The dramatic increase of electronic components and devices in passenger cars tends to result in a further miniaturization of these components. In this context the chip on board technology of semiconductor devices and semiconductor light sources without extern housing and without extern optic devices gains importance. Not only the required space of further developed optoelectronic devices could be critical but also the consumption of electrical energy must be decreased. As this paper shows a direct encapsulation of Light emitting diodes (LEDs) by dint of an injection molding tool is possible. Forming the optical geometry to gain the required radiation pattern within this encapsulation process has been proofed to be feasible. In a first approach we investigated a two step encapsulation process but with the further development we ascertained a similar drop out rate for a single step encapsulation process. In particular with regard to the processing of temperature sensitive semiconductor devices specific knowledge on the thermal load is required for product life-time estimation. Therefore temperature measurement during the encapsulation process is a key point.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.