月份：2012年7月

solar led flood lights outdoor and lighting source

With the herd phenomenon of the market, as consumers, use LED lights remains to be calm, scientific analysis, the choice of the best cost-effective light sources and lamps, here are several basic performance of the LED:

1, the brightness of the LED brightness, different prices. LED lamps for LED should be consistent with the Laser Level Class I standards.

2, the antistatic ability antistatic ability LED, long life, and hence the price is high. The antistatic usually greater than 700V, the LED can be used for LED lighting.

Wavelength wavelength LED, the same color, such as requiring the same color, the price is high. No the LED spectrophotocolorimeter instrument manufacturer it is difficult to produce pure colors products.

4, the leakage current LED is one-way conductive light, if the reverse current is called leakage, the leakage current LED street lights, life is short, low prices.

solar led flood lights outdoor and lighting source

5, the use of different light angle of the LED emitting angle. Special light-emitting point of view, higher prices. If all diffusion angle, the higher prices.

6, critical to the quality of life is life, life light bad decision. Light decay, long life, long life and high price.

7-chip LED light chip, different chips, the price difference. The chip is more expensive in Japan, the United States, generally made in Taiwan and chip prices lower than the Japanese, the United States.

8, the size of the chip size chip to the side, the quality of large-chip LED is better than small chips. Prices are proportional to the chip size.

The colloid ordinary LED colloidal general epoxy resin, plus a more expensive price of the LED UV and fire retardant, high-quality outdoor LED lighting should be UV and fire. Each product will have different designs, different designs for different purposes, the reliability of LED lighting design include: electrical safety, fire safety, the application of environmental safety, mechanical safety, health and safety, safe use of time and other factors. From the electrical safety point of view, should comply with the relevant international and national standards.

LED is a new product, the Chinese national standards lag, but the national product qualification testing. LED lighting prices with the international safety certification (such as GS, CE, UL and so on) and the national product quality certification must be high, because these products in the security design is reliable. The attention of consumers is to carefully identify the authenticity of the certificate, certificate of international safety certification and the national product manufacturers are not many.

From health, the price of non-toxic materials designed to be high, especially in indoor LED lighting, do not cheap selection of LED lighting, odor, currently only a few LED manufacturers is produced using non-toxic materials, identify the directly with the nose, respectively, the smell of products than the lower price without the smell. Like lead, mercury, cadmium and other toxins need professionals. Look for environmental safety, reliable dust-proof design, the high price of materials, fire protection, UV protection, anti-low temperature cracking of LED products.

solar led lamp post and power supply

LED power supply there are many classification methods:

Divided into constant voltage output characteristics of series, the constant current series;

Different input characteristics are divided into general series, and high power factor series;

For different purposes, divided into the waterproof series, series and is not waterproof;

Isolation circuit structure is divided into different series, and the isolation series;

Control mode is divided into different adjustable light series, and dimming series.

solar led lamp post and power supply

LED environmental protection, long life, high photoelectric conversion efficiency of the many advantages of theory, the service life of LEDs over 100,000 hours, but in the actual application process, due to the inappropriate choice of the design of drive power and drive mode, or with LED lights do not match the LED are easily damaged or light failure is very serious. reduces the reliability of the LED lamps.

LED manufacturers and LED specifications, current, voltage characteristics are different now to the typical specifications of the white LED, for example, in accordance with the LED current, voltage variation, the general application of the forward voltage of about 3.0-3.6V, typical voltage of 3.3V, current is 20mA, the ends of LED forward voltage exceeds 3.6V, the forward voltage of a small increase in the LED forward current are likely to become doubled up, the LED light emitting body temperature has ascended faster, thus speeding up the LED light attenuation, and shorten the life span of the LED, serious and even burn out the LED to the LED voltage, current changes in characteristics, strict requirements on the design of the drive power.

Many manufacturers of LED light products (such as guardrail, light cup, projection lamps), with resistance, the step-down, and then coupled with a Zener diode voltage regulator, power supply to the LED, so to drive the LED there is a big defects, the first is low efficiency, consume large amounts of electricity on the dropping resistor, and may even be more than the electricity consumed by the LED, and can not provide high current drive, because the current increases, the greater the electricity consumed in the dropping resistor. so many products of the LED can not parallel, are used in series to reduce the current stable voltage capability poor, can not be guaranteed by the LED current does not exceed their normal work requirements, the design of products will be adopted to reduce the LED voltage across supply-driven, this is to reduce the LED brightness at the expense of using resistance, step-down mode to drive LEDs, LED brightness can not be stable when the power supply voltage is low, the LED brightness dimmed, high voltage power supply The brightness of LED street lights. resistance, the biggest advantage of the step-down manner to drive the LED is low cost.

According to the LED current, the voltage changes the characteristics of constant voltage LED drive is feasible, although the commonly used voltage regulator circuit, there is the disadvantage of poor regulation accuracy is not enough and steady flow, but in the application of certain products may be too precise design its advantage is still the other drive mode can not be replaced.

Constant current drive, is an ideal LED driver, it can avoid the LED forward voltage changes caused by the current changes, constant current LED brightness and stability, so many manufacturers choose the constant current mode to drive LEDs.

However, due to a variety of different LED power performance and conversion efficiency vary, so choose a suitable, efficient LED special power supply, can be truly revealing the high performance characteristics of the LED light source because of the low efficiency of LED power you need to consume large amounts of electricity to the LED-powered, so highlights the characteristics of the LED energy-saving LED power LED work stability, energy efficiency, longevity, have an important role.

solar led lighting outdoor and led solution

Most lighting designers believe that the quality of all LED products are the same. However, many LED manufacturers and suppliers, Asian manufacturers to global supply low-cost LED. Surprisingly, only a small part of these manufacturers to create high-quality LED. For applications that only used as a simple indicating the role of the low quality of the LED is sufficient to meet the requirements. However, in many areas of the requirements of consistency, reliability, solid-state instructions or lighting must be high quality LED lights, especially in harsh environments, such as highways, military / aerospace, and industrial applications.

solar led lighting outdoor and led solution

Safety requirements is very harsh, LED must meet high quality requirements of the fundamental factors in the environment of the New York subway station.

What are the factors that distinguish between the LED level of quality? How to tell the difference between the two LED’s? In fact, the selection of high quality LED from the chip until assembly is complete, during which there are many factors to consider. Tier-OneLED manufacturing company to produce excellent and consistent indicators wafer start from the high-quality LED manufacturing materials, enough to make a good chip. Determine the conditions of the LED performance, the chemical materials used in wafer production process is a very important factor.

A 2-inch wafer can be cut out more than 6000 LED chip, there is only individual chip performance and overall. A good chip manufacturer makes chips in the difference of color, brightness, and the voltage drop is very small. When the LED chip package is completed, many of their performance, there may exist a great difference, such as perspective. In addition, the impact of packaging materials is quite large, for example, silicone epoxy performance.

Classification ability

Excellent LED manufacturers can not only produce high quality chips, but also has the ability, depending on the LED color, brightness, voltage drop and perspective of its classification packaging. High-quality LED suppliers to provide customers products with consistent operating characteristics, while lower-quality LED suppliers only provide LED similar to the “mixed”.

For high-end, quality-demanding applications, such as the boundaries of the airport runway lights must meet the FAA-class color and brightness specifications, to ensure consistency of performance and security, LED packaging is strictly limited. Packing poor LED is used in demanding applications will lead to premature failure and other non-consistency problem is likely to lead to major accidents. Avoid the use of “mixed” products in the high-end and quality demanding applications in order to avoid equipment downtime, and ensure that the provisions in the design of the LED with reliable operating characteristics, it is very important.

Products supporting capacity

In addition to the separation of the assembly and supply of LED, LED indicators for its performance, brightness and color have a very significant impact. Due to ambient temperature, operating current, the circuit structure, voltage spikes and environmental factors and so can affect the LED performance indicators, the appropriate circuit design and assembly is critical to protect the LED and to ensure performance. LED tube manufacturers use a variety of techniques and different materials to design the circuit structure and assembly, in most cases, the LED assembly on the experience level of the difference will cause the LED in the same application there are differences in overall performance and reliability.

With the rapid growth of the LED needs, serve the global market manufacturers and assembly plants also increasing rapidly. It is regrettable that the surge in support for manufacturers not only a large number of low-quality LED packaging and LED design engineers to experience a relative shortage of Therefore, in addition to the existing experience and accurate screening LED suppliers, OEM manufacturers must also examine their circuit design and assembly technology to ensure that it meets the design specifications, and design to provide sufficient cooling capacity, because the cause of LED failure and performance The inconsistency of the main factors is overheating.

To ensure that it meets design requirements, the OEM must detect the LED assembly and the circuit structure

Third-party testing

In order to eliminate the injustice that exist in the test, many companies have commissioned a third-party to test the LED assembly and circuit structure. LED devices may be tested in the harsh environment, or use a few weeks. During the test, at the same time the pressure, temperature cycling, fixed voltage / change current fixed / change test, test to determine whether the LED to meet the application requirements in other harsh environmental conditions. Test before and after a large number of parameter changes must be recorded at the same time to monitor the changes in the measured LED brightness, color, and voltage drop.

Accelerated life cycle testing is a key test to avoid failure in special applications. The test helps to ensure that screen out those expectations at least for 100,000 hours, but only work 1000 hours in advance of failure LED. This situation may arise because of the low-quality LED (high quality LED assembly designed to be unreasonable) will reduce the brightness after 1000 hours of work. In fact, if a lower-quality LEDs have a higher drive current at an early stage is high-quality LED is brighter, however, the excessive current causes the LED heat too fast, the final results are dimmed or burned.

 

In addition, the assembly technology to some extent on the LED performance than the chip itself is also a big example. The design engineer should ask for the reliability of the specifications of LED to LED suppliers, and the LED assembly and testing to ensure that the relatively high brightness is indeed better. Some excellent LED suppliers can guarantee the reliability of their LED assembly can be sustained for three years or longer, and can further provide the ultimate LED products, including the appropriate design with high quality LED and for special applications.

The importance of the detection

Two applications within the field of transport helps to explain adequately tested, how to prevent the LED fails to provide a high degree of visibility applications. In the early 1990s, LED brake lights for cars and trucks. Some LED designs quickly inconsistencies in the performance indicators, and soon burned down, the reason is perhaps due to the quality of the LED, perhaps completely the design of the product itself. Until recently, the traffic lights be more appropriate, when the LED light, this phenomenon was attention. The design covered with LED diameter of 8 inches or 12 inches of PCB companies must consider in the choice of the LED and to improve the design environment and application requirements.

Any of the above situation, if the stress tests or accelerated life cycle testing has been done can be considered high-quality LED or LED assembly is qualified, it can be applied to require a longer service life and higher reliability the occasion.

Rational use of

Not every application needs high-quality LED assembly technology. If the LED assembly does not meet the requirements of harsh environments, the application will not necessarily greater security risk, or, if the maintenance costs of the final product is not very high, the use of poor assembly techniques may be more appropriate.

The most fundamental point is that the LED must be able to afford. Therefore, the cost requirements within the constraints, we must consider the supplier of the product packaging grade, assembly design experience and testing. Designed to meet application and market demand is the most effective means to serve the end user. If the application requires high-end solution, then the chip vendor’s choice of design experience, and testing are all factors to be considered. If you do not consider the sales prices of high-end products, it should be carefully considered other relevant factors of the difference between good and bad LED. Have to classify the ability of packaging grade LED suppliers, as well as to reliability, accelerated life cycle testing, manufacturers can be long-term cooperation, which helps manufacturers to adopt more reliable LED development of high-end products.

solar led street lamp and quality

How to control and improve the quality of full color LED display? What is the important indicator reflecting the quality of the full color LED display LED? The first LED devices as the most critical components of the full-color LED display for three reasons:

solar led street lamp and quality

First, LED full color machine used in the largest number of devices per square meter will be used only a few thousand to tens of thousands of led lights;

Secondly, LED is to determine the main body of the optical display performance of the entire screen, a direct impact on the evaluation of the audience on the screen;

Again, LED display the overall cost of the proportion of the largest, ranging from 30% to 70%. LED choice determines the quality of more than 50% of the entire display. If not other parts of the good LED, display, even the best can not make up the display quality defects.

Reflect the quality of the full color LED display LED indicators are:

First, the failure rate

The full-color display by the tens of thousands or even hundreds of thousands of clusters of red, green, composed of blue LED pixel composition of any one color of LED failure will affect the display of the overall visual effect. In general, industry experience in the LED display assembly to the aging failure rate in the 72 hours before shipping should be no higher than three ten thousandths (LED device itself causes the failure).

Second, the antistatic ability

LEDs are semiconductor devices sensitive to static electricity can easily cause static failure, antistatic ability is critical to the life of the display. In general, LED’s body static mode test failure voltage should not be less than 2000V.

Third, the attenuation characteristics

Red, green, blue LED bulbs With the increase in working hours, the light attenuation characteristics. The pros and cons of the LED chip, The quality of the auxiliary materials and packaging technology standards determines the level of the decay rate of the LED. In general, the light test of 1000 hours, 20 mA at room temperature, the attenuation of the red LED should be less than 10%, blue, green LED attenuation should be less than 15%. Consistent attenuation of red, green, blue, full-color LED display white balance impact, thereby affecting the display fidelity.

Fourth, the brightness

LED brightness is an important determinant of the brightness of the display. LED brightness higher the margin the greater the current, on the saving power, to keep the LED stability is good. The LED has a different value of the angle, the case of chip brightness has been set, the smaller the angle, LED is more bright, but the smaller the viewing angle. 100 degree LED general should be chosen in order to ensure a sufficient display of perspective. Different spacing and different line of sight of the display brightness, angle, and the price to find a balance.

Five, consistency

Full-color display is composed of numerous red, green, blue LED pixel blocks, the brightness of the LED panel of each color, the consistency of the wavelength determines the brightness of the display consistency, white balance, consistency, chroma consistency. In general, the display manufacturers require device suppliers to 5nm in the wavelength range and 1:1.3 brightness range of LEDs, these indicators reach by the device supplier through the color separation machine grading. Voltage consistency is generally not required.

 

solar led street lamps and good points

LED display screen, LED electronic display screen appears more and more people’s vision, LED lighting is some of the main road on the trial of the LED lights, LED street with what conditions?

solar led street lamps and good points

(1) energy saving voltage, low current, high brightness features. LED lights use LED street must have the characteristics of low voltage, low current, high brightness, ensure that the installation, normal use, energy efficient.

(2) new green light, LED use a cold light source, glare-free radiation not to issue a hazardous substances. The environmental benefits of better LED, ultraviolet and infrared spectra, and recyclable waste, mercury element pollution is safe to touch, is a typical green lighting.

(3) long life. LED street due to the continued use of replacement require a volume to replace them is too much trouble, when selected, long life are also important factors, Sheng Hao of the light produced by LED lighting, the basic use of age in 50,000 hours more fully comply with this condition.

(4) The lighting structure is reasonable. LED lamps will completely change the structure of the lamp, according to different requirements, the structure of the LED lamps to improve the brightness of the initial conditions, after the rare earth again increase the brightness, and the improvement of the optical lens, the brightness. The solid-state light source LED is encapsulated with epoxy resin, glass bulb filament and other easily damaged parts in its structure, an all-solid structure, is therefore able to withstand vibration and shock, without being damaged.

(5) light colors and simple, light and color. Must be used as street lights LED street light color simple, without too much noise at the same time to ensure that the lighting levels need to ensure road safety.

(6) safe. The use of low voltage LED light source, light stable, non-polluting, no 50Hz flicker when the AC power supply, no UV-B band, the color rendering index Ra is close to 100 color temperature of 5000K, closest to the sun the color temperature 5500K. Low heat thermal radiation, cold light source and precise control of the light pattern and light-emitting angle of light color and soft, no glare; without mercury sodium and other elements that might jeopardize the substance of the LED lights.

solar led street light circuit and led high power

High-brightness light-emitting diode (LED lights) for its small power consumption, long life, fast response speed, no flash, small, non-polluting, easy and integrated features, is becoming the traditional lighting industry upgrading to a new generation of light. In energy saving, environmental protection have become an increasing concern today, semiconductor lighting is to become the new economic growth point, and thus attaches great importance to by governments around the world, the scientific community and industry. So far, the United States, Japan, Europe, mainland China and China Taiwan, etc. have been launched their own semiconductor lighting, high power LED lighting industry has become one of the most watched industry.

solar led street light circuit and led high power

It is worth noting that so far upstream epitaxial silicon technology has been mature and stereotypes, cheap LED chips have been able to meet the needs of the lighting, the transfer and development of pricing forward midstream terminal market of packaging and downstream applications. This means that who-chip applications, to create a long-life, high-efficacy power LED lighting products, who is likely to become the ultimate winner of the LED industry. High power LED lighting package and the application of the problems have become prominent, one of the most critical is how to solve the heat problem of high power LED lighting, this is not only the technical aspects of structural design and engineering applications, but also involves the thermal management mode and fluid mechanics, and other scientific issues. Completely different with the three-tier structure of the existing chip aluminum plate and a heat high-power LED series lighting technology, we developed an integrated chip integration of a cooling (two-story structure) high power LED lighting series lamps “in the technology roadmap may have the significance of the revolutionary and subversive, will become a new direction of development of high power LED lighting industry.

A high power LED lighting product status

LED luminous efficiency can make about 30% of the energy converted into light, the remaining 70% of the energy is almost converted into heat, so that the temperature of the LED. Its heat is very small, low-power LEDs, basically do not have to take cooling measures can be applied, such as instrumentation lights, lights, small-size LCD screen backlight and so on. When applied to the field of commercial buildings, roads, tunnels, mining and other lighting for high-power LEDs, the heat is a big problem. If the heat of the LED chip can not spread it out, will accelerate the aging of the chip, the light fades, color offset, shortening the life of the LED. Therefore, the structure model and thermal management design of high power LED lighting system is very important.

All high-power LED lighting on the market today are made of chip aluminum plate heat sink three-tier architecture model “, that is the first chip package formed aluminum panel LED light source module, and then the light source module placed on the radiator manufacturing into high-power LED lighting.

It should be noted that the high-power LED thermal management system still used in the LED early for lights and display lights, small power LED thermal management mode. Chip aluminum plate heat sink three-tier architecture model “Preparation of high-power LED lighting, there are obviously unreasonable in terms of system structure, such as the structure between contact resistance and high junction temperature, low thermal efficiency, so the chip The heat released can not be effectively export and shed be in the path, leading the LED lighting light efficiency is low, the light fades, life is short and can not meet the lighting needs.
How to improve the package thermal capacity is one of the key technologies of this stage, high-power LED to be solved. The direction and focus of the development of LED lighting products are: high power, low thermal resistance, higher light, low light, small size, light weight, thus making the cooling efficiency of the LED’s have become increasingly demanding.

However, due to the restrictions of the structure, cost and power consumption and many other factors, high power LED lighting is difficult to use active cooling mechanism, but only the use of passive cooling mechanism, but the passive cooling has greater limitations; and LED energy conversion efficiency than low, is still about 70% is converted to heat, even if the luminous efficiency to 1 times 40% of the energy into heat. In other words, it is difficult to do not consider the extent of heat dissipation, so in the long run, the cooling of high power LED lighting is a long-standing problem.

The timing of high-power LED for lighting is now mature, and the development of efficient natural cooling thermal management systems, has become a high-power LED lighting to achieve the prerequisite and key factors of industrialization. Therefore, new technologies routes and system architecture to completely solve the cooling problem of high power LED lighting.

Two new, high-power LED lighting industry technology roadmap

Existing high-power LED lighting cooling technology exists to thermal resistance, low heat capacity, we are trying to chip a heat integration (two-story structure) model “to address the low luminous efficiency of high power LED lighting, the light fades serious cost Advanced series of questions.

2.1 technology roadmap

Chip a heat integration (two-story structure) mode, not only to go in addition to the structure of the aluminum plate, but also multiple chips on directly placed on a heat sink to form a multi-chip module single light source, was prepared by the Integrated High Power LED lamp, light source for the single, showing the surface light source or cluster light.

2.2 The key technology

How to enhance the ability to conduct heat to the chip, reduce the thermal resistance of the interface layer, related to the structural model of thermal management systems, fluid mechanics and super-thermal conductivity materials engineering applications; how to effectively control the heat storage of the heat dissipating base, planning convection heat path, the establishment of efficient natural convection cooling system, proceed from the lamp structure design.

2.3 The technical program

By changing the package structure of LED light source, the structure of cooling and lighting structure model to reduce the thermal resistance layer; super-thermal conductivity materials, to increase the thermal conductivity of the chip heat source; to optimize the thermal management system based on “chip a heat integrated two-story structure, increase air flow, the formation of natural convection.

2.4 The design concept

Prepared to take a modular high-power LED lamps. Package of light, heat, shape and structure as a whole module between the module is independent of any one module can be replaced individually when a partial failure, simply replace the faulty module without having to replacement of other modules or the overall change will be able to continue working normally. All modules part of the lamp can hand disassembly, convenient, fast, low-cost maintenance.

2.5 Design Points

System module, in addition to meet the heat lamp replacement requirements must be met for the optical (optical efficiency) demand for LED lighting, and modeling (market) demand.

3, a cooling chip integrated structure Introduction

“Chip a heat integration (two-story structure) mode is a new type of LED light source package model, structure model and thermal management system mode. High power LED lighting, the use of the technology model prepared not only completely solve the heat problem, but also effectively solved such as the problems in the distribution of light, luminous efficiency, lifetime and maintenance, has developed a long life, high luminous efficiency high-power LED series products, such as street lights, downlights, tunnel lamps, mining lamps, car headlights, landscape lights and other lighting equipment.

3.1 Technical Features

3.1.1 will be the chip and the aluminum alloy + thermal conductivity composite material matrix (radiator) to connect as a whole, the unique application of high-power LED packaging technology, will focus on multiple chip package directly on the heat dissipating base, so that the chip and the heat dissipating base the thermal resistance between the smaller, the entire cooling matrix is ​​a complete lighting, the formation of an integrated high-power LED lighting components.

3.1.2 design thermal management system based on the principle of bionics, the establishment of the two-story structure of chip integration of a cooling thermal resistance model to the junction temperature calculation and life prediction.

Chip, a heat integrated two-story structure is characterized by a direct heat source chip package on the radiator, as the heat source temperature increases, air flow occurred in the porous heat sink, porous flow channel for air convection, heat comes out automatically, to ensure the normal working of the chip in the safe use temperature range. Advanced thermal conductivity and thermal convection system to ensure good cooling effect, to further improve the luminous efficiency of the chip.

3.1.3 the chip (45mil × 45mi1), integrated package (chip concentrated in a small area), high luminous efficiency of the surface light source with high flux density, the total luminous flux, low-glare characteristics.

At present, the use of the technology has been fabricated chip heat integration (two-story structure) mode high-power LED lighting, such as street lamps, tunnel lights, downlights, spotlights. In addition, high-power LED car headlights are need to strengthen the cooling fans, difficult to meet the application requirements of the market-oriented, two-story structure made of cluster high-power LED car headlights, to solve the automotive light industry using LED light source the limitations of the manufacturing automobile headlamps

3.2 Product technical specifications and advantages

(1) cooling efficiency: the use of natural cooling methods, completely solve the problem of high power LED cooling (temperature <4 ° C, the heat sink temperature <60 ° C, measured under the conditions of the ambient temperature> 35 ℃);

(2) high current: rated current of the supply of chips in each tablet 400 – 450mA;

(3) High luminous efficiency: the entire lighting efficiency of 90.9 lm / W;

(4) long life:> 50 000h;

(5) The light is small: the lighting of Quality Supervision, Inspection and Testing Center: 1 000h life test matt decline;

(6) integrated: the integrated of COR (Chip On Radiator), the chip integrates directly bonding the radiator integrated with integrated bonding in the aluminum panel COB (Chip On Board) is completely different. Single, integrated chip showed a surface light source, a single light source or cluster light (installed glass lenses) injection;

(7) lighting effects with the conventional non-LED light source does not change the habits of mankind’s run out;

(8) structure is simple: easy to maintain, without the overall change.

4, high power LED lighting industrial technology development direction

At present, the technology roadmap for high-power LED lighting industry, we believe that there are two routes to choose from: one way is to continue along the chip aluminum plate and a radiator (three-tier structure) mode “technology roadmap development; other way is to open up the “chip a heat integration (two-story structure) mode” technology roadmap. Chip integration of a heat dissipation structure “is an emerging technology, in this structure, in addition to the chip, are new, including a cooling chip integration, packaging, power, complete sets of equipment, testing, and even standard , which makes high-power LED lighting products in the life and luminous efficiency, quality, design, controllability, cost and other aspects relative chip aluminum plate and a radiator three-tier architecture model “has a distinct advantage in high-power efficient semiconductor solid-state lighting research, application and industrialization of a new field that has much to offer.

solar led street lighting system and Phosphor

There are three main way to achieve white LED lights,  but they do not fully mature, thus seriously affecting the white LED lighting in the area. Specifically, the first method is the yellow phosphor coating a blue LED chip to be Blu-ray excitation, chips issued by the yellow light emitted by blue phosphor complementary form white light. The technology monopoly of Japan’s Nichia Corporation, and a schematic of the shortcomings of this program is that the emission spectra of Ce3 + ions in the phosphor does not have a continuous spectrum characteristic color less difficult to meet the low color temperature lighting requirements, while light efficiency is not high enough, the need to improve through the development of new highly efficient phosphor.

solar led street lighting system and Phosphor

The second method is the blue LED chip coated green and red phosphors, issued through the chip emits blue light phosphor green and red composite to get the white color. However, this method used in the phosphor conversion efficiency lower the efficiency of red phosphors need a more substantial increase.

The third method is the three primary colors or multiple color phosphor coating in the violet or ultraviolet LED flood lights chip, the chip launch of the long-wave ultraviolet light (370nm-380nm) or violet (380nm-410nm) to excite the firefly light powder to achieve white light emission.

For LED phosphors

Way to achieve white LED, the most widely used most mature a smear a layer of yellow phosphor on blue chips, blue and yellow mixed into white light, so the material of the phosphor for white LED The attenuation of a great impact.

Market the most mainstream of the phosphor is a YAG (yttrium aluminum garnet) phosphor, silicate phosphor, nitride phosphor with blue LED

Chip compared to the accelerated aging of white LED phosphors, and different manufacturers phosphor light decay is not the same degree of influence, which is closely related to the raw material composition of the phosphor. The Intematix white phosphor, so make a white LED compared to counterparts in the attenuation control has been greatly improved.

The LED phosphors with plastic steps

LED phosphors with plastic program is a part of the LED tubes production process is very important!

Preparatory work:

An open and inspect all of the LED production and use of equipment

With acetone to clean the small beaker with plastic.

Preparing the necessary production specifications book or contact list, and the corresponding model glue, etc and confirm its effective use during the period.

Start with the glue:

1, with a rubber order: Yue He agent + A glue mixed in proportion to the results and then join the proportion of mixed objects of the fluorescent powder + B glue. Then vacuum.

2, according to the ratio of the phosphor and production quantities of the production specifications or engineering notice to calculate the weight of various materials required.

3, adjusting the precision electronic four base electronic horizontal state.

4, a clean small beaker placed on a precision electronic scales to estimate E, according to production specifications book, the ratio of the phosphor, respectively, said fluorescent powder to take the weight required and A, B glue.

5, with a good manual mixing of the fluorescent powder ranging from 20-30 minutes, until the phosphor powder is evenly distributed.

6, with good fluorescent plastic vacuum to the invisible bubble of the state, after taking out on the room temperature with a clean glass cover use, prior to use basis having the same direction, slowly stir for 2 minutes to 3 minutes, stirring speed r 2-3 seconds.

solar panel led lights and Ceramic substrates

Ceramic substrate material for its excellent thermal conductivity and air tightness, widely used in the field of power electronics, electronic led lights packaging, hybrid microelectronics and multi-chip module. This paper briefly introduces the current status quo of the ceramic substrate and future development.

solar panel led lights and Ceramic substrates

1, Comparison of plastic and ceramic materials

Plastic, especially the dominance of the epoxy resin due to the relatively good economy, so far, still occupy the entire electronics market, but a number of specific areas such as high temperature, does not match the linear expansion coefficient, air tightness, stability, mechanical properties, such as clearly not suitable, even in epoxy resin, add plenty of organic bromide to no avail.

As opposed to plastic materials, ceramic materials are also of the electronics industry plays an important role in its resistance is high, prominent high-frequency characteristics, and has a high thermal conductivity, good chemical stability, thermal stability and melting point advantages. In electronic circuit design and manufacturing of these performance ceramics are widely used in different thick film, thin film and the circuit substrate material can also be used as an insulator, heat conduction path and with the demanding circuit in the thermal performance requirements to create a variety of electronic components.

2, various ceramic materials

2.1 Al2O3

So far, the alumina substrate is the most commonly used substrate material in the electronics industry, because the mechanical, thermal, electrical properties relative to most other oxides ceramics, high strength and chemical stability, and a rich source of raw materials, applicable to all kinds of technology to produce different shapes.

2.2 BeO

With even higher thermal conductivity than aluminum metal, used in situations requiring high thermal conductivity, but quickly lower the temperature exceeds 300 ° C,
The most important thing is that because of its toxicity limits its own development.

2.3 AlN

AlN has two very important performance worth noting: a high thermal conductivity, a coefficient of expansion matching with the Si phase. The drawback is that even in the surface of very thin oxide layer will have an impact only on the materials and processes, strict control in order to create a good agreement with the AlN substrate thermal conductivity. Large-scale AlN production technology of domestic or immature phase of Al2O3, AlN prices relatively high, this is restricting the bottleneck in the development. For these reasons, you can know that, due to superior performance, the alumina ceramic, to a dominant position in the field of microelectronics, power electronics, hybrid microelectronics, power modules, etc. or to extensive use.

3, the ceramic substrate led street lights manufacturing

The manufacture of high-purity ceramic substrate is very difficult, and most of the ceramic melting point and hardness are high, which limits the possibility of ceramic machining, ceramic substrates are often doped with low melting point glass is used to help melt or stick connected so that the final product is easy to machining. Al2O3, BeO, AlN substrate preparation process is very similar to the matrix material is ground into powder in about a few microns in diameter, with different glass flux and adhesives (including powders, MgO, CaO) mixed, in addition to the mixture organic binder and plasticizer and then milled to prevent the reunion homogeneous molding raw tiles, and finally sintered at high temperature. Ceramic forming the following methods:

Roller rolling slurry spray to a flat surface, partially dried to form a viscosity like putty-like sheet, and then the flakes into a pair of parallel rollers rolling grind to get a uniform thickness of the raw tiles.
● cast slurry through a sharp blade coating in a move to bring the formation of thin slices. Compared with the other process is a low-pressure process.
● powder sintering under the suppression of the powder in a hard mold cavity and to exert a lot of pressure (about 138MPa), despite the uneven pressure may produce excessive warpage, but this process is the production of sintered parts is very dense, smaller tolerances.
● such as hydrostatic powder to suppress the pressure of this process using the mold and use around the water or glycerol up to 69MPa pressure is more uniform made of parts warping.
● squeeze the pulp through the mold out of this process uses a slurry viscosity is low and difficult to obtain a smaller tolerance, but this process is very economical and can be thinner parts than other methods.

4, substrate type and its characteristics

More common at this stage ceramic cooling substrate type Total HTCC, LTCC DBC DPC four, HTCC belong to the earlier development of the technology, but because of the high sintering temperature so that the electrode material of choice is limited, and the production cost is relatively expensive. These factors have contributed to the development of LTCC is, LTCC co-firing temperature dropped to about 850 ° C, but the drawback is that the precise size, product strength is not easy to control. DBC with the DPC compared to the country in recent years was the development of mature, professional and technical, of the energy production of the DBC is heated to high temperatures combined with Al2O3 and Cu board, the bottleneck is not easy to solve the micro-pores between the Al2O3 and Cu plate This makes the mass production of energy and yield of the product subject to greater challenges, DPC technology is direct copper to the Cu deposition on Al2O3 substrate on top of the process of combining materials and thin film technology and its products In recent years, the most commonly used heat ceramic substrate. However, material control and technology integration capabilities are higher, which makes entering the DPC industry and stable production threshold is relatively high.

The development trend of high-brightness LED lightings

With the improvement of the LED lights performance, the applications of market grow rapidly and extensively. The future development of high-brightness LED grow lights market will be more rapid and extensive growth. Among it, the most obvious penetration rate is white LED lightings. In the late of 90th century, the context of environmental protection and energy saving by market expectations, and also stimulate the industry to quickly research and development the relevant technology. For now, the white LED applications, including mobile phone LCD back-lighting and automotive interior lighting, just these markets already account for about 25 percent of the overall LED sales.

The development trend of high-brightness LED lightings

On the other hand about the part of the lighting applications in the realm. General lighting of the building often accounts for 20% of the entire electricity consumption in Japan, the 1990s has been more than an annual $ 100 billion kWh. So the expectations for a new generation of energy-saving light source is quite large, but unfortunately so far, the white LED can only use a very small range. Like a small white LED lightings 5mm, it is not like a light bulb or fluorescent, only one will be able to use of the environment required for the amount of light. Therefore, if the LED can step into the architectural lighting, you need a bigger breakthrough in the overall technology job.

The basic structure of the high-brightness white LED

The white LED is basically in two ways. A multi-chip type, a single-chip type. The former is a three RGB LED package together at the same time making it luminous and produce white light, which is blue or violet. UV LED as the light source used in conjunction with the phosphor to produce white light. The former way, you must combine a variety of characteristics of LED driver circuit is more complex, only complex, only one kinds of the type of the latter single-chip LED, circuit design is relatively easy. Single-chip type is further divided into two categories, a Blu-ray LED lightings source, the other is to use the new-ultraviolet and ultraviolet light. Now, most of the white LED tubes market is the blue LED with YAG phosphor.

solar panel street lights and led drivers

LED power supply is also a supporting products currently on the market power quality is poor, the following businesses entering the bank to provide some knowledge of the LED drive power.

The characteristics of the LED drive power

(1) high reliability

Especially as the drive power of the LED lights installed in the high altitude, inconvenient repairs and maintenance spend.

(2) high efficiency

LED energy-saving products, the higher the efficiency of the drive power. Results cooling power installed in the fixture is very important. High efficiency power supply, the loss power, heat in the fixture, and reduces the temperature rise of the lamps. Beneficial to delay the LED light failure.

(3) high power factor

The power factor is the grid load requirements. Appliances generally less than 70 watts, there is no mandatory targets. Power is not a single electrical power factor on the grid has little effect, but the use of large amount of lighting at night, focus too much on similar load, the grid will produce a more serious pollution. 30 watts to 40 watts of LED drive power, said that in the near future, will power factors may have certain specifications.

solar panel street lights and led drivers

(4) drive way

Now common, there are two: one is a constant voltage source for the constant current source, each constant current source separately to each LED power supply. In this way, the combination of flexible, all the way to the LED fault, does not affect the other LED’s work, but the cost will be slightly higher. The other is a direct constant current power supply is in the Division Hui Bao “to drive the LED in series or parallel operation. Its advantage is low cost, but the flexibility is poor, but also to solve a LED fault, does not affect other LED running. These two forms co-exist within a certain period of time. Multi-channel constant-current output power supply, in terms of cost and performance. May be a future direction of the mainstream.

(5) Surge Protection

LED anti-surge capacity is relatively poor, especially the anti-reverse voltage capability. Is also important to strengthen this protection. Some LED lights installed in the outdoors, such as LED street lights. Kai rejection grid load and the induction of lightning from the grid system will invade a variety of surge, some surge can cause damage to the LED. Therefore, the analysis in Section Hui Bao “drive power in the surge protection should have a certain lack of frequent replacement as for power and lighting, LED drive power have to inhibit the intrusion of surge, the ability to protect the LED is not damaged.

(6) protection

Power in addition to conventional protection functions, the best increase in the constant current output LED temperature negative feedback to prevent the LED temperature is too high; to comply with the requirements of the safety and electromagnetic compatibility.

3, according to the drive mode.

(1) constant flow

Constant current drive circuit output current is constant, and the output DC voltage with the change of load resistance of different sizes within a certain range, load resistance is small, the output voltage, the greater the load resistance, the output voltage higher;

Not afraid of the constant current circuit load short circuit, but is prohibited to load completely open;

Constant current drive circuit driving the LED is an ideal, but the relatively higher prices;

Should be noted that the Maximum current and voltage values, which limits the number of the LED.

(2) The regulator type

When the parameters identified in the regulator circuit, the output voltage is fixed, the output current changes with changes in load;

The regulator circuit are not afraid of open-circuit load, but it is prohibited to load completely short-circuit;

Regulator drive circuit drives LED strings with a suitable resistor before each string of LED display brightness average;

The brightness will be affected by the rectifier from the voltage change.

4, the overall constant current and constant current work by road advantages and disadvantages

-By-channel constant current shortcomings more, the cost is relatively high compared with the overall constant current. But it can truly protect LED and extend the life of the LED-by-channel constant current is the future trend.

5, LED power less than

LED driver power supply shortage of reasons:

Production of LED lighting and related products, the company’s technical staff is not enough understanding of the switching power supply to make the power supply is working properly, but some of the critical assessment and electromagnetic compatibility consideration is not enough, or there must have hidden;

Most of the LED power producers are come to do transition from ordinary switching power supply LED power supply, not enough understanding of the characteristics of LED and use;

LED standard little, mostly refer to the standard switching power supplies and electronic ballasts;

Now most of the LED power supply is not unified, so the amount of most of the are relatively small. Small purchases, the price is high, and component suppliers uncooperative;

LED power supply stability: wide input voltage, high and low temperatures, overtemperature, overvoltage, etc. have no problem to solve;

First, the drive circuit as a whole life, especially the key devices such as: the life of capacitance at high temperatures directly affect the power of life;

LED driver should challenge the higher conversion efficiency, especially in the drive of high power LED high bay lights, because all is not as light output power as heat dissipation, the power conversion efficiency is too low, the impact of the LED energy-saving effect play;

Less power (1-5W) applications, the proportion of the cost of constant current drive power is close to 1/3 the cost of the light source has been close to a certain extent, affected the marketing.