Only light is the difference between all type of tv you have mentioned in your quarry.
In CRTs manufacturers used the "cathode ray Tube", in LCDs manufacturers were using the CCFLs for lighting purpose and in TFT tv maker is using the "thin film transistor" to improve the image quality....!!
For more detail about the TFT just chec this link:
http://en.wikipedia.org/wiki/TFT_LCD