A system and method for rapidly finding the focal point of a large concave mirror

Abstract

This invention discloses a system and method for rapidly finding the focal point of a large concave mirror. The system comprises: a support, a pentagonal prism, a screen plane, a point light source, a parallel light source, a protractor assembly, a guide rail and a level, and a calculation module. The calculation module utilizes the property that parallel light converges onto the focal plane after passing through the concave mirror. The concave mirror converges parallel light onto the screen plane, finding light spots of the same size formed by three light sources, thus determining a plane parallel to the focal plane. The direction of the optical axis is determined based on the established coordinate system. The point closest to the focal point on the same plane is found as the point through which the optical axis passes. The optical axis is determined based on the established coordinate system, the direction of the optical axis, and the point through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found is taken as the focal point. Using a simple optical path, a pentagonal prism, and an optical axis, the focal point of an unknown concave mirror can be rapidly determined regardless of site conditions.

Description

Technical Field

[0001] This invention relates to the fields of optical design, geometric optics, and spatial geometry calculation, and in particular to a system and method for rapidly finding the focal point of a large concave mirror. Background Technology

[0002] With the development of communication and optoelectronic technologies, large concave mirrors are frequently used in scenarios such as light energy utilization, lighting photography, mirror simulation, radio communication, and optoelectronics to concentrate energy and for virtual imaging.

[0003] As the demand for mirrors continues to increase, their size also grows, and the requirements for precision become increasingly stringent. However, large mirrors inevitably shift and deform in outdoor environments, causing a shift in the original focal point. To maintain accuracy, the mirror needs to be refocused. While professional collimators can be used to measure mirrors in indoor urban environments, these tools are difficult to find outdoors or in emergency situations. Therefore, a method using simple tools is needed to refocus concave mirrors. Summary of the Invention

[0004] To address the aforementioned shortcomings in the existing technology, embodiments of the present invention provide a system and method for rapidly finding the focal point of a large concave mirror.

[0005] In a first aspect, embodiments of the present invention provide a system for quickly finding the focal point of a large concave mirror, comprising: a support, a pentagonal prism, a light screen plane, a point light source, a parallel light source, a protractor assembly, a guide rail and a level, and a calculation module;

[0006] Fix the support, then use a level to adjust the platform on the support, and fix the guide rail on the support. Fix the point light source and parallel light source on the guide rail to ensure that the light source moves in parallel. Then use a pentagonal prism to reflect the light source onto the screen plane. The protractor assembly is used to accurately measure length and angle, and the level is used to level and establish the north-sky-east coordinate system.

[0007] The calculation module utilizes the property that parallel light converges onto the focal plane after passing through a concave mirror. The concave mirror focuses the parallel light onto the screen plane, finding light spots of the same size formed by three light sources, and thus determining a plane parallel to the focal plane. The direction of the optical axis is determined according to the established coordinate system. A pentagonal prism is used to change the direction of the light beam, making it easier to distinguish between incident and outgoing light. The characteristic of the pentagonal prism to change the light path perpendicularly by 90° is used to test the effect of a point light source at different positions on the reflected light, and find the point on the same plane closest to the focal point as the point through which the optical axis passes. The optical axis is determined according to the established coordinate system, the direction of the optical axis, and the point through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found as the focal point.

[0008] In some embodiments, a coordinate system is established with the center of the support base as the origin O and the height h0 of the point above the ground is recorded. The coordinate system has the top as the Z-axis, the east as the X-axis on the horizontal plane, and the north as the Y-axis.

[0009] In some embodiments, the calculation module is further configured to determine the position of the concave mirror and the focal length and other points relative to the focal point based on the point on the optical axis where a point light source reflects parallel light, as the re-adjusted support in the focal point.

[0010] In a second aspect, embodiments of the present invention also provide a method for rapidly finding the focal point of a large concave mirror, applied to the system for rapidly finding the focal point of a large concave mirror as described in the first aspect of claim, comprising:

[0011] By utilizing the property that parallel light converges onto the focal plane after passing through a concave mirror, the concave mirror converges the parallel light onto the screen plane. By finding light spots of the same size formed by three light sources, a plane parallel to the focal plane is determined, and the direction of the optical axis is determined according to the established coordinate system.

[0012] By using a pentagonal prism to change the direction of the light beam, it is easier to distinguish between incident and outgoing light. By using the characteristic of changing the light path by 90° perpendicularly to the pentagonal prism, the influence of a point light source at different positions on the reflected light is tested, and the point on the same plane closest to the focal point is found as the point through which the optical axis passes.

[0013] The optical axis is determined based on the established coordinate system, the direction of the optical axis, and the points through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found and used as the focal point.

[0014] In some embodiments, determining the optical axis direction according to the established coordinate system includes:

[0015] The parallel light source is fixed on the guide rail and moved to ensure that the light source illuminates the concave mirror in the same direction. A screen is placed behind the bracket. Each time the light source is moved, the screen is used to find the focused spot. After each spot is captured, the screen is moved back and forth to observe the trend of the spot size change.

[0016] Three consecutive light spots of the same size and with the same trend of change were captured, and their distances to the ground (h1, h2, h3), the distances from the ground projection to the origin (l1, l2, l3), and the angles (θ1, θ2, θ3) between the line connecting the two points and the X-axis were recorded. The coordinates of the three points (l1 cosθ1, l1 sinθ1, h1-h0), (l2 cosθ2, l2 sinθ2, h2-h0), and (l3 cosθ3, l3 sinθ3, h3-h0) were established, and the plane was further determined.

[0017]

[0018] The optical axis direction (A, B, C) is determined based on this and is considered a fixed value in subsequent calculations.

[0019] In some embodiments, finding the point on the same plane closest to the focal point as the point through which the optical axis passes includes:

[0020] Adjust the guide rail on the support to be perpendicular to the optical axis. Fix the point light source on the guide rail and fix the position of the screen plane. Move the light source along the guide rail. The light reflected by the concave mirror is reflected onto the screen plane by the pentagonal prism. Record the position of the guide rail and the fixed point of the support at (0,0,h). At this time, the guide rail is located at the intersection of the planes Ax+By+Cz=Ch and z=h. Define the angle between the direction of the guide rail and the X-axis. Based on the distance L1 between the guide rail and the fixed point of the bracket, determine the closest point on the guide rail (L1cosθ4,L1sinθ4,h). Draw a straight line through the point where the point light source is located that is perpendicular to both the guide rail and the optical axis.

[0021]

[0022] Keeping the fixed point stationary, change the direction of the guide rail in the plane Ax+By+Cz=Ch perpendicular to the optical axis, so that it is raised by φ around (A,B,C). The value of φ is determined by the protractor, and a new plane parallel to the optical axis is obtained.

[0023]

[0024] Repeat the above steps to find the point light source position on the guide rail that is closest to the focal point:

[0025]

[0026] Let L2 be the distance moved, and the coordinates of the points traversed by the optical axis be:

[0027]

[0028] In some embodiments, determining the optical axis based on the established coordinate system, the optical axis direction, and the points traversed by the optical axis includes:

[0029] In the plane Ax + By + Cz = Ch, the perpendicular line passing through this point is:

[0030]

[0031] The point where the two perpendicular lines intersect on the plane Ax + By + Cz = Ch is a point on the optical axis.

[0032]

[0033]

[0034] The coordinates of this point are simplified to (a, b, c), which are treated as fixed values ​​in subsequent calculations. Therefore, the optical axis can be determined as follows:

[0035]

[0036] In some embodiments, finding a point on the optical axis from which a point light source reflects parallel light, as the focal point, includes:

[0037] Adjust the bracket height so that the height H of the guide rail fixing point is... The guide rail is then aligned with the optical axis. A point light source is fixed on the guide rail and moved back and forth along the guide rail. Each time the light source is moved, the pentagonal prism is kept fixed while the screen plane is moved back and forth. The size of the light spot reflected by the concave mirror and the pentagonal prism is measured.

[0038] When the size of the light spot no longer changes with the position of the screen plane, the point light source is located at the focal point. The distance between the focal point and the fixed point is recorded as L3. At this time, the position of the focal point is...

[0039] In some embodiments, after determining the optical axis based on the optical axis direction and the points through which the optical axis passes, and finding the point on the optical axis where the point light source reflects parallel light as the focal point, the process includes:

[0040] According to the steps, find the point on the optical axis from which the point light source reflects parallel light. Use this as the focal point to determine the position of the concave mirror in the readjusted support, and determine the focal length and the relative focal positions of other points.

[0041] In some embodiments, the steps of finding a point on the optical axis from which parallel light is reflected from a point light source, using this point as the focal point, and determining the position of the concave mirror and the focal length and other points relative to the focal point include:

[0042] The position of the concave mirror is determined by the readjusted bracket, and the point on the optical axis where the point light source reflects parallel light is found as the focal point. The guide rail built in the process is fixed with (0, 0, H) as the guide rail and the bracket fixing point. The point light source no longer moves to illuminate the concave mirror, and the center position of the light spot is marked as P0.

[0043] Define the plane of rotation as The point light source is fixed on the guide rail and does not move further.

[0044] Rotate the guide rail up and down in the plane. When the light spot is internally tangent to the concave mirror, record the rotation angle Φ1. When the light spot is externally tangent to the concave mirror, record the rotation angle Φ2. Mark the internal and external tangency points P1 and P2, and record their distances L4 and L5 from P0.

[0045] Rotate the guide rail in the opposite direction and record the rotation angles of the inner tangent point and the outer tangent point, Φ3 and Φ4. Similarly, mark the tangent points P3 and P4 and record their distances from P0, L6 and L7. Measure the distance l4 between the two inner tangent points and the distance l5 between the two outer tangent points.

[0046] If the internal and external tangent points coincide and the rotation angles are symmetrical, it indicates that the concave mirror is... Maintaining internal symmetry, the focal length is [value missing]. Mirror depth is

[0047] If the concave mirror is deformed and does not satisfy strict symmetry, the difference between the upper and lower measurements is averaged to make up the difference, and the focal length is... Mirror depth is At this time, the position of P0 is:

[0048] The position of P2 (or the midpoint between P1 and P2) is:

[0049] The position of P3 (or the midpoint between P3 and P4) is: At this point, determine the relative positions of each point on the concave mirror and the relative position of the focal point in the North-East coordinate system.

[0050] This invention provides a system and method for rapidly finding the focal point of a large concave mirror. By utilizing a simple optical path and a pentagonal prism and optical axis, it enables the rapid determination of the focal point of an unknown concave mirror without being constrained by site conditions. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of a method for determining the optical axis direction of a concave mirror provided in an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of a method for determining the optical axis of a concave mirror with a known optical axis direction according to the present invention;

[0053] Figure 3 This is a schematic diagram of a method for determining the focal point of a concave mirror with a known optical axis according to the present invention;

[0054] Figure 4 This is a schematic diagram of a method for determining the focal length of a concave mirror with a known focal position and the position of the focal point relative to the mirror boundary according to the present invention;

[0055] Explanation of reference numerals in the attached figures:

[0056] The components include a support (1), a pentagonal prism (2), a light screen (3), a point light source (4), a parallel light source (5), a protractor assembly, a guide rail (6), and a level (7). Detailed Implementation

[0057] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and that those skilled in the art will fully understand the scope of the invention.

[0058] Where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0059] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0060] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated features, integrals, steps, operations, elements, and / or components is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0061] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be understood to have the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be understood to have an idealized or overly formal meaning unless expressly so defined herein.

[0062] To address the issue of the strong dependence of focusing on location-dependent concave mirrors on equipment and site conditions, this invention provides a system and method for rapidly finding the focal point of a large concave mirror.

[0063] To enable those skilled in the art to better understand the technical solution, the following describes in detail, with reference to the accompanying drawings, a system and method for rapidly finding the focal point of a large concave mirror provided by the present invention.

[0064] Firstly, such as Figure 1 , Figure 2 As shown, this embodiment of the invention provides a system for quickly finding the focal point of a large concave mirror, which includes: a support (1), a pentagonal prism (2), a light screen (3), a point light source (4), a parallel light source (5), a protractor assembly, a guide rail (6), a level (7), and a calculation module;

[0065] Fix the bracket (1), then use the level (7) to adjust the platform on the bracket (1), and fix the guide rail (6) on the bracket (1). Fix the point light source (4) and the parallel light source (5) on the guide rail (6) to ensure that the light source moves in parallel. Then use the pentagonal prism (2) to reflect the light source onto the screen plane (3). The protractor assembly is used to accurately measure the length and angle, and the level (7) is used to level and establish the north-sky-east coordinate system.

[0066] The calculation module utilizes the property that parallel light converges onto the focal plane after passing through a concave mirror. The concave mirror focuses the parallel light onto the screen plane, finding light spots of the same size formed by three light sources, and thus determining a plane parallel to the focal plane. The direction of the optical axis is determined according to the established coordinate system. A pentagonal prism is used to change the direction of the light beam, making it easier to distinguish between incident and outgoing light. The characteristic of the pentagonal prism to change the light path perpendicularly by 90° is used to test the effect of a point light source at different positions on the reflected light, and find the point on the same plane closest to the focal point as the point through which the optical axis passes. The optical axis is determined according to the established coordinate system, the direction of the optical axis, and the point through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found as the focal point.

[0067] It should be noted that the bracket (1) is a fixed bracket. The level (7) is a compass level.

[0068] This invention provides a system for rapidly finding the focal point of a large concave mirror. By using a simple optical path and a pentagonal prism and optical axis, it enables the rapid determination of the focal point of an unknown concave mirror without being constrained by site conditions.

[0069] In some embodiments, such as Figure 1 As shown, a coordinate system is established with the center of the base of the bracket (1) as the origin O and the height h0 of the point above the ground is recorded. The coordinate system has the Z-axis directly above, the X-axis directly east on the horizontal plane, and the Y-axis directly north.

[0070] In this coordinate system, the height of the support, the length of the light source's movement on the guide rail, and the position of the concave mirror relative to the support can be measured using a measuring tape, and their corresponding coordinates can be calculated. Based on the established coordinate system, the direction of the optical axis can be found, and the optical axis can be further determined.

[0071] In some embodiments, the calculation module is further configured to determine the position of the concave mirror and the focal length and other points relative to the focal point based on the point on the optical axis where a point light source reflects parallel light, as the re-adjusted support in the focal point.

[0072] In a second aspect, embodiments of the present invention also provide a method for rapidly finding the focal point of a large concave mirror, applied to the system for rapidly finding the focal point of a large concave mirror as described in the first aspect of claim, comprising:

[0073] By utilizing the property that parallel light converges onto the focal plane after passing through a concave mirror, the concave mirror converges the parallel light onto the screen plane. By finding light spots of the same size formed by three light sources, a plane parallel to the focal plane is determined, and the direction of the optical axis is determined according to the established coordinate system.

[0074] Using a pentagonal prism (2) to change the direction of the beam makes it easier to distinguish between incident and outgoing light. Using a pentagonal prism (2) to change the light path at a 90° angle vertically, the influence of the point light source on the reflected light at different positions is tested, and the point closest to the focal point on the same plane is found as the point through which the optical axis passes.

[0075] The optical axis is determined based on the established coordinate system, the direction of the optical axis, and the points through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found and used as the focal point.

[0076] This invention provides a method for quickly finding the focal point of a large concave mirror. By using a simple optical path and a pentagonal prism and optical axis, it is possible to quickly determine the focal point of an unknown concave mirror without being restricted by site conditions.

[0077] In some embodiments, such as Figure 1 As shown, determining the optical axis direction based on the established coordinate system includes:

[0078] The parallel light source is fixed on the guide rail (6) and moved to ensure that the light source illuminates the concave mirror in the same direction. A screen plane (3) is placed behind the bracket (1). Each time the light source is moved, the screen plane (3) is used to find the focused light spot. Each time the light spot is captured, the screen plane (3) is moved back and forth to observe the trend of the light spot size change.

[0079] Three consecutive light spots of the same size and with the same trend of change were captured, and their distances to the ground (h1, h2, h3), the distances from the ground projection to the origin (l1, l2, l3), and the angles (θ1, θ2, θ3) between the line connecting the two points and the X-axis were recorded. The coordinates of the three points (l1 cosθ1, l1 sinθ1, h1-h0), (l2 cosθ2, l2 sinθ2, h2-h0), and (l3 cosθ3, l3 sinθ3, h3-h0) were established, and the plane was further determined.

[0080]

[0081] The optical axis direction (A, B, C) is determined based on this and is considered a fixed value in subsequent calculations.

[0082] like Figure 1As shown, h1 is the distance from the ground to a light spot of the same size and with the same trend of change, l1 is the distance from the corresponding ground projection to the origin O, and θ1 is the angle between the line connecting the two and the X-axis. h2 and h3 are similar to h1, l2 and l3 are similar to l1, and θ2 and θ3 are similar to θ1. They are not shown in the figure.

[0083] This invention uses only one parallel light source, and in this step, the parallel light source moves along the guide rail.

[0084] In this embodiment of the invention, the characteristic of parallel light converging on the focal plane after passing through a concave mirror is utilized. The concave mirror converges the parallel light onto the screen plane (3). Since the convergence focal plane is difficult to locate accurately, we can instead look for light spots of the same size formed by three light sources, and then determine a plane parallel to the focal plane to determine the direction of the optical axis.

[0085] In some embodiments, such as Figure 2 As shown, find the point on the same plane that is closest to the focal point, as the point through which the optical axis passes, including:

[0086] Adjust the upper guide rail (6) of the bracket (1) to be perpendicular to the optical axis (e.g., Figure 2 At this time, the guide rail is Figure 1 Adjust the guide rail direction 2 to guide rail direction 1), fix the point light source (4) on the guide rail (6), fix the position of the screen plane (3), move the light source along the guide rail, and the light reflected by the concave mirror is reflected onto the screen plane by the pentagonal prism (2). Record the position of the fixed point (0,0,h) of the guide rail (6) and the bracket (1) at this time. At this time, the guide rail (1) is located at the intersection of the plane Ax+By+Cz=Ch and z=h. Define the angle between the guide rail direction and the X-axis. Based on the distance L1 between the guide rail and the fixed point of the bracket, determine the closest point (L1cosθ4,L1sinθ4,h) on the guide rail (6). Draw a straight line perpendicular to both the guide rail and the optical axis through the point where the point light source (4) is located at this time.

[0087]

[0088] Keeping the fixed point stationary, change the direction of the guide rail in the plane Ax+By+Cz=Ch perpendicular to the optical axis, so that it is raised by φ around (A,B,C). The value of φ is determined by the protractor, and a new plane parallel to the optical axis is obtained.

[0089]

[0090] Repeat the above steps to find the point light source position on the guide rail that is closest to the focal point:

[0091]

[0092] Let L2 be the distance moved, and the coordinates of the points traversed by the optical axis be:

[0093]

[0094] This invention uses only one point light source, and in this step, the point light source moves along the guide rail.

[0095] This invention proposes a method for determining the optical axis of a concave mirror when the optical axis direction is known. The method utilizes a bracket, a pentagonal prism, a screen plane, a point light source, a measuring tape assembly, and a guide rail. The pentagonal prism changes the direction of the light beam, making it easier to distinguish between incident and outgoing light. By utilizing its ability to change the light path perpendicularly by 90°, the influence of the point light source on the reflected light at different positions can be tested. Furthermore, since the beam reflected by the pentagonal prism has the same thickness, it can be observed that the point light source is closest to the focal point when the light spot is smallest, which is the point through which the optical axis passes.

[0096] In some embodiments, such as Figure 2 As shown, the optical axis is determined based on the established coordinate system, the direction of the optical axis, and the points through which the optical axis passes, including:

[0097] In the plane Ax + By + Cz = Ch, the perpendicular line passing through this point is:

[0098]

[0099] The point where the two perpendicular lines intersect on the plane Ax + By + Cz = Ch is a point on the optical axis.

[0100]

[0101] The coordinates of this point are simplified to (a, b, c), which are treated as fixed values ​​in subsequent calculations. Therefore, the optical axis can be determined as follows:

[0102]

[0103] In some embodiments, such as Figure 3 As shown, the point on the optical axis where a point light source reflects parallel light is located, serving as the focal point, including:

[0104] Adjust the height of bracket (1) so that the height H of the fixed point of guide rail (6) is The guide rail (6) is adjusted to coincide with the optical axis. A point light source (4) is fixed on the guide rail (6) and moved back and forth along the guide rail (6). Each time the light source is moved, the pentagonal prism (2) is kept fixed and the screen plane (3) is moved back and forth. The size of the light spot reflected by the concave mirror and the pentagonal prism is measured.

[0105] When the size of the light spot no longer changes with the position of the screen plane, the point light source (4) is located at the focal point. The distance between the focal point and the fixed point is recorded as L3. At this time, the position of the focal point is...

[0106] This invention uses only one point light source, which moves along the guide rail in this step.

[0107] This invention utilizes a known optical axis and a method for finding the focal point on the optical axis by moving the light source back and forth. Similarly, it uses a bracket, a pentagonal prism, a light screen plane, a point light source, a measuring tape assembly, and a guide rail to find the point on the optical axis where parallel light is reflected from the point light source, i.e., the focal point.

[0108] In some embodiments, after determining the optical axis based on the optical axis direction and the points through which the optical axis passes, and finding the point on the optical axis where the point light source reflects parallel light as the focal point, the process includes:

[0109] According to the steps, find the point on the optical axis from which the point light source reflects parallel light, and use it as the focal point. Then, readjust the support (1) to determine the position of the concave mirror and the focal length and other points relative to the focal point.

[0110] In some embodiments, such as Figure 4 As shown, according to the steps, the point on the optical axis where the point light source reflects parallel light is found, which serves as the focal point. The re-adjusted support is used to determine the position of the concave mirror and the focal length and the relative positions of other points to the focal point, including:

[0111] Using the readjusted bracket (1), the position of the concave mirror is determined, and the point on the optical axis where the point light source (4) reflects parallel light is found as the focal point. The guide rail built in this process is fixed at (0, 0, H) with the bracket as the guide rail fixing point. Figure 3 The fixed point light source (4) is no longer moved to illuminate the concave mirror, and the center position of the light spot is marked as P0;

[0112] Define the plane of rotation as The point light source (4) is fixed on the guide rail (6) and does not move further;

[0113] Rotate the guide rail (6) up and down in the plane. When the light spot is internally tangent to the concave mirror, record the rotation angle Φ1. When the light spot is externally tangent to the concave mirror, record the rotation angle Φ2. Mark the internal and external tangency points P1 and P2, and record their distances from P0 L4 and L5.

[0114] Rotate the guide rail in the opposite direction (6) and record the rotation angles of the inner tangent point and the outer tangent point Φ3 and Φ4 (similar to Φ1 and Φ2). Figure 4 (Not shown), similarly mark the tangent points P3 and P4, and record their distances to P0 L6 and L7. Measure the distance l4 between the two inner tangent points and the distance l5 between the two outer tangent points;

[0115] If the internal and external tangent points coincide and the rotation angles are symmetrical, it indicates that the concave mirror is... Maintaining internal symmetry, the focal length is [value missing]. Mirror depth is

[0116] If the concave mirror is deformed and does not satisfy strict symmetry, the difference between the upper and lower measurements is averaged to make up the difference, and the focal length is... Mirror depth is At this time, the position of P0 is:

[0117] The position of P2 (or the midpoint between P1 and P2) is:

[0118] The position of P3 (or the midpoint between P3 and P4) is:

[0119] At this point, determine the relative positions of all points on the concave mirror and the relative position of the focal point in the north-east coordinate system. Record the test points, and then find the focal point again. Using this fixed-focus mark and measurement values, calculate the relative positions of the mirror edge, center point, and focal point in the same coordinate system when the concave mirror does not move.

[0120] This invention uses only one point light source. In this step, the point light source is fixed on the guide rail, and the point light source does not move while the guide rail moves.

[0121] This invention proposes a method for determining the relative position of a known focal point and a point on a concave mirror. The method utilizes a support, a pentagonal prism, a screen plane, a point light source, a measuring tape and protractor assembly, and a guide rail, and uses the Pythagorean theorem to determine the relative position of the focal length and the edge and center of the mirror.

[0122] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for general illustrative purposes only and should not be construed as limiting. In some embodiments, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in connection with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth by the appended claims.

Claims

1. A system for rapidly finding the focal point of a large concave mirror, characterized in that, It includes: The system consists of a support frame, a pentagonal prism, a light screen, a point light source, a parallel light source, a protractor assembly, a guide rail and a level, and a calculation module. Fix the support, then use a level to adjust the platform on the support, and fix the guide rail on the support. Fix the point light source and parallel light source on the guide rail to ensure that the light source moves in parallel. Then use a pentagonal prism to reflect the light source onto the screen plane. The protractor assembly is used to accurately measure length and angle, and the level is used to level and establish the north-sky-east coordinate system. The calculation module utilizes the property that parallel light converges onto the focal plane after passing through a concave mirror. The concave mirror converges the parallel light onto the screen plane, finds light spots of the same size formed by three light sources, and then determines a plane parallel to the focal plane. Based on the established coordinate system, the direction of the optical axis is determined. By using a pentagonal prism to change the direction of the light beam, it is easier to distinguish between incident and outgoing light. By using the characteristic of changing the light path by 90° perpendicularly to the pentagonal prism, the influence of a point light source at different positions on the reflected light is tested, and the point on the same plane closest to the focal point is found as the point through which the optical axis passes. The optical axis is determined based on the established coordinate system, the direction of the optical axis, and the points through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found and used as the focal point.

2. The system for rapidly finding the focal point of a large concave mirror according to claim 1, characterized in that, Establish a coordinate system with the center of the support base as the origin O and record the height h0 of this point above the ground. The coordinate system has the top as the Z-axis, the east as the X-axis and the north as the Y-axis on the horizontal plane.

3. The system for rapidly finding the focal point of a large concave mirror according to claim 1, characterized in that, The calculation module is also used to determine the position of the concave mirror and the focal length and other points relative to the focal point by finding the point on the optical axis where the point light source reflects parallel light, and using the readjusted support in the focal point.

4. A method for rapidly finding the focal point of a large concave mirror, characterized in that, The system for rapidly finding the focal point of a large concave mirror as described in any one of claims 1-3 comprises: By utilizing the property that parallel light converges onto the focal plane after passing through a concave mirror, the concave mirror converges the parallel light onto the screen plane. By finding light spots of the same size formed by three light sources, a plane parallel to the focal plane is determined, and the direction of the optical axis is determined according to the established coordinate system. By using a pentagonal prism to change the direction of the light beam, it is easier to distinguish between incident and outgoing light. By using the characteristic of changing the light path by 90° perpendicularly to the pentagonal prism, the influence of a point light source at different positions on the reflected light is tested, and the point on the same plane closest to the focal point is found as the point through which the optical axis passes. The optical axis is determined based on the established coordinate system, the direction of the optical axis, and the points through which the optical axis passes. The point on the optical axis where the point light source reflects parallel light is found and used as the focal point.

5. The method for rapidly finding the focal point of a large concave mirror according to claim 4, characterized in that, Determining the direction of the optical axis based on the established coordinate system includes: The parallel light source is fixed on the guide rail and moved to ensure that the light source illuminates the concave mirror in the same direction. A screen is placed behind the bracket. Each time the light source is moved, the screen is used to find the focused spot. After each spot is captured, the screen is moved back and forth to observe the trend of the spot size change. Three consecutive light spots of the same size and with the same trend of change were captured, and their distances to the ground (h1, h2, h3), the distances from the ground projection to the origin (l1, l2, l3), and the angles (θ1, θ2, θ3) between the line connecting the two points and the X-axis were recorded. The coordinates of the three points (l1cosθ1, l1sinθ1, h1-h0), (l2cosθ2, l2sinθ2, h2-h0), and (l3cosθ3, l3sinθ3, h3-h0) were established, and the plane was further determined. The optical axis direction (A, B, C) is determined based on this and is considered a fixed value in subsequent calculations.

6. The method for rapidly finding the focal point of a large concave mirror according to claim 5, characterized in that, Find the point on the same plane that is closest to the focal point, and use it as the point through which the optical axis passes, including: Adjust the guide rail on the support to be perpendicular to the optical axis. Fix the point light source on the guide rail and fix the position of the screen plane. Move the light source along the guide rail. The light reflected by the concave mirror is reflected onto the screen plane by the pentagonal prism. Record the position of the guide rail and the fixed point of the support at (0,0,h). At this time, the guide rail is located at the intersection of the planes Ax+By+Cz=Ch and z=h. Define the angle between the direction of the guide rail and the X-axis. Based on the distance L1 between the guide rail and the fixed point of the bracket, determine the closest point on the guide rail (L1cosθ4,L1sinθ4,h). Draw a straight line through the point where the point light source is located that is perpendicular to both the guide rail and the optical axis. Keeping the fixed point stationary, change the direction of the guide rail in the plane Ax+By+Cz=Ch perpendicular to the optical axis, so that it is raised by φ around (A,B,C). The value of φ is determined by the protractor, and a new plane parallel to the optical axis is obtained. Repeat the above steps to find the point light source position on the guide rail that is closest to the focal point: Let L2 be the distance moved, and the coordinates of the points traversed by the optical axis be:

7. The method for rapidly finding the focal point of a large concave mirror according to claim 6, characterized in that, The optical axis is determined based on the established coordinate system, the direction of the optical axis, and the points through which the optical axis passes, including: In the plane Ax + By + Cz = Ch, the perpendicular line passing through this point is: The point where the two perpendicular lines intersect on the plane Ax + By + Cz = Ch is a point on the optical axis. The coordinates of this point are simplified to (a, b, c), which are treated as fixed values ​​in subsequent calculations. Therefore, the optical axis can be determined as follows:

8. The method for rapidly finding the focal point of a large concave mirror according to claim 7, characterized in that, Find the point on the optical axis from which parallel light is reflected from a point light source, and use this point as the focal point, including: Adjust the bracket height so that the height H of the guide rail fixing point is... The guide rail is then aligned with the optical axis. A point light source is fixed on the guide rail and moved back and forth along the guide rail. Each time the light source is moved, the pentagonal prism is kept fixed while the screen plane is moved back and forth. The size of the light spot reflected by the concave mirror and the pentagonal prism is measured. When the size of the light spot no longer changes with the position of the screen plane, the point light source is located at the focal point. The distance between the focal point and the fixed point is recorded as L3. At this time, the position of the focal point is...

9. The method for rapidly finding the focal point of a large concave mirror according to claim 8, characterized in that, The optical axis is determined based on its direction and the points it passes through. Then, the point on the optical axis where parallel light is reflected from a point light source is found and designated as the focal point. This process includes: According to the steps, find the point on the optical axis from which the point light source reflects parallel light. Use this as the focal point to determine the position of the concave mirror in the readjusted support, and determine the focal length and the relative focal positions of other points.

10. The method for rapidly finding the focal point of a large concave mirror according to claim 9, characterized in that, According to the steps, find the point on the optical axis where the point light source reflects parallel light. Use this point as the focal point, and determine the position of the concave mirror and the focal length and the relative positions of other points to the focal point, including: The position of the concave mirror is determined by the readjusted bracket, and the point on the optical axis where the point light source reflects parallel light is found as the focal point. The guide rail built in the process is fixed with (0, 0, H) as the guide rail and the bracket fixing point. The point light source no longer moves to illuminate the concave mirror, and the center position of the light spot is marked as P0. Define the plane of rotation as The point light source is fixed on the guide rail and does not move further. Rotate the guide rail up and down in the plane. When the light spot is internally tangent to the concave mirror, record the rotation angle Φ1. When the light spot is externally tangent to the concave mirror, record the rotation angle Φ2. Mark the internal and external tangency points P1 and P2, and record their distances L4 and L5 from P0. Rotate the guide rail in the opposite direction and record the rotation angles of the inner tangent point and the outer tangent point, Φ3 and Φ4. Similarly, mark the tangent points P3 and P4 and record their distances from P0, L6 and L7. Measure the distance l4 between the two inner tangent points and the distance l5 between the two outer tangent points. If the internal and external tangent points coincide and the rotation angles are symmetrical, it indicates that the concave mirror is... Maintaining internal symmetry, the focal length is [value missing]. Mirror depth is If the concave mirror is deformed and does not satisfy strict symmetry, the difference between the upper and lower measurements is averaged to make up the difference, and the focal length is... Mirror depth is At this time, the position of P0 is: The position of P2 (or the midpoint between P1 and P2) is: The position of P3 (or the midpoint between P3 and P4) is: At this point, determine the relative positions of each point on the concave mirror and the relative position of the focal point in the North-East coordinate system.

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