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Once upon a time, it was widely accepted that LCD projectors had two major weaknesses. First, in commonly available consumer models, the pixel structure could result in the infamous "screen door effect". That is, because the wiring driving each pixel had to be routed between the pixels, the pixel spacing, or pitch, was wide enough to make the pixel grid visible at close viewing distances. The picture below shows the screen door effect on the keys of a piano.

While the picture above is an example of the screen door effect, still noticeable on the majority of LCD data projectors but greatly reduced by smooth screen technology on the latest Home Cinema models. This issue has been over played by DLP manufacturers. To clarify all projector have the screen door effect, including DLP. Yes to a lesser extent than LCD but for a mirror (used in DLP projection) to be able to move it must have space around it in exactly the same way LCD requires wiring. The fill factor of a projector panel gives only an indication of the potential screen door problem. Currently LCD panels have the lowest fill factor of 60%, DLPand LCOS (Dila, SXRD) have the highest at 93%. The screen door difference between the technologies has also been reduced by the increase in panel resolution and larger LCD panels in home cinema machines. Micro Lens Arrays have also been used to reduce the screen door and boost Lumens.

Improved Contrast Ratio

Iris control goes a very long way in resolving the contrast and black-level issues. In a camera, the iris controls the exposure in conjunction with the shutter speed. In a projector, it changes the brightness of the image on the screen. If you close down the iris in a projector, it darkens the overall image, including the darkest grays and deepest black. But the only type of iris that has been available to date in video projectors has been fixed; multiple settings are often provided , but once you make a selection, the iris size remains unchanged unless you manually adjust it.

Closing down such a manually adjustable iris will reduce the light levels in both the blacks and peak whites, but this isn't necessarily a bad thing. Reducing the average picture level on the screen with the iris may improve the overall image by deepening the blacks, thereby reducing the grayish, washed-out effect of an absolute black level that is too high, without sacrificing adequate punch in brighter scenes. For this to work, of course, the light output of the projector must be high enough that the overall dimming effect of the stepped-down iris is tolerable.

Advanced Iris dynamically adjusts the iris to suite the scene. That is, it closes down automatically on dark scenes to provide darker blacks, and opens up on bright scenes to make optimum use of the projector's available light output. This has raised the contrast ratio to levels never before seen on an LCD of 2000:1 to 12000:1.

LCD Panels

In 2006 the manufacturer of DLP, Texas instruments, tested the durability on LCD panels by running the best Home Cinema machines 24/7 for 3 months. At the end of this test they concluded that the Organic material used in LCD panel gets damaged from the heat generated by the projector lamp. This results in discolouring of the panel to amber.  This has led to the development of inorganic LCD panels. One such technology is BrightEra . Developed by Sony BrightEra microdisplay devices are LCD devices that employ an inorganic alignment film and new LCD materials.

 This inorganic alignment film and new LCD materials are original technologies developed to achieve the high picture quality and high durability of the reflective LCOS type LCD projectors. Current high-brightness projectors generally use LCD materials that are advantageous for increasing brightness, and the optimum organic alignment film (polyimide) for aligning these LCD materials. One thing to note is the effect of panel size. Larger LCD panels are less prone to the deterioration because the UV light is spread over a larger surface area. 

Smooth Motion

3 LCD technology does not suffer from the DLP Rainbow Effect, this is most noticable when watching fast moving action see the example below