Comprehensive Analysis Of LED Spotlight Part 1

- Mar 13, 2017-

The rapid development of LED technology, and constantly improve the light efficiency, LED lighting technology is also in rapid development. At present, LED spotlight is almost to replace the traditional halogen lamp. Compared with the traditional lamp, LED lamp has significant advantages in energy saving and long life. With the decrease of LED lamp cost, application of LED spotlight gradually began to spread. The "comprehensive analysis" LED reflectoscope lamp is divided into two parts, the first part from LED spotlights the technical requirements, types and specifications of the common structure for everyone to talk.

 

(1) For LED lighting technology

The LED lamp at the present stage, mainly to replace the traditional halogen lamp, the relevant safety requirements mostly refer to the traditional lighting requirements, and according to the characteristics of the LED lamp, formed a set of safety certification standards. At present, in the international spotlight LED certification, mainly in Europe and North America CE UL certification, in Chinese for voluntary certification (CQC).

 

In the CE certification contains two aspects of LVD and EMC, where LVD is in accordance with the EN60968 standard implementation (will upgrade IEC 62560); EMC in accordance with EN55015, EN61547, EN61000-3-2 and EN61000-3-3 standards. In addition, LED lights usually require an additional reference to IEC 62471, to carry out bio safety testing. In North America, UL security and FCC electromagnetic compatibility certification is usually required. UL execution standards for UL1993, UL8750 and UL1310; FCC standard execution for FCC PART15 Subpart B. In Chinese, for LED lighting is the use of voluntary certification (CQC), the implementation of standards for GB24906-2010 (safety) and GB 17743-2007 (electromagnetic compatibility).

 

In addition, the performance of LED lamp, there are also many standards. TheUnited Stateshas the energy star (ENERGY STAR) has the relevant requirements;Chinahas energy-saving certification requirements, the implementation of standards for CQC 3129-2010. These requirements are for the LED lamp, color temperature, color rendering index, luminous flux, luminous efficiency and luminous maintenance rate, life span, center intensity, nominal power, power factor, product identification was provided.

 

The life expectancy of many electronic products is judged by the broken, but LED is a very long life light source, can be used for a long time will not be bad. But it will output luminous flux decay with time, so the industry usually decline to 70% of the time required to define the LED life of the light source, namely L70. With the development of technology, more and more LED slow decay, to complete the test light to 70% of the time to do. Because the electronic product life exponentially, so LED usually do a short time aging, decay by sampling data, then the exponential function to calculate the decay to 70% of the time, the calculation formula as shown above.

 

LED lamp specifications and types

 

The common LED lamp specifications and types

 

Usually 6000 hours on LED aging test luminous maintenance rate (Lumen Maintains LM), according to the index law, if 6000 hours after LM > 91.8%, can say that 25000 hours of life, if LM > 94.1% can be claimed 35000 hours of life, but life is 6 times the estimated time does not exceed the test time.

 1.jpg

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LED lighting angle, with 50% beam peak intensity angle to define. Picture 2 is a LED lamp polar light distribution curve, we can see that the light intensity of 50% corresponding angles are + 20 degrees, so the light angle is 40 degrees.

 

(2) Specifications and common types of LED spotlight

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At this stage the main LED lamp to replace the traditional halogen lamp, so the size is according to the standard of IEC 60630, according to IEC 60061-1 standard lamp. According to the traditional lamp, LED lamp is mainly MR16, PAR16, PAR20, PAR30, PAR38 of the several. The MR16 usually adopts GU5.3 lamp; PAR16 mainly adopts GU10, E26 (America) /E27 (European andChina), E14 lamp; PAR20/PA30/PAR38 mainly adopts E26, E27 lamp.

 

(3) Analysis of the Structure of Common LED Spotlight

LED spotlights are currently self ballasted type, namely LED drive power all installed in the light body, direct electrical connection can be used.

4.jpg

If the lamp dismantling map of Picture 4 you can see, LED spotlights the main optical devices present (lens and reflector), LED light source, a radiator, a driving power supply, this lamp consists of several parts. But the LED lamp manufacturers, due to the use of materials, technology and LED package in different ways, the spotlight in the design and processing will have some differences.

 

1. LED light source and optical device

 

At present, LED spotlights mainly adopts a plurality of high-power LED integrated package and LED production, as shown in figure 5.

5.jpg

 

The use of multiple high-power LED way, usually requires a circuit board to do the electrical connection LED. The circuit board is mostly made of aluminum substrate (MCPCB); for some designs are also made of glass fiber board (FR-4), but the need to design a special heat sink. Then with screws or adhesive fixed on the lamp shell radiator. A plurality of high power LED production of the lamp, is usually used for independent lens light distribution on each LED, and then combined into a lens flare.

 

The integrated package produced by the LED lamp, circuit board is not needed, can directly drive power output line connected to the LED lamp. Is the same with a screw or adhesive fixed on the lamp shell radiator. Two times the optical spot, usually using a lens or reflector of light, lens and reflector height is high, small angle light distribution is difficult.

 

In addition, for a very smooth lamp, light design two times with the most of the multiple optical devices combination to complete the whole lamp, as shown in picture 6.

6.JPG

 

2. LED Drive

 

At present, LED spotlights are mostly self ballasted lamp with built-in power supply type. The built-in LED driver is mainly realized by switching power supply. Isolated power supply for the primary and secondary forms of electrical isolation, in lamp design, only need to supply the primary and the shell or other body part can fully contact to avoid electric shock, while the secondary is usually safe voltage, can do a simple door. This kind of power supply is relatively safe and reliable, but requires a large space, the conversion efficiency is also low. Because of the isolation between the primary and the other, the non isolated power supply needs more strict protection isolation in the structure.

7.JPG

 

In addition to switching power supply, there are a variety of other LED drive, but its security and reliability are low, the need for structural design to do more efforts to meet the relevant safety requirements. In addition, due to the power built-in components usually have a high temperature, the LED lamp will directly affect the service life and stability. Therefore, many manufacturers are using glue way to improve the power supply heat dissipation, and improve the insulation of power supply and heat dissipation, if the 7 shows.

 

Due to the control of LED, so the manufacturers have developed LED lamp dimming. The main tune of the existing light way SCR dimming and PWM dimming and 0-10V dimming and DALI dimming and DMX51 dimming, dimming power line carrier, is controlled by the LED drive current or voltage, brightness change LED.

 

3 Lamp Shell Radiator

Where is the main consideration of the lamp shell radiator manufacturers design ability. Most manufacturers are using aluminum radiator materials, processing technology, such as organic processing and mold forming. In the structure design, the manufacturers in order to increase the cooling capacity of the lamp, usually using fins, as shown in

8.jpg

In addition, the lamp is also useful for making part of thermal plastic or ceramic material, adopt mold forming way. These two kinds of materials have good insulation performance, so that the product has a high electrical safety performance, and is convenient for the safe isolation of internal LED drive. However, the thermal conductivity of these two materials is low, which is not conducive to heat conduction. In addition, plastic materials are light weight characteristics, can make the LED light weight has been reduced greatly.


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