Improvement of light quality by DBR structure in white LED

Lin, Huang; Chen, Kuo Ju; Wang, Sheng Wen; Lin, Chien Chung; Wang, Kuan Yu; Li, Jie Ru; Lee, Po Tsung; Shih, Min‐Hsiung; Li, Xiuling; Chen, Huang Ming; Kuo, Hao Chung

doi:10.1364/oe.23.000a27

Cited by 38 publications

(10 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S5c,d ). A DBR structure is suggested to be used to enhance the quality of light emission at different driving currents 24 . Also we found that the color shift at different viewing angles.…”

Section: Resultsmentioning

confidence: 99%

Pulsed-laser micropatterned quantum-dot array for white light source

Wang

Lin

et al. 2016

Sci Rep

Self Cite

View full text Add to dashboard Cite

In this study, a novel photoluminescent quantum dots device with laser-processed microscale patterns has been demonstrated to be used as a white light emitting source. The pulsed laser ablation technique was employed to directly fabricate microscale square holes with nano-ripple structures onto the sapphire substrate of a flip-chip blue light-emitting diode, confining sprayed quantum dots into well-defined areas and eliminating the coffee ring effect. The electroluminescence characterizations showed that the white light emission from the developed photoluminescent quantum-dot light-emitting diode exhibits stable emission at different driving currents. With a flexibility of controlling the quantum dots proportions in the patterned square holes, our developed white-light emitting source not only can be employed in the display applications with color triangle enlarged by 47% compared with the NTSC standard, but also provide the great potential in future lighting industry with the correlated color temperature continuously changed in a wide range.

show abstract

Section: Resultsmentioning

confidence: 99%

Pulsed-laser micropatterned quantum-dot array for white light source

Wang

Lin

et al. 2016

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Different processes can be used to deposit DBR layers, such as chemical vapor deposition [8,9], sol-gel [10,11], sputtering [5,7] and electron-beam evaporation [12][13][14]. Due to their high reflectivity and low losses, DBRs have been widely used in many areas like optical filters [15], micro-cavities [7,16], vertical-cavity surface-emitting lasers [17], photonic crystals [18], organic light emitting diodes [19] and enhancement of emitting efficiency [20,21]. However, a current limitation of the DBR is that only the high reflection under a near-normal incidence is considered, also in a limited wavelength interval.…”

Section: Introductionmentioning

confidence: 99%

Design, fabrication and characterization of a distributed Bragg reflector for reducing the étendue of a wavelength converting system

et al. 2020

View full text Add to dashboard Cite

In this work, the design, fabrication and characterization are reported for a distributed Bragg reflector (DBR) filter with a specific wavelength and angular dependency, which aims to improve the light collection from a wavelength-converter-based light source into a smaller angle than the full angle Lambertian emission. The desired design is obtained by optimizing the transmission characteristics of a multi-layer structure. Titania (TiO 2 ) and silica (SiO 2 ) are used as high and low refractive index materials, respectively. The deposition is made by electron beam evaporation without substrate heating, followed by a post-annealing procedure. The optical properties of the evaporated layers are analyzed by ellipsometer and spectrometer measurements. The angular and wavelength dependency of the fabricated DBR is in good agreement with simulations for the designed structure.

show abstract

“…This has become the most common approach for white light generation [9]. To achieve different color gamut, color rendering index (CRI), light quality, and efficiency specifications for various applications, many novel phosphors that increase the efficiency or color performance of LEDs have been developed [10][11][12][13]. Among the several phosphors for LED applications, yttrium aluminum garnet (YAG)-, silicate-, and nitride-based phosphors are used most widely in WLEDs because of their well developed fabrication processes and outstanding features.…”

Section: Introductionmentioning

confidence: 99%

Novel Method for Estimating Phosphor Conversion Efficiency of Light-Emitting Diodes

et al. 2018

Self Cite

View full text Add to dashboard Cite

This study presents a novel method for estimating the phosphor conversion efficiency of white light-emitting diodes (WLEDs) with different ratios of phosphors. Numerous attempts have been made for predicting the phosphor conversion efficiency of WLEDs using Monte Carlo ray tracing and the Mie scattering theory. However, because efficiency depends on the phosphor concentration, obtaining a tight match between this model and the experimental results remains a major challenge. An accurate prediction depends on various parameters, including particle size, morphology, and packaging process criteria. Therefore, we developed an efficient model that can successfully correlate the total absorption ratio to the phosphor concentration using a simple equation for estimating the spectra and lumen output. The novel and efficient method proposed here can accelerate WLED development by reducing costs and saving fabrication time.

show abstract

Improvement of light quality by DBR structure in white LED

Cited by 38 publications

References 25 publications

Pulsed-laser micropatterned quantum-dot array for white light source

Pulsed-laser micropatterned quantum-dot array for white light source

Design, fabrication and characterization of a distributed Bragg reflector for reducing the étendue of a wavelength converting system

Novel Method for Estimating Phosphor Conversion Efficiency of Light-Emitting Diodes

Contact Info

Product

Resources

About