Touchscreen Technology Presentation

8/3/2019 Touchscreen Technology Presentation

http://slidepdf.com/reader/full/touchscreen-technology-presentation 1/25

1



WHAT IS TO BE EXPLAINED..

INTRODUCTION TO THEINTRODUCTION TO THE

TECHNOLOGYTECHNOLOGY

HOW IT WORKS ?HOW IT WORKS ?

TOUCH SCREEN DIVERSITYTOUCH SCREEN DIVERSITY

CONTROLERS USEDCONTROLERS USED

APPLICATIONSAPPLICATIONS

CONCLUSIONCONCLUSION

2



3

INTRODUCING THE TECHNOLOGY

A touch screen is an input device that allows users tooperate a PC by simply touching the display screen.

The display screen has a sensitive glass overlay placed on

it and we could give the desired input by touching it.

A touch screen is based on CRT (Cathode Ray Tube)technology, that accepts direct onscreen input.

The ability for direct onscreen input is facilitated by anexternal (light pen) or an internal device (touch overlayand controller) ..



4

HOW DOES A TOUCHSCREEN WORK?

Main touch screen components:Main touch screen components:

Touch sensor Touch sensor Controller Controller

Software driver Software driver



5

TOUCH SENSOR

A touch screen sensor is a clear glass panel with aA touch screen sensor is a clear glass panel with atouch responsive surface which is placed over atouch responsive surface which is placed over adisplay screen so that the responsive area of thedisplay screen so that the responsive area of the

panel covers the viewable area of the display panel covers the viewable area of the displayscreen.screen.

The sensor generally has an electrical current or The sensor generally has an electrical current or

signal going through it and touching the screensignal going through it and touching the screencauses a voltage or signal change. This voltagecauses a voltage or signal change. This voltagechange is used to determine the location of thechange is used to determine the location of thetouch to the screentouch to the screen



6



7

CONTROLLER

The controller is a

small PC card that

connects between the

touch sensor and the

PC. It takes

information from the

touch sensor and

translates it into

information that PC

can understand.



8

SOFTWARE DRIVER

The driver is a software that allows the touchThe driver is a software that allows the touch

screen and computer to work together. It tells thescreen and computer to work together. It tells the

operating system how to interpret the touch eventoperating system how to interpret the touch eventinformation that is sent from the controller.information that is sent from the controller.

Most touch screen drivers today are a mouseMost touch screen drivers today are a mouse--

emulation type driver. This makes touching theemulation type driver. This makes touching the

screen the same as clicking your mouse at thescreen the same as clicking your mouse at the

same location on the screen.same location on the screen.



9



10

TOUCH SCREEN DIVERSITY

Resistive Touch screenResistive Touch screen

Surface wave Touch screenSurface wave Touch screen

Capacitive Touch screenCapacitive Touch screen

*Surface capacitive*Surface capacitive

*Projected capacitive*Projected capacitive Near Field Imaging Touch screenNear Field Imaging Touch screen

Infrared Touch screenInfrared Touch screen



11

RESISTIVE TOUCH SCREEN

1.1. Polyester Film .Polyester Film .

2.2. Top Resistive Layer.Top Resistive Layer.

3.3. Conductive TransparentMetal Coating.Conductive TransparentMetal Coating.

4.4. Bottom Resistive Layer .Bottom Resistive Layer .

5.5. Insulating Dots .Insulating Dots .

6.6. Glass SubstrateGlass Substrate



12

Continued«

Resistive touch screen monitor is composed of a flexibletop layer and a rigid bottom layer separated by insulating

dots, attached to a touch screen controller.

The inside surface of each of the two layers is coated with

a transparent metal oxide coating Pressing the flexible top sheet creates electrical contact

between the resistive layers, producing a switch closing in

the circuit.

The controller gets the alternating voltages between theThe controller gets the alternating voltages between the

two layers and converts them into the digital X and Ytwo layers and converts them into the digital X and Y

coordinates of the activated area.coordinates of the activated area.



13

VS20UA CONTROLLER

Supply VoltageSupply Voltage

5.0V5.0V DCDC

MaximumMaximum

CurrentCurrent

20mA (Pick)20mA (Pick)

ResolutionResolution

1212--bit bit



14

SURFACE WAVE TECHNOLOGY It has a transmitting and receiving transducers for bothIt has a transmitting and receiving transducers for both

the X and Y axes.the X and Y axes.

The touchscreen controller sends a 5 MHz electricalThe touchscreen controller sends a 5 MHz electricalsignal to the transmitting transducer, which converts thesignal to the transmitting transducer, which converts the

signal into ultrasonic waves within the glass.signal into ultrasonic waves within the glass.



15

Continued« These waves are directed across the front surface of theThese waves are directed across the front surface of the

touchscreen by an array of reflectors.touchscreen by an array of reflectors.

Reflectors on the opposite side gather and direct theReflectors on the opposite side gather and direct thewaves to the receiving transducer, which reconverts themwaves to the receiving transducer, which reconverts them

into an electrical signalinto an electrical signal² ²a digital map of thea digital map of thetouchscreentouchscreen

When you touch the screen, you absorb a portion of When you touch the screen, you absorb a portion of the wave traveling across it. The received signal isthe wave traveling across it. The received signal isthen compared to the stored digital map, the changethen compared to the stored digital map, the changerecognized, and a coordinate calculated. . Therecognized, and a coordinate calculated. . Thedigitized coordinates are transmitted to the computer digitized coordinates are transmitted to the computer for processing.for processing.



16

2701RSU CONTROLLER

VoltazeVoltaze

+5 VDC+5 VDC

Baud RateBaud Rate

9600 (default) and 192009600 (default) and 19200

Touch ResolutionTouch Resolution

12bit, size independent12bit, size independent

Conversion TimeConversion Time

10 ms per coordinate set10 ms per coordinate set



17

CAPACITIVE TOUCH SCREENS

Surface Capacitive It has a an uniform conductive coating on a glassIt has a an uniform conductive coating on a glass

panel. panel.

During operation, electrodes around the panel'sDuring operation, electrodes around the panel'sedge evenly distribute a low voltage across theedge evenly distribute a low voltage across theconductive layer & creates an uniform electricconductive layer & creates an uniform electricfield.field.

A finger touch draws current from each corner.A finger touch draws current from each corner. Then the controller measures the ratio of theThen the controller measures the ratio of the

current flow from the corners and calculates thecurrent flow from the corners and calculates thetouch locationtouch location



18



19

5000 RSU SERIAL CONTROLLER

Supply Voltage :Supply Voltage :

+5 V DC or +12V+5 V DC or +12V

Baud RateBaud Rate

9600 (default) and 192009600 (default) and 19200

Touch ResolutionTouch Resolution

12bit, size independent.12bit, size independent.

Conversion TimeConversion Time

Approximately 15 ms per Approximately 15 ms per coordinate setcoordinate set



20

Projected Capacitive

Touch screen3layers:3layers:--front andfront and

back protective glass back protective glass

provides optical and provides optical andstrength enhancementstrength enhancement

options & middleoptions & middle

layer consists of alayer consists of alaminated sensor gridlaminated sensor grid

of microof micro--fine wiresfine wires



21

Continued« During a touch,During a touch,

capacitance formscapacitance forms between the finger between the finger and the sensor and the sensor grid.grid.

The embeddedThe embeddedserial controller inserial controller inthe touch screenthe touch screencalculates touchcalculates touch

locationlocationcoordinates andcoordinates andtransmits them totransmits them tothe computer for the computer for processing. processing.



22

APPLICATIONS..

Public Information Displays:::Tourism displays, Trade show display

Customer Self-Services:::Stores, Restaurants, ATMs, Airline ticketterminals and Transportation hubs.

More uses...Digital jukeboxes, Computerized gaming, StudentRegistration systems,Multimedia softwares ,Scientific applications etc.



23

Pros & Cons

Direct pointing to theDirect pointing to the

objects.objects.

FastFast

Finger or pen is usableFinger or pen is usable(No cable required)(No cable required)

No keyboard necessary No keyboard necessary

Suited to: novices,Suited to: novices,application for application for

information retrieval etcinformation retrieval etc

Low precision byLow precision by

using finger using finger

User has to sit or standUser has to sit or stand

closer to the screencloser to the screen The screen may beThe screen may be

covered more by usingcovered more by using

handhand

No direct activation to No direct activation to

the selected functionthe selected function



24

CLOSING THOUGHTS

Though the touch screen technologyThough the touch screen technology

contains some limitations it¶s very user contains some limitations it¶s very user

friendly, fast, accurate, easy for the novicesfriendly, fast, accurate, easy for the novices

& fun to operate. It has been widely& fun to operate. It has been widely

accepted. And now by just modifying aaccepted. And now by just modifying a

little it can replace the mouse and key boardlittle it can replace the mouse and key board

completely in near future.completely in near future.



25

Touchscreen Technology Presentation

Documents

Transcript of Touchscreen Technology Presentation