A high-magnification anti-radiation zoom lens

Abstract

This invention relates to a high-magnification, radiation-resistant zoom lens, solving the problems of excessive lens elements and low zoom magnification in current zoom lenses. The invention includes an object-side lens, a zoom lens group, and an image-side lens group sequentially arranged along the optical axis along the light propagation direction. The object-side lens is fixedly disposed in the object space, and the image-side lens group is fixedly disposed on the imaging focal plane. The zoom lens group includes a movable first zoom lens group and a second zoom lens group. The first zoom lens group includes a second, third, and fourth lens group sequentially arranged along the light propagation direction with their relative positions unchanged. The second zoom lens group includes a fifth and a sixth lens group sequentially arranged along the light propagation direction with their relative positions unchanged. The distance between the fourth and fifth lenses is movable. The image-side lens group includes a seventh and an eighth lens group sequentially arranged along the light propagation direction. An aperture stop is disposed between the sixth and seventh lenses.

Description

Technical Field

[0001] This invention relates to optical imaging technology, and more specifically to a high-magnification, radiation-resistant zoom lens. Background Technology

[0002] Due to the radiation effects in a nuclear radiation environment, the optical glass of ordinary camera lenses exposed to nuclear radiation will develop color centers, causing browning of the lens and severely reducing its light transmittance, thus preventing it from forming images properly. Therefore, radiation-hardened lenses are needed in nuclear radiation environments. However, most existing radiation-hardened lenses are fixed-focus lenses or low-magnification zoom lenses with a zoom ratio of 3x or less, with very few radiation-hardened zoom lenses exceeding 5x. Furthermore, zoom lenses generally have more than 11 elements, making their structure complex, manufacturing and assembly time-consuming and labor-intensive, and costly. An excessive number of elements also does not necessarily improve the lens's radiation resistance.

[0003] Existing anti-radiation zoom lenses are typically limited by the available glass materials, usually having more than 11 elements. Lenses with fewer elements are usually fixed-focus lenses and cannot perform optical zoom. Therefore, there is currently no anti-radiation zoom lens that simultaneously offers a small number of elements, good image quality, excellent anti-radiation performance, and a high zoom ratio. Summary of the Invention

[0004] This invention provides a high-magnification, radiation-resistant zoom lens that solves the problems of excessive lens elements and low zoom ratios in current zoom lenses. While maintaining image quality, this invention uses only 8 lens elements to achieve a high-magnification, radiation-resistant zoom lens with a zoom ratio of 6x or higher, and features a simple structure, stable performance, and excellent radiation resistance.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A high-magnification anti-radiation zoom lens is characterized by comprising an object-side lens, a zoom lens group, and an image-side lens group arranged sequentially along the optical axis along the light propagation direction.

[0007] The object-side lens is fixedly disposed in the object space, the image-side lens group is fixedly disposed in the imaging focal plane, and the zoom lens group is a movable lens group.

[0008] The zoom lens group includes a first zoom lens group and a second zoom lens group. The first zoom lens group includes a second lens, a third lens, and a fourth lens arranged sequentially along the light propagation direction, and the relative positions of the second lens, the third lens, and the fourth lens remain unchanged. The second zoom lens group includes a fifth lens and a sixth lens arranged sequentially along the light propagation direction, and the relative positions of the fifth lens and the sixth lens remain unchanged. The distance between the fourth lens and the fifth lens can be moved relative to each other.

[0009] The image-side lens group includes a seventh lens and an eighth lens arranged sequentially along the light propagation direction;

[0010] An aperture stop is provided between the sixth and seventh lenses.

[0011] Furthermore, the object-side lens is a convex-concave lens, which converges the imaging beam;

[0012] The second lens is a convex-concave lens, which causes the imaging beam to diverge;

[0013] The third lens is a biconcave lens, which causes the imaging beam to diverge;

[0014] The fourth lens is a convex-concave lens that converges the imaging beam;

[0015] The fifth lens is a biconvex lens that converges the imaging beam;

[0016] The sixth lens is a concave-flat lens, which causes the imaging beam to diverge;

[0017] The seventh lens is a convex-concave lens that converges the imaging beam;

[0018] The eighth lens is a concave-convex lens that converges the imaging beam.

[0019] Furthermore, the front surface of the object-side lens has a radius of curvature of 82.0–83.1 mm, the rear surface has a radius of curvature of 213.1–216.3 mm, a thickness of 4.1–4.3 mm, a refractive index of 1.40–1.55, and an Abbe number of 65.1–68.6; the distance between the object-side lens and the front surface of the second lens is 0.2–55.6 mm.

[0020] The second lens has a front surface radius of curvature of 44.9–46.1 mm, a rear surface radius of curvature of 14.5–16.3 mm, a thickness of 3.0–3.6 mm, a refractive index of 1.40–1.55, and an Abbe number of 65.1–68.6; and a distance of 7.0–7.6 mm between it and the front surface of the third lens.

[0021] The third lens has a front surface radius of curvature of -119.9 to -116.1 mm, a rear surface radius of curvature of 27.1 to 29.3 mm, a thickness of 1.6 to 2.1 mm, a refractive index of 1.40 to 1.55, and an Abbe number of 65.1 to 68.6; and a distance of 0.3 to 0.6 mm between it and the front surface of the fourth lens.

[0022] The fourth lens has a front surface radius of curvature of 22.0–23.1 mm, a rear surface radius of curvature of 34.5–36.0 mm, a thickness of 2.0–3.3 mm, a refractive index of 1.65–1.84, and an Abbe number of 25.0–29.5; and a distance of 0.3–83.7 mm from the front surface of the fifth lens.

[0023] The fifth lens has a front surface radius of curvature of 34.7–36.9 mm, a rear surface radius of curvature of -20.1–-17.9 mm, a thickness of 4.7–5.1 mm, a refractive index of 1.40–1.55, and an Abbe number of 65.1–68.6; and a distance of 0.5–0.9 mm between it and the front surface of the sixth lens.

[0024] The sixth lens has a front surface curvature radius of -18.8 to -16.6 mm, a rear surface that is flat, a thickness of 1.5 to 2.0 mm, a refractive index of 1.65 to 1.84, and an Abbe number of 25.0 to 29.5; and a distance of 5.1 to 37.5 mm between it and the front surface of the seventh lens.

[0025] The seventh lens has a front surface radius of curvature of 16.0–17.9 mm, a rear surface radius of curvature of 39.1–41.1 mm, a thickness of 2.1–3.1 mm, a refractive index of 1.65–1.84, and an Abbe number of 25.0–29.5; and a distance of 4.9–5.3 mm from the front surface of the eighth lens.

[0026] The eighth lens has a front surface radius of curvature of -21.7 to -19.7 mm, a rear surface radius of curvature of -12.3 to -10.1 mm, a thickness of 5.0 to 5.5 mm, a refractive index of 1.59 to 1.69, and an Abbe number of 30.1 to 35.1.

[0027] Furthermore, the preferred value for the radius of curvature of the front surface of the object-side lens is 82.5 mm, the preferred value for the radius of curvature of the rear surface is 215.1 mm, the preferred value for the thickness is 4.2 mm, the preferred value for the refractive index is 1.46, and the preferred value for the Abbe number is 67.8; when it is a wide-angle lens structure, the preferred value for the distance between the object-side lens and the front surface of the second lens is 0.4 mm, and when it is a telephoto lens structure, the preferred value for the distance between the object-side lens and the front surface of the second lens is 51.4 mm.

[0028] The preferred value for the radius of curvature of the front surface of the second lens is 45.5 mm, the preferred value for the radius of curvature of the rear surface is 15.9 mm, the preferred value for the thickness is 3.3 mm, the preferred value for the refractive index is 1.46, and the preferred value for the Abbe number is 67.8; the preferred value for the distance between the second lens and the front surface of the third lens is 7.4 mm.

[0029] The preferred values ​​for the radius of curvature of the front surface of the third lens are -119.6 mm, the preferred values ​​for the radius of curvature of the rear surface are 28.3 mm, the preferred values ​​for the thickness are 2.0 mm, the preferred values ​​for the refractive index are 1.46, and the preferred values ​​for the Abbe number are 67.8; the preferred value for the distance between the third lens and the front surface of the fourth lens is 0.5 mm.

[0030] The preferred value for the radius of curvature of the front surface of the fourth lens is 23.0 mm, the preferred value for the radius of curvature of the rear surface is 35.2 mm, the preferred value for the thickness is 2.9 mm, the preferred value for the refractive index is 1.76, and the preferred value for the Abbe number is 27.5. When the lens is a wide-angle structure, the preferred value for the distance between the fourth lens and the front surface of the fifth lens is 81.4 mm, and when the lens is a telephoto structure, the preferred value for the distance between the fourth lens and the front surface of the fifth lens is 0.8 mm.

[0031] The preferred values ​​for the radius of curvature of the front surface of the fifth lens are 35.8 mm, the preferred values ​​for the radius of curvature of the rear surface are -18.9 mm, the preferred values ​​for the thickness are 5.0 mm, the preferred values ​​for the refractive index are 1.46, and the preferred values ​​for the Abbe number are 67.8; the preferred value for the distance between the fifth lens and the front surface of the sixth lens is 0.7 mm.

[0032] The preferred value for the radius of curvature of the front surface of the sixth lens is -17.6mm, the preferred value for the rear surface is a plane, the preferred value for the thickness is 1.8mm, the preferred value for the refractive index is 1.76, and the preferred value for the Abbe number is 27.5; when it is a wide-angle lens structure, the preferred value for the distance between the lens and the front surface of the seventh lens is 5.6mm, and when it is a telephoto lens structure, the preferred value for the distance between the lens and the front surface of the seventh lens is 35.2mm.

[0033] The preferred value for the radius of curvature of the front surface of the seventh lens is 16.8 mm, the preferred value for the radius of curvature of the rear surface is 40.6 mm, the thickness is 2.9 mm, the refractive index is 1.76, and the Abbe number is 27.5; the distance between the seventh lens and the front surface of the eighth lens is 5.2 mm.

[0034] The preferred values ​​for the radius of curvature of the front surface of the eighth lens are -20.1 mm, the preferred values ​​for the radius of curvature of the rear surface are -11.9 mm, the preferred values ​​for the thickness are 5.3 mm, the preferred values ​​for the refractive index are 1.65, and the preferred values ​​for the Abbe number are 33.8.

[0035] Furthermore, the object-side lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are all made of pitted radiation glass.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] This invention uses only eight lenses: an object-side lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. This enables continuous optical zoom, greatly simplifies the overall structure, reduces processing and adjustment time, and the fewer lenses there are, the better the lens's anti-radiation performance. This invention also improves the zoom ratio by adjusting the distance between the lenses, making it more convenient to use. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating the structure of the lens in this invention;

[0039] Figure 2 This is a schematic diagram of the wide-angle structure of the lens in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the telephoto structure of the lens in an embodiment of the present invention;

[0041] Figure 4 This is a wide-angle dot matrix diagram of the lens in an embodiment of the present invention;

[0042] Figure 5 This is a long focal length diagram of the lens in an embodiment of the present invention;

[0043] The accompanying figure is labeled as follows:

[0044] 1-Object-side lens, 2-Zoom lens group, 21-First zoom lens group, 211-Second lens, 212-Third lens, 213-Fourth lens, 22-Second zoom lens group, 221-Fifth lens, 222-Sixth lens, 3-Image-side lens group, 31-Seventh lens, 32-Eighth lens, 4-Aperture. Detailed Implementation

[0045] The present invention will be further described in conjunction with the accompanying drawings and specific embodiments.

[0046] A high-magnification, radiation-resistant zoom lens, such as Figure 1As shown, the system includes three lens groups: an object-side lens 1, a zoom lens group 2, and an image-side lens group 3, which are sequentially arranged along the optical axis along the light propagation direction. The object-side lens 1 is located close to the object space and has a fixed position. The object-side lens 1 is a convex-concave lens that converges the imaging beam. The zoom lens group 2 is a movable lens group, including a first zoom lens group 21 and a second zoom lens group 22. The first zoom lens group 21 includes a second lens 211, a third lens 212, and a fourth lens 213. The relative positions of the second lens 211, third lens 212, and fourth lens 213 are fixed. These three lenses can move simultaneously along the optical axis as a whole. The second lens 211 is a convex-concave lens that converges the image beam. The third lens 212 is a biconcave lens, which causes the imaging beam to diverge, while the fourth lens 213 is a convex-concave lens, which causes the imaging beam to converge. The second zoom lens group 22 includes a fifth lens 221 and a sixth lens 22. The relative positions of the fifth lens 221 and the sixth lens 222 are fixed, and the fifth lens 221 and the sixth lens 222 can move simultaneously along the optical axis as a whole. The fifth lens 221 is a biconvex lens, which causes the imaging beam to converge, while the sixth lens 222 is a concave-planar lens, which causes the imaging beam to diverge. The image-side lens group 3 is a lens group close to the imaging focal plane, and its position is fixed. It includes a seventh lens 31 and an eighth lens 32. The seventh lens 31 is a convex-concave lens, which causes the imaging beam to converge, while the eighth lens 32 is a concave-convex lens, which causes the imaging beam to converge.

[0047] A fixed aperture 4 is provided between the sixth lens 222 and the seventh lens 31.

[0048] When the lens zooms, such as Figure 2 and Figure 3 As shown, the first zoom lens group 21 and the second zoom lens group 22 move in opposite directions along the direction of light propagation: when the first zoom lens group 21 and the second zoom lens group 22 move away from each other, the lens achieves wide-angle zoom; when the first zoom lens group 21 and the second zoom lens group 22 move closer to each other, the lens achieves telephoto zoom.

[0049] The radius of curvature, lens thickness, refractive index, and Abbe number of object-side lens 1, second lens 211, third lens 212, fourth lens 213, fifth lens 221, sixth lens 22, seventh lens 31, and eighth lens 32 are specified. The three data points a / b / c in the table below correspond to the lens distances for wide-angle, intermediate focal length, and telephoto lens configurations, respectively, with the values ​​in parentheses representing the preferred values.

[0050]

[0051]

[0052] The light transmittance T of the lens after radiationz =T1*T2*·…·*T n-1 *T n It is obvious that when the radiation resistance of the glass used is comparable, the smaller the number of lenses n used in the design, the higher the light transmittance of the lens after the same total dose of radiation. When the illuminance in the object space and the back-end camera system are the same, the image formed will be clearer.

[0053] For example, a lens has 15 elements in its lens group. For ease of calculation, let's assume that the light transmittance after radiation of all the elements used is T = 0.89. Then its light transmittance after radiation is T. Z =T 15 =0.17, while the transmittance T after radiation when using the present invention Z =T8=0.39, which is 2.26 times that of a 15-element lens, and this is of great significance to image quality.

[0054] Depend on Figure 4 and Figure 5 As can be seen, the spot radius in the dot matrix diagram meets the imaging requirements and has good imaging quality.

Claims

1. A high-magnification, anti-radiation zoom lens, characterized in that, It includes an object-side lens (1), a zoom lens group (2), and an image-side lens group (3) arranged sequentially along the optical axis along the direction of light propagation. The object-side lens (1) is fixedly disposed in the object space, the image-side lens group (3) is fixedly disposed in the imaging focal plane, and the zoom lens group (2) is a movable lens group; The zoom lens group (2) includes a first zoom lens group (21) and a second zoom lens group (22). The first zoom lens group (21) includes a second lens (211), a third lens (212), and a fourth lens (213) arranged sequentially along the light propagation direction. The relative positions of the second lens (211), the third lens (212), and the fourth lens (213) remain unchanged. The second zoom lens group (22) includes a fifth lens (221) and a sixth lens (222) arranged sequentially along the light propagation direction. The relative positions of the fifth lens (221) and the sixth lens (222) remain unchanged. The distance between the fourth lens (213) and the fifth lens (221) can be moved relative to each other. The image-side lens group (3) includes a seventh lens (31) and an eighth lens (32) arranged sequentially along the light propagation direction. An aperture is provided between the sixth lens (222) and the seventh lens (31); The object-side lens (1) is a convex-concave lens that converges the imaging beam; the front surface of the object-side lens (1) has a radius of curvature of 82.0–83.1 mm, the rear surface has a radius of curvature of 213.1–216.3 mm, a thickness of 4.1–4.3 mm, a refractive index of 1.40–1.55, and an Abbe number of 65.1–68.6; the distance between the object-side lens (1) and the front surface of the second lens (211) is 0.2–55.6 mm; The second lens (211) is a convex-concave lens that causes the imaging beam to diverge; the radius of curvature of the front surface of the second lens (211) is 44.9–46.1 mm, the radius of curvature of the rear surface is 14.5–16.3 mm, the thickness is 3.0–3.6 mm, the refractive index is 1.40–1.55, and the Abbe number is 65.1–68.6; the distance between the second lens (211) and the front surface of the third lens (212) is 7.0–7.6 mm. The third lens (212) is a biconcave lens, which causes the imaging beam to diverge; the radius of curvature of the front surface of the third lens (212) is -119.9 to -116.1 mm, the radius of curvature of the rear surface is 27.1 to 29.3 mm, the thickness is 1.6 to 2.1 mm, the refractive index is 1.40 to 1.55, and the Abbe number is 65.1 to 68.6; the distance between the third lens (212) and the front surface of the fourth lens (213) is 0.3 to 0.6 mm; The fourth lens (213) is a convex-concave lens that converges the imaging beam; the radius of curvature of the front surface of the fourth lens (213) is 22.0-23.1 mm, the radius of curvature of the rear surface is 34.5-36.0 mm, the thickness is 2.0-3.3 mm, the refractive index is 1.65-1.84, and the Abbe number is 25.0-29.5; the distance between the fourth lens (213) and the front surface of the fifth lens (221) is 0.3-83.7 mm. The fifth lens (221) is a biconvex lens that converges the imaging beam; the radius of curvature of the front surface of the fifth lens (221) is 34.7 to 36.9, the radius of curvature of the rear surface is -20.1 to -17.9 mm, the thickness is 4.7 to 5.1 mm, the refractive index is 1.40 to 1.55, and the Abbe number is 65.1 to 68.6; the distance between the fifth lens (221) and the front surface of the sixth lens (222) is 0.5 to 0.9 mm; The sixth lens (222) is a concave-planar lens, which causes the imaging beam to diverge; the radius of curvature of the front surface of the sixth lens (222) is -18.8 to -16.6 mm, the rear surface is flat, the thickness is 1.5 to 2.0 mm, the refractive index is 1.65 to 1.84, and the Abbe number is 25.0 to 29.5; the distance between the sixth lens (222) and the front surface of the seventh lens (31) is 5.1 to 37.5 mm; The seventh lens (31) is a convex-concave lens that converges the imaging beam; the radius of curvature of the front surface of the seventh lens (31) is 16.0-17.9 mm, the radius of curvature of the rear surface is 39.1-41.1 mm, the thickness is 2.1-3.1 mm, the refractive index is 1.65-1.84, and the Abbe number is 25.0-29.5; the distance between the seventh lens (31) and the front surface of the eighth lens (32) is 4.9-5.3 mm; The eighth lens (32) is a concave-convex lens that converges the imaging beam; the radius of curvature of the front surface of the eighth lens (32) is -21.7 to -19.7 mm, the radius of curvature of the rear surface is -12.3 to -10.1 mm, the thickness is 5.0 to 5.5 mm, the refractive index is 1.59 to 1.69, and the Abbe number is 30.1 to 35.

1.

2. The high-magnification anti-radiation zoom lens according to claim 1, characterized in that: The object-side lens (1) has a front surface radius of curvature of 82.5 mm, a rear surface radius of curvature of 215.1 mm, a thickness of 4.2 mm, a refractive index of 1.46, and an Abbe number of 67.

8. When it is a wide-angle lens structure, the distance between it and the front surface of the second lens (211) is 0.4 mm. When the lens is a telephoto lens structure, the distance between it and the front surface of the second lens (211) is 51.4 mm. The second lens (211) has a front surface radius of curvature of 45.5 mm, a rear surface radius of curvature of 15.9 mm, a thickness of 3.3 mm, a refractive index of 1.46, and an Abbe number of 67.8; the distance between the second lens (211) and the front surface of the third lens (212) is 7.4 mm. The third lens (212) has a front surface radius of curvature of -119.6 mm, a rear surface radius of curvature of 28.3 mm, a thickness of 2.0 mm, a refractive index of 1.46, and an Abbe number of 67.8; and a distance of 0.5 mm between it and the front surface of the fourth lens (213). The fourth lens (213) has a front surface radius of curvature of 23.0 mm, a rear surface radius of curvature of 35.2 mm, a thickness of 2.9 mm, a refractive index of 1.76, and an Abbe number of 27.

5. When it is a wide-angle lens, the distance between it and the front surface of the fifth lens (221) is 81.4 mm. When it is a telephoto lens, the distance between it and the front surface of the fifth lens (221) is 0.8 mm. The fifth lens (221) has a front surface curvature radius of 35.8 mm, a rear surface curvature radius of -18.9 mm, a thickness of 5.0 mm, a refractive index of 1.46, and an Abbe number of 67.8; the distance between it and the front surface of the sixth lens (222) is 0.7 mm. The sixth lens (222) has a front surface curvature radius of -17.6 mm, a rear surface that is flat, a thickness of 1.8 mm, a refractive index of 1.76, and an Abbe number of 27.

5. When it is a wide-angle lens, the distance between it and the front surface of the seventh lens (31) is 5.6 mm. When it is a telephoto lens, the distance between it and the front surface of the seventh lens (31) is 35.2 mm. The seventh lens (31) has a front surface curvature radius of 16.8 mm, a rear surface curvature radius of 40.6 mm, a thickness of 2.9 mm, a refractive index of 1.76, and an Abbe number of 27.5; and a distance of 5.2 mm between it and the front surface of the eighth lens (32). The eighth lens (32) has a front surface curvature radius of -20.1 mm, a rear surface curvature radius of -11.9 mm, a thickness of 5.3 mm, a refractive index of 1.65, and an Abbe number of 33.

8.

3. The high-magnification anti-radiation zoom lens according to claim 2, characterized in that: The object-side lens (1), second lens (211), third lens (212), fourth lens (213), fifth lens (221), sixth lens (222), seventh lens (31), and eighth lens (32) are all made of radiation-resistant glass.

Images