TOUCH SCREEEN WORKING PRINCIPLE

TOUCH SCREEN PRINCIPLES

Definition:
          
A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus. Touchscreens are common in devices such as game consoles, all-in-one computers, tablet computers, and smartphones.
The touchscreen has two main attributes. First, it enables one to interact directly with what is displayed, rather than indirectly with a pointer controlled by a mouse or touchpad. Secondly, it lets one do so without requiring any intermediate device that would need to be held in the hand (other than a stylus, which is optional for most modern touchscreens). Such displays can be attached to computers, or to networks as terminals. They also play a prominent role in the design of digital appliances such as the personal digital assistant (PDA), satellite navigation devices, mobile phones, and video games.

Surface acoustic wave

Main article: Surface acoustic wave

Surface acoustic wave (SAW) technology uses ultrasonic waves that pass over the touchscreen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Surface wave touchscreen panels can be damaged by outside elements. Contaminants on the surface can also interfere with the functionality of the touchscreen.

Capacitive

Capacitive touchscreen of a mobilePhone

 

Main article: Capacitive sensing

A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO).As the human body is also an electrical conductor, touching the surface of the screen results in a distortion of the screen's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location is then sent to the controller for processing. Unlike a resistive touchscreen, one cannot use a capacitive touchscreen through most types of electrically insulating material, such as gloves; one requires a special capacitive stylus, or a special-application glove with an embroidered patch of conductive thread passing through it and contacting the user's fingertip. This disadvantage especially affects usability in consumer electronics, such as touch tablet PCs and capacitive smartphones in cold weather.

 Surface capacitance

In this basic technology, only one side of the insulator is coated with a conductive layer. A small voltage is applied to the layer, resulting in a uniform electrostatic field. When a conductor, such as a human finger, touches the uncoated surface, a capacitor is dynamically formed. The sensor's controller can determine the location of the touch indirectly from the change in the capacitance as measured from the four corners of the panel. As it has no moving parts, it is moderately durable but has limited resolution, is prone to false signals from parasitic capacitive coupling, and needs calibration during manufacture. It is therefore most often used in simple applications such as industrial controls and kiosks.

 Projected capacitance

Back site of Multitouch Globe create on base of Projected Capacitive Touch (PCT) technology.

Projected Capacitive Touch (PCT) technology is a capacitive technology which permits more accurate and flexible operation. An X-Y grid is formed 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 the grid (comparable to the pixel grid found in many LCD displays) that the conducting layers can be coated with further protective insulating layers, and operate even under screen protectors, or behind weather- and vandal-proof glass. Due to the top layer of a PCT being glass, it is a more robust solution than resistive touch technology. Depending on the implementation, an active or passive stylus can be used instead of or in addition to a finger. This is common with point of sale devices that require signature capture. Gloved fingers may or may not be sensed, depending on the implementation and gain settings. Conductive smudges and similar interference on the panel surface can interfere with the performance. Such conductive smudges come mostly from sticky or sweaty finger tips, especially in high humidity environments. Collected dust, which adheres to the screen due to the moisture from fingertips can also be a problem. There are two types of PCT: Self Capacitance and Mutual Capacitance. A PCT screen consists of an insulator such as glass or foil, coated with a transparent conductor – sensing (Copper, ATO, Nanocarbon or ITO). As the human finger (is also a conductor) touching the surface of the screen results in a distortion of the local electrostatic field, measurable as a change in capacitance.Now PCT used mutual capacitance, which is the more common projected capacitive approach and makes use of the fact that most conductive objects are able to hold a charge if they are very close together. If another conductive object, in this case a finger, bridges the gap, the charge field is interrupted and detected by the controller. All PCT touch screens are made up of an electrode - a matrix of rows and columns. The capacitance can be changed at every individual point on the grid (intersection). It can be measured to accurately determine the exactly touch location. All projected capacitive touch (PCT) solutions have three key features in common: • Sensor as matrix of rows and columns. • Sensor lies behind the touch surface. • Sensor does not use any moving parts.

Dispersive signal technology

Introduced in 2002 by 3M, this system uses sensors to detect the Piezoelectricity in the glass that occurs due to a to
uch. Complex algorithms then interpret this information and provide the actual location of the touch. The technology claims to be unaffected by dust and other outside elements, including scratches. Since there is no need for additional elements on screen, it also claims to provide excellent optical clarity. Also, since mechanical vibrations are used to detect a touch event, any object can be used to generate these events, including fingers and stylus. A downside is that after the initial touch the system cannot detect a motionless finger.

Construction

There are several principal ways to build a touchscreen. The key goals are to recognize one or more fingers touching a display, to interpret the command that this represents, and to communicate the command to the appropriate application.
In the most popular techniques, the capacitive or resistive approach, there are typically four layers:

1. Top polyester coated with a transparent metallic conductive coating on the bottom
2. Adhesive spacer
3. Glass layer coated with a transparent metallic conductive coating on the top
4. Adhesive layer on the backside of the glass for mounting.

When a user touches the surface, the system records the change in the electrical current that flows through the display.
Dispersive-signal
technology which 3M created in 2002, measures the piezoelectric effect — the voltage generated when mechanical force is applied to a material — that occurs chemically when a strengthened glass substrate is touched.
There are two infrared-based approaches. In one, an array of sensors detects a finger touching or almost touching the display, thereby interrupting light beams projected over the screen. In the other, bottom-mounted infrared cameras record screen touches.
In each case, the system determines the in
tended command based on the controls showing on the screen at the time and the location of the touch.

Development

Most touchscreen patents were filed during the 1970s and 1980s and have expired. Touchscreen component manufacturing and product design are no longer encumbered by royalties or legalities with regard to patents and the use of touchscreen-enabled displays is widespread.
The development of multipoint touchscreens facilitated the tracking of more than one finger on the screen; thus, operations that require more than one finger are possible. These devices also allow multiple users to interact with the touchscreen simultaneously.
With the growing use of touchscreens, the marginal cost of touchscreen technology is routinely absorbed into the products that incorporate it and is nearly eliminated. Touchscreens now have proven reliability. Thus, touchscreen displays are found today in airplanes, automobiles, gaming consoles, machine control systems, appliances, and handheld display devices including the Nintendo DS and the later multi-touch enabled iPhones; the touchscreen market for mobile devices is projected to produce US$5 billion in 2009.
The ability to accurately point on the screen itself is also advancing with the emerging graphics tablet/screen hybrids.
TapSense, announced in October 2011, allows touchscreens to distinguish what part of the hand was used for input, such as the fingertip, knuckle and fingernail. This could be used in a variety of ways, for example, to copy and paste, to capitalize letters, to active different drawing modes, and similar.

 

AaKash Tablet Pc Specification


As released on 5 October 2011, the Aakash features an overall size of 190.5 x 118.5 x 15.7 mm with a 180 millimetres (7.1 in) resistive touchscreen,^[20] a weight of 350 grams (12 oz) and using the Android 2.2 operating system with access to the proprietary marketplace Getjar (not the Android Market), developed by DataWind.
The processor runs at 366 MHz; there is a graphics accelerator and HD video coprocessor. The tablet has 256 MB RAM, a micro SD slot with a 2 GB Micro SD card (expandable to 32 GB), two USB ports, a 3.5 mm audio output and input jack, a 2100 mAh battery, Wi-fi capability, a browser developed by DataWind, and an internal cellular and Subscriber Identity Module (SIM) modem. Power consumption is 2 watts, and there is a solar charging option.
The Aakash is designed to support various document (DOC, DOCX, PPT, PPTX, XLS, XLSX, ODT, ODP,PDF), image (PNG, JPG, BMP and GIF), audio (MP3, AAC, AC3, WAV, WMA) and video (MPEG2, MPEG4, AVI, FLV) file formats and includes an application for access to YouTube video content.

Specifications	Aakash	UbiSlate 7+
Price	2,500	2,999
Central processor unit speed	ARM11, 366 MHz	ARM Cortex-A8, 700 MHz
Random-access memory	256 MB	256 MB[25]
Battery	2100 mAh	3200 mAh
Operating system	Android 2.2 Froyo	Android 2.3 Gingerbread
Network	Wi-Fi	Wi-Fi + GPRS phone network
Phone Call	No	yes
Screen	Resistive	Resistive
App Store [26]	GetJar	Android Market
Made in	India	India

will have a micro-SD slot, and a 2 GB micro-SD flash memory card, upgradable to 32 GB, to store user data and programs not run from ROM. In Android 2.3 some applications and data can be moved from the ROM to the memory card.
Memory: ROM size has apparently not been stated by Datawind, but is estimated to be either 256 MB or 2 GB.^[27] Both tablets have graphics processing cards, but the graphics memory size and GPU speed have not been stated .
Google Android Market: Aakash has no SIM card and insufficient processing power to use Google's Android Market, and will instead use the GetJar Marketplace. UbiSlate-7+ also will not have access to Google's Android Market confirmed by Google.
Network: Aakash supports wireless local area network (wireless LAN, Wi-Fi). It does not support GPRS/3G cellular networks. UbiSlate-7+ has GPRS Internet connection, a 2.5 generation Internet connection. Both tablets support an external 3G USB modem.

Browser

Datawind announced that their browser will use data compression technology to speed up data transmission. Compressed data such as ZIP files, JPEG images, MP3 audio, MPEG video will be transmitted at the basic speed, while uncompressed data will transmit typically at speeds up to 6 times faster, depending upon its nature. If and when successfully combined with Server-side web compression, 1G Analog Internet service might actually be able to compete with 2G or 3G digital internet service. Datawind claims that their browser can give up to 30 times faster speeds..... Quick 2 order thz tablet...!

Super Computer NetWork

Google a Busy Beaver
near Mount Hood, Oregon

In a hush-hush project, Google has been building a huge computing center on the banks of the Columbia River in The Dalles, Oregon, to expand it worldwide computing network, which already encompasses an estimated 450,000 servers, more than twice as many as Microsoft's 200,000, reports the New York Times. Using the latest academic research, Google apparently plans to build a network of supercomputers that can process more data, more quickly and less expensively than rivals.

The new Google project, known locally as Project 02, will tap into the region's surplus of fiber optic networking, left over from the dot-com boom. The Dalles city officials have signed confidentiality agreement with Google and will not comment on the project. But typing "Dalles Google" as a Google search query reveals plenty about the project.
Google, Microsoft and Yahoo are spending billions to build out their computing infrastructures to run their search engines and various web-based services, including mail, video and music downloads and e-commerce.

AMAZING

or those who have been paying attention, I've been posting photos taken in Oahu for the last week or so. Most of them have been pretty standard stuff -- what you'd expect to see here. I thought this one might be a little unexpected. This is part of Waikiki at night shot from the water. It was taken during a full moon (which is just out of the shot), so it lit up the clouds that were quickly rushing by that night. It was a pretty awesome night sky. Waikiki may be seen as an overly touristy area, but I actually really love it, especially at night. I love seeing these buildings lit up and reflected in the water, and I love the international mix of people you'll see walking on Kalakaua and the beach.

Google Glasses, lets make the Terminator

Google developed the Terminator glasses look at the village of Oakley HUD (head of the window) (photo below).

It seems that Google, with some style cues from the terminator, will be introducing their latest mobile gadget.  For now, it is defined as the "Terminator" glasses and display feature augmented reality.  This display "increased" will give users a unique view of his or her surroundings, much more in-depth and advanced 2-d ones so that you can see on your smartphone.

Secret Google project showed that in December, the relevant points.

The hearing, originally announced in the New York Times on this article in December. He said: I have been glasses, similar to the prototype with thick glasses, "ordinary people" who are in the final stages. The heads of State and Government, however, offer a computer with a user interface. Coat of arms of the glasses has a number of buttons, but otherwise, it could be confused as normal elements. Not sure about the technology, but it can be a transparent AMOLED display, LCD or how install below:

• In addition, we hear that the device as "Android peripheral"is defined in the Auxin. The source of the US media directly with your IP address through the clouds, even though the "Google goggles" you will not be able to connect to Wi-Fi or low fuel consumption, Bluetooth phone 4.0.
• The use case is augmented reality to be undertaken in Google Web services. User can walk around with information and view connects have emerged-break-style based on preferences and site and Google information.
• So these things can connect to the Internet and have GPS. They can run the version of Android.

According to 9to5google, this gadget will have a processor of 1Ghz , 256MB RAM, 8 GB inbuilt memory, WiFi and also 3G.

If you want to navigate or click, move just the head… Hmm, it will be a little crazy in town.

Now, to find more information. The project, known as Project X, a point on the basis of the heads-up display. Since then different applications for the project.

led camera Flash source, rumors, a few glasses of megapixel front facing augmented reality applications. A screen on the device a very opaque lenses. How is the most interesting part of his head in different directions for different things: the tendency.

Glasses, so you can call directly from your device are the audio input and output. Also, cpu, ram, and storage are all typical hardware, including. A smart phone, but will act as close to home.

Google just as they would with its chromebooks, a pilot program which will do much for your device. Google goggles is literally.

MY FRND HE S NO MORE......!

PLZ WATCH THZ VIDEO