Video and displays
Ultra short throw (UST)
A projector design with a throw ratio below about 0.4 that sits inches from the wall and projects steeply upward onto the screen.
An ultra short throw projector uses a wide-angle mirror or lens to throw a large image from a cabinet placed directly beneath the screen. Typical throw ratios are 0.19 to 0.25, so a 100 inch picture comes from a unit sitting roughly 20 to 30 cm from the wall.
The layout removes ceiling mounts, long cable runs, and shadows from people crossing the beam, which makes projection practical in living rooms. The steep angle, however, makes the image very sensitive to screen flatness.
Because light arrives from below at a shallow angle, a UST projector pairs best with a lenticular ALR screen built for that geometry. A standard matte screen or a ceiling-mount ALR screen will look washed out or uneven.
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