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LED status

Source: RUI JIN

2018-04-01 08:29:28

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In the 1990s, LED technology made great progress. Not only did the luminous efficiency exceed that of incandescent lamps, the light intensity reached the candlelight level, but also the color ranged from red to blue to cover the entire visible spectrum. From the indicator level to more than universal The technological revolution at the level of light sources has led to a variety of new applications, such as automotive signal lights, traffic lights, outdoor full-color large displays, and special lighting sources.

Light-emitting diode applications:
With the advancement of high brightness and multicolorization of light emitting diodes, the application field is also expanding. From the lower luminous flux indicator to the display, and then from the outdoor display to the medium luminous flux power signal lamp and special illumination white light source. Developed into the upper right corner of the high luminous flux general illumination light source. 2000 is the dividing line of time. In 2000, the signal display problems and lighting problems of all colors have been solved, and low and medium luminous flux special lighting applications have begun, and as general lighting The application of high-light flux white light lighting seems to take a long time, and the light flux needs to be further greatly improved. Of course, this is a process that will be gradually realized with the increase of brightness and the decrease of the price.

LED display
Since the mid-1980s, monochrome and multi-color displays have been available, initially as text screens or animated screens. In the early 1990s, the development of computer technology and integrated circuit technology led to the realization of video technology for LED displays. TV images directly on the screen, especially in the mid-90s, blue and green ultra-high brightness LED successfully developed and quickly put into production, so that the application of outdoor screens is greatly expanded, ranging from 100-300m. LED display screens are currently in the stadium, Squares, conference halls, even streets and shopping malls have been widely used. The Nasdaq full-color screen on Times Square in the United States is best known. The screen area is 120 feet by 90 feet, which is equivalent to 1005 meters. It consists of 19 million ultra-bright blue and green. , Red LED made. In addition, the application in the securities market screen, bank exchange rate screen, interest rate screen, etc. also accounted for a large proportion of the recent development in the information screen of highways, elevated roads. LED in this The application of the field has become a scale, emerging industries, and can expect a more stable growth.

2. Traffic lights
The navigation light has used LED as the light source for many years, and the current work is to improve and perfect it. The road traffic signal light has made great progress in recent years, rapid technological development, rapid application development, China currently has about 40,000 sets of orders each year. In the United States last year, California used LED traffic lights to replace 50,000 sets of signals of traditional light sources. According to the results, long life, power saving, and maintenance-free effects are obvious. The current LED peak wavelength is red 630nm. , Yellow 590nm, Green 505nm. Should pay attention to the problem is that the drive current should not be too large, otherwise the high temperature conditions in the summer sun will affect the life of the LED.
Recently, the LED airport special signal lamps used in airports as standard lights, spotlights and omnidirectional lights have also been successfully used and put into use. Many parties have achieved good results. It has independent intellectual property rights and has obtained two patents with good reliability. , Save electricity, maintenance-free, can be applied to a variety of airports, replace the old signal lights that have been used for decades, not only high brightness, but also because of the LED light color purity, especially bright, easy signal recognition.
Because of the large variety of series of signals used in railways, the required light intensity and viewing angle are also different. At present, research and development is being stepped up. It is estimated that it will gradually be successfully developed and gradually put into use. In terms of quantity, it is also a large market.

3. Car lights
Super bright LED can be made into the car's brake lights, taillights, and direction lights. It can also be used for instrument lighting and interior lighting. It has obvious advantages over incandescent lamps in terms of shock resistance, power saving and long life. It is used as a brake light. Its response time is 60ns, which is much shorter than the 140ms of incandescent lamps. Driving on a typical highway will increase the safety distance by 4-6m.

4. LCD backlight
LED is used as the backlight of liquid crystal display. It can not only be used as green, red, blue, white, but also as a color-changing backlight. Many products have already entered the production and application stage. Recently, LCDs on mobile phones have been used to make backlights. Enhance the product's grade, the effect is very good. The use of 8 blue, 24 green, 32 red LuxeonLED 15in (1in ≈ 2.5cm) LCD backlight can reach 120W, 2500 lm, brightness 18000nits (nit, cd/m2) .22 LCD backlight has also been made, only 6mm thick, not only good color mixing, color rendering index also reached 80 or more. Although the current large-scale backlight is in the development stage, but has great potential .

5. Lighting
Due to the increase in brightness and price of light-emitting diodes, coupled with long life, saving electricity, driving and control than the neon light, not only can flash, but also change color, so made with ultra-high brightness LED monochrome, multi-color and even The color-changing light-emitting columns are combined with light-emitting units of other shapes, and the landscape works of tall buildings, bridges, streets, and squares are well-exposed, presenting a variety of colors, flashing stars, and brilliance. Many units have produced LEDs. More than 10,000 meters of light beam, tens of thousands of lanterns, is currently being gradually promoted, it is estimated that will gradually expand the formation of a separate industry.

6. Lighting source
LED light source as lighting source should be white light, white light LED light source classification as shown in Table 3. At present, as a military white LED lighting fixture, some varieties have been put into mass production. Because LED light source has no infrared radiation, it is easy to conceal, plus it also With the advantages of resistance to vibration, suitable for battery power supply, solid structure and easy to carry, etc., there will be greater development in special lighting sources. As a civilian use, lawn lamps and buried lights have been produced on a scale, but also used as a microscope Field lighting, flashlights, headlights of surgeons, lighting of museums or exhibitions, and reading lamps. With the increase of luminous flux and price reduction, the application area will gradually expand to complete the transition from special lighting to general lighting. Estimate 2005-2010 The annual meeting entered the general lighting field.