A novel candle light-style OLED with a record low colour temperature

2019 ◽  
Vol 55 (89) ◽  
pp. 13354-13357 ◽  
Author(s):  
Vladislav M. Korshunov ◽  
Timofey N. Chmovzh ◽  
Ekaterina A. Knyazeva ◽  
Ilya V. Taydakov ◽  
Ludmila V. Mikhalchenko ◽  
...  
Keyword(s):  
Color Temperature ◽  
Colour Temperature ◽  
Candle Light

Candle light-style OLEDs based on new D–A–π–A type molecules incorporated into Alq3 matrix were developed. A record low color temperature of 1722 K OLED radiation was achieved, which is by 80 K lower than that of the best devices reported previously.

scholarly journals DAMPAK PERUBAHAN TEMPERATUR WARNA LAMPU FLUORESEN PADA PRODUKTIVITAS MENGGAMBAR ARSITEKTUR MANUAL MAHASISWA DI STUDIO GAMBAR

2018 ◽  
Vol 1 (2) ◽  
pp. 211
Author(s):  
LEONARDO .
Keyword(s):  
Experimental Approach ◽  
Lighting Design ◽  
Daily Activities ◽  
Color Temperature ◽  
Design Criteria ◽  
Design Institute ◽  
Lighting Condition ◽  
Colour Temperature ◽  
Artificial Lighting ◽  
Short Period

All artificial lightings have effects on human daily activities. Psychologically, warm colour temperature gives relaxation feelings and cool colour temperature promotes alertness to most activities. This present study aims to describe the alteration of colour temperature from artificial lighting on manual students drawing productivity in drawing studio within a short period. A semi-experimental approach is conducted in two studios on a par for two days, involving 26 students of sixth semester to draw a set of interior details to finish in five hours each session on the same time. Each studio is installed with fluorescent tube lamps with different colour temperature for each session. The drawing elements comprehensiveness and the drawing quality are examined to assess lighting condition in the studios. Findings show that the alteration of colour temperature from 2700K to 6500K is significantly positive to productivity while mix of 4000K and 6500K to 4000K is not significant. The benefit of this study leads to reference to lighting design criteria for drawing studio in design institute to enable students to work in a prolonged time without eye overburden. Hence the design brings positive output. Keywords : artificial lighting; color temperature; drawing; manual drawing;productivity; qualification

scholarly journals PENGARUH KENYAMANAN VISUAL MELALUI PENCAHAYAAN BUATAN PADA MASJID SYAMSUL ULUM UNIVERSITAS TELKOM, BANDUNG

2017 ◽  
Vol 1 (2) ◽  
pp. 129
Author(s):  
Andika Putri Pertiwi ◽  
Ahmad Nursheha Gunawan
Keyword(s):  
Color Temperature ◽  
Colour Temperature

Masjid merupakan sarana ibadah umat muslim yang dapat menampung jamaah dalam jumlah banyak, seiring waktu dan tuntutan kebutuhan aktifitas, masjid memiliki fungsi lain yang tidak hanya digunakan sebagai tempat beribadah tetapi juga sebagai sarana bersosialisasi baik secara vertikal maupun horizontal, permasalahan yang timbul adalah berkembangnya beragam aktivitas kegiatan dari peruntukan desain awal yang dibuat, salah satunya adalah konsep awal pencahayaan buatan yang diaplikasikan pada masjid dengan fungsi utama sebagai penunjang suasana sarana ibadah tidak dapat memberikan kenyamanan visual bagi user yang menggunakan masjid sebagai tempat kajian ilmu dan area untuk baca tulis al-quran. Penelitian yang dilakukan adalah jenis penelitian deskriptif kualitatif, yaitu pencarian fakta mengenai tingkat kenyamanan visual yang dipengaruhi pencahayaan buatan dengan objek penelitian ruang utama jamaah laki laki Masjid Syamsul Ulum Telkom University untuk penunjang kegiatan non ibadah seperti membaca dan menulis , dengan metode observasi, dokumentasi, wawancara dan pengukuran alat berupa luxmeter untuk mengetahui kualitas cahaya di beberapa titik yang dipetakan dengan pembagian area berdasarkan tingkat paparan cahaya pada area tersebut. Hasil observasi dan wawancara menunjukkan bahwa ukuran cahaya dalam ruangan masih jauh dibawah standar kenyamanan visual, pengguna yang beraktifitas di ruang utama jamaah laki-laki merasa pencahayaan buatan yang kurang memadai untuk aktifitas seperti membaca dan menulis. Hasil pengukuran dengan alat luxmeter menunjukkan tingkat pencahayaan yang ada belum sesuai dengan standar penerangan minimal untuk sarana rumah ibadah dengan ketinggian ceiling diatas 6 meter adalah 200 lux dan untuk kegiatan belajar ruang kelas / perpustakaan beradadiantara 250-300 lux. Rekomendasi untuk memberi kenyamanan visual pada aktifitas membaca dan menulis adalah merancang tipe pencahayaan setempat (localize lighting) pada area bekerja visual spesifik yang membutuhkan intensitas cahaya lebih tinggi dengan colour temperature cool light. Sementara itu untuk area sholat tetap dapat menggunakan tipe pencahayaan merata (general lighting) dengan color temperature warm light yang menjadi aksen dengan tetap menggunakan colour temperature cool light sebagai renderasi cahaya utama.

scholarly journals Temperature and Mass Profile of Far-infrared Skeleton Nebula

2011 ◽  
Vol 1 ◽  
pp. 1-3
Author(s):  
Binil Aryal
Keyword(s):  
Star Formation ◽  
Flux Density ◽  
Far Infrared ◽  
Density Variation ◽  
Color Temperature ◽  
External Radiation ◽  
Colour Temperature ◽  
Mass Profile ◽  
Dust Grain ◽  
Map Location

Flux density variation of a newly discovered isolated far-infrared interstellar nebula (R.A. = 08h27m, Dec. = +25°54' (J2000)) is studied at 100 μm and 60 μm Infrared Astronomical Survey (IRAS) maps. The nebula contains two bright condensations ("nuclei") and several prominent filaments. The dust color temperature is estimated throughout the nebular region by dividing the 100 μm map by the 60 μm map and comparing the resulting flux I(100μm)/I(60μm) values at each map location with the values given for dust grain models by Dwek (1986). It is found that the dust colour temperature of the southern nucleus is 34±4 K and the temperature of its northern counterpart 32±4 K. The eastern filamentary structures are slightly cooler (20±2 K) than the western filamentary structures (26±3 K). Hence, the locations of the maximum emission i.e. the nuclei of the nebula are warmer than their filaments. It is interestingly noticed that there are no hints of star formation in the nebula, suggesting interaction with ambient matter or the presence of unknown external radiation. Possible explanations of the results will be explained.Key words: Nebula; Temperature; IRASThe Himalayan Physics Vol.1, No.1, May, 2010Page:1-3Uploaded Date: 28 July, 2011

Analysis of Characteristics of Halogen and LED Automobile Lamps

2020 ◽  
pp. 57-62
Author(s):  
Olga Yu. Kovalenko ◽  
Yulia A. Zhuravlyova
Keyword(s):  
Power Consumption ◽  
Flip Chip ◽  
Weather Conditions ◽  
Luminous Flux ◽  
Luminous Efficacy ◽  
Colour Temperature ◽  
Study Results ◽  
Calculation Results ◽  
Mandatory Rules ◽  
Halogen Lamps

This work contains analysis of characteristics of automobile lamps by Philips, KOITO, ETI flip chip LEDs, Osram, General Electric (GE), Gtinthebox, OSLAMPledbulbs with H1, H4, H7, H11 caps: luminous flux, luminous efficacy, correlated colour temperature. Characteristics of the studied samples are analysed before the operation of the lamps. The analysis of the calculation results allows us to make a conclusion that the values of correlated colour temperature of halogen lamps are close to the parameters declared by manufacturers. The analysis of the study results has shown that, based on actual values of correlated colour temperature, it is not advisable to use LED lamps in unfavourable weather conditions (such as rain, fog, snow). The results of the study demonstrate that there is a slight dispersion of actual values of luminous flux of halogen lamps by different manufacturers. Maximum variation between values of luminous flux of different lamps does not exceed 14 %. The analysis of the measurement results has shown that actual values of luminous flux of all halogen lamps comply with the mandatory rules specified in the UN/ECE Regulation No. 37 and luminous flux of LED lamps exceeds maximum allowable value by more than 8 %. Luminous efficacy of LED lamps is higher than that of halogen lamps: more than 82 lm/W and lower power consumption. The results of the measurements have shown that power consumption of a LED automobile lamp is lower than that of similar halogen lamps by 3 times and their luminous efficacy is higher by 5 times.

The Influence Of The Led Luminaires Electrical Parameters On Their Correlated Colour Temperature During Operation Mode

2020 ◽  
pp. 89-96
Author(s):  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov ◽  
Sergei V. Prytkov ◽  
Sergei Yu. Grigorovich ◽  
Anastasia V. Kapitonova ◽  
...  
Keyword(s):  
Operation Mode ◽  
Light Sources ◽  
Electrical Parameters ◽  
Colour Temperature ◽  
Radiation Spectra ◽  
Service Period ◽  
Close Proximity ◽  
Definition Of ◽  
Comprehensive Study

The article describes the results of comprehensive study aiming at increase of quality of LED luminaires and definition of the nature of changes in their correlated colour temperature (CCT) in the course of operation. Dependences of CCT of LED luminaires with remote and close location of phosphor for 10 thousand hours of operation in different electric modes were obtained; the results of comparison between the initial and final radiation spectra of the luminaires are presented; using mathematical statistics methods, variation of luminaire CCT over the service period claimed by the manufacturer is forecast; the least favourable electric operation modes with the highest CCT variation observed are defined. The obtained results have confirmed availability of the problem of variation of CCT of LED luminaires during their operation. Possible way of its resolution is application of more qualitative and therefore expensive LEDs with close proximity of phosphor or LEDs with remote phosphor. The article may be interesting both for manufacturers and consumers of LED light sources and lighting devices using them.

scholarly journals Constant Optical Power Operation of an Ultraviolet LED Controlled by a Smartphone

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4707
Author(s):  
Ching-Hua Chen ◽  
Jia-Jun Zhang ◽  
Chang-Han Wang ◽  
Yu-Chia Chang ◽  
Pinghui S. Yeh
Keyword(s):  
Uv Light ◽  
Light Output ◽  
Color Temperature ◽  
Constant Light ◽  
Driving Voltage ◽  
Light Power ◽  
Monolithically Integrated ◽  
Uv Led ◽  
Power Operation ◽  
Arduino Uno

Constant light power operation of an ultraviolet (UV) LED based on portable low-cost instrumentation and a monolithically integrated monitoring photodiode (MPD) has been reported for the first time. UV light irradiation has become one of the essential measures for disinfection and sterilization. Monitoring and maintaining a specified light power level is important to meet the criteria of sterilization. We built a module composed of a monolithically integrated UV LED and MPD, a transimpedance amplifier, an Arduino Uno card, a digital-to-analog converter and a Bluetooth transceiver. An Android App that we wrote remotely controlled the UV LED module via Bluetooth. The Arduino Uno card was programmed to receive demands from the smartphone, sent a driving voltage to the LED and returned the present MPD voltage to the smartphone. A feedback loop was used to adjust the LED voltage for maintaining a constant light output. We successfully demonstrated the functioning of remote control of the App, and the resultant UV LED measured power remained the same as the setting power. This setup can also be applied to visible or white LEDs for controlling/maintaining mixed light’s chromaticity coordinates or color temperature. With such controlling and internet capability, custom profiling and maintenance of precision lighting remotely would be possible.

scholarly journals The effects of short-term light exposure on subjective affect and comfort are dependent on the lighting time of day

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lijun Chen ◽  
Fang-Fang Yan ◽  
Shuhan Fan ◽  
Yifan Wu ◽  
Jia Yang ◽  
...  
Keyword(s):  
Significant Role ◽  
Negative Correlation ◽  
Significant Interaction ◽  
Daily Life ◽  
Light Exposure ◽  
Time Of Day ◽  
Color Temperature ◽  
Subjective Feeling ◽  
Short Term ◽  
Illuminance Level

AbstractLight, one of the key environmental components for both life and work, played significant role in subjective feelings (e.g. affect and comfort), but the exact effects and mechanisms were still to be determined. The present study screened thirty healthy adults (13 females, 22.45 ± 3.26 years) and examined subjective affect and comfort under short-term white lights with different combination of correlated color temperature (CCT) and illuminance at different times of day (e.g. morning, afternoon, and evening). Our results showed a significant interaction between illuminance level and time-of-day on subjective comfort. Participants felt more comfortable under 50 lx and 100 lx instead of 500 lx in the evening, and more comfortable under 500 lx in the morning and afternoon. In addition, a positive correlation between illuminance and comfort in the morning and a negative correlation between them in the evening were found. No significant effect of CCT on any subjective feeling was revealed. Our results necessitate the consideration of time-of-day in understanding lighting effects and application of healthy lighting in daily life.

scholarly journals Light Output, Thermal Properties, and Reliability of Using Glass Phosphors in WLED Packages

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 239
Author(s):  
Chin-Chuan Huang ◽  
Tsung-Han Weng ◽  
Chun-Liang Lin ◽  
Yan-Kuin Su
Keyword(s):  
Thermal Properties ◽  
Yttrium Aluminum Garnet ◽  
Saturated Vapor ◽  
Light Output ◽  
Junction Temperature ◽  
Color Temperature ◽  
Light Emitting ◽  
Chromaticity Coordinate ◽  
White Light Emitting Diodes ◽  
Color Rendering

White-light-emitting diodes (WLED) based on yttrium aluminum garnet (YAG) phosphors sintered with glass (PiG) and with silicone (PiS) are compared in terms of their light properties, temperature properties and reliability.The complete YAG phosphor was doped with an encapsulant traditional WLED (PiS WLED), and the WLED was covered with PiG (PiG WLED). PiG was made by sintering glass powder and YAG phosphor at the ratio of 87:13 (%), and the correlated color temperature (CCT) was 5564 K. The CCT of the PiG WLED with the YAG doping concentration of 8.5 wt.% approximated 5649 K. The initial light output of the PiG WLED was 6.4% lower than that of the PiS WLED. Under 1008 h and 350 mA aging, PiG WLED and PiS WLED’ light output, CCT and color rendering index variation rates were all within 1%. In the saturated vapor-pressure test, no sample exhibited red ink infiltration, light nor peeling between the encapsulant and the lead-frame. Compared with that of the PiS WLED, the junction temperature of the PiG WLED reduced from 88.4 °C to 81.3 °C. Thermal resistance dropped from 37.4 °C/W to 35.6 °C/W. The PiG WLED presented a better CIE (Commission Internationale de l’Eclairage) 1931 chromaticity coordinate (x,y) concentration and thermal properties than the PiS WLED.

Sign in / Sign up

Export Citation Format

Share Document