MgCeAl11O19:Tb3+ and Mg8Ge2O11F2:Mn4+ in enhancing the color quality of remote phosphor LED

As the name infers, the triple-layer remote phosphor (TRP) has 3 phosphor layers includes the red Mg8Ge2O11F2:Mn4+ phosphor layer on the top, the green MgCeAl11O19:Tb3+ phosphor layer in the middle, and the yellow YAG:Ce3+ layer at the bottom and is mentioned as a solution to increase the chromaticity and luminescence adequacy of the white LEDs (WLEDs) in this article. As to control the red light for higher value achieve in the color rendering index (CRI), using red Mg8Ge2O11F2:Mn4+ phosphor in the TRP structure is recommended. All the outcomes indicate that when red phosphor Mg8Ge2O11F2:Mn4+ concentration grows the CRI gets higher values, and drastically declines when the concentration of green phosphor MgCeAl11O19:Tb3+ increases. As the same time, applying the green MgCeAl11O19:Tb3+ phosphor layer to manage the green light as it can make the luminous efficacy (LE) of WLEDs increase. In particular, the index of LE can also be improved over 40% by limiting the scatter of light and putting in green light. Moreover, to preserve the average correlated color temperature (ACCT) stable at 8500K, the yellow YAG:Ce3+ concentration must be cut down as the concentration of red and green phosphor rise

PRICING AND INVESTMENT STRATEGY FOR DIGITAL TECHNOLOGY IN A SUPPLY CHAIN

This study addresses the problem of the pricing and investment strategy for smart technology under a supply chain with one manufacturer and one retailer. The models are constructed to investigate the strategic choices of supply chain members for investing in digital/smart technology under three scenarios: the M–system, wherein only the manufacturer fully pays for the investment cost; the S–system, wherein the manufacturer and retailer share the investment cost; and the R–system, wherein the retailer fully pays for the investment cost. We formulate analytical models to determine the optimal wholesale price, retail price and investment strategy in a Stackelberg game setting. Our findings show that the S–system is the most appropriate choice for both the manufacturer and retailer. We also suggest the appropriate investment sharing ratio to achieve Pareto improvement under such an arrangement

The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote phosphor LED

Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce3+ under green phosphor YPO4:Ce3+,Tb3+ or red phosphor LiLaO2:Eu3+. After that, we search for suitable concentration of LiLaO2:Eu3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu3+, the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce3+,Tb3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu3+ and YPO4:Ce3+,Tb3+ over increase. Results are verified by Mie theory and Beer’s Law and can be applied to practical manufacturing of high quality WLEDs

The future of robotic-assisted laparoscopic surgery

Introduction: Since the first revolution of robotic-assisted surgery officially happened in 2000, the healthcare service worldwide has transformed into a new era due to its superior technological advancements, particularly in laparoscopic surgery. Da Vinci which is seen as a master-slave system and Kymerax which is categorized as a hand-held device are commonly used in robotic-assisted laparoscopic surgery. Whilst a conventional or open method requires a large incision to perform a surgery, laparoscopy - a minimally invasive surgery (MIS) is an advantageous surgical method which reduces an abdominal incision to a minimum, and effectively exploited with robots. Methods: Based on available articles with the object of robotic surgical surgery, two SWOT analysis for Da Vinci and Kymerax were formulated to understand strengths, weaknesses, opportunities and threats of each system in comparison with the traditional laparoscopic surgery. From that, the future outlook is anticipated based on the scientific background. Results: Alongside technological advantages of Da Vinci mainly known as 6-degree of freedom, dexterity enhancement, stereovision, tremor filtering and especially minimal invasive surgery, it still has disadvantages that are not neglectable such as huge investment and lack of haptic feedback. Although the malfunction rate of Da Vinci is not significantly high, surgeons should be aware of it to fix or alter instruments in time. Kymerax is not as advanced as Da Vinci but it can fill in the gap of the Da Vinci which includes thelarge investment and bulky instruments. The Kymerax is the low-cost hand-held device allowing multiple degrees of freedom. It is an optimal combination between traditional performance and robotic performance allowing surgeons to manipulate in their hands and ensure haptic feedback. Conclusions: Both Da Vinci and Kymerax systems offer superior benefits for medical service due to the ongoing technological growth. The cost-effectiveness of Da Vinci system is currently a problematic issue when medical institutions consider to install them. The surgical instruments market, however, has become highly competitive which is likely leading to the decline of the costly investments. In the digital world nowadays, it will be a promising future for more integrated medical inventions

The application of green YF3:Er3+,Yb3+ and red MgSr3Si2O8:Eu2+,Mn2+ layers to remote phosphor LED

White light-emitting diodes (WLEDs) with quantum dots (QDs) and phosphor have pulled in huge consideration because of their incredible shading rendering capacity. In the bundling procedure, a QDs film and a phosphor silicone layer will in general be isolated for lessening the reabsorption misfortunes and keeping the QDs surface molecules in a good condition. This examination explored the bundling succession of QDs and phosphor layers to the optical and warm exhibitions of WLEDs. The emitted optical power and PL spectra were estimated and dissected, while an infrared warm imager was utilized to reenact and approve tentatively the temperature fields. The results reveal that at 60 mA, WLEDs with green QDs-on-phosphor type accomplished lumen output (LO) of 1578 lm, with shading rendering record (CRI) of Ra = 60, while the red QDs-on-phosphor type WLEDs exhibited lower LO of 1000 lm, with Ra = 82. In addition, the QDs-onphosphor type WLEDs generated less warmth than the other, and as a result, the most noteworthy temperature in this packaged type was lower than the other. Additionally, its temperature contrast can arrive at 12.3°C. Along these lines, regarding bundling arrangement, the QDs-on-phosphor type is an ideal bundling design to better the optical productivity and shading rendering capacity, as well as lower gadget temperature

TiO2/silicone encapsulation film for achieving optical performance improvement of chip-on-board packaging LEDs

TiO2 nanoparticle and silicon composite has powerful effect of scattering, thus it is famous in enhancing the scattered light in light-emitting diode (LED) packages. To accomplish higher lighting performance in LED devices, a thin encapsulation layer of TiO2 with high concentration and silicon glue is introduced to complement the main encapsulation one. After conducting experiments, the results present that in the case of the main encapsulation including only silicone, the light extraction efficiency (LEE) of COB LEDs increases to 65%. On the other hand, when there is the additional layer of TiO2 and silicone, the improvement of LEE depends on the concentration of TiO2. As this nanoparticle concentration decreases from 0.12 to 0.035 g/cm3, the LEE can be enhanced from 6% to 24%. Moreover, at the average correlated color temperature (CCT) of approximately 8500 K, the layer of TiO2/silicone composite can help to accomplish the reduction of the angular correlated color temperature (CCT) deviation, from 900 to 470 K, within −90° to 90° viewing angle range

Acquiring higher lumen efficacy and color rendering index with green NaYF4:Er3+Yb3+ and red α-SrO·3B2O3:Sm2+ layers for designing remote phosphor LED

Lighting devices that apply diodes to create white light-emitting diodes (WLEDs) can achieve remarkable results in color quality, especially those containing quantum dots (QDs) and phosphor. The technique to create an appropriate package is providing spaces between the QDs and phosphor components which helps decrease the ratio of the reabsorption losses and keeps the QDs surface ligands constant. The research aims to perfect the constructing method of remote phosphor configuration containing quantum dots and phosphor materials that based on lighting properties and temperature feature of WLEDs. The infrared thermography is the tool to measure and analyze total emitted light and emission ranges of the device. This device is also used in temperature simulation and experimental verification. At the given mA of 60, the WLEDs structure with green QDs layer above the phosphor layer results in 996 lm luminous flux (LF), and Ra = 57 in color rendering ability. Meanwhile, luminous flux of WLEDs with red QDs-on-phosphor structure is 632, and Ra = 70. Furthermore, comparing with the green QDs-on-phosphor type, the red QDs-on-phosphor type emitted less LF. However, the red QDs-on-phosphor type can be the most effective package design to achieve color rendering ability

Improving optical properties of remote phosphor LED using green Y2O3:Ho3+ and red Mg4(F)(Ge, Sn)O6:Mn2+ layers

The lighting device that employs diodes to create white light (WLEDs) with quantum dots (QDs) and phosphor layers is a promising lighting method that is increasingly used in many fields on account of the remarkable color expressing ability. The QDs film is usually placed apart from the phosphor layer according to the packaging configuration to prevent light loss due to backscattering as well as preserve the consistency of the ligands on the QDs surface. The article also conducted experiments to compare the lighting properties and thermal output of the two packaging orders of QDs and phosphor. The heat discharing ranges were simulated with thermography technology, moreover, other parameters such as light energy emission and PL spectra are acquired to evaluate the efficiency of the packaging order. The results from the practical experiment show that while under 10% wt., the luminous output (LO) of green QDs-on-phosphor structure reaches 1130 lm, higher than the red QDs-on-phosphor structure with 878 lm, and the color rendering value in the configuration with red QDs on phosphor is Ra = 74 are higher than Ra = 68 index of the green QDs-on-phosphor structure. As a result, the QDs-on-phosphor is determined as the better packaging configuration to choose to achieve an overall improvement in lighting efficiency, color rendering inde

Enhancing light scattering effect of white LEDs with ZnO nanostructures

Pc-LEDs, the lighting method that blends blue LED light with yellow light from phosphor to discharge white radiation, is one of the most advance known for high lumen output. However, pc-LEDs has inferior due to angular CCT deviation, which prevent pc-LEDs from reaching better performance. As a result, this research is conducted to address the need of pc-LEDs development by introducing a configuration doped with ZnO nanoparticles. The finite-difference time-domain (FDTD) method and the phosphor layer containing ZnO were applied in the experiments. The effect of ZnO-filled on the performance of color quality pc-LEDs is confirmed through calculated results. In particular, the uniformity of scattered light is improved with the presence of ZnO. In addition, ZnO particles also minimize the deviation of color temperature and enhance the color quality. Although there is a small decline in lumen output to achieve better color temperature uniformity, however, with suitable concentrations such as 0.25% N-ZnO, 0.25% S-ZnO, and 0. 75% R-ZnO, the decline is acceptable. The research on ZnO pc-LEDs demonstrates that this affordable and simple configuration can improve lighting properties and create other directions to enhance white ligh