Browsing by Author "Chiang, Chang-Lin"

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Dimmable sunlight-like organic light emitting diodes with ultra-high color rendering index
(2016-05)
Wu, Jin-Han
;
Chi, Chien-An
;
Chiang, Chang-Lin
;
Chen, Guan-Yu
;
Lin, Yi-Ping
We propose novel dimmable sunlight-like white organic light-emitting diodes that were fabricated using three luminophores to form an emitting spectrum similar to black body radiation at 2250 K with ultra-high color rendering index (CRI) value of 91, which nearly remained the constant at various luminance values ranging from 100 to more than 2500 cd/m(2) at Commission Internationale de l\'Eclairage chromaticity coordinates of (0.51, 0.41). Introducing charge modification layers suppressed the energy transfer between the emitting material layers and increased the probability of carrier recombination. Moreover, we reveal that covering long-wavelength ranges played a vital role in achieving high CRI values; the CRI values of a spectrum artificially shifted toward a long-wavelength direction (from 610 to 620 nm) remained constant, whereas those of a spectrum shifted toward a short-wavelength direction (from 610 to 600 nm) dropped to 79. (C) 2016 Elsevier B.V. All rights reserved.
Discharge and photo-luminance properties of a parallel plates electron emission lighting device
(2011-01-03)
Li, Chia-Hung
;
Liu, Ming-Chung
;
Chiang, Chang-Lin
;
Li, Jung-Yu
;
Chen, Shih-Pu
The gas discharge and photo-luminance properties of a planar lighting source featuring highly uniform light emission and mercury-free design were studied. The current density-voltage characteristics and the associated gas discharge of the devices operating with the values of the ratio of electric field to gas pressure (E/p) between 4.3 kV/Torr-cm and 35.7 kV/Torr-cm indicate that the width of the cathode fall extends over the entire gap between the two electrodes and the device is mostly in the obstructed discharge regime. The optical emission analysis confirmed the electron collision-induced gas emissions and strong effect of gas pressure on the phosphor emission when operated at constant current density, both are indicative of the primary roles played by the electron energy. (C)2011 Optical Society of America
Secondary electron emission characteristics of oxide electrodes in flat electron emission lamp
(2016-01-01)
Chiang, Chang-Lin
;
Zeng, Hui-Kai
;
Li, Chia-Hung
;
Li, Jung-Yu
;
Chen, Shih-Pu
The present study concerns with the secondary electron emission coefficient,., of the cathode materials used in the newly developed flat electron emission lamp (FEEL) devices, which essentially integrates the concept of using cathode for fluorescent lamp and anode for cathode ray tube (CRT) to obtain uniform planar lighting. Three different cathode materials, namely fluorine-doped tin oxide (FTO), aluminum oxide coated FTO (Al2O3/FTO) and magnesium oxide coated FTO (MgO/FTO) were prepared to investigate how the variations of. and working gases influence the performance of FEEL devices, especially in lowering the breakdown voltage and pressure of the working gases. The results indicate that the MgO/FTO bilayer cathode exhibited a relatively larger effective secondary electron emission coefficient, resulting in significant reduction of breakdown voltage to about 3kV and allowing the device to be operated at the lower pressure to generate the higher lighting efficiency. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).