Making white LED lamps requires you to have some basic knowledge. The LED needs to add a current limiting resistor or it will burn out.
LED is the abbreviation of light emitting diode in English. Its basic structure is a piece of electroluminescent semiconductor material, placed on a shelf with leads, and then sealed with epoxy resin around to protect the internal core wires, so the LED has good earthquake resistance
[Edit this paragraph] 1. The structure and light-emitting principle of LED
50 years ago, people already understood the basic knowledge that semiconductor materials can produce light. The structural diagram of light-emitting diodes. The first commercial diode was produced in 1960. Year. The core part of the light-emitting diode is a wafer composed of p-type semiconductor and n-type semiconductor. There is a transition layer between the p-type semiconductor and n-type semiconductor, called a p-n junction. In the PN junction of some semiconductor materials, when the injected minority carriers recombine with the majority carriers, excess energy is released in the form of light, thereby directly converting electrical energy into light energy. When a reverse voltage is applied to the PN junction, it is difficult for minority carriers to be injected, so it does not emit light. This type of diode made using the principle of injection electroluminescence is called a light-emitting diode, commonly known as LED. When it is in the forward working state (that is, forward voltage is applied to both ends), when the current flows from the LED anode to the cathode, the semiconductor crystal emits light of different colors from ultraviolet to infrared. The intensity of the light is related to the current. .
[Edit this paragraph] 2. Characteristics of LED light source
1. Voltage: LED uses a low-voltage power supply, and the supply voltage is between 6-24V, which varies according to different products, so It is a safer power supply than using high-voltage power supply, and is especially suitable for public places. 2. Efficiency: Energy consumption is 80% less than incandescent lamps with the same light efficiency. 3. Applicability: Very small. Each unit LED chip is 3-5mm square, so it can be prepared into devices of various shapes, and is suitable for variable Environment 4. Stability: 100,000 hours, light decay is the initial 50 5. Response time: The response time of incandescent lamps is milliseconds, and the response time of LED lamps is nanoseconds 6. Environmental pollution: no harmful metals Mercury 7. Color: Changing the current can change color. Light-emitting diodes can easily adjust the energy band structure and band gap of the material through chemical modification methods to achieve red, yellow, green, blue and orange multi-color LED lights. For example, an LED that is red when the current is small can turn into orange, yellow, and finally green as the current increases. 8. Price: LEDs are relatively expensive. Compared with incandescent lamps, the price of a few incandescent lamps is enough. The price is equivalent to that of an LED light, and usually each set of signal lights needs to be composed of 300 to 500 diodes.
[Edit this paragraph] 3. Types of monochromatic light LEDs and their development history
The earliest LED light source made by applying the semiconductor P-N junction luminescence principle came out in the early 1960s. . The material used at that time was GaAsP, which emits red light (λ p =650nm). When the driving current is 20 mA, the luminous flux is only a few thousandths of lumens, and the corresponding luminous efficiency is about 0.1 lumens/watt. In the mid-1970s, the elements In and N were introduced, allowing LEDs to produce green light (λ p =555nm), yellow light (λ p =590nm) and orange light (λ p =610nm), and the light efficiency was also increased to 1 lumen/watt. By the early 1980s, GaAlAs LED light sources appeared, making the light efficiency of red LEDs reach 10 lumens/watt.
In the early 1990s, the successful development of two new materials, GaAlInP, which emits red and yellow light, and GaInN, which emits green and blue light, greatly improved the light efficiency of LEDs. In 2000, the luminous efficiency of LEDs made by the former reached 100 lumens/watt in the red and orange areas (λ p =615nm), while the luminous efficiency of LEDs made by the latter in the green area (λ p =530nm) could reach 50 Lumens/Watt.
[Edit this paragraph] 4. Application of monochromatic LED It has been widely used in display screens and has produced good economic and social benefits. Take a 12-inch red traffic light as an example. In the United States, a long-life, low-efficiency 140-watt incandescent lamp is used as the light source. The LED linear light produces 2,000 lumens of white light. After passing through the red filter, the light is lost by 90, leaving only 200 lumens of red light. In the newly designed lamp, Lumileds uses 18 red LED light sources, which consume a total of 14 watts of power including circuit losses to produce the same light effect. Automotive signal lights are also an important area for LED light source applications. In 1987, my country began to install high-mounted brake lights on cars. Due to the fast response speed of LEDs (nanosecond level), drivers of following vehicles can know the driving conditions early and reduce the occurrence of rear-end collisions. In addition, LED lights have been used in outdoor red, green, and blue full-color displays, keychain miniature flashlights, and other fields.
[Edit this paragraph] 5. Development of white light LEDs
For general lighting, people need white light sources. In 1998, white light-emitting LEDs were successfully developed. This kind of LED is made by packaging GaN chips and yttrium aluminum garnet (YAG). The GaN chip emits blue light (λ p =465nm, Wd=30nm), and the YAG phosphor containing Ce3 made by high-temperature sintering is excited by the blue light and emits yellow light with a peak value of 550nm. The blue LED substrate is installed in a bowl-shaped reflective cavity and covered with a thin layer of resin mixed with YAG, about 200-500nm. Part of the blue light emitted by the LED substrate is absorbed by the phosphor, and the other part of the blue light is mixed with the yellow light emitted by the phosphor to obtain white light. Now, for InGaN/YAG white LEDs, by changing the chemical composition of the YAG phosphor and adjusting the thickness of the phosphor layer, white light of various colors with a color temperature of 3500-10000K can be obtained. In fact, LED lights are what we usually call energy-saving lamps. (This is wrong. The working principles of daily energy-saving lamps and LEDs are fundamentally different! But there is no problem with LED lamps being called energy-saving lamps.) LED lamps with different powers have different prices. Moreover, different processes and appearance materials will also cause price differences
[Edit this paragraph] 6. Comparison and competition of the advantages and disadvantages of new neon lights and LED lights
The following is for neon lights Compared with LED lights, the latest LED technology is included in the comparison. It is not the information you have seen on the Internet before. 1. Does the LED light source have a lifespan of 100,000 hours? According to the light decay of 7, it actually only has about 50,000 hours. According to the light decay of 3, the actual use can reach 80,000 hours. 2. Doesn’t the LED generate heat? Yes, it needs to dissipate heat. 3. Can LED replace incandescent lamps? Luminous flux, light efficiency and color rendering are OK, but they are currently too expensive and will not decline in recent years. However, the cost of replacing incandescent lamps can be reduced by increasing the luminous flux of the product. 4. Can LED be simply used as an ordinary light source? [2] No, it requires a driving power supply, optics and heat conduction.
5. Comparison of the performance and advantages of the two light sources. The advantages of neon lights have been covered by LED, but the current price of LED lights is too high. 6. Comparison of the power supply of the two light sources. LED has better low voltage, but has poor waterproofing and excessive current carrying capacity. The input current of a large 1-watt LED single lamp is 350mA. 7. The control technology of the two light sources is relatively easy to implement. LED is easy to implement, but neon lights are mature. 8. Comparison of the stability of the two light sources. LED has great inconsistency, while neon lights are quite stable. A few manufacturers can achieve relative stability, such as using CREE and AOD chips to combine the advantages of each chip. 9. Price comparison of the two light sources. LED is more expensive, but yellow and red are comparable. The most expensive one is LED white light. 10. Comparison of the two light sources for outdoor use. The poor waterproofness of LED is the fatal weakness of outdoor use. 11. Comparison of the current market of the two light sources. The annual output value of global lighting products is US$42 billion (US$15 billion in China), and the current proportion of LED light sources is less than 1%.
[Edit this paragraph] 7. What is the packaging of LED lights?
LED lamp packaging explanation: Simply put, LED packaging is the process of packaging LED packaging materials into LED lamps; LED lamp packaging process: Generally, LED packaging must go through crystal expansion-crystal bonding-wire bonding-glue filling - Foot cutting, color separation and other processes; LED lamp packaging materials: The main packaging materials of LED are: chips, gold wires, brackets, glue, etc.; LED lamp packaging equipment: crystal expansion equipment, crystal bonding machine, wire bonding machine, point Glue machines, baking ovens, etc. are generally divided into two types: fully automatic packaging equipment and manual packaging equipment.
[Edit this paragraph] 8. How to judge the quality of LED light packaging?
Indicators of the quality of LED lights: Several indicators of the quality of LED lights are: angle, brightness, color (wavelength) consistency, antistatic ability, anti-attenuation ability, etc.; LED light packaging materials : LED packaging material is a direct factor in the quality of LED lights, and it is also the most basic factor. LED lights are a combination of several main materials. A good LED light must be a combination of all packaging materials and production technology; LED light packaging Technology: Generally, fully automatic equipment packaging is better than manual packaging. The technical level of packaging is also the main factor in the quality of LED light packaging. Products produced by different manufacturers of the same materials are very different;
[Edit this paragraph] 9. What kind of LED lights are needed to make LED displays?
Appearance of LED lights: In-line elliptical LED lights are mainly used to make outdoor LED electronic screens, and surface-mounted LED lights are mainly used to make indoor LED electronic screens. Parameters of LED lights: brightness varies according to factors such as the use environment. The wavelength of red light: 620nm-625nm, the wavelength of green light: 520nm-525nm, and the wavelength of blue light: 465nm-470nm.
[Edit this paragraph] 10. LED-Definition
LED (Light Emitting Diode) is a solid-state semiconductor device that can directly convert electricity into light. . The heart of the LED is a semiconductor chip. One end of the light-emitting diode chip is attached to a bracket, one end is the negative electrode, and the other end is connected to the positive electrode of the power supply, so that the entire chip is encapsulated in epoxy resin. The semiconductor wafer is composed of two parts. One part is a P-type semiconductor, in which holes dominate, and the other end is an N-type semiconductor, where electrons are mainly present. But when these two semiconductors are connected, a P-N junction is formed between them. When an electric current acts on this chip through a wire, electrons will be pushed to the P region, where they will recombine with holes, and then energy will be emitted in the form of photons. This is the principle of LED luminescence. The wavelength of light, that is, the color of light, is determined by the material forming the P-N junction. The basic knowledge that semiconductor materials can produce light has been understood for 50 years, and the first commercial diode was produced in 1960.
LED is the abbreviation of light emitting diode in English. Its basic structure is a piece of electroluminescent semiconductor material, placed on a leaded shelf, and then sealed with epoxy resin around to protect the internal core wires. function, so LED has good earthquake resistance. The core part of the light-emitting diode is a wafer composed of p-type semiconductor and n-type semiconductor. There is a transition layer between the p-type semiconductor and n-type semiconductor, which is called a p-n junction. In the PN junction of some semiconductor materials, when the injected minority carriers recombine with the majority carriers, excess energy is released in the form of light, thereby directly converting electrical energy into light energy. When a reverse voltage is applied to the PN junction, it is difficult for minority carriers to be injected, so it does not emit light. This type of diode made using the principle of injection electroluminescence is called a light-emitting diode, commonly known as LED. When it is in the forward working state (that is, forward voltage is applied to both ends), when the current flows from the LED anode to the cathode, the semiconductor crystal emits light of different colors from ultraviolet to infrared. The intensity of the light is related to the current. Initially, LEDs were used as indicator light sources for instruments. Later, LEDs of various light colors were widely used in traffic lights and large-area display screens, producing good economic and social benefits. Take a 12-inch red traffic light as an example. In the United States, a long-life, low-efficiency 140-watt incandescent lamp is used as the light source, which produces 2,000 lumens of white light. After passing through the red filter, the light is lost by 90%, leaving only 200 lumens of red light. In the newly designed lamp, Lumileds uses 18 red LED light sources, which consume a total of 14 watts of power including circuit losses to produce the same light effect. Automotive signal lights are also an important area for LED light source applications. For general lighting, people need white light sources. In 1998, the white-light-emitting LED was successfully developed. This kind of LED is made by packaging GaN chips and yttrium aluminum garnet (YAG). The GaN chip emits blue light (λp=465nm, Wd=30nm), and the YAG phosphor containing Ce3 made by high-temperature sintering emits yellow light after being excited by the blue light, with a peak value of 550nm. The blue LED substrate is installed in a bowl-shaped reflective cavity and covered with a thin layer of resin mixed with YAG, about 200-500nm. Part of the blue light emitted by the LED substrate is absorbed by the phosphor, and the other part of the blue light is mixed with the yellow light emitted by the phosphor to obtain white light. Now, for InGaN/YAG white LEDs, by changing the chemical composition of the YAG phosphor and adjusting the thickness of the phosphor layer, white light of various colors with a color temperature of 3500-10000K can be obtained. This method of obtaining white light through blue LED has a simple structure, low cost, and high technological maturity, so it is the most used. In the 1960s, scientific and technological workers used the principle of semiconductor PN junction to develop LED light-emitting diodes. The material used for the LED developed at that time was GaASP, and its emitting color was red. After nearly 30 years of development, LEDs, which everyone is now very familiar with, can emit red, orange, yellow, green, blue and other colors of light. However, white light LEDs used for lighting have only been developed in recent years. Here we introduce readers to white light LEDs used for lighting. led-introduction 1. The relationship between the visible light spectrum and LED white light. As we all know, the wavelength range of the visible light spectrum is 380nm ~ 760nm, which is the seven colors of light that can be felt by the human eye - red, orange, yellow, green, cyan, blue, and violet. Each of these seven colors of light is A monochromatic light. For example, the peak wavelength of red light emitted by LED is 565nm. There is no white light in the spectrum of visible light, because white light is not a monochromatic light, but a composite light composed of multiple monochromatic lights, just like sunlight is a white light composed of seven monochromatic lights, and the white light in a color TV White light is also synthesized from the three primary colors red, green and blue. It can be seen that in order for an LED to emit white light, its spectral characteristics should include the entire visible spectral range. But it is impossible to manufacture LEDs with this performance under current process conditions.
According to people's research on visible light, the white light that human eyes can see requires a mixture of at least two kinds of light, that is, a two-wavelength light emission (blue light + yellow light) or a three-wavelength light emission (blue light + green light + red light) mode. . The above two modes of white light require blue light, so absorbing blue light has become a key technology for manufacturing white light, that is, the "blue light technology" currently pursued by major LED manufacturing companies. At present, there are only a few manufacturers in the world that have mastered "blue light technology", so the promotion and application of white light LEDs, especially the promotion of high-brightness white light LEDs in our country, still has a long way to go. 2． The process structure and white light source of white LED. For general lighting, in terms of process structure, white LEDs are usually formed using two methods. The first is to use "blue light technology" and phosphors to form white light; the second is to mix multiple monochromatic lights. Both methods have successfully produced white light devices. The first method of producing white light is shown in Figure 1. The LED GaM chip emits blue light (λp=465nm). It is packaged with YAG (yttrium aluminum garnet) phosphor. When the phosphor is excited by blue light, it emits Yellow light, and as a result, blue light and yellow light mix to form white light (the structure that makes up the LED is shown in Figure 2). The second method uses chips of different colors of light to be packaged together, and white light is generated by mixing the colors of light. 3. The application prospects of new light sources for white LED lighting. In order to explain the characteristics of white LEDs, let's first look at the current status of lighting sources. The luminous efficacy of incandescent lamps and tungsten halogen lamps is 12 to 24 lumens/watt; the luminous efficacy of fluorescent lamps and HID lamps is 50 to 120 lumens/watt. For white LEDs: In 1998, the luminous efficacy of white LEDs was only 5 lumens/watt. By 1999, it had reached 15 lumens/watt. This indicator was similar to that of ordinary household incandescent lamps. In 2000, the luminous efficiency of white LEDs was only 5 lumens/watt. It has reached 25 lumens/watt, which is similar to that of tungsten halogen lamps. Some companies predict that by 2005, the luminous efficiency of LEDs will reach 50 lumens/watt, and by 2015, the luminous efficiency of LEDs is expected to reach 150-200 lumens/watt. At that time, the operating current of white LEDs could reach the ampere level. It can be seen that the development of white light LED household lighting sources will become a possible reality. Although incandescent lamps and tungsten halogen lamps used for general lighting are cheap, they have low luminous efficiency (the thermal effect of the lamp consumes electricity in vain), short life, and heavy maintenance workload. However, if white LEDs are used for lighting, not only the luminous efficiency is high, but also the life span is high. Long (continuous working time more than 10,000 hours), almost no maintenance required. At present, the German company Hella has developed aircraft reading lights using white LEDs; a street in Canberra, the Australian capital, has used white LEDs for street lighting; my country's urban traffic management lights are also using white LEDs to replace early traffic order indicators. It is foreseeable that in the near future, white LEDs will enter homes to replace existing lighting lamps. LED light sources have the advantages of using low-voltage power supply, low energy consumption, strong applicability, high stability, short response time, no pollution to the environment, multi-color light emission, etc. Although the price is more expensive than existing lighting equipment, it is still considered to be the future Inevitably existing lighting devices. led-features LED features and advantages The inherent characteristics of LED determine that it is the most ideal light source to replace traditional light sources. It has a wide range of uses. Small size LED is basically a very small chip encapsulated in epoxy resin, so it is very small and very light. Low power consumption LED power consumption is very low. Generally speaking, the working voltage of LED is 2-3.6V. The working current is 0.02-0.03A. That said: it consumes no more than 0.1W. Long service life. Under the appropriate current and voltage, the service life of LEDs can reach 100,000 hours. High brightness, low heat and environmentally friendly LEDs are made of non-toxic materials. Unlike fluorescent lamps that contain mercury, which can cause pollution, LEDs can also be recycled. use. Sturdy and durable LED is completely encapsulated in epoxy resin, which is stronger than light bulbs and fluorescent tubes. There are no loose parts in the lamp body. These features make the LED difficult to damage.
Application of color temperature and color: (1) Color temperature of light source: People use the absolute temperature of a complete radiator that is equal to or similar to the color temperature of the light source to describe the color table of the light source (the color seen when the human eye directly observes the light source), also known as The color temperature of the light source. Color temperature is expressed in absolute temperature K. Different color temperatures will cause people to have different emotional reactions. We generally divide the color temperatures of light sources into three categories: a. Warm light: The color temperature of warm light is below 3300K. Warm light has a similar color to incandescent light and has more red light components. , giving people a warm, healthy and comfortable feeling, suitable for families, residences, dormitories, hospitals, hotels and other places, or places with relatively low temperatures. b. Warm white light: also called intermediate color, its color temperature is between 3300K-5300K. .Warm white light is soft and makes people feel happy, comfortable and peaceful. It is suitable for shops, hospitals, offices, hotels, restaurants, waiting rooms and other places. c. Cold color light: also called daylight color, its color temperature is above 5300K, the light source is close to natural light, it has a bright feeling and makes people concentrate. It is suitable for reading in offices, conference rooms, classrooms, drawing rooms, design rooms, and libraries. rooms, exhibition windows and other places. Color rendering: The degree to which a light source renders the color of an object is called color rendering, which is how realistic the color is. Light sources with high color rendering perform better on colors, and the colors we see are closer to natural colors. Color rendering Low light sources perform poorly on color, and the color deviations we see are larger. Why is there a difference in color rendering? The key lies in the spectroscopic characteristics of the light. The wavelength of visible light is in the range of 380mm to 780mm, which is the red, orange, yellow, green, cyan, and blue we see in the spectrum. , the range of purple light. If the proportion of various colors of light contained in the light emitted by the light source is similar to that of natural light, the colors our eyes see will be more realistic. We generally use the color rendering index to characterize color rendering. Standard colors have a color rendering index of 100 under the radiation of a standard light source. When the color standard is illuminated by a test light source, the degree of visual distortion of the color is the color rendering index of this light source. The greater the color rendering index, the less distortion, and conversely, the greater the distortion, the smaller the color rendering index. Different places have different requirements for the color rendering index of light sources. In the International Lighting Association, the color rendering index is generally divided into five categories: Category Ra Scope of application 1A > 90 Art galleries, museums, printing and other industries and places 2B 80-90 Homes, restaurants, advanced textile technology and similar industries 2 60-80 Offices , schools, outdoor street lighting 3 40-60 heavy industrial factories, outdoor street lighting 4 20-40 outdoor road lighting and some places with low requirements
[Edit this paragraph] 11. Safety regulations of LED lamps Requirements
LED has the advantages of energy saving and environmental protection, and its development in the lighting industry has become a major trend. Since the technology and product attributes used by LEDs are very different from traditional lamps, the current general lamp safety standards are obviously no longer applicable. In order to help the industry face this issue, this issue will explain the technology used in LED lamps, possible application areas, and the safety assessment currently used by UL. LED lamp technology and characteristics The so-called LED lamp, as the name suggests, refers to lamp products that use LED (Light-emitting Diode, light-emitting diode) technology as the main light source. LED is a solid-state semiconductor component that uses current to flow forward to the p-n junction coupling of the semiconductor, and then combines the negatively charged electrons and positively charged holes separated in the semiconductor to generate photons. Emission, different types of LEDs can emit light of different wavelengths from infrared to blue light, and from violet to ultraviolet light. The new development in recent years is to coat blue LEDs with phosphor to convert blue LEDs into white LED products.
This operation generally requires a driver circuit (LED Driver) or power supply (Power Supply). The main function of the driver circuit or power supply is to convert AC voltage into DC power supply, and at the same time complete the voltage and current consistent with the LED. , to drive matching components. The bulbs of LED lamps are small in size, light in weight, and encapsulated in epoxy resin. They can withstand high-strength mechanical shock and vibration, are not easily broken, and have a long brightness decay cycle, so their service life can be as long as 50,000-100,000 hours. , far exceeding the 1,000 hours of traditional tungsten filament bulbs and the 10,000 hours of fluorescent tubes. Since the service life of LED lamps can reach 5 to 10 years, it can not only significantly reduce the cost of lamp replacement, but also has the characteristic of driving light with very small current. With the same lighting effect, the power consumption is only One-half of the fluorescent tube, so LED also has the advantages of saving electricity and energy. However, because some LED technologies are still insufficient, the shortcomings of its initial use in lamps include poor light quality (color rendering, consistency, color temperature), difficulty in heat dissipation, and high price. Improper heat dissipation will cause This leads to accelerated decline in the brightness of LED lamps and the service life of circuit components. With the rapid advancement of manufacturing technology in the past decade, the above-mentioned shortcomings include the gradual reduction of LED thermal resistance and the improvement of light quality. In 2008, in addition to the luminous efficiency of LED white cold light reaching 100 Lm/W, the luminous efficiency of LED warm white light is expected to increase from the current 70 Lm/W to 100 Lm/W in 2010. Compared with other current general light sources, tungsten filament bulbs are about 15 Lm/W, fluorescent fluorescent lamps are about 45~60 Lm/W, and HID lamps are about 120~150 Lm/W. The luminous efficiency of LEDs has obviously become more advantageous; the following are Comparison of lighting properties between LED and other common lamps: Characteristics of lighting methods
White LED has less heat source, wide operating environment, miniaturization, vibration resistance, and concentrated beam
Daylight (fluorescent) Fluorescent lamps save energy, but are fragile and contain mercury contamination.
Incandescent tungsten bulbs are low-efficiency, high-power consumption, short-lived, and fragile
Product Selection Guide Application direction 1. Building exterior lighting to project a certain area of ??the building is nothing more than using round-head and square-head shaped floodlights that control the beam angle, which is completely consistent with the concept of traditional floodlights. However, because LED light sources are small and thin, the development of linear projection lamps has undoubtedly become a highlight of LED projection lamps, because many buildings have no overhanging place to place traditional floodlights. It is easy to install, can be installed horizontally or vertically, and is better integrated with the building surface, bringing a new lighting vocabulary to lighting designers and expanding their creative space. And will have an impact on the lighting techniques of modern architecture and historical buildings. 2. Landscape lighting LED lamp renderings. Because LED is not like traditional lamps whose light sources are mostly glass bulbs, it can be well integrated with urban street furniture. Can be illuminated in urban leisure spaces such as paths, stairs, decks, waterfronts, and gardens. For flowers or low shrubs, LEDs can be used as light sources for lighting. LED hidden floodlights will be particularly popular. The fixed end can be designed as a plug-in type, which can be easily adjusted according to the height of plant growth. 3. In places where signs and indicative lighting need to be space limited and guided, such as separation displays on road surfaces, local lighting on stair steps, and indicator lighting on emergency exits, LED self-luminous underground lights with appropriate surface brightness or embedded lights can be used. Vertical wall lamps, such as ground guide lights in theater auditoriums or indicator lights on the side of seats, and guide lights on floors in shopping malls, etc. In addition, compared with neon lights, LEDs are low-voltage, do not have fragile glass, and will not increase costs due to bending during production. They are worthy of promotion and use in logo design.
4. In terms of lighting quality for indoor space display lighting, since LED light sources have no heat, ultraviolet and infrared radiation, they will not cause damage to exhibits or commodities. Compared with traditional light sources, lamps do not require additional filtering devices, and the lighting system is simple and low-cost. Inexpensive and easy to install. Its precise lighting can be used as an alternative to fiber optic lighting in museums. Most commercial lighting uses colored LEDs. Indoor decorative white LEDs are combined with interior decoration to provide auxiliary lighting indoors. LEDs can be used in hidden light strips, which is particularly beneficial for low spaces. 5. Entertainment venues and stage lighting Due to the dynamic and digital control of color, brightness and dimming of LEDs, lively saturated colors can create static and dynamic lighting effects. From white light to any color in the full spectrum, the use of LEDs opens up new ideas in the lighting of such spaces. Long life and high lumen maintenance value (90% luminous flux is maintained after 10,000 hours), compared with the 50-250 hours life of PAR lamps and metal halide lamps, reduces maintenance costs and the frequency of light source replacement. In addition, LED overcomes the phenomenon of color shift of metal halide lamps after being used for a period of time. Compared with PAR lights, there is no heat radiation, which can make the space more comfortable. At present, the application of LED colorful decorative walls in catering buildings has become a common practice. 6. Video screen The full-color LED display is the most eye-catching large-scale outdoor display device in the world today. It uses advanced digital video processing technology and has unparalleled large area and ultra-high brightness. According to different indoor and outdoor environments, various specifications of luminescent pixels are used to achieve different brightness, color, and resolution to meet various purposes. It can dynamically display graphics, text and animation information, and utilize multimedia technology to play various multimedia files. The most influential LED display in the world is undoubtedly the New York Stock Exchange in Times Square, Manhattan, USA. It uses a total of 18,677,760 LEDs and covers an area of ??10,736 square feet. The screen can be divided into multiple screens and displayed simultaneously, presenting the Wall Street stock market conditions to the public at a glance. In addition, the Aurora International Headquarters, which rises in the Lujiazui Financial Center in Pudong, Shanghai, has a 100m-long super-large LED screen on the entire facade facing Puxi, with a total area of ??3,600 square meters. It can be called the best in the world. 7. Vehicle indicator lighting is suitable for the lighting of electric vehicles, motorcycles and car lights
[Edit this paragraph] 12. The LED light power supply determines the life of the LED light
Hang Current source driving is the best LED driving method. It adopts constant current source driving. There is no need to connect a current limiting resistor in series with the output circuit. The current flowing through the LED is not affected by changes in external power supply voltage, ambient temperature, and discreteness of LED parameters. , so that the current can be kept constant and the various excellent characteristics of LED can be fully utilized. An LED constant current power supply is used to power LED lamps. Since the current flowing through the LED is automatically detected and controlled during operation of the power supply, there is no need to worry about excessive current flowing through the LED at the moment of power-on, or a load short circuit and burnout. Bad power supply