Vehicle head-up display systems

A head-up display system for a vehicle comprising:

• a. a semi-reflective combiner element adapted to be installed in the vehicle on the line of sight of an observer in the vehicle of a scene outside the vehicle;
• b. a display surface;
• c. activating means operable to activate substantially any portion of the said surface so as to cause the said portion to emit light;
• d. between the combiner element and the display surface a collimating optical system which, when a display is present on the display surface as a result of activation as aforesaid, projects a collimated image of the display to the combiner element for reflection to the observer's eyes, thereby effectively superimposing the image of the display on the observer's view of the outside scene through the combiner;
• e. a waveform generator responsive to input data signals derived from sensors carried by the vehicle and representing the relationship of the vehicle to its environment so as to repetitively develop a time sequence of output signals capable of being employed for controlling the activating means to activate desired line segments of the display surface thereby to present at said surface symbols representative of the aforesaid relationship;
• f. a signal source operable to develop a raster scan output signal representative of the environment sensed by an imaging sensor;
• g. a symbol storage device operable in response to output signals from the waveform generator so as to store symbols to be presented at the display surface;
• h. a symbol read-out arrangement operable to develop a raster scan output signal representative of the symbols stored in the symbol storage device, said output signal having the same format as the signal source output signal;
• i. signal combiner circuitry operable to receive the output signals from the signal source and the symbol read-out arrangement so as to develop a raster scan output signal representative of both said symbols and said environment;
• and
• j. means for connecting either the output of signal combiner circuitry or the output of the waveform generator to the activating means.