A liquid-cooled silicon carbide reflector structure

Abstract

A liquid-cooled silicon carbide reflector structure belongs to the technical field of silicon carbide reflectors. It solves the technical problem in the prior art that the temperature of the reflector rises rapidly and the thermal deformation is large when high-power lasers are used. The liquid-cooled silicon carbide reflector structure of the present invention includes a silicon carbide substrate, an outlet plug, a cavity sealing plate, an inlet sealing plate, an inlet plug, an outlet sealing plate and a coolant. The mirror body of the reflector is made of silicon carbide material and is provided with a liquid cooling channel on the back. Under the condition of high-power laser irradiation, based on the high thermal conductivity of the silicon carbide material, the heat of the mirror surface is quickly conducted to the back, and then the heat is taken away by the high viscosity of the coolant. Therefore, the temperature rise of the mirror surface can be suppressed and the temperature gradient of the mirror body can be reduced, thereby ensuring that the reflector can maintain a high surface accuracy. In addition, the reflector structure is compact and reliable, and the cooling efficiency is high. It is particularly suitable for optical systems of high-power Gaussian lasers.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon carbide mirrors, and particularly relates to a liquid-cooled silicon carbide mirror structure, which is particularly suitable for high-power laser applications. Background Art

[0002] The laser emission telescope is responsible for expanding and emitting high-power laser to the target, and the optical mirror is the core component of the laser emission telescope. With the progress of laser technology, especially fiber laser technology, the laser emission power is continuously increasing, and the laser power density acting on the optical mirror can reach dozens of kW / cm 2 , such high-intensity laser incidence will cause the temperature of the mirror to rise rapidly, resulting in a large temperature gradient in the mirror body and thermal deformation. The surface shape accuracy of the mirror will drop sharply, ultimately leading to the degradation of the output beam quality of the laser emission telescope and seriously affecting the optical performance of the system. Summary of the Invention [[ID=1৪]]

[0003] The object of the present invention is to solve the technical problems in the prior art that in the case of high-power laser applications, the temperature of the mirror rises rapidly and the thermal deformation is large, and to provide a liquid-cooled silicon carbide mirror structure. The liquid-cooled silicon carbide mirror structure can take away the heat absorbed by the silicon carbide mirror through the circulating flow of the coolant in the silicon carbide mirror, thereby suppressing the temperature rise of the silicon carbide mirror, improving the surface shape accuracy of the silicon carbide mirror, and further ensuring the beam quality of the system.

[0004] The technical solutions adopted by the present invention to solve the above technical problems are as follows.

[0005] The present invention provides a liquid-cooled silicon carbide mirror structure, which includes a silicon carbide substrate, an outlet plug, a cavity sealing plate, an inlet sealing plate, an inlet plug, an outlet sealing plate and a coolant;

[0006] The silicon carbide substrate is composed of a mirror body and a back plate. The back surface of the mirror body is a lightweight cavity structure, and the lightweight cavity structure is a circular ring radial structure, which is composed of N circular ring rib plates arranged in sequence from the inside to the outside, N≥3, and there are P circular ring rib plates respectively provided with a number of through holes independently, P<N. M vertical rib plates are independently fixed between adjacent two circular ring rib plates, and M fan-shaped cavities are independently divided between adjacent two circular ring rib plates, M≥3, and there are Q vertical rib plates provided with through holes, Q<M; the through holes on the circular ring rib plates and the through holes on the vertical rib plates form one or more coolant circulation paths; the back plate is hermetically fixed on the back surface of the mirror body, and a central through hole and a number of connection holes are opened on the outer surface. The central through hole is aligned with the inner wall of the top opening of the innermost circular ring rib plate, and each fan-shaped cavity is communicated with a connection hole;

[0007] The innermost annular rib plate is provided with an annular step structure, the inlet sealing plate is disc-shaped and cooperates with the annular step structure, and is sealed and installed on the annular step structure to form a sealed central cavity, and the top surface of the inlet sealing plate is at a lower height than the top surface of the innermost annular rib plate, and an inlet plug mounting hole is provided on the inlet sealing plate;

[0008] The inlet plug is sealed and fixed on the inlet plug mounting hole;

[0009] There are one or more outlet sealing plates, which are sealed on the connecting holes of the fan-shaped cavity at the end of each coolant flow path, and the outlet sealing plates are provided with outlet plug mounting holes;

[0010] The number of the outlet plugs is equal to the number of the outlet sealing plates, and each outlet plug is installed on an outlet plug installation hole;

[0011] The remaining connection holes on the fan-shaped cavity connected to the through hole are sealed with the cavity sealing plate;

[0012] The cooling liquid enters the central cavity through the inlet plug, flows in the fan-shaped cavity through the through holes, and finally flows out through the outlet plug.

[0013] Furthermore, the precision of the mirror body is better than 2nm, and the cylindricity of the innermost annular rib is better than 0.005mm.

[0014] Furthermore, the lightweight cavity structure is composed of four annular ribs arranged in sequence from the inside to the outside, the innermost layer is the first annular rib, six first vertical ribs are arranged between the second annular rib and the first annular rib, and six fan-shaped cavities are divided, twelve second vertical ribs are arranged between the third annular rib and the second annular rib, and twelve fan-shaped cavities are divided, eighteen third vertical ribs are arranged between the fourth annular rib and the third annular rib, and eighteen fan-shaped cavities are divided, and six of the first vertical rib, the second vertical rib and the third vertical rib are respectively on the same direct line, three of which are A straight line divides the back of the mirror body into three 120° sector-shaped areas. A first through hole is provided on the first circular rib plate corresponding to each 120° sector-shaped area, and a second through hole is provided on the corresponding second circular rib plate. The second through hole and the first through hole are respectively connected to the two sector-shaped cavities, and a third through hole is provided on the vertical rib plate between the two sector-shaped cavities. Fourth through holes are provided on the vertical rib plates between the four sector-shaped cavities of the corresponding second circular rib plate and the third circular rib plate, and the connecting hole on the sector-shaped cavity farthest from the second through hole is sealed with an outlet sealing plate, and the connecting holes on the remaining sector-shaped cavities are sealed with cavity sealing plates.

[0015] Furthermore, the connection holes corresponding to the outermost fan-shaped cavity are all fan-shaped, and the connection holes corresponding to the fan-shaped cavity between the innermost circular annular rib plate and the outermost fan-shaped cavity are all circular.

[0016] Furthermore, the mirror body and the back plate are integrally formed.

[0017] Furthermore, the sealing plate, the inlet sealing plate and the outlet sealing plate are all fixed by bonding.

[0018] Furthermore, the sealing plate, the inlet sealing plate and the outlet sealing plate are all made of indium steel.

[0019] Furthermore, the inlet plug is connected to the outlet of the water cooler through a hose, and the outlet plug is connected to the inlet of the water cooler through a hose, and both connection interfaces use standard airtight sealing rings.

[0020] Furthermore, the coolant is ethylene glycol.

[0021] Furthermore, the flow rate of the cooling liquid is 1 to 2 L / min.

[0022] The principle of the present invention is as follows: the present invention uses silicon carbide material as the reflector substrate and designs a mirror structure with a liquid cooling circulation channel. In terms of mirror material, compared with glass materials such as fused quartz and ULE, silicon carbide has unique advantages. First, silicon carbide has a high specific stiffness, and the mirror body is not easily deformed by gravity. It is also lightweight, which allows the development of a lightweight and stable reflector. Second, silicon carbide has a high thermal conductivity, which allows the heat absorbed by the reflective surface of the mirror body to be quickly transferred to the back of the mirror body. It is very suitable for introducing a series of active cooling methods such as liquid cooling, air cooling, and semiconductor cooling behind the mirror body. Taking into account the low cooling efficiency of air cooling and semiconductor cooling, and the poor working continuity and continuity of phase change cooling, the present invention designs a liquid cooling circulation channel on the lightweight structure of the back of the silicon carbide reflector. The coolant flows into the central cavity of the mirror body, flows in the liquid cooling circulation channel, and finally flows out through the outlet plug. When the mirror is irradiated by high-power laser, the high thermal conductivity of the mirror body and the high viscosity and thermal properties of the coolant can take away the heat of the mirror body. Therefore, the temperature rise of the mirror surface can be suppressed and the temperature gradient of the mirror body can be reduced, thereby ensuring that the silicon carbide mirror can maintain a high surface accuracy.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The liquid-cooled silicon carbide reflector structure of the present invention has a relatively simple and compact mirror body structure, and the mirror body structural components are easy to process and assemble. The mirror body material is selected from silicon carbide material with high specific stiffness, high thermal conductivity, and low thermal expansion coefficient, and the coolant is selected from ethylene glycol solution with high viscosity and thermal properties. When strong light is incident on the reflector, the coolant in the mirror body starts a circulation flow mode. Through the circulation of the coolant inside the mirror body, the heat absorbed by the mirror body of the silicon carbide reflector under high-power laser irradiation can be quickly taken away by the coolant, thereby suppressing the temperature rise and temperature gradient of the reflector, and ensuring that the reflector always maintains high surface accuracy.

[0025] The liquid-cooled silicon carbide reflector structure of the present invention has high cooling efficiency and long continuous working time. It can maintain high surface accuracy of the reflector under the condition of long-term incidence of high-power laser, thereby ensuring the imaging quality of the optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of the back side of the liquid-cooled silicon carbide reflector of the present invention;

[0028] Figure 2 for Figure 1 A central cross-sectional view of

[0029] Figure 3 This is an internal cross-sectional view of the mirror body of the liquid-cooled silicon carbide reflector structure of the present invention.

[0030] In the figure: 1 is the silicon carbide substrate, 1-1 is the mirror body, 1-2 is the back plate, 2 is the outlet plug, 3 is the cavity sealing plate, 4 is the inlet sealing plate, 5 is the inlet plug, 6 is the outlet sealing plate, and 7 is the coolant. DETAILED DESCRIPTION

[0031] In order to further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0032] like Figures 1 to 3As shown in the figure, the liquid-cooled silicon carbide mirror structure of the present invention includes a silicon carbide substrate 1, an outlet plug 2, a cavity sealing plate 3, an inlet sealing plate 4, an inlet plug 5, an outlet sealing plate 6, and a coolant 7. Among them, the silicon carbide substrate 1 consists of a mirror body 1-1 and a back plate 1-2. The back of the mirror body 1-1 is a lightweight cavity structure, and the lightweight cavity structure is a circular ring radiation type structure, which is composed of N circular ring rib plates arranged in sequence from the inside to the outside, N≥3, and P circular ring rib plates are respectively provided with a plurality of through holes independently, P<N. M vertical rib plates are independently fixed between two adjacent circular ring rib plates, M≥3, and M fan-shaped cavities are independently divided between two adjacent circular ring rib plates, and Q vertical rib plates are provided with through holes, Q<M. The through holes on the circular ring rib plates and the through holes on the vertical rib plates form one or more coolant flow paths. The back plate 1-2 is hermetically fixed on the back of the mirror body 1-1, and a central through hole and a plurality of connection holes are opened on the outer surface. The central through hole is aligned with the inner wall of the top opening of the innermost circular ring rib plate, and each fan-shaped cavity is communicated with a connection hole. A circular ring step structure is opened on the innermost circular ring rib plate. The inlet sealing plate 4 is disc-shaped and is matched with the circular ring step structure and is hermetically installed on the circular ring step structure to form a sealed central cavity. The height of the top surface of the inlet sealing plate 4 is lower than the height of the top surface of the innermost circular ring rib plate. An inlet plug mounting hole is opened on the inlet sealing plate 4. The inlet plug 5 is installed on the inlet plug mounting hole. The outlet sealing plate 6 is one or more, and is sealed on the connection hole on the fan-shaped cavity at the end of the coolant flow path. An outlet plug mounting hole is opened on the outlet sealing plate 6. The number of outlet plugs 2 is equal to the number of outlet sealing plates 6, and each outlet plug 2 is installed on an outlet plug mounting hole. The connection holes on the remaining fan-shaped cavities communicated with the through holes are sealed by the cavity sealing plate 3. The coolant 7 enters the central cavity through the inlet plug 5, flows in the fan-shaped cavity through the through hole, and finally flows out through the outlet plug 2. The specific processing position of the through hole is formulated according to the flow direction and rules of the coolant 7.

[0033] In the above technical solution, the mirror body 1-1 is sintered from a silicon carbide material with high specific stiffness, high thermal conductivity, and low thermal expansion rate. The reflecting surface is processed by a super-smooth surface processing technology and is finely polished by surface modification to make its surface roughness better than 2nm. After the reflecting surface is finely polished, a laser high-reflection film is plated. There is no special limit on the size of the mirror body 1-1. For example, a diameter of 500mm and a thickness of 5mm can be adopted. The thickness of the circular ring rib plate is preferably 6mm, and the thickness of the vertical rib plate is preferably 3mm.

[0034] In the above technical solution, the back of the mirror body 1-1 is preferably a lightweight cavity structure composed of four annular ribs arranged in sequence from the inside to the outside, the innermost layer is the first annular rib, six first vertical ribs are arranged between the second annular rib and the first annular rib, and six fan-shaped cavities are divided, twelve second vertical ribs are arranged between the third annular rib and the second annular rib, and twelve fan-shaped cavities are divided, eighteen third vertical ribs are arranged between the fourth annular rib and the third annular rib, and eighteen fan-shaped cavities are divided, and six of the first vertical rib, the second vertical rib and the third vertical rib are respectively on the same direct line, wherein Three straight lines divide the circle into three 120° sector-shaped areas, forming a three-way coolant flow path. The first annular rib corresponding to each 120° sector-shaped area is provided with a first through hole, and the corresponding second annular rib is provided with a second through hole. The second through hole and the first through hole are respectively connected to the two sector-shaped cavities, and a third through hole is provided on the vertical rib between the two sector-shaped cavities. The vertical ribs between the four sector-shaped cavities of the corresponding second annular rib and the third annular rib are all provided with a fourth through hole. The connecting hole on the sector-shaped cavity farthest from the second through hole is sealed with an outlet sealing plate 6, and the connecting holes on the remaining sector-shaped cavities are sealed with a cavity sealing plate 3. There are three outlet sealing plates 6 and fifteen cavity sealing plates 3 in total. The inner diameter of the first annular rib is preferably 80 mm. The inner wall of the first annular rib is in contact with the reflector core shaft support structure, so it needs to be fine-machined to ensure that the cylindricity is better than 0.005 mm. The diameters of the first through hole, the second through hole, the third through hole, and the fourth through hole are preferably 8 mm.

[0035] In the above technical solution, the inlet sealing plate 4 is preferably made of indium steel, which has a thermal expansion coefficient similar to that of silicon carbide, to ensure that the mirror structure does not generate bonding stress when the ambient temperature changes. The inlet sealing plate 4 is preferably bonded and fixed using 2216 optical sealing structural adhesive.

[0036] In the above technical solution, the cavity sealing plate 3 is preferably made of indium steel with a thermal expansion coefficient close to that of silicon carbide to ensure that the mirror structure does not generate bonding stress when the ambient temperature changes. The cavity sealing plate 3 is preferably bonded and fixed using 2216 optical sealing structural adhesive.

[0037] In the above technical solution, the outlet sealing plate 6 is made of indium steel material having a thermal expansion coefficient close to that of silicon carbide. Preferably, the outlet sealing plate 6 is fixed by bonding using 2216 optical sealing structural adhesive.

[0038] In the above technical solution, the outlet plug 2 is connected to the water cooler inlet through a hose, and the connection interface uses a standard airtight sealing ring.

[0039] In the above technical solution, the inlet plug 5 is connected to the outlet of the water cooler through a hose, and the connection interface uses a standard airtight sealing ring.

[0040] In the above technical solution, coolant 7 is preferably ethylene glycol, which has high viscosity and thermal conductivity. Coolant 7 in the water-cooling machine is filled into the central cavity of the mirror body 1-1 through the inlet connector 5. It is then divided into three streams through the three first through-holes on the first annular rib plate. These streams flow through the two fan-shaped cavities between the first and second annular rib plates (circulating through the second through-holes), then flow through the third through-holes on the second annular rib plate into the four fan-shaped cavities between the second and third annular rib plates (circulating through the fourth through-holes), and finally flow out through the outlet connector 2 and return to the water-cooling machine, thus forming a circulating cooling water flow, with each water-cooling channel being relatively independent. The high viscosity and thermal conductivity of coolant 7 removes heat absorbed by the reflective surface of the silicon carbide mirror, thereby suppressing the temperature rise of the mirror body. Coolant 7 circulates within the mirror body, and the flow rate of coolant 7 is preferably controlled at 1 to 2 L / min. The specific flow rate control depends on parameters such as the incident laser power and the laser incident time.

[0041] In the above technical solution, since the laser light output by most fiber lasers has a Gaussian intensity distribution, with high power density in the laser center and low power density in the laser outer ring, the temperature of the mirror body rises rapidly after the laser enters the reflector, significantly affecting the reflector's surface accuracy. However, the temperature rise in the outer ring of the mirror body is very low, which has little impact on the reflector's surface accuracy. In summary, the coolant 7 does not need to flow into the outermost sector of the mirror body.

[0042] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the embodiments. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A liquid-cooled silicon carbide reflector structure, characterized in that: It includes a silicon carbide matrix (1), an outlet plug (2), a cavity sealing plate (3), an inlet sealing plate (4), an inlet plug (5), an outlet sealing plate (6), and a coolant (7); The silicon carbide matrix (1) consists of a mirror body (1-1) and a back plate (1-2). The back surface of the mirror body (1-1) is a lightweight cavity structure, which is a circular ring radial structure composed of N circular ring rib plates arranged in sequence from the inside to the outside, N≥3, and there are P circular ring rib plates respectively provided with a number of through holes independently, P<N. M vertical rib plates are respectively and independently fixed between two adjacent circular ring rib plates, dividing M fan-shaped cavities respectively and independently between two adjacent circular ring rib plates, M≥3, and there are Q vertical rib plates provided with through holes, Q<M; The through holes on the circular ring rib plates and the through holes on the vertical rib plates form one or more coolant flow paths; The back plate (1-2) is hermetically fixed on the back surface of the mirror body (1-1), and a central through hole and a number of connecting holes are opened on the outer surface. The central through hole is aligned with the inner wall of the top opening of the innermost circular ring rib plate, and each fan-shaped cavity is communicated with a connecting hole; A circular ring step structure is opened on the innermost circular ring rib plate. The inlet sealing plate (4) is disc-shaped and is fitted with the circular ring step structure and is hermetically installed on the circular ring step structure to form a sealed central cavity, and the height of the top surface of the inlet sealing plate (4) is lower than the height of the top surface of the innermost circular ring rib plate. An inlet plug mounting hole is opened on the inlet sealing plate (4); The inlet plug (5) is hermetically fixed on the inlet plug mounting hole; The outlet sealing plate (6) is one or more, and is sealed on the connecting holes of the fan-shaped cavities at the end of each coolant flow path. An outlet plug mounting hole is opened on the outlet sealing plate (6); The number of the outlet plugs (2) is equal to the number of the outlet sealing plates (6), and each outlet plug (2) is installed in an outlet plug mounting hole; The connecting holes on the remaining fan-shaped cavities communicated with the through holes are all sealed with the cavity sealing plate (3); The coolant (7) enters the central cavity through the inlet plug (5), flows in the fan-shaped cavity through the through hole, and finally flows out through the outlet plug (2).

2. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The precision of the mirror body is better than 2nm, and the cylindricity of the innermost circular ring rib plate is better than 0.005mm.

3. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The lightweight cavity structure is composed of four annular ribs arranged in sequence from the inside to the outside, the innermost layer is the first annular rib, six first vertical ribs are arranged between the second annular rib and the first annular rib, and six fan-shaped cavities are divided, twelve second vertical ribs are arranged between the third annular rib and the second annular rib, and twelve fan-shaped cavities are divided, eighteen third vertical ribs are arranged between the fourth annular rib and the third annular rib, and eighteen fan-shaped cavities are divided, and six of the first vertical ribs, the second vertical ribs and the third vertical ribs are respectively on the same straight line, three of which connect the mirror body (1- 1) is divided into three 120° fan-shaped areas, a first through hole is provided on the first circular rib plate corresponding to each 120° fan-shaped area, a second through hole is provided on the corresponding second circular rib plate, and the second through hole and the first through hole are respectively connected to the two fan-shaped cavities, and a third through hole is provided on the vertical rib plate between the two fan-shaped cavities, and a fourth through hole is provided on the vertical rib plate between the four fan-shaped cavities of the corresponding second circular rib plate and the third circular rib plate, and the connection hole on the fan-shaped cavity farthest from the second through hole is sealed with an outlet sealing plate (6), and the connection holes on the remaining fan-shaped cavities are sealed with a cavity sealing plate (3).

4. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The connection holes corresponding to the outermost fan-shaped cavity are all fan-shaped, and the connection holes corresponding to the fan-shaped cavity between the innermost circular annular rib plate and the outermost fan-shaped cavity are all circular.

5. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The cavity sealing plate (3), the inlet sealing plate (4) and the outlet sealing plate (6) are all fixed by bonding.

6. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The cavity sealing plate (3), the inlet sealing plate (4) and the outlet sealing plate (6) are all made of indium steel.

7. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The inlet plug (5) is connected to the outlet of the water cooler through a hose, and the outlet plug (2) is connected to the inlet of the water cooler through a hose, and both connection interfaces use standard airtight sealing rings.

8. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The cooling liquid (7) is ethylene glycol.

9. The liquid-cooled silicon carbide reflector structure according to claim 1, characterized in that: The flow rate of the cooling liquid is 1-2 L / min.

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