Role of the 3 Meter Integrating Sphere in the LISUN LPCE-2 (LMS-9000) Lighting Test Instrument

Introduction

As LED lighting technology continues to advance rapidly, the demand for precise performance testing of lighting products has grown significantly, particularly for key metrics such as luminous flux, colorimetric parameters, and luminous efficacy. The LPCE-2 (LMS-9000) LED CCD Rapid Photometric and Electrical Comprehensive Testing System, developed by LISUN, is a state-of-the-art testing platform that integrates a high-precision spectroradiometer, an integrating sphere, and an electrical parameter meter. This system is widely used in the research, production, and quality control of LED luminaires. Central to its capabilities is the 3 meter integrating sphere, a critical component that enhances the system’s ability to perform accurate photometric measurements. This article explores in detail the technical principles, functional features, application scenarios, and industry impact of the 3 meter integrating sphere within the LPCE-2 (LMS-9000) system, emphasizing its role in advancing LED lighting testing.

Basic Principles and Role of the 3 Meter Integrating Sphere

An integrating sphere is a spherical device with an internal surface coated with a highly reflective, diffuse material, typically used to measure the luminous flux, spectral characteristics, and other optical parameters of a light source. The working principle of an integrating sphere relies on multiple diffuse reflections of light within its interior, creating a uniform light field that enables accurate measurement of the total light output from a source, regardless of its directionality. Light signals are collected through photometric probes or spectroradiometer ports installed on the sphere’s wall and transmitted to the testing system for analysis.

In the LPCE-2 (LMS-9000) system, the 3 meter integrating sphere (e.g., IS-3.0MT, with a diameter of 3 meters) is a high-performance component specifically designed for testing large light sources or luminaires. Compared to smaller integrating spheres (e.g., 1.5 or 2 meters), the 3 meter integrating sphere can accommodate larger LED luminaires, such as streetlights, floodlights, and high-bay lights, while delivering superior measurement accuracy and stability. Its large size and advanced design make it an essential tool for evaluating high-power LED lighting products, ensuring reliable results in 3 meter integrating sphere-based testing.

Technical Features of the 3 Meter Integrating Sphere in the LPCE-2 (LMS-9000) System

The 3 meter integrating sphere in the LPCE-2 (LMS-9000) system is engineered with advanced design and manufacturing techniques, offering the following technical features that enhance its performance in LED lighting testing:

• Large-Scale Design
The 3 meter integrating sphere, with its 3-meter diameter, is designed to accommodate large LED luminaires, such as streetlights, high-bay lights, and large panel lights, which are common in high-power lighting applications. The increased internal volume reduces the proximity effect between the light source and the sphere’s walls, minimizing measurement errors caused by spatial constraints. This makes the 3 meter integrating sphere ideal for testing high-power LED luminaires, where smaller spheres may introduce inaccuracies due to limited space.
• High-Reflectivity Coating
The interior of the 3 meter integrating sphere is coated with a high-reflectivity diffuse material, such as barium sulfate or PTFE, achieving a reflectance of over 98%. This high reflectivity ensures that light undergoes multiple reflections within the sphere, creating a uniform light field that minimizes light absorption and measurement deviations. The coating enhances the accuracy of luminous flux measurements, a critical aspect of 3 meter integrating sphere testing for large-scale LED luminaires.
• Constant-Temperature Control
The 3 meter integrating sphere is equipped with a constant-temperature control system (e.g., IS-3.0MT constant-temperature integrating sphere), supported by a multi-channel temperature monitoring instrument (TMP-8) that tracks internal and external temperatures in real time. Stable temperature control is essential for 3 meter integrating sphere testing, as temperature fluctuations can affect spectral characteristics and luminous flux measurements, particularly during extended tests or when evaluating high-power light sources. The constant-temperature design ensures consistent and reliable results.
• Low Stray Light Design
The LPCE-2 system integrates the 3 meter integrating sphere with the LMS-9000C spectroradiometer, which employs bandpass filter wheel calibration and improved NIST stray light correction techniques. These technologies reduce stray light to less than 0.015% at 600 nm and less than 0.03% at 435 nm. Low stray light levels are critical for maintaining measurement accuracy in 3 meter integrating sphere testing, especially when measuring low-luminous-flux sources or those with unique spectral distributions.
• Multifunctional Test Ports
The 3 meter integrating sphere features multiple test ports that can connect to fast photometric probes, spectroradiometers, and auxiliary light source interfaces. These ports enable simultaneous measurement of luminous flux, colorimetric parameters (e.g., chromaticity coordinates, correlated color temperature, and color rendering index), and flicker parameters. This multifunctional design positions the 3 meter integrating sphere as a core component of the LPCE-2 system’s comprehensive testing capabilities.
• Compliance with International Standards
The 3 meter integrating sphere produces test results that comply with international standards such as CIE-127, IES LM-79-19, LM-80, and EU ErP Regulation (EU) 2019/2020. This ensures that data obtained from 3 meter integrating sphere testing is globally recognized, supporting manufacturers in meeting certification requirements for international markets.

Specific Role of the 3 Meter Integrating Sphere in the LPCE-2 (LMS-9000) System

The 3 meter integrating sphere serves several critical functions within the LPCE-2 (LMS-9000) system, enabling precise and reliable measurements for a range of LED lighting parameters:

• Luminous Flux Measurement
Luminous flux, a key metric for assessing the light output of LED luminaires, is accurately measured using the 3 meter integrating sphere. Its large size and high-reflectivity coating allow it to capture the total light output from a light source, regardless of its directionality. The system records luminous flux data through photometric probes or spectroradiometer ports on the sphere’s wall, with the LMS-9000C spectroradiometer’s wavelength calibration ensuring measurement accuracy of ±0.5%. The 3 meter integrating sphere is particularly effective for testing high-power luminaires, where smaller spheres may struggle to provide accurate results.
• Colorimetric Parameter Testing
In combination with the LMS-9000C spectroradiometer, the 3 meter integrating sphere enables precise measurement of colorimetric parameters, including chromaticity coordinates, correlated color temperature (CCT), color rendering index (CRI), and spectral power distribution (SPD). The uniform light field created by the sphere eliminates the impact of light source directionality, making it ideal for testing large LED luminaires with complex light distributions during 3 meter integrating sphere testing.
• Luminous Efficacy and Electrical Parameter Measurement
The LPCE-2 system integrates the 3 meter integrating sphere with a digital electrical parameter meter (e.g., WT5000) to simultaneously measure luminous flux and electrical parameters such as voltage, current, and power factor. This enables the calculation of luminous efficacy (lm/W), a critical metric for evaluating the energy efficiency of LED luminaires. The 3 meter integrating sphere’s large size supports accurate testing of high-power luminaires, ensuring reliable luminous efficacy data.
• Flicker Testing Support
While flicker testing primarily relies on the LSRF-3 light source start-up, rise-time, and flicker test system, the 3 meter integrating sphere provides a stable light field environment that enhances flicker measurements. The uniform light distribution within the sphere facilitates accurate capture of luminous flux fluctuations, supporting the measurement of short-term flicker indicator (Pst) and stroboscopic visibility measure (SVM) in 3 meter integrating sphere testing.
• Lumen Maintenance Testing
For IES LM-80 testing, the 3 meter integrating sphere is used to evaluate the lumen maintenance of LED luminaires over extended periods. Its constant-temperature control and low stray light design ensure stable and reliable results during long-term aging tests, enabling accurate measurement of lumen maintenance rates and lifespan predictions.

Application Scenarios of the 3 Meter Integrating Sphere

The 3 meter integrating sphere in the LPCE-2 (LMS-9000) system is utilized across a wide range of applications in LED lighting testing, including:

• Large-Scale LED Luminaire Production
On production lines, the 3 meter integrating sphere is used to test the luminous flux and colorimetric parameters of high-power LED luminaires, such as streetlights, floodlights, and high-bay lights. Its large size allows for whole-luminaire testing, eliminating the need for disassembly and reassembly. This ensures compliance with standards like Energy Star V2.1 and EU ErP Regulation (EU) 2019/2020, enhancing product quality and market readiness.
• Lighting Engineering Projects
In large-scale lighting projects, such as stadium or airport illumination, the 3 meter integrating sphere verifies the optical performance of luminaires to ensure compliance with design specifications and safety standards. Its ability to test large luminaires accurately makes it an invaluable tool for project validation.
• Research and Development
Research institutions use the 3 meter integrating sphere to study the optical performance of novel LED light sources, analyzing the impact of different materials, driver designs, or optical configurations on luminous flux and efficacy. The sphere’s high precision and multifunctionality make it an ideal tool for laboratory-grade 3 meter integrating sphere testing.
• Third-Party Certification Testing
Third-party testing agencies employ the 3 meter integrating sphere in the LPCE-2 (LMS-9500C scientific-grade configuration) to conduct IES LM-79-19 and LM-80 certification tests. The resulting reports meet international standards, facilitating market access for LED products in regions like North America and Europe.

• Specialized Light Source Testing
The 3 meter integrating sphere is also used to test non-standard or complex light sources, such as horticultural grow lights or stage lighting fixtures. Its large size and uniform light field ensure comprehensive and accurate results in 3 meter integrating sphere testing for these specialized applications.

Impact of the 3 Meter Integrating Sphere on the LED Lighting Testing Industry

The 3 meter integrating sphere has significantly influenced the LED lighting testing industry, offering several key benefits:

• Enhanced Testing Precision and Efficiency
The large size and high-reflectivity coating of the 3 meter integrating sphere improve the accuracy of luminous flux and colorimetric measurements, reducing errors associated with spatial constraints in smaller spheres. The constant-temperature control and low stray light design further enhance result stability, streamlining testing processes and reducing cycle times.
• Promotion of Industry Standardization
By producing test results that comply with standards like CIE-127, IES LM-79-19, LM-80, and EU ErP Regulation (EU) 2019/2020, the 3 meter integrating sphere supports the standardization and globalization of LED lighting testing. This is critical for manufacturers seeking to meet diverse regulatory requirements and enhance product competitiveness.
• Support for High-Power Luminaire Testing
As high-power LED luminaires become more prevalent, the 3 meter integrating sphere addresses the limitations of smaller spheres, providing a reliable solution for testing large-scale lighting products. This capability is essential for ensuring the quality and performance of high-power luminaires.
• Facilitation of Technological Innovation
The precise data generated by the 3 meter integrating sphere provides a scientific foundation for advancing LED luminaire design, including innovations in optical systems, driver technologies, and materials. This supports the development of next-generation LED lighting solutions.

Conclusion

The 3 meter integrating sphere in the LISUN LPCE-2 (LMS-9000) system is an indispensable component for LED lighting testing, leveraging its large-scale design, high-reflectivity coating, constant-temperature control, and low stray light technology to deliver exceptional performance. It enables precise measurement of luminous flux, colorimetric parameters, luminous efficacy, and supports flicker and lumen maintenance testing, meeting the diverse needs of research, production, and certification. By enhancing testing accuracy, promoting industry standardization, and supporting high-power luminaire testing, the 3 meter integrating sphere provides robust technical support for the LED lighting industry. As lighting technology continues to evolve, the 3 meter integrating sphere will play an increasingly vital role in addressing complex testing challenges, improving product quality, and enhancing user experience in the global LED lighting market.

Tags：LPCE-2(LMS-9000)