Heatable radome end connecting structure

Abstract

The invention discloses a heatable radome end connecting structure, and relates to the technical field of automobile parts, the heatable radome end connecting structure comprises a mounting ring, the mounting ring is connected with a fixing ring, the middle of the mounting ring is communicated with the middle of the fixing ring, the heatable radome end connecting structure further comprises a heat conducting ring, the heat conducting ring is arranged between the mounting ring and the fixing ring, and a wave-transparent plate is fixed in the center of the heat conducting ring. The bottom end of the heat conduction ring protrudes out of the bottom face of the wave-transparent plate and the bottom face of the installation ring, and the outer wall of the heat conduction ring is wrapped with a heating belt. The heat conduction ring protruding out of the plane of the wave-transparent plate is arranged in the radome, the heating belt surrounds the outer wall of the heat conduction ring, heat generated by the heating belt is rapidly conducted to an icing layer outside a vehicle through the heat conduction ring, the part, making contact with the heat conduction ring, of the icing layer is rapidly melted, and then the ice layer covering the part of the wave-transparent plate can rapidly fall off; on the premise that the efficient wave-transparent capacity of the wave-transparent plate is guaranteed, ice and snow outside the radome are stably removed, and safe automatic driving of a vehicle is better guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile parts, in particular to a heating radar cover end connecting structure. BACKGROUND

[0002] The vehicle-mounted radar is an important sensor for realizing intelligent driving of the automobile. When the vehicle-mounted radar is installed on the automobile, a special cover shell is required to protect the radar from the influence of the external environment (such as wind sand, rain and snow, collision, etc.) while allowing effective signal penetration. The radar cover is usually required to have low loss, good weather resistance, certain strength and toughness. In some areas where severe weather conditions occur frequently, such as the cold and snowy north, the radar cover may also be equipped with a heating function to prevent ice and snow from covering and affecting the normal operation of the radar.

[0003] A heating radar cover end connecting structure is disclosed in Chinese Patent No. CN110562165B, which comprises a diaphragm, a heating wire, and a front cover plate. The heating wire is printed on the diaphragm according to a set layout to form a heating diaphragm piece. The heating diaphragm piece includes a main body part and a bending area part. The bending area part protrudes from the edge of the main body part. The main body part is arranged on the front surface of the front cover plate. The rear end of the front cover plate has a bending assembly part at the joint with the bending area part. The bending assembly part is integrally injection molded with the front cover plate. The bending area part is connected and assembled on the bending assembly part after being bent tightly. The bending assembly part is provided with a conductive sheet and a connector.

[0004] In view of the above related technology, since the existing radar cover materials (such as glass steel) mostly have poor heat conduction efficiency, the heating wire arranged between the front cover and the rear cover often needs to have a high density to uniformly transmit heat and achieve melting of ice and snow outside the radar cover. Moreover, the high-density heating wire is prone to deformation of the radar cover due to sharp temperature changes during rapid temperature rise of the radar cover, which may affect the farthest distance of radar target detection and the angle measurement accuracy. In summary, the existing heating radar cover end connecting structure is prone to affecting the working performance of the radar when melting ice and snow. SUMMARY

[0005] Therefore, the present application aims to provide a heating radar cover end connecting structure to solve the technical problem that the existing heating radar cover end connecting structure is prone to affecting the working performance of the radar when melting ice and snow.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution: a heating radar cover end connecting structure, comprising a mounting ring, the mounting ring being connected with a fixing ring, the center of the mounting ring and the fixing ring being penetrated, further comprising a heat conduction ring, the heat conduction ring being arranged between the mounting ring and the fixing ring, and a wave-transparent plate being fixed at the center of the heat conduction ring, the bottom end of the heat conduction ring protruding from the bottom surface of the wave-transparent plate and the mounting ring, and a heating tape being wrapped around the outer wall of the heat conduction ring.

[0007] By adopting the technical scheme, the heat generated by the heating belt is quickly conducted to the ice layer outside the vehicle through the heat-conducting ring, the part of the ice layer in contact with the heat-conducting ring is quickly melted, and then the ice layer covering the part of the wave-transparent plate can be quickly removed, the ice and snow outside the radar cover are stably removed under the premise of guaranteeing the efficient wave-transparent capability of the wave-transparent plate, and the safety automatic driving of the vehicle is better guaranteed.

[0008] The application further provides that a first prism is arranged between the outer edge of the top end of the heat-conducting ring and the inner wall of the mounting ring, and the inner ring of the first prism is provided with a second prism, and the radiation emitted by the heating belt can be irradiated on the top surface of the wave-transparent plate after being refracted by the first prism and the second prism.

[0009] Preferably, the inner surface of the wave-transparent plate is uniformly heated by the reflection of the prism assembly.

[0010] The application further provides that the inner wall of the mounting ring is provided with a first bearing table, and the edge of the top end of the heat-conducting ring is provided with a second bearing table, the bottom surface of the first prism is clamped between the first bearing table and the second bearing table, the bottom surface of the second prism is in contact with the top surface of the heat-conducting ring and the wave-transparent plate, and the bottom surface of the fixing ring is in contact with the top end of the first prism and the second prism at the same time.

[0011] Preferably, the second prism also serves as a support for the wave-transparent plate.

[0012] The application further provides that the cross section of the first prism is a right-angled triangle, one of the right-angled sides faces downward, and the other right-angled side faces the second prism, the cross section of the second prism is an isosceles triangle, and the side of the second prism that is not equal to the other two sides is in contact with the heat-conducting ring and the wave-transparent plate.

[0013] Preferably, the infrared radiation generated by the heating belt can be smoothly refracted to the surface of the wave-transparent plate.

[0014] The application further provides that the fixing ring is internally provided with heat insulation cotton, and the diameter of the heat insulation cotton is greater than the diameter of the central through port of the fixing ring.

[0015] Preferably, the heat insulation cotton can protect the radar and improve the temperature rising rate of the wave-transparent plate at the same time.

[0016] The application further provides that the inner edge of the bottom end of the heat-conducting ring is provided with a limiting table, the wave-transparent plate cannot move away from the fixing ring due to the limiting of the limiting table, the heat-conducting ring is provided with a water-permeable port for water permeation at the edge of the limiting table, and the water-permeable port of the heat-conducting ring is flush with the bottom surface of the wave-transparent plate.

[0017] Preferably, the water outlet drains the water between the surface of the wave-transparent plate and the ice layer, which is beneficial for the rapid shedding of the ice layer on the surface of the wave-transparent plate.

[0018] The present invention is further configured such that a reflective layer is provided on the inner wall of the mounting ring below the first prism.

[0019] Preferably, the reflective layer can further enhance the light intensity illuminating the surface of the wave-transparent plate.

[0020] The present invention is further configured such that a conductive interface passing upward through a heat-conducting ring is fixedly connected to the edge of the heating tape, and the fixing ring and the heat insulation cotton are respectively provided with a first perforation and a second perforation facing the conductive interface of the heating tape.

[0021] Preferably, the heating element is powered by passing a wire through the first and second perforations.

[0022] The present invention is further configured such that the diameter of the inner ring of the heat-conducting ring is equal to the diameter of the inner ring of the fixed ring.

[0023] Preferably, the size of the radome should not be too large, as this would affect its aesthetics.

[0024] The present invention is further configured such that the top of the inner wall of the mounting ring is provided with an internal thread, and the top of the outer wall of the fixing ring is provided with an external thread for engaging with the internal thread of the mounting ring. After the fixing ring and the mounting ring are threadedly connected, the bottom end of the fixing ring presses against the first prism and the second prism, and the bottom end of the second prism presses against the heat-conducting ring and the wave-transparent plate.

[0025] Preferably, a threaded connection is used to conveniently connect the mounting ring and the retaining ring.

[0026] In summary, the present invention has the following main beneficial effects: This invention features a heat-conducting ring protruding from the radar dome inside the radome, with a heating band surrounding the outer wall of the ring. The heat generated by the heating band is rapidly conducted to the ice layer outside the vehicle, causing the part of the ice layer in contact with the heat-conducting ring to melt quickly. This allows the ice layer covering the radar dome to fall off quickly, ensuring the efficient radar dome transmission while achieving stable removal of ice and snow from the outside of the radome, thus better guaranteeing the safe autonomous driving of the vehicle.

[0027] This invention utilizes a prism refraction structure between the mounting ring and the fixing ring to reflect the heat radiation generated by the side of the heating tape away from the heat-conducting ring to the inner surface of the transparent plate. This effectively utilizes the heat generated by the heating tape, shortens the heat transfer path, and achieves uniform heat transfer to the central position of the transparent plate even when the thermal conductivity of the transparent plate is poor, thereby maintaining the temperature of the transparent plate during vehicle operation. The application opens multiple water permeable openings on the edge of the heat conduction ring, when the part of the heat conduction ring protruding from the plane of the wave-transparent plate melts the ice layer, with the gradual warming of the wave-transparent plate, there is water between the wave-transparent plate and the ice layer after melting, the water permeable opening plays a role in guiding the water generated by melting, effectively preventing the water between the un-melted ice layer and the wave-transparent plate from falling smoothly, further improving the efficiency of ice and snow removal on the outer surface of the wave-transparent plate; The application positions the wave-transparent plate through the cooperation of the fixed ring, the prism structure and the heat conduction ring, effectively preventing the wave-transparent plate from shaking or angle deviation during vehicle driving, and the homogeneous wave-transparent plate is not easy to interfere with the normal use of the radar, thereby effectively improving the accuracy of the radar in use, further improving the safety of intelligent driving of the vehicle; The application sets up the heat insulation cotton in the fixed ring to isolate the heat reflected to the surface of the wave-transparent plate by the prism assembly, effectively avoiding heat leakage, further improving the warming rate of the wave-transparent plate, and the heat insulation cotton can also effectively prevent the surface temperature of the wave-transparent plate from rising too high to affect the normal work of the radar, and plays a role in separating the radar and the wave-transparent plate. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a perspective view of the application; Figure 2 It is another perspective view of the application; Figure 3 It is a sectional state perspective view of the application; Figure 4 It is a sectional state perspective view of the application; Figure 3 It is an enlarged view of A in the application; Figure 5 It is an enlarged view of B in the application; Figure 3 Figure 6 It is another perspective view of the application; Figure 7 It is a sectional state front view of the application; Figure 8 It is a radiation refraction path schematic view of the application; Figure 9 It is an exploded view of the application; Figure 10 It is a perspective view of the heat conduction ring and the heating band of the application.

[0029] Explanation of reference signs: 1, mounting ring; 101, first bearing table; 2, fixed ring; 201, first through hole; 3, heat conduction ring; 301, limiting table; 302, water permeable opening; 303, second bearing table; 4, heating band; 5, wave-transparent plate; 6, first prism; 7, second prism; 8, heat insulation cotton; 801, second through hole. DETAILED DESCRIPTION​

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and are used only for explaining the present application, and cannot be understood as a limitation of the present application.

[0031] The embodiments of the present application will be described below according to the overall structure of the present application. Embodiment one

[0032] A kind of heating radome end connection structure, please refer to Figures 1-10 , including mounting ring 1, mounting ring 1 is connected with fixed ring 2, the middle part of mounting ring 1 and fixed ring 2 is through, further, in other embodiments, in order to adapt to the size and shape of radar, mounting ring 1 and fixed ring 2 are not necessarily circular ring, can also use rectangular ring structure and other types, the present application does not limit the shape and size of mounting ring 1 and fixed ring 2, and in the present embodiment, mounting ring 1 and fixed ring 2 are specifically circular ring structure, the through hole through the center is also circular ring.

[0033] It also includes heat conduction ring 3, heat conduction ring 3 is arranged between mounting ring 1 and fixed ring 2, and the center is fixed with wave-transparent plate 5, the bottom end of heat conduction ring 3 protrudes wave-transparent plate 5 and the bottom surface of mounting ring 1, the outer wall of heat conduction ring 3 is wrapped with heating band 4, specifically, heat conduction ring 3 is made of material with strong heat conduction rate, specifically can use but not limited to copper, aluminum, in the present application, heat conduction ring 3 is specifically made of copper, heating band 4 is specifically electric heating wire wound on the outer wall of heat conduction ring 3, in order to further improve the heat transfer efficiency of heat conduction ring 3 and the protection performance of radome, the area where the inner wall of heat conduction ring 3 contacts wave-transparent plate 5 is coated with heat-conducting silicone grease.

[0034] In the above embodiment, specifically please refer to Figures 3-9 , the outer edge of the top end of heat conduction ring 3 is provided between the inner wall of mounting ring 1, the inner circle of first prism 6 is provided with second prism 7, the diameter of second prism 7 is smaller than that of first prism 6, and second prism 7 is coaxially arranged with first prism 6, the radiation emitted by heating band 4 can be irradiated on the top surface of wave-transparent plate 5 after refraction by first prism 6 and second prism 7, the inner surface of wave-transparent plate 5 is uniformly heated by the reflection of prism assembly, the heat generated by heating band 4 is transferred from the edge of wave-transparent plate 5 to the center of wave-transparent plate 5 after conduction by heat conduction ring 3, since the heat conduction capacity of wave-transparent plate 5 is poor, the combination of heat conduction by heat conduction ring 3 and reflection of radiation by prism can further accelerate the heating efficiency of wave-transparent plate 5, and since no heating wire is arranged inside wave-transparent plate 5, wave-transparent plate 5 is not easy to deform greatly when the radome is heated to melt ice, thereby effectively controlling the influence of temperature change of radome on radar waves.

[0035] Specifically, the cross section of the first prism 6 is a right triangle, and one of the right angles faces downward and the other right angle faces the second prism 7. The cross section of the second prism 7 is an isosceles triangle, and the side of the second prism 7 that is not equal to the other two sides contacts the heat-conducting ring 3 and the wave-transparent plate 5. The infrared radiation generated by the heat-generating band 4 is refracted by the first prism 6 and then irradiates the side of the second prism 7. The infrared radiation passes through the second prism 7 and then irradiates the surface of the wave-transparent plate 5 obliquely downward. Most of the light passing through the second prism 7 irradiates the wave-transparent plate 5 near the middle. In combination with the heat conducted by the heat-conducting ring 3 contacting the edge of the wave-transparent plate 5, the temperature of the wave-transparent plate 5 is quickly raised, so that the infrared radiation generated by the heat-generating band 4 can be smoothly refracted to the surface of the wave-transparent plate 5. Further, the inner wall of the mounting ring 1 is provided with a reflective layer below the first prism 6. The reflective layer can further improve the light intensity irradiating the surface of the wave-transparent plate 5, and also can avoid the heat from spreading to the mounting ring 1.

[0036] Further, the inner wall of the mounting ring 1 is provided with a first bearing table 101, and the edge of the top end of the heat-conducting ring 3 is provided with a second bearing table 303. The bottom surface of the first prism 6 is clamped between the first bearing table 101 and the second bearing table 303. The bottom surface of the second prism 7 contacts the top surface of the heat-conducting ring 3 and the wave-transparent plate 5. The bottom surface of the fixing ring 2 simultaneously contacts the top end of the first prism 6 and the second prism 7. The second prism 7 also supports the wave-transparent plate 5. Specifically, the bottom end of the first prism 6 contacts the first bearing table 101 and the second bearing table 303, and the top end contacts the bottom surface of the fixing ring 2. A step is arranged between the bottom of the heat-conducting ring 3 and the mounting ring 1, so that the fixing ring 2 can position the heat-conducting ring 3 after installation. Similarly, the top end of the second prism 7 contacts the bottom surface of the fixing ring 2, and the bottom end simultaneously contacts the heat-conducting ring 3 and the wave-transparent plate 5. The heat-conducting ring 3 is limited in movement, and the wave-transparent plate 5 is also limited in movement.

[0037] In the above embodiment, specifically, please refer to Figures 3-6 The fixing ring 2 is provided with the heat insulation cotton 8. Specifically, the heat insulation cotton 8 in this embodiment is aerogel heat insulation cotton. The thickness of the heat insulation cotton 8 is not more than 1 mm. The diameter of the heat insulation cotton 8 is greater than the diameter of the central through port of the fixing ring 2, so that the through port of the middle part of the fixing ring 2 can be completely closed. The heat insulation cotton 8 can protect the radar and improve the temperature rising rate of the wave-transparent plate 5, so that the heat accumulation of the wave-transparent plate 5 after the radar is heated is avoided.

[0038] In the above embodiment, specifically, please refer to Figures 3-9In the embodiment, the mounting ring 1 and the fixing ring 2 are connected by screwing, specifically, the top of the inner wall of the mounting ring 1 is provided with an internal thread, the top of the outer wall of the fixing ring 2 is provided with an external thread matched with the internal thread of the mounting ring 1, after the fixing ring 2 is screwed with the mounting ring 1, the bottom end of the fixing ring 2 presses the first prism 6 and the second prism 7, the bottom end of the second prism 7 presses the heat-conducting ring 3 and the wave-transparent plate 5, the mounting ring 1 and the fixing ring 2 are conveniently connected by screwing, and in other undisclosed embodiments, the mounting ring 1 and the fixing ring 2 can also be connected by gluing, clamping and the like. Embodiment two

[0039] A heated radar cover end connecting structure, please refer to Figures 1-10 On the basis of the first embodiment, different from the first embodiment is that the inner edge of the bottom end of the heat-conducting ring 3 is provided with a limiting table 301, the wave-transparent plate 5 cannot move away from the fixing ring 2 due to the limiting of the limiting table 301, and the heat-conducting ring 3 is provided with water-permeable openings 302 at the edge of the limiting table 301 for water permeation.

[0040] Specifically, since the end of the heat-conducting ring 3 exceeds the surface of the wave-transparent plate 5, after the ice layer around the heat-conducting ring 3 melts, a small water pool can be formed in the inner circle of the heat-conducting ring 3, when the radar of the vehicle is arranged at a certain elevation angle, the sheet ice layer on the surface of the wave-transparent plate 5 can not be smoothly removed from the middle of the heat-conducting ring 3, but in the embodiment, the water melted from the ice layer in the inner circle of the heat-conducting ring 3 can be smoothly discharged through the water-permeable openings 302, the circular ice pieces on the surface of the wave-transparent plate 5 directly contact with the surface of the wave-transparent plate 5, and due to the shaking of the vehicle, the ice pieces can be more easily removed, the water-permeable openings 302 of the heat-conducting ring 3 are flush with the bottom surface of the wave-transparent plate 5, the water-permeable openings 302 discharge the water between the surface of the wave-transparent plate 5 and the ice layer, and this is beneficial to the rapid removal of the ice layer on the surface of the wave-transparent plate 5. Embodiment three

[0041] A heated radar cover end connecting structure, please refer to Figures 1-10 On the basis of the second embodiment, different from the second embodiment is that the edge of the heat-generating belt 4 is fixedly connected with a conductive interface penetrating the heat-conducting ring 3 upwards, the fixing ring 2 and the heat insulation cotton 8 are respectively provided with a first perforation 201 and a second perforation 801 facing the conductive interface of the heat-generating belt 4, the heat-generating belt 4 is powered by the conductive interface through the first perforation 201 and the second perforation 801, and the heat insulation cotton 8 is connected with the fixing ring 2 by gluing, the second perforation 801 of the heat insulation cotton 8 is aligned with the first perforation 201 of the fixing ring 2 when connected, and the first perforation 201 is aligned with the conductive interface of the heat-generating belt 4 after the fixing ring 2 is fixedly connected with the mounting ring 1.

[0042] Further, the diameter of the inner ring of the heat conduction ring 3 is equal to the diameter of the inner ring of the fixed ring 2, which avoids the radar cover being too large to affect the appearance while ensuring that the radar wave can normally pass through the wave-transparent plate 5.

[0043] In the case of rain, snow and low temperature weather, when the vehicle starts, the heating band 4 is powered and heated at the same time, the heat generated by the heating band 4 is efficiently conducted to the ice layer outside the radar cover through the heat conduction ring 3, and the ice layer melts rapidly to form a ring-shaped gap with the heat conduction ring 3 as the boundary, the wave-transparent plate 5 slowly heats up under the condition of the refracted light of the prism assembly, and the ice layer contacting the outer surface of the wave-transparent plate 5 melts first, the water generated by the melting of the ice layer on the surface of the wave-transparent plate 5 is discharged along the water-permeable port 302, and the circular ice pieces on the surface of the wave-transparent plate 5 can be easily blown off by the airflow when the vehicle starts to move, during the vehicle driving process, the heating band 4 continuously generates heat, so that the temperature of the wave-transparent plate 5 is always higher than the ambient temperature, so that the snowflakes falling on the surface of the wave-transparent plate 5 cannot be attached, effectively avoiding the radar cover surface icing or being blocked by snowflakes, and also greatly improving the removal efficiency of the ice layer outside the radar cover after the vehicle starts, and the homogeneous wave-transparent plate 5 is also less likely to affect the radar wave.

[0044] Although the embodiments of the present application have been shown and described, the specific embodiments are only an explanation of the present application, and are not a limitation of the application, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner, and those skilled in the art can make modifications, replacements and variations of the embodiments without creative contribution after reading the specification, as long as they are within the scope of the claims of the present application.

Claims

1. A heatable radar dome end connection structure, characterized in that, include: Mounting ring (1), the mounting ring (1) is connected to a fixing ring (2), and the middle parts of the mounting ring (1) and the fixing ring (2) are connected; A heat-conducting ring (3) is disposed between the mounting ring (1) and the fixing ring (2), and a wave-transparent plate (5) is fixed in the center. The bottom end of the heat-conducting ring (3) protrudes from the bottom surface of the wave-transparent plate (5) and the mounting ring (1). The outer wall of the heat-conducting ring (3) is wrapped with a heat-generating tube (4).

2. The heatable radome end connection structure according to claim 1, characterized in that: A first prism (6) is provided between the outer edge of the top of the heat-conducting ring (3) and the inner wall of the mounting ring (1). A second prism (7) is provided in the inner ring of the first prism (6). The radiation emitted by the heat-generating heat (4) can irradiate the top surface of the wave-transparent plate (5) after being refracted by the first prism (6) and the second prism (7).

3. The end connection structure of the heatable radome according to claim 2, characterized in that: The inner wall of the mounting ring (1) is provided with a first support platform (101), and the edge of the top of the heat-conducting ring (3) is provided with a second support platform (303). The bottom surface of the first prism (6) is engaged between the first support platform (101) and the second support platform (303). The bottom surface of the second prism (7) is in contact with the top surface of the heat-conducting ring (3) and the wave-transparent plate (5). The bottom surface of the fixing ring (2) is in contact with the top of the first prism (6) and the second prism (7).

4. The end connection structure of the heatable radome according to claim 3, characterized in that: The first prism (6) has a right-angled triangle cross section, with one right-angled side facing downwards and the other right-angled side facing the second prism (7). The second prism (7) has an isosceles triangle cross section. The side of the second prism (7) cross section that is not equal to the other two sides contacts the heat-conducting ring (3) and the wave-transparent plate (5).

5. The heatable radome end connection structure according to claim 4, characterized in that: The fixing ring (2) is equipped with heat insulation cotton (8), and the diameter of the heat insulation cotton (8) is larger than the diameter of the central opening of the fixing ring (2).

6. The end connection structure of the heatable radome according to claim 1, characterized in that: The inner edge of the bottom of the heat-conducting ring (3) is provided with a limiting platform (301). The wave-transparent plate (5) is limited by the limiting platform (301) and cannot move away from the fixed ring (2). The heat-conducting ring (3) is provided with water inlets (302) at intervals on the edge of the limiting platform (301). The water inlets (302) of the heat-conducting ring (3) are flush with the bottom surface of the wave-transparent plate (5).

7. The heatable radome end connection structure according to claim 5, characterized in that: The inner wall of the mounting ring (1) is provided with a reflective layer below the first prism (6).

8. The heatable radome end connection structure according to claim 5, characterized in that: The edge of the heating tape (4) is fixedly connected to a conductive interface that passes through the heat-conducting ring (3) upwards. The fixing ring (2) and the heat insulation cotton (8) are respectively provided with a first perforation (201) and a second perforation (801) facing the conductive interface of the heating tape (4).

9. The end connection structure of the heatable radome according to claim 6, characterized in that: The diameter of the inner ring of the heat-conducting ring (3) is equal to the diameter of the inner ring of the fixed ring (2).

10. The heatable radar dome end connection structure according to claim 5, characterized in that: The top of the inner wall of the mounting ring (1) is provided with an internal thread, and the top of the outer wall of the fixing ring (2) is provided with an external thread for cooperating with the internal thread of the mounting ring (1). After the fixing ring (2) is threadedly connected to the mounting ring (1), the bottom end of the fixing ring (2) presses against the first prism (6) and the second prism (7), and the bottom end of the second prism (7) presses against the heat-conducting ring (3) and the wave-transparent plate (5).

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