The light-emitting diode of an LED package radiates light and heat according to the input power. However, the surface area of an LED package is quite small,and the package itself is expected to release little heat into the atmosphere.An external radiator such as a heat sink is thus required.The heat dissipation structure up to the connection portion of the external radiator uses mainly heat conduction.
This document provides technical information regarding the heat dissipation design of the CITIZEN CLLO40 Series Light Engine. It explains that due to the small surface area of LED packages, an external radiator such as a heat sink is required to release heat efficiently into the atmosphere.
The datasheet details the package structure, noting that the light-emitting diode is mounted directly on a well-conductive aluminum substrate rather than an insulating layer. This design minimizes thermal resistance (Rj-c), allowing efficient conduction of generated heat to the external radiator via die-mounting adhesive and heat-dissipation grease.
The absolute maximum rating for the junction temperature is 150°C.
The outline dimensions of the heat sink are 64mm wide by 40mm high.
The thickness of the heat conductive sheet is 0.12mm.