Lumen test difference between integrating sphere and goniophotometer

As well as we know that for the LED luminaires lumen test, the CIE121: 1966 Clause 6.1, CIE127-2007 Clause 6.2 and IES-LM-79-08 Clause 9.0 are mentioned two luminous flux test method: the first is adoption integrating sphere+photometer or spectrometer(recommend by CIE121: 1966 Clause 6.1.1, CIE127-2007 Clause 6.2.and IES-LM-79-08 Clause 9.0), this kind of test method is relative measurement method on lumen test; the second is photometric method which is adoption goniophotometer, this kind of test way is absolute measuring method. If adoption integrating sphere and photometric method to test same one LED lamp, we will find luminous flux data of two test method have big difference. This article is mainly discuss luminous flux test difference at integrating sphere and goniophotometer.

The principle of integrating sphere measuring total luminous flux by calibrated standard lamp. Due to there will be use a calibrated standard lamp, so there’s no need to know the integrating sphere’s output luminous flux, we can calculate the SSL product’s luminous flux by compare with standard lamp. Generally speaking, the integrating sphere test method suitable for small size LED lamp to measuring lumen and color parameters, this is lumen relative test method, moreover, the integrating sphere test method have quick test speed and it needn’t dark room advantages etc. Normally, if lamp size is small or like single LED, the test result and accuracy will be much better.

If adoption integrating sphere method testing big size LED luminaires, it have some better disadvantages compared with photometric method. When use integrating sphere test LED luminaires, there have a fact that the LED luminaires have different types, such as single LED, LED bulb, LED luminaires and others, the type of LED luminaires have big influence for final total luminous flux measurement. Meantime, integrating sphere test method need to do calibration procedure. Normally, if test LED luminaires, the standard lamp have to keep same emission characteristics with tested LED luminaires, the standard lamp adoption white LED will be best way. Of course, other type lamp also can used as standard lamp, but the test accuracy will be impacted. The test way will bring some difference, usually we use the 4π test way to test a lamp which emitting the lighting at 360° direction and the tested lamp should be placed in the centre position of the integrating sphere(recommend by IESLM-79-08 Clause 9.2.5). This is the best way to test LED luminaires; if the tested luminaries emitting the lighting at fixed direction, such as LED panel, LED street light or others, we need use 2π test way which means test the luminaries should be mounted on the one side of integrating sphere(recommend by IESLM-79-08 Clause 9.2.5). For the 4π test way; if the tested luminaries output power is too big or the the lamp shell have large size, there will be happen self-absorption effect more or less, then we need to use a auxiliary lamp(recommend by IESLM-79-08 Clause 9.1.5) to avoid the error. Generally speaking, the integrating sphere method is suitable for the compact LED and small size LED lighting. The test result of the luminaries flux can be achieve high accuracy and stability by this way; if use integrating sphere testing large size LED luminaries, the integrating sphere method have obviously defect, this time, the the luminaries flux data is not accurate and stable.

Adoption goniophotometer measuring total lumen which is photometric method, and this way have small limitation on the lumen test. The test principle of photometric method is use goniophotometer measuring all direction’s intensity distribution (or show the illuminance of light source at limited distance), through collection the intensity data at different direction to calculate the total lumen. Compared with the integrating sphere method, due to the difference of test light source’s intensity distribution, the photometric method don’t exist error in the theory, as the photometric method is absolute test method on the lumen test. It doesn’t need calibrated total luminous flux standard lamp, but it need longer test time for each sample. The photometric method which will adoption goniophotometer device, and there will be mentioned the type C Goniophotometer(recommend by IES-LM-79-08 Clause 9.3.1 and CIE121:1996 Clause 3.2 etc), dark room, test distance(mentioned by IES-LM-79-08 Clause 9.3 and CIE121:1996 Clause 6.2.1.4).

The difference of testing total lumen output consist of type of goniophotometer, test method(CIE121: 1996 Clause 3.4.2, Clause 3.4.1 and Clause 3.4.3), test distance and detector level etc. According to different type of LED luminaires, we can adjustment the relevant test method or testing device, such as if tested luminaires belong to narrow beam angle SSL product, we can use compact goniophotometer; selection Type C Goniophotometer, adjust test distance, choose higher level Class L detector(detector details classification description here: article-id-70.html) which can help achieve high precision measurement. In the practice testing, the photometric method can achieve luminous flux data’s highest measurement, due to some limitations inherent of integrating sphere test method, it’s impossible to remove the test tolerance, the only we can do is try best to reduce the test tolerance; but for the photometric method, there almost haven’t too much limitations and we can replace the test instrument, adjustment system configuration and change test method to fix this test tolerance.

As explained above, the most simple way to measuring LED luminaires luminous flux is adoption integrating sphere and photometric meter, this way is meet visual flux spatial demand, we can use a fixed front-end photometric meter to measure the total flux and the test time is fast and convenient. By comparison with a standard light source which keep have similar spatial and spectral distribution characteristics of tested luminaires to measuring luminous flux, so this way will be need use a calibrated standard lamp. Comparing with goniophotometer, the integrating sphere and photometric meter have high test speed, but when tested LED luminaires have different spatial intensity distribution characteristics from standard lamp, it’s easy to cause test tolerance. This kind of test tolerance is hard to fix, so it should be adoption use a good design geometry integrating sphere and use standard LED standard lamp which have similar emission characteristics with tested LED luminaires to reduce this error.

As mentioned previously, if the shape of tested lamp is similar with tested luminaires, then the integrating sphere method will have better test accuracy. When measuring luminous flux, for the LED bulb, small size LED luminaires and tube which beam angle more than 180°, we should adoption integrating sphere and spectrometer to do 4π test. As for the big size LED panel, LED street lamp and traffic lamp which beam angle less 180°, if need adoption integrating sphere method, then the integrating sphere should have side opening structure to do 2π test or use auxiliary lamp for assistance test, but this way have complex test procedure and test result is uncertainty. For these small beam angle luminaires, the best way is adoption goniophotometer method and working on the dark room, this can make sure high accuracy. But when adoption goniophotometer method, we have a clear understanding for test difference of different test method. Normally, like the LED panel, the best test method is C-γ; for the traffic lamp and spotlights will choose B-β test. At the same time, both test methods are need at dark room environmental, comparing with integrating sphere, the goniophotometer need more professional test environmental and professional engineer. In summary, the measurement principle, environment and test methods of the integrating sphere and the distributed spectrometer are different, and the measurement results are not comparable. We can choose the right way to test according to different standards and different requirements.

In summary, both integrating sphere and goniophotometer method have different measuring principle, environmental and testing methods, the both measurement results are not comparable. We can based on different standards and requirements to selection suitable test way.

In order to better compared test result, we used the spectrometer, integrating sphere and goniophotometer to testing LED bulb and street lamp. The test report as below, we can refer this.

Lumen test difference between integrating sphere and goniophotometer

Lumen test difference between integrating sphere and goniophotometer

Lumen test difference between integrating sphere and goniophotometer

Lumen test difference between integrating sphere and goniophotometer

Improve the accuracy of the LED flux testing in the Sphere

Abstract: According to the particularity of LED luminous flux measurement, unique optimization is adopted in the design of the integrating sphere for LED measurement combined with the diffuse materials of high reflectivity, which makes the system stability and accuracy have great improvement. The experimental results show that the system stability and consistency is much higher than other common LED test system. It is the system which is really suitable for LED optical parameters measurement.

Keywords: LED Measurement, Integrating Sphere, A molding Integrating Sphere, Diffuse Reflection

Introduction: Different with the traditional light source, the luminous flux measurement of LED light source has posed a big challenge to the equipment in testing the veracity in the process of using the integrating sphere to test luminous flux. On one hand, compared with the traditional light source, usually, LED has much stronger directivity, and will not shine evenly in whole space. This feature makes the distribution of LED direct light in the surface of the integrating sphere uneven. This uneven distribution will cause the direct light of different LED has different reflection features of the detector. Because the position of the detector mouth and the position of the baffle are fixed, the direct performance of various reflection distributions is signal fluctuation. In the ordinary testing system, there exist the differences in LED of different positive divergence angle, the same LED of different placed direction, the same direction with different position. Even the rated luminous flux is the same; the actual measured value is different. Based on the customer’s verification result, the effect of LED placed direction of ordinary LED test system on the luminous flux measurement result is always more than 50 % (the difference of the maximum signal and minimum signal of the same LED measured in different direction).

When measuring the different lighting angle of different LEDs, since the distribution difference of the surface of the inside integrating sphere makes the distribution of the direct reflection have different effect on the detector, it directly affects the difference of the accuracy of the measurement (as shown in picture 1).

Improve the accuracy of the LED flux testing in the Sphere

Picture 1: Different lighting angle has different effect on LED measurement

On the other hand, LED test system usually uses halogen tungsten lamp as the standard light source, compared with LED; the standard lamp used has big difference both in the appearance, the distribution feature of lighting and in the spectral characteristic. Therefore, the difference of the two should be revised by the absorption coefficient.

Analysis:
The inside reflection characteristic of the integrating sphere is one of the crucial factors that make the LED directivity have the impact on the measurement accuracy. In the ordinary LED test system, the reflectivity and the Lambert character of the integrating sphere surface coating are not ideal. One reason is the low reflectivity, and the other reason is the poor diffuse characteristics. The result of the integrating sphere surface of low reflectivity is that the direct light of LED gradually attenuates after few times of reflection. However, during the whole process of mixing light, the direct irradiation light and reflection light have held a very large proportion, which has made a leading role. And in some conditions, low reflectivity materials will cause strong shadow effect on the back of the baffle probe. However, it is the straight reflected light and shadow effect that leads to the inaccurate measurement.

Moreover, lower diffuse reflectivity will seriously affect the attenuation of the signal. Since the light has been reflected for many times in the integrating sphere during the process of the light measurement, each reflection will cause certain attenuation, but the impact of the reflectivity degree on the light intensity has been strengthened after many-times reflection. For example, the reflected light has been reflected for 15 times in the integrating sphere, if there is 5% difference between their reflectivity, the signal attenuation may exceed more than doubled. Actually, the reflectivity difference in the integrating sphere is far more than this.

The current LED test system has not been used as the standard LED for the standard light source. In the process of measurement, we still choose to use the standard halogen tungsten lamp with stable driver as the standard light source. Since there is a big difference in the external structure between the standard lamp and the measuring LED, including the light absorption effect of LED holder and the difference between the standard lamp installation position and LED installation position, all these are the important factors that affect the accuracy of the test result.

Solution:
LPCE-2 Spectroradiometer & Integrating Sphere LED Testing System developed by Lisun Group is a set of LED test system, which completely meets LM-79 and the relevant requirement of CIE, has effectively solved various shortage of the traditional LED test system.

Compared with the massive assembled production technology for the traditional integrating sphere, Lisun Group has adopted the A Molding technology to produce the integrating sphere, the shape of which completely fits the spherical structure of 4π or 2π. Lisun Group has also adopted the high reflection and diffuse rate coating to make the open position design of the lamp fit the detector position. Even using the LED of extremely strong directivity or using the position mode in the extreme condition, this improvement has made the test result keep a good consistency. Know more information about Integrating Sphere with Side Assistant Opening and Constant Temperature Integrating Sphere, please refer to our website: Integrating Sphere.

Improve the accuracy of the LED flux testing in the Sphere

Picture 2 A Molding Integrating Sphere VS the traditional Integrating Sphere

LPCE-2 has adopted the standard halogen tungsten lamp as the standard lamp combined with the optional auxiliary lamp scheme to make up the impact of the difference between the measuring LED holder and the standard lamp holder on the test result. This standard lamp has been strictly calibrated by the calibration laboratory of Lisun Group; the test result can be traced up to NIM. The power supply used by the standard lamp and the auxiliary lamp is WP3005 Digital CC and CV DC Power Supply, the accuracy of which can reach 0.0000.

Aiming at the above problem of the accuracy of LED test result, LPCE-2 test system is used to conduct the corresponding test. The test condition is as follow: using green 5LED of high brightness, the power is about 0.35W, the lighting angle is about 30°. LPCE-2 test system is used for 9 kinds of measuring positions, which respectively represent the possible LED position mode, as shown in picture 3.

Improve the accuracy of the LED flux testing in the Sphere

Picture 3 Different LED position modes

Conclusion:
The relationship between the measured flux and LED position mode is as shown in chart 4 and chart 5. Seen from the test result, even in the most extreme condition, namely when LED is placed in the front and back of the open month of the detector, the peak value of the luminous flux test result is still less than 5%. That is a very good test result. In the actual testing process, the repeatability error of LED luminous flux measurement is far less than 0.1%. Thus it can be seen that the test result of LPCE-2 test system of Lisun Group is reliable and stable, which can provide a reliable guarantee. This set of standard system not only has greatly supported the study, development and production of LED, but it is also the ideal choice of measuring the optical property of LED industry.

Number	Angle	Lumens	Percentage
a	0	17.35	100.00%
b	45	17.39	100.20%
c	90	17.00	98.00%
d	135	16.91	97.50%
e	180	16.75	96.50%
f	225	16.45	94.80%
g	270	16.36	94.30%
h	315	16.65	96.00%
i	360	17.34	99.90%

Chart 4 the corresponding flux value of different LED test position

Improve the accuracy of the LED flux testing in the Sphere

 Chart 5 the relationship of LED test position and flux

Types & Test Methods of Luminaires Goniophotometer

The most critical factor that affects the quality of lighting is the luminous distribution performance of lamps. Using scientific testing methods and selecting the appropriate test instrument is the basis of obtaining accurate luminous distribution properties of luminaires. The test of luminaires’ luminous distribution is an important part of luminaire design and lighting design for quality control. Especially with the development of new sources and new lighting technology, it presents new challenges for the test of luminaire luminous distribution. Thus, Lisun has developed various goniophotometers which adopting different test methods for testing luminous distribution.

1) Moving Detector Goniophotometer

The method of goniophotometer to test total luminous flux is spectrophotometry. The principle is to test the luminous intensity of light source at different directions (or the illumination at a given distance from the light source), and then to calculate the total luminous flux by the data of luminous intensity in many different directions. According to LM-79 Clause 9.3.1 standard, only type C goniophotometer with moving detector can be accepted. In this kind of goniophotometer, the photometer head is fixed, and is located in the optical axis line. During the measurement, the lamp just need to do spin motion, and the mirror rotates around the tested luminaire, and reflecting the optical signal into the detector. The tested light source and the normal of photo detector enter into a certain cone angle. Therefore, the movement airflow has less impact on the lamp temperature for this kind of goniophotometers.

During the test, the tested lamp will keep burning position and be fixed, near field detector move together with the big mirror in a line, and the far field detector will move with the big mirror synchronously. The detector will always sense the light directly from the luminaries. Lisun LSG-3000 Moving Detector Goniophotometer is full meet LM-79 Clause 9.3.1 request. It is more applied in North America, mainly used in large-scale experimental laboratory or third party testing organization. Its working principle is shown as Figure 1.

Types & Test Methods of Luminaires Goniophotometer

Types & Test Methods of Luminaires Goniophotometer

Figure 1 Lisun LSG-3000 Moving Detector Goniophotometer

2) Rotation Luminaire Goniophotometer

Lisun LSG-1800B/LSG-1700B/LSG-1600B High Precision Rotation Luminaries Goniophotometer carries out measuring methods of fixed location and rotating luminaries. It can work by double pillars structure and single pillar structure to realize C-γ, A-α and B-β measurement solution, it fully meets CIE, IEC, LM-79, GB etc standards. LSG-1800B adopts Japanese Mitsubishi Motor and German Angle encoder System to keep the test accuracy to 0.0017degree. It is widely used in optical industry laboratory. It is used to test for LED street luminaries, indoor luminaries and mining luminaries’ photoelectric parameters.

The detector of this kind of goniophotometer is fixed at a certain distance from the lamp, and lamp is mounted on a turntable which can be rotated on horizontal and vertical direction. The main vertical axis of the turntable is fixed, and the horizontal axis can be moved. Under the control of computer, the motor drives the vertical axis to rotate, and the photo detector will test lamp’s luminous intensity values in the different direction on the horizontal plane. When the measurement on a plane is completed, the motor of horizontal axis will drive lamps to turn at an angle, and then the photo detector will measure the luminous intensity distribution on another plane. So as the repeated progress, the vertical axis continuously rotating, and horizontal axis intermittently move, to achieve the measurement of light intensity distribution data in all directions of space. Since this kind of goniophotometer will continuously rotate and change the status of luminaries, it is not suitable for gas discharge lamps etc. whose photo and electrical parameters will be easily influenced by its working conditions. However, it is more suitable for grille lamps testing, and mainly for LED lighting manufacturers and retailers to measure the quality of the lamps.

3) Goniophotometer for Automotive and Signal Lamps

For road lighting photometric test, the current street light is mostly gas discharge lamp. According to CIE and FMVSS108 standard requirement, for the measurement of gas discharge lamps, it requires that luminaires can not be overturned. Thus, we generally use goniophotometer with moving mirror to do the test. LSG-1950 is the CIE A-α goniophotometer. It is mainly used to measure transportation industry luminaries such as traffic signal lamp, public transport, train and space ship luminaries. The photometer head keeps static and faces to the teat sample while the test samples rotates around both horizontal axis and vertical axis, so the luminous intensity and illuminance of the tested lamp or luminaires can be tested.

Goniophotometer is a large precision optical test equipment, while its measurement is a very professional work. The test equipment, laboratory construction and operating personnel is three important aspects of affecting the measurement results. On test equipment selection, we must consider the properties of the beam of lamps, especially the measurement of street lights and other outdoor lighting. And testing methods must comply with CIE far-field photometry principles, with particular attention to stray light impact of test equipment and laboratories. To ensure the accuracy of test results, in all aspects of the test equipment, we should properly place the corresponding diaphragm to eliminate stray light.

EMI Measurement Application and Relative Test Standards

Along with the technical development, more and more digital and high speed electronic and electric devices are widely applied to vary industries. Those equipments push the society developing, and the same time they bring the electromagnetic pollution problem to the society. Electromagnetic pollution, water pollution and air pollution are the three big pollution sources for modern life. Go with series electromagnetic problem, IEC 61000-4-4, IEC 61000-4-5, IEC 61000-4-11, CISPR -16, CISPR-15 and other relative standards are introduced by IEC. The main purpose for those standards is to limit radio disturbance and put forward the method of measurement of electronic and electric device, so that to decrease the society problem which brings by electromagnetic disturbance.

As we know, the test object for EMC is electronic and electric device, among them, lighting is an important part which should do the EMC test naturally. Like FCC from America and CE from European Union, both of them request EMC measurement of LED lighting device. When talk about electromagnetic disturbance, generally it indicates two disturbance sources, one is conductive interference (EMS), it means that the disturbance signal will affect the EUT by conducting medium or public power supply; according to FCC, the LED lighting should do the conductive interference test at the frequency of 0.15MHz to 30MHz; but according to CE, it requests to do the test at the frequency of 9KHz to 30MHz. The other is radio disturbance (EMI0, it means the disturbance signal will pass to electric network or device by the way of space coupling; according to FCC, the LED lighting should do the radio disturbance test at the frequency of 30MHz to 1GHz; but according to CE, it requests to do the test at the frequency of 30KHz to 300MHz.

For EMI test, the International Special Committee on Radio Interference (CISPR) introduced CISPR-16 Radio Disturbance and Immunity Measuring Apparatus-Measuring Apparatus; for lighting industry, they introduced CISPR-15 Limits and Methods of Measurement of Radio Disturbance Characteristics of Electrical Lighting and Similar Equipments. Meanwhile, some countries push their own Lighting EMI test criterions according to their real situation, like EN55015-2007(quote CISPR-15) from EU counties, GB17743-1999 from China and etc. For EU countries, EN55015 is applied to the traditional lightings which radio disturbance field exceeds 1000Hz, like incandescent lamp luminaries, fluorescent lamp luminaries, self-ballasted lamps and etc. generally, the frequency of the traditional lamps will not exceed 30MHz, the corresponding radiated electromagnetic disturbance limit as table 1. But for LED lighting, the frequency will exceed 30MHz, so according to CE, the frequency scanning range should be from 30MHz to 300MHz.

Table 1:

Radiated Electromagnetic Disturbance Limits
Frequency	Limits for Loop Diameter Db (µA)
	2m	3m	4m
9KHz to 70KHz	88	81	85
70KHz to 150KHz	88 to 58**	81 to 51**	75 to 45**
150KHz to 2.2MHz	58 to 26**	51 to 22**	45 to 16**
2.2MHz to 3.0MHz	58	51	45
3.0MHz to 30MHz	22	1.5 to 16***	9 to 12***

Base on CISPR16, Lisun Group developed two EMI test systems. According to the standards for traditional Lightings and new LED lightings, the frequency scanning range is different. The scanning frequency for KH3962 is 9 KHz to 300MHz, which is applied to LED and traditional lighting test; the scanning frequency for KH3961 is 9 KHz to 30MHz, which is applied to traditional lighting test. Both of them input three data to judge if the EUT can pass the test or not, that is PK, QP and AV. And user is freely to setup the standards (like GB17743, FCC, EN55015, GB4343) directly in the software.

Surely, besides the lighting industry, KH3962/KH3691 EMI test system is widely used in other electronic and electric industries, like Captial power system Ltd from India, Lumitec Ltd. from Thailand and other companies. The reason why Lisun Group wins so many trust and support from world famous companies and third labs is because we always practice the motto of right products, right price and right service. See from the feedback of our customers, we enjoy good reputation among our customers. No matter in the pass or future, Lisun Group will always give back the qualified products and superior service to our customer.

The Lighting Product EMC Problem and Testing Technology

LEDs and LED luminaires with high light efficiency, longer lifetime, better energy saving and environmental friendly advantages to achieve top position on the lighting industry, like indoor and outdoor lighting application. With the introduction of various national support policies, there appeared many LED lighting products manufacturer, but the quality of LED lighting products is not good well which influence the LED lighting product’s marketing promoting more or less. According to market quality checking, the failure rate of LED lighting product reach to 39%, most of failure products related with harmonic currents, surge impact, harassment voltage electromagnetic compatibility test items. Electromagnetic compatibility (EMC) is an important factor affecting the reliability of LED lighting products.

1. EMC Test Standards:
There haven’t LED special standards focus on EMC test, the current practice is based on the field of LED lighting products, refer to the implementation of the relevant standards. Such as automotive LED lighting products should refer to CISPR25<Limits and test methods of protect vehicle receiver from radio disturbance characteristics>, ISO7637-2< Road vehicles – Transient conduction from conduction and coupling of electrical disturbances along supply lines> and ISO11452< EMI electromagnetic energy – Component test methods for road vehicles narrowband radiated> etc EMC standards, this article will not discuss them here. The point need discuss is general purpose LED lighting products (except automotive lighting, aircraft lighting, photocopiers and other special LED lighting equipment) EMC test standards, as shown in Table 1 below:

The Lighting Product EMC Problem and Testing Technology

2. EMC Test Item:
LED lighting product’s EMC test item included EMI and MES. EMI mean electromagnetic interference, test LED lighting products may cause performance degradation or damage to generate electromagnetic disturbance of other things (including equipment, systems, people and animals and plants). EMS mean electromagnetic susceptibility( immunity test), test LED lighting product’s immunity ability for electromagnetic disturbances such as lightning, ESD static test and the fight against ringing waves immunity.

The Lighting Product EMC Problem and Testing Technology

The Lighting Product EMC Problem and Testing Technology

The table 2 list EMC test items of LED lighting products which inlcuded main test intem, main test equipment, test environmental. The following will focus on the EMI test, electrostatic discharge and surge test.2.1. EMI Test:EMI(Electromagnetic Interference) included conducted interference and radiated interference. Conducted interference refers to the signal coupling through a conductive medium (interference) on an electric power network to another network; Radiated interference is the source of interference to its signal coupling through space (interference) to another radio network. In high-speed PCB and system design, the high-frequency signal line, the integrated circuit pins, various types of connectors so may become a source of interference with the antenna radiation characteristics, capable of emitting electromagnetic waves and affect other systems or to other subsystems within the system normal operation. As we know, the test object for EMC is electronic and electric device, among them, lighting is an important part which should do the EMC test naturally. Like FCC from America and CE from European Union, both of them request EMC measurement of LED lighting device. When talk about electromagnetic disturbance, generally it indicates two disturbance sources, one is conductive interference, it means that the disturbance signal will affect the EUT by conducting medium or public power supply; according to FCC, the LED lighting should do the conductive interference test at the frequency of 0.15MHz to 30MHz; but according to CE, it requests to do the test at the frequency of 9KHz to 30MHz. The other is radio disturbance, it means the disturbance signal will pass to electric network or device by the way of space coupling; according to FCC, the LED lighting should do the radio disturbance test at the frequency of 30MHz to 1GHz; but according to CE, it requests to do the test at the frequency of 30KHz to 300MHz.

In the lighting industry, when testing EMI frequency range at 9KHz~30MHz, there have two ways: The first is use Antenna and EMI Receiver which according to CISPR15, EN55015 and GB17743. For the low-frequency magnetic fields equipment which may produced by lighting luminaries, it need to adopt the provisions of tricyclic CISPR16-1-4 low frequency magnetic field antenna measurement radiation harassment. This need use three Loop Antenna and EMI receiver working together to measure it, and the testing must operate at inside of shielded room. Note: the three loop antenna made X direction, Y direction and Z direction’s low frequency magnetic field component converted to RF signal, and supplied to a receiver via three channels of EMI coaxial switch; The second way is use LISN, the testing system include EMI Receiver, Artificial Network Power, LISN and software. Conduction disturbance test system for measuring normal working lighting and lighting equipment’s harassmen which produced by power port. LISN achieve isolation RF signal, sampling, impedance matching, and provide electricity for EUT channel, EMI receiver for RF signal measurements and finally analyzed by EMI testing software, processing and sentenced limit. The testing must operate at inside of shielded room.

At the meantime, the testing EMI frequency range at 9KHz-300MHz will be use CDN. The CISPR15，EN55015 and GB17743 standards are also mentioned another way to measuring lighting equipment’s radiation harassment electric. that’s CDN common-mode terminal voltage method. The CDN test method include EMI Receiver, CDN and Attenuator, the testing can operate at inside of shielded room.

Base on CISPR16, Lisun Group developed two EMI test systems. According to the standards for traditional Lightings and new LED lightings, the frequency scanning range is different. The scanning frequency for EMI-9KB is 9 KHz to 300MHz, which is applied to LED and traditional lighting test; the scanning frequency for EMI-9KA is 9 KHz to 30MHz, which is applied to traditional lighting test. Both of them input three data to judge if the EUT can pass the test or not, that is PK, QP and AV. And user is freely to setup the standards (like GB17743, FCC, EN55015, GB4343) directly in the software.

2.2. Electrostatic Discharge Test:

LED is semiconductor device, under LED manufacturing, assembly, transportation, storage, production of equipment, materials and the operator all of these factors can bring static losses of LED which caused leakage current increases, the light fades increase, or even “dead lights” phenomenon. Electrostatic discharge will caused influence and damage for reverse leakage current, forward I-V characteristic and luminous flux of LED product. Electrostatic discharge is one of the important factors affecting the LED and LED lighting product reliability.

LED chip is key part of LED lighting product. For LED electrostatic discharge immunity testing should follow the relevant international standards such as the American National Standard ANSI / ESD STM5.1, ANSI / ESD STM5.2, the IEC(International Electrotechnical Commission) standard electronic JESD22-A114D, JESD22-A115-A, the US military Party standard MIL-STD-883 and so on. Lisun Electronic Shanghai office R & D designed and developed ESD61000-2 Electrostatic Discharge Simulator which is designed according to LEDs static-sensitive level and characteristics, it applied with Machine Model (MM) and Human Body Model (HBM) electrostatic discharge test, electrostatic discharge voltage maximum up 30KV; LED voltage and current measure accuracy can reach to 0.2%; LED forward voltage resolution 1mV; reverse leakage current resolution 0.01μA. For LED lighting product, it electrostatic discharge immunity test shall be in accordance with GB / T 17626.2 / IEC61000-4-2 conducted. Contact discharge is the preferred test method for each metal parts (excluding terminals) accessible on the cabinet LED lighting products for 20 consecutive discharge, polarity 10 times each. It can be use air contact discharge test if can’t use contact discharge test. Indirect discharges shall be applied to the horizontal or vertical coupling board in accordance with GB / T17626.2 of. To ensure consistency and repeatability of test results, electrostatic discharge test specification must be 7 chapters are arranged according to GB / T17626.2. ESD61000-2 ESD simulator calibration data are as follows:

Calibration Data：

The Lighting Product EMC Problem and Testing Technology

2.3. Surge Test:

Lightning is very common climate phenomenon, according to statistics, there are over 40,000 of the world thunderstorm centers, eight million lightning strikes a day, which means lightning about 100 times every second occurrence. Lightning struck near the ground or nearby objects which caused strong electromagnetic field around it, then induces a high voltage and high current on the line. On the other hand, the surge in the power system is a very common phenomenon. As the main power supply switch, short-circuit and arc fault or ground network grounding systems and so on.

LED lighting products, especially for outdoor lighting products if without pay attention to lightning surge protection, it will seriously affect product reliability. A large area of LED lights in case of damage after thunderstorms common; According to quality supervision that there around have 60% LED lighting products can not meet lightning surges requirement. To assess the impact of LED lighting products, surge immunity performance shall be in accordance with IEC / EN61000-4-5 and GB / T 17625.5 requirements were surges testing. Test principle shown in Figure 5, the coupling network of common mode and differential mode test is different, differential mode test mean line – line test, the coupling capacitance is 18μF, it used to simulate the actual capacitance between the clouds and the earth; Common mode test mean line test – to earth test, the coupled network consist of capacitor and resistor network in series, the capacitor is 9μF and resistance is 10Ω.

The Lighting Product EMC Problem and Testing Technology

Lisun Electronic Shanghai office R & D designed and devolped SG61000-5 Surge Generator which applied big LCD touch screen technology and it has built-in Windows CE operate syste. This surge generator can test maximum 12KV voltage output, the user can set up common mode test or differential mode test by themselves. Moreover, this device can automatic record the EUT test parameters after finished test, these parameters can give designer some reference.

What are EMC tests?

What are EMC tests?

With the widespread use of electrical and electronic equipment, the problem of electromagnetic disturbance has also brought electromagnetic pollution.

EMC(Electro Magnetic Compatibility) refers to the ability of a device or system to operate within its electromagnetic environment without incurring unacceptable electromagnetic interference to any device in its environment.

EMC testing, one the one hand refers to the electromagnetic interference from the devices during normal operation in its environment cannot exceed a certain limit, on the other hand refers to the appliance has a degree of immunity to electromagnetic interference present in the environment. It divides broadly into emissions testing and susceptibility testing.

Electromagnetic Interference (EMI):

1. RE (Radiated Emission): Test unintentional release of electromagnetic energy from an electronic device or apparatus.
2. CE( Conducted Emission): Test the electromagnetic energy travelling along the power line, control line or signals lines.

EMC tests mainly contains as following:

1. Electrostatic discharge immunity test IEC61000-4-2
2. Radiated, radio-frequency, electromagnetic field immunity test IEC61000-4-3
3. Electrical fast transient/burst immunity IEC61000-4-4
4. Surge Immunity test IEC61000-4-5
5. Immunity to conducted disturbances, induced by radio-frequency fields IEC61000-4-6
6. Power frequency magnetic field immunity test IEC61000-4-8
7. Voltage dips, short interruptions and voltage variations immunity IEC61000-4-11
8. Ring Wave immunity IEC61000-4-12
9. Damped oscillatory wave immunity test IEC61000-4-18
10. Electro Magnetic Interference test system CRSPR11~12、CRSPR14~16、CRSPR20~22

Lisun can provide EMC test all solutions. Please contact us if you have needs

The Status of Integrating Sphere in China Market

IES LM-79-08 “Electrical and Photometric Measurement of Solid-State Lighting Products” as the exclusive international standard for measuring the total luminous flux, electrical power, luminous intensity distribution and correlated color temperature (CCT), color rendering index (CRI) and other colorimetric parameters of solid-state lighting products (SSL), it highlights the total luminous flux of SSL products should be measured with the integrating sphere system or goniophotometer. So the integrating sphere, as one of the main measuring instruments of SSL products, it can reduce and eliminate the measurement error caused by the difference of light shape, divergence angle and responsivity of different positions on the detector. Its design and manufacturing process is especially important and will directly affect the accuracy of test results.

Here we take a look at the current status of the production of integrating sphere technology in China market.

The Status of Integrating Sphere in China Market

Figure 1 The Old model Integrating Sphere

At present, there are still many suppliers in China using the old model integrating sphere. This kind of hemisphere is made of six steel sheets, and then using a clamp to combine the two hemispheres. The bottom is supported by an elastic adjustable foot to fix whole integrating sphere. However, there are many defects in this Splicing sphere, such as the structure is not strong, and it is easy to damaged and fell off during the long-distance transportation, and the ball is not round, which will definitely cause errors to the measurement results. We can see the difference in its shape when measuring with a standard round ruler, please refer to Figure 2:

The Status of Integrating Sphere in China Market

Figure 2 Using a standard round ruler to measure the old model sphere

Lisun developed a new type of integrating sphere (IS- *MA), its hemisphere is made of A Molding Technology which technical requirements are very high. So the test results are very accurate, and its appearance is elegant, also the roundness is very good, please see the following figures.

The Status of Integrating Sphere in China Market

Figure 3 Lisun New Design Integrating Sphere

The Status of Integrating Sphere in China Market

Figure 4 Using a standard round ruler to measure Lisun New Design Integrating Sphere

The new design integral sphere uses a fixed caster to replace the conventional fixed foot. And people can easily move the integrating sphere. Moreover, the sphere can be dismantled and assembled in half. The width of the hemisphere is about 1/2 of the whole sphere, which is very suitable for the transportation of spheres, especially for the small door size of offices or laboratories. In addition, this integrating sphere has equipped with a detachable test hold base, it can install different kinds of jigs according to the different types of lamp, which is very simple and convenient. The hold base can bear maximum weight 20 kg, It can be easy to install various lamps such as E27, E40, LED luminaires and so on. If you want to install other lamps, you just need to change the corresponding jigs. The hold base can be mounted on the bottom of the integrating sphere or mounted on the top of the integrating sphere. The position can be changed according to light sources. Please refer to the figure below.

The Status of Integrating Sphere in China Market

Now, let’s take a look at the comparison between these two kinds of integrating spheres.

The Status of Integrating Sphere in China Market

Old Model Sphere Lisun New Design Integrating Sphere

The Status of Integrating Sphere in China Market

Old Model Sphere Lisun New Design Integrating Sphere

The Status of Integrating Sphere in China Market

Old Model Sphere Lisun New Design Integrating Sphere

Please feel free to contact us if you need more info or quotations: Sales@Lisungroup.com