transmissive tft lcd display free sample

Focus Displays offers a wide range of standard full color TFT displays. 64 million unique colors, high brightness, sharp contrast, -30C operating temperature, and fast response time are all good descriptions of a TFT display. This is why TFT technology is one of the most popular choices for a new product.

Thin Film Transistor (TFT) display technology can be seen in products such as laptop computers, cell phones, tablets, digital cameras, and many other products that require color. TFT’s are active matrix displays which offers exceptional viewing experiences especially when compared to other passive matrix technologies. The clarity on TFT displays is outstanding; and they possess a longer half-life than some types of OLEDs and range in sizes from less than an inch to over 15 inches.

CCFL’s are still available, but are becoming a legacy (obsolete) component. TFT displays equipped with a CCFL require higher MOQs (Minimum Order Quantities) than displays with LED backlights.

The majority of TFT displays contain a touch panel, or touch screen. The touch panel is a touch-sensitive transparent overlay mounted on the front of the display glass. Allowing for interaction between the user and the LCD display.

Some touch panels require an independent driver IC; which can be included in the TFT display module or placed on the customer’s Printed Circuit Board (PCB). Touch screens make use of coordinate systems to locate where the user touched the screen.

Resistive touch panels are the lowest cost option and are standard equipment on many TFT modules. They are more common on smaller TFT displays, but can still be incorporated on larger modules.

Contrast ratio, or static contrast ratio, is one way to measure the sharpness of the TFT LCD display. This ratio is the difference between the darkest black and the brightest white the display is able to produce. The higher the number on the left, the sharper the image. A typical contrast ratio for TFT may be 300:1. This number ratio means that the white is 300 times brighter than the black.

TFT LCD displays are measured in inches; this is the measurement of the diagonal distance across the glass. Common TFT sizes include: 1.77”, 2.4”, 2.8”, 3”, 4.3”, 5”, 5.7”, 5.8”, 7”, 10.2”, 12.1 and 15”.

As a general rule, the larger the size of the glass the higher the cost of the display, but there are exceptions to this rule. A larger display may be less expensive than a smaller display if the manufacture produces higher quantities of the larger displays. When selecting your color display, be sure to ask what the cost is for one size smaller and one size larger. It may be worth modifying your design requirements.

TFT resolution is the number of dots or pixels the display contains. It is measured by the number of dots along the horizontal (X axis) and the dots along the vertical (Y axis).

The higher the resolution, the more dots per square inch (DPI), the sharper the display will look. A higher resolution results in a higher cost. One reason for the increase in cost is that more driver chips are necessary to drive each segment.

Certain combinations of width and height are standardized and typically given a name and a letter representation that is descriptive of its dimensions. Popular names given to the TFT LCD displays resolution include:

Transmissive displays must have the backlight on at all times to read the display, but are not the best option in direct sunlight unless the backlight is 750 Nits or higher. A majority of TFT displays are Transmissive, but they will require more power to operate with a brighter backlight.

Transflective displays are readable with the backlight off provided there is enough ambient light. Transflective displays are more expensive than Transmissive also there may be a larger MOQ for Transflective. However, Transflective displays are the best option for direct sunlight.

Drivers update and refresh the pixels (Picture Elements) of a display. Each driver is assigned a set number of pixels. If there are more pixels than a single driver can handle, then an additional drivers are added.

A primary job of the driver is to refresh each pixel. In passive TFT displays, the pixel is refreshed and then allowed to slowly fade (aka decay) until refreshed again. The higher the refresh frequency, the sharper the displays contrast.

The controller does just what its name suggest. It controls the drivers. There is only one controller per display no matter how many drivers. A complex graphic display with several thousand pixels will contain one controller and several drivers.

The TFT display (minus touch screen/backlight) alone will contain one controller/driver combination. These are built into the display so the design engineer does not need to locate the correct hardware.

If you do not see a Thin Film Transistor (TFT) Display module that meets your specifications, or you need a replacement TFT, we can build a custom TFT displays to meet your requirements. Custom TFTs require a one-time tooling fee and may require higher MOQs.

Ready to order samples for your TFT design? Contact one of our US-based technical support people today concerning your design requirements. Note: We can provide smaller quantities for samples and prototyping.

The Transmissive polarizer is best used for displays that run with the backlight on all the time. This polarizer provides the brightest backlight possible. If you have a need for a bright backlight with lower power drain, transmissive is a good choice for this TFT LCD display.

Focus LCDs can provide many accessories to go with your display. If you would like to source a connector, cable, test jig or other accessory preassembled to your LCD (or just included in the package), our team will make sure you get the items you need.Get in touch with a team member today to accessorize your display!

Focus Display Solutions (aka: Focus LCDs) offers the original purchaser who has purchased a product from the FocusLCDs.com a limited warranty that the product (including accessories in the product"s package) will be free from defects in material or workmanship.

1.What kinds of display does HEM have? HEM is specializing in manufacturing TFT LCD display, Monochrome LCD display,Touch Screen, customized LCD panel, COB and COG display. 2.How can I find the right product? Please send us your requirements or datasheet, we will recommend our standard products, if it’s not fit, we will do the necessary adjustment & customization. 3. Do you accept sample order or small quantity order? Yes, you can place sample orders for testing first, and small quantity order as pilot production (no less than MOQ) 4.What’s the lead time? Usually 3~5 days for sample orders if goods are in stock, and 4~5 weeks for mass production (basing on the quantity and particular product). 5.What’s your order process? evaluating the project and give quotation→confirming with the customers→customers 100% pay the tooling fee and samples cost in advance→we arrange the drawings for customer in three woking days after received the payment→customers confirm the drawings→we arrange the production of samples in two or three weeks after the customers confirm the drawings are okay→send the sample to the customers for testing→modify the design according to the customer"s opinion and send the sample again until the customer is satisfied→customer 30% payment in advance→batch production

We now have two complete monochrome LCD production lines, a dozen of fully automatic COG production line and the full processing capacity for COB and CTP full lamination.With a professional R&D team, Well-developed quality control system, highly effective execution and management team and a pro-innovation corporate culture. We vow to satisfy our customers by meeting the quantity and quality requirements.

Huaersheng invested 160 mu display industrial park in 2022,which has the floorage of 12000 square matres. Park planning: 2 panel production lines of 370mm*470mm, 6full-automatic AMOLED production lines,30 COG full-automatic AMOLED production lines.

Established in 2010, Topfoison has devoted itself to the manufacturing and development of high-quality products for the Wearable device, Smart Watch, VR, Medical device, Industrial LCD display including Color LCD modules/OLED/LCD display/Round lcd screen/Round AMOLED/ Square transflective lcd screen/ IPS full wide display/ 1080p fhd AMOLED and 2K 1440p lcd. Topfoison focus on1.22-7.0 inch small size displays, all the products produced in our company enjoys the most advanced production craft and technology as well as the strictly ISO quality management system.

Established in 2010, Topfoison has devoted itself to the manufacturing and development of high-quality products for the Wearable device, Smart Watch, VR, Medical device, Industrial LCD display including Color LCD modules/OLED/LCD display/Round lcd screen/Round AMOLED/ Square transflective lcd screen/ IPS full wide display/ 1080p fhd AMOLED and 2K 1440p lcd. Topfoison focus on1.22-7.0 inch small size displays, all the products produced in our company enjoys the most advanced production craft and technology as well as the strictly ISO quality management system.

We have over two dozen TFT LCD display modules to choose from. All of them are full-color graphic displays. Unlike standard monochrome character displays, you can create complex images for imaginative user experiences. Thin and light, these are ideal for handheld devices, communications equipment, information displays, and test and measurement equipment.

Listed by the diagonal size of the active area (the usable area for lit pixels), our TFT display sizes range from 1.3 inches to 10.1 inches. Choose from six different interfaces, many of our TFT modules have more than one interface available. Arduino users should select modules with SPI for fast and easy communications to add color graphics to their projects.

Contrast ratio is the difference between a pixel that is lit or dark. Standard STN LCD displays typically have a 10:1 contrast ratio while TFT displays are 300:1 and up, so details stand out and text looks extra sharp. For standard STN displays, you must choose a display limited to a specific viewing angle (12, 3, 6 or 9 o"clock) while TFTs can have a viewing cone greater than 160 degrees.

To speed up your design time, we sell carrier boards and demonstration kits for selected modules. For outdoor use, be sure to look at our sunlight readable displays.

Different displays have different characteristics, just tell Panox Display your application, and operating environment, Panox Display will suggest a suitable display for you.

But Panox Display is not a school, if customers don`t know the basic knowledge to design circuit boards, we suggest using our controller board to drive the display.

First, you need to check whether this display has On-cell or In-cell touch panel, if has, it only needs to add a cover glass on it. If not, it needs an external touch panel.

If you don`t know or don`t want to write a display program on Raspberry Pi, it`s better to get an HDMI controller board from us, and Panox Display will send a config.txt file for reference.

When display devices are brought outside, oftentimes they face the brightness of sunlight or any other form of high ambient light sources reflecting off of and overwhelming the LED backlight’s image.

With the growth of the LCD panel industry as a whole, it has become more important than ever to prevent the sun’s wash out of displays used outdoors, such as automobile displays, digital signage, and public kiosks. Hence, the sunlight readable display was invented.

One solution would be to increase the luminance of the TFT LCD monitor’s LED backlight to overpower the bright sunlight and eliminate glare. On average, TFT LCD screens have a brightness of about 250 to 450 Nits, but when this is increased to about 800 to 1000 (1000 is the most common) Nits, the device becomes a high bright LCDand a sunlight readable display.

Since many of today’s TFT LCD display devices have shifted to touchscreens, the touch panels on the surface of LCD screens already block a small percentage of backlighting, decreasing the surface brightness and making it so that the sunlight can even more easily wash out the display. Resistive touch panels use two transparent layers above the glass substrate, but the transparent layers can still block up to 5% of the light.

In order to optimize the high brightness of the backlight, a different type of touchscreen can be used: the capacitive touchscreen. Though it is more expensive than the resistive touch screen, this technology is more ideal for sunlight readable displays than the resistive due to its usage of a thinner film or even in-cell technologies rather than two layers above the glass of the display, and therefore, light can pass more efficiently.

However, with this method comes a list of potential problems. Firstly, high brightness displays result in much greater power consumption and shorter battery life. In order to shed more light, more power will be needed which can also consequently result in device overheating which can also shorten battery life. If the backlight’s power is increased, the LED’s half-life may also be reduced.

While in bright exterior light settings, these devices reduce eye strain as the user attempts to view the image on screen, the brightness of the display itself can also cause eye strain, seen as the brightness may overwhelm your eyes. Many devices allow the user to adjust brightness, so this concern is oftentimes not too severe.

A recent technology falling into the sunlight readable display category is the transflective TFT LCD, coming from a combination of the word transmissive and reflective. By using a transflective polarizer, a significant percentage of sunlight is reflected away from the screen to aid in the reduction of wash out. This optical layer is known as the transflector.

In transflective TFT LCDs, sunlight can reflect off the display but can also pass through the TFT cell layer and be reflected back out off a somewhat transparent rear reflector in front of the backlight, illuminating the display without as much demand and power usage from the transmissive nature of the backlight. This addresses both the issues of wash out and the disadvantages of high brightness TFT LCDs in high ambient light environments. Because of its transmissive and reflective modes, this type of device is very useful for devices that will be used outdoors but also indoors.

While it does greatly reduce power consumption, transflective LCDs are much more expensive than high brightness LCDs. In recent years, the cost has decreased, but transflective LCDs continue to be more costly.

In addition to adjustments to the internal mechanics of LCDs, it is possible to make devices more sunlight-readable using surface treatments. The most common are anti-reflective (A/R) films/coatings and anti-glare processing.

When anti-glare is used, reflected light is fragmented. Using a rough surface as opposed to a smooth one, anti-glare treatments can reduce the reflection’s disruption of the actual image of the display.

Often paired with other methods of creating sunlight readable displays is optical bonding. By gluing the glass of a display to the TFT LCD cells beneath it, optical bonding eliminates the air gap that traditional LCD displays have in them using an optical grade adhesive.

This adhesive reduces the amount of reflection between the glass and LCD cell as well as the reflection of external ambient light. Doing this helps provide a clearer image with an increased contrast ratio, or the difference in the light intensity of the brightest white pixel color and darkest black pixel color.

With this contrast ratio improvement, optical bonding addresses the root issue with unreadable outdoor displays: the contrast. Though an increase in brightness can improve contrast, by fixing the contrast itself, LCD display images in outdoor environments will not be as washed out and will require less power consumption.

Besides the visual display advantages that optical bonding provides, this adhesive improves the display in many other ways. The first being durability, optical bonding eliminates the air gap within the device and replaces it with a hardened adhesive that can act as a shock absorber.

Touch screens with optical bonding gain, accuracy in where the point of contact is between the touch and screen. What is known as parallax, the refraction angle of light, can make it seem that the point of contact and the actual point on the display are different. When the adhesive is used, this refraction is minimized, if not reduced.

The optical bonding adhesive’s elimination of the air gap also protects the LCD from moisture/fogging and dust, as there is no space for impurities to penetrate and remain under the glass layer. This especially helps with maintaining the state of LCDs in transport, storage, and humid environments.

Compiling the various methods of improving LCD screens for sunlight readability, these devices can be optimized in high ambient light settings. An anti-glare coating is applied to the surface of the glass and anti-reflective coatings are applied to both the front and back. The transflector is also used in front of the backlight. These features can result in 1000 Nit or more display lighting, without the excessive power consumption and heat production through a high brightness backlight, consequently allowing for a longer lasting and better performing LCD

Unfortunately, the process of building a reflector inside TFT LCD is complicated and transflective TFT LCD is normally several times higher cost compared with normal transmissive TFT LCD.

To further improve and enhance the qualities of the LCD, LED and cold cathode fluorescent lamp (CCFL) backlights are used. Both these create bright displays, but the LED specifically can do so without as much power consumption and heat generation as compared to the CCFL option. Optical bonding is also applied in order to improve display contrast, leading to a more efficient and better quality sunlight readable display.

In this guide, you’ll learn how to locate example code and upload it to your microcontroller for prototyping with your display. This article is meant to be used as a tutorial using our

Support Center to locate hundreds of free example code written by our engineers, designed specifically for our displays. These resources are organized by display type, but feel free to use the search bar to locate a specific part number that you are looking for code on. Here"s a quick step-by-step guide to reference:

displays. You’ll find a wide variety of example codes here available for free. Using these codes will help you see the different features and functions our displays are capable of.

1. In the "find a repository" search bar, enter the display part number to see available code. You"ll see results start to populate as you type. The part number for our 4x20 slim character OLED is "0420cw"

This module is a color active matrix TFT-LCD (Thin Film Transistor Liquid Crystal Display) module that uses amorphous silicon TFT as a switching device. This module is composed of LCD panel, driver IC, and LED backlight, with a Capacitive Touch Panel.

Shenzhen SLS Industrial Co.,ltd established in 2003, is a professional LCD module manufacturer and solution provider. We have 1 full-auto COG assembly line, 2 semi-auto assembly line, backlight assembly line, no dust TP bonding line and manufacturing tech support, we can provide unique, innovative and cost effective LCD module development and manufacturing. Our product range includes: middle-small size TFT LCD, industrial capacitive touch panel... Our LCD products have been widely used in communications, GPS, Equipment, electronic audio-visual, instrumentation, household appliances, PDA and other industries.

Hot Tags: 3.9 Inch ST7282 480x128 Dots Transmissive With Capacitive Touch Panel Tft Lcd Module, China, suppliers, factory, wholesale, price list, free sample

Transmissive LCD is the most common LCD screen, which requires a backlight as the light source and there is no reflective film at the back of the LCD screen.

Advantage: we can see the graphic and character on the screen very clearly if there is only little light. It is such a mature and cheap technology that 90% of LCD screens in the market are transmissive LCD display.

Reflective LCD is the cheapest LCD screen because there is no backlight, which uses light from outside as the light source, such as sunshine or lamplight and there is a reflective film at the back of the LCD screen.

Transflective LCD is the best and most expensive LCD screen, which has a semi-reflective film at the back of the LCD screen. The front light can’t go through the semi-reflective film, but the backlight can go through it. Like sunglasses.

Advantage: it has the advantages of both transmissive LCD and reflective LCD. We not only can see it very clearly in the outdoor like the reflective LCD, but also can see it vividly when we are in a dark place like a transmissive LCD. We see the transflective LCD in the front as the reflective LCD because it can reflect the sunshine, but the LED backlight panel can also supply the light which can penetrate the semi-reflective film at the back of LCD screen.

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.

If some elements of the picture i.e., your company logo is in the same place of the screen for a long period of time, for couple of weeks, months or a year, the crystals will memorize the state and later, when we change the image, we may see some ghosting of those elements. It really depends on many conditions like temperature and even the screen image that we display on the screen for longer periods of time. When you build your application, you can use some techniques to avoid it, like very rapid contrast change and of course to avoid the positioning the same image in the same position for a longer time.

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.