Improving light output by micro-TiO2 scatters in pc-WLED encapsulants.

Phosphor-converted white light emitting diodes (pc-WLEDs) are used worldwide for an extensive amount of applications. The device is a complex combination of various components that introduce various technical issues: materials, electrical, chemical, thermal, and so on. All of these combined to obtain a targeted optical characteristic. While most of the pc-WLEDs are sufficient for basic illumination performance, there are still many issues to improve the pc-WLED performance. In this work, we deal with the incorporation of micron size particles of titanium oxide (TiO2) in silicone encapsulant that contains yttrium aluminum garnet (YAG) phosphor in remote phosphor pc-WLED. Based on the light output and the scattering spatial distribution measurements of the phosphor plates, we have found that several essential performance indices, like the color uniformity, the efficiency, and the amount of phosphor for the pc-WLEDs, can be adjusted by tuning the amount of TiO2 particles and thus be optimized. With a comprehensive model using a Monte-Carlo ray tracing process combined with the Mie scattering theory, two TiO2 loading conditions are revealed. The first one is the sparse condition that the TiO2 particles act as the scattering particles such as to increase the output flux to improve the efficiency of YAG. The second one is the dense condition that the TiO2 particles act more as barrier particles such so to decrease the output flux.

Single reflector design for integrated low/high beam meeting multiple regulations with light field management.

This paper proposed an effective multi-objective design procedure, called light field management, for a single multi-segment reflector that can simultaneously project low beams and high beams for bicycle and e-bike applications. Furthermore, two different regulations can be met, including the K-mark and the ECE Class B regulations. Through light field management, the etendue and flux density of each segment can be effectively managed, so that the design successfully meets the multiple regulations. In the experimental verification, two mockup samples including a plastic reflector with aluminum coating and an aluminum reflector were fabricated to verify the validity of the design. The experiment showed that the contrast across the cutoff line reached 100 and above, where the brightest point for low beams reached 200 lux and the whole pattern reached 250 lux. The supreme behavior of the head lamp shows that the proposed design procedure is valuable and helpful to an optical designer.

Reduction of phase error on phase-only volume-holographic disc rotation with pre-processing by phase integral.

In this paper, we present a study of observation of phase error of a volume holographic storage disc during the reading process when the disc is rotated or displaced in the theoretical calculation and the corresponding experiment. This additional phase error will dramatically decrease the bit error rate of a phase-only signal, even applying double-frequency shearing interferometry to retrieve the stored phase signal. Then we propose a novel approach to solve the problem. The stored signal is pre-processed by phase integral along the shearing direction so that applying the integral process to decode the phase signal is not necessary in the readout process. The proposed approach effectively reduces the error in phase retrieval and will be useful when applying double-frequency shearing interferometry in the readout process for volume holographic storage.

Optical servo with high design freedom using spherical-wave Bragg degeneracy in a volume holographic optical element.

A novel optical sensor is proposed and demonstrated with the use of spherical-wave Bragg degeneracy of a volume holographic optical element. Bragg degeneracy can be performed perfectly for a volume hologram written by two plane waves or spherical waves. But only spherical reference light is useful to perform severe shifting selectivity in one direction and Bragg degeneracy in another direction. The experiment corresponding to theoretical simulation was demonstrated in a volume holographic optical element, which was an optical servo for a collinear volume holographic disc. Through clever design, the displacement response of the tracking beam was observed for a magnification magnitude of 980% to the displacement of the probe beam so that the resolution requirement of the photosensor can be reduced. Besides, a high linearity of the displacement response was observed. To discover the design freedom, a theoretical study of the displacement response was done for the servo by two spherical waves. The linearity, the magnification magnitude, and the diffraction efficiency were examined and the property of the Bragg degeneracy was figured out.

Impact of multi-disciplinary treatment strategy on systolic heart failure outcome.

BACKGROUND: Patients with reduced ejection fraction have high rates of mortality and readmission after hospitalization for heart failure. In Taiwan, heart failure disease management programs (HFDMPs) have proven effective for reducing readmissions for decompensated heart failure or other cardiovascular causes by up to 30%. However, the benefits of HFDMP in different populations of heart failure patients is unknown. METHOD: This observational cohort study compared mortality and readmission in heart failure patients who participated in an HFDMP (HFDMP group) and heart failure patients who received standard care (non-HFDMP group) over a 1-year follow-up period after discharge (December 2014 retrospectively registered). The components of the intervention program included a patient education program delivered by the lead nurse of the HFDMP; a cardiac rehabilitation program provided by a physical therapist; consultation with a dietician, and consultation and assessment by a psychologist. The patients were followed up for at least 1 year after discharge or until death. Patient characteristics and clinical demographic data were compared between the two groups. Cox proportional hazards regression analysis was performed to calculate hazard ratios (HRs) for death or recurrent events of hospitalization in the HFDMP group in comparison with the non-HFDMP group while controlling for covariates. RESULTS: The two groups did not significantly differ in demographic characteristics. The risk of readmission was lower in the HFDMP group, but the difference was not statistically significant (HR = 0.36, p = 0.09). In patients with ischemic cardiomyopathy, the risk of readmission was significantly lower in the HFDMP group compared to the non-HFDMP group (HR = 0.13, p = 0.026). The total mortality rate did not have significant difference between this two groups. CONCLUSION: The HFDMP may be beneficial for reducing recurrent events of heart failure hospitalization, especially in patients with ischemic cardiomyopathy. TRIAL REGISTRATION: Longitudinal case-control study ISRCTN98483065 , 24/09/2019, retrospectively registered.

Comparative Effectiveness of Different Nonsurgical Treatments for Patellar Tendinopathy: A Systematic Review and Network Meta-analysis.

PURPOSE: To investigate the functional improvement and pain reduction of different nonsurgical treatments for patellar tendinopathy (PT), a systematic review with network meta-analysis was performed. METHODS: Studies were comprehensively searched for without language restrictions in the CENTRAL, MEDLINE, EMBASE, Web of Science, Physiotherapy Evidence Database, and SPORTDiscus databases from inception to May 2018. Randomized controlled trials about nonsurgical treatments for PT were included. The outcome measurements were the Victorian Institute of Sports Assessment (VISA) scale and pain scores (such as the visual analog scale or Numerical Rating Scale). Study quality was evaluated using the Physiotherapy Evidence Database score. Direct comparisons were performed using pairwise meta-analysis, whereas network meta-analysis was performed using a frequentist method in a multivariate random-effects model. RESULTS: Eleven studies with 430 affected patellar tendons were included in the systematic review. The summary mean difference of improvement in the VISA scale versus the control group for corticosteroid injection was -23.00 (95% confidence interval [CI] -36.73 to -9.27), for leukocyte-rich platelet-rich plasma (LR-PRP) was 13.22 (95% CI 2.37-24.07), for focused extracorporeal shockwave therapy (ESWT) was -1.28 (95% CI -6.25 to 3.68), for radial ESWT was -6.68 (95% CI -20.20 to 6.84), for ultrasound was -0.70 (95% CI -11.23 to 9.83), for autologous blood injection was -0.60 (95% CI -9.30 to 8.10), for dry needling was 17.51 (95% CI -2.57 to 37.60), for topical glyceryl trinitrate was -0.90 (95% CI -13.07 to 11.27), and for skin-derived tendon-like cells was 10.40 (95% CI -1.59 to 22.39). LR-PRP (Surface Under the Cumulative Ranking curve [SUCRA] = 87.5%) or dry needling (SUCRA = 90.5%) was most likely to be ranked the best in terms of improvement on the VISA scale. Compared with the control group, the summary mean difference of the change in pain score for corticosteroid injection was 0.80 (95% CI -3.48 to 5.08), for LR-PRP was -1.87 (95% CI -3.28 to -0.46), for focused ESWT was 0.13 (95% CI -0.68 to 0.93), for radial ESWT was 0.03 (95% CI -1.92 to 1.98), for ultrasound was -0.20 (95% CI -1.49 to 1.09), for autologous blood injection was 0.60 (95% CI -0.73 to 1.93), for dry needling was -0.37 (95% CI -2.71 to 1.97), and for topical glyceryl trinitrate was -0.50 (95% CI -2.55 to 1.55). The treatment most likely to be ranked the best in terms of change in pain score was LR-PRP (SUCRA = 94.9%). CONCLUSIONS: The network meta-analysis demonstrated that LR-PRP has the greatest functional improvement and pain reduction for PT compared with other treatment options. However, the treatment effect estimates can be biased by the possible intransitivity and should not be overestimated. LEVEL OF EVIDENCE: Level I, meta-analysis of Level I studies.

Ultrasonography has high positive predictive value for medial epicondyle lesions among adolescent baseball players.

PURPOSE: Only few studies have investigated medial epicondyle (MEC) lesions, particularly in the 12-18 age group. To the best of our knowledge, no study has compared ultrasonography (US), radiography and magnetic resonance imaging (MRI) in detecting MEC lesions. The aims of this study were to examine the value of US for detecting MEC lesions and to investigate correlations among diagnostic tools. METHODS: A prospective, comparative study was performed. Young baseball players from southern Taiwan were recruited, and basic characteristics, as well as passive range of motion (pROM) of the upper extremities, were recorded. Screening US was performed to identify MEC lesions, and players with MEC lesions received follow-up plain radiography and MRI. RESULTS: A total of 299 young baseball players were screened using US, and 28 of 299 players with possible MEC lesions were identified with a positive predictive value (PPV) of 88% according to MRI findings. The MEC lesions were primarily comprised of unfused ossicles and bony fragmentation. Other diagnoses, including UCL strain and medial epicondylitis, were also found by MRI in players with abnormal US screening results. The pROM of shoulder external rotation (ER) of the throwing hand was significantly reduced in players with MEC lesions (p = 0.006). CONCLUSIONS: Bony cortical discontinuity or fragmentation over the MEC warrants further research, and US provides good PPV for types of MEC lesions. Decreased shoulder ER may relate to MEC lesions and should be taken into consideration. The use of US may facilitate early detection and intervention. LEVEL OF EVIDENCE: IV, Cross-sectional study.

Effectiveness of ultrasonography screening and risk factor analysis of capitellar osteochondritis dissecans in adolescent baseball players.

BACKGROUND: Capitellar osteochondritis dissecans (COCD) is a common elbow injury in young baseball athletes. It may be asymptomatic at the early stage and may progress if left untreated. This study investigated the effectiveness of ultrasonography (US) screening for COCD in adolescent baseball players and identified risk factors of COCD. METHODS: A cross-sectional analysis study was conducted among baseball athletes aged 12 to 18 years. US screening of the throwing elbow was performed in all participants, and additional magnetic resonance imaging (MRI) was arranged for those with abnormal screening results. The prevalence of COCD was calculated according to MRI results. The US findings were compared with MRI findings. Data for characteristics, joint range of motion, and quality of pain were collected and analyzed using a logistic regression model to identify the risk factors of COCD. RESULTS: A total of 299 adolescent baseball players were screened, and 17 were found to have COCD according to US findings. MRI was performed in 15 of these 17 players, and the MRI findings further confirmed COCD in 10 players (66.7%). The presence of elbow pain while at rest, body height, and age at introduction to baseball were predictors of COCD. CONCLUSIONS: Although the effectiveness of diagnosing stage 1 COCD is satisfactory, US is a helpful tool for detecting stage 2 and higher-stage COCD. Elbow resting pain, lower body height, and introduction to baseball at a younger age are risk factors for COCD.

Analysis of a lens-array modulated coaxial holographic data storage system with considering recording dynamics of material.

In the first time, a simulation model with considering the recording dynamics of material is built and is used to simulate evolution of the grating strength of the recorded hologram in a coaxial volume holographic memory system. In addition, phase modulation by lens array in the reference is introduced and observed to perform better diffracted signal quality and higher shifting selectivity, in both simulation and experiment. The use of lens array is found to provide multiple advantages in volume holographic memory system. The new simulation model potentially can be used to precisely design the system to obtain higher diffracted signal quality, higher shifting selectivity, and reduction of M# consumption and increase of storage capacity.

Expanding color gamut of reflective liquid crystal displays from filtering undesirable wavelengths of a light source by an embedded etalon.

This work demonstrates a method to reduce the intensity of the undesirable wavelengths of blue (B-) and green (G-) ambient lights to expand the color gamut of reflective liquid crystal displays (LCDs) by an embedded etalon. The built-in reflector of the reflective LCDs is replaced by the blue-green overlapping wavelengths filtering etalon, which is used to reduce the intensity of undesirable B- and G-primaries, thereby decreasing the color cross talk of B- and G-color filters. After etalon adoption, the color gamut can be expanded from 105.96% to 121.81% of National Television System Committee (NTSC) in International Commission on Illumination (CIE) 1976 color space. Compared with the color gamut of the display without the blue-green overlapping wavelength etalon, the maximum expansion of color gamut is ∼15.85%. Moreover, the balance between light loss and color gamut expansion should be taken into consideration.

The Relationship between the Methylated Septin-9 DNA Blood Test and Stool Occult Blood Test for Diagnosing Colorectal Cancer in Taiwanese People.

BACKGROUND: Colorectal cancer (CRC) is a common and lethal disease in the world. There is an increasing number of cases in Taiwan and a higher rate at advanced stages. The immune fecal occult blood test (iFOBT) has been used as a screening method in Taiwan for years. A new novel diagnostic tool, the Methylated Septin-9 (MS-9) DNA blood test, had been reported to have high sensitivity and specificity for CRC detection. There are no available data in Taiwan, so we conducted this prospective randomized trial to investigate the relationship among the MS-9 DNA blood test, iFOBT, and a combination of the two tests for diagnosing CRC in Taiwanese people. METHODS: From July 1, 2012 to December 31, 2013, we prospectively selected 60 plasma samples from patients who were diagnosed with CRC and otherwise, the healthy group by colonoscopy in our hospital. Patients were divided into the CRC group and healthy group. CRC stages 0, I, II and stages III and IV were separately analyzed. We calculated the sensitivity and specificity of each group to determine the relationship among the MS-9 DNA blood test, iFOBT, and a combination of the two tests for diagnosing CRC in Taiwanese people. RESULTS: The results of the MS-9 DNA blood test for the 60 samples were divided into three groups, and the sensitivity as well as the specificity of the MS-9 DNA blood test to detect CRC were 47% and 89%, respectively. The results of iFOBT were also divided into three groups, and had higher sensitivity (84%) but lower specificity (55%) using iFOBT to detect CRC. Higher rates could be predicted to detect CRC if both the tests were positive. CONCLUSIONS: A combined MS-9 DNA blood test and iFOBT may help in a higher detection rate of CRC. It could be offered to individuals who are unwilling or unable to undergo colonoscopy. Further large prospective, randomized studies are needed in the future.

Evaluating posterior cruciate ligament injury by using two-dimensional ultrasonography and sonoelastography.

PURPOSE: This study aimed to elucidate the diagnostic criteria for posterior cruciate ligament (PCL) injury using ultrasonography. METHODS: Thirty-three patients with clinically suspected PCL injuries and 30 normal control subjects were recruited. Both groups were assessed using sonographic examination with reliability testing. Patients also underwent posterior stress radiography and magnetic resonance imaging (MRI). PCL thickness on two-dimensional ultrasonography (2D US), pixel intensity on sonoelastography, displacement on posterior stress view, and severity grading using MRI were analysed. Receiver operating characteristic (ROC) curves were plotted using MRI as the gold standard. Correlation coefficients among variables were calculated. RESULTS: Good to excellent reliabilities were noted for 2D US and red pixel intensity on sonoelastography. In injured knees, PCL thicknesses were significantly greater, and red pixel intensities were significantly lower, compared to non-injured knees of patients and healthy controls. This indicates increased swelling and softness in injured PCLs. The area under the PCL thickness ROC curve was 0.917 (p < 0.001), and the best diagnostic criterion was a thickness ≥6.5 mm (90.6 % sensitivity and 86.7 % specificity). Thickness correlated with red pixel intensity, International Knee Documentation Committee examination grade, and MRI severity grading. In addition, effusions were detected on 2D US in all knees with "tears" of other structures on MRI. CONCLUSIONS: 2D US is a useful tool to diagnose PCL injury, and PCL thickness ≥6.5 mm is the recommended diagnostic criterion. LEVEL OF EVIDENCE: II.

Effect of chip spacing on light extraction for light-emitting diode array.

GaN LED array in packaging is important for the demand of high optical flux. In order to tighten the whole packaging size, the spacing among LED chips becomes an important factor in the packaging design. This study is to investigate the change of the light extraction when a GaN LED chip array packaging is applied. The shielding effect with various spacing for the GaN LED array with or without silicon encapsulation is obtained. We apply the Monte Carlo ray-tracing method in the simulations to analyze the optical behavior of the two major types of the GaN LED array. The shielding effect is more dominant for bare chip packaging. When a silicone thin dispensing layer is applied, the shielding effect is not obvious because of more light extraction, the neighbor dies play an important role in photon recycling.

Study of temperature distributions in pc-WLEDs with different phosphor packages.

Phosphor converted white LEDs (pc-WLED) with different geometries, namely remote-dome, remote-plate, half-dome, and conformal-coating packages, were studied using simulations to obtain the thermal power and the temperature distribution. The results of an experiment carried out to measure the temperature distribution in these pc-WLEDs validate the simulation results. A hotspot always occurs in the phosphor region. The conformal-coating package is the most feasible choice to reduce the hotspot temperature comparing with the other geometries.

Optical design of dental light with high performance and low power based on white LEDs.

This paper presents an optical design of a dental light that meets the regulation of ISO 9680. The designed light pattern on the target is an elliptical shape with uniform illumination. Moreover, the real module contains four optical modules, and is operated at 9 W and performs a maximum illuminance of 42,010 lx. In order to reduce the correlated color temperature (CCT) variation, we replace the original white light-emitting diode with a new one, which has an extremely low angular CCT derivation. Accordingly, the CCT variation is reduced to 232 K from 1323 K of the original module.

A polarization control system for intensity-resolved guided mode resonance sensors.

In this study, a polarization-control setup for intensity-resolved guided mode resonance sensors is proposed and demonstrated experimentally. The experimental results are in good agreement with the simulation data based on rigorous coupled wave approach calculations. The proposed intensity-resolved measurement setup transfers polarization ellipses, which are produced from guided mode resonance to a linear polarization state under a buffer solution condition, and then suppresses the signals to dark using a polarization-control set. Hence, any changes in the refractive index results in an increase in the intensity signals. Furthermore, no wavelength-resolved or angular-resolved measurement is needed in this scheme. According to the experimental results, a wide linear detection range of 0.014 refractive index units is achieved and the limit of detection is 1.62E-4 RIU.

Color gamut characteristics of diffractive-light guides of near-eye augmented reality glasses.

We delve into the distinctive color gamut characteristics resulting from color dispersion of surface relief grating (SRG) and wavelength degeneracy of volume holographic optical element (VHOE) in a diffractive light guide. While a laser-like spectrum achieves an impressive 194% sRGB color gamut for both cases, it proves unsuitable for VHOE light guides due to limitations in breaking the field of view (FOV) of the display. Conversely, a broad-band light source, such as LEDs, offers continuous FOV but reduces the common color gamut to 50% sRGB. We then present a newly designed VHOE light guide capable of achieving the common color gamut of 130% sRGB using two multiplexed holograms of each color, closely matching the 133% sRGB achieved by an SRG light guide. This article presents the first theoretical methodology to elucidate color performance of diffractive light guides utilizing VHOEs with holographic multiplexing, affirming their suitability for crafting high-quality near-eye display.

Passive anti-leakage of blue light for phosphor-converted white LEDs with crystal nanocellulose materials.

A phenomenon known as "blue-light leakage" caused by overheating pcW-LEDs has recently been identified, and it poses a risk to users. This study focuses on investigating and optimizing a solution to address this issue. To tackle the problem of overheating and blue light leakage, we explored the application of a specific thermochromic material called crystal nano cellulose (CNC). We introduced CNC inside the epoxy lens of white LEDs. Importantly, under standard conditions, CNC has a negligible impact on the optical properties of the output white light. However, when overheating conditions arise, leading to blue light leakage, the temperature increase triggers a darkening effect in CNC. This thermochromic behavior of CNC allows it to strongly absorb the blue light, resulting in a significant suppression of the output luminous flux. As a result, the lamp dims, which not only prevents the user's eyes from being exposed to harmful bluish light but also serves as an indicator of aging in the pcW-LED. By implementing CNC as a responsive material in the design of white LEDs, this study offers a practical and effective solution to mitigate the negative effects of blue-light leakage caused by overheating. This improvement enhances the safety and comfort of users while also providing an early warning system for the aging of pcW-LEDs.

Hyperspectral screen-image-synthesis meter with scattering-noise suppression.

The screen image synthesis (SIS) meter was originally proposed as a high-speed measurement tool, which fused the measured data from multiple sample-rotational angles to produce a whole-field measurement result. However, it suffered from stray light noise and lacked the capability of spectrum measurement. In this study, we propose an SIS system embedded with a snapshot hyperspectral technology, which was based on a dispersion image of the sparse sampling screen (SSS). When a photo was captured, it was transformed and calibrated to hyperspectral data at a specific sample-rotational angle. After the hyperspectral data in all sample-rotational angles were captured, an SIS image-fusion process was then applied to get the whole field hyperspectral data. By applying SSS to the SIS meter, we not only create a screen image synthesis hyperspectral meter but also effectively address the issue of stray-light noise. In the experiment, we analyze its correctness by comparing the hyperspectral value with a one-dimensional spectrum goniometer (ODSG). We also show the 2D color temperature coefficient distribution and compare it with the ODSG. Experimental results also demonstrate the feasibility in terms of both spectrum distribution meter and color coefficient temperature distribution meter.

Sensitive metal layer assisted guided mode resonance biosensor with a spectrum inversed response and strong asymmetric resonance field distribution.

In this paper, a metal layer assisted guide mode resonance (MaGMR) device with high sensitivity is proposed for bioanalytical applications and its functioning is experimentally proved. We find that the reflection spectra present a unique inversed response. The resonance mechanism is also discussed. Numerical calculation results indicate that the high sensitivity performance of MaGMR comes from the strongly asymmetric resonance modal profile and low propagation angle inside the waveguide. There is a one-fold enhancement of the evanescent wave in the analytes region compared to typical GMR. According to the experimental results, the proposed MaGMR achieved a bulk sensitivity of 376.78 nm/RIU in fundamental TM mode resonating at 0.809 µm with the first diffraction angle. Experiment results show a 264.78% enhancement in the sensitivity compared to that of the typical GMR sensor in the same resonance conditions of TM mode.