日期：2012年6月11日

The beautiful led lights effect can not afford the high cost of injury

Advances in technology, skills enhancement, car manufacturing has brought more changes. In recent years, the popular group of the led lights  give us a shine. With widely used “daytime running lights”, both beautiful “angel eyes” began to appear in the streets. When people enjoy these cool equipment that brings the visual pleasure at the same time, the problem behind also call for deep thought. Recently, the “Southern Metropolis Daily” damage replacement the led lights produced by the high cost and inconvenience, were reported. How to properly treat these problems become our focus today.

Mr. Dai of the professionals of the automotive lighting systems address this issue, put forward our point of view: auto parts manufacturing, including lighting systems, and design concept, the formation of the trend of more and more accessories difficult to replace of the entire assembly. Therefore, the supply of the spare parts on the market will be involved towards the whole plant maintenance solutions.

Compared with the old car used the traditional light bulbs, LED lamps have long life, better advantages of the lighting and more beautiful appearance. Automotive headlamps when using,  give a heat issue, leading to the surrounding temperature high, and difficult for cooling heating. The width light LED car made the normal operating temperature is below 60 ℃, when the temperature exceeds 60 ℃, the LED becomes less stable. Therefore, the biggest factor to affect the efficiency and lifetime of LED automotive lighting is the temperature. Therefore, If the headlamp of the surrounding temperature exceeds a certain temperature, the LED is very easy to burn, even sometimes the base of the LED lights will directly melt. For most of vehicles using LED lights, if the diode damage is more serious  and need to directly replace the assembly. Therefore, it is recommended to use good LED thermal conductivity. Moreover, in the use of the led lights , If not all lights do not shine, the number of fault lights affect the results of case, the entire assembly to be replaced, thus to keep maintenance costs to a minimum.

How to reduce the replacement cost of the owners? and also improve the existing LED High Bay technology is the problem facing in various car manufacturers. As customer, they should have a correct understanding and application of new technologies, not to use some improper way to safeguard their rights.

Introductions of LED testing methods (3)

Thermal property of LED refers to thermal resistance and PN junction temperature. Thermal resistance is the ratio of temperature difference in channel to its power consumption. Resistance and junction temperature are two important parameters which will impact an influence on LED High Bay photoelectric properties. There are two main methods for measuring LED junction temperature: using infrared microscope and micro-thermocouple to measure the surface temperature of LED chips. This value is approximately equal to LED junction temperature. Another method is to calculate temperatures of PN junctions according to the current-temperature relations. The later is more accurate than the former and has been widely used.

Thermal property of LED refers to thermal resistance and PN junction temperature.

Reliabilities of LED Lights include electrostatic sensitivity characteristic, service life and environment properties. Electrostatic sensitivity characteristic is the maximum electrostatic voltage that LED can endure. Some LEDs have higher resistivity and longer distance between positive electrode and negative electrodes. When electrostatic charge accumulated to a certain amount on both ends, PN junction will be breakdown. In more serious conditions, LED will be destroyed directly. Thus electrostatic sensitivity test for LEDs is necessary before installing them onto lighting boards.

 

Service life of LED Projects is calculated though another parameter: light attenuation, need long-term tests. In order to obtain an average value, scientists need to choose LED samples randomly. Through long-term observation and statistics to estimate the average working life of LEDs.

 

Environment characteristics of the LED need to be tested in simulated conditions. Like high/low temperature impact test, humidity cycling test, salt spray test, dust test, irradiation test, etc.

 

All LED testing methods mentioned above have strict international standards. As for electrical property tests, final reports should contain curve graph for forward bias voltage, backward bias voltage, forward bias current and backward bias current in accordance with related standards. Tests for luminous flux should using 2π structures. Light intensity should be measured in conditions provided by CIE-127. Spectrum tests, thermal property tests, service life tests all have their own standards.

 

LED has been developed more than ten years in China, there still lacking of scientific and effective standards. Standards for LED testing methods can eliminate differences that exist in LED testing in different regions. In other words, it can help realizing the unification of the commodity. The testing results can truly reflect the overall level of Chinese LED industry.

 

scientist of the led lights

Who invented LED? Nick Holonyak, Jr. is the right person? LED (led lights) is the name of the theoretical formal light-emitting diodes, a solid light-emitting device, the solid semiconductor chip as luminescent material, the epoxy package by the carrier in the semiconductor compound release excess energy caused by photon emission , there is no filament light easy to burn, heat deposition, the light fades and other shortcomings, the direct issue of red, yellow, blue, green, blue, orange, purple, white light.

scientist of the led lights

LED lighting products are the use of LEDs as a light source created by the lighting apparatus. LED is called the fourth generation of lighting source of light or green light, with energy saving, environmental protection, long life, small size, can be widely applied in various directions, display, decorative, and backlighting, general lighting and urban night scene of the field. In recent years, some of the world’s economically developed countries around the development of LED (led lights) launched a fierce technology race, and for example the United States since 2000 to invest $ 500,000,000 to implement the National Semiconductor Lighting Project, the EU also announced the launch of a similar rainbow in July 2000 plan, all hope to be able to sweep away the old era incandescent bulb.

As LED is small size, fast response, long life, LED lamps, anti-shock resistance, can improve the utilization of the limited car space, especially in energy-saving issue, LEDs are becoming the choice for headlamp light

The hot issues of the LED to become a world focus, then who first invented the LED? In 1962,  Nick Holonyak, Jr., he was just a large U.S. firm General Electric Company of an ordinary researchers, to create the first a red LED, and he also believes that can emit light of other wavelengths in the future, there are many different colors of light means that the LED (led lights) and incandescent lights must be LED to replace out. Nick Holonyak, Jr. Bell Telephone Laboratories in the University of Illinois (Urbana Champaign) to obtain a Ph.D. in electrical engineering (EE), and in 1954 earned a doctorate and enter one of the most important private research institutions, he only 26 years old, filled with outstanding talent. 1954, when he entered the United States Army began to enter after the 1957 GE, continued until 1963, also invented the first a red semiconductor laser device, which is of LD, known as laser diodes, is a key component of many later CD-ROM device, a printer or copier device. Nick Holonyak, Jr. invented the LED, in 1963 from GE, as his alma mater, that is, we mentioned earlier, the University of Illinois professor of Electrical Engineering, specialized personnel training at home, as well as the morality of the scientist. Many of its students were later set up his own business in Silicon Valley, California, USA, participated in the Silicon Valley technology wave driven.Nick Holonyak, Jr. invented the brake fluid (Thyristor), also known as thyristors have to let AC, DC the ability to convert each other, with some help for the future of electrical energy storage, the world’s three power through the thyristor conversion.

 

high power led price continued to fall 20%, half of domestic fear factory will close down

Overcapacity, high power led price are falling down, probably make half of production used in Sam sung Electronics (Sam sung) LCD TV, Sharp, computer display back-light light-emitting diode (LED High Bay) industry closed down. The only survival industry is the one who gets countries to foster. HSBC (HSBC) Jerry Tsai analyst pointed out that, the global television, computer sales weakness in fear so that LED Street Light prices continued to fall 20% in 2012. For smaller domestic LED industry, factory closings will be the only option. In contrast, the market capitalization of $2.8 billion LED giant safety photoelectric (San-an Optoelectronic Co.Ltd.), Guang dong Elect (EEC-Tech International Co.Ltd,) and other large-scale industry will continue to receive  government subsidies and continue to operate. Noumea Securities analyst Anne Lee said that this is domestic policy, they want the largest industry to survive.

According to the report, the recent capacity utilization rate in most of domestic LED is amounted to only 50%, the industry in 2010 and 2009 bought about 700 LED Lights manufacturing equipment, there is as many as half is in idle state. However, although the high power led price and market growth rate keep slow, yet about 2000000000 yuan of cash of large LED industry still intends to expand production capacity. UBS ( UBS ) report, Tokunho Junta has previously purchased 50 metal organic chemical vapor deposition system ( MOCVD/LED crystal growing equipment ), expecting this year that will purchase 100 sets .An op-toelectronic also plans to buy more MOCVD devices.

The report in the beginning of May, in accordance with the domestic incandescent lamps road map” requirement, this year 2012, in October 1st, 100W or more general lighting incandescent will be officially eliminated. By March 20th, the Ministry of finance, organized the 2012 semiconductor lighting products financial subsidies to promote the project. And it will be held in Beijing and invite public bidding. About 110 domestic enterprises are participated in the bidding. According to the reflect of many LED enterprises, this round of bidding is set a number of restrictions. Such of the requirements of energy-saving certification.

In fact, some news are spread in the industry of last year. The subsidy policy will have a change in style after, to provide ten enterprises subsidies, and to accelerate industry preferred and eliminating the inferior, and to breed competitive brand LED.

heat sink design of top led lighting companies

LED applications is now becoming more diversified, due to the high-power LED input power of only 15 to 20% into light, and the remaining 80-85% is converted into heat, if heat is not timely discharged to the outside world, then will make the LED High Bay chip interface temperature is too high to affect the luminescence efficiency and luminescence lifetime from the top led lighting companies. As the LED materials and packaging technologies continue to develop, to promote the brightness of the LED products, continuously improve, more and more wide application of LED, the LED as a backlight of the display, it is the recent hot topic is mainly different types of LED backlight technology more in color, brightness, life, low power consumption, degree, and environmental aspirations than traditional cold cathode fluorescent (CCFL), and therefore, actively involved in attracting industry.
heat sink design of top led lighting companies
The first single-chip LED power is not high heat, heat a big problem, so the package is relatively simple. As the LED materials technology continue to make breakthroughs in recent years, LED packaging technology change, and gradually developed into a flat, large area multi-chip package module from the shells of the early single-chip type package; its operating current from the early 20mA about low-power LED Street Light, progress to 1/3 to about 1A, high power LED, single LED input power up to 1W, even up to 3W, 5W package evolution.

In lighting applications, such as the mini-projector, vehicle and lighting light source, the required amount of lumens in a particular area need more than thousands of lumens, or ten thousand of lumens, single-chip package module alone is clearly insufficient to meet toward multi-chip LED package, and chip adhesion substrate future trends of the top led lighting companies.

Heat problem is a major obstacle for LED development for lighting objects from top led lighting companies, using a ceramic or heat pipe is to prevent overheating, but the thermal management solutions to the rising costs of materials, high power LED thermal management designed to effectively reduce R junction-to-case thermal resistance between the chip cooling to the final product, one solution of the material, to provide low thermal resistance, high conductivity, to make the heat directly transmitted from the chip to chip attached or hot metal outside of the package shell.