Microobjective numerical aperture measurement method and device

Abstract

The invention relates to the technical field of microscopes, discloses a method and a device for measuring the numerical aperture of a microscope objective, and aims to solve the problems of high operation difficulty and large measurement error in measurement of the conventional method. The method comprises the steps that parallel light enters from one side of an object plane to be measured, and a convergent conical light beam and a divergent conical light beam which are symmetrical in cone angle are obtained on the two sides of a working face on one side of the object plane of the object plane; based on the divergent conical light beam, acquiring diameter data and section spacing data of two adjacent sections perpendicular to an optical axis; on the basis of diameter data and section distance data of two adjacent sections of the divergent conical light beam, a numerical aperture measurement value of the objective lens to be measured is obtained through the calculation method; the method for measuring the numerical aperture of the microscope objective is simple in operation, reduces the operation difficulty of measuring the numerical aperture of the microscope objective, and improves the measurement accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of microscopes, and in particular to a method and a device for measuring the numerical aperture of a microscope objective lens. Background Art

[0002] Microscopic imaging technology has a wide range of applications in the fields of medicine, metallurgy, biotechnology, pharmaceuticals, and testing. As an important component of the microscopic imaging system, the quality of the optical parameters of the microscope objective directly affects the image quality and resolution of the microscopic imaging system. The numerical aperture of the microscope objective is an important parameter for measuring the light collection ability and resolution of the objective. It is determined by the product of the refractive index of the medium between the object and the objective and the sine value of half the aperture angle of the objective. Accurate measurement of the numerical aperture parameters of the microscope objective is an important method to judge whether the performance of the microscope objective is consistent with the theoretical design.

[0003] At present, a numerical aperture meter is commonly used to measure the numerical aperture parameters of microscope objectives. The microscope objective is focused on the slit on the numerical aperture meter, and the human eye sees the microscope objective exit pupil through the small hole diaphragm from the eyepiece end of the microscope. The handle of the numerical aperture meter is pushed to move the crosshairs until the intersection of the crosshairs is located at the left and right boundaries of the observed exit pupil. The readings of the numerical aperture meter are read when the intersection of the crosshairs is located at the left and right boundaries of the microscope objective exit pupil, and the arithmetic mean of the two readings is calculated as the numerical aperture measurement value. For objectives with large numerical apertures, auxiliary objectives need to be added for measurement. This method is difficult to operate during measurement and requires high skills of the user. In addition, the measurement value reading error caused by the operation is large, and it is difficult to achieve automatic measurement. Summary of the invention

[0004] The present application provides a method and device for measuring the numerical aperture of a microscope objective lens, which are used to achieve simple operation, reduce the operational difficulty of measuring the numerical aperture of a microscope objective lens, and improve the measurement accuracy;

[0005] In order to solve the above technical problems, the present invention is implemented according to the following technical solutions:

[0006] The present invention provides a method for measuring the numerical aperture of a microscope objective lens, comprising:

[0007] A parallel light is incident from one side of the image plane of the object to be measured, and a converging conical light beam and a diverging conical light beam with symmetrical cone angles are obtained on both sides of the working surface on the side of the object plane;

[0008] Based on the divergent conical light beam, obtaining diameter data and cross-section spacing data of two adjacent cross-sections perpendicular to the optical axis;

[0009] Based on the diameter data and the cross-section spacing data of two adjacent cross-sections of the divergent conical light beam, the numerical aperture measurement value of the objective lens to be measured is obtained by the following calculation method:

[0010]

[0011] Where: n is the refractive index of the medium on the object side of the objective lens to be measured;

[0012] D1—Cone beam measurement position 1 cross-sectional diameter;

[0013] D2—conical beam cross-sectional diameter at measurement position 2;

[0014] L—The distance between the conical beam section at measurement position 1 and the section at measurement position 2.

[0015] The present invention also provides a microscope objective numerical aperture measuring device, comprising:

[0016] Measuring light source, used to obtain parallel light;

[0017] A measuring module, used for obtaining a cross section of the divergent conical light beam perpendicular to the optical axis and measuring diameter data of the cross section;

[0018] A displacement module, used to obtain data of adjacent sections and section spacing of the divergent conical light beam perpendicular to the optical axis;

[0019] The measuring light source, the objective lens to be measured, and the measuring module are sequentially arranged along the main optical axis, the optical axis of the measuring light source and the optical axis of the objective lens to be measured are parallel to the main optical axis, and the measuring surface of the measuring module is perpendicular to the main optical axis;

[0020] According to a microscope objective numerical aperture measuring device provided by the present invention, a possible implementation method is that the objective lens to be measured is set on a displacement module, the measuring module is fixed in position, and the displacement module is moved so that the measuring module obtains two adjacent cross sections of the divergent conical light beam perpendicular to the optical axis and measures the diameter data thereof;

[0021] According to a microscope objective numerical aperture measuring device provided by the present invention, a possible implementation method is that the measuring module is arranged on a displacement module, the objective lens to be measured is fixed at a fixed position, and the displacement module is moved so that the measuring module obtains two adjacent cross sections of the divergent conical light beam perpendicular to the optical axis and measures the diameter data thereof;

[0022] The positive and progressive effects of the present invention are:

[0023] The present invention provides a method and device for measuring the numerical aperture of a microscope objective lens, which improves the measurement accuracy of the numerical aperture of the microscope objective lens, reduces the operational difficulty of users during measurement, simplifies the operation process, and improves the measurement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of a method for measuring the numerical aperture of a microscope objective provided by the present invention;

[0025] Figure 2 A schematic diagram of the principle of a method for measuring the numerical aperture of a microscope objective provided by the present invention;

[0026] Figure 3 A ruler measurement effect diagram of a microscope objective numerical aperture measurement method provided by the present invention;

[0027] Figure 4 A pixel measurement effect diagram of a microscope objective numerical aperture measurement method provided by the present invention;

[0028] Figure 5 A schematic structural diagram of a microscope objective numerical aperture measuring device provided by the present invention;

[0029] Figure 6 The present invention provides a schematic structural diagram of a device for measuring the numerical aperture of a microscope objective lens.

[0030] Description of labels:

[0031] 111, parallel light; 112, objective lens to be measured; 113, converging conical light beam; 114, diverging conical light beam; 121, first cross section; 122, second cross section; 123, first circular light spot; 124, second circular light spot; 210, measuring light source; 220, measuring module; 230, displacement module. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] In order to keep the following description of the embodiments of the present invention clear and concise, the present invention omits detailed descriptions of some known functions and known components.

[0035] Combine the following Figure 1 , Figure 2 , Figure 3 and Figure 4 The present invention describes the method for measuring the numerical aperture of a microscope objective lens:

[0036] like Figure 1 As shown, the method for measuring the numerical aperture of a microscope objective lens includes: step 110, step 120, and step 130;

[0037] Step 110, a parallel light 111 is incident from the image plane side of the objective lens 112 to be tested and a converging conical light beam 113 and a diverging conical light beam 114 with symmetrical cone angles are obtained on both sides of the working surface on the object plane side;

[0038] In this step, the objective lens 112 to be measured is a dry objective lens that needs to be measured for numerical aperture;

[0039] The converging conical light beam 113 and the diverging conical light beam 114 are the outgoing light beams of the parallel light 111 through the object lens 112 to be measured;

[0040] It can be understood that, in the actual implementation process, the optical axis of the parallel light 111 is arranged parallel to the optical axis of the objective lens 112 to be measured, and the incident cross section of the parallel light perpendicular to the optical axis completely covers the light aperture on the image plane side of the objective lens 112 to be measured, and the incident cross section is preferably larger than the light aperture;

[0041] Step 120, based on the divergent conical light beam 114, measuring the diameter data D1, D2 and the cross-section spacing data L of two adjacent cross sections perpendicular to the optical axis;

[0042] In this step, the cross section of the divergent conical light beam 114 perpendicular to the optical axis is a circular spot that can be used for measurement;

[0043] Two adjacent cross sections perpendicular to the optical axis include a first cross section 121 and a second cross section 122. The first cross section 121 corresponds to a first circular light spot 123, and diameter data D1 is obtained by measurement. The second cross section 122 corresponds to a second circular light spot 124, and diameter data D2 is obtained by measurement. The diameter data measurement may be one of the methods such as a ruler measurement with a scale, an image sensor pixel measurement, etc.

[0044] The cross-section spacing data L is the relative position difference between the measurement position of the first cross section 121 and the measurement position of the second cross section 122. The cross-section spacing measurement can be performed by a magnetic scale measurement, a grating scale measurement, an encoder measurement, or the like.

[0045] It can be understood that, in the actual implementation process, in order to achieve the best measurement result, the boundaries of the first circular light spot 123 and the second circular light spot 124 corresponding to the measurement position of the first cross section 121 and the measurement position of the second cross section 122 should be clear and sharp, and the diameter difference between the two should be obvious, wherein, as the nominal value of the numerical aperture of the objective lens 111 to be measured increases, the distance L between the measurement position of the first cross section 121 and the measurement position of the second cross section 122 will decrease;

[0046] Step 130, based on the diameter data and the cross-section spacing data of two adjacent cross-sections of the divergent conical light beam 114, the numerical aperture measurement value of the objective lens 112 to be measured is obtained by the following calculation method:

[0047]

[0048] Where: n-the refractive index of the medium on the object side of the objective lens to be measured;

[0049] D1-conical beam cross-sectional diameter at measurement position 1;

[0050] D2-conical beam cross-sectional diameter at measurement position 2;

[0051] L - The distance between the section at measurement position 1 and the section at measurement position 2 of the conical beam.

[0052] The numerical aperture measuring device of a microscope objective lens provided by the present invention is described below. The numerical aperture measuring device of a microscope objective lens described below and the numerical aperture measuring method of a microscope objective lens described above can be referred to each other.

[0053] like Figure 5 and Figure 6 The microscope objective numerical aperture measuring device shown includes: a measuring light source 210, a measuring module 220, and a displacement module 230;

[0054] A measuring light source 210, used to obtain parallel light 111;

[0055] A measuring module 220, for obtaining a cross section of the divergent conical light beam 114 perpendicular to the optical axis and measuring diameter data of the cross section;

[0056] The displacement module 230 is used to obtain the adjacent cross sections and the cross section spacing data of the divergent conical light beam 114 perpendicular to the optical axis;

[0057] Among them, the measuring light source 210, the objective lens 220 to be measured, and the measuring module 230 are sequentially arranged along the main optical axis, the optical axis of the measuring light source 210 and the optical axis of the objective lens 112 to be measured are parallel to the main optical axis, and the measuring surface of the measuring module 230 is perpendicular to the main optical axis;

[0058] In some embodiments, the displacement module 220 is used to move the objective lens 112 to be tested, and the objective lens 112 to be tested is set on the displacement module 220. The measurement module 230 is fixed in position and does not move. Moving the displacement module 220 enables the measurement module 230 to obtain two adjacent cross-sections of the divergent conical light beam 114 perpendicular to the optical axis and measure their diameter data.

[0059] In some embodiments, the displacement module 220 is used to move the measurement module 230. The measurement module 230 is set on the displacement module 220. The objective lens 112 to be measured is fixed in position. Moving the displacement module 220 enables the measurement module 230 to obtain two adjacent cross-sections of the divergent conical light beam 114 perpendicular to the optical axis and measure their diameter data.

[0060] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and some of the units may be selected for connection according to actual needs to achieve the purpose of the present embodiment.

[0061] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for measuring the numerical aperture of a microscope objective lens, characterized in that: include: The parallel light is incident from the mirror side of the object to be measured and the cone angle symmetry is obtained on both sides of the working surface on the object side. Converging cone beams and diverging cone beams; Based on the divergent conical light beam, obtaining diameter data and cross-section spacing data of two adjacent cross-sections perpendicular to the optical axis; Based on the diameter data and the cross-section spacing data of two adjacent cross-sections of the divergent conical light beam, the numerical aperture measurement value of the objective lens to be measured is obtained by the following calculation method: Where: n-the refractive index of the medium on the object side of the objective lens to be measured; D1-conical beam cross-sectional diameter at measurement position 1; D2-conical beam cross-sectional diameter at measurement position 2; L - The distance between the section at measurement position 1 and the section at measurement position 2 of the conical beam.

2. A device for measuring the numerical aperture of a microscope objective lens, characterized in that: include: Measuring light source, used to obtain parallel light; A measuring module, used for obtaining a cross section of the divergent conical light beam perpendicular to the optical axis and measuring diameter data of the cross section; A displacement module, used for acquiring data of adjacent sections and section spacing of the divergent conical light beam perpendicular to the optical axis; The measuring light source, the objective lens to be measured and the measuring module are sequentially arranged along the main optical axis. The optical axes of the measuring light source and the objective lens to be measured are parallel to the main optical axis, and the measuring surface of the measuring module is perpendicular to the main optical axis.

3. A microscope objective numerical aperture measuring device according to claim 2, characterized in that: The objective lens to be measured is arranged on the displacement module, the measuring module is fixed in position and does not move, and the displacement module is moved so that the measuring module obtains two adjacent cross sections of the divergent conical light beam perpendicular to the optical axis and measures the diameter data thereof.

4. The device for measuring the numerical aperture of a microscope objective lens according to claim 2, characterized in that: The measuring module is arranged on the displacement module, the objective lens to be measured is fixed in position and does not move, and the displacement module is moved so that the measuring module obtains two adjacent cross sections of the divergent conical light beam perpendicular to the optical axis and measures the diameter data thereof.

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