Flight training glasses

DETAILED DESCRIPTION In one principal aspect, the present invention is an improved position sensor.
The improvement includes a pair of directional photocells and comparator circuitry for interconnecting the directional photocells with the ambient photocell and for providing an opaquing signal under predeterminded conditions.
In response to the opaquing signal, the voltage-controlled lens switches to the opaque state.
An inherent disadvantage of the instrument flight training glasses disclosed in the Witt patent, becomes evident during use in cockpits wherein the windshield is divided by a vertical support strut.
If, as the student pilot raises his head, the single directional photocell is focused onto the support strut, the position sensor may not respond in the proper fashion, such that windshield vision is permitted rather than prohibited.
The improved position sensor substantially avoids this deficiency.
The two directional photocells are oriented such that their operational axes are non-parallel.
With this orientation or configuration, focus upon a single point or object within the cockpit is substantially avoided.
In another principal aspect, the present invention is an improved lens configuration.
With the training glasses disclosed in the Witt patent, the student pilot can, by slight rotation of the head about a vertical axis, obtain substantial peripheral vision through the lower voltage-controlled lens portion.
The improved lens configuration includes a vision-restricting portion and a voltage-controlled portion, which cooperatively define a viewing window in the lower, inner quadrant of the lens.
In other words, the two portions define a boundary therebetween having a vertical component and a horizontal component.
The vertical boundary component prohibits peripheral vision without a major head turn.
With such a head turn, the directional photocells will sense an increase in light and opaque the viewing window.
In a third principal aspect, the present invention includes a voltage-controlled lens portion defining a window in the lower, inner quadrant and means are provided for selectively enlarging the viewing window