Helmet mounted display device

A helmet mounted display device including an opaque display element arranged to be mounted on a helmet visor outside of a wearer's usual instantaneous field of view and a display control circuit disposed remotely from the display element and coupled thereto by signal transmission apparatus.

FIELD OF THE INVENTION 
The present invention relates display systems generally and more 
particularly to helmet mounted display systems. 
BACKGROUND OF THE INVENTION 
Various types of helmet mounted display systems are known in the art. In 
recent years helmet mounted head-up displays have been developed and allow 
images to be displayed in overlay over the wearer's view of the outside 
world. Generally speaking head-up displays are relatively expensive and 
heavy and must be specially designed for each given helmet. 
SUMMARY OF THE INVENTION 
The present invention seeks to provide a simplified helmet mounted display 
system. 
There is thus provided in accordance with a preferred embodiment of the 
present invention a helmet mounted display device including an opaque 
display element arranged to be mounted on a helmet visor outside of a 
wearer's usual instantaneous field of view and a display control circuit 
disposed remotely from the display element and coupled thereto by signal 
transmission apparatus. 
In accordance with a preferred embodiment of the present invention, the 
opaque display element includes an optical element which makes the display 
appear to the wearer as if it lies at infinity, so as to obviate the need 
for the wearer to refocus his eyes in order to read the display. 
Additionally in accordance with a preferred embodiment of the present 
invention, the display element is mounted on the outside of a transparent 
visor. 
In accordance with a preferred embodiment of the invention, the display 
element is removably mounted on the visor. 
Further in accordance with a preferred embodiment of the invention, the 
transparent visor is retractable and the helmet is formed with a recess 
for accomodating the display element when the visor is retracted.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
Reference is now made to FIGS. 1-2B which illustrate a helmet display 
system constructed and operative in accordance with a preferred embodiment 
of the present invention. 
The helmet display system comprises control circuitry 10, which may be 
similar in all relevant respects to conventional, commercially available 
control circuitry for helmet mounted head-up displays. Control circuitry 
10 receives input information from a system to be monitored, such as an 
aircraft or any other airborne system and provides a display output via 
signal transmission apparatus, which is preferably a flexible conductor 
12. 
In the illustrated preferred embodiment, the conductor 12 terminates at a 
coupling member 14, which is mounted on a helmet 16. Coupling member is 
flexibly connected, via a conductor 18, to a display element 20, which, as 
seen in FIGS. 2A and 2B is preferably mounted at a location on a 
transparent helmet visor 22, which is outside the normal instantaneous 
field of view 24 of the wearer. 
As seen in FIG. 2B, the display element 20 preferably comprises a housing 
26 in which is disposed a display 28, such as a LCD display, for example a 
240.times.648 element, 0.96 diagonal active matrix color LCD, available 
from Citizen Watch Company of Japan or a 324.times.220 element 0.9 inch 
diagonal active matrix black and white LCD available from Matsushita of 
Japan, or any other suitable display. An optical element, such as a 
collimating lens 30, is provided to cause the display 28 to appear to the 
wearer as at infinity. 
In accordance with a preferred embodiment of the present invention, the 
helmet 16 is formed with a recess 40 for accomodating display element 20 
when the visor 22 is retracted. 
It will be appreciated by persons skilled in the art that the present 
invention is not limited by what has been particularly shown and described 
hereinabove. Rather the scope of the present invention is defined only by 
the claims which follow.