A touch screen is an electronic visual display that can detect the presence and location of a touch within the display area.
Touchscreens are common in devices such as game consoles, all-in-one computers, tablet computers, and smartphones.
The first touch screen was a capacitive touch screen developed by E.A. Johnson at the Royal Radar Establishment, Malvern, UK.
How do touch-screen monitors know where you're touching?
There are three basic systems that are used to recognize a person's touch:
· Resistive
· Capacitive
· Surface acoustic wave
The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These two layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole setup. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the computer. Once the coordinates are known, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or a drag.
In the capacitive system, a layer that stores electrical charge is placed on the glass panel of the monitor. When a user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each corner, exactly where the touch event took place and then relays that information to the touch-screen driver software. One advantage that the capacitive system has over the resistive system is that it transmits almost 90 percent of the light from the monitor, whereas the resistive system only transmits about 75 percent. This gives the capacitive system a much clearer picture than the resistive system.
On the monitor of a surface acoustic wave system, two transducers (one receiving and one sending) are placed along the x and y axes of the monitor's glass plate. Also placed on the glass are reflectors -- they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100-percent light throughput and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics (both other systems have significant degradation in clarity).
Another area in which the systems differ is in which stimuli will register as a touch event. A resistive system registers a touch as long as the two layers make contact, which means that it doesn't matter if you touch it with your finger or a rubber ball. A capacitive system, on the other hand, must have a conductive input, usually your finger, in order to register a touch. The surface acoustic wave system works much like the resistive system, allowing a touch with almost any object -- except hard and small objects like a pen tip.
Flat surface acts as a touch screen
The device uses an infra-red touch sensing system that transforms a projected image into a virtual 10-inch touch screen. It allows users to interact with multimedia content and applications by touching the image, which can be projected onto any flat surface.
. The system creates bright, high-quality WVGA resolution video images ,projection . Use of a Class 1 safety laser makes the HPL system eye safe.
. Light Touch has 2GB of onboard Flash memory and a Micro SD card slot that supports up to 32GB. The device can be battery operated with a run-time of 2 hours or wall powered for continuous use. Light Touch runs Adobe Flash Lite 3.1, which provides access to a large developer community and enables rapid development of applications such as those that provide interactive wall projections in the home and in retail spaces.
The Age Of Touchscreen Is Soon To Be Over
The best and the most common technology we have So far is the touchscreen technology. no matter if it’s a smartphone or a tablet computer, touchscreen is the main feature you will find in any of those gadgets. but now it seems like the touchscreen will soon be taken over with the touchless technology. this was proved with Microsoft releasing their kinect technology. but no one ever thought that this would be big enough to compete with the touchscreen technology. but according to the latest news, the opinions are beginning to change.
According to the BBC, XTR3D, an Israeli company is now planning to launch smartphones and tv’s with a touchless technology. with this new technology people will be able to change channels of their TV by just making a gesture with the hand without using any kind of remote controls. According to a XTR3D spokesperson, XTR3D’s technology has all the advantages of a 3D camera – it can work in broad daylight, is much cheaper and uses a lot less power. It can be installed on any consumer electronics device. and the best part is this is not just a research, the company is expecting to release the first motion control smartphone to the market, early next year.
HP's Touchless touchscreen wall
About a year ago, HP began working on a ginormous touchscreen display for their PR firm’s Manhattan offices. The resulting product, called the Wall of Touch, was such a hit that it has found its way into the workplaces of other select clients, with more on the way. Ironically, despite its name, one of the things that makes the Wall unique is that users don’t have to actually touch it.
The Wall of Touch is made up of as many as nine 43 to 46-inch, 1080p panels. HP decided not to go with one big panel, as it would require rear projection and a translucent screen material that would compromise resolution. The Wall is driven by an HP Z800 workstation, essentially making it a huge HP TouchSmart computer. Built-in optical cameras and a magnetic strip detect when users are nearing it, thus the lack of needing to actually touch the screen. If users can’t reach the corners, it still works with a mouse or keyboard.
Versions of the Wall are currently in use at the headquarters of the National Basketball Association, as well as the Continental Airlines counter in the Houston airport.
Faster measurements also have the benefit of reducing overall system power. The infrared LED is the biggest contributor to a proximity system’s power budget. Minimizing the time that the LED needs to remain on reduces the overall system power consumption. With 15 dynamically adjustable LED drive settings, the LED drive strength can be adjusted based on the ambient infrared conditions, thereby saving power and leading to a more energy-efficient design.
The LED no longer must be set at a power-hungry maximum setting. Highly sensitive photodiodes also enable the sensor to operate behind very dark glass so that the electronics can remain hidden to the human eye, resulting in cleaner, sleeker industrial designs.
Triple the LEDs, triple the innovation
While single-LED proximity systems are driving today’s market, the future is geared toward multi-LED proximity sensor systems enabling unique innovations in user interfaces. Two-LED infrared systems enable slide and select gestures for use in applications such as page turning in e-books, volume selection in home audio equipment, or scrolling in tablet PCs. Three-LED proximity systems can be used for 3D positional calculation and multi-axis gesturing. These three-LED systems can be used for touchless UI navigation such as icon or photo selection, zooming-in and out in mapping applications, or even game controls.
Other, more exciting applications for two- and three-LED proximity systems are limited only by the designer’s imagination. Just as capacitive touchscreens ushered in a new era of user interfaces, touchless gesturing technology will similarly change how end users interact with electronics products. Two- and three-LED infrared proximity sensor solutions are well suited as touchless-gesturing solutions in these systems.
Touchless benefits: health, safety and convenience
A valid challenge to touchless interfaces is why they should be implemented at all.
Infrared systems are not going to replace existing systems, but instead they are going to augment the user experience. No longer are “computers” relegated to use in the home study or on an office desk. These days people travel everywhere with their smart handsets, personal media players, e-books and tablet PCs.
Coffee shops, restaurants, gyms, bus stops, plane terminals and even lavatories are fair usage environments for this new generation of embedded electronics. In such diverse operating environments, users’ hands are sometimes occupied, dirty, sweaty, or covered in food -- all conditions not conducive to touchscreen operation. If a customer is reading an e-book at the gym while on a treadmill and wants to turn a page, it would be a much easier to swipe across the device with a touchless gesture to turn the page rather than physically contacting a touchscreen or hunting down a small button.
Being able to control a device without having to look at it has additional benefits. For example, a touchless interface can allow an automobile driver to safely start/end a call or adjust volume with the touchless swipe of a hand without having to navigate through a complicated instrument cluster to find control buttons. Not all devices have or need complex graphical displays with touchscreens either, and for such devices a touchless interface can provide an innovative and differentiated approach for operation.
