CN217845590U - Objective lens aberration testing device - Google Patents
Objective lens aberration testing device Download PDFInfo
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- CN217845590U CN217845590U CN202222314373.9U CN202222314373U CN217845590U CN 217845590 U CN217845590 U CN 217845590U CN 202222314373 U CN202222314373 U CN 202222314373U CN 217845590 U CN217845590 U CN 217845590U
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- 230000004075 alteration Effects 0.000 title claims abstract description 41
- 238000012360 testing method Methods 0.000 title claims abstract description 18
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- 238000009434 installation Methods 0.000 claims abstract description 3
- 230000010287 polarization Effects 0.000 claims description 7
- 230000001915 proofreading effect Effects 0.000 abstract description 2
- 238000004445 quantitative analysis Methods 0.000 abstract description 2
- 238000003384 imaging method Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 7
- 230000003287 optical effect Effects 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000012937 correction Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000006059 cover glass Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 238000013441 quality evaluation Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
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Abstract
The utility model provides an objective aberration testing arrangement, its error is little, can preserve the image and carry out quantitative analysis, can improve precision and the efficiency of proofreading and correct the objective aberration. The device comprises a light source, a convergent lens, a star point pinhole, a beam splitter prism, a collimating lens, a mounting seat for mounting an objective lens to be measured or a flat crystal and a spherical reflector which are sequentially arranged; the side part of the beam splitter prism is provided with a CCD, a star point pinhole is positioned at the focal plane of the convergent lens and the collimating lens, and the center of the spherical reflector is positioned at the focal plane of the objective lens to be measured; light rays emitted by the light source are converged to a star point pinhole through the converging lens, then form parallel light to be emitted through the beam splitter prism and the collimating lens, the parallel light is converged and imaged through the objective lens to be tested installed on the installation seat, then enters the spherical reflector, is reflected by the objective lens to be tested, the collimating lens and the beam splitter prism, and is imaged on the CCD.
Description
Technical Field
The utility model relates to an objective aberration detects technical field, based on star point imaging principle evaluation objective aberration and rectifies.
Background
In the field of applied optics, the evaluation of the imaging quality of an optical system is a relatively important issue. In many conventional image quality evaluation methods, the star point method is a relatively common method.
The star point method is a method for simply and conveniently detecting the aberration of a microscope objective, and qualitatively evaluating the quality of imaging by observing the shape and light intensity distribution of diffraction images (generally called star point images) formed on an image surface and different sections in front of and behind the image surface by a point light source after passing through an optical system.
The traditional star point inspection device generally has two structures: the first is that the imaging of the illuminated star point particles is directly observed by an optical system consisting of an objective lens to be detected and a visual system, the structure is convenient and simple, but the image cannot be stored, the objectivity of qualitative judgment of the imaging is poor, and the requirement on the size of the star point particles is high particularly when a high-power objective lens is detected; the second is that after the objective lens to be detected is aligned with the approximately infinite beam emitted by the straight lens to be imaged, the objective lens to be detected is observed by a microscope system, and the accuracy of the detection result is influenced by the installation and adjustment error and the error of the microscope system.
Disclosure of Invention
The utility model aims at providing an objective aberration testing arrangement, it requires to hang down, system error is little, CCD camera device replaces people's eye observation, can preserve the image and carry out quantitative analysis, can improve precision and the efficiency of proofreading and correct the objective aberration to the pinhole component.
The utility model discloses an objective aberration testing device, which comprises a light source, a convergent lens, a star point pinhole, a beam splitter prism, a collimating lens, a mounting seat for mounting an objective to be tested or a flat crystal and a spherical reflector which are arranged in sequence; the side part of the beam splitter prism is provided with a CCD, a star point pinhole is positioned at the focal plane of the convergent lens and the collimating lens, and the center of the spherical reflector is positioned at the focal plane of the objective lens to be measured; light rays emitted by the light source are converged to a star point pinhole through the converging lens, then form parallel light emergent through the beam splitter prism and the collimating lens, the parallel light is converged and imaged through the objective lens to be tested arranged on the mounting seat, then enters the spherical reflector, is reflected by the objective lens to be tested, the collimating lens and the beam splitter prism, and is imaged on the CCD.
According to the objective lens aberration testing device, the mounting seat is arranged on the adjusting device capable of driving the mounting seat to swing, and the mounting seat is provided with the mounting seat reference surface for positioning the objective lens or the flat crystal to be tested.
In the objective lens aberration testing device, the light source, the convergent lens, the star point pinhole, the beam splitter prism and the collimating lens are all arranged on one lens cone, and a lens cone reference surface for positioning the flat crystal is arranged on the end surface of the lens cone opposite to the mounting seat; the lens barrel reference surface is parallel to the mounting seat reference surface.
In the objective aberration testing device, the beam splitter prism is a polarization beam splitter prism; a lambda/4 wave plate is arranged between the collimating lens and the mounting seat.
In the objective aberration testing device, the converging lens is an aspheric converging lens.
In the objective lens aberration testing device, the light source is a monochromatic laser light source.
The utility model has the advantages that:
light beams of a light source such as a laser light source are focused on a star point pinhole through a converging lens such as an aspheric lens, and the star point pinhole is positioned on a focal plane of a collimating lens, so that an infinite star point is formed after passing through the collimating lens, an objective lens to be tested images the infinite star point, the infinite star point is secondarily reflected through a spherical reflector, passes through the objective lens to be tested, and finally is imaged on a CCD after sequentially passing through the collimating lens and a PBS light splitting prism.
The laser is selected to replace the traditional xenon lamp as the light source of the system: the monochromaticity can reduce the influence of chromatic aberration, the high collimation can meet the requirement of a point light source imaging system, and the high brightness can ensure the brightness of a diffraction ring. According to different use requirements, the laser light sources with different wavelengths can be replaced.
An aspheric lens is selected as a condenser lens to focus the laser beam on a star pinhole: the aspheric lens can maintain good aberration correction, can correct spherical aberration brought by a focusing system, and can focus a laser beam into a better point light source.
And (3) placing a star point pinhole at the position of a focal plane of the collimating lens, wherein the focal length of the collimating lens is longer, so that the requirement on the aperture of the star point is lowered, and the size of the pinhole is not more than the radius R of a diffraction image corresponding to the aperture of the effective star point light beam. Compared with the traditional transmission structure which adopts the illuminated star point particles as point light sources, the requirement on the star point particles is higher, and particularly when a high-power lens is inspected, the processing difficulty and the cost of the star point particles are high, the size of the star point particles needs to be matched with the numerical aperture NA of an objective lens to be detected, and a cover glass needs to be added on the star point particle plate to meet the detection condition; the star point pinhole used in the structure has low cost and small processing difficulty and can meet the detection requirements of most of objective lenses.
A spherical reflector is arranged behind an objective lens to be measured, and the traditional structure is replaced by directly observing the image by using a microscope system. If a microscope system is selected for observing and imaging, errors of the microscope observation system can be introduced, so that the judgment of an inspector on results is influenced, and the microscope objective also has NA and multiplying power requirements for different objective lenses to be detected; the spherical reflector with the surface shape precision reaching lambda/20 is used, so that the system structure is simplified, the system error is reduced, the imaging of an infinite star point of the objective lens to be detected is reflected back to the objective lens to be detected, the aberration of the objective lens to be detected is amplified in the final imaging, the qualitative judgment of the aberration of the objective lens to be detected by inspectors is facilitated, and the subsequent aberration correction is more convenient.
Because the laser beam is linearly polarized light, the system uses a PBS beam splitter prism (polarization beam splitter prism) and a lambda/4 wave plate combined beam splitter, the polarization state of the imaging beam can be changed by rotating the wave plate, and the imaging brightness can be changed along with the polarization state.
The CCD is used for acquiring star point images, and image point graphs are displayed on the display, so that a plurality of people can observe and image simultaneously; the related images can be saved, and the image analysis can be carried out by a computer, so that the aberration of the objective lens can be quantitatively evaluated. With the development of CCD and computer technologies, digitization of optical images has become a necessary trend. The star point images are collected by a computer, so that the fatigue observed by human eyes can be reduced, the star point images before focus, focus plane and focus can be reproduced simultaneously, and the nature and the size of aberration can be judged.
Drawings
FIG. 1 is a schematic view of the optical principle of an objective aberration testing device;
FIG. 2 is a schematic view of a star point reflection;
FIG. 3 is a schematic operation diagram corresponding to step S2;
fig. 4 is a schematic operation diagram corresponding to step S7.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The objective lens aberration testing device comprises a laser light source 1, an aspheric convergent lens 2, a star point pinhole 3, a polarization beam splitter prism 4, a collimating lens 5, a lambda/4 wave plate 6, a mounting seat for mounting an objective lens 8 or a flat crystal 7 to be tested and a spherical reflector 9 which are sequentially arranged; the CCD 10 is provided at the side of the beam splitter prism. The mounting seat is arranged on an adjusting device capable of driving the mounting seat to swing, and a mounting seat reference surface for positioning an objective lens or a flat crystal to be measured is arranged on the mounting seat. The laser source 1, the aspheric convergent lens 2, the star point pinhole 3, the polarization beam splitter prism 4, the collimating lens 5, the lambda/4 wave plate 6 and the CCD 10 are all arranged on a lens barrel 11 (which can also be regarded as a collimating lens barrel) together, and a lens barrel reference surface 12 for positioning the flat crystal is arranged on the end surface of the lens barrel opposite to the mounting base; the barrel reference surface 12 is parallel to the mount reference surface 13.
The utility model provides a method of timing objective aberration based on star point inspection principle, specific operating procedure explains as follows:
s1: a flat crystal, an aberration correction tool, and a data recording table were prepared.
S2: correcting an optical axis: as shown in fig. 3, the flat crystal is firstly abutted against the lens barrel reference surface of the collimating lens barrel, a star point image appears on the display screen, and the position of the star point image is marked; and then placing the flat crystal on the reference surface of the mounting seat of the objective lens to be detected, adjusting the mounting seat through the tilting mechanism to find a star point image and adjusting the star point image to the marked star point image position.
S3: finding a star point reflection image of the objective lens to be detected: and installing the objective lens to be detected, adjusting the axial distance between the objective lens to be detected and the spherical reflector and adjusting the performance parameters of the camera through the Z-axis coarse and fine movement structure according to the focal length of the objective lens to be detected and the curved surface R value of the spherical reflector, and shooting and storing the best star point reflection image after finding the best star point reflection image.
S4: judging the on-axis aberration of the objective lens: if the objective lens is a conventional objective lens, according to the pattern of the star point image, inspectors qualitatively judge the aberration condition of the objective lens to be detected. If the objective lens to be measured has higher aberration requirements, PSF analysis can be carried out on the shot star point image, and the acquired star point image is compared with an ideal PSF.
S5: correcting aberration of the objective lens to be detected: and if the aberration of the objective lens to be detected does not meet the qualified requirement, adopting a corresponding aberration correction method.
S6: and re-detecting the objective lens to be detected.
S7: as shown in fig. 4, if the off-axis aberration of the objective lens to be tested needs to be tested, the lens barrel in fig. 4 is integrally rotated by a certain angle by taking the diaphragm center 14 of the objective lens to be tested as a rotation point, the star point image is found by adjusting the position of the spherical reflector in the direction perpendicular to the optical axis of the objective lens to be tested through the X-Y displacement platform, and the tester performs aberration judgment.
S8: and numbering and recording the objective lens, and storing related images and data.
Claims (6)
1. An objective lens aberration testing device is characterized in that: the device comprises a light source, a convergent lens, a star point pinhole, a beam splitter prism, a collimating lens, a mounting seat for mounting an objective lens to be measured or a flat crystal and a spherical reflector which are arranged in sequence; the side part of the beam splitting prism is provided with a CCD, a star point pinhole is positioned at the focal plane of the convergent lens and the collimating lens, and the center of the spherical reflector is positioned at the focal plane of the objective lens to be measured; light rays emitted by the light source are converged to a star point pinhole through the converging lens, then form parallel light to be emitted through the beam splitter prism and the collimating lens, the parallel light is converged and imaged through the objective lens to be tested installed on the installation seat, then enters the spherical reflector, is reflected by the objective lens to be tested, the collimating lens and the beam splitter prism, and is imaged on the CCD.
2. The aberration testing apparatus for an objective lens according to claim 1, wherein: the mounting seat is arranged on an adjusting device capable of driving the mounting seat to swing, and a mounting seat reference surface for positioning an objective lens or a flat crystal to be measured is arranged on the mounting seat.
3. The aberration testing apparatus for an objective lens according to claim 2, wherein: the light source, the convergent lens, the star point pinhole, the beam splitter prism and the collimating lens are all arranged on a lens barrel together, and a lens barrel reference surface for positioning the flat crystal is arranged on the end surface of the lens barrel opposite to the mounting seat; the lens barrel reference surface is parallel to the mounting seat reference surface.
4. The aberration testing apparatus of an objective lens according to claim 1, wherein: the beam splitter prism is a polarization beam splitter prism; a lambda/4 wave plate is arranged between the collimating lens and the mounting seat.
5. The aberration testing apparatus for an objective lens according to claim 1, wherein: the converging lens is an aspheric converging lens.
6. The aberration testing apparatus of an objective lens according to claim 1, wherein: the light source is a monochromatic laser light source.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222314373.9U CN217845590U (en) | 2022-09-01 | 2022-09-01 | Objective lens aberration testing device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202222314373.9U CN217845590U (en) | 2022-09-01 | 2022-09-01 | Objective lens aberration testing device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115420471A (en) * | 2022-09-01 | 2022-12-02 | 南京东利来光电实业有限责任公司 | Objective lens aberration testing method based on star point method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115420471A (en) * | 2022-09-01 | 2022-12-02 | 南京东利来光电实业有限责任公司 | Objective lens aberration testing method based on star point method |
| CN115420471B (en) * | 2022-09-01 | 2024-08-20 | 南京东利来光电实业有限责任公司 | Object lens aberration testing method based on star point method |
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