Unpowered mechanically-driven high-stability lens

Abstract

The invention discloses an unpowered mechanically-driven high-stability lens, and relates to the technical field of optical lenses, the unpowered mechanically-driven high-stability lens comprises a first lens barrel and a plurality of elastic arm groups, and the first lens barrel is provided with a plurality of lenses along the axial direction; a plurality of elastic arm groups are arranged on the inner wall of the first lens cone, each lens is in contact with one elastic arm group, the plurality of elastic arm groups are distributed along the axial direction of the first lens cone, each elastic arm group comprises a plurality of elastic arms, and in one elastic arm group, the plurality of elastic arms are distributed around the circumferential direction of the first lens cone; wherein the elastic arm is configured in a way that the thermal expansion direction of the elastic arm is opposite to the thermal movement direction of the lens contacted with the elastic arm. The high-stability lens without power mechanical drive can still perform stable imaging under the condition of large temperature change.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and particularly relates to a high-stability lens driven by a non-powered mechanical drive. Background Art

[0002] In extreme usage scenarios such as aerospace, deep-sea exploration, and industrial precision inspection, the environmental temperature changes greatly, and the thermal stability of ordinary optical lenses is insufficient. In an environment with large temperature changes, for example, within a temperature fluctuation range of -20°C to 60°C, the displacement of the lens group of the optical lens can reach ±0.1 mm, and the displacement of the lens group will cause the imaging quality of the optical lens to deteriorate. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a high-stability lens driven by a non-powered mechanical drive, which can still stably image under large temperature changes.

[0004] The high-stability lens driven by a non-powered mechanical drive according to an embodiment of the present invention includes a first lens barrel, and a plurality of lenses are arranged along the axis of the first lens barrel; A plurality of elastic arm groups, wherein a plurality of the elastic arm groups are provided on the inner wall of the first lens barrel, each lens is in contact with one of the elastic arm groups, the plurality of elastic arm groups are distributed along the axis of the first lens barrel, and each elastic arm group includes a plurality of elastic arms. In one elastic arm group, the plurality of elastic arms are distributed circumferentially around the first lens barrel; Wherein, the elastic arm is configured such that the direction of thermal expansion of the elastic arm is opposite to the direction of thermal movement of the lens with which the elastic arm is in contact.

[0005] The high-stability lens driven by a non-powered mechanical drive according to an embodiment of the present invention has at least the following beneficial effects: Each lens is connected to an elastic arm group, and the elastic arm is configured such that the direction of thermal expansion of the elastic arm is opposite to the direction of thermal movement of the lens. When the lens moves thermally, the reverse expansion deformation of the elastic arm can resist the displacement of the lens, and the displacement amount of the lens due to heat is minimized as much as possible, ensuring the imaging quality of the optical lens under large temperature changes.

[0006] According to some embodiments of the present invention, the elastic arm includes a mounting portion and a contact portion. The mounting portion is inserted into the first lens barrel. Along the axis of the first lens barrel, the contact portion is provided at one end of the mounting portion, and the contact portion extends towards the center in the radial direction of the first lens barrel, and the lens is in contact with the contact portion.

[0007] According to some embodiments of the present invention, a flexible sheet is provided between the contact portion and the lens. The flexible sheet is fixed to the contact portion, and the lens is in contact with the flexible sheet.

[0008] According to some embodiments of the present invention, the contact stress between the elastic arm and the lens is < 0.2 Mpa.

[0009] According to some embodiments of the present invention, each of the elastic arm groups includes at least three elastic arms, and the plurality of elastic arms are evenly distributed circumferentially around the first lens barrel.

[0010] According to some embodiments of the present invention, a plurality of damping column groups are provided on the inner wall of the first lens barrel, each lens is in contact with one damping column group, the plurality of damping column groups are axially distributed along the first lens barrel, each damping column group includes a plurality of damping columns, in one damping column group, the plurality of damping columns are circumferentially distributed around the first lens barrel, the axial direction of the damping column is parallel to the axial direction of the first lens barrel, and the side wall of the damping column is in contact with the side wall of the lens.

[0011] According to some embodiments of the present invention, the damping column is a rubber column, and a metal sheet is embedded in the rubber column.

[0012] According to some embodiments of the present invention, each of the damping column groups includes at least six damping columns, and the plurality of damping columns are evenly distributed circumferentially around the first lens barrel.

[0013] According to some embodiments of the present invention, a second lens barrel is sleeved outside the first lens barrel, the first lens barrel and the second lens barrel are coaxially arranged, a plurality of through threaded holes are provided on the side wall of the second lens barrel, the plurality of threaded holes are evenly distributed circumferentially around the second lens barrel, a fine adjustment screw is provided at each threaded hole, and the end of the fine adjustment screw abuts against the outer side wall of the first lens barrel.

[0014] According to some embodiments of the present invention, a liquid metal is coated between the contact surfaces of the elastic arm and the lens, the liquid metal is in a solid state within the range of the first temperature threshold, and the liquid metal is in a liquid state within the range of the second temperature threshold, wherein the lens operates within the range of the first temperature threshold.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the drawings and embodiments, wherein: Figure 1 is an exploded view of a high-stability lens with a non-powered mechanical drive according to the first embodiment of the present invention; Figure 2The first - perspective cross - sectional view of the high - stability lens driven by a non - powered mechanical drive according to the first embodiment of the present invention; Figure 3 The second - perspective cross - sectional view of the high - stability lens driven by a non - powered mechanical drive according to the first embodiment of the present invention; Figure 4 The partial enlarged cross - sectional view of the high - stability lens driven by a non - powered mechanical drive according to the first embodiment of the present invention.

[0017] Reference numerals: The first lens barrel 100, the lens 200, the elastic arm group 300, the mounting part 311, the contact part 312, the damping column group 400, the second lens barrel 500, the fine - tuning screw 600. Detailed implementation manners

[0018] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0019] In the description of the present invention, it should be understood that the orientation descriptions such as up and down refer to the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0020] In the description of the present invention, "a plurality" means more than two. If there is a description of the first and the second, it is only for the purpose of distinguishing technical features and should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0021] In the description of the present invention, unless otherwise clearly defined, words such as "set", "installed", "connected" should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0022] As described in the background art, for a common optical lens mainly composed of an aluminum alloy lens barrel, within a temperature difference of - 20°C to 60°C, the displacement of the lens group is as high as ±0.1 mm, which will cause defocus aberration and greatly reduce the imaging quality.

[0023] Refer to Figure 1 and Figure 2 As shown, a high - stability lens driven by a non - powered mechanical drive according to an embodiment of the present invention includes a first lens barrel 100 and a plurality of elastic arm groups 300.

[0024] The first lens barrel 100 is provided with a plurality of lenses 200 along the axial direction; a plurality of elastic arm groups 300 are provided on the inner wall of the first lens barrel 100, each lens 200 is in contact with an elastic arm group 300, and the plurality of elastic arm groups 300 are distributed along the axial direction of the first lens barrel 100. Each elastic arm group 300 includes a plurality of elastic arms, and in one elastic arm group 300, the plurality of elastic arms are distributed around the circumferential direction of the first lens barrel 100; wherein, the elastic arms are configured such that the direction of thermal expansion of the elastic arms is opposite to the direction of thermal movement of the lenses in contact therewith.

[0025] Each lens 200 is connected to an elastic arm group 300, and an elastic arm group 300 includes a plurality of elastic arms, that is, each lens 200 is in contact connection with a plurality of elastic arms. The elastic arms are configured such that the direction of thermal expansion of the elastic arms is opposite to the direction of thermal movement of the lens 200. When the lens 200 moves thermally, the deformation of the elastic arms due to expansion is opposite to the displacement of the lens 200, which can resist the displacement of the lens 200 and minimize the displacement amount of the lens 200 due to heat as much as possible, ensuring the imaging quality of the optical lens under large temperature changes. In some embodiments, in the range of -40°C to 85°C, through the axial displacement compensation of the elastic arms for the lens 200, the displacement amount can be controlled within <±0.05 mm.

[0026] Preferably, the first lens barrel 100 can be made of a material with a low coefficient of thermal expansion, such as invar steel, whose coefficient of thermal expansion is 1.2×10 -6 / °C.

[0027] Furthermore, in a specific embodiment, the thickness of the elastic arm is 0.2 mm. To fit the first lens barrel 100, the elastic arm is arc-shaped with a radius of 8 mm. It should be understood that the radius of the elastic arm is adjusted according to the radius or diameter size of the optical lens. In this embodiment, the radius of the elastic arm is selected as 8 mm, which is not limited to the optimal value.

[0028] It can be understood that the elastic arm includes a mounting portion 311 and a contact portion 312. The mounting portion 311 is inserted into the first lens barrel 100. Along the axial direction of the first lens barrel 100, the contact portion 312 is provided at one end of the mounting portion 311, and the contact portion 312 extends radially towards the center of the first lens barrel 100, and the lens 200 is in contact with the contact portion 312.

[0029] The mounting portion 311 is used for the installation and fixation between the elastic arm and the first lens barrel 100, and the contact portion 312 is used for the contact between the elastic arm and the lens 200. When the elastic arm expands thermally, the mounting portion 311 generates the main deformation, which is transmitted to the lens 200 through the contact portion 312 to compensate for the displacement of the lens 200.

[0030] It is understandable that a flexible sheet is provided between the contact portion 312 and the lens 200. The flexible sheet is fixed to the contact portion 312, and the lens 200 is in contact with the flexible sheet.

[0031] Preferably, the flexible sheet can be made of polyimide material, and the contact stress between the elastic arm and the lens 200 is controlled to be < 0.2 Mpa.

[0032] In the above embodiment, the thickness of the polyimide flexible sheet can be 0.3 mm, that is, the portion where the elastic arm contacts the lens 200 is a thin-wall structure with a thickness of 0.5 mm. Further, the elastic modulus of this thin-wall structure is 180 GPa. When the optical lens is heated, by utilizing the thermal expansion deformation of the elastic arm, within the range of -40°C to 85°C, the axial displacement of the lens 200 can be compensated through the deformation of the elastic arm, and the displacement of the lens 200 can be controlled to be < ±0.05 mm.

[0033] It should be understood that in a common optical lens, the lens and the lens barrel are rigidly connected, resulting in stress concentration at the edge of the lens, and the surface shape error > λ / 10 (λ = 632.8 nm), which affects the imaging accuracy of the optical lens. Controlling the contact stress between the elastic arm and the lens 200 to be < 0.2 Mpa, which is approximately stress-free support, can eliminate more than 95% of the assembly stress, and can control the surface shape error of the lens 200 to be < λ / 25, reaching the diffraction limit.

[0034] It is understandable that each elastic arm group 300 includes at least three elastic arms, and the multiple elastic arms are evenly distributed circumferentially around the first lens barrel 100, forming a stable contact structure with high coaxiality.

[0035] Refer to Figure 4 As shown, further, it is understandable that a liquid metal is coated on the contact surface between the elastic arm and the lens 200. The liquid metal is in a solid state within the range of the first temperature threshold and in a liquid state within the range of the second temperature threshold. Among them, the lens 200 operates within the range of the first temperature threshold. In Figure 4 the position indicated by the arrow is the filling area of the liquid metal.

[0036] During the filling process of the liquid metal, it is in a liquid state after being heated. The liquid metal is filled between the elastic arm and the lens 200, and it is necessary to wait for the liquid metal to turn into a solid state after cooling. It should be understood that the range of the second temperature threshold is larger than the range of the first temperature threshold, and the lens 200 of the lens operates within the range of the first temperature threshold, that is, in the working environment of the lens, even if the temperature rises, it will not cause the liquid metal to turn into a liquid state again. Using the liquid metal to connect the lens 200 can minimize the structural stress generated by the liquid metal connection layer on the lens 200.

[0037] It should be understood that in some embodiments, the liquid metal is specifically a gallium-indium-zinc alloy, which can remain solid at 150 °C and form a metal connection layer with a thickness of 1 μm to 2 μm after solidification. 5% by mass of silver nanoparticles can also be added to the liquid metal, which can increase the thermal conductivity to 30 W / (m·K), control the thermal response time within <10 s at a high temperature of 80 °C, effectively dissipate the thermal load of the lens 200, with a temperature gradient of <2 °C / mm, ensuring stable imaging quality. The combined application of the liquid metal and the elastic arm can achieve a displacement of the lens 200 of <±0.1 mm within a wide temperature range of -196 °C to 120 °C, reducing the thermal drift error by 90%.

[0038] It should be understood that ordinary optical lenses will resonate under mechanical vibration. For example, an ordinary optical lens with an aluminum alloy lens barrel will have a resonance amplitude of the lens >15 μm and an MTF value drop of >40% when vibrating above 50 Hz.

[0039] Refer to Figure 3 As shown, it can be understood that a plurality of damping column groups 400 are provided on the inner wall of the first lens barrel 100, each lens 200 is in contact with a damping column group 400, the plurality of damping column groups 400 are distributed along the axial direction of the first lens barrel 100, each damping column group 400 includes a plurality of damping columns, in a damping column group 400, the plurality of damping columns are distributed circumferentially around the first lens barrel 100, the axial direction of the damping column is parallel to the axial direction of the first lens barrel 100, and the side wall of the damping column is in contact with the side wall of the lens 200. Preferably, it can be understood that the damping column is a rubber column, and a metal sheet is embedded in the rubber column.

[0040] The damping column provides a damping effect for the lens 200. The purpose of embedding a metal sheet in the rubber column is to make the rubber column retain a certain rigidity and have a better damping effect. For example, in some embodiments, the diameter of the rubber damping column is 1.5 mm, and a beryllium bronze sheet with a thickness of 0.1 mm is embedded inside to form a rubber-metal composite damping structure with a Shore hardness of 60A. At a vibration frequency of 50 Hz to 1000 Hz, the vibration attenuation rate of the lens 200 is >95%.

[0041] It can be understood that each damping column group 400 includes at least six damping columns, and the plurality of damping columns are evenly distributed circumferentially around the first lens barrel 100.

[0042] In the above distribution structure of the damping columns, the optical lens achieves attenuation in the full frequency band of 50 Hz to 2000 Hz. Under a vibration of 10G (10 times the acceleration of gravity), the amplitude of the lens 200 is controlled within <3 μm, and the MTF value remains >30 lp / mm.

[0043] Furthermore, the number of damping columns in each damping column group 400 can be increased to eight, and tungsten alloy sheets with a thickness of 0.2 mm are embedded in the rubber damping columns, which can control the amplitude of the lens 200 < 2 μm under a 15G vibration, meeting the ultra-high dynamic resolution requirements of aerial photography.

[0044] Referring to Figure 3 As shown, it can be understood that a second lens barrel 500 is sleeved outside the first lens barrel 100. The first lens barrel 100 and the second lens barrel 500 are coaxially arranged. A plurality of through threaded holes are formed in the side wall of the second lens barrel 500. The plurality of threaded holes are evenly distributed around the circumference of the second lens barrel 500. Each threaded hole is provided with an adjusting screw 600. The end of the adjusting screw 600 abuts against the outer side wall of the first lens barrel 100.

[0045] By rotating the adjusting screw 600, the end of the adjusting screw 600 can abut against the first lens barrel 100 to change the coaxiality between the first lens barrel 100 and the second lens barrel 500. Using the adjusting screw 600 can minimize the assembly error between the first lens barrel 100 and the second lens barrel 500 as much as possible. For example, during the assembly process, a laser interferometer is used for real-time monitoring, and then the adjusting screw 600 is adjusted. In some embodiments, the pitch of the adjusting screw 600 is designed to be 0.02 mm, and the accuracy of the laser interferometer is ±0.005 μm, which can achieve the coaxiality between the first lens barrel 100 and the second lens barrel 500 < ±0.3 μm.

[0046] The embodiments of the present invention have been described in detail above with reference to the drawings. However, the present invention is not limited to the above embodiments. Various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. A high-stability lens driven by a non-powered mechanism, characterized in that Comprising: A first lens barrel (100), along the axis of which a plurality of lenses (200) are provided; A plurality of elastic arm groups (300), provided on the inner wall of the first lens barrel (100), each lens (200) is in contact with one elastic arm group (300), the plurality of elastic arm groups (300) are distributed along the axis of the first lens barrel (100), each elastic arm group (300) includes a plurality of elastic arms, and in one elastic arm group (300), the plurality of elastic arms are distributed circumferentially around the first lens barrel (100); Wherein, the elastic arm is configured such that the direction of thermal expansion of the elastic arm is opposite to the direction of thermal movement of the lens in contact with the elastic arm.

2. The power-free mechanically-driven highly stable lens according to claim 1, wherein The elastic arm includes a mounting portion (311) and a contact portion (312), the mounting portion (311) is inserted into the first lens barrel (100), along the axis of the first lens barrel (100), the contact portion (312) is provided at one end of the mounting portion (311), and the contact portion (312) extends towards the center in the radial direction of the first lens barrel (100), and the lens (200) is in contact with the contact portion (312).

3. The high-stability lens driven by a non-powered mechanism according to claim 2, characterized in that, A flexible sheet is provided between the contact portion (312) and the lens (200), the flexible sheet is fixed to the contact portion (312), and the lens (200) is in contact with the flexible sheet.

4. The high-stability lens driven by a non-powered mechanism according to claim 3, wherein The contact stress between the elastic arm and the lens (200) < 0.2 Mpa.

5. The power-free mechanically driven highly stable lens according to claim 1, wherein Each elastic arm group (300) includes at least three elastic arms, and the plurality of elastic arms are evenly distributed circumferentially around the first lens barrel (100).

6. The power-free mechanically-driven highly stable lens according to claim 1, wherein A plurality of damping post groups (400) are provided on the inner wall of the first lens barrel (100), each lens (200) is in contact with one damping post group (400), the plurality of damping post groups (400) are distributed along the axis of the first lens barrel (100), each damping post group (400) includes a plurality of damping posts, and in one damping post group (400), the plurality of damping posts are distributed circumferentially around the first lens barrel (100), the axis of the damping post is parallel to the axis of the first lens barrel (100), and the side wall of the damping post is in contact with the side wall of the lens (200).

7. The power-free mechanically-driven highly stable lens according to claim 6, wherein The damping post is a rubber post, and a metal sheet is embedded in the rubber post.

8. The power-free mechanically-driven highly stable lens according to claim 6, wherein Each damping post group (400) includes at least six damping posts, and the plurality of damping posts are evenly distributed circumferentially around the first lens barrel (100).

9. The power-free mechanically driven highly stable lens according to claim 1, wherein A second lens barrel (500) is sleeved outside the first lens barrel (100), the first lens barrel (100) and the second lens barrel (500) are coaxially arranged, a plurality of through threaded holes are provided on the side wall of the second lens barrel (500), the plurality of threaded holes are evenly distributed circumferentially around the second lens barrel (500), each threaded hole is provided with an adjusting screw (600), and the end of the adjusting screw (600) abuts against the outer side wall of the first lens barrel (100).

10. The power-free mechanically driven highly stable lens according to claim 1, characterized in that, A liquid metal is coated between the contact surface of the elastic arm and the lens (200). The liquid metal is in a solid state within the range of a first temperature threshold and in a liquid state within the range of a second temperature threshold. Among them, the lens (200) operates within the range of the first temperature threshold.

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