Dispersion lens

Abstract

The utility model relates to the technical field of point spectrum confocal measurement, in particular to a dispersion lens, which comprises a first lens group and a second lens group which are sequentially arranged from a laser end to an object plane, a diaphragm is arranged between the first lens group and the second lens group; the focal length of the first lens group is F1; the focal length of the second lens group is F2; the first lens group comprises a first lens, a second lens and a third lens which are sequentially arranged; the first lens is a negative lens; the second lens and the third lens are positive lenses; the second lens group comprises a first doublet lens and a second doublet lens which are arranged in sequence; the focal length of the second doublet lens is F22; the air interval between the first doublet lens and the second doublet lens is d21; the outer diameter of the second doublet lens is D22; the following relational expression is satisfied: 1lt; f2 / F1lt; 1.6); 0.65 lt, 0.65 lt; f22 / F2lt; 1.05); d < 21 > / D < 22 > gt; 2. The device is large in measurement range.

Description

TECHNICAL FIELD

[0001] The utility model relates to point spectrum confocal measurement technical field, specifically related to a dispersion lens. BACKGROUND

[0002] In today's advanced industrial manufacturing and precision detection field, the current use of point spectrum confocal measurement technology has shown a very wide trend. The dispersion lens can decompose the complex light of wide spectrum into monochromatic light of different wavelengths, so that each wavelength corresponds to a specific distance value to the measured object, which is the basis of point spectrum confocal measurement technology. The optical parameters of the designed dispersion lens are crucial to the measurement range of the dispersion lens. SUMMARY

[0003] The utility model discloses a dispersion lens which overcomes the above-mentioned shortcomings.

[0004] To achieve the above object, the specific scheme of the utility model is as follows: a dispersion lens, comprising a first lens group and a second lens group arranged in sequence from a laser end to an object surface; an aperture is arranged between the first lens group and the second lens group; the focal length of the first lens group is F1; the focal length of the second lens group is F2; the first lens group comprises a first lens, a second lens and a third lens arranged in sequence; the first lens is a negative lens; the second lens and the third lens are both positive lenses; the second lens group comprises a first double cemented lens and a second double cemented lens arranged in sequence; the focal length of the second double cemented lens is F22; the air interval between the first double cemented lens and the second double cemented lens is d21; the outer diameter of the second double cemented lens is D22; the following relationships are satisfied: 1 < F2 / F1 < 1.6; 0.65 < F22 / F2 < 1.05; d21 / D22 > 2.

[0005] Further, the first lens is a double-concave lens; the second lens is a concave-convex lens; and the third lens is a symmetric double-convex lens.

[0006] Further, the curvature radius of the object side of the first lens is R1, and the curvature radius of the image side of the first lens is R2; the curvature radius of the object side of the second lens is R3, and the curvature radius of the image side of the second lens is R4; the curvature radius of the object side of the third lens is R5, and the curvature radius of the image side of the third lens is R6; wherein,

[0007] R1 ranges from -121.68 mm to -148.71 mm;

[0008] R2 ranges from 34.91 mm to 42.67 mm;

[0009] R3 is in the range of -123.96mm to -151.5107mm;

[0010] R4 is in the range of -38.50mm to -47.06mm;

[0011] R5 is in the range of 188.01mm to 229.79mm;

[0012] R6 is in the range of -188.01mm to -229.79mm.

[0013] Further, the interval between the object plane of the laser end and the object side of the first lens is in the range of 43.85mm to 53.60mm; the interval between the image side of the first lens and the object side of the second lens is in the range of 27.46mm to 33.57mm; the interval between the image side of the second lens and the object side of the third lens is in the range of 0.91mm to 1.12mm; the interval between the image side of the third lens and the diaphragm is in the range of 4.46mm to 5.46mm.

[0014] Further, the thickness of the first lens is in the range of 1.8mm to 2.2mm; the thickness of the second lens is in the range of 5.814mm to 7.106mm; the thickness of the third lens is in the range of 4.5mm to 5.5mm.

[0015] The refractive index of the first lens is in the range of 1.811 to 1.884, and the Abbe number is in the range of 22.839 to 24.742; the refractive index of the second lens is in the range of 1.634 to 1.701, and the Abbe number is in the range of 31.738 to 34.383; the refractive index of the third lens is in the range of 1.811 to 1.884, and the Abbe number is in the range of 22.838 to 24.742.

[0016] Further, the first double cemented lens is cemented by a fourth lens and a fifth lens; the fourth lens is a double convex lens; the fifth lens is a double concave lens; the second double cemented lens is cemented by a sixth lens and a seventh lens; the sixth lens is a double convex lens; the seventh lens is a concave-convex lens.

[0017] Further, the curvature radius of the object side of the fourth lens is R7, the curvature radius of the cemented surface of the fourth lens and the fifth lens is R8; the curvature radius of the image side of the fifth lens is R9; the curvature radius of the object side of the sixth lens is R10, the curvature radius of the cemented surface of the sixth lens and the seventh lens is R11; the curvature radius of the image side of the seventh lens is R12; the following relationships are satisfied:

[0018] R7 is in the range of 26.58mm to 32.50mm;

[0019] R8 is in the range of -117.85mm to -144.04mm;

[0020] R9 is in the range of 26.60mm to 32.51mm;

[0021] R10 is in the range of 113.40mm to 138.60mm;

[0022] R11 is in the range of -25.20mm to -30.80mm;

[0023] R11 is in the range of -42.30mm to -51.70mm.

[0024] Further, the interval of the diaphragm to the object side of the first double cemented lens is in the range of 0.18mm to 0.22mm; the interval of the image side of the first double cemented lens to the object side of the second double cemented lens is in the range of 89.73mm to 109.69mm; the interval of the image side of the second double cemented lens to the object plane is in the range of 84.59mm to 103.39mm.

[0025] Further, the thickness of the fourth lens is in the range of 10.125mm to 12.375mm; the thickness of the fifth lens is in the range of 2.286mm to 2.794mm; the thickness of the sixth lens is in the range of 5.940mm to 7.260mm; the thickness of the seventh lens is in the range of 1.350mm to 1.650mm.

[0026] The refractive index of the fourth lens is in the range of 1.607 to 1.672, and the Abbe number is in the range of 53.251 to 57.689; the refractive index of the fifth lens is in the range of 1.753 to 1.824, and the Abbe number is in the range of 45.620 to 49.421; the refractive index of the sixth lens is in the range of 1.467 to 1.527, and the Abbe number is in the range of 78.326 to 84.854; the refractive index of the seventh lens is in the range of 1.797 to 1.871, and the Abbe number is in the range of 35.740 to 38.720.

[0027] The beneficial effects of the utility model are as follows: two double cemented lenses are used, then 1<F2 / F1<1.6; 0.65<F22 / F2<1.05; d21 / D22>2 are met, the range of the system can be greatly improved, and the dispersion range can be greater than 6mm. BRIEF DESCRIPTION OF DRAWINGS

[0028] The utility model is further illustrated by the drawings, but the embodiments in the drawings do not constitute any limitation to the utility model, and other drawings can be obtained by the following drawings without creative labor for ordinary skilled in the art.

[0029] Figure 1 This is the optical path diagram of Embodiment 1 of this utility model;

[0030] Figure 2 This is a diagram of spherical aberration data from the imaging optics simulation of this invention;

[0031] Figure 3 This is the optical path diagram of Embodiment 2 of this utility model;

[0032] Figure 4 This is the optical path diagram of Embodiment 3 of this utility model.

[0033] Among them: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Aperture stop; 21. First cemented doublet lens; 22. Second cemented doublet lens; 30. Beam splitter; 31. Reflector. Detailed Implementation

[0034] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention. It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0035] Example 1:

[0036] like Figures 1-2As shown, a dispersive lens of this embodiment includes a first lens group and a second lens group arranged sequentially from the laser end to the object plane; an aperture stop 8 is provided between the first lens group and the second lens group; the focal length of the first lens group is F1; the focal length of the second lens group is F2; ​​the first lens group includes a first lens 1, a second lens 2, and a third lens 3 arranged sequentially; the first lens 1 is a negative lens; the second lens 2 and the third lens 3 are both positive lenses; the second lens group includes a first cemented doublet 21 and a second cemented doublet 22 arranged sequentially; the focal length of the second cemented doublet 22 is F22; the air gap between the first cemented doublet 21 and the second cemented doublet 22 is d21; the outer diameter of the second cemented doublet 22 is D22; satisfying the following relationship: 1 <F2 / F1<1.6;0.65<F22 / F2<1.05;d21 / D22> 2.

[0037] In this embodiment, the first lens 1 is a biconcave lens; the second lens 2 is a concave-convex lens; and the third lens 3 is a symmetrical biconvex lens.

[0038] In this embodiment, the radius of curvature of the object-side surface of the first lens 1 is R1, and the radius of curvature of the image-side surface of the first lens 1 is R2; the radius of curvature of the object-side surface of the second lens 2 is R3, and the radius of curvature of the image-side surface of the second lens 2 is R4; the radius of curvature of the object-side surface of the third lens 3 is R5, and the radius of curvature of the image-side surface of the third lens 3 is R6; wherein, the range of R1 is -121.68mm to -148.71mm;

[0039] The range of R2 is 34.91mm to 42.67mm;

[0040] The range of R3 is -123.96mm to -151.5107mm;

[0041] The R4 range is -38.50mm to -47.06mm;

[0042] The range of R5 is 188.01mm to 229.79mm;

[0043] The R6 range is -188.01mm to -229.79mm.

[0044] In this embodiment, the distance between the object plane of the laser end and the object side surface of the first lens 1 is 43.85mm to 53.60mm; the distance between the image side surface of the first lens 1 and the object side surface of the second lens 2 is 27.46mm to 33.57mm; the distance between the image side surface of the second lens 2 and the object side surface of the third lens 3 is 0.91mm to 1.12mm; and the distance between the image side surface of the third lens 3 and the aperture stop 8 is 4.46mm to 5.46mm.

[0045] In this embodiment, the thickness of the first lens 1 ranges from 1.8 mm to 2.2 mm; the thickness of the second lens 2 ranges from 5.814 mm to 7.106 mm; and the thickness of the third lens 3 ranges from 4.5 mm to 5.5 mm.

[0046] The first lens 1 has a refractive index range of 1.811 to 1.884 and an Abbe number range of 22.839 to 24.742; the second lens 2 has a refractive index range of 1.634 to 1.701 and an Abbe number range of 31.738 to 34.383; the third lens 3 has a refractive index range of 1.811 to 1.884 and an Abbe number range of 22.838 to 24.742.

[0047] In this embodiment, the first cemented doublet lens 21 is formed by cementing a fourth lens 4 and a fifth lens 5 together; the fourth lens 4 is a biconvex lens; the fifth lens 5 is a biconcave lens; the second cemented doublet lens 22 is formed by cementing a sixth lens 6 and a seventh lens 7 together; the sixth lens 6 is a biconvex lens; the seventh lens 7 is a concave-convex lens.

[0048] In this embodiment, the radius of curvature of the object-side surface of the fourth lens 4 is R7, and the radius of curvature of the cemented surface of the fourth lens 4 and the fifth lens 5 is R8; the radius of curvature of the image-side surface of the fifth lens 5 is R9; the radius of curvature of the object-side surface of the sixth lens 6 is R10, and the radius of curvature of the cemented surface of the sixth lens 6 and the seventh lens 7 is R11; the radius of curvature of the image-side surface of the seventh lens 7 is R12; satisfying the following relationship:

[0049] The R7 range is 26.58mm to 32.50mm;

[0050] The R8 range is -117.85mm to -144.04mm;

[0051] The R9 range is 26.60mm to 32.51mm;

[0052] The range of R10 is 113.40 mm to 138.60 mm;

[0053] The R11 range is -25.20mm to -30.80mm;

[0054] The R11 range is -42.30mm to -51.70mm.

[0055] In this embodiment, the distance between the aperture stop 8 and the object-side surface of the first cemented doublet lens 21 is 0.18 mm to 0.22 mm; the distance between the image-side surface of the first cemented doublet lens 21 and the object-side surface of the second cemented doublet lens 22 is 89.73 mm to 109.69 mm; and the distance between the image-side surface of the second cemented doublet lens 22 and the object-side surface is 84.59 mm to 103.39 mm.

[0056] In this embodiment, the thickness of the fourth lens 4 ranges from 10.125mm to 12.375mm; the thickness of the fifth lens 5 ranges from 2.286mm to 2.794mm; the thickness of the sixth lens 6 ranges from 5.940mm to 7.260mm; and the thickness of the seventh lens 7 ranges from 1.350mm to 1.650mm.

[0057] The fourth lens 4 has a refractive index range of 1.607–1.672 and an Abbe number range of 53.251–57.689; the fifth lens 5 has a refractive index range of 1.753–1.824 and an Abbe number range of 45.620–49.421; the sixth lens 6 has a refractive index range of 1.467–1.527 and an Abbe number range of 78.326–84.854; and the seventh lens 7 has a refractive index range of 1.797–1.871 and an Abbe number range of 35.740–38.720.

[0058] Specifically, after light exits the optical fiber, it first passes through the first lens 1 to expand the beam, then passes through the second lens 2 and the third lens 3 to complete the collimation process, then passes through the aperture 8, and then undergoes the fine refraction and dispersion compensation of the first cemented doublet 21 and the second cemented doublet 22 in sequence. Ultimately, this achieves the effect of precisely focusing light of different wavelengths onto different object surfaces, thereby meeting specific optical imaging or transmission requirements and ensuring that the entire optical system can operate efficiently and stably, providing a high-quality beam foundation for subsequent optical processing or detection. Figure 2 Practical application shows that the measurement range of the intrinsic chromatic aberration lens is greater than 6mm.

[0059] Furthermore, in the field of optical measurement technology, dispersive lenses and zoom lenses are quite common, and they usually function as independent measurement components. However, this traditional arrangement has certain drawbacks. In a two-dimensional measurement system, the dispersive lens and the zoom lens of the image measurement system cannot achieve coaxial measurement. Therefore, in practice, when measuring the same target, it is necessary to move the measurement platform and perform the measurement process separately using the image measurement system and the spectral confocal sensor. This approach not only significantly reduces the efficiency of the entire measurement process, but also inevitably leads to a decrease in measurement accuracy due to platform movement and the cumulative error from multiple measurements. This negatively impacts the accuracy and reliability of the measurement results, making it difficult to meet the actual needs and standards of high-precision measurement work.

[0060] This dispersive lens can also be further improved by adding a beam splitter 30, allowing the dispersive lens and the beam splitter to be coaxially positioned: the optical path at the rear end of the objective lens in the dispersive lens is a near-parallel optical path, and the front end of the dispersive lens shares an objective lens with the zoom lens objective lens, namely the second cemented doublet 22 in the dispersive lens. The beam splitter 30 deflects part of the light to the side of the zoom lens, while simultaneously allowing it to enter the rear optical path of the dispersive lens. Specifically, the beam splitter 30 can be a beam splitter plate or a beam splitter prism, and its splitting ratio can be selected according to the actual application requirements.

[0061] Since the distance between the first cemented doublet 21 and the second cemented doublet 22 of the chromatic aberration lens can reach 89.73mm to 109.69mm, there is enough space to deflect the optical path; in addition, in actual setup, the working distance of the chromatic aberration lens is at the same position as the working distance of the zoom lens.

[0062] Example 2

[0063] like Figure 3 As shown, in this embodiment, a beam splitter 30 is added, so that the dispersive lens can be mounted on the side of the imaging lens.

[0064] Example 3

[0065] like Figure 4 As shown, in this embodiment, a beam splitter 30 and a reflector 31 are added, so that the dispersive lens and the imaging lens are arranged side by side.

[0066] The above description is only a preferred embodiment of the present utility model. Therefore, any equivalent changes or modifications made to the structure, features and principles described in the claims of the present utility model patent application are included within the protection scope of the present utility model patent application.

Claims

1. A dispersive lens, characterized in that: It includes a first lens group and a second lens group arranged sequentially from the laser end to the object surface; an aperture stop (8) is provided between the first lens group and the second lens group; the focal length of the first lens group is F1; The focal length of the second lens group is F2; The first lens group includes a first lens (1), a second lens (2), and a third lens (3) arranged in sequence; the first lens (1) is a negative lens; the second lens (2) and the third lens (3) are both positive lenses; the second lens group includes a first cemented doublet lens (21) and a second cemented doublet lens (22) arranged in sequence; The focal length of the second cemented doublet (22) is F22; the air gap between the first cemented doublet (21) and the second cemented doublet (22) is d21; the outer diameter of the second cemented doublet (22) is D22; and the following relationship is satisfied: 1 <F2 / F1<1.6; 0.65 <F22 / F2<1.05; d21 / D22>2.

2. The dispersive lens according to claim 1, characterized in that: The first lens (1) is a biconcave lens; the second lens (2) is a concave-convex lens; and the third lens (3) is a symmetrical biconvex lens.

3. A dispersive lens according to claim 2, characterized in that: The object-side surface radius of curvature of the first lens (1) is R1, and the image-side surface radius of curvature of the first lens (1) is R2; the object-side surface radius of curvature of the second lens (2) is R3, and the image-side surface radius of curvature of the second lens (2) is R4; the object-side surface radius of curvature of the third lens (3) is R5, and the image-side surface radius of curvature of the third lens (3) is R6; wherein, The range of R1 is -121.68mm to -148.71mm; The range of R2 is 34.91mm to 42.67mm; The range of R3 is -123.96mm to -151.5107mm; The R4 range is -38.50mm to -47.06mm; The range of R5 is 188.01mm to 229.79mm; The R6 range is -188.01mm to -229.79mm.

4. A dispersive lens according to claim 2, characterized in that: The distance between the object plane of the laser end and the object side surface of the first lens (1) is 43.85mm to 53.60mm. The distance between the image side of the first lens (1) and the object side of the second lens (2) is 27.46 mm to 33.57 mm. The distance between the image side of the second lens (2) and the object side of the third lens (3) is 0.91 mm to 1.12 mm. The distance between the image side of the third lens (3) and the aperture (8) is 4.46 mm to 5.46 mm.

5. A dispersive lens according to claim 2, characterized in that: The thickness of the first lens (1) ranges from 1.8 mm to 2.2 mm; The thickness of the second lens (2) ranges from 5.814 mm to 7.106 mm; The thickness of the third lens (3) ranges from 4.5 mm to 5.5 mm; The refractive index of the first lens (1) ranges from 1.811 to 1.884, and its Abbe number ranges from 22.839 to 24.

742. The refractive index of the second lens (2) ranges from 1.634 to 1.701, and its Abbe number ranges from 31.738 to 34.

383. The refractive index of the third lens (3) ranges from 1.811 to 1.884, and its Abbe number ranges from 22.838 to 24.

742.

6. A dispersive lens according to claim 1, characterized in that: The first cemented doublet lens (21) is cemented together with a fourth lens (4) and a fifth lens (5); the fourth lens (4) is a biconvex lens; the fifth lens (5) is a biconcave lens; The second cemented doublet lens (22) is cemented together with a sixth lens (6) and a seventh lens (7); the sixth lens (6) is a biconvex lens; and the seventh lens (7) is a concave-convex lens.

7. A dispersive lens according to claim 6, characterized in that: The radius of curvature of the object side of the fourth lens (4) is R7, the radius of curvature of the cemented surface of the fourth lens (4) and the fifth lens (5) is R8, and the radius of curvature of the image side of the fifth lens (5) is R9. The radius of curvature of the object side surface of the sixth lens (6) is R10, and the radius of curvature of the cemented surface of the sixth lens (6) and the seventh lens (7) is R11; the radius of curvature of the image side surface of the seventh lens (7) is R12; satisfying the following relationship: The R7 range is 26.58mm to 32.50mm; The R8 range is -117.85mm to -144.04mm; The R9 range is 26.60mm to 32.51mm; The range of R10 is 113.40 mm to 138.60 mm; The R11 range is -25.20mm to -30.80mm; The R11 range is -42.30mm to -51.70mm.

8. A dispersive lens according to claim 1, characterized in that: The distance between the aperture (8) and the object side of the first cemented doublet lens (21) is 0.18 mm to 0.22 mm. The distance between the image side of the first cemented doublet (21) and the object side of the second cemented doublet (22) is 89.73 mm to 109.69 mm. The distance between the image side and the object side of the second cemented doublet lens (22) is 84.59 mm to 103.39 mm.

9. A dispersive lens according to claim 6, characterized in that: The thickness of the fourth lens (4) ranges from 10.125 mm to 12.375 mm; The thickness of the fifth lens (5) ranges from 2.286 mm to 2.794 mm; The thickness of the sixth lens (6) ranges from 5.940 mm to 7.260 mm; The thickness of the seventh lens (7) ranges from 1.350 mm to 1.650 mm; The refractive index of the fourth lens (4) ranges from 1.607 to 1.672, and its Abbe number ranges from 53.251 to 57.

689. The refractive index of the fifth lens (5) ranges from 1.753 to 1.824, and its Abbe number ranges from 45.620 to 49.

421. The refractive index of the sixth lens (6) ranges from 1.467 to 1.527, and its Abbe number ranges from 78.326 to 84.

854. The refractive index of the seventh lens (7) ranges from 1.797 to 1.871, and its Abbe number ranges from 35.740 to 38.720.

Images