There are many different types of displays /
touchscreens available across the range of smartphones and it is important that
we know about them before buying one. Over last one year smartphones with large
smartphone displays and touchscreens have really become popular. In this post
we explain different types of displays and touchscreens and their pros and
cons.
1. TFT LCD
Very popular among smartphones, provides better image quality than earlier generation LCD displays but ends up consuming a lot of power hence reducing battery backup.
Relatively expensive hence usually found on high-end devices only, provides better viewing angles and consumes less power than TFT LCD displays.
Organic Light Emitting Diode
(OLED)
It is a thin-film display technology that contains OLED, an organic material which emits light when current is passed through it.
OLEDs display much better blacks and consume less power when displaying darker colors since OLEDs are always off unless electrified individually.
There are primarily two types of OLEDs:
1. PMOLED
Passive Matrix Organic Light Emitting Diode uses a simple control scheme in which each row in the display is controlled sequentially.
PMOLEDs are easy and cheap to fabricate but they are not efficient and their lifetime is usually less.
They are typically used in smaller displays of up to 3 inches.
Active Matrix Organic Light Emitting Diode is mainly driven by a TFT, which contains a storage capacitor and can hence support larger displays.
AMOLED displays have no size restrictions and work on the same fundamental principles of an OLED display.
Advantages
Disadvantages
Super AMOLED
Super AMOLED displays are advanced version of AMOLED developed by Samsung.
When compared with a regular LCD display an AMOLED display consumes less power, provides more vivid picture quality, and renders faster motion response as compared to other display technologies such as LCD.
However, Super AMOLED is even better at this with 20% brighter screen, 20% lower power consumption and 80% less sunlight reflection.
Retina Display
Retina Display is a term used by Apple for its high resolution (640 x 960 pixels) IPS LCD (with backlit LED) used by them in iPhone4.
They call it the Retina display because its pixels cannot be individually identified by the human eye, thus making the display super sharp and brilliant.
High Definition (HD)
HD simply means a pixel measurement of 1,280 x 720 pixels.
On a 4.3-inch screen, for example, the pixel density is 342 ppi. On a 4.7-inch screen, the pixel density drops to 312 ppi, but both are still HD displays.
Full HD
Full HD measures 1,920 x 1,280 pixels.
Again, the pixel density will depend on how large the screen diagonal. With smartphones at the 5-inch mark, the pixel density sits around 440 ppi , while on a 5.5-inch screen that number drops to 400 ppi .
QHD, Quad HD or 2K
QHD stands for Quad HD, which is four times the definition of standard HD. That means you can fit the same number of pixels as four HD displays into a QHD display of the same size. The pixel measurement for QHD is 2,560 x 1,440 pixels.
A 5.5-inch QHD display has a pixel density of 538 ppi . For comparison, the pixel density of a 5.5-inch Full HD screen is 400ppi.
4K or Ultra HD
Like 2K, the 4K name comes from the larger of the two pixel measurements, which are, technically speaking, 4,096 pixels in 4K and only 3,840 pixels in Ultra HD. So while these two terms are often used interchangeably, they are actually a little bit different.
Resolution Trends
HD to Full HD to QHD the pixel densities increased too: from 342 ppi, to 441 ppi, to 538 ppi and now we're looking at 806 ppi .
Even though screens get bigger, the pixels get denser at a faster rate. This means image quality has improved dramatically because rapidly increasing pixel densities are appearing on screens that aren't significantly large.
SMARTPHONE
TOUCHSCREENS
Resistive
Touchscreen LCD
Resistive touchscreens contain two layer of conductive material with a very small gap between them which acts as a resistance. When the resistive touchscreen is touched with finger (or stylus) the two layers meet at the point of touch thus making a circuit at the point of touch. This information is recognized by the mobile’s processor / chip and passed on to the mobile’s OS there by triggering and event / action at the point of touch.
Resistive Touchscreens are not as responsive as capacitive touchscreens and often require a stylus to identify point of touch accurately. These are used only in lower end smartphones and feature touch phones.
Capacitive
Touchscreen LCD
Capacitive touchscreen technology consists of a layer of glass coated with a transparent conductor (like indium tin oxide). When a capacitive touchscreen is touched by human body (finger), an interruption is created in the screens electrostatic field (which is measurable as a change in capacitance) which is detected by phone’s processor or chip and which in turn instructs phone’s operating system to trigger and event or action accordingly.
Capacitive touchscreens are much better and responsive to human touch when compared to resistive touchscreens and hence the user experience for touch is much better with capacitive touchscreens.
Capacitive Touchscreens are used in most of the higher end smartphones.
Haptic / Tactile Touchscreen
Haptic technology has been used by Blackberry and Nokia for their touchscreen smartphones targeted towards enterprise market. This technology provides a tactile feedback on a touch action on the screen thus providing an immediate and unmistakable confirmation to the user.
Haptic technology has been found to significantly improve user performance, accuracy and satisfaction while typing on a touchscreen.
Projected Capacitance
Projected capacitive touch (PCT; also PCAP) technology is a variant of capacitive touch technology.
All PCT touch screens are made up of a matrix of rows and columns of conductive material, layered on sheets of glass. This can be done either by etching a single conductive layer to form a grid pattern of electrodes, or by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form a grid. Voltage applied to this grid creates a uniform electrostatic field, which can be measured.
Infrared Touchscreen
This touchscreen uses an array of X-Y infrared LED and photo detector pairs around the edges of the screen to detect a disruption in the pattern of LED beams. These LED beams cross each other in vertical and horizontal patterns. This helps the sensors pick up the exact location of the touch.
A major benefit of such a system is that it can detect essentially any input including a finger, gloved finger, stylus or pen.
It is generally used in outdoor applications and point of sale systems which can’t rely on a conductor (such as a bare finger) to activate the touchscreen.
Unlike capacitive touchscreen, infrared touchscreens do not require any patterning on the glass which increases durability and optical clarity of the overall system.
Infrared touchscreens are sensitive to dirt/dust that can interfere with the IR beams, and suffer from parallax in curved surfaces and accidental press when the user hovers his/her finger over the screen while searching for the item to be selected.
Gorilla Glass is a special alkali-aluminosilicate glass shield with exceptional damage resistance that helps protect mobile displays from scratches, drops, and bumps of everyday use.
Cheap glass is at more risk and it costs us more. If we buy a smartphone and by mistake display may break it will be very costly for us. Many companies like Motorola, Samsung and Nokia are now using Gorilla Glass to make their mobile displays more durable and reliable. It is always better to go for a smartphone with Gorilla Glass for that added protection and peace of mind.
An LCD is made up of some liquid crystals that get illuminated by a fluorescent
backlight.
There are mainly two types of LCD displays used on smartphones :
There are mainly two types of LCD displays used on smartphones :
1. TFT LCD
Very popular among smartphones, provides better image quality than earlier generation LCD displays but ends up consuming a lot of power hence reducing battery backup.
2. IPS LCD
Relatively expensive hence usually found on high-end devices only, provides better viewing angles and consumes less power than TFT LCD displays.
Advantages
1. Comparatively better
display under direct sunlight
2. Consistent consumption
of power
3. Not affected by color
on the display
Disadvantages
1. Blacks tend to appear
gray, lack of contrast
2. Comparatively lower
picture quality
Organic Light Emitting Diode
(OLED)
It is a thin-film display technology that contains OLED, an organic material which emits light when current is passed through it.
OLEDs display much better blacks and consume less power when displaying darker colors since OLEDs are always off unless electrified individually.
There are primarily two types of OLEDs:
1. PMOLED
Passive Matrix Organic Light Emitting Diode uses a simple control scheme in which each row in the display is controlled sequentially.
PMOLEDs are easy and cheap to fabricate but they are not efficient and their lifetime is usually less.
They are typically used in smaller displays of up to 3 inches.
2. AMOLED
Active Matrix Organic Light Emitting Diode is mainly driven by a TFT, which contains a storage capacitor and can hence support larger displays.
AMOLED displays have no size restrictions and work on the same fundamental principles of an OLED display.
Advantages
1. Thinner and more
flexible than LCD displays
2. Faster refresh rate
3. No restriction on size
of display
4. Higher contrast ratio
5. Consumes less power
when darker colors are displayed
Disadvantages
1. No backlight hence poor
display under direct sunlight
2. Consumes more power
when brighter colors are displayed
3. Organic material is
used hence it has a shorter lifetime
Super AMOLED
Super AMOLED displays are advanced version of AMOLED developed by Samsung.
What Samsung says about this display -
It consists of a set of
thin film layers of electroluminescent power-producing organic compounds and a
pixel-modulating matrix.
Super AMOLED is a more advanced version and it integrates touch-sensors and the actual screen in a single layer.
Super AMOLED is a more advanced version and it integrates touch-sensors and the actual screen in a single layer.
When compared with a regular LCD display an AMOLED display consumes less power, provides more vivid picture quality, and renders faster motion response as compared to other display technologies such as LCD.
However, Super AMOLED is even better at this with 20% brighter screen, 20% lower power consumption and 80% less sunlight reflection.
POLED
POLED ( Plastic Organic Light Emitting Diode ) is a flexible OLED panel that paves the way for different shaped devices. These flexible panels use plastic. Plastic displays is present in LG G Flex curved smartphones.
Retina Display
Retina Display is a term used by Apple for its high resolution (640 x 960 pixels) IPS LCD (with backlit LED) used by them in iPhone4.
They call it the Retina display because its pixels cannot be individually identified by the human eye, thus making the display super sharp and brilliant.
DISPLAY RESOLUTION
High Definition (HD)
HD simply means a pixel measurement of 1,280 x 720 pixels.
On a 4.3-inch screen, for example, the pixel density is 342 ppi. On a 4.7-inch screen, the pixel density drops to 312 ppi, but both are still HD displays.
According to Apple, 300 ppi is the
sweet spot, because that is roughly the point at which the human eye stops
being able to discern individual pixels at a certain viewing distance (and on a
certain sized screen).
Full HD
Full HD measures 1,920 x 1,280 pixels.
Again, the pixel density will depend on how large the screen diagonal. With smartphones at the 5-inch mark, the pixel density sits around 440 ppi , while on a 5.5-inch screen that number drops to 400 ppi .
QHD, Quad HD or 2K
QHD stands for Quad HD, which is four times the definition of standard HD. That means you can fit the same number of pixels as four HD displays into a QHD display of the same size. The pixel measurement for QHD is 2,560 x 1,440 pixels.
A 5.5-inch QHD display has a pixel density of 538 ppi . For comparison, the pixel density of a 5.5-inch Full HD screen is 400ppi.
Definitions are also often referred to by the
smaller number of the pixel measurement. Therefore HD called as 720p, Full HD gets called 1,080p and so on. With
QHD though, the 2K name comes from the fact that the bigger of the pixel
measurements is over 2,000 pixels.
4K or Ultra HD
Like 2K, the 4K name comes from the larger of the two pixel measurements, which are, technically speaking, 4,096 pixels in 4K and only 3,840 pixels in Ultra HD. So while these two terms are often used interchangeably, they are actually a little bit different.
Ultra HD is 3,860 x 2,160 pixels and 4K is 4,096 x 2,160 . Both definitions
frequently get shortened to 2,160p and the pixel difference is relatively
marginal, but there is a difference.
At one point, it seemed like we'd never see a 4K display in a smartphone, but then Sony released the Xperia Z5 Premium, which offered Ultra HD resolution on a 5.5-inch screen.
At one point, it seemed like we'd never see a 4K display in a smartphone, but then Sony released the Xperia Z5 Premium, which offered Ultra HD resolution on a 5.5-inch screen.
Sony refers to this display as 4K, but it
actually uses the smaller measurement of Ultra HD, "not real" 4K
definition. Nevertheless, the Z5 Premium has a pixel density of 806 ppi – far
beyond what any sane person would consider necessary on a smartphone held 10
inches from your face – but the very least you can display the 4K video shot
with the Z5 Premium on the Z5 Premium.
Resolution Trends
HD to Full HD to QHD the pixel densities increased too: from 342 ppi, to 441 ppi, to 538 ppi and now we're looking at 806 ppi .
Even though screens get bigger, the pixels get denser at a faster rate. This means image quality has improved dramatically because rapidly increasing pixel densities are appearing on screens that aren't significantly large.
Of course, these kinds of resolutions mean
nothing until the hard work is done to make them worthwhile: if your apps, user
interface and web experience are all optimized for Full HD rather than QHD,
then all those extra pixels are going to waste. Not to mention the additional
strain on your battery to push all those extra pixels around your screen.
SMARTPHONE
TOUCHSCREENS
Resistive
Touchscreen LCD
Resistive touchscreens contain two layer of conductive material with a very small gap between them which acts as a resistance. When the resistive touchscreen is touched with finger (or stylus) the two layers meet at the point of touch thus making a circuit at the point of touch. This information is recognized by the mobile’s processor / chip and passed on to the mobile’s OS there by triggering and event / action at the point of touch.
Resistive Touchscreens are not as responsive as capacitive touchscreens and often require a stylus to identify point of touch accurately. These are used only in lower end smartphones and feature touch phones.
Capacitive
Touchscreen LCD
Capacitive touchscreen technology consists of a layer of glass coated with a transparent conductor (like indium tin oxide). When a capacitive touchscreen is touched by human body (finger), an interruption is created in the screens electrostatic field (which is measurable as a change in capacitance) which is detected by phone’s processor or chip and which in turn instructs phone’s operating system to trigger and event or action accordingly.
Capacitive touchscreens are much better and responsive to human touch when compared to resistive touchscreens and hence the user experience for touch is much better with capacitive touchscreens.
Capacitive Touchscreens are used in most of the higher end smartphones.
Haptic / Tactile Touchscreen
Haptic technology has been used by Blackberry and Nokia for their touchscreen smartphones targeted towards enterprise market. This technology provides a tactile feedback on a touch action on the screen thus providing an immediate and unmistakable confirmation to the user.
Haptic technology has been found to significantly improve user performance, accuracy and satisfaction while typing on a touchscreen.
Projected Capacitance
Projected capacitive touch (PCT; also PCAP) technology is a variant of capacitive touch technology.
All PCT touch screens are made up of a matrix of rows and columns of conductive material, layered on sheets of glass. This can be done either by etching a single conductive layer to form a grid pattern of electrodes, or by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form a grid. Voltage applied to this grid creates a uniform electrostatic field, which can be measured.
When a conductive object, such as a finger,
comes into contact with a PCT panel, it distorts the local electrostatic field
at that point. This is measurable as a change in capacitance. If a finger
bridges the gap between two of the "tracks", the charge field is
further interrupted and detected by the controller.
The capacitance can be changed and measured at
every individual point on the grid (intersection). Therefore, this system is
able to accurately track touches. Due to the top layer of a PCT being
glass,
It is a more robust solution than less costly resistive
touch technology. Additionally, unlike traditional capacitive touch technology,
it is possible for a PCT system to sense a passive stylus or gloved fingers.
However, moisture on the surface of the panel,
high humidity, or collected dust can interfere with the performance of a PCT
system.
Infrared Touchscreen
This touchscreen uses an array of X-Y infrared LED and photo detector pairs around the edges of the screen to detect a disruption in the pattern of LED beams. These LED beams cross each other in vertical and horizontal patterns. This helps the sensors pick up the exact location of the touch.
A major benefit of such a system is that it can detect essentially any input including a finger, gloved finger, stylus or pen.
It is generally used in outdoor applications and point of sale systems which can’t rely on a conductor (such as a bare finger) to activate the touchscreen.
Unlike capacitive touchscreen, infrared touchscreens do not require any patterning on the glass which increases durability and optical clarity of the overall system.
Infrared touchscreens are sensitive to dirt/dust that can interfere with the IR beams, and suffer from parallax in curved surfaces and accidental press when the user hovers his/her finger over the screen while searching for the item to be selected.
Gorilla Glass
Gorilla Glass is a special alkali-aluminosilicate glass shield with exceptional damage resistance that helps protect mobile displays from scratches, drops, and bumps of everyday use.
Cheap glass is at more risk and it costs us more. If we buy a smartphone and by mistake display may break it will be very costly for us. Many companies like Motorola, Samsung and Nokia are now using Gorilla Glass to make their mobile displays more durable and reliable. It is always better to go for a smartphone with Gorilla Glass for that added protection and peace of mind.
So next time someone asks you about their TFT
vs IPS capacitive touchscreen, or ask you for advice about mobile display
types, you are now more informed.
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