Poor screen brightness

Hi,

I have an inspiron 1520 running Vista 32 bit. Battery still healthy.

Despite setting the brightness to maximum in power options when on battery, I can hardly read the screen unless the room is in darkness. I'm not sure if this has always been the case as I haven't needed this facility until recently.

Other laptops I have seen have the facility to raise the brightness (at the expense of battery life) to the same level as when plugged in.

Any suggestions greatly appreciated.