Labsphere LMS series light measurement integrating spheres are available in six sizes from 0.25 to 3.0m diameter, for testing the total luminous flux and colour performance of any size or power of light source, from a single LED or lamp right up to the largest luminaires or street light fittings. The LMS interior access sphere design conforms to both IESNA LM-79 and EN 13032-4 standards, and the Spectraflect 98% sphere coating gives superior radiance uniformity, measurement accuracy and repeatability. Both 2pi directional and 4pi total hemispherical flux measurements are supported. Please note that LMS integrating spheres are available as part of complete Labsphere Illumia spectroradiometer systems.
Labsphere LMS Series Light Measurement Integrating Spheres
Labsphere LMS series light measurement integrating spheres are available in six sizes from 0.25 to 3.0m diameter, for testing the total luminous flux and colour performance of any size or power of light source, from a single LED or lamp right up to the largest luminaires or street light fittings. The LMS interior access sphere design conforms to both IESNA LM-79 and EN 13032-4 standards, and the Spectraflect 98% sphere coating gives superior radiance uniformity, measurement accuracy and repeatability. Both 2pi directional and 4pi total hemispherical flux measurements are supported. Please note that LMS integrating spheres are available as part of complete Labsphere Illumia spectroradiometer systems.
Key Features of Labsphere LMS Light Measurement Integrating Spheres
Integrating Sphere Photometry
Since their invention in 1894, integrating spheres have been used for measuring the total luminous flux of lamps and light sources of any kind. The combination of a spherical surface with a highly reflective, diffuse Lambertian coating creates a uniform luminance over the entire sphere surface. The light received into a photodetector (or more commonly today, a spectroradiometer) is a known proportion of the total, regardless of the beam size or shape from the device under test. The total flux of an unknown lamp is not measured directly; instead this measurement is based upon comparison to a traceable standard lamp that is used to calibrate the integrating sphere system.
Purpose Designed for Lamp, LED & Luminaire Testing
Labsphere LMS light measurement integrating spheres are hinged, interior access designs with diameters of 0.25, 0.5, 1.0, 1.65, 1.95 & 3.0m. The sphere designs conform to IESNA LM-79-18 & EN 13032-4 standards, while the Spectraflect 98% sphere coating gives higher radiance uniformity, measurement accuracy and repeatability compared to lower reflectance coatings. The device under test can be placed either in the centre of the sphere for 4pi flux measurements, or for directional sources, you may use place the lamp outside the sphere at the 2pi forward flux port.
All LMS light measurement integrating spheres feature a height adjustable centre mount platform that can be held in either a base up or base down orientation. Electrical feedthrough is provided to the lamp base, while removeable internal baffles screen the device under test from the detector port.
To complete your integrating sphere system, available accessories include calibration lamps, auxiliary correction lamps, DC power supplies and spectroradiometers. For details, please see the Accessories tab.
Light Measurement Integrating Sphere Calibration
LMS light measurement integrating spheres are calibrated by substitution using a standard lamp of spectral radiant or luminous flux, depending upon the type of detector used, either a simple photometer or an array spectroradiometer.
Any lamp placed within an integrating sphere both emits light, but also absorbs a proportion of the radiation due to reillumination within the sphere. The degree of self-absorption of the device under test relative to the standard lamp used to calibrate the sphere can lead to a significant under-reporting of the flux of the test lamp, but this error can be eliminated by means of an auxiliary correction lamp. LMS spheres feature an auxiliary lamp port and baffle for this purpose.
Light Measurement Integrating Sphere Coatings
Labsphere LMS light measurement integrating spheres are coated with Spectraflect, a barium sulphate-based coating for the 300-2400nm spectral range with a nominal 98% peak reflectance. The coating exhibits a near-perfect Lambertian (or diffuse) reflectance, which means that the reflected radiance from the sphere surface is equal for all directions of view, promoting a higher level of measurement accuracy and repeatability regardless of the sample size and shape, or beam angle.
Labsphere LMS light measurement integrating spheres are available in 6 diameters from 25cm to 3m. All spheres are a “clam shell” interior access design that support both 2pi directional as well as 4pi flux measurements. Please note that LMS spheres are also available as part of turn-key Labsphere Illumia Plus 2 spectroradiometer systems.
Model | LMS-025 | LMS-050 | LMS-100 | LMS-165 | LMS-195 | LMS-300 |
Sphere Diameter | 25cm | 50cm | 100cm | 165cm | 195cm | 300cm |
2pi Port Diameter | 5cm | 15cm | 33cm | 53cm | 63cm | Optional |
2pi Port Frame Reducer(s) | N/A | 15 to 2.5cm | 33 to 15cm | 53 to 15cm | 63 to 15cm | Optional |
Sphere Coating | Spectraflect | Spectraflect | Spectraflect | Spectraflect | Spectraflect | Spectraflect |
Sphere Type | Clam shell interior access, benchtop mount | Clam shell interior access, benchtop mount | Clam shell interior access, floor mount | Clam shell interior access, floor mount | Clam shell interior access, floor mount | Clam shell interior access, floor mount |
Sphere Material | Spun aluminium | Spun aluminium | Spun aluminium | Spun aluminium | Spun aluminium | Fibreglass |
Max 4pi Lamp Size (LM-79) | 2.5cmØ | 7cmØ | 14cmØ | 23cmØ | 27cmØ | 50cmØ |
4pi DUT Mount | Height adjustable, base-up & base-down | Height adjustable, base-up & base-down | Height adjustable, base-up & base-down | Height adjustable, base-up & base-down | Height adjustable, base-up & base-down | Height adjustable, base-up & base-down |
Max Lamp Wattage | 100W | 400W | 1,500W | 4,000W | 5,000W | 10,000W |
Detector Port Qty & Diameter | 1 x 1.25cm | 2 x 1.25cm | 2 x 1.25cm | 2 x 1.25cm | 2 x 1.25cm | 2 x 1.25cm |
Temperature Probe Port Diameter | 2.5cm | 2.5cm | 2.5cm | 2.5cm | 2.5cm | 2.5cm |
The following accessories are either supplied as standard with a Labsphere LMS-series light measurement integrating sphere, or available to purchase separately. Please note that LMS spheres are offered as complete Illumia Plus 2 spectroradiometer systems.
Accessory | Model | Description |
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Port Frame Reducers (STANDARD) | Port frame reducers are supplied as standard for the 2pi port on the 50, 100, 165 & 195cm diameter spheres:
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Cosine Corrector (STANDARD) | PA-050-NCD | A cosine diffuser that attaches to a 0.5-inch detector port frame on an LMS-series sphere. An SMA fibre optic adaptor is machined onto the rear face of the diffuser to connect to a spectrometer. |
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Fibre Optic Adaptor (OPTIONAL) | SMA-050-SF | A fibre optic adaptor mounts onto a 0.5-inch port frame and couples light between a sphere and a spectrometer via an optical fibre. Inside face coated in Spectraflect (SF). |
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Calibration Lamps (OPTIONAL) | SCL-040 SCL-650 SCL-1400 | Calibrated reference lamps of spectral radiant & luminous flux. NVLAP (ISO 17025) accredited calibration. Available individually and in sets of three. Includes a lamp socket. Three power levels are available:
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Auxiliary Lamps (OPTIONAL) | AUX-650 AUX-1400 | Auxiliary correction lamps to correct the self-absorption of the DUT in comparison with the reference lamp. Attach to 1-inch port frames on LMS-series spheres. Available in two power levels:
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DC Power Supplies (OPTIONAL) | LPS-175-27 LPS-350-28 LPS-525-42 | Programmable, current regulated, DC power supplies to power Labsphere SCL calibration and AUX auxiliary correction lamps. Available in the following models:
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Spectrometers (OPTIONAL) | CDS-800 CDS-2600 CDS-3000 | Labsphere’s CDS-series of high speed array spectrometers connect via an optical fibre with SMA connector to a light measurement integrating sphere for the measurement of spectral radiant flux, luminous flux, chromaticity, CCT and colour rendering. Three models are available:
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Software (OPTIONAL) | INTEGRAL | Labsphere’s INTEGRAL software communicates with your CDS-series spectrometer and LPS-series DC power supply via the Photometry Control Module (available separately) to provide control of your light measurement sphere system and to record and analyse your measurement data. |  |
Temperature Probe & Monitor (OPTIONAL) | TPM-100TC-08 TPM-400TC-08 | Thermocouple temperature probes and monitors that are compatible with Labsphere’s INTEGRAL sphere software. Record the temperature within the integrating sphere chamber. The probe attaches via a 1-inch port frame. Two models are available:
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Integrating sphere spectroradiometer systems are used to measure the spectral radiant flux, luminous flux, colour and colour rendering of lamps, LEDs and luminaires. With LMS sphere sizes ranging from 0.25 to 3.0m diameter, any size or power of light source can be accommodated. It is important to choose a sphere that is large enough for the device under test (DUT) that you wish to measure. If the DUT is too large for the sphere, the radiance distribution within the sphere chamber will not be uniform and this will lead to significant errors in the measurement of luminous flux. Speak to one of Pro-Lite’s application specialists about the right sized sphere for your application.
Measurement of luminous flux can be performed in either a 2π hemispheric or a total 4π geometry, and Labsphere’s LMS integrating spheres support both types of tests. The 2π geometry is used with directional light sources (for example, spotlights) and the DUT is shone into the sphere through a 2π port. The 4π geometry places the DUT in the geometric centre of the sphere and is used whenever the light source emits into light into all directions (for example, a fluorescent or incandescent lamp).
It goes without saying that all LMS spheres incorporate an auxiliary correction port that allows you to compensate for the self-absorption of the device under test placed within the sphere or at the sphere port. Without this essential option, measurements of luminous flux, chromaticity and CCT would suffer from errors easily running into the many tens of percent.
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