How can you use integrating spheres to measure the quality of LED instruments

An integrating sphere is frequently used to examine luminaire or light source brightness, chromaticity coordinates, CCT, dominant wavelength, peak wavelength, etc. The traditional integrating sphere is the IS-*M, which LISUN has already stopped manufacturing in favor of the IS-*MA, which uses a molding method. It is your finest choice to take into consideration if your application calls for the measurement of a beam that is widely divergent.

It is an optical element that traps a light beam and makes it possible to assess the beam’s power in difficult circumstances. a beam that is widely divergent and might potentially fill the entire sensor aperture. This article describes in detail the IS-*M integrating spheres by LISUN, its detail and specifications and discusses what the equipment is used for, how it works and provides guidance on how to clean the device to improve its functionality.

Integrating Sphere | Ulbricht Sphere | Optical Spheres | IS-*M
The integrating sphere, also known as the photometric sphere, luminous flux sphere, etc., is a hollow sphere with an inner wall coated with white diffuse reflective material. To assess the luminous flux, color temperature, light efficiency, and other characteristics of the light source, a connection to the LISUN spectroradiometer and other equipment was necessary.

The integrating sphere (IS-*M) from LISUN is an optical tool that catches a light beam and enables the measurement of the beam’s power under various conditions. An integrating sphere’s internal surface has a widely diffused white coating because of its physical characteristics. The beam enters the sphere through a hole. Light reflects multiple times in each direction on the inner surface because of how widely it is dispersed. As a result, light is uniformly distributed across the whole inside surface of the spherical.

Due to the LED luminaries developed, to do 4π geometry testing, LISUN designed the Integrating Spheres With Holder Base which is easy to install the LED street luminaries.

Because of this, it is also frequently referred to as a light-integrating sphere. Generally speaking, the apparatus is used to test luminaires or light sources for luminosity, chromaticity coordinates, CCT, dominant wavelength, peak wavelength, etc. The IS-*M, a more conventional integrating sphere, is no longer produced by LISUN in favor of the IS-*MA, which makes use of molding technology. For the LED testing, IES LM-79 Clause 9.1.2 specifies the 4pi integrating sphere and 2pi integrating sphere. To answer the demands, LISUN created the photometric integrating sphere with side assistant opening and molding technology.

When using an integrating sphere, the light source must be mounted in the center of the integrating spheres before testing. The standard also outlines the many relationships between the surface area of the measuring object’s surface and the surface area of the integrating spheres inner wall. As a result, buyers must acquire an integrating sphere that is the proper size for their samples.

Moreover, the test environment must exactly adhere to the standard, meaning the test must be conducted in a space with a constant temperature of 25 degrees Celsius. It is now important to verify that the interior temperature of the integrating sphere is constant at 25 degrees, but because the light source will also produce heat, a constant temperature integrating sphere is needed to provide this guarantee. The cost of the constant temperature integrating spheres will be higher. However, purchasing thermostatic integrating spheres for personal use is not advised.

Product detail and specifications
When carefully examining the product’s specs, it must be noticed that the coating’s painting substance complies with CIE Pub. No. 84 (1989). The sphere walls are painted with BaSO4 coating integrating software (PTFE material is an alternative) in two different spectral ranges: 0.96 (450nm–800nm) and 0.92 (380nm–450nm). There is a fine diffuse with numerous reflections, the accuracy of () 1.5 percent, and reflectance of 0.8. Additionally, there are built-in test jigs for all working lamps for E40/E27, T5/T8/T12 tubes, and the base for testing LED and other luminaires.

All test samples can be inserted into the sphere in both the up and down directions. Built in are the power cord, power terminal, and auxiliary lamp position (the Auxiliary lamp is optional). Moreover, an integrated power cable and socket. The test lamp is easy to turn on, and there are built-in temperature sensors, two photodetector ports, one optical fiber port, and several typical integrated spheres.

LISUN created a molding technique to create an integrating sphere that is more rounded and produces more accurate test results. Also, the built-in cross laser can assist with positioning the reference lamp and the test lamp in the optical sphere’s middle.
When it comes to integrating sphere applications, the optical sphere collaborates with a spectroradiometer to detect photometry, colorimetry, and radiometry characteristics.

• For LEDs, LED modules, mini LED bulbs, and other small lamps, use the IS-0.3M/IS-0.5M standards. The range of the flux testing is 0.001 to 1,999 lm.
• For CFL or LED bulbs, use IS-1.0MA. Flux testing is performed between 0.1 and 199,990 lm.
• For CFL, LED bulb and tube, fluorescent light, and CCFL, use IS-1.5MA/IS-1.75MA. The testing flux range is between 0.1 and 1,999,900 lm.
• High power bulbs are IS-2.0MA or HID lamps. The range of the flux testing is 0.1 to 1,999,900lm.

What is measured by an integrating sphere?
In general, when used appropriately, the optical diffuser may eliminate tiny errors brought on by the uneven distribution of the incident light source on the detector or the deviation of the beam during measurement, improving the accuracy of the integrating sphere measurements. An integrating sphere must be used as an optical diffuser during precision measurement to lessen the aforementioned error.

The integrating spheres fundamental working concept is the capturing of light through the sample port. After multiple reflections inside the integrating spheres, it scatters rather evenly. When the integrating sphere is used to measure the luminous flux, the measurement results may be more precise. The integrating sphere can be used to reduce and even completely eliminate the divergence angle, measurement error, and light shape caused by the discrepancy in responsivity at various points on the detector. The criteria for a good integrating sphere are as follows:

1. A complete geometric sphere with the same radius must cover the entire inner surface of the integrating sphere.
2. For incident light of different wavelengths, the inner wall must have a neutral, uniform diffuse reflection surface with the same diffuse reflectance.
3. Both the light source and the integrating sphere must be thought of as abstract light sources that solely emit light devoid of actual particles.

These characteristics apply to the integrating sphere:

1. Lambert’s rule is followed by the inner wall’s uniform ideal diffuse reflection layer.
2. The reflectance of every point on the integrating sphere’s inner wall is the same.
3. The white coating’s diffuse reflection off the integrating sphere’s inner wall is neutral.
4. The lamp is the sole object inside the integrating sphere, and its radius is constant throughout.
5. The E-value of the window material is zero because it is neutral. The difference between the real situation and the ideal state must be addressed because it will lead to measurement errors.

How does an integrating sphere work?
With the quick growth of the LED sector, there are an increasing number of bulb types and a greater range of applications for LED lighting. One of them is flat lighting. Flat lighting is appropriate for indoor illumination in places like the living room, bedroom, hallway, kitchen, and balcony. Flat panel lights are energy-efficient, provide equivalent lumens, comparable color temperatures, and a high CRI at the same power as conventional lighting sources.

Currently, there are various integrated sphere-LED spectrum analyzers available on the market that are used to test flat lights. The test methodologies are various due to the various installation positions of flat lights in the integrating sphere as well as the variety of flat light types. The test results fluctuate significantly depending on the installation technique, with a maximum variance of 40%. They are all separate because there is no common normative norm. Spheres can be integrated in a variety of ways to test flat panel lights.

The issue of light suspension will arise regardless of whatever manufacturer’s equipment is used, therefore the buyer can take the optional inner platform into consideration when buying the integrating spheres. The new integrating sphere from LISUN just requires an inner platform because it already has a reserved port. It can solve the lamp and lantern positioning issue.

However, because an integrating sphere needs a 4 light source, it is not widely used in the market today to test flat panel lights. It is advised to use a goniophotometer while testing flat panel lights. The goniophotometer uses a 360-degree unbroken test angle to do a full-space test of a 4 or 2 lamp; this method has more accuracy than the integrating sphere since there is no inaccuracy in the influence of the lamp itself on the test environment.

How to calibrate an integrating sphere?
Simply said, one must insert the standard lamp in the middle of the integrated sphere, turn on the lamp with the calibrating current, close the Ulbricht Sphere, and begin the calibration process using the LISUN LMS-9000 Software. But the precise actions would be:

1. Attach the connecting wire’s red and black output terminal on the DC power source to one end, and the integrating sphere’s terminal to the other.
2. After putting the standard lamp in place, turn on the DC power switch and adjust the output current so that it matches the value listed for the output current on the report on the standard lamp calibration. It is necessary to warm up the standard light for 15 minutes.
3. Start the test software, select the spectral calibration button, enter the calibration dialogue box, and then check to see if the color temperature matches the value in the standard lamp calibration report. If it does, click Start and then OK in the pop-up dialogue box for the adjustment slit. The instrument will then finish the scan automatically. Just click once the file format has been saved.

How to clean the device?
Learn how to extend the integrated sphere’s lifespan and keep it in good condition there. This is due to the fact that the cleaner you keep it, the longer it will last you. A knife can be used to carefully scrape away small stains from the surface. Spray the area with specialist paint after scraping to hide any obvious color. Moreover, when inspecting and cleaning the integrating sphere’s exterior surface, keep dust out of the sphere.

It is strictly forbidden to clean the interior of an integrating sphere using a cloth. When not in use, the integrating sphere must be kept covered so that dust cannot collect on it and it is shielded from damage. Also to protect your hands when working in the integrating sphere, we require that you put on white gloves. Every week, you should do an inspection of the integrating sphere spectroradiometer system and note the findings in the inspection log.

Integrating Spheres Set Up IS-XMA

FAQs
Is it possible to measure an automobile’s brightness using an integrating sphere?
When a vehicle is utilized as a light source, the integrating sphere is used to check its luminosity, chromaticity coordinates, CCT, dominant wavelength, and peak wavelength. The brightness of individual LEDs and LED lighting fixtures can be measured using this device.

What is the importance of the maintenance of the device?
Learn how to extend the integrating spheres lifespan and keep it in peak shape there. This is due to the fact that the cleaner you keep it, the longer it will last you. A knife can be used to carefully scrape away small stains from the surface. Spray specialty paint over the area after scraping to hide any lingering color.

Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.

Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator Guns, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.

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