Optical instrument focusing straightness measuring device

Abstract

The utility model provides a kind of optical instrument focusing straightness measuring device, including the optical instrument to be measured, drive assembly, and the coaxial arrangement of light source, target, half-transmission half-reflection mirror and plane reflection component in proper order;The light source is used to illuminate target and produce target light, target light is transmitted to plane reflection component after half-transmission half-reflection mirror, after reflection plane reflection component, original road returns to the reflecting surface of half-transmission half-reflection mirror, and the optical instrument to be measured is arranged on the reflected light path of half-transmission half-reflection mirror;Drive assembly drives plane reflection component to move along the optical axis direction of light source, to change the optical distance between target and the optical instrument to be measured.The utility model changes the optical distance between target and the optical instrument to be measured by fixed target, deflects light path using half-transmission half-reflection mirror, simultaneously moves plane reflection component, realizes optical instrument focusing straightness measurement, and measurement precision is high, easy to operate, and high efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of optical equipment testing technology, and specifically relates to a device for measuring the focusing straightness of optical instruments. Background Technology

[0002] The current method for measuring and calibrating the focusing straightness of internal focusing telescopes adopts the requirements of "GB / T 1958-2017 Product Geometric Technical Specification (GPS) Geometric Tolerance Inspection and Verification". The method involves moving the target on a straight ruler to change the optical distance between the target and the internal focusing telescope. By using the focusing function of the internal focusing telescope, the target at different positions is clearly imaged. Then, the focusing straightness of the internal focusing telescope is verified by recording the deviation between the center image position of the target and the center position of the instrument under test.

[0003] However, this method of using a straight ruler to move a target to check the focusing straightness of an internal focusing telescope has the following disadvantages: (1) Using the straight ruler to check the focusing straightness of an internal focusing telescope, the accuracy of the straight ruler determines the calibration accuracy, resulting in low accuracy; (2) Long-stroke calibration conditions are limited. Utility Model Content

[0004] The purpose of this invention is to provide a device for measuring the straightness of focusing in optical instruments, which can at least solve some of the defects existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An optical instrument focusing linearity measuring device includes an optical instrument under test, a driving component, and a light source, a target, a semi-transparent mirror, and a plane reflection component arranged coaxially in sequence. The light source illuminates the target to generate target light, which passes through the semi-transparent mirror and is incident on the plane reflection component. After being reflected by the plane reflection component, the light returns to the reflecting surface of the semi-transparent mirror. The optical instrument under test is arranged on the reflected light path of the semi-transparent mirror. The driving component drives the plane reflection component to move along the optical axis of the light source to change the optical distance between the target and the optical instrument under test.

[0007] Furthermore, the aforementioned optical instrument focusing straightness measuring device also includes a focusing component, which is disposed in the optical path between the semi-transparent mirror and the optical instrument under test.

[0008] Furthermore, the planar reflector includes a corner cube prism and a prism mounting base. The corner cube prism is mounted on the prism mounting base, with its bottom surface facing the semi-transparent mirror. The bottom surface of the corner cube prism is perpendicular to the light transmitted by the semi-transparent mirror. The prism mounting base is connected to the power output end of the drive assembly.

[0009] Furthermore, the planar reflective assembly includes an optical flat and an optical flat mounting base. The optical flat is mounted on the optical flat mounting base, and the reflective surface of the optical flat is perpendicular to the light transmitted by the semi-transparent mirror. The optical flat mounting base is connected to the power output terminal of the driving assembly.

[0010] Furthermore, the planar reflection assembly also includes an autocollimator, which is arranged aligned with the side of the optical flat that faces away from the reflective surface.

[0011] Furthermore, the driving assembly includes a motor, a lead screw, and a sliding guide rail. The axes of the lead screw and the sliding guide rail are both arranged parallel to the optical axis of the light source. One end of the lead screw is connected to the movable end of the motor. The bottom of the planar reflector is slidably connected to the sliding guide rail, and the planar reflector is drivenly connected to the lead screw.

[0012] Furthermore, the drive assembly also includes a displacement sensor for measuring the moving distance of the planar reflector assembly.

[0013] Furthermore, the target is provided with graduations.

[0014] Furthermore, the semi-transparent mirror is arranged at a 45° angle to the optical axis of the light source.

[0015] Furthermore, the light source is a monochromatic light source.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] The optical instrument focusing straightness measuring device provided by this utility model has a simple structure. By fixing a target and using a semi-transparent mirror to deflect the optical path, while moving the planar reflection component, the optical distance between the target and the optical instrument under test is changed. This method of using optical means to change the optical distance between the target and the optical instrument under test to check and calibrate the focusing straightness of the optical instrument under test overcomes the problem that the accuracy of existing focusing straightness measurement relies on the accuracy of the straight ruler itself, greatly improving the measurement accuracy. Moreover, it can break through the limitation of the length of the straight ruler and be used for focusing straightness calibration of long-stroke optical distances, thus increasing the applicable range of focusing straightness measurement.

[0018] The present invention will be further described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the optical instrument focusing straightness measuring device using a cornerstone prism in the embodiment of this utility model;

[0020] Figure 2 This is a schematic diagram of the optical path of the planar reflective component using a cornerstone prism in an embodiment of this utility model;

[0021] Figure 3 This is a schematic diagram of the optical path of the planar reflection component using an optical flat in this embodiment of the present invention;

[0022] Figure 4 This is an assembly diagram of the light source, target, and semi-transparent mirror in an embodiment of this utility model;

[0023] Figure 5 This is a schematic diagram of the assembly of the driving component and the corner cube prism in an embodiment of this utility model;

[0024] Figure 6 This is a schematic diagram of the assembly of the driving component and the optical flat in an embodiment of this utility model.

[0025] Explanation of reference numerals in the attached diagram: 1. Light source; 2. Target; 3. Semi-transparent mirror; 4. Cornerstone prism; 5. Focusing component; 6. Optical instrument under test; 7. Optical flat; 8. Autocollimator; 9. Motor; 10. Drive screw; 11. Sliding guide rail; 12. Displacement sensor; 13. Prism mounting base; 14. Optical flat mounting base. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0027] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, abutting connections, or integral connections. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0030] like Figures 1 to 6 As shown, this embodiment provides an optical instrument focusing linearity measurement device, including an optical instrument under test 6, a driving component, and a light source 1, a target 2, a semi-transparent mirror 3, and a plane reflection component arranged coaxially in sequence; the light source 1 is used to illuminate the target 2 to generate target light, the target light passes through the semi-transparent mirror 3 and is incident on the plane reflection component, and after being reflected by the plane reflection component, it returns to the reflecting surface of the semi-transparent mirror 3 along the original path, and the optical instrument under test 6 is arranged on the reflected light path of the semi-transparent mirror 3; the driving component drives the plane reflection component to move along the optical axis of the light source 1 to change the optical distance between the target 2 and the optical instrument under test 6.

[0031] Among them, the optical instrument under test 6 has a focusing function, such as an internal focusing telescope.

[0032] The specific process of measuring the focusing straightness of the optical instrument under test using the above-mentioned measuring device includes the following steps:

[0033] S1. Construct the detection optical path according to the above-designed optical instrument focusing straightness measuring device, so that the light source 1 illuminates the target 2, the target light passes through the semi-transparent and semi-reflective mirror 3 and enters the plane reflection component, after being reflected by the plane reflection component, it returns to the reflection surface of the semi-transparent and semi-reflective mirror 3, and enters the optical instrument under test 6 after being reflected by the semi-transparent and semi-reflective mirror 3.

[0034] Before starting the measurement, focus the optical instrument under test 6 to the closest focal position and control the movement of the plane reflection component so that the target image can be clearly seen in the optical instrument under test 6; then adjust the angle position of the optical instrument under test 6 so that the center of the target image coincides with the center of the optical instrument under test 6, which is used as the zero point for measurement recording.

[0035] S2. Design multiple measurement points along the optical axis of the light source 1, and move the planar reflection component to each measurement point in sequence. At each measurement point, through the focusing function of the optical instrument under test 6, the target image corresponding to the planar reflection component at that measurement point can be clearly seen in the optical instrument under test 6, and the relative position deviation data between the target image center and the center of the optical instrument under test 6 is recorded.

[0036] In some embodiments, the relative position of the target imaging center with respect to the center of the optical instrument under test (OUT) can be recorded using the pixel coordinates (x, y) of the imaging detector of the OUT 6. Specifically, the center position of the OUT 6 is used as the zero-point reference, and its pixel coordinates are marked as (0, 0). The deviation distances between the target imaging center and the center of the OUT 6 on the X-axis and Y-axis are x and y, respectively. Then, (x, y) is used as the position of the target imaging.

[0037] Preferably, when the planar reflection component moves to each measurement point, it is designed to move along the optical axis of the light source 1 from the closest focal position of the optical instrument under test 6 to the far focal position, and the distance moved each time is equal. The distance moved each time can be adapted to different optical instruments under test 6.

[0038] S3. Based on the relative positional deviation data between the target imaging center and the center of the optical instrument under test 6 corresponding to different measurement points, the focusing straightness of the optical instrument under test 6 is calculated.

[0039] Specifically, the process of calculating the focusing straightness of the optical instrument under test 6 based on the relative position deviation data between the target imaging center position recorded at different measurement points and the center of the optical instrument under test 6 is as follows: The pixel coordinate data of the target imaging center recorded at different measurement points are fitted to generate a deviation curve. The PV value of the deviation curve (i.e., the difference between the highest and lowest points of the deviation curve) is multiplied by the pixel size of the imaging detector of the optical instrument under test to obtain the focusing straightness of the optical instrument under test 6.

[0040] In this embodiment, by fixing the target 2 and using the semi-transparent mirror 3 to deflect the optical path, while simultaneously moving the planar reflection component to change the optical distance between the target 2 and the optical instrument under test 6, the full-range focusing scenario of the optical instrument under test 6 from near focus to far focus can be simulated. Whether the optical instrument under test 6 is a short-stroke miniature internal focusing telescope or a long-stroke geodetic instrument telescope, it can be adapted for measurement by adjusting the movement range of the planar reflection component. The applicable range is far greater than the existing measurement method of fixing the reference with a straight ruler. Moreover, this embodiment uses optical methods to change the optical distance between the target and the optical instrument under test to check and calibrate the focusing straightness of the optical instrument under test, overcoming the problem that the accuracy of existing focusing straightness measurement relies on the accuracy of the straight ruler itself, and greatly improving the measurement accuracy.

[0041] When measuring a long-range focusing optical instrument 6, for example, when the total distance from the nearest focal length to the far focal length of the optical instrument 6 is greater than 1m, in order to ensure that the target 2 is clearly imaged in the optical instrument 6, a preferred embodiment is to set a focusing component 5 in the optical path between the semi-transparent mirror 3 and the optical instrument 6, so that the reflected light from the semi-transparent mirror 3 is focused by the focusing component 5 and enters the optical instrument 6. When the brightness of the target 2 image is insufficient or there are slight aberrations, the focusing component 5 can optimize the image quality of the target 2, ensuring that the image of the target 2 can still be clearly observed when focusing at a long distance. The focusing component 5 can be an existing optical element with focusing function, such as a focusing lens, the specific structure of which will not be described here.

[0042] Optimized, the light source 1 is preferably a monochromatic light source with high stability (such as a green LED) to avoid blurring of the target 2 image due to color difference or brightness fluctuation of the light source 1, and to ensure that the edge of the target 2 image in the optical instrument 6 under test is clear, providing a clear imaging basis for deviation judgment.

[0043] Optionally, the target 2 can be a symmetrical target such as a crosshair reticle, whose center is easy to locate. In this embodiment, the target 2 serves as an optical reference point. The offset of its image in the optical instrument 6 under test directly corresponds to the deviation of the focusing straightness. Therefore, the target 2 is fixed on a stable support to avoid shaking itself, so as to minimize the random errors caused by external environmental factors during measurement.

[0044] Furthermore, the target 2 is designed with fine graduations, which not only measure the overall deviation between the target center and the center of the optical instrument 6 under test, but also identify additional errors such as image tilt and image distortion that may accompany the focusing process through local deformation and misalignment of the graduations. This avoids judging straightness solely by center offset while ignoring other optical defects, thereby further improving measurement accuracy. Moreover, the fine graduations on the target 2 can serve as an internal calibration benchmark to achieve self-verification of measurement data. For example, during the measurement process, the actual magnification of the optical instrument 6 under test can be calculated by reading the number of imaging pixels at known graduation intervals on the target 2, verifying the magnification stability of the imaging system. If the magnification drifts with the focusing stroke, a magnification correction coefficient can be introduced into the focusing straightness calculation, thereby improving the accuracy of the final result.

[0045] Specifically, the semi-transparent and semi-reflective mirror 3 is installed at a 45° angle to the optical axis, and the surface coating is uniform, which reduces energy loss and optical axis offset during light transmission / reflection, and avoids insufficient imaging brightness or offset due to uneven beam splitting.

[0046] In some embodiments, such as Figure 1 , Figure 2 and Figure 5As shown, the planar reflective assembly includes a corner cube prism 4 and a prism mounting base 13. The corner cube prism 4 is mounted on the prism mounting base 13 to ensure the stability of the corner cube prism 4 during movement. The bottom surface of the corner cube prism 4 faces the semi-transparent mirror 3, and the bottom surface of the corner cube prism 4 is perpendicular to the light transmitted by the semi-transparent mirror 3, ensuring that the light incident on the corner cube prism 4 can return to the semi-transparent mirror 3 along its original path after reflection. The prism mounting base 13 is connected to the power output end of the driving assembly, which drives the corner cube prism 4 to move along the optical axis of the light source 1. In this embodiment, the corner cube prism 4 is used. Compared with ordinary planar reflectors, it is not sensitive to slight tilting of its own installation. Even if there is a slight attitude deviation during movement, the reflected light can still accurately return, effectively avoiding system errors introduced by the offset of the reference optical axis. In this embodiment, the shape and size of the corner cube prism 4 can be designed according to actual conditions, and a hollow corner cube can also be used.

[0047] In other embodiments, such as Figure 3 and Figure 6 As shown, the planar reflective assembly includes an optical flat 7 and an optical flat mounting base 14. The optical flat 7 is mounted on the optical flat mounting base 14 to ensure the stability of the movement of the optical flat 7. The reflective surface of the optical flat 7 is perpendicular to the light transmitted by the semi-transparent mirror 3. The optical flat mounting base 14 is connected to the power output end of the driving assembly, and the driving assembly drives the optical flat 7 to move along the optical axis of the light source 1.

[0048] Preferably, the planar reflection assembly further includes an autocollimator 8, which is arranged opposite to the side of the optical flat 7 that faces away from the reflective surface, in order to detect the attitude deviation of the optical flat 7 during movement, and to ensure that the light incident on the reflective surface of the optical flat 7 can return to the semi-transparent mirror 3 along the original path after being reflected on the optical flat 7.

[0049] As one specific implementation method, such as Figure 5 and Figure 6 As shown, the driving assembly includes a motor 9, a transmission screw 10, and a sliding guide rail 11. The axes of the transmission screw 10 and the sliding guide rail 11 are both arranged parallel to the optical axis of the light source 1. One end of the transmission screw 10 is connected to the movable end of the motor 9. The bottom of the planar reflection assembly is slidably connected to the sliding guide rail 11, and the planar reflection assembly is connected to the transmission screw 10 in a transmission connection. The motor 9 drives the transmission screw 10 to rotate, thereby driving the prism mounting base 13 / optical flat mounting base 14 to move linearly along the transmission screw 10. At the same time, the sliding guide rail 11 guides the movement of the prism mounting base 13 / optical flat mounting base 14.

[0050] Furthermore, the drive assembly also includes a displacement sensor 12 for measuring the moving distance of the planar reflector assembly, so as to accurately feedback the specific position of the planar reflector assembly.

[0051] In summary, the optical instrument focusing straightness measuring device provided by this utility model has a simple structure. By fixing a target and using a semi-transparent mirror to deflect the optical path, while simultaneously moving the planar reflection component to change the optical distance between the target and the optical instrument under test, this method of using optical means to change the optical distance between the target and the optical instrument under test to check and calibrate the focusing straightness of the optical instrument under test overcomes the problem that the accuracy of existing focusing straightness measurement relies on the accuracy of the straight ruler itself, greatly improving the measurement accuracy. Moreover, it can break free from the limitation of the length of the straight ruler and be used for focusing straightness calibration of long-stroke optical distances, thus expanding the applicable range of focusing straightness measurement.

[0052] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A device for measuring the straightness of focusing in an optical instrument, characterized in that: It includes the optical instrument under test, the driving component, and the light source, target, semi-transparent and semi-reflective mirror and plane reflection component arranged coaxially in sequence; The light source is used to illuminate the target and generate target light. The target light passes through the semi-transparent mirror and is incident on the planar reflection component. After being reflected by the planar reflection component, it returns to the reflecting surface of the semi-transparent mirror. The optical instrument under test is arranged on the reflected light path of the semi-transparent mirror. The driving component drives the planar reflection component to move along the optical axis of the light source to change the optical distance between the target and the optical instrument under test.

2. The optical instrument focusing straightness measuring device as described in claim 1, characterized in that: It also includes a focusing component, which is disposed in the optical path between the semi-transparent mirror and the optical instrument under test.

3. The optical instrument focusing linearity measuring device as described in claim 1 or 2, characterized in that: The planar reflector includes a corner cube prism and a prism mounting base. The corner cube prism is mounted on the prism mounting base, with its bottom surface facing the semi-transparent mirror. The bottom surface of the corner cube prism is perpendicular to the light transmitted by the semi-transparent mirror. The prism mounting base is connected to the power output end of the drive assembly.

4. The optical instrument focusing straightness measuring device as described in claim 1 or 2, characterized in that: The planar reflective assembly includes an optical flat and an optical flat mounting base. The optical flat is mounted on the optical flat mounting base, and the reflective surface of the optical flat is perpendicular to the light transmitted by the semi-transparent mirror. The optical flat mounting base is connected to the power output terminal of the drive assembly.

5. The optical instrument focusing straightness measuring device as described in claim 4, characterized in that: The planar reflection assembly also includes an autocollimator, which is arranged facing the side of the optical flat that is away from the reflective surface.

6. The optical instrument focusing straightness measuring device as described in claim 1 or 2, characterized in that: The drive assembly includes a motor, a lead screw, and a sliding guide rail. The axes of the lead screw and the sliding guide rail are both arranged parallel to the optical axis of the light source. One end of the lead screw is connected to the movable end of the motor. The bottom of the planar reflector is slidably connected to the sliding guide rail, and the planar reflector is driven by the lead screw.

7. The optical instrument focusing straightness measuring device as described in claim 6, characterized in that: The drive assembly also includes a displacement sensor for measuring the distance the planar reflector moves.

8. The optical instrument focusing straightness measuring device as described in claim 1 or 2, characterized in that: The target has graduations.

9. The optical instrument focusing straightness measuring device as described in claim 1 or 2, characterized in that: The semi-transparent mirror is arranged at a 45° angle to the optical axis of the light source.

10. The optical instrument focusing straightness measuring device as described in claim 1 or 2, characterized in that: The light source is a monochromatic light source.

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