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ERIC Number: ED048764
Record Type: RIE
Publication Date: 1970-Jun
Pages: 35
Abstractor: N/A
Reference Count: N/A
Selection of Rear Projection Screens for Learning Carrels.
Smith, Edgar A.
The selection of a rear projection screen for a learning carrel should take into account the viewing angle involved. In some carrels, the viewer can be seated in front of the screen (i.e., on the normal axis) since the screen is used primarily to present information. In these cases, where the screen will be viewed only from a restricted range, a highly directional screen may be employed since such a screen only disperses light to a small area so that the light is highly concentrated. This condition is usually favorable in terms of operational economics, reliability, heat generation, noise level, and maintainability. In other carrels, the learning situation may require that the viewer be mobile and so it cannot be assumed that he will view the screen from the best angle. In other words, the learning task controls the choice of screen. To facilitate the matching of learning requirements with screens, 21 commercially available screens were evaluated using a goniophotometer. The resulting measurements are presented in a normalized fashion which allows the user to compare screens in terms of light distribution and relative normal axis readings. Readings at angles where light falls off to 50 percent and 25 percent are also given. (Author/MT)
National Technical Information Service, Springfield, Virginia 22151 (AD-717 713, MF $.95, HC $3.00)
Publication Type: N/A
Education Level: N/A
Audience: N/A
Language: N/A
Sponsor: N/A
Authoring Institution: Air Force Human Resources Lab., Brooks AFB, TX.