TFT Display Technologies and IPS display technologies
This article about TFT display technologies was written by Julia Nielsen.
Julia Nielsen is a jack-of-all-trades writer, having written for newspapers, magazines, websites, and blogs for the last 15 years. When she’s not dabbling in the written world, she’s spending time with her beautiful granddaughter. She loves to hear from readers, especially when they offer chocolate.
The two buzzwords the tech world has been chatting about for a number of years now is IPS, (In-Plane Switching) screen technology used for liquid crystal displays or LCD’s for short, and TFT (Thin-Film-Transistor) an active matrix screen technology, which is more expensive, but a sharper image.
Designed in the 1980’s, but not introduced until nearly a decade later, in 1996, by Hitachi, IPS technology is nothing new, and a type of LCD design that affords greater viewing angles and higher-quality color reproduction than the traditional TN or Twisted Nematic LCDs.
When Apple brought it to the public’s attention, it took off, and as they say, the rest is history; but, it really didn’t become widespread or worldwide until just the late 1990’s. Since then, IPS screens have been implemented in homes all over the world, with variations to suit one’s electronic needs.
What is a TFT?
TFT (Thin-Film-Transistor) Liquid Crystal Display is a thin display type, where a transistor embedded into each crystal gate; these transistors are then printed on thin-transparent film. The technology was designed to improve image qualities, such as contrast and addressability.
Also designed in the late 1980’s, TFT display technologies is just another variation of LCD displays that offer greater color, contrast, and response times as opposed to available passive matrix LCD’s. One of the primary differences between IPS and TFT display technologies is the cost. IPS is more expensive than TN technology. However, there are some key differences between the two that should be noted.
IPS & TFT Display Features
Before we go into the differences, let’s talk about features of each technology. Note that we’re not talking TVs, computer, or tablets, but screens on a much smaller scale, (think 7” or smaller) which uses different rules to fit that scale. First, it’s interesting to discover that the TFT display technologies is the most common type of color display technology; more monochrome displays still out-sell color, due to lower cost and lower power consumption, however, the narrow poor visibility of TFTs in direct sunlight is their downside; but I’m getting ahead of myself here.
IPS technology has come a long way in regards to cell phones and other LCD screens that are even much smaller. (Picture digital clocks on a radio, microwave, and hand-held games) Some of the features of an IPS screen include:
- Wider viewing angles – crystals are aligned horizontally rather than vertically, so it allows for better angled viewing, perfect for smaller screens, where you need to rotate the screen for better viewing
- Lower power consumption, resulting in longer battery life – again for smaller screens, this works great, because even though this technology requires more power, a smaller screen has less power drain.
- Brilliant color image – this is a huge advance in technology, from a Twisted Nematic (TN) display that only produced 6-bit color, to an 8-bit color display with the IPS technology
- Variations to help with user’s viewing requirements or desires – there are several different forms of IPS technology: Super-IPS, (S-IPS) Advanced Super IPS, Advanced S-IPS, where the liquid crystal molecules stay parallel to the front and back panels, instead of perpendicular when a voltage is applied
- Consistent, accurate color, under different viewing angles
- Clear images and stable response time, which allows for faster response time – good for videos.
TFT display technologies have developed over the years and have become quite popular in tech circles. The features offered with this advancing technology are:
- Superior color display – for technology that requires it or for consumers that desire color screens
- Not only is the color superb, but the clarity outstanding
- Features a longer half-life, (half-life is the amount of time in hours before the display is 50% as bright as when it was first turned on), than OLEDs and comes in varying sizes, from under an inch up to over 15 inches
- Capacitive Touchscreen or touch panel, which is in the majority of Smartphones and allows for additional functionality, specifically for zooming and scrolling
- Resistive touch panel which is lower in cost and are usually standard on most TFT devices
- Aspect ratio control, which refers to a screen’s ability to maintain an aspect ratio of a source image at the hardware level, and 1:1 pixel mapping, used to literally “map” the exact number of pixels specifically in the source resolution to pixels on the screen
- No “ghosting” (ghosting is when an image will stay on for a short time when instead it should be off)
- Variety of displays, which can be interfaced through a variety of bus types, including 18 and 24 bit for red/green/blue, LVDS, and 8 bit and 16 bit for a CPU – many controllers allow for two or more different types of interfaces on the same TFT screen
Differences between two similar display technologies
Okay, now that we’ve covered the features of both technologies, let’s look at the differences between the two. Before we get into the spec differences, let’s first address the main difference: the arrangement of transistors and liquid crystal. Seems vague, doesn’t it?
Let me explain. As you can see, both have excellent color display and clarity; however, IPS screens offer greater color reproduction and viewing angles because of the way crystal orientation and polarizers are arranged. In a TFT screen, the structure of the crystals results in angular retardation in the light. The IPS screens thus offer less distortion properties. Other differences include power consumption and cost. With IPS screens, it takes more power (up to 15% more) than with a TFT screen. If you’re on a monitor, such as a computer screen that’s bigger than 7 inches, it will drain your battery faster than if you’re on a 3.5” screen. Regarding cost, IPS panels are more expensive to produce than TFT panels.
- IPS screens are popular and in high demand with professionals including surgeons and photographers or pretty much any profession that requires color reproduction, therefore, because the demand is high, the price goes up. (way to love economics) Also, less manufactures are building IPS at this time.
- The color channels increase from 6 bits (TN displays) to 8 bits (IPS displays) to ensure the precision of shades per color channel, thus increasing manufacturing costs
- Increased transistors to control crystals and a stronger light source results in higher costs
- Stronger light source means increased electricity, which trickles down to more heat, thus higher electrical bills
If you want the benefits of having a Smartphone without a huge price tag, then TFT devices are your best bet. Another difference is that IPS screens have longer response times than TFT screens, so the lag output is greater. A few other key differences to be aware of are that with IPS panels, you get a bigger variety of panels, as was discussed above, with their super, advanced, and so forth developments, giving the consumer options, and IPS screens that can display 24-bit TrueColor; they also stay color-accurate and remain stable.
Advantages & Disadvantages for use in LCD Displays
So, are you ready to delve into the pros and cons of these two technologies? Granted, we’ve touched on their features and differences, but now it’s time to ask yourself, which one is better for me or my business?
We’ve been talking largely about Smartphone screens, but since both technologies work on smaller screens, such as clocks and timers or digital thermometers, let’s focus on those.
ADVANTAGES OF IPS DISPLAY TECHNOLOGY
Because of their superior color and clarity of images, devices using an IPS screens are easy to install on walls, due to their compact form and low-depth. The Super IPS screens offer a higher angle of 170˚ for better clarity and wider viewing, particularly at night. Images remain stable and clear and not sparkly, shiny, like other screens; they also have a longer battery life and screen life, (on smaller screens of course) because of the lower electrical output. The release of heat is lower, again because of the reduced electrical consumption. The colors are also more vibrant and clear, not pixelated like other lower quality-type devices. As mentioned earlier, there are also many variations of IPS technology to suit your needs and desires.
DISADVANTAGES OF IPS DISPLAY TECHNOLOGY
Now we will go over the downside of IPS screens, which we briefly touched on above, which includes a major disadvantage: cost. If you’re just looking for an average Smartphone or don’t need all the fancy coloring and clarity for LCD displays, then cost may not be a big factor; however, this is the main reason why IPS technology is beginning to come down. As with every new invention, discovery or technology, demand is everything. Another disadvantage is that colors may not always transcribe correctly or accurately, which may or may not be a deterrent. Also, high resolutions are not always readily available for personal applications. In certain circumstances, the brightness may not be enough, especially in darkness.
ADVANTAGES OF TFT DISPLAY TECHNOLOGIES
Steve Jobs said it best: “Design is not just what it looks like and feels like. Design is how it works.” I tend to agree with him. With TFT display technologies, less energy consumption is a big deal, especially when dealing with bigger screens, and of course less electricity means lower cost, overall. The visibility is sharper, meaning no geometric distortion, which is great for these tired, old eyes. The response time and physical design of the screens are also appealing. TFT displays can also save space and be placed virtually anywhere in an office or home, because of the brightly lit feature and crisp clear images.
DISADVANTAGES OF TFT DISPLAY TECHNOLOGIES
Some cons of TFT screens deal with the viewing angle, which create distortion, resulting in a less-than-perfect image. Static resolution, meaning the resolution can’t be changed, may also cause a problem, but newer models seem to have tackled that issue. The accuracy of the display of colors is not perfect, specifically strong blacks and bright whites, so when printing an image, it may not display the spectrum of colors.
And there you have it. In the future, even this superb technology will change and new, more exciting technology will take its place. But until then, IPS & TFT screens are forging ahead with their own advances and improvements, so stayed tune. You don’t want to miss it.
Focus Display Solutions (www.FocusLCDs.com) offers off-the-shelf Color TFT display technologies in both TN and IPS. Many of the color modules contain built in touch panels.
FocusLCDs is an engineering-focused company and has the ability to modify LCDs to meet your unique needs.