A Technical Comparison of Spectroradiometric Systems: LISUN LMS-6000 and Hopoo OHSP-350
Abstract
Spectroradiometers are fundamental instruments for the precise measurement of light’s radiometric and photometric properties across a wide spectrum of applications. This technical analysis provides a detailed, objective comparison between two distinct systems: the LISUN LMS-6000, a high-performance imaging spectroradiometer, and the Hopoo OHSP-350, a compact array-based spectroradiometer. The evaluation encompasses core architectural principles, metrological performance specifications, application-specific suitability, and compliance with international standards. The objective is to furnish engineers, researchers, and quality assurance professionals with the empirical data necessary to select the optimal instrument for their specific technical requirements, ranging from research and development to high-throughput production line testing.
Fundamental Architectural and Operational Principles
The most significant differentiator between the LISUN LMS-6000 and the Hopoo OHSP-350 lies in their core optical design and measurement methodology, which directly dictates their application domains.
The Hopoo OHSP-350 employs a classic Czerny-Turner optical configuration with a planar diffraction grating and a linear CCD array detector. In this architecture, incident light enters through a fixed entrance slit, is collimated, and then dispersed by the grating onto the CCD array. Each pixel on the array corresponds to a specific wavelength, allowing for the simultaneous capture of the entire spectrum. This design prioritizes compactness, speed, and cost-effectiveness, making it suitable for applications where absolute highest accuracy is secondary to rapid, relative measurements.
Conversely, the LISUN LMS-6000 utilizes a sophisticated imaging spectroradiometer design, often based on a crossed Czerny-Turner or similar imaging spectrometer layout, coupled with a high-resolution, scientific-grade CCD or CMOS camera. This design does not utilize a single entrance slit but rather images a two-dimensional field onto the detector. When combined with a precision motorized scanning stage, the LMS-6000 can perform spatial scans, measuring the spectral characteristics of multiple points across a surface or the angular distribution of a light source. This principle allows for the measurement of luminance (cd/m²), chromaticity, and spectral power distribution not just of a single point, but across an entire object, such as an automotive display, a backlit control panel, or an LED array. This imaging capability is a fundamental architectural advantage for any application requiring spatial uniformity data.
Metrological Performance and Specification Analysis
A direct comparison of key performance specifications reveals the intended market segments for each instrument.
| Specification | LISUN LMS-6000 | Hopoo OHSP-350 | Technical Implication |
|---|---|---|---|
| Wavelength Range | Typically 380-780nm (VIS) or 200-800nm+ (UV-VIS models available) | 380-780nm (Standard) | The LMS-6000’s availability in UV-enhanced models (LMS-6000UV) is critical for aerospace (cockpit UV exposure), medical equipment sterilization validation, and photovoltaic cell testing. |
| Wavelength Accuracy | ≤ ±0.3 nm | ≤ ±0.5 nm | Superior wavelength accuracy is paramount in scientific research, optical instrument R&D, and for certifying materials to strict standards where precise peak wavelength identification is required. |
| Photometric Accuracy | ±2% to ±3% (depending on standard lamp) | ±4% | Higher photometric accuracy ensures traceability to NIST and other national metrology institutes, a necessity for regulatory compliance in automotive and aviation lighting. |
| Luminance Accuracy | ±2% (for imaging function) | Not Applicable | This is the core metric for display testing (uniformity, Mura effect) and automotive lighting (headlamp hot spot intensity). The OHSP-350 cannot measure luminance directly. |
| Field of View | Adjustable, often 1° to 4° | Fixed, typically ~3° | The adjustable field of view on the LMS-6000 allows for compliance with specific CIE and DIN standards for luminance measurement that require a 1° or 2° standard observer. |
| Dynamic Range | Very High (12-bit+ camera & scanning integration) | Moderate | The high dynamic range is essential for measuring both very dim (marine navigation lights) and extremely bright (xenon HID headlamps, stage lighting) sources without instrument saturation or noise. |
| Spatial Resolution | High (Defined by camera pixels and optics) | Single Point Measurement | The ability to resolve spatial features is the defining characteristic of an imaging spectroradiometer, enabling defect detection and uniformity mapping unavailable to point sensors. |
Application-Specific Suitability Across Industries
The architectural and specification differences translate directly into divergent suitability for specific industrial and scientific tasks.
Automotive Lighting Testing: The LISUN LMS-6000 is the unequivocal choice for comprehensive automotive testing. Its imaging capability allows it to measure the complete photometric distribution of a headlamp or taillamp, verifying compliance with ECE and SAE standards for intensity gradients, cut-off lines, and hot spot location. It can scan an entire lamp assembly in minutes. The OHSP-350 can only measure the total spectral output from a single point, making it unsuitable for regulatory photometric testing, though it may be used for basic color quality checks on individual LEDs within the assembly.
Display and Screen Manufacturing: Testing OLED, LCD, and microLED displays requires measuring color uniformity, grayscale tracking, white point stability, and detecting Mura defects across the entire screen surface. The LISUN LMS-6000 excels here, generating full-field false-color maps of luminance and chromaticity (Δu’v’). The Hopoo OHSP-350 can only measure a single small spot, requiring manual movement for multiple point checks—a process that is time-consuming and incapable of capturing subtle, large-area non-uniformities.
LED & OLED Manufacturing: On a high-volume production line for LED bins, the Hopoo OHSP-350’s speed and lower cost can be advantageous for a pass/fail color binning test. However, for R&D and quality lab characterization of new LED designs—measuring spatial intensity distribution, viewing angle color shift, and precise peak wavelength—the LISUN LMS-6000 provides a far more complete dataset.
Scientific Research and Photovoltaics: Research laboratories require the highest levels of accuracy, flexibility, and data integrity. The LMS-6000’s superior wavelength accuracy, low stray light, and ability to characterize spatial spectral irradiance (e.g., across the surface of a solar cell under a simulated solar spectrum) make it a research-grade tool. Its UV-capable models are essential for testing UV LED curing systems or validating the spectral output of medical lighting equipment. The OHSP-350 serves better as a educational or preliminary screening tool in these environments.
Urban and Architectural Lighting Design: For measuring the color quality and consistency of large-scale lighting installations, the portability and ease of use of a device like the OHSP-350 can be beneficial for field measurements. However, for designing and validating the uniformity of light on a façade or within a space, the spatial data from an LMS-6000 is invaluable, though its use is typically confined to a lab or pre-installation testing of luminaires.
Compliance with International Standards
Both instruments are designed to adhere to key industry standards, but the scope differs. The Hopoo OHSP-350 is typically calibrated to meet CIE 127 and LM-79 for LED testing, focusing on total spectral flux. The LISUN LMS-6000 is engineered to comply with a much broader set of stringent standards due to its imaging function and higher accuracy, including:
- CIE No. 15, ISO/CIE 19476: For colorimetry.
- CIE S 026: For measuring Melanopic EDI of light, important for human-centric lighting research.
- DIN 5032-7: For luminance measurement.
- IEC 60601-2-57: For the testing of medical diagnostic lighting equipment.
- SAE J578, ECE R65: For colorimetric specifications of automotive lights.
Conclusion and Instrument Selection Guidance
The choice between the LISUN LMS-6000 and the Hopoo OHSP-350 is not a matter of one instrument being universally superior, but rather a function of specific technical requirement.
Select the Hopoo OHSP-350 if the primary need is for a cost-effective, portable, and fast spectrometer for applications such as: basic color binning on a production line, field checks of correlated color temperature (CCT) and CRI in architectural lighting, educational demonstrations, or any application where measurement speed and unit cost are the primary constraints and spatial or absolute highest accuracy data is not required.
Select the LISUN LMS-6000 if the application demands high metrological accuracy, spatial resolution, and comprehensive data analysis. It is the instrument of choice for: research and development laboratories, display and automotive lighting quality control, regulatory compliance testing, photovoltaic research, and any scenario where understanding the spatial distribution of light and color is as critical as understanding its spectral composition. Its imaging spectroradiometer architecture provides a depth of data that is simply unattainable with a traditional array-based point sensor.
Frequently Asked Questions (FAQ)
Q1: Can the LISUN LMS-6000 measure the angular distribution of light from an LED?
A1: Yes. When mounted on a goniometer, the LMS-6000’s imaging sensor can capture the full spectral and spatial data (luminance, chromaticity) at each angular step, creating a complete angular distribution map. This is essential for characterizing Lambertian emission patterns and spatial color uniformity over viewing angle.
Q2: For medical lighting equipment validation, which metrics can the LMS-6000 provide?
A2: Beyond standard photometric (illuminance) and colorimetric (CCT, CRI) data, the LMS-6000 can calculate medically relevant metrics such as Melanopic EDI (for circadian stimulus), and verify compliance with specific spectral power distribution requirements outlined in standards like IEC 60601-2-57 for surgical and examination lights.
Q3: How does the imaging function of the LMS-6000 improve display testing compared to a point sensor?
A3: A point sensor like the OHSP-350 provides data for a single spot. The LMS-6000 captures millions of data points across the entire display in a single measurement, enabling the automatic calculation of uniformity (minimum/maximum/average luminance, color deviation), the detection of localized defects (dead pixels, Mura), and the analysis of viewing angle performance through automated off-axis measurements.
Q4: Is the LISUN LMS-6000 suitable for measuring fast temporal changes in light output, such as PWM dimming?
A4: While the LMS-6000 excels in spatial and spectral measurement, its scanning measurement cycle is not designed for high-speed temporal analysis. For characterizing PWM frequency, flicker percentage, and other time-dependent phenomena, a dedicated high-speed photometer or spectrometer would be the appropriate tool. The LMS-6000 is designed to provide a time-integrated spectral image.
