Hello there! My name is Ken and I am a Chinese senior high top student in Guangdong Country Garden School. Welcome to Ken's Study Journey website with Computer Science knowledge explanations!
Recently, iPhone 13 and Apple Watch 7 were released. Both of them are using OLED screen display, which is a new technology that can make the screens thinner.
OLED screen was implemented as early as iPhone X, which takes advantage of Apple products. This kind of technology is used on not only phones and watches, but also some TV screens and other screens.
It can be bent to any shape and it is much thinner than the previous LCD (CCFL and LED backlighting) technology, giving people a wide angle of view when watching some virtual reality things.
Do you know why OLED can bring many benefits to Apple devices, and some technical reasons behind it? Let's go!
What is OLED Screen?
OLED screen is shorted by Organic Light Emitting Diode. It is a new technology that uses organic materials such as carbon (C) compounds, and plastics layers.
LCD and OLED screens are covered in IGCSE Computer Science (0478) syllabus, so I have fully learned this kinds of knowledge.
OLED does not require backlighting and it can be lit by itself with 2 electrodes around (anode and cathode), so it uses less power and it can be much thinner.
iPhone X uses OLED screen.
Types of Screen
There are two types of screens on our phones and computers: LCD and OLED.
LCD is shorted by Liquid Crystal Display, which has 2 separate types: older CCFL and newer LED.
There are thousands of pixels (e.g. 1920x1080) on the screen made by RGB (Red, Green and Blue). It requires backlighting so there is a white light behind, being filtered by the RGB colours.
The first type is the older CCFL, which is shorted by Cold Cathode Fluorescent Lamp.
It uses fluorescent tubes behind the screens, which may turn yellow as it has a limited lifespan (approximately 5 years). Also, it may be very thick, like old computer screens.
To overcome these two problems, LED was developed and it takes advantage of screen display.
LED is shorted by Light Emitting Diode, which uses small white LED lights at the back.
It has the following benefits than CCFL:
- It reaches its maximum brightness almost immediately because the lights behind do not need to warm up for a long time.
- It is much thinner because the LED lights behind are much smaller.
- It has a long lifespan, which does not turn yellow after several years.
- Its light is more bright and white, so the images on the display can be more vivid.
- It consumes less power than CCFL so it produces less heat with less energy.
Another type of screen is OLED, which has a lot of benefits than LCD and LED.
- It is a self-contained system which does not require backlighting.
- It uses less power than LCD screens.
- It is thinner and lighter.
- It uses plastics, so it can be made into thin and large sheets.
- It has larger angles (about 170 degrees).
Extra Knowledge: Touchscreens
This are the knowledge about OLED screens on the new iPhone and Apple Watch. By the way, I also want to talk about touchscreens, which is relevant to screens.
There are 3 types of touchscreens, capacitive, infra-red and resistive.
Capacitive is the most common type of touchscreen on phones and iPad.
It uses many layers like a capacitor that stores electricity charges. When we touch the top layer of the screen, the charge at the corresponding place is transferred to our hands. Then, the coordinate is determined by the on-board microprocessor.
Because it uses electricity, we cannot touch the screen with gloves because the glove is an insulator while our fingers are conductors.
Another type of touchscreen is infra-red.
It uses infra-red emitters and receivers at the edges of the screen, forming a grid of infra-red signals around it.
When we touch the top layer of the screen, some infra-red signals are stopped by our fingers so the receivers at the corresponding positions cannot receive the signal and hence the coordinates are determined.
It allows touching using gloves because the infra-red signal can be interrupted by any opaque solids. By the way, we can touch the infra-red screens using insulators such as pens.
Because it is an expensive technology, while capacitive is a medium-cost technology, it is not commonly used for screens on major devices.
The last type of touchscreen is resistive.
It uses 2 layers that conduct electricity. The top layer uses plastics and the bottom layer uses glass.
Normally, these two layers are separate. When we touch the top layer, 2 layers form a complete circuit so the coordinate is determined.
Albeit it is a relatively cheaper technology, it has many disadvantages compared with capacitive and infra-red:
- It does not permit multi-touch (i.e. touching the screens using many fingers at the same time) because the middle part between 2 fingers is also pressed when we touch it using 2 fingers, so the coordinates can't be determined accurately.
- The screen visibility can be poor in strong sunlight.
- It can be broken easily if it experiences scratches.
Determining the Type of Touchscreens
We can use several ways to determine the type of touchscreens.
Firstly, if we need some pressure to touch the screen, it is probably resistive because we need some force to press the top layer to the bottom.
Then, we can use some insulators, such as pens and gloves, to touch the screen. If it works, it is probably infra-red. Otherwise, it may be capacitive.
OLED takes advantage of screens on phones and computers because it is much thinner and brighter than LED and CCFL.
Alright! This is the end of the computer science knowledge explanation of OLED screens on iPhone 13 and Apple Watch 7. Thanks for reading and I hope you can understand the computer science knowledge behind on new Apple products.
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