The Progress of QD Color Filters
Despite being available on the commercial market for a few years, quantum dot (QD) displays are still broadly considered a technology of the future, having revolutionized the traditional liquid crystal display (LCD) matrix by enabling true color saturation a wider color gamut than any other competing technology.
QD TVs are currently considered the optimal way to achieve BT2020 standards of ultra-high definition, while organic light-emitting diode (OLED) TVs retain the edge in terms of true black representation on-screen. These competing parameters reflect the current landscape of the display market, with industry experts divided in their preferences for either QDLED and OLED displays. However, there is a unifying consensus that the onset of QD color filters could completely change the balance of the industry.
What are QD Color Filters?
QD color filters are conceptual components designed to replace traditional RGB converters in LCD and QDLED matrices. Current iterations of QD-enhanced displays utilize a backlight of LEDs as the excitation source, which shines monochromatic blue light through a series of polarizers, liquid crystal layers, red and green QD layers, and a color filter to create highly-saturated images onscreen.
Manufacturers have been working on numerous designs for direct-view QD color filters, which would reduce the layered composition of displays to enhance pixel-to-pixel control and enable manufacturing of thinner displays.
How Would QD Color Filters Work?
QD color filters are formed of unique nanoparticle dispersions comprising QDs of multiple emission wavelengths. Nanoparticle solutions are dispersed on a substrate panel and integrated onto a thin matrix comprising a bank of red and green QDs, and an in-cell polarizer. Each individual pixel in a direct-view QD color filter would house red and green QDs. The red and green crystals absorb blue light and transmit light of their respective wavelengths, while one subpixel would transmit blue light directly from the back of the array.
This prototypical matrix would deliver the best possible viewing angles and cover 100% of the DCI/P3 protocol and potentially the BT2020 standard.
How Close are QD Color Filters?
The progress of QD color filter technology has been hindered by some technical challenges, as the panel production needs to be adapted. For example, an in-cell polarizer needs to be developed. Furthermore, the application of the red and green quantum dots is still an open question. The race between the photolithographic and the ink jet approach is still open. On the quantum dot size, the light absorbance potential of the quantum dots has been a weakness.
Fortunately, the emergence of cadmium-free Perovskite QDs with x-fold absorbance properties if compared to traditional Cadmium and Indium-based QDs has re-accelerated the innovative drive to bring QD color filters to the mainstream commercial market. These materials have been effectively ink-jet and photo-lithographically printed to produce outstanding optical panels for direct-view QD color filter displays.
Leading display providers are still prototyping QD color filter TVs with outstanding high dynamic ranges, unparalleled viewing angles, and thinner displays than ever.
QDs from Avantama
Avantama are leading suppliers of Perovskite QDs for color displays and organic photovoltaic cells. Our QD dispersions have demonstrably improved optical properties over OLED displays, with reduced manufacturing costs compared to QDs formulated from other techniques.