Seminar Topic Touch Screen Technologyx - 123SeminarsOnly

testybelchMechanics

Nov 14, 2013 (3 years and 9 months ago)

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INDEX



Ser No


Contents


Page No



01


Abstract


02


02


Introduction


02


03


History


03


04


Application in Electronic components


06


05


Infrared


15


06


Optical imaging


15


07


Dispersive Signal Technology


16


08


Acoustic Pulse
Recognition


16


09


Ergonomics and usage


18


10


Conclusion


21


11


Referance


21

1


INDE


Abstract



1.

Touch screen interfaces are becoming increasingly common
among portable and desktop computing systems. The global
production of touch screen
systems has increased exponentially in
the recent years.

2.

In this technical paper, the history and evolution of touch
screen technology over the years have discussed. Moreover, the
various types of touch screens and technologies behind that are also
add
ressed. The comparison of various types will give one a technical
edge over selecting from a wide array of touch screen interface
devices.


Introduction


3.

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

all
-
in
-
one computers
,

tablet computers
, and smartphones.

4.

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. 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
2


assistant

(PDA),

satellite navigation

devices,

mobile phones
,
and

video games
.


History of Touch Screen Technology

1960s

5.

Historians consider the first touch screen to be a capacitive
touch screen invented by E.A. Johnson at
the Royal Radar
Establishment, Malvern, UK, around 1965
-

1967. The inventor
published a full description of touch screen technology for air traffic
control in an article published in 1968.

1970s

6.

In 1971, a "touch sensor" was developed by Doctor Sam Hur
st
(founder of Elographics) while he was an instructor at the University
of Kentucky. This sensor called the "Elograph" was patented by The
University of Kentucky Research Foundation. The "Elograph" was not
transparent like modern touch screens, however, i
t was a significant
milestone in touch screen technology. The Elograph was selected by
Industrial Research as one of the 100 Most Significant New Technical
Products of the Year 1973.

7.

In 1974, the first true touch screen incorporating a transparent
surfa
ce came on the scene developed by Sam Hurst and Elographics.
In 1977, Elographics developed and patented a resistive touch screen
technology, the most popular touch screen technology in use today.

8.

In 1977, Siemens Corporation financed an effort by Elogr
aphics
to produce the first curved glass touch sensor interface, which
became the first device to have the name "touch screen" attached to
3


it. On February 24, 1994, the company officially changed its name
from E
lographics to Elo TouchSystems.

1980s

9.

In
1983, the computer manufacturing company, Hewlett
-
Packard introduced the HP
-
150, a home computer with touch screen
technology. The HP
-
150 had a built in grid of infrared beams across
the front of the monitor which detected finger movements.
However, the in
frared sensors would collect dust and require
frequent cleanings.

1990s

10.

The nineties introduced smart phones and handhelds with
touch screen technology. In 1993, Apple released the Newton PDA,
equipped with handwriting recognition; and IBM released the

first
smart phone called Simon, which featured a calendar, note pad, and
fax function, and a touch screen interface that allowed users to dial
phone numbers. In 1996, Palm entered the PDA market and
advanced touch screen technology with its Pilot series.

2000s

11.

In 2002, Microsoft introduced the Windows XP Tablet edition
and started its entry into touch technology. However, you could say
that the increase in the popularity of touch screen smart phones
defined the 2000s. In 2007, Apple introduced the king

of smart
phones, the

iPhone
, with nothing but touch screen technology.

12.

Touch
-
screen monitors have become more and more
commonplace as their price has steadily dropped over the

past
4


decade. There are

sevral

basic systems that are used to recognize a
person's touch:

13.

In

electrical engineering
,

resistive touchscreens

are

touch
-
sensitive

computer displays

composed of two flexible sheets coated
with a resistive material a
nd separated by an air gap or

microdots
.
When contact is made to the surface of the touchscreen, the two
sheets are pressed together. On these two sheets there are
horizontal and vertical
lines that when pushed together, register the
precise location of the touch. Because the touchscreen senses input
from contact with nearly any object (finger, stylus/pen, palm)
resistive touchscreens are a type of "passive" technology.

14

For example,
during operation of a four
-
wire touchscreen, a
uniform, unidirectional voltage gradient is applied to the first sheet.
When the two sheets are pressed together, the second sheet
measures the voltage as distance along the first sheet, providing the
X coordi
nate. When this contact coordinate has been acquired, the
uniform voltage

gradient

is applied to the second sheet to ascertain
the Y coordinate. These operations occur within a few
millise
conds,


registering the exact touch location as contact is made.

15.

Resistive touchscreens typically have high resolution (4096 x
4096 DPI or higher), providing accurate touch control. Because the
touchscreen responds to pressure on its surface, contact c
an be
made with a finger or any other pointing device.

16.

SAWs were first explained in 1885 by

Lord Rayleigh
, who
described the surface acoustic mode of propagation and predicte
d its
properties in his classic paper.


Named after their
discoverer,

Rayleigh waves

have a

longitudinal

and a vertical shear
component that can couple with any media in contact with the
surface. This coupling strongly affects the amplitude and velocity of
the wave, allowing SAW sensors to directly sense mass and
mechanical properties.



5


SAW Devi
ces


17.

SAW devices use SAW wave in electronic components to
provide a number of different functions, including as delay lines,
filters, correlators and DC to DC converters.


Application in electronic components


18.

This kind of

wave

is commonly used in devices called

SAW
devices

in

electronic

circuits
. SAW devices are used
as

filters
,

oscillators

and

transformers
, devices that are based on
the

transduction

of acoustic waves. The transduction from electric
energy to mechanical energy (in the form of SAWs) is accomplished
by the use of

piezoelectric

materials.



Schematic picture of a typical SAW device design
.

19.

Electronic devices employing SAWs normally use one or
more

interdigital

transducers

(IDTs) to convert acoustic waves to
electrical signals and vice versa by exploiting the piezoelectric effect
of certain materials (
quartz
,

lithium niobate
,

lithium
tantalate
,

lanthanum gallium silicate
, etc.).


These devices are
fabricated by

photolithography
, the process used in the manufacture
of silicon

integrated circuits
.

6


20.

SAW filters

are now used in

mobile telephones
, and provide
significant advantages in performance, cost, and size over other filter
technologies such as
quartz crystals

(based on bulk waves),

LC filters
,
and

waveguide

filters.

21.

Much research
has been done in the last 20 years in the area
of

surface acoustic wave sensors
.
[3]

Sensor applications include all
areas of sensing (such as chemical, optical,
thermal,

pressure
,

acceleration
,

torque

and biological). SAW sensors
have seen relatively modest commercial success to date, but are
commonly commercially available for some applications such
as

touchscreen

displays.

SAW device applications in radio and television



22.

T
his is a typical photo of SAW (surface acoustic wave) resonator
commonly used in garage door opener remote control and rf
modules.



7


23.

A

typical inner photo of fixed frequency RF remote control
(315mhz,433mhz,etc.) which uses SAW (surface acoustic wave
)
resonator to stabilize transmitting frequency.

24.

SAW resonators are often used in radio transmitters where
tunability is not required. They are often used in applications such as

garage door opener

remote controls, short range radio frequency
links for computer peripherals, and other devices
where

channelization

is not required. Where a radio link might use
several channels,

quartz crystal

oscillators are more commonly used
to drive a

phase locked loop
. Since the resonant frequency of a SAW
device is set by the mechanical properties of the crystal, it does not
drift as much as a simple LC oscillator, where c
onditions such as
capacitor performance and battery voltage will vary substantially
with temperature and age.

25.

SAW filters are also often used in radio receivers, as they can
have accurately determined and narrow pass

bands. This is helpful in
applicati
ons where a single antenna must be shared between a
transmitter and a receiver operating at closely spaced frequencies.
SAW filters are also frequently used in

television

receivers,
for
extracting

subcarriers

from the signal; until the analog switchoff, the
extraction of

digital audio

subcarriers from the

intermediate
frequency

strip of a television receiver or video recorder was one of
the main markets for SAW filters. They are also often us
ed in digital
receivers, and are well suited to

superhet

applications. This is
because the intermediate frequency signal is always at a fixed
frequency after the

local oscillator

has been mixed with the received
signal, and so a filter with a fixed frequency and high Q provides
excellent removal of unwanted or interference signals.

26.

In these applications,

SAW filters are almost always used with
a

phase locked loop

synthesized local oscillator, or a

varicap

driven
oscillator.



8


SAW Geographics


27.

In

seismology

surface acoustic waves travelling along the
Earth's surface play an important role, since they can be the most
destructive type
of

seismic wave

produced by

earthquakes
.



SAW in
microfluids


28.


In recent years, attention has been
drawn to using SAWs to
drive microfluidic actuation and a variety of processes. Owing to the
mismatch of sound velocities in the SAW substrate and fluid, SAWs
can be efficiently transferred into the fluid, to create significant
inertial force and fluid vel
ocities. This mechanism can be exploited to
drive fluid actions such as

pumping
,

mixing
,

jetting
, as well as others.


29.

This article is about the sensing technology used in human
interfaces. For the device used in distance measurements,
see

Capacitive displacement sensor
.

30.

In

electrical
engineering
,

capacitive sensing

is a technology
based on

capacitive coupling

that is used in many different types of
sensors, including those to detect and measure:
proximity,

position
or displacement
,

humidity
, fluid level, and

acceleration
. Capacitive
sensing as a

human interface device

(HID) technology, for example

to
replace the

computer mouse
, is growing increasingly popular.

Capacitive touch sensors are used in many devices such as laptop
trackpads,

digital audio players
,

computer displays
,

mobile
phones
,

mobile devices

and others. More and more design engineers
are selecting capacitive sensors for their versatility, reliability a
nd
robustness, unique human
-
device interface and cost reduction over
mechanical switches.

31.

Capacitive sensors detect anything which is conductive or has
a

dielectric

different than that of air. While capacitive sensing
applications can replace mechanical buttons with capacitive
9


alternatives, other technologies such as

multi
-
touch

and gesture
-
base
d

touchscreens

are also premised on capacitive sensing.


Sensor Design

32.

Capacitive sensors can be constructed from many different
media, such as copper,

Indium tin oxide

(ITO) and printed ink. Copper
capacitive sensors can be implemented on standard

FR4

PCBs as well
as on flexible material. ITO allows the capacitive sensor to be up to
90% transparent (for one layer solutions). The size and spacing of the
capacitive sensor are both very important to the sensor's
performance. In addition to the size of the sensor, and i
ts spacing
relative to the

ground plane
, the type of ground plane used is very
important. Since the

parasitic capacitance

of the sensor is related to
the

electric field
's (e
-
field) path to ground, it is important to choose a
ground plane that limits the concentr
ation of e
-
field lines with no
conductive object present.

33.

Designing a capacitance sensing system requires first picking
the type of sensing material (FR4, Flex, ITO, etc.). One also needs to
understand the environment the device will operate in, such a
s the
full

operating temperature

range, what radio frequencies are present
and how the user will interact with the interface.

34.

There are two types of
capacitive sensing system: mutual
capacitance,

where the object (finger, conductive stylus) alters the
mutual coupling between row and column electrodes, which are
scanned seq
uentially;

and self
-

or absolute capacitance where the
object (such as a finger) loads the sensor or increases the parasitic
capacitance to ground. In both cases, the difference of a preceding
absolute position from the present absolute position yields the

relative motion of the object or finger during that time. The
technologies are elaborated in the following section.


10


Surface capacitance

35.

In this basic technology, only one side of the insulator is coated
with a conductive layer. A small

voltage

is applied to the conductive
layer, resulting in a uniform electrostatic field. When a

condu
ctor
,
such as a human finger, touches the uncoated surface, a

capacitor

is
dynamically formed. Due to the sheet resistance of the surface, each
corner is measured to have a different
effective capacitance. 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; the larger the change in capacitance, the closer
the touch is to that corner. As it has no moving parts, it is moderately
durable. But it 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

36.

Projected capacitive touch (PCT)
technology is a capacitive
technology which allows more accurate and flexible operation,
by

etching

the conductive layer. An

X
-
Y grid

is formed either by
etching one 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
liquid crystal displays

(LCD).

37.

The greater
resolution of PCT allows operation with no direct
contact, such that the conducting layers can be coated with further
protective insulating layers, and operates

ev
en under screen
protectors, or behind weather and vandal
-
proof glass. Due to the top
layer of a PCT being glass, PCT is a more robust solution versus
resistive touch technology. Depending on the implementation, an
active or passive stylus can be used inste
ad 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
11


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 capaci
tance.


Mutual capacitance

38.

Mutual capacitive sensors have a

capacitor

at each intersection
of each row and each column. A 12
-
by
-
16 array, for example, would
have 192 independent
capacitors. A

voltage

is applied to the rows or
columns. Bringing a finger or conductive stylus near the surface of
the sensor changes the local electric field which reduces the mutual
capac
itance. The capacitance change at every individual point on the
grid can be measured to accurately determine the touch location by
measuring the voltage in the other axis. Mutual capacitance
allows

multi
-
touch

operation where multiple fingers, palms or stylus
can be accur
ately tracked at the same time.


Self
-
capacitance

39.

Self
-
capacitance sensors can have the same X
-
Y grid as mutual
capacitance sensors, but the columns and rows
operate
independently. With self
-
capacitance, the capacitive load of a finger
is measured on each column or row electrode by a current meter.
This method produces a stronger signal than mutual capacitance, but
it is unable to resolve accurately more than o
ne finger, which results
in "ghosting", or misplaced location sensing.


Circuit
Design

40.

Capacitance is typically measured indirectly, by using it to
control the frequency of an oscillator, or to vary the level of coupling
(or attenuation) of an AC
signal.

12


41.

The design of a simple capacitance meter is often based on
a

relaxation oscillator
. The capacitance to be sensed forms a portion
of the oscillator's

RC circuit

or

LC circuit
. Basically the technique
works by charging the unknown capacitance with a known current.

(The equation of state for a capacitor is i = C dv/dt. This means that
the capacitance equals the current divided by the rate of change of
voltage across the capacitor.) The capacitance can be calculated by
measuring the charging time required to reach th
e threshold voltage
(of the relaxation oscillator), or equivalently, by measuring the
oscillator's frequency. Both of these are proportional to the RC (or
LC)

time constant

of th
e oscillator circuit.

42.

The primary source of error in capacitance measurements is
stray capacitance, which if not guarded against, may fluctuate
between 10 pF to 10 nF. The stray capacitance can be held relatively
constant by shielding the (high impedan
ce) capacitance signal and
then connecting the shield to (a low impedance) ground reference.
Also, to minimize the unwanted effects of stray capacitance, it is
good practice to locate the sensing electronics as near the sensor as
possible.

43.

Another meas
urement technique is to apply a fixed
-
frequency
AC
-
voltage signal across a capacitive divider. This consists of two
capacitors in series, one of a known value and the other of an
unknown value. An output signal is then taken from across one of
the capacito
rs. The value of the unknown capacitor can be found
from the ratio of capacitances, which equals the ratio of the
output/input signal amplitudes, as measured by an AC voltmeter.
More accurate instruments may use a capacitance bridge
configuration, similar
to a

W
heatstone bridge
.


The capacitance
bridge helps to compensate for any variability that may exist in the
the applied signal.


Comparison with other touch screen
technologies

44.

Since capacitive screens respond to only materials which are
conductive (human finger used most commonly), they can be
13


cleaned with cloths with no accidental command input. Capacitive
touchscreens are more responsive than

resistive touchscreens
.
standard stylus cannot be used for capacitive sensing unless it is
tipped with some form of conductive material, such as anti
-
static
conduct
ive foam. However, capacitive styli

different from
standard
styli

can be used as well as finger input on capacitive
screens. Capacitive touchscreens are more expensive t
o manufacture
and offer a significantly lesser degree of accuracy than

resistive
touchscreens
.
[7]

Some cannot be used with gloves, and can fail to
sense correctly with even a small amount of water on the screen.

Power supplies with high electronic

noise

can reduce accuracy.


Capacitive stylus

45.

A

Capacitive stylus

is a special type of

stylus

that works on
capacitive

touchscreens

primarily designed for fingers, as
on

iPhone

and most

Android

devices. They are different from
standard styli designed for resis
tive touchscreens.

46.

According to a report by ABI Research, styli are especially
needed in China for handwriting recognition because of the nature of
its writing system.

Infrared

touch screen



14


47.

Infrared sensors mounted around the display watch for
a user's
touchscreen input on this PLATO V terminal in 1981. The
monochromatic plasma display's characteristic orange glow is
illustrated.

48.

An

infrared

t
ouchscreen uses an array of X
-
Y
infra

red

LED

and

photodetector

pairs around the edges of the screen to
detect a disru
ption in the pattern of LED beams. These LED beams
cross each other in vertical and horizontal patterns. This helps the
sensors pick up the exact location of the touch. A major benefit of
such a system is that it can detect essentially any input including
a
finger, gloved finger, stylus or pen. It is generally used in outdoor
applications and

point of sale

systems which can't rely on
a

conductor

(such as a bare finger) to activate the touchscreen.
Unlike

capacitive touchscreens
, infrared touchscreens do n
ot require
any patterning on the glass which increases durability and optical
clarity of the overall system.


Optical imaging

49.

This is a relatively modern development in touchscreen
technology, in which two or more image sensors are placed around
the
edges (mostly the corners) of the screen. Infrared back lights are
placed in the camera's field of view on the other side of the screen. A
touch shows up as a shadow and each pair of cameras can then be
pinpointed to locate the touch or even measure the si
ze of the
touching object (see

visual hull
). This technology is growing in
popularity, due to its scalability, versatility, and affordability,
especially for
larger units.


Dispersive signal technology

50.

Introduced in 2002 by

3M
, this system uses sensors to detect
the

mechanical energy

in the glass that occurs due to a touch.
Complex algorithms then interpret this information and provide the
actual location of the touch.
[15]

The technology claims

to be
15


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, an
y 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.



Acoustic pulse recognition

51.

This system, introduced by

Tyco International
's Elo division in
2006, uses

piezoelectric

transducers located at various positions
around the screen. The transducers create a standing wave on the
screen, that is interupted by a touch, and turned into an electronic
signal location.
[16]

The screen hardware then uses an algorithm to
determine the location of the touch based on the transducer signals.
The touchscreen itself is made of ordinary glass, giving it good
durability and optical clarity. It is usually able to functio
n with
scratches and dust on the screen with good accuracy. The technology
is also well suited to displays that are physically larger. As with the
Dispersive Signal Technology system, after the initial touch, a
motionless finger cannot be detected. However
, for the same
reason, the touch recognition is not disrupted by any resting objects.


Construction

52.

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.

53.

In the most popular techniques, the capacitive or resistive
approach, there are typically four layers;

a)

Top polyester coated with a transparent metallic conductive
coa
ting on the bottom

16


b)

Adhesive spacer

c)

Glass layer coated with a transparent metallic conductive
coating on the top

d)

Adhesive layer on the backside of the glass for mounting.

54.

When a user touches the surface, the system records the
change in the electrical c
urrent that flows through the display.

55.

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.

5
6.

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.

57.

In each case, the system determines the intended command
based on the controls showing on the screen at the time and the
location of the touch.


17


Development

58.

Most touchscreen technology

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.

59.

The development of multipoint touchscreens facilitated the
tracking of more th
an 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.

60.

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.


61.

The ability to accurately point on the screen itself is also
advancing with the emerging

graphics tablet/screen hybrids
.


Ergonomics and usage


Finger stress

62.

An ergonomic problem of certain types of (resistive)
touchscreens is their stress on human fingers when used for more
than a few minutes at a time, as significant pressure can be required,
depending upon the technologies involved. This can be alleviated fo
r
some users with the use of a pen or other device to add leverage and
more accurate pointing. The introduction of such items can
sometimes be problematic, depending on the desired use (e.g.,
18


public kiosks such as ATMs). Also, more accurate control is achi
eved
with a stylus, because a finger is a rather broad and ambiguous point
of contact with the screen itself, but requires the user to possess fine
motor skills to hold such a stylus.

Fingernail as stylus



63.

Pointed nail for easier typing. The concept

of using a fingernail
trimmed to form a point, to be specifically used as a

stylus
on
a

writing
tablet

for communication, appeared in the 1950 science
fiction short story

Scanners Live in Vain
.

64.

These ergonomic issues of direct touch can be bypassed by
us
ing a different technique, provided that the user's fingernails are
either short or sufficiently long.

Rather than pressing with the soft
skin of an outstretched fingertip, the finger is curled over, so that the
tip of a fingernail can be used instead.
This method does not work on
capacitive touchscreens.

65.

The fingernail's hard, curved surface contacts the touchscreen
at one very small point. Therefore, much less finger pressure is
needed, much greater precision is possible (approaching that of a
styl
us, with a little experience), much less skin oil is smeared onto
the screen, and the fingernail can be silently moved across the
screen with very little resistance,

allowing for selecting text, moving
windows, or drawing lines.

66.

The human

fingernail

consists of

keratin

which has a hardness
and smoothness similar to the tip of a

stylus

(and so will not typically
scratch a touchscreen). Alternatively, very short stylus tips are
19


available, which slip right onto the end of a finger; this increases
visibility of the contact point with th
e screen.


Fingerprints

67.

Touchscreens can suffer from the problem of fingerprints on
the display. This can be mitigated by the use of materials with

optical
coatings

designed to reduce the visible effects of fingerprint oils,
or

oleophobic

coatings as used in the

iPhone 3G S
,

which lessen the
actual amount of oil residue, or by reducing skin contact by using a
fingernail or stylus.


Combined with haptics

68.

Touchscreens are often used with

haptic

response systems. An
example of this technology would be a system that caused the device
to vibrate when a button on the touchscreen was tapped. The user
experience with touchscreens lacking tactile feedback or

haptics

can
be difficult due to latency or other factors. Research from the
University of Glasgow Scotland [Brewster, Chohan
, and Brown 2007]
demonstrates that sample users reduce input errors (20%), increase
input speed (20%), and lower their cognitive load (40%) when
touchscreens are combined with haptics or tactile feedback [vs. non
-
haptic touchscreens].


Gorilla arm

69.

The

Jargon File

dictionary of hacker slang defined

"gorilla
arm"

as the failure to understand the ergonomics of vertically
mounted touchscreens for prolonged use. The proposition is tha
t the
human arm held in an unsupported horizontal position rapidly
becomes fatigued and painful, the so
-
called "gorilla arm".


It is often
cited as a prima facie example of what not to do in ergonomics.
Vertical touchscreens still dominate in applications

such as ATMs and
data kiosks in which the usage is too brief to be an ergonomic
problem.


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70.

Discomfort might be caused by previous poor posture and
atrophied muscular systems caused by limited physical
exercise.


Fine art painters are also often
subject to neck and
shoulder pains due to their posture and the repetitiveness of their
movements while painting.



Screen protectors

71.

Some touchscreens, primarily those employed in

smartphones
,
use transparent plastic protectors to prevent any scratches that
might be caused by day
-
to
-
day use from becoming permanent.


Conclusion


72.

The touch screen interface is going to revolutionise the
electronic interactive devices in a big way.

The future multi touch
systems which has limit of imagination as drawback are going to
substantially dominate the field. The exponential growth of touch
screens are just an indication of the future of these devices.


References


www.wikipedia.com

fujitsu microelectronics

howstuffworks.com







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