A self-collimator device based on orthogonal cross multi-slit group

Abstract

The present invention relates to an autocollimator device based on an orthogonal cross multi-slit group. A light source is located at the focus of a focusing lens, and a divergent light beam of the light source is converged by the focusing lens to uniformly illuminate the orthogonal cross multi-slit group grating plate to form a positioning light spot, and the orthogonal cross multi-slit group grating plate is located at the focal plane of the collimating objective lens; the positioning light spot light is reflected by a right-angle prism and a beam splitter prism, and then emitted from the collimating objective lens to irradiate the reflector to be measured; the light emitted by the collimating objective lens is reflected by the reflector to be measured and then returned, and is focused on the photosensitive surface of a planar array image detector after passing through the collimating objective lens and the beam splitter prism in sequence; the planar array image detector is used to image the positioning light spot, and realize high-precision monitoring of the position change of the positioning light spot image, and further calculate the deflection angles of the reflector to be measured in the x and y axis directions. The present invention improves the resolution of the autocollimator by averaging the image position twice.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectric detection and optical precision measurement, and more specifically, to an autocollimator device based on an orthogonal cross multi-slit group. Background Art

[0002] Angle measurement is an important part of metrology. With the advantage of non-contact measurement, autocollimator has become one of the most important angle measurement instruments and is widely used in scientific research, precision machinery manufacturing, engineering measurement and other fields. Early autocollimators were mechanical. Since the scale was observed by human eyes, the accuracy error was large and could not meet the needs of high-precision measurement. In recent years, with the development of optoelectronic device technology, photoelectric autocollimators have gradually replaced mechanical autocollimators, and the measurement accuracy, measurement range and degree of automation of autocollimators have also been greatly improved.

[0003] In the current mature autocollimator products, two linear array image detectors, or planar array image detectors, or position sensitive devices (PSDs) are generally used as image detectors. When dual linear array image detectors are used as autocollimator image detectors, it is easier to achieve a larger measurement range, but the optical system has to introduce a spectroscopic element, which will make the instrument structure more complicated, the volume will also increase accordingly, and the measurement resolution is difficult to further improve. Representative products include ELCOMAT HR produced by Germany's MOLLER company; when planar array detectors are used as autocollimator image detectors, the graticule is generally designed as a cross single slit structure to achieve two-dimensional angle measurement. The advantage of the single-structure slit design is that the image processing algorithm is simple, and its disadvantages are low resolution and poor stability. At present, most domestic autocollimator products use a combination of a cross single slit and a planar array detector. The advantages of using PSD as an image detector are good time response, fast response speed, high position resolution, and simple processing circuit, but due to the uneven surface resistance and dark current of the PSD device, nonlinear errors will occur during measurement, resulting in reduced measurement accuracy. Summary of the invention

[0004] In order to overcome the defects in the prior art, the present invention provides an autocollimator device based on an orthogonal cross multi-slit group, which effectively improves the resolution and measurement accuracy.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] An autocollimator device based on an orthogonal cross multi-slit group comprises a light source, a focusing lens, an orthogonal cross multi-slit group scribe plate, a right-angle prism, a beam splitter, a collimating objective lens, a reflector to be measured, and a planar array image detector; the light source is located at the focus of the focusing lens, the divergent light beams of the light source are converged by the focusing lens to uniformly illuminate the orthogonal cross multi-slit group scribe plate to form a positioning light spot, the orthogonal cross multi-slit group scribe plate is located at the focal plane of the collimating objective lens; the positioning light spot light passes through the straight After being reflected by the corner prism and the beam splitter, the light is emitted from the collimating objective lens and irradiated to the reflector to be measured; the light emitted from the collimating objective lens is reflected by the reflector to be measured and then returns, and is focused on the photosensitive surface of the area array image detector after passing through the collimating objective lens and the beam splitter in sequence; the area array image detector is used to image the positioning light spot and realize high-precision monitoring of the position change of the positioning light spot image; according to the principle of optical self-collimation, the deflection angles of the reflector to be measured in the x-axis and y-axis directions are calculated from the position offset of the positioning light spot.

[0007] According to the above technical scheme, the present invention adopts a planar array image detector and designs a graticule of an orthogonal cross multi-slit group. By averaging multiple rows and columns of the target light spot monitored by the planar array detector and averaging the positions of multiple slits, the position extraction of the autocollimation target image is better achieved. Compared with the position positioning of a single slit, the two averages can reduce the random error of the position positioning, thereby improving the angle measurement resolution of the autocollimator.

[0008] The autocollimator device based on the orthogonal cross multi-slit group described in the present invention improves the resolution of the autocollimator by averaging the image position twice. Compared with the detection scheme of the double-line array CCD, the present invention can not only improve the measurement resolution, but also reduce the size of the device. The whole device can adopt a USB data interface design, which can be connected to various data acquisition devices such as industrial computers and notebooks, thereby improving the versatility of the device.

[0009] Furthermore, the orthogonal cross multi-slit group dividing plate has multiple horizontal slits and multiple vertical slits that are perpendicular to each other, forming an orthogonal cross positioning image composed of multiple slits. In theory, the more slits there are, the higher the resolution of the autocollimator; the width of the slit needs to be considered in combination with the pixel size of the area array image detector; the length of the slit needs to be considered in combination with the angle measurement range, the focal length of the collimating objective lens, the focal length of the focusing lens, etc.

[0010] The device provided by the present invention designs a graticule of an orthogonal cross multi-slit group, which forms a cross image with a periodic structure through illumination by a light source. According to the error theory, when measuring n times with equal precision, the standard deviation of the arithmetic mean is 1 / √n of the standard deviation of a single measurement. As the number of measurements n increases, the closer the arithmetic mean is to the true value of the measurement, the smaller the random error of the measurement, thereby improving the system resolution and stability. Compared with the image positioning of the existing common cross single-slit graticule structure, when other parameters are the same, the average of the positions of N slit images is equivalent to the position of N independent single-slit images. The random error of the measurement will be reduced, and the measurement resolution and stability of the system can be improved by √N times; similarly, the position average of the M-row image of the area array detector can also improve the measurement resolution by √M times compared with the position of the single-row image of the linear array detector. According to the principle of optical autocollimation, the position change information of the image can be converted into the angle deflection information of the reflector to be measured, thereby realizing angle measurement.

[0011] Furthermore, the light at each point of the orthogonal cross multi-slit group dividing plate passes through the dichroic prism and the collimating objective lens in sequence to form parallel light output, and the parallel light reflected back by the reflector to be measured passes through the collimating objective lens and is focused on the photosensitive surface of the area array image detector. The dichroic prism is used to change the propagation direction of the light so as to separate the output light of the collimating objective lens from the incident light.

[0012] Furthermore, the orthogonal cross multi-slit group dividing plate and the photosensitive surface of the area array image detector are both placed at the focal plane of the collimating objective lens; the focal length of the collimating objective lens can be comprehensively considered based on measurement accuracy, measurement range, etc.

[0013] Furthermore, the focusing lens is an aspherical condenser lens with a scattering plane. After the divergent light from the light source placed at its focus is collimated, it helps to evenly illuminate the orthogonal cross multi-slit group graticule. The graticule, right-angle prism and beam splitter prism are directly pasted together, which can improve the overall stability of the device and make the structure simpler.

[0014] Furthermore, the image sensor of the area array image detector is a metal oxide semiconductor sensor or a charge coupled device sensor, and the area array image detector realizes real-time image display of the positioning light spot; the grayscale value of each pixel of the area array image detector is averaged by row and column respectively, and according to the geometric relationship, the displacement of the image after the column average represents the deflection angle of the reflector to be measured in the x direction, and the displacement of the image after the row average represents the deflection angle of the reflector to be measured in the y direction.

[0015] Furthermore, the area array image detector uses a high-precision image positioning algorithm to monitor the position changes of the two one-dimensional images averaged by rows and columns, and converts the changes in the position of the positioning light spot into the deflection angle of the reflector to be measured according to the principle of optical autocollimation; the angle measurement program based on the high-precision image positioning algorithm is installed in the host computer, and the image formed by the positioning light spot and the angle measurement results can be displayed in real time on the display interface. The program can add a variety of calculation modules as needed to realize a variety of measurement functions such as flatness and verticality, and expand the use scenarios of the device. The whole device is designed with a USB3.0 transmission interface, which is convenient for connecting a variety of devices to perform subsequent processing of the measurement data. The pixel size, processing speed, etc. of the area array image detector need to be comprehensively considered in combination with the accuracy and sampling rate requirements of the autocollimator device.

[0016] Furthermore, under ideal conditions, when the reflector to be measured is perpendicular to the optical axis of the autocollimator device, the corresponding angle measurement value is zero, the deflection angle of the reflector to be measured takes this as the absolute reference zero point, and the angle measurement value is the deflection angle relative to the absolute zero point.

[0017] Furthermore, the deflection angles of the reflector to be measured in the x and y directions are:

[0018]

[0019]

[0020] Where, Δd x , Δd y is the relative displacement of the one-dimensional image position after averaging by column and row, and f is the focal length of the collimating objective lens.

[0021] Furthermore, the light intensity stability of the light source is controlled by feedback of the grayscale value of the pixel of the area array image detector to enhance the stability of the device.

[0022] Compared with the prior art, the beneficial effects are:

[0023] 1. The present invention provides an autocollimator device based on an orthogonal cross multi-slit group, designs a graticule structure of an orthogonal cross multi-slit group, and adopts a high-resolution area array sensor as an image detector to realize dual-axis synchronous measurement. By averaging the area array image and the multi-slit group, random noise can be effectively reduced and the angle measurement resolution can be improved.

[0024] 2. The present invention glues the orthogonal cross multi-slit group dividing plate, right-angle prism and beam splitter prism into a whole with ultraviolet glue, which has a simple structure and improves the overall stability.

[0025] 3. The present invention utilizes image acquisition algorithms and data processing programs to display images detected by high-resolution area array sensors in real time, and calls built-in high-precision image positioning algorithms to perform high-precision monitoring of changes in the position of the positioning light spot. The present invention proposes that the stability of LED light intensity can be controlled by feedback of the grayscale value of the pixel of the area array image detector, thereby improving the measurement stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the optical self-collimation principle.

[0027] Figure 2 It is a principle diagram of the autocollimator device based on the orthogonal cross multi-slit group of the present invention.

[0028] Figure 3 The present invention is a schematic diagram of an implementation structure of an autocollimator device based on an orthogonal cross multi-slit group.

[0029] Figure 4 It is a schematic diagram of the local structure of the orthogonal cross multi-slit group dividing plate.

[0030] Figure 5 It is the actual imaging of the orthogonal cross multi-slit group graticule on the area array image detector.

[0031] Figure 6 It is the imaging of the orthogonal cross multi-slit group on the area array sensor (after column averaging).

[0032] Figure numerals: 1, light source; 2, focusing lens; 3, orthogonal cross multi-slit group dividing plate; 4, right-angle prism; 5, beam splitter; 6, collimating objective lens; 7, reflector to be measured; 8, area array image detector; 9, housing. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The present invention is described in one of the embodiments in combination with the specific implementation methods. Among them, the drawings are only used for exemplary descriptions, and only schematic diagrams are shown, not physical drawings, and cannot be understood as limitations on this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0034] In the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for exemplary explanations and cannot be understood as a limitation of this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances. In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text is to include three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that satisfy both A and B.

[0035] Embodiment 1:

[0036] like Figure 1 The figure shows the principle of optical autocollimation. A point light source is placed at the main focus A of the collimating objective lens. The emitted light is reflected by the beam splitter and then emitted through the objective lens, becoming a beam of parallel light parallel to the main optical axis. After being reflected by the reflector to be measured, it is re-converged on the focal plane of the collimating objective lens. According to the geometric relationship, the displacement d = |OB| of the self-collimating image point and the deflection angle θ of the reflector to be measured satisfy:

[0037] d=|OB|=f×tan(2θ) (Formula 1)

[0038] Where f is the focal length of the collimating lens. In the use scenario of the autocollimator, the deflection angle θ of the reflector to be measured is generally very small, so Formula 1 can be simplified to:

[0039] θ=d / 2f. (Formula 2)

[0040] It can be seen from Formula 2 that the deflection angle of the reflector to be measured can be obtained by simply using an image detector to monitor the position change of the autocollimator image.

[0041] like Figure 2As shown, this embodiment provides an autocollimator device based on an orthogonal cross multi-slit group, comprising a light source 1, a focusing lens 2, an orthogonal cross multi-slit group dividing plate 3, a right-angle prism 4, a beam splitter 5, a collimating objective lens 6, a reflector to be measured 7, and a planar array image detector 8; the light source 1 is located at the focus of the focusing lens 2, and the divergent light beams of the light source 1 are converged by the focusing lens 2 to uniformly illuminate the orthogonal cross multi-slit group dividing plate 3 to form a positioning light spot, and the orthogonal cross multi-slit group dividing plate 3 is located at the focal plane of the collimating objective lens 6; the positioning light spot The spot light is reflected by the right-angle prism 4 and the beam splitter prism 5, then emitted from the collimating objective lens 6 and irradiated to the reflector 7 to be measured; the light emitted from the collimating objective lens 6 is reflected by the reflector 7 to be measured and then returns, and is focused on the photosensitive surface of the area array image detector 8 after passing through the collimating objective lens 6 and the beam splitter prism 5 in sequence; the area array image detector 8 is used to image the positioning light spot and realize high-precision monitoring of the position change of the positioning light spot image. According to the principle of optical self-collimation, the deflection angles of the reflector 7 to be measured in the x-axis and y-axis directions are calculated from the position offset of the positioning light spot.

[0042] Among them, the orthogonal cross multi-slit group dividing plate 3 has multiple horizontal slits and multiple vertical slits that are perpendicular to each other, forming an orthogonal cross positioning image composed of multiple slits. In theory, the more slits there are, the higher the resolution of the autocollimator; the width of the slit needs to be comprehensively considered in combination with the pixel size of the area array image detector 8; the length of the slit needs to be comprehensively considered in combination with the angle measurement range, the focal length of the collimating lens 6, the focal length of the focusing lens 2, etc. The light at each point of the orthogonal cross multi-slit group dividing plate 3 passes through the beam splitter prism 5 and the collimating lens 6 in turn to form parallel light emission. The parallel light reflected back by the reflector 7 to be measured passes through the collimating lens 6 and is focused on the photosensitive surface of the area array image detector 8. The beam splitter prism 5 is used to change the propagation direction of the light to separate the outgoing light of the collimating lens 6 from the incident light. The orthogonal cross multi-slit group dividing plate 3 and the photosensitive surface of the area array image detector 8 are both placed at the focal plane of the collimating lens 6; the focal length of the collimating lens 6 can be comprehensively considered based on the measurement accuracy, measurement range, etc.

[0043] Among them, the area array image detector 8 uses a high-precision image positioning algorithm to monitor the position changes of two one-dimensional images after averaging by rows and columns, and converts the changes in the position of the positioning spot into the deflection angle of the reflector 7 to be measured according to the principle of optical self-collimation; the angle measurement program based on the high-precision image positioning algorithm is installed in the host computer, and the image formed by the positioning spot and the angle measurement results can be displayed in real time on the display interface. The program can add a variety of calculation modules as needed to realize various measurement functions such as flatness and verticality, thereby expanding the use scenarios of the device.

[0044] Furthermore, in an ideal state, when the reflector 7 to be measured is perpendicular to the optical axis of the autocollimator device, the corresponding angle measurement value is zero, and the deflection angle of the reflector 7 to be measured takes this as the absolute reference zero point, and the angle measurement value is the deflection angle relative to the absolute zero point.

[0045] The deflection angles of the reflector 7 to be measured in the x and y directions are:

[0046]

[0047]

[0048] Where, Δd x , Δd y is the relative displacement of the one-dimensional image position after averaging by column and row, and f is the focal length of the collimating objective lens.

[0049] In this embodiment, the light intensity stability of the light source 1 can also be controlled by feedback of the grayscale value of the pixels of the area array image detector 8 to enhance the stability of the device.

[0050] This embodiment adopts a planar array image detector 8 and designs a graticule of an orthogonal cross multi-slit group. By averaging multiple rows and columns of the target light spot monitored by the planar array detector and averaging the positions of multiple slits, the position extraction of the autocollimation target image is better achieved. Compared with the position positioning of a single slit, the two averages can reduce the random error of the position positioning, thereby improving the angle measurement resolution of the autocollimator.

[0051] This embodiment improves the resolution of the autocollimator by averaging the image positions twice. Compared with the detection scheme of the dual-line array CCD, the present invention can not only improve the measurement resolution, but also reduce the size of the device. The whole device can adopt a USB data interface design, which can be connected to various data acquisition devices such as industrial computers and notebooks, thereby improving the versatility of the device.

[0052] Embodiment 2:

[0053] like Figure 3As shown, it is a schematic diagram of the implementation structure of an autocollimator device based on an orthogonal cross multi-slit group, including a light source 1, a focusing lens 2, an orthogonal cross multi-slit group dividing plate 3, a right-angle prism 4, a beam splitter 5, a collimating objective lens 6, a reflector to be measured 7, a planar array image detector 8, and a housing 9. The light source 1 is located at the focus of the focusing lens 2. The divergent light beam of the light source 1 is converged by the focusing lens 2 and evenly illuminates the orthogonal cross multi-slit group dividing plate 3 to form a positioning light spot. The orthogonal cross multi-slit group dividing plate 3 is located at the focal plane of the collimating objective lens 6; the positioning light spot light is reflected by the right-angle prism 4 and the beam splitter prism 5, and then emitted from the collimating objective lens 6 to irradiate the reflector to be measured 7; the light emitted from the collimating objective lens 6 is reflected by the reflector to be measured 7 and then returns to the autocollimator, and is focused on the photosensitive surface of the planar array image detector 8 after passing through the collimating objective lens 6 and the beam splitter prism 5 in sequence.

[0054] In the embodiment, the light source 1 is a high-performance LED, which is fixed on a quartz base with ultraviolet glue; the focusing lens 2 is an aspherical focusing lens with a scattering plane, which is fixed on a quartz base with ultraviolet glue; the orthogonal cross multi-slit group dividing plate 3, the right-angle prism 4, and the splitter prism 5 are glued into a whole with ultraviolet glue, which improves the overall stability; the collimating objective lens 6 is a 2-inch achromatic lens with a focal length of f=300mm.

[0055] The structure design of the reticle of the orthogonal cross multi-slit group is as follows Figure 4 As shown, the centers of 10 horizontal slits and 10 vertical slits are aligned; the parallel light emitted by the focusing lens 2 will form a cross-shaped positioning light spot of the same shape after passing through the slits. The slit width, length and number can be adjusted according to different measurement ranges, different measurement accuracy requirements and corresponding area array sensor pixel sizes.

[0056] Taking into account performance indicators and other factors, the high-resolution area array sensor selected in the embodiment is a 1-inch 4-megapixel CMOS black-and-white image sensor with an effective pixel array of 2048×2048 and a pixel size of 5.5μm. It has the advantages of high resolution, high transmission rate, good imaging quality, and low power consumption. It is compatible with the USB3 Vision protocol and the GenICam standard and has good versatility. Compared with the dual-line array sensor, the single area array sensor has a simple structure and good stability.

[0057] The area array image detector 8 is used to image the positioning light spot. The actual imaging of the designed orthogonal cross multi-slit group dividing plate 3 on the area array image detector 8 is as follows: Figure 5As shown; through the high-precision image positioning algorithm and data processing program, the grayscale values ​​of each pixel of the area array image detector 8 are averaged by row and column, and the two-dimensional image information is converted into two one-dimensional image signals. The 2048-row image is compared with the linear array CCD single-row image, and the measurement resolution can be improved by √2048≈45 times in theory; each signal peak of the one-dimensional image signal corresponding to the row and column average values ​​is individually located and averaged. The average of 10 peaks is relative to a single peak, and the measurement resolution can also be improved by √10≈3 times in theory; through two averages, the image positioning accuracy of the positioning spot can be improved by about 135 times compared to a single-slit single-row image, thereby improving the measurement resolution and stability of the autocollimator device; according to the principle of optical autocollimation, the deflection angles of the reflector 7 to be measured in the x and y directions can be calculated from the position offset of the positioning spot; according to the geometric relationship, for the image averaged by column, the measured image is as follows Figure 6 As shown, its displacement reflects the deflection of the reflector 7 to be measured in the x direction. For the image averaged by line, its displacement reflects the deflection of the reflector 7 to be measured in the y direction. The high-precision image positioning algorithm and data processing program are installed in the host computer.

[0058] Furthermore, the relationship between the deflection angles in the x and y directions of the reflector 7 to be measured and the position change of the positioning spot is:

[0059] θx=Δdx / 2f

[0060] θy=Δdy / 2f

[0061] Wherein, Δdx and Δdy are the relative displacements of the positioning light spot on the area array sensor 8 , and f is the focal length of the collimating objective lens 6 .

[0062] The housing 9 is mainly used to shield the stray light from the external environment, reduce the influence of the measurement environment temperature, airflow, etc. on the measurement optical path, prevent dust from entering the instrument, and improve the stability of the measurement.

[0063] Embodiment 3:

[0064] The other structures of this embodiment are the same as those of embodiment 2, except that the USB data interface reserved in the device can be connected to various devices such as industrial computers and notebooks, which is convenient for subsequent analysis and processing of measurement data and expands the application scenarios of the autocollimator. The image acquisition system and data processing module can add various calculation modules as needed to realize various measurement functions such as flatness and verticality, and expand the use scenarios.

[0065] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An autocollimator device based on an orthogonal cross multi-slit group, characterized in that: The invention comprises a light source (1), a focusing lens (2), an orthogonal cross multi-slit group dividing plate (3), a right-angle prism (4), a beam splitter (5), a collimating objective lens (6), a reflector to be measured (7), and a planar array image detector (8); the light source (1) is located at the focus of the focusing lens (2); the divergent light beam of the light source (1) is converged by the focusing lens (2) and uniformly illuminates the orthogonal cross multi-slit group dividing plate (3) to form a positioning light spot; the orthogonal cross multi-slit group dividing plate (3) is located at the focal plane of the collimating objective lens (6); the orthogonal cross multi-slit group dividing plate (3) has a plurality of mutually perpendicular horizontal slits and a plurality of vertical slits, forming a light spot composed of a plurality of slits. The invention relates to an orthogonal cross positioning image composed of two slits; the positioning light spot light is reflected by the right-angle prism (4) and the beam splitter (5) and then emitted from the collimating objective lens (6) to irradiate the reflector (7) to be measured; the light emitted by the collimating objective lens (6) is reflected by the reflector (7) to be measured and then returned, and is focused on the photosensitive surface of the area array image detector (8) after passing through the collimating objective lens (6) and the beam splitter (5) in sequence; the area array image detector (8) is used to image the positioning light spot and realize high-precision monitoring of the position change of the positioning light spot image; according to the principle of optical self-collimation, the deflection angle of the reflector (7) to be measured in the x-axis and y-axis directions is calculated from the position offset of the positioning light spot.

2. The autocollimator device based on an orthogonal cross multi-slit group according to claim 1, characterized in that: The light at each point of the orthogonal cross multi-slit group dividing plate (3) passes through the beam splitter prism (5) and the collimating lens (6) in sequence to form parallel light output; the parallel light reflected back by the reflector to be measured (7) passes through the collimating lens (6) and is focused on the photosensitive surface of the area array image detector (8); the beam splitter prism (5) is used to change the propagation direction of the light so as to separate the output light of the collimating lens (6) from the incident light.

3. The autocollimator device based on an orthogonal cross multi-slit group according to claim 2, characterized in that: The orthogonal cross multi-slit group dividing plate (3) and the photosensitive surface of the area array image detector (8) are both placed at the conjugate focal plane of the collimating objective lens (6).

4. The autocollimator device based on an orthogonal cross multi-slit group according to claim 2, characterized in that: The focusing lens (2) is an aspherical condensing lens with a scattering plane.

5. The autocollimator device based on an orthogonal cross multi-slit group according to claim 3, characterized in that: The image sensor of the area array image detector (8) is a metal oxide semiconductor sensor or a charge coupled device sensor; the area array image detector (8) realizes real-time image display of the positioning light spot; the grayscale values ​​of each pixel of the area array image detector (8) are averaged in rows and columns respectively, and according to the geometric relationship, the displacement of the image after the column average represents the deflection angle of the reflector (7) to be measured in the x direction, and the displacement of the image after the row average represents the deflection angle of the reflector (7) to be measured in the y direction.

6. The autocollimator device based on an orthogonal cross multi-slit group according to claim 5, characterized in that: The area array image detector (8) uses a high-precision image positioning algorithm to monitor the position change of two one-dimensional images averaged by row and column, and converts the change of the positioning light spot position into the deflection angle of the reflector (7) to be measured based on the optical self-collimation principle; an angle measurement program based on the high-precision image positioning algorithm is installed in the host computer, and the image formed by the positioning light spot and the angle measurement result can be displayed in real time on the display interface.

7. The autocollimator device based on an orthogonal cross multi-slit group according to any one of claims 1 to 6, characterized in that: When the reflector (7) to be measured is perpendicular to the optical axis of the autocollimator device, the corresponding angle measurement value is zero, the deflection angle of the reflector (7) to be measured takes this as the absolute reference zero point, and the angle measurement value is the deflection angle relative to the absolute zero point.

8. The autocollimator device based on an orthogonal cross multi-slit group according to claim 7, characterized in that: The deflection angles of the reflector (7) to be measured in the x and y directions are: Where, Δd x , Δd y is the relative displacement of the one-dimensional image position after averaging by column and row, and f is the focal length of the collimating objective lens.

9. The autocollimator device based on an orthogonal cross multi-slit group according to claim 7, characterized in that: The light intensity stability of the light source (1) is controlled by feedback of the grayscale value of the pixel of the area array image detector (8), so as to enhance the stability of the device.

Images