Samsung thinks it will hurt your eyes if you just take any LCD monitor as secondary display for your laptop. The solution from Samsung is called Lapfit. The Samsung Lapfit LCD displays mimic the look of a Laptop screen.
Samsung currently offers two Lapfit monitors with the 19 inch LD190G and the 22 inch LD220G.
Of course besides the look there is some merit in having a secondary monitor that has the same height when placed next to a notebook screen for ergonomics.
The Samsung Lapfit displays can be tilted from 10-30 degrees and can be connected via USB.
Via the Samsung Korea site.