Liquid crystal display device having an improved lighting device

1. A liquid crystal display device comprising:

a liquid crystal display panel having a plurality of pixels;

a lighting device having at least one light source and projecting light generated by the at least one light source on the liquid crystal display panel; and

a circuit supplying a first current during a first period and a second current smaller than the first current during a second period to the at least one light source alternately,

wherein the circuit has a current monitoring circuit which measures the first current and the second current, and a light control circuit which adjusts a ratio of the first period to the second period based upon a signal from the current monitoring circuit.

2. A liquid crystal display device according to claim 1 , wherein a sum of the first period and the second period is kept constant without reference to the ammeter the signal from the current monitoring circuit.

3. A liquid crystal display device according to claim 1 , wherein an integral of brightness produced by the at least one light source over the second period is equal to or lower than 90% of brightness of the at least one light source during the first period.

4. A liquid crystal display device according to claim 1 , wherein the signal from the current monitoring circuit reflects a temperature variation of the at least one light source.

5. A liquid crystal display device according to claim 1 , wherein the at least one light source is a fluorescent lamp.