Lens mounting flange distance and decentration integrated measuring light path and measuring method

Abstract

The invention discloses a lens mounting flange distance and decentration integrated measurement light path and a measurement method, belongs to the technical field of optical measurement, and aims to solve the problems in the prior art. According to the invention, monochromatic light emitted by a light source passes through a dodging sheet and an emergent small hole sheet and then is collimated into parallel light by a collimation off-axis parabolic mirror, the parallel light is reflected to a rear beam splitter prism by a front beam splitter prism, and the parallel light passes through the rear beam splitter prism and is propagated to a convergent lens; the convergent focus of the convergent lens reaches a to-be-tested system and is collimated again through the convergent lens after being reflected by the to-be-tested system, the collimated light after being collimated is transmitted in two paths, one path of collimated light passes through the rear beam splitter prism and the front beam splitter prism and is transmitted to the energy convergence off-axis parabolic mirror, and the other path of collimated light passes through the energy convergence off-axis parabolic mirror; after being converged by the energy convergence off-axis parabolic mirror, the light enters an optical power detector through an incident small hole sheet; and the other path of collimated light is reflected to the imaging convergence off-axis parabolic mirror by the rear beam splitter prism, and is converged in the area array CCD camera for imaging through the imaging convergence off-axis parabolic mirror.

Description

Technical Field

[0001] The invention belongs to the technical field of optical measurement, and in particular relates to an integrated measurement optical path and a measurement method for lens mounting flange distance and center offset. Background Art

[0002] Transmissive optical systems are generally composed of multiple coaxial lenses. When designing the optical-mechanical structure, it is difficult to perform precise optical-mechanical assembly by using spacers to separate the lenses to ensure the lens spacing. After installation and adjustment, due to the eccentricity of each lens and the spacing error between adjacent lenses, it is difficult to adjust the transmissive system to the expected design indicators. Figure 1 At present, centering adjustment is an important adjustment method that can ensure the adjustment accuracy of the transmission optical system. The principle is: design a lens seat for each lens, first match and repair the center line of the two spherical surfaces of the lens (that is, the optical axis of the lens) and the axis of the outer cylindrical surface of the lens seat (the center deviation of a single lens component) until they coincide, then perform precision turning on the outer cylindrical surface of the lens seat to ensure the matching tolerance of the inner cylindrical surface of the lens barrel, and then correct the distance between the end face of the lens seat and the two spherical vertices of the lens (lens mounting flange distance) to the theoretical value. Each lens and the lens seat form an independent lens assembly; each lens assembly is trimmed according to the above process and then installed into the lens barrel in turn, and finally fixed by a pressing ring to complete the assembly of the transmission optical system.

[0003] It can be seen from the principle of centering assembly that the accurate measurement of the lens mounting flange distance and the lens eccentricity is the key to the correct docking of different lens assemblies. If the center deviation of the lens is too large, the coaxiality of the lens group will be destroyed. The deviation of the lens mounting flange distance will directly affect the air gap between adjacent lenses. The above errors will cause the optical performance of the entire system to be reduced. The center deviation error is generally measured using a center deviation measuring instrument (also called a centering instrument), which uses the principle of parallel light imaging through a lens, with a crosshair as an indicator image, and by rotating the measured lens, observing the radius of the center of the circle formed by the crosshair moving track on the imaging plane to judge the center deviation error of the lens. The Chinese patent with publication number CN107339955B discloses a high-precision lens center deviation detection instrument and a measurement method thereof, and the Chinese patent with publication number CN219349282U discloses a device for adjusting an optical lens by a center deviation measuring instrument. Both center deviation detection devices use a crosshair as an indicator image, and by rotating the measured lens, observing the crosshair moving track on the imaging plane and then judging its center deviation error.

[0004] The air gap between lenses can be measured by interference method. With short coherent laser as light source, the lens center thickness and lens air gap can be measured based on the Michelson interferometer principle. The optical mirror interval measuring device disclosed in the Chinese patent with publication number CN103322933A uses short coherent light as light source, and the light source is connected through optical fiber. Based on the Michelson interferometer principle, the lens to be measured is moved, and the distance of lens movement is judged by observing the change of coherent image on the photodetector, thereby obtaining the air gap between lenses.

[0005] At present, almost all center deviation measuring instruments use the crosshairs as the object point to generate parallel light, and then measure the center deviation through the measuring objective lens. Since the center deviation measuring instrument is only equipped with an area array CCD to receive the return image of the crosshairs, it can only use the size of the fitting circle formed by the trajectory of the crosshairs to determine the eccentricity of the lens or lens group, but cannot obtain the air gap between the lenses, and cannot be used to measure the mounting flange distance of each single lens component in the centering and adjustment process.

[0006] The center spacing measuring instrument that uses short coherence laser as the light source and measures the center thickness of the lens and the air spacing based on the principle of Michelson interferometer can generally only measure the spacing between optical components. When the short coherence laser convergence point to be measured is a non-specular diffuse reflection surface (such as the end face of the lens holder), its return light is difficult to interfere with the measurement optical path, so the installation flange distance cannot be measured; and the short coherence laser light source is relatively expensive, and the optical path is mostly built or designed with customized optical fiber, and the equipment cost is relatively high.

[0007] It can be seen that the center deviation measuring instrument is often used to detect the eccentricity error of the transmission optical system that has been installed and adjusted, and the center interval measuring instrument is often used to detect the distance difference between optical parts; the two detection devices use different optical detection systems. Therefore, when measuring the center deviation (the deviation between the lens optical axis and the center line of the outer circle of the lens seat) of the same lens assembly and the lens interval after multiple lens assemblies are installed, the lens assembly needs to be measured on different devices. If the measurement result does not meet the requirements, the mechanical part size needs to be corrected again, and then the above process is repeated to complete the installation. Repeated installation and measurement of different equipment may lead to measurement errors, and repeated process flows will also increase the installation time. In addition, neither of the above two devices can measure the installation flange distance.

[0008] For the measurement of flange distance, the flange distance can be measured by using a large-range micrometer clamped in a tool to measure the height difference between the center vertex of the lens and the end face of the lens seat. However, this method will cause obvious scratches near the vertex of the lens due to the contact between the measuring ball head of the micrometer and the vertex of the lens, which seriously affects the surface quality of the lens. In addition, it is difficult to ensure that the measuring vertex of the micrometer coincides with the vertex of the lens during measurement. When the radius of curvature of the measured lens is small, the error will be very significant. Summary of the invention

[0009] The purpose of the present invention is to propose an integrated measurement optical path and measurement method for lens mounting flange distance and center offset, so as to solve the problems existing in the prior art that the center offset and flange distance cannot be measured simultaneously, the measurement accuracy is low and the measurement process is difficult.

[0010] The system to be tested targeted by the present invention comprises a lens to be tested which is mounted on a lens holder to be tested.

[0011] To achieve the above-mentioned purpose, the lens mounting flange distance and center offset integrated measurement optical path of the present invention comprises a light source, uniform light, an exit pinhole plate, a collimating off-axis parabolic mirror, a front beam splitter prism, a rear beam splitter prism, a converging lens, an imaging converging off-axis parabolic mirror, a surface array CCD camera, an energy converging off-axis parabolic mirror, an incident pinhole plate, and an optical power detector;

[0012] The monochromatic light emitted by the light source forms a circular light-emitting hole through the light homogenizer and the exit pinhole plate. The light emitted through the exit pinhole plate is collimated into parallel light by the collimating off-axis parabolic mirror, and then reflected to the rear beam splitter prism by the front beam splitter prism. The parallel light then passes through the rear beam splitter prism and propagates to the converging lens.

[0013] The convergence point of the converging lens reaches the system to be measured, and after being reflected by the system to be measured, it is collimated again by the converging lens. The collimated light is propagated in two paths. One path of the collimated light passes through the rear beam splitter prism and the front beam splitter prism to propagate to the energy converging off-axis parabolic mirror, and after being converged by the energy converging off-axis parabolic mirror, it enters the optical power detector through the incident pinhole plate; the other path of the collimated light is reflected by the rear beam splitter prism to the imaging converging off-axis parabolic mirror, and then converged by the imaging converging off-axis parabolic mirror to form an image in the area array CCD camera.

[0014] The light source is a monochromatic LED light source.

[0015] The exit pinhole plate and the incident pinhole plate are conjugate with respect to the working surface of the front beam splitter prism.

[0016] The collimating off-axis parabolic mirror can be replaced by a first lens group. The monochromatic light emitted by the light source passes through the light homogenizer and the exit pinhole plate and is collimated by the first lens group before entering the front beam splitter prism.

[0017] The imaging converging off-axis parabolic mirror can be replaced by a second lens group. The light reflected by the system to be measured and collimated by the converging lens is reflected to the first lens group by the rear beam splitter prism, and is converged by the first lens group to form an image on the area array CCD camera.

[0018] The energy converging off-axis parabolic mirror can be replaced by a third lens group. The light reflected by the system to be measured and collimated by the converging lens passes through the rear beam splitter prism and the front beam splitter prism to the third lens group, and then converged by the third lens group and enters the optical power detector through the incident pinhole.

[0019] The measuring method based on the integrated measuring optical path of lens mounting flange distance and center offset includes a lens mounting flange distance measuring method and a lens center offset measuring method;

[0020] The lens mounting flange distance measurement method comprises the following steps:

[0021] Step 1: preliminarily adjust the system to be tested so that the light passing through the converging lens converges at the vertex of the mirror surface of the lens to be tested, passes through the converging lens again for collimation after being reflected by the lens to be tested, and the collimated light passes through the rear beam splitter prism and the front beam splitter prism to propagate to the energy converging off-axis parabolic mirror, and enters the optical power detector through the incident pinhole after being converged by the energy converging off-axis parabolic mirror, and moves the system to be tested back and forth so that the converging lens focusing point is located at the vertex of the mirror surface of the lens to be tested, the front part of the vertex of the mirror surface of the lens to be tested, and the rear part of the vertex of the mirror surface of the lens to be tested respectively; record the position information of the system to be tested corresponding to the maximum value detected by the optical power detector as the position information of the system to be tested when the converging lens focusing point is located at the vertex of the mirror surface of the lens to be tested;

[0022] Step 2: preliminarily adjust the system to be tested, so that the light passing through the converging lens converges at the end face of the lens seat to be tested, and is collimated again by the converging lens after being reflected by the end face of the lens seat to be tested, and the collimated light passes through the rear beam splitter prism and the front beam splitter prism to propagate to the energy converging off-axis parabolic mirror, and after being converged by the energy converging off-axis parabolic mirror, enters the optical power detector through the incident pinhole sheet, and moves the system to be tested back and forth, so that the converging lens convergence point is respectively located at the end face of the lens seat to be tested, the front of the end face of the lens seat to be tested, and the rear of the end face of the lens seat to be tested; record the position information of the system to be tested corresponding to the maximum value detected by the optical power detector as the position information of the system to be tested when the converging lens convergence point is located at the end face of the lens seat to be tested;

[0023] Step 3: Subtract the position information recorded in step 2 from that in step 1 to obtain the lens mounting flange focal distance of the system to be tested;

[0024] The lens center deviation measurement method is as follows: adjusting the position of the system to be measured or replacing the converging lens so that the light converged by the converging lens converges at the spherical center of the mirror surface of the lens to be measured, the converging light is reflected by the measured surface of the lens to be measured and returns along the original path, the returning light is collimated by the converging lens, and then reflected by the rear beam splitter prism to the imaging converging off-axis parabolic mirror, and is converged by the imaging converging off-axis parabolic mirror to form an image in the area array CCD camera; rotating the lens holder to be measured around the central axis, if the position of the circular spot image in the area array CCD camera remains unchanged, then there is no deviation between the optical axis of the lens to be measured and the center line of the outer circle of the lens holder to be measured; if the circular spot image in the area array CCD camera moves in a circular trajectory, then there is a deviation between the optical axis of the lens to be measured and the center line of the outer circle of the lens holder to be measured, and the center deviation of the system to be measured is obtained according to the diameter of the circular trajectory.

[0025] The specific process of obtaining the center deviation of the system to be measured based on the diameter of the circular trajectory is as follows:

[0026] The circular trajectory diameter D can be obtained by fitting the circular trajectory using a circle fitting algorithm;

[0027] Then, the center deviation θ is obtained according to the formula D = 2βRtan(2θ);

[0028] Where: D is the diameter of the trajectory circle;

[0029] β is the vertical axis magnification of the optical system;

[0030] R is the radius of curvature of the lens to be tested;

[0031] θ is the angle of the center deviation.

[0032] The beneficial effects of the present invention are as follows: the integrated measurement optical path and measurement method of the lens mounting flange distance and center deviation of the present invention introduces a circular light spot as an indicator image, and uses the same optical measurement system to achieve the measurement of the lens mounting flange distance and center deviation. The measurement optical system is simplified, and the circular light spot is used as the object point. Not only can the trajectory circle fitting be performed to determine the center deviation as with the use of a crosshair, but the energy returned by the circular light spot can be detected by the energy detector at the rear through a preset aperture, and the mounting flange distance can be measured by comparing the position difference of the two sides at maximum energy. The measurement optical path can reduce the measurement process of a single lens assembly during centering and adjustment, and the measurement process is all non-contact measurement. Monochrome LEDs or low-cost lasers can be used as light sources, and one optical path can be used to achieve the required measurement data, while ensuring the measurement accuracy, effectively reducing the process difficulty and equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the installation process of the lens assembly on the lens barrel in the prior art;

[0034] Figure 2 It is a schematic diagram of the optical path for integrated measurement of flange distance and center offset of the lens installation of the present invention;

[0035] Figure 3 It is a schematic diagram of light transmission when the convergence point of the light of the integrated measurement light path of the lens installation flange distance and center offset of the present invention is located at the vertex of the lens surface to be measured;

[0036] Figure 4 It is a schematic diagram of light transmission when the convergence point of the light in the integrated measurement light path of the lens installation flange distance and center offset of the present invention is located behind the vertex of the lens surface to be measured;

[0037] Figure 5 It is a schematic diagram of light transmission when the convergence point of the light in the integrated measurement light path of the lens installation flange distance and center offset of the present invention is located in front of the vertex of the lens surface to be measured;

[0038] Figure 6 It is a schematic diagram of light transmission when the convergence point of the light of the integrated measurement light path of the lens installation flange distance and center offset of the present invention is located at the end face of the lens holder to be measured;

[0039] Figure 7 It is a schematic diagram of light transmission when the convergence point of the light in the integrated measurement light path of the lens installation flange distance and center offset of the present invention is located behind the end face of the lens holder to be measured;

[0040] Figure 8 It is a schematic diagram of light transmission when the convergence point of the light of the integrated measurement light path of the lens installation flange distance and center offset of the present invention is located in front of the end face of the lens seat to be measured;

[0041] Fig. 9 It is a schematic diagram of the relationship between the detection energy intensity of the lens installation flange distance and the center offset integrated measurement light path detector and the position of the system to be measured;

[0042] Wherein: 1. light source, 2. light homogenizer, 3. exit pinhole, 4. collimating off-axis parabolic mirror, 5. front beam splitter, 6. rear beam splitter, 7. converging lens, 8. lens holder to be tested, 9. lens to be tested, 10. imaging converging off-axis parabolic mirror, 11. area array CCD camera, 12. energy converging off-axis parabolic mirror, 13. incident pinhole, 14. optical power detector. DETAILED DESCRIPTION

[0043] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0044] The system to be tested targeted by the present invention includes a lens to be tested 9 mounted on a lens holder to be tested 8 .

[0045] See also Figure 2 The lens mounting flange distance and center offset integrated measurement optical path of the present invention comprises a light source 1, a uniform light, an exit pinhole plate 3, a collimating off-axis parabolic mirror 4, a front beam splitter prism 5, a rear beam splitter prism 6, a converging lens 7, an imaging converging off-axis parabolic mirror 10, a surface array CCD camera 11, an energy converging off-axis parabolic mirror 12, an incident pinhole plate 13, and an optical power detector 14;

[0046] The monochromatic light emitted by the light source 1 forms a light-emitting circular hole through the light-homogenizing sheet 2 and the exit pinhole sheet 3, and produces a circular indication image; the light emitted through the exit pinhole sheet 3 is collimated into parallel light by the collimating off-axis parabola 4, and then reflected to the rear beam splitter prism 6 by the front beam splitter prism 5, and the parallel light then passes through the rear beam splitter prism 6 and propagates to the converging lens 7, which plays the role of converging the light;

[0047] When measuring the lens mounting flange distance, the focusing point is the end face of the lens holder 88 to be measured or the mirror vertex of the lens 9 to be measured. After the light is reflected by the end face of the lens holder 8 to be measured or the mirror vertex of the lens 9 to be measured, it passes through the converging lens 7 again for collimation. The collimated light passes through the rear beam splitter prism 6 and the front beam splitter prism 5 to propagate to the energy converging off-axis parabolic mirror 12. After being converged by the energy converging off-axis parabolic mirror 12, it enters the optical power detector 14 through the incident pinhole plate 13. By moving the system to be measured back and forth, the energy passing through the incident pinhole plate 13 can be controlled, thereby affecting the detected energy size.

[0048] When the center of the measuring lens is offset, the light passing through the converging lens 7 will converge on the spherical center of the measured mirror surface of the lens 9 to be measured. At this time, the light will be reflected back to the converging lens 7 by the measured mirror surface along the original path, and will be propagated to the rear dichroic prism 6 after being collimated by the converging lens 7, and will be reflected by the rear dichroic prism 6 to the imaging converging off-axis parabolic mirror 10, and then will be converged by the imaging converging off-axis parabolic mirror 10 to form an image in the area array CCD camera 11; when there is a deviation between the central optical axis of the lens 9 to be measured and the center line of the outer circle of the lens holder 8 to be measured, the system to be measured is rotated, and the circular image in the area array CCD camera 11 will move in a circular trajectory with the rotation of the system to be measured.

[0049] The light source 1 is a monochromatic LED light source 1 .

[0050] The exit pinhole plate 3 and the incident pinhole plate 13 are conjugate with respect to the working surface of the front beam splitter prism 5 .

[0051] The collimating off-axis parabolic mirror 4 can be replaced by a first lens group. The monochromatic light emitted by the light source 1 passes through the light homogenizing plate 2 and the exit pinhole plate 3 and is collimated by the first lens group before entering the front beam splitter prism 5 .

[0052] The imaging converging off-axis parabolic mirror 10 can be replaced by a second lens group. The light reflected by the system to be measured and collimated by the converging lens 7 is reflected to the first lens group by the rear beam splitter prism 6, and is converged by the first lens group to form an image on the area array CCD camera 11.

[0053] The energy converging off-axis parabolic mirror 12 can be replaced by a third lens group. The light reflected by the system to be measured and collimated by the converging lens 7 passes through the rear beam splitter prism 6 and the front beam splitter prism 5 to the third lens group, and then converged by the third lens group and enters the optical power detector 14 through the incident pinhole plate 13.

[0054] The measuring method based on the integrated measuring optical path of lens mounting flange distance and center offset includes a lens mounting flange distance measuring method and a lens center offset measuring method;

[0055] The lens mounting flange distance measurement method comprises the following steps:

[0056] Step 1: See Figure 3-5, preliminarily adjust the system to be tested so that the light passing through the converging lens 7 converges near the vertex of the mirror surface of the lens 9 to be tested, and is collimated again by the converging lens 7 after being reflected by the lens 9 to be tested, and the collimated light passes through the rear beam splitter prism 6 and the front beam splitter prism 5 to propagate to the energy converging off-axis parabolic mirror 12, and after being converged by the energy converging off-axis parabolic mirror 12, it enters the optical power detector 14 through the incident pinhole sheet 13, and moves the system to be tested back and forth so that the converging point of the converging lens 7 is respectively located at the vertex of the mirror surface of the lens 9 to be tested, the front part of the vertex of the mirror surface of the lens 9 to be tested, and the rear part of the vertex of the mirror surface of the lens 9 to be tested; record the position information of the system to be tested corresponding to the maximum value detected by the optical power detector 14; when the light converges at the vertex of the mirror surface of the lens 9 to be tested, the off-axis parabolic mirror 12 is used to detect the position of the light. The mirror converges at the incident pinhole plate 13, and the energy entering the pinhole plate is the largest at this time; when the parallel light passing through the converging lens 7 converges before and after the vertex of the mirror surface of the lens to be measured 9, the light is no longer reflected along the original path, and the reflected light is no longer emitted in parallel after passing through the converging lens 7, but has a small divergence angle. The divergent light passes through the rear beam splitter prism 6 and the front beam splitter prism 5 to propagate to the energy converging off-axis parabolic mirror 12, and passes through the incident pinhole plate 13 after converging; at this time, no matter whether the parallel light passing through the converging lens 7 converges before or after the vertex of the mirror surface of the lens to be measured 9, only a part of the light converged by the energy converging off-axis parabolic mirror 12 will be able to pass through the incident pinhole plate 13 and enter the optical power detector 14, and the energy becomes relatively smaller relative to the convergence and vertex;

[0057] Here, the light rays passing through the converging lens 7 are converged near the vertex of the mirror surface of the lens 9 to be tested, which means that the converging point of the light rays of the converging lens 7 is located at the vertex of the mirror surface of the lens 9 to be tested, or located in front of the vertex of the mirror surface of the lens 9 to be tested, or located behind the vertex of the mirror surface of the lens 9 to be tested, and during the movement, the values ​​detected by the optical power detector 14 include values ​​located at the positions on, in front of, and behind the vertex of the mirror surface of the lens 9 to be tested;

[0058] Step 2: See Figure 6-8 , preliminarily adjust the system to be tested so that the light passing through the converging lens 7 converges near the end face of the lens holder 8 to be tested, and is collimated again by the converging lens 7 after being reflected by the end face of the lens holder 8 to be tested, and the collimated light passes through the rear beam splitter prism 6 and the front beam splitter prism 5 to propagate to the energy converging off-axis parabolic mirror 12, and enters the optical power detector 14 through the incident pinhole sheet 13 after being converged by the energy converging off-axis parabolic mirror 12, and moves the system to be tested back and forth so that the converging point of the converging lens 7 is respectively located at the end face of the lens holder 8 to be tested, the front of the end face of the lens holder 8 to be tested, and the rear of the end face of the lens holder 8 to be tested; record the position information of the system to be tested corresponding to the maximum value detected by the optical power detector 14, that is, the position information of the system to be tested when the converging point of the converging lens 7 is located at the end face of the lens holder 8 to be tested;

[0059] Here, the light rays passing through the converging lens 7 are converged near the end face of the lens holder 8 to be tested, which means that the light convergence point of the converging lens 7 is located on the end face of the lens holder 8 to be tested, in front of the end face of the lens holder 8 to be tested, or in the rear of the end face of the lens holder 8 to be tested, and during the movement, the values ​​detected by the optical power detector 14 include the values ​​located on the upper, front and rear positions of the end face of the lens holder 8 to be tested;

[0060] Step 3: Subtract the position information of the system to be tested recorded in step 2 and step 1 to obtain the lens mounting flange focal distance of the system to be tested; see Fig. 9 , the solid line represents the energy change curve of the lens holder 8 to be tested, the dotted line represents the energy change curve of the lens 9 to be tested, and the position difference L between the peaks of the two curves is the flange distance;

[0061] The lens center deviation measurement method is as follows: adjusting the position of the system to be measured or replacing the converging lens 7 so that the light converged by the converging lens 7 converges at the spherical center of the mirror surface of the lens 9 to be measured, the converging light is reflected by the measured surface of the lens 9 to be measured and returns along the original path, the returning light is collimated by the converging lens 7, and then reflected by the rear beam splitter prism 6 to the imaging converging off-axis parabolic mirror 10, and is converged by the imaging converging off-axis parabolic mirror 10 to form an image in the area array CCD camera 11; rotating the lens holder 8 to be measured around the central axis, if the position of the circular light spot image in the area array CCD camera 11 remains unchanged, then there is no deviation between the optical axis of the lens 9 to be measured and the center line of the outer circle of the lens holder 8 to be measured; if the circular light spot image in the area array CCD camera 11 moves in a circular trajectory, then there is a deviation between the optical axis of the lens 9 to be measured and the center line of the outer circle of the lens holder 8 to be measured, and the center deviation of the system to be measured is obtained according to the diameter of the circular trajectory.

[0062] The specific process of obtaining the center deviation of the system to be measured based on the diameter of the circular trajectory is as follows:

[0063] The center of the circular light spot in the area array CCD camera 11 is extracted using a center positioning algorithm. When the lens 9 to be tested has a center deviation, the lens 9 to be tested is rotated, and the center of the extracted circular light spot moves along a circular trajectory as the lens 9 to be tested rotates. The circular trajectory is fitted using a circle fitting algorithm to obtain the circular trajectory diameter D.

[0064] Then, the center deviation θ is obtained according to the formula D = 2βRtan(2θ);

[0065] Where: D is the diameter of the trajectory circle;

[0066] β is the vertical axis magnification of the optical system;

[0067] R is the radius of curvature of the lens to be tested;

[0068] θ is the angle of the center deviation.

Claims

1. Lens installation flange distance and center offset integrated measurement optical path, characterized in that: It comprises a light source (1), a uniform light, an output pinhole plate (3), a collimating off-axis parabolic mirror (4), a front beam splitter prism (5), a rear beam splitter prism (6), a converging lens (7), an imaging converging off-axis parabolic mirror (10), a surface array CCD camera (11), an energy converging off-axis parabolic mirror (12), an incident pinhole plate (13), and an optical power detector (14); Monochromatic light emitted by a light source (1) passes through a light homogenizing plate (2) and an exit pinhole plate (3) to form a light emitting circular hole. Light emitted from the exit pinhole plate (3) is collimated into parallel light by a collimating off-axis parabolic mirror (4), and then reflected by a front beam splitter prism (5) to a rear beam splitter prism (6). The parallel light then passes through the rear beam splitter prism (6) and propagates to a converging lens (7). The convergence point of the convergent lens (7) is directed to the system to be measured, and after being reflected by the system to be measured, it is collimated again by the convergent lens (7). The collimated light is propagated in two paths. One path of the collimated light passes through the rear beam splitter prism (6) and the front beam splitter prism (5) to propagate to the energy convergence off-axis parabolic mirror (12), and after being converged by the energy convergence off-axis parabolic mirror (12), it enters the optical power detector (14) through the incident pinhole plate (13); the other path of the collimated light is reflected by the rear beam splitter prism (6) to the imaging convergence off-axis parabolic mirror (10), and then converged by the imaging convergence off-axis parabolic mirror (10) to form an image in the area array CCD camera (11).

2. The lens mounting flange distance and center offset integrated measurement optical path according to claim 1, characterized in that: The light source (1) is a monochromatic LED light source (1).

3. The lens mounting flange distance and center offset integrated measurement optical path according to claim 1, characterized in that: The exit pinhole plate (3) and the incident pinhole plate (13) are conjugate with respect to the working surface of the front beam splitter prism (5).

4. The lens mounting flange distance and center offset integrated measurement optical path according to any one of claims 1 to 3, characterized in that: The collimating off-axis parabolic mirror (4) can be replaced by a first lens group. Monochromatic light emitted by the light source (1) passes through a light homogenizing sheet (2) and an exit pinhole sheet (3) and then is collimated by the first lens group and enters a front beam splitter prism (5).

5. The lens mounting flange distance and center offset integrated measurement optical path according to any one of claims 1 to 3, characterized in that: The imaging convergent off-axis parabolic mirror (10) can be replaced by a second lens group. The light rays collimated by the convergent lens (7) after being reflected by the system to be measured are reflected to the first lens group through the rear beam splitter prism (6). After being converged by the first lens group, an image is formed on the area array CCD camera (11).

6. The lens mounting flange distance and center offset integrated measurement optical path according to any one of claims 1 to 3, characterized in that: The energy converging off-axis parabolic mirror (12) can be replaced by a third lens group. The light reflected by the system to be measured and collimated by the converging lens (7) passes through the rear beam splitter prism (6) and the front beam splitter prism (5) to the third lens group, and after being converged by the third lens group, enters the optical power detector (14) through the incident pinhole plate (13).

7. A method for measuring the lens mounting flange distance and center offset integrated measurement optical path based on any one of claims 1 to 3, characterized in that: Including lens mounting flange distance measurement method and lens center deviation measurement method; The lens mounting flange distance measurement method comprises the following steps: Step 1: preliminarily adjusting the system to be tested so that the light passing through the converging lens (7) converges at the vertex of the mirror surface of the lens to be tested (9), and after being reflected by the lens to be tested (9), passes through the converging lens (7) again for collimation, and the collimated light passes through the rear beam splitter prism (6) and the front beam splitter prism (5) to propagate to the energy converging off-axis parabolic mirror (12), and after being converged by the energy converging off-axis parabolic mirror (12), enters the optical power detector (14) through the incident pinhole plate (13), and moves the system to be tested forward and backward so that the converging point of the converging lens (7) is respectively located at the vertex of the mirror surface of the lens to be tested (9), the front part of the vertex of the mirror surface of the lens to be tested (9), and the rear part of the vertex of the mirror surface of the lens to be tested (9); recording the position information of the system to be tested corresponding to the maximum value detected by the optical power detector (14) as the position information of the system to be tested when the converging point of the converging lens (7) is located at the vertex of the mirror surface of the lens to be tested (9); Step 2: preliminarily adjusting the system to be tested so that the light passing through the converging lens (7) converges at the end face of the lens holder (8) to be tested, and after being reflected by the end face of the lens holder (8) to be tested, passes through the converging lens (7) again for collimation, and the collimated light passes through the rear beam splitter prism (6) and the front beam splitter prism (5) to propagate to the energy converging off-axis parabolic mirror (12), and after being converged by the energy converging off-axis parabolic mirror (12), enters the optical power detector (14) through the incident pinhole plate (13), and moves the system to be tested back and forth so that the converging point of the converging lens (7) is respectively located at the end face of the lens holder (8) to be tested, the front end face of the lens holder (8) to be tested, and the rear end face of the lens holder (8) to be tested; and recording the position information of the system to be tested corresponding to the maximum value detected by the optical power detector (14) as the position information of the system to be tested when the converging point of the converging lens (7) is located at the end face of the lens holder (8) to be tested; Step 3: Subtract the position information recorded in step 2 from that in step 1 to obtain the lens mounting flange focal distance of the system to be tested; The lens center deviation measurement method comprises: adjusting the position of the system to be measured or replacing the converging lens (7) so that the light rays converged by the converging lens (7) converge at the spherical center of the mirror surface of the lens to be measured (9), the converging light rays are reflected by the surface to be measured of the lens to be measured (9) and return along the original path, the return light rays are collimated by the converging lens (7), and then reflected by the rear beam splitting prism (6) to the imaging converging off-axis parabolic mirror (10), and are converged by the imaging converging off-axis parabolic mirror (10) to form an image in the area array CCD camera (11); rotating the lens holder (8) to be measured around the central axis, if the position of the circular light spot image in the area array CCD camera (11) remains unchanged, then there is no deviation between the optical axis of the lens to be measured (9) and the center line of the outer circle of the lens holder (8) to be measured; if the circular light spot image in the area array CCD camera (11) moves along a circular trajectory, then there is a deviation between the optical axis of the lens to be measured (9) and the center line of the outer circle of the lens holder (8) to be measured, and the center deviation of the system to be measured is obtained according to the diameter of the circular trajectory.

8. The measuring method according to claim 7, characterized in that: The specific process of obtaining the center deviation of the system to be measured based on the diameter of the circular trajectory is as follows: The circular trajectory diameter D can be obtained by fitting the circular trajectory using a circle fitting algorithm; Then, the center deviation θ is obtained according to the formula D = 2βRtan(2θ); Where: D is the diameter of the trajectory circle; β is the vertical axis magnification of the optical system; R is the radius of curvature of the lens to be tested; θ is the angle of the center deviation.

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