page_title: Touchscreen
section_title: Construction
hierarchical_section_title: Touchscreen / Construction
caption_attribution_description: English: This diagram shows how eight inputs to a lattice touchscreen or keypad creates 28 unique intersections, as opposed to 16 intersections created using a standard x/y multiplexed touchscreen .
context_page_description: A touchscreen, or touch screen, is both an input and output device and normally layered on the top of an electronic visual display of an information processing system. The display is often an LCD or OLED display while the system is usually a laptop computer, tablet, or smartphone. A user can give input or control the information processing system through simple or multi-touch gestures by touching the screen with a special stylus or one or more fingers. Some touchscreens use ordinary or specially coated gloves to work while others may only work using a special stylus or pen. The user can use the touchscreen to react to what is displayed and, if the software allows, to control how it is displayed; for example, zooming to increase the text size.
  The touchscreen enables the user to interact directly with what is displayed, rather than using a mouse, touchpad, or other such devices.
  Touchscreens are common in devices such as game consoles, personal computers, electronic voting machines, and point-of-sale systems. They can also be attached to computers or, as terminals, to networks.
context_section_description: 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.
  In the resistive approach, which used to be the most popular technique, there are typically four layers:
  Top polyester-coated layer with a transparent metallic-conductive coating on the bottom.
  Adhesive spacer
  Glass layer coated with a transparent metallic-conductive coating on the top
  Adhesive layer on the backside of the glass for mounting.
  When a user touches the surface, the system records the change in the electric current that flows through the display.
  Dispersive-signal technology 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.
  There are two infrared-based approaches. In one, an array of sensors detects a finger touching or almost touching the display, thereby interrupting infrared light beams projected over the screen. In the other, bottom-mounted infrared cameras record heat from screen touches.
  The x/y layout, commonly used in touchscreens, has also been improved by using a diagonal lattice layout, where there are no dedicated x or y elements, but each element may be transmitting or sensing at different times during a scan of the touchscreen. This means that there are nearly twice as many cross-over points for a fixed number of terminal connections and no 'bussed' connections around the edges of the touchscreen .
  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.
caption: This diagram shows how eight inputs to a lattice touchscreen or keypad  creates 28 unique intersections, as opposed to 16 intersections created using a standard x/y multiplexed touchscreen .
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