一种长波制冷无热化镜头

Abstract

本实用新型涉及镜头技术领域，公开了一种长波制冷无热化镜头，包括：由物侧到像侧沿光轴依次设置的第一透镜、第二透镜、第三透镜、第四透镜以及第五透镜；其中，所述第一透镜、所述第三透镜以及所述第五透镜均为正透镜，所述第二透镜以及所述第四透镜均为负透镜；所述第一透镜以及所述第二透镜均为凸面朝向像侧的弯月形透镜，所述第三透镜以及所述第五透镜均为双凸透镜，所述第四透镜为凹面朝向物侧的弯月形透镜；所述第二透镜由锗材料制成，通过设置在第二透镜后表面设置有衍射面，与第二透镜本身的材料互补，在温度变化时，通过衍射面来抵消第二透镜因材料问题导致的焦距偏移，保证焦距稳定，实现无热化。

Claims

1. A long-wave refrigeration athermalization lens, characterized in that, include: The first lens (1), the second lens (2), the third lens (3), the fourth lens (4), and the fifth lens (5) are arranged sequentially along the optical axis from the object side to the image side. Among them, the first lens (1), the third lens (3) and the fifth lens (5) are all positive lenses, and the second lens (2) and the fourth lens (4) are all negative lenses; The first lens (1) and the second lens (2) are both meniscus lenses with convex surfaces facing the image side, the third lens (3) and the fifth lens (5) are both biconvex lenses, and the fourth lens (4) is a meniscus lens with concave surfaces facing the object side. The second lens (2) is made of germanium material, and the image-side rear surface S4 of the second lens (2) is a diffraction surface, so that when the temperature changes, the focus shift caused by the lens material of the second lens (2) is dynamically compensated by the diffraction surface.

2. The long-wave refrigeration athermalization lens according to claim 1, characterized in that: The first lens (1) is made of silicon material and has an optical power of 0.

013. The object-side front surface S1 of the first lens (1) is spherical with a radius of curvature R1 of 62.729 mm. The image-side rear surface S2 of the first lens (1) is aspherical with a radius of curvature R2 of 122.804 mm.

3. The long-wave refrigeration athermalization lens according to claim 2, characterized in that: The second lens (2) has an optical power of -0.0067. The object-side front surface S3 of the second lens (2) is spherical with a radius of curvature R3 of 47.176 mm. The image-side rear surface S4 of the second lens (2) has a radius of curvature R4 of 40.063 mm.

4. The long-wave refrigeration athermalization lens according to claim 3, characterized in that: The third lens (3) is a biconvex positive lens with an optical power of about 0.

07. It is made of germanium and its front and rear surfaces S5 and S6 are both spherical with radii of curvature R5=331.809 mm and R6=48.272 mm, respectively.

5. The long-wave refrigeration athermalization lens according to claim 4, characterized in that: The fourth lens (4) has an optical power of approximately -0.06 and is made of IRG206. The front and rear surfaces S7 and S8 of the fourth lens (4) are both spherical with radii of curvature R7=14.614 mm and R8=33.965 mm, respectively.

6. The long-wave refrigeration athermalization lens according to claim 5, characterized in that: The fifth lens (5) has an optical power of 0.056 and is made of IRG206. The object-side front surface S9 of the fifth lens (5) is aspherical with a radius of curvature R9 = 110.436 mm; the image-side rear surface S10 is spherical with a radius of curvature R10 = 42.633 mm.

7. A long-wave cryogenic athermalization lens according to claim 6, characterized in that: The lens also includes a first protective window (6) and a second protective window (7). An aperture (8) is also provided close to the rear surface of the second protective window (7), and an image plane (9) is also provided behind the aperture (8).

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