24 May

LED energy-saving lamp development history

Posted By: John Times Read: 63

LED energy-saving lamps are a new generation of illumination sources after compact fluorescent lamps (ie, ordinary energy-saving lamps).

An LED, a semiconductor light-emitting diode, is a solid-state semiconductor device that directly converts electricity into light. LED energy-saving lamp is a high-brightness white LED light source with high luminous efficiency, low power consumption, long life, easy control, maintenance-free, safe and environmental protection. It is a new generation of solid cold light source with soft, colorful, colorful and low light color. Loss, low energy consumption, green and environmental protection, suitable for long-term lighting in homes, shopping malls, banks, hospitals, hotels, restaurants and other public places. No flash DC, it has a good protection for the eyes, it is the best choice for desk lamps and flashlights.

Light-emitting diode, the heart of the LED is a semiconductor wafer. One end of the chip is attached to a bracket, one end is a negative pole, and the other end is connected to the positive pole of the power source, so that the entire wafer is encapsulated by epoxy resin. The semiconductor wafer consists of two parts, one part is a P-type semiconductor, in which the hole dominates, and the other end is an N-type semiconductor, which is mainly electrons here. But when the two semiconductors are connected, they form a P-N junction. When a current is applied to the wafer through the wire, the electrons are pushed toward the P region. In the P region, the electrons recombine with the holes, and then the energy is emitted in the form of photons. This is the principle of LED illumination. Because the LED lamp does not generate heat, the electric energy is converted into light energy as much as possible, and the ordinary lamp converts a lot of electric energy into heat energy due to the heat generation, which is wasted. In contrast, LED lighting is energy efficient.

LED energy-saving lamps are a category of LED general-purpose lighting, and their names are derived from traditional lighting bulbs and energy-saving lamps. The shape of the LED energy-saving lamp is similar to that of the traditional energy-saving lamp, and the shape can satisfy the traditional aesthetics of the consumer. The characteristics of LED energy-saving lamps: low cost, high luminous efficiency, large luminous area, no glare, no ghosting.

History development

In the 1960s, people learned about the basics of semiconductor materials that produced light. The first commercial diode was born in 1960.

LED is the abbreviation of English light emitting diode. Its basic structure is an electroluminescent semiconductor material placed on a leaded shelf and then sealed with epoxy resin to protect the inner core. The role, so the LED's seismic performance is good.

The core of the LED is a wafer consisting of a p-type semiconductor and an n-type semiconductor. There is a transition layer between the p-type semiconductor and the n-type semiconductor, called a p-n junction. In some PN junctions of semiconductor materials, the injected minority carriers recombine with the majority carriers to release excess energy in the form of light, thereby directly converting electrical energy into light energy. The PN junction is added with a reverse voltage, and minority carriers are difficult to inject, so they do not emit light. Such a diode fabricated by the principle of injection electroluminescence is called a light-emitting diode, and is generally called an LED. When it is in the forward working state (ie, the forward voltage is applied to both ends), when the current flows from the anode of the LED to the cathode, the semiconductor crystal emits light of different colors from ultraviolet to infrared, and the intensity of the light is related to the current.

The LED was originally used as an indicator light source for instrumentation. Later, various light-colored LEDs were widely used in traffic lights and large-area displays, resulting in good economic and social benefits. Take the 12-inch red traffic light as an example. In the United States, a long-life, low-efficiency 140-watt incandescent lamp was used as the light source, which produced 2000 lumens of white light. After passing the red filter, the light loss is 90%, leaving only 200 lumens of red light. In the newly designed lamp, Lumileds used 18 red LED light sources, including circuit losses, to consume 14 watts of electricity, which would produce the same light effect. Automotive signal lights are also an important area for LED light source applications.

For general lighting, people need a white light source. In 1989, white LEDs were successfully developed. This LED is made by encapsulating a GaN chip and yttrium aluminum garnet (YAG). The GaN chip emits blue light (λp=465 nm, Wd=30 nm), and the Ce3+-containing YAG phosphor prepared by high-temperature sintering is excited by the blue light to emit a yellow light with a peak of 550 nm. The blue LED substrate is mounted in a bowl-shaped reflective cavity covered with a thin layer of resin mixed with YAG, about 200-500 nm. The blue portion of the LED substrate is absorbed by the phosphor, and the other portion of the blue light is mixed with the yellow light emitted by the phosphor to obtain white light. For the InGaN/YAG white LED, by changing the chemical composition of the YAG phosphor and adjusting the thickness of the phosphor layer, white light of various colors having a color temperature of 3500 to 10000 K can be obtained.

This method of obtaining white light by a blue LED has the advantages of simple structure, low cost, and high technical maturity, and thus is most used.

In the 1960s, scientists and technicians developed LED light-emitting diodes using the principle of semiconductor PN junction light. The LED used at that time was made of GaASP, and its luminescent color was red. After nearly 30 years of development, LEDs that are very familiar to everyone have been able to emit red, orange, yellow, green, blue and other colors. However, the white LEDs used for lighting have only developed in the past two years. Here, readers are introduced about white LEDs for lighting.

LED introduction

LED energy-saving lamps are a new generation of illumination sources after compact fluorescent lamps (ie, ordinary energy-saving lamps).

Compared with ordinary energy-saving lamps, LED energy-saving lamps are environmentally friendly and contain no mercury. They can be recycled and reused. They have low power, high luminous efficiency and long life. They are open and bright, resistant to frequent switching, low light decay, rich in color, dimmable, and rich in change. . The extensive use of ordinary energy-saving lamps will cause mercury pollution, pollute the soil water source, and indirectly pollute food, and the environmental hazards should not be underestimated.

development path

- Industrial lighting technology plays a leading role and a supporting role in the IT and BIO revolutions;

- LED is the new light of the 21st century, its application and research and rapid development;

- LED technology in Korea and East Asia leads the world market (70% of the world market);

- The huge wave of LED technology will be the second revolution in the history of human lighting;

- In the next five years, LED technology will move towards the replacement of white heat lamps, fluorescent lamps and halogen lamps.

- In 2010, LED lights accounted for 16% of the world's lighting market.

Lighting memorabilia

- 1879 Edison invented the electric light;

- 1938 fluorescent lamps are available;

- 1959 halogen lamp is available;

- 1961 high pressure sodium lamp came out;

—1962 metal halide lamp;

—1969 The first LED light (red);

—1976 green LED light;

—1993 blue LED light;

—1999 white LED light;

—2000 LEDs are used in indoor lighting.

The development of LED is the second revolution in the 120 years since the development of white heat lighting.

- At the beginning of the 21st century, LEDs developed through the wonderful encounter between nature, humans and science will become the innovation of the light world, the green technology light revolution essential to mankind.

—LED will be a renewed light revolution since Edison invented the light bulb.

—LED will be a renewed light revolution since Edison invented the light bulb.

LED lighting is mainly based on high-power white LED single lamp. The world's top three LED lighting manufacturers are guaranteed for three years. Large particles are greater than or equal to 100 lumens per watt, and small particles are greater than or equal to 110 lumens per watt. Light decay large particles are less than 3% per year, and light decay small particles are less than 3% per year.

LED solar street lights, LED flood lights, LED ceiling lights, and LED fluorescent lamps are already in mass production. For example, a 10 watt LED fluorescent lamp can replace a 40 watt ordinary fluorescent lamp or an energy saving lamp.

More and more led energy-saving lamps have entered the ordinary people's home, but not yet popular!

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