Knob design for a rotary encoder

Abstract

A rotary encoder of a control surface has a display. The display includes a ring of light emitting elements, such as light emitting diodes (LEDs), in the control surface around the shaft and knob of the rotary encoder. The rotary encoder has a shaft that rotates about an axis under control of an operator. The rotary encode has an output providing a signal indicative of the rotational movement of the shaft. A knob engages the shaft and is used by the operator to rotate the shaft. The knob, in general, has a narrow stem that engages the shaft of the rotary encoder and extends away from the control surface, and a top portion which the operator manipulates to turn the knob. The stem has a substantially circular cross-section, in a plane perpendicular to the axis of the shaft of the rotary encoder, with a narrow diameter. Similarly, the top portion has a substantially circular cross-section, in a plane perpendicular to the axis of the shaft of the rotary encoder, with a diameter larger than the diameter of the shaft cross-section. The narrow stem may have a cylindrical shape. The top portion may have a spherical shape and may be substantially rotationally symmetrical in a plane perpendicular to its axis, i.e., when viewed from the top. The knob and the shaft may be metalized to provide touch sensitivity. The top portion may include a rubber insert that protrudes around its circumference. The narrow diameter of the stem minimizes the obstruction of the view of the ring of light emitting elements. The size and texture of the top portion of the knob provides a good grip, feel and tactile response for the operator.