How does quantum dot display technology improve the image quality of tiny crystals?

Although advanced display technology has been outstanding, its display effect still has room for further improvement. Even the best LCD screen can only produce one-third of the color perception range of human eyes (with the cooperation of human brains). However, with the application of quantum dot matrix technology in display screen, this situation will be improved soon. Quantum dot is a kind of semiconductor crystal, and its size is about a few nanometers (one billionth of a meter), which is equivalent to more than 50 atoms wide. This crystal glows when it is excited. The wavelength and color of light depend on the size of the crystal. Larger crystals emit long-wave light (red light), while smaller crystals emit short-wave light (blue light). The light emitted by crystals with a size between the two forms a chromatographic band, such as green. The plan uses this feature to produce subtle differences in colors, which is beyond the display range of existing LCD screens. LCD is made of a strange liquid crystal substance. This kind of liquid crystal contains countless fine gratings, which can allow or prohibit white light to pass through. When the fine grating works, the optical polarity of the liquid crystal can be controlled by the circuit. In most liquid crystal displays, light is generated by light emitting diodes, and then they are scattered to a special screen layer behind the grating. White light enters the filter after passing through the liquid crystal grating, and only one of the three main colors of red, green and blue can be output after filtering. By combining every third filter with a grating (including a main color), an independent image unit or pixel is produced. By changing the luminous flux of the grating and combining the three main colors in different proportions, the color range generated by each pixel can be determined. On the rainbow a few years ago, it would be amazing if the number of colors on the display screen could reach one-third of the range of human color perception. But times are progressing, and Jason Hartlove, the boss of California Nanosystems, thinks he has a better way to improve display technology. He said that California Nanosystems has adopted a technology called quantum dots, which can further increase the number of colors that can be displayed. The problem to be solved by quantum dots is that the light of LCD, which is the first choice in the display industry, is not bright enough. The light they emit is biased towards the blue end of the spectrum. This color difference is reflected in various frequencies that make up the screen image. Some viewers will think that this color looks cold. California Nanosystems has a product called Quantum Dot Enhanced Film. They use quantum dots to modify the spectrum of LED, so that its white light can be closer to the adaptation range of human eyes. As the product name shows, quantum dot technology really improves the display effect. Its principle is to let the light of LED pass through a transparent film covered with quantum dots, which can absorb the light and re-emit part of it. These quantum dots have two specifications. The larger one will re-emit absorbed energy in the form of red light. The smaller ones will glow green again. According to California Nanosystems, the final filtered image is generated by a color palette with a wider color range, which is 50% wider than the existing LCD. California Nanosystems claims that another advantage of this technology is that it is easy to produce according to the existing production process. Only the scattering layer of LED is replaced by quantum dot enhancement film. The film itself is also easy to make. Quantum dots are made of indium phosphide semiconductor. They are sprayed on a transparent plastic sheet, then covered with another plastic sheet, and finally they are heated and packaged. Film can be produced continuously in rolls, which is somewhat similar to the printing process. This greatly reduces the cost. Hartlove said that this result may make color movie-level effects appear on small display screens. It can also be extended to new application fields, such as professional quality color photography, notebook computers, mobile phones and other equipment. Using this method to improve the traditional LCD may only be the beginning of the application of quantum dot technology. Some engineers think that this technology can be used to improve the technology of the whole generation of display screens. Now, many people in the industry believe that the next generation display screen will be made of organic light emitting diodes (OLEDs). The difference between organic diode and standard diode is that the light of standard diode must be filtered and processed to get the correct intensity and color. Organic diodes have diodes with different structures for each primary color that can be provided, so that pixels can be directly generated. Organic light emitting diodes are brighter, richer in color and deeper than LEDs. This kind of monitor itself is thinner and consumes less power-all functions are attractive. Unfortunately, large-size organic light-emitting diode displays are expensive to manufacture, and their life span is not as long as that of standard LEDs. A more novel idea, quantum dots, may fill the gap of other technical defects. In fact, they promised even higher brightness than organic light-emitting diodes. Organic light-emitting diodes, which may completely replace organic light-emitting diodes. In addition to high brightness, the value of organic light-emitting diodes lies in that the electric energy supplied and controlled by organic light-emitting diodes can be directly converted into the light seen by the audience. This light does not need to be filtered and treated. Quantum dots may also have the same structure, so they can also generate light directly from electricity. Now the circuit for controlling the display screen of organic light-emitting diodes has been developed, and it should be simple to replace organic light-emitting diodes with quantum dots. At the beginning of this year, researchers from Samsung Electronics did this experiment. They showed an experimental quantum dot display screen made of red, green and blue quantum dots, which was powered and controlled by a special transistor array. But Samsung is not the only one doing this experiment. Recently, QD Vision Company in Massachusetts used quantum dots to whiten the output of LED lighting equipment. They showed the prototype of quantum dot display screen, claiming that its efficiency and color level can be comparable to that of organic light-emitting diode display screen. Although QD Vision said that there is still a lot of work to be done before the commercialization of this display technology, the company believes that quantum dot displays will eventually be cheaper than organic light-emitting diodes. Quantum dot technology may not only be applied to display screens. Engineers of British company Nanoco believe that quantum dot technology can help to generate solar energy. The company plans to improve the efficiency of solar cells by adjusting the incident effect of sunlight so that solar cells can fully absorb more energy. For these solar cells, to replace the existing large-scale power generation methods, such as coal and natural gas, the most important thing is efficiency.