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Fuzzy Display / Shimmer on TFT Monitors

If your TFT display is fuzzy or has a “shimmer” there are four possible causes:

Refresh Rate Set Too High

Unlike CRT (cathode ray tube) monitors, TFT (thin film transistor) displays do not respond to faster refresh rates by the video adaptor to achieve a smoother display. For example, a CRT monitor with a low refresh rate can produce a noticeable flicker which can be irritating. Monitors can operate at different refresh rates to accomodate the capabilities of your computer and your personal preference.

However, TFT displays are designed to operate optimally at a particular refresh rate (generally 60Hz) and using a different refresh rate will result in a fuzzy display.

To change the refresh rate, right-click on an empty part of the desktop, choose Properties, click on the Settings tab and then click Advanced.

Windows XP ClearType

Windows XP introduces a new technology called ClearType which smooths the appearance of fonts by exploiting the way pixels are arranged on TFT displays. Whereas various versions of Windows (since Windows 95) have been able to “smooth” font appearance on CRT and TFT displays, ClearType significantly improves the readability of fonts. However, some people find ClearType to be indistinct.

ClearType can be optimised to your personal preference by using the online ClearType tuner:

If you find that ClearType cannot be tuned to your liking, it can be turned off:

  1. Right-click on an empty part of the desktop and choose Properties;

  2. Click the Appearance tab;

  3. Click Effects;

  4. Set “Use the following method to smooth edges of screen fonts” to Standard;

    — or —

    Uncheck “Use the following method to smooth edges of screen fonts” to disable all font smoothing.

  5. Click OK to close the Effects dialog;

  6. Click OK to close the Display Properties dialog.

Wrong Display Resolution

Like CRT monitors, TFT displays can operate at many resolutions. However, unlike CRT displays, only one resolution is optimal. For example, a 15″ TFT display typically is designed to operate at 1024×768. If you operate at a lesser (800×600) or greater (1200×1024) resolution, the video driver must interpolate the pixels to the screen's native resolution, and this is slower and fuzzier.

Interference from AC Adaptor

Modern notebooks use a 3-pin AC adaptor, with the third being earth. The earth cable interferes with TFT displays which do not have sufficient shielding. Moving the AC Adaptor away from the monitor may reduce the shimmer effect. This may be tested by running the notebook on battery to determine if the shimmer stops.

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