WO2023098349A1

WO2023098349A1 - Optical lens parameter measurement device and method

Info

Publication number: WO2023098349A1
Application number: PCT/CN2022/127616
Authority: WO
Inventors: 刘力威; 徐亮; 陈珂; 崔银川; 杨燕飞
Original assignee: 宁波法里奥光学科技发展有限公司
Priority date: 2021-11-30
Filing date: 2022-10-26
Publication date: 2023-06-08
Also published as: CN114199522A

Abstract

An optical lens parameter measurement device. The optical lens parameter measurement device comprises an optical interference detection unit, a refraction detection unit, and an interference signal detection unit; the optical interference detection unit comprises a coupling assembly (1), a first optical fiber arm (2), and a second optical fiber arm (3), a third optical fiber arm (4), a fourth optical fiber arm (5), a first light source (6), a first collimating lens (7), a second collimating lens (8), a movable reference mirror (9), a Hartmann diaphragm (10), a camera (11) and a measured lens (12); the refraction detection unit comprises a second light source (13), a third collimating lens (14), and a first beam splitting sheet (15); the interference signal detection unit comprises a fourth collimating lens (16), a second beam splitting sheet (17), a third light splitting sheet (18), a first optical filter (19), a second optical filter (20), a third optical filter (21), a first photoelectric detector (22), a second photoelectric detector (23), and a third photoelectric detector (24). Provided is an optical lens parameter measurement method executed on said optical lens parameter measurement device. High-precision measurement of the specific wavelength refractive index and the focal power of a finished lens can be realized without damaging the finished lens, the operation is simple, and the detection is rapid.

Description

Device and method for measuring optical lens parameters

technical field

The invention relates to the technical field of optical lens parameter detection, in particular to an optical lens parameter measurement device and method.

Background technique

Parameters such as focal length, central thickness, refractive index, and Abbe number are important parameters of optical lenses. In order to ensure good imaging quality of the optical system, it is necessary to accurately measure the refractive index of optical materials. Currently, high-precision measurement of the refractive index of optical glass materials is by the minimum deflection angle method. The minimum deflection angle method has high precision, a wide wavelength range, and is a direct measurement method, but the premise of the minimum deflection angle test method is that a prism needs to be made for light refraction, and the angle of the prism needs to be accurately tested. Such a prism is difficult to manufacture. , and the cycle is long; in addition, this method cannot test flat optical components, it is more suitable for glass manufacturers to test the refractive index samples of the same batch of glass, and it is not suitable for online high-precision testing of actual lens materials, especially for some special In certain applications, such as the detection of the refractive index of spectacle lenses, it is required to detect the refractive index without destroying the component without knowing the material of the optical component, and then determine its material properties.

At present, there are mainly two detection methods for measuring the refractive index of finished lenses. One is to perform reverse calculation based on the focal power formula, that is, to use mechanical precision measurement methods to measure the curvature of the front and rear surfaces, the central thickness, and the focal power of the lens. The focal power formula calculates the refractive index of the test wavelength. This method is complex and difficult to operate, and it is difficult to guarantee the measurement accuracy, and it is not suitable for the measurement of aspheric lenses; The refractive index of the medium in contact with the front and rear surfaces, such as placing the lens in a solution with a known refractive index, or attaching a flexible medium with a known refractive index to the front and rear surfaces of the lens, and testing the optical power of the lens in air and in solution respectively, according to The refractive index of the lens material can be calculated from the change of optical power and the refractive index of the solution. This method is also complicated to operate and difficult to detect.

Contents of the invention

The technical problem to be solved by the present invention is to provide an optical lens parameter measuring device that can measure the specific wavelength refractive index and focal power of the finished lens with high precision, simply and quickly without destroying the finished lens.

The technical solution adopted in the present invention is an optical lens parameter measurement device, including an optical interference detection unit, a refraction detection unit, and an interference signal detection unit, wherein:

The optical interference detection unit includes a coupling assembly, a first optical fiber arm, a second optical fiber arm, a third optical fiber arm, a fourth optical fiber arm, a first light source connected to the coupling assembly through the first optical fiber arm, and a first light source connected to the coupling assembly through the second optical fiber arm. The connected first collimating lens, the movable reference mirror located behind the first collimating lens, the second collimating lens connected to the coupling assembly through the third fiber arm, the lens under test, the Hartmann diaphragm plate and the camera;

The interference signal detection unit includes a fourth collimating lens, a second beam splitter, a third beam splitter, a first optical filter, a second optical filter, a third optical filter, a fourth optical filter, and a fourth optical fiber arm connected to the coupling assembly through a fourth optical fiber arm. A photodetector, a second photodetector and a third photodetector; the central wavelength setting of the first optical filter is set to nF, and the central wavelength setting of the second optical filter is set to ne , the central wavelength of the third filter is set to nC;

The refraction detection unit includes a second light source, a third collimating lens and a first beam splitter;

The light emitted by the first light source enters the coupling assembly through the first fiber arm, and is divided into two beams, one of which enters the first collimating lens through the second fiber arm, and is reflected by the movable reference mirror. The reflected light of the mirror is collected by the first collimating lens and enters the second fiber arm again, and enters the fourth fiber arm through the coupling assembly; another beam of light enters the second collimating lens through the third fiber arm, and is collimated by the second After the lens is focused, it is projected onto the Hartmann diaphragm, and then reflected by the upper surface of the Hartmann diaphragm, it returns to the original path, is focused by the second collimator lens and enters the third fiber arm, and then enters the first optical fiber arm through the coupling assembly. In the four-fiber arm, it is fused with the reflected light of the movable reference mirror. When the optical paths of the two beams of light fused together are equal, the interference phenomenon will occur, so as to calculate the refractive index of the lens under test;

The light entering the fourth fiber arm passes through the fourth collimating lens, and the fourth collimating lens outputs a parallel beam, and the parallel beam with a wavelength of nF is transmitted through the second beam splitter and the first optical filter in turn and enters the first In the photodetector, the parallel light beam with a wavelength of nC is reflected by the second beam splitter, transmitted by the third beam splitter and transmitted by the third filter into the third photodetector, and the parallel beam with a wavelength of ne passes through the second beam splitter in turn. sheet reflection, third light splitter reflection and second optical filter transmission into the second photodetector;

The light emitted by the second light source passes through the third collimating lens, and the parallel light beam emitted from the third collimating lens is reflected by the first beam splitter and enters the camera through the Hartmann diaphragm, forming an array of light spots in the camera. After the lens to be tested is inserted, the optical power of the lens to be tested is calculated through the offset of the light spot array.

The beneficial effects of the present invention are: adopting the above-mentioned optical lens parameter measuring device, the device can realize the high-precision measurement of the specific wavelength refractive index and optical power of the finished lens without damaging the finished lens, the operation is simple, and the detection is fast , and is suitable for the measurement of the refractive index of irregular surface lenses such as aspherical lenses and cylindrical lenses.

As a preference, when the optical paths of the two beams of light fused together are equal, an interference phenomenon will occur, and the optical path d1 from the upper surface of the lens under test to the second collimating lens is measured according to the position of the movable reference mirror when the interference occurs , the optical path d2 from the lower surface of the tested lens to the second collimator lens and the optical path D from the upper surface of the Hartmann diaphragm to the second collimator lens after inserting the tested lens, and at the same time obtain the When measuring the lens, the optical path D ₀ from the upper surface of the Hartmann diaphragm to the second collimating lens, and then calculate the refractive index of the measured lens:

Preferably, the first light source is a white light source with a spectral range of 450-680nm.

Preferably, the second light source is a green light source with a spectral range of 530-550nm.

Preferably, the second spectroscopic sheet and the third spectroscopic sheet are both long-wave pass spectroscopic sheets, the second spectroscopic sheet transmits light with a wavelength greater than 600nm, and reflects light with a wavelength less than 600nm; the third spectroscopic sheet transmits light with a wavelength greater than 500nm, For wavelengths less than 500nm light reflection.

As preferably, the first optical filter, the second optical filter and the third optical filter are all narrow-band optical filters, the center wavelength of the first optical filter is 655nm, the central wavelength of the second optical filter is 546nm, and the third optical filter The center wavelength of the light sheet is 486nm.

Preferably, the Abbe number Ve of the tested lens is:

Wherein, nF is the central wavelength of the first optical filter, ne is the central wavelength of the second optical filter, and nC is the central wavelength of the third optical filter.

A method for measuring optical lens parameters, the method is executed on the above-mentioned optical lens parameter measuring device, and the method includes the following steps:

S1. When testing the lens under test, place the lens under test above the Hartmann diaphragm, 3-6mm away from the Hartmann diaphragm;

S2. Use the camera to monitor the position of the light signal in real time, and judge whether the center of the lens under test is aligned with the center of the optical path. When the center of the lens under test is aligned, calculate the optical focus of the lens according to the offset degree of the light spot array in the camera. Spend;

S3, then control the horizontal movement of the movable reference mirror, when the optical path of the reflected light of the movable reference mirror is equal to the optical path of the reflected light reflected by the upper surface of the Hartmann diaphragm, optical interference will occur, Measure the optical distance d1 from the upper surface of the tested lens to the second collimator lens, the optical distance d2 from the lower surface of the tested lens to the second collimator lens and insert the measured lens according to the position of the movable reference mirror when the interference occurs The optical path D from the upper surface of the Hartmann diaphragm to the second collimator lens after the lens, and at the same time obtain the optical path D ₀ from the upper surface of the Hartmann diaphragm to the second collimator lens when the lens under test is not placed, and then Calculate the refractive index of the lens under test:

Using the above-mentioned optical lens parameter measurement method, this method can realize the high-precision measurement of the specific wavelength refractive index and optical power of the finished lens without destroying the finished lens, the operation is simple, the detection is fast, and it is suitable for aspheric lenses Refractive index measurement of irregular surface lenses such as cylindrical lenses.

Description of drawings

Fig. 1 is the structural representation of a kind of optical lens parameter measuring device of the present invention;

As shown in the figure: 1. Coupling component; 2. The first fiber arm; 3. The second fiber arm; 4. The third fiber arm; 5. The fourth fiber arm; 6. The first light source; 7. The first collimation Lens; 8. The second collimating lens; 9. The movable reference mirror; 10. The Hartmann diaphragm; 11. The camera; 12. The measured lens; 13. The second light source; 14. The third collimating lens; 15. The first beam splitter; 16. The fourth collimating lens; 17. The second beam splitter; 18. The third beam splitter; 19. The first filter; 20. The second filter; 21. The third filter light sheet; 22, the first photodetector; 23, the second photodetector; 24, the third photodetector.

Detailed ways

The invention will be further described below with reference to the accompanying drawings and in combination with specific embodiments, so that those skilled in the art can implement it by referring to the description, and the protection scope of the present invention is not limited to the specific embodiments.

Those skilled in the art should understand that, in the disclosure of the present invention, the terms "vertical", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientation or positional relationship indicated by "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present invention and The above terms should not be construed as limiting the present invention because the description is simplified rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation.

The present invention relates to an optical lens parameter measurement device, as shown in Figure 1, comprising an optical interference detection unit, a refraction detection unit and an interference signal detection unit, wherein:

The optical interference detection unit includes a coupling assembly 1, a first fiber arm 2, a second fiber arm 3, a third fiber arm 4, a fourth fiber arm 5, a first light source 6 connected to the coupling assembly 1 through the first fiber arm 2, The first collimating lens 7 connected to the coupling assembly 1 through the second fiber arm 3, the second collimating lens 8 connected to the coupling assembly 1 through the third fiber arm 4, the movable reference behind the first collimating lens 7 mirror 9, a Hartmann diaphragm 10 on the same vertical optical axis as the second collimating lens 8, a camera 11 on the same vertical optical axis as the second collimating lens 8, and a second collimating lens 8 and The measured lens 12 between the Hartmann aperture plates 10; the light emitted by the first light source 6 enters the coupling assembly 1 through the first fiber arm 2, and is divided into two beams of light, one of which passes through the second fiber arm 3 into the first collimator lens 7, and then reflected by the movable reference mirror 9, the reflected light of the movable reference mirror 9 is collected by the first collimator lens 7 and then enters the second fiber arm 3, and enters the second optical fiber arm 3 through the coupling assembly 1. In the four-fiber arm 5; another bundle of light enters the second collimator lens 8 through the third fiber arm 4, is projected onto the Hartmann diaphragm 10 after being focused by the second collimator lens 8, and is then captured by the Hartmann light The upper surface of the diaphragm 10 returns to the same path after being reflected, is focused by the second collimator lens 8 into the third fiber arm 4, and then enters the fourth fiber arm 5 through the coupling assembly 1, so as to be connected with the movable reference mirror 9 The reflected light rays are fused together, and interference phenomenon will occur when the optical paths of the two beams of light fused together are equal, so as to calculate the refractive index of the measured lens 12;

As shown in Figure 1, the refractive detection unit includes a second light source 13, a third collimator lens 14 located on the same horizontal optical axis as the second light source 13, and a first beam splitter 15, and the first beam splitter 15 is positioned at the Between the measuring mirror 12 and the second collimating lens 8, the light emitted by the second light source 13 becomes a parallel beam after passing through the third collimating lens 14, and the parallel beam emitted from the third collimating lens 14 is reflected by the first beam splitter 15 After entering into the camera 11 through the Hartmann aperture plate 10, an array of light spots is formed in the camera 11. When the lens under test 12 is inserted, the optical power of the lens under test 12 is calculated through the offset of the spot array;

As shown in Figure 1, the interference signal detection unit includes a fourth collimator lens 16 connected to the coupling assembly 1 through a fourth fiber arm 5, a second beam splitter 17, a third beam splitter 18, a first filter with a center wavelength of nF An optical sheet 19, a second optical filter 20 whose central wavelength is ne, a third optical filter 21 whose central wavelength is nC, a first photodetector 22, a second photodetector 23, and a third photodetector 24; Four collimating lenses 16, the second beam splitter 17, the first filter 19 and the first photodetector 22 are located on the same horizontal optical axis, the second beam splitter 17, the third beam splitter 18, the third filter 21 And the third photodetector 24 is located on the same vertical optical axis, and the third beam splitter 18, the second optical filter 20 and the second photodetector 23 are located on the same horizontal optical axis; the light entering the fourth optical fiber arm 5 Through the fourth collimator lens 16, the parallel light beam is output by the fourth collimator lens 16, and the parallel light beam with a wavelength of nF is transmitted through the second beam splitter 17 and the first optical filter 19 into the first photodetector 22 in turn. , the parallel light beam with a wavelength of nC is reflected by the second beam splitter 17, transmitted by the third beam splitter 18, and transmitted by the third filter into the third photodetector 24, and the parallel beam with a wavelength of ne passes through the second beam splitter in turn 17 reflection, the third light splitter 18 reflection and the second filter 20 transmission into the second photodetector 23 .

Using the above-mentioned optical lens parameter measurement device, the device can realize high-precision measurement of specific wavelength refractive index and optical power of the finished lens without destroying the finished lens. The operation is simple, the detection is fast, and it is non-contact detection. The method is applicable to the measurement of the refractive index of irregular surface lenses such as aspherical lenses and cylindrical lenses.

When the optical paths of the two beams of light fused together are equal, an interference phenomenon will occur. According to the position of the movable reference mirror 9 when the interference occurs, the optical path d1 from the upper surface of the lens under test 12 to the second collimator lens 8 is measured. , the optical path d2 from the lower surface of the tested lens 12 to the second collimating lens 8 and the optical path D from the upper surface of the Hartmann diaphragm 10 to the second collimating lens 8 after the tested lens 12 is inserted, and at the same time Obtain the optical path D ₀ from the upper surface of the Hartmann diaphragm 10 to the second collimating lens 8 when there is no tested lens 12, and then calculate the refractive index of the tested lens 12:

The wavelengths of light are different, and the values of the variables d1, d2, _D0 and D are different, that is, the positions of the interference signals measured by the detectors D1, D2 and D3 are different.

The first light source 6 is a white light source with a spectral range of 450-680nm.

The second light source 13 is a green light source with a spectral range of 530-550nm.

The second beam splitter 17 and the third beam splitter 18 are both long-wave pass beam splitters, the second beam splitter 17 transmits light with a wavelength greater than 600nm, and reflects light with a wavelength less than 600nm; the third beam splitter 18 transmits light with a wavelength greater than 500nm , for light reflections with wavelengths less than 500nm.

The first optical filter 19, the second optical filter 20 and the third optical filter 21 are all narrow-band optical filters, the central wavelength of the first optical filter 19 is 655nm, the central wavelength of the second optical filter 20 is 546nm, and the central wavelength of the second optical filter 20 is 546nm. The central wavelength of the three optical filters 21 is 486nm.

The Abbe number Ve of the measured lens 12 is:

Wherein, nF is the central wavelength of the first optical filter 19 , ne is the central wavelength of the second optical filter 20 , and nC is the central wavelength of the third optical filter 21 .

S1, as shown in Figure 1, when the lens under test 12 is tested, the lens under test 12 is placed above the Hartmann diaphragm 10, 3-6mm away from the Hartmann diaphragm;

S2. Monitor the position of the optical signal in real time through the camera 11 to determine whether the center of the lens under test 12 is aligned with the center of the optical path. When the center of the lens under test 12 is aligned, calculate according to the degree of offset of the light spot array in the camera 11 the focal power of the lens;

S3, then control the movable reference mirror 9 to move horizontally, when the optical path of the reflected light of the movable reference mirror 9 is equal to the optical path of the reflected light reflected from the upper surface of the Hartmann diaphragm plate 10, it will occur Optical interference phenomenon, according to the position of the movable reference mirror 9 when the interference occurs, the optical path d1 from the upper surface of the tested lens 12 to the second collimating lens 8, and the optical distance d1 from the lower surface of the tested lens 12 to the second collimating lens are measured. The optical path d2 of 8 and the optical path D from the upper surface of the Hartmann diaphragm 10 to the second collimator lens 8 after the lens under test 12 is inserted are obtained according to the calibration of the optical system when the lens under test 12 is not inserted. The optical path D ₀ from the upper surface of the Terman diaphragm 10 to the second collimating lens 8, and then calculate the refractive index of the measured lens 12:

Claims

An optical lens parameter measurement device, characterized in that it includes an optical interference detection unit, a refraction detection unit, and an interference signal detection unit, wherein:

The optical interference detection unit includes a coupling assembly (1), a first fiber arm (2), a second fiber arm (3), a third fiber arm (4), a fourth fiber arm (5), and through the first fiber arm (2) ) the first light source (6) connected to the coupling assembly (1), the first collimating lens (7) connected to the coupling assembly (1) through the second fiber arm (3), and the first collimating lens (7) The movable reference mirror (9) at the rear, the second collimating lens (8) connected to the coupling assembly (1) through the third fiber arm (4), the lens under test (12), the Hartmann diaphragm (10 ) and camera (11);

The interference signal detection unit includes a fourth collimating lens (16), a second beam splitter (17), a third beam splitter (18), a first filter Sheet (19), second optical filter (20), third optical filter (21), first photodetector (22), second photodetector (23) and third photodetector (24); The central wavelength of the first optical filter (19) is set as nF, the central wavelength of the second optical filter (20) is set as ne, and the central wavelength of the third optical filter (21) is set as nF. set as nC;

The refraction detection unit includes a second light source (13), a third collimator lens (14) and a first beam splitter (15);

The light emitted by the first light source (6) enters the coupling assembly (1) through the first fiber arm (2), and is divided into two beams, one of which enters the first collimating lens ( 7), and then reflected by the movable reference mirror (9), the reflected light of the movable reference mirror (9) is collected by the first collimating lens (7) and enters the second fiber arm (3) again, through the coupling assembly (1 ) into the fourth fiber arm (5); another beam of light enters the second collimator lens (8) through the third fiber arm (4), and is projected to Hartmann after being focused by the second collimator lens (8). On the diaphragm plate (10), it is reflected by the upper surface of the Hartmann diaphragm plate (10) and returns to the original path, and is focused by the second collimator lens (8) into the third fiber arm (4), and then passes through the The coupling component (1) enters into the fourth fiber arm (5) to merge with the reflected light of the movable reference mirror (9), and interference phenomenon occurs when the optical paths of the two beams of light merged together are equal , so as to calculate the refractive index of the measured lens (12);

The light entering the fourth fiber arm (5) passes through the fourth collimating lens (16), and the fourth collimating lens (16) outputs a parallel beam, and the parallel beam with a wavelength of nF passes through the second beam splitter (17) in sequence Transmission and the first optical filter (19) are transmitted into the first photodetector (22), and the parallel light beams with a wavelength of nC are reflected by the second light splitter (17), transmitted by the third light splitter (18) and transmitted by the second light splitter (18) in turn. The three filter plates are transmitted into the third photodetector (24), and the parallel light beams with a wavelength of ne are reflected by the second light splitter (17), reflected by the third light splitter (18) and second light filter (20). transmission into the second photodetector (23);

The light that the second light source (13) sends passes through the 3rd collimating lens (14), and the parallel light beam that goes out from the 3rd collimating lens (14) passes through the Hartmann aperture plate ( 10) Enter into the camera (11), form an array of light spots in the camera (11), when the lens under test (12) is inserted, calculate the optical power of the lens under test (12) through the offset of the array of light spots .
A kind of optical lens parameter measurement device according to claim 1, is characterized in that: the refractive index of measured lens (12) is expressed as:
Wherein, d1 is expressed as the optical path from the upper surface of the measured lens (12) to the second collimating lens (8) measured according to the position of the movable reference mirror (9) when interference phenomenon occurs; d2 is expressed as when interference phenomenon occurs The optical path from the lower surface of the measured lens (12) to the second collimating lens (8) during the interference phenomenon; The optical path of the second collimating lens (8); D 0 represents the optical path from the upper surface of the Hartmann diaphragm sheet (10) to the second collimating lens (8) when the measured lens (12) is not inserted.
The device for measuring optical lens parameters according to claim 1, characterized in that: the first light source (6) is a white light source with a spectral range of 450-680nm.
The device for measuring optical lens parameters according to claim 1, characterized in that: the second light source (13) is a green light source with a spectral range of 530-550nm.
A kind of optical lens parameter measurement device according to claim 1, it is characterized in that: the second beam splitter (17) and the third beam splitter (18) are both long-wave pass beam splitters, and the second beam splitter (17) has a relatively high frequency for wavelength Light greater than 600nm is transmitted, and light with a wavelength less than 600nm is reflected; the third light splitter (18) transmits light with a wavelength greater than 500nm, and reflects light with a wavelength less than 500nm.
A device for measuring optical lens parameters according to claim 5, characterized in that: the first filter (19), the second filter (20) and the third filter (21) are all narrow-band filters sheet, the central wavelength of the first optical filter (19) is 655nm, the central wavelength of the second optical filter (20) is 546nm, and the central wavelength of the third optical filter (21) is 486nm.
A kind of optical lens parameter measurement device according to claim 1, is characterized in that: the Abbe number Ve of the measured lens (12) is:
Wherein, nF is the central wavelength of the first optical filter (19), ne is the central wavelength of the second optical filter (20), and nC is the central wavelength of the third optical filter (21).
A method for measuring optical lens parameters, the method is performed on an optical lens parameter measuring device according to any one of claims 1 to 7, and the method includes the following steps:

S1, when the tested lens (12) is tested, the tested lens (12) is placed above the Hartmann diaphragm (10), 3-6mm away from the Hartmann diaphragm;

S2, monitor the light signal position in real time by the camera (11), judge whether the center of the lens under test (12) is aligned with the center of the light path, after the center of the lens under test (12) is aligned, according to the light in the camera (11) The degree of offset of the point array to calculate the optical power of the lens;

S3, then control the movable reference mirror (9) to move horizontally, when the optical path of the reflected light of the movable reference mirror (9) and the optical path of the reflected light reflected by the upper surface of the Hartmann diaphragm (10) When they are equal, optical interference phenomenon will occur, and the optical distance d1 from the upper surface of the measured lens (12) to the second collimating lens (8), measured The optical distance d2 from the lower surface of the lens (12) to the second collimator lens (8) and the distance from the upper surface of the Hartmann diaphragm (10) to the second collimator lens (8) after inserting the measured lens (12) Optical path D, obtain the optical path D 0 from the upper surface of the Hartmann diaphragm (10) to the second collimating lens (8) when there is no measured lens (12), and then calculate the measured lens (12) Refractive index: