Reflectors, support structures for reflectors, and lighting devices

Abstract

An illumination device includes a funnel-shaped reflector comprising a plurality of first rods, a flexible material attached to the plurality of first rods, and a plurality of first connectors, wherein each of the plurality of first connectors is attached to the reflector at a position adjacent to one of the plurality of first rods; and a support structure configured to support at least one light source and including at least one socket and a plurality of second rods, wherein a first end of each of the plurality of second rods is attached to at least one socket; wherein a second end of each of the plurality of second rods is releasably connected to one of the first connectors, such that the connection position of the second end of each of the plurality of second rods to the corresponding connected first connector is adjustable.

Description

Technical Field

[0001] This invention relates to a funnel-shaped reflector, a support structure for the reflector, and an illumination device comprising the support structure and the reflector. The invention also relates to a method of using the illumination device. Background Technology

[0002] Here, the present invention relates to lighting devices that can be used for lighting purposes. For example, one example of such a lighting device is a softbox with a funnel-shaped reflector, which can be used for lighting, for example, on a film set.

[0003] The lighting device known from GB2425589 A has a funnel-shaped reflector with an adjustable connecting ring for attaching to light sources of different sizes.

[0004] Today, LED light sources are widely used for lighting purposes. These light sources come in a variety of forms, with varying numbers of LEDs per unit area and different lengths and widths of areas providing LED lighting.

[0005] We desire to be able to use a given reflector with various light sources, and to be able to use a given light source with various types of reflectors.

[0006] The technology known from GB 2425589 A does not offer sufficient flexibility to combine a large number of different available light sources with different types of reflectors. Summary of the Invention

[0007] Therefore, one object of the present invention is to provide a reflector and a support structure for the reflector that can be adapted to various types of light sources. Another object of the present invention is to provide a method of using a lighting device that facilitates its daily use in different locations.

[0008] According to an embodiment of the present invention, an illumination device includes a funnel-shaped reflector and a support structure configured to support at least one light source and to apply a supporting force to the funnel-shaped reflector to prevent the reflector from collapsing.

[0009] According to some embodiments, the connection between the support structure and the reflector is flexible, allowing support structures of different sizes to be used with the same reflector. Therefore, a support structure of a specific size can be selected that can be used with the desired light source, and due to the flexible construction of the connection between the reflector and the support structure, the selected support structure can be used with a given reflector.

[0010] According to some embodiments, the lighting device is formed by a funnel-shaped reflector and a support structure. The funnel-shaped reflector includes a plurality of first rods, a flexible material attached to the plurality of first rods, and a plurality of first connectors, each of which is attached to the reflector at a position adjacent to one of the plurality of first rods. The support structure is configured to support at least one light source and includes at least one socket and a plurality of second rods. Each second rod has a first end and a second end. The first end of each second rod is attached to the at least one socket, and the second end of each second rod is releasably connected to one of the first connectors, such that the connection position of the second end of each of the plurality of second rods to the corresponding connected first connector is adjustable.

[0011] A central axis can be provided for the support structure. If the support structure is attached to the funnel-shaped reflector, this central axis will approximately coincide with the central axis provided for the funnel-shaped reflector. According to some embodiments, multiple second rods extend away from the central axis, with the second ends of each second rod distributed around the central axis. When the funnel-shaped reflector is connected to the support structure, each second rod can elastically deform to apply a supporting force to each first rod of the funnel-shaped reflector, such that the supporting force prevents the reflector from collapsing.

[0012] According to some embodiments, the support structure includes at least one pivotable rod, wherein a first end of the pivotable rod is hinged to a socket, such that the pivotable rod is pivotable relative to the socket in a circumferential direction about a central axis. Here, pivoting of a second rod about the central axis in a direction orthogonal to the circumference is prevented. This pivotable rod increases the flexibility of the support structure in combination with various types of funnel-shaped reflectors.

[0013] According to some embodiments, the support structure includes a plurality of sockets, wherein the support structure has variable dimensions such that the distance between each pair of said plurality of sockets is adjustable. This embodiment allows a given support structure to be adapted to light sources of various sizes. Furthermore, the flexible connection between the first and second poles allows the use of the same reflector and the same support structure to accommodate light sources of various sizes.

[0014] According to some embodiments, each of the first connectors extends along one of the first rods by a length greater than 0.30 times, 0.45 times, or 0.60 times the length of the first rod. This extended arrangement of the first connectors provides flexibility for attaching the second ends of the second rods of various sizes of support structures.

[0015] Each first connector may include a plurality of notches distributed along a portion of a first rod, wherein a second end of one of the second rods may be inserted into one of these notches.

[0016] According to some embodiments, each first connector is a first distance from a first end of one of the first rods, wherein the first distance is greater than 0.05 times the length of one of the first rods, particularly greater than 0.1 times the length of one of the first rods, and particularly greater than 0.15 times the length of one of the first rods.

[0017] According to some embodiments, each first connector is a second distance from the second end of one of the first rods, wherein the second distance is greater than 0.05 times the length of one of the first rods, particularly greater than 0.1 times the length of one of the first rods, and particularly greater than 0.15 times the length of one of the first rods.

[0018] This configuration, compared to the previous configuration where each first connector had to extend along the full length of one of the first rods, not only saves material on the first connectors but, more importantly, enhances their adaptability. More specifically, the first connector does not necessarily have to be located at the first or second end of the first rod.

[0019] According to some embodiments, the support structure includes second connectors attached to each second end of each second rod, wherein each second connector is configured to connect to each first connector. For example, each first connector and each second connector may be a hook and loop portion of Velcro and / or a corresponding loop portion.

[0020] According to some embodiments, a method of using a lighting device includes removing a reflector and a support structure from a carrying case, wherein the reflector includes a plurality of first rods, a flexible material attached to the plurality of first rods, and a plurality of first connectors, wherein each of the plurality of first connectors is attached to the reflector at a position adjacent to one of the plurality of first rods, and wherein the support structure configured to support at least one light source includes at least one socket and a plurality of second rods; installing the lighting device by attaching a first end of each of the plurality of second rods to at least one socket; attaching a second end of each of the plurality of second rods to one of the plurality of first connectors; operating at least one light source; disassembling the lighting device by releasing the second end of each of the plurality of second rods from a corresponding one of the plurality of first connectors; releasing the first end of each of the plurality of second rods from the at least one socket; and placing the reflector and support structure into the carrying case. Attached Figure Description

[0021] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0022] here:

[0023] Figure 1 This is a plan view of the lighting device according to an embodiment;

[0024] Figure 2 It is along Figure 1The line II-II shown is the section intercepted by the line. Figure 1 A cross-sectional view of the lighting device shown;

[0025] Figure 3 This is a plan view of a portion of the lighting device according to the second embodiment;

[0026] Figure 4 This is a cross-sectional view showing a portion of a lighting device including a pivotable rod according to a third embodiment;

[0027] Figure 5 The lighting device according to the fourth embodiment corresponds to Figure 2 sectional view; and

[0028] Figure 6 This is a front view of a portable bag used for storing and transporting folded reflectors and support structures. Detailed Implementation

[0029] The following will refer to Figure 1 and Figure 2 The lighting device according to the first embodiment is described. Figure 1 This is a plan view of the lighting device 1 according to the first embodiment, and Figure 2 It is along Figure 1 The diagram shows a cross-sectional view of the lighting device 1 taken along line II-II.

[0030] The lighting device 1 is a softbox and includes a funnel-shaped reflector 3 and a support structure 5. The funnel-shaped reflector 3 includes eight rods 7 and a flexible material 9 attached to the eight rods 7. The funnel-shaped reflector 3 has a proximal end 11 and a distal end 13. A main axis 15 can be provided for the funnel-shaped reflector 3, wherein the main axis 15 is approximately the axis of symmetry of the funnel-shaped reflector. The circumference of the reflector around the axis 15 at the distal edge 13 is greater than the circumference of the reflector 3 around the axis 15 at the proximal edge 11. The reflector 3 can be made of any planar material, such as textile material, or any material suitable for conventional softboxes. For example, the planar material can be black on the outer surface of the reflector 3 and white or reflective on the inner surface of the reflector 3. The rods can be made of any flexible material, such as reinforcing fiber material.

[0031] The number of eight rods (7) is an exemplary number in this embodiment. Three, four, five, six, or seven rods, or nine or more rods, can be used. Figure 2 In the cross-section shown, each rod 7 is attached to the outer surface of the funnel-shaped reflector 3. However, each rod 7 may also be attached to the inside of the funnel-shaped reflector 3, or each rod may be embedded in the funnel-shaped reflector 3 or attached to the funnel-shaped reflector 3 by any other suitable means.

[0032] The support structure 5 includes a socket 21 and eight support rods 23 attached to the socket 21. The socket 21 includes... Figure 1 The plan view has a rectangular frame 25 and eight sleeves 27 inserted into the frame 25. The first end 29 of each rod 23 is inserted into one of the sleeves 27, such that the first end 29 of the rod 23 is rigidly attached to the socket 21.

[0033] The second end 31 of the rod 23 is attached to a connector 33, which is configured to attach to a connector 35, which in turn attaches to a funnel-shaped reflector 3. The connector 33 provides a notch 37 into which the second end 31 of the rod 23 is inserted. The notch may be formed, for example, by sewing or by adhesive bonding to a textile material attached to the reflector 3.

[0034] The connector 33 also includes a hook and loop portion 39 of the Velcro. The connector 35 includes a loop portion 38 of the Velcro, such that the connector 33 can be connected to the connector 35 by contacting the hook and loop portion 39 with the loop portion 38 provided on the surface of the connector 35. By connecting the connector 33 to the connector 35, the support structure 5 is connected to the funnel-shaped reflector 3.

[0035] The connector 35 extends over most of the length L of the rod 7 of the funnel-shaped reflector 3. Figure 2 In the example shown, except for the portion of length d1 at the near edge 11 of the funnel-shaped reflector 3 and the portion of length d2 at the far edge 13 of the funnel-shaped reflector 3, the connector 35 extends over the entire length L of the rod 7. Specifically, the length of the connector 35 is equal to the length L of the rod 7 minus d1 and d2. This length L-(d1+d2) is greater than 0.30 times L.

[0036] The connector 35 is positioned at a distance from the first end 17 of the rod 7, as indicated by the length d1. The first end 17 corresponds to the near edge 11 of the funnel-shaped reflector 3. According to... Figure 2 In the first embodiment shown, the first distance, i.e. the length d1, is set to be greater than 0.05 times the length of one of the rods 7, particularly greater than 0.1 times the length of one of the rods 7, and particularly greater than 0.15 times the length of one of the rods 7.

[0037] On the other hand, the connector 35 is at a second distance from the second end 19 of the rod 7, as indicated by the length d2. The second end 19 corresponds to the distal edge 13 of the funnel-shaped reflector 3. Figure 2 In the first embodiment shown, the second distance, i.e. the length d2, is set to be greater than 0.05 times the length of one of the rods 7, particularly greater than 0.1 times the length of one of the rods 7, and particularly greater than 0.15 times the length of one of the rods 7.

[0038] By constructing the first distance d1 and the second distance d2 as described above, some material can be saved for the connector 35. More importantly, the connector 35 does not necessarily have to be located at the first or second end of one of the rods 7, thereby improving the adaptability of the connection between the funnel-shaped reflector 3 and the corresponding support structure 5.

[0039] Since the connector 35 extends along most of the length of the rod 7 of the funnel-shaped reflector 3, the position where the connector 33 is attached to the connector 35 can be selected in the longitudinal direction of the rod 7. By appropriately selecting this position where the connector 33 is attached to the connector 35, a force (e.g., force applied to the rod 7 by the second end 31 of the rod 23) can be generated. Figure 2 (As indicated by the middle arrow 41). This force 41 is generated by each of the eight rods 23 distributed around axis 15, such that these eight forces 41 support the funnel-shaped reflector 3 in its desired shape and prevent the reflector 3 from collapsing. Each of these forces 41 is generated by the elastic deformation of the respective rod 23. The rods 23 generally have a straight shape. Due to the choice of the position where the connector 33 is attached to the connector 35, the rods 23 are bent into a curved shape, and they generate forces 41 that attempt to restore the rods 23 to their straight shape.

[0040] exist Figure 2 In the cross-section, it can be seen that rod 23 approaches rod 7 towards its distal edge 13. In other words, the distance between rod 23 and rod 7 decreases with the distance from connector 33.

[0041] Support structure 5 is configured to support at least one light source. Figure 1 and Figure 2 In the illustrated embodiment, a light source 45 is attached to the support structure 5. Specifically, the light source 45 is an LED light source having a light-emitting portion 46, a main body portion 47, and an electrical connector 48. The light source 45 is supported on the support structure 5 by a plate 49, which is mounted on the plate 49 and the plate 49 is fixed to the frame 25 of the socket 21 by screws 51.

[0042] One or more light sources 45 can be mounted on the plate 49 and supported on the support structure 5. In some embodiments, 10 or 100 or more LED light sources 45 are mounted on the plate 49 and supported on the support structure 5. In some cases, a support structure 5 with a larger frame 25 can be used to accommodate a greater number of light sources 45. This larger frame 25 results in a different position of the sleeve 27 compared to the first embodiment. Figure 1 and Figure 2 The position shown. However, since the connection position of connector 33 and connector 35 can be selected by the user, support structures 5 of frame 25 with different sizes can be used with the same funnel-shaped reflector 3.

[0043] Figure 3This is a plan view of a portion of the lighting device 1a according to the second embodiment. The lighting device 1a of the second embodiment has... Figure 1 and Figure 2 The structure shown is similar to that of the lighting device 1 according to the first embodiment, wherein the components of the lighting device 1a, which have similar structures and functions to those of the lighting device 1, are indicated by the same reference numerals plus the letter "a". The following will be combined with... Figure 3 The second embodiment will be described, focusing primarily on components that differ from those in the first embodiment. Other components in the second embodiment that are similar to those in the first embodiment will not be referred to further. Figure 3 For further explanation, please refer to the description of the first embodiment and the summary of the invention section of the specification to gain a full understanding of these components.

[0044] Lighting device 1a includes those not in Figure 3 The image further shows a funnel-shaped reflector and a support structure 5a with four sockets 21a. Each socket 21a has two sleeves 27a into which the ends of the rods of the support structure 5a are inserted.

[0045] The socket 21a is provided by an elongated rectangular strip, the ends of which are inserted into the edge elements 61, such that the four edge elements 61 and the socket 21a form a rectangular frame 25a. The socket 21a can be inserted into the edge elements 61 to a depth e, which can be selected by the user, wherein the position of the socket 21a in the edge elements 61 can be determined by, for example, a screw (…). Figure 3 (Not shown in the image) Fixed. By appropriately selecting the depth e, the distances f and g between each pair of sockets 21a can be adjusted. Therefore, the dimensions of the support structure 5a can be adjusted to the dimensions required to attach the desired light source or light source array to the support structure 5a. Furthermore, due to the construction of the connector 35 of the funnel-shaped reflector 9, the same support structure 5a, adjusted to variable dimensions f and g, can be used with the same funnel-shaped reflector 9.

[0046] The following will refer to Figure 4 The third embodiment is described below. Figure 4 A cross-sectional view of a portion of the lighting device 1b according to the third embodiment is shown.

[0047] The lighting device 1b of the third embodiment has the same characteristics as according to... Figure 1 and Figure 2 The lighting device 1 of the first embodiment shown has a similar construction, wherein components of the lighting device 1b having similar structures and functions to those of the lighting device 1 are indicated by the same reference numerals plus the letter "b". The following will be combined with... Figure 4The third embodiment will be described, focusing primarily on components that differ from those in the first embodiment. Other components in the third embodiment that are similar to those in the first embodiment will not be referred to further. Figure 4 For further explanation, please refer to the descriptions of the first and second embodiments and the summary of the invention section of the specification to gain a full understanding of these components.

[0048] Lighting fixture 1b and above Figures 1 to 3 The main difference between the lighting devices 1 and 1a shown is how the rod 23b is attached to the socket 21b. Figure 4 In this configuration, the end 29b of rod 23b is bent at approximately 90° relative to the main portion of rod 23b and inserted into a through hole 65, which is located within socket 21b. The end 29b of rod 23b is secured in the through hole 65, for example, by a nut 67. This configuration allows rod 23b to rotate about axis 69, such as... Figure 4 As indicated by arrow 71, axis 69 is parallel to Figure 4 The central axis 15b of the funnel-shaped reflector, not shown in the diagram. However, this construction does not allow for... Figure 4 The actual rotation is indicated by arrow 73. In other words, rod 23b is prevented from pivoting about the central axis 15b in a direction 73 orthogonal to the circumferential direction 71. This ensures that each rod 23b can bend to generate a force for supporting the funnel-shaped reflector (see [link]). Figure 2 Arrow 41 in the diagram). However, when the dimensions of the support structure 5b are (see...) Figure 3 When the distances f and g in the middle change, the pivoting about axis 69 in direction 71 provides some degrees of freedom for attaching the other ends of each rod 23b to the connectors of each rod arranged close to the funnel-shaped reflector.

[0049] The following will refer to Figure 5 The fourth embodiment will be described. The lighting device 1c of the fourth embodiment has the same characteristics as according to... Figure 1 and Figure 2 The lighting device 1 shown in the first embodiment has a similar construction, wherein components of the lighting device 1c having similar structures and functions to those of the lighting device 1 are indicated by the same reference numerals plus the letter "c". Reference will be made below. Figure 5 The fourth embodiment will be described, focusing primarily on components that differ from those in the first embodiment. Other components in the fourth embodiment that are similar to those in the first embodiment will not be referred to further. Figure 5 For further explanation, please refer to the descriptions of the first, second, and third embodiments and the summary of the invention section of the specification to gain a full understanding of these components.

[0050] Figure 5 Is with Figure 2A cross-sectional view similar to that of a portion of the lighting device 1c. The lighting device 1c is... Figure 1 and Figure 2 The main difference in the lighting device 1 shown is the connection structure between the second end 31c of the rod 23c of the support structure 5c and the connector 35c attached to the funnel-shaped reflector 3c.

[0051] exist Figure 5 In the illustrated embodiment, the connection between each rod 23c and the funnel-shaped reflector 3c is not provided by Velcro. Specifically, the connector 35c includes a plurality of notches 75 distributed along a portion of the rod 7c of the funnel-shaped reflector 3c. Except for a portion having a length d1 at the outer edge 11c of the funnel-shaped reflector 3c and a portion having a length d2 at the distal end 13c of the funnel-shaped reflector 3c, the portion having the notches 75 extends along the length L of the rod 7c.

[0052] Multiple notches 75 along the length L of the rod 7c provide that the end 31c of the rod 23c can be connected to multiple locations of the funnel-shaped reflector 3c, so that the same funnel-shaped reflector 3c can be used with support structures 5c of different sizes.

[0053] The extension length of connector 35c is equal to the length L of rod 7c minus d1 and d2. In various embodiments, this length L-(d1+d2)>0.30×L.

[0054] Figure 6 This is a front view of a carrying case 81 for storing and transporting the folded funnel-shaped reflector 3 and the support structure 5. The carrying case 81 consists of a quasi-rectangular body (denoted by 83) made of a lightweight material, such as polyester. The body 83 has an opening 85. The opening 85 is configured large enough that the folded funnel-shaped reflector 3 and the support structure 5, including at least one socket 21 and multiple second rods 23, can be easily inserted into the body 83. The opening 85 is provided with a locking mechanism 89 to close the opening 85 during transport. The locking mechanism 89 can be a zipper or Velcro. For ease of transport of the lighting device, a pair of handles 87 are attached near the opening 85 of the carrying case 81.

[0055] After transporting the lighting equipment to the target location, such as a film set or shooting location, first remove the folded reflector 3 and the support structure 5, including at least one socket 21 and multiple second rods 23, from the carrying case 81. Then unfold the folded reflector 3 into a funnel-shaped reflector 3, as shown. Figure 1 As shown. Thereafter, the first end 29 of each of the plurality of second rods 23 is attached to at least one socket 21 via a corresponding sleeve 27. The second end 31 of each of the plurality of second rods 23 is attached to one of the first connectors 35.

[0056] According to one embodiment, each first connector 35 includes a plurality of recesses 75 distributed along at least a portion of one of the plurality of first rods 7, such that a second end 31 of each of the plurality of second rods 23 may be inserted into one of the plurality of recesses 75 according to the length of each of the plurality of second rods 23 and the size of at least one socket 21.

[0057] According to another embodiment, each first connector 35 includes a hook and loop portion 39 or a loop portion 38 of Velcro. When each first connector 35 includes a hook and loop portion 39, a complementary loop portion 38 is attached to a second end 31 of each of the plurality of second rods 23. When each first connector 35 includes a loop portion 38, a complementary hook and loop portion 39 is attached to a second end 31 of each of the plurality of second rods 23.

[0058] After attaching the second end 31 of each of the plurality of second rods 23 to each of the first connectors 35, at least one light source can be operated. Thereafter, the second end 31 of each of the plurality of second rods 23 can be detached from the corresponding one of the plurality of first connectors 35, and the first end 29 of each of the plurality of second rods 23 can be detached from the corresponding sleeve 27 of at least one socket.

[0059] At this stage, the reflector 3, multiple second rods 23, and at least one socket 21 are disconnected from each other. Then, the funnel-shaped reflector 3 can be easily folded into a trapezoidal shape, as shown below. Figure 6 As shown in Figure 3.

[0060] Finally, the folded reflector 3, multiple second rods 23 and at least one socket 21 can be inserted into the carrying bag 81 for storage and transportation.

Claims

1. An illumination device, characterized by include: Funnel-shaped reflector, the funnel-shaped reflector comprising: Multiple first shots, Flexible material, the flexible material being attached to the plurality of first rods, and A plurality of first connectors, wherein each of the plurality of first connectors is attached to the reflector at a position adjacent to one of the plurality of first rods; and A support structure configured to support at least one light source, and comprising: At least one socket, and Multiple second shots, Each of the plurality of second rods has a first end and a second end; Wherein, the first end of each of the plurality of second rods is attached to the at least one socket; The second end of each of the plurality of second rods is releasably connected to a corresponding one of the plurality of first connectors; as well as The connection position of the second end of the second rod to the corresponding first connector is adjustable along the first rod and the adjustment length is greater than 0.30 times the length of the first rod.

2. The lighting device according to claim 1, characterized in that, The supporting structure has a central axis; Each of the plurality of second rods extends away from the central axis; and The second ends of each of the plurality of second rods are distributed around the central axis.

3. The illumination device of claim 2, wherein The plurality of second rods includes at least one pivotable rod. Wherein, the first end of the at least one pivotable rod is hinged to the at least one socket, such that the pivotable rod is pivotable relative to the at least one socket in a circumferential direction about the central axis.

4. The illumination device of claim 3, wherein The pivoting of the pivotable rod about the central axis in a direction orthogonal to the circumferential direction is prevented.

5. The illumination device according to any one of claims 1 to 4, characterized in that The plurality of second rods elastically deform to apply a supporting force to the plurality of first rods of the funnel-shaped reflector; and The supporting force prevents the reflector from collapsing.

6. The illumination device according to any one of claims 1 to 5, characterized in that The support structure includes multiple sockets; and The support structure has variable dimensions, making the distance between each pair of sockets adjustable.

7. The illumination device according to any one of claims 1 to 6, characterized in that At least one of the plurality of first connectors includes a plurality of notches distributed along at least a portion of one of the first rods; and The second end of one of the plurality of second rods is inserted into one of the plurality of recesses.

8. The illumination device according to any one of claims 1 to 7, characterized in that The support structure includes at least one second connector, which is attached to the second end of one of the second rods. The second connector is configured to be connected to one of the plurality of first connectors.

9. The illumination device of claim 8, wherein, The first connector is the hook and loop portion of the hook and loop fastener, and the second connector is the loop portion of the hook and loop fastener; or The first connector is the loop portion of the Velcro, and the second connector is the hook portion of the Velcro.

10. The illumination device of any one of claims 1 to 9, wherein, The reflector has a near edge and a far edge; The perimeter of the reflector at its distal edge is greater than the perimeter of the reflector at its proximal edge; as well as Each of the plurality of first rods extends from the near edge of the reflector to the far edge of the reflector.

11. The illumination device of any one of claims 1 to 10, wherein, At least one of the plurality of first connectors extends along one of the plurality of first rods for a length greater than 0.45 times the length of one of the plurality of first rods, and in particular greater than 0.60 times the length of one of the plurality of first rods.

12. The illumination device of any one of claims 1-11, wherein, Each of the plurality of first connectors is at a first distance from the first end of each of the plurality of first rods, wherein the first distance is greater than 0.05 times the length of one of the plurality of first rods, particularly greater than 0.1 times the length of one of the plurality of first rods, and particularly greater than 0.15 times the length of one of the plurality of first rods.

13. The illumination device of any one of claims 1-12, wherein, Each of the plurality of first connectors is at a second distance from the second end of each of the plurality of first rods, wherein the second distance is greater than 0.05 times the length of one of the plurality of first rods, particularly greater than 0.1 times the length of one of the plurality of first rods, and particularly greater than 0.15 times the length of one of the plurality of first rods.

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