| To design a video system correctly, it is necessary to identify the optimal screen size for every single application. Specific conditions of the projection environment may require a very specific screen dimensions (width and height). With Adeo this option is possible, subject to the respect of geometrical parameters and the need to retain the quality of the final projection. To make the size of the screen independent from the chosen aspect ratio, the screen’s height (H) is considered. Unlike the screen’s width (W), its height remains the same regardless of the aspect ratio chosen. The first step in optimal screen size calculation is selection of the type of installation: professional or home cinema.
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1.- PROFESSIONAL INSTALLATIONS.
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For professional installations three variables must be considered to obtain the best viewing results: - the distance (D) between the screen and the least favoured viewer (LFV),
- the type of application: if the screen is used mainly for PC presentations or for graphics/tables/drawings.
- the aspect ratio.
To obtain the height (H) of the screen, just calculate the distance between the screen and the LFV and divide it by 6 for PC presentations or by 4 for graphics/tables/drawings. |
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The respective width (W) of the screen is obtained by multiplying the resulting height (H) by the chosen aspect ratio: 1.33:1 (‘Academy’ format 4:3), 1.25:1 (5:4), 1.6:1 (16:10), 1.78 (16:9 format used mainly for HDTV), etc.
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| 2.- HOME CINEMA INSTALLATIONS. |
For home cinema applications, the “Ds” stands for the distance between the screen and the main viewing position or “Sweet Spot”. To calculate the height of the screen, take Ds and divide it by 3.3 if the home theatre system has a HD resolution or an upconverted SD resolution. For home theatres with Full HD resolution, divide Ds by 2.5 .
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The respective width (W) of the screen is obtained by multiplying the resulting height (H) by the chosen aspect ratio: 1.33 (‘Academy’ format 4:3), 1.78 (16:9 format used mainly for HDTV), 1.85 (Wide Screen), 2.05 (70mm format), 2.35 (CinemaScope format), 2.40 (Panavision), 2.76 (Cinerama format), etc.
Depending on the application, it is possible to design a home cinema installation with a “sweet spot” area optimized for Full HD resolution (1.080p) and the second row optimized for HD resolution (720p). |
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SUGGESTIONS FOR BETTER VISION.
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In order to enjoy the best performance from your video system, please take into consideration these suggestions: a) VISUAL RESOLUTION:
The visual resolution must be appropriate for the image size, view task, and viewer distance from the screen.
As the screen is set further away from the viewer, the screen size must be larger to maintain visual resolution.
Take note also that the smallest character height that can be resoled is 1/150 times the distance to the screen. b) HEIGHT OF AND DISTANCE FROM THE IMAGE:
In order to avoid unpleasant vision due to excesive geometric distorsions, the screen has to be positioned far away from the nearest viewer at a distance of, at least, 1 x Screen Width.
It is important also to determine that the visual angle between horizontal line and the line made from the eyes of the nearest viewer and the center of the screen should be no more than 15° in order to allow a comfortable head posture also for the first line viewers.
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c) SCREEN GAIN:
High-gain projection screens can limit viewing angles, since these screens are more directional, focusing the projected light along the axis of the projector.
The gains of Adeo screen’s surfaces are: d) VIEWER’S ANGLE FROM THE SCREEN:
A room can usually be divided into good and acceptable viewing areas. The good viewing area is within 45° of the projection axis, creating a 90° “viewing cone” oriented on the center axis of the screen. The acceptable viewing area is within 45° of the edge of the image. |
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