Optical lens assembly capable of achieving rapid cooling

Abstract

The invention discloses an optical lens assembly capable of realizing rapid cooling, which belongs to the field of low-temperature infrared optics and comprises a lens barrel, a pressing ring and an optical lens element. The outer side of the circumference of the lens barrel is provided with a heat conduction installation platform, the contact area with a cold chain is increased, the contact face of the heat conduction installation platform and the cold chain is filled with indium sheets and pressed through screws to enhance heat transfer, the installation face of the heat conduction installation platform and the pressing ring is provided with threaded holes, and heat conduction resistance between the lens barrel and the pressing ring is reduced by filling the indium sheets. A step plane with the width of 2-3mm is designed on the circumferential edge of the optical lens element and is tightly pressed with the indium sheet filled on one surface of the pressing ring; the other surface of the optical lens element is circumferentially provided with a positioning step surface to ensure the installation precision. According to the invention, the step surface is arranged on the optical lens element to reduce the influence of installation stress on the surface type of the mirror surface, and meanwhile, the indium sheets and the pre-tightening force are filled to reduce the heat conduction resistance on a heat conduction link, so that the cooling time of the optical element is shortened, and the purpose of rapid cooling is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of low-temperature infrared optics, and in particular relates to an optical lens assembly capable of achieving rapid cooling. Background Art

[0002] Infrared detection instruments play an important role in aerospace. The background thermal noise caused by the optical system and components in the field of view of the detection instrument seriously affects the detection sensitivity of the instrument. Therefore, a low-temperature optical system is needed to reduce the thermal radiation of the optical system. For lens assemblies, in order to ensure precise positioning and lens surface shape, the cooling capacity of the refrigerator is currently mainly transferred to the lens barrel through a cold chain, and the optical lens is cooled by radiation. The cooling time usually takes several days. In applications related to high-speed flight platforms, the cooling speed of the optical system becomes a key factor restricting the response speed of the infrared camera. Therefore, a method of quickly achieving low-temperature optics is urgently needed. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides an optical lens assembly that can achieve rapid cooling. By designing a heat-conducting mounting surface on the circumferential surface of the lens, filling it with high thermal conductivity materials such as indium sheets, and applying a quantitative torque through testing, the heat-conducting installation of the lens assembly can be achieved while ensuring the precise positioning and high-precision surface shape of the infrared optical lens, thereby reducing the thermal resistance between the transmission cold chain and the lens assembly, and meeting the needs of rapid cooling of the optical system.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An optical lens assembly for achieving rapid cooling comprises a lens barrel, a pressure ring, and an optical lens element; the optical lens element is connected and fixed to the lens barrel via the pressure ring; a heat-conducting mounting platform is provided on the circumferential outer side of the lens barrel, and an indium sheet is filled on the contact surface of the heat-conducting mounting platform with the cold chain, and is compressed by screws to enhance heat transfer; a second threaded hole is provided on the contact surface between the lens barrel and the pressure ring, and the heat-conducting thermal resistance between the lens barrel and the pressure ring is reduced by filling the indium sheet; a step plane is provided on the circumferential edge of one side of the optical lens element, and an indium sheet is filled and compressed on the side where the step plane contacts the pressure ring; a positioning step surface is provided on the circumference of the other side of the optical lens element to ensure the installation accuracy of the optical lens element; the heat-conducting mounting platform, the lens barrel, the pressure ring, and the optical lens element constitute a heat-conducting link, and the pre-tightening force of the indium sheet and the compression of the screws reduces the heat-conducting thermal resistance on the heat-conducting link.

[0006] Furthermore, the width of the step plane is 2-3 mm.

[0007] Furthermore, the optical lens element has two side mirror surfaces, which are optically processed and coated, and the roughness of the step plane is less than 0.08 mm, and the circumferential width of the step plane is constant.

[0008] Furthermore, the pressure ring is machined to form a step structure, which includes a lower step surface and an upper step surface. The roughness of the lower step surface and the upper step surface is less than 0.1 mm, and they are parallel to each other; the lower step surface is installed in contact with the step plane; the upper step surface is installed in contact with the contact surface between the lens barrel and the pressure ring.

[0009] Furthermore, eight second threaded holes are provided on the upper circumference of the upper step surface, and the upper step surface and the lower step surface of the pressure ring are respectively in contact with the lens barrel and the optical lens element through threaded connection.

[0010] Furthermore, the lens barrel is provided with at least one heat-conducting mounting platform on the outer circumference thereof, and is provided with four first threaded holes; the inner circumference of the lens barrel is in contact with a positioning step surface for mounting and positioning the optical lens element.

[0011] Furthermore, the optical lens element and the pressure ring are clearance-fitted in the circumferential direction.

[0012] Furthermore, an indium sheet with a thickness of 0.05 mm is filled on the contact surface between the step plane, the lens barrel and the pressure ring, and the indium sheet is pressed by bolts.

[0013] Furthermore, there is a periphery between the optical lens element and the pressure ring, and low-temperature thermal conductive glue is filled in sections between the optical lens element and the periphery. Silver powder is pre-mixed in the low-temperature thermal conductive glue, and the low-temperature thermal conductive glue is evenly dotted in 4-6 sections along the circumference of the periphery.

[0014] Furthermore, there are multiple optical lens elements.

[0015] Beneficial effects:

[0016] 1. The present invention proposes designing a heat-conducting mounting platform on the radial edge of the optical lens element. The platform is on the circumference outside the light-clearance and has a radial length of approximately 2-3 mm. The step surface is a smooth plane with a surface roughness of less than 0.08 mm and is parallel to the pressure ring, thereby ensuring the contact area between the pressure ring and the lens and not directly contacting the lens surface, thereby reducing the impact of installation stress on the optical mirror surface.

[0017] 2. The present invention designs a pressure ring with a flanged or machined step structure, with the surface roughness of the upper and lower steps less than 0.1mm and parallel to each other. The lower step surface is mounted in contact with the optical lens element, with a circumferential width of 2-3mm and a uniform width on the circumference, ensuring a consistent contact area per unit length of the lens assembly. This ensures that the cooling energy is transferred to the optical lens element uniformly from all directions of the circumference, thereby improving the temperature uniformity on the optical element. The upper step surface is mounted in contact with the lens barrel, with a circumferential width of 5-6mm, also ensuring a uniform circumferential width. The upper step surface is designed with 8 threaded holes in a circumferential array, which are screwed together to make the upper and lower step surfaces of the pressure ring contact the lens barrel and the lens assembly, respectively.

[0018] 3. The present invention fills indium sheets on the contact surfaces between the optical lens element and the pressure ring, and between the pressure ring and the lens barrel, and compresses the indium sheets through threaded connections. The soft texture and strong ductility of the indium sheets are utilized to fill microscopic gaps, thereby reducing the contact thermal resistance on the heat transfer link, enhancing the heat transfer performance, reducing the cooling and temperature control time of the optical element, and achieving rapid cooling. At the same time, the indium sheet is used to buffer the stress generated by the direct contact between the lens and the pressure ring, thereby ensuring that the optical element is accurately positioned and the surface shape remains unchanged.

[0019] 4. The optical lens element and the pressure ring of the present invention have a circumferential clearance fit of approximately 0.2-0.3 mm, ensuring that there is no contact stress-induced deformation between the optical lens element and the pressure ring in high and low temperature environments. The circumferential gap between the optical lens element and the pressure ring is filled in sections with low-temperature thermally conductive adhesive. Specifically, silver powder is pre-mixed into the low-temperature adhesive to enhance thermal conductivity. The thermally conductive adhesive is evenly applied in 4-6 sections along the circumference to ensure circumferential clearance. This improves heat transfer performance while preventing excessive deformation of the lens assembly and the pressure ring material due to differences in thermal expansion coefficients under high and low temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an outline diagram of an optical lens assembly for achieving rapid cooling according to the present invention;

[0021] Figure 2 A cross-sectional view and a partially enlarged view of an optical lens assembly for achieving rapid cooling according to the present invention;

[0022] Figure 3 is an outline drawing of an optical lens element;

[0023] Figure 4 is a schematic diagram of an optical lens element;

[0024] Figure 5 is a cross-sectional view of an optical lens element;

[0025] Figure 6 It is the main view of the optical lens element.

[0026] Among them, the accompanying drawings are marked as: lens barrel 1, pressure ring 2, optical lens element 3, thermal conductive mounting platform 11, first threaded hole 12, second threaded hole 21, positioning step surface 41, contact surface 42, step plane 43, periphery 44, low-temperature thermal conductive glue 5. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0028] like Figures 1-6 As shown, an optical lens assembly for achieving rapid cooling of the present invention comprises a lens barrel 1, a pressure ring 2, and an optical lens element 3. The spacing between the multiple optical lens elements 3 is determined according to the design requirements of the optical system.

[0029] like Figure 2 As shown, the optical lens element 3 is spherical, with the concave side of the sphere in parallel contact with the lens barrel 1, forming a positioning step surface 41. A high-flatness step surface is machined into the lens barrel 1, which contacts the positioning step surface 41, ensuring precise positioning of the optical lens element 3. To reduce the impact of axial pressure on the lens' spherical surface, a stepped surface 43 is designed on the circumferential edge of the convex side of the sphere. This step surface 43 contacts the pressure ring 2 and is secured by screws, ensuring that the optical lens element 3 is mounted between the lens barrel 1 and the pressure ring 2. A thermally conductive mounting platform 11 is provided on the outer circumference of the lens barrel 1 to increase the contact area with the cold chain. The contact surface of the thermally conductive mounting platform 11 with the cold chain is filled with indium sheets and tightened with screws to enhance heat transfer. A second threaded hole 21 is provided in the contact surface 42 between the lens barrel 1 and the pressure ring 2. This indium sheet is filled with indium sheets to reduce the thermal resistance between the lens barrel 1 and the pressure ring 2. A periphery 44 is defined between the optical lens element 3 and the pressure ring 2 .

[0030] A stepped plane 43 is provided on the circumferential edge of the optical lens element 3, and the stepped plane 43 is pressed against one side of the pressing ring 2 by filling indium sheet; a positioning stepped surface 41 is provided on the other circumference of the optical lens element 3 to ensure the installation accuracy of the optical lens element 3.

[0031] The present invention uses a heat-conducting link consisting of a heat-conducting mounting platform 11, a lens barrel 1, a pressure ring 2, and an optical lens element 3, and designs a stepped plane 43 on the optical lens element 3 to reduce the influence of the installation stress on the mirror surface shape. At the same time, filling indium sheets and increasing the pre-tightening force reduce the heat-conducting thermal resistance on the heat-conducting link, shortening the cooling time of the optical lens element, and achieving the purpose of rapid cooling.

[0032] The mirror surfaces of the optical lens element 3 undergo optical treatment and coating, resulting in high optical transmittance within the applicable optical spectrum, meeting the optical aperture required by the optical system. Preferably, the present invention provides a stepped surface 43 2-3 mm outside the aperture of an optical lens element 3 with a diameter of 50-100 mm. The stepped surface 43 has a roughness of less than 0.08 mm and a constant circumferential width.

[0033] Preferably, the pressure ring 2 is of a flanged type and is preferably machined into a stepped structure. The upper and lower surfaces of the stepped structure are respectively an upper stepped surface and a lower stepped surface, each with a roughness of less than 0.1 mm and parallel to each other. The lower stepped surface is mounted in contact with the stepped plane 43. Preferably, the circumferential width of the contact surface is 2-3 mm, and the circumferential width is uniform, ensuring that the contact area of ​​the optical lens element 3 per unit length of the circumference is consistent; the upper stepped surface is mounted in contact with the contact surface 42, and the circumferential width of the contact surface is 5-6 mm, also ensuring that the circumferential width is uniform. Eight second threaded holes 21 are evenly arranged on the circumference of the upper stepped surface. The upper and lower stepped surfaces of the pressure ring 2 are respectively in contact with the lens barrel 1 and the optical lens element 3 through screw connection.

[0034] Preferably, the lens barrel 1 is provided with at least one thermally conductive mounting platform 11 on the outer circumference, with four first threaded holes 12 evenly spaced. The thermally conductive mounting platform 11 is connected to the hot end of the refrigerator's cold platform to transfer cooling capacity and reduce the contact thermal resistance between the refrigerator's cold platform and the lens barrel 1. The contact surface between the refrigerator's cold platform (not shown) and the lens barrel 1 is filled with indium sheets and secured with screws.

[0035] Preferably, the widths of the positioning step surface 41 , the contact surface 42 and the step plane 43 on the optical lens element 3 , the pressure ring 2 and the lens barrel 1 can be adjusted according to the aperture of the optical lens element 3 and the cooling requirement.

[0036] Preferably, 0.05 mm indium sheets are filled on the step plane 43 and the contact surface 42, and the indium sheets are pressed by screws. The soft texture and strong ductility of the indium sheets are used to fill the microscopic gaps, reduce the contact thermal resistance on the heat conduction link, and enhance the heat transfer performance.

[0037] Preferably, a 2 cNm torque is applied axially to the screw of each second threaded hole 21 on the pressing ring 2, and the surface profile change RMS of the optical lens element is ≤ , where RMS is the surface error, The wavelength is such that the contact surfaces among the lens barrel 1, the pressure ring 2 and the optical lens element 3 can achieve good heat conduction, while ensuring that the positioning accuracy and the surface shape of the optical lens element 3 remain unchanged.

[0038] Preferably, the filling material on the contact surface 42 and the step plane 43 is not limited to high thermal conductivity, soft material such as indium sheet and copper sheet, and the material thickness is 0.01-0.1 mm.

[0039] Preferably, the optical lens element 3 and the pressing ring 2 are fitted with a clearance in the circumferential direction, and the clearance is about 0.2-0.3 mm, to ensure that there is no contact stress between the optical lens element 3 and the pressing ring 2 in the circumferential direction causing deformation in high and low temperature environments.

[0040] Preferably, the periphery 44 between the optical lens element 3 and the pressing ring 2 is filled with low-temperature thermal conductive glue 5 in sections, such as Figure 2 As shown, silver powder is pre-mixed into the low-temperature thermal conductive adhesive 5 to enhance thermal conductivity, and the low-temperature thermal conductive adhesive 5 is evenly dotted in 4-6 sections along the circumference of the periphery 44 to ensure circumferential clearance, thereby improving the heat transfer performance while avoiding excessive deformation of the materials of the optical lens element 3 and the pressure ring 2 due to the difference in thermal expansion coefficient under high and low temperature conditions.

[0041] Preferably, the present invention provides a method for achieving rapid heat transfer between the lens barrel 1, the pressure ring 2 and the optical lens element 3 through an indium sheet, a low-temperature thermal conductive adhesive and a thread, which can be applied to a single optical element, such as Figure 4 As shown, it can also be applied to an optical lens assembly composed of multiple optical lens elements, such as Figure 1 As shown, it is a lens group composed of three optical lens elements. At the same time, it is not limited to application in lens assemblies or reflector assemblies.

Claims

1. An optical lens assembly for achieving rapid cooling, characterized in that: It comprises a lens barrel, a pressing ring, and an optical lens element; the optical lens element is connected and fixed to the lens barrel through the pressing ring; a heat-conducting mounting platform is provided on the outer circumference of the lens barrel, and an indium sheet is filled on the contact surface between the heat-conducting mounting platform and the cold chain, and is pressed by screws to enhance heat transfer; a second threaded hole is provided on the contact surface between the lens barrel and the pressing ring, and the heat-conducting thermal resistance between the lens barrel and the pressing ring is reduced by filling the indium sheet; a step plane is provided on the circumferential edge of one side of the optical lens element, and an indium sheet is filled and pressed on the side where the step plane contacts the pressing ring; a positioning step surface is provided on the circumference of the other side of the optical lens element to ensure the installation accuracy of the optical lens element; The heat-conducting mounting platform, the lens barrel, the pressing ring, and the optical lens element constitute a heat-conducting link, and the pre-tightening force of the indium sheet and the screws reduces the heat-conducting thermal resistance on the heat-conducting link.

2. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: The width of the step plane is 2-3 mm.

3. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: The optical lens element has mirror surfaces on both sides, the mirror surfaces on both sides are optically processed and coated, the roughness of the step plane is less than 0.08mm, and the circumferential width of the step plane is constant.

4. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: The pressure ring is machined to form a step structure, which includes a lower step surface and an upper step surface. The roughness of the lower step surface and the upper step surface is less than 0.1 mm and they are parallel to each other. The lower step surface is installed in contact with the step plane; the upper step surface is installed in contact with the contact surface between the lens barrel and the pressure ring.

5. The optical lens assembly for achieving rapid cooling according to claim 4, characterized in that: The upper circumference of the upper step surface is provided with 8 second threaded holes, and the upper step surface and the lower step surface of the pressing ring are respectively in contact with the lens barrel and the optical lens element through threaded connection.

6. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: The lens barrel is provided with at least one heat-conducting mounting platform on the outer circumference thereof, and is provided with four first threaded holes; the inner circumference of the lens barrel contacts the positioning step surface, which is used for the installation and positioning of the optical lens element.

7. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: The optical lens element and the pressure ring are clearance-matched in the circumferential direction.

8. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: An indium sheet with a thickness of 0.05 mm is filled on the contact surface between the step plane, the lens barrel and the pressure ring, and the indium sheet is pressed tightly by bolts.

9. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: There is a periphery between the optical lens element and the pressing ring, and low-temperature thermal conductive glue is filled in sections between the optical lens element and the periphery. Silver powder is premixed in the low-temperature thermal conductive glue, and the low-temperature thermal conductive glue is evenly dotted in 4-6 sections along the circumference of the periphery.

10. The optical lens assembly for achieving rapid cooling according to claim 1, characterized in that: The number of the optical lens elements is multiple.

Images