For a long time, the reason why people do not use LEDs for lighting is mainly because LEDs usually emit only red or yellow light. To obtain white light, LEDs that emit blue light have to be manufactured. In this way, red, yellow, blue three kinds of light "mixed", it produces white light. This troublesome problem has finally been solved. Scientists have discovered a new type of semiconductor material, gallium nitride, which emits blue light when properly processed. Blu-ray problem is solved, the issue of the white light there is hope. Colin Hanfiles, a faculty member at the University of Cambridge in the United Kingdom, said that they have experimentally developed light-emitting diode light bulbs that emit light very close to the sun and have good prospects. He said LED bulbs are made of semiconductors, so the light-emitting devices can be made as small as a few millimeters and mount them on walls or ceilings, barely detect their presence without turning on the lights, It eliminates the need to wear an ordinary incandescent lamp shade to prevent eye-catching light trouble. In addition, the life of this light bulb is very long, almost no need to replace it, and in the future people may forget about changing the light bulb. He is calling on the British government to increase its investment so as to ensure that Britain can take the lead in this field of technology. In addition to durability, this light bulb also has great potential for energy savings. It has been calculated that if half of the bulbs in the United States use LED bulbs, 24 power stations can be shut down, saving billions of dollars and carbon dioxide emissions will drop significantly. That is why the United States has planned to use LED bulbs for all traffic lights by 2006, saving $ 750 a year at each intersection. Despite the many advantages of such light bulbs, there are two major hurdles to truly entering the average household. First, the price is too high, the price of each bulb is 30 pounds, while only 35 pence ordinary incandescent bulbs, the gap is too large. Second, it is also difficult to produce a white light bulb suitable for home use. However, developers believe the price of such light bulbs could drop to £ 5 each over the next five years. By then, LED bulbs will stand out from the traditional LED lights to become a star in the field of lighting.