Lighting Research Group (LRG) is composed of the scientists, young researchers and students at Vilnius University. This group was established in cooperation of Institute of Applied Research and Department of Mathematics and Informatics. The group is led by the professors Artūras Žukauskas and Rimantas Vaicekauskas.
The group’s objective is to promote world-class research activities in the field of solid-state lighting. We work on characterization, optimization and applications of the light-emitting diodes (LED) and their systems in general and niche lighting. LRG is focused on LEDs clusters and systems optimization by varying spectral power distributions. The equipment (including software) possessed by the researchers allow ones to perform a full scale characterization, modeling and optimization of the optical, electrical and thermal characteristics of the LEDs and small LED based systems. We specialize in the lighting systems with advanced color properties (controllable color saturating, and fidelity) for general lighting as well as lighting systems for improved nutritional quality vegetable growth. The research and modeling of the intelligent solid-state lighting systems for outdoor lighting also occupies a significant part of our scientific interest.
Services offered to the industry and scientific partners:
1. Investigation of the following optical characteristics of the light sources (lamps, LEDs and other.):
a) luminous and radiant flux;
b) colour coordinates;
c) colour rendering indexes;
d) colour quality judgement according to the statistical colour quality approach;
e) efficiency of reflective and refractive optical elements;
f) angular distribution of the emission;
g) illuminance (lx) and luminance (cd/m2) of the illuminated surfaces;
h) Investigation of street lighting according to the LST-EN-13201-3 standard.
2. Solid-state light source spectral power distribution optimization:
a) Luminous efficacy (lm/W);
b) luminous efficiency (lm/W);
c) colour rendition (CRI, GAI, SQC, Statistical approach);
d) correlated colour temperature;
e) circadian action factor;
f) photochemical damage;
g) plant lighting;
h) dichromatic, trichromatic and tetrachromatic clusters optimization;
3. Digital simulation and optimization of optical systems by Monte Carlo ray trace software.
4. Investigation of the following thermal characteristics of the LEDs and LED based systems:
a) LED junction temperature remote measurements;
b) thermal resistance;
c) thermal relaxation constants;
d) investigation of heat management systems by fast and high resolution thermovision.
5. Digital simulation and optimization of heat transfer processes in optoelectronics and electronics.
6. Investigation of the following electrical characteristics of the LEDs and LED based systems:
d) efficiency (wall plug);
e) power factor, distortions by high frequency harmonics and other characteristics of AC power loads;
f) Investigation on dimming algorithms (Pulse width modulation, frequency modulation, constant current and etc.).
7. Accelerated life-tests of optoelectronic devices and systems in constant climate (temperature and humidity) chamber.
8. Design and simulation of niche light sources with the ability of controllable colour saturation and fidelity.
9. Design, modelling and prototyping of custom solid-state light sources for niche applications (green houses, windows and other retail places).
10. Design and prototyping of microcontroller based power sources with remote control option (PLC, IR or Wifi).
11. Design of fluorescence sensors with deep-UV (>230 nm) LEDs used for excitation.
12. Consultancy in the field of solid-state lighting and characterization.