Touch screens were introduced in mobile phones in the year 2000 for the first time and have become an integral part of almost every smartphone today. There are several types of touch screens used in monitors and mobiles. Some of the most popular are discussed below:
TFT LCD
A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive-matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.
TFT LCDs are used in appliances including television sets, computer monitors, mobile phones, handheld devices, video game systems, personal digital assistants, navigation systems, projectors, and dashboards in automobiles.
TFT (Thin Film Transistor) LCD display is used for better image quality and high resolution. Since they are cheap to manufacture, they are found in budget phones usually.
IPS-LCD
IPS (in-plane switching) is a screen technology for liquid-crystal displays (LCDs). In IPS, a layer of liquid crystals is sandwiched between two glass surfaces. The liquid crystal molecules are aligned parallel to those surfaces in predetermined directions (in-plane). The molecules are reoriented by an applied electric field, whilst remaining essentially parallel to the surfaces to produce an image. It was designed to solve the strong viewing angle dependence and low-quality color reproduction of the twisted nematic field effect (TN) matrix LCDs prevalent in the late 1980s.
IPS (In-Place Switching) LCDs are somewhat the advanced version of TFT LCDs in way that they offer improved displays and are more battery friendly. Hence, they are found in high-end phones.
RESISTIVE AND CAPACITIVE
There are generally two types of touchscreen LCD displays; Resistive and Capacitive. A resistive touchscreen has two layers of conductive material with a small gap between them while a capacitive touchscreen consists of a layer of glass coated with a transparent conductor. Capacitive screens tend to be more responsive than resistive screens and are therefore found in high-end phones mostly.
OLED
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications.
There are two main families of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell (LEC) which has a slightly different mode of operation. An OLED display can be driven with a passive-matrix (PMOLED) or active-matrix (AMOLED) control scheme. In the PMOLED scheme, each row (and line) in the display is controlled sequentially, one by one, whereas AMOLED control uses a thin-film transistor (TFT) backplane to directly access and switch each individual pixel on or off, allowing for higher resolution and larger display sizes.
OLED is fundamentally different from LED which is based on a p-n diode structure. In LEDs doping is used to create p- and n- regions by changing the conductivity of the host semiconductor. OLEDs do not employ a p-n structure. The doping of OLEDs is used to increase radiative efficiency by direct modification of the quantum-mechanical optical recombination rate. Doping is additionally used to determine the wavelength of photon emission.
An OLED display works without a backlight because it emits visible light. Thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions (such as a dark room), an OLED screen can achieve a higher contrast ratio than an LCD, regardless of whether the LCD uses cold cathode fluorescent lamps or an LED backlight. OLED displays are made in the same way as LCDs, but after TFT (for active matrix displays), addressable grid (for passive matrix displays), or indium-tin-oxide (ITO) segment (for segment displays) formation, the display is coated with hole injection, transport and blocking layers, as well with electroluminescent material after the first 2 layers, after which ITO or metal may be applied again as a cathode and later the entire stack of materials is encapsulated. The TFT layer, addressable grid, or ITO segments serve as or are connected to the anode, which may be made of ITO or metal. OLEDs can be made flexible and transparent, with transparent displays being used in smartphones with optical fingerprint scanners and flexible displays being used in foldable smartphones.
OLED (Organic Light Emitting Diode) is a newer technology used in mobiles and monitors for display. They are better than LCDs because they offer fast response times, wider viewing angles, and higher brightness. AMOLED (Active-Matrix Organic Light-Emitting Diode) and SUPER AMOLED displays are types of OLED displays.
Golden Margins –Entire Range of Touchscreen Products
We hope you found these touchscreen or panel PC fundamentals informative. Goldenmargins offers a broad selection of Industrial Touchscreen Monitors and Touch Panel PCs in various sizes and configurations, including medical touch screens, sunlight-readable touch screens, open-frame touch screens, and waterproof touch panels, as well as other unique touch screen or panel PC designs. You can learn more about our services HERE or by calling us at +86 755 23191996 or sales@goldenmargins.com
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