Research on Lumen Measurement and Integrated Opto-Electrical Parameter Detection of Various Light Sources

Introduction

With the upgrading of the lighting industry and increasingly stringent energy efficiency regulations, the precision and stability of light output have become core competitiveness of lighting products. Lumen (lm) is the legal unit of luminous flux, which represents the total visible light emitted by a light source per unit time. Lumen measurement is the key basis for evaluating light brightness, luminous efficacy and energy efficiency grade. Traditional testing equipment has shortcomings such as insufficient precision, poor compatibility and low data consistency, which cannot meet the mass detection requirements of various light sources including energy-saving lamps, HID lamps and LED lamps.

Integrated with high-precision CCD spectrometer, one-piece integrating sphere and professional electrical parameter measuring unit, the LISUN LPCE-2(LMS-9000) system can simultaneously complete the measurement of chromaticity, photometry and electrical parameters, covering all mainstream lighting sources. Its test results conform to international and domestic standards such as CIE177, LM-79-19 and GB/T 24824, providing an integrated solution for lumen measurement and full-parameter quality evaluation.

LPCE 2(LMS 9000) Spectrophotometer & Integrating Sphere Test System

Principle and Standard Basis of Lumen Measurement

Basic Principle of Lumen Measurement
Luminous flux is the physical quantity obtained by weighting the radiant flux of a light source with the human eye spectral luminous efficiency function V(λ), with the unit of lumen (lm). In lumen measurement, the integrating sphere collects the full-space optical radiation of the light source. The spectrometer analyzes the spectral distribution, and calculates core photometric parameters including total luminous flux, luminous efficacy and radiant power.

Testing Standard System
The system strictly complies with the following standards to ensure the authority of lumen measurement:
• Photometric standards: CIE-84 Measurement of Luminous Flux, IESNA-LM-63-2
• Chromaticity standards: CIE13.3, CIE177, ANSI-C78.377
• LED specific standards: LM-79-19, LM-79-24, LM-80, GB/T 24824
• Energy efficiency regulations: (EU)2019/2015 ErP Energy Efficiency Labeling Requirements

Testing System and Experimental Scheme

Composition of the Testing System
Core configuration of LISUN LPCE-2(LMS-9000):
• LMS-9000C high-precision CCD spectrometer
•  One-piece integrating sphere (IS-1.5MA/IS-0.3M)
• Digital electrical parameter analyzer, AC/DC power supply
• Standard light source, optical fiber and standard cabinet
•  Bilingual control software in Chinese and English, compatible with Windows 7 to Windows 11, with certified USB driver

Key Technical Parameters

Test Samples and Procedure

Test Samples: energy-saving lamps, fluorescent lamps, HID lamps (high-pressure sodium lamps, high-pressure mercury lamps), cold cathode fluorescent lamps, various LED light sources (bulbs, modules, COB).
Test Procedure:
• Preheat and calibrate the equipment with standard light source verification;
• Install the sample and keep it stably operating for 30 minutes;
• Start lumen measurement, and simultaneously collect luminous flux, luminous efficacy, color temperature, color rendering index, power and power factor;
• Conduct self-absorption correction and temperature compensation;
• Export LM-79 standard test report and archive experimental data.

Lumen Measurement Results and Opto-Electrical Parameters of Various Light Sources

Test Data of Typical Light Sources

Result Analysis
• Consistency of lumen measurement: The one-piece integrating sphere greatly reduces splicing errors. With photometric linearity of ±0.5%, the relative standard deviation of repeated multi-light-source tests is less than 1%.
•  Luminous efficacy comparison: LED products generally achieve luminous efficacy above 110 lm/W, which is superior to traditional light sources. HID lamps own high luminous flux but poor color rendering performance.
•  Chromaticity stability: LED features less than 1.5% color temperature drift and Ra＞90, suitable for high-quality lighting scenarios.
•  Electrical parameters: The system synchronously detects voltage, current, harmonic and power factor, fully meeting the requirements of energy efficiency label application.

System Advantages and Application Value

• High-precision lumen measurement: Refrigerated CCD and low stray light design ensure full-range precision for both low-power and high-power light sources.
•  Multi-light-source compatibility: It covers traditional gas discharge lamps and solid-state lighting, realizing multi-purpose detection to reduce testing cost.
•  Standard compliance: The system can directly generate LM-79, LM-80 and ErP certification reports, adapting to global export and certification detection.
•  Long-term reliability: It supports LM-82 luminous flux maintenance test, and can be matched with temperature-controlled integrating sphere and multi-channel temperature inspection system.

Conclusion

With lumen measurement as the core function, the LISUN LPCE-2(LMS-9000) system realizes automatic integrated detection of opto-electrical parameters for energy-saving lamps, fluorescent lamps, HID lamps, cold cathode fluorescent lamps and LED lamps. Its indicators including wavelength, color temperature, luminous flux and chromaticity coordinate reach internationally advanced level, fully meeting global standards and certification requirements. As an efficient, stable and high-precision testing platform for enterprise R&D, production quality control and third-party inspection, the system is of great engineering value for improving lighting product quality and promoting industrial standardization.