High-precision imaging lens for 3D line laser sensor

Abstract

The utility model discloses a high-precision imaging lens for a 3D line laser sensor. Comprising a zero-focal-power first lens, a positive-focal-power second lens, a positive-focal-power third lens, a positive-focal-power fourth lens, a positive-focal-power fifth lens, a diaphragm, a negative-focal-power sixth lens, a positive-focal-power seventh lens and a positive-focal-power eighth lens which are sequentially arranged along an optical axis. According to the high-precision imaging lens, the diaphragm is arranged between the fifth lens and the sixth lens, so that the angle of light entering the lens can be effectively controlled, and the aperture of the lens is reduced; according to the high-precision imaging lens, the eight lenses with specific focal power are adopted, the focal power of the eight lenses is reasonably distributed, and the surface type of the lenses is reasonably controlled, so that the optical lens still has good imaging quality under the condition that the optical lens meets the Sammer principle, and meanwhile, the optical lens has small distortion and low cost.

Description

Technical Field

[0001] The utility model relates to the technical field of optical imaging, and in particular to a high-precision imaging lens for a 3D line laser sensor. Background Art

[0002] With the rapid development of industrial automation, the demand for 3D line laser sensors is increasing. Lenses are the core component of 3D line laser sensors. The resolution of the lens often determines the resolution of the 3D line laser sensor. Existing imaging lenses cannot meet the technical requirements of 3D line laser sensors while also providing good imaging quality. Utility Model Content

[0003] The purpose of this application is to provide a high-precision imaging lens for a 3D line laser sensor to address the technical defects in the prior art.

[0004] The technical solutions adopted to achieve the purpose of this application are:

[0005] A high-precision imaging lens for a 3D line laser sensor, comprising a first lens with zero optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, an aperture, a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with positive optical power, which are sequentially arranged along an optical axis;

[0006] The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens all include an object-side surface and an image-side surface; the object-side surface of the first lens is a plane, the image-side surface of the first lens is a plane, the object-side surface of the second lens is a convex surface, the image-side surface of the second lens is a convex surface, the object-side surface of the third lens is a convex surface, the image-side surface of the third lens is a plane, the object-side surface of the fourth lens is a convex surface, the image-side surface of the fourth lens is a concave surface, the object-side surface of the fifth lens is a concave surface, the image-side surface of the fifth lens is a convex surface, the object-side surface of the sixth lens is a concave surface, the image-side surface of the sixth lens is a plane, the object-side surface of the seventh lens is a plane, the image-side surface of the seventh lens is a convex surface, the object-side surface of the eighth lens is a convex surface, and the image-side surface of the eighth lens is a convex surface.

[0007] In the above technical solution, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are made of the same material, which is glass.

[0008] In the above technical solution, the curvature radii of the object-side surface of the first lens and the image-side surface of the first lens are both infinite; the object-side surface thickness / surface spacing of the first lens is 1.0000 mm; the image-side surface thickness / surface spacing of the first lens is 0.4565 mm; the refractive index and Abbe number of the object-side surface of the first lens and the image-side surface of the first lens are the same, the refractive index is 1.5200, and the Abbe number is 64.2000.

[0009] In the above technical solution, the object side surface of the second lens has a curvature radius of 163.5699 mm, and the thickness / surface spacing is 1.4565 mm; the image side surface of the second lens has a curvature radius of -162.5468 mm, and the thickness / surface spacing is 0.8755 mm; the object side surface of the second lens and the image side surface of the second lens have the same focal length, refractive index and Abbe number, the focal length is 132.1583 mm, the refractive index is 1.6000, and the Abbe number is 60.6000.

[0010] In the above technical solution, the object side surface of the third lens has a curvature radius of 27.5468 mm, and the thickness / surface spacing is 2.4565 mm. The image side surface of the third lens has an infinite curvature radius, and the thickness / surface spacing is 0.8456 mm. The object side surface of the third lens and the image side surface of the third lens have the same focal length, refractive index and Abbe number, the focal length is 42.9699 mm, the refractive index is 1.6200, and the Abbe number is 58.1000.

[0011] In the above technical solution, the object side surface of the fourth lens has a curvature radius of 7.4584 mm, and a thickness / surface spacing of 4.3565 mm; the image side surface of the fourth lens has a curvature radius of 5.8246 mm, and a thickness / surface spacing of 2.0456 mm; the object side surface of the fourth lens and the image side surface of the fourth lens have the same focal length, refractive index and Abbe number, the focal length is -313.1087 mm, the refractive index is 1.6900, and the Abbe number is 54.5000.

[0012] In the above technical solution, the object side surface of the fifth lens has a curvature radius of -23.4565 mm, and the thickness / surface spacing is 1.9755 mm; the image side surface of the fifth lens has a curvature radius of -19.4563 mm, and the thickness / surface spacing is 1.4565 mm; the object side surface of the fifth lens and the image side surface S10 of the fifth lens have the same focal length, refractive index and Abbe number, the focal length is 96.1083 mm, the refractive index is 1.9000, and the Abbe number is 31.2000.

[0013] In the above technical solution, the object side surface radius of the sixth lens is -17.4565 mm, the thickness / surface spacing is 2.5465 mm, the image side surface radius of the sixth lens is infinite, and the thickness / surface spacing is 3.4565 mm; the object side surface of the sixth lens and the image side surface S12 of the sixth lens have the same focal length, refractive index and Abbe number, the focal length is -20.1912 mm, the refractive index is 1.8100, and the Abbe number is 25.5000.

[0014] In the above technical solution, the object-side surface of the seventh lens has an infinite radius of curvature, and the thickness / surface spacing is 5.7868 mm. The image-side surface of the seventh lens has a radius of curvature of -15.4565 mm, and the thickness / surface spacing is 4.9880 mm. The object-side surface of the seventh lens and the image-side surface of the seventh lens have the same focal length, refractive index, and Abbe number: the focal length is 29.1518 mm, the refractive index is 1.5200, and the Abbe number is 64.2000.

[0015] In the above technical solution, the object-side surface radius of the eighth lens is 82.4569 mm, and the thickness / surface spacing is 2.4565 mm. The image-side surface radius of the eighth lens is -111.4565 mm, and the thickness / surface spacing is 28.4349 mm. The object-side surface of the eighth lens and the image-side surface of the eighth lens have the same focal length, refractive index, and Abbe number: the focal length is 56.7144 mm, the refractive index is 1.8100, and the Abbe number is 41.0000.

[0016] The beneficial effects of the utility model are as follows:

[0017] 1. The high-precision imaging lens of the present invention sets the aperture between the fifth lens and the sixth lens, which can effectively control the angle of light entering the lens and reduce the aperture of the lens.

[0018] 2. The high-precision imaging lens of this utility model adopts eight lenses with specific optical focal lengths. By rationally distributing the optical focal lengths of the eight lenses and rationally controlling the surface shape of the lenses, the optical lens can still have good imaging quality while meeting the Sham principle, while having smaller distortion and lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1This is a schematic structural diagram of the high-precision imaging lens described in the present utility model.

[0021] Figure 2 This is a field curvature and distortion curve diagram of the high-precision imaging lens described in the present utility model.

[0022] Figure 3 This is a relative illumination curve diagram of the high-precision imaging lens described in the present utility model.

[0023] In the figure: 1-first lens, 2-second lens, 3-third lens, 4-fourth lens, 5-fifth lens, 6-sixth lens, 7-seventh lens, 8-eighth lens, 9-aperture, S1-object side surface of the first lens, S2-image side surface of the first lens, S3-object side surface of the second lens, S4-image side surface of the second lens, S5-object side surface of the third lens, S6-image side surface of the third lens, S7-object side surface of the fourth lens, S8-image side surface of the fourth lens, S9-object side surface of the fifth lens, S10-image side surface of the fifth lens, S11-object side surface of the sixth lens, S12-image side surface of the sixth lens, S13-object side surface of the seventh lens, S14-image side surface of the seventh lens, S15-object side surface of the eighth lens, S16-image side surface of the eighth lens. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with specific embodiments.

[0025] A high-precision imaging lens for 3D line laser sensors, see Figure 1 , including a first lens 1 with zero optical power, a second lens 2 with positive optical power, a third lens 3 with positive optical power, a fourth lens 4 with positive optical power, a fifth lens 5 with positive optical power, an aperture 9, a sixth lens 6 with negative optical power, a seventh lens 7 with positive optical power and an eighth lens 8 with positive optical power, which are arranged in sequence along the optical axis. The aperture 9 is set between the fifth lens 5 and the sixth lens 6, which can effectively control the angle of light entering the lens and reduce the aperture of the lens.

[0026] The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7 and the eighth lens 8 all include an object-side surface and an image-side surface; the object-side surface S1 of the first lens 1 is a plane, the image-side surface S2 of the first lens 1 is a plane, the object-side surface S3 of the second lens 2 is a convex surface, the image-side surface S4 of the second lens 2 is a convex surface, the object-side surface S5 of the third lens 3 is a convex surface, the image-side surface S6 of the third lens 3 is a plane, the object-side surface S7 of the fourth lens 4 is a convex surface, the image-side surface S8 of the fourth lens 4 is a concave surface, the object-side surface S9 of the fifth lens 5 is a concave surface, the image-side surface S10 of the fifth lens 5 is a convex surface, the object-side surface S11 of the sixth lens 6 is a concave surface, the image-side surface S12 of the sixth lens 6 is a plane, the object-side surface S13 of the seventh lens 7 is a plane, the image-side surface S14 of the seventh lens 7 is a convex surface, the object-side surface S15 of the eighth lens 8 is a convex surface, and the image-side surface S16 of the eighth lens 8 is a convex surface. By using eight lenses with specific optical power, rationally distributing the optical power of the eight lenses and rationally controlling the surface shape of the lenses, the optical lens can still have good imaging quality while meeting the Sham principle, while having smaller distortion and lower cost.

[0027] The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7 and the eighth lens 8 are made of the same material, which is glass. The curvature radius of the object side surface S1 of the first lens 1 and the image side surface S2 of the first lens are both infinite; the thickness / surface spacing of the object side surface S1 of the first lens 1 is 1.0000mm; the thickness / surface spacing of the image side surface S2 of the first lens is 0.4565mm; the refractive index and Abbe number of the object side surface S1 of the first lens 1 and the image side surface S2 of the first lens are the same, the refractive index is 1.5200, and the Abbe number is 64.2000; the curvature radius of the object side surface S3 of the second lens 2 is 163.5699mm, the thickness / surface spacing is 1.4565mm, and the curvature radius of the image side surface S4 of the second lens 2 is -162.5468 mm, and the thickness / surface spacing is 0.8755 mm; the object side surface S3 of the second lens 2 has the same focal length, refractive index and Abbe number as the image side surface S4 of the second lens 2, and the focal length is 132.1583 mm, the refractive index is 1.6000, and the Abbe number is 60.6000; the object side surface S5 of the third lens 3 has a curvature radius of 27.5468 mm, a thickness / surface spacing of 2.4565 mm, and the image side surface S6 of the third lens 3 has an infinite curvature radius, and a thickness / surface spacing of 0.8456 mm; the object side surface S5 of the third lens 3 has the same focal length, refractive index and Abbe number as the image side surface S6 of the third lens 3, and the focal length is The object side surface S7 of the fourth lens 4 has a curvature radius of 7.4584 mm, a thickness / surface spacing of 4.3565 mm, and an image side surface S8 of the fourth lens 4 has a curvature radius of 5.8246 mm, a thickness / surface spacing of 2.0456 mm; the object side surface S7 of the fourth lens 4 has the same focal length, refractive index and Abbe number as the image side surface S8 of the fourth lens 4, the focal length is -313.1087 mm, the refractive index is 1.6900, and the Abbe number is 54.5000; the object side surface S9 of the fifth lens 5 has a curvature radius of -23.4 The object-side surface S11 of the sixth lens 6 has a curvature radius of -17.4565 mm and a thickness / surface spacing of 2.5465 mm. The image-side surface S12 of the sixth lens 6 has an infinite curvature radius and a thickness / surface spacing of 3.4565mm; the object-side surface S11 of the sixth lens 6 and the image-side surface S12 of the sixth lens 6 have the same focal length, refractive index and Abbe number, the focal length is -20.1912mm, the refractive index is 1.8100, and the Abbe number is 25.5000; the object-side surface S13 of the seventh lens 7 has an infinite radius of curvature, a thickness / surface spacing of 5.7868mm, and the image-side surface S14 of the seventh lens 7 has a radius of curvature of -15.4565mm, and a thickness / surface spacing of 4.9880mm; the object-side surface S13 of the seventh lens 7 and the image-side surface S14 of the seventh lens 7 have the same focal length, refractive index and Abbe number, The focal length is 29.1518 mm, the refractive index is 1.5200, and the Abbe number is 64.2000. The object-side surface S15 of the eighth lens element 8 has a radius of curvature of 82.4569 mm and a thickness / surface spacing of 2.4565 mm. The image-side surface S16 of the eighth lens element 8 has a radius of curvature of -111.4565 mm and a thickness / surface spacing of 28.4349 mm. The object-side surface S15 and the image-side surface S16 of the eighth lens element 8 have the same focal length, refractive index, and Abbe number: 56.7144 mm, a refractive index of 1.8100, and an Abbe number of 41.0000. This is shown in Table 1.

[0028] Table 1 Design parameters of high-precision imaging lens

[0029]

[0030] See also Figure 2 The field curvature of the high-precision imaging lens of this utility model is within ±0.05, and the distortion is within ±0.1%; see Figure 3 From the relative illumination, it can be seen that the illumination within the field of view of the high-precision imaging lens is greater than 70%. It can be seen that the high-precision imaging lens has the characteristics of good imaging quality, small distortion, and high illumination.

[0031] An imaging method using a high-precision imaging lens based on a 3D line laser sensor, comprising the following steps:

[0032] Step 1: inject light into the first lens 1, and use the first lens 1 to filter out stray light from the incident light;

[0033] Step 2: The light that has filtered out the stray light enters the second lens 2, and the second lens 2 is used to collect the light outside the field of view and converge it into the imaging lens;

[0034] Step 3: Use the third lens 3 to expand the aperture of the imaging lens, and the converged light enters the third lens 3;

[0035] Step 4, using the fourth lens 4, the fifth lens 5 and the sixth lens 6 to correct the residual aberration of the imaging lens, the light emitted by the third lens 3 is incident on the fourth lens 4, the fifth lens 5 and the sixth lens 6 in sequence;

[0036] Step 5: The light emitted from the sixth lens 6 is incident on the seventh lens 7 and the eighth lens 8 in sequence. The seventh lens 7 and the eighth lens 8 are used to control the emission angle of the light, and finally converge to form an image.

[0037] For ease of explanation, spatial relative terms such as "upper", "lower", "left", and "right" are used in the embodiments to illustrate the relationship between one element or feature shown in the figures and another element or feature. It should be understood that, in addition to the orientation shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0038] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any actual relationship or order between these components.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high-precision imaging lens for a 3D line laser sensor, characterized in that: The lens comprises a first lens with zero optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, an aperture, a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with positive optical power, which are sequentially arranged along the optical axis. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens all include an object-side surface and an image-side surface; the object-side surface of the first lens is a plane, the image-side surface of the first lens is a plane, the object-side surface of the second lens is a convex surface, the image-side surface of the second lens is a convex surface, the object-side surface of the third lens is a convex surface, the image-side surface of the third lens is a plane, the object-side surface of the fourth lens is a convex surface, the image-side surface of the fourth lens is a concave surface, the object-side surface of the fifth lens is a concave surface, the image-side surface of the fifth lens is a convex surface, the object-side surface of the sixth lens is a concave surface, the image-side surface of the sixth lens is a plane, the object-side surface of the seventh lens is a plane, the image-side surface of the seventh lens is a convex surface, the object-side surface of the eighth lens is a convex surface, and the image-side surface of the eighth lens is a convex surface.

2. The high-precision imaging lens according to claim 1, wherein: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are made of the same material, which is glass.

3. The high-precision imaging lens according to claim 1, wherein: The curvature radii of the object side surface and the image side surface of the first lens are both infinite; the object side surface thickness / surface spacing of the first lens is 1.0000 mm; the image side surface thickness / surface spacing of the first lens is 0.4565 mm; the refractive index and Abbe number of the object side surface of the first lens and the image side surface of the first lens are the same, the refractive index is 1.5200, and the Abbe number is 64.2000.

4. The high-precision imaging lens according to claim 1, wherein: The object side surface of the second lens has a curvature radius of 163.5699 mm, and the thickness / surface spacing is 1.4565 mm. The image side surface of the second lens has a curvature radius of -162.5468 mm, and the thickness / surface spacing is 0.8755 mm. The object side surface of the second lens has the same focal length, refractive index and Abbe number as the image side surface of the second lens, the focal length is 132.1583 mm, the refractive index is 1.6000, and the Abbe number is 60.6000.

5. The high-precision imaging lens according to claim 1, wherein: The object side surface of the third lens has a curvature radius of 27.5468 mm, and the thickness / surface spacing is 2.4565 mm. The image side surface of the third lens has an infinite curvature radius, and the thickness / surface spacing is 0.8456 mm. The object side surface of the third lens and the image side surface of the third lens have the same focal length, refractive index and Abbe number, the focal length is 42.9699 mm, the refractive index is 1.6200, and the Abbe number is 58.1000.

6. The high-precision imaging lens according to claim 1, wherein: The object side surface of the fourth lens has a curvature radius of 7.4584 mm, and a thickness / surface spacing of 4.3565 mm. The image side surface of the fourth lens has a curvature radius of 5.8246 mm, and a thickness / surface spacing of 2.0456 mm. The object side surface of the fourth lens has the same focal length, refractive index and Abbe number as the image side surface of the fourth lens, the focal length is -313.1087 mm, the refractive index is 1.6900, and the Abbe number is 54.5000.

7. The high-precision imaging lens according to claim 1, wherein: The object side surface of the fifth lens has a curvature radius of -23.4565 mm, and the thickness / surface spacing is 1.9755 mm. The image side surface of the fifth lens has a curvature radius of -19.4563 mm, and the thickness / surface spacing is 1.4565 mm. The object side surface of the fifth lens and the image side surface S10 of the fifth lens have the same focal length, refractive index and Abbe number, the focal length is 96.1083 mm, the refractive index is 1.9000, and the Abbe number is 31.2000.

8. The high-precision imaging lens according to claim 1, wherein: The object side surface of the sixth lens has a curvature radius of -17.4565 mm, and the thickness / surface spacing is 2.5465 mm. The image side surface of the sixth lens has an infinite curvature radius, and the thickness / surface spacing is 3.4565 mm. The object side surface of the sixth lens and the image side surface S12 of the sixth lens have the same focal length, refractive index and Abbe number, the focal length is -20.1912 mm, the refractive index is 1.8100, and the Abbe number is 25.5000.

9. The high-precision imaging lens according to claim 1, wherein: The object side surface of the seventh lens has an infinite radius of curvature, and the thickness / surface spacing is 5.7868 mm. The image side surface of the seventh lens has a radius of curvature of -15.4565 mm, and the thickness / surface spacing is 4.9880 mm. The object side surface of the seventh lens and the image side surface of the seventh lens have the same focal length, refractive index and Abbe number, the focal length is 29.1518 mm, the refractive index is 1.5200, and the Abbe number is 64.2000.

10. The high-precision imaging lens according to claim 1, wherein: The object side surface of the eighth lens has a curvature radius of 82.4569 mm, and a thickness / surface spacing of 2.4565 mm. The image side surface of the eighth lens has a curvature radius of -111.4565 mm, and a thickness / surface spacing of 28.4349 mm. The object side surface of the eighth lens and the image side surface of the eighth lens have the same focal length, refractive index and Abbe number, namely, the focal length is 56.7144 mm, the refractive index is 1.8100, and the Abbe number is 41.0000.

Images