HIGH-APERTURE LENS Russian patent published in 2018 - IPC G02B9/62 

FIELD: instrument engineering.

SUBSTANCE: lens can be used in digital sighting and observation devices with the images formation on the CCD or CMOS matrices under day and night conditions. First component comprises biconvex lens and negative concave-convex lens facing the image with convexity, second one is the single positive meniscus lens, facing the images space with concavity, third one is the negative meniscus lens and the positive meniscus lens, facing the image with concavity, fourth one is the negative meniscus lens, facing the image with concavity. Aperture diaphragm is located in front of the first component. Following ratios are met: d_1-2=(0.8÷2.0)⋅F_LENS, n_3-1=n₄≥2.0; where F_LENS is the lens focal distance; d_1-2 is the air gap between the first and second components; n_3-1 is the third component first lens refraction index; n₄ is the fourth component lens refraction index. As a result, enabling increase in the optical efficiency to the value of 1:0.85 with the spectral operating range extension to Δλ=(600…1,000) nm and the image quality improvement at spatial frequencies 90…100 lines/mm with polychromatic modulation transmission coefficients at the level of at least 0.4 in the field of view center and at least 0.3 at the field of view edge.

EFFECT: increase in the optical efficiency with the spectral operating range expansion and improvement in the image quality.

1 cl, 1 dwg, 1 tbl