Objective centering structure and assembling method of continuous zooming infrared thermal imager

Abstract

The application belongs to the field of infrared imaging assembly technology and relates to an objective lens centering structure and an assembling method of a continuous zoom infrared thermal imager, which comprises a first objective lens, a second objective lens, a first objective lens centering lens barrel, a second objective lens centering lens barrel, a first objective lens pressing ring, a second centering lens barrel pressing ring, a second centering lens barrel adjusting gasket, an objective lens component pressing ring, an objective lens component adjusting gasket and a lens support, etc. Through the structure and the assembling method, coaxiality and angular deviation requirements between the first objective lens and the second objective lens can be realized, the machining difficulty of parts can be reduced, and adjustment during subsequent assembly is facilitated. The first objective lens can be effectively pressed by the first objective lens pressing ring, and the image stability of the optical system under vibration conditions is enhanced. The first objective lens centering lens barrel has screw holes perpendicular to the front end face, facilitating assembly and disassembly of the objective lens component. The first objective lens centering lens barrel has uniformly distributed screw holes in the radial direction, and the coaxiality of the second objective lens can be adjusted after assembly is completed.

Description

Technical Field

[0001] This invention belongs to the field of infrared imaging assembly technology, and relates to an objective lens centering structure and assembly method for a continuous zoom infrared thermal imager. Background Technology

[0002] Infrared imaging systems enable target observation, tracking, and aiming. Infrared imaging technology has developed rapidly in recent years, with increasingly wider applications, leading to ever-increasing demands on infrared zoom optical systems. Current research on airborne continuous zoom infrared imaging systems focuses on large zoom ratios, miniaturization, and lightweight design. Current coaxial continuous zoom optical systems typically consist of two objective lenses: a first objective and a second objective. To achieve high imaging quality, the optical system requires high coaxiality between the two objective lenses. Furthermore, the objective lens assembly itself is highly sensitive to optical axis changes, significantly impacting image quality and stability under complex airborne environments such as vibration. Therefore, a stable and reliable mechanical structure is needed to ensure both the coaxiality of the two objective lenses and structural stability. Most existing objective lens assembly technologies achieve coaxiality between the first and second objective lenses through reference conversion, resulting in multiple parts requiring coaxiality conversion and clearance fits, affecting the coaxial accuracy between the two objective lenses. Summary of the Invention

[0003] The technical problem to be solved by this invention:

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a lens centering structure and assembly method for a continuous zoom infrared thermal imager, which ensures high coaxiality of the two objectives after assembly, and reduces the processing difficulty of the centering lens barrel parts and improves assembly efficiency.

[0005] One technical solution provided by this invention is:

[0006] A lens centering structure for a continuous zoom infrared thermal imager includes a first lens centering tube, a second lens centering tube, a first lens retaining ring, a second lens centering tube retaining ring, and a second lens centering tube adjustment shim. The second lens centering tube is concentrically fixed inside the first lens centering tube, and the second objective lens is centered inside the second lens centering tube. Using the optical axis of the second objective lens as a reference, a transmission-type infrared centering device is used to center and install the first objective lens inside the first lens centering tube. The first lens retaining ring is fixedly installed on the outer edge of the non-working optical surface of the first objective lens, and the second lens centering tube retaining ring is fixedly installed on the end face of the second lens centering tube. A second lens centering tube adjustment shim is provided between the first and second objectives.

[0007] A further technical solution of the present invention is: the second objective lens centering tube is installed inside the first objective lens centering tube by centering turning, and the first objective lens centering tube and the second objective lens centering tube are respectively provided with grooves of the same width and the same angle position for alignment and positioning of the first objective lens centering tube and the second objective lens centering tube.

[0008] A further technical solution of the present invention is: the front end face of the first objective lens centering tube is evenly distributed with threaded holes perpendicular to the end face for disassembling and assembling the objective lens; its outer cylindrical surface is provided with a plurality of radially distributed radial threaded holes along the circumference for adjusting the radial position of the second objective lens centering tube, and the coaxiality of the optical axis of the second objective lens and the first objective lens is adjusted by screwing different sizes.

[0009] A further technical solution of the present invention is: both the inner walls of the first objective lens centering tube and the second objective lens centering tube are provided with glue storage grooves, and both are provided with evenly distributed glue injection holes in the radial direction, so that the first objective lens and the first objective lens centering tube, and the second objective lens and the second objective lens centering tube are flexibly bonded by silicone rubber.

[0010] A further technical solution of the present invention is: the second objective lens centering tube is provided with an annular groove to avoid installation interference of the second objective lens.

[0011] A further technical solution of the present invention is: the first objective lens centering tube is installed in the lens support, such that the outer cylindrical surface A and end surface B of the first objective lens centering tube are engaged with the inner cylindrical surface and end surface in the lens support; the objective lens component pressure ring is fixedly installed on the end surface of the first objective lens centering tube, thereby fixing the first objective lens centering tube to the lens support.

[0012] A further technical solution of the present invention is: the first objective lens and the second objective lens form an objective lens group, and an objective lens component adjustment shim is provided between the objective lens group and the external lens of the objective lens group.

[0013] A further technical solution of the present invention is: the first objective lens retaining ring, the second centering tube retaining ring, and the objective lens component retaining ring are respectively screwed and pressed to tighten the first objective lens, the second objective lens centering tube, and the first objective lens centering tube.

[0014] Another technical solution provided by this invention is:

[0015] A method for assembling and adjusting the objective lens centering structure of a continuous zoom infrared thermal imager, comprising the following steps:

[0016] Step 1: Using the optical axis of the second objective lens as a reference, machine the centering tube of the second objective lens, and then flexibly bond the second objective lens and the centering tube of the second objective lens together with silicone rubber.

[0017] Step 2: Insert the centering barrel of the second objective lens after centering and machining into the centering barrel of the first objective lens. Tighten the pressure ring of the second centering barrel to press it firmly on the end face of the second objective lens centering barrel to reliably fix the second objective lens centering barrel and ensure that the engraved grooves in the second objective lens centering barrel and the first objective lens centering barrel are aligned.

[0018] Step 3: Using a transmission infrared centering device, with the optical axis of the second objective lens as the reference, center and install the first objective lens inside the centering tube of the first objective lens. Tighten the first objective lens retaining ring to press it firmly onto the non-working optical surface of the first objective lens to reliably fix the first objective lens.

[0019] Step 4: Use the second centering barrel adjustment shim to adjust the optical spacing between the first objective lens and the second objective lens. Install the assembled objective lens assembly into the lens mount. Use the objective lens assembly adjustment shim to adjust the optical spacing between the objective lens group and the external lens of the objective lens group. Tighten the objective lens assembly retaining ring to press it firmly onto the end face of the first objective lens centering barrel to complete the assembly and adjustment.

[0020] Beneficial effects

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. This invention provides a lens centering structure for an airborne observation and aiming continuous zoom infrared thermal imager. After the second lens centering tube is concentrically fixed inside the first lens centering tube, a transmission infrared centering device is used. This allows the first lens to be assembled directly with the optical axis of the second lens as the reference, reducing the intermediate reference required during assembly and reducing the steps that may cause assembly errors. The coaxiality between the first and second lenses can reach within Φ0.015, achieving a high coaxiality effect.

[0023] 2. This invention provides a lens centering structure for an airborne observation and aiming continuous zoom infrared thermal imager. After the outer cylindrical surface A and end surface B of the first objective lens centering tube are high-precision mating surfaces with the inner cylindrical surface and end surface in the lens support, the inner and outer cylindrical surfaces of the first objective lens centering tube do not need to have very high coaxial accuracy, which reduces the processing difficulty. After the second objective lens centering tube is installed on the first objective lens centering tube by centering turning, the high-precision assembly of the first objective lens can be completed without removal.

[0024] 3. After assembly, the optical axis position of the second objective lens can be adjusted through the threaded hole to meet the needs of optical axis adjustment during subsequent debugging. Attached Figure Description

[0025] Figure 1 : A cross-sectional view of the centering structure of the objective lens of the airborne observation and aiming device for the present invention;

[0026] Figure 2: A three-dimensional schematic diagram of the front of the objective lens centering structure of the present invention (the first objective lens retaining ring 5 is not shown);

[0027] Figure 3 : A three-dimensional schematic diagram of the back side of the objective lens centering structure of this invention.

[0028] Figure 4 : Rear view of the objective lens centering structure of the present invention (second centering lens barrel pressure ring 6 not shown);

[0029] Figure 5 : A cross-sectional view of the optimal embodiment of the present invention;

[0030] Figure 6 Side view of the preferred embodiment of the present invention (first objective lens retaining ring 5 not shown).

[0031] In the diagram: 1. First objective lens, 2. Second objective lens, 3. First objective lens centering tube, 4. Second objective lens centering tube, 5. First objective lens retaining ring, 6. Second centering tube retaining ring, 7. Second centering tube adjusting shim, 8. Objective lens component retaining ring, 9. Objective lens component adjusting shim, 10. Lens support. Detailed Implementation

[0032] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0034] As attached Figure 1-6As shown, this invention provides an objective lens centering structure for a continuous zoom infrared thermal imager used in airborne observation and aiming devices. It includes a first objective lens centering tube 3, a second objective lens centering tube 4, a first objective lens retaining ring 5, a second centering tube retaining ring 6, and a second centering tube adjusting shim 7. The second objective lens centering tube 4 is concentrically fixed inside the first objective lens centering tube 3. The second objective lens 2 is centered and installed inside the second objective lens centering tube 4. Using the optical axis of the second objective lens 2 as a reference, a transmission-type infrared centering device is used to center and install the first objective lens 1 inside the first objective lens centering tube 3. The first objective lens retaining ring 5 is fixed to the non-working optical surface of the first objective lens 1, the second centering tube retaining ring 6 is fixed to the end face of the second objective lens centering tube 4, and the second centering tube adjusting shim 7 is provided between the first objective lens 1 and the second objective lens 2.

[0035] The inner wall of the first objective lens centering tube 3 has a glue reservoir and radially distributed glue injection holes. The first objective lens 1 and the first objective lens centering tube 3 are flexibly bonded together with silicone rubber. The front end face of the first objective lens centering tube 3 has threaded holes perpendicular to the end face. After screwing in the screws, they can be used as handles to disassemble and assemble the objective lens components. The outer cylindrical surface of the first objective lens centering tube 3 has multiple radially distributed threaded holes along the circumference. After assembly, screws can be screwed in to adjust the radial position of the second objective lens centering tube 4, and further adjust the coaxiality of the optical axis of the second objective lens 2 and the first objective lens 1. The first objective lens retaining ring 5 is pressed tightly onto the non-working optical surface of the first objective lens 1 by screwing in the threads.

[0036] The second objective lens centering tube 4 has a glue reservoir and radially distributed glue injection holes. The second objective lens 2 and the second objective lens centering tube 4 are flexibly bonded together with silicone rubber. The second objective lens centering tube 4 has an annular groove to prevent direct contact between the second objective lens 2 and the edge at the junction of the outer cylindrical surface and the working optical surface when the second objective lens 2 is installed in place. This can reduce the possible damage and cracking of the optical lens edge under vibration conditions. The second centering tube pressure ring 6 is tightened into the end face of the second objective lens centering tube 4 by screwing it in, so as to reliably fix the second objective lens centering tube 4.

[0037] The optical distance between the first objective lens 1 and the second objective lens 2 is adjusted by the second centering tube adjusting shim 7; using a transmission infrared centering instrument, with the optical axis of the second objective lens 2 as the reference, the first objective lens 1 is centered and installed in the first objective lens centering tube 3; the first objective lens centering tube 3 and the second objective lens centering tube 4 are respectively provided with engraved grooves of the same width, consistent angle position and aligned, which can ensure the repeatability accuracy of the optical axis after repeated disassembly and assembly of the second objective lens centering tube 4.

[0038] The outer cylindrical surface A and end face B of the first objective lens centering tube 3 are high-precision mating surfaces with the inner cylindrical surface and end face of the lens support 10; the objective lens component pressure ring 8 is pressed tightly to the end face of the first objective lens centering tube 3 by screwing it in, thus fixing the first objective lens centering tube 3 to the lens support 10. The first objective lens 1 and the second objective lens 2 form an objective lens group. The optical spacing between the objective lens group and the external lenses of the objective lens group can be adjusted by the objective lens component adjustment shim 9.

[0039] A method for assembling and adjusting the objective lens centering structure of a continuous zoom infrared thermal imager, comprising the following steps:

[0040] Step 1: Using the optical axis of the second objective lens 2 as a reference, machine the centering tube 4 of the second objective lens, and flexibly bond the second objective lens 2 and the centering tube 4 of the second objective lens with silicone rubber.

[0041] Step 2: Insert the centering barrel 4 of the second objective lens after centering and machining into the centering barrel 3 of the first objective lens. The pressure ring 6 of the second centering barrel is pressed tightly on the end face of the second objective lens centering barrel 4 by screwing it in, so that the second objective lens centering barrel 4 is reliably fixed and the engraved grooves in the second objective lens centering barrel 4 and the first objective lens centering barrel 3 are aligned.

[0042] Step 3: Using a transmission infrared centering instrument, with the optical axis of the second objective lens 2 as the reference, the first objective lens 1 is centered and installed in the first objective lens centering tube 3. The first objective lens retaining ring 5 is pressed tightly onto the non-working optical surface of the first objective lens 1 by screwing it in, so as to reliably fix the first objective lens 1.

[0043] Step 4: Use the second centering lens barrel adjustment shim 7 to adjust the optical distance between the first objective lens 1 and the second objective lens 2. Install the installed objective lens components into the lens support 10. Use the objective lens component adjustment shim 9 to adjust the optical distance between the objective lens group and the external lens of the objective lens group. The objective lens component retaining ring 8 is pressed tightly onto the end face of the first objective lens centering lens barrel 3 by screwing it in.

[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for assembling and adjusting the objective lens centering structure of a continuous zoom infrared thermal imager, characterized in that: The objective lens centering structure of the continuous zoom infrared thermal imager includes a first objective lens centering tube, a second objective lens centering tube, a first objective lens retaining ring, a second centering tube retaining ring, and a second centering tube adjusting shim. The second objective lens centering tube is concentrically fixed inside the first objective lens centering tube, and the second objective lens is centered inside the second objective lens centering tube. Using the optical axis of the second objective lens as a reference, a transmission-type infrared centering device is used to center and install the first objective lens inside the first objective lens centering tube. The first objective lens retaining ring is fixedly installed on the outer edge of the non-working optical surface of the first objective lens, and the second centering tube retaining ring is fixedly installed on the end face of the second objective lens centering tube. A second centering tube adjusting shim is provided between the first objective lens and the second objective lens. Assembly and adjustment steps: Step 1: Using the optical axis of the second objective lens as a reference, machine the centering tube of the second objective lens, and then flexibly bond the second objective lens and the centering tube of the second objective lens together with silicone rubber. Step 2: Insert the centering barrel of the second objective lens after centering and machining into the centering barrel of the first objective lens. Tighten the pressure ring of the second centering barrel to press it firmly on the end face of the second objective lens centering barrel to reliably fix the second objective lens centering barrel and ensure that the engraved grooves in the second objective lens centering barrel and the first objective lens centering barrel are aligned. Step 3: Using a transmission infrared centering device, with the optical axis of the second objective lens as the reference, center and install the first objective lens inside the centering tube of the first objective lens. Tighten the first objective lens retaining ring to press it firmly onto the non-working optical surface of the first objective lens to reliably fix the first objective lens. Step 4: Use the second centering barrel adjustment shim to adjust the optical spacing between the first objective lens and the second objective lens. Install the assembled objective lens assembly into the lens mount. Use the objective lens assembly adjustment shim to adjust the optical spacing between the objective lens group and the external lens of the objective lens group. Tighten the objective lens assembly retaining ring to press it firmly onto the end face of the first objective lens centering barrel to complete the assembly and adjustment.

2. The assembly and adjustment method according to claim 1, characterized in that: The second objective lens centering tube is installed inside the first objective lens centering tube by centering turning. The first and second objective lens centering tubes are respectively provided with engraved grooves of the same width and angle position for alignment and positioning of the first and second objective lens centering tubes.

3. The assembly and adjustment method according to claim 1, characterized in that: The front end face of the first objective lens centering tube is evenly distributed with threaded holes perpendicular to the end face for disassembling and assembling the objective lens; its outer cylindrical surface is provided with multiple radially distributed radial threaded holes along the circumference for adjusting the radial position of the second objective lens centering tube, and the coaxiality of the optical axis of the second objective lens and the first objective lens can be further adjusted by screwing different sizes.

4. The assembly and adjustment method according to claim 1, characterized in that: Both the first objective lens centering tube and the second objective lens centering tube have glue storage grooves on their inner walls and glue injection holes evenly distributed in the radial direction, so that the first objective lens and the first objective lens centering tube, and the second objective lens and the second objective lens centering tube are flexibly bonded by silicone rubber.

5. The assembly and adjustment method according to claim 1, characterized in that: The second objective lens has an annular groove inside the centering tube to prevent installation interference.

6. The assembly and adjustment method according to claim 1, characterized in that: The first objective lens centering tube is installed in the lens support, such that the outer cylindrical surface A and end face B of the first objective lens centering tube mate with the inner cylindrical surface and end face in the lens support; the objective lens component retaining ring is fixedly installed on the end face of the first objective lens centering tube, thus fixing the first objective lens centering tube to the lens support.

7. The assembly and adjustment method according to claim 6, characterized in that: The first objective lens and the second objective lens form an objective lens group, and an objective lens component adjustment shim is provided between the objective lens group and the external lens of the objective lens group.

8. The assembly and adjustment method according to claim 6, characterized in that: The first objective lens retaining ring, the second centering tube retaining ring, and the objective lens component retaining ring are screwed and tightened to secure the first objective lens, the second objective lens centering tube, and the first objective lens centering tube, respectively.

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