Optical module and lamp

Abstract

The application provides an optical module and a lamp, the optical module is applied to the lamp, and comprises an optical part, the optical part comprises a plurality of microstructures arranged along a first direction, the microstructure comprises a first surface and a second surface arranged at an angle, the first surface faces away from the first direction, the second surface faces the first direction, and a warning coating is arranged on the first surface or the second surface; and a connecting part connected with the optical part, the connecting part is used for mounting the optical module on a shell of the lamp. Compared with the prior art, the optical module of the application can timely remind the driver of reverse driving without affecting the illumination.

Description

Technical Field

[0001] This invention relates to the field of lighting device technology, and more particularly to an optical module and a lamp. Background Technology

[0002] Compared to ordinary roads, highway tunnels are enclosed spaces. Once an accident occurs, not only are rescue and evacuation difficult, but the consequences are also more serious, making traffic safety issues increasingly prominent.

[0003] Ordinary lights only provide illumination and lack warning and guidance functions. Especially when drivers are unfamiliar with the road, they are prone to driving against the flow of traffic in tunnels. Driving against the flow of traffic is a serious violation of traffic laws, which can cause traffic congestion and reduce road capacity, or even serious accidents resulting in vehicle damage and fatalities. Therefore, how to provide drivers with a warning of driving against the flow of traffic without affecting the illumination of the lights is a pressing technical problem that needs to be solved.

[0004] In view of this, it is indeed necessary to provide an optical module and a lamp to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an optical module for use in lighting fixtures, which can use the illumination of the lighting fixtures to provide a reminder of reverse driving.

[0006] To achieve the above objectives, the present invention provides an optical module for use in a lamp, comprising an optical part, the optical part including a plurality of microstructures arranged along a first direction, the microstructures including a first surface and a second surface arranged at an angle, the first surface facing away from the first direction, the second surface facing the first direction, and a warning coating provided on the first surface or the second surface; and a connecting part connecting the optical part, the connecting part being used to install the optical module onto the housing of the lamp.

[0007] As a further improvement of the present invention, both the first surface and the second surface are provided with a coating, one of the first surface and the second surface is provided with a warning coating, and the coating on the other of the first surface and the second surface is a different color from the warning coating.

[0008] As a further improvement of the invention, the color of the coating on the other of the first and second surfaces is the same as the color of the housing of the lamp.

[0009] As a further improvement of the present invention, the connecting portion extends in a direction parallel to the first direction, and the first surface and the connecting portion have a first included angle, the second surface and the connecting portion have a second included angle, and the sum of the first included angle and the second included angle is an obtuse angle.

[0010] As a further improvement of the present invention, there is a third included angle between the first surface and the second surface, wherein the third included angle is less than 80° or equal to 80°.

[0011] As a further improvement of the present invention, the cross-section of the microstructure is triangular.

[0012] Another object of the present invention is to provide a lamp having the above-described optical module.

[0013] To achieve the above objectives, the present invention provides a lamp, including a housing and a mask, wherein a receiving space is formed between the housing and the mask, and the aforementioned optical module is disposed within the receiving space; a light source module is disposed within the receiving space, and light emitted by the light source module at least partially illuminates the optical module.

[0014] As a further improvement of the present invention, two light source modules are provided, which are disposed on both sides of the housing, and the optical module is disposed between the two light source modules. Furthermore, the light source modules are tilted toward the optical part on the optical module, and the optical part is toward the mask.

[0015] As a further improvement of the present invention, a reflective portion is formed on the side of the housing facing the receiving space, and the light emitted by the light source module is reflected by the reflective portion and then emitted through the mask.

[0016] As a further improvement of the present invention, the light source module includes a light source substrate and a plurality of light sources disposed on the light source substrate.

[0017] As a further improvement of the present invention, the housing includes a mask receiving portion for accommodating the mask, the mask receiving portion being disposed below the light source module, and including a first connecting portion located at the bottom of the housing and a second connecting portion fixedly connected to the first connecting portion.

[0018] As a further improvement of the present invention, the first joint portion includes a second slot facing the receiving space and a side joint portion facing away from the receiving space. The second joint portion includes a first sidewall and a second sidewall connected together. The second sidewall extends from the bottom of the first sidewall outward from the side joint portion and toward the receiving space to at least partially cover the second slot.

[0019] The beneficial effects of the present invention are as follows: Compared with the prior art, the optical module of the present invention arranges multiple microstructures on the optical part along a first direction, and the microstructures include a first surface and a second surface with an included angle, wherein the first surface faces away from the first direction and the second surface faces the first direction, and a warning coating is provided on the first surface or the second surface, so that when passing the optical module along the first direction, the first surface is visible and the second surface is not visible; when passing the optical module along the opposite direction from the first direction, the first surface is not visible and the second surface is visible. Thus, when the driver is driving in the correct direction, the warning coating is not visible, but when driving in the opposite direction, the warning coating is visible. Therefore, the driver can be promptly reminded of the driver driving in the opposite direction without affecting the lighting, thereby improving driving safety. Attached Figure Description

[0020] Figure 1 This is a perspective view of a lamp according to a preferred embodiment of the present invention;

[0021] Figure 2 yes Figure 1 Exploded view of the structure of the lamp;

[0022] Figure 3 for Figure 1 A sectional view of the central lighting fixture;

[0023] Figure 4 yes Figure 1 A three-dimensional view of part of the housing structure of the lamp;

[0024] Figure 5 yes Figure 1 A perspective view of a portion of the structure of the second joint of the central lighting fixture;

[0025] Figure 6 This is a perspective view of an optical module according to a preferred embodiment of the present invention;

[0026] Figure 7 for Figure 6 A magnified view of the optical module in the middle;

[0027] Figure 8 for Figure 1 Light path diagram of the lamp.

[0028] 100 - Lighting fixtures;

[0029] 10-Housing, 11-Arc-shaped sidewall, 12-Mounting part, 13-Light source housing part, 131-First slot, 132-First limiting part, 133-Second limiting part, 14-Optical housing part, 141-Receiving cavity, 15-Reflecting part, 16-Mask housing part, 161-First connecting part, 1611-Second slot, 1612-Side connecting part, 1613-Limiting plate, 162-Second connecting part, 1621-First sidewall, 1622-Second sidewall, 1623-Inclined guide surface, 1624-Matching part, 17-Connecting part;

[0030] 20-face mask;

[0031] 30 - Containment space;

[0032] 40 - Light source module, 41 - Light source substrate, 42 - Light source;

[0033] 50 - Optical module, 51 - Connector, 52 - Optical part, 521 - Microstructure, 5211 - First surface, 5212 - Second surface;

[0034] 60 - End cap, 61 - Main body, 62 - Edge banding;

[0035] a1 - the first included angle, a2 - the second included angle, a3 - the third included angle. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0038] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0039] Please see Figure 1-8The image shows a preferred embodiment of a lamp 100 according to the present invention. This lamp 100 is used in environments requiring oncoming traffic warnings. Preferably, in this embodiment, the lamp 100 is a tunnel light, used to warn vehicles traveling in tunnels, providing a warning to drivers without affecting illumination, and preventing oncoming traffic. In other embodiments, the lamp 100 can also be other road lighting related lamps 100, such as streetlights or industrial / mining lights, etc., required in environments requiring oncoming traffic warnings.

[0040] In this embodiment, the lamp 100 has an elongated structure, including a housing 10 and a faceplate 20, with a receiving space 30 formed between the housing 10 and the faceplate 20. The lamp 100 also includes an optical module 50 and a light source module 40, which are disposed within the receiving space 30. Light emitted by the light source module 40 at least partially illuminates the optical module 50 and is reflected by the optical module 50 before exiting from the faceplate 20.

[0041] The housing 10 has an arc-shaped structure with two arc-shaped sidewalls 11 along its long side, which is parallel to the length direction of the tunnel. The housing 10 includes a mounting part 12 for fixing and connecting with the tunnel, a mask housing part 16 for housing the mask 20, a light source housing part 13 for housing the light source module 40, an optical housing part 14 for housing the optical module 50, and a reflective part 15 for reflecting the light emitted by the light source module 40.

[0042] Furthermore, the inner surface of the housing 10 facing the receiving space 30 is coated with a reflective material (such as a white high-reflective material) to form a reflective part 15. When the light emitted by the light source module 40 shines on the inner surface of the housing 10, the reflective part 15 is used to reflect the light and emit it through the mask 20.

[0043] In this embodiment, the mounting part 12 is disposed at the top of the housing 10 and includes two symmetrically arranged sliding grooves, which are respectively disposed on both sides of the optical receiving part 14 for connecting with the tunnel. In other embodiments, the mounting part 12 may also have other structures, which are not limited by the present invention.

[0044] The top of the housing 10 is also provided with an optical receiving part 14, which is disposed opposite to the mounting part 12 and located between two slides for receiving the optical module 50. The optical receiving part 14 has a receiving cavity 141 extending in the tunnel direction, which has an opening facing the mask 20.

[0045] An optical module 50 is disposed within the optical housing 14, including a connecting portion 51 and an optical section 52 connected to the connecting portion 51. The connecting portion 51 is used to mount the optical module 50 within the housing 10 of the lamp 100. The optical section 52 includes a plurality of microstructures 521 arranged along a first direction. Each microstructure 521 includes a first surface 5211 and a second surface 5212 arranged at an angle, wherein the first surface 5211 faces away from the first direction, and the second surface 5212 faces the first direction, and a warning coating is provided on either the first surface 5211 or the second surface 5212. This configuration ensures that when the driver passes the optical module 50 in the first direction, the first surface 5211 of the microstructure 521 is visible, while the second surface 5212 is not. When the driver passes the optical module 50 in the opposite direction, the first surface 5211 is not visible, while the second surface 5212 is visible. Thus, when the driver is driving in the correct direction, the warning coating is not visible, but when driving in the opposite direction, the warning coating is visible. This allows the driver to be promptly alerted to driving in the opposite direction without affecting the lighting, thereby improving driving safety.

[0046] In this embodiment, the connecting part 51 has a T-shaped structure, which passes through the opening of the receiving cavity 141 and is assembled into the receiving cavity 141 of the housing 10 to fix the optical module 50 onto the housing 10 of the lamp 100. The optical part 52 is disposed below the connecting part 51 and outside the opening. The optical part 52 has a plurality of microstructures 521 arranged in parallel along a first direction. The microstructures 521 are serrated, that is, the cross-section of the microstructures 521 is triangular. Each microstructure 521 includes a first surface 5211 and a second surface 5212 arranged at an included angle. When the driver passes the optical module 50 in a first direction, the first surface 5211 is visible while the second surface 5212 is not visible. When the driver passes the optical module 50 in a second direction opposite to the first direction, the second surface 5212 is visible while the first surface 5211 is visible. One of the first surface 5211 and the second surface 5212 is provided with a warning coating, so that the driver cannot see the warning coating when driving in the correct direction, but can see the warning coating when driving in the opposite direction, so as to remind the driver in time.

[0047] Furthermore, both the first surface 5211 and the second surface 5212 are provided with a reflective coating, which makes the optical part 52 opaque. One of the first surface 5211 and the second surface 5212 has a warning coating, and the color of the coating on the other surface is different from the color of the warning coating. That is, the coating on the first surface 5211 is a different color from the coating on the second surface 5212. Preferably, the color of the coating on the other surface is the same as the color of the housing 10 of the lamp 100, so as to avoid attracting the driver's attention and causing distraction when the driver is driving.

[0048] Please see Figure 3 and Figure 5 As shown, the definition Figure 3 and Figure 5 The first direction, from front to back, is the normal driving direction. The first surface 5211 faces forward (i.e., away from the first direction), and the second surface faces backward (i.e., towards the first direction). The first surface 5211 is coated with a high-reflective white coating of the same color and properties as the reflective part 15, while the second surface 5212 is coated with a different color, a red coating for warning purposes. When a car travels in the tunnel in the first direction (the normal driving direction), only the first surface 5211 is visible, and the second surface 5212 is not. This does not affect the tunnel's lighting brightness and does not attract the driver's attention, thus preventing driver distraction. When a car travels in the tunnel in the opposite direction (the reverse driving direction), only the second surface 5212 is visible, and the first surface 5211 is not. Without affecting the tunnel's lighting, the red warning surface 5212 provides timely warning of reverse driving to the driver, preventing the driver from failing to notice the intersection sign and realize the vehicle is traveling in the wrong direction while driving at high speed. Since the optical module 50 extends along the length of the tunnel, the microstructures 521 are also arranged side-by-side along the length. This provides the driver with a continuous and conspicuous warning of wrong-way driving, preventing vehicles from entering the tunnel in the wrong direction or providing a continuous warning to vehicles driving in the wrong direction. Of course, in other embodiments, the optical module 50 may be placed only at a distance between the entrance and exit sections of the tunnel.

[0049] Furthermore, the connecting portion 51 extends in a direction parallel to the first direction, and a first included angle α1 is formed between the first surface 5211 and the connecting portion 51, and a second included angle α2 is formed between the second surface 5212 and the connecting portion 51, wherein the sum of the first included angle α1 and the second included angle α2 is an obtuse angle. That is, a third included angle α3 is formed between the first surface 5211 and the second surface 5212, and the third included angle α3 is an acute angle. Furthermore, the third included angle α3 is less than or equal to 80°. In this embodiment, the third included angle α3 is 60°.

[0050] Since the upper visual field of the human eye is 50°, that is, the angle between the first surface 5211 and the horizontal direction of the lamp 100 is 50°, and the angle between the second surface 5212 and the horizontal direction of the lamp 100 is also 50°. In other words, the first angle a1 and the second angle a2 are both 50°. According to the triangle angle sum theorem, the third angle a3 is less than or equal to 80°.

[0051] Under normal circumstances, during driving, the driver's upper visual field is around 60°. When the angle between the driver's eye and the horizontal direction of the lamp 100 is greater than 60°, the first surface 5211 or the second surface 5212 of the microstructure 521 will be out of sight. At this time, the microstructure 521 on the optical part 52 appears monochromatic to the driver. When the vehicle is traveling forward (first direction), the lamp 100 only serves the purpose of illumination. Because the coating on the first surface 5211 of the optical part 52 is the same as or similar to the coating on the reflector 15 after reflecting the incident light from the light source module 40, it will not be particularly visible on the mask 20. When the vehicle is traveling in the opposite direction (second direction), the lamp 100 will display a warning line on the mask 20 while illuminating. That is, what the driver sees is the reflection of the incident light from the light source module 40 on the mask 20 after the second surface 5212 of the optical part 52 reflects the light. The color of this warning line can be determined according to the coating color of the second surface 5212 of the optical part 52. In a preferred embodiment of the present invention, the warning strip is red.

[0052] In this embodiment, two light source receiving portions 13 are provided, symmetrically arranged on both sides of the housing 10 and both positioned above the mask receiving portion 16, for receiving the light source module 40. Each light source receiving portion 13 includes a first slot 131 extending along the long side of the housing 10, and a first limiting portion 132 and a second limiting portion 133 on both sides of the first slot 131. The light source module 40 is limited and positioned within the first slot 131 by the first limiting portion 132 and the second limiting portion 133.

[0053] A first slot 131 extends obliquely from the arcuate sidewall 11 of the housing 10 toward the receiving space 30, and the opening of the first slot 131 faces the receiving space 30 of the housing 10. A first limiting portion 132 extends obliquely from the end of the first slot 131 away from the arcuate sidewall 11 toward the mounting portion 12 and is bent toward the second limiting portion 133. A second limiting portion 133 extends obliquely from the inner surface of the arcuate sidewall 11 toward the first limiting portion 132 to facilitate the mounting of the light source module 40.

[0054] Two light source modules 40 are provided, and the two light source modules 40 are disposed on both sides of the housing 10. An optical module 50 is disposed between the two light source modules 40, and the light source modules 40 are inclined toward the optical part 52 on the optical module 50, and the optical part 52 is inclined toward the mask 20. Specifically, the two light source modules 40 are inclinedly disposed in two light source receiving parts 13. The light source module 40 has a longitudinal plate-shaped configuration, including a light source substrate 41 extending along the length direction of the tunnel and a plurality of light sources 42 spaced apart from the light source substrate 41. The light source substrate 41 is slidably disposed in the light source receiving part 13 along the first slot 131, and the light sources 42 are inclined toward the receiving space 30 of the housing 10. The light emitted by the light source 42 is at least partially incident on the reflector 15 and, after being reflected by the reflector 15, is incident on the mask 20, and then emitted after being uniformly diffused by the mask 20 to illuminate the tunnel. In addition, the light emitted by the light source 42 also illuminates at least part of the optical module 50, and after being reflected by the optical module 50, it enters the mask 20 and exits through the mask 20.

[0055] Furthermore, a mask receiving portion 16 is disposed at the bottom of the housing 10 for receiving the mask 20. In this embodiment, the mask receiving portion 16 is a separate unit, including a first connecting portion 161 located at the bottom of the housing 10 and a second connecting portion 162 fixedly connected to the first connecting portion 161. The first connecting portion 161 and the second connecting portion 162 cooperate to receive and fix the mask 20. In other embodiments, the mask receiving portion 16 may also be integrally disposed, and the present invention is not limited thereto.

[0056] The first connecting portion 161 includes a second slot 1611 facing the receiving space 30 and a side connecting portion 1612 facing away from the receiving space 30. The second slot 1611 extends along the long side of the housing 10 to receive the face mask 20. The side connecting portion 1612 includes a T-shaped slot extending along the long side of the housing 10, which is recessed inward from the outer periphery of the housing 10 and has an outward opening for engaging and fixing with the second connecting portion 162.

[0057] The second connecting portion 162 has an L-shaped structure, including a first sidewall 1621 extending obliquely along the height direction and a second sidewall 1622 extending substantially horizontally from the lower end of the first sidewall 1621. A mating portion 1624 is formed on the first sidewall 1621 extending away from the first sidewall 1621. The mating portion 1624 is T-shaped and can be slidably fitted into the T-shaped slot of the side connecting portion 1612, so that the second connecting portion 162 is fixedly connected to the first connecting portion 161.

[0058] Furthermore, the second connecting portion 162 wraps around the outside of the side connecting portion 1612 to cooperate with the first connecting portion 161 to form a mask receiving portion 16. That is, the second connecting portion 162 is connected to the first side wall 1621 and the second side wall 1622, and the second side wall 1622 extends from the bottom of the first side wall 1621 toward the receiving space 30 to at least partially cover the second slot 1611 for supporting the mask 20. Specifically, the first side wall 1621 is attached to the outside of the side connecting portion 1612, and the second side wall 1622 is attached to the bottom of the side connecting portion 1612 and extends toward the receiving space 30 of the housing 10 to at least partially cover the second slot 1611 for supporting the mask 20. Preferably, an inclined guide surface 1623 is provided on the side of the second side wall 1622 opposite to the second slot 1611 to guide the mask 20 into the second slot 1611 of the first connecting portion 161.

[0059] Furthermore, the first joint 161 also includes a limiting plate 1613 extending from the bottom of the light source receiving part 13 toward the second slot 1611. The mask 20 is received in the second slot 1611 and is limited and snapped between the limiting plate 1613 and the second side wall 1622 to limit and fix the mask 20 in the height direction of the lamp 100.

[0060] The face shield 20 is flat and made of a light-transmitting or semi-light-transmitting material. The face shield 20 is used to receive light incident from the light source module 40 onto the reflector 15 and reflected by the reflector 15, as well as light incident from the light source module 40 onto the optical module 50 and reflected by the optical module 50. Preferably, the face shield 20 can uniformly distribute the received light to improve the illumination uniformity of the lamp 100.

[0061] Furthermore, the lamp 100 is provided with end caps 60 at both ends. The end caps 60 wrap around the outside of the housing 10 and are fixedly connected to the housing 10. The end cap 60 includes a main body 61 and a rim 62 extending vertically from the periphery of the main body 61. The rim 62 is fitted onto the outer periphery of the housing 10 and the faceplate 20 and is locked to the connecting part 17 of the housing 10 through several screw holes formed on the main body 61. By providing the end caps 60, dust or rainwater is prevented from entering the lamp 100, improving the sealing and safety of the lamp 100 and extending the service life of the lamp 100.

[0062] In summary, the optical module 50 of the present invention is applied to the lamp 100. By arranging a plurality of microstructures 521 along a first direction on the optical part 52 of the optical module 50, and each microstructure 521 includes a first surface 5211 and a second surface 5212 with an included angle, wherein the first surface 5211 faces away from the first direction and the second surface 5212 faces the first direction, and a warning coating is provided on the first surface 5211 or the second surface 5212, so that when the driver passes the optical module 50 along the first direction, the first surface 5211 is visible and the second surface 5212 is not visible; when passing the optical module 50 along the opposite direction from the first direction, the first surface 5211 is not visible and the second surface 5212 is visible. Thus, when the driver is driving in the correct direction, the warning coating is not visible, but when driving in the opposite direction, the warning coating is visible. Therefore, the driver can be promptly reminded of the driver driving in the opposite direction without affecting the lighting, thereby improving driving safety.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An optical module applied to a lamp (100), characterized in that, include: An optical unit (52) includes a plurality of microstructures (521) arranged side by side along a first direction. The microstructures (521) are serrated. Each microstructure (521) includes a first surface (5211) and a second surface (5212) arranged at an angle. The first surface (5211) faces away from the first direction, and the second surface (5212) faces the first direction. A warning coating is provided on the first surface (5211) or the second surface (5212). A connecting part (51) is provided for connecting the optical part (52) to the housing (10) of the lamp (100).

2. The optical module according to claim 1, characterized in that, Both the first surface (5211) and the second surface (5212) are provided with a coating, one of the first surface (5211) and the second surface (5212) is provided with the warning coating, and the coating on the other of the first surface (5211) and the second surface (5212) is a different color from the warning coating.

3. The optical module according to claim 2, characterized in that, The color of the coating on the other of the first surface (5211) and the second surface (5212) is the same as the color of the housing (10) of the lamp (100).

4. The optical module according to any one of claims 1 to 3, characterized in that, The connecting portion (51) extends in a direction parallel to the first direction, and there is a first included angle (a1) between the first surface (5211) and the connecting portion (51), and there is a second included angle (a2) between the second surface (5212) and the connecting portion (51), and the sum of the first included angle (a1) and the second included angle (a2) is an obtuse angle.

5. The optical module according to claim 4, characterized in that, The first surface (5211) and the second surface (5212) have a third included angle (a3), which is less than or equal to 80°.

6. The optical module according to claim 5, characterized in that, The cross-section of the microstructure (521) is triangular.

7. A lamp, characterized in that, include: A housing (10) and a mask (20) are provided, with a receiving space (30) formed between the housing (10) and the mask (20); The optical module (50) as described in any one of claims 1 to 6 is disposed within the receiving space (30); A light source module (40) is provided in the containment space (30), and the light emitted by the light source module (40) illuminates at least part of the optical module (50).

8. The lamp according to claim 7, characterized in that, Two light source modules (40) are provided, and the two light source modules (40) are disposed on both sides of the housing (10). The optical module (50) is disposed between the two light source modules (40). The light source module (40) is inclined toward the optical part (52) on the optical module (50), and the optical part (52) is toward the mask (20).

9. The lamp according to claim 7 or 8, characterized in that, The housing (10) has a reflective part (15) on the side facing the receiving space (30), and the light emitted by the light source module (40) is reflected by the reflective part (15) and then emitted through the mask (20).

10. The lamp according to claim 9, characterized in that, The light source module (40) includes a light source substrate (41) and a plurality of light sources (42) disposed on the light source substrate (41).

11. The lamp according to claim 9, characterized in that, The housing (10) includes a mask receiving portion (16) for receiving the mask (20), the mask receiving portion (16) is disposed below the light source module (40), the mask receiving portion (16) includes a first connecting portion (161) located at the bottom of the housing (10), and a second connecting portion (162) fixedly connected to the first connecting portion (161).

12. The lamp according to claim 11, characterized in that, The first joint (161) includes a second slot (1611) facing the receiving space (30) and a side joint (1612) facing away from the receiving space (30). The second joint (162) includes a first sidewall (1621) and a second sidewall (1622) connected together. The second sidewall (1622) extends from the bottom of the first sidewall (1621) toward the receiving space (30) to at least partially cover the second slot (1611).

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