Vizio Lands Patent for Methods of Fashioning High-Precision Quantum-Dot TVs
A method for fashioning quantum-dot LCD displays for wider-color-gamut TVs but without the imprecision of using color filter films for the quantum-dot components is described in a U.S. patent that Vizio landed Tuesday at the Patent and Trademark Office. The patent (9,356,204) is based on a December 2013 application and lists Vizio Chief Technology Officer Matthew McRae as the lone inventor.
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Technology to improve the color gamut in LCD display panels is “an ongoing effort,” the patent says. “The color gamut of backlighting technology is a tradeoff between acceptable colors displayed to the viewer and manufacturing process and cost,” it says. Quantum-dot technology is showing particular promise because it’s similar to that used in OLED displays, it said. One of quantum dots’ advantages “is that they emit very pure light,” it says. But peak development of next-generation display technology using quantum dots “is still several years off,” it says.
Some companies have introduced technology that uses color filter films with red and green quantum dots embedded into them, the patent says. The use of color filter film on the back surface of LCD display panels is “well known in the art,” it says. “These films have colored dots of red, blue and green printed or deposited on the film. The dots are arranged on the film such that when the film is applied to the back of a LCD display panel they're aligned so each dot is directly over the area where a matching pixel gate is positioned within the LCD panel itself.
The use of color filter films is advantageous because it “allows a single white light source to be used for providing light to the LCD panel,” the patent says. “A problem however with this scheme is that alignment of the color dots on the film is extremely critical and aligning and adhering the film to the back surface of the LCD panel has to be very precise so that the color dots are each covering a matching pixel.”
As an alternative, the patent describes “a preferred embodiment” in which red and green quantum dots are mixed into the material that forms the “lens cap” that sits on top of an LED in a backlight. “The resulting matrix operates when stimulated at the back surface with blue light, to emit a mixture of red and green light with blue light which will appear as white light,” it says. The lens then focuses and steers the resultant white light to the back of the LCD panel or to the color filter film, it says. In another embodiment, “the quantum dot matrix may also include glass or other crystalline crystals to enhance the scattering of blue light through the lens matrix,” it says. Vizio representatives didn’t comment on possible commercialization plans of the technology described in the patent. Vizio currently markets quantum-dot technology in its 65-inch Reference Series LCD TVs.
Representatives of Nanosys, which bills itself as the world’s leading supplier of quantum dots, didn’t comment Tuesday on the Vizio patent. Nanosys spent much of last week’s Display Week conference extolling the supremacy of quantum dots’ color performance over that of OLED displays (see 1605240002). Though OLED technology already is shipping on tens of millions of smartphones, Nanosys representatives cited IHS forecasts that quantum dots “will outpace the entire OLED industry this year” in terms of the number of square meters of panels shipped “on the strength of large-area TV shipments.”