LED Luminescent Spectrum

LED Luminescent Spectrum

 

Spectrum is the relative distribution of wavelength and light intensity. The spectrum of LED is generally monochromatic LED, such as blue LED with a peak wavelength of 470nm, with shorter peak wavelength ultraviolet area and with longer peak wavelength green areas as the determination limitation of light intensity.

And the spectrum of incandescent lamp, its luminous intensity is widely distributed in the blue area 400nm to 700nm near infrared field, in the field of ultraviolet and infrared can also observe the luminous intensity. As for Fluorescent lamp, the part of combination usage's phosphor light wavelength is the peak of the spectrum.

Compared with the ordinary red, green and blue LED spectral peak, the white LED spectrum is different. For example, there are two luminous intensity peaks in the area of blue and yellow, or in the blue field, yellow and red fields, there are three peaks, and even more. This is because the white LED white light is a combination of multiple wavelengths of light. For instance, a combination of blue and yellow phosphor LED, the peak is in the blue and yellow field. In addition, based on the blue LED luminous intensity of peak is sharp, and the phosphor peak is relatively flat.

When the LED is used in the liquid crystal panel back light, the most ideal situation is that the spectrum of LED appears luminous intensity peaks in three areas of red, green and blue. This is because the LED light will eventually be output to the outside through the liquid crystal panel of the color filter (red, green, blue).

Getting three luminous intensity peaks, using red, green and blue three kinds of LED, and through improved phosphor material, use method of obtaining three peak of white LED

 

The lighting of blue LED and YAG phosphor, blue LED and ZnSe single crystal plate, UV LED and RGB phosphors and white LED light spectra and fluorescence light and natural light. Although they are white, but the emission spectrum is different, on the other hand, when LED is used for ordinary lighting apparatus, the white LED will be more popular where the spectrum is widely distributed in the visual field. The reason is that close to the natural light, when the spectrum of the sun's rays illuminates the object, the color of the object is close to the nature of the exposure to light

 

LED Luminescent Spectrum

LED Luminescent Spectrum

 

Spectrum is the relative distribution of wavelength and light intensity. The spectrum of LED is generally monochromatic LED, such as blue LED with a peak wavelength of 470nm, with shorter peak wavelength ultraviolet area and with longer peak wavelength green areas as the determination limitation of light intensity.

And the spectrum of incandescent lamp, its luminous intensity is widely distributed in the blue area 400nm to 700nm near infrared field, in the field of ultraviolet and infrared can also observe the luminous intensity. As for Fluorescent lamp, the part of combination usage's phosphor light wavelength is the peak of the spectrum.

Compared with the ordinary red, green and blue LED spectral peak, the white LED spectrum is different. For example, there are two luminous intensity peaks in the area of blue and yellow, or in the blue field, yellow and red fields, there are three peaks, and even more. This is because the white LED white light is a combination of multiple wavelengths of light. For instance, a combination of blue and yellow phosphor LED, the peak is in the blue and yellow field. In addition, based on the blue LED luminous intensity of peak is sharp, and the phosphor peak is relatively flat.

When the LED is used in the liquid crystal panel back light, the most ideal situation is that the spectrum of LED appears luminous intensity peaks in three areas of red, green and blue. This is because the LED light will eventually be output to the outside through the liquid crystal panel of the color filter (red, green, blue).

Getting three luminous intensity peaks, using red, green and blue three kinds of LED, and through improved phosphor material, use method of obtaining three peak of white LED

 

The lighting of blue LED and YAG phosphor, blue LED and ZnSe single crystal plate, UV LED and RGB phosphors and white LED light spectra and fluorescence light and natural light. Although they are white, but the emission spectrum is different, on the other hand, when LED is used for ordinary lighting apparatus, the white LED will be more popular where the spectrum is widely distributed in the visual field. The reason is that close to the natural light, when the spectrum of the sun's rays illuminates the object, the color of the object is close to the nature of the exposure to light

 

Integrating Sphere Development

Integrating Sphere Development

 

Integrating Sphere is used for flux measurement, which can make test result more reliable. Integrating Sphere can reduce the measurement error caused by the shape of light, divergence angle and responsiveness difference in different location on detector.

Let us learn more details about the development of Integrating Sphere manufacture technology.

Picture 1:Old Model Integrating Sphere

Picture 1 is old model Integrating Sphere. The hemisphere manufacturing technology of this Integrating Sphere is surrounded by six iron sheets via angle iron, and then two hemispheres are connected by fixture. The bottom adopts adjustable foot to support and fix the whole sphere.

Picture 2 Improved Model Integrating Sphere

Picture 2 is the improved model integrating sphere. This integrating sphere specification makes no difference with old model. But the critical technologies are that hemisphere is disposable stamping by mould. Technology requirements are very high. Measurement data error is quite small. Overall appearance is succinct.

Picture 3  Latest Integrating Sphere

The overall structure of latest Integrating Sphere is simple and beautiful with powerful function. This sphere can be assembled in half. The hemisphere width can be controlled at about 1/2 of the entire width of the sphere after disassembly, which is convenient to transport, especially for small office or laboratory door. The disassembly and installation of this model Integrating Sphere just needs to twist six screws in bracket.

 

 

In addition, Lisun is the first to achieve the integration of Integrating Sphere and Cabinet. We can put spectroradiometer, digital power meter and power source in the cabinet, which greatly facilitate the installation of wires.

 

Jacky Installation training in Poland

Jacky Installation training in Poland

 

This Polish customer purchased a High & Low Temperature and Humidity Chamber, IK level Tester and Dustproof Testing Machine from LISUN this time. They are a relatively large lighting manufacturer. We arranged engineer to do installation and training for them when confirm that the customer received the goods. The customer is very satisfied with our service, and indicating that we are the most responsible Chinese manufacturer they have met and will continue cooperating with us in the future.

 

We share some photos here:

[caption id="attachment_8795" align="alignnone" width="800"] Figure 1: Jacky (the right 2) with the client's photo[/caption]

 

[caption id="attachment_8797" align="alignnone" width="800"] Figure 2: The customer is installing the device[/caption]

[caption id="attachment_8798" align="alignnone" width="800"] Figure 3: Customer are familiar with the operation[/caption]

[caption id="attachment_8799" align="alignnone" width="800"] Figure 4: Customer is practicing the operation[/caption]

Introduction of EMC Testing

Introduction of EMC Testing

 

EMC (Electro-Magnetic Compatibility) refers to the ability of a device or system to function in its electromagnetic environment and does not constitute an unacceptable electromagnetic disturbance to anything in that environment. EMC is an important indicator of product quality.

 

EMC tests include:

 

• EMI (Electro-Magnetic Interference): Electromagnetic disturbance testing

The purpose of this test is to detect the effects of electromagnetic radiation generated by electrical products on the human body, the public grid, and other electrical appliances that are working properly.

 

(2) EMS(Electro-Magnetic Susceptibility): Electromagnetic Immunity Test

The purpose of this test is to detect electrical products whether can work stable and unaffected in the electromagnetic environment.

 

EMI tests include:

 

(1) Radiated disturbance test (RE) - Test standard: EN55022

(2) Conducted disturbance test (CE) - Test standard: EN55022

(3) Harmonic current test (Harmonic) - Test standard: EN 61000-3-2

(4) Voltage change and flicker test (Flicker) - Test standard: EN 61000-3-3

 

EMS tests include:

 

(1) Electrostatic discharge immunity test (ESD) - Test standard: EN61000-4-2

(2) Radio frequency electromagnetic field radiation immunity test (RS) - Test standard: EN61000-4-3

(3) Conducted disturbance immunity test (CS) for RF field sensing - Test standard: EN61000-4-6

(4) Electrical fast transient immunity test (EFT) - Test standard: EN61000-4-4

(5) Surge immunity test (SURGE) - Test standard: EN61000-4-5

(6) Voltage dips, short interruptions and voltage variations Immunity test (DIP) - Test standard: EN61000-4-11

(7) Power frequency magnetic field immunity test (PFMF) - Test standard: EN61000-4-8

 

 

Brief introduction of CE certificates

 

In recent years, the CE marks are more and more widely used in the market of European economic area (Member states of the European Union and the European Free Trade association, except Switzerland). More customs of different countries set out the requirements of CE certification for imported products. Exporter will be in trouble as well as unnecessary loss if their shipping goods don't have CE certified label. So, what is the importance of CE certification? What are the forms of CE certification so far? And what are the risks of products that has not been certified by CE?

 

1. The importance of CE certification

 

The CE mark on the packaging indicates that it meets the requirements of a series of European directives such as safety, sanitation, environmental protection and consumer protection. In the past, EC(European

Community)countries require differently for import and sale of products. The goods which are produced according to national standards may not be on the market. As part of the efforts to eliminate trade barriers, CE came into being at that time. Therefore, CE can be understood as CONFORMITY WITH EUROPEAN (DEMAND) (in Europe).

 

The meaning of the CE mark is as the following: Using CE acronym as symbol shows products which affix the CE mark meet the main requirements of relevant provisions of the European Directive (Essential Requirements),and it's also used to verify that the products have passed the conformity assessment procedure or the manufacturer's declaration of conformity. The CE mark is truly as a passport for the products being allowed to enter the European market. For industrial products which must affix CE mark according to relevant instructions, they can be in the market without CE mark, or they must be taken back if they don't meet safety requirements but with CE mark and in the market. For industrial products which must affix CE mark according to relevant instructions, they can be in the market without CE mark, or they must be taken back if they don't meet safety requirements but with CE mark and in the market. Moreover, the products will be restricted and prohibited from entering the EU market or forced to withdraw from the market if they violate CE mark instructions in European Directive.

 

 

The most important function of CE is to ensure the safety of the products and ensure the products work well under the conditions of the European union. CE mark like a tickets for products entering the European market, if products are not certified by CE, it's most likely to be seized of by European customs and cause exporters’ unnecessary losses.

 

2. Advantages of CE certification

The import of CE certified electronic instruments and equipment can effectively avoid the following risks:

• The risk of being detained and investigated by the customs;


• The risk of being investigated and dealt with by the market supervision institution;


• The risk of being charged by competitor for other purpose;

 

The import of CE certified electronic instruments and equipment has the following advantages:

• The import of CE certified equipment can avoid a lot of trouble in the import and export because the laws, regulations as well as standards of EU are not only numerous, but also very complex;


• It can enhance the reliability of their product performance by using CE certified equipment for testing or production. It also can effectively prevent the emergence of irresponsible allegations;


• The CE certificate of the institution designated by European Union will be the important evidence with legal effect when you are facing to litigation;

 

For electronic equipment and testing equipment, there is a very important parameter " EMC test" when the products are doing CE certification. Because the power grid frequency, voltage in Europe countries are differen from China Mainland, these products are likely to be damaged in the course of use if not detected. At the same time, there are many interference factors such as pulse group, lightning surge interference, voltage dip and so on. If there is no CE certification, the equipment is likely to be damaged and can't be used normally.

 

3. Current forms of CE certification in China mainland

At present, there are three kinds of domestic CE certification as following:

 

A：Only certified certificate, no test report:

This type of certificate is almost invalid and cannot be queried on the appropriate website. Products with this certification mark can't be recognized as ticket to the European market. Products with this kind of certificate is equivalent to the product without CE mark, and they should be detained or even returned.

B: Certificate of compliance / Certificate of compliance, with test report:

       This type of certificate is issued as a statement of conformity by the third party Agency (agency or test certification body). The test reports and other technical documents TCF should be enclosed by this kind of certificate. At the same time, enterprises also have to sign the<declaration of conformity>. This type of certification report is only recognized in mainland China. Although there are the test report and related certificates according to the requirement, the relevant information can only be checked on the detection of the company's own website. But many such testing company themself do not comply with EU certification requirements. The certificate is only applicable to the manufacturer for product quality self inspection, there is also a greater risk of being detained by the customs ana cause fines and delivery delays. This will affect the normal use of products. This kind f certificate is shown in the following figure :

[caption id="attachment_8761" align="alignnone" width="800"] Brief introduction of CE certificates[/caption]

 

 

 

 

 

C: EC Attestation of conformity < EU standard compliance certificate >

This type of certificate is issued by the EU notified body (Notified Body known as NB). According to EU regulations, only the NB are eligible to issue EC Type CE Declaration.

This type of certificate and test report are issued by testing organization certified by EU. The products finish the complete testing during the certification process and has a complete test report. Meanwhile, certificate No. can be found in the appropriate Website. Only these electronic equipment which has finished the testing and certification  can be exported to EU and can get CE label. All of Lisun series devices do CE certification in such bodies certified by European Union, and has integrated <EU standard compliance certificate> and corresponding test report. Certificate template is shown in the following figure:

[caption id="attachment_8762" align="alignnone" width="800"] Brief introduction of CE certificates[/caption]

 

 

 

 

Lisun is lead in designing and producing high quality, high precision, high performance products to Europe and customers from all over the world. Lisun applied the first CE certification at the beginning of entering the European market and provide long-term excellent quality services for European customers. When the CE certificate expires, Lisun immediately contact the top certification bodies to do

 

CE certified and testing for all products, and quickly get the CE certificates and reports that meet EU requirements. CE marks are added on all packages of the devices.

Advantages and disadvantages for total flux test of Integrating Sphere System and Goniophotometer

Advantages and disadvantages for total flux test of Integrating Sphere System and Goniophotometer

 

According to IESNA-LM-79-80, the total luminous flux (lumen) of SSL products shall be measured with an integrating sphere system or a goniophotometer. The method may be chosen depending on what other measurement quantities (color, intensity distribution) need to be measured, the size of SSL products, and other requirements.

 

The integrating sphere system is suited for total luminous flux and color measurement of integrated LED lamps and relatively small-size LED luminaires. The integrating sphere system has the advantage of fast measurement and does not require a dark room. Air movement is minimized and temperature within the sphere is not subject to the fluctuations potentially present in a temperature-controlled room. It should be noted that the heat from the SSL product mounted in or on the integrating sphere may accumulate to increase the ambient temperature of the product under test. Two types of integrating sphere systems are used, one employing a V(l)-corrected photometer head, and another employing a spectroradiometer as the detector. Spectral mismatch errors occur with the first method due to the deviation of the relative spectral responsivity of the integrating sphere photometer from the V(l), while there are theoretically no spectral mismatch errors with the second method.

 

The spectroradiometer method is preferred for measurement of SSL products because spectral mismatch errors with the photometer head tend to be significant for LED emissions and correction is not trivial, requiring knowledge of the system spectral responsivity as well as the spectrum of the device under test. In addition, with the spectroradiometer method, color quantities can be measured at the same time as total luminous flux.

 

Goniophotometers provide measurement of luminous intensity distribution as well as total luminous flux. Goniophotometers can measure total luminous flux of SSL products of relatively large size (corresponding

to dimensions of traditional fluorescent lamp luminaires) while they can measure small SSL products as well. A goniophotometer is installed in a dark room, normally temperature-controlled, and is not subject to heat accumulation from a source being measured. Care must be taken, however, for drafts from ventilation that might affect measurement of SSL products that are sensitive to temperature. Measurements with a goniophotometer are

time-consuming compared to a sphere photometer. Goniophotometers using broadband photopic detectors are susceptible to the spectral mismatch errors noted above. In fact, correction for spectral mismatch can be more difficult if there is significant variation in color with angle.

 

Generally, when integrating sphere system and Goniophotometer test light source, the difference of data is not large. If test luminaries, the test result of Goniophotometer should be as the criterion, of course, it should ensure that the calibration of Goniophotometer accurate. According to formal test requirements, integrating sphere system is to test for light source, Goniophototmeter is to test for luminaires.

 

Lisun LSG-2000 is an automatic light distribution intensity 3D curve testing system. The measuring distance is from 5m to 30m. It can measure all types of lighting sources, LED or HID luminaires such as indoor and ourdoor luminaires, roadway luminaires, street lamps, flood lights and other kinds of luminaires.

 

Lisun LSG-2000 Moving Mirror Goniophotometer System is widely applied to Luminaries manufacturing enterprise and lab, such as Sharp Electronics in Memphis TN(USA), CS TECH MEXICO, S.A. DE C.V. (Mexico), DORADO Praha s.r.o. (Czech) etc. The reason why Lisun can win some many customers is because we always practice the motto of right products, right price and right service. Lisun will continue feedback good quality products and superior service in the feature.