Physical design and assembly process development of a multichip package containing a light emitting diode (LED) array die

1997 ◽  
Vol 20 (4) ◽  
pp. 389-395 ◽  
Author(s):  
R. Bonda ◽  
Treliant Fang ◽  
K. Kaskoun ◽  
W.H. Lytle ◽  
B. Marlin ◽  
...  
Keyword(s):  
Process Development ◽  
Light Emitting Diode ◽  
Physical Design ◽  
Assembly Process ◽  
Light Emitting ◽  
Led Array

Miniaturized UV-LED Array Chip Photochemical Vapor Generator Coupled with Point Discharge Optical Emission Spectrometer for Determination of Trace Selenium

2021 ◽  
Author(s):  
Mengtian Li ◽  
Yi Luo ◽  
Zhirong Zou ◽  
Fujian Xu ◽  
Xiaoming Jiang ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Optical Emission ◽  
Nano Tio2 ◽  
Light Emitting ◽  
Uv Led ◽  
Led Array ◽  
Point Discharge ◽  
Photochemical Vapor Generation ◽  
Optical Emission Spectrometer

An ultraviolet light emitting diode (UV-LED) array chip as irradiation source for nano-TiO2 catalyzed photochemical vapor generation (PCVG) was combined with a hollow electrode point discharge microplasma optical emission spectrometer...

scholarly journals Real-Time Healthcare Data Transmission for Remote Patient Monitoring in Patch-Based Hybrid OCC/BLE Networks

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1208 ◽  
Author(s):  
Moh. Hasan ◽  
Md. Shahjalal ◽  
Mostafa Chowdhury ◽  
Yeong Jang
Keyword(s):  
Real Time ◽  
Light Emitting Diode ◽  
Health Condition ◽  
High Signal ◽  
Network Access ◽  
Light Emitting ◽  
Healthcare Data ◽  
Led Array ◽  
Access Request ◽  
Remote Patient

Research on electronic healthcare (eHealth) systems has increased dramatically in recent years. eHealth represents a significant example of the application of the Internet of Things (IoT), characterized by its cost effectiveness, increased reliability, and minimal human eff ort in nursing assistance. The remote monitoring of patients through a wearable sensing network has outstanding potential in current healthcare systems. Such a network can continuously monitor the vital health conditions (such as heart rate variability, blood pressure, glucose level, and oxygen saturation) of patients with chronic diseases. Low-power radio-frequency (RF) technologies, especially Bluetooth low energy (BLE), play significant roles in modern healthcare. However, most of the RF spectrum is licensed and regulated, and the effect of RF on human health is of major concern. Moreover, the signal-to-noise-plus-interference ratio in high distance can be decreased to a considerable extent, possibly leading to the increase in bit-error rate. Optical camera communication (OCC), which uses a camera to receive data from a light-emitting diode (LED), can be utilized in eHealth to mitigate the limitations of RF. However, OCC also has several limitations, such as high signal-blockage probability. Therefore, in this study, a hybrid OCC/BLE system is proposed to ensure efficient, remote, and real-time transmission of a patient’s electrocardiogram (ECG) signal to a monitor. First, a patch circuit integrating an LED array and BLE transmitter chip is proposed. The patch collects the ECG data according to the health condition of the patient to minimize power consumption. Second, a network selection algorithm is developed for a new network access request generated in the patch circuit. Third, fuzzy logic is employed to select an appropriate camera for data reception. Fourth, a handover mechanism is suggested to ensure efficient network allocation considering the patient’s mobility. Finally, simulations are conducted to demonstrate the performance and reliability of the proposed system.

scholarly journals Illuminance and Starting Distance of the Far Field of LED-Array Luminaire Operated at Short Working Distance

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 360
Author(s):  
Ching-Cherng Sun ◽  
Yi-Syuan Lin ◽  
Tsung-Hsun Yang ◽  
Shih-Kang Lin ◽  
Xuan-Hao Lee ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Light Sources ◽  
Far Field ◽  
Extended Source ◽  
Light Emitting ◽  
High Uniformity ◽  
Led Array ◽  
Working Distance ◽  
Divergent Angle ◽  
Short Working

A luminaire with a light-emitting diode (LED) array can provide hotspot illumination in a short range. Therefore, a design of a luminaire with the largest central illuminance (LCI) and a high uniformity is warranted. In this paper, we present a study of illuminance variation with respect to the distance of an illumination target of a luminaire with LED array. The emission property of the luminous intensity is characterized by the cosine power law or the divergent angle of full width at half maximum (FWHM). A real LED module is designed to create the simulation for different luminaire types. The occurrence of the LCI and the far-field region are observed. Our results demonstrate that the LCI distance remains shorter than the starting distance of the far field (SDFF). To simplify the simulation, we propose the replacement of the real LED module with a point or flat-extended source. Such light sources must be equipped with the specific cosine power factor corresponding to the divergent angle of the FWHM of the LED module. These light sources are acceptable for describing illumination characteristics, including the SDFF. Our results may facilitate the design of LED-array luminaires operated at short working distances, such as reading lighting or illumination in microscopes.

Photocrystallography – design and methodology for the use of a light-emitting diode device

2010 ◽  
Vol 43 (2) ◽  
pp. 337-340 ◽  
Author(s):  
Simon K. Brayshaw ◽  
Jason W. Knight ◽  
Paul R. Raithby ◽  
Teresa L. Savarese ◽  
Stefanie Schiffers ◽  
...  
Keyword(s):  
Single Crystal ◽  
Light Source ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Experimental Methodology ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
X Ray ◽  
Led Array

With the increase in interest in photocrystallographic experiments, the use of light-emitting diodes (LEDs) provides an alternative, low-budget light source (by comparison to lasers) and allows photocrystallographic experiments to be carried out readily. Here the design of an LED array device suitable for use in single-crystal X-ray diffraction experiments is reported, and the experimental methodology used for determining the structures of metastable species is described.

Thermal Investigation and Placement Design of High-Brightness LED Array Package on PCB for Uniform Illuminance

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
K. C. Yung ◽  
H. Liem ◽  
H. S. Choy ◽  
W. K. Lun
Keyword(s):  
Surface Temperature ◽  
Printed Circuit Board ◽  
Cfd Simulation ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Heat Transfer Analysis ◽  
Significant Drop ◽  
High Brightness ◽  
Light Emitting ◽  
Led Array

This paper reports the thermal performance of a high-brightness light-emitting diode (LED) array package with a novel placement method on a printed circuit board (PCB). The precise heat transfer analysis and modeling using computational fluid dynamics (CFD) were performed according to the practical working conditions of the LED array. Emphasis was placed upon investigating how the temperature of the surface of LEDs changed in accordance with different placement methods. A significant drop in the surface temperature of the LEDs was found when the triangular and arithmetic spacing placement methods were used; hence, the overall heat dissipating capability of the LED array to the PCB was improved. By optimizing the placement design, the average surface temperature of the LED array achieved a decrease of about 20%, from 120°C to 100°C. The illuminance level of each placement design was measured and compared. Both CFD simulation and experimental results are provided to demonstrate the efficacy of the proposed approach for LED array thermal management.

scholarly journals InGaN/GaN nanoLED Arrays as a Novel Illumination Source for Biomedical Imaging and Sensing Applications

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 892 ◽  
Author(s):  
Jan Gülink ◽  
Steffen Bornemann ◽  
Hendrik Spende ◽  
Matthias Auf der Maur ◽  
Aldo Di Carlo ◽  
...  
Keyword(s):  
Biomedical Imaging ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Sensing Applications ◽  
Device Processing ◽  
Led Array ◽  
Line Contacts ◽  
Processing Optimization ◽  
Illumination Source

Guidelines for the fabrication of nanoscale light-emitting diode arrays (i.e., nanoLED arrays) based on patterned gallium nitride (GaN) with very small dimensions and pitches have been derived in this work. Several challenges during top-down LED array processing have been tackled involving hybrid etching and polymer-based planarization to yield completely insulated highaspect-ratio LED fin structures and support the creation of p-GaN crossing line contacts, respectively. Furthermore, simulations of the light emission patterns were also performed providing hints for enhancing the device designs. As a result, regardless of the required device processing optimization, the developed nanoLED arrays are expected to offer high potential as novel illumination sources in biomedical imaging and sensing applications (e.g., mini compact microscopes and wearable biological/chemical nanoparticle counters)

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