Application of LED light source in landscape lighting

LED light source is generally called the fourth generation illumination source or green light source, which has the characteristics of high energy saving, environmental protection, long life, small size and many changes. The LED light source is a light source that uses a light emitting diode as an illuminant. LED lighting products are lighting fixtures that use LEDs as light sources.

1 Basic characteristics of LED and precautions during use

1. 1 Photoelectric characteristics

The greater the current that the LED flows through the LED over its current limit parameter, the higher its luminance. That is, the brightness of the LED is proportional to the current through the LED. However, green light, blue light and white light will saturate under high current conditions, which not only greatly reduces the luminous efficiency, but also shortens the service life.

1. 2 optical characteristics

LEDs are available in red, orange, yellow, green, blue, purple, and white. According to the brightness, there are bright, bright, super bright, etc. The same kind of chip has different brightness in different packaging modes. According to human vision, it can be divided into visible light and invisible light. According to the color of the illuminating color, it can be divided into various types such as monochrome, two-color, and colorful. The purity of the colors is different, the prices vary greatly, and the current pure white LEDs are extremely expensive. At the same time, the light-emitting angles are different, and the light effects are different. Pay special attention when using them.

1. 3 common LED electrical performance parameters

1) LED forward voltage. Different color LEDs have different forward voltage drop values ​​under rated forward current conditions, red and yellow: 1. 8 V~ 2. 5 V, green and blue: 2. 7 V~ 4 Between 0 V. For LEDs of the same color, the forward voltage drop and light intensity are not exactly the same. 2) The rated operating current of the LED. LEDs have different current ratings. Normal LED currents are typically 20 mA, and high-power LED currents typically range from 40 mA or 350 mA. Specifically, it should be selected according to the current parameter values ​​provided by each package factory. In general, the LED has a reverse current of IR 10 A under the condition of a reverse voltage of VR = 5 V. 3) The power of the LED. The LED power is also different, with 70 mW, 100 mW, 1 W, 2 W, 3 W, 5 W, etc., so it is necessary to design a reasonable use of the circuit and configure the appropriate number of LEDs according to the selected LED. It fully meets the rating of the LED power supply.

1. 4 Temperature characteristics

1) The soldering temperature of the LED should be below 250, and the soldering time should be controlled between 3 s and 5 s. Care should be taken to avoid damage to the chip due to excessive LED temperature. 2) The brightness output of the LED is inversely proportional to the temperature. The temperature not only affects the brightness of the LED, but also affects its lifetime. Minimize circuit heating during use and do some heat dissipation.

1. 5 anti-static characteristics

Anti-static measures must be strengthened during LED assembly, because the operation process and the human body itself generate static electricity. For the two-electrode LED, it is most likely to be reversely broken by static electricity, which seriously affects the service life of the LED and even completely eliminates it. If the anti-static environment is not perfect, you can add an anti-static wrist strap to the LED user, set up a good anti-static grounding system, ion fan and other equipment. Due to these characteristics, LEDs are now widely used in a variety of indications, displays, decorations, backlights, general lighting and urban night scenes. The typical use of LEDs is display screens and indicator lights. The technology used for decorative purposes is also mature. It is widely used in signage and light sculptures. LEDs are gradually replacing traditional Mind-resistant lamps.

2 LED application in landscape lighting

1) Energy saving and environmental protection. a. High luminous efficiency: In terms of energy saving, after several decades of technical improvement, LED's luminous efficiency has been greatly improved. Moreover, its light has good monochromaticity and narrow spectrum, and it can directly emit colored visible light without filtering. At present, countries all over the world are stepping up research on LED light efficiency, and their luminous efficiency will be greatly improved in the near future. b. Low power consumption: LED single tube power 0. 03 W~ 0. 06 W, DC drive, single tube drive voltage 1. 5 V~ 3. 5 V, current 15 mA~ 18 mA, its electro-optical power conversion Close to 100%, fast response, high frequency operation. The energy conversion efficiency of LED light source is very high. The same lighting effect is more than 80% energy saving than traditional light source. The brightness of a 50 W energy-saving lamp can be equivalent to that of 300 W~400 W high-pressure sodium lamp, and the light life is increased by more than 10 times, while the electricity cost is To reduce by nearly 90%. The energy-saving effect is remarkable, which is undoubtedly of great significance to China, where energy is very tight. It has better environmental benefits, no ultraviolet and infrared rays in the spectrum, no heat, no radiation, little glare, and waste can be recycled, no pollution, no mercury, cold light source, safe touch, typical Green lighting source.

2) Long life. The service life of LED lamps can reach 5 to 10 years, which can greatly reduce the maintenance cost of lamps and avoid the pain of frequent lamp replacement. More than 10 times longer than traditional light sources. Under normal circumstances, the use of LEDs, the light fade can be reduced to 70% of the nominal life of 100,000 h, reducing the frequency of replacement and other maintenance work.

3) The light color is pure. Since typical LEDs have a narrow spectral range, they do not have the full spectrum like incandescent lamps. Therefore, LEDs can be arbitrarily combined in a variety of ways, especially for decoration and other aspects.