Method for calibrating transmittance of optical lens

Abstract

A method for calibrating the transmittance of an optical lens, the method comprising: arranging a series of flat sheets on a spherical surface of a hemispherical coating fixture and coating the flat sheets by using the same process as that of a target lens (Step S1); measuring the transmittance of the coated surface of each flat sheet at the same target edge position corresponding to a target incident angle, wherein the target edge position is an edge position of a clear aperture of the target lens reserved for clamping by a matching coating fixture, and the edge position of each flat sheet clamped by the hemispherical coating fixture is consistent with the edge position of the target lens clamped by the matching coating fixture (Step S2); obtaining, by means of fitting on the basis of the measured edge transmittance of each flat sheet and coordinate information on the coating fixture a two-dimensional curve corresponding to the target incident angle of an included angle between a first connecting line and a second connecting line as a function of the transmittance during gradual change, wherein the first connecting line is a line connecting any coordinate point on the spherical surface of the coating fixture to the sphere center, the second connection line is a line connecting the vertex of the spherical surface of the coating fixture to the sphere center, and different target incident angles correspond to different two-dimensional curves (Step S3); and saving the two-dimensional curves as reference standards for improving or verifying the edge transmittance of the target lens for subsequent reference (Step S4).

Description

Method for calibrating the transmittance of optical lenses

[0001] This application claims priority to Chinese Patent Application No. 202510384576.0, filed on March 28, 2025, entitled "Method for Calibrating the Transmittance of Optical Lenses", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of optical technology, and more particularly to a method for calibrating the transmittance of optical lenses. Background Technology

[0003] In some applications, optical lenses require high uniformity of transmittance. For example, due to the curved surface of the lens, the coating thickness may be uneven during electron gun evaporation coating.

[0004] During the coating process of optical lenses, the coating thickness may be uneven due to the clamping of the fixture and / or the process itself, resulting in the transmittance of the edge part being lower than that of the center part.

[0005] Furthermore, in some harsh optical environments, in order to avoid uneven transmittance of coated lenses and other lenses when the incident light angle is too large, it is necessary to consider whether the transmittance of the edge part meets the requirements during the design process of optical products. However, there is currently no existing technology to achieve this goal, which has become a technical challenge in the industry. Summary of the Invention

[0006] The purpose of this invention is to disclose a method for calibrating the transmittance of an optical lens, in order to help improve or verify the edge transmittance of a target lens.

[0007] To achieve the above objectives, the optical lens transmittance calibration method disclosed in this invention includes: deploying a series of flat plates on the spherical surface of a hemispherical coating fixture; measuring the transmittance of the coating surface of each flat plate at the same target edge position corresponding to the target incident angle; the target edge position is the edge position reserved for clamping by the matching coating fixture for the light-transmitting aperture of the target lens, and the edge position of each flat plate clamped by the hemispherical coating fixture is consistent with the edge position of the target lens clamped by the matching coating fixture; fitting the measured edge transmittance of each flat plate and the coordinate information on the coating fixture to obtain a two-dimensional curve of the angle between the first line and the second line corresponding to the target incident angle as the transmittance gradually changes during the gradual change process; wherein, the first line is the line connecting any coordinate point on the spherical surface of the coating fixture to the center of the sphere, and the second line is the line connecting the vertex of the spherical surface of the coating fixture to the center of the sphere; and different target incident angles correspond to different two-dimensional curves; saving each two-dimensional curve as a reference standard for improving or verifying the edge transmittance of the target lens for future reference.

[0008] In one embodiment, the method of the present invention further includes: during the design process of applying the target lens to the target optical path product, after determining the series of solutions of the target lens in the target optical path product, obtaining the incident angle of the target edge corresponding to any solution, finding the two-dimensional curve corresponding to the incident angle, and determining the first angle between the line connecting the target edge position of the incident surface and the center of the sphere and the optical axis, and the second angle between the line connecting the target edge position of the exiting surface and the center of the sphere and the optical axis, then finding the transmittance corresponding to the first angle and the second angle on the two-dimensional curve, multiplying the two transmittances found, determining the edge transmittance of the current solution, and then comparing the edge transmittances corresponding to each solution to select the solution with the optimal edge transmittance.

[0009] In one embodiment, the method of the present invention further includes: during the design process of applying the target lens to the target optical path product, in the process of determining the series solution set of the target lens in the target optical path product, setting the constraint condition of edge transmittance, after obtaining the incident angle of the target edge corresponding to any design, finding the two-dimensional curve corresponding to the incident angle, and determining the first angle between the line connecting the target edge position of the incident surface and the center of the sphere and the optical axis, and the second angle between the line connecting the target edge position of the exiting surface and the center of the sphere and the optical axis, and then finding the transmittance corresponding to the first angle and the second angle on the two-dimensional curve, multiplying the two transmittances found, determining the edge transmittance of the current design, and then judging whether the transmittance result satisfies the constraint condition. If it does not satisfy the constraint condition, the current design is judged as an invalid design to prohibit it from being included in the series solution set of the target lens in the target optical path product.

[0010] In one embodiment, the method of the present invention further includes: during the design process of applying the target lens to the target optical path product, after determining the target transmittance of the target lens in the target optical path product and the incident angle of the target edge, allocating the curvature radii of the incident surface and the exit surface according to the two-dimensional curve corresponding to the incident angle so that the product of the transmittance of the two surfaces at the target edge is equal to or greater than the target transmittance.

[0011] In one embodiment, the cross-section of the flat plate in the method of the present invention is circular, and the target edge position of the target lens is 2 mm away from the outer contour line of the flat plate.

[0012] The present invention has the following beneficial effects: the calibration results after a series of processing steps can map different target lenses. Based on the gradual change of transmittance at each coordinate point on the incident and exit surfaces during actual use after the matching coating fixture is coated by the target process, it can accurately determine the transmittance of the incident and exit surfaces at the target edge of various flexibly variable target lenses at different beam incident angles. Thus, the overall transmittance of the target lens at the target edge can be reasonably verified or improved during the product design stage. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments 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.

[0014] Figure 1 is a schematic flowchart of the optical lens transmittance calibration method disclosed in an embodiment of the present invention.

[0015] Figure 2 is a schematic diagram of the distribution of the calibration flat sheet on the hemispherical coating fixture disclosed in the embodiment of the present invention.

[0016] Figure 3 is a schematic diagram of the optical path for measuring the transmittance of the coated surface of each flat piece at the same target edge position corresponding to the target incident angle, as disclosed in an embodiment of the present invention.

[0017] Figure 4 is a schematic diagram of the two-dimensional curves of the target edge transmittance and the included angle after fitting for two different incident angles of 10° and 30° disclosed in the embodiments of the present invention.

[0018] Figure 5 is a schematic diagram of the two-dimensional curves of the target edge transmittance and γ coefficient after being fitted to two different incident angles of 10° and 30°, as shown in Figure 4 after deformation. Detailed Implementation

[0019] 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, and 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] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1

[0022] This embodiment discloses a method for calibrating the transmittance of an optical lens, as shown in Figure 1, including the following steps:

[0023] Step S1: Deploy a series of flat sheets on the spherical surface of the hemispherical coating fixture.

[0024] In this step, the dimensions of the hemispherical coating fixture can typically be referenced to existing large-size lenses. Optionally, the radius of the hemispherical coating fixture can be 75mm. A flat sheet is a regular glass substrate with a horizontal coating surface and a circular cross-section.

[0025] In this step, the deployment of the series of flat sheets can be referred to Figure 2. Each dot 100 in Figure 2 represents the deployment position of the series of flat sheets from a top-down view. The different sized rings in Figure 2 are the ratio of the vertical distance between the corresponding coordinate point on the sphere and the line connecting the vertex to the center of the sphere (this line is the axis of symmetry of the hemispherical coating fixture) to the radius of the sphere. For ease of description, this embodiment defines this ratio as the "P value", as shown in Figure 2 as 0.3, 0.5, 0.7 and 0.9. When the flat sheet is located at the vertex (i.e., the center) of the coating fixture, the P value is 0, and the P value at the bottom edge of the coating fixture is 1. In actual deployment, the maximum P value at which flat sheets can be placed at the bottom is about 0.9. Generally, the closer the flat sheet is to the bottom edge of the coating fixture, the lower its transmittance.

[0026] Step S2: Measure the transmittance of the coated surface of each flat piece at the same target edge position corresponding to the target incident angle; the target edge position is the edge position reserved for clamping by the matching coating fixture when the light aperture of the target lens is the same as the edge position of the target lens being clamped by the matching coating fixture.

[0027] In this step, in order to improve the efficiency of mass production and control costs, the matching coating fixture for the target lens can be a large-diameter coating fixture with a bottom diameter of 1.1m. The shell outline of this large-diameter coating fixture is usually a partially hollow sphere, and its surface has several cavities for accommodating the coated lens and is equipped with clamping functions during the coating process.

[0028] In this step, the transmittance of the coated surface of each flat plate at the same target edge position corresponding to the target incident angle can be determined using the optical path shown in Figure 3. The emitted light from the laser 1 passes through two mirrors (first mirror 2 and second mirror 3), the main function of which is to simulate the galvanometer changing the scanning angle. By adjusting the angle of the second mirror 3 (the mirror rotates by 1°, and the light beam rotates by 2°), the angle of the incident light beam is adjusted. The flat plate 4 to be tested is moved horizontally so that the light beam is incident at a position of about 2 mm on the edge of the lens 6 (2 mm is the position of the coating fixture reserved at the edge of the light-transmitting aperture). The light power transmitted through the lens is measured by the power meter 5, and then the light power without passing through the test flat plate at this angle is measured. The ratio of the two is the edge transmittance of the lens.

[0029] Step S3: Based on the edge transmittance measured by each flat plate and the coordinate information on the coating fixture, fit the two-dimensional curve corresponding to the incident angle of the target: the angle between the first line and the second line gradually changes with the transmittance during the gradual change process; wherein, the first line is the line connecting any coordinate point on the spherical surface of the coating fixture and the center of the sphere, and the second line is the line connecting the vertex of the spherical surface of the coating fixture and the center of the sphere; and different incident angles of the target correspond to different two-dimensional curves.

[0030] In this step, as shown in Figure 4, the fitted two-dimensional curve essentially represents the distribution trend of transmittance at the same target edge position during the coating process as the angle gradually changes. Furthermore, those skilled in the art, inspired by this invention, can derive various representations of the distribution trend of transmittance at the same target edge position during the coating process as the angle gradually changes. For example, the angle between the first and second lines can be defined as... The γ coefficient is then defined as The fitted curves of the γ coefficient and transmittance corresponding to the two different incident angles of 10° and 30° are shown in Figure 5; such deformations are all equivalent substitutions and are still within the scope of protection of this invention.

[0031] Step S4: Save each two-dimensional curve as a reference standard for improving or verifying the edge transmittance of the target lens for future reference.

[0032] In this step, the methods of utilizing the calibrated two-dimensional curve include, but are not limited to, the following three methods:

[0033] Method 1: In the design process of applying the target lens to the target optical path product, after determining the series of solutions of the target lens in the target optical path product, obtain the incident angle of the target edge corresponding to any solution, find the two-dimensional curve corresponding to the incident angle, and determine the first angle between the line connecting the target edge position of the incident surface and the center of the sphere and the optical axis, and the second angle between the line connecting the target edge position of the exit surface and the center of the sphere and the optical axis. Then, find the transmittance corresponding to the first angle and the second angle on the two-dimensional curve, and determine the result of multiplying the two transmittances as the edge transmittance of the current solution. Then, by comparing the edge transmittances corresponding to each solution, the solution with the optimal edge transmittance is selected.

[0034] Method 2: In the design process of applying the target lens to the target optical path product, during the process of determining the series solution set of the target lens in the target optical path product, a constraint condition for edge transmittance is set. After obtaining the incident angle of the target edge corresponding to any design, the two-dimensional curve corresponding to the incident angle is found, and the first angle between the line connecting the target edge position of the incident surface and the center of the sphere and the optical axis, and the second angle between the line connecting the target edge position of the exit surface and the center of the sphere and the optical axis are determined. Then, the transmittance corresponding to the first angle and the second angle are found on the two-dimensional curve. The result of multiplying the two transmittances is determined as the edge transmittance of the current design. Then, it is determined whether the transmittance result meets the constraint condition. If it does not meet the constraint condition, the current design is judged as an invalid design and is prohibited from being included in the series solution set of the target lens in the target optical path product.

[0035] Method 3: In the design process of applying the target lens to the target optical path product, after determining the target transmittance and the incident angle of the target edge in the target optical path product, the curvature radii of the incident surface and the exit surface are allocated according to the two-dimensional curve corresponding to the incident angle so that the product of the transmittance of the two surfaces at the target edge is equal to or greater than the target transmittance.

[0036] In summary, the optical lens transmittance calibration method disclosed in the embodiments of the present invention has at least the following beneficial effects:

[0037] The calibration results after a series of processing steps can be mapped to different target lenses. Based on the target coating process after the matching coating fixture is coated, the transmittance of each coordinate point on the incident and exit surfaces during actual use can be gradually changed. This allows for the accurate determination of the transmittance of various target lenses at different incident angles of the beam at the target edge on the incident and exit surfaces. As a result, the overall transmittance of the target lens at the target edge can be reasonably verified or improved during the product design stage.

[0038] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for calibrating the transmittance of an optical lens, characterized in that, include: A series of flat plates are deployed on the spherical surface of a hemispherical coating fixture and coated using the same process as the target lens; The transmittance of the coated surface of each flat piece at the same target edge position corresponding to the target incident angle is measured; the target edge position is the edge position reserved for clamping by the light aperture of the target lens and the matching coating fixture, and the edge position of each flat piece clamped by the hemispherical coating fixture is consistent with the edge position of the target lens clamped by the matching coating fixture. Based on the edge transmittance measured by each flat plate and the coordinate information on the coating fixture, a two-dimensional curve is obtained corresponding to the incident angle of the target: the angle between the first line and the second line gradually changes with the transmittance during the gradual change process; wherein, the first line is the line connecting any coordinate point on the spherical surface of the coating fixture and the center of the sphere, and the second line is the line connecting the vertex of the spherical surface of the coating fixture and the center of the sphere; and different incident angles of the target correspond to different two-dimensional curves; Save each two-dimensional curve as a reference standard for improving the target lens or verifying the edge transmittance for future use.

2. The optical lens transmittance calibration method according to claim 1, characterized in that, Also includes: In the design process of applying the target lens to the target optical path product, after determining the series of solutions of the target lens in the target optical path product, the incident angle of the target edge corresponding to any solution is obtained, the two-dimensional curve corresponding to the incident angle is found, and the first angle between the line connecting the target edge position of the incident surface and the center of the sphere and the optical axis, and the second angle between the line connecting the target edge position of the exit surface and the center of the sphere and the optical axis are determined. Then, the transmittance corresponding to the first angle and the second angle is found on the two-dimensional curve, and the result of multiplying the two transmittances is determined as the edge transmittance of the current solution. Then, the solution with the optimal edge transmittance is selected by comparing the edge transmittances corresponding to each solution.

3. The optical lens transmittance calibration method according to claim 1, characterized in that, Also includes: In the design process of applying the target lens to the target optical path product, during the process of determining the series solution set of the target lens in the target optical path product, the constraint condition of edge transmittance is set. After obtaining the incident angle of the target edge corresponding to any design, the two-dimensional curve corresponding to the incident angle is found, and the first angle between the line connecting the target edge position of the incident surface and the center of the sphere and the optical axis, and the second angle between the line connecting the target edge position of the exit surface and the center of the sphere and the optical axis are determined. Then, the transmittance corresponding to the first angle and the second angle are found on the two-dimensional curve. The result of multiplying the two transmittances is determined as the edge transmittance of the current design. Then, it is judged whether the transmittance result meets the constraint condition. If it does not meet the constraint condition, the current design is judged as an invalid design and is prohibited from being included in the series solution set of the target lens in the target optical path product.

4. The optical lens transmittance calibration method according to claim 1, characterized in that, Also includes: In the design process of applying the target lens to the target optical path product, after determining the target transmittance and the incident angle of the target edge in the target optical path product, the curvature radii of the incident surface and the exit surface are allocated according to the two-dimensional curve corresponding to the incident angle so that the product of the transmittance of the two surfaces at the target edge is equal to or greater than the target transmittance.

5. The method for calibrating the transmittance of an optical lens according to any one of claims 1 to 4, characterized in that, The cross-section of the flat plate is circular, and the target edge of the target lens is located 2mm away from the outer contour line of the flat plate.

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