Long range optical surface figure detection apparatus and method of use thereof

Abstract

The application relates to a long-range optical surface shape detection device and a use method thereof. The device comprises a plurality of mobile optical heads arranged in a rectangular array and connected to form an integral structure. The measurement directions of all the mobile optical heads are the same, and the measurement ends are located on one side of the integral structure. The plurality of mobile optical heads are connected to form an integral structure through a cuboid-shaped outer shell. A plurality of longitudinal and transverse partition plates are arranged in the outer shell, and the inner part of the outer shell is correspondingly divided into a plurality of vertical mounting spaces arranged in a rectangular array. A pigtail, a beam splitter, a single-hole screen, a Fourier transform lens and a surface array detector are arranged in each mounting space. One mounting space corresponds to one mobile optical head and faces the mirror surface to be measured. The device integrates a plurality of mobile optical heads into one detection integral structure. All the measurement points of the mirror surface can be measured at one time, the efficiency is greatly improved, and no fixed optical head correction is needed.

Description

Technical Field

[0001] This invention belongs to the field of measurement device technology in physics, characterized by the use of optical methods, and specifically relates to a long-range optical surface shape detection device and its usage method. Background Technology

[0002] Long-range optical surface shape inspection involves high-precision optical products and requires strict surface shape inspection. Existing technologies such as CN205505988U, CN205642307U, CN205505990U, CN205505989U, CN110926367A, and CN111024000A are all researching how to more accurately inspect the surface shape (angle) of long-range optical surfaces.

[0003] A mirror product involving long-range optical surface shape inspection has a relatively large mirror size, such as 1-1.2 meters in length and about 0.2 meters in width, requiring periodic inspection and verification. Currently, during inspection, the mirror to be tested is moved onto an optical platform, and the moving optical head moves with a linear translation stage above the platform to perform point-by-point horizontal scanning measurements on the mirror below. After obtaining the measurement results point by point, the measurements are reconstructed to achieve angle measurement. For detailed information, please refer to CN110926367A or CN205505988U. However, there are two prominent problems. First, the mirror needs to be moved to a dedicated optical platform for inspection, and after inspection, it needs to be removed and reinstalled in its actual use position. For high-precision mirrors, due to movement, changes in gravity, etc., there is a problem that the actual use condition does not match the measurement condition. If the inspection could be performed while the mirror is in use, it would be a more ideal method. Secondly, the testing is time-consuming. At each testing point, in addition to testing the moving optical head, which inevitably wobbles as it moves with the linear translation stage, the detection optical path is not affected, but the area array detector (CCD) inside the moving optical head is affected by the wobbling, thus affecting the detection accuracy. Therefore, at each testing point, the fixed optical head is also required to test and correct the moving optical head to eliminate measurement deviations. Generally, it takes about one minute to test one point. The distance between testing points is on the order of millimeters or centimeters. Testing the entire mirror surface, which is 1-1.2 meters long and 0.2 meters wide, takes a long time. It is obviously impractical to conduct such a long test in the usage state.

[0004] Therefore, the first problem to be solved is how to perform optical surface inspection more efficiently and quickly.

[0005] The movable optical head used in CN205505988U consists of a housing and a pigtail, beam splitter, single-aperture screen, lens, and area array detector installed in the housing. It applies the principle of pinhole (screen aperture) and the propagation of the detection beam along the normal of the mirror surface. This invention studies and improves upon this technical solution to solve the aforementioned problems. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is to provide another long-range optical surface shape detection device and its usage method, to solve the problem of how to perform long-range optical surface detection more efficiently and quickly, while ensuring the accuracy of the detection.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A long-range optical surface shape detection device includes multiple moving optical heads arranged in a rectangular array and connected to each other to form an integral structure. The measurement directions of all moving optical heads are in the same direction and the measurement ends are all located on one side of the integral structure.

[0009] To further improve the above technical solution, the multiple mobile optical heads are connected into an integral structure through a rectangular outer shell. The shell is provided with several longitudinally and transversely arranged partitions, which divide the interior of the shell into multiple vertical installation spaces in a rectangular array. Each installation space is provided with a pigtail, a beam splitter, a single-aperture screen, a Fourier transform lens, and an area array detector. Each installation space corresponds to one of the mobile optical heads, and the measurement direction is downward.

[0010] Furthermore, within a single installation space, the area array detector is positioned above the Fourier transform lens, the single-aperture screen is flush against the bottom surface of the Fourier transform lens, and the beam splitter is positioned below the single-aperture screen. A reflector is added within the installation space and located to one side of the beam splitter, with a pigtail vertically positioned above the reflector. The beam emitted from the pigtail is reflected by the reflector and then by the beam splitter onto the surface of the optical device under test. It is then reflected back to the beam splitter by the surface of the optical device under test, and a portion of the reflected beam passes through the aperture of the single-aperture screen and is reflected back to the Fourier transform lens. This reflected beam is then reflected by the Fourier transform lens along a direction perpendicular to the normal of the measurement point on the surface of the optical device under test to the area array detector, forming a measurement spot on the area array detector.

[0011] Furthermore, the image point formed by the beam exit point of the pigtail and the reflection of the beam splitter is located at the center of the aperture of the single-aperture screen.

[0012] Furthermore, the diameter of the hole on the single-hole screen is 4m, the single-hole screen is circular with an outer diameter of 8m, and the longitudinal and transverse spacing of the rectangular array is 1 cm.

[0013] Furthermore, the number of moving optical heads in the width direction is 12-20, and the number of moving optical heads in the length direction is 50-70.

[0014] The present invention also relates to a method of using the above-mentioned long-range optical surface shape detection device, wherein the area of ​​the measuring end of the overall structure is smaller than the area of ​​the long-range optical surface to be measured, and the surface to be measured is translated to perform multiple detections, with adjacent detections having partially overlapping measurement points for self-correction.

[0015] For example: the number of moving optical heads in the width direction is 20, the number of moving optical heads in the length direction is 60, for a total of 1200; the length of the surface to be measured is 1 meter and the width is 0.2 meters;

[0016] The device is positioned at one end of the surface to be tested for detection, and then moved to the other end of the surface to be tested for detection. During the two detection processes, 400 measurement points overlap for self-correction.

[0017] The present invention also relates to another method of using the above-mentioned long-range optical surface shape detection device, in which the area of ​​the measuring end of the overall structure corresponds to the area of ​​the long-range optical surface to be measured, the two are parallel and facing each other and fixedly set, and all the measuring points corresponding to the surface to be measured can be measured in one test.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The long-range optical surface shape detection device of the present invention integrates multiple moving optical heads into a detection unit. In one detection, all measurement points corresponding to the long-range optical surface can be measured, which greatly improves efficiency. Since multiple moving optical heads are integrated into a detection unit, the difference in measurement values ​​between individual optical heads in one detection is the effective measurement data. Therefore, it is not necessary to fix the optical head to correct the device, which reduces this part of the cost.

[0020] 2. The long-range optical surface shape detection device of the present invention utilizes the principle of a pinhole and the propagation of the detection beam along the normal of the mirror surface in the moving optical head. Because only the beam passing through the pinhole is captured, the active parts of each optical component can be very small. Therefore, the moving optical head can be miniaturized, requiring only the focal length of a lens. fDue to the need for sufficient length, the movable optical head is specifically elongated; multiple movable optical heads are integrated into a cuboid-shaped outer shell. Because smaller spacing between adjacent detection points results in higher accuracy for long-range optical surface shape detection, this invention adds a reflector within the installation space of the outer shell and vertically positions the fiber optic cable. This further reduces the size of the movable optical head, thereby improving the accuracy of long-range optical surface shape detection and preventing damage from fiber optic cable bending. This device can perform detection quickly, and can even perform real-time detection of actually installed mirror surfaces, making it highly practical.

[0021] 3. The long-range optical surface shape detection device of the present invention, combined with an appropriate method of use, can perform multiple translational detections, as long as the measurement points of two adjacent detections partially overlap, the amount of oscillation during the translational process can be obtained by calculating the overlapping measurement points, thereby self-correcting the detection data; thus, the device size can be smaller and the cost lower, and it does not require fixing the optical head for correction, making it suitable for rapid measurement of large-sized mirror surfaces.

[0022] If the area of ​​the mirror to be tested is small, the area of ​​the measuring end of this device can be made to correspond to the size of the area of ​​the mirror to be tested, be parallel to each other and fixed, so that all the measurement points corresponding to the optical surface can be measured at one time, realizing rapid measurement of small-sized mirrors to be tested; and this state can be fixed to realize real-time monitoring. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the long-range optical surface shape detection device from an upward viewing angle, as shown in the embodiment.

[0024] Figure 2 This is a schematic diagram of the lateral angle structure of the long-range optical surface shape detection device in an embodiment (only one internal structure is shown).

[0025] Figure 3 This is a plan view of a method of using the long-range optical surface shape detection device according to an embodiment;

[0026] Figure 4 This is an overall schematic diagram of a method of using the long-range optical surface shape detection device according to an embodiment.

[0027] Figure 5 This is a perspective view of another method of using the long-range optical surface shape detection device according to the embodiment;

[0028] The components include: optical head unit 1, overall structure 2, outer shell 3, translation stage 4, optical platform 5, installation space 31, reflector 7, pigtail 8, beam splitter 9, single aperture screen 10, Fourier transform lens 11, area array detector 12, optical surface to be measured 13, and measurement point 14. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] Please see Figure 1 , Figure 2 The long-range optical surface shape detection device in a specific embodiment includes multiple optical head units 1. The multiple optical head units 1 are arranged in a rectangular array and connected to each other to form an integral structure 2. The measurement directions of all optical head units 1 are in the same direction and the measurement ends are all located on one surface of the integral structure 2, specifically the bottom surface.

[0031] The long-range optical surface shape detection device of the embodiment integrates multiple optical head units 1 into a detection unit. In one detection, all measurement points corresponding to the long-range optical surface can be measured, which greatly improves efficiency. Since multiple optical head units 1 are a detection unit, the error introduced to each optical head unit 1 in one detection is the same, and the comparison data required for measurement is not affected. Therefore, it is not necessary to fix the optical head to correct the device, which reduces hardware costs.

[0032] In implementation, the multiple optical head units 1 are connected into a single structure 2 by a rectangular outer shell 3. The outer shell 3 contains several longitudinally and transversely arranged partitions, dividing the interior into multiple vertical mounting spaces 31 arranged in a rectangular array. Each mounting space 31 contains a pigtail 8, a beam splitter 9, a single-aperture screen 10, a Fourier transform lens 11, and an area array detector 12. Each mounting space 31 and its contents form one optical head unit 1, with the measurement direction facing the mirror surface to be measured. Specifically, within the mounting space 31, the area array detector 12 is positioned above the Fourier transform lens 11, the single-aperture screen 10 is flush against the bottom surface of the Fourier transform lens, the beam splitter 9 is positioned below the single-aperture screen 10 and as close as possible to it, a reflector 7 is added to the mounting space 31 and located to one side of the beam splitter 9, and the pigtail 8 is vertically positioned above the reflector 7. It is understood that the pigtail 8 is connected to the light source (not shown in the figure) via optical fiber.

[0033] In use, the input light beam is emitted from the pigtail 8, reflected by the reflector 7, and then reflected by the beam splitter 9 onto the surface of the optical device under test. The beam is then reflected back to the beam splitter 9, and a portion of the reflected beam passes through the aperture of the single-aperture screen 10 and is reflected to the Fourier transform lens 11. According to the principle of normal tracing, this reflected beam always propagates along the normal direction of the measurement point on the mirror surface under test. After passing through the Fourier transform lens 11, it converges onto the area array detector 12, forming a measurement spot on the detector. By appropriately configuring the positions and angles of the optical elements, the image point formed by the reflection of the beam from the pigtail 8 by the beam splitter 9 is located at the center of the aperture of the single-aperture screen 10. Thus, the beam emitted from the pigtail 8 can be considered as a beam emitted from the center point of the aperture of the single-aperture screen 10.

[0034] The detection device in this embodiment is a further optimization and improvement of the inventor's own invention. It adopts the principle of the moving optical head used in CN205505988U, and applies the principle of a pinhole (screen aperture) and the propagation of the detection beam along the normal of the mirror. Because only the beam passing through the pinhole is captured, the active parts of each optical component can be very small. Therefore, the moving optical head can be miniaturized, requiring only the focal length of a lens. f Due to the need for sufficient length, the optical head unit 1 in this device is specifically elongated. In this embodiment, multiple optical head units 1 are integrated into a cuboid outer shell 3. Furthermore, because a smaller distance between adjacent detection points results in higher accuracy for long-range optical surface shape detection, a reflector 7 is added within the installation space 31 of the outer shell 3, and the pigtail 8 is vertically positioned. This further reduces the volume of the optical head unit 1, thereby improving the accuracy of long-range optical surface shape detection and preventing damage from bending of the pigtail 8. The contents of the installation space 31 can be integrated into a single unit. Since each component is small, the cost is low, with only the area array detector 12 having a slightly higher cost. Depending on the number of integrated optical head units 1, the cost of this device should be in the tens of thousands or hundreds of thousands of dollars. However, a single mirror product involved in long-range optical surface shape detection can be worth millions, and related application engineering costs typically require a budget of hundreds of millions. This device can perform rapid detection and even real-time detection of mirror surfaces under actual installation conditions, making it entirely worthwhile to implement.

[0035] Specifically, the diameter of the screen hole on the single-hole screen 10 can be 4m, the single-hole screen 10 is circular with an outer diameter of 8m, and the longitudinal and transverse spacing of the rectangular array is 1 cm. For the current actual size of the mirror surface, which is about 1-1.2 meters long and about 0.2 meters wide, the number of optical head units 1 in the width direction of this device can be 12-20, and the number of optical head units 1 in the length direction can be 50-70.

[0036] This method also provides a way to use the aforementioned long-range optical surface shape detection device. Regarding the manufacturing cost of this device, as mentioned earlier, in actual use, it is not necessary for the device to be set to the same width and length as the optical surface to be measured to avoid translation correction issues. The preferred number of moving optical heads 1 given earlier in the length direction is also not matched with a length of 1-1.2 meters. Because of the characteristics of this device, combined with an appropriate usage method, even with multiple translation measurements, as mentioned before, it is still not necessary to fix the optical heads for correction. The specific method is as follows:

[0037] Please see Figure 3 , Figure 4 When the size of this device is smaller than the size of the optical surface 13 to be measured, it is still possible to perform multiple tests on the optical surface 13 to be measured by translation. As long as there are some overlapping measurement points 14 between two adjacent tests, the swing amount during the translation process can be obtained by solving the overlapping measurement points 14, thereby self-correcting the test data.

[0038] Specifically, for example, the number of optical heads 1 that move in the width direction of this device is 20, and the number of optical heads 1 that move in the length direction is 60, for a total of 1200. The long-range optical surface to be measured is 1 meter long and 0.2 meters wide, and is placed on the optical platform 5. During the measurement, the device is first placed at one end of the optical surface to be measured for detection, and then translated (the translation process is provided by the existing translation stage 4) to the other end of the optical surface to be measured for detection. During the two detection processes, 400 measurement points overlap each other for self-correction, and the entire mirror surface is detected in two steps.

[0039] This method is suitable for rapid measurement of large-sized mirror surfaces.

[0040] This method also provides another way to use the above-mentioned long-range optical surface shape detection device; please refer to [link to relevant documentation]. Figure 5 The area of ​​the measuring end of the overall structure 2 corresponds to the area of ​​the optical surface to be measured 13, and the two are parallel, facing each other and fixedly set. In this way, all the measurement points corresponding to the optical surface to be measured can be measured in one test. This method is suitable for rapid measurement of small-sized mirrors and can be fixed in this state for real-time monitoring.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A long-range optical surface shape detection device, comprising multiple moving optical heads, characterized in that: The multiple moving optical heads are arranged in a rectangular array and connected to each other to form an integral structure. The measurement directions of all moving optical heads are in the same direction and the measurement ends are all located on one side of the integral structure. The multiple movable optical heads are connected into an integral structure through a rectangular outer shell. The shell is provided with several longitudinally and transversely arranged partitions, which divide the interior of the shell into multiple vertical installation spaces in a rectangular array. Each installation space is provided with a pigtail, a beam splitter, a single-aperture screen, a Fourier transform lens and an area array detector. Each installation space corresponds to one of the movable optical heads, and the measurement direction is always towards the optical device under test. Within the installation space, the area array detector is positioned above the Fourier transform lens, the single-aperture screen is attached to the bottom surface of the Fourier transform lens, the beam splitter is positioned below the single-aperture screen, a reflector is added within the installation space and located to one side of the beam splitter, and the pigtail is vertically positioned above the reflector. Within a single installation space, the fiber optic beam is emitted, reflected by a mirror, and then reflected by a beam splitter onto the surface of the optical device under test. It is then reflected back to the beam splitter, and a portion of the reflected beam is reflected through the aperture of the single-aperture screen to the Fourier transform lens. This reflected beam is then reflected by the Fourier transform lens along a direction perpendicular to the normal of the measurement point on the surface of the optical device under test to the area array detector, forming a measurement spot on the area array detector.

2. The long-range optical surface shape detection device according to claim 1, characterized in that: The image point formed by the beam exit point of the pigtail and the reflection of the beam splitter is located at the center of the aperture of the single-aperture screen.

3. The long-range optical surface shape detection device according to claim 1 or 2, characterized in that: The diameter of the hole on the single-hole screen is 4m, the single-hole screen is circular with an outer diameter of 8m, and the longitudinal and transverse spacing of the rectangular array is 1 cm.

4. The long-range optical surface shape detection device according to claim 3, characterized in that: The number of moving optical heads in the width direction is 12-20, and the number of moving optical heads in the length direction is 50-70.

5. A method of using a long-range optical surface shape detection device, characterized in that: This method is a method of using the long-range optical surface shape detection device as described in any one of claims 1-3. The area of ​​the measuring end of the overall structure is smaller than the area of ​​the long-range optical surface to be measured. The surface to be measured is translated and detected multiple times. The measurement points of two adjacent detections partially overlap for self-correction.

6. The method of using the long-range optical surface shape detection device according to claim 5, characterized in that: The number of moving optical heads is 20 in the width direction and 60 in the length direction, for a total of 1200; the length of the surface to be measured is 1 meter and the width is 0.2 meters. The device is positioned at one end of the surface to be tested for detection, and then moved to the other end of the surface to be tested for detection. During the two detection processes, 400 measurement points overlap for self-correction.

7. A method of using a long-range optical surface shape detection device, characterized in that: This method is the method of using the long-range optical surface shape detection device as described in any one of claims 1-3. The area of ​​the measuring end of the overall structure corresponds to the area of ​​the long-range optical surface to be measured. The two are parallel, facing each other and fixedly set. All the measurement points corresponding to the surface to be measured can be measured in one test.

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