Design and implementation of real-time LED spatial radiance measurement systems

Gao-Wei Chang; Zong-Mu Yeh; Chia-Cheng Liao

doi:10.1117/12.701665

13 February 2007 Design and implementation of real-time LED spatial radiance measurement systems

Gao-Wei Chang, Zong-Mu Yeh, Chia-Cheng Liao

Proceedings Volume 6486, Light-Emitting Diodes: Research, Manufacturing, and Applications XI; 64860K (2007) https://doi.org/10.1117/12.701665
Event: Integrated Optoelectronic Devices 2007, 2007, San Jose, California, United States

Abstract

Light-emitting diodes (LEDs) have been recognized as a generation of new light sources because they possess the properties of energy-saving, environmental protection, long lifetime, and those lacking in conventional lighting. To satisfy the requirements for different applications (e.g., for large-scale displays), determining the spatial radiances of LEDs is important to identifying their viewing angle and utilizing their lighting efficiency. The objective of this paper is to build up a real-time spatial radiance measurement system for LEDs, on the basis of digital signal processing (DSP) techniques. In this paper, the system analysis is given to show the feasibility of this work. Two primary subsystems are devised to perform the real-time measurements. First, in the optoelectronic sensing and signal processing subsystem, a wide-bandwidth photodiode sensing circuit is employed to acquire optical signals at a high speed, and an automatic gain control (AGC) circuit is designed to increase the measurement range. To support high-speed data processing, a DSP-based platform is developed in the subsystem. Second, a light-source rotation scheme is used in the optomechanical subsystem. For performance evaluations, we adopt a standard calibrating light source to test and verify our system. Experimental results indicate that the proposed system gives satisfactory results.

Citation Download Citation

Gao-Wei Chang, Zong-Mu Yeh, and Chia-Cheng Liao "Design and implementation of real-time LED spatial radiance measurement systems", Proc. SPIE 6486, Light-Emitting Diodes: Research, Manufacturing, and Applications XI, 64860K (13 February 2007); https://doi.org/10.1117/12.701665

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KEYWORDS

Amplifiers

Light emitting diodes

Digital signal processing

Light sources

Sensors

Optoelectronics

Resistance

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