Angle measuring method and angle measuring device

Abstract

The invention relates to an angle measurement method and an angle measurement device. The angle measurement method comprises the following steps: aligning a first object and a second object in a first direction according to a first positioning pattern and a second positioning pattern; and calculating a rotation angle between the first object and the second object according to the first measurement pattern and the second measurement pattern. According to the angle measurement method provided by the invention, through the design that the positioning pattern is matched with the measurement pattern, the measurement mark has a higher capture range, so that the situation that the visual field needs to be explored and searched is greatly reduced while high-precision measurement is kept, and the detection efficiency of the rotation angle between the first object and the second object is improved. Meanwhile, the anti-shielding design enables deviation to be measured and calculated even if shielding occurs, so that the number of times of motion iteration is reduced, and the detection efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of optical measurement, specifically to an angle measurement method and an angle measurement device. Background Technology

[0002] In precision automation fields such as semiconductor manufacturing, medical robotic surgery, and scientific research, which require micro- and nano-scale alignment and measurement of small angles, as well as in position feedback systems of some nanopiezoelectric motion systems, the marking patterns used to measure angles are often complex, have a small capture range, and require multiple explorations to mark the field of view. Summary of the Invention

[0003] This application provides an angle measurement method, which includes: acquiring a first marking pattern on a first object and a second marking pattern on a second object to form a detection pattern, wherein the first marking pattern includes a first positioning pattern and a first measurement pattern, and the second marking pattern includes a second positioning pattern and a second measurement pattern; aligning the first object and the second object in a first direction according to the first positioning pattern and the second positioning pattern; aligning the first object and the second object in a second direction according to the first measurement pattern and the second measurement pattern; and calculating the rotation angle between the first object and the second object according to the first measurement pattern and the second measurement pattern.

[0004] According to an embodiment of this application, the detection pattern includes a first detection pattern and a second detection pattern. The first object has two first mark patterns, the positions of which are symmetrically distributed about the rotation center of the first object. The second object has two second mark patterns, the positions of which are symmetrically distributed about the rotation center of the second object. The two first mark patterns and the two second mark patterns correspond one-to-one and form the first detection pattern and the second detection pattern. The step of aligning the first object and the second object in a second direction according to the first measurement pattern and the second measurement pattern includes: obtaining a first displacement difference between the first measurement pattern and the second measurement pattern of the first detection pattern in the second direction, and obtaining a second displacement difference between the first measurement pattern and the second measurement pattern of the second detection pattern in the second direction; aligning the first object and the second object in the second direction according to the first displacement difference and the second displacement difference.

[0005] According to an embodiment of this application, the step of calculating the rotation angle between the first object and the second object based on the first measurement pattern and the second measurement pattern includes: obtaining the displacement difference between the first measurement pattern and the second measurement pattern in the second direction; calculating the rotation angle based on the displacement difference; wherein the first direction and the second direction are perpendicular.

[0006] According to an embodiment of this application, the step of obtaining the displacement difference between the first measurement pattern and the second measurement pattern in a second direction includes: obtaining moiré fringes formed by the first measurement pattern and the second measurement pattern; and calculating the displacement difference based on the moiré fringes.

[0007] According to one embodiment of this application, the first measurement pattern includes a plurality of first test strips arranged in parallel intervals, and a first convex strip is provided in the middle of the plurality of first test strips; the second measurement pattern includes a plurality of second test strips arranged in parallel intervals, and a second convex strip is provided in the middle of the plurality of second test strips; the step of calculating the displacement difference based on the moiré fringes includes: obtaining a first difference value based on the positional relationship between the first convex strip and the second convex strip; obtaining a second difference value based on the moiré fringes; and calculating the displacement difference by combining the first difference value and the second difference value.

[0008] According to one embodiment of this application, the first positioning pattern includes a first positioning block and a second positioning block located on both sides of the first measuring pattern, and the second positioning pattern includes a third positioning block and a fourth positioning block located on both sides of the second measuring pattern; the first positioning block and the third positioning block are configured such that, during the relative movement of the first object and the second object, the first positioning block does not overlap with the third positioning block at least partially, and the third positioning block does not overlap with the first positioning block at least partially; the second positioning block and the fourth positioning block are configured such that, during the relative movement of the first object and the second object, the second positioning block does not overlap with the fourth positioning block at least partially, and the fourth positioning block does not overlap with the second positioning block at least partially.

[0009] According to one embodiment of this application, both the first positioning pattern and the second positioning pattern are provided with a positioning strip and an anti-obstruction strip. The positioning strip and the anti-obstruction strip of the first positioning pattern are parallel, and the positioning strip and the anti-obstruction strip of the second positioning pattern are parallel. The length of the anti-obstruction strip is less than the length of the positioning strip.

[0010] According to one embodiment of this application, the first positioning block includes a first positioning strip, the second positioning block includes a second positioning strip symmetrically distributed with the first positioning strip, the third positioning block includes a third positioning strip, and the fourth positioning block includes a fourth positioning strip symmetrically distributed with the third positioning strip; the step of aligning the first object and the second object in a first direction according to the first positioning pattern and the second positioning pattern includes: aligning the axis of symmetry between the first positioning strip and the second positioning strip and the axis of symmetry between the third positioning strip and the fourth positioning strip.

[0011] This application embodiment also provides an angle measuring device, which uses the angle measuring method described in the above embodiment to measure the rotation angle between the first object and the second object.

[0012] According to one embodiment of this application, the angle measuring device includes a detector, which includes a first detector and a second detector. The first detector is used to acquire a first detection pattern, and the second detector is used to acquire a second detection pattern. A second object is located between the first object and the detector. A lens assembly is provided between the first object and the second object. The lens assembly is used to project the first marking pattern on the first object, so that the first marking pattern and the second marking pattern form the first detection pattern and the second detection pattern.

[0013] The angle measurement method and angle measurement device provided in this application perform displacement positioning only in the first direction, and positioning and angle measurement simultaneously in the second direction. The design of the positioning pattern and the measurement pattern in combination improves the detection efficiency and accuracy of the rotation angle between the first object and the second object. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of one embodiment of the detection pattern of this application; Figure 2 This is a schematic diagram of another embodiment of the detection pattern of this application; Figure 3 This is a schematic diagram of yet another embodiment of the detection pattern of this application; Figure 4 This is a schematic diagram of another embodiment of the detection pattern of this application; Figure 5 This is a schematic diagram of the structure of an embodiment of the angle measuring device of this application; Figure 6 This is a flowchart illustrating an embodiment of the angle measurement method of this application; Figure 7 yes Figure 6 A flowchart illustrating an embodiment of step S300 of the angle measurement method shown; Figure 8 yes Figure 6 A flowchart illustrating an embodiment of step S400 of the angle measurement method shown; Figure 9 yes Figure 8 A flowchart illustrating an embodiment of step S410 of the angle measurement method shown. Figure 10 yes Figure 9 The flowchart of step S412 of the angle measurement method shown is a schematic diagram of an embodiment. Detailed Implementation

[0016] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0017] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0018] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0019] This application provides an angle measurement method, such as... Figure 1 , Figure 5 and Figure 6 As shown, angle measurement methods include: Step S100: Obtain the first marking pattern 211 on the first object 210 and the second marking pattern 221 on the second object 220 to form a detection pattern 10, wherein the first marking pattern 211 includes a first positioning pattern 110 and a first measurement pattern 120, and the second marking pattern 221 includes a second positioning pattern 130 and a second measurement pattern 140.

[0020] In some embodiments, the first object 210 and the second object 220 may be a photomask and a silicon wafer, respectively, or the first object 210 and the second object 220 may also be wafers. The first marking pattern 211 and the second marking pattern 221 may be printed on the first object 210 and the second object 220 by means of engraving, or they may be sputtered on the first object 210 and the second object 220 by means of sputtering. This application does not make specific limitations.

[0021] In some embodiments, the first object 210 and the second object 220 may be plate-like structures, and the shapes of the first object 210 and the second object 220 may be circular, square, polygonal, or the like.

[0022] Step S200: Align the first object 210 and the second object 220 in the first direction X according to the first positioning pattern 110 and the second positioning pattern 130.

[0023] In some embodiments, the first object 210 and the second object 220 can be aligned by moving their relative positions in the first direction X, so that the rotation centers of the first object 210 and the second object 220 are aligned in the first direction X. Specifically, the relative positions of the first object 210 and the second object 220 can be adjusted by devices such as a robotic arm or a precision displacement stage.

[0024] Step S300: Align the first object 210 and the second object 220 in the second direction Y according to the first measurement pattern 120 and the second measurement pattern 140.

[0025] In some embodiments, the first object 210 and the second object 220 can be aligned by moving their relative positions in the second direction Y, so that the rotation center of the first object 210 and the rotation center of the second object 220 are aligned in the second direction Y.

[0026] Step S400: Calculate the rotation angle θ between the first object 210 and the second object 220 based on the first measurement pattern 120 and the second measurement pattern 140.

[0027] In some embodiments, as shown in 4, the angle measurement method of this application can be applied to the semiconductor manufacturing field. The angle measurement method can measure the rotation angle θ of the positioning notch of the wafer to align the wafer.

[0028] The angle measurement method of this application only performs displacement positioning in the first direction X, and simultaneously performs displacement positioning and angle measurement in the second direction Y. The different positioning and measurement requirements in different directions mean that only symmetrical zeroing is needed in the first direction X, without requiring a large precision measurement range, while a sufficient precision measurement range is required in the second direction Y to ensure that the rotation angle θ can be measured correctly. The design of the positioning pattern and the measurement pattern in combination is beneficial to improving measurement efficiency and accuracy. Simultaneously, the positioning and angle measurement of the first object 210 and the second object 220 are concentrated on the detection pattern 10. The detection pattern 10 can simultaneously solve lateral alignment and longitudinal measurement, and its symmetrical and compact arrangement ensures that the positions of the positioning pattern and the measurement pattern are unified, occupying a smaller area than the case of symmetrical drawing with two independent marks in different directions, thus having a higher capture range and saving operation time.

[0029] In some embodiments, the angle measurement method can be applied to the alignment of the first object 210 and the second object 220. For example, the angle measurement method can be applied to wafer alignment. After obtaining the rotation angle θ between the first object 210 and the second object 220, the first object 210 and / or the second object 220 can be rotated according to the rotation angle θ so that the first object 210 and the second object 220 are aligned in the circumferential direction.

[0030] In some embodiments, such as Figure 4 As shown, the detection pattern 10 includes a first detection pattern 170 and a second detection pattern 180. The first object 210 is provided with two first mark patterns 211, and the positions of the two first mark patterns 211 are symmetrically distributed with respect to the rotation center of the first object 210. The second object 220 is provided with two second mark patterns 221, and the positions of the two second mark patterns 221 are symmetrically distributed with respect to the rotation center of the second object 220. The two first mark patterns 211 and the two second mark patterns 221 correspond one-to-one and form the first detection pattern 170 and the second detection pattern 180.

[0031] In some embodiments, such as Figure 7 As shown, step S300 includes: Step S310: Obtain the first displacement difference a in the second direction Y of the first measurement pattern 120 and the second measurement pattern 140 of the first detection pattern 170, and obtain the second displacement difference b in the second direction Y of the first measurement pattern 120 and the second measurement pattern 140 of the second detection pattern 180. Step S320: Align the first object 210 and the second object 220 in the second direction Y according to the first displacement difference a and the second displacement difference b.

[0032] In some embodiments, when the first positioning pattern 110 and the second positioning pattern 130 of the first detection pattern 170 are aligned in the first direction X, the first positioning pattern 110 and the second positioning pattern 130 of the second detection pattern 180 are also aligned in the first direction X. At this time, the rotation center of the first object 210 and the rotation center of the second object 220 are aligned in the first direction X.

[0033] In some embodiments, the first displacement difference a and the second displacement difference b have opposite signs. By adjusting the relative positions of the first object 210 and the second object 220 in the second direction Y, the magnitudes of the first displacement difference a and the second displacement difference b can be changed. When the sum of the first displacement difference a and the second displacement difference b is 0, it indicates that the rotation center of the first object 210 and the rotation center of the second object 220 are aligned in the second direction Y. Combined with step S200, the rotation center of the first object 210 and the rotation center of the second object 220 are aligned at this time.

[0034] In some embodiments, such as Figure 8 As shown, step S400 includes: Step S410: Obtain the displacement difference between the first measurement pattern 120 and the second measurement pattern 140 in the second direction Y.

[0035] Step S420: Calculate the rotation angle θ based on the displacement difference.

[0036] In some embodiments, the first direction X and the second direction Y are perpendicular. In some embodiments, the first direction X is a horizontal direction and the second direction Y is a vertical direction. In some other embodiments, the first direction X and the second direction Y may also be two directions perpendicular to each other on a horizontal plane.

[0037] In some embodiments, the first direction X and the second direction Y are approximately perpendicular, and the angle between the first direction X and the second direction Y is in the range of 85° to 95°. Specifically, the angle between the first direction X and the second direction Y is 85°, 90.1°, 89.9°, 95° and any value between the above angles.

[0038] In some embodiments, the first object 210 and the second object 220 can be translated relative to each other to align in the first direction X and the second direction Y. This translation aligns the positions of the first object 210 and the second object 220, but with a certain rotation angle θ relative to each other. The rotation angle θ can be accurately measured based on the first measurement pattern 120 and the second measurement pattern 140. The displacement difference between the first measurement pattern 120 and the second measurement pattern 140 in the second direction Y is positively correlated with the magnitude of the rotation angle θ. When the rotation angle θ is 0, the displacement difference between the first measurement pattern 120 and the second measurement pattern 140 in the second direction Y is 0, and at this time, the first object 210 and the second object 220 are aligned in the circumferential direction. When the rotation angle θ is not 0, the displacement difference is also not 0, and the rotation angle θ can be calculated from the displacement difference.

[0039] In some embodiments, the trigonometric function of the rotation angle θ can be obtained based on the distance between the detection pattern 10 and the rotation axis of the first object 210 and the displacement difference, and the rotation angle θ can be obtained based on the trigonometric function.

[0040] In some embodiments, the rotation angle θ between the first object 210 and the second object 220 is a small angle. Therefore, the value of the displacement difference can be directly taken as an approximation of the magnitude of the rotation angle θ.

[0041] In some embodiments, step S410 includes: subtracting the first displacement difference a and the second displacement difference b and taking the average to obtain the displacement difference.

[0042] In some embodiments, due to the existence of errors, the absolute values ​​of the first displacement difference a and the second displacement difference b are not necessarily equal. The measurement error can be reduced by combining the calculation of the first displacement difference a and the second displacement difference b.

[0043] In some other embodiments, the number of detection patterns 10 may be one or more. For example, the detection pattern 10 may also include a third detection pattern, a fourth detection pattern, etc. The average value of the rotation angle θ measured by multiple detection patterns 10 can be used to obtain the final rotation angle θ, so as to reduce the error.

[0044] In some embodiments, such as Figure 9 As shown, step S410 includes: Step S411: Obtain the moiré fringes formed by the first measurement pattern 120 and the second measurement pattern 140.

[0045] Moiré patterns, also known as water ripple patterns, are macroscopic wavy patterns formed by combinations of periodic structures with minute differences. Because their macroscopic wavy patterns can reflect information about microscopic differences, they have a signal amplification effect and are widely used in many fields, such as medicine, photolithography, electron microscopy, measurement of stress and strain in periodic structures, measurement of small-angle stacking of two-dimensional materials, and high-precision alignment in the semiconductor industry.

[0046] Step S412: Calculate the displacement difference based on the moiré fringes.

[0047] In some embodiments, when the first object 210 and the second object 220 are aligned in the first direction X, the first measurement pattern 120 and the second measurement pattern 140 form moiré fringes, and the displacement difference in the second direction Y can be accurately measured by the formed moiré fringes.

[0048] In some embodiments, such as Figure 2 As shown, the first measurement pattern 120 includes a plurality of first test strips 121 arranged in parallel at intervals, and a first protrusion 122 protruding from the middle of the plurality of first test strips 121; the second measurement pattern 140 includes a plurality of second test strips 141 arranged in parallel at intervals, and a second protrusion 142 protruding from the middle of the second test strips 141. The extension direction of the first test strips 121 and the first protrusion 122 is a first direction X, or approximately the first direction X, and the extension direction of the second test strips 141 and the second protrusion 142 is a first direction X, or approximately the first direction X.

[0049] In some embodiments, such as Figure 10 As shown, step S412 includes: Step S4121: Obtain the first difference value based on the positional relationship between the first protrusion 122 and the second protrusion 142.

[0050] Step S4122: Obtain the second difference based on the moiré fringes.

[0051] Step S4123: Calculate the displacement difference by combining the first difference and the second difference.

[0052] In some embodiments, when the rotation angle θ is 0, the first protrusion 122 is aligned with the second protrusion 142. When the rotation angle θ is not 0, the distance difference between the first protrusion 122 and the second protrusion 142 in the second direction Y can be used as a first difference value to coarsely measure the displacement difference between the first measurement pattern 120 and the second measurement pattern 140 in the second direction Y. The moiré fringes formed by the first measurement pattern 120 and the second measurement pattern 140 can be finely measured to obtain a second difference value. The first difference value plus the second difference value can obtain a more accurate displacement difference. Specifically, the first measurement pattern 120 and the second measurement pattern 140 are composed of verniers. The periodicity of the vernier lines forms moiré fringes with the camera pixel array. The center of the vernier has a certain lateral displacement compared to other parts, i.e., displacement in the first direction X, to represent the coarse measurement portion of the center position of the first measurement pattern 120 and the second measurement pattern 140. The fine measurement portion of the center position of the first measurement pattern 120 and the second measurement pattern 140 is given by the position of the moiré fringes. The sum of the coarse measurement portion and the fine measurement portion is the longitudinal displacement of the center position of the first measurement pattern 120 and the second measurement pattern 140, i.e., displacement in the second direction Y. The first measurement pattern 120 and the second measurement pattern 140 can quickly and accurately measure the displacement difference by combining coarse and fine measurements.

[0053] In some other embodiments, the displacement difference can also be calculated based on the number of stripes spaced between the first measurement pattern 120 and the second measurement pattern 140.

[0054] In some embodiments, the step of aligning the first object 210 and the second object 220 in the first direction X according to the first positioning pattern 110 and the second positioning pattern 130 may include: aligning the first positioning pattern 110 along the axis of symmetry of the second direction Y and the second positioning pattern 130 along the axis of symmetry of the second direction Y.

[0055] In some embodiments, such as Figure 1 As shown, the first positioning pattern 110 includes a first positioning block 111 and a second positioning block 112 located on both sides of the first measuring pattern 120, and the second positioning pattern 130 includes a third positioning block 131 and a fourth positioning block 132 located on both sides of the second measuring pattern 140. When the first object 210 and the second object 220 are aligned in the first direction X, the first marking pattern 211 and the second marking pattern 221 intersect, the third positioning block 131 is located between the first positioning block 111 and the first measuring pattern 120, the fourth positioning block 132 is located between the second positioning block 112 and the second measuring pattern 140, and the first measuring pattern 120 is close to the second measuring pattern 140.

[0056] In some embodiments, when the first object 210 and the second object 220 are aligned in the first direction X, the first positioning block 111, the third positioning block 131, the first measuring pattern 120, the second measuring pattern 140, the fourth positioning block 132, and the second positioning block 112 are arranged sequentially along the first direction X.

[0057] In some embodiments, such as Figure 2 As shown, the first positioning block 111 includes a first positioning strip 1111, the second positioning block 112 includes a second positioning strip 1121 that is symmetrically distributed with the first positioning strip 1111, the third positioning block 131 includes a third positioning strip 1311, and the fourth positioning block 132 includes a fourth positioning strip 1321 that is symmetrically distributed with the third positioning strip 1311.

[0058] In some embodiments, the extension direction of the first test strip 121 is perpendicular to the extension direction of the first positioning strip 1111; the extension direction of the second test strip 141 is perpendicular to the extension direction of the second positioning strip 1121. In some other embodiments, the included angle between the first test strip 121 and the first positioning strip 1111 can be 80°~100°, and the included angle between the second test strip 141 and the second positioning strip 1121 can be 80°~100°.

[0059] In some embodiments, the extension directions of the first positioning bar 1111 and the third positioning bar 1311 are both the second direction Y, or approximately the second direction Y.

[0060] In some embodiments, step S200 includes aligning the axis of symmetry between the first positioning bar 1111 and the second positioning bar 1121 and the axis of symmetry between the third positioning bar 1311 and the fourth positioning bar 1321.

[0061] In some embodiments, the relative positions of the first object 210 and the second object 220 in the first direction X can be adjusted, thereby adjusting the relative positions of the two axes of symmetry. When the two axes of symmetry are approximately aligned, the first object 210 and the second object 220 are aligned in the first direction X.

[0062] This application adopts different graphic measurement principles in the first direction X and the second direction Y, so that the detection pattern 10 has a strong zero indication and a short lateral width in the first direction X, while ensuring that it has a large precision measurement range in the second direction Y, so as to adapt to the situation of small angle measurement.

[0063] In some embodiments, since the alignment of the two lateral nulling patterns, the first positioning pattern 110 and the second positioning pattern 130, is established by symmetry in the lateral (first direction X) position, even if linewidth fluctuations occur due to processing during micromachining, the center position can be indicated more accurately. Moreover, only longer double lines are used, without the need for periodic patterns, making the total width short enough to satisfy a sufficient capture range in a limited imaging field of view. While the longitudinal (second direction Y) direction has a longer total height due to the use of vernier measurement, it can operate at a non-zero point, which is suitable for small corners. After combining the two positioning patterns, the first positioning pattern 110 and the second positioning pattern 130, and the two measurement patterns, the first measurement pattern 120 and the second measurement pattern 140, the overall size of the detection pattern 10 is basically square, resulting in a large capture range in the camera's field of view with a balanced aspect ratio, so that the camera can capture the detection pattern 10.

[0064] In some embodiments, when there is a rotation angle θ between the first object 210 and the second object 220, since the rotation angle θ is a small angle, when the axis of symmetry between the first positioning strip 1111 and the second positioning strip 1121 and the axis of symmetry between the third positioning strip 1311 and the fourth positioning strip 1321 are aligned, the error in the alignment of the two axes of symmetry is a second-order small amount compared to the rotation angle θ, and can be ignored.

[0065] In some embodiments, such as Figure 1 and Figure 3 As shown, the first positioning block 111 and the third positioning block 131 are configured such that, during the relative movement of the first object 210 and the second object 220, the first positioning block 111 does not overlap with the third positioning block 131 at least partially, and the third positioning block 131 does not overlap with the first positioning block 111 at least partially; the second positioning block 112 and the fourth positioning block 132 are configured such that, during the relative movement of the first object 210 and the second object 220, the second positioning block 112 does not overlap with the fourth positioning block 132 at least partially, and the fourth positioning block 132 does not overlap with the second positioning block 112 at least partially.

[0066] In some embodiments, the first marking pattern 211 and the second marking pattern 221 have similar shapes. The anti-obstruction design between the first positioning block 111 and the third positioning block 131, and between the second positioning block 112 and the fourth positioning block 132, can prevent the first object 210 and the second object 220 from obstructing each other during relative movement, so as to facilitate the confirmation of the positions of the first positioning pattern 110 and the second positioning pattern 130. For example, if the positions of the first positioning block 111 and the third positioning block 131 coincide, the shape of their combination will inevitably be different from the shape of either the first positioning block 111 or the third positioning block 131. Therefore, it can be immediately determined that the positions of the two coincide, and the first object 210 and the second object 220 can be moved.

[0067] In some embodiments, the first marking pattern 211 and the second marking pattern 221 are different colors to facilitate identification; for example, the first marking pattern 211 may be orange and the second marking pattern 221 may be brown. In some other embodiments, the first marking pattern 211 and the second marking pattern 221 may be the same color.

[0068] In some embodiments, both the first positioning pattern 110 and the second positioning pattern 130 are provided with a positioning strip 150 and an anti-obstruction strip 160. The positioning strip 150 and the anti-obstruction strip 160 of the first positioning pattern 110 are parallel, and the positioning strip 150 and the anti-obstruction strip 160 of the second positioning pattern 130 are parallel. The length of the anti-obstruction strip 160 is less than the length of the positioning strip 150. The positioning strip 150 can be used to align the first object 210 and the second object 220 in the first direction X. The anti-obstruction strip 160 can be used to prevent the first positioning pattern 110 and the second positioning pattern 130 from completely obscuring each other, so as to show the position of the first marking pattern 211 and the second marking pattern 221.

[0069] In some embodiments, the positioning strip 150 includes a first positioning strip 1111, a second positioning strip 1121, a third positioning strip 1311 and a fourth positioning strip 1321, and the anti-obstruction strip 160 includes a first anti-obstruction strip 1112, a second anti-obstruction strip 1122, a third anti-obstruction strip 1312 and a fourth anti-obstruction strip 1322. The detection pattern 10 has a first end 190 and a second end 191 arranged opposite to each other along the second direction Y. The lengths of the first positioning strip 1111, the second positioning strip 1121, the third positioning strip 1311 and the fourth positioning strip 1321 are all equal. The first positioning block 111 includes a first anti-obstruction strip 1112 parallel to the first positioning strip 1111. The second positioning block 112 includes a second anti-obstruction strip 1122 parallel to the second positioning strip 1121. The third positioning block 131 includes a third anti-obstruction strip 1312 parallel to the third positioning strip 1311. The fourth positioning block 132 includes a fourth anti-obstruction strip 1322 parallel to the fourth positioning strip 1321. The lengths of the first anti-obstruction strip 1112, the second anti-obstruction strip 1122, the third anti-obstruction strip 1312 and the fourth anti-obstruction strip 1322 are all equal and less than the length of the first positioning strip 1111.

[0070] In some embodiments, the ends of the first positioning strip 1111 and the second anti-obstruction strip 1122 near the second end 191 are flush; the ends of the second positioning strip 1121 and the second anti-obstruction strip 1122 near the first end 190 are flush; the ends of the third positioning strip 1311 and the third anti-obstruction strip 1312 near the first end 190 are flush; and the ends of the fourth positioning strip 1321 and the fourth anti-obstruction strip 1322 near the second end 191 are flush. One end of the anti-obstruction strip 160 is shorter than that of the positioning strip 150, and the shorter ends of two adjacent anti-obstruction strips 160 are staggered to form an anti-obstruction design. This design can display the positions of the first positioning pattern 110 and the second positioning pattern 130 when obstruction occurs, prompting the corresponding actuator to complete the alignment movement.

[0071] In some embodiments, such as Figure 3 As shown, regardless of the positional relationship between the first positioning pattern 110 and the second positioning pattern 130, at least one of the adjacent positioning strips 150 and anti-occlusion strips 160 will not be completely obscured. For example, at least one of the two protruding points, the first protruding point 1113 of the first positioning strip 1111 near the first end 190 and the second protruding point 1114 of the first anti-occlusion strip 1112 near the second end 191, will protrude and not be obscured by the third positioning block 131. This allows the overlap between the first positioning block 111 and the third positioning block 131 to be identified, and the direction and distance to be moved in the next step of alignment can be estimated. This anti-occlusion design effectively saves the number of alignment iterations, significantly reducing the alignment time required when the initial state is poor.

[0072] This application embodiment also provides an angle measuring device 20, such as Figure 5 As shown, the angle measuring device 20 uses the angle measuring method in the above embodiment to measure the rotation angle θ between the first object 210 and the second object 220.

[0073] In some embodiments, the angle measuring device 20 includes a detector 230, which includes a first detector 231 and a second detector 232. The first detector 231 is used to acquire a first detection pattern 170, and the second detector 232 is used to acquire a second detection pattern 180. A second object 220 is located between the first object 210 and the detector 230. A lens assembly 240 is provided between the first object 210 and the second object 220. The lens assembly 240 is used to project a first marking pattern 211 on the first object 210, so that the first marking pattern 211 and the second marking pattern 221 form the first detection pattern 170 and the second detection pattern 180.

[0074] In some other embodiments, the number of detectors 230 may also be one, with a single detector 230 simultaneously receiving the first detection pattern 170 and the second detection pattern 180.

[0075] In some embodiments, the detector 230 is a photosensitive detector (such as a camera), and the second object 220 is provided with optical devices such as a grating or a mask. The grating is provided with a second marking pattern 221. Light emitted from the first marking pattern 211 of the first object 210 can be projected onto the grating of the second object 220 through the lens assembly 240 to form a detection pattern 10 with the first marking pattern 211 and the second marking pattern 221. The detector 230 receives the detection pattern 10 and further analyzes it. The precision measurement range of the second direction Y in this application is determined by the number of grating periods and the grating linewidth of the longitudinal markings. Combined with moiré fringe technology, it can satisfy both a large precision measurement range and high measurement accuracy.

[0076] In some embodiments, the first object 210 is provided with a grating, the grating of the first object 210 is provided with a first marking pattern 211, and light passes through the grating of the first object 210 and the grating of the second object 220 to form a detection pattern 10.

[0077] In some embodiments, the lens assembly 240 includes a first lens 241 and a second lens 242, wherein the first lens 241 is located between the second lens 242 and the first object 210, and both the first lens 241 and the second lens 242 are convex lenses. The lens assembly 240 is used to project a first marking pattern 211 of the first object 210 onto a position corresponding to a second marking pattern 221 of the second object 220.

[0078] In some embodiments, the first marking pattern 211 and the second marking pattern 221 are mutually conjugate in the optical imaging system of the lens assembly 240, and both are obtained and analyzed by the detector 230 to determine their relative positions. The first object 210 has two first marking patterns 211, namely the first pattern 2111 and the second pattern 2112, and the second object 220 has two second marking patterns 221, namely the third pattern 2211 and the fourth pattern 2212. The lens assembly 240 can project the first pattern 2111 located on the left to the third pattern 2211 located on the right to form the first detection pattern 170, and simultaneously project the second pattern 2112 located on the right to the fourth pattern 2212 located on the left to form the second detection pattern 180.

[0079] In some embodiments, the size of the first object 210 is the same as the size of the second object 220, and the distance between the first pattern 2111 and the second pattern 2112 can be equal to the distance between the third pattern 2211 and the fourth pattern 2212.

[0080] In some embodiments, the size of the first object 210 and the size of the second object 220 may be different. For example, the size of the first object 210 is larger than the size of the second object 220, and the distance between the first pattern 2111 and the second pattern 2112 is greater than the distance between the third pattern 2211 and the fourth pattern 2212. Using the lens assembly 240, the first marking pattern 211 can be accurately projected onto the second marking pattern 221.

[0081] The angle measurement method and angle measurement device 20 provided in this application adopt different graphic measurement principles in the first direction X and the second direction Y, and form an anti-obstruction design by setting an anti-obstruction strip 160, which improves the detection efficiency of angle measurement and can meet both the large precision measurement range and high measurement accuracy.

[0082] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. Any equivalent device or equivalent process transformation made based on the content of this application specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this application.

Claims

1. An angle measurement method, characterized in that, The angle measurement method includes: A detection pattern is formed by acquiring a first marking pattern on a first object and a second marking pattern on a second object, wherein the first marking pattern includes a first positioning pattern and a first measurement pattern, and the second marking pattern includes a second positioning pattern and a second measurement pattern; The first object and the second object are aligned in a first direction according to the first positioning pattern and the second positioning pattern; The first object and the second object are aligned in a second direction according to the first measurement pattern and the second measurement pattern; The rotation angle between the first object and the second object is calculated based on the first measurement pattern and the second measurement pattern.

2. The angle measurement method according to claim 1, characterized in that, The detection pattern includes a first detection pattern and a second detection pattern. The first object is provided with two first mark patterns, and the positions of the two first mark patterns are symmetrically distributed with respect to the rotation center of the first object. The second object is provided with two second mark patterns, and the positions of the two second mark patterns are symmetrically distributed with respect to the rotation center of the second object. The two first mark patterns and the two second mark patterns correspond one-to-one and form the first detection pattern and the second detection pattern. The step of aligning the first object and the second object in the second direction according to the first measurement pattern and the second measurement pattern includes: Obtain the first displacement difference between the first measurement pattern and the second measurement pattern of the first detection pattern in the second direction, and obtain the second displacement difference between the first measurement pattern and the second measurement pattern of the second detection pattern in the second direction; The first object and the second object are aligned in the second direction based on the first displacement difference and the second displacement difference.

3. The angle measurement method according to claim 1, characterized in that, The step of calculating the rotation angle between the first object and the second object based on the first measurement pattern and the second measurement pattern includes: Obtain the displacement difference between the first measurement pattern and the second measurement pattern in the second direction; Calculate the rotation angle based on the displacement difference; Wherein, the first direction and the second direction are perpendicular.

4. The angle measurement method according to claim 3, characterized in that, The step of obtaining the displacement difference between the first measurement pattern and the second measurement pattern in the second direction includes: Obtain the moiré fringes formed by the first measurement pattern and the second measurement pattern; The displacement difference is calculated based on the moiré fringes.

5. The angle measurement method according to claim 4, characterized in that, The first measurement pattern includes a plurality of first test strips arranged in parallel and spaced apart, and a first convex strip is provided in the middle of the plurality of first test strips; the second measurement pattern includes a plurality of second test strips arranged in parallel and spaced apart, and a second convex strip is provided in the middle of the plurality of second test strips. The step of calculating the displacement difference based on the moiré fringes includes: The first difference is obtained based on the positional relationship between the first convex strip and the second convex strip; The second difference is obtained based on the moiré fringes; The displacement difference is calculated by combining the first difference and the second difference.

6. The angle measurement method according to claim 1, characterized in that, The first positioning pattern includes a first positioning block and a second positioning block located on both sides of the first measurement pattern, and the second positioning pattern includes a third positioning block and a fourth positioning block located on both sides of the second measurement pattern. The first positioning block and the third positioning block are configured such that, during the relative movement of the first object and the second object, the first positioning block does not at least partially overlap with the third positioning block, and the third positioning block does not at least partially overlap with the first positioning block. The second positioning block and the fourth positioning block are configured such that, during the relative movement of the first object and the second object, the second positioning block does not at least partially overlap with the fourth positioning block, and the fourth positioning block does not at least partially overlap with the second positioning block.

7. The angle measurement method according to claim 6, characterized in that, Both the first positioning pattern and the second positioning pattern are provided with a positioning strip and an anti-obstruction strip. The positioning strip and the anti-obstruction strip of the first positioning pattern are parallel, and the positioning strip and the anti-obstruction strip of the second positioning pattern are parallel. The length of the anti-obstruction strip is less than the length of the positioning strip.

8. The angle measurement method according to claim 6, characterized in that, The first positioning block includes a first positioning strip, the second positioning block includes a second positioning strip that is symmetrically distributed with the first positioning strip, the third positioning block includes a third positioning strip, and the fourth positioning block includes a fourth positioning strip that is symmetrically distributed with the third positioning strip. The step of aligning the first object and the second object in a first direction according to the first positioning pattern and the second positioning pattern includes: Align the axis of symmetry between the first and second positioning bars and the axis of symmetry between the third and fourth positioning bars.

9. An angle measuring device, characterized in that, The angle measuring device measures the rotation angle between the first object and the second object using the angle measuring method according to any one of claims 1-8.

10. The angle measuring device according to claim 9, characterized in that, The angle measuring device includes a detector, which includes a first detector and a second detector. The first detector is used to acquire a first detection pattern, and the second detector is used to acquire a second detection pattern. The second object is located between the first object and the detector. A lens assembly is provided between the first object and the second object. The lens assembly is used to project the first marking pattern on the first object, so that the first marking pattern and the second marking pattern form the first detection pattern and the second detection pattern.

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