&D cash thrown at it, OLED still hasn’t established itself as a medium to rival LED LCD shipments. While its color reproduction and contrast win out in many tests, it is nowhere near as affordable as the LCD panels.
To this end, Samsung has virtually abandoned its OLED ambitions in favor of quantum dots, and while LG still asserts its OLED dominance, it’s also quietly moved into the quantum dot market with its webOS powered QD sets.
Figures from DisplaySearch count China as holding two-thirds of the global demand for UHD and 4K TVs, and new researcher Touch Display Research is currently forecasting that 60% of TVs will have quantum dots in them by 2025. Basically, in the short and medium term, if you want to find a UHD QDTV, your best bet is China.
“QD Vision’s Color IQ technology helps make these new televisions among the best on the market,” said Zhimao Zhuo, Konka’s Senior Product Manager. “They deliver a unique combination of sleek design and a stunning viewing experience, all for a very compelling price.”