Aperture diaphragm adjustment method and adjustment device for terahertz imaging system

Abstract

The present invention provides an aperture diaphragm adjustment method for a terahertz imaging system, which can achieve the size adjustment of an aperture diaphragm at the level of hundreds of millimeters, and is light in size and convenient to adjust. It has a wide range of applications in the field of terahertz imaging. It combines a plurality of aperture blades to form a fan blade structure with a closed central area in a closed state, and each aperture blade is provided with a rotation connection point on the periphery, and the rotation shaft of a single steering gear is fixedly connected to the rotation connection point of the corresponding aperture blade, and the array angle of the aperture blades is synchronously controlled by the same steering gear rotation angle controller, so as to achieve the synchronous movement of each aperture blade, thereby changing the size of the aperture diaphragm in the central area corresponding to the fan blade structure.

Description

Technical Field

[0001] The present invention relates to the technical field of terahertz imaging, and in particular to an aperture diaphragm adjustment method for a terahertz imaging system. The present invention also provides an aperture diaphragm adjustment device for a terahertz imaging system. Background Art

[0002] The terahertz imaging system receives the terahertz waves emitted by the object and focuses them onto the terahertz detector through the terahertz optical system, thereby imaging the object. Its working principle is as follows: Figure 1 shown.

[0003] Figure 1 In the embodiment, the terahertz wave emitted by the object 1 passes through the transmission optical system 2 mounted on the fixed frame 3, and is focused on the focal plane of the terahertz detector 4 to form a terahertz image 5. Since the aperture of the transmission optical system 2 is usually in the order of hundreds of millimeters and the weight is often large, it needs to be firmly embedded in the mounting hole 6 of the fixed frame 3. The mounting hole 6 also plays the role of the aperture stop of the terahertz optical system 2, which is used to limit the amount of light entering the terahertz wave, such as Figure 2 shown.

[0004] For an optical system, changing the size of its aperture diaphragm can change the depth of field of the system, improve the vignetting of the image, adjust the response of the detector, etc. Therefore, the size of the aperture diaphragm of most optical systems is adjustable. The principle is to install a mechanical linkage mechanism between the multiple leaves that make up the aperture diaphragm to achieve the synchronous movement of each leaf, thereby changing the size of the aperture diaphragm between the leaves, such as Figure 3 For most optical systems working in the visible light band, the diameter of the aperture diaphragm is generally between a few millimeters and tens of millimeters, so the adjustment mechanism of the aperture diaphragm is very light and can be adjusted directly by hand.

[0005] However, for terahertz imaging systems, since their wavelength is hundreds of times that of visible light, the size and weight of their optical systems are also several or even dozens of times that of visible light optical systems. Figure 2 In a typical transmission terahertz imaging system, the aperture diameter is generally hundreds of millimeters. If the traditional aperture adjustment scheme is still used, the blade linkage mechanism will become very bulky and inconvenient to adjust by hand, which greatly affects its practicality. Therefore, the current terahertz imaging systems all use fixed-size apertures, and there is no practical adjustable aperture.

[0006] The inability to adjust the size of the aperture diaphragm limits the imaging effect of the terahertz imaging system to a certain extent. Therefore, it is necessary to design a lightweight and practical aperture diaphragm adjustment method and adjustment device for the terahertz imaging system to obtain better terahertz images. Summary of the invention

[0007] In view of the above problems, the present invention provides an aperture diaphragm adjustment method for a terahertz imaging system, which can achieve size adjustment of the aperture diaphragm at the level of hundreds of millimeters, is lightweight and easy to adjust, and has wide applications in the field of terahertz imaging.

[0008] A method for adjusting the aperture diaphragm of a terahertz imaging system is characterized in that: a plurality of aperture blades are combined to form a fan blade structure with a closed central area in a closed state, each aperture blade is provided with a rotation connection point on the periphery, a rotation shaft of a single servo is fixedly connected to the rotation connection point of the corresponding aperture blade, and the array angle of the aperture blades is synchronously controlled by the same servo angle controller to achieve synchronous movement of the aperture blades, thereby changing the size of the aperture diaphragm of the central area corresponding to the fan blade structure.

[0009] It is further characterized by:

[0010] In the initial position, the output angle of each servo is 0°, and the central area is closed, that is, the aperture diaphragm is 0. The partial surface area of ​​one end of any aperture blade away from the rotation axis covers the partial surface area of ​​the corresponding end of the adjacent aperture blade, and the end of each aperture blade away from the rotation axis covers the center of the aperture diaphragm, ensuring the closed arrangement of the central area;

[0011] The output angle of the servo angle controller for each servo is synchronously rotated clockwise or counterclockwise, ensuring that the aperture diaphragm is synchronously increased or decreased through the rotation of several diaphragm blades;

[0012] When the output angle of the servo angle controller driving the servo is 90°, the size of the aperture diaphragm reaches its maximum. When the output angle is greater than 90°, the partial surface area of ​​the end of the diaphragm blade away from the rotation axis cannot cover the corresponding end of the adjacent diaphragm blade, making the entire central area a non-closed surface area and unable to operate normally.

[0013] The aperture stop adjustment device of the terahertz imaging system is characterized in that it comprises:

[0014] A plurality of aperture blades, each of which has a rotation connection point integrated therein;

[0015] Several steering gears;

[0016] A steering gear angle controller;

[0017] Each servo is arranged one by one corresponding to the aperture blades, and the rotating connection points are connected through the rotating shaft of the servo. All the rotating shafts are arranged in a circular array on the periphery of the equivalent circle center and arranged at intervals. All the servos are fixed on the corresponding fixed object, and the center of the fixed object is hollowed out.

[0018] The steering gear angle controller is connected to the control input end of each steering gear through a line; the steering gear angle controller controls each steering gear to rotate the output shaft at the same angle and the same rotation direction;

[0019] In the initial position, the output angle of each servo is 0°. At this time, the central area is closed, that is, the aperture diaphragm is 0. The partial surface area of ​​one end of any aperture blade away from the rotation axis blocks the partial surface area of ​​the corresponding end of the adjacent aperture blade, and the end of each aperture blade away from the rotation axis covers the center of the aperture diaphragm.

[0020] It is further characterized by:

[0021] The servos are all arranged on the back side of the aperture blades, and the rotation axis does not protrude from the aperture blades, so as to ensure that no interference occurs during movement;

[0022] Each of the aperture blades includes a large arc end edge, a small arc end edge, a first arc transition edge, and a second arc transition edge. The rotation axis is arranged close to the large arc end edge, and the small arc end edge is arranged away from the rotation axis. The two sides of the large arc end edge are connected to the corresponding sides of the small arc end edge through the first arc transition edge and the second arc transition edge respectively, ensuring that the aperture blade has small resistance during rotation and is convenient for forming an aperture aperture.

[0023] After adopting the above technical scheme, since the servo has a small size, a large driving force, and convenient angle control, the method of using the servo blade array can achieve the adjustment of a large aperture diaphragm suitable for a reliable terahertz imaging system with a small size, a light weight and a simple control method; it can achieve the size adjustment of an aperture diaphragm of hundreds of millimeters, and it is light in size and easy to adjust. In the field of terahertz imaging, it has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the terahertz imaging principle of the prior art;

[0025] Figure 2 A schematic diagram of the assembly of an existing transmissive optical system for terahertz imaging;

[0026] Figure 3 A schematic diagram of the adjustment structure of the aperture diaphragm of an existing optical system;

[0027] Figure 4 It is a schematic diagram of the device corresponding to the present invention outputting a 0° angle instruction state;

[0028] Figure 5 This is a schematic diagram of the device corresponding to the present invention outputting a 30° angle instruction state;

[0029] Figure 6This is a schematic diagram of the device corresponding to the present invention outputting a 60° angle instruction state;

[0030] Figure 7 This is a schematic diagram of the device corresponding to the present invention outputting a 90° angle instruction state;

[0031] Figure 8 It is a schematic diagram of assembling a single aperture blade of the present invention;

[0032] Fig. 9 This is a side view of the connection between a single aperture blade, a single steering gear and a steering gear angle controller of the present invention; the names corresponding to the serial numbers in the figure are as follows:

[0033] Object 1, transmissive optical system 2, fixed frame 3, terahertz detector 4, terahertz image 5, mounting hole 6

[0034] Aperture blades 10 , large arc end edge 11 , small arc end edge 12 , first arc transition edge 13 , second arc transition edge 14 , rotation shaft 20 , steering gear 30 , steering gear angle controller 40 , aperture diaphragm 50 , circuit 60 . DETAILED DESCRIPTION

[0035] A method for adjusting the aperture stop of a terahertz imaging system, see Figure 4-Figure 7 : It combines a plurality of aperture blades 10 to form a fan blade structure with a closed central area in a closed state, each aperture blade 10 is provided with a rotation connection point on the periphery, and the rotation shaft 20 of a single servo 30 is fixedly connected to the rotation connection point of the corresponding aperture blade 10, and the array angle of the aperture blade 10 is synchronously controlled by the same servo angle controller 40 to achieve synchronous movement of each aperture blade 10, thereby changing the size of the aperture diaphragm 50 in the central area corresponding to the fan blade structure.

[0036] In the initial position, the output angle of each servo 30 is 0°, and the central area is closed, that is, the aperture diaphragm 50 is 0, and the partial surface area of ​​one end of any aperture blade 10 away from the rotation axis 20 blocks the partial surface area of ​​the corresponding end of the adjacent aperture blade 10, and the end of each aperture blade 10 away from the rotation axis 20 covers the center of the aperture diaphragm 50, ensuring the closed arrangement of the central area;

[0037] The output angle of each servo 30 of the servo angle controller 40 is synchronously rotated clockwise or counterclockwise, ensuring that the aperture diaphragm 50 is synchronously increased or decreased through the rotation of a plurality of diaphragm blades 10;

[0038] When the output angle of the servo angle controller 40 driving the servo 30 is 90°, the size of the aperture diaphragm 50 reaches its maximum. When the output angle is greater than 90°, the partial surface area of ​​the end of the diaphragm blade 10 away from the rotating shaft 20 cannot cover the corresponding end of the adjacent diaphragm blade 10, making the entire central area a non-closed surface area and unable to operate normally.

[0039] Aperture diaphragm adjustment device for terahertz imaging system, see Figure 4-Figure 8 , which comprises: a plurality of aperture blades 10, a plurality of steering gears 30, and a steering gear angle controller 40; each aperture blade 10 is integrated with a rotation connection point; each steering gear 30 is arranged one by one corresponding to the aperture blades 10, and is connected to the rotation connection point through the rotation shaft 2 of the steering gear, all the rotation shafts 2 are arranged in a circular array on the periphery of the equivalent circle center and arranged at intervals, all the steering gears 30 are fixed on the corresponding fixed object, and the center of the fixed object is hollowed out;

[0040] The steering gear angle controller 40 is connected to the control input end of each steering gear 30 through the line 60; the steering gear angle controller 40 controls each steering gear to rotate the rotating shaft 20 at the same angle and the same rotation direction;

[0041] In the initial position, the output angle of each servo 30 is 0°, and the central area is closed, that is, the aperture diaphragm 50 is 0, and the partial surface area of ​​one end of any aperture blade 10 away from the rotation axis blocks the partial surface area of ​​the corresponding end of the adjacent aperture blade 10, and the end of each aperture blade 10 away from the rotation axis 20 covers the center of the aperture diaphragm 50.

[0042] The servos 30 are all arranged on the back side of the aperture blades 10, and the rotation axis 2 does not protrude from the front surface of the aperture blades 10, so as to ensure that there is no interference during movement;

[0043] Each aperture blade 10 includes a large arc-shaped end edge 11, a small arc-shaped end edge 12, a first arc-shaped transition edge 13, and a second arc-shaped transition edge 14. The rotation axis 20 is arranged close to the large arc-shaped end edge 11, and the small arc-shaped end edge 12 is arranged away from the rotation axis 20. The two sides of the large arc-shaped end edge 11 are connected to the corresponding sides of the small arc-shaped end edge 12 through the first arc-shaped transition edge 13 and the second arc-shaped transition edge 14 respectively, to ensure that the aperture blade 10 has small resistance during rotation and is convenient to form an aperture aperture.

[0044] In a specific embodiment, the size of the aperture blade 10 is 200 mm, and the circular array formed by the rotating shafts 20 corresponding to the six aperture blades 10 is as follows: Figure 4-Figure 7As shown, the maximum diameter of the adjustable aperture formed by the circular array is about 250mm, and the steering gear is a small steering gear with an output torque of 20kg·cm, which is sufficient to drive an aluminum alloy or plastic aperture blade with a size of about 200mm and a weight of about 50g; the lightweight aperture blade 3 made of aluminum alloy or plastic is installed on the rotating shaft 20 of the steering gear 1. The steering gear 1 receives the control command of the steering gear angle controller 40 through the control circuit 60. When the steering gear angle controller 40 sends an angle command to the steering gear 30, the rotating shaft 20 drives the aperture blade 10 to rotate together.

[0045] In specific implementation, all the aperture blades 10 and the steering gear 30 have the same structure, only the arrangement positions are different and the angle of the initial 0° corresponding to the horizontal position is different, so that the assembly is quick and convenient.

[0046] The beneficial effects are as follows: since the servo has a small size, a large driving force, and convenient angle control, the method of using the servo blade array can achieve the adjustment of a large aperture diaphragm suitable for a reliable terahertz imaging system with a small size, a light weight, and a simple control method; it can achieve the size adjustment of an aperture diaphragm of hundreds of millimeters, and it is light in size and convenient to adjust. In the field of terahertz imaging, it has a wide range of applications.

[0047] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0048] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An aperture stop adjustment device for a terahertz imaging system, characterized in that: It includes: Multiple aperture blades, each with an integrated rotation connection point; Multiple servos; A steering gear angle controller; Each servo is arranged one by one corresponding to the aperture blades, and the rotating connection points are connected through the rotating shaft of the servo. All the rotating shafts are arranged in a circular array on the periphery of the equivalent circle center and arranged at intervals. All the servos are fixed on the corresponding fixed object, and the center of the fixed object is hollowed out. The steering gear angle controller is connected to the control input end of each steering gear through a line; the steering gear angle controller controls each steering gear to rotate the output shaft at the same angle and the same rotation direction; In the initial position, the output angle of each servo is 0°, and the central area is closed, that is, the aperture stop is 0. The partial surface area of ​​one end of any aperture blade away from the rotation axis blocks the partial surface area of ​​the corresponding end of the adjacent aperture blade, and the end of each aperture blade away from the rotation axis covers the center of the aperture stop. All aperture blades and servos have the same structure, only the arrangement positions and the initial 0° angle corresponding to the horizontal position are different.

2. The aperture stop adjustment device of the terahertz imaging system according to claim 1, characterized in that: The servos are all arranged on the back side areas of the aperture blades, and the rotation axis does not protrude from the aperture blades.

3. The aperture stop adjustment device of the terahertz imaging system according to claim 2, characterized in that: Each of the aperture blades includes a large arc end edge, a small arc end edge, a first arc transition edge, and a second arc transition edge. The rotation axis is arranged close to the large arc end edge, and the small arc end edge is arranged away from the rotation axis. The two sides of the large arc end edge are connected to the corresponding sides of the small arc end edge through the first arc transition edge and the second arc transition edge respectively.

4. A method for adjusting the aperture stop of a terahertz imaging system, which uses the aperture stop adjusting device of a terahertz imaging system as claimed in any one of claims 1 to 3, characterized in that: It combines multiple aperture blades to form a fan blade structure with a closed central area in a closed state. Each aperture blade is provided with a rotation connection point on the periphery. The rotation shaft of a single servo is fixedly connected to the rotation connection point of the corresponding aperture blade. The array angle of the aperture blades is synchronously controlled by the same servo angle controller to achieve synchronous movement of each aperture blade, thereby changing the size of the aperture aperture in the central area corresponding to the fan blade structure.

5. The method for adjusting the aperture stop of a terahertz imaging system according to claim 4, characterized in that: In the initial position, the output angle of each servo is 0°, and the central area is closed, that is, the aperture diaphragm is 0. The partial surface area of ​​one end of any aperture blade away from the rotation axis blocks the partial surface area of ​​the corresponding end of the adjacent aperture blade, and the end of each aperture blade away from the rotation axis covers the center of the aperture diaphragm to ensure a closed arrangement of the central area.

6. The method for adjusting the aperture stop of a terahertz imaging system according to claim 4, characterized in that: The output angle of the servo angle controller for each servo is synchronously rotated clockwise or counterclockwise, ensuring that the aperture diaphragm is synchronously increased or decreased through the rotation of multiple diaphragm blades.

7. The method for adjusting the aperture stop of a terahertz imaging system according to claim 4, characterized in that: When the output angle of the servo angle controller driving the servo is 90°, the size of the aperture diaphragm reaches its maximum. When the output angle is greater than 90°, the partial surface area of ​​the end of the diaphragm blade away from the rotation axis cannot cover the corresponding end of the adjacent diaphragm blade, making the entire central area a non-closed surface area and unable to operate normally.

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