Current commercial touch-screen applications rely solely on visual cues for positive confirmation of an intended task. The visual interaction that is required (with the system) draws the operator's focus away from the primary task at hand, i.e. control of a machine or instrument. The added workload on an operator compromises the benefits provided by the application of a touch-screen. Displays used in a cockpit typically have a bezel around the perimeter with mechanical switches for operator interaction.

Electromechanical switches have low reliability and are fixed format. Any change to the bezel functionality requires a complete redesign at considerable cost.

In an effort to improve man-machine interaction and system reliability, Interface has developed a patented display with a tactile touch-screen. This combination restores the sensory perception of both visual and tactile feedback typically provided by an electromechanical pushbutton. The combination of tactile response and touch-screen technologies allows the full benefit of a multi-function display to be realized and reduces overall operator workload.

Design Concept

The design for a tactile touch-screen display unit utilizes a COTS Active Matrix Liquid Crystal Display (AMLCD) with touch-screen overlay.

Actuators are incorporated in the design to provide tactile feedback. The layout of function switches or touch keys and their position and dimensions, is accomplished through software. An added feature in the software includes reverse contrast to exhibit an extra visual signal that the switch is electronically actuated. Another design feature, coincident with the tactile forced feedback, is an audible click that is comparable to a click from a mechanical switch.

A completed unit comprises of a COTS AMLCD with touch-screen overlay with controller board, actuators and driver board and single board computer in a ruggedized package. In addition, field programmable software allows for reconfiguring touch keys without changing hardware, thus building flexibility. Programmable pages can be added to provide multi-tasking capability within one display thus reducing the number of displays needed. Additionally, keys can be color coded or highlighted for system interface cuing.

A display with tactile touch-screen may be used on a number of man-machine interface platforms ranging from avionics to marine control centers, command and control centers and ground-based systems, which include maintenance and simulator systems.