CN115685497A - Dispersion lens - Google Patents

Abstract

The application discloses dispersion lens includes: the light source comprises a first lens group, a light shielding component and a second lens group, wherein the first lens group is used for emitting incident light to the light shielding component, the light shielding component comprises a light shielding part and a light transmitting part, the light shielding part is used for shielding central light of the incident light, marginal light of the incident light is emitted to the second lens group through the light transmitting part, and the second lens group converges the marginal light to form measuring light spots corresponding to each wavelength in the marginal light one to one. The invention solves the technical problem of how to improve the precision of measuring a measured object with a tiny thickness under the condition of not changing the measuring range.

Description

Dispersion lens

technical field

This application relates to the field of optical technology. More specifically, the present application relates to a dispersive lens.

Background technique

Dispersion lens is a special lens applied to spectral confocal sensor. It is the core device of spectral confocal sensor, which determines the resolution, range, line length and other parameters. The difficulty in the design of the current dispersion lens is that most of the traditional dispersion lenses are lenses with large numerical apertures, which have the influence of spherical aberration, so that each wavelength of light will have multiple measurement spots in the depth direction of the lens at different numerical aperture angles (also That is, the focus point), as shown in Figure 1, Figure 1 is the light path diagram of light with wavelengths of 460nm and 470nm, in Figure 1, the 460nm light produces two measurement spots A1 and A2, and the 470nm light produces two measurement spots B1 and B2, where , B1 is located between A1 and A2 (that is, the measurement spots of different wavelengths have a cross phenomenon), resulting in the peaks measured by the two wavelengths as shown in Figure 2, that is, the two peaks overlap. In this way, when measuring a measured object with a small thickness, an image mixing area will appear in its imaging, making it impossible for the spectral confocal sensor to measure a measured object with a small thickness.

For the above defects, the existing technology uses a special objective lens to improve the signal-to-noise ratio without reducing the range, so that the second peak can be displayed, but the two peaks produced by this method still have a high degree of coincidence. Still can not reach the purpose of measuring tiny thickness.

Contents of the invention

One purpose of the present application is to solve the above problems and provide corresponding beneficial effects.

Another object of the present application is to provide a dispersive lens, which solves the technical problem of how to improve the accuracy of measuring a measured object with a small thickness without changing the measuring range. The application is mainly realized through the following technical solutions:

The application provides a dispersion lens, including:

The first lens group, the light-shielding member and the second lens group, wherein the first lens group is used to emit incident light to the light-shielding member, the light-shielding member includes a light-shielding part and a light-transmitting part, and the light-shielding part uses In order to block the central ray of the incident light, the marginal ray of the incident light is emitted to the second lens group through the light-transmitting part, and the second lens group converges the marginal ray to form a There is a one-to-one measurement spot for each wavelength.

The beneficial effects of the application include:

In the present application, a light shielding member including a light shielding part and a light transmitting part is arranged in the dispersion lens, so that the central ray of the incident light of the present application is blocked or intercepted by the light shielding part, and the marginal light rays of the incident light (that is, light rays other than the central light rays) can be Incident to the second lens group through the light-transmitting part, the second lens group converges to form a measurement spot corresponding to each wavelength of the marginal light rays. That is to say, the rays of each wavelength in the incident light are converged into only one measurement spot after being converged by the dispersion lens provided by the present application, and there is a certain distance between two adjacent measurement spots. Compared with the light of each wavelength in the prior art that produces multiple measurement spots and there are other wavelengths of light spots between two adjacent measurement spots, when the application measures the measured object with a small thickness, its imaging will not An image mixing area appears, so the phenomenon of crossing between the multiple measurement spots of different wavelengths can be effectively avoided, and then the overlapping of the peaks measured by the two wavelengths can be avoided. Therefore, the present application can improve the accuracy of measuring a measured object with a small thickness without changing the measuring range.

Due to the fact that there is a certain distance between two adjacent measurement spots among the multiple measurement spots gathered by this application, the resolution of the image formed by the dispersion lens of this application is higher than that of the image formed by the traditional dispersion lens , the image is clearer.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments of the present application. Obviously, the accompanying drawings in the following description are only some embodiments of the present application , for those skilled in the art, other drawings can also be obtained according to these drawings without paying creative labor.

Fig. 1 is the optical path diagram of the convergent light of the traditional dispersion lens;

Figure 2 is a schematic diagram of the peak value of the light emitted by the traditional dispersive lens measured by the traditional spectral confocal sensor;

Figure 3 is a schematic diagram of the working principle of the spectral confocal sensor;

Fig. 4 is a schematic diagram of the optical path structure of the dispersion lens of the present application in some embodiments;

Fig. 5 is the optical path diagram of the dispersive lens convergent light of the present application;

Fig. 6 is a schematic structural view of a light-shielding member in some embodiments of the present application;

Explanation of Reference Signs: 1. Dispersion lens; 10. First lens group; 11. First lens; 12. Second lens; 20. Light shielding member; 21. Light shielding part; group; 31, the third lens; 32, the fourth lens.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be clearly and completely described below in conjunction with the drawings in the embodiments of the application. Obviously, the described implementation The examples are some of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

The terms "first" and "second" in the description of the embodiments of the present application are used to distinguish different objects, rather than to describe a specific sequence of objects. For example, the first lens group and the second lens group are used to distinguish different lens groups, not to describe a specific order of the lens groups.

In the embodiments of the present application, words such as "exemplary" or "for example" are used as examples, illustrations or illustrations. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present application shall not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete manner.

Explanation of the working principle of the spectral confocal sensor:

As shown in Figure 3, the light source emerges from the small hole S, and after being focused by the dispersive objective lens, spectral dispersion occurs, forming a monochromatic light focus with different wavelengths continuously distributed along the optical axis direction on the image surface, and the monochromatic light of each wavelength The distance from the focal point to the measured object is different. When the measured object is at a certain position within the measurement range, only the light of a specific wavelength is focused on the measured surface, and the light of this wavelength can be reflected from the surface of the measured object and enter the spectrometer because it meets the confocal condition, while other The light of the wavelength is in a defocused state on the surface of the measured object, and cannot enter the spectrometer after reflection. The wavelength value at the maximum echo light intensity is obtained by decoding the spectrometer, so as to measure the distance value corresponding to the measured object.

The specific implementation manners of the present application will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 4 , it is the dispersion lens 1 provided by the embodiment of the present application. In FIG. 4 , the dispersion lens 1 includes a first lens group 10, a light shielding member 20 and a second lens group 30, wherein the first lens group 10 is used to emit incident light to the light shielding member 20, so The light-shielding member 20 includes a light-shielding portion 21 and a light-transmitting portion 22. As shown in FIG. The light is emitted to the second lens group 30, and the second lens group 30 converges the marginal rays to form a measurement spot corresponding to each wavelength of the marginal rays.

As shown in Figure 5, Figure 5 is an optical path diagram of light rays with a wavelength of 460nm and 470nm converged by the dispersion lens 1, the light with a wavelength of 460nm is only converged into one measurement spot C, and the light with a wavelength of 470nm is also converged into only one spot C There is a measurement spot D, and there is a certain distance between the imaging areas of the two wavelengths, and there will be no overlap. Therefore, the present application can improve the imaging resolution of the measured object, and improve the accuracy of measuring the measured object with a small thickness.

It should be understood that the dispersion lens 1 provided in the embodiment of the present application is applied to a point spectrum confocal sensor.

The size of the Airy disk radius of the marginal ray does not change due to the blocking of the central ray by the shielding part.

The first lens group 10 is used to allow all light with a larger angle to enter the light shielding member 20; the second lens group 30 is used to disperse different lights to different depth positions, that is, to converge different light wavelength of light.

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

The radius of curvature of the incident surface 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.

The radius of curvature of the exit surface of the first lens 11 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 12 is set to -12.87mm, the thickness is set to 2mm, the material is H-ZF88, and the semi-diameter is set to 4.28mm.

The radius of curvature of the exit surface of the second lens 12 is set to -19.31 mm, the thickness is set to 0.20 mm, and the semi-diameter is set to 4.54 mm.

In this embodiment, the first lens 11 is a doublet lens, and the second lens 12 is a zigzag lens. The doublet lens and the lume lens can effectively reduce spherical aberration, and even reduce spherical aberration to zero.

In some embodiments, the light shielding member 20 is an aperture.

In some embodiments, the light shielding portion 21 has a black coating layer. Specifically, the blackened layer covers the entire light shielding portion 21 .

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

The radius of curvature of the incident surface 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.

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.

The radius of curvature of the incident surface 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.

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.

The third lens 31 is a zigzag lens, and the fourth lens 32 is a doublet lens.

In some embodiments, the dispersion 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 .

The present application and its implementations are described above, and this description is not limiting. What is shown in the drawings is only one of the implementations of the application, and the actual structure is not limited thereto. In a word, if a person of ordinary skill in the art is inspired by it, without departing from the purpose of the invention of the embodiment of the application, without creatively designing a structural method and embodiment similar to the technical solution, it shall belong to the implementation of the application. example of the scope of protection.

Claims (8)

1. A dispersion lens, characterized in that, comprising: The first lens group, the light-shielding member and the second lens group, wherein the first lens group is used to emit incident light to the light-shielding member, the light-shielding member includes a light-shielding part and a light-transmitting part, and the light-shielding part uses In order to block the central ray of the incident light, the marginal ray of the incident light is emitted to the second lens group through the light-transmitting part, and the second lens group converges the marginal ray to form a There is a one-to-one measurement spot for each wavelength. 2. The dispersion lens according to claim 1, wherein the first lens group comprises a first lens and a second lens. 3. The dispersion lens according to claim 2, wherein the first lens is a doublet lens, and the second lens is a lume lens. 4. The dispersion lens according to claim 3, wherein the light shielding member is a diaphragm. 5. The dispersion lens according to claim 3, wherein the light-shielding part has a black coating layer. 6. The dispersion lens according to any one of claims 4 or 5, wherein the second lens group comprises a third lens and a fourth lens. 7. The dispersion lens according to claim 6, wherein the third lens is a lume lens, and the fourth lens is a doublet lens. 8 . The dispersion lens according to claim 7 , further comprising a lens barrel for fixing the first lens group, the light shielding member and the second lens group.

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