tft lcd displays tft lcd vs oled brands

A new form of display technology called Organic Light-Emitting Diode (OLED) is sweeping the display world today. Let’s take a look at what TFT display VS OLED display and how it stacks up to TFTs.

OLED display uses a light-emitting diode (LED) that features an organic compound as its emissive electroluminescent layer. Electric current is applied to the diode, activating the organic compound film and giving off light as a result. The organic compound film is typically situated between two electrodes, one of which is transparent.

OLEDs are mostly used in smartphones and limited releases of high-end smart televisions. It can also be used in computer monitors and handheld game consoles.

OLED displays naturally emit light, so using them on a display panel doesn’t require a backlight. Meanwhile, LCDs need backlights because the liquid crystals cannot create light on their own. OLED’s natural light emission also paves the way for creating lighter screen devices than those using TFT LCD display.

LCD displays are brighter than OLED. This is due to the LCD’s use of backlights that can brightly light up the entire screen. While OLEDs emit good brightness levels from their light, they can never match the brightness that LCD backlights have.

OLED wins in the black levels feature. It’s because OLEDs can perfectly turn off a pixel, causing it to become completely black. LCDs can’t create perfect black screens even with their full-array local dimming feature. LCDs are also prone to blooming, where a bright part spoils the darkness of an adjacent black area.

OLED screens have better viewing angles than LCDs display. Some LCDs improve their viewing angles by using in-plane switching panels (IPS). However, the clarity of images and videos can’t match that of OLEDs when viewed from extreme side angles. This is because LCDs inherently block light due to their filtering layers, and that creates added depth which makes LCD viewing angles limited.

LCD displays are a bit more energy-efficient than OLEDs. Energy consumption in OLED displays depends on the screen brightness. Less brightness used means lower power consumption, but this may not be ideal because the contrast ratio will suffer when brightness is reduced. This is not ideal if, for instance, you’re using an OLED smartphone under bright sunlight.

Meanwhile, the backlights form the bulk of power consumption in TFT displays. Putting the backlight to a lower setting significantly improves the energy efficiency of TFT displays. For instance, reducing the backlight brightness of an LCD TV with a LED backlight won’t affect the picture quality but will draw less power consumption than an OLED TV.

Both OLED and LCD create high-quality images with a wide color gamut on a screen. OLED display wins over TFT display regarding blackness levels and viewing angle. However, the TFT display takes the cake for brightness and energy efficiency.

AMOLED is another emerging display technology lately. It stands for Active Matrix Organic Light-Emitting Diodes. AMOLED is a type of OLED display used in several smartphones, digital cameras, televisions, and media players.

Thin film transistors (TFTs) and capacitors are attached to each pixel LED component of the panel. At least two TFTs are attached to one pixel – one to control the capacitor’s charging and another to give a voltage source.

AMOLED displays have better color accuracy than LCDs. What makes the color more accurate in AMOLED displays is largely due to the precise pixel control achieved by AMOLED panels.

Whites and blacks appear perfect in AMOLED displays. Whites produced by LCDs may carry a bluish tint due to the backlight. Blacks don’t completely appear dark in LCDs, too.

AMOLED provides a greater color gamut than LCDs. AMOLEDs (and all OLED displays in general) have additional blue and green saturation. While these hues greatly widen AMOLED’s color options, some people find the resulting colors a bit unnatural to look at.

Meanwhile, LCDs have subdued greens and quite compelling red hues. Its color gamutmay not be as wide as AMOLED’s, but many people still find it satisfying. That’s because LCD’s color range closely matches the Standard RBG color gamut profile, the one most utilized in videos and images.

LCD’s backlights help maintain the color balance of the entire screen. The backlights ensure that color balance remains consistent across the display. Meanwhile, AMOLED tends to suffer from very slight color balance drifts because of variances in the diodes’ light-emitting capacity over time.

LCDs often have a lower contrast ratio and are prone to light bleeds. That’s due to the backlights remaining open even if light has been blocked and the pixels are supposed to show black color. This is not a problem with AMOLED displays because the panel can simply switch off the pixel to create a pure black color. AMOLEDs have a better contrast ratio as exhibited by their pure black and white levels.

Since AMOLED displays do not require filtering layers and backlights, they’re more suited for use in handheld mobile devices such as smartphones and gaming consoles. LCD may be used in mobile devices as well, but the filtering layers and backlights tend to add a slight bulk to the device. Hence, many manufacturers are now switching to thinner and lighter AMOLED displays.

To sum up this part, AMOLED displays fare better than LCDs in terms of color gamut, accuracy, contrast, and mobile device suitability. However, LCDs have the potential for longer lifespans and carry a better color balance across the display device.

Display P3 is an Apple-developed color space heavily used in American films and digital movie projection. It allows devices to display richer, vibrant, and more lifelike colors that are demanded in videos and movies. It’s also created for adapting to computer displays.

Display P3 has a color space based on the DCI-P3 primaries. It uses the D65 white point which is typically used in color spaces for computer displays. Display P3 also utilizes the sRGB transfer curve in place of the DCI-P3’s 1/2.6 pure gamma curve.

If you compare color LCD vs Display P3, you’ll find a significantly wider color range in Display P3 than the typical sRGB used in color LCDs. LCD monitors, especially those used in computers and laptops, are configured to accurately represent the sRGB gamut as precisely as possible. Meanwhile, Display P3 has been consistently used in Apple products since 2015, starting with the iMac desktop.

That’s all the basic information you need to know about LCD display screens. And the difference between TFT Display VS OLED Display. Now, you know How LCD Works, its possible lifespan, components, and how it compares to other display technologies.

Armed with this information, you can better appreciate and take care of your LCD display devices. And in case you’re planning to add display devices to your business, the information you’ve learned will help you make educated choices regarding the display technologies you’ll utilize.

TFT LCD is a mature technology. OLED is a relatively new display technology, being used in more and more applications. As for Micro LED, it is a new generation technology with very promising future. Followings are the pros and cons of each display technology.

TFT Liquid Crystal Display is widely used these days. Since LCD itself doesn"t emit light. TFT LCD relies on white LED backlight to show content. This is an explanation of how TFT LCD works.

Relatively lower contrast：Light needs to pass through LCD glasses, liquid crystal layer, polarizers and color filters. Over 90% is lost. Also, LCD can not display pure black.

Organic Light-Emitting Diode is built from an electro-luminescent layer that contains organic compounds, which emit light in response to an electric current. There are two types of OLED, Passive Matrix OLED (PMOLED) and Active Matrix OLED (AMOLED). These driving methods are similar to LCD"s. PMOLED is controlled sequentially using a matrix addressing scheme, m + n control signals are required to address a m x n display. AMOLED uses a TFT backplane that can switch individual pixels on and off.

Low power consumption and flexible: OLED doesn"t rely on backlight and consumes less power. OLED is essentially created on plastic film. It is bendable and easy to process.

High contrast and vivid color: OLED emits light itself, can produce very bright image with beautiful color. And because OLED can be turned off, it can produce true black.

Stroboscopic effect: most OLED screen uses PWM dimming technology. Some people who are easy perceive stroboscopic frequency may have sore eyes and tears.

​Micro LED, sometimes called μLED is made up of tiny LED, measure less than 100μm. Another way of looking at this is that MicroLEDs are simply traditional LEDs shrunk down and placed into an array.

Replacing organic material with inorganic GaN material eliminates the need of polarizing and encapsulation layer, found in OLED. Micro LED is smaller and thinner, consumes less power.

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.

AMOLED and TFT are two types of display technology used in smartphones. AMOLED (active-matrix organic light-emitting diode) displays are made up of tiny organic light-emitting diodes, while TFT (Thin-Film Transistor) displays use inorganic thin-film transistors.

AMOLEDs are made from organic materials that emit light when an electric current is passed through them, while TFTs use a matrix of tiny transistors to control the flow of electricity to the display.

Refresh Rate: Another key difference between AMOLED and TFT displays is the refresh rate. The refresh rate is how often the image on the screen is updated. AMOLED screens have a higher refresh rate than TFT screens, which means that they can display images more quickly and smoothly.

Response Time: The response time is how long it takes for the pixels to change from one colour to another. AMOLED screens have a shorter response time than TFT screens..

Colour Accuracy/Display Quality: AMOLED screens are more accurate when it comes to displaying colours. This is because each pixel on an AMOLED screen emits its own light, which means that the colours are more pure and true to life. TFT screens, on the other hand, use a backlight to illuminate the pixels, which can cause the colours to appear washed out or less vibrant.

Viewing Angle: The viewing angle is the angle at which you can see the screen. AMOLED screens have a wider viewing angle than TFT screens, which means that you can see the screen from more angles without the colours looking distorted.

Power Consumption: One of the main advantages of AMOLED displays is that they consume less power than TFT displays. This is because the pixels on an AMOLED screen only light up when they need to, while the pixels on a TFT screen are always illuminated by the backlight.

Production Cost: AMOLED screens are more expensive to produce than TFT screens. This is because the manufacturing process for AMOLED screens is more complex, and the materials used are more expensive.

Availability: TFT screens are more widely available than AMOLED screens and have been around for longer. They are typically used in a variety of devices, ranging from phones to TVs.

Usage: AMOLED screens are typically used in devices where power consumption is a concern, such as phones and wearable devices. TFT screens are more commonly used in devices where image quality is a higher priority, such as TVs and monitors.

AMOLED and TFT are two different types of display technology. AMOLED displays are typically brighter and more vibrant, but they are more expensive to produce. TFT displays are cheaper to produce, but they are not as bright or power efficient as AMOLED displays.

The display technology that is best for you will depend on your needs and preferences. If you need a screen that is bright and vibrant, then an AMOLED display is a good choice. If you need a screen that is cheaper to produce, then a TFT display is a good choice. However, if you’re worried about image retention, then TFT may be a better option.

Nauticomp Inc.provides world-class fully customizable touchscreen displays for commercial and industrial settings. With features like sunlight readability, brightness adjustability, infrared lighting, full backlighting, all-weather capabilities, etc., our displays are second to none. Contact us today to learn more.

There are plenty of new and confusing terms facing TV shoppers today, but when it comes down to the screen technology itself, there are only two: Nearly every TV sold today is either LCD or OLED.

The biggest between the two is in how they work. With OLED, each pixel provides its own illumination so there"s no separate backlight. With an LCD TV, all of the pixels are illuminated by an LED backlight. That difference leads to all kinds of picture quality effects, some of which favor LCD, but most of which benefit OLED.

LCDs are made by a number of companies across Asia. All current OLED TVs are built by LG Display, though companies like Sony and Vizio buy OLED panels from LG and then use their own electronics and aesthetic design.

So which one is better? Read on for their strengths and weaknesses. In general we"ll be comparing OLED to the best (read: most expensive) LCD has to offer, mainly because there"s no such thing as a cheap OLED TV (yet).

At the other side of light output is black level, or how dark the TV can get. OLED wins here because of its ability to turn off individual pixels completely. It can produce truly perfect black.

The better LCDs have local dimming, where parts of the screen can dim independently of others. This isn"t quite as good as per-pixel control because the black areas still aren"t absolutely black, but it"s better than nothing. The best LCDs have full-array local dimming, which provides even finer control over the contrast of what"s onscreen -- but even they can suffer from "blooming," where a bright area spoils the black of an adjacent dark area.

Here"s where it comes together. Contrast ratio is the difference between the brightest and the darkest a TV can be. OLED is the winner here because it can get extremely bright, plus it can produce absolute black with no blooming. It has the best contrast ratio of any modern display.

One of the main downsides of LCD TVs is a change in picture quality if you sit away from dead center (as in, off to the sides). How much this matters to you certainly depends on your seating arrangement, but also on how much you love your loved ones.

A few LCDs use in-plane switching (IPS) panels, which have better off-axis picture quality than other kinds of LCDs, but don"t look as good as other LCDs straight on (primarily due to a lower contrast ratio).

OLED doesn"t have the off-axis issue LCDs have; its image looks basically the same, even from extreme angles. So if you have a wide seating area, OLED is the better option.

Nearly all current TVs are HDR compatible, but that"s not the entire story. Just because a TV claims HDR compatibility doesn"t mean it can accurately display HDR content. All OLED TVs have the dynamic range to take advantage of HDR, but lower-priced LCDs, especially those without local-dimming backlights, do not. So if you want to see HDR content it all its dynamic, vibrant beauty, go for OLED or an LCD with local dimming.

In our tests comparing the best new OLED and LCD TVs with HDR games and movies, OLED usually looks better. Its superior contrast and lack of blooming win the day despite LCD"s brightness advantage. In other words LCD TVs can get brighter, especially in full-screen bright scenes and HDR highlights, but none of them can control that illumination as precisely as an OLED TV.

OLED"s energy consumption is directly related to screen brightness. The brighter the screen, the more power it draws. It even varies with content. A dark movie will require less power than a hockey game or ski competition.

The energy consumption of LCD varies depending on the backlight setting. The lower the backlight, the lower the power consumption. A basic LED LCD with its backlight set low will draw less power than OLED.

LG has said their OLED TVs have a lifespan of 100,000 hours to half brightness, a figure that"s similar to LED LCDs. Generally speaking, all modern TVs are quite reliable.

Does that mean your new LCD or OLED will last for several decades like your parent"s last CRT (like the one pictured). Probably not, but then, why would you want it to? A 42-inch flat panel cost $14,000 in the late 90"s, and now a 65-inch TV with more than 16x the resolution and a million times better contrast ratio costs $1,400. Which is to say, by the time you"ll want/need to replace it, there will be something even better than what"s available now, for less money.

OLED TVs are available in sizes from 48 to 88 inches, but LCD TVs come in smaller and larger sizes than that -- with many more choices in between -- so LCD wins. At the high end of the size scale, however, the biggest "TVs" don"t use either technology.

If you want something even brighter, and don"t mind spending a literal fortune to get it, Samsung, Sony, and LG all sell direct-view LED displays. In most cases these are

You can get 4K resolution, 50-inch LCDs for around $400 -- or half that on sale. It"s going to be a long time before OLEDs are that price, but they have come down considerably.

LCD dominates the market because it"s cheap to manufacture and delivers good enough picture quality for just about everybody. But according to reviews at CNET and elsewhere, OLED wins for overall picture quality, largely due to the incredible contrast ratio. The price difference isn"t as severe as it used to be, and in the mid- to high-end of the market, there are lots of options.

Engineers should choose TFT vs OLED for new designs…and here’s why. OLED (organic light-emitting diode) technology continues to increase in popularity, but its growth has really exploded in the last few months due to such large-scale mass production of consumer products such as: e-cigarettes (personal vaporizers), smart-watches, cell phones and other wearables.

But these advantages have worked against OLEDs in new products as more and more new designs have incorporated OLEDs, increasing demand, while the supply side of this technology has failed to keep pace.

“There are only a handful of factories here in Shenzhen that produce OLED screens,” says Alex Liu, President of EC Supply Inc., a leading distributor of vape and electronic cigarette products. “These factories are extremely understaffed for the tens of millions of OLED screens that are in demand, yet everyone wants to jump on board the wearable technology craze. These factories simply lack the work force and raw materials to keep up with production of wearables, let alone fulfill relatively small orders for the vape industry in time for the holiday season.”

Adding to the OLED supply nightmare is the labor shortage in China coupled with many OEM customers increasing their order quantities in a race to beat the Chinese New year shut down.

“I strongly recommend customers purchase any MODs with OLED screens through a trusted source that can guarantee inventory.” – Alex Liu, President of EC Supply Inc.

TFT technology has been in production for several years and is here to stay. There are several TFT glass suppliers to support current demand and they have a great deal of capacity for increased demand.

Focus Displays carries TFT Displays as a standard stock item and can be shipped the same day from our online store as well as from distributor: Allied Electronics

TFT displays are also known as an “Active Matrix TFT LCD module” and have an array of thin film transistors fabricated on the glass that makes the LCD. There is one of these transistors for each pixel on the LCD.

LCDs use voltage applied to a field of microscopic liquid crystals to change the crystal’s orientation, which in turn changes the polarization of the liquid crystal which creates light or dark pixels on the display.

Beautiful, complex images: All of our TFT modules are full-color graphic displays. Unlike standard monochrome character displays, you can create complex images for an imaginative user experience.

Thin and light: These are ideal display modules for handheld devices, communications equipment, information displays, and test and measurement equipment.

Single Supply: Most of the TFTs use an integrated controller with built-in voltage generation so only a single 3.3v supply is needed for both the panel power and logic voltage.

Many of our character LCD modules use a standard HD44780 controller, so they can be quickly integrated into a new product or used as a replacement in your existing products.

Many of the LCD controllers on board our graphic LCD display modules also include a CGROM (character generator ROM) which allows for easy character information as well as full bit-mapped graphic information to be shown.

Some of the graphic LCD displays have the ability to render graphics in grayscale, enabling you to show images and elements of your UI (user interface) with more depth and definition.

Because OLEDs are emissive, these displays can always be used in dark environments. There is usually a software command or hardware setting that will allow OLEDs to be dimmed.

Some OLED displays are bright enough to be sunlight readable–these models will typically take more current and may have a shorter rated lifetime. Additionally, OLEDs have extremely wide viewing angles.

What makes OLEDs useful for display construction is that they can be fabricated in bulk. Using OLED fabrication techniques, all the diodes can be made at the same time, at a much lower cost. OLEDs also come in a wide variety of colors.

Flat-panel displays are thin panels of glass or plastic used for electronically displaying text, images, or video. Liquid crystal displays (LCD), OLED (organic light emitting diode) and microLED displays are not quite the same; since LCD uses a liquid crystal that reacts to an electric current blocking light or allowing it to pass through the panel, whereas OLED/microLED displays consist of electroluminescent organic/inorganic materials that generate light when a current is passed through the material. LCD, OLED and microLED displays are driven using LTPS, IGZO, LTPO, and A-Si TFT transistor technologies as their backplane using ITO to supply current to the transistors and in turn to the liquid crystal or electroluminescent material. Segment and passive OLED and LCD displays do not use a backplane but use indium tin oxide (ITO), a transparent conductive material, to pass current to the electroluminescent material or liquid crystal. In LCDs, there is an even layer of liquid crystal throughout the panel whereas an OLED display has the electroluminescent material only where it is meant to light up. OLEDs, LCDs and microLEDs can be made flexible and transparent, but LCDs require a backlight because they cannot emit light on their own like OLEDs and microLEDs.

Liquid-crystal display (or LCD) is a thin, flat panel used for electronically displaying information such as text, images, and moving pictures. They are usually made of glass but they can also be made out of plastic. Some manufacturers make transparent LCD panels and special sequential color segment LCDs that have higher than usual refresh rates and an RGB backlight. The backlight is synchronized with the display so that the colors will show up as needed. The list of LCD manufacturers:

Organic light emitting diode (or OLED displays) is a thin, flat panel made of glass or plastic used for electronically displaying information such as text, images, and moving pictures. OLED panels can also take the shape of a light panel, where red, green and blue light emitting materials are stacked to create a white light panel. OLED displays can also be made transparent and/or flexible and these transparent panels are available on the market and are widely used in smartphones with under-display optical fingerprint sensors. LCD and OLED displays are available in different shapes, the most prominent of which is a circular display, which is used in smartwatches. The list of OLED display manufacturers:

MicroLED displays is an emerging flat-panel display technology consisting of arrays of microscopic LEDs forming the individual pixel elements. Like OLED, microLED offers infinite contrast ratio, but unlike OLED, microLED is immune to screen burn-in, and consumes less power while having higher light output, as it uses LEDs instead of organic electroluminescent materials, The list of MicroLED display manufacturers:

Sony produces and sells commercial MicroLED displays called CLEDIS (Crystal-LED Integrated Displays, also called Canvas-LED) in small quantities.video walls.

LCDs are made in a glass substrate. For OLED, the substrate can also be plastic. The size of the substrates are specified in generations, with each generation using a larger substrate. For example, a 4th generation substrate is larger in size than a 3rd generation substrate. A larger substrate allows for more panels to be cut from a single substrate, or for larger panels to be made, akin to increasing wafer sizes in the semiconductor industry.

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Hi all, I"ve done some research on tft vs IPS screens and it seems tft screens are the worst type around. With that said, all the videos and articles I found were from 5ish years ago. Are tft screens still garbage? If so, why in the world would Motorola put it in their flagship?

Hi all, I"ve done some research on tft vs IPS screens and it seems tft screens are the worst type around. With that said, all the videos and articles I found were from 5ish years ago. Are tft screens still garbage? If so, why in the world would Motorola put it in their flagship?

I have noticed that distributors for small and medium TFT, they consider TFT still a top quality product, it"s enough to see product list of any online distributor like

Let us start with the basics first; refresh the knowledge about TN and LCD displays in general, later we will talk about TFTs (Thin Film Transistors), how they differ from regular monochrome LCD displays. Then we will go on to the ghosting effect, so we will not only discuss the technology behind the construction of the TFT, but also some phenomena, like the ghosting effect, or grayscale inversion, that are important to understand when using an LCD TFT display.

Next, we will look at different technologies of the TFT LCD displays like TN, IPS, VA, and of course about transmissive and transflective LCD displays, because TFT displays also can be transmissive and transflective. In the last part we will talk about backlight.

Let us start with a short review of the most basic liquid crystal cell, which is the TN (twisted nematic) display. On the picture above, we can see that the light can be transmit through the cell or blocked by the liquid crystal cell using voltage. If you want to learn more about monochrome LCD displays and the basics of LCD displays, follow this link.

What is a TFT LCD display and how it is different from a monochrome LCD display? TFT is called an active display. Active, means we have one or more transistors in every cell, in every pixel and in every subpixel. TFT stands for Thin Film Transistor, transistors that are very small and very thin and are built into the pixel, so they are not somewhere outside in a controller, but they are in the pixel itself. For example, in a 55-inch TV set, the TFT display contains millions of transistors in the pixels. We do not see them, because they are very small and hidden, if we zoom in, however, we can see them in every corner of each pixel, like on the picture below.

On the picture above we can see subpixels, that are basic RGB (Red, Green, Blue) colors and a black part, with the transistors and electronic circuits. We just need to know that we have pixels, and subpixels, and each subpixel has transistors. This makes the display active, and thus is called  the TFT display. TFT displays are usually color displays, but there are also monochrome TFT displays, that are active, and have transistors, but have no colors. The colors in the TFT LCD display are typically added by color filters on each subpixel. Usually the filters are RGB, but we also have RGBW (Red, Green, Blue, White) LCD displays with added subpixels without the filter (White) to make the display brighter.

Going a little bit deeper, into the TFT cell, there is a part inside well known to us from the monochrome LCD display Riverdi University lecture. We have a cell, liquid crystal, polarizers, an ITO (Indium Tin Oxide) layer for the electrodes, and additionally an electronic circuit. Usually, the electronic circuit consists of one transistor and some capacitors to sustain the pixel state when we switch the pixel OFF and ON. In a TFT LCD display the pixels are much more complicated because apart from building the liquid crystal part, we also need to build an electronic part.

That is why TFT LCD display technologies are very expensive to manufacture. If you are familiar with electronics, you know that the transistor is a kind of switch, and it allows us to switch the pixel ON and OFF. Because it is built into the pixel itself, it can be done very quickly and be very well controlled. We can control the exact state of every pixel not only the ON and OFF states, but also all the states in between. We can switch the light of the cells ON and OFF in several steps. Usually for TFT LCD displays it will be 8-bit steps per color, so we have 256 steps of brightness for every color, and every subpixel. Because we have three subpixels, we have a 24-bit color range, that means over 16 million combinations, we can, at least theoretically, show on our TFT LCD display over 16 million distinct colors using RGB pixels.

Now that we know how the TFT LCD display works, we can now learn some practical things one of which is LCD TFT ghosting. We know how the image is created, but what happens when we have the image on the screen for a prolonged time, and how to prevent it. In LCD displays we have something called LCD ghosting. We do not see it very often, but in some displays this phenomenon still exists.

You may have seen this phenomenon already as it is common in every display technology, and even companies like Apple put information on their websites, that users may encounter this phenomenon and how to fix it. It is called image ghosting or image persistence, and even Retina displays are not free of it.

Another issue present in TFT displays, especially TN LCD displays, is grayscale inversion. This is a phenomenon that changes the colors of the screen according to the viewing angle, and it is only one-sided. When buying a TFT LCD display, first we need to check what kind of technology it is. If it is an IPS display, like the Riverdi IPS display line, then we do not need to worry about the grayscale inversion because all the viewing angles will be the same and all of them will be very high, like 80, 85, or 89 degrees. But if you buy a more common or older display technology type, like the TN (twisted nematic) display, you need to think where it will be used, because one viewing angle will be out. It may be sometimes confusing, and you need to be careful as most factories define viewing direction of the screen and mistake this with the greyscale inversion side.

On the picture above, you can see further explanation of the grayscale inversion from Wikipedia. It says that some early panels and also nowadays TN displays, have grayscale inversion not necessary up-down, but it can be any angle, you need to check in the datasheet. The reason technologies like IPS (In-Plane Switching), used in the latest Riverdi displays, or VA, were developed, was to avoid this phenomenon. Also, we do not want to brag, but the Wikipedia definition references our website.

We know already that TN (twisted nematic) displays, suffer from grayscale inversion, which means the display has one viewing side, where the image color suddenly changes. It is tricky, and you need to be careful. On the picture above there is a part of the LCD TFT specification of a TN (twisted nematic) display, that has grayscale inversion, and if we go to this table, we can see the viewing angles. They are defined at 70, 70, 60 and 70 degrees, that is the maximum viewing angle, at which the user can see the image. Normally we may think that 70 degrees is better, so we will choose left and right side to be 70 degrees, and then up and down, and if we do not know the grayscale inversion phenomena, we may put our user on the bottom side which is also 70 degrees. The viewing direction will be then like a 6 o’clock direction, so we call it a 6 o’clock display. But you need to be careful! Looking at the specification, we can see that this display was defined as a 12 o’clock display, so it is best for it to be seen from a 12 o’clock direction. But we can find that the 12 o’clock has a lower viewing angle – 60 degrees. What does it mean? It means that on this side there will be no grayscale inversion. If we go to 40, 50, 60 degrees and even a little bit more, probably we will still see the image properly. Maybe with lower contrast, but the colors will not change. If we go from the bottom, from a 6 o’clock direction where we have the grayscale inversion, after 70 degrees or lower we will see a sudden color change, and of course this is something we want to avoid.

To summarize, when you buy older technology like TN and displays, which are still very popular, and Riverdi is selling them as well, you need to be careful where you put your display. If it is a handheld device, you will see the display from the bottom, but if you put it on a wall, you will see the display from the top, so you need to define it during the design phase, because later it is usually impossible or expensive to change the direction.

We will talk now about the other TFT technologies, that allow us to have wider viewing angles and more vivid colors. The most basic technology for monochrome and TFT LCD displays is twisted nematic (TN). As we already know, this kind of displays have a problem with grayscale inversion. On one side we have a higher retardation and will not get a clear image. That is why we have other technologies like VA (Vertical Alignment), where the liquid crystal is differently organized, and another variation of the TFT technology – IPS which is In-Plane Switching. The VA and IPS LCD displays do not have a problem with the viewing angles, you can see a clear image from all sides.

Apart from the different organization of the liquid crystals, we also organize subpixels a little bit differently in a VA and IPS LCD displays. When we look closer at the TN display, we will just see the subpixels with color filters. If we look at the VA or IPS display they will have subpixels of subpixels. The subpixels are divided into smaller parts. In this way we can achieve even wider viewing angles and better colors for the user, but of course, it is more complicated and more expensive to do.

The picture above presents the TN display and grayscale inversion. For IPS or VA technology there is no such effect. The picture will be the same from all the sides we look so these technologies are popular where we need wide viewing angles, and TN is popular where we don’t need that, like in monitors. Other advantages of IPS LCD displays are they give accurate colors, and wide viewing angles. What is also important in practice, in our projects, is that the IPS LCD displays are less susceptible to mechanical force. When we apply mechanical force to the screen, and have an optically bonded touch screen, we push the display as well as squeeze the cells. When we have a TN display, every push on the cell changes the image suddenly, with the IPS LCD displays with in-plane switching, different liquid crystals organization, this effect is lesser. It is not completely removed but it is much less distinct. That is another reason IPS displays are very popular for smartphones, tablets, when we have the touchscreens usually optically bonded.

If we wanted to talk about disadvantages, there is a question mark over it, as some of them may be true, some of them do not rely on real cases, what kind of display, what kind of technology is it. Sometimes the IPS displays can have higher power consumption than others, in many cases however, not. They can be more expensive, but not necessarily. The new IPS panels can cost like TN panels, but IPS panels definitely have a longer response time. Again, it is not a rule, you can make IPS panels that are very fast, faster than TN panels, but if you want the fastest possible display, probably the TN panel will be the fastest. That is why the TN technology is still popular on the gaming market. Of course, you can find a lot of discussions on the internet, which technology is better, but it really depends on what you want to achieve.

Now, let us look at the backlight types. As we see here, on the picture above, we have four distinct types of backlight possible. The most common, 95 or 99 per cent of the TFT LCD displays on the market are the transmissive LCD display type, where we need the backlight from the back. If you remember from our Monochrome LCD Displays lecture, for transmissive LCD displays you need the backlight to be always on. If you switch the backlight off, you will not see anything. The same as for monochrome LCD displays, but less popular for TFT displays, we have the transflective LCD display type. They are not popular because usually for transflective TFT displays, the colors lack in brightness, and the displays are not very practical to use. You can see the screen, but the application is limited. Some transflective LCD displays are used by military, in applications where power consumption is paramount; where you can switch the backlight off and you agree to have lower image quality but still see the image. Power consumption and saving energy is most important in some kind of applications and you can use transflective LCD displays there. The reflective type of LCD displays are almost never used in TFT. There is one technology called Low Power Reflective Displays (LPRD) that is used in TFT but it is not popular. Lastly, we have a variation of reflective displays with frontlight, where we add frontlight to the reflective display and have the image even without external light.

Just a few words about Low Power Reflective Displays (LPRD). This kind of display uses environmental light, ambient light to reflect, and produce some colors. The colors are not perfect, not perfectly clear, but this technology is becoming increasingly popular because it allows to have color displays in battery powered applications. For example, a smartwatch would be a case for that technology, or an electrical bike or scooter, where we can not only have a standard monochrome LCD display but also a TFT LCD color display without the backlight; we can see the image even in

strong sunlight and not need backlight at all. So, this kind of TFL LCD display technology is getting more and more popular when we have outdoor LCD displays and need a low power consumption.

On the picture above, we have some examples of how transmissive and reflective LCD displays work in the sunlight. If we have a simple image, like a black and white pattern, then on a transmissive LCD display, even with 1000 candela brightness, the image probably will be lower quality than for a reflective LCD display; if we have sunlight, we have very strong light reflections on the surface of the screen. We have talked about contrast in more detail in the lecture Sunlight Readable Displays. So, reflective LCD displays are a better solution for outdoor applications than transmissive LCD displays, where you need a really strong backlight, 1000 candela or more, to be really seen outdoors.

To show you how the backlight of LCD displays is built, we took the picture above. You can see the edge backlight there, where we have LEDs here on the small PCB on the edge, and we have a diffuser that distributes the light to the whole surface of LCD screen.

In addition to the backlight, we have something that is called a frontlight. It is similar to backlight, it also uses the LEDs to put the light into it, but the frontlight needs to be transparent as we have the display behind. On the example on the picture above we can see an e-paper display. The e-paper display is also a TFT display variation, but it is not LCD (liquid crystal), it is a different technology, but the back of the display is the same and it is reflective. The example you see is the Kindle 4 eBook reader. It uses an e-paper display and a frontlight as well, so you can read eBooks even during the night.

This new range of TFT LCD displays with unique characteristics come with the standard interfaces including MiPi, SPI, RGB, DisplayPort and eDP. However, to aid our customers and increase our flexibility of interfacing we are also offering proprietary interface boards which allow you to simply interface via the HDMI / USBC inputs. If you would like more information on this interface board, then please just contact us.

Another major development, available on most of the new range, is the full active LED dimming backlighting which is a technology improvement on edge lit displays. This new technology allows you to control certain parts of the screen and to optimize colours and shades.

On one side, it pushes the video to the LCD layer but on the other side, it processes the video, decides what the best brightness should be for each and every section of the LCD (divided into zones) based upon the image that is on it. Then it tells each LED what brightness to be for optimisation. The result is that the blacks are darker, the whites are brighter, and everything in between is more in tune with what they should be. And this is happening 60 times per second, wow, what a performance for optimization process!

You can achieve true HDR (High-dynamic-range) and can exceed HDR1000* specs.  The dynamic contrast ratio is virtually unlimited and as you can see can reach 10 Million to one (10M:1) and you can achieve peak brightness that’s daylight readable but have the colour and brightness depth of an OLED display.  We are seeing great interest in these displays in areas such as broadcast, medical and automotive industries as they value the quality of the image and performance that standard TFTs cannot offer.