Design of a large field-of-view two-dimensional geometrical waveguide

Zhou, Yao; Zhang, Jufan

doi:10.1016/j.rio.2021.100147

Cited by 6 publications

(4 citation statements)

References 6 publications

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“…But the major problem of the geometric waveguide combiner is the stray light and ghost images caused by the undesired reflections on the couplers, which can severely degrade the image quality, especially when FoV increases in the direction of pupil expansion. Based on previous research [37,39,40], stray light is primarily generated in three ways, as illustrated in Fig. 2a-c.…”

Section: Issues Induced By Geometric Couplersmentioning

confidence: 99%

Waveguide-based augmented reality displays: perspectives and challenges

Ding,

Yang,

et al. 2023

eLight

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Augmented reality (AR) displays, as the next generation platform for spatial computing and digital twins, enable users to view digital images superimposed on real-world environment, fostering a deeper level of human-digital interactions. However, as a critical element in an AR system, optical combiners face unprecedented challenges to match the exceptional performance requirements of human vision system while keeping the headset ultracompact and lightweight. After decades of extensive device and material research efforts, and heavy investment in manufacturing technologies, several promising waveguide combiners have been developed. In this review paper, we focus on the perspectives and challenges of optical waveguide combiners for AR displays. We will begin by introducing the basic device structures and operation principles of different AR architectures, and then delve into different waveguide combiners, including geometric and diffractive waveguide combiners. Some commonly used in-couplers and out-couplers, such as prisms, mirrors, surface relief gratings, volume holographic gratings, polarization volume gratings, and metasurface-based couplers, will be discussed, and their properties analyzed in detail. Additionally, we will explore recent advances in waveguide combiner design and modeling, such as exit pupil expansion, wide field of view, geometric architectures of waveguide couplers, full-color propagation, and brightness and color uniformity optimization. Finally, we will discuss the bottlenecks and future development trends in waveguide combiner technologies. The objective of this review is to provide a comprehensive overview of the current state of waveguide combiner technologies, analyze their pros and cons, and then present the future challenges of AR displays.

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Section: Issues Induced By Geometric Couplersmentioning

confidence: 99%

Waveguide-based augmented reality displays: perspectives and challenges

Ding,

Yang,

et al. 2023

eLight

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“…A typical transmittance to the reflectance ratio is often considered to be 1:1, but this can be varied based on the specific requirements and applications by adjusting the coating thickness and materials. Partial mirrors are commonly used in couplers of waveguides or lightguides to extend the effective EB of a NED or HUD through the application of EPE. − The authors of Figure a implemented an AR HUD system using a waveguide combiner composed of mirror and BS having gradually increasing reflectivity . In this system, the intensity of light emerging from the waveguide gradually diminishes due to the multiple reflections between mirror and BS.…”

Section: Combined Usage Of Optical Elementsmentioning

confidence: 99%

Recent Applications of Optical Elements in Augmented and Virtual Reality Displays: A Review

Choi,

Han,

Min

et al. 2024

ACS Appl. Opt. Mater.

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Augmented reality (AR) and virtual reality (VR) are emerging as a next-generation display platform, surpassing conventional flat panel displays. The AR/VR technologies are garnering considerable attention from both industry and academia as they provide immersive user experiences and smooth interaction between the real and digital worlds. The current AR/VR displays, however, still face several challenges including limited field of view, small eye-box, conflict between the vergence and accommodation, bulky form factor, and heavy weight. This paper aims to provide a comprehensive view of optical elements of AR/VR displays, emphasizing how they enhance the performance and user experience of the AR/VR displays. Various techniques are explained in the following two principal aspects: AR/VR displays based on (1) holographic optical elements and metasurfaces, and (2) combined usage of optical elements. In each section, the characteristics and principles of the optical components are briefly explained. Then, their recent applications addressing the limitations of the conventional AR/VR displays are introduced.

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“…When the incident angle reaches or exceeds a critical angle, the incident light will be reflected back without refraction, which is called the total internal reflection (TIR) of light. According to the principle of TIR in geometric optics, the light produces TIR at the interface between the waveguide and the air and forms the necessary conditions for the light to be bounced inside the waveguide and propagated forward without exiting the waveguide, as shown in Figure 6 [61]. In virtue of the waveguide transmission mode, the display and imaging system can be moved away to the top of the forehead or the ear side of observer, which greatly reduces the obstruction of the optical system to the outside view, and makes the weight distribution more ergonomic, thus improving the wearing experience of the device [62][63][64].…”

Section: Waveguide Opticsmentioning

confidence: 99%

“…When the light travels to the out-coupler, the condition of TIR is broken and the light is coupled out to human eyes. The virtual images The layout of the waveguide [61].…”

Section: Diffractive Waveguidementioning

confidence: 99%

Advancements in Optical See-through Near-Eye Display

Zhang¹,

Zhou²

2023

Modern Development and Challenges in Virtual Reality

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With the development of optical design and manufacturing, the optical see-through near-eye display becomes a promising research topic in recent decades, which can be applied in medical devices, education, aviation, entertainment et al. Typical products include Head-mounted Displays (HMDs) and Augmented Reality (AR) glasses. The optical display system of AR devices mainly consists of a miniature projecting module and an optical imaging module. In this chapter, the display systems used by AR glasses on the market, including various mini-display screens and optical imaging elements, have been systematically summarized. Therein, the differences in optical combinators are the key part to distinguish various AR display systems. Thus, it is essential to figure out the advantages and disadvantages of each optical imaging technology applied in this area. Besides, the characteristics of the projectors are crucial to the quality of the images.

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Design of a large field-of-view two-dimensional geometrical waveguide

Cited by 6 publications

References 6 publications

Waveguide-based augmented reality displays: perspectives and challenges

Waveguide-based augmented reality displays: perspectives and challenges

Recent Applications of Optical Elements in Augmented and Virtual Reality Displays: A Review

Advancements in Optical See-through Near-Eye Display

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