Some Lenovo customers are concerned about ghosting on LCD screens in the ThinkPad X220 laptop, in which images temporarily remain fixed on screens, but the company tried to allay fears by saying that images dissipate in a short time and do not damage panels.
The ghosting phenomena -- commonly called image persistence -- are common to LCDs and do not cause images to burn into displays, said Ray Gorman, a Lenovo spokesman, in an e-mail. But some customers have raised concerns, saying the image persistence was prominent, and the issue was not as seemingly normal as projected by Lenovo.
Lenovo offers some ThinkPad X220 laptop models with screens using IPS (in-plane switching) technology, which provides richer color and better viewing angles. Lenovo has issued a X220 support document saying that image persistence can be prevented by using screen savers and power management tools to turn off the display when the screen is inactive.
Users create image persistence by disabling screen savers and leaving a fixed image on a screen for extended periods of time, Gorman said. The image can be viewed only with a very light grey or off-white background, and the image dissipates in a short amount of time. The persistent image is caused by the discharge of residual electromagnetic charges internal to the LCD panel, and the image goes away after the charge has dissipated.
Though common, ghosting is not usually easy to notice on laptop screens, said Josh Kaplan, president of computer repair firm Rescuecom. Ghosting can, however, be an annoyance if noticeable, as images could linger on screens for longer, Kaplan said.
Image persistence has been reported on other panels in the past. Apple has provided a support document on how to avoid image persistence on the company's LCD screens.
One Lenovo customer, Albert Chosky, purchased two ThinkPad X220T laptops and found the ghosting issues "prominent." He said Lenovo was trying to be ambiguous about the genuine issue with the panels.
"I have used several IPS screens, but never found a faulty one like Lenovo is attempting to sell," said Chosky, who is an artist and photographer with a studio in Ohio. He contacted Lenovo for help on the ghosting issue, but the laptop panels were not replaced.
"It seems as if they keep ignoring any important questions, and just hope the users of their laptops will stop complaining so that they won't have to recall and fix these faulty screens," Chosky said.
However, not all customers are dissatisfied. One customer who declined to be named owned three X220 laptops, and did not notice ghosting. The X220 is priced at a premium, which could make customers more sensitive to problems, the customer said.
Lenovo did not respond to requests for comment on how the company would respond to customer concerns.
No display is perfect and it's hard to determine whether the Lenovo issue is a mountain or a mole hill, said Raymond Soneira, president of DisplayMate Technologies.
The medium-term image retention on LCDs results from a temporary charge build-up and the temporary migration of impurities within the liquid crystal, or due to temperature shifts within the panel that result from the variation of intensities within the screen image.
"The user will see ghost images until the charges, impurities and temperature imbalances dissipate over time -- generally within 15 minutes in our experience. There should be no long-term effects from this. A full-screen, uniform, dark gray image is the best way to detect the ghost images," said Soneira, whose company offers software to test multiple types of displays and projectors.
The image-retention effect is generally more noticeable in plasma panels, but it is very unusual to hear complaints from users about it on LCD panels, Soneira said.
"All LCD and plasma displays will have this effect to some degree -- but if the effect is unusually large it could be an indication of a manufacturing problem," Soneira said. Users can do side-by-side comparison tests between the Lenovo model in question and other comparable models to see what the visual differences are, he said.