Focusing imaging assembly

Abstract

The invention discloses a focus-adjustable imaging assembly, and relates to the technical field of optical devices. Comprising a focusing assembly, a zooming assembly and a fixing assembly. A focusing motor drives a focusing cam to rotate through a first gear, so that a first curve guide groove drives a focusing guide nail to slide in a guide groove formed in a guide cylinder in a chiseled mode, a focusing lens set is driven to move in the guide cylinder in the axial direction, and focusing of the focus-adjustable imaging assembly is achieved. The zoom motor drives the zoom cam to rotate through the second gear, so that the second curve guide groove drives the zoom guide nail to slide in a guide groove formed in the guide cylinder in a chiseled mode, the zoom lens set is driven to move in the guide cylinder in the axial direction, and zoom of the focus-adjustable imaging assembly is achieved. The zooming cam and the focusing cam are respectively driven by the zooming motor and the focusing motor, and the zooming displacement control and the focusing displacement control are mutually independent and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of optical components, and particularly relates to an adjustable-focus imaging component. Background Art

[0002] An adjustable-focus imaging component is a high-performance optical device, which is widely used in various imaging systems, such as machine vision, infrared thermal imaging and other fields. By adjusting the focal length, users can clearly observe targets at different distances and obtain more accurate image data. The adjustable-focus imaging component can achieve precise focal length adjustment and is an ideal choice for scientific research, industrial inspection and other fields.

[0003] In the prior art, an adjustable-focus imaging component is composed of core components such as an adjustable-focus lens system, an imaging sensor, a control circuit and a lens focusing mechanism. Among them, the adjustable-focus lens system includes at least one lens whose position is adjusted electrically; the imaging sensor is responsible for capturing the light focused by the lens system and converting it into an electrical signal to form a digital image; the control circuit is responsible for receiving user instructions; a gear set is used as a linkage mechanism, and the lens focusing mechanism is driven to operate by a motor driving the linkage mechanism to achieve focusing; and the digital image output by the imaging sensor is processed to obtain a clear digital image.

[0004] In the process of realizing focusing in the existing adjustable-focus imaging component, the motor controls zooming and focusing simultaneously through the linkage mechanism. In the transmission process, gear errors or elastic deformations will occur in the linkage mechanism, resulting in mutual interference between zooming and focusing movements, and the deviation between the actual displacement of the lens focusing mechanism and the theoretical value is relatively large, especially when starting and stopping frequently, the error accumulation is obvious. Summary of the Invention

[0005] Based on this, it is necessary to provide an adjustable-focus imaging component for the above technical problems.

[0006] An embodiment of the present invention provides an adjustable-focus imaging component, including: a focusing component, a zooming component, and a fixing component for connecting the focusing component and the zooming component; The fixing component includes a guiding cylinder, and a guiding groove parallel to the optical axis is chiseled in the guiding cylinder; The focusing component includes: a focusing lens group, a focusing cam, a focusing guiding nail and a focusing motor, and the focusing motor is electrically connected to the focusing cam; the focusing cam is sleeved on one end of the guiding cylinder, and the focusing lens group is arranged inside the guiding cylinder; a first curve guiding groove is chiseled in the focusing cam; one end of the focusing guiding nail is fixedly connected to the focusing lens group, and the focusing guiding nail is slidably connected to the guiding groove and the first curve guiding groove; Zoom component, comprising: a zoom lens group, a zoom cam, a zoom guide pin and a zoom motor, the zoom motor being electrically connected to the zoom cam; the zoom cam is sleeved on the other end of the guide tube, and the zoom lens group is disposed inside the guide tube; the zoom cam is provided with a second curve guide groove; one end of the zoom guide pin is fixedly connected to the zoom lens group, and the zoom guide pin is slidably connected to the guide groove and the second curve guide groove; The focusing motor drives the focusing cam to rotate through a first gear, so that the first curve guide groove drives the focusing guide pin to slide in the guide groove formed in the guide tube, so as to drive the focusing lens group to move axially inside the guide tube, realizing the focusing of the adjustable focusing imaging component; The zoom motor drives the zoom cam to rotate through a second gear, so that the second curve guide groove drives the zoom guide pin to slide in the guide groove formed in the guide tube, so as to drive the zoom lens group to move axially inside the guide tube, realizing the zoom of the adjustable focusing imaging component.

[0007] Optionally, the fixing component further comprises: a bottom plate, a front fixing plate and a rear fixing plate; the front fixing plate is fixedly connected to one side of the bottom plate close to the focusing cam, and the front fixing plate is fixedly connected to the focusing motor; the rear fixing plate is fixedly connected to the side of the bottom plate away from the focusing cam; One end of the guide tube where the focusing cam is disposed outside is also fixedly connected to a zoom lens, the zoom lens is supported and fixed by the front fixing plate and the rear fixing plate, and the zoom motor is fixedly connected to the bottom plate.

[0008] Optionally, a first micro switch is provided on one side of the front fixing plate close to the focusing component, and a second micro switch is provided on one side of the front fixing plate close to the zoom component; a first limit pin is installed in the slide rail formed in the focusing cam, and a second limit pin is installed in the slide rail formed in the zoom cam; During the zooming process, when the first limit pin contacts the first micro switch, a first limit signal is sent out, and the zoom motor stops rotating, stopping the zooming; during the focusing process, when the second limit pin contacts the second micro switch, a second limit signal is sent out, and the focusing motor stops rotating, stopping the focusing.

[0009] Optionally, the rear fixing plate is further provided with a detection plate component fixing hole for connecting the detection plate component and a control plate component fixing hole for connecting the control plate component; The detection plate component comprises: a fixing seat, a filter, a detection plate and an adjustment gasket; the filter is glued to the fixing seat, the detection plate is fixedly connected to the fixing seat, and the adjustment gasket is arranged between the detection plate and the fixing seat; The control plate component comprises: a heat dissipation plate, a main control board, a fixing plate and a motor control board; the main control board is fixedly connected to one side of the fixing plate, and the other side of the fixing plate is fixedly connected to the motor control board; a heating device is provided on the main control board, and a heat dissipation plate is provided above the heating device, and a heat dissipation silica gel pad is provided between the heat dissipation plate and the heating device.

[0010] Optionally, nylon spacer columns for insulation are provided between the main control board and the heat dissipation board, between the main control board and the fixing board, and between the motor control board and the fixing board.

[0011] Optionally, the zoom component further includes: a zoom cam retaining ring and a compensation group guide pin, and the focusing component further includes a focusing cam retaining ring; The focusing cam is sleeved on one end of the guide tube through the focusing cam retaining ring, and the zoom cam is sleeved on the other end of the guide tube through the zoom cam retaining ring; A third curve guide groove is also chiseled at one end of the zoom cam close to the zoom cam retaining ring; one end of the compensation group guide pin is fixedly connected to the zoom lens group, and the compensation group guide pin is slidably connected to the guide groove and the third curve guide groove chiseled on the guide tube; during the zooming process, the zoom motor drives the zoom cam to rotate, so that the third curve guide groove drives the compensation group guide pin to slide in the guide groove chiseled on the guide tube, driving the compensation lens group to move axially inside the guide tube to compensate for the image plane change caused by the movement of the zoom lens group.

[0012] Optionally, a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group are sequentially arranged inside the guide tube, and further include a plurality of spacer rings and a plurality of lens retaining rings; The fifth lens group is a focusing lens group, the fourth lens group is a zoom lens group, the third lens group is a first fixed lens group, the second lens group is a compensation lens group, and the first lens group is a second fixed lens group; The target object sequentially passes through the fifth lens group, the fourth lens group, the third lens group, the second lens group, and the first lens group to form a visible image at the final imaging position; during the zooming process, the image plane change caused by the movement of the fourth lens group is compensated by the second lens group; Spacer rings are arranged inside the guide tube at fixed intervals of each lens group, and the lenses in each lens group are fixed and positioned through the lens retaining rings.

[0013] Optionally, a diaphragm assembly is provided on one side of the third lens group, and the diaphragm assembly includes a variable diaphragm, a diaphragm drive gear, and a diaphragm drive motor; The diaphragm drive motor drives the variable diaphragm to rotate through the diaphragm drive gear to adjust the aperture size of the variable diaphragm to achieve the continuous dimming function; A first micro switch and a second micro switch are respectively provided on both sides of the variable diaphragm, and the diaphragm lever of the variable diaphragm is used as a limit lever; When the variable diaphragm rotates to the two extreme limit positions, the limit lever contacts the first micro switch or the second micro switch, sending a third limit signal, and the diaphragm drive motor stops rotating.

[0014] The above adjustable focusing imaging component provided by the embodiments of the present invention has the following beneficial effects compared with the prior art: In the present invention, the zoom cam and the focus cam are respectively driven by a zoom motor and a focus motor. The displacement control of zooming and focusing is independent and precise, which can avoid gear errors or elastic deformations in the linkage structure during the transmission process. By combining the cam and the guide pin, the mapping relationship between the displacement of the lens group and the rotation angle of the cam is uniquely determined by the cam curve, directly transmitting the mapping relationship between the rotation angle of the cam and the displacement of the lens group, realizing precise mechanical transmission, and being able to solve the problem that the actual displacement of the lens focusing mechanism in the prior art has a large deviation from the theoretical value, and avoiding cumulative errors during frequent start-stop processes. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the overall structure of an adjustable-focus imaging component provided in an embodiment; Figure 2 It is a dimension diagram of the whole machine of an adjustable-focus imaging component provided in an embodiment; Figure 3 It is a schematic diagram of the zoom lens of an adjustable-focus imaging component provided in an embodiment; Figure 4 It is a schematic diagram of the inside of the zoom lens of an adjustable-focus imaging component provided in an embodiment; Figure 5 It is a schematic diagram of lens group 1 of an adjustable-focus imaging component provided in an embodiment; Figure 6 It is a dimension diagram of the zoom lens of an adjustable-focus imaging component provided in an embodiment; Figure 7 It is a schematic diagram of the diaphragm component structure of an adjustable-focus imaging component provided in an embodiment; Figure 8 It is a schematic diagram of the whole-machine mounting circuit board of an adjustable-focus imaging component provided in an embodiment; Figure 9 It is a dimension diagram of the whole-machine mounting circuit board of an adjustable-focus imaging component provided in an embodiment; Figure 10 It is a schematic diagram of the detection board component structure of an adjustable-focus imaging component provided in an embodiment; Figure 11 It is a structure diagram of the detection board component of an adjustable-focus imaging component provided in an embodiment; Figure 12 It is an optical system diagram of an adjustable-focus imaging component with a focal length of 15 mm provided in an embodiment; Figure 13 It is an optical system diagram of an adjustable-focus imaging component with a focal length of 40 mm provided in an embodiment; Figure 14 It is an optical system diagram of an adjustable-focus imaging component with a focal length of 160 mm provided in an embodiment; Figure 15 Optical system diagram of a 240mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 16 Optical system diagram of a 300mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 17 Vertical chromatic aberration diagram of a 15mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 18 Vertical chromatic aberration diagram of a 40mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 19 Vertical chromatic aberration diagram of a 160mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 20 Vertical chromatic aberration diagram of a 240mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 21 Vertical chromatic aberration diagram of a 300mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 22 Longitudinal chromatic aberration diagram of a 15mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 23 Longitudinal chromatic aberration diagram of a 40mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 24 Longitudinal chromatic aberration diagram of a 160mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 25 Longitudinal chromatic aberration diagram of a 240mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 26 Longitudinal chromatic aberration diagram of a 300mm focal length for an adjustable focus imaging component provided in an embodiment; Figure 27 MTF diagram before focusing for an adjustable focus imaging component provided in an embodiment; Figure 28 MTF diagram after focusing for an adjustable focus imaging component provided in an embodiment.

[0016] Wherein: 1. Bottom plate; 2. Rear fixing plate; 3. Wire outlet; 4. Fixed holes for detection plate assembly; 5. Fixed holes for control plate assembly; 6. Focus motor; 7. Focus guiding pin; 8. First microswitch; 9. Zoom lens; 10. First limit pin; 11. Focus cam; 12. Front fixing plate; 13. Zoom guiding pin; 14. Zoom cam; 15. Zoom motor; 16. Second microswitch; 17. Second limit pin; 911. Guide tube; 912. Zoom cam retaining ring; 913. Compensation group guiding pin; 914. Focus cam retaining ring; 921. Lens group one; 922. Lens group two; 923. Lens group three; 924. Lens group four; 925. Lens group five; 926. Lens retaining ring; 927. Spacer ring; 928. Steel ball; 929. Diaphragm assembly; 101. Detection plate assembly; 102. Control plate assembly; 103. Flexible cable; 21. Fixed seat; 22. Filter; 23. Adjusting gasket; 24. Detection plate; 31. Heat dissipation plate; 32. Main control board; 33. Nylon spacer post; 34. Fixing plate; 35. Motor control board; 41. Limit rod; 42. Variable diaphragm; 43. Diaphragm driving motor; 44. Diaphragm driving gear; 51. Main barrel of lens group one; 52. Lens frame; 53. Lens; 54. Lens frame retaining ring. Detailed implementation mode

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] In one embodiment, a focus-adjustable imaging component is provided, and the component includes: a focusing component, a zooming component, and a fixing component for connecting the focusing component and the zooming component.

[0019] The fixing component includes a guide tube 911, and the guide tube 911 is provided with a guide groove parallel to the optical axis.

[0020] The focusing component includes: a focusing lens group, a focus cam 11, a focus guiding pin 7, and a focus motor 6. The focus motor 6 is electrically connected to the focus cam 11. The focus cam 11 is sleeved on one end of the guide tube 911, and the focusing lens group is arranged inside the guide tube 911. The focus cam 11 is provided with a first curve guide groove. One end of the focus guiding pin 7 is fixedly connected to the focusing lens group, and the focus guiding pin 7 is slidably connected to the guide groove and the first curve guide groove.

[0021] Zoom component, including: zoom lens group, zoom cam 14, zoom guiding pin 13 and zoom motor 15, the zoom motor 15 is electrically connected to the zoom cam 14. The zoom cam 14 is sleeved on the other end of the guiding cylinder 911, and the zoom lens group is arranged inside the guiding cylinder 911. The zoom cam 14 is chiseled with a second curve guiding groove. One end of the zoom guiding pin 13 is fixedly connected to the zoom lens group, and the zoom guiding pin 13 is slidably connected to the guiding groove and the second curve guiding groove.

[0022] The focusing motor 6 drives the focusing cam 11 to rotate through the first gear, so that the first curve guiding groove drives the focusing guiding pin 7 to slide in the guiding groove chiseled in the guiding cylinder 911, so as to drive the focusing lens group to move axially inside the guiding cylinder 911, realizing the focusing of the adjustable focusing imaging component.

[0023] The zoom motor 15 drives the zoom cam 14 to rotate through the second gear, so that the second curve guiding groove drives the zoom guiding pin 13 to slide in the guiding groove chiseled in the guiding cylinder 911, so as to drive the zoom lens group to move axially inside the guiding cylinder 911, realizing the zoom of the adjustable focusing imaging component.

[0024] The diaphragm driving motor 43 drives the diaphragm driving gear 44 to drive the variable diaphragm 42 to rotate, so as to adjust the aperture size of the variable diaphragm 42 to realize the continuous dimming function. The first microswitch 8 and the second microswitch 16 are respectively arranged at two extreme positions of the rotation of the cam and the diaphragm gear. The first limit signal is sent during the zooming process, the second limit signal is sent during the focusing process, and the third limit signal is sent during the continuous dimming process, which are used to limit the rotation range of the motor and prevent the motor from jamming.

[0025] As Figure 1 shown, the fixing component further includes: a bottom plate 1, a front fixing plate 12 and a rear fixing plate 2; one side of the bottom plate 1 close to the focusing cam 11 is fixedly connected to the front fixing plate 12, and the front fixing plate 12 is fixedly connected to the focusing motor 6. The side of the bottom plate 1 away from the focusing cam 11 is fixedly connected to the rear fixing plate 2. The zoom lens 9 is supported and fixed by the front fixing plate 12 and the rear fixing plate 2, and the zoom motor 15 is fixedly connected to the bottom plate 1.

[0026] A first microswitch 8 is arranged on one side of the front fixing plate 12 close to the focusing component, and a second microswitch 16 is arranged on one side of the front fixing plate 12 close to the zoom component; a first limit pin 10 is installed in the chiseled slide rail of the focusing cam 11, and a second limit pin 17 is installed in the chiseled slide rail of the zoom cam 14. During the zooming process, when the first limit pin 10 contacts the first microswitch 8, a first limit signal is sent, and the zoom motor 15 stops rotating and stops zooming; during the focusing process, when the second limit pin 17 contacts the second microswitch 16, a second limit signal is sent, and the focusing motor 6 stops rotating and stops focusing.

[0027] An outlet 3 is opened on the rear fixing plate 2 to lead out the diaphragm driving motor 43 and the microswitch wires. The rear fixing plate 2 is also provided with a fixing hole 4 for the detection plate assembly for connecting the detection plate assembly 101 and a fixing hole 5 for the control plate assembly for connecting the control plate assembly 102. The overall dimensions of the whole machine are as Figure 2 shown, with an overall length of 217.8×width of 91×height of 78.

[0028] The zoom assembly further includes a zoom cam retaining ring 912 and a compensating group guide pin 913, and the focusing assembly further includes a focusing cam retaining ring 914. The focusing cam 11 is sleeved on one end of the guide tube 911 through the focusing cam retaining ring 914, and the zoom cam 14 is sleeved on the other end of the guide tube 911 through the zoom cam retaining ring 912. The zoom cam 14 is also chiseled with a third curve guide groove at one end close to the zoom cam retaining ring 912; one end of the compensating group guide pin 913 is fixedly connected to the zoom lens group, and the compensating group guide pin 913 is slidably connected to the guide groove and the third curve guide groove chiseled on the guide tube 911. During the zooming process, the zoom motor 15 drives the zoom cam 14 to rotate, so that the third curve guide groove drives the compensating group guide pin 913 to slide in the guide groove chiseled on the guide tube 911, driving the compensating lens group to move axially inside the guide tube 911 to compensate for the image plane change caused by the movement of the zoom lens group.

[0029] I. Structural layout design The lens group layout is as Figure 3 and Figure 4 shown. Inside the guide tube 911, there are successively a lens group one 921, a lens group two 922, a lens group three 923, a lens group four 924 and a lens group five 925. The lens group one 921 is the second fixed lens group, the lens group two 922 is the compensating lens group, the lens group three 923 is the first fixed lens group, the lens group four 924 is the zoom lens group, and the lens group five 925 is the focusing lens group. There are also a plurality of spacer rings 927 and a plurality of lens retaining rings 926.

[0030] The lens group five 925 is composed of 4 lenses (including 2 cemented lenses) for focusing; the lens group four 924 is composed of 4 lenses (including 2 cemented lenses) for zooming; the lens group three 923 is located in the middle of the lens, composed of 3 lenses (including 2 cemented lenses) and an adjustable diaphragm; the lens group two 922 is composed of a cemented lens for compensating the image plane change caused by the movement of the lens group four 924; the lens group one 921 includes 5 lenses and 1 filter 22.

[0031] The target object successively passes through the lens group five 925, the lens group four 924, the lens group three 923, the lens group two 922 and the lens group one 921, and a visible image is formed at the final imaging position. During the zooming process, the image plane change caused by the movement of the lens group four 924 is compensated by the lens group two 922.

[0032] Spacer rings 927 are arranged inside the guiding cylinder 911 at fixed intervals for each lens group, and the lenses in each lens group are fixed and positioned by lens retaining rings 926.

[0033] The focusing cam 11 and the zoom cam 14 are respectively fixed to the guiding cylinder 911 with threaded retaining rings, and steel balls 928 with a diameter of 1 mm are installed at both ends of the focusing cam 11 and the zoom cam 14 to ensure smooth rotation of the cams. There are guiding grooves parallel to the optical axis on the guiding cylinder 911, and curved guiding grooves on the cams. A focusing guiding pin 7 is provided on the focusing cam 11, and a compensating group guiding pin 913 and a zoom guiding pin 13 are provided on the zoom cam 14. The guiding pins slide in the guiding grooves of the guiding cylinder 911 and the cams at the same time. When the zoom cam 14 rotates, it drives the zoom guiding pin 13 and the compensating group guiding pin 913 to move along the optical axis direction at the same time to achieve zooming. When the focusing cam 11 rotates, it drives the focusing guiding pin 7 to move along the optical axis direction to achieve focusing.

[0034] To meet the requirements of optical axis consistency, the coaxiality error of the lenses in the lens group should be within 0.01 mm, the interval error should be within 0.02 mm, the coaxiality error between lens groups should be within 0.02 mm, and the interval error of the lens groups should be within 0.02 mm.

[0035] To ensure the installation accuracy requirements of the lenses in the lens group, a centering assembly process structure is adopted. Taking the structure of lens group one 921 as an example, as Figure 5 shown, multiple lens elements 53 are first installed into the lens frame 52, then the lens frame 52 is subjected to optical centering processing, and then installed into the main lens barrel 51 of lens group one. Spacer rings 927 are provided inside the lens frame 52 at fixed intervals, and a lens frame retaining ring 54 is provided. The fit tolerance between each lens element 53 and the lens frame 52 is H7 / f7. The large clearance is good for assembly. Each lens element 53 is positioned with a lens retaining ring 926. Glue dots are required for both the lens retaining ring 926 and the lens element 53 to ensure reliable fixation of the lens element 53. The coaxiality tolerance between the outer circle of the optically centered lens frame 52 and the optical axis of the lens element 53 is Φ0.005 mm, the perpendicularity tolerance between the axial positioning surface of the lens frame 52 and the optical axis of the lens element 53 is 0.005 mm, and the diameter clearance between the lens frame 52 and the main lens barrel 51 of lens group one is required to be less than 0.008 mm, which can control the coaxiality error of the lens elements 53 in lens group one 921 within 0.01 mm, and the interval error of the lens elements 53 is ensured to be within 0.02 mm by trimming and adjusting the thickness of the spacer ring 927.

[0036] To ensure the installation accuracy requirements of the lenses between the lens groups, the outer circle of the main lens barrel of each lens group is adapted to the inner hole of the guide barrel 911, and the diameter clearance requirement is less than 0.008 mm. Through comprehensive calculation, the coaxiality between the lens groups can be controlled within 0.02 mm. There is also a spacer 927 for interval adjustment between the lens groups. By trimming the thickness of the spacer 927, the interval error of the lenses can be ensured within 0.02 mm. The accuracy requirements of the above structure can meet the requirements of the optical system and ensure that the optical axis consistency during the focusing process meets the technical requirements. The lenses are fixed to the lens frame 52 and the lens frame 52 is fixed to the main lens barrel with glue to improve the anti-vibration stability. The external dimensions of the zoom lens 9 are as Figure 6 shown, with a length of 212.8 × width of 78 × height of 78, meeting the design requirements.

[0037] The structure of the diaphragm assembly 929 is as Figure 7 shown. The diaphragm assembly 929 includes a variable diaphragm 42, a diaphragm drive gear 44, and a diaphragm drive motor 43. The adjustment range of the diaphragm aperture is Φ1 mm to Φ12 mm. The motor gear drive is used to drive the adjustable diaphragm to rotate to adjust the size of the diaphragm hole to achieve the continuous dimming function. The diaphragm drive motor 43 drives the diaphragm drive gear 44 to drive the variable diaphragm 42 to rotate, so as to adjust the size of the diaphragm hole of the variable diaphragm 42 to achieve the continuous dimming function. A first microswitch 8 and a second microswitch 16 are respectively arranged on both sides of the variable diaphragm 42, and the diaphragm lever of the variable diaphragm 42 is used as the limit lever 41. When the variable diaphragm 42 rotates to the two extreme limit positions, the limit lever 41 contacts the first microswitch 8 or the second microswitch 16 (when rotating to the left extreme limit position, the limit lever 41 contacts the first microswitch 8; when rotating to the right extreme limit position, the limit lever 41 contacts the second microswitch 16), sending a third limit signal, and the diaphragm drive motor 43 stops rotating. The entire assembly is fixed to the guide barrel 911 with three screws. Motor avoidance holes are processed on the guide barrel 911, the main lens barrel of the second lens group, and the main lens barrel 51 of the first lens group to facilitate installation and wiring. The wires of the motor and the microswitch are led out from the rear fixing plate 2.

[0038] II. Selection of the drive assembly To achieve miniaturized design, the size of the motor should be as small as possible. Therefore, a coreless motor with a reduction gearbox and an encoder is selected as the drive assembly, and the microswitch is used for limiting. According to the requirement that the field of view change time ≤ 6 s, the rotation speed of the zoom cam 14 is calculated by combining the winding angle of the zoom cam 14 curve. The rotation speed of the focusing cam 11 is calculated from the focusing time (set as 1 s) and the winding angle of the focusing cam 11 curve, and then the rotation speed of the drive assembly is calculated in combination with the gear transmission ratio. The moving speed of each moving lens group is calculated from the rotation speed of the cam and the pressure angle of the cam curve. Considering factors such as the mass of the moving lens group, the mass of the cam, the friction coefficient between the structural parts, and the transmission efficiency, the torque of the drive assembly is calculated. It is calculated that the output torque of the zoom drive assembly should be greater than 200 mN·m and the rotation speed should be greater than 30 r / min.

[0039] Adjust the time (set to 1 s) and the rotation angle range by the variable aperture 42, and then calculate the rotational speed of the drive assembly in combination with the gear transmission ratio. According to the rotational torque of the variable aperture 42 (less than 20 mN·m), calculate the torque of the drive assembly by combining factors such as the gear transmission ratio, the friction coefficient between structural components, and the transmission efficiency. It is calculated that the output torque of the aperture drive assembly should be greater than 50 mN·m and the rotational speed should be greater than 60 r / min.

[0040] III. Structural Layout of the Whole Machine with the Circuit Board Assembly Installed After the detection board assembly 101 and the control board assembly 102 are installed on the whole machine, the structure is as Figure 8 and Figure 9 shown. The detection board 24 is connected to the control board through a flexible cable 103. The overall length of the camera board with the addition is 249.5×width 954×height 78.

[0041] The structure of the detection board assembly 101 is as Figure 10 shown. The detection board assembly 101 includes: a fixed seat 21, a filter 22, a detection board 24, and an adjustment gasket 23 arranged between the detection board 24 and the fixed seat 21; the filter 22 is adhesively bonded to the fixed seat 21, and the detection board 24 is fixedly connected to the fixed seat 21.

[0042] The filter 22 is bonded to the fixed seat 21 with GD414 silicone rubber. There is an adjustment gasket 23 between the detection board 24 and the fixed seat 21. By replacing the adjustment gaskets 23 with different thicknesses, the optical axis direction position of the detection board 24 is adjusted to make the image clear. The detection board 24 is fixed to the fixed seat 21 with four screws. The detection board 24 only contacts the fixed seat 21 at the fixing holes. The fixing holes of the detection board 24 are not connected to the power ground. The adjustment gasket 23 is made of hard aluminum material and is anodized on the surface, which is non-conductive and can ensure the insulation between the CMOS camera and the fixed seat 21.

[0043] The structure of the control board assembly 102 is as Figure 11 shown. The control board assembly 102 includes: a heat dissipation board 31, a main control board 32, a fixing board 34, and a motor control board 35; the main control board 32 is fixedly connected to one side of the fixing board 34, and the other side of the fixing board is fixedly connected to the motor control board 35; there are heat generating devices on the main control board 32, and a heat dissipation board 31 is arranged above the heat generating devices, and a heat dissipation silicone pad is arranged between the heat dissipation board 31 and the heat generating devices. Nylon spacers 33 for insulation are arranged between the main control board 32 and the heat dissipation board 31, between the main control board 32 and the fixing board 34, and between the motor control board 35 and the fixing board 34.

[0044] There are heat-generating components on the main control board 32. A heat sink 31 is installed above them. A heat-conducting silicone pad with a high thermal conductivity coefficient is pasted between the heat sink 31 and the heat-generating components. The heat sink 31 and the main control board 32 are fixed to the fixing plate 34 together. The motor control board 35 is fixed to the back of the fixing plate 34. Nylon spacers 33 are used for insulation between the main control board 32 and the heat sink 31, between the main control board 32 and the fixing plate 34, and between the motor control board 35 and the fixing plate 34.

[0045] IV. Component Evaluation 1. Optical Design Results The main optical parameters at each focal length position of the optical system are shown in Table 1.

[0046] Table 1 Main Parameters of the Optical System

[0047] Five configurations are set for design optimization, with focal lengths of 15 mm (as shown in Figure 12 ), 40 mm (as shown in Figure 13 ), 160 mm (as shown in Figure 14 ), 240 mm (as shown in Figure 15 ), and 300 mm (as shown in Figure 16 ), and the maximum clear aperture is 43 mm. 2. Transmittance Calculation

[0048] The completed continuously variable zoom optical system uses a total of 19 lenses. If a 450 nm - 650 nm all-dielectric broadband antireflection coating is deposited on the 38 lens surfaces of the entire optical system, with an average transmittance of 99.5%, the material absorption rate is calculated as 0.008 attenuation per centimeter, and the total glass thickness is 7.2 cm, then the theoretical calculated value of the transmittance τ of the lens is: ; 3. Imaging Quality Evaluation A. Field Curvature and Distortion When the optical system is working, the designed value of the full-field distortion is less than 5%.

[0049] B. Modulation Transfer Function Curve The modulation transfer function (MTF) reflects the transfer ability of the optical system to different frequency components of an object. Generally speaking, the high-frequency part reflects the transfer of object details, the middle-frequency part reflects the transfer of object levels, and the low-frequency part reflects the transfer of object contours. MTF reflects the attenuation degree of the contrast after the sine intensity distribution function of various different frequencies is imaged by the optical system.

[0050] C. Aberration Curve The ray aberration curve is a means of evaluating an optical system based on geometric optical ray tracing, which can comprehensively and qualitatively evaluate various primary and higher-order monochromatic aberrations and various chromatic aberrations of the entire optical system. By evaluating the ray aberrations at each zoom position of the optical system, the aberration characteristics of the entire optical system can be comprehensively analyzed and grasped, and the aberration distribution of the actual optical system imaging can be predicted.

[0051] D. Spot diagram In the imaging process of an actual optical system, due to the existence of aberrations, the light rays emitted from a point, after passing through the optical system and imaging, do not converge at a single point on the image plane, but form a diffuse pattern distributed within a certain range, which is called a spot diagram. The spot diagram measures the imaging quality of the optical system by the density of the light points on the image plane. The diffraction limit of an optical system is usually measured by the radius r of the Airy disk, and the calculation formula for the radius r of the Airy disk is as follows: r = 1.22λ / F where, λ — the main wavelength of the optical system, the highest point of the detector quantum efficiency, taking 0.588 μm; F — the aperture value of the optical system (F-number, also known as the F number or focal ratio); It can be seen from the above formula that the radius of the Airy disk is only determined by the wavelength and the aperture value.

[0052] E. Lateral chromatic aberration Lateral chromatic aberration, also known as magnification chromatic aberration, is an aberration caused by different magnifications due to different focal lengths of different wavelengths. The magnification chromatic aberration makes the edges of the object image show colors and affects the imaging clarity. The aberration sizes within the field of view of each focal segment of this system are all smaller than the Airy disk size and will not affect the imaging. As Figure 17 、 Figure 18 、 Figure 19 、 Figure 20 and Figure 21 shown, Figure 17 is the lateral chromatic aberration diagram for 15 mm, the short wavelength is 0.4500 μm, and the long wavelength is 0.6563 μm; Figure 18 is the lateral chromatic aberration diagram for 40 mm, the short wavelength is 0.4500 μm, and the long wavelength is 0.6563 μm; Figure 19 is the lateral chromatic aberration diagram for 160 mm, the short wavelength is 0.4500 μm, and the long wavelength is 0.6563 μm; Figure 20 is the lateral chromatic aberration diagram for 240 mm, the short wavelength is 0.4500 μm, and the long wavelength is 0.6563 μm; Figure 21 is the lateral chromatic aberration diagram for 300 mm, the short wavelength is 0.4500 μm, and the long wavelength is 0.6563 μm.

[0053] F. Longitudinal chromatic aberration The axial chromatic aberration is the chromatic aberration of the focal position caused by the different focal lengths of the compound light with different wavelengths passing through the optical system, also known as the position chromatic aberration. The position chromatic aberration occurs in the paraxial region. Different focal positions will produce a chromatic dispersion spot. The shape, size, and energy concentration of the dispersion spot are all reflected in the point spread function diagram in d). It has been corrected, and the focal shift distance does not directly affect the imaging quality. As Figure 22 , Figure 23 , Figure 24 , Figure 25 and Figure 26 shown, Figure 22 is the axial chromatic aberration diagram of 15mm. The maximum focal length change is 63.1880μm, and the diffraction limit change is 75.217μm; Figure 23 is the axial chromatic aberration diagram of 40mm. The maximum focal length change is 85.6085μm, and the diffraction limit change is 87.130μm; Figure 24 is the axial chromatic aberration diagram of 160mm. The maximum focal length change is 221.3307μm, and the diffraction limit change is 113.664μm; Figure 25 is the axial chromatic aberration diagram of 240mm. The maximum focal length change is 168.6857μm, and the diffraction limit change is 117.979μm; Figure 26 is the axial chromatic aberration diagram of 300mm. The maximum focal length change is 87.5328μm, and the diffraction limit change is 114.361μm.

[0054] 4. Imaging Distance Analysis Using the focusing lens group, focus adjustment is performed when imaging scenes with different object distances. The system focus adjustment amount is +1mm~-1mm (positive for moving towards the object side and negative for moving towards the image side). When the system is in the short focal length (EFL = 15mm) position, the transfer function curves obtained after focusing on an object distance of 20m are as Figure 27 shown, and the transfer function curves obtained after focusing on an object distance of 20m are as Figure 28 shown. From the comparison between Figure 27 and Figure 28 , it can be seen that when the object distance is 20m, the image quality does not significantly decrease, and clear imaging can be achieved after moving the focusing lens group.

[0055] 5. Image Plane Consistency Analysis During the design process of the optical system, the image plane remains fixed (the distance between the surface of the lens closest to the image plane on the outermost side of the optical system and the focal plane is constant). Therefore, in the short and long focal lengths of the designed system, the focal plane always remains fixed. This ensures that the imaging component can be focused clearly at any position during the zooming process, and the image is clear and free of dirt spots during the zooming process.

[0056] 6. Environmental Adaptability Analysis The influence of ambient temperature on the optical system is mainly manifested in the influence on the characteristics of optical materials and the external dimensions of mechanical structural parts. For the former, generally, the change in ambient temperature will affect the external dimensions of optical components, such as the radius of curvature, thickness, outer diameter, etc., resulting in a decline in the performance of the optical system; the change in ambient temperature will also cause a change in the refractive index of the material, making the optical path of the imaging beam change, and further leading to a decline in the performance of the optical system. For the latter, when the ambient temperature changes, the mechanical structural parts undergo thermal deformation. When the deformation amount is inconsistent or mismatched with the optical material, it will cause the image plane to be out of focus, directly affecting the imaging quality. However, the final manifestation results of these two aspects can be attributed to the thermal defocus of the optical system caused by the change in ambient temperature. Therefore, it can be compensated by adjusting the focusing lens group.

[0057] The short focal length of this system is athermalized, and the high and low temperatures have no obvious influence on the image quality. The long focal length end uses the focusing function for focusing compensation, which can compensate for the image plane defocus caused by the change in ambient temperature and ensure the imaging quality under different environments, indicating that the designed optical system has good environmental adaptability.

[0058] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A focus-adjustable imaging component, characterized in that: include: A focusing assembly, a zoom assembly, and a fixing assembly for connecting the focusing assembly and the zoom assembly; The fixing assembly comprises a guide cylinder (911), wherein the guide cylinder (911) is provided with a guide groove parallel to the optical axis; The focusing assembly comprises: a focusing lens group, the focusing cam (11), a focusing guide pin (7) and a focusing motor (6), wherein the focusing motor (6) is electrically connected to the focusing cam (11); the focusing cam (11) is externally mounted on one end of the guide tube (911), and the focusing lens group is internally arranged in the guide tube (911); the focusing cam (11) is chiseled with a first curved guide groove; one end of the focusing guide pin (7) is fixedly connected to the focusing lens group, and the focusing guide pin (7) is slidably connected to the guide groove and the first curved guide groove; The zoom assembly comprises: a zoom lens group, the zoom cam (14), a zoom guide pin (13), a compensation group guide pin (913) and a zoom motor (15), wherein the zoom motor (15) is electrically connected to the zoom cam (14); the zoom cam (14) is mounted on the other end of the guide tube (911), and the zoom lens group is arranged inside the guide tube (911); the zoom cam (14) is chiseled with a second curved guide groove; one end of the zoom guide pin (13) is fixedly connected to the zoom lens group, and the zoom guide pin (13) is slidably connected to the guide groove and the second curved guide groove; the zoom cam (14) is further chiseled with a third curved guide groove at one end close to the zoom cam pressure ring (912); one end of the compensation group guide pin (913) is fixedly connected to the zoom lens group, and the compensation group guide pin (913) is slidably connected to the guide groove chiseled on the guide tube (911) and the third curved guide groove.

2. The focus-adjustable imaging assembly according to claim 1, characterized in that: The fixing assembly further comprises: a bottom plate (1), a front fixing plate (12) and a rear fixing plate (2); a side of the bottom plate (1) close to the focusing cam (11) is fixedly connected to the front fixing plate (12), and the front fixing plate (12) is fixedly connected to the focusing motor (6); a side of the bottom plate (1) away from the focusing cam (11) is fixedly connected to the rear fixing plate (2); One end of the focusing cam (11) outside the guide tube (911) is also fixedly connected to a zoom lens (9); the zoom lens (9) is supported and fixed by the front fixing plate (12) and the rear fixing plate (2); and the zoom motor (15) is fixedly connected to the base plate (1).

3. The focus-adjustable imaging assembly according to claim 2, characterized in that: A first micro switch (8) is provided on a side of the front fixing plate (12) close to the focusing assembly, and a second micro switch (16) is provided on a side of the front fixing plate (12) close to the zoom assembly; a first limit pin (10) is installed in a chiseled slide rail of the focusing cam (11), and a second limit pin (17) is installed in a chiseled slide rail of the zoom cam (14); The focusing motor (6) drives the focusing cam (11) to rotate via the first gear, so that the first curved guide groove drives the focusing guide pin (7) to slide in the guide groove chiseled in the guide tube (911), thereby driving the focusing lens group to move axially inside the guide tube (911), thereby achieving focusing of the adjustable focus imaging component; The zoom motor (15) drives the zoom cam (14) to rotate via the second gear, so that the second curved guide groove drives the zoom guide pin (13) to slide in the guide groove chiseled in the guide tube (911), thereby driving the zoom lens group to move axially inside the guide tube (911), thereby realizing zooming of the adjustable focus imaging assembly; During zooming, the zoom motor (15) drives the zoom cam (14) to rotate, so that the third curved guide groove drives the compensation group guide pin (913) to slide in the guide groove chiseled in the guide tube (911), thereby driving the compensation lens group to move axially inside the guide tube (911) to compensate for changes in the image plane caused by the movement of the zoom lens group; During the zooming process, when the first limit pin (10) contacts the first micro switch (8), a first limit signal is issued, and the zoom motor (15) stops rotating, thereby stopping zooming; during the focusing process, when the second limit pin (17) contacts the second micro switch (16), a second limit signal is issued, and the focus motor (6) stops rotating, thereby stopping focusing.

4. The focus-adjustable imaging assembly according to claim 2, characterized in that: The rear fixing plate (2) is further provided with a detection plate assembly fixing hole (4) for connecting the detection plate assembly (101) and a control plate assembly fixing hole (5) for connecting the control plate assembly (102); The detection plate assembly (101) comprises: a fixing seat (21), a filter (22), a detection plate (24) and an adjustment gasket (23); the filter (22) is glued to the fixing seat (21), the detection plate (24) is fixedly connected to the fixing seat (21), and the adjustment gasket (23) is arranged between the detection plate (24) and the fixing seat (21); The control board assembly (102) comprises: a heat sink (31), a main control board (32), a fixing board (34) and a motor control board (35); the main control board (32) is fixedly connected to one side of the fixing board (34), and the other side of the fixing board (34) is fixedly connected to the motor control board (35); a heating device is provided on the main control board (32), the heat sink (31) is provided above the heating device, and a heat dissipation silicone pad is provided between the heat sink (31) and the heating device.

5. The focus-adjustable imaging assembly according to claim 4, characterized in that: Nylon spacers (33) for insulation are provided between the main control board (32) and the heat dissipation plate (31), between the main control board (32) and the fixed plate (34), and between the motor control board (35) and the fixed plate (34).

6. The focus-adjustable imaging assembly according to claim 1, characterized in that: The zoom assembly further comprises: a zoom cam pressure ring (912); and the focus assembly further comprises a focus cam pressure ring (914); The focusing cam (11) is sleeved on one end of the guide tube (911) via the focusing cam pressing ring (914), and the zoom cam (14) is sleeved on the other end of the guide tube (911) via the zoom cam pressing ring (912).

7. The focus-adjustable imaging assembly according to claim 6, characterized in that: The guide cylinder (911) is provided with lens group one (921), lens group two (922), lens group three (923), lens group four (924) and lens group five (925) in sequence, and also includes a plurality of spacers (927) and a plurality of lens pressing rings (926); The lens group five (925) is the focusing lens group, the lens group four (924) is the zoom lens group, the lens group three (923) is the first fixed lens group, the lens group two (922) is the compensation lens group, and the lens group one (921) is the second fixed lens group; The target object passes through the lens group five (925), the lens group four (924), the lens group three (923), the lens group two (922) and the lens group one (921) in sequence to form a visible image at a final imaging position; during the zooming process, the lens group two (922) compensates for image plane changes caused by the movement of the lens group four (924); The spacer ring (927) is arranged inside the guide cylinder (911) at fixed intervals of each lens group, and the lens in each lens group is fixedly positioned by the lens pressing ring (926).

8. The focus-adjustable imaging assembly according to claim 7, characterized in that: An aperture assembly (929) is provided on one side of the lens group three (923), and the aperture assembly (929) comprises a variable aperture (42), an aperture drive gear (44), and an aperture drive motor (43); The iris drive motor (43) drives the variable iris (42) to rotate via the iris drive gear (44) to adjust the iris hole size of the variable iris (42) to achieve a continuous light adjustment function; The first micro switch (8) and the second micro switch (16) are respectively provided on both sides of the variable iris (42), and the iris lever of the variable iris (42) serves as a limit lever (41); When the variable iris (42) rotates to the limit positions at both ends, the limit rod (41) contacts the first micro switch (8) or the second micro switch (16), a third limit signal is issued, and the iris drive motor (43) stops rotating.

Images