Sensor Fabrication Method for in Situ Temperature and Humidity Monitoring of Light Emitting Diodes

Chi-Yuan Lee,Ay Su,Chia-Hung Lin,Yin-Chieh Liu,Pin-Cheng Chan

doi:10.3390/s100403363

Abstract

In this work micro temperature and humidity sensors are fabricated to measure the junction temperature and humidity of light emitting diodes (LED). The junction temperature is frequently measured using thermal resistance measurement technology. The weakness of this method is that the timing of data capture is not regulated by any standard. This investigation develops a device that can stably and continually measure temperature and humidity. The device is light-weight and can monitor junction temperature and humidity in real time. Using micro-electro-mechanical systems (MEMS), this study minimizes the size of the micro temperature and humidity sensors, which are constructed on a stainless steel foil substrate (40 μm-thick SS-304). The micro temperature and humidity sensors can be fixed between the LED chip and frame. The sensitivities of the micro temperature and humidity sensors are 0.06 ± 0.005 (Ω/°C) and 0.033 pF/%RH, respectively.

Highlights

Light emitting diodes (LED), which are environmentally friendly, consume little power and have a long lifetime, have caused a revolution in illumination in the 21st century
light emitting diodes (LED) have recently been identified as illumination devices
High-brightness light emitting diodes are being used in an increasing number of lighting applications because of their excellent color saturation and long lifetimes

Summary

Introduction

Light emitting diodes (LED), which are environmentally friendly, consume little power and have a long lifetime, have caused a revolution in illumination in the 21st century. They are favored because of Sensors 2010, 10 their high reliability, low power consumption, and little-to-no-maintenance requirements. An LED is a solid-state semiconductor device that directly converts electrical energy into light. It is a strong candidate for the generation of general illumination applications. The center wavelength, spectrum, power of the light output and reliability of the diode depend directly on the temperature of the junction.

Methods

Results

Conclusion