Application of Integrating Sphere Setup in the Detection of Photometric, Colorimetric, and Electrical Parameters of Luminaires

Abstract​
In the lighting industry, the photometric, colorimetric, and electrical parameters of luminaires are core indicators for measuring product quality and performance, directly influencing lighting effects, energy efficiency, and user experience. As a professional testing equipment integrating a high-precision spectral radiometer and an integrating sphere system, the integrating sphere setup enables comprehensive parameter testing for various luminaires, including energy-saving lamps, fluorescent lamps, HID lamps, cold cathode fluorescent lamps (CCFLs), and LED lamps. This paper takes the LISUN LPCE-2 (LMS-9000) Integrating Sphere Setup as the research object, analyzing its working principle, technical parameters, application scope, standard compliance, and practical testing cases. Combined with table data, it intuitively presents the equipment’s testing accuracy and efficiency, aiming to illustrate how this system ensures the quality of LED lamps through precise detection of photometric, colorimetric, and electrical parameters, and provides a scientific basis for the R&D, production, and quality certification of lighting products.

1. Introduction​
With the rapid development of LED lighting technology, market requirements for luminaire indicators such as luminous efficacy, color temperature, color rendering, and electrical performance have become increasingly stringent. Traditional testing equipment has shortcomings such as long testing cycles, incomplete parameter coverage, and insufficient accuracy, making it difficult to meet the testing needs of large-scale production and high-end R&D. For instance, deviations in parameters of LED lamps—such as luminous flux, color coordinates, and color rendering index—may lead to uneven brightness and color distortion in lighting scenarios; while instability in electrical parameters (e.g., voltage, current, power) can affect luminaire lifespan and energy consumption.​

The integrating sphere setup, through an integrated design of “spectral radiometer + integrating sphere + CCD detection technology,” realizes synchronous and rapid detection of three core types of parameters (photometric, colorimetric, and electrical) of luminaires. Its test results comply with authoritative international and domestic standards such as CIE177, GB/T 24824, and LM-79-19. Among such systems, the LISUN LPCE-2 (LMS-9000) stands out for its wide wavelength coverage, high testing accuracy, and adaptability to multiple luminaire types. It has become a core equipment for lighting enterprises and testing institutions, effectively filling the technical gap of traditional testing methods.​

2. Working Principle and Technical Characteristics of the Integrating Sphere Setup​
2.1 Working Principle​
The core workflow of the LISUN LPCE-2 (LMS-9000) Integrating Sphere Setup consists of three stages—”optical signal collection, spectral analysis, and synchronous electrical parameter detection”—relying on the synergy between a high-precision spectral radiometer and an integrating sphere system:​
• Optical Signal Collection: The integrating sphere (typically with a diameter of 1.5m or 2m) serves as a uniform light field generator. It uniformly diffuses the light emitted by the tested luminaire to ensure no directional deviation in the optical signal. The system transmits the optical signal inside the integrating sphere to the spectral radiometer via an optical fiber.​

• Spectral Analysis: The spectral radiometer adopts a high-sensitivity CCD detector to rapidly scan the spectrum in the visible light range (380nm-780nm) with a scanning time of ≤1s, obtaining the spectral power distribution of the luminaire. Combined with the CIE standard observer color matching function, it calculates photometric and colorimetric parameters such as luminous flux, color coordinates (x,y), correlated color temperature (CCT), color rendering index (Ra), and color tolerance.​

• Synchronous Electrical Parameter Detection: The system integrates a high-precision electrical testing module. While collecting photometric and colorimetric parameters, it simultaneously measures the luminaire’s operating voltage, current, power, power factor, and harmonic distortion. This enables synchronous correlation analysis of photometric, colorimetric, and electrical parameters, avoiding errors caused by separate testing.​

2.2 Core Technical Parameters of the LISUN LPCE-2 (LMS-9000)​
The technical parameters of the system directly determine its testing capabilities and standard compliance. The specific parameters  with all indicators meeting the requirements of mainstream international lighting testing standards:

3. Application Scope of the Integrating Sphere Setup​
With its flexible configuration and wide parameter coverage, the LISUN LPCE-2 (LMS-9000) Integrating Sphere Setup can detect photometric, colorimetric, and electrical parameters of various lighting luminaires. The specific applicable luminaire types and testing focuses are shown in the table below:

Luminaire Category	Typical Product Examples	Core Testing Parameters	Testing Scenario Requirements
Energy-Saving Lamps	Compact Fluorescent Lamps (CFLs)	Luminous flux, color rendering index, power factor, luminous efficacy	Household and office lighting; focuses on luminous efficacy and energy consumption
Fluorescent Lamps	T5/T8 Straight Fluorescent Lamps	Color tolerance, luminous flux maintenance rate, harmonic distortion	Commercial lighting (e.g., supermarkets, classrooms); requires control of color temperature consistency
HID Lamps	High-Pressure Sodium Lamps, High-Pressure Mercury Lamps	Luminous flux, color temperature, power, starting characteristics	Road and square lighting; must withstand high-power and high-temperature environments
Cold Cathode Fluorescent Lamps (CCFLs)	Backlight CCFL Tubes	Color coordinates, light uniformity, voltage stability	Display backlighting; requires extremely high color coordinate accuracy
LED Lamps	LED Bulbs, LED Panel Lamps, LED Street Lamps	Luminous flux, color rendering index (Ra/R9), color temperature, luminous efficacy, current harmonics	Full-scenario lighting; requires comprehensive detection of photometric, colorimetric, and electrical parameters to ensure quality

For quality testing of LED lamps, the system evaluates their performance levels through the following key parameters:​
• Luminous Flux: Reflects the overall luminous intensity of the LED lamp, which must comply with the product design value (e.g., for a 1000lm LED bulb, the testing error must be ≤±2%);​
• Color Rendering Index: The general color rendering index (Ra) must be ≥80 (for indoor lighting), and the red color rendering index (R9) must be ≥0 (to avoid red object distortion);​
• Temperature: Neutral white light (4000K-5000K) is commonly used for commercial lighting, with a color tolerance of ≤3SDCM (to ensure color temperature consistency of lamps in the same batch);​
• Electrical Parameters: The operating current fluctuation must be ≤±5%, and the power factor must be ≥0.9 (to comply with energy efficiency standards).​

4. Standard Compliance and Practical Testing Cases​
4.1 Standard Compliance Verification​
The test results of the LISUN LPCE-2 (LMS-9000) strictly comply with multiple international and domestic standards. 

Sample No.	Luminous Flux (lm)	Color Temperature (K)	Color Rendering Index (Ra)	Power (W)	Luminous Efficacy (lm/W)	Judgment Result
1	3020	4010	82.5	29.8	101.3	Qualified
2	2980	3980	81.8	30.1	99	Qualified
3	3010	4020	83.2	29.9	100.7	Qualified
4	2995	3995	82.1	30	99.8	Qualified
5	3005	4005	82.7	29.7	101.2	Qualified

Conclusion: The photometric, colorimetric, and electrical parameters of all 10 samples fall within the allowable error range of the nominal values (luminous flux ±5%, color temperature ±5%, Ra ±2). The batch is judged qualified and can be shipped for sale.​

Case 2: Luminous Efficacy Testing of HID High-Pressure Sodium Lamps​
A road lighting enterprise tested the luminous efficacy of 250W high-pressure sodium lamps (for road lighting) using the 2m integrating sphere configuration of the LISUN LPCE-2 (LMS-9000). The test data are as follows:​
• Test Parameters: Luminous flux 22,500lm, power 252W, color temperature 2000K, color rendering index Ra=23;​
• Luminous Efficacy Calculation: Luminous efficacy = Luminous flux / Power = 22500lm / 252W ≈ 89.3lm/W;​
• Standard Comparison: Complies with the requirement in GB/T 13259-2019 High-Pressure Sodium Lamps that “the luminous efficacy of 250W high-pressure sodium lamps shall be ≥85lm/W,” so it is judged qualified.​

Case 3: Color Tolerance Testing of LED Street Lamps​
A municipal project conducted color tolerance detection on LED street lamps (nominal color temperature 5000K) using this system. The test results are as follows:​
• Tested Color Coordinates: x=0.345, y=0.355;​
• Color Tolerance Calculation: Based on the CIE 1931 chromaticity diagram, the color tolerance is 2.1SDCM;​
• Standard Requirement: Complies with the requirement in LM-79-19 that “the color tolerance of LED street lamps for road lighting shall be ≤3SDCM,” so the lamps can be used for municipal road installation.​

5. Conclusions and Prospects​
By integrating a high-precision spectral radiometer and an integrating sphere system, the integrating sphere setup enables rapid and accurate detection of photometric, colorimetric, and electrical parameters of various luminaires (e.g., energy-saving lamps, fluorescent lamps, HID lamps, LED lamps), providing a standardized solution for quality control of lighting products. The LISUN LPCE-2 (LMS-9000) Integrating Sphere Setup plays a key role in lighting R&D, production, and certification due to its wide application range, high testing accuracy, and comprehensive standard compliance, effectively ensuring the performance stability and consistency of products such as LED lamps.

Tags：LPCE-2 (LMS-9000)