working of tft display price
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.
Before you get a new monition for your organization, comparing the TFT display vs IPS display is something that you should do. You would want to buy the monitor which is the most advanced in technology. Therefore, understanding which technology is good for your organization is a must. click to view the 7 Best Types Of Display Screens Technology.
Technology is changing and becoming advanced day by day. Therefore, when you are looking to get a new monitor for your organization, LCD advantages, and disadvantage, you have to be aware of the pros and cons of that monitor. Moreover, you need to understand the type of monitor you are looking to buy.
Now, understanding the technology from the perspective of a tech-savvy person may not be the ideal thing to do unless you are that tech-savvy person. If you struggle to understand technology, then understanding it in a layman’s language would be the ideal thing to do.
That is why it is important to break it down and discuss point by point so that you can understand it in a layman’s language devoid of any technical jargon. Therefore, in this very article, let’s discuss what exactly TFT LCDs and IPS LCDs are, and what are their differences? You will also find out about their pros and cons for your organization.
The word TFT means Thin-Film-Translator. Click to view: what is TFT LCD, It is the technology that is used in LCD or Liquid Crystal Display. Here you should know that this type of LCD is also categorically referred to as active-matrix LCDs. It tells that these LCDs can hold back some pixels while using other pixels. So, the LCD will be using a very minimum amount of energy to function. TFT LCDs have capacitors and transistors. These are the two elements that play a key part in ensuring that the display monitor functions by using a very small amount of energy without running out of operation.
Now, it is time to take a look at its features that are tailored to improve the experience of the monitor users significantly. Here are some of the features of the TFT monitor;
The display range covers the application range of all displays from 1 inch to 40 inches as well as the large projection plane and is a full-size display terminal.
Display quality from the simplest monochrome character graphics to high resolution, high color fidelity, high brightness, high contrast, the high response speed of a variety of specifications of the video display models.
No radiation, no scintillation, no harm to the user’s health. In particular, the emergence of TFT LCD electronic books and periodicals will bring humans into the era of a paperless office and paperless printing, triggering a revolution in the civilized way of human learning, dissemination, and recording.
It can be normally used in the temperature range from -20℃ to +50℃, and the temperature-hardened TFT LCD can operate at low temperatures up to -80 ℃. It can not only be used as a mobile terminal display, or desktop terminal display but also can be used as a large screen projection TV, which is a full-size video display terminal with excellent performance.
The manufacturing technology has a high degree of automation and good characteristics of large-scale industrial production. TFT LCD industry technology is mature, a mass production rate of more than 90%.
It is a perfect combination of large-scale semiconductor integrated circuit technology and light source technology and has great potential for further development.
TFT LCD screen from the beginning of the use of flat glass plate, its display effect is flat right angles, let a person have a refreshing feeling. And LCDs are easier to achieve high resolution on small screens.
The word IPS refers to In-Plane-Switching which is a technology used to improve the viewing experience of the usual TFT displays. You can say that the IPS display is a more advanced version of the traditional TFT LCD module. However, the features of IPS displays are much more advanced and their applications are very much widespread. You should also know that the basic structure of the IPS LCD is the same as TFT LCD if you compare TFT LCD vs IPS.
As you already know, TFT displays do have a very quick response time which is a plus point for it. But, that does not mean IPS displays a lack of response time. In fact, the response time of an IPS LCD is much more consistent, stable, and quick than the TFT display that everyone used to use in the past. However, you will not be able to gauge the difference apparently by watching TFT and IPS displays separately. But, once you watch the screen side-by-side, the difference will become quite clear to you.
The main drawback of the TFT displays as figured above is the narrow-angle viewing experience. The monitor you buy for your organization should give you an experience of wide-angle viewing. It is very much true if you have to use the screen by staying in motion.
So, as IPS displays are an improved version of TFT displays the viewing angle of IPS LCDs is very much wide. It is a plus point in favor of IPS LCDs when you compare TFT vs IPS. With a TFT screen, you cannot watch an image from various angles without encountering halo effects, blurriness, or grayscale that will cause problems for your viewing.
It is one of the major and remarkable differences between IPS and TFT displays. So, if you don’t want to comprise on the viewing angles and want to have the best experience of viewing the screen from wide angles, the IPS display is what you want. The main reason for such a versatile and wonderful viewing angle of IPS display is the screen configuration which is widely set.
Now, when you want to achieve wide-angle viewing with your display screen, you need to make sure it has a faster level of frequency transmittance. It is where IPS displays overtake TFT displays easily in the comparison because the IPS displays have a much faster and speedier transmittance of frequencies than the TFT displays.
Now the transmittance difference between TFT displays and IPS displays would be around 1ms vs. 25ms. Now, you might think that the difference in milliseconds should not create much of a difference as far as the viewing experience is concerned. Yes, this difference cannot be gauged with a naked eye and you will find it difficult to decipher the difference.
However, when you view and an IPS display from a side-by-side angle and a TFT display from a similar angle, the difference will be quite evident in front of you. That is why those who want to avoid lagging in the screen during information sharing at a high speed; generally go for IPS displays. So, if you are someone who is looking to perform advanced applications on the monitor and want to have a wider viewing angle, then an IPS display is the perfect choice for you.
As you know, the basic structure of the IPS display and TFT displays are the same. So, it is quite obvious that an IPS display would use the same basic colors to create various shades with the pixels. However, there is a big difference with the way a TFT display would produce the colors and shade to an IPS display.
The major difference is in the way pixels get placed and the way they operate with electrodes. If you take the perspective of the TFT display, its pixels function perpendicularly once the pixels get activated with the help of the electrodes. It does help in creating sharp images.
But the images that IPS displays create are much more pristine and original than that of the TFT screen. IPS displays do this by making the pixels function in a parallel way. Because of such placing, the pixels can reflect light in a better way, and because of that, you get a better image within the display.
As the display screen made with IPS technology is mostly wide-set, it ensures that the aspect ratio of the screen would be wider. This ensures better visibility and a more realistic viewing experience with a stable effect.
As you already know the features of both TFT and IPS displays, it would be easier for you to understand the difference between the two screen-types. Now, let’s divide the matters into three sections and try to understand the basic differences so that you understand the two technologies in a compressive way. So, here are the difference between an IPS display and a TFT display;
Now, before starting the comparison, it is quite fair to say that both IPS and TFT displays have a wonderful and clear color display. You just cannot say that any of these two displays lag significantly when it comes to color clarity.
However, when it comes to choosing the better display on the parameter of clarity of color, then it has to be the IPS display. The reason why IPS displays tend to have better clarity of color than TFT displays is a better crystal oriental arrangement which is an important part.
That is why when you compare the IPS LCD with TFT LCD for the clarity of color, IPS LCD will get the nod because of the better and advanced technology and structure.
IPS displays have a wider aspect ratio because of the wide-set configuration. That is why it will give you a better wide-angle view when it comes to comparison between IPS and TFT displays. After a certain angle, with a TFT display, the colors will start to get a bit distorted.
But, this distortion of color is very much limited in an IPS display and you may see it very seldom after a much wider angle than the TFT displays. That is why for wide-angle viewing, TFT displays will be more preferable.
When you are comparing TFT LCD vs. IPS, energy consumption also becomes an important part of that comparison. Now, IPS technology is a much advanced technology than TFT technology. So, it is quite obvious that IPS takes a bit more energy to function than TFT.
Also, when you are using an IPS monitor, the screen will be much larger. So, as there is a need for much more energy for the IPS display to function, the battery of the device will drain faster. Furthermore, IPS panels cost way more than TFT display panels.
1. The best thing about TFT technology is it uses much less energy to function when it is used from a bigger screen. It ensures that the cost of electricity is reduced which is a wonderful plus point.
2. When it comes to visibility, the TFT technology enhances your experience wonderfully. It creates sharp images that will have no problems for older and tired eyes.
1. One of the major problems of TFT technology is that it fails to create a wider angle of view. As a result, after a certain angle, the images in a TFT screen will distort marring the overall experience of the user.
Although IPS screen technology is very good, it is still a technology based on TFT, the essence of the TFT screen. Whatever the strength of the IPS, it is a TFT-based derivative.
Finally, as you now have a proper understanding of the TFT displays vs IPS displays, it is now easier for you when it comes to choose one for your organization. Technology is advancing at a rapid pace. You should not be surprised if you see more advanced display screens in the near future. However, so far, TFT vs IPS are the two technologies that are marching ahead when it comes to making display screens.
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A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technologyactive matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.
In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark"s ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968. In 1971, Lechner, F. J. Marlowe, E. O. Nester and J. Tults demonstrated a 2-by-18 matrix display driven by a hybrid circuit using the dynamic scattering mode of LCDs.T. Peter Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories developed a CdSe (cadmium selenide) TFT, which they used to demonstrate the first CdSe thin-film-transistor liquid-crystal display (TFT LCD).active-matrix liquid-crystal display (AM LCD) using CdSe TFTs in 1974, and then Brody coined the term "active matrix" in 1975.high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.
The liquid crystal displays used in calculators and other devices with similarly simple displays have direct-driven image elements, and therefore a voltage can be easily applied across just one segment of these types of displays without interfering with the other segments. This would be impractical for a large display, because it would have a large number of (color) picture elements (pixels), and thus it would require millions of connections, both top and bottom for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns, reducing the connection count from millions down to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge that is being applied to each pixel from being drained between refreshes to a display"s image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers.
The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process.
Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce.
The twisted nematic display is one of the oldest and frequently cheapest kind of LCD display technologies available. TN displays benefit from fast pixel response times and less smearing than other LCD display technology, but suffer from poor color reproduction and limited viewing angles, especially in the vertical direction. Colors will shift, potentially to the point of completely inverting, when viewed at an angle that is not perpendicular to the display. Modern, high end consumer products have developed methods to overcome the technology"s shortcomings, such as RTC (Response Time Compensation / Overdrive) technologies. Modern TN displays can look significantly better than older TN displays from decades earlier, but overall TN has inferior viewing angles and poor color in comparison to other technology.
Most TN panels can represent colors using only six bits per RGB channel, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available using 24-bit color. Instead, these panels display interpolated 24-bit color using a dithering method that combines adjacent pixels to simulate the desired shade. They can also use a form of temporal dithering called Frame Rate Control (FRC), which cycles between different shades with each new frame to simulate an intermediate shade. Such 18 bit panels with dithering are sometimes advertised as having "16.2 million colors". These color simulation methods are noticeable to many people and highly bothersome to some.gamut (often referred to as a percentage of the NTSC 1953 color gamut) are also due to backlighting technology. It is not uncommon for older displays to range from 10% to 26% of the NTSC color gamut, whereas other kind of displays, utilizing more complicated CCFL or LED phosphor formulations or RGB LED backlights, may extend past 100% of the NTSC color gamut, a difference quite perceivable by the human eye.
The transmittance of a pixel of an LCD panel typically does not change linearly with the applied voltage,sRGB standard for computer monitors requires a specific nonlinear dependence of the amount of emitted light as a function of the RGB value.
In-plane switching was developed by Hitachi Ltd. in 1996 to improve on the poor viewing angle and the poor color reproduction of TN panels at that time.
Initial iterations of IPS technology were characterised by slow response time and a low contrast ratio but later revisions have made marked improvements to these shortcomings. Because of its wide viewing angle and accurate color reproduction (with almost no off-angle color shift), IPS is widely employed in high-end monitors aimed at professional graphic artists, although with the recent fall in price it has been seen in the mainstream market as well. IPS technology was sold to Panasonic by Hitachi.
Most panels also support true 8-bit per channel color. These improvements came at the cost of a higher response time, initially about 50 ms. IPS panels were also extremely expensive.
IPS has since been superseded by S-IPS (Super-IPS, Hitachi Ltd. in 1998), which has all the benefits of IPS technology with the addition of improved pixel refresh timing.
In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan"s Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation.
It achieved pixel response which was fast for its time, wide viewing angles, and high contrast at the cost of brightness and color reproduction.Response Time Compensation) technologies.
Less expensive PVA panels often use dithering and FRC, whereas super-PVA (S-PVA) panels all use at least 8 bits per color component and do not use color simulation methods.BRAVIA LCD TVs offer 10-bit and xvYCC color support, for example, the Bravia X4500 series. S-PVA also offers fast response times using modern RTC technologies.
When the field is on, the liquid crystal molecules start to tilt towards the center of the sub-pixels because of the electric field; as a result, a continuous pinwheel alignment (CPA) is formed; the azimuthal angle rotates 360 degrees continuously resulting in an excellent viewing angle. The ASV mode is also called CPA mode.
A technology developed by Samsung is Super PLS, which bears similarities to IPS panels, has wider viewing angles, better image quality, increased brightness, and lower production costs. PLS technology debuted in the PC display market with the release of the Samsung S27A850 and S24A850 monitors in September 2011.
TFT dual-transistor pixel or cell technology is a reflective-display technology for use in very-low-power-consumption applications such as electronic shelf labels (ESL), digital watches, or metering. DTP involves adding a secondary transistor gate in the single TFT cell to maintain the display of a pixel during a period of 1s without loss of image or without degrading the TFT transistors over time. By slowing the refresh rate of the standard frequency from 60 Hz to 1 Hz, DTP claims to increase the power efficiency by multiple orders of magnitude.
Due to the very high cost of building TFT factories, there are few major OEM panel vendors for large display panels. The glass panel suppliers are as follows:
External consumer display devices like a TFT LCD feature one or more analog VGA, DVI, HDMI, or DisplayPort interface, with many featuring a selection of these interfaces. Inside external display devices there is a controller board that will convert the video signal using color mapping and image scaling usually employing the discrete cosine transform (DCT) in order to convert any video source like CVBS, VGA, DVI, HDMI, etc. into digital RGB at the native resolution of the display panel. In a laptop the graphics chip will directly produce a signal suitable for connection to the built-in TFT display. A control mechanism for the backlight is usually included on the same controller board.
The low level interface of STN, DSTN, or TFT display panels use either single ended TTL 5 V signal for older displays or TTL 3.3 V for slightly newer displays that transmits the pixel clock, horizontal sync, vertical sync, digital red, digital green, digital blue in parallel. Some models (for example the AT070TN92) also feature input/display enable, horizontal scan direction and vertical scan direction signals.
New and large (>15") TFT displays often use LVDS signaling that transmits the same contents as the parallel interface (Hsync, Vsync, RGB) but will put control and RGB bits into a number of serial transmission lines synchronized to a clock whose rate is equal to the pixel rate. LVDS transmits seven bits per clock per data line, with six bits being data and one bit used to signal if the other six bits need to be inverted in order to maintain DC balance. Low-cost TFT displays often have three data lines and therefore only directly support 18 bits per pixel. Upscale displays have four or five data lines to support 24 bits per pixel (truecolor) or 30 bits per pixel respectively. Panel manufacturers are slowly replacing LVDS with Internal DisplayPort and Embedded DisplayPort, which allow sixfold reduction of the number of differential pairs.
Backlight intensity is usually controlled by varying a few volts DC, or generating a PWM signal, or adjusting a potentiometer or simply fixed. This in turn controls a high-voltage (1.3 kV) DC-AC inverter or a matrix of LEDs. The method to control the intensity of LED is to pulse them with PWM which can be source of harmonic flicker.
The bare display panel will only accept a digital video signal at the resolution determined by the panel pixel matrix designed at manufacture. Some screen panels will ignore the LSB bits of the color information to present a consistent interface (8 bit -> 6 bit/color x3).
With analogue signals like VGA, the display controller also needs to perform a high speed analog to digital conversion. With digital input signals like DVI or HDMI some simple reordering of the bits is needed before feeding it to the rescaler if the input resolution doesn"t match the display panel resolution.
The statements are applicable to Merck KGaA as well as its competitors JNC Corporation (formerly Chisso Corporation) and DIC (formerly Dainippon Ink & Chemicals). All three manufacturers have agreed not to introduce any acutely toxic or mutagenic liquid crystals to the market. They cover more than 90 percent of the global liquid crystal market. The remaining market share of liquid crystals, produced primarily in China, consists of older, patent-free substances from the three leading world producers and have already been tested for toxicity by them. As a result, they can also be considered non-toxic.
Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.
Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.
Richard Ahrons (2012). "Industrial Research in Microcircuitry at RCA: The Early Years, 1953–1963". 12 (1). IEEE Annals of the History of Computing: 60–73. Cite journal requires |journal= (help)
K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.
Kim, Sae-Bom; Kim, Woong-Ki; Chounlamany, Vanseng; Seo, Jaehwan; Yoo, Jisu; Jo, Hun-Je; Jung, Jinho (15 August 2012). "Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa". Journal of Hazardous Materials. Seoul, Korea; Laos, Lao. 227–228: 327–333. doi:10.1016/j.jhazmat.2012.05.059. PMID 22677053.
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
LCDs without lighting are hard to imagine these days. However, since there are basically four different types of lighting, the type selected depends very much on the application. Here is a brief overview to clarify the situation:LED
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