stn vs tft display brands
FSTN LCD monochrome displays contain a retardation film applied to the STN display to produce a black and white display. This produces a higher contrast and wider viewing angle then STN or TN.
STN LCD monochrome displays require less power and are less expensive to manufacture than TFT’s. They produce a sharper contrast then TN but less sharp then FSTN. Basic color options are Gray, Blue and Yellow/Green (most common). Other colors are available through the use of filters.
TN LCD monochrome displays are the lowest cost of the three options. Contrast is not as sharp as STN and FSTN. Primary color options are black letters on a grey background. Other colors are available through the use of filters.
Character LCD module (aka alphanumeric LCD display)The majority of character LCD modules listed below are STN 8 x 1 LCD Display, 8 x 2 LCD Display, 16 x 1 LCD Display, 16 x 2 LCD Display, 16 x 4 LCD Display, 20 x 2 LCD Display, 20 x 4 LCD Display, 24 x 2 LCD Display, 40 x 1 LCD Display, 40 x 2 LCD Display, 40 x 4 LCD Display.
Segment Display (aka static LCD displays, seven segment display, glass only LCD display)The majority of segment displays listed below are TN, but can be ordered in STN 7(seven) segment LCD display, 14(fourteen) segment LCD display, 16(sixteen) segment LCD displays, multiplex, mux, common mode LCD.
Graphic Displays (aka dot matrix LCD module)The majority of Graphic Displays listed below are FSTN, but can be order in STN 122 x 32 graphic LCD display, 128 x 128 graphic LCD display, 128 x 64 graphic LCD display, 240 x 64 graphic LCD display
First, what is the LCD junior physics to learn the material has three states: solid, liquid and gaseous. The following LCD screen manufacturers tell about the difference between STN LCD and TFT LCD. In fact, the so-called three-state is only a general distinction, some of the solid matter can be subdivided into different states of the state. Similarly, the liquid can also have a different "state", where the molecular arrangement of the direction of the liquid we call it "liquid crystal", referred to as "liquid crystal". Ordinary solid crystals have directionality, so many of their physical properties also have directionality. Liquid crystals have a general crystal in the direction of the same time with the liquid flow. If you want to change the direction of the solid crystal must rotate the entire crystal, and the liquid crystal is different, and its direction can be controlled by the electric field or magnetic field. Both STN and TFT use a so-called "nematic" liquid crystal (Nematic), it is filamentous, the use of electric field to control the "filament" liquid crystal direction is the application of commonly used method. Liquid crystals are usually made of liquid crystal in two pieces of glass. The surface of the glass is coated with a layer of substances called the agent, by its type and treatment methods can be controlled in the absence of external electric field when the liquid crystal arrangement. Second, STN LCD principle The world"s first liquid crystal display appeared in the early seventies, known as the TN-type liquid crystal display (Twisted Nematic, twisted nematic). In the 1980s, the STN type liquid crystal display (Super Twisted Nematic) appeared, while the TFT liquid crystal display (Thin Film Transistor) technology was proposed. We first talk about the principle of TN-type LCD, STN LCD and TN LCD display the same principle, but the distortion of the liquid crystal molecules are different. The nematic liquid crystal is sandwiched between two pieces of glass, and the surface of the glass is first plated with a transparent and electrically conductive film for the electrode, and then plated with a surface alignment agent on the glass with the film electrode so that the liquid crystal A specific and parallel to the direction of the glass surface. The natural state of the liquid crystal has a twist of 90 degrees, the use of electric field can make liquid crystal rotation, the refraction coefficient of liquid crystal with the direction of the liquid crystal changes, the result is light after TN type LCD polarized polarity changes. As long as the appropriate thickness is chosen so that the polarity of the light changes just 90 °, two parallel polarizers can be used so that the light can not pass at all. And a large enough voltage can make the liquid crystal direction parallel to the direction of the electric field, so that the polarity of the light will not change, the light can pass through the second polarizer. So, you can control the light of the light and dark. As mentioned earlier, STN-type liquid crystal and TN-type liquid crystal display the same principle, but it will be incident light rotation 180 ~ 270 degrees, rather than 90 degrees. Moreover, the simple TN-type liquid crystal display itself only two changes in light and shade. While the STN LCD is light green and orange-based. However, if the traditional monochrome STN LCD display with a color filter, and the monochrome display matrix for each pixel is divided into three sub-pixels, respectively, through the color filter display red, green and blue primary colors, you can display Out of color.
Due to the principle of TN and STN type liquid crystal display, if the display part of it is bigger and bigger, then the central part of the electrode reaction time may be longer. In fact, this is not a big problem for the phone, because the current mobile phone display are relatively small, the impact of liquid crystal reaction time is relatively small. But for notebooks and other equipment need large-screen LCD display, too slow LCD reaction time will seriously affect the display, so TFT LCD technology has aroused the attention of manufacturers. In addition, the color screen in the application of more and more mobile phones in a new generation of products are supported 65536 color display, and some even support 16 million color display, when the TFT"s high contrast, rich color advantage even more important The
LCD screen manufacturers STN LCD is a reflective LCD device, its advantage is small power consumption, but in a dark environment, poor resolution, so have to be equipped with external lighting. The TFT LCD with "back through" and "reflection" in combination, in the back of the LCD set a special light pipe. This is why we see some mobile phone next to the screen seems to have "lights", and some of the phone"s light is like the screen itself issued a reason. Moreover, the LCD screen manufacturers of liquid crystal display backlight technology is also constantly progress, from monochrome to color, from thick to thin, from the side of the fluorescent lamp to flat fluorescent lamp.
By the way, the reflective LCD device has black and white characters (NB) and black and white (NN) two, recently we see the V70 display is belonging to the NB type, of course, this is certainly the integration of the latest technology Enhanced NB. Well, we still get down to business, continue to TFT LCD display principle. TFT liquid crystal display technology using the "active matrix" approach to drive. Method is the use of thin film technology made of the transistor electrode, the use of scanning method "initiative" to control any one of the display points on and off. Light source when exposed through the lower polarizing plate up through the liquid crystal molecules through the light. When the electrodes are turned on, the liquid crystal molecules change like the TN liquid crystal arrangement, and also through the shading and light transmission to achieve the purpose of the display. Sounds like this and TN-type LCD display principle is almost, indeed so. But the difference is that since the FET transistor has a capacitive effect, it is possible to maintain the potential state, and the liquid crystal molecules that have been transmitted will remain in this state until the FET electrode is energized again to change its arrangement. And TN-type liquid crystal does not have this feature, liquid crystal molecules once the electric field, immediately return to the original state, which is TFT LCD and TN liquid crystal display the principle of the biggest difference.
TFT LCD for each pixel are equipped with a semiconductor switch, the processing technology is similar to large-scale integrated circuits. Because each pixel can be directly controlled by the point pulse, therefore, each node is relatively independent, and can be continuous control, this design not only improves the reaction speed of the display, and can accurately control the display gray, so TFT LCD The color is more realistic.
1.TN-type liquid crystal display due to low technical level, low price, application range of small-size products under 3 inches and can only show black and white monochrome and do some simple text, digital display, mainly used in electronic watches, calculators, simple handheld game consoles and other consumer electronics.
2.STN-type liquid crystal display is simpler than TFT-type process, high yield, relatively cheap, for the contrast between strong and screen conversion reaction time faster commodities, so more applied to information processing equipment. If you add a color filter in front of the LCD panel, you can display a variety of colors, even up to the degree of full color. These products are mostly used in the display of text, digital and graphics functions, such as low-grade laptops, handheld computers, stock machines and personal digital assistants (PDAs) and other portable products.
3. TFT LCD display because the display reaction speed is faster, suitable for animation and video display, so it is widely used in digital cameras, LCD projectors, laptops, desktop LCD monitors. Because it is better than STN-type products in terms of color quality and reaction speed, it is also the mainstream product on the market.
The LCD follows a series of rules that are different from CRT displays. THE LCD overcomes the shortcomings of CRT"s large size, power consumption and flickering, but also brings problems such as high cost, low viewing angle and unsatisfactory color display. CrT displays can be selected in a range of resolutions and can be adjusted to screen requirements, but LCD screens contain only a fixed number of LCD units and can only be displayed at one resolution (one pixel per unit) on the full screen. The CRT usually has three electronic guns, and the electron stream that is fired must be precisely aggregated or it will not be clearly displayed. However, there is no focus problem with the LCD because each LCD unit is switched on and off separately. That"s why the same picture is so clear on the LCD screen. LCD also does not have to worry about refresh frequency and flickering, the LCD unit is either on or off, so the image displayed at a low refresh frequency of 40-60Hz will not flash more than the image displayed at 75Hz. On the other hand, lcd units of LCD screens are prone to defects. For the 1024x768 screen, each pixel consists of three units, responsible for the red, green, and blue display of one unit so a total of about 2.4 million units (1024x768x3 x 2359296). It is difficult to guarantee that all these units are intact. Most likely, some of them have been shorted (with "bright spots") or broken (with "black spots"). Lcd displays contain things that are not used in CRT technology. The light source for the screen is the fluorescent tube that wraps behind it. Sometimes we find unusually bright lines in one part of the screen. There may also be some indecent stripes, a special light color
IPS (In-Plane Switching) lcd is still a type of TFT LCD, IPS TFT is also called SFT LCD (supper fine tft ),different to regular tft in TN (Twisted Nematic) mode, theIPS LCD liquid crystal elements inside the tft lcd cell, they are arrayed in plane inside the lcd cell when power off, so the light can not transmit it via theIPS lcdwhen power off, When power on, the liquid crystal elements inside the IPS tft would switch in a small angle, then the light would go through the IPS lcd display, then the display on since light go through the IPS display, the switching angle is related to the input power, the switch angle is related to the input power value of IPS LCD, the more switch angle, the more light would transmit the IPS LCD, we call it negative display mode.
The regular tft lcd, it is a-si TN (Twisted Nematic) tft lcd, its liquid crystal elements are arrayed in vertical type, the light could transmit the regularTFT LCDwhen power off. When power on, the liquid crystal twist in some angle, then it block the light transmit the tft lcd, then make the display elements display on by this way, the liquid crystal twist angle is also related to the input power, the more twist angle, the more light would be blocked by the tft lcd, it is tft lcd working mode.
A TFT lcd display is vivid and colorful than a common monochrome lcd display. TFT refreshes more quickly response than a monochrome LCD display and shows motion more smoothly. TFT displays use more electricity in driving than monochrome LCD screens, so they not only cost more in the first place, but they are also more expensive to drive tft lcd screen.The two most common types of TFT LCDs are IPS and TN displays.
From their discovery in 1888 to their first application within displays in the 1960s, liquid crystals have become a mainstream material choice with many impactful applications in the world of electronics.
As the key component behind liquid crystal displays (LCD), these materials change light polarization to create vibrant, high-resolution images on digital screens. The growth of LCD technology has helped propel the larger display panel market enormously, with industry valuation projected to reach $178.20 billion by 2026.
A prolific variety of LCD types has been developed to best meet their exact use-cases and end-environments. Displays may be optimized for power consumption, contrast ratio, color reproduction, optimal viewing angle, temperature range, cost, and more.
Passive Matrix LCDs offer a cost advantage (both parts and tooling) and are highly customizable. The counterpart to Passive Matrix displays are Active Matrix displays.
Furthermore, the processes used for manufacturing Active-Matrix LCDs can create much finer details on the electrode structure. This allows splitting each pixel in three sub-pixels with different color. This together with the better voltage control allows full color displays.
The transistor switches used in Active Matrix Displays must not protrude significantly above the surface of the display substrates lest they might interfere with a uniform liquid crystal layer thickness. They must be implemented in thin films of suitable materials. Hence, the name Thin Film Transistors (TFT). While AM and TFT have a different meaning, they are often used interchangeably to indicate a higher performance display.
TFTs can be formed by amorphous silicon (denoted α-Si TFT), by poly-crystalline silicon (LTPS for Low Temperature Poly Silicon), or by semiconducting metal oxides (Ox-TFT or IGZO-TFT for Indium Gallium Zinc Oxide).
Currently the most common Electronics Display Technology on the market is LCD technology and among LCD technologies, TFT display technology is the most widely used across consumer applications (laptops, tablets, TVs, Mobile phones, etc.) as well as many industrial, automotive, and medical applications.
As the first commercially successful LCD technology, Passive Matrix Twisted Nematic (TN) LCDs use a 90° twist of the nematic LC fluid between two polarizers to display information. The twist of the LC fluid either blocks light from passing through the LCD cell or allows light to pass, depending on the applied voltage. The applied voltage changes the twisted nematic orientation into an orientation that does not change the polarization of tight. This is called the TN effect.
TN displays can be normally white (NW) when they use two orthogonal liner polarizers or normally black (NB) when parallel linear polarizers are used. ‘Normally’ refers to what happens when no voltage is applied.
Initially, Passive TN LCDs were used in segmented, icon, or character displays where an image element was turned “on” and “off” depending on how the fluid was driven. Improvements were made along the way to address the limited viewing angle of TN technology, which can suffer from contrast loss or even inversion at shallow angles.
It can be advantageous to twist the director of the nematic phase a bit more than 90 degrees, but less than 180 degrees. Displays like this are a subset of TN displays and are sometimes caller Hyper Twisted Nematic Displays.
The numbers of rows or icons that can be addressed in a TN display without Active Matrix addressing is very limited. This is related to how strongly the liquid crystal responds to the applied voltage. Twisting the LC nematic fluid more than 180 degrees (typically between 210 and 270 degrees) causes the display to require a much smaller voltage difference between on and off pixels. This in turn allows addressing of many more rows without an active matrix. Displays with a twist between 210 and 270 degrees are called Super Twisted Nematic displays.
The higher display resolution of STN displays comes at a price. The optical effect is no longer neutrally black and white as in a TN display. Rather these displays are naturally yellow and black or blue and white. The color can be somewhat compensated with colored polarizers, but that comes at the expense of brightness and contrast.
The color in STN displays is caused by birefringence. Adding the same birefringence in the opposite direction can compensate for the effect. Initially this was done by stacking two STN displays on top of each other. This is referred to as Double STN or DSTN, but this is of course thicker and more expensive.
The birefringence of an STN display can be approximated with a stretched transparent plastic film. Adding such a film to an STN display instead of the 2nd STN display is a lot more attractive and has almost the same performance. This is referred to as a Film Compensated STN display (FSTN, or sometimes if two films are used as FFSTN).
FSTN displays are used commonly in consumer, medical and industrial display applications that require low cost and do not need high resolution images or full color.
Another development to the TN display was to use the same concept as in FSTN displays on TN displays. However, the film cannot just be a stretched polymer. Instead, a twisted liquid crystal structure is made and polymerized into a film that is used as a compensation film for TN displays. As this method mostly improves the display characteristics at shallow viewing angles while preserving the excellent performance in straight on viewing, this technology is called Wide View Twisted Nematic (WVTN).
The above display technologies have liquid crystal molecules that are aligned nearly parallel to the display surface with more or less twisting when going from one substrate to the other. In VA (also called VAN) displays, the liquid crystal molecules are aligned vertically with respect to the display surface. Applying a voltage causes the molecules to lay flat, with or without twist.
The advantage of this arrangement is a very dark black state with very little light leakage. This allows making displays with a black mask and colored icons or symbols. These displays look like color displays with brilliant colors, however each image element or icon can only have its assigned color or black.
Due to the ability in AM displays to address one row while the other rows are isolated, the demands on the electro-optical performance of the Liquid Crystal Configuration are less stringent. In principle, all the above mentioned configurations can be used in AM displays. In practice, TN, and WVTN are frequently used as well as some versions of VA technology described below. (MVA, AIFF-MVA, PVA, ASV).
The advantage of these technologies is a much wider and more symmetrical viewing angle along with the elimination of the contrast inversion (or color shift) seen in TN TFT LCDs when viewed from various angles. IPS and FFS displays also are less sensitive to pressure, which is a big advantage in touchscreen displays.
Here, each color sub-pixel is further divided into zones (called domains) having a different direction of the molecular movement when voltage is applied. Again, the purpose is a much wider and more symmetric viewing performance and the elimination of color shifts and contrast inversion at shallow angles. MVA technology achieves that with carefully designed protrusions on the inside surfaces of the display, while PVA uses fine patterning of the electrodes on both substrates.
The integrated circuit is a patterned piece of silicon or other type of semiconducting material. A modern IC contains millions or even billions of tiny transistors. Their tiny size allows for the fabrication of smaller, faster, more efficient, and less expensive electronic circuits. The driver chips addressing electronics displays are ICs.
Often PCBAs are connected to the display with flexible printed circuits. It’s also possible to mount all necessary components on FPCs without the need of a PCBA in the display module.
Low Voltage Differential Signaling (LVDS) is an interface to the display, not a display technology itself. This technology is not specific to displays, as it’s used in many other applications as well. It’s a high-speed signal that provides some noise immunity for the display. It also allows for longer distances compared to parallel interfaces.
As display resolutions increase, data transmission rates must increase as well. At high frequencies, single-ended signaling circuits can begin to act as antennas to radiate and receive radiated noise. Low Voltage Differential Signaling (LVDS) addresses many of these shortcomings by using differential signaling at low voltages to transmit display data at high speeds.
Mobile Industry Processor Interface (MIPI®) is a high-speed Display Serial Interface (DSI) between the host processor and the display module. It has a low pin count, high bandwidth, and low Electro Magnetic Interference (EMI), and is commonly used in cameras, cell phones and tablets.
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NVD’s state-of-the-art factories are equipped to build solutions using a wide range of display and touch technologies. To view our extensive portfolio, visit our Products Page.
With industry-leading certifications and expert engineers on staff, NVD can handle your design needs, even for the most rigorous and complex end environments. To learn more about what makes us the display manufacturer for your needs, contact us today.
In market, LCD means passive matrix LCDs which increase TN (Twisted Nematic), STN (Super Twisted Nematic), or FSTN (Film Compensated STN) LCD Displays. It is a kind of earliest and lowest cost display technology.
LCD screens are still found in the market of low cost watches, calculators, clocks, utility meters etc. because of its advantages of low cost, fast response time (speed), wide temperature range, low power consumption, sunlight readable with transflective or reflective polarizers etc. Most of them are monochrome LCD display and belong to passive-matrix LCDs.
TFT LCDs have capacitors and transistors. These are the two elements that play a key part in ensuring that the TFT display monitor functions by using a very small amount of energy without running out of operation.
Normally, we say TFT LCD panels or TFT screens, we mean they are TN (Twisted Nematic) Type TFT displays or TN panels, or TN screen technology. TFT is active-matrix LCDs, it is a kind of LCD technologies.
TFT has wider viewing angles, better contrast ratio than TN displays. TFT display technologies have been widely used for computer monitors, laptops, medical monitors, industrial monitors, ATM, point of sales etc.
Actually, IPS technology is a kind of TFT display with thin film transistors for individual pixels. But IPS displays have superior high contrast, wide viewing angle, color reproduction, image quality etc. IPS screens have been found in high-end applications, like Apple iPhones, iPads, Samsung mobile phones, more expensive LCD monitors etc.
Both TFT LCD displays and IPS LCD displays are active matrix displays, neither of them can produce color, there is a layer of RGB (red, green, blue) color filter in each LCD pixels to make LCD showing colors. If you use a magnifier to see your monitor, you will see RGB color. With switch on/off and different level of brightness RGB, we can get many colors.
Neither of them can’t release color themselves, they have relied on extra light source in order to display. LED backlights are usually be together with them in the display modules as the light sources. Besides, both TFT screens and IPS screens are transmissive, it will need more power or more expensive than passive matrix LCD screens to be seen under sunlight. IPS screens transmittance is lower than TFT screens, more power is needed for IPS LCD display.
This type of LCD was invented at the Brown Boveri Research Center, Baden, Switzerland, in 1983.twisted nematic (TN) LCDs with a 90 degrees twisted structure of the molecules have a contrast vs. voltage characteristic unfavorable for passive-matrix addressing as there is no distinct threshold voltage. STN displays, with the molecules twisted from 180 to 270 degrees, have superior characteristics.
The main advantage of STN LCDs is their more pronounced electro-optical threshold allowing for passive-matrix addressing with many more lines and columns. For the first time, a prototype STN matrix display with 540x270 pixels was made by Brown Boveri (today ABB) in 1984, which was considered a breakthrough for the industry.
STN LCDs require less power and are less expensive to manufacture than TFT LCDs, another popular type of LCD that has largely superseded STN for mainstream laptops. STN displays typically suffer from lower image quality and slower response time than TFT displays. However, STN LCDs can be made purely reflective for viewing under direct sunlight. STN displays are used in some inexpensive mobile phones and informational screens of some digital products. In the early 1990s, they had been used in some portable computers such as Amstrad"s PPC512 and PPC640, and in Nintendo"s Game Boy.
CSTN (color super-twist nematic) is a color form for electronic display screens originally developed by Sharp Electronics. The CSTN uses red, green and blue filters to display color. The original CSTN displays developed in the early 1990s suffered from slow response times and ghosting (where text or graphic changes are blurred because the pixels cannot turn off and on fast enough). Recent advances in the technology, however, have made CSTN a viable alternative to active matrix displays. New CSTN displays offer 100ms response times (for comparison TFT displays offer 8ms or less), a 140 degree viewing angle and high-quality color rivaling TFT displays – all at about half the cost. A newer passive-matrix technology called High-Performance Addressing (HPA) offers even better response times and contrast than CSTN.
Samsung had two proprietary technologies for STN LCDs, Ultra Fine & Bright (UFB), which delivered wide viewing angle (about 120 degrees), faster response time (about 60 ms) and less power consumption, while Ultra Fine & High Speed (UFS), delivered almost same color depths as TFT LCDs, greater color purity, much faster response time (about 14 ms) and same contrast ratio as TFT LCDs.
Dual Scan STN: An enhanced STN passive matrix LCD. The screen is divided into halves, and each half is scanned simultaneously, thereby doubling the number of lines refreshed per second and providing a sharper appearance. DSTN was widely used on earlier laptops. See STN and LCD.
FSTN: Film compensated STN, Formulated STN or Filtered STN. A passive matrix LCD technology that uses a film compensating layer between the STN display and rear polarizer for added sharpness and contrast. It was used in laptops before the DSTN method became popular and many early 21st Century cellphones.
CCSTN: Color Coded Super Twist Nematic. An LCD capable of displaying a limited range of colours, used in some digital organisers and graphic calculators in the 1990s
Scheffer, T. J.; Nehring, J. (1984-11-15). "A new, highly multiplexable liquid crystal display". Applied Physics Letters. AIP Publishing. 45 (10): 1021–1023. Bibcode:1984ApPhL..45.1021S. doi:10.1063/1.95048. ISSN 0003-6951.
LCD is the abbreviation for liquid crystal display. An LCD basically consists of two glass plates with a special liquid between them. The special attribute of this liquid is that it rotates or “twists” the plane of polarized light. This effect is influenced by the creation of an electrical field. The glass plates are thus each coated with a very thin metallic film. To obtain polarized light, you apply a polarization foil, the polarizer, to the bottom glass plate. Another foil must be applied to the bottom glass plate, but this time with a plane of polarization twisted by 90°. This is referred to as the analyzer.
In the idle state, the liquid twists the plane of polarization of the incoming light by 90° so that it can pass the analyzer unhindered. The LCD is thus transparent. If a specific voltage is applied to the metallic film coating, the crystals rotate in the liquid. This twists the plane of polarization of the light by another 90°, for example: The analyzer prevents the light getting through, and the LCD thus becomes opaque.TN, STN, FSTN, blue mode, yellow-green mode
Liquids that twist the plane of polarized light by 90° are referred to as TN (Twisted Nematic). STN (Super Twisted Nematic) liquids twist the plane of polarized light by at least 180°. This gives the display improved contrast. However, this technology does color the display to a certain extent. The most common colors are referred to as yellow-green and blue mode. There is also a gray mode, which in practice is more blue than gray, however.
In order to counteract the undesired color effect, the FSTN technology uses an additional foil on the outer side, but this causes a loss of light and means that this technology is only effective with lit displays.
However, the different colors occur only in displays that are either not lit or that are lit with white light. If there is any color in the lighting (e.g. yellow-green LED lighting), it overrides the color of the display. A blue-mode LCD with yellow-green LED lighting will always appear yellow-green.Static or multiplex driving method
Small displays with a small viewing area are generally statically driven. Static displays have the best contrast and the largest possible angle of view. The TN technology fulfills its purpose to the full here (black and white display, reasonably priced). The bigger displays get, however, the more lines become necessary in static operation (e.g. graphics 128x64=8192 segments =8192 lines). Since there is not enough space on either the display or a driver IC for so many lines, multiplexing is used. The display is thus divided up into rows and columns, and there is a segment at each intersection (128+64=192 lines). Scanning takes place row by row (64x, in other words a multiplex rate of 1:64). Because only 1 row is ever active at any one time, however, the contrast and the angle of view suffer the higher the multiplex rate becomes. This makes it essential to use STN.Angle of view 6°°/12°°
Every LCD has a preferred angle of view at which the contrast of the display is at its optimum. Most displays are produced for the 6°° angle of view, which is also known as the bottom view (BV). This angle corresponds to that of a pocket calculator that is lying flat on a desktop.
12°° displays (top view, TV) are best built into a table-top unit. All displays can be read vertically from the front.Reflective, transflective, transmissive
However, the lighting also determines the optical impression made by the display, and the display mode; blue or yellow-green – does not always have an influence. Below you can see the EAP162-3N display with different types of lighting by way of example:Lighting
Standard LCDs have a temperature range of 0 to +50°C. High-temperature displays are designed for operation in the range from -20 to +70°C. In this case, however, additional supply voltage is generally required. Since the contrast of any LCD is dependent on the temperature, a special temperature-compensation circuit is needed in order to use the entire temperature range, and this is particularly true for high-temperature displays (-20 to +70°C). Manual adjustment is possible but rather impractical for the user.
However, the storage temperature of a display should never be exceeded under any circumstances. An excessively high temperature can destroy the display very quickly. Direct exposure to the sun, for example, can destroy an LCD: This is because an LCD becomes darker (in positive mode) as it gets hotter. As it gets darker, it absorbs more light and converts it to heat. As a result, the display becomes even hotter and darker... In this way, temperatures of over 100°C can quickly be reached.Dot-matrix, graphics and 7-segment displays
The first LCDs were 7-segment displays, and they are still found today in simple pocket calculators and digital watches. 7 segments allow all of the digits from 0 to 9 to be displayed.
Text displays require what is known as a dot matrix, an area consisting of 5x7=35 dots, in order to display all of the letters in the alphabet as well as various special characters. Graphics displays have a similar structure to text displays. In this case, however, there are no spaces between the lines and characters.Display drivers and controllers
The semiconductor industry now offers a very large range of LCD drivers. We generally distinguish between pure display drivers without intelligence of their own, controllers with a display memory and possibly a character set, and micro-controllers with integrated LC drivers.
Pure display drivers work in a similar way to a shift register. They generally have a serial input. They require an external pulse, and in multiplex operation with high frequency they require new display data continuously in order to achieve a refresh frequency that is as high as possible (MSM5219, UPD7225, HD44100, LC7942, etc.). An example of a genuine controller is theHD44780 for dot-matrix displays: Once it has received the ASCII code, the controller manages its character set, memory and multiplexing entirely on its own. The following controllers are widely used for graphics displays: HD61202/3, HD61830, SED1520, SED1330, T6963.
Many ask themselves, "What is the difference between an LCD display and a TFT display?" or "What is the difference between a TFT and an OLED display?". Here are these 3 sometimes extremely different display technologies briefly explained. LCD vs. TFT vs. OLED (comparison).
- The LCD (Liquid Crystal Display) is a passive display technology. The operation and the structure are described above. Passive means that an LCD can only darken or let out light. So it always depends on ambient light or a backlight. This can be an advantage because the power consumption of a LCD display is very, very low. Sometimes even less than the accumulated power consumption of an E-paper display, which in static operation requires absolutely no energy to maintain the content. To change the contents, however, a relatively large amount of power is required for an E-paper display.
LCDs can also be reflective, so they reflect incident light and are therefore legible even at maximum brightness (sunlight, surgical lighting). Compared to TFT and also OLED, they have an unbeatable advantage in terms of readability and power consumption :; the "formula" is: Sunlight = LCD.
- A TFT display (of Thin-Film Transistor) is usually a color display (RGB). From the construction and the technology it corresponds to the LCD. It is also passive, so it needs a backlight. This is in any case necessary except for a few, very expensive constructions. However, a TFT needs much more light than the monochrome relatives, because the additional structures on the glass as well as the additional color filters "swallow" light. So TFTs are not particularly energy-efficient, but can display in color and at the same time the resolution is much higher.
- OLED displays (by Organic-Light-Emitting-Diode) are as the name implies active displays - every pixel or sign generates light. This achieves an extremely wide viewing angle and high contrast values. The power consumption is dependent on the display content. Here OLEDs to TFTs and LCDs differ significantly, which have a nearly constant power consumption even with different display contents. Unfortunately, the efficiency of converting the electric current into light energy is still very poor. This means that the power consumption of OLEDs with normal content is sometimes higher than that of a TFT with the same size. Colored OLEDs are increasingly used in consumer devices, but for the industry, due to their availability and lifetime, currently only monochrome displays are suitable (usually in yellow color).
In the reaction time, the OLEDs beat each TFT and LCD by worlds. Trise and Tfall are about 10μs, which would correspond to a theoretical refresh rate of 50,000 Hz. Possibly an advantage in very special applications.
Finally the question "What is better, LCD, OLED or TFT?" Due to the physical differences you can not answer that blanket. Depending on the application, there are pros and cons to each individual technology. In addition to the above differences, there are many more details in the design and construction that need to be individually illuminated for each device. Write us an e-mail or call us: we have specialists with some 20- and 30-year experience. We are happy to compare different displays together with you.AACS and IPS technology
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Dr Pan: Hello, Greg. STN is the abbreviation for Super Twisted Nematic. The main difference between TN, HTN, STN and FSTN LCD is the view angle. From the definition, the maximum view angle of STN LCD is 210~255 degree. Take this STN positive LCD for example. The view angle is 12 o’clock direction and it can be seen very clearly in the full view angle: 12 o’clock direction, 3 o’clock direction, 6 o’clock direction, 9 o’clock direction and the front side.
When it is a positive and reflective display, it can display without LED backlight; when it is a positive and transmissive/ transflective display, it can’t display without LED backlight, we have two options for the background color: grey background and blue letters, yellow-green background and black/blue letters.
When it is a negative and transmissive/ transflective display, it can’t display without LED backlight, the background is blue and the color of the letters is the color of LED backlight.
By the way, no matter it is a positive or negative display, the background color is affected by the color of LED backlight on some level. That is why the color of LED backlight is usually white.