Samsung 32" widescreen tv with green diagonal 'scan' lines across it?

an anyone help me. We have a 32" widescreen tv which has recently started showing diagonal green lines across the screen. These are there permanetly but you cannot always see them, some channels they are very faint to hardly there, other channels they are very clear. We don't know if we can get rid of these permanently or whether the tv is broken in this respect. We have a perfect picture otherwise.

If anyone could give me some advice on what might be wrong or how this can be repaired would be very greatful. It is a Samsung 32" widescreen tv

A photo can be seen at the following link:

http://img.photobucket.com/albums/v409/dimplesds/photo158.jpg

Thanks!