Materials in a Mobile Phone

Almost everyone has a mobile phone. They have become even more important recently for staying in contact with friends, playing games and even keeping up to date with school work especially during lockdown.

But what is your phone made of, and how do these components work?

Your body is made up of about 24 different elements that work together to make you but your mobile phone is even more complicated as it contains more than 38 different elements many of which are much harder to find on Earth than the ones that are inside you.

This video shows how some of these rare elements are used to build the components of our mobile phones, and explains how these components work to build touchscreens, vibrating motors and cameras.

You’ll learn:

• How the colours that light up your phone screen display work with the help of polarisation, electricity and liquid crystals.
• The way the screen senses touch using light transparent conductive coatings.
• How a neodymium magnet makes your phone vibrate.
• What the lenses in your camera are made of and how this focusses light onto a light sensitive detector.

Prefer to skip through?

• 0:00-03:50 – Introduction
• 03:50-06:50 – What is a phone made of? > 38 common and uncommon elements that are used to make a mobile phone on the periodic table.
• 06:50-11:50 – The screen. Optical microscopy of the pixels in white light and individual colours.
• 11:50-14:30 – Shuttering and how the pixels work. Polarisation of light.
• 14:30-21:50 – Liquid crystals. Optical microscopy of crystals in between crossed polars, a liquid crystal molecule.
• 21:50-27:40 – Putting it all together in your phone screen. Sandwich construction from bottom up = light source, polariser, liquid crystal, crossed polariser. Effect of electricity on liquid crystal in pixels and how that affects light.
• 27:40-28:30 – Polarising sunglasses. Stop you seeing a screen well because of polarising lenses.
• 28:30-35:25 – Touch sensitive screen. Capacitive touch sensitivity / detectors in optically transparent yet conductive indium tin oxide.
• 35:25-40:20 – Vibration alert motor. Neodymium electromagnet and some coils of wire. Applying current makes a magnetic field that spins the part of the device that contains the coils, making the vibration.
• 40:20-41:50 – Phone camera. Lens system contains a coil of copper wire and neodymium magnets to focus light on the CMOS (complementary metal-oxide semiconductor) light sensitive detector.
• 41:05-48:08 – Wrapping up, thank yous and Q & A.

Glossary

Polarisation – light waves are passed through parallel slots in a grating to only let light waves with one direction pass through.

Liquid crystal – molecules that have sections that are rigid and can form ordered crystals and sections that are flexible so they can behave like liquids.

Capacitance – touching a conductive material changes how much electric charge that material can hold. Our mobile phone detects these changes to detect when and where we touch the screen.

Neodymium magnet – a strong electromagnet that is really quick to switch on and off, but relies on a rare element (neodymium).

Further Info

For Teachers: For more information about using this resource in the classroom click here (downloadable pdf).

For Families: For more information about how you can use this resource in the home click here (downloadable pdf).

For a nice infographic about materials in a smartphone follow this link: The Chemical Elements of a Smartphone – Compound Interest (compoundchem.com)