A Seminar Report on

TOUCH SCREEN WITH FEELINGS

Submitted in partial fulfillment of the requirement for the award of degree

of

BACHELOR OF TECHNOLOGY
in
ELECTRONICS AND COMMUNICATION ENGINEERING

Submitted By
K.VINEETH
(17FE1A0446)

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

VIGNAN’S LARA INSTITUTE OF TECHNOLOGY & SCIENCE
(An ISO 9001:2015 Certified, Approved by AICTE, Affiliated to JNTU, KAKINADA)
VADLAMUDI-522213, GUNTUR Dist., ANDHRAPRADESH.
2020- 21
 DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
VIGNAN’S LARA INSTITUTE OF TECHNOLOGY & SCIENCE
(An ISO 9001:2015 Certified, Approved by AICTE, Affiliated to JNTU, KAKINADA)
VADLAMUDI-522213, GUNTUR Dist., ANDHRA PRADESH

CERTIFICATE

This is to certify that seminar entitled “ TOUCH SCREEN WITH FEELINGS ” is a

bonafide work done by K.Vineeth (17FE1A0446), submitted in partial fulfillment of

requirement for award of degree of Bachelor of Technology in Electronics and

Communication Engineering by Jawaharlal Nehru Technological University, Kakinada.

Head of the Department

Mr. Suman,
M.Tech (Ph.D.),
Assistant Professor
 ACKNOWLEDGEMENT

We are most thankful to our parents who stood as pillars of motivation and for the way they
influenced and moulded our lives.

We are more thankful to our chairman Dr. LAVU RATHAIAH who helped us to have a
technical incubation by providing the required infrastructure.

We are very much thankful to our principal Dr. K. PHANEENDRA KUMAR who extended
a timely help at each and every step of our academic career.

We are very thankful to our Head of the department Mr. M.SUMAN an amicable person who
supported us very much and helped to a maximum extent and made this project successful.

Finally, we are thankful to each and every faculty members both technical and non -technical,
friends and all the persons who helped us directly or indirectly in making our project a successful one.

By

K.Vineeth (17FE1A0446)
 CONTENTS

DESCRIPTION PAGE NO
ABSTRACT i
LIST OF FIGURES ii
LIST OF ABBREVIATIONS iii

CHAPTER 1: INTRODUCTION 1-4

1.1 Introduction to Touch Screen with feelings 1
1.2 Touch screen technology 3
1.3 Ordinary Touch screens 4

CHAPTER 2: Tactile Pattern Display(TPaD) 5-8

2.1 Characteristics of TPaD 7
2.2 Tactile Pattern Display(TPaD) Device 8

CHAPTER 3: Construction 9-11

3.1 Bending Element Construction 9
3.2 Driving Electronics 10
3.3 Squeeze Film air bearings 11

CHAPTER 4: 12-17
4.1 Advantages 12
4.2 Disadvantages 13
4.3 Applications 14

CHAPTER 5: CONCLUSION & FUTURE SCOPE 18-19

REFERENCES 20
 ABSTRACT

This seminar includes the theory, design and construction of a haptic display for creating texture

sensations through variations in surface friction. Ultra-sonic frequency, low amplitude

vibrations between two flat plates have been shown tocreate a squeeze film of air between the

two plate surfaces thereby reducing the friction. Here, it is shown that a reduction of friction

will also occur between a human finger and a vibrating plate. Thus, a vibrating plate can serve

as a haptic interface. The amplitude of vibration can also be correlated to the amount of friction

reduction the plate and the finger. Varying the surface friction between the finger and the haptic

interface is a way of indirectly controlling shear forces on the finger during active exploration.

Using finger position and velocity feedback on the display allows for the creation of spatial

texture sensations.
 LIST OF FIGURES
Page
Figure Number Figure Name
Number
1 Stimuli produced in the tactile display 6
2 Sample of virtual textures implemented on the TPaD 7
3 Surface plots of friction coefficient patterns 9
4 piezo bending element and mount 10
5 vibration mode of bending element 11
6 An electro static display 14
7 GraphiGlove 15
8 Flexible tactile display 16
 LIST OF ABBREVIATIONS
S.No. Abbreviation Expansion
1 TPaD Tactile Pattern Display
2 IDT Interdigital Transducers
3 SAW Several Substrate Surfaces
TOUCH SCREEN WITH FEELINGS

CHAPTER 1
1.1: Introduction
In this digital age, our fingers have accomplished to love touch screens.

They provide an easy, emotional way to navigate our devices to make them do our

bidding. But still, our fingers haven’t felt any love in return. All glass screens feel the

same, they take, but as far as the tactile experience goes, they don’t give back. The closest

way to get finger feedback with most touch screens today comes from mechanical

actuators that vibrate the screen when your fingers touch it. You feel a minor vibration,

but nothing more. But think touchscreens could touch you back “your fingers actually

feel what the screen shows”.

The advancement in touch screen technology enhanced a device called

Tactile Pattern Display, or TPaD. It can create the image of texture on an unadorned

piece of glass. The 25-millimeter-diameter prototype takes advantage of the almost high

coefficient of friction between human skin and glass. Glass is remarkably. You could

think of it as being smooth, but the coefficient of friction between glass and your

fingertip is about 1. But when the glass is vibrated ultrasonically, a cushion of air

designs between your finger and its surface. The TPaD’s 1.6-mm-thick glass layer is set

into ultrasonic oscillation by a piezoelectric ceramic disc interested to the glass. The

amplitude of the oscillation can be controlled, reducing the coefficient of friction by up

to a factor of 10. The higher the amplitude of oscillation, the lower the coefficient of

friction.

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TOUCH SCREEN WITH FEELINGS
When you run a finger across the TPaD, you get a very strong tactile

emotion of something being there, like a bump, a dip, or an edge. To create

the feeling that you are rubbing your finger against a file grating. The entire plate

vibrates, so the amount of friction is the equal all over the TPaD’s surface at

any given time. But because the oscillations are restrained as your finger’s

position changes, the device fools you into thinking that there are varying

amounts of friction at different locations. The prototype uses optical sensors to

keep record of your finger’s position. The friction reduction can be switched on

and off so quickly within 4 ms on average that the pitch of virtual bumps or

dips can be made far finer than what a fingertip can discern.

Another technical complication is limiting how much power the

TPaD draws, which is hugely important in mobile devices, where your power

budget is measured in milliwatts. In principle, the TPaD does not need a lot of

power, but in practice, you run into issues like power being dissipated through

things like mountings.

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TOUCH SCREEN WITH FEELINGS
1.2: Touch Screen Technology
A touch screen is an electronic visual display that can detect the presence andlocation of

a touch within the display area. The term generally refers to touch or contact to the

display of the device by a finger or hand. The ability to interact physically with what is

shown on a display (a form of "direct manipulation") typically indicates the presence of

a touch screen.

The touch screen has two main attributes.

 It enables one to interact with what is displayed directly on the screen, where it

is displayed, rather than indirectly with a mouse or touchpad.

 It lets one do so without requiring any intermediate device, again, such as a stylus

that needs to be held in the hand.

Touch screens enable people to use computers instantly, without anytraining.

Touch screens eliminate keyboards and mice, which many find intimidatingand

cumbersome to use.

Touch screens provide fast access to any and all types of digital media, withno text-

bound interface getting in the way.

Touch screens ensure that no space - on the desktop or elsewhere - is wasted,as the

input device is completely integrated in to the monitors.

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TOUCH SCREEN WITH FEELINGS
1.3: Ordinary Touch Screens:
Touch screen is a misnomer. Ordinary touch screens can detect the presenceand location

of a touch. It contains three main components, those are

Touch Sensor

Controller

Software Drive

Touch Screen Sensor: It is a clear glass panel with a touch responsive surface.The

touch sensor/panel is placed over a display screen so that the responsive area of the panel

covers the viewable area of the video screen.

Controller: I t is a small PC card that connects between the touch sensor andthe PC.

It takes information from the touch sensor and translates it into information that PC can

understand.

Software Driver: The driver is a software update for the PC system that allowsthe

touch screen and computer to work together. It tells the computer's operating system how

to interpret the touch event information that is sent from the controller.

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TOUCH SCREEN WITH FEELINGS
CHAPTER 2
Tactile Pattern Display(TPaD)

The T-PaD is an ultrasonic device which builds on several previous efforts.

Using a vibrating Langevin-type piezoelectric actuator to create a standing wave on a

flexural beam. During finger exploration of the beam a reduction in friction was observed

when the beam was actuated. This reduction in frictionwas used to mask surface features

from the user. the reduction in friction was caused by a squeeze film of air under the

finger pad. In ultrasonic tactile displays used interdigital transducers (IDT) to create

surface acoustic waves (SAW’s) on several substrate surfaces. The SAW’s generated

were in the MHzrange and were shown to reduce surface friction.

The reduction in friction was believed to be the result of “decreased contact

time between the balls and the substrate,” an air squeeze film between the ballsand the

substrate, and “parallel movement of the wave crest.”

TPaD is a novel technology, it creates texture sensations through variations

in surface friction. TPaD Creates the illusion of texture on an unadorned pieceof glass.

The coefficient of friction between glass & fingertip is about 1mm. Ithas no visible or

audio texture.

TPaD uses vibration to create variable friction areas on a touch screen. It

provides a layer of air between your finger & the screen which reduce the friction. The

System tracks finger position & turns the vibration on & off.

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TOUCH SCREEN WITH FEELINGS

(A)

(B)
Figure 1: Examples of stimuli produced in the tactile display: (A) The 2-Dpresentation
of the palm, (B) and the 3-D presentation.

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TOUCH SCREEN WITH FEELINGS
2.1: Characteristics of TPaD
In the Tactile Pattern Display characteristics includes the rough spot, sticky circle, rough,

file grating, low profile Edge and smooth bumps. These are the sample of virtual textures

implemented on the TPaD.

Color used to indicate friction level of Tactile Pattern Display(TPaD). Darker colors

represent the higher coefficients of friction. Whereas lighter colors represent the lower

coefficients of friction which is shown in below figure.

Figure2: sample of virtual textures implemented on the TPaD.

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TOUCH SCREEN WITH FEELINGS
2.2: Tactile Pattern Display (TPaD) Device

The novelty of our T-PaD device is derived from not only the innovative bending element

design but also the ability to display virtual texture sensations.By controlling the surface

friction, we can therefore control the shear forces on the finger interacting with the

display. Knowing the location of the finger on the display allows for the creation of shear

force patterns on the display , i.e., the coefficient of friction on the surface is a function of

the finger location.These patterns are perceived by the user as texture sensations. For

example, a ”file grating” texture, is created by setting the coefficient of friction equal to

a square wave function of the x position of the finger. The texture sensations shown

represent four of many possible spatial shear force patterns.

In designing the T-PaD we felt it was imperative to fulfill the four following criteria:

Slim Design, High Surface Friction, Inaudible and Controllable Friction. Since this

device only reduces friction, it is desirable to start with a surface of relatively high

surface friction. It is also important for all parts of the device to resonate outside of the

audible range. Finally, a mapping betweenthe excitation voltage and the level of friction

reduction (oscillation amplitude)must be determined for successful friction control.

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TOUCH SCREEN WITH FEELINGS

CHAPTER 3
3.Construction:
3.1: Bending Element Construction

The Piezoelectric Bending Element Haptic Display presented in this paper and modeled

and comprises a 25 mm diameter, 1 mm thick piezo ceramic disk epoxied to a glass disk

of equal diameter and 1.59 mm thickness. The piezo-ceramic disks used were identical

to those used by Weis endanger. However, the steel support layer was replaced with a

thicker glass layer. A thicker glass is beneficial in several ways. A glass interface has a

higher coefficient of friction than steel, allowing for a broader range of shear forces. The

thicker support layer of glass increases the resonant frequency, ensuring operation out of

the audible range, while not sacrificing amplitude. Thebending element has a total height

of only 2.59 mm and the mounting rings canhave a height less than 5 mm. The surface

friction with the finger is noticeablyincreased by using glass. Audible noise has been

eliminated, and a correlationbetween excitation voltage and surface friction has been

developed.

Figure 3: Surface plots of friction coefficient patterns.

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TOUCH SCREEN WITH FEELINGS

The surface friction with the finger is noticeably increased by using glass.Audible noise

has been eliminated , and a correlation between excitation voltage and surface friction

has been developed.

3.2: Driving Electronics

The device is driven at resonance, approximately 33 kHz, with an amplituderanging

from 0 to 40 Volts peak to peak. A 33 kHz, 10 Volt peak to peak signal is generated

by a signal generator and scaled to a computer-controlledamplitude using an analog

multiplier chip (AD633AN). The signal is amplified and then stepped up by a 70V

line transformer. In a computer- generated output level of 5 volts DC, corresponding

to a 33KHz signal amplitude at the piezo of 40 V peak-to- peak, resulted in

approximately a ten-fold reduction of the coefficient of friction. The amplitude of the

33KHzsignal can be modulated either temporally or with respect to finger position to

produce interesting sensations across the surface of the disk.

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TOUCH SCREEN WITH FEELINGS

Figure 5: Vibration mode of bending element

3.3: Squeeze Film Air Bearings

The air squeeze film effect is a consequence of the relationship between air’s viscous

and compressibility effects. The presence of an air squeeze film between “parallel,

coaxial, flat disks with relative motion imposed betweenthe surfaces.” Given a high

enough frequency of relative motion and a smallgap distance (relative to the size of

the plate), viscous forces in the air between the plates will restrict air flow out of the

plates while compressibility effects will result in an average pressure between the

platesabove atmospheric. This effect using a normalized general Reynolds equation,

the governing equation for isothermal flow in thin gas films. The squeeze number, σ,

used by contains information on the relationship between the viscous and

compressibility effects of the air. A large squeeze number (σ > 10) represents an air

film which acts very much like a nonlinear spring.

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TOUCH SCREEN WITH FEELINGS

CHAPTER 4
4.1: Advantages:

Tactile feedback : Tactile feedback (also known as haptic feedback) is whathappens

when high vibration patterns and waves are used to transmit information to a user or

operator of an electronic device. “Tactile” means “to touch,” which is appropriate here,

considering many electronics and other products today are designed to relay information

to their users via touch. Thus,many everyday products are now being built with touch

interfaces and displays.

They are also highly desired by users because they can be customized to individual

preferences, which is a huge improvement on the old way of doingthings. Also, tactile

feedback devices benefit companies by being cheaper to produce than audio feedback

ones. With tactile feedback, both customers and companies benefit.

Using tactile feedback also improves on the performance of those using the devices

that include it.

Can be used with projectors / LCD TV’s :

Tactile Pattern Displays are used with projectors, which provides spatially distributed

tactile shape display on a single fingertip with a single-fingered kinesthetic display and

verified its usability. The tactile display unit is embedded into a stylus-like body and the

performance of the haptic stylus.

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TOUCH SCREEN WITH FEELINGS
Many more advantages included in Tactile Pattern Display are listed below

 User Friendly

 High accuracy results in seamless user experience

 Ability to distinguish between parts of the human body

 Secure to work in high traffic environment

 Large content suite & cost-effective

 Suitable for any commercial environment

 The perfect advertising medium.

4.2: Disadvantages :

High Power Consumption :

The development of a large area tactile interface based on squeeze film effect is

challenging. One main issue is the power consumption. Indeed, the dissipated power

converts to heat which increases the temperature of the touchsurface making the user

uncomfortable. Moreover, the heat also changes the resonance frequency of the plate,

reducing the vibration amplitude and furtherdegrading the perception of tactile feedback.

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TOUCH SCREEN WITH FEELINGS
4.3: Applications

 For Blinds :

Figure 6: An electro static haptic display

An electrostatic haptic display can be used for blinds. This technology modulates the

friction between a user’s fingertip and a touchscreen surface to create different tactile

sensations when the finger explores the touch screen. This functionality enables the user

to see and feel digital content simultaneously, leading to improved usability and user

experiences.

Electrostatic friction displays require only electrical components and provide uniform

friction over the screen. This tactile feedback technology not only allows easy and

lightweight integration into touch screen devices but also provides dynamic, rich and

satisfactory user interfaces.

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TOUCH SCREEN WITH FEELINGS

 GraphiGlove :

Figure 7 : GraphiGlove

GraphiGlove is a tactile glove which is used for computer graphics. A data glove

is an interactive device, resembling a glove worn on the hand, which facilitates tactile

sensing and fine-motion control in robotics and virtual reality. Data gloves are one of

several types of electromechanical devices usedin haptics applications.

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TOUCH SCREEN WITH FEELINGS

 Flexible Tactile display :

Figure 8 : Flexible tactile display

Flexible tactile display is a soft tactile display , which is made up of electro

active polymer. The display can deliver precise tactile and thermal stimuli on curved

body parts. The tactile array provides high actuation forces and actuation amplitude.

Simulated objects are discriminated with an accuracy comparable to real objects.

Thus, to improve the quality of teleoperation , there is a high demand for flexible

devices that are capable of matching the skins curvature while delivering multimodal

haptic information to the operator.

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TOUCH SCREEN WITH FEELINGS

 Public & information displays

 Retail & restaurant system

 Control & automation system

 Used as navigation aid

 Computer based training

 Virtual reality keyboard

 Assistive technology

 Tactile display cloth

 Advertisement

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TOUCH SCREEN WITH FEELINGS

CHAPTER 5
Conclusion:
Ability of a piezoelectric bending element to perform the function of a TactilePattern

Display(TPaD). The TPaD has a broad range of controllable friction levels. Texture

sensations are created by both spatial shear force patterns and velocity dependent shear

force patterns on the display .

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TOUCH SCREEN WITH FEELINGS
Future Scope
Future work can be done to reduce the power consumption . Then only it canbe used in

mobile devices which works in mW power range. Tactile pattern displays having much

larger surface area.

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REFERENCES
 http://efymagonline.com

 Uma Gupta ”Take a tour to a world virtually real” in LFY magazine,issue

jan,01,2006

 J. Edward Colgate ”Tactile Pattern

Display(26012/27004/27005/27025)”

 http://www.wikepedia.org

 http://touchmagixmedia.com

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