Dispersion lens

Abstract

This application discloses a dispersive lens, comprising: a first lens group, a light-shielding member, and a second lens group. The first lens group directs incident light to the light-shielding member, which includes a light-shielding portion and a light-transmitting portion. The light-shielding portion blocks the central ray of the incident light, while the peripheral rays of the incident light exit through the light-transmitting portion to the second lens group. The second lens group converges the peripheral rays to form a measurement spot corresponding to each wavelength of the peripheral rays. This invention solves the technical problem of improving the accuracy of measuring objects with minute thicknesses without changing the measurement range.

Description

Technical Field

[0001] This application relates to the field of optical technology. More specifically, this application relates to a dispersive lens. Background Technology

[0002] Dispersion lenses are special lenses used in spectral confocal sensors. They are the core components of spectral confocal sensors, determining parameters such as resolution, measurement range, and linear length. Currently, the design challenge of dispersion lenses lies in the fact that most traditional dispersion lenses are large numerical aperture lenses, which are affected by spherical aberration. This causes multiple measurement spots (i.e., focal points) to appear along the depth direction for each wavelength of light at different numerical aperture angles. Figure 1 As shown, Figure 1 These are the optical path diagrams for light rays with wavelengths of 460nm and 470nm. Figure 1 The 460nm light produces two measurement spots, A1 and A2, while the 470nm light produces two measurement spots, B1 and B2. B1 is located between A1 and A2 (meaning there is an overlap between measurement spots of different wavelengths), resulting in the peak values ​​measured by the two wavelengths being as follows: Figure 2 As shown, the two peaks overlap. Therefore, when measuring objects of minute thickness, image mixing regions will appear, making it impossible for the spectral confocal sensor to measure objects of minute thickness.

[0003] To address the aforementioned shortcomings, existing technologies have employed special objectives to improve the signal-to-noise ratio without reducing the measurement range, thereby enabling the second peak to be displayed. However, the two peaks generated by this method still exhibit a high degree of overlap, failing to achieve the goal of measuring minute thicknesses. Summary of the Invention

[0004] One objective of this application is to solve the aforementioned problems and provide corresponding beneficial effects.

[0005] Another objective of this application is to provide a dispersive lens that solves the technical problem of improving the accuracy of measuring objects with minute thicknesses without changing the measurement range. This application mainly achieves this through the following technical solution:

[0006] This application provides a dispersive lens, comprising:

[0007] The first lens group, the light-shielding member, and the second lens group are provided. The first lens group is used to direct incident light to the light-shielding member. The light-shielding member includes a light-shielding part and a light-transmitting part. The light-shielding part is used to block the central ray of the incident light. The edge rays of the incident light are directed to the second lens group through the light-transmitting part. The second lens group converges the edge rays to form a measurement spot corresponding to each wavelength of the edge rays.

[0008] The beneficial effects of this application include:

[0009] This application incorporates a light-shielding component, including a light-blocking part and a light-transmitting part, within a dispersive lens. This allows the central ray of the incident light to be blocked or intercepted by the light-shielding part, while the peripheral rays (i.e., rays other than the central ray) can pass through the light-transmitting part and enter a second lens group. The second lens group then converges these rays to form measurement spots corresponding one-to-one with each wavelength of the peripheral rays. In other words, each wavelength of the incident light, after being converged by the dispersive lens provided in this application, is focused into only one measurement spot, and adjacent measurement spots are spaced a certain distance apart. Compared to existing technologies where each wavelength generates multiple measurement spots with other wavelengths existing between adjacent spots, this application avoids image mixing regions when measuring objects of minute thickness. This effectively prevents the overlap between multiple measurement spots of different wavelengths, thus avoiding the overlap of peak values ​​measured by two wavelengths. Therefore, this application can improve the accuracy of measuring objects of minute thickness without changing the measurement range.

[0010] Because there is a certain distance between two adjacent measurement spots in the multiple measurement spots converged in this application, the image formed by the dispersive lens of this application has a higher resolution and clearer imaging than the image formed by a traditional dispersive lens. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A light path diagram for converging light rays in a traditional dispersive lens;

[0013] Figure 2 A schematic diagram showing the peak value of light emitted through a conventional dispersive lens measured by a conventional spectral confocal sensor.

[0014] Figure 3 This is a schematic diagram illustrating the working principle of a spectral confocal sensor.

[0015] Figure 4 This is a schematic diagram of the optical path structure of the dispersive lens of this application in some embodiments;

[0016] Figure 5 This is the optical path diagram of the light converged by the dispersive lens of this application;

[0017] Figure 6This is a schematic diagram of the structure of the light-shielding component in some embodiments of this application;

[0018] Explanation of reference numerals in the attached drawings: 1. Dispersion lens; 10. First lens group; 11. First lens; 12. Second lens; 20. Light-shielding component; 21. Light-shielding part; 22. Light-transmitting part; 30. Second lens group; 31. Third lens; 32. Fourth lens. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the specification of embodiments of this application, the terms "first" and "second," etc., are used to distinguish different objects, rather than to describe a specific order of objects. For example, "first lens group" and "second lens group" are used to distinguish different lens groups, rather than to describe a specific order of lens groups.

[0021] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0022] Explanation of the working principle of a spectral confocal sensor:

[0023] like Figure 3 As shown, the light source exits through the S-shaped aperture and undergoes spectral dispersion after being focused by the dispersive objective lens. This results in monochromatic light focal points of different wavelengths continuously distributed along the optical axis on the image plane, with each wavelength's focal point at a different distance from the object being measured. When the object is positioned within the measurement range, only light of a specific wavelength is focused on the surface. This wavelength, satisfying the confocal condition, can be reflected from the object's surface and enter the spectrometer. Other wavelengths are defocused on the object's surface and cannot enter the spectrometer after reflection. The wavelength of the maximum echo intensity is obtained by decoding the light using the spectrometer, thus determining the distance to the object.

[0024] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0025] like Figure 4The image shown is a dispersive lens 1 provided in an embodiment of this application. Figure 4 In the above, the dispersive lens 1 includes a first lens group 10, a light-shielding member 20, and a second lens group 30. The first lens group 10 directs incident light to the light-shielding member 20. The light-shielding member 20 includes a light-shielding portion 21 and a light-transmitting portion 22, such as... Figure 6 As shown, the light-shielding part 21 is used to block the central ray of the incident light, and the edge ray of the incident light is emitted through the light-transmitting part 22 to the second lens group 30. The second lens group 30 converges the edge ray to form a measurement spot corresponding to each wavelength of the edge ray.

[0026] like Figure 5 As shown, Figure 5 The image shows the optical path of light rays with wavelengths of 460nm and 470nm converged by the dispersive lens 1. The 460nm light rays converge into only one measurement spot C, and the 470nm light rays also converge into only one measurement spot D. Furthermore, the imaging regions of the two wavelengths are spaced apart, preventing overlap. Therefore, this application can improve the resolution of the image of the measured object and enhance the accuracy of measuring objects with minute thicknesses.

[0027] It should be understood that the dispersive lens 1 provided in the embodiments of this application is applied to a point spectral confocal sensor.

[0028] The size of the Airy disk radius of the edge rays does not change even if the central rays are blocked by the occluded portion.

[0029] The first lens group 10 is used to allow light at a larger angle to enter the light-shielding member 20; the second lens group 30 is used to disperse different light to different depth positions, that is, to converge light of different wavelengths.

[0030] In some embodiments, the first lens group 10 includes a first lens 11 and a second lens 12.

[0031] The incident surface radius of curvature of the first lens 11 is set to 172.64 mm, the thickness is set to 2.8 mm, the material is H-ZF88, and the semi-diameter is set to 4.11 mm.

[0032] The first lens 11 has an exit surface curvature radius of -15.66 mm, a thickness of 0.33 mm, and a semi-diameter of 4.30 mm.

[0033] The second lens 12 has an incident surface curvature radius of -12.87 mm, a thickness of 2 mm, is made of H-ZF88 material, and a semi-diameter of 4.28 mm.

[0034] The second lens 12 has an exit surface curvature radius of -19.31 mm, a thickness of 0.20 mm, and a semi-diameter of 4.54 mm.

[0035] In this embodiment, the first lens 11 is a cemented doublet lens, and the second lens 12 is a uniform lens. The cemented doublet lens and the uniform lens can effectively reduce spherical aberration, or even reduce it to zero.

[0036] In some embodiments, the light-shielding member 20 is an aperture.

[0037] In some embodiments, the light-shielding portion 21 has a black coating layer. Specifically, the black coating layer covers the entire light-shielding portion 21.

[0038] In some embodiments, the second lens group 30 includes a third lens 31 and a fourth lens 32.

[0039] The incident surface radius of curvature of the third lens 31 is set to 19.31 mm, the thickness is set to 2 mm, the material is H-ZF88, and the semi-diameter is set to 4.54 mm.

[0040] The radius of curvature of the exit surface of the third lens 31 is set to 12.87 mm, the thickness is set to 0.33 mm, and the semi-diameter is set to 4.28 mm.

[0041] The incident surface radius of curvature of the fourth lens 32 is set to 15.66 mm, the thickness is set to 2.80 mm, the material is H-ZF88, and the semi-diameter is set to 4.30 mm.

[0042] The radius of curvature of the exit surface of the fourth lens 32 is set to -172.64 mm, the thickness is set to 15.15 mm, and the semi-diameter is set to 4.11 mm.

[0043] The third lens 31 is a Qiming lens, and the fourth lens 32 is a cemented doublet lens.

[0044] In some embodiments, the dispersive lens 1 further includes a lens barrel for fixing the first lens group 10, the light-shielding member 20, and the second lens group 30.

[0045] The present application and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present application. The actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the embodiments of the present application, such designs should fall within the protection scope of the embodiments of the present application.

Claims

1. A dispersive lens, characterized in that, include: A first lens group, a light-shielding member, and a second lens group are provided. The first lens group directs incident light to the light-shielding member, which includes a light-shielding portion and a light-transmitting portion. The light-shielding portion blocks the central ray of the incident light, while the peripheral rays of the incident light exit through the light-transmitting portion to the second lens group. The second lens group converges the peripheral rays to form a measurement spot corresponding to each wavelength of the peripheral rays. The first lens group includes a first lens and a second lens; the first lens is a cemented doublet lens, and the second lens is a luminous lens; The radius of curvature of the incident surface of the first lens is set to 172.64 mm, the thickness is set to 2.8 mm, and the semi-diameter is set to 4.11 mm; the radius of curvature of the exit surface of the first lens is set to -15.66 mm, the thickness is set to 0.33 mm, and the semi-diameter is set to 4.30 mm. The radius of curvature of the incident surface of the second lens is set to -12.87 mm, the thickness is set to 2 mm, and the semi-diameter is set to 4.28 mm; the radius of curvature of the exit surface of the second lens is set to -19.31 mm, the thickness is set to 0.20 mm, and the semi-diameter is set to 4.54 mm. The second lens group includes a third lens and a fourth lens; the third lens is a luminous lens, and the fourth lens is a cemented doublet lens; The radius of curvature of the incident surface of the third lens is set to 19.31 mm, the thickness is set to 2 mm, and the semi-diameter is set to 4.54 mm; the radius of curvature of the exit surface of the third lens is set to 12.87 mm, the thickness is set to 0.33 mm, and the semi-diameter is set to 4.28 mm. The incident surface radius of curvature of the fourth lens is set to 15.66 mm, the thickness is set to 2.80 mm, and the semi-diameter is set to 4.30 mm; the exit surface radius of curvature of the fourth lens is set to -172.64 mm, the thickness is set to 15.15 mm, and the semi-diameter is set to 4.11 mm.

2. The dispersive lens according to claim 1, characterized in that, The light-shielding component is an aperture.

3. The dispersive lens according to claim 1, characterized in that, The light-shielding part has a black coating.

4. The dispersive lens according to claim 1, characterized in that, The dispersive lens also includes a lens barrel for fixing the first lens group, the light-shielding member, and the second lens group.

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