Integrating sphere maintenance skills and common issues will meet

An integrating sphere collects electromagnetic radiation from a source usually external to the optical device, usually for flux measurement or optical attenuation. Radiation introduced into an integrating sphere strikes the reflective walls and undergoes multiple diffuse reflections.

Integrating Sphere

Because of the frequent use of integrating sphere, many customers who have purchased spectrometer with integrating sphere are also very concerned about the maintenance of the integrating sphere. Correct use of the integrating sphere and correct maintenance of the integrating sphere will extend the service life of the integrating sphere for many years. The points will be extended for many years. The integrating sphere maintenance is divided into three aspects, namely the point maintenance of the integrating sphere coating, the point of the integrating sphere circuit maintenance and the maintenance of the integrating sphere fixed device.

Then, let’s introduce these three maintenance methods. I hope to help everyone. The main content is as follows:
1. Integrating sphere coating maintenance: Due to the uneven chemical coating of the integrating sphere, some small dust and debris will be attached. When processed, use a soft brush to gently wipe and paint in a certain direction.

Before the test, please hold the light bulb carefully before the test. Do not fall or touch the coating of the integrating sphere to prevent damage. After the test, immediately turn off the power measurement of the lamp in the integrating sphere, remove the fixed device and close it in time to close integrating sphere to prevent debris from entering.

2. Maintenance of integrating sphere circuits: Pay attention to grounding and select the correct power supply, regularly maintain the external inspection of the outer and whether the wire of the carrier wiring box is damaged.

3. Integrating sphere fixed device: ensure that the contacts of the lamp head work normally, and it is not damaged or pressed down. Make sure that the wiring of the fixed device of the light bulb is correctly connected.

The integrating sphere is low and the standard value is low when testing the light flux of the lamp, and it will even reach 20 % of the deviation (the principle problem of equipment, the same domestic and foreign equipment). Test the optical flux of the optical meter with goniophotometer, but the test efficiency is low. About 8 hours tests are tested about 8 pieces of lamps per day. It can not full meet the large test quantity requirement company.

Principle of integrating sphere spectroradiometer system:
The light emitted by the lamp is shot on the inner wall coating of the integrating sphere. After multiple reflection of the surface with a mansion with a mansion with a long reflex material was applied by the inner wall, the light that is uniformly illuminated into the spectrum radiation meter to form test data.

Therefore, there may be several reasons that affect the test data when using the integrating sphere testing light flux:
• Different distribution of standard lights and measuring sources will cause deviations. The larger the angle, the greater the deviation will be.
• The standard lights are different from the size of the lamp.
• The adsorption of the appearance color of the tested lamp will reduce the reflection luminous passage and cause deviation.
• After a long period of use of the integrating sphere, the reflectivity decreases after a long time.

From the above four points, the time flux of the small angle of the small angle of black is sometimes 20 % lower than the actual optical flux, which makes the integrating sphere meaning when testing the optical flux.

The integrating sphere uses standard light calibration during testing. If the ideal data cannot be achieved after calibration or in order to make the calibration data more accurate, there is a correction coefficient inside the software.

According to this principle, as long as you know the accurate light flux of a light, the test data is the test data as X when the correction coefficient is 1, and a coefficient of the known accurate light flux / x is the correction coefficient. The input of the correction coefficient page in the figure above is inconvenient. You can enter the correction coefficient in the self -absorbing position in the figure below. The results are the same.

After input the calculated modification coefficient, the test results show that the test results are the same as the amount of luminous flux is determined, and the error is within 2 %. The calculated correction coefficient test is accurate, testing whether the other lights are accurate. After nearly half a year of verification, the same type of lamp (down lights / spotlights, etc.), and the structure size is not large (such as 3W / 6W / 9W, etc.) , A coefficient can be used.

Save this coefficient. In the future, the same type and the size of the size can be used. The tests tested by this method have excluded the traditional impact of the integrating sphere factors such as the angle and color, which is mainly related to the shape and size of the lamp.

It is known that the lamp with accurate light flux can be tested in a goniophotometer. The goniophotometer of different types of lights of different types and sizes needs to be only measured once, and the coefficient can be determined. There is no need use the goniophotometer to use, which greatly improves the test efficiency, so that the distributed optical meter only measures the lamp with light requirements or structural design when the light design is tested once, and the subsequent test uses the integrating sphere.

At present, the new GB / TT33721 lamp reliability test is required to be tested once in the initial time, testing once after the reliability test, and testing once after the life test. If the improvement method is used to test, it can fully meet the test requirements. And there is no need to worry about the equipment problem affecting the test progress. New methods can increase test efficiency by 3-4 times.

The integrating sphere will cause errors during actual measurement. Why? Let LISUN introduce it to you:

The reason why the actual points used have an error is mainly because the opening, inside of the sphere and the internal dried material are not ideal.

1. Internal cover of the integrating sphere: In the measurement of the power distribution curve of the light source spectrum or the use of the integrating sphere as a full light source, there is generally a cover inside the integrating sphere. However, the actual working status of the integrating sphere is deviated away from the ideal situation after the cover is added.

2. Effects of coating: Because the reflectance of coating is related to the wavelength, the spectral characteristics of the lighting of the light will change. In particular, when the reflectivity of the coating is very high, a small amount of changes in the spectrum reflection ratio of the coating material will make the radiation degree of radiation a considerable change. Therefore, the coating generally needs to use the spectral reflection ratio to the same flat and Langbo’s good material as the coating. Commonly used are sulfate, magnesium oxide, and polytefluoroethylene.

3. Impact: Since the operating characteristics of the actual integrating sphere are not ideal, the radiation degree from the outlet window is not completely uniform. Therefore, the size of the outlet window and the integrating sphere should have a certain proportion relationship. In engineering practice, it is generally believed that if the uniformity of the radioactiveness is about 1%, the diameter of the outlet window is best than one -tenth of the sphere diameter. In addition, because the receiver is impossible to attach the inner wall of the integrating sphere during actual work, the internal split light of the integrating sphere cannot enter the receiver, and the error is generated. In fact, some people are concave under certain conditions, so that the transition light cannot enter the receiver directly, and to a certain extent to replace the screen, thereby reducing errors.

4. Impact of the size of the integrating sphere: The size of the integrating sphere in derivation does not affect the uniformity of the light illuminance on the surface of the integrating sphere. However, due to the loss of the internal light of the integrating sphere, it is bound to bring losses. It can be seen from the law of the square. The larger the integrating sphere, the smaller the lightness on the outlet window. However, the larger the integrating sphere, the more the objects in the screen and the other objects in the sphere can deviate from the ideal conditions of the integrating sphere, improve the uniformity of the radiation degree at the spot sphere, and then improve the test accuracy.

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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