Lens refractive index measuring device and measuring method thereof

Abstract

The present invention discloses a lens refractive index measuring device, comprising a diopter measuring module, a confocal reflection measuring module and a lens to be measured; the diopter measuring module is used to detect the diopter of the lens to be measured, and the confocal reflection measuring module is used to detect the confocal reflection position of the upper and lower surfaces of the lens to be measured. The lens refractive index of the lens to be measured can be obtained by the measuring device without destroying the lens, and the operation is simple and the detection is fast. Moreover, the device is applicable to the refractive index measurement of ordinary lenses, aspherical lenses, cylindrical lenses and other irregular surface lenses. The lens refractive index measuring method of the present invention is simple to operate, has fast detection and high measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of optical measurement, and more specifically to a lens refractive index measuring device and a measuring method thereof. Background Art

[0002] The refractive index parameter is an important parameter indicator of optical lenses. In order to ensure that the optical system has good imaging quality, it is necessary to accurately measure the refractive index of optical materials. At present, the high-precision measurement of the refractive index of optical glass materials is carried out through the minimum deviation angle method. The minimum deviation angle method has high precision, a large wavelength range, and is a direct measurement, but the premise of the minimum deviation angle test method is that a prism needs to be made to refract light, and the angle of the prism needs to be accurately tested. Such a prism is difficult to make and takes a long time to make; 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, but not suitable for online high-precision testing of actual lens materials. Especially in some special applications, such as the refractive index detection of eyeglass lenses, when the material of the optical component is unknown, it is required not to destroy the component to achieve its refractive index detection, and then determine its material properties.

[0003] Currently, there are two main methods for measuring the refractive index of finished lenses. One is to perform reverse calculation based on the optical power formula, that is, to use mechanical precision measurement methods to measure the upper and lower surface curvatures, center thickness and lens optical power, and calculate the refractive index of the test wavelength based on the optical power. This method is complex and difficult to operate, and it is difficult to ensure measurement accuracy, and it is not suitable for aspheric lens measurement. The other method is to change the "environmental" refractive index method, that is, by changing the refractive index of the medium in contact with the upper and lower surfaces of the lens, 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 upper and lower surfaces of the lens, and testing the optical power of the lens in the air and in the solution respectively. The refractive index of the lens material can be calculated based on the change in optical power and the refractive index of the solution. This method is also complex to operate and difficult to detect. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a lens refractive index measuring device, which has the advantages of simple operation, fast detection and high measurement accuracy.

[0005] The technical solution of the present invention is to provide a lens refractive index measuring device, including a diopter measuring module, a confocal reflection measuring module and a lens to be measured; the diopter measuring module includes a first light source module, a first collimating lens, a Hartmann aperture and a first photodetector; the light emitted by the first light source module becomes a parallel light beam after passing through the first collimating lens; the parallel light beam passes through the lens to be measured and the Hartmann aperture and is incident on the first photodetector; the confocal reflection measuring module includes a second light source, a second photodetector, a Y-type optical fiber, a lens group and a first beam splitter; the light emitted by the second light source is coupled to the Y-type optical fiber from the first port The first beam splitter is arranged between the first collimating lens and the lens to be measured, and the converged light is then reflected by the first beam splitter and focused at the lens to be measured; the second port and the lens group are both installed on a moving component, and the moving component moves back and forth along the optical axis, and the light beam can be focused on the upper surface of the Hartmann aperture plate and the upper and lower surfaces of the lens to be measured, respectively. When focusing, the reflected light will return to the second port along the original path, and after propagation through the optical fiber, it will be emitted from the third port of the Y-type optical fiber to the second photodetector.

[0006] After adopting the above structure, the lens refractive index measuring device of the present invention has the following advantages compared with the prior art:

[0007] The lens refractive index measuring device of the present invention comprises a diopter measuring module, a confocal reflection measuring module and a lens to be measured; the diopter measuring module is used to detect the diopter of the lens to be measured, and the confocal reflection measuring module is used to detect the confocal reflection position of the upper and lower surfaces of the lens to be measured. The lens refractive index of the lens to be measured can be obtained through the measuring device without destroying the lens, and the operation is simple and the detection is fast. Moreover, the measuring device is suitable for measuring the refractive index of lenses with irregular surfaces such as ordinary lenses, aspherical lenses, cylindrical lenses, etc.

[0008] As an improvement, the measuring device also includes an optical thickness measuring module; the optical thickness measuring module includes a second light source module, a second collimating lens, a focusing lens, a second beam splitter, a third beam splitter, a reflector and a third photodetector; the light emitted by the second light source module becomes a parallel light beam after passing through the second collimating lens, and the parallel light beam is irradiated on the second beam splitter after passing through the focusing lens; it enters the main light path after being reflected by the second beam splitter; it is then divided into two beams of light after passing through the third beam splitter, one of which is reflected on the reflector, and then reflected back by the reflector along the original path, and part of the light is transmitted through the third beam splitter and enters the third photodetector; the other beam of light is transmitted through the third beam splitter and reflected along the original path by the upper surface of the Hartmann aperture plate, and the reflected light is reflected through the third beam splitter and enters the third photodetector; when the two parts of light reflected and transmitted by the third beam splitter are reflected and then enter the third photodetector at the same time; the reflector is installed on the moving component and moves synchronously with the second port and the lens group, and the reflector is moved, and when the two parts of light reflected and transmitted by the third beam splitter enter the third photodetector after reflection, interference occurs. With this structure, the optical thickness of the lens being tested can be measured.

[0009] As an improvement, the first light source is a monochromatic LED light source, and a spectrum width is greater than 10nm and less than 50nm.

[0010] As an improvement, the diameter of the light-transmitting hole is less than 0.5 mm, and the distance between the light-transmitting hole and the first light source is less than 0.5 mm.

[0011] As an improvement, the Hartmann aperture is provided with light-transmitting holes arranged in an array, the diameter of the light-transmitting circular holes is 0.2-0.3mm, the center distance of the circular holes is 0.5-0.6mm, the number of circular holes is not less than 7*7, the center position is the reflection area, and the emissivity is 80-90%.

[0012] As an improvement, the second light source module includes a third light source and a second perforated plate, and the second perforated plate is provided with a light-transmitting hole near the light-emitting surface of the third light source; the light emitted by the third light source is emitted after passing through the light-transmitting hole.

[0013] Another technical problem to be solved by the present invention is to provide a testing method for a lens refractive index measuring device, which has the advantages of simple operation, fast detection and high measurement accuracy.

[0014] Another technical solution of the present invention is to provide a testing method for a lens refractive index measuring device, comprising the following steps: S1, before placing the lens to be tested, recording the distribution of the light beam of the first light source on the first photodetector, and recording the signal position x0 of the upper surface of the Hartmann aperture plate in the confocal reflection measurement module; S2, placing the lens to be tested between the first beam splitter and the Hartmann aperture plate, adjusting the position of the lens to be tested until the first photodetector detects that the center of the lens to be tested coincides with the center of the light path of the first light source; calculating the refractive power of the lens to be tested according to the light intensity distribution in the first photodetector; S3, turning off the first light source and turning on the second light source, moving the moving component at a uniform speed, and the lens group and the second port move synchronously at a uniform speed, and the second photodetector records the confocal signal position x1 on the upper surface of the Hartmann aperture plate, and the confocal reflection positions x2 and x3 of the upper and lower surfaces of the lens to be tested; S4, calculating the refractive index n of the lens according to x0, x1, x2, x3 and the refractive power of the lens.

[0015] After adopting the above structure, the lens refractive index measurement method of the present invention has the following advantages compared with the prior art:

[0016] Since the lens refractive index measuring method of the present invention can easily and quickly measure the five values ​​of x0, x1, x2, x3 and the refractive power of the lens being measured, the lens refractive index n can be calculated based on x0, x1, x2, x3 and the refractive power of the lens, there is no need to destroy the lens, the operation is simple, the detection is fast, and it is suitable for the refractive index measurement of ordinary lenses, aspherical lenses, cylindrical lenses and other irregular surface lenses.

[0017] Another technical problem to be solved by the present invention is to provide a testing method for a lens refractive index measuring device, which has the advantages of simple operation, fast detection and high measurement accuracy.

[0018] Another technical solution of the present invention is to provide a testing method for a lens refractive index measuring device, comprising the following steps: S1, before placing the lens to be tested, recording the distribution of the light beam of the first light source on the first photodetector, and recording the position x0 of the reflector when interference occurs in the second photodetector; S2, placing the lens to be tested between the first beam splitter and the Hartmann aperture plate, adjusting the position of the lens to be tested until the first photodetector detects that the center of the lens to be tested coincides with the center of the light path of the first light source; calculating the refractive power of the lens to be tested based on the light intensity distribution in the first photodetector; S3, turning off the first light source and turning on the second light source, moving the moving component at a uniform speed, the reflector, the lens group and the second port move synchronously at a uniform speed, the second photodetector records the interference position x1 of the lens to be tested, and the third photodetector records the confocal reflection positions x2 and x3 of the upper and lower surfaces of the lens to be tested; S4, calculating the refractive index n of the lens based on x0, x1, x2, x3 and the refractive power of the lens.

[0019] After adopting the above structure, the lens refractive index measurement method of the present invention has the following advantages compared with the prior art:

[0020] Since the lens refractive index measuring method of the present invention can easily and quickly measure the five values ​​of x0, x1, x2, x3 and the refractive power of the lens being measured, the lens refractive index n can be calculated based on x0, x1, x2, x3 and the refractive power of the lens, there is no need to destroy the lens, the operation is simple, the detection is fast, and it is suitable for the refractive index measurement of ordinary lenses, aspherical lenses, cylindrical lenses and other irregular surface lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the first embodiment of the lens refractive index measuring device of the present invention.

[0022] Figure 2 It is a schematic structural diagram of the second embodiment of the lens refractive index measuring device of the present invention.

[0023] As shown in the figure: 1. the first light source module, 2. the first collimating lens, 3. the Hartmann aperture, 4. the first photodetector, 5. the second light source, 6. the second photodetector, 7. the Y-type optical fiber, 701. the first port, 702. the second port, 703. the third port, 8. the lens group, 9. the first beam splitter, 10. the moving component, 12. the lens to be measured, 13. the second light source module, 14. the second collimating lens, 15. the focusing lens, 16. the second beam splitter, 17. the third beam splitter, 18. the reflector, 19. the third photodetector. DETAILED DESCRIPTION

[0024] In order to better understand the present application, a more detailed description of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numerals refer to the same elements.

[0025] It should be noted that in this specification, the expressions first, second, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Therefore, without departing from the teaching of this application, the first beam splitter discussed below may also be referred to as the second beam splitter.

[0026] In the drawings, the thickness, size and shape of objects have been slightly exaggerated for ease of explanation. The drawings are only examples and are not drawn strictly to scale.

[0027] It should also be understood that the terms "comprises", "includes", "has", "includes", "comprising", when used in this specification, indicate the presence of the described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof. In addition, when a statement such as "at least one of" appears after a list of listed features, it modifies the entire listed features rather than modifying the individual elements in the list.

[0028] Embodiment 1

[0029] The lens refractive index measuring device of the present invention comprises a diopter measuring module, a confocal reflection measuring module and a measured lens.

[0030] The diopter measurement module includes a first light source module 1, a first collimating lens 2, a Hartmann aperture plate 3 and a first photodetector 4. The first light source module 1 includes a first light source and a first aperture plate, and a light-transmitting hole is provided on a side of the first aperture plate close to the light-emitting surface of the first light source; the light emitted by the first light source is emitted after passing through the light-transmitting hole. The first light source is a monochromatic LED light source, and the spectrum width is greater than 10 nanometers and less than 50 nanometers. The diameter of the light-transmitting hole is less than 0.5 mm, preferably less than 0.2 mm; the distance between the light-transmitting hole and the first light source is less than 0.5 mm; the focal length of the first collimating lens 2 is greater than 50 mm, and preferably, the focal length of the first collimating lens 2 is greater than 100 mm. The first light source is arranged at the back focus of the first collimating lens 2. The Hartmann aperture plate 3 is provided with light-transmitting holes arranged in an array, that is, a metal film is plated on one side of the surface of the Hartmann aperture plate 3, and the metal film is provided with an array of light-transmitting circular holes. The diameter of the light-transmitting circular hole is 0.2-0.3 mm, the center distance of the circular hole is 0.5-0.6 mm, and the number of circular holes is not less than 7*7. The first photodetector 4 is a CCD or CMOS sensor with a resolution greater than 320*240 pixels, preferably greater than 640*480 pixels.

[0031] The light emitted by the first light source module 1 becomes a parallel light beam after passing through the first collimating lens 2 ; the parallel light beam passes through the measured lens 12 and the Hartmann aperture plate 3 and then enters the first photodetector 4 .

[0032] The confocal reflection measurement module includes a second light source 5, a second photodetector 6, a Y-type optical fiber 7, a lens group 8 and a first beam splitter 9; the Y-type optical fiber 7 has three ports. The second port 702 of the Y-type optical fiber 7 is located at the rear focus of the lens group 8. The second port 702 and the lens group 8 are both installed on a moving component 10, and the moving component 10 can drive the second port 702 and the lens group 8 to move back and forth. The second light source 5 is an LED light source or a laser light source, and the central wavelength of the first light source is the same as the central wavelength of the second light source 5.

[0033] The light emitted by the second light source 5 is coupled into the Y-type optical fiber 7 by the first port 701 of the Y-type optical fiber 7, and is emitted from the second port 702 of the Y-type optical fiber 7. The light beam emitted from the second port 702 is converged by the lens group 8; the first beam splitter 9 is arranged between the first collimating lens 2 and the lens 12 to be measured, and the converged light is then reflected by the first beam splitter 9 and focused at the lens 12 to be measured; the moving component 10 moves back and forth, and the light beam can be focused on the upper surface of the Hartmann aperture plate 3 and the upper and lower surfaces of the lens 12 to be measured (that is, the upper surface is the surface where the light enters, and the lower surface is the surface where the light exits). When focusing, the reflected light will return to the second port 702 along the original path, and after propagation through the optical fiber, it will be emitted from the third port 703 of the Y-type optical fiber 7 to the second photodetector 6. The light guiding relationship of the light path of the Y-type optical fiber is that the light is conducted between the first port and the second port, and between the second port and the third port.

[0034] The present invention also discloses a testing method for the above-mentioned lens refractive index measuring device, comprising the following steps:

[0035] S1, before placing the lens 12 to be tested, record the distribution of the light beam of the first light source on the first photodetector 4, and record the signal position x0 of the upper surface of the Hartmann aperture plate 3 (i.e., the surface close to the lens to be tested) in the confocal reflection measurement module;

[0036] S2, placing the lens 12 to be tested between the first beam splitter 9 and the Hartmann aperture plate 3, adjusting the position of the lens 12 to be tested until the first photodetector 4 detects that the center of the lens 12 to be tested coincides with the center of the optical path of the first light source; calculating the diopter Φ of the lens to be tested according to the light intensity distribution in the first photodetector 4;

[0037] S3, turn off the first light source, turn on the second light source 5, move the moving assembly 10 at a constant speed, the lens group 8 and the second port 702 move synchronously at a constant speed, and the second photodetector 6 records the confocal signal position x1 on the upper surface of the Hartmann aperture plate 3, and the confocal reflection positions x2 and x3 on the upper and lower surfaces of the measured lens 12;

[0038] S4. Calculate the lens refractive index n according to x0, x1, x2, x3 and the lens diopter Φ. The specific calculation formula is as follows:

[0039]

[0040]

[0041]

[0042]

[0043] Embodiment 2

[0044] The lens refractive index measuring device of the present invention comprises a diopter measuring module, a confocal reflection measuring module, an optical thickness measuring module and a measured lens.

[0045] The diopter measurement module includes a first light source module 1, a first collimating lens 2, a Hartmann aperture plate 3 and a first photodetector 4. The first light source module 1 includes a first light source and a first aperture plate, and a light-transmitting hole is provided on a side of the first aperture plate close to the light-emitting surface of the first light source; the light emitted by the first light source is emitted after passing through the light-transmitting hole. The first light source is a monochromatic LED light source, and the spectrum width is greater than 10 nanometers and less than 50 nanometers. The diameter of the light-transmitting hole is less than 0.5 mm, preferably less than 0.2 mm; the distance between the light-transmitting hole and the first light source is less than 0.5 mm; the focal length of the first collimating lens 2 is greater than 50 mm, and preferably, the focal length of the first collimating lens 2 is greater than 100 mm. The first light source is arranged at the back focus of the first collimating lens 2. The Hartmann aperture plate 3 is provided with light-transmitting holes arranged in an array, that is, a metal film is plated on one side of the surface of the Hartmann aperture plate 3, and the metal film is provided with an array of light-transmitting circular holes. The diameter of the light-transmitting circular hole is 0.2-0.3 mm, the center distance of the circular hole is 0.5-0.6 mm, and the number of circular holes is not less than 7*7. The first photodetector 4 is a CCD or CMOS sensor with a resolution greater than 320*240 pixels, preferably greater than 640*480 pixels.

[0046] The light emitted by the first light source module 1 becomes a parallel light beam after passing through the first collimating lens 2 ; the parallel light beam passes through the measured lens 12 and the Hartmann aperture plate 3 and then enters the first photodetector 4 .

[0047] The confocal reflection measurement module includes a second light source 5, a second photodetector 6, a Y-type optical fiber 7, a lens group 8 and a first beam splitter 9; the Y-type optical fiber 7 has three ports. The second port 702 of the Y-type optical fiber 7 is located at the rear focus of the lens group 8. The second port 702 and the lens group 8 are both installed on a moving component 10, and the moving component 10 can drive the second port 702 and the lens group 8 to move back and forth. The second light source 5 is an LED light source or a laser light source, and the central wavelength of the first light source is the same as the central wavelength of the second light source 5.

[0048] The light emitted by the second light source 5 is coupled into the Y-type optical fiber 7 by the first port 701 of the Y-type optical fiber 7, and is emitted from the second port 702 of the Y-type optical fiber 7. The light beam emitted from the second port 702 is converged by the lens group 8; the first beam splitter 9 is arranged between the first collimating lens 2 and the measured lens 12, and the converged light is then reflected by the first beam splitter 9 and focused at the measured lens 12; the moving component 10 moves back and forth, and the light beam can be focused on the upper surface of the Hartmann aperture plate 3 and the upper and lower surfaces of the measured lens 12 (that is, the upper surface is the surface where the light enters, and the lower surface is the surface where the light exits). When focusing, the reflected light will return to the second port 702 along the original path, and after propagation through the optical fiber, it will be emitted from the third port 703 of the Y-type optical fiber 7 to the second photodetector 6.

[0049] The optical thickness measurement module includes a second light source module 13, a second collimating lens 14, a focusing lens 15, a second beam splitter 16, a third beam splitter 17, a reflector 18 and a third photodetector 19; the second light source module 13 includes a third light source and a second aperture plate, the third light source is a monochromatic LED light source, the wavelength is the same as the wavelength of the first light source, and the spectrum width is greater than 10 nanometers and less than 50 nanometers. The second aperture plate is provided with a light-transmitting hole close to the light-emitting surface of the third light source, the diameter of the light-transmitting hole is less than 0.2 mm, preferably less than 0.1 mm, and the distance between the light-transmitting hole and the third light source is less than 0.5 mm; the focal length of the second collimating lens 14 is greater than 50 mm, preferably greater than 100 mm, and the third light source is placed at the rear focus of the second collimating lens 14. The focal length of the focusing lens 15 is placed between the second collimating lens 14 and the second beam splitter 16, and the focal length is greater than 50 mm, preferably greater than 100 mm. The second beam splitter 16 is a semi-transparent and semi-reflective mirror, and the ratio of transmittance to reflectance is in the range of 3:7-7:3; the third beam splitter 17 is a semi-transparent and semi-reflective mirror, and the ratio of transmittance to reflectance is 5:5.

[0050] The light emitted by the second light source module 13 becomes a parallel light beam after passing through the second collimating lens 14, and is irradiated onto the second beam splitter 16 through the focusing lens 15; after being reflected by the second beam splitter 16, it enters the main light path; then it passes through the third beam splitter 17 and is divided into two beams of light, one of which is reflected onto the reflector 18, and then reflected back by the reflector 18 along the original path, and part of the light is transmitted through the third beam splitter 17 and enters the third photodetector 19; the other beam of light is transmitted through the third beam splitter 17, and is reflected along the original path by the upper surface of the Hartmann aperture plate 3, and the reflected light is reflected through the third beam splitter 17 and enters the third photodetector 19; when the two parts of light reflected and transmitted by the third beam splitter 17 are reflected and then enter the third photodetector 19 at the same time; the reflector 18 is installed on the moving component 10, and the moving reflector 18, when the two parts of light reflected and transmitted by the third beam splitter 17 enter the third photodetector 19 after reflection, interference occurs.

[0051] The present invention also discloses a testing method for the above-mentioned lens refractive index measuring device, comprising the following steps:

[0052] S1, before placing the lens 12 to be tested, record the distribution of the light beam of the first light source on the first photodetector 4, and record the position x0 of the reflector 18 when interference occurs in the second photodetector 4;

[0053] S2, placing the lens 12 to be tested between the first beam splitter 9 and the Hartmann aperture plate 3, adjusting the position of the lens 12 to be tested until the first photodetector 4 detects that the center of the lens 12 to be tested coincides with the center of the optical path of the first light source; calculating the diopter Φ of the lens 12 to be tested according to the light intensity distribution in the first photodetector 4;

[0054] S3, turn off the first light source, turn on the second light source 5, move the moving assembly 10 at a constant speed, the reflector 18, the lens group 8 and the second port 702 move synchronously at a constant speed, the second photodetector 6 records the interference position x1 of the measured lens 12, and the third photodetector 19 records the confocal reflection positions x2 and x3 of the upper and lower surfaces of the measured lens 12;

[0055] S4. Calculate the lens refractive index n according to x0, x1, x2, x3 and the lens diopter Φ. The specific calculation formula is as follows:

[0056]

[0057]

[0058] Compared with the first specific embodiment, the measurement accuracy of the refractive index of the lens in this specific embodiment is higher.

Claims

1. A lens refractive index measuring device, characterized in that: It includes a diopter measurement module, a confocal reflection measurement module and a lens to be measured; The diopter measurement module comprises a first light source module, a first collimating lens, a Hartmann aperture and a first photodetector; the light emitted by the first light source module becomes a parallel light beam after passing through the first collimating lens; The parallel light beam passes through the measured lens and the Hartmann aperture and then enters the first photoelectric detector; The confocal reflection measurement module comprises a second light source, a second photodetector, a Y-type optical fiber, a lens group and a first beam splitter; the light emitted by the second light source is coupled into the Y-type optical fiber by the first port of the Y-type optical fiber and emitted from the second port of the Y-type optical fiber, the second port is placed at the back focus of the lens group, and the light beam emitted from the second port is converged by the lens group; the first beam splitter is arranged between the first collimating lens and the measured lens, and the converged light is then reflected by the first beam splitter and focused at the measured lens; the second port and the lens group are both installed on a moving component, the moving component moves back and forth along the optical axis direction, and the light beam is focused on the upper surface of the Hartmann aperture plate and the upper and lower surfaces of the measured lens respectively. When focusing, the reflected light returns to the second port along the original path, propagates through the Y-type optical fiber, and is emitted from the third port of the Y-type optical fiber to the second photodetector; The measuring device also includes an optical thickness measuring module; the optical thickness measuring module includes a second light source module, a second collimating lens, a focusing lens, a second beam splitter, a third beam splitter, a reflector and a third photodetector; the light emitted by the second light source module becomes a parallel light beam after passing through the second collimating lens, and the parallel light beam is irradiated on the second beam splitter after passing through the focusing lens; it enters the main light path after being reflected by the second beam splitter; it is then divided into two beams of light after passing through the third beam splitter, one of which is reflected on the reflector, and then reflected back by the reflector along the original path, and part of the light is transmitted through the third beam splitter and enters the third photodetector; the other beam of light is transmitted through the third beam splitter and reflected along the original path by the upper surface of the Hartmann aperture plate, and the reflected light is reflected through the third beam splitter and enters the third photodetector; when the two parts of light reflected and transmitted by the third beam splitter are reflected and then enter the third photodetector at the same time; the reflector is installed on the moving component and moves synchronously with the second port and the lens group, and the moving reflector, when the two parts of light reflected and transmitted by the third beam splitter enter the third photodetector after reflection and the optical path is equal, interference occurs; The testing method based on the lens refractive index measuring device includes the following steps: S1. Before placing the lens to be tested, record the distribution of the light beam of the first light source module on the first photodetector, and record the signal position x0 of the upper surface of the Hartmann aperture in the confocal reflection measurement module; S2, placing the lens to be tested between the first beam splitter and the Hartmann aperture, adjusting the position of the lens to be tested until the first photoelectric detector detects that the center of the lens to be tested coincides with the center of the optical path of the first light source module; calculating the diopter of the lens to be tested according to the light intensity distribution in the first photoelectric detector; S3, turn off the first light source module, turn on the second light source, move the moving assembly at a constant speed, and the lens group and the second port move synchronously at a constant speed, and the second photodetector records the confocal signal position x1 on the upper surface of the Hartmann aperture piece, and the confocal reflection positions x2 and x3 on the upper and lower surfaces of the measured lens; S4. Calculate the refractive index n of the lens according to x0, x1, x2, x3 and the refractive power of the lens.

2. The lens refractive index measuring device according to claim 1, characterized in that: The first light source module comprises a first light source and a first hole plate. A light-transmitting hole is provided on a side of the first hole plate close to the light-emitting surface of the first light source. The light emitted by the first light source is emitted after passing through the light-transmitting hole.

3. The lens refractive index measuring device according to claim 2, characterized in that: The first light source is a monochromatic LED light source, and the spectrum width is greater than 10nm and less than 50nm.

4. The lens refractive index measuring device according to claim 2, characterized in that: The diameter of the light-transmitting hole is less than 0.5 mm, and the distance between the light-transmitting hole and the first light source is less than 0.5 mm.

5. The lens refractive index measuring device according to claim 1, characterized in that: The focal length of the first collimating lens is greater than 50 mm.

6. The lens refractive index measuring device according to claim 1, characterized in that: The Hartmann aperture sheet is provided with light-transmitting circular holes arranged in an array, the diameter of the light-transmitting circular holes is 0.2-0.3mm, the center distance of the circular holes is 0.5-0.6mm, the number of the circular holes is not less than 7*7, the center position is the reflection area, and the emissivity is 80-90%.

7. The lens refractive index measuring device according to claim 1, characterized in that: The second light source module comprises a third light source and a second perforated plate. The second perforated plate is provided with a light-transmitting hole near the light-emitting surface of the third light source. The light emitted by the third light source is emitted after passing through the light-transmitting hole.

8. A lens refractive index measuring device, characterized in that: It includes a diopter measurement module, a confocal reflection measurement module and a lens to be measured; The diopter measurement module comprises a first light source module, a first collimating lens, a Hartmann aperture and a first photodetector; the light emitted by the first light source module becomes a parallel light beam after passing through the first collimating lens; The parallel light beam passes through the measured lens and the Hartmann aperture and then enters the first photoelectric detector; The confocal reflection measurement module comprises a second light source, a second photodetector, a Y-type optical fiber, a lens group and a first beam splitter; the light emitted by the second light source is coupled into the Y-type optical fiber by the first port of the Y-type optical fiber and emitted from the second port of the Y-type optical fiber, the second port is placed at the back focus of the lens group, and the light beam emitted from the second port is converged by the lens group; the first beam splitter is arranged between the first collimating lens and the measured lens, and the converged light is then reflected by the first beam splitter and focused at the measured lens; the second port and the lens group are both installed on a moving component, the moving component moves back and forth along the optical axis direction, and the light beam is focused on the upper surface of the Hartmann aperture plate and the upper and lower surfaces of the measured lens respectively. When focusing, the reflected light returns to the second port along the original path, propagates through the Y-type optical fiber, and is emitted from the third port of the Y-type optical fiber to the second photodetector; The measuring device also includes an optical thickness measuring module; the optical thickness measuring module includes a second light source module, a second collimating lens, a focusing lens, a second beam splitter, a third beam splitter, a reflector and a third photodetector; the light emitted by the second light source module becomes a parallel light beam after passing through the second collimating lens, and the parallel light beam is irradiated on the second beam splitter after passing through the focusing lens; it enters the main light path after being reflected by the second beam splitter; it is then divided into two beams of light after passing through the third beam splitter, one of which is reflected on the reflector, and then reflected back by the reflector along the original path, and part of the light is transmitted through the third beam splitter and enters the third photodetector; the other beam of light is transmitted through the third beam splitter and reflected along the original path by the upper surface of the Hartmann aperture plate, and the reflected light is reflected through the third beam splitter and enters the third photodetector; when the two parts of light reflected and transmitted by the third beam splitter are reflected and then enter the third photodetector at the same time; the reflector is installed on the moving component and moves synchronously with the second port and the lens group, and the moving reflector, when the two parts of light reflected and transmitted by the third beam splitter enter the third photodetector after reflection and the optical path is equal, interference occurs; The testing method based on the lens refractive index measuring device includes the following steps: S1. Before placing the lens to be tested, record the distribution of the light beam of the first light source module on the first photodetector, and record the position x0 of the reflector when interference occurs in the second photodetector; S2, placing the lens to be tested between the first beam splitter and the Hartmann aperture, adjusting the position of the lens to be tested until the first photoelectric detector detects that the center of the lens to be tested coincides with the center of the optical path of the first light source module; calculating the diopter of the lens to be tested according to the light intensity distribution in the first photoelectric detector; S3, turn off the first light source module, turn on the second light source, move the moving assembly at a constant speed, the reflector, the lens group and the second port move synchronously at a constant speed, the second photodetector records the interference position x1 of the measured lens, and the third photodetector records the confocal reflection positions x2 and x3 of the upper and lower surfaces of the measured lens; S4. Calculate the refractive index n of the lens according to x0, x1, x2, x3 and the refractive power of the lens.

Images