| 摘要 |
A cross-over field-of-view composite Fresnel lens for use in an infrared detection system includes a plurality of Fresnel lens segments provided in first and second groups. The first group of Fresnel lens segments are constructed as grooves-in lens segments and arranged in the array as grooves-in lens segments (or, alternatively, are constructed as grooves-out lens segments and arranged in the array as grooves-out lens segments). The second group of the Fresnel lens segments are constructed as grooves-out lens segments but arranged in the array as grooves-in lens segments (or, alternatively, are constructed as grooves-in lens segments but arranged in the array as grooves-out lens segments). This combination results in an array of Fresnel lens segments wherein the lens segments of the first group pass the incident energy without refraction of the fields-of-view thereof whereas the lens segments of the second group refract the fields-of-view of the incident energy, causing cross-over of the fields-of-view of the lens segments G and H of the second group with the fields-of-view of adjacent ones of the lens segments A-F of the first group and resulting in the array of Fresnel lens segments having an expanded composite field-of-view compared to an array of Fresnel lens segments without the cross-over of fields-of-view.
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