Active Packaging Method for Light-Emitting Diode Lamps With Photosensitive Epoxy Resins

Wang, Hao; Lee, Kyu-Seung; Ryu, Jae-Hyoung; Hong, Chang–Hee; Cho, Yong-Hoon

doi:10.1109/lpt.2007.910760

Cited by 18 publications

(13 citation statements)

References 7 publications

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“…Low temperature and non-thermal curing reduces the thermal effects on materials and thereby improves the initial performance of LEDs. Photosensitive silicones can even realize the fabrication of self-focused lens without molds [111,112], which could reduce charges for the latter.…”

Section: Prospectmentioning

confidence: 99%

Status and prospects for phosphor-based white LED packaging

Liu

Wang

et al. 2009

Front. Optoelectron. China

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The status and prospects for high-power, phosphor-based white light-emitting diode (LED) packaging have been presented. A system view for packaging design is proposed to address packaging issues. Four aspects of packaging are reviewed: optical control, thermal management, reliability and cost. Phosphor materials play the most important role in light extraction and color control. The conformal coating method improves the spatial color distribution (SCD) of LEDs. High refractive index (RI) encapsulants with high transmittance and modified surface morphology can enhance light extraction. Multi-phosphor-based packaging can realize the control of correlated color temperature (CCT) with high color rendering index (CRI). Effective thermal management can dissipate heat rapidly and reduce thermal stress caused by the mismatch of the coefficient of thermal expansion (CTE). Chip-on-board (CoB) technology with a multilayer ceramic substrate is the most promising method for high-power LED packaging. Low junction temperature will improve the reliability and provide longer life. Advanced processes, precise fabrication and careful operation are essential for high reliability LEDs. Cost is one of the biggest obstacles for the penetration of white LEDs into the market for general illumination products. Mass production in terms of CoB, system in packaging (SiP), 3D packaging and wafer level packaging (WLP) can reduce the cost significantly, especially when chip cost is lowered by using a large wafer size.

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Section: Prospectmentioning

confidence: 99%

Status and prospects for phosphor-based white LED packaging

Liu

Wang

et al. 2009

Front. Optoelectron. China

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“…Conventional optical polymers for encapsulants and lensing of LEDs are epoxy resins [5][6][7][8], polymethylmethacrylate (PMMA) [9,10], polycarbonate (PC) [9][10][11][12], acrylates [9], polystyrene (PS) [9] and cyclic olefin polymer and copolymer (COP/COC) [9]. Polyurethane (PU) materials are also candidates for the encapsulation of LEDs and organic LEDs (OLEDs) in particular due to their excellent properties for lens formation by evaporative polymer droplet deposition and imprint processes [13,14].…”

Section: Introductionmentioning

confidence: 99%

Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses

Bauer

Gutke

Heinrich

et al. 2020

Opt. Mater. Express

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In this work we present a novel optical polymer system based on polyurethane elastomer components, which combines excellent UV transparency with high thermal stability, good hardness, high surface tension and long pot life. The material looks very promising for encapsulation and microlensing applications for chip-on-board (CoB) light-emitting diodes (LED). The extinction coefficient k, refractive index n, and bandgap parameters were derived from transmission and reflection measurements in a wavelength range of 200-890 nm. Thermogravimetry and differential scanning calorimetry were used to provide glass transition and degradation temperatures. The surface tension was determined by means of contact angle measurements. As proof of concept, a commercial InGaN-CoB-LED is used to demonstrate the suitability of the new material for the production of microlenses.

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“…[1][2][3] Transparent epoxy resins are generally used as encapsulants in the blue LED assembly field. 4 However, there are two major disadvantages of using epoxy resins as LED encapsulants. One disadvantage is that cured epoxy resins are generally hard and brittle because of rigid cross-linked networks.…”

Section: Introductionmentioning

confidence: 99%

Study of thermal and optical properties of epoxy/organically modified silicate hybrids

Wu¹,

Cheng²,

Wang³

et al. 2016

Mat Express

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Three epoxy resins were examined in this study: Eporite-901 (474 g/eq), Eporite-904 (807 g/eq) and Eporite-909 (1915 g/eq), which are bisphenol-A-type epoxy resins. In this study, we used an amine terminated organically modified silicate (Ormosil) that was compatible with the diglycidyl ether of bisphenol-A epoxy to partially replace the epoxy resin at various ratios, cured by hexahydrophthalic anhydride (HHPA). The thermal and optical properties of the Ormosil-modified epoxy resins (Epoxy/Ormosil) were studied. The M n and M w of the resulting hybrids were in the range of 10668-31450 and 30617-120422, respectively, with a polydispersity index range of 2.870-3.829. The thermogravimetric analysis (TGA) results implied that Ormosil can raise the crosslink density and enhance the thermal properties. The optical properties were measured after curing and thermal aging of the polymer films with thickness around 8-10 mm. The refractive indexes of the Epoxy/Ormosil hybrids were 1.62-1.68, and the transmittances of the cured composites were above 85% in the visible wavelength.The key attributes of Epoxy/Ormosil hybrids that make them attractive materials for LEDs including their high transparency in the UV-visible region, controlled refractive index (RI), and excellent thermal resistance.

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Active Packaging Method for Light-Emitting Diode Lamps With Photosensitive Epoxy Resins

Cited by 18 publications

References 7 publications

Status and prospects for phosphor-based white LED packaging

Status and prospects for phosphor-based white LED packaging

Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses

Study of thermal and optical properties of epoxy/organically modified silicate hybrids

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