Oriental institute of science and technology

Touch Screen

Submitted by

Deepansh Agrawal

Abstract

My seminar report is based on the technology of touch screen. We see its use in mobiles, in ATM, in computers etc. The wide use of it makes it a most important technology to be discussed and also to understand it. In my seminar report I have include the working as well as applications and principles of it.

Index

• Introduction • Definition& Types • Components• Description

– Resistive touch screen– Surface wave touch screen.– Capacitive touch screen

Introduction

• We are all aware of touchscreen technology .• We have seen its use in ATM ,Cellphone, public kiosk

etc.• This technology is based on GUI(graphical user

interphase).• “They’re all the rage, they are the buzzword, they are

probably the hottest thing in technological cosmos right now!”

Definition and Types

• A touch screen is a computer display screen that is also an input device. The screens are sensitive to pressure; a user interacts with the computer by touching pictures or words on the screen.

• There are three types of touchscreens a) Resistive touchscreen.b) Capacitive touchscreen. c) Surface touchscreen .

Resistive Touchscreen

• A resistive touch screen panel is coated with a thin metallic electrically conductive and resistive layer that causes a change in the electrical current which is registered as touch event and sent to the controller for processing .

• Advantages •Resistive touchscreen technology works well with almost any stylus like object. •Costs are relatively low when compared with active touchscreen technologies•Resistive touchscreen technology can be made to support multi-touch input

Disadvantages • Low clarity•Less reliability •Bad sensitivity

Capacitive touchscreen • A capacitive touch screen panel is coated with a material that stores electrical charges.

When the panel is touched, a small amount of charge is drawn to the point of contact. Circuits located at each corner of the panel measure the charge and send the information to the controller for processing.

Advantages •Since capacitive screens only respond to materials which are conductive , they can be cleaned with cloths without accidental command input. Resistive touchscreen cannot.•Capacitive touchscreen are more responsive than resistive touchscreen.

•Disadvantages•Capacitive touch screens are more expensive to manufacture and offer a lesser degree of accuracy than resistive touch screens.•Capacitive touch screens cannot be used with gloves, and can fail to sense correctly with even a small amount of water.

Surface wave touchscreen

• Surface wave technology uses ultrasonic waves that pass over the touch screen 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.

•Advantages •The surface wave technology had high touch resolution as well as highest image clarity and is better than other two types of touch screens.

•Disadvantages •It must be touched by finger, gloved hand, or soft-tip stylus, Something, hard like a pen won't work. Not completely sealable, can be affected by large amounts of dirt, dust, etc.

Application

• It uses in mobiles as input screen .• Uses in ATM .• Uses in public kiosk.• Uses in satellites in some portable devices .

Thank u