Reflection-type large-aperture eccentric meter

Abstract

The embodiment of the invention relates to the technical field of reflective eccentric meters, in particular to a reflective large-diameter eccentric meter. The reflection-type large-aperture eccentric instrument comprises a light source, a lighting lens group, a cross reticle, a semi-reflecting and semi-transmitting prism, a collimating lens group, a first spherical reflector and a second spherical reflector which are sequentially arranged along the direction of an optical main axis, the concave surface of the first spherical reflector faces the convex surface of the second spherical reflector, and the first spherical reflector is provided with a central through hole allowing emergent parallel light of the collimating lens group to pass through; the convex surface of the second spherical reflector reflects the emergent parallel light of the collimating lens group for the first time to obtain primary reflected light, the concave surface of the first spherical reflector reflects the primary reflected light for the second time to obtain secondary reflected light, and the secondary reflected light can be converged on the optical main axis to obtain a light convergence point. The reflection-type large-caliber eccentric meter provided by the embodiment of the specification can be used for carrying out eccentric detection on a detected lens with a large-caliber central hole.

Description

Technical Field

[0001] The present invention relates to the technical field of reflective eccentricity meters, and particularly to a reflective large-aperture eccentricity meter. Background Art

[0002] A reflective eccentricity meter is a commonly used instrument for measuring the eccentricity of lenses or other optical elements. Eccentricity refers to the non-coincidence of the geometric central axis of an optical element with its optical principal axis. The working principle of eccentricity detection is as follows: Light is irradiated onto the measured surface of the measured lens, and then the reflection of the measured surface on the light is observed to determine whether the measured lens is eccentric. However, some measured lenses have central holes. When the aperture of the central hole is relatively large (for example, greater than or equal to 30 mm), the existing reflective eccentricity meters in the prior art can no longer perform eccentricity detection on the measured lenses because the light generated by the reflective eccentricity meter will all pass through the central hole of the measured lens, and it cannot form a reflection on the measured surface of the measured lens. Summary of the Invention

[0003] In view of the problems existing in the prior art, the present invention provides a reflective large-aperture eccentricity meter that can perform eccentricity detection on a measured lens with a large-aperture central hole.

[0004] The present invention is achieved through the following technical solutions: A reflective large-aperture eccentricity meter includes a light source, an illumination lens group, a cross reticle, a semi-reflective and semi-transmissive prism, a collimating lens group, a first spherical mirror, and a second spherical mirror that are sequentially arranged along the optical principal axis direction; The concave surface of the first spherical mirror faces the convex surface of the second spherical mirror, and the first spherical mirror is provided with a central through hole that allows the parallel light emitted by the collimating lens group to pass through; The convex surface of the second spherical mirror reflects the parallel light emitted by the collimating lens group for the first time to obtain a primary reflected light, and the concave surface of the first spherical mirror reflects the primary reflected light for the second time to obtain a secondary reflected light. The secondary reflected light can converge on the optical principal axis to obtain a light convergence point; When the measured lens is arranged between the second spherical mirror and the light convergence point, the center of curvature of the measured surface of the measured lens coincides with the light convergence point, and at least part of the secondary reflected light can irradiate the measured surface of the measured lens.

[0005] Preferably, the concave surface curvature radius of the first spherical mirror is a * 200 mm, the concave surface aperture diameter is a * 80 mm, the convex surface curvature radius of the second spherical mirror is a * 30 mm, the convex surface aperture diameter is a * 30 mm, and the initial distance between the first spherical mirror and the second spherical mirror is a * 100 mm, where a is a multiple value.

[0006] Preferably, the concave curvature radius of the first spherical mirror is 200 mm, the concave aperture diameter is 80 mm, the convex curvature radius of the second spherical mirror is 30 mm, the convex aperture diameter is 30 mm, and the initial distance between the first spherical mirror and the second spherical mirror is 100 mm.

[0007] Preferably, the distance between the first spherical mirror and the second spherical mirror is adjustable, and the adjustable range of the distance is 85 - 105 mm.

[0008] Preferably, the second spherical mirror is arranged on a sliding guide rail.

[0009] Preferably, the illumination lens group includes a plano-convex lens one, a plano-convex lens two, a plano-convex lens three, and a plano-convex lens four arranged in sequence along the optical axis direction. The convex surface of the plano-convex lens one faces and is closely attached to the convex surface of the plano-convex lens two, and the convex surface of the plano-convex lens three faces and is closely attached to the convex surface of the plano-convex lens four.

[0010] Preferably, the collimating lens group includes a first sub-lens group and a second sub-lens group; the first sub-lens group includes a meniscus lens one and a plano-concave lens arranged in sequence along the optical axis direction; the second sub-lens group includes a meniscus lens two and a bi-convex lens arranged in sequence along the optical axis direction.

[0011] Preferably, the reflective large-aperture eccentricity measurer further includes a beam splitter arranged in cooperation with the semi-reflective semi-transmissive prism, and a scale reticle, an imaging lens group, and a charge-coupled device arranged in cooperation with the beam splitter.

[0012] Preferably, the imaging lens group includes a first bi-convex lens, a bi-concave lens, and a second bi-convex lens arranged in sequence along the optical axis direction.

[0013] Preferably, the reflective large-aperture eccentricity measurer further includes an eyepiece arranged in cooperation with the beam splitter.

[0014] In summary, the present invention has the following beneficial effects: The reflective large-aperture eccentricity measurer of the present invention is provided with a first spherical mirror and a second spherical mirror. The convex surface of the second spherical mirror can reflect the outgoing parallel light of the collimating lens group for the first time to obtain a primary reflected light. The concave surface of the first spherical mirror can reflect the primary reflected light for the second time to obtain a secondary reflected light. The secondary reflected light can converge on the optical main axis to obtain a light convergence point. When the center of the curvature radius of the measured surface of the measured lens coincides with the light convergence point, even if the measured lens has a center hole with a large aperture, there will still be part of the secondary reflected light irradiating on the measured surface of the measured lens, so that the reflective large-aperture eccentricity measurer can perform eccentricity detection on the measured lens with a large-aperture center hole.

[0015] Further or more detailed beneficial effects will be described in combination with specific embodiments in the specific implementation manners. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a reflective large-aperture eccentricity measurer according to the present invention; Figure 2 is Figure 1 a schematic structural diagram of the reflective large-aperture eccentricity measurer after installing the lens to be measured in Figure 3 is Figure 2 a partially enlarged view of the reflective large-aperture eccentricity measurer in Figure 4 is Figure 3 a partially enlarged view of the reflective large-aperture eccentricity measurer in Figure 5 is Figure 3 another partially enlarged view of the reflective large-aperture eccentricity measurer in SPECIFIC IMPLEMENTATION MANNERS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings.

[0018] This specific embodiment is only an interpretation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0019] As Figures 1 to 3 shown, this embodiment discloses a reflective large-aperture eccentricity measurer, which includes a light source 1, an illumination lens group 2, a cross reticle 3, a semi-transmissive and semi-reflective prism 4, a collimating lens group, a first spherical mirror 7 and a second spherical mirror 8 arranged in sequence along the optical axis direction.

[0020] The concave surface of the first spherical mirror 7 faces the convex surface of the second spherical mirror 8, and the first spherical mirror 7 is provided with a central through hole allowing the outgoing parallel light of the collimating lens group to pass through.

[0021] The convex surface of the second spherical mirror 8 reflects the outgoing parallel light of the collimating lens group for the first time to obtain a primary reflected light, and the concave surface of the first spherical mirror 7 reflects the primary reflected light for the second time to obtain a secondary reflected light, and the secondary reflected light can converge on the optical axis to obtain a light convergence point S.

[0022] When the lens 9 to be measured is arranged between the second spherical mirror 8 and the light convergence point S, the center of the curvature radius of the measured surface of the lens 9 to be measured coincides with the light convergence point S, and at least part of the secondary reflected light can irradiate the measured surface of the lens 9 to be measured.

[0023] In this embodiment, the light source 1 is an LED white light lamp. The cross reticle 3 is disposed at the exit pupil position of the illumination lens group 2 and at the focus of the collimating lens group, so that the light generated by the light source 1 becomes a parallel beam of light after passing through the illumination lens group 2, the cross reticle 3, the semi-reflective semi-transmissive prism 4, and the collimating lens group. The parallel light emitted from the collimating lens group passes through the central through hole of the first spherical mirror 7 and then irradiates the convex surface of the second spherical mirror 8. The clear aperture of the central through hole of the first spherical mirror 7 can be 10 mm. If the clear aperture is too large, the aberration will also become larger, which will affect the overall imaging effect.

[0024] The convex surface of the second spherical mirror 8 reflects the parallel light emitted from the collimating lens group to the concave surface of the first spherical mirror 7. The second spherical mirror 8 has the function of diffusing the light to a specific aperture. The concave surface of the first spherical mirror 7 reflects the light reflected by the second spherical mirror 8 again. The first spherical mirror 7 has the function of converging the light. In short, the first spherical mirror 7 and the second spherical mirror 8 are cooperatively arranged to achieve a converging light effect with a relatively large aperture. That is, when the center of the curvature radius of the measured surface of the measured lens 9 coincides with the light converging point S, even if the measured lens 9 has a central hole with a relatively large aperture, part of the reflected light of the first spherical mirror 7 will still irradiate the measured surface of the measured lens 9, so that the eccentricity measurer of this embodiment can perform eccentricity detection on the measured lens with a relatively large aperture central hole.

[0025] Further, in this embodiment, the concave surface curvature radius of the first spherical mirror 7 is a * 200 mm, the concave surface aperture diameter is a * 80 mm, the convex surface curvature radius of the second spherical mirror 8 is a * 30 mm, the convex surface aperture diameter is a * 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is a * 100 mm, where a is a multiple value. a can be any value such as 0.5, 1, 2, etc.

[0026] When a is equal to 1, the concave surface curvature radius of the first spherical mirror 7 is 200 mm, the concave surface aperture diameter is 80 mm, the convex surface curvature radius of the second spherical mirror 8 is 30 mm, the convex surface aperture diameter is 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm. At this time, the overall focal length of the first spherical mirror 7 and the second spherical mirror 8 is 100 mm, and the overall working distance (i.e., the distance from the second spherical mirror 8 to the light converging point S) is 620 mm.

[0027] When the radius of curvature of the measured surface of the measured lens 9 is 600 mm, the measured lens 9 can be arranged between the second spherical mirror 8 and the light convergence point S, and there is still a distance of 20 mm between the measured lens 9 and the second spherical mirror 8. At this time, the maximum aperture that can be measured is 60 mm. Then, as long as the aperture of the central hole of the measured lens 9 is less than 60 mm, the eccentricity measurer of this embodiment can perform eccentricity detection on it. That is, when the concave curvature radius of the first spherical mirror 7 is 200 mm, the concave aperture diameter is 80 mm, the convex curvature radius of the second spherical mirror 8 is 30 mm, the convex aperture diameter is 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm, if the radius of curvature of the measured surface of the measured lens 9 is 600 mm, then even if the aperture of the central hole of the measured lens 9 is relatively large (greater than or equal to 30 mm), the eccentricity measurer of this embodiment can still perform eccentricity detection on it.

[0028] When the radius of curvature of the measured surface of the measured lens 9 is 610 mm, the measured lens 9 can be arranged between the second spherical mirror 8 and the light convergence point S, and there is still a distance of 10 mm between the measured lens 9 and the second spherical mirror 8. At this time, the maximum aperture that can be measured is still 60 mm. Then, as long as the aperture of the central hole of the measured lens 9 is less than 60 mm, the eccentricity measurer of this embodiment can perform eccentricity detection on it. That is, when the concave curvature radius of the first spherical mirror 7 is 200 mm, the concave aperture diameter is 80 mm, the convex curvature radius of the second spherical mirror 8 is 30 mm, the convex aperture diameter is 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm, if the radius of curvature of the measured surface of the measured lens 9 is 610 mm, then even if the aperture of the central hole of the measured lens 9 is relatively large (greater than or equal to 30 mm), the eccentricity measurer of this embodiment can still perform eccentricity detection on it.

[0029] When the radius of curvature of the measured surface of the measured lens 9 is 300 mm, the measured lens 9 can be set between the second spherical mirror 8 and the light convergence point S, and the measured lens 9 and the second spherical mirror 8 still have a distance of 320 mm. At this time, the maximum aperture that can be measured is 30 mm. Then, as long as the aperture of the central hole of the measured lens 9 is less than 30 mm, the eccentricity measurer of this embodiment can perform eccentricity detection on it. That is, when the concave curvature radius of the first spherical mirror 7 is 200 mm, the concave aperture diameter is 80 mm, the convex curvature radius of the second spherical mirror 8 is 30 mm, the convex aperture diameter is 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm, if the radius of curvature of the measured surface of the measured lens 9 is 300 mm, then even if the aperture of the central hole of the measured lens 9 is relatively large (for example, slightly less than 30 mm), the eccentricity measurer of this embodiment can still perform eccentricity detection on it.

[0030] Theoretically, as long as the measured lens 9 with a relatively large central hole can be placed between the second spherical mirror 8 and the light convergence point S (of course, the center of the radius of curvature of the measured surface of the measured lens 9 needs to coincide with the light convergence point S), and then at least part of the reflected light of the first spherical mirror 7 can irradiate the measured surface of the second spherical mirror 8, then regardless of the values of the concave curvature radius and concave aperture diameter of the first spherical mirror 7, the convex curvature radius and convex aperture diameter of the second spherical mirror 8, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8, the eccentricity measurer of this embodiment can perform eccentricity detection on the measured lens 9 with a relatively large central hole.

[0031] However, considering factors such as the operation difficulty of eccentricity detection and the production cost of the eccentricity measurer, in this embodiment, the concave curvature radius and concave aperture diameter of the first spherical mirror 7, the convex curvature radius and convex aperture diameter of the second spherical mirror 8, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 can be set to relatively optimal fixed values. For example, the concave curvature radius of the first spherical mirror 7 is 200 mm, the concave aperture diameter is 80 mm, the convex curvature radius of the second spherical mirror 8 is 30 mm, the convex aperture diameter is 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm. At this time, as long as the radius of curvature of the measured surface of the measured lens 9 is greater than or equal to 300 mm and less than 620 mm, then even if the central hole of the measured lens 9 is relatively large, the eccentricity measurer of this embodiment can perform eccentricity detection on it.

[0032] Furthermore, the distance between the first spherical mirror 7 and the second spherical mirror 8 is adjustable, and the adjustable range of the distance is 85 - 105 mm. Among them, the second spherical mirror 8 is arranged on the sliding guide rail, making it more convenient for the second spherical mirror 8 to move and adjust.

[0033] In this embodiment, the installation position of the second spherical mirror 8 can be moved along the optical axis direction, so that the distance between the first spherical mirror 7 and the second spherical mirror 8 can be changed. The initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm. The second spherical mirror 8 can be moved leftward along the optical axis (in Figure 1 the perspective view), so that the minimum distance between the first spherical mirror 7 and the second spherical mirror 8 is 85 mm; the second spherical mirror 8 can also be moved rightward along the optical axis (in Figure 1 the perspective view), so that the maximum distance between the first spherical mirror 7 and the second spherical mirror 8 is 105 mm.

[0034] When the distance between the first spherical mirror 7 and the second spherical mirror 8 is 85 mm, the overall focal length of the first spherical mirror 7 and the second spherical mirror 8 is infinite, the overall working distance can reach 10000 mm, and the secondary reflected light generated by the first spherical mirror 7 is parallel to the optical axis direction. Although the secondary reflected light cannot converge on the optical axis to obtain a light convergence point S at this time, that is, the eccentricity measurer cannot be used for eccentricity detection of the measured lens 9 with a large-diameter central hole, the eccentricity measurer can be used to measure the parallelism of a lens with a flat measured surface. If the distance between the first spherical mirror 7 and the second spherical mirror 8 is less than 85 mm, the secondary reflected light will diverge and cannot converge, making the eccentricity measurer unable to be used normally.

[0035] When the distance between the first spherical mirror 7 and the second spherical mirror 8 is 105 mm, the overall focal length of the first spherical mirror 7 and the second spherical mirror 8 is 75 mm, and the overall working distance is 500 mm. If the distance between the first spherical mirror 7 and the second spherical mirror 8 is greater than 105 mm, the secondary reflected light will converge on the second spherical mirror 8, which will also cause the eccentricity measurer to be unable to be used normally.

[0036] If the radius of curvature of the measured surface of the measured lens 9 is not within the range of greater than or equal to 300 mm and less than 620 mm, for example, when the radius of curvature of the measured surface of the measured lens 9 is 700 mm, then the installation position of the second spherical mirror 8 can be moved so that the distance between the first spherical mirror 7 and the second spherical mirror 8 becomes smaller from 100 mm, and further the overall working distance (i.e., the distance from the second spherical mirror 8 to the light convergence point S) becomes larger from 620 mm. As long as the overall working distance is greater than the radius of curvature of the measured surface of the measured lens 9, for example, the overall working distance can be adjusted to 705 mm. At this time, the measured lens 9 can be placed between the second spherical mirror 8 and the light convergence point S, and the center of the radius of curvature of the measured surface of the measured lens 9 can coincide with the light convergence point S. And at this time, the maximum measurable aperture of the eccentricity measurer is 60 mm.

[0037] If the radius of curvature of the measured surface of the measured lens 9 is equal to 300 mm, but the diameter of the central hole of the measured lens 9 is greater than or equal to 30 mm, then the installation position of the second spherical mirror 8 can be moved so that the distance between the first spherical mirror 7 and the second spherical mirror 8 increases from 100 mm, and further the overall working distance (i.e., the distance from the second spherical mirror 8 to the light convergence point S) decreases from 620 mm. As long as the overall working distance is greater than the radius of curvature of the measured surface of the measured lens 9, for example, the overall working distance can be adjusted to 550 mm. At this time, the measured lens 9 can be placed between the second spherical mirror 8 and the light convergence point S, and the center of the radius of curvature of the measured surface of the measured lens 9 can coincide with the light convergence point S. And at this time, the maximum measurable aperture of the centering instrument is greater than 30 mm.

[0038] If the radius of curvature of the measured surface of the measured lens 9 is slightly less than 300 mm, the installation position of the second spherical mirror 8 can also be moved so that the distance between the first spherical mirror 7 and the second spherical mirror 8 increases from 100 mm.

[0039] In summary, in this embodiment, on the premise that the concave surface radius of curvature of the first spherical mirror 7 is 200 mm, the concave surface aperture diameter is 80 mm, the convex surface radius of curvature of the second spherical mirror 8 is 30 mm, the convex surface aperture diameter is 30 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 100 mm, the second spherical mirror 8 is set to be movable. This setting enables the distance between the first spherical mirror 7 and the second spherical mirror 8 to be adjusted within the range of 85 - 105 mm, and further enables more models of measured lenses 9 to be used by the centering instrument of this embodiment for eccentricity detection, ultimately improving the adaptability of the centering instrument of this embodiment.

[0040] In addition, if the radius of curvature of the measured surface of the measured lens 9 is relatively small or large, and when the centering instrument with a equal to 1 can no longer perform eccentricity detection well, then it is necessary to replace the first spherical mirror 7 and the second spherical mirror 8 of other models with other values of a. For example, when the radius of curvature of the measured surface of the measured lens 9 is 1200 mm, then a can take the value of 2. At this time, the concave surface radius of curvature of the first spherical mirror 7 is 400 mm, the concave surface aperture diameter is 160 mm, the convex surface radius of curvature of the second spherical mirror 8 is 60 mm, the convex surface aperture diameter is 60 mm, and the initial distance between the first spherical mirror 7 and the second spherical mirror 8 is 200 mm.

[0041] Further, as Figure 4As shown, the illumination lens group 2 in this embodiment includes a plano-convex lens 2-1, a plano-convex lens 2-2, a plano-convex lens 2-3, and a plano-convex lens 2-4 arranged in sequence along the optical axis direction. The convex surface of the plano-convex lens 2-1 faces and is closely attached to the convex surface of the plano-convex lens 2-2, and the convex surface of the plano-convex lens 2-3 faces and is closely attached to the convex surface of the plano-convex lens 2-4.

[0042] The illumination lens group 2 with this structure can improve the uniformity of the light rays of the light source 1.

[0043] Furthermore, as Figure 5 shown, the collimating lens group in this embodiment includes a first sub-lens group 5 and a second sub-lens group 6; the first sub-lens group 5 includes a meniscus lens 5-1 and a plano-concave lens 5-2 arranged in sequence along the optical axis direction; the second sub-lens group 6 includes a meniscus lens 6-1 and a biconvex lens 6-2 arranged in sequence along the optical axis direction.

[0044] The first sub-lens group 5 uses two lenses separated in the middle. Among them, the concave surface of the meniscus lens 5-1 faces to the right (in the Figure 5 viewing angle), and the concave surface of the plano-concave lens 5-2 faces to the left (in the Figure 5 viewing angle). Since the curvature radii of the meniscus lens 5-1 and the plano-concave lens 5-2 differ greatly, the first sub-lens group 5 with this structure can improve the overall resolution of the first sub-lens group 5 and at the same time reduce the generation of ghost images (when light passes through one or more lenses, part of the light may be reflected on the front and back surfaces of the lens. These reflected lights may be reflected again through the surfaces of other lenses and finally form images on the imaging surface as well. Such unexpected images caused by internal reflections are usually darker than the original image and are different in position from the original image, and they are called ghost images).

[0045] The second sub-lens group 6 is a cemented lens group, and the aperture diameter of the second sub-lens group 6 is 32 mm.

[0046] Furthermore, the reflective large-aperture eccentricity measurer in this embodiment further includes a beam splitter 10 cooperatively arranged with the semi-reflective semi-transmissive prism 4, a ruled graticule 12, an imaging lens group 13, a charge-coupled device 14 cooperatively arranged with the beam splitter 10, and an eyepiece 11 cooperatively arranged with the beam splitter 10.

[0047] The specific eccentricity detection principle is: When the lens under test 9 is not set, after the cross image on the cross reticle 3 is illuminated by the light source 1 and the illumination lens group 2, a cross image can be formed at the light convergence point S. When the lens under test 9 is set, the cross image is reflected by the surface under test of the lens under test 9, and then the cross image returns along the original light path to the half-reflecting and half-transmitting prism 4 (that is, first reflected to the concave surface of the first spherical mirror 7, then reflected to the convex surface of the second spherical mirror 8, then reversely passes through the central through hole of the first spherical mirror 7, and finally returns to the half-reflecting and half-transmitting prism 4 through the collimating lens group), and then the cross image is reflected by the half-reflecting and half-transmitting prism 4 to the beam splitter 10. The beam splitter 10 divides the cross image into two groups. One group of images is formed on the eyepiece 11 for visual observation by the naked eye; the other group of images is formed on the graduated reticle 12 (there are graduations on the graduated reticle, similar to a ruler, and the interval between each graduation is 0.1 mm, so that the moving distance of the cross image can be read from the graduated ruler). If there is no eccentricity, the moving distance of the cross image is 0. The imaging lens group 13 can image the graduated reticle 12 and the cross image simultaneously onto the charge-coupled device 14 (i.e., the objective lens) for further observation.

[0048] In this embodiment, the imaging lens group 13 includes a first biconvex lens 13-1, a biconcave lens 13-2, and a second biconvex lens 13-3 arranged in sequence along the optical axis direction, and there is a certain distance between the first biconvex lens 13-1 and the biconcave lens 13-2, and there is a certain distance between the biconcave lens 13-2 and the second biconvex lens 13-3. The imaging lens group 13 with this structure can achieve the effect of high-resolution and large-field imaging.

Claims

1. A reflective large-aperture eccentricity measurer, characterized in that, It includes a light source (1), an illumination lens group (2), a cross reticle (3), a semi-transparent and semi-reflective prism (4), a collimating lens group, a first spherical mirror (7) and a second spherical mirror (8) arranged in sequence along the optical axis direction; The concave surface of the first spherical mirror (7) faces the convex surface of the second spherical mirror (8), and the first spherical mirror (7) is provided with a central through hole allowing the outgoing parallel light of the collimating lens group to pass through; The convex surface of the second spherical mirror (8) reflects the outgoing parallel light of the collimating lens group for the first time to obtain a primary reflected light, and the concave surface of the first spherical mirror (7) reflects the primary reflected light for the second time to obtain a secondary reflected light, and the secondary reflected light can converge on the optical axis to obtain a light convergence point (S); When the lens under test (9) is arranged between the second spherical mirror (8) and the light convergence point (S), the center of the curvature radius of the surface under test of the lens under test (9) coincides with the light convergence point (S), and at least part of the secondary reflected light can irradiate the surface under test of the lens under test (9).

2. The reflective large-aperture eccentricity measuring instrument according to claim 1, wherein The concave surface curvature radius of the first spherical mirror (7) is a * 200 mm, the concave surface aperture diameter is a * 80 mm, the convex surface curvature radius of the second spherical mirror (8) is a * 30 mm, the convex surface aperture diameter is a * 30 mm, and the initial distance between the first spherical mirror (7) and the second spherical mirror (8) is a * 100 mm, where a is a multiple value.

3. The reflective large-aperture eccentricity measurer according to claim 2, wherein, The concave surface curvature radius of the first spherical mirror (7) is 200 mm, the concave surface aperture diameter is 80 mm, the convex surface curvature radius of the second spherical mirror (8) is 30 mm, the convex surface aperture diameter is 30 mm, and the initial distance between the first spherical mirror (7) and the second spherical mirror (8) is 100 mm.

4. The reflective large-aperture eccentricity measurer according to claim 3, characterized in that, The distance between the first spherical mirror (7) and the second spherical mirror (8) is adjustable, and the adjustable range of the distance is 85 - 105 mm.

5. The reflective large-aperture eccentricity measurer according to claim 4, wherein The second spherical mirror (8) is arranged on a sliding guide rail.

6. The reflective large-aperture eccentricity measurer according to claim 1, wherein The illumination lens group (2) includes a plano-convex lens one (2-1), a plano-convex lens two (2-2), a plano-convex lens three (2-3) and a plano-convex lens four (2-4) arranged in sequence along the optical axis direction. The convex surface of the plano-convex lens one (2-1) faces and is closely attached to the convex surface of the plano-convex lens two (2-2), and the convex surface of the plano-convex lens three (2-3) faces and is closely attached to the convex surface of the plano-convex lens four (2-4).

7. The reflective large-aperture eccentricity measuring instrument according to claim 1, wherein The collimating lens group includes a first sub-lens group (5) and a second sub-lens group (6); the first sub-lens group (5) includes a meniscus lens one (5-1) and a plano-concave lens (5-2) arranged in sequence along the optical axis direction; the second sub-lens group (6) includes a meniscus lens two (6-1) and a bi-convex lens (6-2) arranged in sequence along the optical axis direction.

8. The reflective large-aperture eccentricity measuring instrument according to claim 1, wherein The reflective large-aperture eccentricity measurer further includes a beam splitter (10) disposed in cooperation with the semi-reflective and semi-transmissive prism (4), and a ruled graticule (12), an imaging lens group (13) and a charge coupled device (14) disposed in cooperation with the beam splitter (10).

9. The reflective large-aperture eccentricity measuring instrument according to claim 8, characterized in that, The imaging lens group (13) includes a first double convex lens (13-1), a double concave lens (13-2) and a second double convex lens (13-3) sequentially arranged along the optical axis direction.

10. The reflective large-aperture eccentricity measurer according to claim 8, wherein, The reflective large-aperture eccentricity measurer further includes an eyepiece (11) disposed in cooperation with the beam splitter (10).

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