Abstract: An improved interferometric apparatus is disclosed which enables the accurate measurement of variations in surface displacement. The interferometric apparatus is coupled to a vibrating piezoelectric crystal which may be oriented to detect a parameter that causes movement of the crystal. By comparing a reference signal generated by the interferometer in the absence of any parameter affecting the piezoelectric crystal, the magnitude of any parameter thereafter affecting the piezoelectric crystal can be easily and accurately determined by the interferometer output. The combination may therefore be used to provide inexpensive and low power laser gyroscopes and similar structures which may be employed to sense rate, acceleration and other parameters in electronic systems.

Abstract: A brilliant liquid crystal display having the capability of a wide variety of coloration is disclosed utilizing a photoluminescent transflector for concentrating the internal light and ambient light into a narrow frequency range which is coordinated with the dye selected for the liquid crystal, resulting in an enhanced brightness for the display. Masking all regions of the liquid crystal display except for the selectively annunciating segments thereof, the resultant display is capable of a broad range of colors having a significantly enhanced luminance characteristic.

Abstract: A liquid crystal display (LCD) system and technique is disclosed which enables an improved visual presentation and display of the rate of change of an aircraft parameter in an avionics system. The rate of change of the parameter is computed and its magnitude is used to generate a frequency proportional to that magnitude. The generated frequency is coupled to control circuitry which energizes a plurality of display elements to sequentially and cyclically produce a visual display of those elements at a repetition rate proportional to the generated frequency. The display elements are separated into two groups, one of which indicates the rate of change during one condition of the parameter, and the other of which indicates the rate of change during another condition of the parameter. The display elements are located in groups above and below a digital display of the aircraft parameter. In this manner, the rate of change of a given parameter can be easily perceived even with peripheral vision.