The development of LED

- May 24, 2019-

To general illume character, people needs white illuminant more. 1998 white LED onSend a success. The LED is made of GaN chip and yttrium aluminum garnet (YAG) encapsulated together. GaN chip emitting blue light (lambda p =465nm, Wd=30nm), high-temperature sintered YAG phosphors containing Ce3+ emit yellow light after stimulated by this blue light, with a peak value of 550nm. The blue LED substrate is mounted in a bowl-shaped reflecting chamber and covered with a thin layer of resin mixed with YAG, about 200-500nm. Part of the blue light from the LED substrate is absorbed by the phosphor, and part of the blue light is mixed with the yellow light from the phosphor to get white light. For InGaN/YAG white LED, white light with color temperature of 3500-10000k can be obtained by changing the chemical composition of YAG phosphor powder and adjusting the thickness of phosphor powder layer.

Blue light LED technology, in short, is a more energy efficient way to generate light, but also can be applied to cameras, mobile phones and other technology products. Lighting made with blue LED technology is more energy efficient and significantly reduces the amount of energy used on the planet. According to the existing data, 25% of the world's electricity is used for lighting, but with LED lamps, the electricity used for lighting is reduced to 4%, which undoubtedly changes the whole world.

From the discovery of LED effect in 1907 to the official invention of LED by shuji nakamura in 1993, to the official commercial use of 1W LED lamp in 1999, LED experienced nearly a hundred years of development. Until then, people had been using incandescent light bulbs, invented by Thomas Edison in the last century. Incandescent light bulbs waste most of their energy in heat, and about 90 percent of their electricity is wasted.

The appearance of LED lamps has greatly reduced the power required for lighting. The same wattage of LED lamps requires only 1/10 of the power of incandescent bulbs. At the same time, LED has the advantages of long life, environmental protection and maintenance-free. In 2012, the Chinese government announced a total ban on the sale and import of incandescent lamps with over 100 watts for general lighting.

As the Nobel Prize in physics put it: "incandescent light bulbs illuminate the 20th century, while leds will illuminate the 21st."

advantage

1. High efficiency and energy saving

It only consumes a few kilowatt-hours for a thousand hours (ordinary 60W incandescent lamp consumes 1 kilowatt-hour for 17 hours and ordinary 10W energy-saving lamp consumes 1 kilowatt-hour for 100 hours)

2. Long life

Semiconductor chip luminescence, no filament, no glass bubble, not afraid of vibration, not easy to break, the service life of up to 50,000 hours (the service life of ordinary incandescent lamp is only 1,000 hours, the service life of ordinary energy-saving lamp is only 8,000 hours)

3, good health,

Light healthy light contains no ultraviolet and infrared rays and does not emit radiation (ordinary light rays contain ultraviolet and infrared rays)

4. Green and environmental protection:

Free of harmful elements such as mercury and xenon, it is easy to recycle and clean, and does not cause electromagnetic interference (mercury and lead are contained in ordinary lamps, and electronic ballasts in energy-saving lamps can cause electromagnetic interference).

Protect your eyesight

Dc drive, no stroboflash (common lamps are ac drive, so stroboflash is inevitable)

6. High light efficiency

10% less heat is converted into visible light (95% of the electricity in an ordinary incandescent bulb is converted into heat, and only 5% into light).

7. High safety factor

The required voltage and current are small, and the heat is small, so there is no potential safety hazard

8. Great market potential

Low voltage, dc power supply, battery, solar power supply, in remote mountainous areas and outdoor lighting places, such as power shortage.

contrast

1. LED lights will have stroboscopic phenomenon just like ordinary incandescent lamps when driven by alternating current, while ordinary energy-saving lamps have no stroboscopic phenomenon. Strobe causes eye strain.

2, the light of each LED bulb is too bright, will strongly stimulate the eyes, can not look straight at, even for a short time, and ordinary energy-saving light relatively soft!

3, illuminate Angle has a limit, normally only illuminate is 120 °, and ordinary energy-saving lamps to illuminate almost 360 °.

4. The brightness of the room is no better than that of the energy-saving lamp, because the led only has a high brightness in the narrow Angle of direct vision, and the light quickly weakens after deviating from this Angle.

Therefore, the advantages of LED energy-saving lamps as indoor lighting lamps may not be more obvious than ordinary energy-saving lamps, but as torches, table lamps, spotlights, etc. only need to illuminate the narrow Angle of the lamps or use is very excellent.

The choose and buy

1. LED brightness (MCD) varies with different prices. Used for led lamps and lanterns, the led should comply with the laser level Ⅰ class standard.

2, anti-static ability of anti-static ability of LED, long life, and therefore high price. Usually antistatic is greater than

Only 700V LED can be used for LED lighting.

3, the same wavelength of LED, color is consistent, if the color is consistent, the price is high. It is difficult for manufacturers to produce pure color products without LED spectrocolorimeter.

4, leakage current LED is unidirectional conductive luminous body, if there is a reverse current, it is called leakage, leakage current large LED, short life, low price.

5, the luminous Angle of different USES of LED lighting Angle is not the same. Special luminous Angle, higher price. If full diffuse Angle, the price is higher.

6, life is the key to different qualities of life, life is decided by the decline of light. Light decline small, long life, long life, high price.

7. The luminescent body of chip LED is a chip, and the price varies greatly among different chips. Chips from Japan and the United States are more expensive, while those from Taiwan and China are generally cheaper than those from Japan and the United States (CREE).

The size of the chip is indicated by the side length. The quality of the large chip LED is better than that of the small chip. The price is proportional to the size of the chip.

9. Colloid the colloid of ordinary LED is generally epoxy resin, and the LED with anti-ultraviolet and fireproofing agent is relatively expensive. High-quality outdoor LED lighting should be anti-ultraviolet and fireproofing. Each product will have a different design, different design is suitable for different purposes, LED lighting reliability design includes: electrical safety, fire safety, applicable environmental safety, mechanical safety, health safety, safety use time and other factors. From the point of view of electrical safety, should comply with the relevant international and national standards.