Abstract
The Spectroradiometer Integrating Sphere system has emerged as a critical tool in the photometric, colorimetric, and electrical characterization of modern lighting products, including energy-saving lamps, fluorescent lamps, HID lamps (such as high-pressure sodium and mercury lamps), cold-cathode fluorescent lamps, and LED lamps. This paper focuses on the LISUN LPCE-2 (LMS-9000C) High Precision Spectroradiometer Integrating Sphere System, exploring its technical specifications, testing capabilities, compliance with international standards, and practical applications. By integrating detailed parameter analyses and comparative tables, this study demonstrates how the system ensures precise quality assessment of lighting products, particularly for LEDs, by evaluating their optical, chromatic, and electrical properties.
1. Introduction: The Significance of Spectroradiometer Integrating Sphere in Lighting Testing
The advancement of lighting technology has led to a diverse range of light sources, each requiring rigorous testing to ensure performance, energy efficiency, and quality. The Spectroradiometer Integrating Sphere system combines two key components: a spectroradiometer, which measures the spectral distribution of light, and an integrating sphere, which uniformly collects and scatters light to enable accurate total flux measurement. This combination is indispensable for characterizing light sources across various types, from traditional HID lamps to cutting-edge LED products.
For LED lighting, in particular, quality assessment hinges on comprehensive testing of photometric parameters (e.g., luminous flux, efficiency), colorimetric attributes (e.g., chromaticity, color rendering index), and electrical properties (e.g., voltage, power factor). The LISUN LPCE-2 (LMS-9000C) system exemplifies the integration of these functionalities, offering high-precision measurements compliant with international standards such as CIE 177, CIE 84, IES LM-79-19, and EU regulations. Its design caters to both middle-small manufacturers and general test labs, ensuring reliable data for product development, quality control, and certification.
LPCE-2(LMS-9000)High Precision Spectroradiometer Integrated Sphere System
The LPCE-2 (LMS-9000C) system comprises a High Precision CCD Spectroradiometer (LMS-9000C), optical fiber, digital power meter, DC/AC power sources, integrating spheres (IS-1.5MA and IS-0.3M), standard light sources, and a 19-inch cabinet. The core innovation lies in its a-molding integrating sphere, which features a more spherical structure than traditional designs, minimizing measurement errors and enhancing accuracy.
The spectroradiometer employs a high-sensitivity CCD detector, enabling spectral measurements from 350nm to 800nm (with variants extending to UV-VIS or NIR ranges). The system connects to a PC via USB, supported by Microsoft-certified drivers for Windows 7-11, and integrates software with self-absorption coefficient correction and auxiliary lamp devices for comprehensive testing.
| Parameter | LMS-9000C | LMS-9000C UV-VIS | LMS-9000C VIS-NIR |
|---|---|---|---|
| Wavelength Range | 350-800nm | 200-800nm | 350-1050nm |
| Spectral Wavelength Accuracy | ±0.3nm | ±0.3nm | ±0.3nm |
| Wavelength Reproducibility | ±0.1nm | ±0.1nm | ±0.1nm |
| Chromaticity Coordinate Accuracy (Δx, Δy) | ±0.002 (under Standard A Lamp) | ±0.002 | ±0.002 |
| Correlated Color Temperature (CCT) | 1,500K-100,000K | 1,500K-100,000K | 1,500K-100,000K |
| CCT Accuracy | ±0.3% | ±0.3% | ±0.3% |
| Color Rendering Index (CRI) Range | 0-100.0 | 0-100.0 | 0-100.0 |
| CRI Accuracy | ±(0.3%rd±0.3) | ±(0.3%rd±0.3) | ±(0.3%rd±0.3) |
| Luminous Flux Range | 0.01-200,000 lm | 0.01-200,000 lm | 0.01-200,000 lm |
| Photometric Linear Accuracy | ±0.5% | ±0.5% | ±0.5% |
| Stray Light (600nm/435nm) | <0.015%/<0.03% | <0.015%/<0.03% | <0.015%/<0.03% |
| Integration Time | 0.1-10,000 ms | 0.1-10,000 ms | 0.1-10,000 ms |
The Spectroradiometer Integrating Sphere system quantifies key photometric parameters essential for evaluating lighting efficiency and performance:
• Luminous Flux: Measured from 0.01 to 200,000 lm with ±0.5% accuracy, suitable for small LEDs to high-power HID lamps.
• Luminous Efficiency: Calculates lumens per watt (lm/W), a critical metric for energy-saving lamps and LEDs.
• Radiant Power: Measures the total optical energy emitted, vital for HID lamps and plant growth lights.
• Pupil Flux & Cirtopic Flux: Specialized measurements for human visual response and circadian rhythm impacts, increasingly relevant for modern lighting design.
For example, when testing LED panels, the system can simultaneously measure total flux and efficiency, ensuring compliance with energy efficiency standards like EU 2019/2015. For HID lamps, radiant power measurement helps assess heat dissipation and optical output stability.
Color characterization is central to lighting quality, especially for LEDs and fluorescent lamps:
• Chromaticity Coordinates (x, y): Measured with ±0.002 accuracy under Standard A Lamp, ensuring precise color point determination.
• Correlated Color Temperature (CCT): Ranging from 1,500K (warm white) to 100,000K (cool white), suitable for diverse lighting applications from residential to commercial.
• Color Rendering Index (CRI) & TM-30: Evaluates how accurately a light source reproduces colors, with CRI accuracy of ±(0.3%rd±0.3) and support for advanced metrics like Rf (fidelity) and Rg (gamut) in TM-30.
• Peak Wavelength & Half Bandwidth: Critical for monochromatic LEDs (e.g., red, blue) used in displays or plant lighting.
For fluorescent lamps, the system assesses color consistency and aging effects, while for cold-cathode lamps, it ensures chromatic stability across operating temperatures.
The system integrates precise electrical measurements to evaluate power consumption and safety:
• Voltage, Current, Power: Measures DC/AC parameters with high-precision power meters (e.g., LS2050B/C), essential for LED drivers and HID ballast analysis.
• Power Factor (PF) & Displacement Factor: Evaluates electrical efficiency, particularly important for grid-connected lighting systems.
• Harmonic Analysis (Optional): Complies with standards like IEC 61000-3-2, ensuring low harmonic distortion in electronic ballasts and LED drivers.
A unique strength of the LPCE-2 system is its capability to perform long-term aging tests for LEDs, monitoring:
• Flux degradation over time (Flux VS Time)
• CCT shift (CCT VS Time)
• CRI variation (CRI VS Time)
• Power and efficiency changes (Power VS Time, Flux Efficiency VS Time)
This data is crucial for predicting LED lifespan and lumen maintenance, supporting LM-80 compliance and enabling manufacturers to provide reliable lifetime warranties.
Traditional energy-saving lamps (e.g., compact fluorescent lamps, CFLs) and fluorescent tubes require comprehensive testing for:
• Luminous flux and efficiency to ensure energy-saving claims align with reality.
• Color stability, as fluorescent phosphors may degrade over time, affecting CCT and CRI.
• Electrical safety parameters, such as power factor and harmonic content, to meet grid requirements.
The Spectroradiometer Integrating Sphere system’s high-resolution spectral scanning (0.1nm steps) captures subtle changes in phosphor emission, enabling early detection of degradation mechanisms.
HID lamps pose unique testing challenges due to their high power and complex spectral emissions:
Radiant Power Measurement: Critical for HID lamps, as a significant portion of energy is emitted as heat rather than visible light. The system’s integrating sphere efficiently collects total radiant energy, including infrared components.
• Spectral Stability: HID lamps may exhibit spectral shifts during warm-up, which the system monitors with high temporal resolution (integration time down to 0.1ms).
• Lumen Maintenance: Similar to LEDs, HID lamps undergo lumen depreciation, and the system’s aging test capabilities support long-term performance evaluation.
CCFLs, commonly used in backlighting, require precise color and flux uniformity testing:
• Chromaticity Consistency: The system ensures batch-to-batch color uniformity, vital for display applications.
• Low-Temperature Performance: CCFLs may operate at low temperatures, and the system’s temperature measurement capabilities (inside/outside the integrating sphere) enable environment-specific testing.
LED testing with the LPCE-2 system covers:
• Single LEDs: Spectral characterization, forward voltage, and luminous intensity.
• LED Modules & Fixtures: Total flux, efficiency, and color mixing evaluation for multi-chip arrays.
• Specialized LEDs: Plant growth lamps (measuring PAR/PPF), UV-LEDs (with UV-VIS spectroradiometer variants), and infrared LEDs (with VIS-NIR models).
The system’s flexibility allows testing across LED product types, from consumer lighting to industrial and medical applications.
5. Compliance with International Standards
The LPCE-2 (LMS-9000C) system is designed to meet rigorous international standards, ensuring test results are globally 认可的 (recognized):
• CIE 177: Evaluates color rendering of white LED light sources.
• CIE 84: Specifies methods for luminous flux measurement.
• CIE-13.3: Defines color rendering property measurement for all light sources.
• IES LM-79-19: Establishes optical and electrical measurement protocols for SSL products.
• IES LM-80-08: Guides lumen maintenance testing for LED light sources.
• ANSI-C78.377: Sets chromaticity specifications for solid-state lighting products.
• EU 2019/2015: Mandates energy efficiency requirements for lighting products.
Compliance with these standards ensures that test data is acceptable for certification bodies, enabling manufacturers to enter global markets seamlessly.
6. Comparative Analysis: LMS-9000C vs. LMS-9500C Scientific Grade System
For reference, the table below compares the LPCE-2 (LMS-9000C) with its scientific-grade counterpart, the LPCE-2 (LMS-9500C), highlighting enhancements for advanced testing labs:
| Parameter | LMS-9000C (High Precision) | LMS-9500C (Scientific Grade) |
|---|---|---|
| Detector | Standard CCD | Hamamatsu TE-cooled (-10°C ±0.05°C), back-thinned |
| Spectral Wavelength Accuracy | ±0.3nm | ±0.2nm |
| Chromaticity Coordinate Accuracy | ±0.002 | ±0.0015 |
| CCT Accuracy | ±0.3% | ±0.2% |
| Photometric Linear Accuracy | ±0.5% | ±0.2% |
| Integration Time Range | 0.1-10,000 ms | 0.1 ms-60 s (extended for low-light scenarios) |
| Typical Application | Middle-small manufacturers, general labs | Large manufacturers, third-party test labs |
The LMS-9500C’s enhanced precision caters to research institutions and high-volume production lines requiring ultra-accurate measurements, while the LMS-9000C balances cost and performance for broader industrial use.
7. Practical Case Study: LED Lumen Maintenance Testing per IES LM-80
Using the LPCE-2 (LMS-9000C) system, a typical LM-80 compliance test involves:
• Sample Preparation: Mounting LED modules in the integrating sphere with controlled temperature (via optional IS-1.5MT Constant Temperature Sphere and TMP-8 Tester).
• Baseline Measurements: Recording initial flux, CCT, CRI, and electrical parameters.
• Aging Protocol: Operating LEDs at specified drive currents and temperatures for 1,000 to 10,000 hours.
• Periodic Testing: Measuring parameters every 1,000 hours to plot degradation curves.
• Data Analysis: Exporting LM-79-compliant reports in PDF/Excel, including flux maintenance trends and statistical analysis.
This process enables manufacturers to predict LED lifespan (e.g., L70, the time when flux drops to 70% of initial value) and ensure product reliability.
8. After-Sales Support and System Reliability
LISUN’s LPCE-2 systems, having been in the market for over a decade, are supported by a comprehensive after-sales framework:
• FAQ Databases: Summarizing common issues and solutions for self-troubleshooting.
• Technical Support: Remote assistance and on-site service from certified engineers.
• Calibration Services: Regular recalibration to maintain measurement accuracy, traceable to national standards.
• Software Updates: Periodic updates to incorporate new standards and functionality.
The system’s robust design, with temperature-stabilized detectors and high-quality optical components, ensures long-term reliability even in demanding production environments.
9. Conclusion: The Indispensable Role of Spectroradiometer Integrating Sphere in Modern Lighting Testing
The Spectroradiometer Integrating Sphere system, exemplified by the LISUN LPCE-2 (LMS-9000C), has become the gold standard for characterizing lighting products across the spectrum—from traditional HID lamps to cutting-edge LED solutions. Its ability to integrate photometric, colorimetric, and electrical measurements within a single platform, combined with compliance to international standards, makes it an essential tool for quality control, research and development, and certification.
As the lighting industry continues to evolve toward energy efficiency, smart controls, and human-centric lighting, the precision and versatility of such systems will only grow in importance. The LPCE-2 system’s adaptability to diverse light sources and testing requirements positions it as a cornerstone of modern lighting innovation, enabling manufacturers to deliver products that meet both technical specifications and consumer expectations.
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