This paper is a response to the challenge of providing a large area avionics display for the E-2D AHE aircraft. The resulting display design provides a pilot with high-resolution visual information content covering an image area of almost three square feet (Active Area of Samsung display = 33.792cm x 27.0336 cm = 13.304" x 10.643" = 141.596 square inches = 0.983 sq. ft x 3 = 2.95 sq. ft). The avionics display application, design and performance being described is the Primary Flight Display for the E-2D Advanced Hawkeye aircraft. This cockpit display has a screen diagonal size of 17 inches. Three displays, with minimum bezel width, just fit within the available instrument panel area. The significant design constraints of supporting an upgrade installation have been addressed. These constraints include a display image size that is larger than the mounting opening in the instrument panel. This, therefore, requires that the Electromagnetic Interference (EMI) window, LCD panel and backlight all fit within the limited available bezel depth. High brightness and a wide dimming range are supported with a dual mode Cold Cathode Fluorescent Tube (CCFT) and LED backlight. Packaging constraints dictated the use of multiple U shaped fluorescent lamps in a direct view backlight design for a maximum display brightness of 300 foot-Lamberts. The low intensity backlight levels are provided by remote LEDs coupled through a fiber optic mesh. This architecture generates luminous uniformity within a minimum backlight depth. Cross-cockpit viewing is supported with ultra-wide field-of-view performance including contrast and the color stability of an advanced LCD cell design supports. Display system design tradeoffs directed a priority to high optical efficiency for minimum power and weight.
Volume phase gratings in photorefractive crystals have nonuniform amplitude and phase due to the energy exchanged by the writing beams within the material. Analytic expression is obtained for the diffraction efficiency of a weak reading beam that does not perturb the grating and has a different polarization from the write beams. For a read beam of arbitrary intensity, the diffraction efficiency is a nonlinear function of the read beam intensity and is nonreciprocal with respect to readout from the two input ports. These properties of photorefractive gratings are studied for arbitrary phase shifts of the index grating from the intensity pattern.
The self-pumped ring phase conjugation using reflection gratings in Kerr media is investigated. The results show that with a ring cavity, self-oscillation occurs at a certain threshold intensity which is lower than that for the conventional stimulated Brillouin scattering process. The effect of cavity detuning on phase conjugation reflectivity and frequency shift is also discussed.