groundFungus:
There are the display() and noDisplay() functions that turn the display of characters on and off.
And in other lcd libraries like the hd44780 library, there is also off() and on() which not only turns the LCD pixels off/on, as is done with noDisplay() and display() but if you have h/w backlight control using an Arduino pin, and configure the library to use it, the off()/on() will also turn off/on the backlight as well.
--- bill