What is a Touch Screen Technology & Its Working

Touch screen technology is the direct manipulation type of gesture-based technology. Direct manipulation is the ability to manipulate the digital world inside a screen. A Touch screen is an electronic visual display capable of detecting and locating a touch over its display area. This is generally referred to as touching the display of the device with a finger or hand. This technology most widely used in computers, user interactive machines, smartphones, tablets, etc to replace most functions of the mouse and keyboard.

Touch screen technology has been around for a number of years but advanced touch screen technology has come on in leaps and bounds recently. Companies are including this technology in more of their products. The three most common touch screen technologies include resistive, capacitive, and SAW (surface acoustic wave). Most low-end touch screen devices contain a standard printed circuit plug-in board and are used on SPI protocol. The system has two parts, namely; hardware and software. The hardware architecture consists of a stand-alone embedded system using an  8-bit microcontroller,  several types of interface, and driver circuits. The system software driver is developed using an interactive C programming language.

What is a Touch Screen Technology?

A touch screen technology is the assembly of a touch panel as well as a display device. Generally, a touch panel is covered on an electronic visual display within a processing system. Here the display is an LCD otherwise OLED whereas the system is normally like a smartphone, tablet, or laptop. A consumer can give input through simple touch gestures by moving the screen using a special stylus otherwise fingers. In some kinds of touch screens, some normal otherwise gloves are used which are coated to work properly whereas others may simply work with the help of a special pen.

The operator uses the touch screen to respond to what is displayed and if the software of the device permits to control how it can be exhibited like zooming the screen to enhance the size of the text. So touch screen allows the operator to communicate directly through the displayed information instead of using a touchpad, mouse, etc. Touch screens are used in different devices like personal computers, game consoles, EVMs, etc Touch screens are also essential in educational institutions like classrooms in the colleges.

Who Invented Touch Screen?

The first concept of a touch screen was described & published in the year 1965 by E.A. Johnson. So, the first touch screen was developed in the 1970s by CERN engineers namely Bent Stumpe 7 Frank Beck. The first touch screen device was created & used in year 1973. The first resistive touch screen was designed in 1975 by George Samuel Hurst however wasn’t launched 7 used until 1982.

How Does Touch Screen Technology Work?

Different types of touchscreen technology work in different methods. Some can detect simply one finger at a time & get very confused if you seek to push in two positions at once. Other types of screens can simply notice and differentiate above one key push at once. There are different components used in touchscreen technology which include the following.

A basic touch screen is having a touch sensor, a controller, and a software driver as three main components. The touch screen is needed to be combined with a display and a PC to make a touch screen system.

Touch Sensor

The sensor generally has an electrical current or signal going through it and touching the screen causes a change in the signal. This change is used to determine the location of the touch of the screen.

Controller

A controller will be connected between the touch sensor and PC. It takes information from the sensor and translates it for the understanding of PC. The controller determines what type of connection is needed.

Software Driver

It allows computers and touch screens to work together. It tells OS how to interact with the touch event information that is sent from the controller.

Modes of Touch Screen

The operation of the touch screen can be done in different ways like single tap, double-tap, touch and hold, swipe, pinch.

• In a single tap, a single touch is used to tap on the screen to open an app otherwise choose an object.
• In double-tap, multiple touches are used for serving different functionalities like zooming a display, choose a word or set of words.
• The touch and hold option is mainly used to choose an object to drag it and also it gives the option to unlock the screen otherwise powering ON/OFF.
• Swiping a finger over the screen is used to type the letters using the keyboard on the screen. It is also used to move the pages from right to left and also close unwanted apps.
• In pinch, two fingers are used to zoom in or zoom out a display.

Types of Touch Screen Technology

The Touch screen is a 2-dimensional sensing device made of 2 sheets of material separated by spacers. There are four main touch screen technologies: Resistive, Capacitive, Surface Acoustical wave (SAW), and infrared (IR).

Resistive

The resistive touch screen is composed of a flexible top layer made of polythene and a rigid bottom layer made of glass separated by insulating dots, attached to a touch screen controller. Resistive touch screen panels are more affordable but offering only 75% of the light monitor and the layer can be damaged by sharp objects. The resistive touch screen is further divided into 4-, 5-, 6-, 7-, 8- wired resistive touch screen. The construction design of all these modules is similar but there is a major distinction in each of its methods to determine the coordinates of the touch.

Capacitive

A capacitive touch screen panel is coated with a material that stores electrical charges. The capacitive systems can transmit up to 90% of the light from the monitor. It is divided into two categories. In Surface-capacitive technology, only one side of the insulator is coated with a conducting layer.

Whenever a human finger touches the screen, the conduction of electric charges occurs over the uncoated layer which results in the formation of a dynamic capacitor. The controller then detects the position of touch by measuring the change in capacitance at the four corners of the screen.

In projected capacitive technology, the conductive layer (Indium Tin Oxide) is etched to form a grid of multiple horizontal and vertical electrodes. It involves sensing along both the X and Y axis using clearly etched ITO pattern. For increasing the accuracy of the system, the projective screen contains a sensor at every interaction of the row and column.

Infrared

An infrared touch screen technology, an array of X and Y axis is fitted with pairs of IR LEDs and photodetectors. Photodetectors will detect any image in the pattern of light emitted by the Leds whenever the user touches the screen.

Surface Acoustic Wave

The surface acoustic wave technology contains two transducers placed along the X-axis and Y-axis of the monitor’s glass plate along with some reflectors. When the screen is touched, the waves are absorbed and a touch is detected at that point. These reflectors reflect all electrical signals sent from one transducer to another. This technology provides excellent throughput and quality.

Virtual Touch Screen Technology

A virtual touch screen is a user interface system that enhances essential objects into reality either using an optical display or projector using sensors to follow an interaction of a person through an object. For example, a person can create a rear projector system or a display to create three-dimensional images which come into view to float within midair.

Some systems use a display with an optical head-mounted to enlarge the practical objects onto the crystal clear display through sensors to decide visual as well as physical interactions through the projected virtual objects.

PCAP Touch Screen Technology

The PCAP or Projected Capacitive touch screen technology provides the accessible multi-touch experience through tablets, smartphones to operate through extremely light touch using an extremely tough glass surface. These are strong and easily set with protecting glass & the main feature of this technology is a multi-touch function for up to ten fingers by enabling signal control.

These touch screens are equipped with a network of electrodes such as Silver Nanowire, Metal Mesh & ITO which project an electromagnetic field the passes throughout a protecting glass. Once the field alters at one end because of a touching finger, the position of touch can be designed as well as forward toward the controller.

The PCAP touch screens include a mainly scratch-resistant glass surface. Using optional protecting glasses, these screens are vandal-proof & can be utilized in public areas. But, the several touchpoints may change based on the force of the protecting glass used. These types of touch screens are ideal for recent True Flat designs like smartphones otherwise tablet PCs.

Optical Imaging Touchscreen Technology

Optical sensors are used to identify the touch; so this technology is very popular because of scalability & versatility. This technology mainly depends on infrared lights. Two IR imaging sensors are arranged at the summit, which doubles up like emitters as well as retro-reflective tapes on the three sides. The produced lights are replicated back toward the imaging sensors, which turn into blocked at the end of touch & generate a shadow to place the touch.

Acoustic Pulse Recognition Touchscreen

An Acoustic Pulse Recognition Touch screen is designed with a glass cover & four transducers connected to the back exterior. Once the screen is stroked, the friction will create acoustic signals. The transducers notice the audio signal, and then it is changed into a signal. These screens are durable, scalable & water-resistant.

Transparent Touch Screen Technology

Transparent touch screens work by using two modern technologies to make a cutting-edge display that is tough to ignore. These touch screens deliver 4K images or HD based on the display size similar to a normal professional screen. The main difference between a transparent and normal touch screen is a clear screen substrate. White pixels appear completely transparent, black pixels not clear. The full variety of RGB colors has the properties of semi-transparent. Transparent touch screens are available in different types like transparent LCD screens and transparent OLED screens.

Why Some Touch Screens Work Only with a Bare Finger?

Once a bare finer is used to tap on the screen then it registers the commands. If you use a gloved finger otherwise a stylus pen then it doesn’t register the commands. So the main reason is conductive properties. There are different kinds of touchscreen technologies available in the market, but the capacitive type is more popular as compared to others because 90% of the touch screens sold and shipped worldwide are powered through capacitive technology.

These touchscreens depend on conductivity to notice touch commands. If you use a stylus or gloved finger to control them, then they won’t record the commands otherwise react to your commands.

Application – Remote Control using Touch Screen Technology

The touch screen is one of the simplest PC interfaces to use, for a larger number of applications. A touch screen is useful for easily accessing the information by simply touching the display screen. The touch screen device system is useful in ranging from industrial process control to home automation.

In real-time by simply touching the touch screen and with a graphical interface, everyone can monitor and control complex operations.

At the transmission end using a touch screen control unit, some directions will send to the robot for moving into a specific direction like forwarding, backward, rotating left, and rotating right. At the receiving end, four motors are interfaced with the microcontroller. Two of them will be used for Arm and grip movement of the robot and the other two are used for body movement.

Some remote operations can be done with touch screen technology using wireless communication for answering calls, locating and communicating with staff, and operating vehicles and robots. For this purpose RF communication or infrared communication may be used.

A Real-time Application: Controlling Home Appliances using Touch Screen Technology

It is possible to control the electrical appliances at home using touch screen technology. The whole system works by sending input commands from the touch screen panel through the RF communication which are received at the receiver end and control the switching of loads.

At the transmitter end, a touch screen panel is interfaced with the Microcontroller through a touch screen connector. When an area on the panel is touched, the x and y coordinates of that area are sent to the Microcontroller which generates a binary code from the input.

This 4-bit binary data is given to the data pins of the H12E encoder which develops a serial output. This serial output is now sent using an RF module and an antenna.

At the receiver end, the RF module receives the coded serial data, demodulates it and this serial data is given to the H12D decoder. This decoder converts this serial data into parallel data which pertains to the original data sent by the microcontroller at the transmission end. The microcontroller at the receiver end receives this data and accordingly sends a low logic signal to the corresponding optoisolator which in turn switches on the respective TRIAC to allow AC current to the load, and the respective load is switched on

Touch Screen Properties

The main properties of the touchscreen include the following.

• Ball drop test
• Clarity and Brightness
• Mechanical and Mounting
• 4K vs Full-HD
• HID Compatible
• Touchpoints
• Response Time
• Touch Resolution
• Raised Bezel
• Latency / Lag / Touch Response

Advantages

The advantages of touchscreen technology include the following.

• Easy to Clean and Maintain
• Engaging and Interactive
• Self-Service Feature
• Keyboard and Mouse are not required
• Speed and Efficiency
• Mobility and Space
• Durability and Resilience
• Easy User Interface

Disadvantages

The disadvantages of touch screen technology include the following.

• The display of the device has to be large to operate the screen properly
• The display will get dirty
• These are expensive as compared to normal devices
• Indirect sunlight, it is less efficient to read the screen
• Battery life is low due to the big bright screen and uses massive computing power
• Accuracy & Feedback
• Issues on On-screen Keyboard
• Issues due to Sensitivity
• Screen Size
• Accidental Dialing

Applications

The applications of touchscreen technology include the following. Some of the examples of touchscreens like smartphones, a tablet or a computer & a point of sale device.

• All-in-One computer
• Touch screen printer
• Ticket machine
• Arcade game
• Tablet
• ATM
• Car GPS
• Smartphone
• Signature pads
• Camera
• POS machine
• Car stereo
• Medical equipment
• Cash register
• Large interactive screen
• Digital camcorder
• In-flight entertainment screen
• Laptop
• Handheld game console
• E-book
• Grocery self-checkout machine
• Kiosk
• Gas station
• Sewing machine
• Fitness machine
• Electronic whiteboard
• Factory machine

The touch screen supported most of the computers are Acer, HP, Dell, Microsoft, Lenovo, and other PC designers. And also, some high-end Google Chromebooks use touch screens.

Thus, this is all about an overview of touchscreen technology. The main reasons to choose this technology instead of physical buttons by the manufacturers are; these are instinctive, particularly to younger generations of users. By using this technology, the devices can make smaller. The design of these devices is cheaper. In touch screens, different technologies are used to let the operator operate a screen. Some technologies use a finger whereas others use tools such as a stylus. Here is a question for you, Do touch screens use a keyboard?