Gold cake desk

I have a toshiba 63" hd widescreen,now its starting to look dark.? - toshiba tvs nice small screen lcd tv

I have the TV there are about 2 years and it looked so beautiful and bright, now it is gradually bleak. I thought of buying a new bulb, but do not know much about TV. Assistance needs to be clarified, or buy elsewhere? in the thinking work, but I want safe, cuz do their part of $ 200.