Display Resolution Increases by 3D-Printing Quantum Dot Nanopixels

A display technology developed at the Korea Electrotechnology Research Institute (KERI) produces 3D pixels with nanoscale dimensions by 3D-printing quantum dots (QDs) embedded in polymer nanowires. The technology — called “nanophotonic 3D printing” by the research team — could be used to achieve superhigh-resolution displays in TVs, smartphones, virtual reality headsets, and other devices.

The more pixels on a display screen and the more densely the pixels are integrated, the higher the resolution. To increase the number of pixels that can appear on a screen, the traditional approach has been to reduce the pixel size. Achieving a higher definition through a smaller pixel size has become a key to leading in this competitive market, but reducing pixel size can also limit light intensity.

A Korean research team developed a technology to produce a nano display with a super-high-resolution based on a 3D printing technique. Courtesy of Korea Electrotechnology Research Institute (KERI).

A Korean research team developed a technology to produce a nano display with a super-high-resolution based on a 3D printing technique. Courtesy of Korea Electrotechnology Research Institute (KERI).

A South Korean research team developed a technology to produce a nanodisplay with a superhigh resolution based on a 3D-printing technique. Courtesy of Korea Electrotechnology Research Institute (KERI).

The KERI team believed that the light intensity required for a superhigh resolution could be achieved by producing pixels with a 3D structure. Instead of using a 2D patterning approach, the team applied a 3D structure to its pixels to overcome light intensity issues. The 3D layout enabled a twofold increase in brightness with full colors (red, green, blue), compared to conventional thin-film-based structures, and had no significant effects on the spatial resolution.

Using its nanophotonic 3D-printing technology, the team demonstrated the production of pixels with a lateral dimension of 620 nm and a pitch of 3 μm for each of the red, green, and blue colors. The researchers demonstrated the three primary colors in 5600 pixels per inch (PPI), exceeding that of 8K QLED TV (100 PPI), laptop (200 PPI), and smartphone (800 PPI) devices, while surpassing the limit of commercial technology (1000 PPI) by five times or more. The team also demonstrated individual control of the brightness based on a simple adjustment of the height of the 3D pixels.

The pixel density provided by the KERI team’s approach could be applied to future displays for VR and AR, beam projectors, and other applications requiring superhigh resolution. One of the biggest benefits of the nanophotonic 3D-printing technology, the researchers believe, is that the QDs can be 3D-printed onto polyimide or polyethylene terephthalate materials, which are used to produce flexible substrates. This could allow the technology to be used for wearable or rollable devices.

The research was published in ACS Nano (www.doi.org/10.1021/acsnano.0c04075).

Published: August 2020

Glossary

optoelectronics: Optoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light and its interactions with different materials. The term "optoelectronics" is a combination of "optics" and "electronics," reflecting the interdisciplinary nature of this field. Optoelectronic devices convert electrical signals into optical signals or vice versa, making them crucial in various technologies. Some key components and applications of optoelectronics include: ...
nano: An SI prefix meaning one billionth (10-9). Nano can also be used to indicate the study of atoms, molecules and other structures and particles on the nanometer scale. Nano-optics (also referred to as nanophotonics), for example, is the study of how light and light-matter interactions behave on the nanometer scale. See nanophotonics.
nanophotonics: Nanophotonics is a branch of science and technology that explores the behavior of light on the nanometer scale, typically at dimensions smaller than the wavelength of light. It involves the study and manipulation of light using nanoscale structures and materials, often at dimensions comparable to or smaller than the wavelength of the light being manipulated. Aspects and applications of nanophotonics include: Nanoscale optical components: Nanophotonics involves the design and fabrication of...
quantum dots: A quantum dot is a nanoscale semiconductor structure, typically composed of materials like cadmium selenide or indium arsenide, that exhibits unique quantum mechanical properties. These properties arise from the confinement of electrons within the dot, leading to discrete energy levels, or "quantization" of energy, similar to the behavior of individual atoms or molecules. Quantum dots have a size on the order of a few nanometers and can emit or absorb photons (light) with precise wavelengths,...
3d printing: 3D printing, also known as additive manufacturing (AM), is a manufacturing process that builds three-dimensional objects layer by layer from a digital model. This technology allows the creation of complex and customized structures that would be challenging or impossible with traditional manufacturing methods. The process typically involves the following key steps: Digital design: A three-dimensional digital model of the object is created using computer-aided design (CAD) software. This...
superresolution: Superresolution refers to the enhancement or improvement of the spatial resolution beyond the conventional limits imposed by the diffraction of light. In the context of imaging, it is a set of techniques and algorithms that aim to achieve higher resolution images than what is traditionally possible using standard imaging systems. In conventional optical microscopy, the resolution is limited by the diffraction of light, a phenomenon described by Ernst Abbe's diffraction limit. This limit sets a...

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