Dazzling invention - the story of Iman and others' invention of the fluorescent lamp. In 1879, the famous American scientist Edison invented the incandescent lamp, ending the "dark" history of mankind. While people are cheering and celebrating this great invention, far-sighted scientists have seen the obvious shortcomings of incandescent lamps: it only uses 10%-20% of electrical energy, and the remaining 80%-90% of the electrical energy is lost as heat. form is wasted. "Incandescent lamps rely on current heating to convert heat energy into light energy. This form of utilization of electrical energy is too wasteful. Can we open up a new way to utilize electrical energy?" Some scientists have put forward new ideas. Hewitt from the United States is one of the scientists who holds this idea. He plunged into the experiment silently. He made a lamp out of heat-resistant glass and sucked out the air inside the tube. Then fill the lamp with various metals and gases and compare them repeatedly. In 1902, Hewitt invented the mercury lamp. This kind of mercury lamp is a vacuum lamp filled with mercury and a small amount of argon. When electricity is applied, the mercury evaporates and is excited by electrons to emit light. Mercury lamps are much brighter than incandescent lamps, the light is similar to sunlight, and the energy utilization rate is also higher. However, mercury lamps radiate a large amount of ultraviolet rays, which are harmful to the human body; and the light of mercury lamps is too bright and dazzling, so it cannot be widely used. For a time, many scientists concentrated on the research of mercury lamps. They decided that if they continued to study along the lines of mercury lamps, they would eventually succeed. Many scientists have noticed that as early as 1852, the British physicist Stoker discovered a fluorescent substance that can produce another kind of light when it encounters light, and the wavelength of the light converted by this fluorescent substance is much longer. It is longer than the wavelength of external light. "Since ultraviolet light has a shorter wavelength than visible light, if you use ultraviolet light to illuminate fluorescent substances, you can definitely get visible light with a wavelength much longer than ultraviolet light!" The scientist immediately thought of the disadvantages of mercury lamps. "There is no way out despite the mountains and rivers, but there is another village with dark willows and bright flowers." This is a very valuable speculation. It means that a large amount of harmful UV rays will become visible light. Specifically, as long as the inner wall of the mercury lamp is coated with a fluorescent substance, when the ultraviolet radiation radiated by the mercury lamp hits the fluorescent substance, it will be excited and become visible light. With such a clear theoretical guidance, it stands to reason that the improvement of mercury lamps should make a leap forward. After careful analysis and discussion, the scientists determined that the original speculation was correct. The key problem was that the technology did not pass the test. In other words, the starting device of the mercury lamp was not ideal. But making an ideal starting device is not easy! The improvement of mercury lamps has entered a difficult stage. In 1910, French scientists noticed an experiment done by More in 1895. In this experiment, Moore filled a small amount of carbon dioxide into a glass lamp that had been evacuated from the air, and then applied high voltage to discharge it. As a result, the lamp emits white light. Based on Mohr's experiment, Kraut filled the glass lamp tube with the air removed and filled it with inert gases such as neon, argon, and helium. He found that when neon was filled, the lamp would emit reddish-orange light; when a mixture of neon and argon was filled, the lamp would emit blue light; when a mixture of neon and mercury was filled, the lamp would emit green light. Light; filled with helium, the lamp will emit golden light. If different fluorescent substances are coated on the inner wall of the tube, the color of the light will be richer. "What a wonderful phenomenon this is!" Kraut was pleasantly surprised. Kraut made a promotional advertisement based on the special properties of this light: red flowers, green leaves, and yellow text. He hung this advertisement in the downtown area of ??Paris, France. At night, this advertisement glows with colorful lights, making it particularly eye-catching. Kraut obtained a patent for the invention of neon lights and established the "Krauter Neon Light Company", which resulted in a fortune. It was not until 1932, when Kraut's patent expired, that neon lights began to be widely produced around the world. Although the neon light is not bright enough to be used as lighting and can only be used for advertising with its rich light colors, it once again proves that instead of using Edison's method of turning electricity into heat and heat into light, a more economical method is adopted. It is completely feasible to use electricity efficiently. In other words, further development and improvement of mercury lamps are promising. This gives scientists great confidence. Iman, a researcher at General Electronics in the United States, like other scientists, sees a bright future in the bright light of neon lights. He accelerated the pace of development. Finally, in 1938, he broke through the design and production of starting devices and produced fluorescent lamps with completely different performance from mercury lamps.
This kind of fluorescent lamp is a glass tube filled with a certain amount of mercury. The inner wall of the tube is coated with fluorescent powder, and there is a filament at each end of the tube as an electrode. Its working principle is: after electricity is applied, the mercury vapor is discharged and ultraviolet rays are generated at the same time. The ultraviolet rays excite the fluorescent material on the inner wall of the tube and emit visible light. Obviously, fluorescent lamps do not have the disadvantages of mercury lamps. They are brighter than incandescent lamps, have high power utilization and save electricity. Therefore, as soon as it was born, it quickly entered the general family. Since the composition of fluorescence is similar to that of sunlight, people also call it "fluorescent lamp".