STATE OF THE ART AND PROSPECTS FOR THE EVOLUTION OF WHITE LEDS WITH NEAR NATURAL LIGHT EMISSION

Abstract

Innovative technologies for the production of modern LEDs have allowed leading manufacturers (Seoul Semiconductor, Samsung, Cree) to develop their own ways of producing highly efficient white LEDs characterised by radiation parameters close to natural light. Modern LED light source development technologies have led to a sharp decrease in the use of white light guides with a colour rendering index in the range of 70-75, while the new most efficient LEDs have a colour rendering index of at least 80, and LEDs with a colour rendering index of more than 90 are becoming more widely used. LEDs with a correlated colour temperature in the range of 3000-4500 K, which were not as commonly used before due to their lower efficiency, have become more widespread. To create energy-efficient lighting, it is now considered important to create LED lighting devices with a spectral composition of radiation close to white natural light, as it is the most acceptable for improving the psycho-physiological state of a person and adequate perception of the environment. The most comfortable and safe for humans is the value of the correlated colour temperature of light close to 4000-4500 K and the colour rendering index of more than 90 units. Leading lighting companies are successfully working on solving this problem. This paper analyses ways to improve the luminous efficiency and colour rendering index of white LEDs used by leading manufacturers of modern LEDs. The most efficient white LEDs with a colour rendering index in the range of 93-96 and a luminous efficiency of 105-200 lm/W are considered. In the face of fierce competition, leading manufacturers are addressing the issue of improving the quality of LED lighting equipment in their own ways, which ensures the continuous development of LED technologies. The maximum theoretically determined spectral efficiencies of white LEDs are about 370 lm/W, which may indicate possible significant achievements and significant prospects for the further development of LED lighting technology.