Not a well known make, but we have found that the Evotel LCD40USBFHD uses the same screens that you will find in a lot of Samsung TVs. These sometimes get a fault where the picture is too bright or the colour runs or shows the wrong colours in faces etc. The picture may become solarised or negative, and all these faults may be present on switch on or occur after the tv has warmed up after a few minutes.

This is usually due to components overheating, and not necessarily a faulty screen.

Good news is that we now have the components in to repair this fault, and return your picture to its formal glory.

Known affected models:
Evotel LCD40USB
Evotel LCD40USBFHD