Design, implementation and characterization of a quantum-dot-based volumetric display.
ABSTRACT: In this study, we propose and experimentally demonstrate a volumetric display system based on quantum dots (QDs) embedded in a polymer substrate. Unlike conventional volumetric displays, our system does not require electrical wiring; thus, the heretofore unavoidable issue of occlusion is resolved because irradiation by external light supplies the energy to the light-emitting voxels formed by the QDs. By exploiting the intrinsic attributes of the QDs, the system offers ultrahigh definition and a wide range of colours for volumetric displays. In this paper, we discuss the design, implementation and characterization of the proposed volumetric display's first prototype. We developed an 8 × 8 × 8 display comprising two types of QDs. This display provides multicolour three-type two-dimensional patterns when viewed from different angles. The QD-based volumetric display provides a new way to represent images and could be applied in leisure and advertising industries, among others.
Project description:Volumetric three-dimensional displays offer spatially accurate representations of images with a 360° view, but have been difficult to implement due to complex fabrication requirements. Herein, a chemically enabled volumetric 3D digital light photoactivatable dye display (3D Light PAD) is reported. The operating principle relies on photoactivatable dyes that become reversibly fluorescent upon illumination with ultraviolet light. Proper tuning of kinetics and emission wavelengths enables the generation of a spatial pattern of fluorescent emission at the intersection of two structured light beams. A first-generation 3D Light PAD was fabricated using the photoactivatable dye N-phenyl spirolactam rhodamine B, a commercial picoprojector, an ultraviolet projector and a custom quartz imaging chamber. The system displays a minimum voxel size of 0.68?mm<sup>3</sup>, 200??m resolution and good stability over repeated 'on-off' cycles. A range of high-resolution 3D images and animations can be projected, setting the foundation for widely accessible volumetric 3D displays.
Project description:In this study, a method to construct a full-colour volumetric display is presented using a commercially available inkjet printer. Photoreactive luminescence materials are minutely and automatically printed as the volume elements, and volumetric displays are constructed with high resolution using easy-to-fabricate means that exploit inkjet printing technologies. The results experimentally demonstrate the first prototype of an inkjet printing-based volumetric display composed of multiple layers of transparent films that yield a full-colour three-dimensional (3D) image. Moreover, we propose a design algorithm with 3D structures that provide multiple different 2D full-colour patterns when viewed from different directions and experimentally demonstrate prototypes. It is considered that these types of 3D volumetric structures and their fabrication methods based on widely deployed existing printing technologies can be utilised as novel information display devices and systems, including digital signage, media art, entertainment and security.
Project description:Fast signal processing and real-time displays are essential for practical imaging modality in various fields of applications. However, the imaging speed in optical-resolution photoacoustic microscopy (OR-PAM), in particular, depends on factors such as the pulse repetition rate of the laser, scanning method, field of view (FOV), and signal processing time. In the past, efforts to increase acquisition speed either focused on developing new scanning methods or using lasers with higher pulse repetition rates. However, high-speed signal processing is also important for real-time volumetric display in OR-PAM. In this study, we carried out parallel signal processing using a graphics processing unit (GPU) to enable fast signal processing and wide-field real-time displays in laser-scanning OR-PAM. The average total GPU processing time for a B-mode PAM image was approximately 1.35 ms at a display speed of 480 fps when the data samples were acquired with 736 (axial) × 500 (lateral) points/B-mode-frame at a pulse repetition rate of 300 kHz. In addition, we successfully displayed maximum amplitude projection images of a mouse's ear as volumetric images with an FOV of 3 mm × 3 mm (500 × 500 pixels) at 1.02 s, corresponding to 0.98 fps.
Project description:Semiconductor nanocrystals are rapidly spreading into the display and lighting markets. Compared with liquid crystal and organic LED displays, nanocrystalline quantum dots (QDs) provide highly saturated colors, wide color gamut, resolution, rapid response time, optical efficiency, durability and low cost. This remarkable progress has been made possible by the rapid advances in the synthesis of colloidal QDs and by the progress in understanding the intriguing new physics exhibited by these nanoparticles. In this review, we provide support to the idea that suitably engineered core/graded-shell QDs exhibit exceptionally favorable optical properties, photoluminescence and optical gain, while keeping the synthesis facile and producing QDs well suited for light emitting applications. Solid-state laser emitters can greatly profit from QDs as efficient gain materials. Progress towards fabricating low threshold, solution processed DFB lasers that are optically pumped using one- and two-photon absorption is reviewed. In the field of display technologies, the exploitation of the exceptional photoluminescence properties of QDs for LCD backlighting has already advanced to commercial levels. The next big challenge is to develop the electroluminescence properties of QD to a similar state. We present an overview of QLED devices and of the great perspectives for next generation display and lighting technologies.
Project description:Mechanofluorochromism (MFC) of molecular solids generally results from the variation of intermolecular interactions induced by external mechanical forces. However, the use of internal photomechanical forces to perturb intermolecular interactions for multicolour fluorescence responses has yet to be demonstrated. Herein we report a unichromophoric anthracene-pentiptycene derivative (1) that displays both MFC and photomechanofluorochromism (PMFC), which lead to various fluorescence colours including red-green-blue (RGB) and near-pure white-light emission. Compound 1 crystallizes in two polymorphs, the yellow (Y) and green (G) emissive forms, in which the pairwise stacked anthracene groups undergo [4 + 4] photodimerization to form the UV (black) emissive photodimer 2 and meanwhile exert photomechanical stresses on the neighbouring molecules. While the photomechanical stresses cause an excimer-to-monomer switching that results in a blue fluorescent state for the Y form, a red-emissive "super dimer" is photomechanically produced for the G form. The recovery of the Y form demands heating, but the G form could be restored by selective photoexcitation of the super dimer. X-ray crystal structures of the Y and G forms and the photodimer 2 generated through single-crystal-to-single-crystal transformation provide a clue to the origins of polymorph-dependent PMFC. The corresponding MFC and mechano-activated vapofluorochromism (VFC) of 1 also shed light on the structure-property relationship. The ability to spatially and temporally control the fluorochromicity of 1 is demonstrated by a series of multicolour fluorescence patterning of "angelfishes".
Project description:Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a significant positive association between UV reflectance and courtship displays. Among parrots (Psittaciformes), 68% of surveyed species have fluorescent plumage, and again there is a strong positive association between courtship displays and fluorescence. These associations are not artefacts of the plumage used in courtship displays, being generally more 'colourful' because there is no association between display and colours lacking UV reflectance or fluorescence. Equally, these associations are not phylogenetic artefacts because all results remain unchanged when families or genera, rather than species, are used as independent data points. We also find that, in parrots, fluorescent plumage is usually found adjacent to UV-reflective plumage. Using a simple visual model to examine one parrot, the budgerigar Melopsittacus undulatus, we show that the juxtaposition of UV-reflective and fluorescent plumage leads to a 25-fold increase in chromatic contrast to the budgerigar's visual system. Taken together, these results suggest that signals based on UV contrast are of special importance in the context of active sexual displays. We review briefly six hypotheses on why this may be the case: suitability for short-range signalling; high contrast with backgrounds; invisibility to predators; exploitation of pre-existing sensory biases; advertisement of feather structure; and amplification of behavioural signals.
Project description:A new generation of public displays demands high interactive and multiscreen features to enrich people's experience in new pervasive environments. Traditionally, research on public display interaction has involved mobile devices as the main characters during the use of personal area network technologies such as Bluetooth or NFC. However, the emergent Smart TV model arises as an interesting alternative for the implementation of a new generation of public displays. This is due to its intrinsic connection capabilities with surrounding devices like smartphones or tablets. Nonetheless, the different approaches proposed by the most important vendors are still underdeveloped to support multiscreen and interaction capabilities for modern public displays, because most of them are intended for domestic environments. This research proposes multiscreen interactive middleware for public displays, which was developed from the principles of a loosely coupled interaction model, simplicity, stability, concurrency, low latency, and the usage of open standards and technologies. Moreover, a validation prototype is proposed in one of the most interesting public display scenarios: the advertising.
Project description:Volumetric muscle loss (VML) resulting from extremity trauma presents chronic and persistent functional deficits which ultimately manifest disability. Acellular biological scaffolds, or decellularized extracellular matrices (ECMs), embody an ideal treatment platform due to their current clinical use for soft tissue repair, off-the-shelf availability, and zero autogenous donor tissue burden. ECMs have been reported to promote functional skeletal muscle tissue remodeling in small and large animal models of VML injury, and this conclusion was reached in a recent clinical trial that enrolled 13 patients. However, numerous other pre-clinical reports have not observed ECM-mediated skeletal muscle regeneration. The current study was designed to reconcile these discrepancies. The capacity of ECMs to orchestrate functional muscle tissue remodeling was interrogated in a porcine VML injury model using unbiased assessments of muscle tissue regeneration and functional recovery. Here, we show that VML injury incites an overwhelming inflammatory and fibrotic response that leads to expansive fibrous tissue deposition and chronic functional deficits, which ECM repair does not augment. Overall design: RNA-Seq time couse of muscle volumetric muscle loss injury healing with controls
Project description:An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20?wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs.
Project description:As molecular labels for cells and tissues, fluorescent probes have shaped our understanding of biological structures and processes. However, their capacity for quantitative analysis is limited because photon emission rates from multicolour fluorophores are dissimilar, unstable and often unpredictable, which obscures correlations between measured fluorescence and molecular concentration. Here we introduce a new class of light-emitting quantum dots with tunable and equalized fluorescence brightness across a broad range of colours. The key feature is independent tunability of emission wavelength, extinction coefficient and quantum yield through distinct structural domains in the nanocrystal. Precise tuning eliminates a 100-fold red-to-green brightness mismatch of size-tuned quantum dots at the ensemble and single-particle levels, which substantially improves quantitative imaging accuracy in biological tissue. We anticipate that these materials engineering principles will vastly expand the optical engineering landscape of fluorescent probes, facilitate quantitative multicolour imaging in living tissue and improve colour tuning in light-emitting devices.