lux meter test in Multi-parameter Testing of Light Source Optical Performance: Application and Technical Analysis

Abstract
As lighting technology advances toward intelligence and specialization, the accurate testing of light source optical performance parameters has become a key link in evaluating lighting quality, ensuring visual health, and promoting industry standardization. This paper takes the LISUN LMS-6000 series lux meter test as the research object, systematically expounding its technical advantages and application scenarios in the testing of core optical performance parameters such as illuminance, chromaticity coordinates, correlated color temperature (CCT), and color rendering index (CRI). By analyzing the hardware architecture, parameter testing principles, and compliance with international standards of this series of instruments, and verifying its performance accuracy with actual test data tables, it provides reliable technical references for fields such as lighting engineering testing, lamp research and development, and quality control, highlighting the irreplaceability of lux meter test in on-site rapid detection scenarios.

1. Introduction
In the modern lighting system, the optical performance of light sources not only directly affects visual comfort and work efficiency, but also is closely related to light pollution control, energy conservation, and application effects in special fields (such as plant lighting and medical lighting). Although traditional desktop spectrometers can achieve high-precision testing, they are limited by their size and portability, making it difficult to meet the needs of on-site rapid detection. The lux meter test, with its core advantages of “miniaturization, high precision, and real-time performance”, has become an important tool in the field of lighting detection.

The LMS-6000 series lux meter test developed by LISUN adopts a long-focal-length cross-asymmetric CT spectroscopic system, covering a wavelength range of 380-780 nm (some models extended to 200-950 nm). It can complete the testing of more than 20 optical performance parameters such as illuminance, chromaticity coordinates, correlated color temperature (CCT), and color rendering index (CRI) at one time, and is widely used in scenarios such as LED lamp detection, urban lighting operation and maintenance, and laboratory research and development. This paper will comprehensively analyze the technical value of this series of lux meter test from four dimensions: instrument technical principle, core parameter testing capability, practical application cases, and performance verification.

2. Technical Architecture and Testing Principle of LISUN LMS-6000 lux meter test
2.1 Core Hardware Architecture
The core performance of the LISUN LMS-6000 series lux meter test stems from its advanced hardware design, which mainly includes three modules:
• Spectroscopic System: It adopts long-focal-length cross-asymmetric CT spectroscopy technology, which can effectively reduce stray light interference (stray light < 0.015% at 600 nm and < 0.03% at 435 nm), ensuring a wavelength resolution of ±0.2 nm and a wavelength accuracy of ±0.5 nm, providing a stable optical foundation for multi-parameter testing.
• Detection and Data Processing Module: Equipped with a high-sensitivity CCD detector, combined with a 4000 mAh rechargeable lithium battery (with a continuous working time of 20 hours), it can realize flexible integration time adjustment from 0.1 ms to 5 s, adapting to different light intensity scenarios (illuminance testing range: 0.1-500,000 lx).
• Human-Computer Interaction and Storage Module: It is equipped with a 5-inch high-definition IPS capacitive touch screen (resolution: 480*854), supports 8 GB of storage space (which can store 5,000-100,000 test reports), and is compatible with computer communication of Win7-Win11 systems, facilitating data export and secondary analysis.

2.2 Testing Principle of Core Parameters
The multi-parameter testing capability of the lux meter test is based on the principle of “spectral radiometry”. By measuring the spectral power distribution (SPD) of the light source and combining with the standard observer spectral tristimulus values recommended by the International Commission on Illumination (CIE), various optical performance parameters are calculated:
• Illuminance (lx) and Luminous Flux – Related Parameters (E(Fc), Ee (W/m²)): Illuminance is calculated by integrating the spectral radiant flux received by the detector. 1 lx is equal to 1 lm of luminous flux evenly distributed over an area of 1 m²; E(Fc) is the imperial illuminance unit (1 Fc ≈ 10.764 lx), and Ee is the irradiance, reflecting the radiant power received per unit area.
• Chromaticity Coordinates and Correlated Color Temperature (CCT): Chromaticity coordinates (x, y) are calculated based on the CIE 1931 standard chromaticity system through the integration of spectral power distribution and tristimulus values; CCT is determined by the degree of deviation between the chromaticity coordinates and the blackbody locus. The CCT testing range of the LMS-6000 series covers 1500 K-100,000 K with an accuracy of ±0.6%, which can accurately distinguish different light source types such as cool white light and warm white light.
• Color Rendering Index (CRI) and TM-30 Parameters: CRI (Ra) is calculated by comparing the color rendering effects of the light source and the standard blackbody/daylight on 8 standard color chips (range: 0-100, accuracy: ±(0.3% rd ± 0.3)); TM-30 parameters (Rg gamut index, Rf fidelity index) are based on the CIE TM-30-15 standard, evaluating the ability of the light source to restore the color of real objects through 100 test color chips, which are key indicators for high-end lighting scenarios (such as museums and operating rooms).
• Color Tolerance and Color Difference Parameters: Color tolerance reflects the deviation between the chromaticity coordinates of the light source and the target coordinates (in SDCM units). The LMS-6000 can visually display the deviation degree through the color tolerance diagram; total color difference (ΔE), brightness difference, red-green degree (a*), and yellow-blue degree (b*) are based on the CIE LAB color space, which are used to evaluate the color consistency of different light sources or different batches of the same light source.

3. Core Parameter Testing Capability and Application Scenarios of LISUN LMS-6000 lux meter test
3.1 Parameter Testing Coverage Capability of the Full-Series Models
The LISUN LMS-6000 series lux meter test includes 12 subdivided models, with optimized parameter testing ranges for different application needs. Among them, the basic model LMS-6000 already covers more than 20 core parameters, and some models have expanded special functions (such as UV testing, stroboscopic testing, and plant lighting parameters). The following table shows the comparison of parameter testing capabilities of the core models in this series:

3.2 Analysis of Typical Application Scenarios
Urban Lighting Operation and Maintenance (in accordance with CJJ/T261-2017 Standard)Public lighting such as urban roads and squares needs to meet requirements such as illuminance uniformity and power density. Using the LMS-6000 lux meter test, the average illuminance of motor vehicle lanes (10-30 lx) and the uniformity of sidewalks (≥0.3) can be quickly tested on-site, and the CCT can be recorded simultaneously (to avoid visual fatigue caused by the deviation of light source color temperature). For example, during the detection of LED street lamps on a main road in a municipal project, some lamps were found to have CCT deviating from the design value (designed 4000 K, actually measured 3500 K) through the LMS-6000, and the batches were replaced in time to ensure lighting quality.

Factory Quality Control of LED LampsLamp manufacturers can use the LMS-6000 to conduct sampling tests on CRI and color tolerance for each batch of products. For example, a certain LED bulb manufacturer requires CRI ≥ 80 and color tolerance ≤ 3 SDCM. Through on-site testing with the lux meter test, unqualified products (such as CRI = 75, color tolerance = 5 SDCM) can be quickly screened out to prevent them from entering the market. In addition, the stroboscopic testing function of the LMS-6000F can detect the modulation depth of lamps (required ≤ 30%), preventing visual discomfort caused by stroboscopic.

Special Optimization of Plant LightingPlant lighting requires precise control of parameters such as PAR (400-700 nm) and PPFD (the suitable PPFD for lettuce growth is 200-400 μmol/m²·s). The LMS-6000P lux meter test can test PPFD and red-blue radiation ratio (optimal 1:1.2) in real time, helping growers adjust the height and power of lamps to improve crop yield. A certain plant factory optimized the lighting parameters in the tomato planting area through this instrument, increasing the yield by 15%.

4. Performance Verification and Standard Compliance of LISUN LMS-6000 lux meter test
4.1 Accuracy Verification Data
To verify the testing accuracy of the LMS-6000 lux meter test, a standard light source (CCT = 5000 K, CRI = 95) was selected for repeated testing, and the results are shown in the following table:

It can be seen from the data that the measured deviation of each parameter is less than the nominal accuracy of the instrument, which proves that the LMS-6000 lux meter test has stable high-precision testing capability.

4.2 Standard Compliance
The LISUN LMS-6000 series strictly complies with international and domestic authoritative standards to ensure the universality and recognition of test results:
• Color rendering testing: Complies with CIE-13.3 “Methods of Measurement and Specification of the Color Rendering Properties of Light Sources” and CIE-177 “Color Rendering of White LED Light Sources”;
• Color temperature and chromaticity coordinates: Complies with the CIE 1931 chromaticity system and CIE 1960 UCS system;
• Blue light hazard: Complies with GB/T20145 “Photobiological Safety of Lamps and Lamp Systems” and CIE S009/E:2002;
• Stroboscopic testing: Complies with IEEE “Recommended Practices for Modulating Current in High-Brightness LEDs for Mitigating Health Risks to Viewers”.

LMS-6000 Portable CCD Spectroradiometer

5. Conclusions and Prospects
The LISUN LMS-6000 series lux meter test solves the pain point that traditional testing equipment “is difficult to balance portability and accuracy” through advanced spectroscopic technology, high-precision detection modules, and comprehensive parameter testing capabilities, providing a reliable on-site rapid detection solution for the lighting industry. Its high-precision performance in the testing of core parameters such as illuminance, CCT, and CRI, as well as the coverage of special parameters such as TM-30, blue light hazard, and plant lighting, enable it to meet the diverse needs from general lighting to special fields.