In recent times, the transportation industry has generated a number of developments involving new technology in signaling. Important developments have involved the production of light by means of light emitting diode (LED). Since the heat from the junction must be dissipated into the ambient somehow, changing the ambient temperature affects the junction temperature and hence the emitted light. When the LEDs have been used in the railway or traffic signals, the optical proprieties of these have to maintain more rigorous specifications. The junction temperature of the power LEDs affects the device's luminous flux of the device. In this paper, we describe problems of the temperature dependent changes of LED intensity. Besides we will introduce an innovative technical to allow the use of the LEDs in applications with rigorous specifications.

Date Published: 11 October 2011
PDF: 7 pages
Proc. SPIE 8306, Photonics, Devices, and Systems V, 83061N (11 October 2011); doi: 10.1117/12.912384

Published in SPIE Proceedings Vol. 8306:
Photonics, Devices, and Systems V
Pavel Tománek; Dagmar Senderáková; Petr Páta, Editor(s)