There are three LCD
display types: segment (or alphanumeric), dot matrix (or character) and
graphic LCD.Segment LCD (or Alphanumeric LCD)
Segment LCD can display Arabic numbers
represented by 7 segments or Arabic numbers and Roman letters represented by
14 segments. Symbols, such as plus/minus signs, measurement units and any
custom icons, can also be displayed. Each symbol is treated as one segment.
Segment LCD is widely used on the
displays of scientific instruments. It is easy to control and most
cost-effective to develop.
Segment LCD is limited to displaying
numbers, Roman letters and fixed symbols. If you need to display anything
else, you have to use either the dot matrix display or graphic display.
Dot Matrix LCD (or Character LCD)
Dot matrix LCD is used to display a
number of lines of characters. The most commonly used dot matrix LCD
displays 1 to 4 lines of 16 to 40 characters. Each character is represented
by 5x7 dots plus cursor (actually 5x8 dots including the cursor). Each
character block is addressed separately and can form numbers, Roman letters,
character in other languages and a limited number of symbols.
Dot matrix LCD is used when you need to
display more characters than those in English alphabet. It is relatively
simple to control and also inexpensive than graphic models.
Graphic LCD
Graphic LCD provides users with a greater degree of
flexibility. They are composed of pixels arranged in rows and columns. Each
pixel can be addressed individually for text, graphics or any combination of
the two.
Graphic LCD is used in applications
when the use need to have total control of the whole viewing area. However,
flexibility also comes with the difficulty in designing the control
circuitry. Fortunately there are special controller chips available for this
purpose. |
