Design of the Ring Remote Phosphor Structure for Phosphor-Converted White-Light-Emitting Diodes

Lin, Ming Te; Ying, Shang Ping; Tai, Kuang Yu; Tai, Sheng Chieh; Liu, Chih Hsuan; Chen, Jyh Chen; Sun, Ching Cherng

doi:10.1143/jjap.49.072101

Cited by 29 publications

(15 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ordinary two-step molding process was used to fabricate the ring-remote-phosphor layer around the central encapsulant [14], [15]. The inverted-cone-lens surface of the encapsulant was formed using a cylindrical cavity mold with a conical prominence at the bottom following the LED chip mounted on heat sink and wiring.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Inverted-Cone-Lens Encapsulant With Gradient Surface for Ring-Remote-Phosphor Structure

Lin¹,

Ying²,

Lin³

et al. 2014

IEEE Trans. Device Mater. Relib.

Self Cite

View full text Add to dashboard Cite

The ordinary ring-remote-phosphor structure consisting of an inverted-cone-lens encapsulant and a surrounding ring-remote-phosphor layer reduces the probability of the backward light from the phosphor layer to the absorptive lightemitting diode (LED) chip and then increases the package extraction efficiency. However, some of the blue light emitting from the LED chip impinges on the inverted-cone-lens surface and then escapes without hitting the ring-remote-phosphor layer. The blue light leakage from the inverted-cone-lens surface is a serious problem for the ring-remote-phosphor structure devices in use, because it will lower the actual illumination effects and result in discomfort for the eyes. In this paper, we discuss the predominant factors of the blue light leakage from the inverted-cone-lens surface and propose an improve ring-remote-phosphor structure that utilizes an inverted-cone-lens encapsulant with gradient surface to decrease the blue light leakage. Ray-tracing simulations are performed to analyze the blue light leakages from the ordinary and improved inverted-cone-lens encapsulants in the ring-remotephosphor structures. The simulation results show that the improved inverted-cone-lens encapsulants get almost no blue light leakage from the inverted-cone-lens surface directly and then lessen the discomfort for the eyes. Our results further demonstrate that the improved ring-remote-phosphor structure device will have higher angular color uniformity than the ordinary one.Index Terms-Blue light leakage, inverted-cone-lens encapsulant with gradient surface, phosphor-converted white lightemitting diodes (LEDs), ring-remote-phosphor structure.

show abstract

Section: Resultsmentioning

confidence: 99%

“…In 2009, our research group demonstrated the ringremote-phosphor structure for pcLEDs [14], [15]. The ringremote-phosphor structure consists of an inverted-cone-lens encapsulant and a surrounding ring-remote-phosphor layer.…”

Section: Inverted-cone-lens Encapsulant With Gradientmentioning

confidence: 99%

Inverted-Cone-Lens Encapsulant With Gradient Surface for Ring-Remote-Phosphor Structure

Lin¹,

Ying²,

Lin³

et al. 2014

IEEE Trans. Device Mater. Relib.

Self Cite

View full text Add to dashboard Cite

show abstract

“…For encapsulants with intermediate refractive indices, θ c increases and ultimately LEE increases. There have been many studies of encapsulants addressing modification of the shape of the encapsulation [14], addition of particles into the encapsulant [15], the effects of the hardening characteristics of the encapsulant [16], the development of encapsulants with high refractive indices [17,18], and multilayered encapsulation [19]. Most of these studies have focused on spherical encapsulants, but because of the current trend of using high-power, multichip LED packages, the need to study flat encapsulants has arisen.…”

Section: )mentioning

confidence: 99%

Improvement of Light Extraction Efficiency of LED Packages Using an Enhanced Encapsulant Design

Choi

Park

Moon

2014

Journal of the Optical Society of Korea

View full text Add to dashboard Cite

We optimized the design of the flat encapsulant of a light-emitting diode (LED) package to obtain higher light output power (LOP), both by experiment and simulation using three-dimensional ray-tracing software. In the experiment, the refractive index of the encapsulant was varied (1.41 and 1.53). In addition, double-layer structures with these refractive indices (1.41/1.53) were investigated by varying the shape of the interface between the two among flat, concave, and convex. The experiments showed that the LOP of the double-layer encapsulant with convex interface increased by 13.4% compared to the single-layer encapsulant with a refractive index 1.41, which was explained by the increase of the light extraction efficiency (LEE) in connection with the increase of the critical angle (θ c ) and the decrease of the Fresnel reflection.

show abstract

“…To improve the extraction efficiency of the remote phosphor structure with low angular-dependent correlated color temperature (CCT) deviation, the phosphor structures with a textured surface or dual-layer phosphor, obtained using the pulse spray coating method, were used to increase the package efficiency and color uniformity [5]. The ring remote phosphor structure proposed by Lin et al consists of an inverted cone lens encapsulant; a surrounding ring remote phosphor layer was later developed [6][7][8]. The ring remote phosphor layer could increase the extraction of back-transferred light and enhance the luminous efficacy to a greater extent.…”

Section: Introductionmentioning

confidence: 99%

Investigation of remote-phosphor white light-emitting diodes with improved scattered photon extraction structure

Ying

Shiu

2015

Appl. Opt.

Self Cite

View full text Add to dashboard Cite

In this study, an improved scattered photon extraction (SPE) package structure with a reflection plate over the remote phosphor layer is presented. The important factors for the remote phosphor layer in the conventional and improved SPE package structures, including the phosphor layer thickness and phosphor concentration, are also studied. The simulation results show that the yellow-blue ratio (YBR) of the conventional and improved SPE package structure increases with the phosphor concentration when the phosphor layer is thin and that the YBR is saturated when the layer is thick. The experimental results show that for both conventional and improved SPE package structure, the correlated color temperature (CCT) decreases as the phosphor concentration increases. However, the YBR of the improved SPE package structure is higher than that of the conventional SPE package structure for a given phosphor layer thickness and phosphor concentration. That is, in the conventional SPE package structure, it is necessary to increase the phosphor concentration and then increase the absorption of blue light to obtain more yellow light. Hence, for the improved SPE package structure, less phosphor is required in the phosphor layer for achieving the chosen CCT.

show abstract

Design of the Ring Remote Phosphor Structure for Phosphor-Converted White-Light-Emitting Diodes

Cited by 29 publications

References 10 publications

Inverted-Cone-Lens Encapsulant With Gradient Surface for Ring-Remote-Phosphor Structure

Inverted-Cone-Lens Encapsulant With Gradient Surface for Ring-Remote-Phosphor Structure

Improvement of Light Extraction Efficiency of LED Packages Using an Enhanced Encapsulant Design

Investigation of remote-phosphor white light-emitting diodes with improved scattered photon extraction structure

Contact Info

Product

Resources

About