Development of a LED light therapy device with power density control using a Fuzzy logic controller
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Updated: Nov 27, 2025

Development of an Innovative LED-based Illumination Device for In Vitro Application of Photodynamic Therapy with Rose Bengal
Published on: September 12, 2025
Duc Tri Phan1, Ngoc Thang Bui1, Tan Hung Vo1
1Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Republic of Korea.
Abstract:
The biological effects of a light-emitting diode (LED) light therapy device are determined by irradiation parameters, mainly wavelength and power density. However, using a battery to provide power causes a problem in the variation of LED power density during battery discharge. As a result, maintaining a stable LED power density, along with extending battery life and operating time, are the primary concerns in designing a LED light therapy device. The present study aims to introduce a LED light therapy device design with different LED color power density control. A Fuzzy logic, based on the relationship between LED power density and operating time, was proposed to control constant power density in this design. The experimental results demonstrate that by using the designed controller, the LED light therapy device's power density (40 mW/cm2, 50 mW/cm2, 60 mW/cm2 for red, blue, and green light, respectively) can be controlled. The newly designed LED light therapy device could be considered an advanced version with energy savings and stabilized LED power emitting property under a broad range voltage variation.
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