Window units for buildings or structures

Abstract

The present disclosure provides a window unit for a building or structure. The window unit includes a first panel having an area that is transparent to at least a portion of visible light. The window unit also includes a second panel having an area that is transparent to at least a portion of visible light. The window unit further includes a spacer that spaces the first panel from the second panel. The spacer surrounds a space between the first panel and the second panel. A first edge region of the first panel extends beyond a peripheral protrusion of the spacer in a direction normal to the surface of the first panel. The window unit also includes a housing incorporating at least one electrical or electronic element that is electrically connected, indirectly or directly, to at least one other electrical component disposed within the window unit. The housing is disposed on or near the spacer and is at least partially disposed inside the peripheral protrusion of the first edge region of the first panel in a direction normal to the surface of the first panel.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to window units for buildings or structures, and in particular to window units that include electronic and / or electrical components, such as solar cells. [Background technology]

[0002] Buildings such as office towers, residential high rises and hotels use large amounts of exterior window panels and / or facades that incorporate glass panels.

[0003] These glass panels receive a large amount of sunlight, which heats the interior space and necessitates the use of air conditioning, which uses a large amount of energy worldwide.

[0004] PCT International Applications PCT / AU2012 / 000778, PCT / AU2012 / 000787 and PCT / AU2014 / 000814 (owned by the present applicant) disclose window units having panes that transmit visible light, but which include solar cells that absorb light, such as infrared light, to generate electricity.

[0005] Additionally, building windows may include other electrical components that often require control electronics, such as components that regulate light transmission. Locating the control electronics and providing electrical connections to such electrical components can be a challenge.

[0006] The present invention provides a technical improvement. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] PCT / AU2012 / 000778 [Patent Document 2] PCT / AU2012 / 000787 [Patent Document 3] PCT / AU2014 / 000814 Summary of the Invention [Problem to be solved by the invention]

[0008] In a first aspect, the present invention provides a window unit for a building or structure, the window unit comprising: a first panel having an area that is transparent to at least a portion of visible light; a second panel having an area that is transparent to at least a portion of visible light; a spacer spacing the first panel from the second panel, the spacer enclosing a space between the first and second panels, a first edge region of the first panel extending beyond a peripheral projection of the spacer in a direction normal to the surface of the first panel; and a housing incorporating at least one electrical or electronic element electrically connected, either indirectly or directly, to at least one other electrical component disposed within the window unit, the housing being located on or adjacent the spacer and at least partially inwardly of the peripheral projection of the first edge region of the first panel in a direction normal to the surface of the first panel.

[0009] The housing may be positioned completely inside the protrusion of the first edge region of the first panel in the direction normal to the surface of the first panel, thereby facilitating use of the window unit as an insulated glass unit (IGU) with standard dimensions and installation requirements.

[0010] The second panel may be substantially coextensive with the first panel, and a recess may be formed between the first edge region, the spacer, and the edge region of the second panel. The housing may be at least predominantly or completely disposed within the recess and at least predominantly embedded in butyl or the like. The window unit may have "flush" edges to further facilitate use of the window unit as an insulated glass unit (IGU) with standard dimensions and installation requirements.

[0011] The window unit may comprise other electrical components, which may for example be located on a surface of the first panel or the second panel.

[0012] In one embodiment, the other electrical component is provided in the form of at least one string of solar cells arranged along at least one edge of the first panel.

[0013] The electrical elements incorporated into the housing may include, for example, a diode, a battery, or a capacitor arrangement for storing electricity generated by at least one string of solar cells. Additionally, the electrical elements incorporated into the housing may include control electronics for controlling the electrical components of the window unit. Additionally, the electrical elements may include electrical leads or be provided in the form of electrical leads, and may or may not include additional electrical or electronic components. The electrical elements may further include electronic components such as a battery charge controller, a voltage regulator, and further controllers for controlling the functions of the window unit.

[0014] The window unit may include a first electrical connection for connecting another electrical component (such as at least one array of solar cells) to the electrical element incorporated within the housing. The first electrical connection may include, for example, an electrical lead. Additionally, the window unit may include a second electrical connection for connecting the electrical element to at least one other electrical component external to the window unit. The second electrical connection may include a pin or a socket. Additionally, the second electrical connection may include a wireless connection, such as a WIFI or Bluetooth connection.

[0015] The first panel may include a first component panel portion and a second component panel portion bonded together such that no air gap exists between the first and second component panel portions. At least one string of solar cells may be disposed between the first and second component panel portions. The first and second panels may be bonded to form a laminated structure. An adhesive may be used for bonding. In one embodiment, the adhesive has a refractive index at least similar to the refractive index of the material of the first and / or second component panel portions, which may be, for example, glass or a suitable polymeric material.

[0016] The window unit may include at least one string of solar cells, and the first and second component panel portions may sandwich the at least one string of solar cells. The first and second component panel portions, sandwiching the at least one string of solar cells, may be bonded together using polyvinyl butyral (PVB). The at least one string of solar cells may be disposed between sheets of PVB. In this embodiment, bonding is performed as follows: A PVB sheet may first be disposed between the first component panel portion and the at least one string of solar cells. The at least one string of solar cells is bonded to the first component panel portion by applying heat to the sheet of PVB material. An additional sheet of PVB material may be disposed over the at least one string of solar cells and spacers. An additional (thicker) PVB sheet may be disposed in areas of the first component panel portion where the solar cells and spacers are not disposed. A second component panel section is then placed on the exposed surface of the PVB sheet and bonded to the exposed surface of the PVB sheet by applying heat to form a laminate structure, with the solar cell sandwiched between the first component panel section and the second component panel section.

[0017] The first connection element of the housing can include an electrical lead, such as a substantially flat wire or ribbon, that electrically contacts the at least one string of solar cells, and a portion of the substantially flat wire or ribbon can be disposed through or within the PVB material between the first and second component panel portions and toward the at least one string of solar cells.

[0018] The spacer may be part of a spacer structure that includes corner spacer portions and elongated side portions.

[0019] The window unit may also include at least one of a suspended particle device, an electrochromic coating, an electrofluidic material, a liquid crystal device, a polymer-dispersed liquid crystal (PDLC) material, and an electrophoretic material. The electrical and electronic component may include a controller for controlling at least one of the suspended particle device, the electrochromic coating, the electrofluidic material, the liquid crystal device, and / or the polymer-dispersed liquid crystal (PDLC) material and the electrophoretic material.

[0020] The first component panel portion has a first major surface parallel to the first major surface of the second component panel portion, and the first major surface of the second panel portion has a surface area smaller than the area of ​​the first major surface of the first component panel portion, whereby the first component panel portion and the second component panel portion can be arranged such that a protrusion of the first component panel portion along a surface normal of the first component panel portion extends beyond the periphery of the second component panel portion. The first major surface of the second component panel portion faces the spacer, and electrical leads electrically connecting the at least one string of solar cells to electrical elements integrated into the housing can be directed around the edge of the second component panel portion. Because the edge of the first component panel portion protrudes beyond the edge of the second component panel portion, the electrical leads are protected. The electrical leads can be embedded in a layer, such as butyl, that forms the primary seal of the window unit.

[0021] In one embodiment, the window unit is a self-powered unit that does not necessarily require external wiring. In this embodiment, the window unit may include blinds or other electrical components that operate using electricity generated by, for example, at least one string of solar cells.

[0022] The at least one series of solar cells may include bifacial solar cells having opposing first and second surfaces, each having an area capable of absorbing light and generating electricity, the solar cells being oriented, in use, such that the first surface receives light from a light incident direction and the second surface receives light from a direction opposite the incident direction. The solar cells of the at least one series of solar cells may be arranged in a partially overlapping relationship, such as a shingle-like configuration. A housing may be provided in addition to the spacer. The housing may be spaced from the spacer but adjacent to it.

[0023] In a second aspect, the present invention provides a window unit for a building or structure, the window unit comprising: a first panel having an area that is transparent to at least a portion of visible light; a second panel having an area that is transparent to at least a portion of visible light; and a housing incorporating at least one electrical or electronic element electrically connected, indirectly or directly, to at least one other electrical component. A first edge region of the first panel extends beyond a peripheral protrusion of the second panel in a direction normal to the surface of the first panel. The housing is at least partially disposed within the protrusion of the first edge region of the first panel in a direction normal to the surface of the first panel.

[0024] The first panel and the second panel can be bonded together such that there is no air gap between the first panel and the second panel. At least one string of solar cells can be disposed between the first component panel section and the second component panel section. The first panel and the second panel can be bonded together to form a laminate structure.

[0025] A portion of the second panel can be disposed between the housing and the first panel.

[0026] The window unit may further comprise a third panel and a spacer spacing the third panel from the second panel.

[0027] The housing may be separate from the spacer and positioned adjacent to but separate from the spacer.

[0028] In one embodiment, the housing is positioned at or near an edge of the first panel between opposing corners of the first panel, hi one embodiment, the housing is positioned at or near a corner of the first panel, and two sides of the housing are positioned at or near adjacent edges of the first panel.

[0029] The present invention will be more fully understood from the following description of specific embodiments thereof, the description being made with reference to the accompanying drawings. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic top view of components of a window unit according to an embodiment of the present invention. [Figure 2] 2 is a schematic diagram of a cross section passing through plane A shown in FIG. 1. [Figure 3] 3 is a schematic side view of an edge of a component of the window unit shown in FIG. 1, looking in the direction of the arrow in FIG. 2. [Figure 4] FIG. 1 is an exploded view of components of a window unit according to an embodiment of the present invention. [Figure 5] FIG. 1 is a schematic top view of components of a window unit according to an embodiment of the present invention. [Figure 6] FIG. 1 is a schematic top view of components of a window unit according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] A window unit according to an embodiment of the present invention will now be described, first with reference to Figure 1. The window unit 100 may be provided in the form of, for example, a building window, a skylight, an automobile window, or any other structure that typically includes a window.

[0032] 1, the window unit 100 includes a first panel 102 spaced from a second panel (also not shown) by a spacer (not shown). The first panel 102 and the second panel are transparent to or transmit visible light through at least a portion of the visible light. The window unit 100 also includes an array of solar cells 106. The window unit 100 may be provided in the form of an insulated glass unit (IGU) and may include a frame (not shown).

[0033] The window unit 100 includes a housing for incorporating electrical or electronic components, which will be described below with reference to Figures 2 to 6. The window unit 100 according to an embodiment includes electrical and electronic components necessary for operation and control of the device. The electrical and electronic components are disposed within a housing 116, which also includes external electrical connections and feedthroughs. The housing 116 incorporates at least one electrical or electronic element that is electrically connected, either indirectly or directly, to at least one other electrical component disposed within the window unit.

[0034] The window unit 100 may include additional devices that may operate using electricity generated by the solar cell 106. For example, the window unit 100 may incorporate devices or systems such as blinds, curtains, air dampers, fans, sensors, electrochromic layers, motors, or pumps.

[0035] FIG. 2 is a side view of a corner of the window unit 100, and FIG. 3 is a schematic side view of the window unit 100 as viewed in the direction of the arrow in FIG. 2. Like components are designated by like reference numerals. FIGS. 2 and 3 show a first panel 102 spaced apart from a second panel 104 by a spacer 108. The spacer 108, which may comprise, for example, an aluminum extrusion, encloses the space between the first panel 102 and the second panel 104. The first panel 102 and the second panel 104, in this embodiment, comprise ultra-low iron glass. In one embodiment, a housing 116 is provided in addition to the spacer 108, such that the housing 116 is spaced apart from but adjacent to the spacer 108.

[0036] The first panel 102 includes a first component panel portion 110 and a second component panel portion 112 that are bonded together using an adhesive, such as polyvinyl butyral (PVB), in this example. In one example, the first component panel portion 110 and the second component panel portion 112 are bonded together so that there is no air gap between them. The solar cell 106 is sandwiched between the first component panel portion 110 and the second component panel portion 112 and embedded in a PVB lamination material 114.

[0037] The first component panel portion 110 and the second component panel portion 112 can be laminated as follows: A PVB sheet is first placed between the first component panel portion 110 and the solar cells 106. The PVB sheet is then exposed to heat so that the solar cells 106 bond to the first component panel portion 110. An additional sheet of PVB material is then placed on top of the solar cells 106. An additional (thicker) PVB sheet is then placed on the areas of the first component panel portion 110 where no solar cells 106 are located. The second component panel portion 112 is then bonded to the exposed surface of the PVB sheet, again by applying heat, to form a laminate structure in which the solar cells 106 are sandwiched between the first component panel portion 110 and the second component panel portion 112.

[0038] The first component panel portion 110 and the second component panel portion 112 each have parallel major surfaces. In one embodiment, the second component panel portion 112 has a larger perimeter than the first component panel portion 110, and the first component panel portion 110 and the housing 116 are disposed entirely with the perimeter of the second component panel portion 112 projecting in a direction normal to the surface of the second component panel portion 112. In other words, the first major surface of the first component panel portion 110 has a surface area that is smaller than the area of ​​the first major surface of the second component panel portion 112, such that the first component panel portion 110 and the second component panel portion 112 are disposed such that the perimeter of the second component panel portion 112 projecting in a direction normal to the surface of the first component panel portion 110 extends beyond the perimeter of the first component panel portion 110. This can help facilitate use of the window unit 100 as an insulated glass unit (IGU) with standard dimensions and installation requirements. In this example, the second panel 104 is substantially coextensive with the second component panel portion 112, and a recess is formed between the edges of the first and second component panel portions 110 and 112, the second panel 104, and the spacer 108. The housing 116 is placed within the formed recess, which is otherwise filled with butyl (not shown), to form the primary seal of the window unit. As a result, the window unit 100 has "flush" edges in this example, protecting not only the array of solar cells 106, but also the electrical components, or housings incorporating electrical components, and the electrical connections to the solar cells.

[0039] The housing 116, in this example, is 10 mm to 40 mm high and 10 mm to 20 mm wide, and is separated from the spacer 108 by a gap of 1 mm to 5 mm, which gap is filled with butyl or the like. In one example, a first major surface of the first component panel portion 110 faces the spacer 108, and electrical contacts 120 (flat wires, e.g., electrical leads) that electrically connect the at least one string of solar cells 106 to electrical elements integrated into the housing 116 are directed around an edge 140 of the second component panel portion 110.

[0040] In one embodiment, the string of solar cells 106 comprises bifacial shingle solar cells having active front and back surfaces. The string of solar cells 106 has electrical contacts 120 (flat wires) that are routed through the PVB material and then through the butyl material to the housing 116, where the electrical contacts are connected to additional electrical components. In one embodiment, the string of solar cells 106 is positioned such that, in use, the first (e.g., front) surface is oriented to receive light from a light incident direction and the second (e.g., back) surface is positioned to receive light from a direction opposite the incident direction. In one embodiment, the solar cells in the string of solar cells 106 are arranged in an overlapping relationship, such as a shingle-like configuration.

[0041] 4 is an exploded view of housing 116 and the components installed therein. Housing 116, in this embodiment, includes diode 118, electrical lead 122, and a female electrical coupling 123 configured to connect to a male coupling 125 of an external electrical or electronic component. Housing 116 is configured to connect to a series of solar cells 106, with diode 118 being a bypass diode 118. Housing 116 further includes a silicone seal 124. Housing 116 includes a body 126 with a removable lid 128 and is formed from a polymeric material.

[0042] In variations on the described embodiment, other electrical or electronic components may be incorporated into the housing 116. For example, the housing 116 may include a battery, a capacitor arrangement for storing electricity generated by at least one string of solar cells, a battery charge controller, and a voltage regulator. Additionally, the electrical elements incorporated into the housing 116 may include control electronics for controlling other electrical components of the window unit. The electrical elements may also include electronic components such as a battery charge controller, a voltage regulator, and further controllers for controlling the functionality of the window unit.

[0043] The location of the housing 116 can vary depending on the desired use of the window unit 100. For example, as shown in FIG. 5, in one embodiment, the window unit 200 has the housing 116 located near or at the edge 132 between the corners 130 of the window unit 200. In an alternative configuration, as shown in FIG. 6, in one embodiment, the window unit 200a has the housing 116a located at the corner 130a of the window unit 200a such that the housing is located near or at the adjacent edges 132 and 143. In such an embodiment, the housing 116a has 90° corners to follow the contour of the corner 130a. In such an embodiment, the housing 116a may have a female connector to assist in electrically connecting the housing 116a to an external electrical component.

[0044] Those skilled in the art will appreciate that alternative embodiments of the present invention may be provided in many different forms. For example, the second component panel portion 112 may not necessarily have a perimeter that extends beyond the perimeter of the first component panel portion 110. Furthermore, the second component panel portion 112 and the second panel 104 may not necessarily be coextensive. Furthermore, the housing 116 incorporating the electrical and electronic components may not necessarily be located completely within the perimeter projection of the second component panel portion 112.

[0045] The window unit may alternatively include any other type of solar cell, which may or may not be a bifacial solar cell, and further, may not necessarily be sandwiched between the component panel portions. For example, the solar cell may be applied to the inside surface of the first component panel portion 110 or otherwise disposed between the first component panel portion 110 and the second panel 104. Furthermore, the window unit may not include a solar cell, but rather other electrical components may be incorporated into the window unit (such as blinds), which may be disposed in the space between the first component panel portion 110 and the second panel 104, for example.

[0046] Additionally, the window unit may include one or more of a suspended particle device, an electrochromic coating, an electrofluidic material, a liquid crystal device, a polymer dispersed liquid crystal (PDLC) material, and an electrophoretic material, which may be arranged to adjust the transmittance of other optical properties of the window unit. The housing may incorporate a controller for controlling the devices, coatings, and the like. For example, the suspended particle device, the electrochromic coating, the electrofluidic material, the liquid crystal device, the polymer dispersed liquid crystal (PDLC) material, and the electrophoretic material may be arranged between the first component panel portion 110 and the second component panel portion 112.

[0047] In one embodiment, the window unit 100 / 200 / 200a may include one or more housings 116. For example, a first housing may be located on one side of the window unit 100 / 200 / 200a, and a second housing may be located on the other side of the window unit 100 / 200 / 200a. One housing may include a positive terminal and the other housing may include a negative terminal. The housing with the positive terminal may be located adjacent to the housing with the negative terminal. The housing with the positive terminal may be located away from the housing with the negative terminal, such as on an opposite or adjacent side of the window unit 100 / 200 / 200a. The housing with the positive terminal may be located at or toward one corner of an edge of the window unit 100 / 200 / 200a, and the housing with the negative terminal may be located at or toward the other corner of the same edge of the window unit 100 / 200 / 200a.

[0048] In one embodiment, the window unit 100 / 200 / 200a is a self-powered unit that does not necessarily require external wiring.

[0049] In the following claims and the foregoing description, unless otherwise required by context, express language, or necessary implication, the word "comprises" or variations such as "comprises" or "comprising" are used in an inclusive sense, i.e., to identify the presence of stated features, but are not used to exclude the presence or addition of further features in various embodiments of the present disclosure.

[0050] Where a prior art document is referenced in this specification, it should be understood that the reference is not an admission that the document forms part of the common general knowledge in the art in Australia or anywhere else.

[0051] Modifications and variations obvious to one skilled in the art are deemed to be within the scope of this disclosure.

Claims

1. 1. A window unit for a building or structure, said window unit comprising: a first panel having an area that is transparent to at least a portion of visible light; a second panel having an area that is transparent to at least a portion of visible light; a spacer spacing the first panel from the second panel, the spacer surrounding a space between the first panel and the second panel, a first edge region of the first panel extending beyond a peripheral projection of the spacer in a direction normal to the surface of the first panel; a housing incorporating at least one electrical or electronic element electrically connected, either indirectly or directly, to at least one other electrical component disposed within the window unit; A window unit, wherein the housing is positioned on or near the spacer and is at least partially positioned inside the peripheral protrusion of the first edge region of the first panel in the direction normal to the surface of the first panel.

2. 10. The window unit of claim 1, wherein the housing is positioned entirely inside the protrusion of the first edge region of the first panel in a direction normal to the surface of the first panel, thereby facilitating use of the window unit as an insulated glass unit (IGU) with standard dimensions and installation requirements.

3. 3. A window unit according to claim 1 or 2, wherein the second panel is substantially coextensive with the first panel, and a recess is formed between the first edge region, the edge region of the second panel, the spacer, and the edge region of the second panel.

4. 4. A window unit as claimed in claim 3, wherein the recess is at least predominantly filled with butyl or the like to form a primary seal for the window unit.

5. 5. A window unit according to claim 3 or 4, wherein the housing is at least mostly or completely disposed within the recess and is at least mostly embedded in butyl or the like.

6. 6. A window unit according to any one of the preceding claims, comprising at least one other electrical component.

7. 7. The window unit of claim 6, wherein the at least one other electrical component is provided in the form of at least one string of solar cells disposed along at least one edge of the first panel.

8. 8. A window unit according to any one of claims 1 to 7, wherein the electrical or electronic elements incorporated in the housing include at least one of a diode, a battery, a capacitor arrangement, control electronics for controlling electrical components, a battery charge controller, and a voltage regulator.

9. 9. A window unit according to any one of the preceding claims, wherein the electrical or electronic element comprises or is provided in the form of an electrical lead.

10. 10. A window unit according to any one of the preceding claims, comprising a first electrical connection for connecting the at least one other electrical component to the electrical or electronic element integrated within the housing.

11. 11. A window unit according to any one of the preceding claims, comprising a second electrical connection for connecting the electrical or electronic element to at least one other electrical component external to the window unit.

12. 12. A window unit as claimed in any one of claims 1 to 11, wherein the first panel comprises a first component panel portion and a second component panel portion joined together such that there is no gap between the first component panel portion and the second component panel portion.

13. 13. The window unit of claim 12, wherein at least one string of solar cells is disposed between the first component panel portion and the second component panel portion.

14. 14. A window unit as claimed in claim 12 or 13, wherein the first component panel portion has a first major surface parallel to a first major surface of the second component panel portion, the first major surface of the second panel having a surface area that is smaller than an area of ​​the first major surface of the first component panel portion, whereby the first component panel portion and the second component panel portion are arranged such that a protrusion of the first component panel portion along a surface normal of the first component panel portion extends beyond a periphery of the second component panel portion.

15. 15. The window unit of claim 14, wherein the first major surface of the second component panel portion faces the spacer and electrical leads electrically connecting the at least one string of solar cells to the electrical elements integrated into the housing are directed around an edge of the second component panel portion.

16. 16. The window unit of any one of claims 1 to 15, comprising at least one of a suspended particle device, an electrochromic coating, an electrofluidic material, a liquid crystal device, a polymer-dispersed liquid crystal (PDLC) material, and an electrophoretic material.

17. 17. A window unit according to any one of the preceding claims, wherein the window unit is a self-powered unit that does not necessarily require external wiring.

18. 18. The window unit of any one of claims 7 to 17, wherein the at least one series of solar cells comprises bifacial solar cells having opposing first and second surfaces, each with an area capable of absorbing light and generating electricity, wherein, in use, the first surface is oriented to receive light from an incident direction and the second surface is arranged to receive light from a direction opposite to the incident direction.

19. 20. The window unit of claim 18, wherein the solar cells of the string of solar cells are arranged in an overlapping relationship, such as a shingle-like configuration.

20. 20. A window unit according to any one of the preceding claims, wherein the housing is provided in addition to the spacer, the housing being spaced apart from the spacer but positioned adjacent to the spacer.

21. 1. A window unit for a building or structure, said window unit comprising: a first panel having an area that is transparent to at least a portion of visible light; a second panel having an area that is transparent to at least a portion of visible light; a housing incorporating at least one electrical or electronic element electrically connected, either indirectly or directly, to at least one other electrical component; a first edge region of the first panel extending beyond a peripheral protrusion of the second panel in a direction normal to a surface of the first panel; The window unit, wherein the housing is at least partially positioned inside a protrusion of the first edge region of the first panel in a direction normal to the surface of the first panel.

22. 22. The window unit of claim 21, wherein the first panel and the second panel are joined together such that there is no air gap between the first panel and the second panel.

23. 23. The window unit of claim 22, wherein at least one string of solar cells is disposed between the first component panel portion and the second component panel portion.

24. 24. The window unit of any one of claims 21 to 23, further comprising a third panel and a spacer spacing the third panel from the second panel, wherein the housing is separate from the spacer and is positioned adjacent to but spaced from the spacer.

25. 25. A window unit as claimed in any preceding claim, wherein the housing is located at or near an edge of the first panel, between opposing corners of the first panel.

26. 25. A window unit as claimed in any one of the preceding claims, wherein the housing is located at or near a corner of the first panel and two sides of the housing are located at or near adjacent edges of the first panel.

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