A Novel Silicon-Based LED Packaging Module With an Integrated Temperature Sensor

Abstract

The thermal management of light-emitting diode (LED) packaging modules has become more important in the past decade, especially for high-powered LED chips, which produce high temperatures during lighting, resulting in luminance decay and color temperature drift. For this issue, this paper proposes a novel silicon-based LED packaging module with an integrated temperature sensor. The LED die is mounted directly on a silicon substrate with a resistive nickel/titanium bilayer temperature sensor, which monitors the temperature variations in the LED inside the package, in real time. The thermal conductivity characteristics and the sensor performance for the specified packaging modules are evaluated using finite element analysis and by experiment. The experimental results shows that when the thickness of the bilayer sensing film and its equivalent length, within a sensing area of 1.4 $\,\times\,$ 1.4 ${\rm mm}^{2}$ , are 0.2 $\mu{\rm m}$ and 72.3 mm, respectively, a high sensitivity measurement of 30.4 $\Omega/^{\circ}{\rm C}$ is obtained and good linear output is achieved, at a working temperature for the LED of less than 120 $^{\circ}{\rm C}$ . A miniaturized, integrated, low-cost smart LED packaging module is implemented using this co-packaging method.