Pros and cons of HTPS projectors
HTPS projectors present several advantages and disadvantages when compared with the DMD-based projector. The advantages include:
● Better colour saturation: Since HTPS projectors use three RGB panels, colours tend to be rich and vibrant.
● Sharper image than equivalent resolution DLP systems, whose tilted mirror pixels can appear blurred at the corners.
● The 3-panel HTPS provide a higher lumen output than single-panel DLP projectors with the same wattage lamp.
● Mature technology.
The disadvantages of HTPS projectors include:
● Screen door effect: As was explained earlier, the black matrix TFT element that is necessary in HTPS panels creates visible pixilation known
as the screen door effect. Several measures have been taken to alleviate this effect. The first one is through increased pixel count. A WXGA projector has over 1 million pixels while a VGA panel has only 300,000 pixels. Second, reducing the inter-pixel gaps. A third development is the use of microlens arrays (MLAs; Figure 19.9). Though developed primarily to boost efficiency, the MLA concentrates light through the pixel aperture thus de-emphasising the sharp pixel edges.
● Relatively low contrast: System contrast is difficult as a result of the field of view (FOV) of the TN LCD mode.
● Lifetime: LC alignment layers used in HTPS LVs are organic polyimides which are susceptible to UV and deep blue light photochemical damage, which reduces operation lifetimes. UV filters with a long-wavelength cut-off are helpful but tend to reduce the blue content of the final colour images.