A switch panel having a touch plate, image generator, imaging system and light source is disclosed. The touch plate includes an optically transparent layer having first and second surfaces in which a light signal is trapped by internal reflection. The image generator displays an image that includes a plurality of button positions to a person viewing the touch plate from the first surface. When the user touches the front surface at one of the button positions, light from a multi-LED light source that generates the trapped light signal is caused to escape the touch plate at a point corresponding to the point of contact. The light leaving the touch plate is imaged by the imaging system and used to determine the location of the point of contact. Images taken with different LEDs in the light source are used to make the contact determination to reduce the effects of ambient light. |