Either the resolution, or the vertical fresh rate, or both of these settings of your graphics card has exceeded the range of the LCD.

• First, determine the resolution of your LCD. If your graphics card is set to a higher resolution than that of the LCD, you must reset it to the LCD's resolution (or a resolution below the native resolution of the LCD). Image quality is best when the graphics card resolution matches the native resolution of the LCD. If your graphics card's resolution is set below that of the LCD, most LCD monitors have auto-scaling feature that stretches the image to fill the entire screen.
• Next, check the refresh rate of the graphics card (also known as vertical sync, screen refresh) set to 60Hz.

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In an LCD, each pixel corresponds to a specific set of red, green, and blue LCD cells. When an LCD monitor gets an analog signal, it has to decide which cell is supposed to display a specific pixel. If it can't make up its mind, the pixel will jump back and forth between adjacent sets of cells, creating an annoying jitter in the display. LCDs have built-in controls to minimize or eliminate the problem:

• Look for an "automatic" adjustment feature that will eliminate the jitter, and adjust image size and position at the same time. The feature may be available as a button on the control panel (often labeled Auto) or as a choice in the on-screen display (OSD).
• If the monitor does not have an automatic adjustment feature, or the feature doesn't stop the jitter completely, you'll have to adjust the settings manually. Start by adjusting the coarse timing for the LCD, which should be an available setting in the onscreen display (OSD). Typical names for this feature are Clock and Tuning. Increase or decrease the setting until you have minimized the jitter you see in the image. Next, you may also adjust the fine timing for the LCD. Typical names for this adjustment are Phase and Fine Tuning.

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Imperfections may appear on the screen if either the pixel or sub-pixel is stuck always ON; a bright spot on a dark background, or it is stuck always OFF; a dark spot on a bright background. The criteria for replacement of LCDs with defective pixels depends on the manufacturer of the LCD. Use the following as a guideline to see if your LCD is defined as "defective" and possibly replaceable through your manufacturer.

The LCD meets one of the following criteria:

• a total of 15 stuck sub-pixels or 10 stuck full pixels
• 10 stuck red sub-pixels
• 10 stuck blue sub-pixels
• 4 stuck green sub-pixels
• No more than two "adjacent" pixels may be stuck, adjacent being defined as less than 2.5mm edge to edge
• No more than two pairs of two-adjacent stuck pixels per display

note: A pixel (picture element) consists of one red, one green and one blue sub-pixel. A stuck green sub-pixel is more visible than blue or red.

Related topics:

• Dead-pixel white paper (pdf file format)

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Your wide screen LCD may be using automatic scaling to stretch video images at 4:3 aspect ratio to fill the entire 16:9 aspect ratio screen.

• If you're viewing a TV/VCR image, use the on-screen menu to select 4:3 aspect ratio.
• If your LCD is displaying a computer image and your video resolution is set at a 4:3 aspect ratio resolution such as VGA (640 x 480), SVGA (800 x 600), or XGA (1024 x 768), the LCD uses auto-scaling stretching the image to fill the entire screen. You may want to get a video card that supports the native resolution of your LCD.

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