Substrate mounting frame, frame joined body, and LED vision

Abstract

The present invention provides a substrate mounting frame which can achieve a reduction in weight while ensuring mechanical strength. A substrate mounting frame 1 is made of a synthetic resin, comprises a foam layer 5 which is provided in a part thereof, a non-foam layer 6 which is laminated on the forward side of the foam layer 5, and a non-foam layer 7 which is laminated on the backward side of the foam layer 5, and has a thick part 4 which has a thickness of not less than 7 mm in the forward-backward direction. In the thick part 4, the foam layer 5 has a thickness T2 of not less than 50% but less than 98% of the thickness T1 (total thickness) of the substrate mounting frame 1 (thick part 4) in the forward-backward direction. By forming the thickness T1 of the thick part 4 relatively thick and relatively increasing the thickness of the foam layer 5, a reduction in weight is achieved while mechanical strength is ensured.

Description

Substrate mounting frame, frame joint and LED vision

[0001] The present disclosure relates to a board mounting frame made of synthetic resin for mounting an LED module board of an LED vision.

[0002] 2. Description of the Related Art In recent years, as disclosed in Non-Patent Document 1, large displays called LED visions (LED walls) equipped with light-emitting diodes (LEDs) have come into practical use.

[0003] LED screens are formed by connecting multiple units vertically or horizontally. Typically, each unit consists of an LED module board, which is a collection of LED elements, and a board mounting frame that serves as the base for the LED module board. It measures approximately 50 cm high and 50 cm wide or more. Because the units do not have a surrounding frame, connecting multiple units allows for the creation of a large, seamless display. LED screens offer the advantage of being able to change the display size and aspect ratio according to the purpose by adjusting the number of connected units, and of facilitating maintenance by allowing for unit-by-unit part replacement. Furthermore, LED screens offer high brightness, providing excellent visibility even during the day or from a distance, making them appealing to consumers. Waterproof LED screens are also available. As a result, LED screens are widely used in storefronts, outdoor advertising on building rooftops, interior spaces in commercial facilities, and events.

[0004] https: / / www.fujifilm.com / jp / ja / business / signage / digital-signage / column / knowledge / led-vision

[0005] Conventional board mounting frames are made of metal such as aluminum. Therefore, the units themselves are heavy. This results in poor work efficiency when transporting, connecting, and dismantling connected units. In particular, LED vision displays used at events, concerts, and other venues must be installed at each venue, so there is a need to improve work efficiency when transporting, connecting, and dismantling units. To improve work efficiency when transporting, connecting, and dismantling units, it is necessary to reduce the weight of the board mounting frame. However, simply making the board mounting frame thinner to reduce weight can result in the board mounting frame being unable to withstand the load when multiple units are connected, potentially resulting in damage to the board mounting frame.

[0006] Therefore, an object of the present disclosure is to provide a board mounting frame that can be made lighter while ensuring a predetermined mechanical strength against the load when units are connected.

[0007] In order to solve the above problems, the present disclosure provides a board mounting frame for mounting an LED module board for an LED vision. The board mounting frame is made of synthetic resin. At least a portion of the board mounting frame includes a foam layer, a first non-foam layer laminated in front of the foam layer, and a second non-foam layer laminated behind the foam layer.

[0008] According to the board mounting frame of the present disclosure, it is possible to reduce the weight while ensuring a predetermined mechanical strength.

[0009] FIG. 1 is an external perspective view of a board mounting frame according to a first embodiment. FIG. 2 is a cross-sectional view of the thick-walled portion shown in FIG. 1. FIG. 3 is an external perspective view of a frame assembly according to this embodiment. FIG. 4 is an external perspective view of a frame assembly having a movement restricting portion formed therein. FIG. 5 is an enlarged perspective view of the frame assembly shown in FIG. 4. FIG. 6 is an external perspective view showing a modified example of the board mounting frame. FIG. 7 is an enlarged perspective view showing the connected state of the board mounting frame shown in FIG. 6. FIG. 8 is a schematic diagram showing how an LED vision is constructed by attaching an LED module board to the board mounting frame. FIG. 9 is an external perspective view of a board mounting frame according to a second embodiment. FIG. 10 is a cross-sectional view taken along line X-X in FIG. 9.

[0010] The inventors first considered forming the board mounting frame from a synthetic resin to reduce its weight, and then increasing the thickness of the synthetic resin board mounting frame to obtain a predetermined mechanical strength. However, simply increasing the thickness of the board mounting frame results in warpage or sink marks (surface depressions) after resin molding, such as injection molding, significantly reducing the dimensional accuracy of the board mounting frame. For these reasons, no board mounting frames made from synthetic resin have been proposed.

[0011] After extensive research, the inventors discovered that foam molding at least a portion of the board mounting frame can reduce weight while increasing the thickness of the board mounting frame and improving mechanical strength. The inventors also discovered that increasing the thickness of the board mounting frame through foam molding can suppress warpage, and that excellent dimensional accuracy can be achieved by pressing the surface of a non-foamed layer formed on the outer surface of the board mounting frame against a mold during foaming of the foamed layer formed inside the board mounting frame, thereby suppressing the occurrence of sink marks. The board mounting frame of the present disclosure was completed by the inventors based on these findings.

[0012] (Configuration 1) A board mounting frame according to an embodiment of the present disclosure is a board mounting frame to which an LED module board of an LED vision is attached. The board mounting frame is made of synthetic resin. At least a portion of the board mounting frame includes a foam layer, a first non-foam layer laminated in front of the foam layer, and a second non-foam layer laminated behind the foam layer.

[0013] In this way, by forming a foam layer between the first non-foam layer and the second non-foam layer, weight can be reduced and the thickness of the board mounting frame in the front-to-rear direction can be increased to ensure mechanical strength. Here, mechanical strength refers to the bending rigidity of the board mounting frame. In other words, mechanical strength refers to the resistance of the board mounting frame to deflection due to a bending load. Furthermore, by increasing the thickness of the board mounting frame through foam molding, warpage of the board mounting frame after resin molding can be suppressed. Furthermore, by suppressing the occurrence of sink marks through foam molding, the dimensional accuracy of the board mounting frame can be improved.

[0014] (Configuration 2) In the board mounting frame described in Configuration 1, the board mounting frame may have a lower frame portion, a left frame portion, and a right frame portion, and may have a rectangular frame shape formed by these frame portions. At least four corners of the board mounting frame may include the foam layer, the first non-foam layer, and the second non-foam layer. This allows the weight of the board mounting frame to be reduced while improving the mechanical strength of the four corners that receive the greatest load when the LED module board is attached. This allows the weight of the board mounting frame to be reduced while more effectively ensuring the mechanical strength of the board mounting frame.

[0015] (Configuration 3) In the board mounting frame according to Configuration 2, the board mounting frame may further include a vertical bar connecting the upper frame portion and the lower frame portion. The vertical bar may include the foam layer, the first non-foam layer, and the second non-foam layer. This allows the board mounting frame to be made lighter while further improving its mechanical strength in the vertical direction.

[0016] (Configuration 4) In the board mounting frame described in Configuration 2, the board mounting frame may further include a plate-shaped portion connected to at least two of the upper frame portion, the lower frame portion, the left frame portion, and the right frame portion. The plate-shaped portion may include the foam layer, the first non-foam layer, and the second non-foam layer. This allows the plate-shaped portion to improve the rigidity of the board mounting frame. This allows the board mounting frame to be made lighter while further improving its mechanical strength.

[0017] (Configuration 5) In the board mounting frame according to Configuration 1, the board mounting frame may include the foam layer, the first non-foam layer, and the second non-foam layer, and may have a thick portion having a thickness of 7 mm or more in the front-to-rear direction. The foam layer may have a thickness in the thick portion that is 50% or more but less than 98% of the total thickness of the board mounting frame in the front-to-rear direction. This more effectively ensures the mechanical strength of the board mounting frame while reducing its weight. Furthermore, it more effectively suppresses the occurrence of warpage and sink marks.

[0018] (Configuration 6) In the board mounting frame described in Configuration 1, the mounting surface of the LED module board located in front of the board mounting frame may have a flatness of 0.3 mm or less. By making the thickness in the front-to-rear direction relatively large as in the board mounting frame of Configuration 2, the flatness of the mounting surface of the LED module board can be reduced. As a result, when the LED module board is mounted on the mounting surface, misalignment between the LED module board and other LED module boards mounted on other board mounting frames can be reduced, ensuring the visibility of the LED vision.

[0019] (Configuration 7) In the board mounting frame according to any one of configurations 1 to 6, the synthetic resin may contain a filler, thereby more effectively ensuring the mechanical strength of the board mounting frame.

[0020] (Configuration 8) In the board mounting frame according to any one of Configurations 1 to 7, the synthetic resin may contain polycarbonate. Polycarbonate is available at low cost and has excellent moldability and strength, making it suitable for use as a resin material for the board mounting frame.

[0021] (Configuration 9) In the board mounting frame according to any one of configurations 1 to 8, the board mounting frame may have a rectangular frame shape including an upper frame portion, a lower frame portion, a left frame portion, and a right frame portion. When a load of 30 kg is applied to the center of the upper end surface of the upper frame portion, the amount of deformation of the upper frame portion may be 0.4 mm or less. By reducing the amount of deformation of the upper frame portion, it is possible to achieve excellent dimensional accuracy and weight reduction while maintaining a predetermined mechanical strength.

[0022] (Configuration 10) In a frame joint for connecting a plurality of adjacent board mounting frames according to any one of configurations 1 to 9, a pair of adjacent board mounting frames may be connected so that their respective joint surfaces face each other. One of the pair of board mounting frames may have a mating portion on the joint surface facing the other board mounting frame. The other board mounting frame may have a mated portion into which the mating portion can be mated. The pair of board mounting frames are connected by mating the mating portion with the mated portion. This makes it possible to easily connect one board mounting frame to the other board mounting frame by mating the mating portion with the mated portion. Furthermore, because the board mounting frames are made of synthetic resin, the mating portion and the mated portion can be easily formed by resin molding.

[0023] (Configuration 11) In the frame assembly according to Configuration 10, the mounting surface of one board mounting frame to which the LED module is attached and the mounting surface of the other board mounting frame to which the LED module is attached may be flush with each other when the one board mounting frame and the other board mounting frame are connected. This makes it possible to prevent misalignment between the LED module board attached to the mounting surface and other LED module boards attached to other board mounting frames when the LED module board is attached to the mounting surface, thereby ensuring visibility of the LED vision.

[0024] (Configuration 12) In the frame assembly according to Configuration 10 or 11, at least one of the joint surfaces of one board mounting frame and the other board mounting frame may have a movement restraint portion for restraining movement of the one board mounting frame and the other board mounting frame relative to each other in the front-rear and left-right directions while they are connected. This makes it possible to restrain movement of the board mounting frames relative to each other in the front-rear and left-right directions, suppressing misalignment and gaps between the board mounting frames and ensuring visibility of the LED vision.

[0025] (Configuration 13) In the frame assembly according to Configuration 10 or 11, the engaging portion and the engaged portion may be configured so that one of the engaging portion and the engaged portion slides relative to one another in the front-to-rear direction and is engaged, and so that the one board mounting frame and the other board mounting frame are prevented from moving relative to each other in the up-down and left-right directions while they are connected. This prevents the connected board mounting frames from moving relative to each other in the up-down and left-right directions. This prevents misalignment and gaps between adjacent board mounting frames, ensuring the visibility of the LED vision.

[0026] (Configuration 14) In the frame assembly according to Configuration 13, the mating portion is a protrusion that protrudes above the mating surface of the other board mounting frame. The mated portion is a recess that is recessed above the mating surface of the one board mounting frame so that the mating portion is mated with and fixed vertically relative to the mated portion. This achieves the configuration of the frame assembly of Configuration 13.

[0027] (Configuration 15) In the frame assembly according to any one of Configurations 10 to 14, a gap formed between the joint surface of one board mounting frame and the joint surface of the other board mounting frame may be 0.3 mm or less in a temperature range of −30° C. to 60° C. This reduces the gap between the board mounting frames and ensures visibility of the LED vision in an environment where the LED vision is used or where the LED module board is generating heat.

[0028] (Configuration 16) An LED vision screen includes the board mounting frame according to any one of configurations 1 to 9 and an LED module board mounted on the board mounting frame. This allows the board mounting frame to be easily connected to other adjacent board mounting frames. This makes it easy to assemble the LED vision screen. Furthermore, because the board mounting frame that supports the LED module board is one that can be made lightweight while maintaining mechanical strength, an LED vision screen that can be made lightweight while maintaining mechanical strength can be realized.

[0029] <Embodiment 1> A first embodiment of a board mounting frame and a frame assembly according to the present disclosure will be described in detail below with reference to Figures 1 to 7. Note that identical or corresponding components in the figures are designated by the same reference numerals, and the same description will not be repeated. To facilitate understanding of the description, the drawings referred to below show simplified or schematic configurations, and some components are omitted. In each figure, the symbol F indicates the front, the symbol B indicates the rear, the symbol R indicates the right, the symbol L indicates the left, the symbol U indicates the top, and the symbol D indicates the bottom.

[0030] [Board Mounting Frame] The board mounting frame 1 according to the present disclosure is made of synthetic resin. As shown in FIG. 1 , the board mounting frame 1 has an outer frame 2 and an inner frame 3. As shown in FIGS. 1 and 2 , the board mounting frame 1 also has a thick portion 4, a foam layer 5, a non-foamed layer 6 (first non-foamed layer), a non-foamed layer 7 (second non-foamed layer), and a mounting surface 8. Note that FIG. 2 is a cross-sectional view showing a cross section of a portion of the thick portion 4 shown in FIG. 1 taken in the front-to-rear direction so as to include the foam layer 5. The board mounting frame 1 also has a mating portion 9 and a mated portion 10 for connecting to another board mounting frame 1; these mating portion 9 and mated portion 10 will be described in detail in the description of the frame assembly 100, which will be described later.

[0031] The outer frame 2 has a rectangular frame shape including an upper frame portion 21, a lower frame portion 22, a left frame portion 23, and a right frame portion 24. The outer frame 2 has mating portions 9 and mated portions 10 on its outer peripheral surface for connecting to other board mounting frames 1. The shape of the outer frame 2 is not limited to a rectangular frame shape and is not particularly limited as long as it can be connected to other board mounting frames 1 with as little gap as possible. Furthermore, the dimension of one side of the rectangular outer frame 2, i.e., the length of each of the upper frame portion 21, lower frame portion 22, left frame portion 23, and right frame portion 24, is not particularly limited, but is preferably 30 cm or more and 200 cm or less from the viewpoint of ease of transporting, connecting, and disassembling the board mounting frame 1.

[0032] The inner frame 3 is formed to connect opposing or adjacent sides of the outer frame 2. In this embodiment, as shown in FIG. 1 , the inner frame 3 is composed of a vertical bar 31 located in the left-right center of the outer frame 2 and connecting the upper frame portion 21 and the lower frame portion 22, and a horizontal bar 32 located in the up-down center of the outer frame 2 and connecting the left frame portion 23 and the right frame portion 24. The inner frame 3 may have various shapes, such as a lattice pattern or a diagonal lattice pattern. The inner frame 3 may have multiple vertical bars 31 and multiple horizontal bars 32. The vertical bars 31 may be located at a position other than the left-right center of the outer frame 2. The horizontal bars 32 may be located at a position other than the up-down center of the outer frame 2. The inner frame 3 may not have the vertical bars 31. The inner frame 3 may not have the horizontal bars 32.

[0033] The thick portions 4 may be included in the outer frame 2. The thick portions 4 have a thickness T1 in the front-to-rear direction that is greater than the thickness T1 of the board mounting frame 1 other than the thick portions 4. In this embodiment, the thick portions 4 are formed at the corners (four corners) of the outer frame 2, the upper frame portion 21, the lower frame portion 22, the left frame portion 23, and the right frame portion 24 between the corners of the outer frame 2, and the inner frame 3. That is, the thick portions 4 are portions of the outer frame 2 and the inner frame 3, including the areas indicated by dashed lines in FIG. 1 (foam layer 5, described later). Note that the thick portions 4 may be selectively provided in a portion of at least one of the outer frame 2 and the inner frame 3, or may be distributed in multiple locations on at least one of the outer frame 2 and the inner frame 3, like the foam portions 20 and non-foam portions 30, described later. The thick portions 4 may be provided only at the four corners of the outer frame 2. The thick portions 4 may also be provided in a portion of the inner frame 3. For example, the thick portions 4 may be provided only on the vertical bars 31 of the inner frame 3. The thick portions 4 may be provided only on portions of the outer frame 2 and the inner frame 3 that are subjected to a greater load than other portions when the LED module board M (see FIG. 3) is attached to the board mounting frame 1.

[0034] The four corners include, in the outer frame 2, the connection portion between the upper frame portion 21 and the left frame portion 23, the connection portion between the upper frame portion 21 and the right frame portion 24, the connection portion between the lower frame portion 22 and the left frame portion 23, and the connection portion between the lower frame portion 22 and the right frame portion 24. The four corners also include portions adjacent to these connection portions and portions that are subjected to a greater load than other portions of the outer frame 2 when the LED module board M is attached to the board mounting frame 1.

[0035] As shown in FIG. 2, the thick portion 4 has a foam layer 5, a non-foam layer 6, and a non-foam layer 7. The foam layer 5 is foam-molded and is also called a core layer. A large number of air bubbles are formed inside the foam layer 5. The non-foam layer 6 and the non-foam layer 7 are not foam-molded and are also called skin layers. The foam layer 5 is positioned between the non-foam layer 6, which is laminated in front of the foam layer 5, and the non-foam layer 7, which is laminated behind the foam layer 5, in the front-rear direction. In the present disclosure, the foam layer 5 is defined as a layer having a thickness of 1 cm in a longitudinal cross section of the board mounting frame 1 cut in the front-rear direction (plane B-F in FIG. 1). ２ The non-foamed layer 6 and the non-foamed layer 7 are regions in which the area of ​​the bubbles having a cell diameter of 5 μm or more accounts for 5% or more of the total area of ​​the non-foamed layer 6. In other words, the non-foamed layer 6 and the non-foamed layer 7 are regions in which the area of ​​the bubbles is less than 5%.

[0036] The expansion ratio of the thick-walled portion 4 can be 1.1 times or more and less than 3.0 times. If the expansion ratio is too low, the thickness T1 of the thick-walled portion 4 will be small, making it difficult to obtain a predetermined mechanical strength and also making it difficult to achieve weight reduction by increasing the density of the thick-walled portion 4. On the other hand, if the expansion ratio is too high, although the thickness T1 will be large, the density of the thick-walled portion 4 will tend to decrease, resulting in a decrease in mechanical strength. Therefore, from the perspective of achieving weight reduction while ensuring a predetermined mechanical strength in the outer frame 2, the lower limit of the expansion ratio of the thick-walled portion 4 is preferably 1.1 times or more, preferably 1.2 times or more, and more preferably 1.5 times or more. Furthermore, the upper limit of the expansion ratio of the thick-walled portion 4 is preferably less than 3.0 times, preferably 2.8 times or less, and more preferably 2.5 times or less. In other words, the expansion ratio of the thick portion 4 is preferably 1.1 times or more and less than 3.0 times, more preferably 1.2 times or more and 2.8 times or less, and even more preferably 1.5 times or more and 2.5 times or less.

[0037] In this way, by forming the foam layer 5 between the non-foam layer 6 and the non-foam layer 7 in at least a portion of the board mounting frame 1, the thickness of the board mounting frame 1 in the front-to-rear direction can be increased to ensure mechanical strength, and weight can be reduced by foam molding. Furthermore, as described above, the increased thickness of the board mounting frame 1 through foam molding suppresses warpage deformation after resin molding, and foam molding also suppresses the occurrence of sink marks. This improves the dimensional accuracy of the board mounting frame 1.

[0038] As shown in FIGS. 1 and 2 , the thick-walled portion 4 preferably has a thickness T1 of 7 mm or more in the front-to-rear direction. By making the thickness T1 of the thick-walled portion 4 7 mm or more, i.e., relatively large, not only can the board mounting frame 1 ensure a predetermined mechanical strength, but the increased rigidity can also suppress warpage. On the other hand, the thick-walled portion 4 preferably has a thickness T1 of 100 mm or less in the front-to-rear direction. In other words, if the thickness T1 of the thick-walled portion 4 is too large, the weight of the board mounting frame 1 increases, reducing the benefits of forming the board mounting frame 1 from a synthetic resin. Furthermore, if the thick-walled portion 4 is formed by typical injection molding, sink marks can easily occur, resulting in poor appearance. Furthermore, if the thickness T1 is increased by relatively increasing the foaming ratio of the thick-walled portion 4, the density of the thick-walled portion 4 decreases, making it difficult to ensure the predetermined mechanical strength of the board mounting frame 1. Therefore, from the viewpoint of suppressing the occurrence of warpage and sink marks while ensuring a predetermined mechanical strength, the lower limit of the thickness T1 of the thick-walled portion 4 in the front-to-rear direction should be 7 mm or more, preferably 10 mm or more, and more preferably 30 mm or more. The upper limit of the thickness T1 of the thick-walled portion 4 in the front-to-rear direction should be 100 mm or less, preferably 80 mm or less, and more preferably 60 mm or less. In other words, the thickness T1 of the thick-walled portion 4 should be 7 mm to 100 mm, preferably 10 mm to 80 mm, and more preferably 30 mm to 60 mm.

[0039] The foam layer 5 can have a thickness T2 that is 50% or more and less than 98% of the total thickness of the board mounting frame 1 in the front-to-rear direction at the thick-walled portion 4, i.e., the thickness T1 of the thick-walled portion 4. By performing foam molding so that the thickness T2 of the foam layer 5 is a predetermined ratio of the thickness T1 of the thick-walled portion 4, the occurrence of sink marks can be suppressed and the dimensional accuracy of the board mounting frame 1 can be improved. If the thickness T2 of the foam layer 5 is less than 50% of the thickness T1 of the thick-walled portion 4, it becomes difficult to suppress the occurrence of sink marks due to foam molding. That is, the greater the ratio of the thickness T2 of the foam layer 5 to the thickness T1 of the thick-walled portion 4, the more effectively sink marks can be suppressed, and the greater the thickness T1 of the thick-walled portion 4, the more effectively warpage can be suppressed. On the other hand, if the thickness T2 of the foam layer 5 is 98% or more of the thickness T1 of the thick-walled portion 4, it becomes difficult to achieve the required mechanical strength in the board mounting frame 1. Therefore, from the viewpoint of suppressing the occurrence of sink marks and obtaining a predetermined mechanical strength in the board mounting frame 1, the thickness T2 of the foam layer 5 is preferably 50% or more, preferably 60% or more, more preferably 70% or more, and less than 98%, preferably 95% or less, and more preferably 90% or less of the thickness T1 of the thick-walled portion 4. In other words, the thickness T2 of the foam layer 5 is preferably 50% or more and less than 98%, preferably 60% to 95%, and more preferably 70% to 90% of the thickness T1 of the thick-walled portion 4.

[0040] The average cell diameter of the bubbles contained in the foam layer 5 can be 5 μm or more and less than 300 μm. If the average cell diameter of the bubbles is too small, it becomes difficult to reduce the weight of the board mounting frame 1. If the average cell diameter of the bubbles is too large, it becomes difficult to ensure the mechanical strength of the board mounting frame 1. From this perspective, the average cell diameter of the bubbles contained in the foam layer 5 is preferably less than 300 μm, more preferably 200 μm or less, and even more preferably 100 μm or less.

[0041] As shown in FIG. 1 , the board mounting frame 1 can have a foamed section 20 and a non-foamed section 30. The foamed section 20 is a foam-molded portion of the board mounting frame 1. The thick section 4 described above is a foam-molded portion, and therefore corresponds to the foamed section 20. In the illustrated board mounting frame 1, the foamed section 20 includes the foamed layer 5 indicated by the dashed line and the non-foamed layers 6 and 7 laminated in the front-to-rear direction of the foamed layer 5. The non-foamed section 30 is a portion that is not foam-molded. It can also be said that the non-foamed section 30 is a portion of the board mounting frame 1 other than the foamed section 20. In this embodiment, the foamed section 20 is formed at the corners (four corners) of the outer frame 2, between the mating sections 9 or mated sections 10 on each side of the outer frame 2, and on the inner frame 3. In this manner, the board mounting frame 1 may include the foamed section 20 and the non-foamed section 30. The entire board mounting frame 1 may also be formed from the foamed section 20. The foam sections 20 may be formed on the outer frame 2 or on the inner frame 3. The number and size of the foam sections 20 can be changed depending on the size of the board mounting frame 1.

[0042] The mounting surface 8 is the surface of the board mounting frame 1 for mounting an LED module board M (see FIG. 3). As shown in FIG. 1, the mounting surface 8 can be considered the surface located in front of the board mounting frame 1. From the perspective of mounting the LED module board M, the mounting surface 8 is preferably as flat as possible, i.e., has as little flatness as possible. If the flatness of the mounting surface 8 is too great, misalignment may occur between the LED module boards M mounted on each board mounting frame 1 when the board mounting frames 1 are connected, potentially reducing the visibility of the LED vision. Therefore, the flatness of the mounting surface 8 is preferably 0.3 mm or less, preferably 0.2 mm or less, and more preferably 0.1 mm or less. The flatness can be measured, for example, using a 3D scanner (Keyence Corporation, model number "V-700").

[0043] The resin material for the board mounting frame 1 is not particularly limited, but the following resins are preferred from the viewpoints of ensuring mechanical strength, durability, and low water absorption. Thermoplastic resins are preferred for the board mounting frame 1 from the viewpoint of moldability into complex shapes. Of the crystalline and amorphous thermoplastic resins, non-crystalline resins are particularly preferred from the viewpoint of improving dimensional accuracy. Examples of the crystalline resin include PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), HIPS (high impact PS), and liquid crystal polymer (LCP). Examples of the amorphous resin include PC (polycarbonate), m-PPE (modified polyphenylene ether), PPO (polyphenylene oxide), PPE (polyphenylene ether), PSU (polysulfone), PPSU (polyphenylsulfone), and PEI (polyetherimide). Furthermore, alloys or copolymers of these resins may also be used as the resin material for the board mounting frame 1. From the viewpoints of cost reduction and improved moldability or low-temperature impact resistance (strength), polycarbonate is preferably used as the resin material for board mounting frame 1. Furthermore, from the viewpoint of further improving weather resistance, chemical resistance, or low-temperature impact resistance, the resin material for board mounting frame 1 may be a copolymer of polycarbonate and silicone, or an alloy or copolymer of PBT and a specified resin.

[0044] The resin material of the board mounting frame 1 may contain a filler to improve mechanical strength, suppress thermal expansion, and reduce water absorption. Examples of the filler include carbon fiber, glass fiber, talc, and mineral. However, glass fiber is preferred for cost reduction, and flat glass fiber may be used for the filler to suppress warpage and reduce the linear expansion coefficient. When the resin material of the board mounting frame 1 contains a fibrous filler such as carbon fiber, glass fiber, or flat glass fiber, the fibrous filler is oriented along the flow direction of the molten resin during molding of the board mounting frame 1. This can easily cause anisotropy in the strength and linear expansion coefficient of the board mounting frame 1 in the flow direction of the molten resin and in directions perpendicular to the flow direction. This anisotropy can be alleviated by including a flat filler in the resin material or by molding the board mounting frame 1 using core-back foaming, as described below.

[0045] Furthermore, when a load of 30 kg is applied to the center of the upper end surface of the upper frame portion 21 of the rectangular frame shape of the board mounting frame 1, the deformation amount of the upper frame portion 21 may be 0.4 mm or less. By foam-molding the foam portion 20 (thick portion 4) as described above, the deformation amount of the upper frame portion 21 can be reduced. This results in a board mounting frame 1 that has excellent dimensional accuracy and can be lightweight while maintaining a predetermined mechanical strength. The deformation amount of the upper frame portion 21 should be 0.4 mm or less, preferably 0.2 mm or less, and more preferably 0.1 mm or less.

[0046] [Method of Manufacturing Board Mounting Frame] Next, a method of manufacturing the board mounting frame 1 will be described.

[0047] The board mounting frame 1 can be formed, for example, by a core-back molding method from the viewpoint of forming a foam layer 5 with a uniform thickness. The core-back molding method is a method of foam-molding a resin material by injecting molten resin containing a foaming agent into a mold and then moving a portion of the mold outward to expand the volume within the mold. This method allows the thick-walled portion 4 (foamed portion 20) to be formed. On the other hand, the non-foamed portion 30 is molded without moving a portion of the mold. This method allows the non-foamed portion 30 to be formed. That is, in the manufacturing method of the board mounting frame 1, while the mold is filled with resin material, the foamed portion 20 can be formed in the portion where the portion of the mold is moved, and the non-foamed portion 30 can be formed in the portion where the mold is not moved. In this embodiment, the thick-walled portion 4 (foamed portion 20) is foam-molded by moving a portion of the mold backward. The foaming agent can be, for example, a physical foaming agent. The use of a physical foaming agent makes it easier to foam high-strength or high-heat-resistant resin materials containing fillers, thereby reducing environmental impact. Examples of molding methods that use the physical foaming agent include a high-pressure molding method using a supercritical fluid (MuCell (registered trademark)) and a low-pressure molding method using a low-pressure gas without using a pressure booster. However, the manufacturing method of board mounting frame 1 is not limited to these, and any other method can be used as long as it can form thick portion 4 (foam portion 20) including foam layer 5 so as to reduce the weight of board mounting frame 1 while ensuring a predetermined mechanical strength.

[0048] [Frame Joint] Next, the frame joint 100 formed by joining the above-described board mounting frames 1 together will be specifically described with reference to FIGS. 3 to 7. FIG.

[0049] As shown in FIG. 3, the frame assembly 100 is formed by connecting one (lower in the figure) board mounting frame 1 with the other (upper in the figure) board mounting frame 1 .

[0050] One of the board mounting frames 1 has fitting portions 9 on its outer peripheral surface (in this embodiment, for example, the upper end surface of the upper frame portion 21 and the right end surface of the right frame portion 24 (see FIG. 1 )). In this embodiment, the fitting portions 9 are convex portions that protrude upward from the upper end surface of the upper frame portion 21 and to the right from the right end surface of the right frame portion 24, and multiple fitting portions 9 are provided on each of the upper end surface of the upper frame portion 21 and the right end surface of the right frame portion 24.

[0051] 5, the protrusion of the fitting portion 9 has a cylindrical base end portion 91 extending from the outer circumferential surface and a truncated cone-shaped tip end portion 92 extending from the base end portion 91. In other words, the protrusion has a tapered shape from the upper end of the base end portion 91 to the tip of the tip end portion 92.

[0052] The other board mounting frame 1 has mating portions 10 on its outer peripheral surface (the lower end surface of the lower frame portion 22 and the left end surface of the left frame portion 23) that can be mated with the mating portions 9. In this embodiment, the mating portions 10 are recesses that can fit over the protrusions of the mating portions 9, and multiple mating portions 10 are provided on the lower end surface of the lower frame portion 22 and the left end surface of the left frame portion 23 to correspond to the mating portions 9.

[0053] One board mounting frame 1 and the other board mounting frame 1 can be easily connected by fitting the fitting portion 9 into the fitted portion 10. Furthermore, because the tip 92 of the convex portion of the fitting portion 9 has a tapered shape, it is easier to position the fitting portion 9 relative to the fitted portion 10 when starting to fit it into the fitted portion 10, improving the efficiency of the work involved in connecting the board mounting frames 1 to each other.

[0054] The size or shape of the fitting portion 9 and the fitted portion 10 corresponding to the fitting portion 9 are not particularly limited, and may be cylindrical, polygonal prism, conical, or the like. 3 and 4 show a configuration in which the fitting portion 9 is formed on the upper end surface of the upper frame portion 21 of one board mounting frame 1, and the fitted portion 10 is formed on the lower end surface of the lower frame portion of the other board mounting frame 1. However, from the perspective of improving the efficiency of the process of connecting board mounting frames 1, the fitted portion 10 may be formed on the upper end surface of the upper frame portion 21 of one board mounting frame 1, and the fitting portion 9 may be formed on the lower end surface of the lower frame portion 22 of the other board mounting frame 1.

[0055] 3 and 4, each of the first and second board mounting frames 1 has a mating portion 9 on the top end surface of the upper frame portion 21 and the right end surface of the right frame portion 24, and a mated portion 10 on the bottom end surface of the lower frame portion 22 and the left end surface of the left frame portion 23. This allows multiple board mounting frames 1 to be connected in at least one of the vertical and horizontal directions.

[0056] The mounting surface 8 of the LED module board M on one board mounting frame 1 and the mounting surface 8 of the LED module board M on the other board mounting frame 1 can be made flush with each other when the one board mounting frame 1 and the other board mounting frame 1 are connected. This makes it possible to prevent misalignment between the LED module boards M attached to each board mounting frame 1 when the board mounting frames 1 are connected to each other. This ensures the visibility of the LED vision.

[0057] The process of connecting the board mounting frames 1 in the left-right direction is basically the same as that of connecting them in the up-down direction, so a detailed explanation will be omitted.

[0058] 4 and 5, the frame assembly 100 may have a movement restricting portion 101. In this embodiment, the movement restricting portion 101 has a convex restricting portion 101a and a concave restricting portion 101b.

[0059] The convex stopping portion 101a is formed on the upper end surface of the upper frame portion 21 of one board mounting frame 1, i.e., on the joint surface that connects to the other board mounting frame 1. The convex stopping portion 101a is formed by arranging small, quadrangular pyramidal protrusions that are smaller than the above-mentioned fitting portion 9 in a continuous, planar manner in the front-to-rear and left-to-right directions. The height of the convex stopping portion 101a protruding from the upper end surface of the upper frame portion 21 of one board mounting frame 1 is not particularly limited, but can be, for example, 0.5 mm to 5 mm. Furthermore, the shape of each small protrusion in the convex stopping portion 101a is not limited to a quadrangular pyramid shape, and may be a polygonal pyramid shape other than a quadrangular pyramid shape, a cone shape, a hemisphere shape, or the like.

[0060] The recessed stopping portion 101b is formed on the lower end surface of the lower frame portion 22 of the other board mounting frame 1, i.e., on the joining surface that connects to one board mounting frame 1. The recessed stopping portion 101b is formed by arranging small recesses that are smaller than the above-mentioned mating portion 10 in a continuous line in the front-rear and left-right directions in a planar manner so as to correspond to the small protrusions of the protruding stopping portion 101a.

[0061] When one board mounting frame 1 and the other board mounting frame 1 are connected, the convex restraining portion 101a and the concave restraining portion 101b fit together to prevent relative movement in the front-to-back and left-to-right directions between the one board mounting frame 1 and the other board mounting frame 1. Therefore, by providing the movement restraining portion 101, relative movement in the front-to-back and left-to-right directions between the one board mounting frame 1 and the other board mounting frame 1 can be further prevented.

[0062] The movement restricting portions 101 may be provided at multiple locations on the joining surface of one board mounting frame 1 and the joining surface of the other board mounting frame 1. For example, as shown in Figures 4 and 5, the movement restricting portions 101 are provided at multiple locations on the joining surface of one board mounting frame 1 and the joining surface of the other board mounting frame 1 so as to avoid the mating portions 9 and mated portions 10 that are mated.

[0063] Note that the movement restraint portion 101 is not limited to this configuration, and may be formed, for example, by applying a fine embossing process to either the joining surface of one board mounting frame 1 or the joining surface of the other board mounting frame 1, as long as it does not affect the flatness of the joining surfaces of the one board mounting frame 1 and the other board mounting frame 1. Alternatively, one board mounting frame 1 may be provided with a concave restraint portion 101b, and the other board mounting frame 1 may be provided with a convex restraint portion 101a. Alternatively, the movement restraint portion 101 may be provided on the left end face or the right end face of the board mounting frame 1.

[0064] By providing the movement restraints 101 on one board mounting frame 1 and the other board mounting frame 1 in this way, it is possible to restrain left-right and front-back movement between the board mounting frames 1. As a result, even if the LED module boards M attached to each board mounting frame 1 generate heat, causing one or the other board mounting frame 1 to expand, it is possible to prevent misalignment or gaps from occurring between adjacent board mounting frames 1. This ensures the visibility of the LED vision.

[0065] (Variant example) As shown in Figures 6 and 7, the mating portion 190 and the mated portion 110 may be configured to prevent relative movement in the vertical direction between the board mounting frames 1 by sliding one of the mating portion 190 and the mated portion 110 in the front-to-back direction relative to the other and fitting them together, thereby connecting one board mounting frame 1 to the other board mounting frame 1.

[0066] In this modification, the mating portion 190 is a wedge-shaped protrusion. That is, the protrusion of the mating portion 190 has an inverted trapezoidal shape when viewed from the front or rear, and its width gradually increases toward the top. The mating portion 190 is provided so as to protrude from the upper end surface of the other board mounting frame 1.

[0067] The mating portion 110 is a recess into which the mating portion 190 can be slid from the front or rear. The recess of the mating portion 110 has an inverted trapezoidal shape when viewed from the front or rear, and its width gradually increases toward the top. The mating portion 110 is recessed into the lower end surface of one board mounting frame 1. That is, the mating portion 110 is recessed on the mating surface of the other board mounting frame 1 so that the mating portion 190 is mated with and fixed vertically relative to the mating portion 110. In this modification, the mating portion 190 is mated with the mating portion 110 by sliding the other board mounting frame 1 from rear to front relative to the one board mounting frame 1. This allows the one board mounting frame 1 and the other board mounting frame 1 to be connected and prevents relative vertical movement between the one board mounting frame 1 and the other board mounting frame 1. As a result, even if one or the other of the board mounting frames 1 expands due to heat, it is possible to prevent gaps from occurring between the board mounting frames 1. Therefore, visibility of the LED vision can be ensured.

[0068] In this modification, as shown in FIG. 7 , the mating portion 190 has a tapered shape that tapers toward the rear. This facilitates positioning of the first board mounting frame 1 relative to the second board mounting frame 1 when starting to engage the mating portion 190 with the mated portion 110, improving the efficiency of the process of connecting the first board mounting frame 1 to the second board mounting frame 1. The mating portion 190 also has a stopper 93 extending in the left-right direction on its front side. This prevents the second board mounting frame 1 from moving forward relative to the first board mounting frame 1. A guide may be provided to facilitate the mating of the mating portion 190 and the mated portion 110. Once the first board mounting frame 1 and the second board mounting frame 1 are connected, a removable fastener may be attached to secure the rear of the first board mounting frame 1 to the rear of the second board mounting frame 1. This also makes it possible to prevent the one board mounting frame 1 and the other board mounting frame 1 from moving relatively backward.

[0069] The shapes of the mating portion and the mated portion are not limited to the above configuration and may be other shapes as long as they can prevent relative vertical movement between the first board mounting frame 1 and the second board mounting frame 1. For example, the frame portions of the first board mounting frame 1 and the second board mounting frame 1 may each have through holes as mating portions, and pins as mating portions may be inserted through these through holes to connect the first board mounting frame 1 and the second board mounting frame 1. In this case, it is preferable to provide a retaining member to prevent the pin from coming out. The pin may be, for example, a bolt. In this case, the retaining member may be a nut. The retaining member may have any configuration as long as it is capable of preventing the pin from coming out. The mating portion and the mated portion may be formed on the left frame portion 23 and the right frame portion 24.

[0070] The shapes of the fitting portions 9, 190, fitted portions 10, 110, and movement restricting portion 101 as described above can be easily formed because the board mounting frame 1 is made of resin. In particular, the movement restricting portion 101, which has a fine shape, can be easily molded from resin.

[0071] With regard to the frame assembly 100 described above, it is preferable that the gap formed between the upper end surface of the upper frame portion 21 of one board mounting frame 1 (i.e., the joint surface with the other board mounting frame 1) and the lower end surface of the lower frame portion 22 of the other board mounting frame 1 (i.e., the joint surface with the one board mounting frame 1) be as small as possible in the temperature range of -30°C to 60°C. This gap should be 0.3 mm or less, and preferably 0.2 mm or less. In an environment where the LED vision is used or where the LED module boards M are generating heat, reducing the gap between the connected board mounting frames 1 can reduce the gap between the LED module boards M. This ensures the visibility of the LED vision.

[0072] [LED Vision] Next, an LED vision 1000 in which an LED module board M is attached to the above-described board mounting frame 1 will be described with reference to Fig. 8. Fig. 8 is a diagram schematically illustrating how the LED vision 1000 is configured by attaching the LED module board M to the board mounting frame 1.

[0073] Referring to FIG. 8 , the LED vision 1000 includes a board mounting frame 1 and an LED module board M. The board mounting frame 1 may be connected to other board mounting frames 1 to form the frame assembly 100 described above. In this case, the LED vision 1000 includes the frame assembly 100 and multiple LED module boards M. By using the board mounting frame 1 having the configuration of this embodiment, a pair of adjacent board mounting frames 1 can be easily connected. This makes it easy to assemble the LED vision 1000. Furthermore, because the board mounting frame 1 that supports the LED module boards M is used, it is possible to achieve a lightweight LED vision while maintaining mechanical strength.

[0074] <Embodiment 2> Figure 9 is a perspective view showing the schematic configuration of a board mounting frame 201 according to embodiment 2. Figure 10 is a cross-sectional view taken along line X-X in Figure 9. Referring to Figures 9 and 10, board mounting frame 201 differs from board mounting frame 1 of embodiment 1 in that it has a plate-shaped portion 233. In the following, components similar to those of embodiment 1 are given the same reference numerals and their description will be omitted, and only components different from embodiment 1 will be described.

[0075] The board mounting frame 201 has an outer frame 202 and an inner frame 203. The board mounting frame 201 also has a foam layer 205, a non-foam layer 206 (first non-foam layer), a non-foam layer 207 (second non-foam layer), and a mounting surface 208. The board mounting frame 201 may have a thick portion, similar to the board mounting frame 1 of embodiment 1. In this case, the foam layer 205, the non-foam layer 206, and the non-foam layer 207 may be provided only on the thick portion.

[0076] The outer frame 202 has a rectangular frame shape including an upper frame portion 221, a lower frame portion 222, a left frame portion 223, and a right frame portion 224. Although not shown, the outer frame 202 has mating portions and mated portions on its outer periphery for connecting to other board mounting frames 201. The shape of the outer frame 202 is not limited to a rectangular frame shape and is not particularly limited as long as it can be connected to other board mounting frames 201 with as little gap as possible. Furthermore, the dimension of one side of the rectangular outer frame 202, i.e., the length of each of the upper frame portion 221, lower frame portion 222, left frame portion 223, and right frame portion 224, is not particularly limited either.

[0077] The inner frame 203 is formed to connect opposing sides or adjacent sides of the outer frame 202. In this embodiment, referring to Fig. 9, the inner frame 203 has a vertical beam 231 located in the center of the outer frame 202 in the left-right direction and connecting the upper frame portion 221 and the lower frame portion 222, a horizontal beam 232 located in the center of the outer frame 202 in the up-down direction and connecting the left frame portion 223 and the right frame portion 224, and a plate-like portion 233 connected to the outer frame 202, the vertical beam 231, and the horizontal beam 232.

[0078] In the present embodiment, the plate-shaped portion 233 is located rearward with respect to the space surrounded by the outer frame 202 and the vertical and horizontal beams 231 and 232. The plate-shaped portion 233 may be located at any position in the front-to-rear direction relative to the outer frame 202, the vertical and horizontal beams 231 and 232, as long as it is connected to the outer frame 202, the vertical and horizontal beams 231 and 232. The plate-shaped portion 233 may be integrated with the outer frame 202, the vertical and horizontal beams 231 and 232, or may be a separate member from the outer frame 202, the vertical and horizontal beams 231 and 232. The plate-shaped portion 233 may be connected to at least two of the upper frame portion 221, the lower frame portion 222, the left frame portion 223 and the right frame portion 224 of the outer frame 202.

[0079] The inner frame 203 has the plate-like portion 233 as described above, which can improve the rigidity of the inner frame 203. Therefore, the mechanical strength of the board mounting frame 201 can be improved.

[0080] The inner frame 203 may have various shapes, such as a lattice pattern or a diagonal lattice pattern. The inner frame 203 may have a plurality of vertical bars 231 and a plurality of horizontal bars 232. The vertical bars 231 may be located at a position other than the center in the left-right direction of the outer frame 202. The horizontal bars 232 may be located at a position other than the center in the up-down direction of the outer frame 202.

[0081] The foam layer 205 is positioned in the front-to-rear direction between a non-foam layer 206 that is laminated in front of the foam layer 205 and a non-foam layer 207 that is laminated behind the foam layer 205. The configurations of the foam layer 205, the non-foam layer 206, and the non-foam layer 207 are similar to those of the foam layer 5, the non-foam layer 6, and the non-foam layer 7 in the first embodiment, and therefore detailed description thereof will be omitted.

[0082] 9 illustrates an example of the configuration of the board mounting frame 201 in which the foam layer 205 is provided over the entire outer frame 202 and the inner frame 203. However, the foam layer 205 may be provided only on a portion of the board mounting frame 201, as in the first embodiment. The foam layer 205 may be provided only on a portion of the outer frame 202 that is subjected to a relatively large load when the LED module board is attached to the board mounting frame 201. The foam layer 205 may be provided, for example, on the corners (four corners) of the rectangular outer frame 202, or on the vertical bars 231 of the inner frame 203. As in the first embodiment, when the board mounting frame 201 has a mating portion or a mated portion, the foam layer 205 is preferably provided so as to avoid the mating portion or the mated portion.

[0083] The mounting surface 208 is a surface of the board mounting frame 201 for mounting the LED module board. The mounting surface 208 may be said to be a surface located in front of the board mounting frame 201. The configuration of the mounting surface 208 is also similar to that of the mounting surface 8 in the first embodiment, and therefore a detailed description thereof will be omitted.

[0084] As described above, the board mounting frame 201 of this embodiment, which has the plate-shaped portion 233, has higher mechanical strength than the board mounting frame 1 of Embodiment 1. Therefore, the board mounting frame 201 can more reliably support the LED module board for a long period of time.

[0085] The method for manufacturing the board mounting frame 201 is the same as the method for manufacturing the board mounting frame 1 of embodiment 1. Therefore, detailed explanation of the method for manufacturing the board mounting frame 201 will be omitted.

[0086] By connecting board mounting frames 201 having the above-described configuration together, a frame assembly is formed, similar to the board mounting frame 1 of embodiment 1. The frame assembly formed by connecting board mounting frames 201 together is the same as embodiment 1 except that board mounting frame 201 is used instead of board mounting frame 1. Therefore, a detailed description of the frame assembly will be omitted. Note that the frame assembly formed by connecting board mounting frames 201 together may also have a movement restricting portion 101, similar to the frame assembly 100 of embodiment 1.

[0087] The board mounting frame 1, 201, the frame assembly 100, and the LED vision 1000 include a foam layer that is foam-molded. This allows for a reduction in the amount of resin used in the board mounting frame 1, 201, the frame assembly 100, and the LED vision 1000. As a result, the board mounting frame 1, 201, the frame assembly 100, and the LED vision 1000 improve resource utilization efficiency, reduce transportation burden, reduce energy consumption, and reduce CO ２This can contribute to reducing emissions. By providing the board mounting frame 1, 201, frame assembly 100, and LED vision 1000 to society, it is possible to contribute to achieving Goal 7 (Affordable and Clean Energy), Goal 9 (Industry, Innovation and Infrastructure), and Goal 11 (Sustainable Cities and Villages) of the 17 Sustainable Development Goals (SDGs) established by the United Nations. Furthermore, because the board mounting frame 1 and frame assembly 100 according to this embodiment can be melted and reused, it can contribute to achieving Goal 12 (Responsible Consumption and Production).

[0088] Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0089] [Examples] Based on the conditions shown in Table 1, specimens of Examples 1 to 5 and Comparative Examples 1 and 2 as shown in FIG. 1 were prepared, and tests were conducted to measure the flatness of the mounting surface, the amount of deformation of the upper frame when a load was applied, and the amount of gap when the board mounting frames were connected together.

[0090]

[0091] Example 1 The specimen for Example 1 was the board mounting frame shown in FIG. 1 , with one side of the outer frame 500 mm long, square in shape when viewed from the front, and the maximum thickness of the thick wall portion in the front-to-rear direction 40 mm. The specimen for Example 1 was molded by a core-back molding method using the low-pressure gas physical foam molding method described in Patent Document 6,136,038. The resin material for the specimen for Example 1 was a 40% glass fiber reinforced polycarbonate (LUPOY GN2403FT, manufactured by LG Chemical Corporation).

[0092] The process for preparing the specimen of Example 1 will now be described in detail. First, the resin material in the cylinder was plasticized and melted using a screw with screw flights suitable for promoting a starvation state. Then, nitrogen gas, which had been extracted from a nitrogen cylinder by reducing the pressure to 8 MPa using a pressure reducing valve, was injected into the starvation zone. The nitrogen-infused molten resin was then injected into a mold, and core-back foaming was performed. Core-back foaming is a foam molding method in which a resin material is injected into a pre-narrowed space in the mold, pressure is applied to temporarily eliminate air bubbles, and then part of the mold is moved outward to expand the space within the mold, thereby foaming the resin by the expanded volume. Core-back foaming is suitable for uniformly molding a foam layer with a relatively high expansion ratio inside a resin molded body. However, there are often restrictions on the shape of the molded resin molded body. Therefore, in the specimen of Example 1, part of the movable mold was locked to the fixed mold with a magnet at a part of the outer frame, i.e., the part forming the mating portion and the mated portion. Thereafter, only the movable core plate, which was in close contact with the movable mold and guided by the solid lubricant, was opened in response to the opening of the mold. In this manner, a specimen of Example 1 having a foamed portion and a non-foamed portion was produced.

[0093] Furthermore, since the outer peripheral surface of the board mounting frame, i.e., the bonding surface with respect to other board mounting frames, is perpendicular to the mounting surface of the LED module board, it is not possible to form the draft angle required for releasing the board mounting frame backward (towards the core back) after molding. Therefore, the board mounting frame was released by sliding the outer peripheral surface of the board mounting frame against the inner surface of the mold.

[0094] In the specimen of Example 1, the thickness of the thick portion was adjusted to 40 mm by core-back foaming from 25 mm to 15 mm. In other words, the expansion ratio of the thick portion was 1.6 times (a 37% density reduction). The front-to-rear thickness of the foam layer was approximately 34-36 mm, and the thicknesses of the first non-foamed layer and the second non-foamed layer were each 2-3 mm. In other words, the thickness of the foam layer was 80-90% of the total thickness of the thick portion. The flatness of the mounting surface was 0.15 mm. A jig was attached to the center of the upper frame of the specimen, and a total load of 30 kg was applied. The deformation of the center of the upper frame was 0.1 mm, as measured with a dial gauge.

[0095] Furthermore, the test pieces of Example 1 were joined together, restrained at their upper ends, and left in thermostatic chambers at 60°C and -30°C for one hour, then removed. The gap formed between the two test pieces was measured under a microscope and found to be 0.2 mm. The mass of the test piece of Example 1 was 25% less than that of an equivalent aluminum frame.

[0096] (Example 2) The specimen of Example 2 was manufactured using the same mold as Example 1, and core-back foaming was performed from a thickness of 3.5 mm to 4 mm, resulting in a thickness of 7.5 mm in the thick portion. The thickness of the specimen of Example 2 was smaller than that of Example 1. Therefore, in the specimen of Example 2, the thickness of the non-foamed layer was relatively large, and the thickness of the foamed layer was 60 to 68% of the total thickness of the thick portion. As a result, the flatness, deformation amount, and gap amount of the specimen of Example 2 were slightly worse than those of the specimen of Example 1.

[0097] (Example 3) The basic conditions of the specimens of Example 3 were the same as those of Example 1, but the specimens were fixed together with bolts without providing a mating portion and a mated portion. When the specimens of Example 3 and Example 1 were compared, there was no difference in the flatness and deformation amount between the two, but the specimen of Example 3 had a slightly worse gap compared to the specimen of Example 1. In this way, it was found that the gap amount was reduced by mating and connecting the mating portion and the mated portion as in Example 1.

[0098] (Example 4) The basic conditions for the specimen of Example 4 were the same as those for Example 1, but unlike Example 1, a movement restriction portion as shown in Figure 5 was formed. Note that in the specimen of Example 4, a plurality of small convex portions with a height of 2 mm and small concave portions with a depth of 2 mm were arranged to form the movement restriction portion. As a result, the specimen of Example 4 was able to have a smaller gap amount than Example 1.

[0099] (Example 5) The basic conditions of the specimen of Example 5 were the same as those of Example 1, but the fitting portion and the fitted portion were formed to have a wedge shape as shown in Figures 6 and 7. The specimen of Example 5 was able to significantly reduce the gap amount compared to the other examples.

[0100] Example 6: In the specimen of Example 6, similar to Example 1, the thickness of the thick portion was adjusted to 40 mm by core-back foaming from 25 mm to 15 mm. However, in the specimen of Example 6, the expansion ratio of the thick portion was 1.3 times, i.e., the ratio of the foam layer thickness to the total thickness of the thick portion was 35 to 45%. The flatness of the mounting surface was 0.40 mm, the deformation under load was 0.12 mm, and the gap was 0.4 mm. In the specimen of Example 6, the thickness ratio of the foam layer 5 was less than 50%. Therefore, although the flatness and gap of the specimen of Example 6 were slightly inferior to those of Example 1, the deformation under load of the specimen of Example 6 was approximately equivalent to those of Examples 1 to 5.

[0101] (Example 7) The specimen of Example 7 was manufactured using the same mold as in Example 1, with a core-back foaming process from a thickness of 3 mm to a thickness of 3 mm, resulting in a thick-walled portion of 6.0 mm. Compared to Comparative Example 1 (described later), the specimen of Example 7 is lighter due to the foamed layer. Furthermore, despite its smaller thickness compared to Comparative Example 1 (described later), the specimen of Example 7 was able to reduce the gap, although its deformation under load was slightly inferior. Therefore, it can be said that the specimen of Example 7 was able to achieve a reduced weight while maintaining a predetermined mechanical strength. Furthermore, compared to Example 2 (in which the thick-walled portion had a thickness of 7.5 mm), the specimen of Example 7 was slightly inferior in terms of flatness, deformation under load, and gap. Therefore, it was found that in order to more effectively ensure the mechanical strength of the board mounting frame while reducing flatness and thereby ensuring the visibility of the LED vision, it is best to set the thickness of the thick-walled portion to 7 mm or more, preferably 40 mm or more.

[0102] (Comparative Example 1) The specimen of Comparative Example 1 was formed by normal injection molding without core-back foaming, and the thickness of the thick-walled portion was 40 mm, the same as in Example 1. The specimen of Comparative Example 2 suffered from warpage deformation after molding, and also had large sink marks. As a result, the flatness significantly increased, and the visibility of the LED vision screen deteriorated.

[0103] 1,201 Board mounting frame, 2,202 Outer frame, 21,221 Upper frame portion, 22,222 Lower frame portion, 23,223 Left frame portion, 24,224 Right frame portion, 3,203 Inner frame, 31,231 Vertical beam, 32,232 Horizontal beam, 233 Plate-shaped portion, 4 Thick portion, 5,205 Foam layer, 6,206 Non-foam layer, 7,207 Non-foam layer, 8,208 Mounting surface, 9,190 Fitting portion, 91 Base end portion, 92 Tip portion, 93 Stopper, 10,110 Fitted portion, 100 Frame joint body, 101 Movement restraining portion, 101a Convex restraining portion, 101b Concave restraining portion, 1000 LED vision, M LED module board, T1 Thickness of thick part, T2 Thickness of foam layer

Claims

1. A board mounting frame to which an LED module board for an LED vision is attached, the board mounting frame being made of synthetic resin, and at least a portion of the board mounting frame including a foam layer, a first non-foam layer laminated in front of the foam layer, and a second non-foam layer laminated behind the foam layer.

2. A board mounting frame as claimed in claim 1, wherein the board mounting frame has an upper frame portion, a lower frame portion, a left frame portion and a right frame portion, and is formed in a rectangular frame shape by these frame portions, and at least four corners of the board mounting frame include the foam layer, the first non-foam layer and the second non-foam layer.

3. A board mounting frame as claimed in claim 2, further comprising a vertical bar connecting the upper frame portion and the lower frame portion, the vertical bar including the foam layer, the first non-foam layer and the second non-foam layer.

4. A board mounting frame as claimed in claim 2, further comprising a plate-like portion connected to at least two of the upper frame portion, the lower frame portion, the left frame portion and the right frame portion, the plate-like portion including the foam layer, the first non-foam layer and the second non-foam layer.

5. A board mounting frame as claimed in claim 1, wherein the board mounting frame includes the foam layer, the first non-foam layer and the second non-foam layer, and has a thick section having a thickness of 7 mm or more in the front-to-back direction, and the foam layer has a thickness in the thick section that is 50% or more but less than 98% of the total thickness of the board mounting frame in the front-to-back direction.

6. A board mounting frame according to claim 1, wherein the mounting surface of the LED module board located in front of the board mounting frame has a flatness of 0.3 mm or less.

7. A board mounting frame according to claim 1, wherein the synthetic resin contains a filler.

8. A board mounting frame according to claim 1, wherein the synthetic resin includes polycarbonate.

9. A circuit board mounting frame as claimed in claim 1, wherein the circuit board mounting frame has a rectangular frame shape including an upper frame portion, a lower frame portion, a left frame portion and a right frame portion, and when a load of 30 kg is applied to the centre of the upper end face of the upper frame portion, the deformation of the upper frame portion is 0.4 mm or less.

10. A frame joint for connecting a plurality of adjacent board mounting frames according to any one of claims 1 to 9, wherein a pair of adjacent board mounting frames are connected so that their respective joint surfaces face each other, one of the pair of board mounting frames has a mating portion on the joint surface facing the other board mounting frame, and the other board mounting frame has a mated portion into which the mating portion can be mated, and the pair of board mounting frames are connected by mating the mating portion with the mated portion.

11. A frame assembly as described in claim 10, wherein the mounting surface on which the LED module is mounted in the one board mounting frame and the mounting surface on which the LED module is mounted in the other board mounting frame are flush with each other when the one board mounting frame and the other board mounting frame are connected.

12. A frame joint as claimed in claim 10, wherein at least one of the joint surfaces of the one board mounting frame and the other board mounting frame has a movement restricting portion for restricting movement of the one board mounting frame and the other board mounting frame in the forward / backward and left / right directions when they are connected.

13. A frame joint as described in claim 10, wherein the engaging portion and the engaged portion are formed so that one of the engaging portion and the engaged portion slides relative to one another in the front-to-rear direction to engage with each other, and so that when the one board mounting frame and the other board mounting frame are connected, they are prevented from moving in the up-down and left-right directions.

14. A frame joint as claimed in claim 13, wherein the mating portion is a protrusion that protrudes from the mating surface of the other board mounting frame, and the mated portion is a recess that is recessed on the mating surface of the one board mounting frame so that the mating portion is mated with and fixed in the vertical direction relative to the mated portion.

15. A frame assembly as set forth in claim 10, wherein the gap formed between the joint surface of one board mounting frame and the joint surface of the other board mounting frame is 0.3 mm or less in the temperature range of -30°C to 60°C.

16. An LED vision device comprising: a board mounting frame according to any one of claims 1 to 9; and an LED module board mounted on the board mounting frame.

Images