848 ppi high-brightness active-matrix micro-LED micro-display using GaN-on-Si epi-wafers towards mass production

Qi, Limei; Zhang, Xu; Chong, Wing Cheung; Li, Peian; Lau, Kei May

doi:10.1364/oe.419877

Cited by 55 publications

(26 citation statements)

References 34 publications

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“…For micro-LEDs, the situation is more complicated because the EQE depends on the chip size. Based on previous studies [130][131][132][133] , we separately calculate the luminous efficacy for RGB micro-LEDs with chip size ≈ 20 µm. For the scheme of direct combination of RGB micro-LEDs, the luminous efficacy is around 5 lm/ W. For QD-conversion with blue micro-LEDs, the luminous efficacy is around 10 lm/W with the assumption of 100% color conversion efficiency, which has been demonstrated using structure engineering 114 .…”

Section: Comparison Of Light Engine Performancementioning

confidence: 99%

Augmented reality and virtual reality displays: emerging technologies and future perspectives

et al. 2021

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With rapid advances in high-speed communication and computation, augmented reality (AR) and virtual reality (VR) are emerging as next-generation display platforms for deeper human-digital interactions. Nonetheless, to simultaneously match the exceptional performance of human vision and keep the near-eye display module compact and lightweight imposes unprecedented challenges on optical engineering. Fortunately, recent progress in holographic optical elements (HOEs) and lithography-enabled devices provide innovative ways to tackle these obstacles in AR and VR that are otherwise difficult with traditional optics. In this review, we begin with introducing the basic structures of AR and VR headsets, and then describing the operation principles of various HOEs and lithography-enabled devices. Their properties are analyzed in detail, including strong selectivity on wavelength and incident angle, and multiplexing ability of volume HOEs, polarization dependency and active switching of liquid crystal HOEs, device fabrication, and properties of micro-LEDs (light-emitting diodes), and large design freedoms of metasurfaces. Afterwards, we discuss how these devices help enhance the AR and VR performance, with detailed description and analysis of some state-of-the-art architectures. Finally, we cast a perspective on potential developments and research directions of these photonic devices for future AR and VR displays.

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Section: Comparison Of Light Engine Performancementioning

confidence: 99%

Augmented reality and virtual reality displays: emerging technologies and future perspectives

et al. 2021

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“…2020) [ 33 ]. Qi et al built a micro-LEDs array on a 0.55-in (400 × 240) gallium nitride substrate with a pixel density of 848 PPI and full width at half maximum (FWHM) of 18.2 nm to produce a high-brightness, high-resolution micro-LEDs display [ 34 ]. The aforementioned findings indicate that combining blue micro-LEDs with QDs is currently the best solution for achieving full color.…”

Section: Introductionmentioning

confidence: 99%

Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

2022

Nanoscale Res Lett

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A common full-color method involves combining micro-light-emitting diodes (LEDs) chips with color conversion materials such as quantum dots (QDs) to achieve full color. However, during color conversion between micro-LEDs and QDs, QDs cannot completely absorb incident wavelengths cause the emission wavelengths that including incident wavelengths and converted wavelength through QDs, which compromises color purity. The present paper proposes the use of a recycling-reflection color-purity-enhancement film (RCPEF) to reflect the incident wavelength multiple times and, consequently, prevent wavelength mixing after QDs conversion. This RCPEF only allows the light of a specific wavelength to pass through it, exciting blue light is reflected back to the red and green QDs layer. The prototype experiment indicated that with an excitation light source wavelength of 445.5 nm, the use of green QDs and RCPEFs increased color purity from 77.2% to 97.49% and light conversion efficiency by 1.97 times and the use of red QDs and RCPEFs increased color purity to 94.68% and light conversion efficiency by 1.46 times. Thus, high efficiency and color purity were achieved for micro-LEDs displays. Graphical Abstract

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“…Compared with self-power-consuming OLED technology, the LCD technology is superior in terms of lifetime, cost, resolution and peak brightness 6 . Many technology giants are employing cost-effective LCDs for AR dis-plays.…”

Section: Introductionmentioning

confidence: 99%

“…At 2017 SID display Week, Samsung launched a 1.96-inch ultra-high definition (UHD) display for HM-Ds, with an amazing pixel density of 2250 PPI, and BOE exhibited a retina VR display (2300 PPI) with a size of 5.3 cm. Although the LCD technology has the advantages as mentioned above, its response time is about 100 times larger than that of the OLED technology 6 , as listed in Table 1. To solve the problem of long response time in traditional LCD, Gou et al reported a fire-new mode, including a hole-type vertical alignment-fringe field switching (VA-FFS) technique, which optimized liquid crystal materials by electrodynamic optimization 4 .…”

Section: Introductionmentioning

confidence: 99%

An overview on the principle of inkjet printing technique and its application in micro-display for augmented/virtual realities

Yang¹,

Lin²,

Wu³

et al. 2022

OEA

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Augmented reality (AR) and virtual reality (VR) are two novel display technologies that are under updates. The essential feature of AR/VR is the full-color display that requires high pixel densities. To generate three-color pixels, the fluorescent color conversion layer inevitably includes green and red pixels. To fabricate such sort of display kits, inkjet printing is a promising way to position the color conversion layers. In this review article, the progress of AR/VR technologies is first reviewed, and in succession, the state of the art of inkjet printing, as well as two key issues -the optimization of ink and the reduction of coffee-ring effects, are introduced. Finally, some potential problems associated with the color converting layer are highlighted.

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848 ppi high-brightness active-matrix micro-LED micro-display using GaN-on-Si epi-wafers towards mass production

Cited by 55 publications

References 34 publications

Augmented reality and virtual reality displays: emerging technologies and future perspectives

Augmented reality and virtual reality displays: emerging technologies and future perspectives

Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

An overview on the principle of inkjet printing technique and its application in micro-display for augmented/virtual realities

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