Two-Dimensional Transient Temperature Distribution Measurement of GaN Light-Emitting Diode Using High Speed Camera

Abstract

We put forward a non-contact method for determining the transient two-dimensional (2D) temperature distribution of light emitting diodes (LEDs). A high-speed camera is employed to acquire the 2D reflective light of blue LED under test (468 nm) illuminated by a red LED (690 nm) as the incident light source to avoid the band-gap modulation effect. The 2D transient temperature distribution is derived in terms of temperature-dependent reflective light intensity relationship. Two cases are studied to test the system in this work under (1) 1980 fps frame rate with time resolution of 505 µs at 300 mA, and (2) 5600 fps with time resolution of 179 µs at 500 mA. Compared with the conventional infrared thermal imaging (TI) method, the spatial resolution and the time resolution of this proposed method increase up to one and two orders of magnitude, respectively.

Afterglow-intensity-ratio-based temperature sensing using a persistent phosphor

“…Temperature is one of the most basic physical parameters, and its precise measurement plays a vital role in scientific research, industrial production, life sciences, etc. 1–3 Conventional temperature-sensing techniques can be divided into two categories: contact type methods, which include resistance temperature detectors, thermocouples, and thermistors, 4 and non-contact type methods, which include infrared thermal imaging, thermal reflection, 5 Raman spectroscopy, 6 and so on. In recent years, non-contact optical thermometers based on steady-state fluorescence for biological sensing, 7 catalytic reactions 8 and rapid monitoring of the temperature of a free fluid 9 have gradually become an important branch of the thermometry technique due to their convenience, rapid response, high sensitivity, and high temperature and spatial resolution.…”

LED Junction Temperature Measurement: From Steady State to Transient State

“…Subsequently, employing the negative linear relationship between reflection intensity and temperature, the corresponding two-dimensional transient thermal characteristics can be derived, particularly during the heating and cooling processes. Figure 16 showcases a series of transient two-dimensional temperature distributions using the h-SCRLI method during the rising edge of the driving current, along with a comparison with the transient response of the thermal reflection imaging method [17]. Figure 16 exhibits a sequence of transient 2D temperature distributions of the LUT utilizing the h-SCRLI method during the rising edge of the drive current.…”

“…Thus, the PN junction temperature of an LED is a critical parameter for evaluating its performance, determining its service life, and ensuring its stability [14][15][16]. An increase in LED junction temperature can adversely affect luminous efficiency, underscoring the importance of its testing for semiconductor devices [17,18]. Preserving LED performance necessitates maintaining the junction temperature at a reasonable level.…”

A Critical Review on the Junction Temperature Measurement of Light Emitting Diodes

“…In one of the latest studies, the reflective light intensity change of a blue GaN LED was exploited to derive the 2D transient temperature distribution of the operating device [ 144 ]. In contrast to other studies, the authors captured light reflection with a high-speed camera with a 505 μs to 68 μs time resolution range.…”