The wide application of LED technology in the 2010 Shanghai World Expo has attracted people's attention. At present, the world's energy is tight, and finding and solving energy problems in the future world has become a top priority. Since the advent of high-brightness white LEDs, it has been characterized by high luminous efficiency, good power saving effect, low energy consumption, safety, low heat, no pollution, long life and excellent economy. It is not only used in lighting, but also in military products and other. Widely used in technology products. The service life of LED lighting is about 80-100,000 hours, and in the case of the same brightness, the power consumption of LED lamps is 1/8 of that of incandescent lamps. It can be predicted that LED will be widely concerned and promoted and applied around the world. At present, the Chinese government is vigorously promoting high-efficiency and energy-saving products, and fully implements the system of government priority and compulsory procurement of energy-saving products. Therefore, it is necessary to explore the application technology of LED lighting.
1 Introduction
LED (Light Emitting Diode), a new modern product component for modern voice control, light control and time control, is a leading product in modern development and a new generation of components in the modern future. It is a semiconductor device that can directly convert electricity into light. It relies on the combination of positive and negative charges in the material to illuminate.
The intrinsic characteristics of the LED determine that it is the most ideal light source to replace the traditional light source, and it has a wide range of (green) new generation components.
2. LED performance characteristics:
2.1 Energy-saving safety (components that modern new energy will replace)
The LED uses a low-voltage power supply. The operating voltage of the general LED is 2-3.6V, the operating current is 0.02-0.03A, and the power consumption of the electric power does not exceed 0.1W. It is an electrical appliance that is safer than using a high-voltage power supply. It has been used on indicator appliances in various public places.
2.2 High brightness, low heat
A light source that measures the brightness of traditional bulbs and is more adjustable and controllable. The power consumption is about 30% of the average bulb, even less than the HID or incandescent bulbs. Safety performance increased by 200%.
2.3 Applicability and small size
LED is basically a small chip packaged in epoxy resin, so it is very small, very light, suitable for a variety of environments, it can also be applied to modern military and technology products.
2.4 Long service life
At the right current and voltage, LEDs can last up to 100,000 hours.
2.5 stable performance
Can work normally for 80,000 to 100,000 hours.
2.6 Short response time
The response time of a normal lamp is milliseconds, and the response time of an LED lamp is nanometer.
2.7 Environmental protection
LEDs are made of non-toxic materials. Unlike mercury-containing fluorescent lamps, they can cause pollution and contain no harmful substances such as mercury. The heat radiation is rare, and LEDs can be recycled.
2.8 Rugged and durable, good shock resistance
It has stronger seismic performance than traditional lamps and is more suitable for and meets the installation requirements of various occasions. The LED is completely encapsulated in epoxy, which is stronger than both the bulb and the fluorescent tube. There are no loose parts in the lamp body. These features make the LED a new component that is not easily damaged.
2.9 Beam concentration
2.10 The calorific value is very small
The heat resistance of the luminaire material is very high.
2.11 Strong controllability
Various color changes can be achieved. It is a modern component of various products, and is applied to new products replaced by new components of sound control, light control and time control.
3. Classification of LED chips
3.1 According to the brightness of the light:
A. General brightness: R, H, G, Y, E, etc.
B. High brightness: VG, VY, SR, etc.
C. Ultra high brightness: UG, UY, UR, UYS, URF, UE, etc.
D. Invisible light (infrared): R, SIR, VIR, HIR
E. Infrared receiving tube: PT
F. Photocell: PD
3.2 By special category:
A. Infrared light (invisible light)
B. Infrared receiving tube
C. Photocell
3.3 LED wafers need to pay attention to in production and use
LED use conditions:
The power of the LED ranges from 0.005W to 1W and even from 3W to 4.5W. Therefore, LED work needs to meet two conditions:
A. Forward voltage V1 ≤ 3.4V.
B. Forward current I ≥ 20 mA. Generally 20 mA to 1 A.
LEDs should pay attention to the protection of static electricity during production or use.
4. Use of LED
4.1 Replacement of cold cathode fluorescent lamps (CCFT) with white LEDs for backlighting of small LCD color screens.
Since the white LED is driven by a simple circuit, does not require a positive and negative power supply, and has high efficiency and small size, it is widely used in portable electronic products. With the improvement of the performance of white LEDs, the application of white LEDs as backlights is not only used in small color screen electronic products such as mobile phones, game consoles, PDAs, MP4s, digital cameras, etc., but has been applied to DVDs, GPSs and 15-inch screens with larger screen sizes. In the laptop. It has become one of the largest users of LEDs, accounting for about 30% of the annual LED production.
4.2 Use white LEDs as flashlights for compact digital cameras to replace traditional xenon lamps.
Since the short-time pulse is used to power the LED, it can be twice as large as the rated current, and the strong light can meet the requirements of the camera fill light. The circuit that drives the LED flash does not require a high-voltage power supply, and does not have the disadvantage of charging for a long time, and can obtain more opportunities for capturing and making the battery last longer. The demand for higher usage of the product.
4.3 A true green lighting system consisting of solar cells, batteries and white LEDs.
China's solar cell production is very large, reaching 370MW in 2006, and the production capacity of solar modules has exceeded 1000MW. This creates extremely good conditions for lighting white LED lights with solar energy. This is not only used in the no-electric zone, but also in the towns (in foreign countries, mainly relying on a large number of installed roof-connected systems to develop the solar photovoltaic industry). At present, China has been able to produce a complete set of white LED lighting systems suitable for people in pastoral areas. In some cities, solar cells, batteries and light control circuits are also used to form LED street lights, which can be automatically lit in the dark and turned off.
It is ideal to use solar energy to convert electricity into electric energy instead of thermal power generation, but the large-scale application of solar energy is a large system engineering. Although China has been able to produce a large number of solar cells, it is a pity that 95% is used for export, leaving only 5% for domestic applications. At present, the use of solar energy to illuminate LED lights is still in its infancy. The application of the Shanghai World Expo has attracted the attention of our scientific and technical personnel.