US 11,796,796 B2
Off-axis two-mirror infrared imaging system
Wei-Chen Wu, Beijing (CN); Jun Zhu, Beijing (CN); Guo-Fan Jin, Beijing (CN); and Shou-Shan Fan, Beijing (CN)
Assigned to Tsinghua University, Beijing (CN); and HON HAI PRECISION INDUSTRY CO., LTD., New Taipei (TW)
Filed by Tsinghua University, Beijing (CN); and HON HAI PRECISION INDUSTRY CO., LTD., New Taipei (TW)
Filed on Jun. 2, 2021, as Appl. No. 17/337,224.
Claims priority of application No. 202010818309.7 (CN), filed on Aug. 14, 2020.
Prior Publication US 2022/0050288 A1, Feb. 17, 2022
Int. Cl. G02B 27/00 (2006.01); H04N 5/33 (2023.01)
CPC G02B 27/0018 (2013.01) [G02B 27/005 (2013.01); H04N 5/33 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An off-axis two-mirror infrared imaging system, comprising:
a primary reflecting mirror located on an incident light path of an incident infrared light beam, wherein the primary reflecting mirror reflects the incident infrared light beam to form a first reflected light beam; and
a secondary reflecting mirror located on an reflection light path of the primary reflecting mirror, wherein the primary reflecting mirror reflects the first reflected light beam to form a second reflected light beam, and the second reflected light beam reaches an image surface after passing through the incident infrared light beam;
wherein a space where the off-axis two-mirror infrared imaging system is located is defined as a global three-dimensional rectangular coordinate system (X, Y, Z), a space where the primary reflecting mirror is located is defined as a first local three-dimensional rectangular coordinate system (X′, Y′, Z′), a space where the secondary reflecting mirror is located is defined as a second local three-dimensional rectangular coordinate system (X″, Y″, Z″); the first local three-dimensional rectangular coordinate system (X′, Y′, Z′) are obtained by translating the global three-dimensional rectangular coordinate system (X, Y, Z) along a negative direction of a Y axis and a positive direction of a Z axis, and the second local three-dimensional rectangular coordinate system (X″, Y″, Z″) is obtained by translating the first local three-dimensional rectangular coordinate system (X′, Y′, Z′) along the positive direction of the Y axis and the negative direction of the Z axis; reflective surfaces of the primary reflecting mirror and the secondary reflection are freeform surfaces; the secondary reflecting mirror and the image surface are respectively located on both sides of the incident infrared light beam, so that the incident infrared light beam is between the secondary reflecting mirror and the image surface; and a focal length of the off-axis two-mirror infrared imaging system is in a range from 120 mm to 160 mm, and F number of the off-axis two-mirror infrared imaging system is in a range from 1.4 to 2.0.