Exposure study on UV-induced degradation of PTFE and ceramic optical diffusers

Tsai, Benjamin K.; Cooksey, Catherine C.; Allen, David W.; White, Christopher C.; Byrd, Eric; Jacobs, Deborah S.

doi:10.1364/ao.58.001215

Cited by 18 publications

(13 citation statements)

References 14 publications

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“…With the scattered function that SiO2 nano-particles have, the light of blue and yellow can be evenly scattered. The CCT deviations will however be influenced by more SiO2 nano-particles than 10 mg cm 2 , but the quality is much higher than the conventional distant phosphorus configuration. The findings showed that the 10 mg cm 2 SiO2 nano-particles' distant phosphorous configuration was not only able to boost the homogeneity of CCT that dependent on the angle, but also to enhance the flux of lumination.…”

Section: Resultsmentioning

confidence: 95%

“…The demand to substitute incandescent lamps producing "warm" white color with a novel illumination supply with superior CRI and poor CCT has pushed phosphors outside the usual YAG: Ce. Mixing red emitted phosphors with yellow phosphors will enhance color intensity but capacity of the energy of LEDs will be remarkably reduced [2]. After that, among light output and white LED power efficiency there will be an exchange.…”

Section: Introductionmentioning

confidence: 99%

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Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

Thi

That

2021

Bulletin EEI

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SiO2 nano-particles have been examined in a distant phosphor structure for the elevated luminous quality and better consistency of white light-emitting diodes with angular-dependent associated color temperature (CCT). The luminous scattering ability could be increased by applying SiO2 nano-particles contain silicone to the outside of the phosphorus coating. In specific, the strength of blue light at wide angles is increased and differences in CCT can be minimized. In addition, owing to the sufficient refractive indices of silicone-containing SiO2 nanoparticles between the air and phosphorus layers, the luminous flux was improved. This new configuration decreases angular-dependent CCT deviations in the range of -700 to 700 from 1000 to 420 K. In comparison, at a 120 mA driving current, the rise of lumen flux increased by 2.25% relative to an usual distant phosphor structure without SiO2 nano-particles. As a result, in a distant phosphor structure, the SiO2 nano-particles could not only enhance the uniformity of illumination but also enhance the output of light.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

Thi

That

2021

Bulletin EEI

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“…Nevertheless, the angular correlated color temperature achieved from this method is in poor quality and the "yellow ring" phenomenon that is disadvantageous to the light performance of WLED also occurs [7][8][9]. Researchers proposed various methods as solutions to these problems, for example, conformal-phosphor structure [10], adjusting the surface phosphor layer [11], lens design [12], and optimizing the structure of a WLED package [13,14]. Though the enhancement in CCT homogeneity of these approaches was confirmed, their production confronts many difficulties, and they are also expensive to use in mass production.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the application of ZnO nanostructures to improve the optical performance of white light-emitting diodes

2021

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Though combining blue LED chips with yellow phosphor has been the most common method in white light-emitting diode (WLED) production, the attained angular correlated color temperature (CCT) uniformity is still poor. Thus, this article proposes to add ZnO nanostructures to WLED packages to promote the color uniformity of the WLEDs. The outcomes of the research demonstrate that utilizing ZnO at different amount can affect the scattering energy and the CCT deviations in WLEDs packages in different extents. Particularly, adding the node-like (N-ZnO), sheet-like (S-ZnO), and rod-like (R-ZnO) leads to the corresponding decreases of CCT deviations from 3455.49 K to 96.30 K, 40.03 K, and 60.09 K, respectively. Meanwhile, with 0.25% N-ZnO, 0.75% S-ZnO, and 0.25% R-ZnO, WLED devices can achieve both better CCT homogeneity and lower reduction in luminous flux. The results of this article can be a valuable document for the manufacturer to use as reference in improving their WLED products.

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“…The addition of QDs into pc-LEDs has been proven through experiments to be advantageous to CRI and chromatic performance, and even high light output with the emission wavelength of QDs [14]- [16]. QDs can be merged in pc-LEDs whether through coating a compound of phosphor-silicone gel and QDs onto the chip of the LED or apply remote structure and coat the QDs layer and phosphor layer distinctively [17]- [20]. In the method that blends the components together, QDs is placed into reflection cup and close to the LED chip.…”

Section: Introductionmentioning

confidence: 99%

Effects of NaB2O4:Mn2+ and Ba2Li2Si2O7:Sn3+,Mn2+ phosphors and remote structure organizations on the white light-emitting diodes with quantum dots and phosphors

Binh

2021

Bulletin EEI

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In order to increase the optical features of white light-emitting diodes (WLEDs), quantum dots (QDs) and phosphor materials have been proposed because of outstanding performance. The configuration of WLEDs with QDs layer and phosphor-silicone layer suggested placing these components separately to limit light loss, and enhance consistency at contact surface of QDs. In this research, the effects of QDs and phosphor on the performance of WLEDs are concluded through experiments. The emitted light and PL spectra were examined thoroughly, and infrared thermal imagers were applied to simulate the heat generation of an actual WLED device. The results show that with the configuration of 60 mA energy source, WLEDs which has the QDs-on-phosphor form attained luminous efficiency (LE) of 110 lm/W, with color rendering index (CRI) of Ra=92 and R9=80, whereas the WLEDs which has the phosphor-on-QDs form only has 68 lm/W in LE, Ra=57 and R9=24. Furthermore, WLEDs which has the QDs-on-phosphor form has less high temperature generated at the components’ conjunction in comparison to the counterpart, the peak generated heat in QDs-on-phosphor WLEDs is also lower and the heating capacity gap between 2 structures can go up to 12.3°C.

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Exposure study on UV-induced degradation of PTFE and ceramic optical diffusers

Cited by 18 publications

References 14 publications

Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

Investigation on the application of ZnO nanostructures to improve the optical performance of white light-emitting diodes

Effects of NaB<sub>2</sub>O<sub>4</sub>:Mn<sup>2+</sup> and Ba<sub>2</sub>Li<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:Sn<sup>3+</sup>,Mn<sup>2+</sup> phosphors and remote structure organizations on the white light-emitting diodes with quantum dots and phosphors

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