Flight Dynamics, Inc.

Thomas E Hodel

Robert B Wood

Mark A Thomas

Robert E Stockwell

A head up display system includes a combiner alignment detector (24) that determines whether the combiner (22) and a cathode-ray tube (CRT) (18) are aligned within a preassigned operational tolerance. The CRT emits display symbology that reflects off the combiner toward an observer. The combiner is secured to a combiner bracket (38) which is pivotally mounted to a mounting structure (70) having a stationary relationship with the CRT. A light emitting diode (LED) (86) and a light-sensitive linear position detector (88) are secured to the mounting structure. Light rays emanating from the LED are reflected by a mirror (34), which is secured to the combiner bracket, and strike the position detector. Pivotal motion of the combiner bracket relative to the mounting structure results in movement of the mirror relative to the LED and the position detector. The pivotal motion of the mirror causes light reflected by the mirror to strike varying locations on the position detector, which provides corresponding output signals. A processing circuit (110) receives the signals provided by the detector and provides to a control circuit (129) a signal corresponding to the alignment of the combiner and the CRT and to the position of the display symbology reflected by the combiner. The control circuit provides a warning signal whenever the information provided by the processing circuit indicates that the display symbology is not located at a preselected position.

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Beaverton, OR, United States of America

Thomas E Hodel