Spectral Optimization of a Mixed White Light-Emitting Diode (LED) Cluster Comprising a Red/Green/Blue/Cyan/Yellow/Warm White LED

We prepared the surface mounted white light emitting diode (LED) chips by using yellow phosphors on the blue LED chip. The optical and electrical properties of prepared white LED chips were investigated. The yellow phosphor mixed with transparent epoxy was coated on the prepared LED chip. The optimum mixing conditions with epoxy and yellow phosphor is obtained at the mixing ration of epoxy: yellow phosphor = 97 : 3 wt %. The maximum luminance and light emitting efficiency are above 80,000 cd/m2 and 23.2 lm/W, respectively, at the bias voltage of 2.9 V. There was no distinct change in the luminance strength with changing of the yellow phosphor ratios. The flowing current of the white LED chip is about 30 mA at 2.9 V.

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Effects of Different Package Structures on Thermal Properties of High Power White LED

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.503.397 ◽

2012 ◽

Vol 503 ◽

pp. 397-401 ◽

Cited By ~ 1

Author(s):

Zhe Ran Sun ◽

Da Ming Wu ◽

Ya Jun Zhang ◽

Jian Zhuang ◽

Kai Fang Dang

Keyword(s):

Thermal Properties ◽

Thermal Resistance ◽

White Light ◽

High Power ◽

Light Emitting Diode ◽

White Led ◽

Forward Voltage ◽

Light Emitting

The characteristics of several package structures of high power white Light emitting diode (LED) are described in this paper. The influence of different structures on thermal properties is analyzed. Forward voltage method is used to test the thermal resistance of LED chips.

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Synthesis of Rare Earth Doped with Tungstate and Phosphate Luminescent Materials and Its Adoption in Light-Emitting Diode

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2020.2784 ◽

2020 ◽

Vol 15 (5) ◽

pp. 654-662

Author(s):

Xueai Yin ◽

Weiwei Feng ◽

Xin Zhang

Keyword(s):

White Light ◽

Light Emitting Diode ◽

Powder Materials ◽

Luminescent Materials ◽

White Led ◽

Light Emitting ◽

Single Matrix ◽

Color Rendering ◽

Rare Earth Doped ◽

Uv Excitation

This research focuses on the fluorescent powder materials based on a single matrix of this type of LED. Taking Ba2CaWO6 as an example, mixing Dy3+ alone can produce blue and white light at 318nm UV excitation. At the same time, mixing Dy3+ with Eu3+ can make the fluorescent powders realize the emission of 491 nm/577 nm of Dy3+ and 588 nm of Eu3+. Dy3+ is set to 0.06 and the ratio of Eu3+ is adjusted to make the luminous color gradually close to white. In the study of Ba3Y(PO4)3 · xDy3+ · yEu3+, x is set as 0.07, and the content of y is set as 0.01∼0.08. Dy3+ alone will emit blue and white light under the laser at 391 nm. By increasing the content of Eu3+, polychromatic emission can be carried out, and white light can be obtained by adjusting the concentration of Eu3+. At the same time, the application functions of white LED packaging are tested for the above materials. The results show that both Ba2CaWO6 · xDy3+ · yEu3+ and Ba3Y(PO4)3 · xDy3+ · yEu3+ materials can realize white lighting by adjusting the ratio of Eu3+ · Dy3+, increasing the proportion of Eu3+ can improve the color rendering of white LED.

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Modern Aspects on Strategies for Developing Single-Phase Broadly Tunable White Light-Emitting Phosphors

Journal of Materials Chemistry C ◽

10.1039/d1tc02952e ◽

2021 ◽

Author(s):

Sayed Ali Khan ◽

Noor Zamin Khan ◽

Muhammad Sohail ◽

Jahangeer Ahmed ◽

Norah Alhokbany ◽

...

Keyword(s):

White Light ◽

Single Phase ◽

Light Emitting Diode ◽

White Led ◽

Light Emitting

In phosphors intended for the applications of white light-emitting diode (white-LED), their ability to achieve controlled-photoluminescence-tuning is an important feature, directly linked to their optimization and modification. More specifically, the...

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New Y2LuCaAl2SiO12:Ln (Ln = Ce3+, Eu3+, and Tb3+) phosphors for white LED applications

Inorganic Chemistry Frontiers ◽

10.1039/c8qi00111a ◽

2018 ◽

Vol 5 (6) ◽

pp. 1336-1345 ◽

Cited By ~ 29

Author(s):

D. A. Hakeem ◽

J. W. Pi ◽

S. W. Kim ◽

K. Park

Keyword(s):

Solid State ◽

White Light ◽

Light Emitting Diode ◽

Solid State Lighting ◽

White Led ◽

Garnet Structure ◽

Light Emitting

New garnet structure Y2−xLuCaGaAl2SiO12:xLn (Ln = Ce3+, Eu3+, and Tb3+) phosphors were explored for white light-emitting diode and solid-state lighting applications.

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High speed transmission of signal level for white light emitting diode (LED) as a transmitter device by using modified phase equalization

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v17.i3.pp1348-1354 ◽

2020 ◽

Vol 17 (3) ◽

pp. 1348

Author(s):

Maad Mohsin Mijwil

Keyword(s):

White Light ◽

Communication System ◽

High Speed ◽

Finite Impulse Response ◽

Light Emitting Diode ◽

Visible Light Communication ◽

White Led ◽

Light Emitting ◽

System Data ◽

Two Phases

Visible light communication (VLC) also known as "Li-Fi", uses standard LEDs to transmit data such as information, images, music, and videos. The first LED was developed in 1927 by Oleg Vladimírovich Lósev (1903-1942), however it was not used in the industry until the 1960s.In this paper, will describe the implementation of Modified Phase Equalization (MPH) on visible white LED lamps signal because it's has slow transition time that severely limits in the communication system data speeds with phase equalization that increases the bandwidth of the LED modulation. Employ two filters with Modified Phase Equalization: first, Complementary (C) filter to combine between all kinds moving signals and second, finite impulse response (FIR) filter to obtain all coefficients that respective. Implementation in two phases: first, frequency 150KHz with number of signals 15000 signals and second, doubling frequency 300KHz with number of signals 30000 signals of LEDs without losing their main functionality as illumination sources.

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Spectral optimization of warm-white light-emitting diode lamp with both color rendering index (CRI) and special CRI of R9 above 90

AIP Advances ◽

10.1063/1.3644342 ◽

2011 ◽

Vol 1 (3) ◽

pp. 032160 ◽

Cited By ~ 15

Author(s):

Guoxing He ◽

Jing Xu ◽

Huafeng Yan

Keyword(s):

White Light ◽

Light Emitting Diode ◽

Light Emitting ◽

Warm White Light ◽

Color Rendering Index ◽

Spectral Optimization ◽

Color Rendering

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Design of a Bicycle Head Lamp Using an Atypical White Light-Emitting Diode with Separate Dies

Crystals ◽

10.3390/cryst9120659 ◽

2019 ◽

Vol 9 (12) ◽

pp. 659 ◽

Cited By ~ 1

Author(s):

Hsin-Jung Lin ◽

Ching-Cherng Sun ◽

Chi-Shou Wu ◽

Xuan-Hao Lee ◽

Tsung-Hsun Yang ◽

...

Keyword(s):

White Light ◽

Optical Model ◽

Light Emitting Diode ◽

Weighting Factor ◽

White Led ◽

High Contrast ◽

Coverage Area ◽

Light Emitting ◽

Light Pattern

To the best of our knowledge, this is the first demonstration of a design for a bicycle head lamp with a high-contrast cutoff line using an atypical white light-emitting diode (LED) with two separate dies. The precise optical model was created by setting the weighting factor on the emitting surface. The downward reflector was designed and fabricated to produce a high-contrast cutoff line in both short- and long-axis orientations, but a yellowish outer pattern was observed. A modified two-color optical model was created to describe the yellowish patterns in both orientations and explain the yellowish effect. Such an effect was caused by the larger coverage area of the phosphor than that by the blue dies. To reduce the yellowish effect near the cutoff line, a specific phosphor area was blocked in the experiment. The yellowish effect was greatly reduced, and the contrast across the cutoff line was enhanced. The presented technology is useful for designing a high-contrast light pattern with such an atypical white LED.

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