{'fraction_non_alphanumeric': 0.017635532331809273, 'fraction_numerical': 0.0, 'mean_word_length': 4.781132075471698, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Analysis of ghost images in a compound prismatic combiner for head-up-displays

Systems of augmented reality are widely used not only in military but and in civil application. Providing a sufficient size for the pupil zone, which is the area where the user’s eye could be located, may be implemented in different ways. One of the ways is to multiply (duplicate) the pupil using a beam-splitting with special coating or elements, for example with semi-transparent layers. This method is very attractive because it can provide the most compact schemes. The compound prismatic combiner which uses waveguide principle is considered and analyzed in the work. It was shown in previous work that the angles of the entrance prism and layers should be chosen in certain limits to provide beam passing through the structure due to total internal reflection, partially reflected by beam-splitting layers. This structure has mosaic structure of the pupil zone that means appearing the dark zones where the part of an image does not exist. To minimize dark zones the structure step should be minimal but the ghost images may appear. Dark zones size and brightness of the ghosts are dependent on the combiner’s parameters, so we can find optimal case as a compromise between the dark zone size and ghost image. Analysis of the ghosts’ brightness was implemented, and optimal locations of the observer’s eye and optimal structure parameters were found from the point of view of minimizing ghosts for the system with the smallest blind zone sizes.