LCD panel brightness is normally expressed in terms of Nits or Candelas/meter2 (cd/m2), they are equivalent, and refers to the manufacturers measurement under the following conditions:
- After the backlight has had time to warm up to reach full potential,
- From directly in front of the middle of the panel,
- With transmissivity at maximum, so if the panel is normally white then probably with no input signal or if the panel is normally black then with a full white signal.
There are no standards for suitable brightness levels for various applications which is reasonable considering other factors will affect the outcome but as a general guideline it would seem that the following ranges apply:
- Notebook type computers: Around 200~250 Nits
- Desktop monitors: Typically up to 450 Nits
- TV’s and video displays: 400~600 Nits
- Public displays: Generally around 600~700 Nits
- Outdoor displays: 700~1,500 Nits.
Other factors: Contrast – as I was being told this morning a 700 Nit panel with excellent contrast proved to be considerably better in an outdoor application than a 1,500 Nit panel with lower contrast.
The bottom line is that it is very difficult to make a decision based on the specifications and the display needs to be evaluated in its environment.
Some applications require low light visibility which is another topic.