Capacitive Touch Screen
Projected capacitive touch screen contains X and Y electrodes with insulation layer between them. The transparent electrodes are normally made into diamond pattern with ITO and with metal bridge.
Human body is conductive because it contains water. Projected capacitive technology makes use of conductivity of human body. When a bare finger touches the sensor with the pattern of X and Y electrodes, a capacitance coupling happens between the human finger and the electrodes which makes change of the electrostatic capacitance between the X and Y electrodes. The touchscreen controller detects the electrostatic field change and the location.
Resistive Touch Screen
A resistive touch screen is made of a glass substrate as the bottom layer and a film substrate (normally, clear poly-carbonate or PET) as the top layer, each coated with a transparent conductive layer (ITO: Indium Tin Oxide), separated by spacer dots to make a small air gap. The two conducting layers of material (ITO) face each other. When a user touches the part of the screen with finger or a stylus, the conductive ITO thin layers contacted. It changes the resistance. The RTP controller detects the change and calculate the touch position. The point of contact is detected by this change in voltage.
Which Is Better Capacitive or Resistive Touchscreen?
|Resistive Touch Screen||Capacitive Touch Screen|
|Manufacturing Process||Simple||More complicated|
|Cost||Lower||Higher: Depending on size, number of touches|
|Touch Screen Control Type||Requires pressure on the touchscreen.||Can sense proximity of finger.|
|touch with thick gloves||Always good||more expensive, need special touch controller|
|Touch Points||Single Touch Only||Single, two, gesture or Multi-Touch|
|Touch Sensitivity||Low||High (Adjustable)|
|Touch Resolution||High||Relatively low|
|Touch Material||Any type||Fingers. Can be designed to use other materials like glove, stylus, pencil etc.|
|False Touch Rejection||False touches can result when two fingers touch the screen at same time.||Good Performance|
|Immunity to EMI||Good||Need to special design for EMI|
|Image Clarity||Less transparent and smoky looking||Very high transparent especially with optical bonding and surface treatment|
|Sliders or Rotary Knobs||Possible, but not easy to use||Very good|
|Cover Glass||None||Flexible with different shapes, colors, holes etc.|
|Overlay||Can be done||No|
|Size||Small to medium||Small to very big size|
|Immunity to Objects/Contaminants on Screen||Good||Need to special design to avoid false touch|
|Resistant to Chemical Cleaners||No||Good|
|Impact Ball Drop Test||Surface film protected||Need special design for smash|
|Scratch Resistance||As high as 3H||As high as 9H|
|UV Degradation Protection||Less protection||Very good|
What Are Resistive Touch Screens Used For?
Resistive touch screens still reign in cost-sensitive applications. They also prevail in point-of-sale terminals, industrial, automotive, and medical applications.
What Are Capacitive Touch Screens Used For?
Projected Capacitive Touch Panel (PCAP) was actually invented 10 years earlier than the first resistive touchscreen. But it was no popular until Apple first used it in iPhone in 2007. After that, PCAP dominates the touch market, such as mobile phones, IT, automotive, home appliances, industrial, IoT, military, aviation, ATMs, kiosks, Android cell phones etc.