Georgia Tech Research Institute

Displays: Issue 3 of 6

Issue: Parallax may be a problem for seated users.

Certain display and control configurations (for example, an inset display screen surrounded by soft keys) are susceptible to parallax errors. On-screen key labels are designed to align with the location of bezel keys when viewed from a certain angle (e.g., when standing in front of the display). When viewed from a different angle (e.g., when seated in front of the display), the parallax error causes misalignment between the labels and the keys, making it difficult to tell which label goes with each key.

Populations Impacted: Users with lower mobility impairments.

Potential Solutions:
  • Place the display and the soft keys on the same plane. If the display and the soft keys are coplanar, parallax errors are eliminated.

  • Provide an adjustable angle display. If the vertical tilt angle of the panel containing the display and the soft keys is adjustable, users can reposition the screen to eliminate parallax errors.

  • Provide guide lines from soft keys to the edge of the display to provide additional visual association cues. Guide lines can visually "connect" soft keys to their on-screen labels, allowing users to follow the guide lines to determine the appropriate key to press.

Applicable Guidelines:
ADA-ABA - 707.7.1