LED TECHNOLOGIES DEPARTMENT

Thermal management

LED crystals are much more sensitive to high temperatures compared to other light sources. LED efficiency and its lifetime drop rapidly with the temperature increase in the LED active region and in the phosphor layer. Practicable upper temperature limit is about 80 °С. The actual high power LED efficiency rarely approaches 40%, which, taking into account their relatively small size, provides for high heat flux per LED mounting area.

This factor leads to several problems which need solutions:

  • Creation of substrates for chip-on-board (COB) LEDs, cases and mounting techniques providing the lowest thermal resistance;
  • Creation of complex heat management systems fitting LED heat mode.

These issues are solved through heat transfer and fluid dynamics numerical simulations using CAE software. As the result of modeling, most appropriate materials are chosen and heat dissipation system constructions are improved.

In order to solve the first problem, heat transfer study for COB with substrates, made of various materials was done. COB substrate thermal resistance and thermal resistance of different mounting ways were evaluated. As the result for the leading Optogan COB project X10 Al2O3 substrate and the best mounting ways were chosen.

In particular, X10 geometric parameters optimization task for different materials was performed. Temperature distribution for X10 is shown in the picture below. This study was devoted to choosing the optimal thickness of the X10 substrate. The project also looked into different substrate material and mounting glue impact.

 

One of the “Optogan. New Technology of Light” aims is to create and upgrade retrofit lamps for E27 socket. To effectively achieve this aim we need to create effective  heat sinks with a small form-factor. For this reason the company studies different heat sinks materials and designs.

Thermoconductive plastics are used for the production of new heat sinks. Design of the heat management part of the lamp is shown in the picture below.

 

The improvement of heat sink dissipation is achieved due to heat sink geometry optimization. . New designs with complex multi material structure are also being studied to use maximum potential of the thermo conductive plastics.