- 1 Backlit flat-panel displays
- 2 Self-lit
- 3 On image persistence / burn-in
- 4 VFD
- 5 Lighting
- 6 Mechanical
- 7 LED segments
- 8 DIY
Backlit flat-panel displays
There are roughly two parts of such monitors you can care about: How the backlight works, and how the pixels work.
CCFL or LED backlight
On image persistence / burn-in
7-segment and others
|This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, or tell me)|
These are really just separate lights that happen to be arranged in a useful shape.
Very typically LEDs (with a common cathode or anode), though similar ideas are sometimes implemented in other display types - notably the electromechanical one, also sometimes VFD.
Even the simplest, 7-segment LED involves a bunch of connectors so are
- often driven multiplexed, so only one of them is on at a time.
- often done via a controller that handles that multiplexing for you
Seven segments are the minimal and classical case, good enough to display numbers and so e.g. times, but not really for characters.
More-than-7-segment displays are preferred for that.
LCD character dislays
The idea is the same, the interface different - character displays are basically those with predefined (and occasionally rewritable) fonts.
The more barebones interface is often a 16 pin line with a pinout like
- usually there's a (trim)pot from Vcc, or a resistor if it's fixed
- RS: Register Select (character or instruction)
- in instruction mode, it receives commands like 'clear display', 'move cursor',
- in character mode,
- RW: Read/Write
- tied to ground is write, which is usually the only thing you do
- ENable / clk (for writing)
- 8 data lines, but you can do most things over 4 of them
- backlight Vcc
- Backlight gnd
So minimal setup is:
- tie RW to ground
- tie RS, EN, D7, D6, D5, and D4 to digital outs
I2C and other
These are sometimes called OLED, for reasons I don't yet understand.