Question: I am going to buy a new TV. My wife likes to watch those shopping shows that always have logos on the screen and I am worried about damaging it if she watches them constantly. What TV would be my best bet?
Bob, Pittsburgh
Answer: It sounds like you have heard stories about logos being burned into screens when a single channel is displayed the majority of the time. These anecdotal stories are true, but as of late technology has moved forward to diminish the problem, known technically as Static Image Retention.
Displaying the same thing day-in and day-out is not a good idea, as no TV technology, including LCD, is immune to image retention. Even DLP projection TVs using moving mirrors have been reported to experience "mirror fatigue" which causes image retention.
Though LCD is generally thought to be immune, there are cases where it does occur when pixels get stuck after displaying the same image for too long. This was the subject of a column I wrote some time ago, and the manufacturer provided the reader with a new set. You can sometimes clear the stuck pixels by tuning the TV to an empty channel so you see "snow," turn the brightness up all the way, and leave the TV on overnight.
CRT (tube) and plasma sets are most susceptible to image retention because they use phosphors to create the image. When the same image is displayed day after day, hour after hour, it can cause phosphors to burn unevenly in the logo area compared to the rest of the screen, which changes constantly.
The latest plasma sets have taken measures to eliminate image retention. Panasonic has approached the problem directly by developing improved phosphors that eliminate uneven burning. These new phosphors are used in conjunction with a method called "orbiting" that moves the image from pixel to pixel in a manner the viewer cannot detect. Writing for Home Theater Magazine, Geoff Morrison said he tried as hard as he could to burn an image into a Panasonic 42 inch plasma TV, but couldn't. There is also a scrolling bar you can activate in the setup menus that effectively wipes the screen image clean.
Samsung, the other large plasma manufacturer, uses automatic pixel shifting to combat image retention and has both scrolling bar and white screen options in the setup menus. I have a Samsung plasma in my bedroom and once fell asleep while watching it. My DVR locked up and I woke to a frozen picture with sports scores across the bottom, which had been there for two hours. I turned on the white screen and you could definitely see an image ghosting across the white. Within 30 seconds the white screen had completely eliminated the retained image, and my set was good as new.
If you want to be extra-careful, buy an LCD television from a major manufacturer. If you want a plasma, I would get one of the Panasonic models due to the advanced and proven anti-image-retention technology.
No matter what you buy, try to remember to change the channel once in a while and use the scrolling bar on the plasma set before you turn it off for the day. No point pushing your luck.
First Published: October 4, 2009, 4:00 a.m.
