R5976255
A
TLAS
CS4 (2001-03)
13-6
13.3 Viewing Distance and Ang le
When planing the installation of A
TLAS
CS4, anthropotechnical factors such as the human field of
vision must be considered in addition to design requirements. General rules for the viewing angle
and distance will not be specified here since they depend on the field of application. The notes in
this section are therefore only recommendations which can be observed for a particular applica-
tion.
In the case of permanent, intensive viewing of the display, the display should be in the field of vi-
sion of both eyes of the observer. The following figure shows the horizontal and vertical angles of
the field of vision with both eyes. An optimum field of vision can be defined for the horizontal
field.
Figure 13-5
Human field of vision for both eyes
The maximum viewing distance depends on the minimum character size used. Characters and up-
per-case letters should appear to the eye at an angle of vision greater than 18 angular minutes. This
corresponds to a viewing distance less than 200 times the character height.
Viewed objects
Image
on retina
Angle of vision
Figure 13-2
Angle of vision
