Showing papers in "Journal of The Society for Information Display in 2020"

Vein detection with near‐infrared organic photodetectors for biometric authentication

Abstract: We combine a low dark current and high-detectivity near-infrared (NIR)-sensitive organic photodetector with a high-resolution 508 pixels per inch (ppi) oxide thin-film transistor (TFT) backplane to create a large-area thin NIR detector, using processes that are compatible with flat-panel display fabrication. The detector is characterized showing high uniformity and linearity. With the use of a NIR light source, the detector is capable of imaging the (pattern of) veins under the skin in reflection, leading to improved biometric authentication.

Chirped polarization volume grating for wide FOV and high‐efficiency waveguide‐based AR displays

Abstract: In the past few decades, augmented reality (AR) displays, such as Google Glass, Microsoft HoloLens, and Magic Leap One, have found interesting applications in areas such as education, health care, engineering, and gaming. To integrate the computer-generated (CG) images with see-through real-world environment, different types of optical combiners have been developed. For examples, the polarizing beam splitter (PBS) is used in traditional optical design, and the partial mirror and grating are widely used in waveguide design. Compared with the PBS approach, waveguide-based AR offers several attractive features, such as compact structure and lightweight. However, the limited field of view (FOV) remains a challenge. Holographic volume grating (HVG) and surface relief grating (SRG) are commonly used as the combiners to couple the imaging light into the waveguide. The angular response of the combiner is directly related to the FOV of the AR system. For HVG, the angular bandwidth is determined by the index contrast. On the basis of dichromated gelatin (a common material for HVG), the index contrast can reach as high as 0.15; however, the dichromated gelatin is environmentally sensitive and not suitable for commercial products. Thus, a more commonly used material for making HVG is a photopolymer having refractive index contrast of about 0.035, which results in a limited angular bandwidth (10 ). By applying multiplexing methods to HVG, wide angular bandwidth is achievable for some thick HVGs. In terms of SRG, due to the large index contrast between polymer and air, SRG can achieve a larger angular bandwidth than HVG; and this tilted-groove structure is achieved by nanoimprinting method in mass production. Similar to HVG, SRG also has to address the trade-off between angular bandwidth, diffraction efficiency, and manufacturing cost. As a result, the FOV of the waveguide-based AR products is still limited by the combiner and total internal reflection (TIR). Compared with HVG and SRG, reflective PVG based on liquid crystal materials exhibits unique characteristics in both optical properties and fabrication, such as nearly 100% first-order diffraction efficiency, high index contrast, large diffraction angle, and simple fabrication process. Therefore, extensive efforts have been attempted to applying reflective polarization volume grating (PVG) for waveguide coupling. To provide a promising solution of limited FOV in waveguide-based AR, here, we propose a reflective Received: 13 February 2020 Revised: 11 March 2020 Accepted: 12 March 2020

Influence of virtual objects' shadows and lighting coherence on distance perception in optical see‐through augmented reality

Abstract: This paper focuses on how virtual objects' shadows as well as differences in alignment between virtual and real lighting influence distance perception in optical see-through (OST) augmented reality (AR). Four hypotheses are proposed: (H1) Participants underestimate distances in OST AR; (H2) Virtual objects' shadows improve distance judgment accuracy in OST AR; (H3) Shadows with different realism levels have different influence on distance perception in OST AR; (H4) Different levels of lighting misalignment between real and virtual lights have different influence on distance perception in OST AR scenes. Two experiments were designed with an OST head mounted display (HMD), the Microsoft HoloLens. Participants had to match the position of a virtual object displayed in the OST-HMD with a real target. Distance judgment accuracy was recorded under the different shadows and lighting conditions. The results validate hypotheses H2 and H4 but surprisingly showed no impact of the shape of virtual shadows on distance judgment accuracy thus rejecting hypothesis H3. Regarding hypothesis H1, we detected a trend toward underestimation ; given the high variance of the data, more experiments are needed to confirm this result. Moreover, the study also reveals that perceived distance errors and completion time of trials increase along with targets' distance.

Advances in automotive interior lighting concerning new LED approach and optical performance

Abstract: Correspondence Karlheinz Blankenbach, Display Lab, Pforzheim University, Pforzheim, Germany. Email: kb@displaylabor.de Abstract Automotive interior lighting has to follow general trends in lighting and will therefore evolve toward hundreds and even thousands of RGB LEDs per car. Creating mood at day and night, pixelated sign-like information, and theaterlike effects like welcome and goodbye messages are examples for outstanding user experience. Furthermore, safety features such as warnings and driving state are a must for autonomous cars. It requires new concepts for the whole interior lighting system to reach premium quality such as data rate (beyond today's bus standard for lighting), support for safety rules, compensation of temperature effects, daylight performance (including huge dimming range for night drive), uniformity in terms of luminance and color along the light guide, and mixing of red, green, and blue (RGB) with white. We report a new automotive RGB light-emitting diode (LED) system that fulfills the above requirements and saves effort as well as cost by calibration before integration. Extensive studies were performed for daylight threshold evaluation with subjects and methods for judging on uniformity for direct-lit RGB light guides based on the contrast sensitivity function and Gaussian fit of the LED luminance profile.

Wide-view augmented reality display with diffractive cholesteric liquid crystal lens array

Abstract: Funding information Intel Corporation Abstract A novel augmented reality display is proposed to achieve a field of view of 100 , while maintaining a good form factor with a glass-thin waveguide combiner. The out-coupler consists of an array of off-axis diffractive lenslets with extremely low f-number. A breadboard system is built and its performance characterized, combined with analysis and discussion of further improvement.