A fast cooling lens mounting structure with separated optical reference and heat transmission and its implementation method

Abstract

The present invention discloses a rapid cooling lens mounting structure and implementation method with separated optical reference and heat transfer, which is suitable for rapid cooling of deep-cold optical systems. The present invention is composed of a pressure ring, a lens seat annular surface heat-conducting layer, a lens annular surface heat-conducting layer, a lens, a fixed support, a lens seat and a pressure ring screw. The present invention sets up an optical reference mounting and heat transfer separation structure, and introduces a flexible structure and a specific design method. On the premise of ensuring that the optical reference ensures optical accuracy, it solves the problem of radial low-temperature shrinkage of the lens installation and avoids the influence of the mounting structure on the optical performance of the lens; by reserving a heat transfer pressing surface and heat transfer design, quantitative controllable rapid cooling time is obtained, and low-stress installation and rapid cooling of deep-cold lenses are realized. The present invention has a simple structure, convenient operation, good compatibility and high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of deep cryogenic lens installation, and specifically to a rapid cooling lens installation structure with separated optical reference and heat transmission and an implementation method thereof, which is suitable for assembling structures requiring rapid cooling and cold optical cryogenic machines. Background Art

[0002] In order to better meet the infrared detection needs of deep-space celestial bodies and low-energy targets in space, high sensitivity and low noise are inevitable development trends. Cold optical technology is one of the effective means to achieve this target detection. Cold optical technology places the optical elements and detectors of the infrared optical system in the rear optical path component (cold box / dewar), and uses a deep-cold cold source to reduce the temperature of the optical elements and detectors to the operating temperature, thereby effectively suppressing the impact of thermal radiation and stray light from the optical elements and their supporting structures on the detection performance, and greatly reducing background noise. At the same time, with the development of moving target and weak target detection, the demand for rapid cooling of the optical-mechanical system has gradually emerged. In the observation of certain infrared detection payloads, the system requires the low-temperature optical-mechanical system to be cooled to the required temperature in a short time, so as to reduce the instrument background in a short time and realize weak target detection at the same time.

[0003] The Chinese invention patent with announcement number CN103389554B discloses a multi-point support structure for supporting height-adjustable optical elements. The solution is that multiple flexible support components are evenly distributed and fixed on the inner circumferential surface of the frame, and the optical elements are arranged on multiple flexible support components. The flexible support components are composed of a flexible support block, a differential head and a restoring force spring. The differential head is fixed on the upper part of the flexible support block, and the restoring force spring is fixed on the upper part of the flexible support block and is located in the direction opposite to the differential head.

[0004] A Chinese invention patent with announcement number CN108227111B discloses a method for reducing the bonding stress of an aspheric large-aperture hollow reflector. During assembly, the main reflector and the main mirror frame are supported by a support platform, the main mirror is assisted in positioning by a main mirror pressure plate and a pressure plate rubber pad, and the main reflector is fixed by injecting glue through the glue injection hole.

[0005] Currently, domestic patents for lens assemblies focus on innovations in low-stress mounting structures for lens assemblies, generally employing micro-flexible structures to reduce the impact of mounting stress on the lens. Currently, domestic and international patents and articles do not report on lens assembly mounting structures that enable rapid cooling.

[0006] The processing and assembly of optical components and supporting structures must be performed at room temperature, but their actual operating environment ranges from 77K to 200K, with temperature fluctuations reaching 200K. Generally speaking, material performance parameters such as CTE (coefficient of linear thermal expansion), specific heat capacity, and refractive index vary from material to material, and these performance parameters change nonlinearly during the cooling process. Differences in geometric shape change are primarily due to differences in the CTE of the materials. This can cause positional errors and deformation of optical components, and even damage them. Optical changes are affected not only by differences in the geometric shape of the optical surface and changes in the position of the optical component, but also by changes in the refractive index of the optical material. Summary of the Invention

[0007] The purpose of the present invention is to provide a rapid cooling lens mounting structure and implementation method with separated optical reference and heat transmission, which solves the problem that the existing technology focuses on the innovation of the low-stress mounting structure of the lens group but does not explain how to achieve rapid cooling, and at the same time ignores the defects of rapid temperature changes, especially the impact of low temperature on the lens group structure.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A fast cooling lens mounting structure with separated optical reference and heat transmission, comprising a pressing ring, a lens and a lens seat, wherein the lens seat is provided with a mounting groove, and the lens is arranged in the mounting groove;

[0010] A fixed support is also provided in the mounting groove, and the lens is provided on the fixed support;

[0011] The pressing ring is cylindrical with a folded edge, the folded edge is the pressing ring lens seat ring surface, and the cylinder wall is the pressing ring lens ring; the pressing ring is inserted into the installation groove, the pressing ring lens seat ring surface is mounted on the upper surface of the side wall of the installation handle, and the pressing ring lens ring presses against the upper surface of the lens;

[0012] An annular lens seat annular surface heat conducting layer is arranged between the pressing ring lens seat annular surface and the upper surface of the mounting groove side wall, and an annular lens annular surface heat conducting layer is arranged between the pressing ring lens ring and the lens.

[0013] The fixed support is in a circular ring shape and comprises a flexible support and a non-flexible support. The flexible support is arranged at intervals on the upper surface of the non-flexible support.

[0014] The pressure ring, fixed support and lens holder are made of high thermal conductivity material with a thermal conductivity greater than 150W / (m﹒K) and a coefficient of expansion less than 8.6×10 -6 / K;

[0015] A through hole is provided on the annular surface of the pressure ring lens seat, and a screw hole is provided on the lens seat wall accordingly. The pressure ring screw fixes the pressure ring on the lens seat through the through hole and the screw hole.

[0016] The lens seat annular surface heat-conducting layer and the lens annular surface heat-conducting layer are made of a material with a thermal conductivity greater than 70 W / (m﹒K).

[0017] The lens is convex and comprises a lens supporting surface and a lens heat conducting surface. The lens annular surface heat conducting layer is arranged on the lens heat conducting surface, and the lens supporting surface is arranged on the fixed support.

[0018] The method for confirming the diameter D2 of the lens heat conduction surface is as follows:

[0019]

[0020] Where Cv is the specific heat capacity of the lens, m is the mass of the lens, k is the thermal conductivity of the lens, H2 is the thickness of the lens, T is the cooling time of the lens, D1 is the inner diameter of the pressure ring, and D3 is the diameter of the lens.

[0021] The depth H5 of the mounting groove of the lens holder is equal to the sum of the lens ring depth H1 of the pressing ring, the edge thickness H2 of the lens and the thickness H3 of the fixed support, that is, H5=H1+H2+H3.

[0022] A method for implementing a fast cooling lens mounting structure with separation of optical reference and heat transmission,

[0023] Here’s how to do it:

[0024] Step 1: glue and align the lens seat ring surface heat-conducting layer and the pressure ring lens seat ring surface, and the lens ring surface heat-conducting layer and the pressure ring lens ring respectively under the alignment instrument, and set them aside after curing;

[0025] Step 2: Use an alignment tool to glue the fixed support and lens holder together and then cure them.

[0026] Step 3: Use three coordinates to measure the form and position tolerances of the fixed support and lens holder after curing in step 2, and use a machine tool to fine-tune them to the form and position tolerances required by optics, and ensure that the depth H5 of the mounting groove of the lens holder is equal to the sum of the depth H1 of the lens ring of the pressure ring, the edge thickness H2 of the lens, and the thickness H3 of the fixed support;

[0027] Step 4: Clean the fixed support and lens holder after finishing in step 3 with acetone and alcohol ultrasonically, and then put them into an oven for drying.

[0028] Step 5: Place the lens into the mounting groove of the lens holder processed in step 4 under the alignment instrument, and then center and glue and cure;

[0029] Step 6: Insert the pressure ring that has been cured in step 1 into the installation groove and fix it on the lens seat. The pressure ring fixes the lens on the lens seat.

[0030] A through hole is set on the annular surface of the pressure ring lens seat, and a corresponding screw hole is set on the lens seat; Step 6, insert the pressure ring into the installation slot, align the through hole on the annular surface of the pressure ring lens seat with the screw hole on the lens seat, and fix it with the pressure ring screw; first fix it with a torque of 4cN·m, then loosen it, tighten it with a torque of 2cN·m, and then back it off 1 / 8 of a turn, and fill the glue and solidify the pressure ring screw and the pressure ring.

[0031] The present invention conducts mechanical and thermal design for a lens mounting structure with rapid cooling. On the premise of ensuring the optical reference and optical accuracy, high thermal conductivity materials are selected as the materials for the lens seat and the pressure ring. A flexible structure is adopted on the mounting surface of the lens, and a heat transfer pressing surface is reserved on the front surface of the lens to separate the optical reference from the heat transfer, thereby realizing a low-stress, rapid cooling lens mounting structure.

[0032] The advantages of the present invention are: 1. The present invention has a simple structure, is easy to operate, and has low cost; 2. The diameter of the lens bonding surface in the present invention can be calculated based on the cooling time to guide the lens design; 3. The pressure ring, fixed support, and lens seat in the present invention are all made of high thermal conductivity materials, and the heat transfer interface is made of high thermal conductivity materials to achieve rapid cooling of the lens mounting structure; 4. Under the premise of ensuring the optical reference and optical accuracy, the present invention sets a flexible support in the fixed support to solve the radial resistance to low-temperature shrinkage of the lens installation, which can offset the deformation of the lens in the radial direction, thereby achieving low-stress installation of the lens and avoiding the influence of the installation structure on the optical performance of the lens; 5. In order to achieve rapid cooling, a heat transfer pressing surface is reserved on the front surface of the lens. The cross-sectional area of ​​the lens pressing surface is calculated based on the heat flux density, cooling time, and specific heat capacity to solve the quantitative controllable rapid cooling; 6. The lens group assembled by the present invention can be applied to the 80K temperature zone, and can also be applied to lower temperature zones below 80K. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a diagram of the lens installation structure of the present invention;

[0034] Figure 2 It is a schematic diagram of the structure of the pressing ring of the present invention;

[0035] Figure 3 This is a structural diagram of the heat-conducting layer on the annular surface of the lens holder of the present invention;

[0036] Figure 4 This is a structural diagram of the annular heat-conducting layer of the lens of the present invention.

[0037] Figure 5 2 is a diagram showing the structure of the lens of the present invention.

[0038] Figure 6 It is a fixed support structure diagram of the present invention.

[0039] Figure 7 It is a cross-sectional view of the fixed support of the present invention.

[0040] Figure 8 It is a structural diagram of the lens holder of the present invention.

[0041] In the figure: 1-pressing ring; 101-pressing ring lens seat ring surface; 102-pressing ring lens ring; 103-through hole; 2-lens seat ring surface heat-conducting layer; 3-lens seat ring surface heat-conducting layer; 4-lens, 401-lens supporting surface; 402-lens heat-conducting surface; 5-fixed support; 501-flexible support; 502-non-flexible support; 6-lens seat; 601-mounting slot; 602-screw hole; 7-pressing ring screw. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to the accompanying drawings, which are for illustrative purposes only and are not to be construed as limiting the present invention.

[0043] To more concisely illustrate this embodiment, some components well known to those skilled in the art but not relevant to the main content of this invention may be omitted from the drawings or descriptions. In addition, for ease of description, some components may be omitted, enlarged, or reduced in size in the drawings, but they do not represent the dimensions or entire structure of the actual product.

[0044] The present invention discloses a fast cooling lens installation structure with separated optical reference and heat transmission, such as Figure 1-8 As shown, it includes a pressing ring 1 , a lens 4 and a lens seat 6 . The lens seat 6 is provided with a mounting groove 601 , and the lens 4 is arranged in the mounting groove 601 .

[0045] A fixed support 5 is further provided in the mounting groove 601 , and the lens 4 is disposed on the fixed support 5 .

[0046] like Figure 1 、 Figure 2 As shown, the pressure ring 1 is cylindrical with a folded edge, the folded edge is the pressure ring lens seat annular surface 101, and the cylinder wall is the pressure ring lens ring 102; the pressure ring 1 is inserted into the mounting groove 601, the pressure ring lens seat annular surface 101 is mounted on the upper surface of the side wall of the mounting groove 601, and the pressure ring lens ring 102 is pressed against the upper surface of the lens 4; the pressure ring lens seat annular surface 101 is provided with a through hole 103, and the lens seat 6 is correspondingly provided with a screw hole 602, and the pressure ring screw 7 fixes the pressure ring 1 on the lens seat 6 through the through hole 103 and the screw hole 602.

[0047] Furthermore, the pressure ring 1, fixed support 5, and lens holder 6 are made of a high-thermal-conductivity material with a thermal conductivity greater than 150 W / (m﹒K) and a coefficient of expansion less than 8.6 × 10-6 / K. SiCp / Al is preferred, with a thermal conductivity of 210 W / (m﹒K) and a coefficient of expansion of 7.3 × 10-6 / K. This allows for rapid cooling.

[0048] An annular lens seat annular surface heat conducting layer 2 is provided between the pressure ring lens seat annular surface 101 and the upper surface of the side wall of the mounting groove 601 , and an annular lens annular surface heat conducting layer 3 is provided between the lower surface of the pressure ring lens ring 102 and the lens 4 .

[0049] The lens holder annular surface heat conducting layer 2 and the lens annular surface heat conducting layer 3 are made of a material with a thermal conductivity greater than 70W / (m﹒K). The thickness of the two layers is equal, 0.2mm-0.4mm. Indium is preferably used to achieve rapid cooling.

[0050] Further, if Figure 3 As shown, the width W3 of the lens seat annular surface heat conducting layer 2 is 0.2mm-0.4mm smaller than the width W1 of the pressure ring lens seat annular surface 101. Optionally, the width W1 of the pressure ring lens seat annular surface 101 is 5mm, and the width W3 of the lens seat annular surface heat conducting layer 2 is 4.8mm.

[0051] like Figure 4 As shown, the width W4 of the lens ring surface heat conducting layer 3 is 0.2mm-0.4mm smaller than the width W2 of the pressure ring lens ring 102. Optionally, the width W2 of the pressure ring lens ring 102 is 3mm, and the width W4 of the lens ring surface heat conducting layer 3 is 2.8mm.

[0052] like Figure 5 As shown, lens 4 is convex and made of ZnSe material. It includes a lens support surface 401 and a lens heat-conducting surface 402. The lens annular surface heat-conducting layer 3 is disposed between the lower surface of the pressure ring 102 and the lens heat-conducting surface 402. The lens support surface 401 is disposed above the fixed support 5. The flexible support 501 provides radial resistance to low-temperature shrinkage during installation of the lens 4, preventing the installation structure from affecting the optical performance of the lens 4. The arrangement of the lens heat-conducting surface 402 and the lens annular surface heat-conducting layer 3 enables rapid cooling.

[0053] The method for confirming the diameter D2 of the lens heat conducting surface 402 is as follows:

[0054] The cross-sectional area A of the lens heat conducting surface 402 is determined based on the specific heat capacity Cv, mass m, thermal conductivity k, thickness H2 of the lens 4, and cooling time T. A=C v ·m·H2k·T;

[0055] The diameter D2 of the lens heat conducting surface 402 is calculated based on the diameter D3 of the lens 4, the inner diameter D1 of the pressure ring 1 and the cross-sectional area A of the lens heat conducting surface 402.

[0056] like Figure 6 、 Figure 7As shown, the fixed support 5 is annular and includes a flexible support 501 and a non-flexible support 502. The flexible support 501 is spaced apart from the upper surface of the non-flexible support 502. Preferably, the fixed support 5 is made of a high thermal conductivity material with a thermal conductivity greater than 150W / (m﹒K) and an expansion coefficient less than 8.6×10 -6 / K, wherein the thickness of the non-flexible support 502 is 0.5mm-1mm smaller than the thickness of the flexible support 501. Optionally, the thickness of the flexible support 501 is 1mm, the thickness of the non-flexible support 502 is 2mm, and the total thickness of the fixed support 5 is 3mm.

[0057] like Figure 1 、 Figure 8 As shown, the depth H5 of the mounting groove 601 of the lens holder 6 is equal to the sum of the depth H1 of the pressing ring lens ring 102 of the pressing ring 1, the edge thickness H2 of the lens 4 and the thickness H3 of the fixed support 5, that is, H5=H1+H2+H3.

[0058] The above Figure 1-8 A method for implementing a fast cooling lens mounting structure with optical reference and heat transmission separated is provided, and the specific steps are as follows:

[0059] Step 1: glue and align the lens seat annular surface heat-conducting layer 2 and the pressure ring lens seat annular surface 101, and the lens annular surface heat-conducting layer 3 and the pressure ring lens ring 102 respectively under the alignment instrument, and set them aside after curing;

[0060] Step 2: align the fixed support 5 and the lens holder 6 with glue under the alignment instrument and cure;

[0061] Step 3: Use three coordinates to measure the form and position tolerances of the fixed support 5 and the lens holder 6 after curing in step 2, and use a machine tool to fine-tune them to the form and position tolerances required by optics, and ensure that the depth H5 of the mounting groove 601 of the lens holder 6 is equal to the sum of the depth H1 of the pressure ring lens ring 102 of the pressure ring 1, the edge thickness H2 of the lens 4, and the thickness H3 of the fixed support 5;

[0062] Step 4: After the fixed support 5 and lens holder 6 are finely trimmed in step 3, they are ultrasonically cleaned with acetone and alcohol, and then placed in an oven for drying;

[0063] Step 5: Place the lens 4 into the mounting groove 601 of the lens holder 6 processed in step 4 under the alignment instrument, and then glue and cure the lens 4 in the alignment instrument.

[0064] Step six: insert the pressing ring 1 that has been cured in step one into the mounting groove 601 and fix it on the lens holder 6 . The pressing ring 1 fixes the lens 4 on the lens holder 6 .

[0065] Furthermore, a through hole 103 is provided on the annular surface 101 of the pressure ring lens seat, and a screw hole 602 is correspondingly provided on the lens seat 6; in step six, after the pressure ring 1 is inserted into the mounting groove 601, the through hole 103 on the annular surface 101 of the pressure ring lens seat and the screw hole 602 on the lens seat 6 are aligned and fixed with the pressure ring screw 7; first fix it with a torque of 4 cN·m, then loosen it, tighten it with a torque of 2 cN·m, and then back off 1 / 8 of a turn, and fill the glue and solidify the pressure ring screw 7 and the pressure ring 1.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. That is, any equivalent changes and modifications made according to the content of the patent application of the present invention should fall within the technical scope of the present invention.

Claims

1. A fast cooling lens mounting structure with separated optical reference and heat transmission, comprising a pressure ring (1), a lens (4) and a lens seat (6), wherein the lens seat (6) is provided with a mounting groove (601), and the lens (4) is arranged in the mounting groove (601); Its characteristics are: A fixed support (5) is also provided in the mounting groove (601), and the lens (4) is provided on the fixed support (5); The pressing ring (1) is cylindrical with a folded edge, the folded edge is a pressing ring lens seat annular surface (101), and the cylinder wall is a pressing ring lens ring (102); the pressing ring (1) is inserted into the mounting groove (601), the pressing ring lens seat annular surface (101) is mounted on the upper surface of the side wall of the mounting groove (601), and the pressing ring lens ring (102) is pressed against the upper surface of the lens (4); An annular lens seat annular surface heat conducting layer (2) is provided between the pressure ring lens seat annular surface (101) and the upper surface of the side wall of the mounting groove (601), and an annular lens annular surface heat conducting layer (3) is provided between the pressure ring lens ring (102) and the lens (4); The lens (4) is convex, comprising a lens support surface (401) and a lens heat-conducting surface (402); the lens annular heat-conducting layer (3) is arranged on the lens heat-conducting surface (402); and the lens support surface (401) is arranged on the fixed support (5); The method for confirming the diameter D2 of the lens heat conducting surface (402) is as follows: Wherein, Cv is the specific heat capacity of the lens (4), m is the mass of the lens (4), k is the thermal conductivity of the lens (4), H2 is the thickness of the lens (4), T is the cooling time of the lens (4), D1 is the inner diameter of the pressing ring (1), and D3 is the diameter of the lens (4).

2. The rapid cooling lens mounting structure with separated optical reference and heat transmission according to claim 1, characterized in that: The fixed support (5) is annular and comprises a flexible support (501) and a non-flexible support (502). The flexible support (501) is spaced apart on the upper surface of the non-flexible support (502).

3. The rapid cooling lens mounting structure with separated optical reference and heat transmission according to claim 2, characterized in that: The pressing ring (1), the fixed support (5) and the lens holder (6) are made of a high thermal conductivity material, the thermal conductivity of which is greater than 150W / (m﹒K) and the expansion coefficient is less than 8.6×10 -6 / K; The annular surface (101) of the pressure ring lens seat is provided with a through hole (103), and the lens seat (6) is correspondingly provided with a screw hole (602). The pressure ring screw (7) fixes the pressure ring (1) on the lens seat (6) through the through hole (103) and the screw hole (602).

4. The rapid cooling lens mounting structure with separated optical reference and heat transmission according to claim 3, characterized in that: The lens seat annular surface heat-conducting layer (2) and the lens annular surface heat-conducting layer (3) are made of a material with a thermal conductivity greater than 70W / (m﹒K).

5. The rapid cooling lens mounting structure with separated optical reference and heat transmission according to claim 1, characterized in that: The depth H5 of the mounting groove (601) of the lens seat (6) is equal to the sum of the depth H1 of the pressure ring lens ring (102) of the pressure ring (1), the edge thickness H2 of the lens (4) and the thickness H3 of the fixed support (5), that is, H5=H1+H2+H3.

6. The method for implementing the fast cooling lens mounting structure with separated optical reference and heat transmission according to any one of claims 1 to 5, characterized in that: Here’s how to do it: Step 1: glue and align the lens seat annular surface heat-conducting layer (2) and the pressure ring lens seat annular surface (101), and the lens annular surface heat-conducting layer (3) and the pressure ring lens ring (102) respectively under the centering instrument, and set them aside for use after curing; Step 2: glue the fixed support (5) and the lens holder (6) together and center them under the centering instrument, and then cure them; Step 3: Use three coordinates to measure the form and position tolerances of the fixed support (5) and the lens seat (6) after curing in step 2, and use a machine tool to fine-tune them to the form and position tolerances required by optics, and ensure that the depth H5 of the mounting groove of the lens seat (6) is equal to the sum of the depth H1 of the pressure ring lens ring (102) of the pressure ring (1), the edge thickness H2 of the lens (4) and the thickness H3 of the fixed support (5); Step 4: clean the fixed support (5) and lens holder (6) after fine-tuning in step 3 with acetone and alcohol ultrasonically, and then put them into an oven for drying; Step 5: Place the lens (4) into the mounting groove (601) of the lens holder (6) processed in step 4 under a centering instrument, and perform centering, gluing, and curing. Step six, insert the pressing ring (1) that has been cured in the installation step one into the installation groove (601) and fix it on the lens seat (6), and the pressing ring (1) fixes the lens (4) on the lens seat (6).

7. The method for implementing the fast cooling lens mounting structure with separated optical reference and heat transmission according to claim 6, characterized in that: The annular surface (101) of the pressure ring lens seat is provided with a through hole (103), and the lens seat (6) is provided with a corresponding screw hole (602); Step 6, the pressure ring (1) is inserted into the mounting groove (601), the through hole (103) of the annular surface (101) of the pressure ring lens seat is aligned with the screw hole (602) on the lens seat (6), and fixed with a pressure ring screw (7); first fix it with a torque of 4 cN·m, then loosen it, tighten it with a torque of 2 cN·m, and then retreat 1 / 8 of a turn, and fill the pressure ring screw (7) and the pressure ring (1) with glue and solidify it.

Images