How to Test the LED Junction Temperature?

We know that the life of LED is closely related to its junction temperature. The key to prolonging its life is to reduce its junction temperature. And the key to reduce the junction temperature is to have a good heat sink that able to exhaust the heat generated by LED in time.

So, how to measure the junction temperature of LED?

Junction temperature seems to be a temperature measurement problem, but the junction temperature need to measure is in the internal of LED. Can’t we measure its temperature with a thermometer or a thermocouple into the PN junction. Of course, its shell temperature can be measured with thermocouple, and then its junction temperature can be calculated according to the thermal resistance Rjc (junction to the shell).

But things become more complicated after installing the radiator. Because usually LED is welded to the aluminum substrate, and the aluminum substrate is installed on the radiator. If you can only measure the temperature of the radiator shell, then it is necessary to know the value of a lot of thermal resistance to calculate the junction temperature.

Including Rjc (junction to case), Rcm (shell to the aluminum substrate, in fact, which also should include film printed version of the thermal resistance), Rms (aluminum substrate to the radiator), Rsa (heat sink to air), which only with one inaccurate data will affect the accuracy of the test. Figure 1 shows a schematic diagram of the LED to each thermal resistance of radiator. Where incorporates a lot of thermal resistance, making it more precision limited. That is to say, the accuracy of the junction temperature would be worse when inferred from the surface temperature of the radiator.

Figure-1-Schematic-diagram-of-LED-to-each-thermal-resistance-of-the-radiator

Fortunately, there is an indirect method of measuring temperature that is to measure the voltage. Then the junction temperature is relative to which voltage? And what is the relationship?

Firstly, we should talk about the characteristics of LED volt-ampere.
We know that the LED is a semiconductor diode, which has a volt-ampere characteristic same as all diodes. The volt ampere characteristic has a temperature characteristic that is when the temperature raises, the volt ampere characteristic left shifts. The Figure. 2. shows temperature characteristics of the LED’s volt ampere.

Figure-2-Temperature-characteristics-of-LED-volt-ampere

Assuming that the LED is powered by a Io constant current, when the voltage is T1, the voltage is V1. While the junction temperature rises to T2, the entire volt ampere characteristic is left shifted, the current Io is constant, the voltage changes to V2. The two voltage difference is removed by temperature, then the temperature coefficient can be obtained and shown by mV/oC. For ordinary silicon diodes, the temperature coefficient is about -2mV/oC.

But the LED is not made of silicon material, so its temperature coefficient should also be measured additionally. Fortunately, most of the LED manufacturers give its temperature coefficient in the data table. Take XLamp7090XR-E high power LED for example, its temperature coefficient is -4mV/oC, and 2 times larger than the ordinary silicon diode. The volt ampere characteristic temperature coefficient of Luxeon Rebel from a company of USA is -2 – 4mV/oC. As for LED Puri array (BXRA) of the USA, it gives more detailed data.
Figure-3-Decay-curves-of-LuxeonK2

However, the range of the data is too large, so that may loss the value of the using. Anyway, as long as the temperature coefficient of the LED is known, the LED junction temperature can be calculated from the forward voltage of the LED.

Lisun developed the T3 LED junction temperature thermal resistance electrical characteristic test, it can automatically record the changes of the parameters with time curve.

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, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.


Please feel free to contact us if you need any support.

Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096

How to Solve the Stroboscopic Problem of LED Lighting?

“Bright blind” in life is an exaggerated description of some impact incidents, but if it is used for the LED lighting industry, then it is the quality problems of LED lamp itself. And “strobe” is likely the initiator to lead to “blind”. Many people are not very clear about the concept of strobe, and even don’t care about its harm. Regarding the hazard of strobe, experts have given the conclusion.

A lot of LED lights on the market use the pulse power supply, their cost is relatively cheap, at the same time conducive to adjust the brightness, and also extend the working life of lamp. However, it is not a continuous light, but flicker in a very high speed, we can not see with naked eye. Only our brain and retina can detect the strobe. This kind of flicker may cause headaches, decreased attention and vision loss.

Energy Bureau staff told the media that the government should exert more attention to this problem, improve the laws and regulations, so that make unqualified products disappear from the market. At the same time, he stressed that the LED energy saving light technology will be better and better. Compared with the old light bulb, the consumption of LED lamp is only its 1/10, so this act may also plays an active significance to energy saving.

For there is strobe or not, users can use a simple method to distinguish. Firstly, turn on the light and then open mobile phone camera function, put the camera lens at a distance of 20cm from the lamp, then observe whether there is a dark stripe flicker in the phone camera screen. If there is flicker, then this lamp has strobe, if there is no flicker, then you can use this lamp rest assured.

Dated 14th December, 2012, the EU officially released the (EU) NO 1194/2012 rules implementing rules of the European Parliament and the EU Council Directive 2009/125/EC on the eco-design requirements of directional lights, LED lights and related equipment requirements. Compared with  European Parliament and Council Directive 2005/32/EC implementing rules for non-directional household lamps eco-design requirements which posted by the European Commission Regulation (EC) NO 244/2009 Regulations dated 18th March, 2009, the new rules have complete mandatory and eco-design requirements.

For LED manufacturers, they can only use professional testing equipment to detect the stroboscopic problem of LED. The LSRF-1 Lamp Start, Run-up time and Flicker Test from Lisun Electronic (Shanghai) office is integrated equipment which can test Lamp Start, Run-up Time and Flicker. To meet EU ErP requirements, IEC60969 Self-ballasted Lamps for General Lighting Services Performance requirements and Energy Star about Lamp Start, Run-up Time and Flicker Test. LISUN developed ErP test system, the system hardware consists of PH3000 and LSP-500VAC; the software consists of LST-3000 Lamp Start and Run-up Time Test and FLK-3000 Lamp Flick Test.

Lisun Electronic (Shanghai) office is committed to the development and after-sales maintenance of lighting instrument, EMI / EMC test system and Electrical Safety Tester in the domestic and global market. The full range of products of Lisun are in strict accordance with the quality management and control of ISO9001:2008 requirements for R & D and production; Lisun is also the member of global lighting CIE association, all products are according to CIE requirements; in addition, all products of Lisun are certified by CE and get the qualification of the EU.

How to predict the life of LED?

In general, LED can be used for more than 50000 hours, and some manufacturers are promoting their LED to operate for about 100000 hours. The main problem in this area is that LED is not simply no longer operational. Its rated service life can not be calculated by traditional lamps and lanterns. In fact, when testing the life of LED, no one will be waiting for it to stop functioning. However, there are other ways to measure the life of LED. The reason why LED is durable is that it does not produce filament fuses. LED will not stop operation directly, but it will gradually deteriorate over time. It is predicted that high quality LED can maintain more than 60% of the initial lamp brightness after 50000 hours of continuous operation. Assuming that LED has reached its rated service life, it may still be luminous, but the light is very weak.

Without considering the power and driving failures, the life span of LED is characterized by its decay, that is, the longer the time is, the more darker the brightness will be, until finally extinguished. The time of decay of 30% is usually defined as its life. So can the life of LED be predicted?

 1. Light failure of LED
Most white LED is obtained by irradiating yellow phosphor with blue LED. There are two main reasons for LED fading. One is the decay of Blu ray LED itself, and the blue light LED has far more light decay than red light, yellow light and green light LED. Another is the decay of phosphor, and the attenuation of phosphor at high temperature is very serious.

The decay of LED is related to its junction temperature. The so-called junction temperature is the temperature of the semiconductor pn junction. The higher the junction temperature is, the earlier the decay occurs, that is, the shorter the life. If the junction temperature is 105 degrees, the lifetime of the brightness to 70% is only more than 10000 hours, 95 degrees will be 20 thousand hours, and the junction temperature is reduced to 75 degrees, the life will be 50 thousand hours, and 65 degrees can be extended to 90 thousand hours. So the key to prolonging life is to reduce junction temperature. But these data are only suitable for Cree’s LED. It’s not suitable for other companies’ LED. When the junction temperature is increased from 115 to 135, the life will be reduced from 50000 hours to 20000 hours.

2. How can we prolong the life of LED?
The key to prolonging its life is to reduce its junction temperature. The key to lowering the junction temperature is to have good radiator. It is able to send out the heat generated by LED in time.

3. How to predict the life of this lamp.
Judging from the junction temperature, life expectancy should be very simple. You can know that the life of LED can reach 20 thousand hours at the temperature of 95 knots. However, this method for indoor LED lamps and lanterns has certain credibility, if applied to outdoor LED lamps, especially high power LED street lamps, there are many uncertainties. The biggest problem is that the heat dissipation efficiency of the LED Street radiators decreases with time. This is due to the accumulation of dust and bird droppings, resulting in reduced heat dissipation efficiency. Also because there is a strong ultraviolet light outside, it will also reduce the life of LED. Ultraviolet radiation plays an important role in the aging of encapsulated epoxy resin. If silica gel is used, it can be improved. Ultraviolet radiation also has some bad effects on the aging of phosphors, but it is not very serious.

The LEDLM-80PL LED luminous flux maintenance rate and aging life testing system, launched by Shanghai power Shantou, are designed and manufactured according to the CIE and IEC standards such as IES-LM-80, IES-LM-82, TM-21, GB2312-80 and so on. It can record the curve of luminous flux with time and the curve of color parameter changing with time. The life time of LED is calculated by testing the data of light decay for a short time.

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, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.


Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096

How to Measure the High Frequency Fluorescent Lamp

High frequency fluorescent lamp came out in 1990. Fine tube, small current and high power is the distinct features. Because of the above design structure, high frequency current working, electronic ballast with low power consumption, the work system of this high frequency fluorescent lamp is superior to the traditional lamp on the aspect of lighting effect and photometric.

How to measure the characters of the fluorescent lamp in high frequency condition? How to verify the match relationship of the tube and ballast? These problems always trouble the fluorescent tubes manufacture enterprise and the third lab service company. Lisun Group supplies the following two solutions: IEC Standard Test Method and High Frequency Constant Current Equivalent Test Method.

1. IEC Standard Test Method:
Double end fluorescent lamp adopts the IEC 60081 (GB/T10682) and the single-ended fluorescent lamp adopts the IEC 60901 (GB/T17262), where in the standard of electricity parameters as in Fig 1. As we know the testing correctness of the photo & color parameters are based on the fact that the reference ballast, power and instrument in the detection circuit all comply with standards. If the reference ballast, power and instrument can’t meet the standard that means it can not supply the tube with standard working conditions. Then, not only the tested electricity parameter but also the photo & color parameters will deviate from the actual value obviously.

Fig 1 Preheating Method of Cathode High Frequency Fluorescent Lamp

Fig 1 does the high frequency tube test based on IEC Standard which required the High Frequency Power Source, Adjustable Reference Ballast and Lamp Preheat Assistant Source.

●High Frequency Power Supply (HFP-800): output power is 20～26kHz, the frequency should be kept in the range of ±2％ at working. Output power is 0～580V.
●Adjustable Resistance Ballast (RB-3): impedance values of high frequency reference ballast which used by any high frequency lamp with regard to GB/T10682 (IEC 60081) and GB/T17262 (IEC60901), RB-3 conforms to the requirement of IEC60929.
●Lamp Preheat Assistant Source | Auxiliary Power Supply (LPS-3): Preheating method of cathode during the high frequency fluorescent lamp starting.
The above IEC Standard Test System is the necessary instrument not only to measure the photo & electricity parameters according to the standard of IEC 60081 and IEC 60901, but also to test the lumen and color parameters according to the standard of IEC 60929 (GB/T15144). Any national lighting electrical test centers must adopt the above test system if they need to do High frequency lamp such as T5 tube.

2. High Frequency Constant Current Equivalent Test Method:
Even though, the above Standard Test System can totally conform to the requirement of measuring the high frequency fluorescent lamp by IEC standard, due to the high price of this system, the small third lab service company and the most of manufactory company can’t cover the high cost, Lisun Group developed HCS-109A Adjustable High Frequency Reference Ballast which is an equivalent test method in comparison with IEC method. The typical schematic is shown as Fig 2, high frequency constant current source provides a continuously adjustable output current of 100mA ~ 500mA.

Fig 2 High Frequency Constant Current Equivalent Test Method

When connecting the circuit to turn on the lights, high frequency constant current source will deliver high-voltage pulse to start the lamp, the output frequency of high frequency constant current source is in 20～26kHz. The obvious shortage of equivalent method is due to the high constant current source output internal impedance. The large internal impedance of high frequency constant current source will cover the departure of tested lamp with respect to standard electrical parameters. It will take about 5%~ 30% tolerances when using LPCE-1 Fig 3 to test the photo, color and electricity parameters.

The above HCS-105A equipped with LPCE-2 High Precision Spectroradiometer Integrating Sphere System can test CCT, CRI, Spectrum, Lumen and electricity parameters for high frequency fluorescent lamp T5.
LPCE 2(LMS 9000) Spectrophotometer & Integrating Sphere Test System

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, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber,  Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.


Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096

How to measuring LED lamp start, run up time and flicker effectively?

Due to the LED solid-state lighting products have good luminous efficiency, long life and high reliability unique characteristics, so it’s became more popular by markets and customers. But at the same time, the LED solid lighting have fast response characteristics, it haven’t thermal inertia and afterglow effects, like traditional lamps, so it have big influence by current fluctuations, the current fluctuations affect the luminous flux output directly, the lighting flashing is the external expression of luminous flux change, that caused more and more people focus on lighting flashing issue. Dated 14th December, 2012, the EU officially released the (EU) NO 1194/2012 rules <Implementing rules of the European Parliament and the EU Council Directive 2009/125/EC on the eco-design requirements of directional lights, LED lights and related equipment requirements>.Compared with <European Parliament and Council Directive 2005/32/EC implementing rules for non-directional household lamps eco-design requirements> which posted by the European Commission Regulation (EC) NO 244/2009 Regulations dated 18th March, 2009, the new rules have complete mandatory and eco-design requirements. Start and Run-up time as the two indicators functional requirements in the industry has been more emphasis by manufacturers.

We just talked about the LED solid lighting product’s flicker effect, many people have no idea about this. The light source flashing is directly expression of luminous flux fluctuation, the light source is driving by AC current and pulsed DC current, luminous flux, illuminance or brightness change accordingly with the current amplitude of cyclical change. Normally, according to human eyes feeling, the flicker divided into Visiable Flicker and Invisible Flicker. When the frequency more than 100Hz, the human eyes can’t feeling the flicker, but it will cause eyestrain, headache etc, this is the flash effect, generally agreed that the flicker effect exists within 500Hz. For this issue, America Energy Star(ENERGY STAR lamps V1.0 draft 4 In the dimming performance requirements specified in the blink Conditions to be fulfilled, use all tools). As below figure:

Light source flashing allowed range:
1、Frequency less than 100Hz;
2、Within 120Hz-800Hz frequency range, the F1<0.001 X frequency;
3、Frequency more than 800Hz, F1 have no requirements;
4、Frequency is uncertain, PF<30%;

Besides, the CFL lamp output frequency range should at 20-30KHz, or more than 40KHz.

The nature of light source flicker is luminous flux output fluctuations. When measuring light fluctuates with time change, not only the brightness curve can be tested, but also can test luminous flux curve or illumination curve which are under the same conditions. ENERGY STAR（V1.0）make the rules to measuring flicker’s requirements:

1、Power and instrumentation are need meet the requirements of LM-79-08;
2、Multi-channel oscilloscope with memory function, necessary need to add attenuation probe. The sampling rate is more than 2kHz, the sampling time is more than 100ms;
3、Photo detector V(入) Correction, and need meet the requirements of the corresponding time;
4、For the absolute value of the metering(absolute photometry): Need use integrating sphere when measuring of the absolute value; For relative value metering(relative photometry): To ensure that the detector is capable of measuring the relative light output, and only receives light from the light source to be measured;

Before measuring, the CFL lamps need light on 100 hours at least and it’s need preheat before testing. LED lamp needn’t lighting on, the environmental temperature range should at 25+/-5 degrees.

To meet EU ErP rules and Energy Star requirements, Lisun developed LSRF-2 Lamp Start, Run-up time and Flicker Test System. The hardware of this system included PH3000 Transient Photometer, LSP-500VAC Programmable AC Power Source Meter, IS-MA series Integrating Sphere, DC3005 DC Power Source and SLS series Standard Lamp; the software of this system included LST-3000 Lamp Start and Run-up Time Test and FLK-3000 Lamp Flick Test. PH3000 Transient Photometer is developed base on rapid sampling techniques, it’s fully meet EU and Energy Star relevant requirements. Combined with computer, it can measuring and record the fast change luminous flux waveform and others parameters. PH3000 applied with 12 Bytes, the maximum sampling rate of 10M Hz high-speed A / D. The PH3000 also can used as common illuminometer which can be widely used in light flux, brightness, illumination, etc. photometric detection and measurement. LSP-500VAC Programmable AC Sine Wave Power Source is a high-power, low pure sine wave distortion, high stability, integrated power supply source table, it’s especially suitable for as test power supply of electronic ballasts, energy saving lamps and other small power household appliances. And this system also included IS-1.5MA Integrating Sphere, DC3005 DC Power Source and SLS-50W Standard Light Source.

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, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.


Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096

How To Build The Darkroom For Goniophotometer?

Goniophotometer is mainly used for light intensity performance measurement of luminaries and light source, which is the photometry value in different directions in space and color distribution. Goniophotometer should run in dark room, and what are the requirements for the test environment?

The size requirements for dark room: for example, such as LISUN LSG-5000 LM-79 Type C Mirror Goniophotometer System. According to CIE requirement, dark room consists of 2 parts, the recommended size of the dark room for Goniometric Rotating Console is W5.0m*L5.0m*H5.9m;  the recommended size of the dark room for Photometric Light Path is W1.5m*H1.5m*L(15m – 30m). According to the requirements of CIE, the recommended distance between lamp and photo detector is 6 times than the diameter of lamp. The recommended size of operating room is no less than W3m*L3m. LISUN GROUP engineer dept will submit the Lab Design support documents according to the customer’s real lab size after the formal purchase order was confirmed.

Requirements of eliminating the stray light: the photodetector can only receive the light reflected by the rotating mirror in the LSG-5000 system. The light given off directly by the luminaries and reflected by the wall and floor is warded off by the light fence. Internal surface of the dark room and dark path together with the surface of the light fence should be painted unpolished black or be covered by black cloth and black carpet.

Temperature of the Environment: Because of the thermal performance of LED, the photometric value and electronic performance of SSL products are sensitive to the change of temperature and air movement. Temperature around the lamp or luminaries must be 25℃±1℃ during the test. The temperature should be measured in the distance that is no more than 1m, and measurement height should be the same with the SSL product. Temperature sensor should avoid the direct optical radiation of SSL product and other light source. Therefore, you should place an air conditioner in the dark room to control the temperature around the lamp to reach the temperature requirement of CIE. If the measurement is not doing under the recommended temperature, this is a non-standard condition, which should be remarked in the test report.

Requirements of Airflow: Airflow may be induced by natural aeration, air conditioner or movement of the luminaries in the goniophotometer, but the speed of the airflow couldn’t exceed 0.2m/s. The airflow of the tested lamp surface may greatly change the electric value and photometric value. The testing personnel must not enter the dark room during the test.

Vibration and shock: When the lamp is in lighting, the vibration couldn’t exceed 10m/s2(4～3000Hz), or the moving scope of the lamp couldn’t exceed 30mm (at most 4Hz).

Smoke, Dust and Moisture: The test environment must free from smoke, dust or moisture. At the same time, even not during the measurement, smoke, dust or moisture will also influence the reflectance of the reflecting mirror and induce more stray light. So, the test room must be kept clean, no smoke and dry. The humidity should be less than 60% RH.

LISUN has many different types of goniophotometers. Pleae click to view the different darkrooms for different goniophotometers.

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, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.

Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096

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