Horizontal Lines on Plasma TV

We have a sony bravia at home and for the past week we noticed some horizontal lines across the screen. We pay no mind as it disappears after few minutes of watching TV. It happens when you first turn on the tv. Now for the past days, more thin fine lines are coming out and sometimes you cannot see the picture anymore. It is like a blank blue screen with plaid colored design on it. You can still hear the sound though. We cannot watch anything so we just turned it off. Few minutes later, my husband turned it back on and the lines were gone. Fine again but not permanently. We still get the lines every now and then. My husband was saying maybe it’s time to change the bulb…..like what bulb???? Is this a plasma defect or a symptom of trash the tv/spend a lot of money for repair thing?!!
This TV is more than a year old. If I remember we bought it from Costco sometime August or September last year.

Anybody had this problem with their tv?