High Power 325 Light Emitting Diode Arrays by Flip-Chip Packaging

2002 ◽  
Vol 743 ◽  
Author(s):  
Ashay Chitnis ◽  
Maxim Shatalov ◽  
Vinod Adivarahan ◽  
Jian Ping Zhang ◽  
Shuai Wu ◽  
...  
Keyword(s):  
Thermal Management ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Flip Chip Packaging ◽  
Ultraviolet Light Emitting Diodes ◽  
Emission Light

ABSTRACTWe report flip-chip 325 nm emission light emitting diodes over sapphire with dc powers as high as 0.84 mW at 180mA and pulse powers as high as 6.68 mW at 1A. These values to date are the highest reported powers for such short wavelength emitters. Our data shows the device output power under dc operation to be limited by the package heat dissipation. A study is presented to determine the role of thermal management in controlling the power output for the reported 325 nm ultraviolet light emitting diodes.

scholarly journals Thermal Performance of LED Filament in Flip-Chip Packaging Manufactured for Different Correlated Color Temperature

2021 ◽  
Vol 11 (19) ◽  
pp. 8844
Author(s):  
He Jiang ◽  
Jiming Sa ◽  
Cong Fan ◽  
Yiwen Zhou ◽  
Hanwen Gu ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Color Difference ◽  
Junction Temperature ◽  
Color Temperature ◽  
Constant Current ◽  
Light Emitting ◽  
Flip Chip Packaging

The effect of correlated color temperature (CCT) on the thermal performance of light emitting diode (LED) filament in flip-chip packaging was investigated in detail. Two filaments with different lengths were selected as the research object, and the thermal resistance of filaments under three CCT (2200 K, 2400 K, 2700 K) were studied. The optical properties and thermal parameters of the two groups of filaments were measured, and the results were analyzed combined with the color coordinate. The experimental results show that thermal properties of LED filaments is closely related to CCT. Under constant current condition, junction temperature decreases with the increase of color difference. With the change of phosphor glue and phosphorus powder ratio, the color temperature of LED filament also changes. In the filaments with the same chip structure and packaging mechanism, the higher the proportion of red phosphorescent powder, the worse the heat dissipation performance of the filament. These results show that in the design and manufacture of LED filament, it is helpful to control the CCT of LED filament under the premise of meeting the use requirements.

scholarly journals Graphene-Based Transparent Conducting Substrates for GaN/AlGaN Nanocolumn Flip-Chip Ultraviolet Light-Emitting Diodes

2021 ◽  
Author(s):  
Andreas Liudi Mulyo ◽  
Anjan Mukherjee ◽  
Ida Marie Høiaas ◽  
Lyubomir Ahtapodov ◽  
Tron Arne Nilsen ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Flip Chip ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Transparent Conducting ◽  
Ultraviolet Light Emitting Diodes

scholarly journals High-Power GaN-Based Vertical Light-Emitting Diodes on 4-Inch Silicon Substrate

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1178 ◽  
Author(s):  
Qiang Zhao ◽  
Jiahao Miao ◽  
Shengjun Zhou ◽  
Chengqun Gui ◽  
Bin Tang ◽  
...  
Keyword(s):  
High Power ◽  
Silicon Substrate ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Current Spreading ◽  
Light Emitting ◽  
Fabry Perot ◽  
Lift Off

We demonstrate high-power GaN-based vertical light-emitting diodes (LEDs) (VLEDs) on a 4-inch silicon substrate and flip-chip LEDs on a sapphire substrate. The GaN-based VLEDs were transferred onto the silicon substrate by using the Au–In eutectic bonding technique in combination with the laser lift-off (LLO) process. The silicon substrate with high thermal conductivity can provide a satisfactory path for heat dissipation of VLEDs. The nitrogen polar n-GaN surface was textured by KOH solution, which not only improved light extract efficiency (LEE) but also broke down Fabry–Pérot interference in VLEDs. As a result, a near Lambertian emission pattern was obtained in a VLED. To improve current spreading, the ring-shaped n-electrode was uniformly distributed over the entire VLED. Our combined numerical and experimental results revealed that the VLED exhibited superior heat dissipation and current spreading performance over a flip-chip LED (FCLED). As a result, under 350 mA injection current, the forward voltage of the VLED was 0.36 V lower than that of the FCLED, while the light output power (LOP) of the VLED was 3.7% higher than that of the FCLED. The LOP of the FCLED saturated at 1280 mA, but the light output saturation did not appear in the VLED.

Fabrication of High‐Voltage Flip Chip Deep Ultraviolet Light‐Emitting Diodes Using an Inclined Sidewalls Structure

2019 ◽  
Vol 216 (16) ◽  
pp. 1900059
Author(s):  
Zhibai Zhong ◽  
Xuanli Zheng ◽  
Jinchai Li ◽  
Jinjian Zheng ◽  
Yashu Zang ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
High Voltage ◽  
Flip Chip ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Deep Ultraviolet ◽  
Ultraviolet Light Emitting Diodes

Effective Thermal Management in Ultraviolet Light-Emitting Diodes With Micro-LED Arrays

2013 ◽  
Vol 60 (2) ◽  
pp. 782-786 ◽  
Author(s):  
N. Lobo Ploch ◽  
H. Rodriguez ◽  
C. Stolmacker ◽  
M. Hoppe ◽  
M. Lapeyrade ◽  
...  
Keyword(s):  
Thermal Management ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Ultraviolet Light Emitting Diodes ◽  
Led Arrays

scholarly journals Optical and Thermal Analysis of Secondary Optics in Light Emitting Diodes’ Packaging: Analysis of MR16 Lamp

2021 ◽  
Vol 2116 (1) ◽  
pp. 012121
Author(s):  
Mohammad Azarifar ◽  
Ceren Cengiz ◽  
Mehmet Arik
Keyword(s):  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Thermal Characterization ◽  
Thermal Control ◽  
Light Extraction Efficiency ◽  
Thickness Effect ◽  
Package Design ◽  
Light Emitting

Abstract Optical and thermal control are two main factors in package design process of lighting products, specifically light emitting diodes (LEDs). This research is aimed to study the role of secondary optics in opto-thermal characterization of LED packages. Novel thin total internal reflection (TIR) multifaceted reflector (MR) lens is modelled and optimized in Monte-Carlo ray-tracing simulations for MR16 package, regarded as one of the widely used LED lighting products. With criteria of designing an optical lens with 50% reduced thickness in comparison to commercially available lenses utilized in MR16 packages, nearly same light extraction efficiency and more uniform beam angles are achieved. Optical performance of the new lens is compared with the experimental results of the MR16 lamp with conventional lens. Only 2.3% reduction in maximum light intensity is obtained while lens size reduction was more than 25%. Based on the detailed CAD design, heat transfer simulations are performed comparing the lens thickness effect on heat dissipation of MR16 lamp. It was observed that using thinner lenses can reduce the lens and chip temperature, which can result in improved light quality and lifetime of both lens and light source.

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