The order of mobile phones is as follows: (LTPS) TFT > (A-Si) TFT > TFD & gtUFB & gt； CSTN & gt； Stoneboog
Screen material: Screen material, color number, contrast and brightness are the core parameters, which largely determine other parameters. The color screen of mobile phone is different due to the difference of LCD quality and R&D technology, including STN (CSTN), TFT(LTPS), TFD, UFB and organic light emitting diode. Generally speaking, the more colors that can be displayed, the more complex the image that can be displayed, and the richer the level of the picture. At present, there are usually three kinds of color screen mobile phones on the market, namely 256, 4096 and 65536(65K), and some high-end models have reached 262144 (260,000). The higher the series, the better the display effect. Personally, I think the mobile phone with camera is better than 65K, and the contrast and brightness should be adjustable.
STN screen: STN (Super Twisted Nematic) is the LCD that we contact most. Compared with other liquid crystal displays, STN is a passive matrix liquid crystal display. Its advantage is low power consumption, the biggest advantage is power saving, and the price is relatively cheap. Disadvantages are poor brightness, poor color number and poor contrast. Under strong light, the screen may not be clear, the reaction speed is slow, and it is easy to play dynamic images.
The display principle of color STN is to add a color filter to the traditional monochrome STN liquid crystal display, divide each pixel in the monochrome display matrix into three sub-pixels, and display the three primary colors of red, green and blue through the color filter, thus displaying a color picture. Unlike TFT, STN is a passive LCD screen, which can display up to 65K colors. Not counting the gray STN, there are mainly CSTN and DSTN in STN now. CSTN, or color STN, generally adopts transmission lighting. The transmission screen should be illuminated by an external light source, which is called backlight, and the light source should be installed behind the LCD. Transmission LCD displays well in normal light and dark light, but it is difficult to see the display content clearly outdoors, especially in the sun, and the backlight consumes a lot of power. DSTN, or double-layer STN, used to be mainly used in some notebook computers. It is also a passive display technology, using two display layers. This display technology solves the drift problem in traditional STN display, and because DSTN also adopts double scanning technology, the display effect is greatly improved compared with STN.
Representative models: STN screen is preferred for low-end models, and the price is generally not higher than 2000 yuan, such as Nokia 66 10i, Siemens C62, etc.
UFB screen: UFB is ultra-fine &; Short for & Guangming. In March 2002, Samsung Electronics, which occupies the first place in the global LCD market, released a UFB LCD for mobile phones, which is characterized by ultra-thin and high brightness. In design, UFB LCD also adopts a special grating design, which can reduce the pixel spacing and obtain better image quality. Generally, UFB LCD can display 65536 colors with a resolution of 128× 160 pixels. At the same time, the contrast of UFB LCD is twice that of STN LCD. 65536 colors, the brightness is comparable to TFT display, but the power consumption is less than TFT display, and the price is similar to STN display. At present, UFB displays are mainly mid-to high-end models of Samsung and LG, and their usage is not very good.
Representative models: Samsung X608(65K color), LG 8 10(65K color), etc.
TFD screen: TFD is short for thin film diode. TFD technology was developed by Seiko Epson, a mobile phone screen giant, and used on mobile phone screens. Because TFT consumes power and costs a lot, it undoubtedly increases the usability and cost of mobile phones. It is a compromise between TFT and STN. It has better brightness and color saturation than STN, but it saves more power than TFT. The key features of TFD are "high image quality, ultra-low power consumption, miniaturization, dynamic image display ability and fast response time". The display principle of TFD is to equip each pixel on the LCD with a separate diode as the control source. Because of this separate control design, each pixel will not affect each other, so dynamic pictures and bright colors can be displayed on the TFD screen without afterimage. Like TFT, TFD is also driven by active matrix. Initially developed TFD can only display 4096 colors, but if image processing technology is adopted, it can display images equivalent to 260,000 colors. However, compared with TFT, it is still inferior in color display, and now it is mainly used by Japanese and Korean manufacturers.
Representative models: Samsung V208(65K color), Sony Ericsson Z608(65K color), LG 8280 (26 260,000 color), Lenovo G900 (26 260,000 color), etc.
TFT screen: TFT (thin film transistor) is a kind of active matrix liquid crystal display (AM-LCD). TFT is equipped with a special lamp on the back of the liquid crystal, which can "actively" control each independent pixel on the screen. This is the origin of the so-called TFT (Active Matrix TFT), which can greatly improve the reaction time. Generally, the reaction time ratio of TFT is faster, and it will flicker if it is about 200 ms.. Moreover, because TFT is an active matrix LCD, the arrangement of liquid crystals can be remembered, and it will not recover immediately after the current disappears. TFT also improves the phenomenon that STN will flicker (ripple) and blur, and effectively improves the playing ability of dynamic pictures. Compared with STN, TFT has excellent color saturation, reduction ability and higher contrast, but its disadvantages are higher power consumption and higher cost.
Representative models: mid-to-high-end models are preferred, and the price is generally more than 2,500 yuan, such as Nokia 7200(65K color), Sony Ericsson K700C(65K color), Amoi DF9 (26 260,000 color), NEC N600 (26 260,000 color) and so on.
Organic light-emitting diode screen: Organic light-emitting display (OLED) is a new type of mobile phone liquid crystal display, which is called "dream display". Organic light emitting diode display technology is different from the traditional liquid crystal display mode. It does not need backlight, and uses non-very thin organic material coating and glass substrate. These organic materials will emit light when current passes through them. In addition, the organic light-emitting diode display screen can be made lighter and thinner, with a larger viewing angle, and can significantly save electricity. At present, in the two major organic light-emitting diode technology systems, the low-molecular-weight organic light-emitting diode technology is controlled by Japan, while the polymer PLED technology and patents are controlled by the British technology company CDT. Compared with PLED products, it is still difficult to color, while low-molecular organic light-emitting diodes are easier to color. However, although the OLED with better technology will replace LCD such as TFT in the future, the OLED display technology still has some shortcomings, such as short life and difficult to enlarge the screen. At present, organic light-emitting diodes are mainly used on the outer screen of dual-screen mobile phones, mostly in 256 colors. Because the external screen is not the focus of our attention, we will not mention the representative models here.
LTPS screen: TFT has the best display effect, which can be divided into several categories. At present, most TFT panel products on the market adopt a-Si TFT manufacturing process, and a few small-sized products begin to adopt low-temperature polysilicon process. Low-temperature polysilicon TFT is a new generation of products derived from TFT, which has the characteristics of ultra-thin, light weight and strong durability, plus the advantages of fast reaction speed, low power consumption and glass-mountable circuit. The application covers mobile phones, PDA, etc. The biggest difference between LTPS TFT and a-Si TFT is that it can provide brighter and finer pictures, which is lighter and more energy-saving. However, not all manufacturers are willing to use it because it has not yet formed mass production and the cost is high. According to the international photoelectric and display forecast, by 20 10, 80% of the global mobile phone panels will be replaced by TFT-LCD, among which LTPS with the best display effect is one of the main forces.
Representative models: high-end model patents, Alcatel OT835 (26 260,000 colors), Konka A08 (26 260,000 colors), etc.
Other types: We can also see some other LCDs on some mobile phones, such as Sharp's GF screen and CG (Continuous Crystal Silicon) LCD. Finally, there are two principles in choosing a color screen mobile phone: First, it is good to have enough, and there is no need to waste it. Second, the configuration should be reasonable, and the functions such as display screen, camera, chord ringtone and standby time should be coordinated.
Comparison of UFB, STN and TFT
STN is the main equipment of early color screen, which can only display 256 colors at first. Although it can display 4096 colors or even 65536 colors after technical transformation, the general STN is still 256 colors, which is cheap and low in energy consumption.
TFT has good brightness, high contrast, strong layering and bright colors. Disadvantages are high power consumption and high cost.
UFB is a display screen specially designed for mobile phones and PDA, which is characterized by ultra-thin and high brightness. It can display 65536 colors with a resolution of 128× 160. UFB display adopts special grating design to reduce pixel spacing and obtain better picture quality. UFB combines the advantages of STN and TFT: the power consumption is smaller than TFT, and the price is similar to STN.
Screen size: The screen size of a mobile phone is divided into two concepts: physical size and display resolution.
Physical size refers to the actual size of the screen. The large screen must be equipped with high resolution at the same time, that is, how many pixels can be displayed in this size, and the more pixels are displayed, the greater the room for performance. The screen sizes of the two mobile phones are almost the same, but one can only display two lines of Chinese characters and the other can display five lines of Chinese characters. Aside from the difference in font size, the key is the resolution of the screen. The resolution is a little larger, and more lines of Chinese characters can naturally be displayed under the same font size. Color screen mobile phone is really good. Without enough resolution, what's the use of high color quality? Color mobile phone screen is generally around 128× 128.
Screen resolution is the screen resolution obtained by dividing the number of liquid crystal cells ([dots]) by the screen area, which is the biggest factor determining the picture quality. Therefore, when purchasing a color screen mobile phone, we should not only pay attention to the depth of color that can be displayed on the screen, but also the screen resolution is a very important determinant.
The dot matrix screen is 128* 128 (or (128+-x)*( 128+-x), and x is between 1 and 32), and the aspect ratio is/kloc-0.