Long-wave infrared electric focusing lens and imaging method thereof

Abstract

The application relates to the field of lenses, in particular to a long-wave infrared electric focusing lens and an imaging method thereof. The long-wave infrared electric focusing lens comprises a main lens barrel, a front fixed lens group and a focusing lens group are sequentially arranged in the main lens barrel from left to right along the light incidence direction; the front fixed lens group comprises a positive lens A and a negative lens B which are sequentially arranged from left to right; the focusing lens group is provided with a positive lens C; and a connecting flange is arranged at the right end of the main lens barrel. The lens can realize 100mm fixed focus imaging, and the movement of the focusing group can realize searching and tracking of objects at different distances under different temperatures.

Description

Technical Field

[0001] This invention relates to the field of lenses, specifically to a long-wave infrared motorized focusing lens and its imaging method. Background Technology

[0002] In infrared imaging systems, optical systems with autofocus capabilities can quickly locate and search for objects within a specific distance range. The movement of the focusing group ensures that the image remains focused under varying operating temperatures, enabling rapid target detection, identification, tracking, and aiming. However, there are currently no thermal imaging lenses suitable for forest fire prevention and border / coastal defense applications. Summary of the Invention

[0003] The purpose of this invention is to provide a long-wave infrared motorized focusing lens and its imaging method. The lens can achieve 100mm fixed-focus imaging, and the movement of the focusing group can enable searching and tracking of objects at different distances under different temperatures.

[0004] The technical solution of the present invention is as follows: a long-wave infrared motorized focusing lens, comprising a main lens barrel, wherein a front fixed lens group and a focusing lens group are arranged sequentially from left to right along the incident direction of light in the main lens barrel; the front fixed lens group includes a positive lens A and a negative lens B arranged sequentially from left to right; the focusing lens group is provided with a positive lens C; and a connecting flange is installed on the right side end of the main lens barrel.

[0005] Furthermore, the air gap between the positive lens A and the negative lens B is 38.66 mm, and the air gap between the negative lens B and the positive lens C is 19.54 mm to 27.04 mm.

[0006] Furthermore, the main lens barrel is provided with a first annular stepped surface for abutting the right end periphery of the positive lens A, and an A-plate pressure ring for fixing the positive lens A is screwed into the main lens barrel.

[0007] Furthermore, the main lens barrel is provided with a second annular stepped surface for abutting the right end periphery of the negative lens B, and a B-plate pressure ring for fixing the negative lens B is screwed into the main lens barrel.

[0008] Furthermore, a focusing lens mount is provided inside the main lens barrel, and the positive lens C is installed inside the focusing lens mount. The focusing lens mount is provided with a third annular stepped surface for abutting the right end periphery of the positive lens C. A C-plate retaining ring for fixing the positive lens C is screwed into the focusing lens mount.

[0009] Furthermore, the main lens barrel is also provided with a focusing mechanism that cooperates with the focusing lens mount.

[0010] Furthermore, the focusing mechanism includes a micro switch, a motor frame mounted above the main lens barrel, and a motor and potentiometer mounted on the motor frame. A cam is fitted around the outside of the main lens barrel, and the cam has a cam groove. A guide pin connected to the focusing lens mount is provided in the cam groove. A motor gear is provided at the output end of the motor, and a potentiometer gear is provided on the output shaft of the potentiometer. The motor gear and the potentiometer gear mesh with the cam through a pulley mounted on the motor frame.

[0011] Furthermore, the cam is provided with a focusing stop pin, and the focusing stop pin is provided with a silicone sleeve.

[0012] An imaging method for a long-wave infrared motorized focusing lens, wherein light passes sequentially through a positive lens A, a negative lens B, and a positive lens C to form an image.

[0013] An imaging method for a long-wave infrared motorized focusing lens, wherein the focusing lens group moves rapidly to the corresponding position according to the ambient temperature via a potentiometer-calibrated value to ensure clear imaging under different temperature conditions; when the focusing lens group moves to the upper or lower limit position, the focusing stop pin contacts the micro switch to cut off the power supply.

[0014] Compared with the prior art, the present invention has the following advantages: the lens achieves 100mm fixed-focus imaging, and the focus group can be moved to search for and track objects at different distances under different temperatures, making the lens applicable to forest fire prevention and border and coastal defense. Attached Figure Description

[0015] Figure 1 This is a diagram of the optical system in this invention;

[0016] Figure 2 This is a cross-sectional view of the lens in this invention;

[0017] Figure 3 This is a diagram of the electric focusing mechanism of the present invention;

[0018] Figure 4 This is an isometric side view of the lens of the present invention;

[0019] In the diagram: 1-Positive lens A; 2-Negative lens B; 3-Positive lens C; 4-Main lens barrel; 5-Connecting flange; 6-First annular step surface; 7-A-piece retaining ring; 8-Second annular step surface; 9-B-piece retaining ring; 10-Focusing lens mount; 11-Third annular step surface; 12-C-piece retaining ring; 13-Micro switch; 14-Motor bracket; 15-Motor; 16-Potentialistor; 17-Cam; 18-Cam groove; 19-Guide pin; 20-Motor gear; 21-Potentialistor gear; 22-Transfer wheel; 23-Focusing stop pin; 24-Silicone sleeve; 25-Switch bracket. Detailed Implementation

[0020] To make the above features and advantages of the present invention more readily understood, specific embodiments are described below in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0021] refer to Figures 1 to 4

[0022] A long-wave infrared motorized focusing lens includes a main lens barrel 4. Inside the main lens barrel, a front fixed lens group and a focusing lens group are arranged sequentially from left to right along the light incident direction. The front fixed lens group includes a positive lens A1 and a negative lens B2 arranged sequentially from left to right. The focusing lens group is provided with a positive lens C3. A connecting flange 5 is installed at the right end of the main lens barrel, and the entire lens is connected to the camera movement through the connecting flange.

[0023] In this embodiment, the air gap between the positive lens A and the negative lens B is 38.66 mm, and the air gap between the negative lens B and the positive lens C is 19.54 mm to 27.04 mm.

[0024] In this embodiment, the main lens barrel is provided with a first annular stepped surface 6 for abutting the right peripheral portion of the positive lens A, and an A-plate retaining ring 7 for abutting the left peripheral portion of the positive lens A is screwed into the main lens barrel, thereby fixing the positive lens A by the cooperation of the A-plate retaining ring and the first annular stepped surface 6. See also Figure 2 .

[0025] In this embodiment, the main lens barrel is provided with a second annular stepped surface 8 for abutting the right end periphery of the negative lens B, and a B-piece retaining ring 9 for abutting the left end periphery of the negative lens B is screwed into the main lens barrel, thereby fixing the positive lens B by the cooperation of the B-piece retaining ring and the second annular stepped surface. See also Figure 2 .

[0026] In this embodiment, a focusing lens mount 10 is provided inside the main lens barrel, and the positive lens C is installed inside the focusing lens mount. The focusing lens mount has a third annular stepped surface 11 for abutting the right peripheral side of the positive lens C. A C-plate retaining ring 12 for abutting the left peripheral side of the positive lens C is screwed into the focusing lens mount, thereby fixing the C-plate retaining ring 12 by cooperating with the third annular stepped surface. See also... Figure 2 .

[0027] In this embodiment, the main lens barrel is also equipped with a focusing mechanism that cooperates with the focusing lens mount. The focusing mechanism includes a microswitch 13 mounted on the main lens barrel via a switch bracket 25, a motor bracket 14 positioned above the main lens barrel, and a motor 15 and a potentiometer 16 mounted on the motor bracket. A cam 17 is fitted onto the outside of the main lens barrel. The cam and the main lens barrel are meshed to ensure a smooth and consistent operation. The cam is limited by a connecting flange. The cam has a cam groove 18, within which a guide pin 19 connected to the focusing lens mount is located. The output end of the motor is equipped with a motor gear 20, and the output shaft of the potentiometer is equipped with a potentiometer gear 21. The motor gear and the potentiometer gear mesh with the cam via a guide wheel 22 mounted on the motor bracket. See also... Figure 3 .

[0028] In this embodiment, the focusing lens group can be quickly moved to the corresponding position according to the value calibrated by the potentiometer based on the ambient temperature, ensuring clear imaging under different temperature conditions.

[0029] In this embodiment, the cam is equipped with a focusing stop 23. When the focusing assembly reaches its upper or lower limit position, the focusing stop contacts a micro switch to cut off the power supply, preventing the motor from stalling. The focusing stop is equipped with a silicone sleeve 24 to cushion the movement contact between the stop and the switch. (See also...) Figure 4 .

[0030] In this embodiment, the lens can achieve the following optical specifications:

[0031] (1) Operating wavelength: 8um~12um;

[0032] (2) Focal length: 100mm;

[0033] (2) Detector: Mid-wave infrared cooled detector 640x512 12um;

[0034] (3) Field of view: 4.38° (H) × 3.51° (V);

[0035] (4) Relative aperture: F1.2.

[0036] In this embodiment, the lens parameters of the front fixed lens group and the focusing lens group are shown in the table below:

[0037] Table 1.

[0038] As shown in Table 1, when the radius of curvature is positive, the center of the surface is on one side of the imaging plane; otherwise, the radius of curvature is negative. The equations for the aspherical surface types involved in the table are as follows:

[0039] .

[0040] The specific parameters of the aspherical portion shown in Table 1 are explained as follows:

[0041] Among them, S4: c=1 / R, R=28.098, k=0, A0=0, A1=4.0343357E-006, A2=1.4838816E -009, A3=6.4098247E-011, A4=-2.1999609E-013, A5=4.6913364E-016;

[0042] Where S6: c=1 / R, R=392.938, k=0, A0=0, A1=-3.0816753E-006, A2=3.1332009E-009, A3=-3.7614253E-011, A4=1.7295434E-013, A5=-3.264859E-016.

[0043] An imaging method for a long-wave infrared motorized focusing lens, wherein light passes sequentially through a positive lens A, a negative lens B, and a positive lens C to form an image.

[0044] The above description is only a preferred embodiment of the present invention. For those skilled in the art, designing different forms of long-wave infrared motorized focusing lenses and their imaging methods according to the teachings of the present invention does not require creative labor. All equivalent changes, modifications, substitutions and variations made in accordance with the scope of the patent application of the present invention without departing from the principles and spirit of the present invention shall be covered by the present invention.

Claims

1. A long-wave infrared motorized focusing lens, comprising a main lens barrel, characterized in that, The main lens barrel consists of a front fixed lens group and a focusing lens group arranged sequentially from left to right along the incident light direction. The front fixed lens group consists of a positive lens A and a negative lens B arranged sequentially from left to right. The focusing lens group consists of a positive lens C and is movable. A connecting flange is installed on the right side of the main lens barrel. The air gap between the positive lens A and the negative lens B is 38.66 mm, and the air gap between the negative lens B and the positive lens C is 19.54 mm to 27.04 mm.

2. The long-wave infrared motorized focusing lens according to claim 1, characterized in that, The main lens barrel is provided with a first annular stepped surface for abutting the right end periphery of the positive lens A, and an A-plate pressure ring for fixing the positive lens A is screwed into the main lens barrel.

3. A long-wave infrared motorized focusing lens according to claim 2, characterized in that, The main lens barrel is provided with a second annular stepped surface for abutting the right end periphery of the negative lens B, and a B-piece retaining ring for fixing the negative lens B is screwed into the main lens barrel.

4. A long-wave infrared motorized focusing lens according to claim 1 or 3, characterized in that, A focusing lens mount is provided inside the main lens barrel, and the positive lens C is installed inside the focusing lens mount. The focusing lens mount is provided with a third annular stepped surface for abutting the right end periphery of the positive lens C. A C-plate retaining ring for fixing the positive lens C is screwed into the focusing lens mount.

5. A long-wave infrared motorized focusing lens according to claim 4, characterized in that, The main lens barrel is also equipped with a focusing mechanism that cooperates with the focusing lens mount.

6. A long-wave infrared motorized focusing lens according to claim 5, characterized in that, The focusing mechanism includes a micro switch, a motor frame mounted above the main lens barrel, and a motor and potentiometer mounted on the motor frame. A cam is fitted around the outside of the main lens barrel. The cam has a cam groove, and a guide pin connected to the focusing lens mount is provided in the cam groove. The output end of the motor is provided with a motor gear, and the output shaft of the potentiometer is provided with a potentiometer gear. The motor gear and the potentiometer gear mesh with the cam through a pulley mounted on the motor frame.

7. A long-wave infrared motorized focusing lens according to claim 6, characterized in that, The cam is provided with a focusing stop pin, and the focusing stop pin is provided with a silicone sleeve.

8. An imaging method for a long-wave infrared motorized focusing lens as described in any one of claims 1-7, characterized in that, Light rays pass through positive lens A, negative lens B, and positive lens C in sequence to form an image.

9. An imaging method for a long-wave infrared electrically adjustable focusing lens as described in claim 7, characterized in that, The focusing lens assembly moves quickly to the corresponding position according to the value calibrated by the potentiometer based on the ambient temperature, ensuring clear imaging under different temperature conditions; when the focusing lens assembly moves to the upper or lower limit position, the focusing stop pin contacts the micro switch to cut off the power.

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