22-07-2014, 10:23 AM
TOUCHSCREEN TECHNOLOGY
[attachment=66093]
INTRODUCTION
A Touchscreen Technology is an input device that allows the user to PC software directly by touching the display screen.
It allows the user to directly interact with the PC softwares without using the primary input devices such as the mouse or keyboard.
It enables the peoples to use the computer or its functions without any training.
HOW DOES A TOUCHSCREEN WORKS ?
It basically comprises of the 5 elements:
1. Bezel or Front Panel:- The bezel forms the outermost skin of the touch screen. It is the protective layer of the screen so as to protect it from the scratches and marks. Also used for sensing the touch made by the user.
2. LCD :- The screen is basically made by the LED and Cathode ray tube. It is based on the principle that a small electrical change takes place in the crystal array of LCD where it gets pressure from the touch.
PROJECTED CAPACITIVE
The projected capacitive are same as of resisitive type contains two ITO layers, but these glass layers are etched and the perpendicular strips are made at the end of the layer.
These strips forms the grid pattern like pixels projects the electric field.
So when the user touches the screen it changes the measured capacitance values of the electrode which is generally of 15pF.
SURFACE CAPACITIVE
In the surface capacitance the only one ITO
glass layer is used.
The computer measure the capacitance from
all the four corners.
Then the four separate measurements, the X
and Y coordinates of the touch point are
calculated, the capacitance is of 15 pF.
. INFRARED TOUCHSCREEN
In this technique the LED and photodetectors
are used.
The LED beams cross over the glass panel horizontally and vertically, also the photodetector is used to spread the electrical signal on the glass panel.
The photodetector gets enhance by the visible rays of the LED and produces the electrical signal.
. OPTICAL IMAGING TOUCHSCREEN
In the optical imaging touch screen the
image sensors are placed at the corners of
the screen and the infrared backlights are
focused from the sides of the screen on the
glass panel.
When we touch the screen, the touch shows
up the shadow and the image sensors locate
the touch and even the size of touch object
and send information to controller.
ADVANTAGES
Touchscreen gadgets usually have simple
user interface and are more intutive.
Replaces keyboards and mouse.
Operated using a stylus or a glove finger.
High clarity, completely sealable.
High resolution and accuracy.
Faster response.
DISADVANTAGES
Big screen leads to low battery.
This devices require massive computing
power.
When an application crashes without
crashing the operating system you can’t get
the main menu as the whole screen
becomes unresponsive.
Screen gets very dirty.
They have low precision.
Screen can damage by the sharp objects.
[attachment=66093]
INTRODUCTION
A Touchscreen Technology is an input device that allows the user to PC software directly by touching the display screen.
It allows the user to directly interact with the PC softwares without using the primary input devices such as the mouse or keyboard.
It enables the peoples to use the computer or its functions without any training.
HOW DOES A TOUCHSCREEN WORKS ?
It basically comprises of the 5 elements:
1. Bezel or Front Panel:- The bezel forms the outermost skin of the touch screen. It is the protective layer of the screen so as to protect it from the scratches and marks. Also used for sensing the touch made by the user.
2. LCD :- The screen is basically made by the LED and Cathode ray tube. It is based on the principle that a small electrical change takes place in the crystal array of LCD where it gets pressure from the touch.
PROJECTED CAPACITIVE
The projected capacitive are same as of resisitive type contains two ITO layers, but these glass layers are etched and the perpendicular strips are made at the end of the layer.
These strips forms the grid pattern like pixels projects the electric field.
So when the user touches the screen it changes the measured capacitance values of the electrode which is generally of 15pF.
SURFACE CAPACITIVE
In the surface capacitance the only one ITO
glass layer is used.
The computer measure the capacitance from
all the four corners.
Then the four separate measurements, the X
and Y coordinates of the touch point are
calculated, the capacitance is of 15 pF.
. INFRARED TOUCHSCREEN
In this technique the LED and photodetectors
are used.
The LED beams cross over the glass panel horizontally and vertically, also the photodetector is used to spread the electrical signal on the glass panel.
The photodetector gets enhance by the visible rays of the LED and produces the electrical signal.
. OPTICAL IMAGING TOUCHSCREEN
In the optical imaging touch screen the
image sensors are placed at the corners of
the screen and the infrared backlights are
focused from the sides of the screen on the
glass panel.
When we touch the screen, the touch shows
up the shadow and the image sensors locate
the touch and even the size of touch object
and send information to controller.
ADVANTAGES
Touchscreen gadgets usually have simple
user interface and are more intutive.
Replaces keyboards and mouse.
Operated using a stylus or a glove finger.
High clarity, completely sealable.
High resolution and accuracy.
Faster response.
DISADVANTAGES
Big screen leads to low battery.
This devices require massive computing
power.
When an application crashes without
crashing the operating system you can’t get
the main menu as the whole screen
becomes unresponsive.
Screen gets very dirty.
They have low precision.
Screen can damage by the sharp objects.