tft display vs led backlit factory

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.

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.

Confused about LED vs. LCD vs. TFT? Here"s everything you need to know. Creating or upgrading a device display or screen can involve a lot of different things, but it often comes down to one major question - what kind of display should you get?

So, there are 3 common displays LED, LCD and TFT available in the market. All terms refer to the flat-panel display, or screen, of a computer monitor or television set. In this article, we are going to differentiate between them. It will help you to choose a better one.

LCD stands for liquid crystal display. Works by adjusting the amount of light blocked. Usually has a backlight but might not (clocks, calculators, Nintendo Gameboy). The green-black ones can be very cheap and are a mature technology. Response time can be slow. An LCD display uses the light balancing qualities of crystals. Today LCDs are used in a great number of products and applications. Your TV, computer screen, calculator, cell phone and the dreaded alarm clock are all made of an LCD flat panel. Color LCDs produce the color based on two techniques: Passive matrix and active matrix. Passive matrix is the cheapest technology of the two. The other technology is called an active matrix or TFT. Active matrix displays produce really sharp and clear images.

This is a type of LCD with a thin film transistor attached to each pixel. All computer LCD screens are TFT since the early 2000s; older ones had slower response times and poorer color. Cost is now very good; power consumption is fairly good but dominated by the backlight. Has to be manufactured out of glass. The TFT layer is embedded in the screen itself, it reduces crosstalk between pixels. Crosstalk happens when a signal sends to a pixel also affects the pixel next to it. This makes the TFT technology the technology offering the best resolution and image quality. It also makes it a bit more expensive. Today TFTs have become the standard when producing LCD screens.

LED stands for a light emitting diode. As the name suggests, emits light rather than blocking it like LCD. Used for red/green/blue/white indicator lights everywhere. Some manufacturers advertise "LED" displays that are TFT screens with a white LED backlight, which is just confusing. Ones that are real LED screens are usually OLED.

Some devices actually have backlights made from Red, Green and Blue LEDs, normally referred to as RGB LED, which tend to have better color reproduction than any other display.

LED screen is just like saying that it is a plastic screen. You still have the WHOLE screen illuminated all the time and LED is "good" only for being more eco-friendly and probably more bright at max setting if you ever need this.

An LCD panel is, in fact, 2 layers of glass with some volume of Liquid Crystal in between. These two form the panel itself. The 2 layers are usually called Color Filter Glass (above) and TFT glass (below).

A standard TFT has a whole "lamp" behind it, illuminating the whole screen all the time. This way, you cannot have a true black, as it is still illuminated and stay grayish.

TFTs are a type of active matrix display that controls individual pixel updates several times per second on the screen to update the image relative to the content source.

TFT displays use more electricity than regular LCD screens, so they not only cost more in the first place, but they are also more expensive to operate.

LCDs use fluorescent lights while LEDs use those light emitting diodes. The fluorescent lights in an LCD are always behind the screen. On an LED, the light emitting diodes can be placed either behind the screen or around its edges.

Important technical improvements of LCD, such as LED backlighting and wide viewing Angle, are directly related to LCD. And account for an LCD display 80% of the cost of the LCD panel, enough to show that the LCD panel is the core part of the entire display, the quality of the LCD panel, can be said to directly determine the quality of an LCD display.

The production of civil LCD displays is just an assembly process. The LCD panel, the main control circuit, shell, and other parts of the main assembly, basically will not have too complex technical problems.

Due to the LCD does not shine, so you need to use another light source to illuminate, the function of the backlight system is to this, but currently used CCFL lamp or LED backlight, don’t have the characteristics of the surface light source, so you need to guide plate, spreadsheet components, such as linear or point sources of light evenly across the surface, in order to make the entire LCD panel on the differences of luminous intensity is the same, but it is very difficult, to achieve the ideal state can be to try to reduce brightness non-uniformity, the backlight system has a lot to the test of design and workmanship.

In addition, there is a driving IC and printed circuit board beside the LCD panel, which is mainly used to control the rotation of LCD molecules in the LCD panel and the transmission of display signals. The LCD plate is thin and translucent without electricity. It is roughly shaped like a sandwich, with an LCD sandwiched between a layer of TFT glass and a layer of colored filters.

First of all, the motion and arrangement of LCD molecules need electrons to drive them. Therefore, on the TFT glass, the carrier of LCD, there must be conductive parts to control the motion of LCD. In this case, we use ITO (Indium Tin Oxide) to do this.ITO is transparent and also acts as a thin-film conductive crystal so that it doesn’t block the backlight.

The different arrangement of LCD molecules and the rapid motion change can ensure that each pixel displays the corresponding color accurately and the image changes accurately and quickly, which requires the precision of LCD molecule control.ITO film needs special treatment, just like printing the circuit on the PCB board, drawing the conductive circuit on the whole LCD board.

First, the ITO film layer needs to be deposited on the TFT glass, so that there is a smooth and uniform ITO film on the whole TFT glass. Then, using ionized water, the ITO glass is cleaned and ready for the next step.

This completes the previous Array process. It is not difficult to see from the whole process that ITO film is deposited, photoresist coated, exposed, developed, and etched on TFT glass, and finally, ITO electrode pattern designed in the early stage is formed on TFT glass to control the movement of LCD molecules on the glass. The general steps of the whole production process are not complicated, but the technical details and precautions are very complicated, so we will not introduce them here. Interested friends can consult relevant materials by themselves.

The glass that the LCD board uses makes a craft also very exquisite. (The manufacturing process flow of the LCD display screen)At present, the world’s largest LCD panel glass, mainly by the United States Corning, Japan Asahi glass manufacturers, located in the upstream of the production of LCD panel, these manufacturers have mastered the glass production technology patents. A few months ago, the earthquake caused a corning glass furnace shutdown incident, which has caused a certain impact on the LCD panel industry, you can see its position in the industry.

As mentioned earlier, the LCD panel is structured like a sandwich, with an LCD sandwiched between the lower TFT glass and the upper color filter. The terminal Cell process in LCD panel manufacturing involves the TFT glass being glued to the top and bottom of a colored filter, but this is not a simple bonding process that requires a lot of technical detail.

After the TFT glass substrate is cleaned, a sealant coating is applied to allow the TFT glass substrate to be bonded to the color filter and to prevent LCD outflow.

Finally, the conductive adhesive is applied to the frame in the bonding direction of the glass of the color filter to ensure that external electrons can flow into the LCD layer. Then, according to the bonding mark on the TFT glass substrate and the color filter, two pieces of glass are bonded together, and the bonding material is solidified at high temperatures to make the upper and lower glasses fit statically.

When making LCD panel, must up and down each use one, and presents the alternating direction, when has the electric field and does not have the electric field, causes the light to produce the phase difference and to present the light and dark state, uses in the display subtitle or the pattern.

The rear Module manufacturing process is mainly the integration of the drive IC pressing of the LCD substrate and the printed circuit board. This part can transmit the display signal received from the main control circuit to the drive IC to drive the LCD molecules to rotate and display the image. In addition, the backlight part will be integrated with the LCD substrate at this stage, and the complete LCD panel is completed.

Next is the drive IC press. The main function of the drive IC is to output the required voltage to each pixel and control the degree of torsion of the LCD molecules. The drive IC is divided into two types. The source drive IC located in the X-axis is responsible for the input of data. It is characterized by high frequency and has an image function. The gate drive IC located in the Y-axis is responsible for the degree and speed of torsion of LCD molecules, which directly affects the response time of the LCD display. However, there are already many LCD panels that only have driving IC in the X-axis direction, perhaps because the Y-axis drive IC function has been integrated and simplified.

LCD (LC) is a kind of LCD, which has the properties of light transmission and refraction of solid Crystal, as well as the flow property of Liquid. It is because of this property that it will be applied to the display field.

However, LCD does not emit light autonomously, so the display equipment using LCD as the display medium needs to be equipped with another backlight system.

First, a backplate is needed as the carrier of the light source. The common light source for LCD display equipment is CCFL cold cathode backlight, but it has started to switch to an LED backlight, but either one needs a backplate as the carrier.

CCFL backlight has been with LCD for a long time. Compared with LED backlight, CCFL backlight has many defects. However, it has gradually evolved to save 50% of the lamp and enhance the transmittance of the LCD panel, so as to achieve the purpose of energy-saving.

With the rapid development of LED in the field of lighting, the cost has been greatly reduced.LCD panels have also started to use LED as the backlight on a large scale. Currently, in order to control costs, an LED backlight is placed on the side rather than on the backplate, which can reduce the number of LED grains.

However, no matter CCFL backlight or LED backlight is placed in various ways, the nature of the backlight source cannot be a surface light source, but a linear light source or point light source. Therefore, other components are needed to evenly distribute the light to the whole surface. This task is accomplished by the diffuser plate and diffuser plate.

On the transparent diffuser plate, point-like printing can block part of the light. The LED backlight on the side drives the light from the side of the diffuser plate, and the light reflects and refracts back and forth in the diffuser plate, distributing the light evenly to the whole surface. Point-like printing blocks part of the light, screening the light evenly like a sieve.

At the top of the diffusion plate, there will be 3~4 diffuser pieces, constantly uniform light to the whole surface, improve the uniformity of light, which is directly related to the LCD panel display effect. Professional LCD in order to better control the brightness uniformity of the screen, panel procurement, the later backlight control circuit, will make great efforts to ensure the quality of the panel.

However, it is much simpler to use a side white LED as a backlight. The small circuit board on the far left of the figure above is the backlight of the LED.

This is the general structure of the backlight system. Since I have never seen the backlight mode of R.G.B LED, I cannot tell you what the backlight mode is like. I will share it with you when I see it in the future.

Before you get a new monition for your organization, comparing the TFT display vs IPS display is something that you should do. You would want to buy the monitor which is the most advanced in technology. Therefore, understanding which technology is good for your organization is a must. click to view the 7 Best Types Of Display Screens Technology.

That is why it is important to break it down and discuss point by point so that you can understand it in a layman’s language devoid of any technical jargon. Therefore, in this very article, let’s discuss what exactly TFT LCDs and IPS LCDs are, and what are their differences? You will also find out about their pros and cons for your organization.

The word TFT means Thin-Film-Translator. It is the technology that is used in LCD or Liquid Crystal Display. Here you should know that this type of LCD is also categorically referred to as active-matrix LCDs. It tells that these LCDs can hold back some pixels while using other pixels. So, the LCD will be using a very minimum amount of energy to function. TFT LCDs have capacitors and transistors. These are the two elements that play a key part in ensuring that the display monitor functions by using a very small amount of energy without running out of operation.

Now, it is time to take a look at its features that are tailored to improve the experience of the monitor users significantly. Here are some of the features of the TFT monitor;

The display range covers the application range of all displays from 1 inch to 40 inches as well as the large projection plane and is a full-size display terminal.

Display quality from the simplest monochrome character graphics to high resolution, high color fidelity, high brightness, high contrast, the high response speed of a variety of specifications of the video display models.

No radiation, no scintillation, no harm to the user’s health. In particular, the emergence of TFT LCD electronic books and periodicals will bring humans into the era of a paperless office and paperless printing, triggering a revolution in the civilized way of human learning, dissemination, and recording.

It can be normally used in the temperature range from -20℃ to +50℃, and the temperature-hardened TFT LCD can operate at low temperatures up to -80 ℃. It can not only be used as a mobile terminal display, or desktop terminal display but also can be used as a large screen projection TV, which is a full-size video display terminal with excellent performance.

The manufacturing technology has a high degree of automation and good characteristics of large-scale industrial production. TFT LCD industry technology is mature, a mass production rate of more than 90%.

TFT LCD screen from the beginning of the use of flat glass plate, its display effect is flat right angles, let a person have a refreshing feeling. And LCDs are easier to achieve high resolution on small screens.

The word IPS refers to In-Plane-Switching which is a technology used to improve the viewing experience of the usual TFT displays. You can say that the IPS display is a more advanced version of the traditional TFT LCD module. However, the features of IPS displays are much more advanced and their applications are very much widespread. You should also know that the basic structure of the IPS LCD is the same as TFT LCD if you compare TFT LCD vs IPS.

As you already know, TFT displays do have a very quick response time which is a plus point for it. But, that does not mean IPS displays a lack of response time. In fact, the response time of an IPS LCD is much more consistent, stable, and quick than the TFT display that everyone used to use in the past. However, you will not be able to gauge the difference apparently by watching TFT and IPS displays separately. But, once you watch the screen side-by-side, the difference will become quite clear to you.

The main drawback of the TFT displays as figured above is the narrow-angle viewing experience. The monitor you buy for your organization should give you an experience of wide-angle viewing. It is very much true if you have to use the screen by staying in motion.

So, as IPS displays are an improved version of TFT displays the viewing angle of IPS LCDs is very much wide. It is a plus point in favor of IPS LCDs when you compare TFT vs IPS. With a TFT screen, you cannot watch an image from various angles without encountering halo effects, blurriness, or grayscale that will cause problems for your viewing.

It is one of the major and remarkable differences between IPS and TFT displays. So, if you don’t want to comprise on the viewing angles and want to have the best experience of viewing the screen from wide angles, the IPS display is what you want. The main reason for such a versatile and wonderful viewing angle of IPS display is the screen configuration which is widely set.

Now, when you want to achieve wide-angle viewing with your display screen, you need to make sure it has a faster level of frequency transmittance. It is where IPS displays overtake TFT displays easily in the comparison because the IPS displays have a much faster and speedier transmittance of frequencies than the TFT displays.

Now the transmittance difference between TFT displays and IPS displays would be around 1ms vs. 25ms. Now, you might think that the difference in milliseconds should not create much of a difference as far as the viewing experience is concerned. Yes, this difference cannot be gauged with a naked eye and you will find it difficult to decipher the difference.

However, when you view and an IPS display from a side-by-side angle and a TFT display from a similar angle, the difference will be quite evident in front of you. That is why those who want to avoid lagging in the screen during information sharing at a high speed; generally go for IPS displays. So, if you are someone who is looking to perform advanced applications on the monitor and want to have a wider viewing angle, then an IPS display is the perfect choice for you.

As you know, the basic structure of the IPS display and TFT displays are the same. So, it is quite obvious that an IPS display would use the same basic colors to create various shades with the pixels. However, there is a big difference with the way a TFT display would produce the colors and shade to an IPS display.

The major difference is in the way pixels get placed and the way they operate with electrodes. If you take the perspective of the TFT display, its pixels function perpendicularly once the pixels get activated with the help of the electrodes. It does help in creating sharp images.

But the images that IPS displays create are much more pristine and original than that of the TFT screen. IPS displays do this by making the pixels function in a parallel way. Because of such placing, the pixels can reflect light in a better way, and because of that, you get a better image within the display.

As the display screen made with IPS technology is mostly wide-set, it ensures that the aspect ratio of the screen would be wider. This ensures better visibility and a more realistic viewing experience with a stable effect.

As you already know the features of both TFT and IPS displays, it would be easier for you to understand the difference between the two screen-types. Now, let’s divide the matters into three sections and try to understand the basic differences so that you understand the two technologies in a compressive way. So, here are the difference between an IPS display and a TFT display;

Now, before starting the comparison, it is quite fair to say that both IPS and TFT displays have a wonderful and clear color display. You just cannot say that any of these two displays lag significantly when it comes to color clarity.

However, when it comes to choosing the better display on the parameter of clarity of color, then it has to be the IPS display. The reason why IPS displays tend to have better clarity of color than TFT displays is a better crystal oriental arrangement which is an important part.

That is why when you compare the IPS LCD with TFT LCD for the clarity of color, IPS LCD will get the nod because of the better and advanced technology and structure.

IPS displays have a wider aspect ratio because of the wide-set configuration. That is why it will give you a better wide-angle view when it comes to comparison between IPS and TFT displays. After a certain angle, with a TFT display, the colors will start to get a bit distorted.

But, this distortion of color is very much limited in an IPS display and you may see it very seldom after a much wider angle than the TFT displays. That is why for wide-angle viewing, TFT displays will be more preferable.

When you are comparing TFT LCD vs. IPS, energy consumption also becomes an important part of that comparison. Now, IPS technology is a much advanced technology than TFT technology. So, it is quite obvious that IPS takes a bit more energy to function than TFT.

Also, when you are using an IPS monitor, the screen will be much larger. So, as there is a need for much more energy for the IPS display to function, the battery of the device will drain faster. Furthermore, IPS panels cost way more than TFT display panels.

1. The best thing about TFT technology is it uses much less energy to function when it is used from a bigger screen. It ensures that the cost of electricity is reduced which is a wonderful plus point.

2. When it comes to visibility, the TFT technology enhances your experience wonderfully. It creates sharp images that will have no problems for older and tired eyes.

1. One of the major problems of TFT technology is that it fails to create a wider angle of view. As a result, after a certain angle, the images in a TFT screen will distort marring the overall experience of the user.

Although IPS screen technology is very good, it is still a technology based on TFT, the essence of the TFT screen. Whatever the strength of the IPS, it is a TFT-based derivative.

Finally, as you now have a proper understanding of the TFT displays vs IPS displays, it is now easier for you when it comes to choose one for your organization. Technology is advancing at a rapid pace. You should not be surprised if you see more advanced display screens in the near future. However, so far, TFT vs IPS are the two technologies that are marching ahead when it comes to making display screens.

STONE provides a full range of 3.5 inches to 15.1 inches of small and medium-size standard quasi TFT LCD module, LCD display, TFT display module, display industry, industrial LCD screen, under the sunlight visually highlight TFT LCD display, industrial custom TFT screen, TFT LCD screen-wide temperature, industrial TFT LCD screen, touch screen industry. The LCD module is very suitable for industrial control equipment, medical instruments, POS system, electronic consumer products, vehicles, and other products.

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. See our blog post RGB and Color Depth for more on how TFTs show color.

LCDs use voltage applied to a field of microscopic liquid crystals to change the crystal’s orientation. The orientation of the crystals changes the polarization of the liquid crystal creating light or dark pixels on the display.

These pixels are arranged to create characters or graphic images. This type of display may be sunlight-readable and may have a backlight, which allows it to be viewed in dark areas.

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 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.

Reports suggest that Apple is getting closer to implementing MicroLED in its future product releases, including the Apple Watch, with the display technology potentially offering a number of benefits compared to other methods. AppleInsider explains how the current TFT and OLED display technologies work, and how MicroLED differs.

MicroLED shows promise as a display technology, potentially offering power savings and a reduced screen thickness when put beside current-generation display panels. Apple has recognized the potential, and has invested heavily into developing the technology over the last few years, with a view to using it in the company"s future products.

To understand fully how MicroLED can benefit Apple, it is worth understanding how the commonly-used display technologies work in the first place, before examining how different MicroLED really is in a comparison.

The most common display technology used by consumer products today, and the oldest of the technologies examined in this article, TFT"s full name of TFT LCD stands for Thin-film-transistor liquid-crystal display. This technology is extensively used by Apple in its products, found in iPads, iPhones, MacBooks, and iMac lines.

The LCD part relates to the concept of defining small translucent or transparent areas in a thin and flexible liquid crystal-filled panel, like the displays used in calculators. Passing current through the segment changes the molecular properties of the defined segment area, allowing it to switch between being see-through or opaque.

TFT takes this a stage further, by effectively covering an entire panel with a grid of isolated liquid crystal segments, which again can vary between opaque and transparent based on the level of electrical current. In this case, there are far more segments needed to make up the display than with a normal calculator.

Polarizing filters on either side of the TFT display sandwich are used to prevent light from passing through directly, with the liquid crystal reaction of each segment affecting polarized light passing through the first filter to go through the second.

Sometimes these types of display are known as "LED," but this somewhat of a misnomer, as this actually refers to the use of Light Emitting Diodes as a light source. The LED backlight shines light through the various layers making up the TFT LCD.

Displays that use collections of LEDs as individual pixels do exist, but it isn"t usually found in consumer products. LED screens are commonly used for billboards, in attractions, and as a large-scale display for events.

TFT LCD screens continue to be widely used in production for a number of reasons. Manufacturers have spent a long time perfecting the production of the display panels to make it as cheap as possible, while its high usage allows it to benefit from economies of scale.

Used in consumer devices in a similar way to TFT LCD, OLED (Organic Light-Emitting Diode) is a display technology that is similar in the basic concept, but differs considerably in its execution. Again, the idea is for a thin panel to be divided up into segments, with charge applied to each section to alter its molecular properties, but that"s where the techniques diverge.

As the name implies, OLED uses an organic compound film that is put between two electrodes, which are used to provide charge. Instead of the charge changing how light passes through, the current instead causes the emissive electroluminescent layer to emit light, without the need for a rear light source.

These self-emitting pixels gives OLED a considerable advantage over LCD-based systems in a number of areas. Most obviously, by not needing a backlight, OLED panels can be made far thinner than an equivalent LCD-based display, allowing for the production of thinner devices or more internal area for other components, like a larger battery.

The power efficiency of OLED panels can be far greater, as while a TFT screen requires an always-on backlight, the brightness of OLED pixels themselves determine power usage, with a black pixel consuming no power at all. OLED screens are also faster to respond than LCD displays, making them more useful for VR displays, where response time needs to be as rapid as possible.

This also allows OLED to provide superior contrast ratios compared to TFT, as the lack of backlight bleed-through that occurs in TFT simply doesn"t happen in OLED.

OLED also can be produced on plastic substrates instead of glass, allowing it to be used to create flexible displays. While this is currently embodied in curved and other non-flat screens in some devices, it has the potential to be employed in foldable smartphones or rolled up for storage, an area Apple is also allegedly examining.

Despite the advantages, OLED is still lagging behind TFT in terms of adoption. The cost of production is far higher, in part due to the need for extremely clean environments, as a single speck of dust can potentially ruining a display during fabrication.

OLED panels are also affected by the presence of water, both in production and in use. Small amounts of water contacting the organic substrate can cause immediate damage to the display, rendering parts of the screen useless.

So far, Apple"s usage of OLED consists of the premium iPhone X and the Apple Watch. As the cost of production drops down, it is plausible for Apple to use OLED in more future products, providing a better screen for customers to use.

Thought to be the next big thing in display technology, MicroLED basically takes the idea of using LEDs for pixels in a large stadium-style screen and miniaturizes it all.

Using extremely small LEDs, three MicroLEDs are put together to create each pixel, with each subpixel emitting a different color from the usual red, blue, and green selection. As each LED emits light, there is no need for a backlight as used in TFT screens.

MicroLED doesn"t use an organic compound to produce light, making it less susceptible to failure compared to OLED. Just like OLED, it can be applied onto a flexible material, allowing it to be used for curved displays or non-stationary components, like a watch strap, and can result in an extremely thin display panel.

MicroLED offers the same lower power consumption and high contrast ratio benefits as OLED when compared to TFT. However, MicroLED is also capable of producing a far brighter image than OLED, up to 30 times brighter, and is in theory more efficient in converting electricity into light.

As a relatively new and in-development technology, the cost of MicroLED production is extremely high in comparison to the more established OLED and TFT mass production lines, in part due to lower than required yields. Manufacturing equipment vendors have produced hardware for MicroLED production that cuts defects in half and reduces deposition deviance from 3 nanometers down to 1 nanometer, but it is unclear if this is enough to help mass production move forward.

While MicroLED is an attractive proposition for Apple, it is not the only technology under development by the company"s engineers. Apple has previously filed patent applications for a technology described as "Quantum Dot LED and OLED Integration for High Efficiency Displays."

Quantum Dots are photoluminescent particles included in an LED-backed TFT display that can produce brighter and more vibrant colors, with the colors produced depending on their size. While available in current QLED televisions, the technology is only really being used to enhance the backlight, rather than being used to illuminate individual pixels.

Image: Lee, Changhee & BAE, Wanki & KWAK, Jeonghun. (2014). "Quantum Dot LED (QLED) Emerging as a Next-generation Display Technology" in Physics and High Technology

The technology in theory can create an even thinner display than OLED, along with a more streamlined manufacturing process. True QD displays are also capable of high pixel densities of up to 1,000ppi, multiple times the density required to be called a Retina-quality display, and based on Apple"s hybrid invention, will also boast the response times of OLED technology.

As is usually the case, Apple does produce a considerable number of patent applications every week that are filed with the US Patent and Trademark Office, and not everything it files will be fully commercialized.

The QD patent application certainly shows Apple is thinking about display technology in multiple ways, and how it can be applied to future devices, but short of getting firm supply chain information or an official announcement from Apple directly, it is difficult to confirm which direction it will be heading.

Apple has been interested in using the technology for some time now, with the first notable sign being its acquisition of LuxVue in May 2014, alongside assorted related patents. A MicroLED specialist, LuxVue was rumored to have been the display producer for the ill-fated Google Glass headset, but was also the holder of assorted patents in the LED display field, including MicroLED.

At the time, the acquisition was thought to be an attempt by Apple to bring part of its display technology development in-house, with suggestions the MicroLED technology would be used in another rumored-at-the-time device, the Apple Watch. A more recent report suggests Apple is working with TSMC to make small panels for a future premium Apple Watch, potentially starting mass production by the end of the year.

Apple has also reportedly set up a secret facility just 15 minutes away from Apple Park, believed to be used for developing MicroLED. The 62,000 square-foot facility is thought to house around 300 engineers on a project named "T159," relating directly to the technology"s development.

The facility is also claimed to be sufficient in size to perform small scale manufacturing of display panels, allowing the company to keep development and testing in-house without involving third-parties. Considering Apple"s previous history in developing technologies before issuing information to manufacturing partners, it is possible that Apple is trying to work out the kinks in production before suppliers even attempt to make MicroLED panels.

The rumored small screen production may be for the Apple Watch now, but it may also benefit another often-rumored device, namely the VR or AR headset. This type of hardware relies on light components to keep the weight off the user"s head and neck, as well as displays with a high refresh rate and as close to perfect color reproduction as possible.

Apple is also apparently planning to use the technology in larger displays, said to be bigger in size than those in the MacBook Pro lines. This could be an iMac or iMac Pro, or even an external display, but ultimately there"s no real indication of Apple"s plans at this point, regardless of the scale of the screen.

Reports from last year also suggest Apple"s investment in MicroLED was a cause for concern for Samsung, LG, and other South Korean suppliers who provide display panels for the company"s products. Owning the process for MicroLED manufacturing could allow Apple to migrate away from its existing display suppliers in the coming years, reducing revenues and profits.

Aside from Apple"s development, there has been little in the way of announcements from other firms for products using the technology that could be bought by consumers in the coming months. The exception is Samsung, Apple"s main rival in the mobile marketplace and a major supplier of display panels, but its usage of MicroLED is not aimed at producing smaller screens.

At CES 2018, Samsung introduced The Wall, a 148-inch TV claimed to be the "world"s first consumer modular MicroLED" television. According to the South Korean electronics giant, The Wall"s modularity meant consumers would be able to customize their television"s size and shape to suit their needs.

The impending use of the technology in a high-priced consumer product could be considered proof that MicroLED display technology is maturing enough for use in devices. If the reports claiming Apple is getting close to mass producing panels is true, the inclusion of MicroLED in the Apple Watch could end up being the first mainstream usage of the technology.

TFT is an abbreviation for Thin Film Transistor, a flat panel display used to improve the operation and utility of LCD screens. In order to portray an appearance to the audience, a liquid crystal display (LCD) utilizes a crystalline-filled fluid to modify rear lighting polarized origin through the use of an electromagnetic force among two relatively thin metal wires such as indium oxide (ITO). However, color TFT displays are associated with this method, which can be employed in both divided and pixelated display systems.

With motion pictures displayed on an LCD, the intrinsic sluggish rate of increase between liquid phases over a significant number of pixel components can be an issue due to capacitance impacts, which can create a blurring of the visuals. Placing a high-velocity LCD control device inside the formation of a thin-film transistor immediately next to the cell component just on a glass screen, the issue of LCD picture speed may be substantially improved, and image blur can be eliminated for all useful purposes entirely.

Organic light-emitting diodes (AMOLEDs) are a type of flat light-emitting advanced technologies that are created by interspersing a succession of organic thin sheets over two conducting conductors. An electrical charge causes a brilliant light to be produced when the current flows. AMOLED displays are light-emitting screens that do not require a backlight, making them thinner and more energy-efficient than liquid crystal displays (LCDs) (which will need a white backlight).

AMOLED displays are not only thin and fuel-intensive, but they also deliver the highest image quality available, so they can be made translucent, elastic, bendable, or even rollable and stretchy in the future, allowing for a variety of applications. AMOLEDs are a revolutionary technology in terms of display devices! It is possible to create an AMOLED by sandwiching a sequence of thin films across phase conductors. Electric charge causes a brilliant light to be emitted when the current flows through the coil.

The color display is fantastic. Color intensity, sharpness, and luminance settings that are second to none and can be customized to meet the needs of any application.

Half-Life has been expanded. TFT displays have a far longer half-life than its LED equivalents, and they are available in a number of sizes, which might have an effect on the device"s half-life based on the phone"s usage as well as other variables. Touch panels for TFT screens can be either resistant or capacitance in nature.

Due to the apparent glass panels, there is limited functionality. For instance, there are ineffective for outdoor use because the glass can display glares from its natural lighting)

They rely on backlight to give illumination rather than generating their own light. Hence they require constructed light-creating diodes (LEDs) in their backlit display framework to ensure enough brightness.

Backlighting is unnecessary for AMOLEDs. LCDs produce images by selectively blocking parts of the illumination, whereas AMOLEDs produce light. AMOLEDs utilize less energy than LCDs since they don"t need backlighting. This is critical for battery-powered devices such as phones.

While AMOLED light-emitting sheets are lightweight, the substrate can also be elastic rather than stiff. AMOLED films are not limited to glass-like LEDs and LCDs.

AMOLEDs offer 170-degree ranges of vision. LCDs operate by obscuring the light. Hence they have intrinsic viewing obstacles. In addition, AMOLEDs have a substantially wider viewing spectrum.

AMOLEDs outperform LEDs. Since AMOLED organic coatings are less than LED inorganic crystal levels, AMOLED conducting and particle emitters layers can just be multi-layered. Also, LEDs and LCDs need glass backing, which absorbs light. AMOLEDs don"t need it.

AMOLEDs seem to be simpler to implement and larger. AMOLEDs are constructed of polymers and may be produced into big sheets. It takes a lot of extra liquid crystals to build and set down.

While red and green AMOLED sheets have a greater lifespan (46,000 to 230,000 hours), azure compounds have significantly shorter longevity (up to roughly 14,000 hours).

Due to the fact that AMOLED displays inherently emit illumination, they do not need a backlight when used on a monitor screen. Conversely, LCDs require backlights since the liquid crystals themselves are incapable of producing light under their own. Direct light emission from AMOLED displays also allows for the developing of lightweight display devices than others using TFT LCDs.

LCD displays have a higher brightness than AMOLED panels. This is owing to the LCD"s usage of led backlight, which may provide a brilliant illumination of the entire display. Despite the fact that AMOLEDs produce high levels of brilliance from their illumination, they will never be able to match the intensity of LCD lighting.

LCD screens use less power than AMOLED displays, which provides a slight advantage. The amount of energy consumed by AMOLED displays is dependent on the intensity of the screen. Lowered luminance results in lower energy usage, however, it might not be the best solution because the contrast would suffer as a result of the decreased brightness. In some situations, such as when to use an AMOLED device in direct sunlight, it is not an optimal situation.

However, the backlit keys of TFT displays account for the majority of their power usage. TFT screens" efficiency is considerably improved when the backlight is set to a lesser brightness level than the default setting. For example, replacing the light of an LCD TV with just an Led flash will have no effect on the image quality, but will result in lower power usage than replacing the light of an AMOLED TV.

With the exception of phones, numerous other technologies make use of displays to allow customers to engage in direct communication with them. To determine whether or not TFT LCD will be able to withstand the development of AMOLED innovation, we should first review the benefits of LCD technology. The backlighting quality ensures that whites are strong and brightness is superb but will deplete a battery much more quickly than just an AMOLED display. Furthermore, the cost of LCD screens is a considerable consideration. In addition to being less expensive and more easily accessible, they are produced in standard industry sizes, allowing them to be purchased for innovative products with relative ease.

LCD displays don’t emit light by themselves. They need a light source, and LED backlights are now dominating the market. In this article, Orient Display’s Bill Cheung provides a complete overview of LED backlight technology, discussing different types, driver technologies, color deviation, brightness options and more.

LCD (liquid crystal display) has long been the dominant technology in the display world. Certainly, there are some emerging competing display technologies—such as OLED (Organic Light Emitting Diode) [1] and micro-LED—that have the potential to threaten LCD’s position in the market. But both are currently only used for niche and high-end markets.

An LCD display can’t emit light by itself. In order to have an LCD display [2] used in a dim environment, a backlight has to be used as the light source. There are a few different technologies that are able to produce backlight ranging from EL (electroluminescent), CCFL (cold cathode fluorescent lamps) and LED (light emitting diode). However, a breakthrough in blue LED technology by Shuji Nakamura [3] led to LED backlights dominating the market.

One of the greatest benefits of LED backlighting is its long lifetime. Normally, LED lifetime can be measured with half-life when the original brightness decreases by 50%. With different LED chip manufacturing materials, technologies and environment used, the LED life can vary from 20,000 hours to well over 100,000 hours.

LED backlights have low power consumption and produce much less heat than other backlight technologies, which extends the durability and performance of the other display components. Furthermore, this reduces the risk of fire and explosion. LED backlights are also driven with DC (direct current) and low voltage (can be as low as 1.5V), which are good for battery drive and emit no interference to the circuitry. With the development of LED technology, the LED chips become small. So, it is possible to produce very thin backlight (0.5mm thick or thinner).

Although white LED is the most popular color, LED backlight can be made into different single colors, bi-colors and tri-colors [4] (Figure 1) (Figure 2). With RGB LED backlight color mixing, normal 8 color LED backlight can be produced (Figure 3).

LED backlight can be classified as bottom (array) lit and side (edge) lit backlights, and each have their plusses and minuses. The advantages of the bottom lit (array) backlight are that it is uniform and bright. Its disadvantage is high current draw, thickness, heat dissipation and cost. Meanwhile, the advantages of the side lit backlight are its thinness, flexibility in design, low current and lower cost. The main disadvantage of the side lit backlight is its non-uniformity—hot spots can be seen from most of the side lit backlight from certain angle. Figure 4 compares the bottom lit and side (edge) lit backlight LCD types.

Now let’s look at LED backlight structures. An LED backlight can be simplified into layers starting with a LED chip, light guide, diffusor and reflector (Figure 5). This is the lowest cost structure. Except for some very low current efficiency LCD displays—such as utility meters, battery-powered clock, watch, GPS and so on—most LCD displays need backlights to be visible in the dim lighting. Most often the backlight is actually at the back of the LCD. In rare cases, this light can be done as front light. The traditional LCD structure with LED backlight shown in Figure 6.

Direct current driving: This is the simple and low-cost way to drive a LED backlight, however, be mindful of the current limit otherwise the LED life can deteriorate quickly. The solution is simply to add a current limiting resistor in the circuit. Current limitation resistors value calculation formula: R = (V0– Vf)/If.Also be mindful of reverse drive, otherwise, the LED chip can break down easily.

LED driver with constant current: The advantage of constant current LED driver is that it will be the best option to use when building your own fixture or working with high powered LED because they avoid violating the maximum current specified for the LEDs, therefore avoiding burnout/thermal runaway. They are easier for designers to control applications, and help create a more consistent bright light.

LED driver with constant voltage: Using a constant voltage LED driver makes sense when using an LED or array that has been specified to take a certain voltage. This is helpful because constant voltage is a much more familiar technology for design and installation engineers. Moreover, the cost of these systems can be lower, especially in larger scale applications.

As the LED is manufactured via the semiconductor process, there are some color deviations that can be a quality control issue. One way to solve the issue is through a process of selection and sorting after manufacturing the LEDs. The LEDs are sorted into different categories or bins. How this sorting is done and what each bin actually contains is defined differently by each LED manufacturer. The backlight manufacturer can choose from which bin they take the LEDs for backlight color hue.

Some customers might request very fine binning by the LED manufacturer, which can be very expensive since only a very small percentage of the LEDs manufactured would meet the requirements for a specific bin. Figure 7 shows an example of the bin selection from Nichia, the most renowned LED manufacturer in the world. Figure 8 shows the 1931 CIE chromaticity diagram. And Figure 9 shows the color deviations (bin definition) by Cree for a qualified production lot.

In actual LED backlight production, most customers will accept the LED color for two big categories: white with yellowish (warm) and white with bluish (cold). Of course, the LED brightness will also need to be defined. For general application, most customers will accept a brightness tolerance of 70 percent.

It is extremely hard to estimate the LED backlight lifetime or MTBF (mean time between failures) because there are so many variable factors. However, the most important is the temperature on the LED chip. The factors that can affect the LED chip temperature include: surrounding temperature, humidity, driving current, voltage, backlight design (how many LED chips to be used, how close to each other, heatsink design), backlight manufacturing process (type and thickness of adhesive), quality of the LED chip and so forth.

To test the LED life is also very time consuming, requiring at least 1,000 hours. That’s the reason why no LED manufacturers can guarantee LED backlight life and most backlight manufacturers also are reluctant to provide lifespan data. As for LCD manufacturers, they need to discuss it with the customer to understand the applications and provide suggestions. It is normal that the LCD datasheet lists the typical life time and avoids providing a minimum lifetime. From Figure 10, we can see that over room temperature, the current needs to decrease as the temperature increases. At over 85°C, the LED is not usable.

To estimate LED backlight lifetime, you can use ballpark estimation or theoretical calculation. Let’s first examine the ballpark method. To take white LED as example, the nominal biasing current is 20mA. If we use a safe lifetime estimation, we can estimate using Table 1.

Now let’s use the theoretical calculation approach. As we previously mentioned, LED life is affected by a lot of factors: surrounding temperature, humidity, driving current, voltage, backlight design (how many LED chips to be used, how close to each other, heatsink designed), backlight manufacturing process (type and thickness of adhesive), quality of the LED chip and so on. LED chip manufacturers are not willing to give absolute values of LED chip lifetimes, but there is a theoretical calculation that we can use.

Temperature is the determination factor for LED chip life, while LED chip manufacturers use LED junction temperature to predict LED chip life more accurately. An example is:

Finally, let’s look at ways to increase LED backlight brightness. There are many ways to increase LED backlight brightness, but all these measures are balanced with performance and cost. Here are some of the methods:

For the LCD module side, using better aperture opening ratio, anti-reflection coating on surface, optical bonding. This results in higher cost. Actually, this measure is not to increase LED backlight brightness directly but to increase to the visibility to users.

Bill Cheung is an engineering lead and marketing manager at Orient Display, an LCD and display technology provider with over two decades of industry experience in delivering cutting edge display solutions. You can browse Orient Display"s knowledge base [7] to learn more about LCDs.

There’s been a significant growth in the monitor market when it comes to screens with LED backlighting. I wanted to provide an article which explains the technology in more detail as it is bound to become more and more widespread. The technology was originally quite expensive, but reduced production costs and improved manufacturing processes have allowed LED backlighting to be used in even the lower cost monitor market. We are now seeing an influx of new screens in all different sizes using LED backlighting, and it is also being combined with TN Film, VA and IPS panel technologies.

RGB LED Backlighting – This type of backlighting is based on RGB triads, each including one red, one green and one blue LED. RGB LED backlighting ensures an excellent colour gamut and very pure colours, but is only really used in professional-grade displays such as the Samsung XL20, XL24, XL30 screens, and modern professional models like the HP DreamColor LP2480zx. This type of backlighting is only used in this sector due to its high cost and it is not economical to produce at the moment.

An edge backlight with white LEDs (W-LEDs) –The LEDs are placed in a line along the edge of the matrix, and the uniform brightness of the screen is ensured by a special design of the diffuser. This backlight does not offer the option of zonal control over brightness like the direct lit method does (see below). It can not offer an extended color gamut either. Instead, it is economical and compact, which makes it popular among notebook makers and with manufacturers producing ultra-thin displays and keen to keep costs to a minimum. This is the variation commonly being used in desktop displays at the moment.

A flat backlight based on white LEDs (W-LEDs) – As there is only one third of the total amount of LEDs here, this backlight is much cheaper than the triad-based backlight, but it cannot deliver an extended color gamut. In the backlight of this type LEDs are uniformly distributed in the plane parallel to the matrix, which allows setting the backlight intensity differently in different parts of the screen when necessary. This is the further development of the dynamic contrast technology. It is currently employed in LCD TV-sets only and is also referred to as ‘direct lit’ W-LED. A note about white LEDs – A white LED is actually a blue LED with yellow phosphor to give the impression of white light. The spectral curve has big gaps in the green and red parts.

If marketing is to be believed, LED backlighting offers you all kinds of advantages, but it’s important to understand what is true, and what is not. We will discuss different aspects and whether they are influenced by a different backlight source:

Colour Gamut– this is controlled in monitors by the properties of the colour filters of the LCD matrix, and by the backlight’s radiation spectrum. You will see CCFL backlighting offering colour gamuts covering between 72% (commonly referred to as “standard gamut” / sRGB) and 102% of the NTSC reference colour space. The CCFL backlighting above 72% are commonly referred to as wide gamut, or W-CCFL / WCG-CCFL. In LED backlighting, the RGB LED format can offer really large colour gamuts with pure and saturated colours. These can cover typically >114% of the NTSC colour space, and is one of the reasons they are often employed in high end professional screens. W-LED backlighting cannot offer these extended gamuts, and on paper actually cover slightly less of the NTSC colour space than standard gamut CCFL (typically 68%). The difference is hardly detectable by the naked eye however.

Static contrast ratio – LED backlighting models are advertised with massive contrast ratios, ranging commonly into the millions now! Figures of up to 20 million:1 are common at the time of writing. Be aware though that these are normally headline dynamic contrast ratio figures, with the normal static contrast ratio rarely even mentioned. It is important to understand that static contrast ratio is only determined by the characteristics of the LCD matrix itself and not by the backlighting type or nature. It is determined by the ratio of the transparency levels of open and closed pixels.

Dynamic contrast ratio – As opposed to gas-discharge lamps (CCFL), LEDs can be lit up instantly or turned out completely. This can lead to extremely high levels of dynamic contrast as we have mentioned above. Figures in the millions are very common now. But in real applications, for example when watching a movie, there are no absolutely black frames even in the credits. Most of the time there is something on the screen besides blackness and a monitor with a huge specified dynamic contrast will never have the chance to deliver it in practice. As a result, there is no real practical point in increasing the dynamic contrast higher than about 10,000:1 which has already become standard for many monitors, including those with a backlight based on CCFL lamps. Keep in mind that DCR figures are often exagerated as a result, and since you will probably never get to utlise the full figure in practice, don’t be fooled into buying into the hype too much