TY - GEN

T1 - Temperature issues with white laser diodes, calculation and approach for new packages

AU - Lachmayer, Roland

AU - Kloppenburg, Gerolf

AU - Stephan, Serge

PY - 2015/1/6

Y1 - 2015/1/6

N2 - Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class systems mainly use HID or LED light sources. As a further step laser diode based systems offer a high luminance, efficiency and allow the realization of new dynamic and adaptive light functions and styling concepts. The use of white laser diode systems in automotive applications is still limited to laboratories and prototypes even though announcements of laser based front lighting systems have been made. But the environment conditions for vehicles and other industry sectors differ from laboratory conditions. There for a model of the system's thermal behavior is set up. The power loss of a laser diode is transported as thermal flux from the junction layer to the diode's case and on to the environment. There for its optical power is limited by the maximum junction temperature (for blue diodes typically 125 - 150°C), the environment temperature and the diode's packaging with its thermal resistances. In a car's headlamp the environment temperature can reach up to 80°C. While the difference between allowed case temperature and environment temperature is getting small or negative the relevant heat flux also becomes small or negative. In early stages of LED development similar challenges had to be solved. Adapting LED packages to the conditions in a vehicle environment lead to today's efficient and bright headlights. In this paper the need to transfer these results to laser diodes is shown by calculating the diodes lifetimes based on the presented model.

AB - Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class systems mainly use HID or LED light sources. As a further step laser diode based systems offer a high luminance, efficiency and allow the realization of new dynamic and adaptive light functions and styling concepts. The use of white laser diode systems in automotive applications is still limited to laboratories and prototypes even though announcements of laser based front lighting systems have been made. But the environment conditions for vehicles and other industry sectors differ from laboratory conditions. There for a model of the system's thermal behavior is set up. The power loss of a laser diode is transported as thermal flux from the junction layer to the diode's case and on to the environment. There for its optical power is limited by the maximum junction temperature (for blue diodes typically 125 - 150°C), the environment temperature and the diode's packaging with its thermal resistances. In a car's headlamp the environment temperature can reach up to 80°C. While the difference between allowed case temperature and environment temperature is getting small or negative the relevant heat flux also becomes small or negative. In early stages of LED development similar challenges had to be solved. Adapting LED packages to the conditions in a vehicle environment lead to today's efficient and bright headlights. In this paper the need to transfer these results to laser diodes is shown by calculating the diodes lifetimes based on the presented model.

KW - Automotive lighting

KW - Laser

KW - Laser activated remote phosphor

KW - Lifetime modeling

KW - Thermal management of laser diodes

UR - http://www.scopus.com/inward/record.url?scp=84923013244&partnerID=8YFLogxK

U2 - 10.1117/12.2070411

DO - 10.1117/12.2070411

M3 - Conference contribution

AN - SCOPUS:84923013244

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Photonics, Devices, and Systems VI

A2 - Senderakova, Dagmar

A2 - Tomanek, Pavel

A2 - Tomanek, Pavel

A2 - Pata, Petr

A2 - Pata, Petr

PB - SPIE

T2 - Photonics, Devices, and Systems VI

Y2 - 27 August 2014 through 29 August 2014

ER -