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2 LED Backlight Redundancy The Day and Night LEDs are structured in a way that any loss of a single element will not cause any string of devices to be disabled. Any loss of luminance due to a single or multiple elements will be compensated by the optical sensor closed loop mechanism. This topology consists of two sets of power invertors for the RGB Day/ Night LEDs and sets of control logic with monitoring circuitry that detects any deviation or loss of signals or power. The appropriate channels, the drive power and controls, are then routed to the Day/Night LEDs. In addition, redundancy is also established for the light sensors and temperature sensors. Figure 4 shows block diagram of the Backlight Redundancy. Figure 4. Backlight Redundancy Block Diagram Cost Advantages over Custom Large Area Displays The envisaged cost advantages bogey of this proposed architecture is $10-15K per display head assembly. The cost of adding new part number to a typical military supply chain inventory is about $2M, based on 50 years of personal observable experience. The break point for custom glass verses this approach is 134 to 200 displays. Canopy Reflections Solutions Bubble canopy aircraft are subjected to stray light from cockpit displays, specifically from large area displays. The reflected stray light from the canopy cause secondary images to be formed on the canopy at low light operational environments. This can cause a great deal of interference during mission fulfillment at low ambient flying scenarios. The challenge is to attenuate the stray light from the display outside the specified pilot head box thereby minimizing problematic canopy reflections. There are many way of eliminating the stray light emitted, amongst these are light pipes and prismatic films to control light emitted from the display outside the field of view. Figure 5 shows simulation of the uncontrolled stray light flooding a typical bubble canopy cockpit. Figure 6 shows the pilot eye prospective of the cockpit at primary viewing angle where canopy reflections can be seen as secondary images reflected from the canopy. With the implementation of the emitted stray light control, light is no longer flooding the entire cockpit which prevents canopy reflection as seen in Figure 7. Complete elimination of canopy reflection from the pilot eye perspective of the cockpit is shown in Figure 8. Figure 9 shows typical Headbox Specification. Controlled sharp cut-off implementation is shown in Figure 10 where the horizontal and vertical response is controlled precisely at the specified cut-off angles. Figures 11 and 12 depict ELDIM plots of display light output with and without stray light control.

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