Large Color Research Articles

Importance of Eco-Friendly OLED Lighting

The importance of artificial light has long been recognized as it extends the day. Copious corporations and academic institutions are investing cosmic treasures in tracking down the advanced artificial lighting applications with a vision towards energy efficient and eco-friendly solid state lighting. In this regard, organic light-emitting diodes (OLEDs) are going to change the human lifestyle, by offering a promising avenue to develop future energy saving solid-state lighting sources because of their intrinsic characteristics such as low driving voltage, high resolution, high brightness, large viewing angle, large color gamut, high contrast, less weight and size, efficiency etc., there by dictating their ability to reach the pinnacle in the field of flat panel displays and solid state lighting sources. With the goal towards future application, many design strategies like synthesis of novel materials, well judged anatomy of device configuration, development of refined and low cost fabrication techniques have been put forward to achieve high efficiency, good color stability and quality lighting. Practical applications, which enrich the ideas of the specialists in this field to develop new routes for future research development of OLEDs are enumerated and illustrated by specific examples. This chapter also integrates the novel approaches for energy efficient and eco-friendly solid state lighting as well as the limitations and global haphazards of currently used lighting systems. The current state of the art, ongoing challenges and future perspectives of this research frontier to reduce the driving voltage, minimization of degradation issues, enhance their life time are illustrated. Review on the status and future outlook of these OLEDs strongly reveals their emergence in the next few years.

Trivalent Graphs, Volume Conjectures and Character Varieties

The generalized volume conjecture and the AJ conjecture (a.k.a. the quantum volume conjecture) are extended to \({U_q(\mathfrak{sl}_2)}\) colored quantum invariants of the theta and tetrahedron graph. The \({\mathrm{SL}(2,\mathbb{C})}\) character variety of the fundamental group of the complement of a trivalent graph with E edges in S 3 is a Lagrangian subvariety of the Hitchin moduli space over the Riemann surface of genus g = E/3 + 1. For the theta and tetrahedron graph, we conjecture that the configuration of the character variety is locally determined by large color asymptotics of the quantum invariants of the trivalent graph in terms of complex Fenchel–Nielsen coordinates. Moreover, the q-holonomic difference equation of the quantum invariants provides the quantization of the character variety.

P‐39: A Novel Color Gamut Quantization Method for Wide Color Gamut Display

AbstractIn this paper, we propose a novel method to calculate the color gamut especially for wide color gamut display. The features of the proposed method are 1) luminance consideration, 2) large color space and 3) distinguishable color by human eyes.

12.1: Invited Paper: Quantum Dots: The Ultimate Down‐Conversion Material for LCD Displays

AbstractAssuming large color gamut and therefore better color reproducibility will be a highly desired feature of all displays as we look to the near future, we make the case in this paper that Quantum Dots (QDs) are currently the down‐conversion technology of choice that will allow liquid crystal display (LCD) makers to cost‐effectively reach and exceed 100% of the NTSC (National Television Standard Committee) standard while achieving maximum system efficiency. We will discuss in detail the numerous fundamental advantages of QDs over phosphors, along with their scientific origins, and make the case that QDs are the ultimate light generating material for next‐generation displays.

19.1: Invited Paper: Illuminating the Value of Larger Color Gamuts for Quantum Dot Displays

AbstractQuantum dot technology offers the promise of efficient and relatively inexpensive liquid crystal displays (LCDs) with large color gamuts (∼115% NTSC u'v'). Now, for the first time, a variety of high color performance devices are on the immediate horizon for applications ranging from 3“ diagonal hand held smart phones to +85” diagonal TVs . While people clearly prefer color displays, the relative value of different color reproduction systems remains an open question. Here we review how quantum dots enable high color performance and some of the advantages of large color gamut displays.

Nonpolarizing color mirrors on a high-reflecting metal base.

Optically variable devices made from optical-interference coatings create chromatic color mirrors that have minimal polarization differences with increasing incidence angle. These metal-dielectric-metal designs produce narrowband, high reflectance in the visible wavelength region. Broader-band reflectance regions, similar to those created by multilayer dielectric stacks, can be replicated on a high-reflecting metal base such as aluminum, maintaining the same nonpolarizing effects of the narrowband designs. These designs are intended for reflective systems used for display where reduced angle sensitivity is paramount. However, these designs can also be adapted for large angular-dependent color shift, such as in effect pigments. Design examples and layer material suggestions are given depending on the application requirements.

Demonstration of a broad band spectral head-mounted display with freeform mirrors

It has been demonstrated that electrical stimulation of the retina can produce visual perception for blind patients suffering from macular degeneration and retinitis pigmentosa. In order to let the retinal chip generate enough electrical stimulation, the near infrared ray source is added to enhance the stimulation current. However, it is a challenge to design a head-mounted display (HMD) that covers both visible and infrared rays. Since the HMD system covers such a broad spectral band, large color aberrations will be induced. In order to eliminate these large aberrations, a mirror system is adopted that will create a no color aberration system. We also use two freeform mirrors (FFMs) to reduce residual aberrations such as spherical aberrations and coma. The FFMs serve as the near-eye viewing optics that magnifies the image which is displayed through a microdisplay. Based on a 0.61 in. microdisplay, the HMD system demonstrates a diagonal field of view (FOV) of 30 degree and an f/# of 3.75, with an exit pupil diameter of 8 mm and eye clearance of 15mm.

Illuminant estimation for color constancy: why spatial-domain methods work and the role of the color distribution.

Color constancy is a well-studied topic in color vision. Methods are generally categorized as (1) low-level statistical methods, (2) gamut-based methods, and (3) learning-based methods. In this work, we distinguish methods depending on whether they work directly from color values (i.e., color domain) or from values obtained from the image's spatial information (e.g., image gradients/frequencies). We show that spatial information does not provide any additional information that cannot be obtained directly from the color distribution and that the indirect aim of spatial-domain methods is to obtain large color differences for estimating the illumination direction. This finding allows us to develop a simple and efficient illumination estimation method that chooses bright and dark pixels using a projection distance in the color distribution and then applies principal component analysis to estimate the illumination direction. Our method gives state-of-the-art results on existing public color constancy datasets as well as on our newly collected dataset (NUS dataset) containing 1736 images from eight different high-end consumer cameras.

A Hill Cipher Modification Based on Eigenvalues Extension with Dynamic Key Size HCM-EXDKS

All the proposed Hill cipher modifications have been restricted to the use of dynamic keys only. In this paper, we propose an extension of Hill cipher modification based on eigenvalues HCM-EE, called HCM-EXDKS. The proposed extension generating dynamic encryption key matrix by exponentiation that is made efficiently with the help of eigenvalues, HCMEXDKS introduces a new class of dynamic keys together with dynamically changing key size. Security of HCMEXDKS is provided by the use of a large number of dynamic keys with variable size. The proposed extension is more effective in the encryption quality of RGB images than HCM-EE and Hill cipher-known modifications in the case of images with large single colour areas and slightly more effective otherwise. HCM-EXDKS almost has the same encryption time as HCM-EE, and HCMHMAC. HCM-EXDKS is two times faster than HCM-H, having the best encryption quality among Hill cipher modifications compared versus HCM-EXDKS.

MEMS Laser Scanners: A Review

Laser scanners have been an integral part of MEMS research for more than three decades. During the last decade, miniaturized projection displays and various medical-imaging applications became the main driver for progress in MEMS laser scanners. Portable and truly miniaturized projectors became possible with the availability of red, green, and blue diode lasers during the past few years. Inherent traits of the laser scanning technology, such as the very large color gamut, scalability to higher resolutions within the same footprint, and capability of producing an always-in-focus image render it a very viable competitor in mobile projection. Here, we review the requirements on MEMS laser scanners for the demanding display applications, performance levels of the best scanners in the published literature, and the advantages and disadvantages of electrostatic, electromagnetic, piezoelectric, and mechanically coupled actuation principles. Resonant high-frequency scanners, low-frequency linear scanners, and 2-D scanners are included in this review.

Detection of large color variation in the potentially hazardous asteroid (297274) 1996 SK

Low-inclination near-earth asteroid (NEA) (297274) 1996 SK, which is also classified as a potentially hazardous asteroid, has a highly eccentric orbit. It was studied by multi-wavelength photometry within the framework of an NEA color survey at Lulin Observatory. Here, we report the finding of large color variation across the surface of (297274) 1996 SK within one asteroidal rotation period of 4.656 ± 0.122 hours and classify it as an S-type asteroid according to its average colors of B — V = 0.767 ± 0.033, V — R = 0.482 ± 0.021, V — I = 0.801 ± 0.025 and the corresponding relative reflectance spectrum. These results might be indicative of differential space weathering or compositional inhomogeneity in the surface materials.

Energy Transfer and Tunable Luminescence of NaLa(PO3)4:Tb3+/Eu3+ under VUV and Low-Voltage Electron Beam Excitation

Series of NaLa(PO3)(4):Tb3+/Eu3+ phosphors were prepared by a hightemperature solid-state reaction technique. Structure refinements were performed based on powder X-ray diffraction (XRD) data. VUV-UV-vis photoluminescence (PL), fluorescence decays, time-resolved emission spectra (TRES), and low-voltage cathodoluminescence (CL) spectra were utilized to investigate the luminescence and energy transfer processes. Under VUV-UV light and low-voltage electron beam excitation, NaLa(PO3)(4):Tb3+ and NaLa(PO3)(4):Eu3+ exhibit characteristic emissions of Tb3+ (D-5(4) --> F-7(J)) and Eu3+ (D-5(0) --> F-7(J)), respectively. By adjusting the doping concentration of Eu3+ ions in NaTb0.70La(0.30-x)Eux(PO3)(4), tunable emission colors are realized in a large color gamut, in which energy transfer from Tb3+ to Eu3+ was observed and discussed in detail. On the basis of the good VUV-vis PL and CL properties, NaLa(PO3)(4):Tb3+/Eu3+ phosphors might be promising for applications in plasma display panels (PDPs) and field emission displays (FEDs).

Total mesorectal excision: open, laparoscopic or robotic.

Goals Total mesorectal excision (TME) is the gold standard technique for the surgical treatment of rectal cancer. Despite the benefits of minimally invasive surgery, laparoscopic TME (LTME) is a technically challenging procedure with a long learning curve. Robotic TME (RTME) has been advocated as an alternative to conventional LTME, but large studies supporting the efficacy or RTME are scarce. This work will review the current literature on minimally invasive surgery for rectal cancer and discuss future directions in the field. Methods A review of recent large single and multicenter studies on minimally invasive surgery for rectal cancer was conducted. Results Based on two large randomized clinical studies (CLASICC (Green et al. 2013) and COLOR II (van der Pas et al. 2013)). LTME is safe and feasible for the treatment of rectal cancer. Compared to open surgery, LTME has been shown to result in superior postoperative outcomes and similar oncologic results. However, the conversion rate of LTME is around 17%. The literature supporting RTME is more limited. Robotic rectal resection appears to have similar postoperative and oncologic outcomes compared to LTME. RTME results in higher costs and possibly lower conversion rates. A large randomized clinical trial (ROLARR) comparing robotic to laparoscopic surgery for rectal cancer is underway. Conclusions Despite the technical challenges, current data supports the use of minimally invasive technique for rectal cancer surgery with superior short-term outcomes compared to an open approach. The use of robotic surgery is promising, but still limited and awaiting the conclusion of randomized clinical trials.

First whale fall chaetopterid; a gigantic new species of Phyllochaetopterus (Chaetopteridae: Annelida) from the deep sea off California

Phyllochaetopterus gigas, new species, was found living associated with a whale fall lying at 2892 meters depth in the Monterey Submarine Canyon, off California, U.S.A. The new species was found over a period of nine yr adjacent to, on, or in sediment lying over, the baleen of the whale fall. Phyllochaetopterus gigas is characterized by its large size (up to 30 cm preserved body length), long palps, coloration, and patterning of the ventral shield of the anterior region (region A), the presence of 4–6 large cutting chaetae on each parapodium of the fourth chaetiger (a4), the shape of these chaetae (with a pear-shaped head, some small lateral teeth on the edge), and presence of two middle-region (region B) chaetigers with foliose notopodia. The new species is compared to other Phyllochaetopterus species and appears to be, at least in part, a deposit feeder.

Hydrothermal synthesis, electronic structure and tunable luminescence of single-phase Ca5(PO4)3F:Tb3+,Eu3+microrods

Uniform and well-crystallized calcium fluorapatite [Ca5(PO4)3F, FAP] microrods have been successfully synthesized by a facile one-step hydrothermal synthesis method using sodium citrate as the crystal modifier. X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescent excitation spectra (PLE) and decay studies were employed to characterize the samples. The electronic structure and orbital population of FAP were also determined by means of density functional theory calculations. Under ultraviolet irradiation, the FAP:Tb(3+),Eu(3+) samples exhibit a blue-light emission of the host matrix, as well as the typical green emission band of the Tb(3+) ions, and a red-light emission of Eu(3+). The highly intense red emission bands of the Eu(3+) ions were attributed to the effective energy transfer from the Tb(3+) to Eu(3+) ions, which has been justified through the luminescence spectra and the fluorescence decay dynamics. The luminescence colors of FAP:Tb(3+),Eu(3+) microrods can be easily tuned by changing the concentration of Eu(3+) ions. The results reveal that the combination of the self-activated luminescence and rare earth-doping emission in FAP:Tb(3+),Eu(3+) microrods could result in tunable emission in a large color gamut, which can be used as a potential candidate for white-light-emitting diodes and other display devices.

激光显示广角球幕投影镜头设计

Laser display has advantages of large color gamut,high degree of saturation,variable display screen size,no electromagnetic radiation etc.According to application requirements,a wide-angle laser projection lens using in dome-screen display system was researched and designed in this paper.White field and light power matching parameters of three primary colors of laser display were analyzed and calculated.Telecentric retrofocus structure was adopted.Spheric optical system of the projection lens was propitious to processing and testing.Distortion was controlled in design effectively.Aperture aberration was used to improve illumination of image edge of projection display and illumination uniformity.Focal length of system was 11.3mm.The F number was 2.5.Full field of the lens can reach 110°.The MTF was greater than 0.6at nyquist frequency in 90%field of view.Image illumination uniformity was better than 95%.Distortion was less than 1.5%.Chromatic aberration was less than 0.5pixel.Analysis results showed that the design idea and method presented in this paper was feasible,and it was suitable for application requirements.

Electrochromic active layers from ultrathin nanowires of tungsten oxide

Electrochromic devices have benefited from the use of nanocrystalline films of particles to improve upon coloration and bleaching times while simultaneously enabling the use of solution based film making processes. In this work, electrochromic properties of ultrathin nanowires of substoichiometric tungsten oxide deposited on ITO via electrophoretic deposition are studied. These films show large coloration changes with very rapid coloration and bleaching times of 4.1 and 2.9 seconds respectively for an optical density change of 0.58 using H+ as the charge-balancing ion. These fast switching times are due to the combination of fast diffusion of ions into the narrow diameter wires and density control of the film through the deposition process. We also show good film stability over 300 colour–bleach cycles. This development not only advances the potential of WOx films in display applications, but can also improve their performance in smart windows.

Post Deposition Annealing Temperature Effect on White-light Emitting of Sputter Deposited Zr-doped HfO2 Thin Film

ABSTRACTThe warm white light emission from the MOS capacitor containing the Zr-doped HfO2 high-k thin film on a p-type Si wafer under various post deposition annealing temperatures has been investigated. The light intensity is affected by the annealing temperature and the magnitude of the stress voltage. The annealing temperature changes the defect density and the physical thickness of the high-k stack. The high stress voltage induces the strong light emission because of the passage of a large current through the conductive path. The broad band emission spectrum covers the visible and near IR wavelength range with a large color rendering index. This new light emission device has a very long lifetime of > 1,000 hours at the atmosphere without a protection layer. The device is made of the IC compatible material and fabrication process, which favors the application over a wide range of products.

Focus on software and data acquisition

Focus on software and data acquisition

Green orchid bee Euglossa dilemma Friese (Insecta: Hymenoptera: Apidae)

Green orchid bees are a quite conspicuous and charismatic species. This is mostly due to their large size and bright metallic-green coloration. They are very fast and agile flyers, and can be seen quickly darting from flower to flower separated by long periods of hovering. Male orchid bees collect fragrant volatile compounds from their environment and present them to females by fanning their wings and “spray ventilating” their bouquet for the inspection of prospective mates. In Florida, male green orchid bees are attracted to chemicals produced by certain wood-rot fungi, decomposing vegetation, perfume flowers, and certain essential oils such as clove and cinnamon oil. Male green orchid bees can be quickly and easily attracted and observed by soaking a small piece of paper with clove oil and placing it outside. This 4-page fact sheet was written by Aaron Mullins, and published by the UF Department of Entomology and Nematology, October 2013. http://edis.ifas.ufl.edu/in1013