This article talks about some of common display types in mobiles.There are lot of display types used in mobile phones.
Different Types of Mobile Displays
The color displays usually are CSTN, TFT, TFD, LCD, AMOLED, OLED, SLCD with a predominant use of TFT displays in current mobile lineups. There are also two types of touchscreen displays – capacitive and resistive, which are both based on TFT technology. Capacitive touchscreens work by sensing the electrical properties of the human body, while Resistive ones operate by sensing direct pressure applied by the user.
The resistive type can be activated by pressing not only with human skin but also with a stylus and thus allow handwriting recognition input.
TFT LCD (Thin film transistor):
Thin film transistor liquid crystal display (TFT LCD) is a variant of liquid crystal display (LCD). It uses thin-film transistor (TFT) technology to enhance image quality. It is the most common display technology used in mobile phones. It offers better image quality and higher resolutions as compared to earlier generation LCD displays. The only limitations are narrow viewing angles and poor visibility in direct light or sunlight. Further, large TFT displays consume more power and hence, are not battery-friendly. As this display technology is cheaper to manufacture, these are most commonly found on budget phones, feature phones and low-end smartphones.
CSTN (Color Super Twisted Nematic):
STN is a type of LCD display technology. STN is black and white while CSTN is the color version. (C)STN displays are used on lower end devices.
Typically an STN display has worse image quality and response times than a TFT LCD, but is cheaper and more energy efficient.
IPS LCD (in-plane switching):
IPS (in-plane switching) LCD offers better display quality than normal TFT LCD display. It offers wider viewing angles and consumes less power, which in turn gives a much improved battery life. This technology is costlier than normal TFT LCD and hence, is found only on high-end smartphones. Apple uses a high resolution (640×960 pixels) version of IPS LCD in its iPhone 4, which is also called Retina Display because of its excellent picture quality.
In addition, LG’s new Optimus LTE has a 4.5–inch True HD IPS display, developed in close collaboration with sister company LG Display, offers advanced resolution, brightness and clarity and shows colours in their most natural tones, as they were meant to be seen.
TFT (Thin Film Transistor):
TFT is one of the best Liquid Cristal Display technologies in terms of image quality and response time. However, it also consumes more power and is more expensive.
TFT, like TFD, is an active-matrix technology. This means a transistor is located next to each pixel, allowing it to be turned on and off individually. This ensures faster response time and greater contrast.
Super LCD (SLCD):
It is an upgradade of the erstwhile LCD technology. While both display technologies are efficient with colours and brightness, SLCD scores over AMOLED in very sunny conditions. SLCD gives warmer colour tones and has better colour definition than AMOLED (described below) display technology.
TFD (Thin Film Diode):
TFD is a kind of Liquid crystal display (LCD) technology. It is an active-matrix technology which means that a diode is situated next to each pixel making it possible for the pixels to be turned on and off individually. This allows a quicker response time and more contrast than passive-matrix technologies.
TFD takes the excellent picture quality and the fast response of TFT displays and combines them with the low power consumption and cost of the STN ones.
OLED (Organic Light-Emitting Diode):
OLED (Organic Light Emitting Diode) display technology is much better than LCD display technology because of its excellent colour reproduction, faster response times, wider viewing angles, higher brightness and extremely light weight designs.
A display technology that consists of small dots of organic polymer which emit light when charged with electricity.
OLED displays have several advantages over the LCDs. They are thinner, lighter, brighter, need less power, have better viewing angles, contrast and response time for video and animation. OLEDs are also cheaper and easier to manufacture.
On the other hand, LCDs offer better legibility in bright ambient light.
AMOLED (Active-matrix organic light-emitting diode):
There is no substantial difference between the two – OLED AND AMOLED (Active-Matrix Organic Light-Emitting Diode). Active Matrix, which is a method for controlling individual pixels. AMOLED display technology is a type of OLED display for mobiles and is rapidly gaining popularity in high end smartphone segment. AMOLED screens include all the attributes of an OLED display like excellent colour reproduction, faster response times, wider viewing angles, higher brightness and extremely light weight designs. However, in terms of vibrancy and brilliance, AMOLED beats SLCD display technology. There are many high-end phones using this technolgoy like Nokia N8. If you can shell out money, it is suggested to opt for AMOLED display over TFT LCD.
AMOLED is an emerging display technology used in portable devices like mobile phones. Active-matrix OLED displays provide the same performance as their passive-matrix OLED counterparts, but they consume significantly less power.
This advantage makes active-matrix OLEDs well suited for portable electronics where battery power consumption is critical.
Super AMOLED (Active-matrix organic light-emitting diode):
Super AMOLED display technology is an advanced version of AMOLED display. Developed by Samsung, it is said to be the thinnest display technology in the market. Super AMOLED display is much more responsive than an AMOLED display. Samsung top-of-the-line Galaxy SII comes engineered with Super AMOLED display technology.
Retina Display is a term used by Apple for its high resolution (640×960 pixels) IPS LCD display technology used in iPhone4. The company calls it the Retina display because its pixels cannot be individually identified by a human eye, thereby making the display super sharp, text more crisp and pictures more clear.
Resistive touchscreens possesses two layers of conductive material with a very small gap between them, which acts as a resistance. When the resistive touchscreen is touched with a finger (or a stylus) the two layers meet at the point of touch and thus makes a circuit there. Resistive touchscreens are not as responsive as capacitive touchscreens and hence, often require a stylus. This technology is cheaper to make and is used only in low end phones.
Resistive touchscreens operate by sensing direct pressure applied by the user. It can be activated by pressing it not only with a finger but also with a stylus (unlike the competing capacitive technology).
A resistive touch screen consists of a touch layer placed on top of a standard display. The touch layer normally includes two transparent electrical layers separated by a small gap.
Pressing the display’s surface causes the two separate layers to come into contact, which creates an electrical connection that can be sensed and located.
Capacitive touchsceens are more responsive to human touch when compared to resistive touchsceens. Hence, the user experience for touch is much better. Capacitive touchsceens are used in high-end smartphones. A capacitive screen is smooth to operate as it just requires the presence of your finger, without any pressure.
Capacitive touch sensors are used either as buttons or on touchscreens. They work by sensing the electrical properties of the human body instead of pressure and generally they don’t work with a stylus so they don’t allow handwriting recognition. However, capacitive touchscreens feel more sensitive than their resistive counterparts. Capacitive touch screens are also considered more durable than resistive touch screens.
In combination to all that has been described above, there is also Gorilla Glass which is now used in high-end phones. It is basically a glass shield with exceptional damage resistance that helps users protect mobile displays from scratches, drops, and bumps. Leading mobile phone manufacturers such as Motorola, Samsung and Nokia are now using Gorilla Glass to make their mobile displays more durable.