What is a Touchscreen made of?
What is a Touchscreen made of?
A grid of transparent electrodes measuring the tiny capacitance your finger adds — which is why gloves fail.
Projected capacitive screens do not sense pressure or heat; they sense the change in an electric field caused by something conductive and earthed nearby. That is why a gloved finger does nothing — the glove is an insulator and holds the conductive hand too far away — and why touchscreen gloves have conductive thread woven into the fingertips. It is also why water on the screen causes phantom touches: droplets are conductive enough to look like fingers. A passive stylus works only if it presents a large enough conductive contact patch coupled to your hand, which is why they have fat rubbery tips, while an active stylus contains its own electronics and can be a fine point.
Component by component
| Part | Material | Why that material |
|---|---|---|
| electrode grid | indium tin oxide, or fine metal mesh, in rows and columns | It has to be conductive and invisible at the same time; ITO is the long-standing compromise, metal mesh the cheaper newer one. |
| controller | a dedicated chip driving each row and reading each column | It measures capacitance at every intersection tens of times a second, which is what makes multi-touch possible. |
| cover glass | strengthened glass, acting as the dielectric | The finger never touches the electrodes; it changes the electric field through the glass, so the sensor can be fully sealed. |
| resistive alternative | two conductive films separated by tiny spacer dots | It works with a stylus, a fingernail or a glove because it senses pressure, which is why it survives in industrial and medical kit. |
Other electronics objects
- Alkaline battery Zinc powder and manganese dioxide either side of a potassium hydroxide paste, in a steel can.
- Smartphone screen Chemically strengthened aluminosilicate glass over a touch layer and an OLED or LCD panel, with an oil-shedding coating on top.
- Solar panel Doped silicon wafers with silver contacts, sealed between low-iron glass and a plastic backsheet in an aluminium frame.
- LED bulb Blue LED chips under a yellow phosphor, plus a driver circuit and a heat sink — and it is the driver that dies.
- Computer keyboard ABS or PBT keycaps over either a silicone rubber dome on printed film, or individual mechanical switches.
- Headphones A neodymium magnet, a coil of copper wire and a thin plastic diaphragm — a loudspeaker shrunk to fit an ear.
- Loudspeaker A paper or plastic cone hung on a rubber surround, driven by a coil in a magnet gap.
- Computer mouse An ABS shell around a tiny camera taking thousands of pictures a second, plus two clicky microswitches and PTFE feet.
Common questions
- What is a Touchscreen made of?
- A grid of transparent electrodes measuring the tiny capacitance your finger adds — which is why gloves fail.
- What is the electrode grid of a Touchscreen made of?
- Indium tin oxide, or fine metal mesh, in rows and columns. It has to be conductive and invisible at the same time; ITO is the long-standing compromise, metal mesh the cheaper newer one.
- What is the controller of a Touchscreen made of?
- A dedicated chip driving each row and reading each column. It measures capacitance at every intersection tens of times a second, which is what makes multi-touch possible.
Related pages
- Alkaline battery Zinc powder and manganese dioxide either side of a potassium hydroxide paste, in a steel can.
- Smartphone screen Chemically strengthened aluminosilicate glass over a touch layer and an OLED or LCD panel, with an oil-shedding coating on top.
- Solar panel Doped silicon wafers with silver contacts, sealed between low-iron glass and a plastic backsheet in an aluminium frame.
- LED bulb Blue LED chips under a yellow phosphor, plus a driver circuit and a heat sink — and it is the driver that dies.
- Computer keyboard ABS or PBT keycaps over either a silicone rubber dome on printed film, or individual mechanical switches.
- Headphones A neodymium magnet, a coil of copper wire and a thin plastic diaphragm — a loudspeaker shrunk to fit an ear.
- Loudspeaker A paper or plastic cone hung on a rubber surround, driven by a coil in a magnet gap.
- Computer mouse An ABS shell around a tiny camera taking thousands of pictures a second, plus two clicky microswitches and PTFE feet.
- Pencil Stationery and paper
- Tennis ball Sport and games
- Banknote Around the house
- Golf ball Sport and games
- Paper Stationery and paper
- Glass Building materials
Sources
- Typical range compiled from manufacturer specifications — At One Place