Touch Screens

Question 1

3 types of touchscreens

Answer 1

Capacitive, Resistive and Infrared

Question 2

What a touch screen does

Answer 2

Allows the user to carry out same functions as a pointer device

Question 3

Describe how a resistive screen works

Answer 3

• This screen is made up of two layers
  *The user pushes these layers together
  *The layer creates a circuit when pushed
  *Causing electricity to flow

Question 4

Benefits of a Resistive touch screen

Answer 4

• Cheap to buy
• Can be used whilst wearing gloves
• Resistant to water

Question 5

Disadvantages to a Resistive touch screen

Answer 5

• Longevity issues
• Lower resolution
• Prone to scratches

Question 6

Stored program concept

Answer 6

A concept that allows computers to execute different programs by storing instructions in memory, enabling flexibility and programmability

Question 7

Describe how a capacitive screen works

Answer 7

• This screen is composed of three layers
• Skin changes the electrostatic field of the conductive layer
• The microcontroller calculates the coordinates of the finger.

Question 8

Two types of Capacitive touch screens

Answer 8

• Surface
• Projective

Question 9

Differences between Surface and Projective Capacitive touch screens

Answer 9

Projective can work with cotton gloves, while surface cannot.

Projective allows a multi-touch facility, while surface does not.

Question 10

Advantages of Capacitive touch screens

Answer 10

• Better image clarity than resistive
• Very durable
• Projective screens allows multi touch

Question 11

Disadvantages of Capacitive touch screens

Answer 11

• Surface capacitive screens only work with fingers or stylus
• Sensitive to electromagnetic radiation
• Higher cost than resistive

Question 12

Describe how infrared touch screens work

Answer 12

• The screen has an array of sensors and infrared transmitters.
• Sensors detect infrared radiation
• Sensor readings are sent to microcontroller that calculates where screen was touched

Question 13

Advantages of infrared touchscreens

Answer 13

• Allows multi-touch facilities
• Has good screen durability
• Scratched or cracked screen does not affect operability

Question 14

Disadvantages of infrared touchscreens

Answer 14

• Sensitive to water
• Sometimes sensitive to light interference
• Possible for accidental activation is infrared sensors are disturbed