OLED has a lot of problems, and the status quo of quantum dots is sluggish. It is said that 2017 is the first year of the official confrontation between OLED and quantum dot displays, and the representative manufacturers of OLED and quantum dots are LG and Samsung respectively, but Samsung also produces OLED panels, and is also the world's largest supplier of small-screen OLED panels, while LG, which mainly produces large-screen OLED display panels, is aimed at the display and TV fields, but recently it was revealed that LG Display's fourth-quarter profit plummeted by 95 percent . OLED is also faulty, and there are often complaints about screen burn-in, and quantum dot display technology is currently in a recession. Both prices are very expensive, and they are not necessarily superior compared to current LCD screens.
Each panel structure
Let's first take a look at the long-standing LCD display technology. The LCD display is a multi-layer complex structure. The structure of the LCD is to place a liquid crystal cell in two parallel glass substrates. A color filter is set on the substrate glass, and the rotation direction of the liquid crystal molecules is controlled by the signal and voltage change on the TFT, so as to control whether the polarized light of each pixel is emitted or not to achieve the display purpose.
According to the light source of the backlight, LCD displays are divided into two types: CCFL (cold cathode fluorescent tube) and LED (light emitting diode). Many manufacturers advertise themselves as LED displays, which leads us to generally believe that LCD and LED are two types of display screens. Wrong, it is completely misleading by the majority of manufacturers, the two are only different from the backlight source.
The OLED panel is very different from the LCD panel. In comparison, the structure of the OLED panel will be simpler. The full name of the OLED is an organic light-emitting diode. That is to say, the light-emitting material of the OLED panel is an organic material. Compared with inorganic materials, organic materials There are inherent shortcomings in lifespan. OLED display technology has the characteristics of self-luminescence. It uses a very thin organic material coating and glass substrate. When there is current passing through, these organic materials will emit light, and the OLED display screen has a large viewing angle and can save power. Because of the characteristics of self-luminescence, OLED is more pure in black, because as long as the material does not emit light, it is black. At the same time, wide viewing angle, high contrast, low power consumption, and high response rate are all characteristics of OLED panels. At present, there are RGB OLEDs and white OLEDs. RGB OLEDs are mainly used in small screens, while white OLEDs are mainly used in large-screen TVs.
In fact, as far as the current quantum dot screen is concerned, compared with the traditional LCD panel, it is only a change in the backlight method, which is an extension of the LCD panel, and there is no fundamental change. In layman's terms, the current quantum dot display is to add a film to the VA panel, which is the QDEF film in the picture above. The current quantum dots are only responsible for generating green and red light, so the white (WLED) LED in the original backlight module must be replaced with a blue LED (Blue LED). At the same time, the application of QDEF film and blue LED light source is also one of the reasons why the color display of quantum dot displays is purer than ordinary displays.
Performance advantages and disadvantages of each panel
Product rate: Due to years of technical iteration and upgrading, the technology maturity of LCD panels is obviously higher than that of OLEDs. Since quantum dots are also rooted on LCD panels, the yield rate is also higher than that of OLEDs. LCD≥Quantum dots>OLED
Color gamut: OLED and quantum dots will be significantly better than LCD panels, which is also a feature that has been emphasized. In terms of parameters, the advantage of OLED in color gamut is not obvious, but this is based on the best OLED and top quantum The judgment made by the comparison of dots, in fact, the OLED panel will be slightly better than the LCD and quantum dots. OLED>Quantum dot>LCD
Light leakage control: OLED fully suspends LCD and quantum dots. Both LCD panels and quantum dot panels are shielded by adjusting the arrangement of liquid crystals, so that the backlight can never be completely shielded, and light leakage is inevitable. OLED>LCD=quantum dots
Color/brightness uniformity: In terms of color/brightness uniformity, due to the backlight mode of LCD panel and quantum dot panel, the best uniformity cannot be achieved, and OLED self-illumination does not require diffused backlight, uniformity more consistent. OLED＞Quantum dot＞LCD
Contrast: Contrast is the difference between the brightest white and the deepest black on the screen, while LCD can have higher brightness support because of the separate backlight module, while OLED has purer black because there is no need to worry about light leakage. In terms of contrast, OLED will be better in contrast. OLED>LCD=quantum dots
Viewing angle: The best IPS panel is comparable to OLED in terms of viewing angle, but the current quantum dot displays generally use VA panels as the basis, and cannot achieve the best viewing angle. OLED≥LCD>Quantum dots
Power consumption control: Because each pixel of the OLED panel needs to be powered separately, the higher the resolution, the more power consumption. In the case of the same brightness, LCD and quantum dots consume less energy than OLEDs, which is why quantum dots often mention that they consume less energy than OLEDs in their promotions, but basically LCDs consume less energy than OLEDs. less. Quantum dots ≥ LCD > OLED
Thickness control: The structure of LCD and quantum dots is relatively complex. In addition to the reason of the backlight module, the thickness is much higher than that of OLED with a simple structure. Therefore, as mobile phones are getting thinner and thinner today, this effect is particularly effective. important. OLED＞Quantum dot＞LCD
Based on the above, it seems that OLED has won an overall victory. The performance of the screen is better than that of quantum dots and LCD. Even the LCD panel with very mature technology has been beaten to the ground, but in fact?
OLED may not perform as well at all
In fact, it is still necessary to return to the more important issue of the panel: cost
At present, because the technology of OLED is not fully mature, the yield rate is low, and the industry chain is not very perfect, and the scale effect has not yet formed, and the cost remains high. Moreover, Samsung's RGB OLED is different from LG's white OLED. The so-called white OLED is to directly use an OLED device that emits white light (in fact, a yellow OLED and a blue OLED device are stacked together) as the pixel point light source, and then pass through Red, green and blue filters filter out colors (similar to LCD panels). RGB OLED is different. Each pixel emits its own light to generate RGB color without filters.
White OLED has low technical difficulty, fast mass production, high profit, and beautiful appearance. This is also the technology adopted by the LG-led OLED camp. The current OLED color TV market is full of TV products with white OLED technology. However, if RGB OLED is used for large-screen production, the technology is complex and difficult to mass-produce, and the yield rate is extremely low. Neither LG nor Samsung has a good solution. This is also the reason why Samsung, Hisense and TCL are reluctant to launch OLED TVs.
There is also a very important natural defect of OLED at present: screen burn-in
But even with LG's white-light OLED, the yield is not good, and the cost has remained high. And it's not just a matter of yield and cost. White OLEDs have insurmountable defects, that is, heavy afterimages, low brightness, high power consumption, short lifespan, and poor image quality with missing pixels.
Many OLED TVs in shopping malls require tellers not to play programs with station logos, not to play still pictures all the time, and to take measures such as taking a break when playing for a long time.
Comparative analysis of LCD/quantum dots/OLED technology: OLED has a lot of problems, quantum dots are half dead
But don't just see a lot of problems with white light OLEDs, even Samsung's current mass-produced RGB OLEDs have the same burn-in and green lines. Since Samsung's own s series and noto series enabled OLED panels, the problem of screen burn-in has not been broken, and the afterimage will accompany the mobile phone for a lifetime.
Apart from the cost factor, for monitors, the problem of afterimage burn-in will be more serious. For example, the resident taskbar at the bottom of the screen, the resident icon on the desktop, etc., is it not that the screen burn is more serious, which is one of the reasons why OLED does not dare to involve the display.
Summarize
LG's LCD panel business has been hit hard this time, with shipments declining throughout the year and profits plummeting. But it doesn't seem to be a good way to immediately turn to OLED, which is still a lot of trouble. With the two core technologies of quantum dots and OLED in hand, Samsung has not been able to shake the current LCD panel. The excessive publicity of OLED and quantum dots over the years has led to higher expectations of consumers, and the results presented to consumers. is a product with numerous defects. For now, or even for some time in the future, it is not realistic for OLED and quantum dots to beat LCD. Don't always advertise how high-tech the new panel is, but first honestly solve the actual problem.
