CLICK HERE FOR INDEX PAGE
 
LIQUID CRYSTALS - A MODERN MATERIAL
V.Ryan © 2021
 
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET
 
CLICK HERE FOR POWERPOINT VERSION OF WORKSHEET
 
Once it was believed, that there were only three states of matter; solid, liquid, and gas. Today there are considered to be four states, with ‘liquid crystals’ being the fourth, falling between the solid and liquid phases.
 
Liquid crystal molecules are elongated, sometimes described as banana or rod shaped. When exposed to an electric current or magnetic field, the molecules align in a direction along a common axis, they can also form layers.
 
 
Liquid crystals are substances that blend the properties of a crystalline state, with the flowing characteristics of a liquid. They are capable of having their molecules rearranged when electricity is applied. This property means that liquid crystals have special, practical applications in science and engineering including; thermometers, wristwatches, calculators, computer screens and modern televisions. The design and manufacture of Liquid Crystal Displays (LCDs) worldwide, is worth multi-billions of pounds.
 
 
 
There are two types of liquid crystal display, monotone and full colour. Monotone have a single colour, for example the seven segment display. The letters / numbers are dark grey or black. The background is light grey and backlit, so that the letters / numbers standout. A full colour LCD display, displays a full range of colour (see explanation of LCD TV).
 
 
SIMPLE MONOCHROME LIQUID CRYSTAL DISPLAY
 
This is a typical basic, seven segment LCD. It displays a single number at a time. A segment is made up of a matrix of pixels, which are switched ‘on’ or ‘off’ at the same time. This means that each segment is either ‘on’ (positive) or ‘off’ (negative). The segments are controlled in order to display a particular number. These types of display are common in alarm clocks and digital counters.
 
 
 
 
A monochrome LCD requires low levels of power. Therefore, they are ideal for products such as solar powered calculators. Sometimes full colour displays are not required. A calculator needs a simple, easy to understand display.
The display produces a crisp, sharp image, due to the contrast between the ‘backlit’ background and the dark numbers.
 
 
MORE EXAMPLES OF MONOCHROME LCD DISPLAYS
 
 
 
 
HOW THE LIQUID CRYSTAL COLOUR DISPLAY OF A TV WORKS
 
A typical LCD TV screen has 2,000, 000 individual pixels. The pixels form the picture that you see on the TV screen. Each pixel can be switch ‘on’ or ‘off’ using polarised liquid crystals, creating a red, blue, or green light source. The way the pixels are controlled, produces the sharp colour image on the TV screen.
 
 
GENERAL PROPERTIES OF LCDs
 
Liquid crystal displays can be very bright. The power supply determines brightness. They produce very low electromagnet fields and therefore do not interfere with other electronic equipment or components. Their power consumption is very low, keeping costs down. They can be powered by a low voltage. They are thin and lightweight, capable of very sharp images.
 
CLICK HERE FOR ELECTRONICS INDEX PAGE
 
Google
 
Web www.technologystudent.com