LEDs are now mostly used in light projection systems due to their low power requirements, long life and robustness. Here’s an app note from OSRAM for proper integrations on these projection LEDs. Link here (PDF)
This application note provides insights into the use of LED light sources for projection applications. An overview of LED projection systems and their benefits is presented, along with a summary of OSRAM Opto Semiconductors LEDs suitable for these applications. Finally, fundamental design issues related to the use of LEDs in projection modules are addressed.