A Continuous Rectangular-Wave Method for Junction Temperature Measurement of Light-Emitting Diodes

Liu, Ze-Hui; Huang, Jia-En; Gao, Yue; Guo, Ziquan; Lin, Yue; Zhu, Lihong; Zhong, Cheng; Lu, Yijun

doi:10.1109/tpel.2019.2904149

Cited by 8 publications

(6 citation statements)

References 20 publications

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“…C. Temperature-Dependent Optical Characteristics for RGB Mini-LEDs By using the proposed method, we can perform the research on the temperature-dependent optical properties and color performances of a single Mini-LED in the display. The working temperature and driven current are two significant factors to affect the optical properties of LEDs, especially the IEEE Journal of The Electron Device Society miniaturized and integrated Mini-/Micro-LEDs [20], [21]. Therefore, it is necessary to study the influence of working temperature and driven current on Mini-LEDs and Micro-LEDs.…”

Section: B Comparison Of Proposed Methods and Traditional Methodsmentioning

confidence: 99%

Proposing an Accurate and Fast Optical Batch Inspection Method of Mini-/Micro-LEDs

Li,

Huang,

Cao

et al. 2024

IEEE J. Electron Devices Soc.

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Based on the microscopic hyperspectral imaging technique, an optical batch inspection method has been proposed by the authors to efficiently and precisely obtain the absolute emission spectra of red (R), green (G), and blue (B) Mini-/Microlight-emitting diodes (Mini-/Micro-LEDs). The RGB Mini-LEDs (with a chip area of 200 µm × 100 µm) based array is selected for carrying out this experiment. Via the proposed method, the photometric and colorimetric properties of each Mini-LED pixel could be derived in detail. In this proposed method, an optimized Canny-based algorithm has been used for quickly detecting the effectively emitting area in the collected hyperspectral images, thus saving more time for workers. While compared with the traditional integrating-sphere-based method, the measured data between the proposed method and traditional method are in fairly good consistence, with their maximum deviation of < 3.2%. The external quantum efficiency (EQE) and chromaticity coordinates of each Mini-LED are acquired at the temperature ranging from 300 K to 340 K by the proposed method. Three RGB Micro-LEDs (with a chip area of 10 μm × 10 μm) based arrays are also selected for the optical batch detection, and the pseudocolor maps of normalized electroluminescence (EL) intensity for RGB Micro-LEDs are analyzed. Finally, the optical crosstalk of RGB Mini-LEDs is quantitatively defined and analyzed. The optical crosstalk effects are more prominent for red Mini-LEDs than the other two. Results indicate that the proposed method has shown potential applications in the field of Mini-/Micro-LEDs' batch inspection. Index Terms-Mini-/Micro-LED, microscopic hyperspectral imaging, optical batch inspection, edge detection I.

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Section: B Comparison Of Proposed Methods and Traditional Methodsmentioning

confidence: 99%

Proposing an Accurate and Fast Optical Batch Inspection Method of Mini-/Micro-LEDs

Li,

Huang,

Cao

et al. 2024

IEEE J. Electron Devices Soc.

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“…Consequently, the conventional forward voltage method (FVM) tends to yield lower junction temperature readings. To mitigate the limitations of FVM, Ze-Hui Liu et al proposed the continuous rectangular-wave method (CRWM) [39].…”

Section: Continuous Rectangular-wave Methods (Crwm)mentioning

confidence: 99%

“…There have been several reviews covering general temperature measurement techniques [28], semiconductor temperature measurement [29,30], and various electronic modules [31][32][33][34]. Numerous methods have been proposed for detecting the thermal characteristics of LEDs, with existing junction temperature measurement methods primarily focused on identifying temperature-sensitive parameters (TSPs), including temperature-sensitive electrical parameters (TSEPs) and temperature-sensitive optical parameters (TSOPs) [35][36][37][38][39]. Various LED junction temperature detection methods are prevalent in mainstream research.…”

Section: Introductionmentioning

confidence: 99%

LED Junction Temperature Measurement: From Steady State to Transient State

Zhao,

Gong,

Zhu

et al. 2024

Sensors

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In this review, we meticulously analyze and consolidate various techniques used for measuring the junction temperature of light-emitting diodes (LEDs) by examining recent advancements in the field as reported in the literature. We initiate our exploration by delineating the evolution of LED technology and underscore the criticality of junction temperature detection. Subsequently, we delve into two key facets of LED junction temperature assessment: steady-state and transient measurements. Beginning with an examination of innovations in steady-state junction temperature detection, we cover a spectrum of approaches ranging from traditional one-dimensional methods to more advanced three-dimensional techniques. These include micro-thermocouple, liquid crystal thermography (LCT), temperature sensitive optical parameters (TSOPs), and infrared (IR) thermography methods. We provide a comprehensive summary of the contributions made by researchers in this domain, while also elucidating the merits and demerits of each method. Transitioning to transient detection, we offer a detailed overview of various techniques such as the improved T3ster method, an enhanced one-dimensional continuous rectangular wave method (CRWM), and thermal reflection imaging. Additionally, we introduce novel methods leveraging high-speed camera technology and reflected light intensity (h-SCRLI), as well as micro high-speed transient imaging based on reflected light (μ_HSTI). Finally, we provide a critical appraisal of the advantages and limitations inherent in several transient detection methods and offer prognostications on future developments in this burgeoning field.

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“…A number of methods have been proposed to detect the LED thermal characteristics. The key point of existing junction temperature measurement methods usually lies in seeking the temperature-sensitive parameters (TSPs), including the temperature-sensitive electrical parameter (TSEP) and the temperature-sensitive optical parameter (TSOP) [ 6 , 7 , 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Transient 2D Junction Temperature Distribution Measurement by Short Pulse Driving and Gated Integration with Ordinary CCD Camera

Wang

Gong

Zhuang³

et al. 2022

Sensors

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The time resolution of the transient process is usually limited by the minimum exposure time of the high-speed camera. In this work, we proposed a method that can achieve nanosecond temporal resolution with an ordinary CCD camera by driving the LED under test with a periodic short-pulse signal and multiple-cycle superposition to obtain two-dimensional transient junction temperature distribution of the heating process. The temporal resolution is determined by the pulse width of the drive source. In the cooling process, the Boxcar gated integration principle is adopted to complete the two-dimensional transient junction temperature distribution with temporal resolution subject to the minimum exposure time of the CCD camera, i.e., 1 μs in this case. To demonstrate the validity of this method, we measured the two-dimensional transient junction temperature distribution of the blue LEDs according to the principle of thermoreflectance and compared it with the thermal imaging method.

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A Continuous Rectangular-Wave Method for Junction Temperature Measurement of Light-Emitting Diodes

Cited by 8 publications

References 20 publications

Proposing an Accurate and Fast Optical Batch Inspection Method of Mini-/Micro-LEDs

Proposing an Accurate and Fast Optical Batch Inspection Method of Mini-/Micro-LEDs

LED Junction Temperature Measurement: From Steady State to Transient State

Transient 2D Junction Temperature Distribution Measurement by Short Pulse Driving and Gated Integration with Ordinary CCD Camera

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