XX can be used to project important information of flight and battlefield in front of the pilot and overlaid on the scene outside. Meanwhile, YY don’t have to fly the FJ point to the enemy planes before launching the off-Boresigt missiles assisted by the line of sight measurement components, so as to aim enemy planes and strike them earlier.
According to the principle of geometric optics, the improvement of traditional XXs’ performance has to increase its weight and volume. Pilots have suffered from traditional XXs for a long time, owing to heavy burden on their necks result from XXs’ weight. In addition, pilots can’t get display information when overload maneuver result from the small exit pupil. Holographic waveguide display technology takes advantage of the successive diffractive light decomposed of holographic diffractive gratings, which can be used to flatten and lighten the optical system. It is the trend of XXs’ technology development in the future. However, the holographic waveguide XX technology is focus on small exit pupil and monochromatic at present, with the result that they can’t provide excellent XXs with larger exit pupil. In addition, it is not good for reducing pilots’ reaction time only by monochromatic symbol. The key technology research on larger exit pupil, bi-color holographic waveguide XX carried out in this thesis and the main work is as follows:
The mathematical model of holographic waveguide XX was build centered by energy distribution on the exit pupil, and the performance evaluation method for large exit pupil display based on the intensity distribution was put forward. The relationship between system’s critical optical performance and parameters was identification. It can give good guidance for optical design and holographic waveguide exposure.
A method for improving the angular width of holographic waveguide gratings was put forward, which figure out the problem of field of view. The angular width has been expand more than three times. In addation, the continuity equation which resolve the problem of energy dissipation was brought forward, and the black gap has been eliminated which result from large diffraction angles of margin light.
The design approach called equivalent wavelength which can give a good solution for optical design software to trace light rays by rule and line was put forward. The accurate ray tracing was realized in this way. A design example of a bi-color optical system holographic XX used for displaying green and red information was presented. Its field of view is 30 degree (circular), and its exit pupil is Φ30mm. The design result of the system has a comparable level with BAE Q-Sight 150.
Besides, a wavelength equivalent exposure method with a conjunct light path was put forward, and the exposure of red holographic waveguide element was achieved with the same argon laser. In this way, the problem that dichromate gelatin was not sensitive to red light was solved. Meanwhile, the vibration has no effect on gratings during its exposure.
In order to solve the problem that the diffraction efficiency of the holographic waveguide element cannot be directly measured and the results of the transmission test were inaccurate, the secondary diffraction testing method was proposed. At last, the test optical path was designed and the test results were given, too.
According to the guidance of theoretical research, a bi-color XX prototype has been developed, and the research has reached the leading level in China. After assembling and aligning, the typical performance, such as exit pupil, field of view and brightness were tested, which demonstrate the correctness and rationality of the system mathematical model, optical design method and the exposure method of holographic waveguide elements.