LCD, Led, Qled, OLED and Future Quantum Dot OLED, Who Is the Perfect Display Screen?
"LCD", "led", "qled", "OLED" and "quantum dot OLED": what is the most perfect display for users? However, at present, quantum dot OLED is still in the experimental stage of research and development, there is no real large-scale production, and it is also in the research and development of large-scale production equipment. According to relevant reports, Samsung display company is expected to start trial production of "quantum dot OLED" (qd-oled) display in the second half of 2019. This is mainly because Samsung, Canon, kateeva and others have jointly developed production equipment, and several major have shortened the equipment development time.For mass consumers: from LCD and led to later qled and OLED, one after another new display technology makes users a little dazzled. They don't know what kind of large screen display device to choose to obtain perfect display effect. Now a "quantum point OLED" has emerged, which makes users more confused.However, for many user groups, they simply don't know what these terms mean. They only focus on which display device has a more perfect display effect among these many display devices. Therefore, the Prudential display technology editor has made the following classification and summary for your reference:
First, introduce the following LCDs. LCD displays usually include the following price parts:First, each LCD splicing unit has an independent backlight system. At the beginning, the LCD backlight used fluorescent tubes and other equipment, while the current LCD LCD splicing unit uses LED backlight. LEDs are simply light-emitting diodes, which can also be understood as "tubes", but their power consumption is low compared with traditional tubes Moreover, it also has obvious advantages in service life, so many types of lamps on the market are led.Second, in addition to a backlight, the LCD splicing unit also needs a light guide plate. Its main function is to evenly distribute the light generated by the backlight into a plane and form a luminous plane.
Third, in addition to the need for the light guide plate to form a plane, it also needs a liquid crystal layer, because the light wall formed by the light guide plate is monochromatic light and cannot form an image. However, the characteristic of liquid crystal is that if the voltage applied to it is different, its motion law will be different, so the light blocked is also different, thus forming the gray level of light and shade, which is often called liquid crystal splicing screen. The more kinds of applied voltage, the greater the gray value, and the more light types it will display.
Fourth, although the liquid crystal can display various types of light through voltage, they are gray screens and cannot display other colors. Therefore, a color filter layer is required. If you observe the liquid crystal splicing unit with a magnifying glass, you will see small red, blue and green dots, that is, the color filter. Usually, the color seen on the LCD splicing large screen is formed through this.Limitation of LCD and OLED and qled:From the principle of liquid crystal display, it can be seen that the light emitted by liquid crystal is actually emitted by the rear lamp tube. So there are two problems
First, there is a limit for liquid crystal molecules to block light. They can't block everything left. The so-called pure black is actually a kind of gray because light can pass through. When the brightness of the screen is turned on, the brightness of the LED backlight will be higher. The more light that has been blocked by the LCD, the more impure the black. Black impure will lead to weak contrast of the screen, and the color of the screen will not be bright after the contrast is limited.Second, the problem of color regionScientifically speaking, the color that can be distinguished by human eyes belongs to the spectral range of visible light, which is quite large, and the display equipment can only display part of it. For the sake of standards, there are RGB, NTSC, NTSC and other standards: about 72% of liquid crystal displays in the early stage, and then gradually to 80% and 90% with the progress of color filter technology. But it is still far from the real world seen by human eyes.
Because both LCD and led have these two problems, the later OLED appeared. In fact, OLED has a long history and can be traced back to Kodak laboratory decades ago, but for mass production, it is in recent years. Compared with LCD, OLED has certain advantages. First, OLED is active light-emitting and does not need any backlight. Second, it can achieve a very small size. Today's mobile phones basically use OLED as the display screen. Another point is that its color can be very realistic and can reach a high color area. This is why the display effect of mobile phone looks better than LCD and led. In addition, the response time of OLED is much faster than that of LCD: it does not need liquid crystal layer and slow movement of liquid crystal molecules. In this way, the effect is much better when displaying dynamic pictures without drag or hysteresis.
But this does not mean that OLEDs are perfect display devices. Take pure OLEDs for example: they should be red, green and blue OLEDs. The three lights are mixed for display, which was done by early Samsung OLEDs. However, TV is different from mobile phones. TV can be seen for hours and every day. The service life of red, green and blue OLEDs is different. With the increase of service time, the TV will be colored after the red attenuation of 50%, green attenuation of 20% and blue attenuation of 30%! So Samsung didn't play like this for a few years.
LG came up with a way to use white OLED. The light source at each point can be turned off and display pure black. However, the color depends on the red, blue and green color filters. Although the color gamut is not as large as the three color LED, there is no problem of service life and color deviation. This is also the main mode of mainstream OLED display devices on the market.
Of course, in addition to OLED, there is a qled (quantum dot). Its principle is similar to OLED. They all emit light actively and can display pure black and high color gamut. However, the disadvantage is that the maturity of qled is worse than OLED. At present, there are no devices that rely on their own light, and the so-called qled display devices on the market use LED backlight, and then the self light of qled mixes the two lights to change the color. This advantage is to use the wide color gamut of qled, but the backlight and liquid crystal layer still exist, and the pure black can not be displayed.
The perfect display screen "quantum dot OLED" is expected to be put into trial production in the second half of 2019. In short, "quantum dot OLED" is the product of technically complementary combination of OLED and qled, and obtains wide color gamut and ultra-long service life while obtaining pure black, ultra-high contrast and fast response time. Theoretically, the produced quantum dot OLED is the perfect display screen, but although the theory is good, how to produce the finished product has become the direction of Samsung and other enterprises, because at present, OLED and qled are two different sets of production equipment. If we want to produce quantum dot OLED first, we also need a new set of production equipment. This is one of the reasons why Samsung cooperates with Canon and kateeva to speed up the R & D of production equipment.
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