Electric lamp, that is, an artificial lighting appliance that uses electricity as energy to convert electric energy into light energy and illuminate human beings in darkness or darkroom. Since the invention of electric light, it has greatly promoted the development of mankind.
First of all, incandescent lamps
(incandescent lamp)
1. Ordinary incandescent lamps are commonly used incandescent bulbs.
Features: Good color rendering (Ra= 100), bright lights, continuous dimming, simple structure, low price, short service life and low light efficiency.
Uses: living room, living room, lobby, guest room, shop, restaurant, walkway, conference room, courtyard.
Uses: table lamp, ceiling lamp, wall lamp, bedside lamp, corridor lamp.
Second, halogen tungsten lamp
(tungsten halogen lamp)
Inflatable incandescent lamp, the filling gas contains some halogen elements or halides. It has all the characteristics of ordinary lighting incandescent lamp, the light efficiency and service life are more than twice as long as those of ordinary lighting incandescent lamp, and the volume is small.
Uses: special lighting for conference rooms, exhibition halls, living rooms, commercial lighting, film and television stages, instruments, automobiles, airplanes, etc.
Third, gas discharge lamps.
(discharge lamp)
1. Low pressure discharge lamp (1) fluorescent lamp (1)
Fourth, fluorescent lamps.
(commonly known as fluorescent lamp)
Features: high light efficiency, long life and good light color.
Fluorescent lamps are straight tube type, ring type and compact type. It is a widely used energy-saving lighting source.
Using straight fluorescent lamp instead of incandescent lamp can save electricity by 70~90% and prolong life by 5~ 10 times.
Upgrade the straight fluorescent lamp to save electricity15 ~ 50%;
Replacing incandescent lamp with compact fluorescent lamp can save electricity by 70~80% and prolong life by 5~ 10 times.
Five, high intensity gas discharge lamp
(high intensity discharge lamp)
High intensity gas discharge lamps include fluorescent high pressure mercury lamps, high pressure sodium lamps and metal halide lamps.
(1) fluorescent high-pressure mercury lamp
Features: Long service life and relatively low cost.
Uses: road lighting, indoor and outdoor industrial lighting, commercial lighting.
(2) High pressure sodium lamp
Features: long service life, high light efficiency and strong fog permeability.
Uses: road lighting, floodlighting, square lighting, industrial lighting, etc.
(3) Metal halide lamps
Features: long life, high luminous efficiency and good color rendering.
Uses: industrial lighting, urban lighting, engineering lighting, commercial lighting, stadium lighting and road lighting.
(4) ceramic metal halide lamp
Features: The performance is superior to that of general metal halide lamps.
Uses: Shopping mall, window, key display and commercial street lighting.
(5). Low pressure sodium lamp
Features: high luminous efficiency, long service life, high luminous flux retention rate, strong fog permeability, but poor color rendering.
Uses: Lighting for tunnels, ports, docks and mines.
Six, high frequency electrodeless lamp
(electrodeless lamp)
Features: long service life (40,000 ~ 80,000 hours), energy saving, no electrode, instant start and restart, no stroboscopic, good color rendering.
Uses: public buildings, shops, tunnels, pedestrian streets, high-pole street lamps, security lighting and other outdoor lighting.
Seven, halogen bulbs
Halogen lamp, also known as tungsten halogen lamp, is a kind of incandescent lamp. The principle is to inject halogen gas such as iodine or bromine into the bulb. At high temperature, the evaporated tungsten wire reacts chemically with halogen, and the evaporated tungsten will solidify again on the tungsten wire to form a balanced cycle to avoid premature fracture of the tungsten wire. Therefore, halogen bulbs last longer than incandescent lamps. In addition, halogen bulbs can work at a higher temperature than ordinary incandescent lamps, with higher brightness and efficiency. However, at this temperature, ordinary glass may soften. Therefore, halogen bulbs need to use timely glass with higher melting point. Because timely glass can't block ultraviolet rays, halogen bulbs usually need to use additional ultraviolet filters. If there is oil in the crystal glass on the halogen bulb, it will cause different temperatures on the glass and reduce the life of the bulb. Therefore, when replacing halogen bulbs, people should avoid touching the glass of the bulbs.
Eight, tungsten lamp
The development of tungsten wire industry has been closely linked with the light bulb industry from the beginning.
1878, Edison invented the carbon filament light bulb. But this kind of light bulb has serious shortcomings, mainly because its life is too short. After nearly 20 years (1897), carbon wire was replaced by osmium wire and tantalum wire, but the working temperature and light efficiency were low because of the low melting points of Os and Ta.
1903, according to the patents of A. Just and F. Hannaman, Hungary made tungsten wire for the first time. In this method, carbon filaments are heated to a high temperature by current in halogen oxide vapor of tungsten containing free hydrogen, so that carbon is completely replaced by tungsten. The incandescent filament made in this way contains carbon more or less, which is not only very brittle, but also the filament of the bulb is constantly dense during use, so the electrical parameters of the filament will change.
In 1904, Jester and Hannaman realized the influence of carbon on brittleness, and used a carbon-free binder to mix with tungsten compounds, then extruded into filaments, and then heated and reduced to metal in hydrogen. The tungsten wire made by this method is very brittle, but because of its much better light efficiency, it can still replace carbon wire, osmium wire and tantalum wire to make light bulbs. [ 1]
relevant information
Cordless lamp
On June 10, 2007, researchers from Massachusetts Institute of Technology conducted the experiment of "cordless light bulb". The research team led by Sol Jasik used two copper wire coils as vibrators, and one coil was connected to a power supply as a transmitter. The other is connected to a desk lamp and acts as a receiver. As a result, they successfully lit a 60-watt electric light at a distance of 2. 13 meters from the transmitter. Moreover, experiments show that wireless power transmission technology is harmless to human beings, because electromagnetic field only affects objects that can vibrate with it.
Structure and luminous principle of LED
Fifty years ago, people knew the basic knowledge that semiconductor materials can emit light. The first commercial diode was produced in 1960. LED is the abbreviation of English light emitting diode. Its basic structure is a piece of electroluminescent semiconductor material, which is put on the shelf with leads and then sealed with epoxy resin to protect the internal core wire, so the led has good seismic performance.
Light emitting diode structure
The core of LED is a wafer composed of P-type semiconductor and N-type semiconductor. There is a transition layer between P-type semiconductor and N-type semiconductor, which is called pn junction. In the PN junction of some semiconductor materials, when the injected minority carriers recombine with the majority carriers, the excess energy will be released in the form of light, thus directly converting electric energy into light energy. When reverse voltage is applied to PN junction, minority carriers are difficult to inject, so they do not emit light. This kind of diode made by injection electroluminescence principle is called light emitting diode, commonly known as led. When working in the forward direction (that is, DC voltage is applied at both ends), when the current flows from the anode of the LED to the cathode, the semiconductor crystal emits different colors of light from ultraviolet to infrared, and the intensity of light is related to the current.
Characteristics of LED light source
1. voltage: LED uses low-voltage power supply, the power supply voltage is between 6-24V, which varies according to different products, so it is safer than using high-voltage power supply, especially suitable for public places.
2. Efficiency: Compared with incandescent lamps with the same light efficiency, the energy consumption is reduced by 80%.
3. Applicability: Very small, each unit LED chip is 3-5mm square, so it can be made into devices with various shapes and is suitable for changing environments.
4. Stability: 654.38+100000 hours, and light attenuation is 50% of the initial value.
5. Response time: The response time of incandescent lamp is millisecond, and that of LED lamp is nanosecond.
6. Environmental pollution: no harmful metal mercury.
7. Color: the color can be changed by changing the current, and the energy band structure and band gap of the material can be easily adjusted by chemical modification of light-emitting diodes, so as to realize multi-color emission of red, yellow, green, blue and orange. For example, an LED that is red at low current can turn orange, yellow and finally green with the increase of current.
8. Price: led is more expensive. Compared with incandescent lamps, the price of several LEDs can be equivalent to the price of an incandescent lamp. Usually, each group of signal lamps needs to be composed of 300 ~ 500 diodes.
led display
Modern display screen adopts LED as backlight display technology.
The first electric lamp in China.
The first electric lamp in China appeared on the eighth day of April in the fifth year of Guangxu reign (1May 28th, 879). At that time, J. D. Bishop, a British electrical engineer working in the Ministry of Industry of Shanghai Concession, was driven by a 10 HP (7.46 kW) steam engine in a warehouse in Zhapu Road, China.
1882, liddell, an Englishman, bought American-made power generation equipment and founded the first power plant in China at the north point of Nanjing Road, Jiangxi Road (now East China Electric Power Administration), and connected 15 lights in series along the Bund. At night, the dazzling arc lamp attracted hundreds of people to watch.
In the 1950s, on Gulangyu Island, as long as the lights were dimmed and turned on, people knew that it was 8 o'clock every night.
new invention
"Gravity lamp" relies on gravity to generate electricity, and its brightness is equivalent to that of a 12 watt fluorescent lamp, so it has a long service life.
Clay Morton from Virginia, USA, received a master's degree from Virginia Tech last year. His research topic is a kind of lamp made of light-emitting diodes, named "Gravia". In fact, it is a cylinder made of acrylic material, and its height is slightly more than 4 feet (about 1.2 1 m). The luminous principle of this lamp is that the heavy objects on the lamp drive the rotor to rotate when it falls slowly, and the electric energy generated by the rotation will electrify the lamp and make it shine.
The luminous flux of this lamp is 600 to 800 lumens (equivalent to the brightness of 12 watt fluorescent lamp) for 4 hours. To turn on the lamp, the operator only needs to move the weight on the lamp from the bottom to the top and put it in the groove at the top. It only takes a few seconds for the weight to slowly descend, and the LED light will be on.
Clay Morton said that operating this light is certainly more troublesome than pressing the switch, but it is still acceptable and more interesting, just like winding a classical clock or leisurely making a delicious cup of coffee. Morton estimated that the service life of Gravia lamps can reach more than 200 years. At present, this lamp named "Gravia" has been applied for and patented.