LED display device

Abstract

An LED display device (1) comprises: an LED display layer (10) that has surfaces (10A, 10B) positioned on mutually opposite sides in the thickness direction, the LED display layer (10) including a plurality of LED elements (11) disposed along one of the surfaces; a photovoltaic layer (20) that is disposed side by side with one of the surfaces of the LED display layer (10); and a battery unit (30) that is electrically connected to the LED display layer (10) and the photovoltaic layer (20), the battery unit (30) including a plurality of batteries (31). Power generated in the photovoltaic layer (20) is stored in the battery unit (30), and the LED display layer (10) is driven by the power stored in the battery unit (30).

Description

LED display device

[0001] The present disclosure relates to LED display devices.

[0002] A display device including a display screen and a rechargeable battery is known (see, for example, International Publication No. 2019 / 130025 (Patent Document 1)). With such a display device, the battery is charged in advance and power is supplied from the battery to the display screen, so that the display device can be operated even in a location far from a power source.

[0003] International Publication No. 2019 / 130025

[0004] However, the above-mentioned display devices have a problem in that the operating time of the display is limited by the battery capacity, making it difficult to operate for a long time. The present disclosure addresses this problem, and one of its objectives is to provide an LED display device that enables long-term operation.

[0005] An LED display device according to the present disclosure includes an LED display layer having surfaces opposite to each other in a thickness direction and including a plurality of LED elements arranged along one of the surfaces, a photovoltaic cell layer arranged alongside one of the surfaces of the LED display layer, and a battery unit including a plurality of batteries electrically connected to the LED display layer and the photovoltaic cell layer. Electricity generated in the photovoltaic cell layer is stored in the battery unit, and the LED display layer is driven by the power stored in the battery unit.

[0006] According to the above LED display device, it is possible to provide an LED display device that can operate for a long period of time.

[0007] FIG. 1 is a schematic perspective view showing the structure of an LED display device according to a first embodiment. FIG. 2 is a schematic perspective view showing the LED display device in a deformed state. FIG. 3 is a schematic perspective view showing the LED display device in a deformed state. FIG. 4 is a schematic plan view showing the surface structure of an LED display layer. FIG. 5 is a schematic plan view showing the surface structure of a battery unit. FIG. 6 is a schematic cross-sectional view showing the structure of an LED display device according to the first embodiment. FIG. 7 is a schematic perspective view showing the appearance of a battery. FIG. 8 is a schematic cross-sectional view showing the structure of a battery. FIG. 9 is a schematic cross-sectional view showing the structure of a battery. FIG. 10 is a schematic perspective view showing the structure of an LED display device according to a second embodiment. FIG. 11 is a schematic cross-sectional view showing the structure of an LED display device according to the second embodiment. FIG. 12 is a schematic perspective view showing the structure of an LED display device according to a third embodiment. FIG. 13 is a schematic perspective view showing the LED display device in a deformed state. FIG. 14 is a schematic perspective view showing the LED display device in a deformed state. FIG. 15 is a schematic cross-sectional view showing the structure of an LED display device according to the third embodiment.

[0008] [Summary of the embodiment] First, embodiments of the present disclosure will be listed and described. The LED display device of the present disclosure includes an LED display layer having surfaces opposite to each other in a thickness direction and including a plurality of LED elements arranged along one of the surfaces, a photovoltaic cell layer arranged alongside one of the surfaces of the LED display layer, and a battery unit including a plurality of batteries electrically connected to the LED display layer and the photovoltaic cell layer. Electricity generated in the photovoltaic cell layer is stored in the battery unit, and the LED display layer is driven by the power stored in the battery unit.

[0009] In the LED display device of the present disclosure, power generated in the photovoltaic cell layer is stored in a battery unit, and the LED display layer is driven by the power stored in the battery unit. Power is generated when the photovoltaic cell layer is irradiated with light such as sunlight. Therefore, when the LED display device of the present disclosure is used in an environment where the photovoltaic cell layer is irradiated with light, such as outdoors, it can operate using not only the power originally stored in the battery unit but also the power generated in the photovoltaic cell layer. As a result, the LED display device of the present disclosure can operate for a long period of time. Note that the photovoltaic cell layer can generate power not only from sunlight but also from other light sources, including artificially generated light. The photovoltaic cell layer generates power when irradiated with at least one of visible light, infrared light, and ultraviolet light.

[0010] In the LED display device, at least one of the LED display layer, the photovoltaic cell layer and the battery unit may have elasticity, which increases the degree of freedom in installation of the LED display device.

[0011] In the LED display device, the LED display layer, the photovoltaic cell layer, and the battery unit may be elastic. This configuration improves the flexibility of installation of the LED display device and also makes the LED display device easier to transport.

[0012] In the LED display device, the LED elements may be arranged in a matrix, which makes it easy to display various images on the LED display layer.

[0013] In the LED display device, the battery may be a lithium-ion battery. Lithium-ion batteries are compact, have high output, and are less susceptible to deterioration due to repeated charging and discharging, making them suitable for use as batteries in the battery unit of the LED display device of the present disclosure.

[0014] In the LED display device, the batteries may be arranged in an array, which allows a large number of batteries to be arranged efficiently.

[0015] In the LED display device, the photovoltaic cell layer has surfaces located opposite to each other in the thickness direction, and one of the surfaces of the photovoltaic cell layer faces one of the surfaces of the LED display layer. By stacking the photovoltaic cell layer and the LED display layer in this manner, it is easy to make the LED display device compact.

[0016] In the LED display device, the LED display layer and the photovoltaic cell layer may be laminated, and each cell may have a plate-like shape with surfaces located on opposite sides in the thickness direction. The cells may be arranged side by side so as to face either the LED display layer or the photovoltaic cell layer. This configuration makes it easy to make the LED display device compact.

[0017] In the LED display device, the thickness of each battery may be 1.0 mm or less, which makes it easy to make the LED display device thinner.

[0018] In the above LED display device, the capacity of each battery in the thickness direction is 100 mm. ２ This configuration can further extend the operating time of the LED display device.

[0019] In the LED display device, each battery may include a separator, a positive electrode layer and a negative electrode layer sandwiching the separator, an electrolyte impregnated in the separator, the positive electrode layer, and the negative electrode layer, and an exterior material that houses the separator, the positive electrode layer, the negative electrode layer, and the electrolyte. A battery having such a structure is suitable as a battery that constitutes a battery unit of the LED display device of the present disclosure.

[0020] In the LED display device, the positive electrode layer may be made of a sintered body, which makes it easy to achieve low resistance and large capacity for the battery.

[0021] In the LED display layer of the LED display device, the distance between two adjacent LED elements may be 4 mm or less. This configuration makes it easy to display high-definition images on the LED display layer.

[0022] In the LED display layer of the LED display device, the gap may be 1.27 mm or less. This configuration makes it easier to display higher-definition images on the LED display layer.

[0023] In the LED display device, an LED display layer, a photovoltaic cell layer, and a battery unit may be stacked in this order. The LED display layer may be light-transmitting. The LED elements may be located on the surface of the LED display layer, opposite the side to which the photovoltaic cell layer is attached. With this configuration, images can be displayed by light emitted by the LED elements on the surface of the LED display layer, and light transmitted through the LED display layer can be supplied to the photovoltaic cell layer.

[0024] In the LED display device, the photovoltaic cell layer may generate power from light transmitted through the LED display layer, which makes it easy to extend the operating time of the LED display device by using the power generated in the photovoltaic cell layer.

[0025] In the LED display device, the battery unit may reflect light, and this configuration allows the light reflected by the battery unit to be supplied to the photovoltaic cell layer.

[0026] In the above LED display device, the photovoltaic cell layer may generate power by light that is transmitted through the LED display layer and the photovoltaic cell layer and reflected by the battery unit, which configuration makes it easy to further extend the operating time of the LED display device by the power generated in the photovoltaic cell layer.

[0027] In the LED display device, a photovoltaic cell layer, an LED display layer, and a battery unit may be stacked in this order. The LED element may be located on one of the surfaces of the LED display layer and attached near the photovoltaic cell layer. This configuration makes it easy to supply light to the photovoltaic cell layer for power generation.

[0028] In the LED display device, the photovoltaic cell layer may be transparent, and an image provided by the LED display layer may be visible through the photovoltaic cell layer. This configuration makes it possible to provide an LED display device in which an image can be viewed through the photovoltaic cell layer.

[0029] In the LED display device, the photovoltaic cell layer may have a plurality of through-holes penetrating the photovoltaic cell layer in a thickness direction. The through-holes may correspond to the LED elements. Images provided by the LED display layer may be visible through the through-holes. This configuration makes it easy to view images through the photovoltaic cell layer.

[0030] In the above LED display device, the LED display layer and the photovoltaic cell layer may be stacked. The battery unit may have a rod-like shape including a pair of end faces and an outer circumferential surface connecting the pair of end faces. The battery unit may be attached to the LED display layer or the photovoltaic cell layer at the outer circumferential surface. The LED display layer and the photovoltaic cell layer may be elastic. With this configuration, the LED display device can be deformed so that the stacked LED display layer and the photovoltaic cell layer are wrapped around the rod-shaped battery body. As a result, the LED display device can be easily transported and stored.

[0031] [Specific Example of Embodiment] Next, specific examples of the LED display device of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated.

[0032] (Embodiment 1) FIG. 1 is a schematic perspective view showing the structure of an LED display device according to Embodiment 1. FIGS. 2 and 3 are schematic perspective views showing the LED display device in a deformed state. Referring to FIG. 1, the LED display device 1 of this embodiment includes an LED display layer 10, a photovoltaic cell layer 20, and a battery unit 30. The LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 each have a sheet-like shape. The LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 are stacked in this order. While other layers and other members may be interposed between the LED display layer 10 and the photovoltaic cell layer 20, in this embodiment, they are in contact with each other. While other layers and other members may be interposed between the photovoltaic cell layer 20 and the battery unit 30, they are in contact with each other in this embodiment. The LED display layer 10 and the photovoltaic cell layer 20 are bonded together. The bonding method is not particularly limited, and methods such as adhesion with an adhesive and fusion bonding can be used. Instead of bonding, the relative positions may be fixed by, for example, a frame member (not shown) that fixes the outer periphery. The photovoltaic cell layer 20 and the battery unit 30 are bonded. The means of bonding is not particularly limited, and means such as adhesion with an adhesive or fusion bonding can be used. Instead of bonding, the relative positions may be fixed by, for example, a frame member (not shown) that fixes the outer periphery.

[0033] In this embodiment, at least one of the LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 has elasticity. The LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 have elasticity. The LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 have flexibility. The LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 can be deformed into a curved shape. Therefore, the LED display device 1 of this embodiment can be in a flat state as shown in FIG. 1 or a curved state as shown in FIG. 2. This allows the LED display device 1 of this embodiment to be installed not only on a flat wall surface but also on a curved wall surface (for example, the surface of a cylindrical pillar). Furthermore, the LED display device 1 of this embodiment can also be deformed into a spiral shape as shown in FIG. 3. This allows the LED display device 1 of this embodiment to be easily stored and transported. The LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 may have rigidity rather than elasticity or flexibility.

[0034] Fig. 4 is a schematic plan view showing the surface structure of the LED display layer. Fig. 4 is a view of the first main surface 10A of the LED display layer 10 viewed in a direction perpendicular to the first main surface 10A. Fig. 5 is a schematic plan view showing the surface structure of the battery unit. Fig. 5 is a view of the second main surface 30B of the battery unit 30 viewed in a direction perpendicular to the second main surface 30B. Fig. 6 is a schematic cross-sectional view showing the structure of the LED display device of embodiment 1.

[0035] 1, 4, and 6, the LED display layer 10 has a first main surface 10A and a second main surface 10B, which are surfaces located opposite each other in the thickness direction. The LED display layer 10 includes a plurality of LED elements 11 arranged along the first main surface 10A. The LED display layer 10 includes a base layer 12 having a sheet-like shape and a plurality of LED elements 11 arranged on the base layer 12. As shown in FIG. 4, the plurality of LED elements 11 are arranged in a matrix. As shown in FIG. 6, in the LED display layer 10, the interval g between two adjacent LED elements 11 is１ can be set appropriately depending on the application, size, etc. of the LED display device 1, and may be, for example, 4 mm or less, 1 mm or less, 0.8 mm or less, 0.7 mm or less, 0.6 mm or less, 0.5 mm or less, 0.4 mm or less, 0.3 mm, or even 1.27 mm or less. The plurality of LED elements 11 are arranged over the entire area of ​​the first main surface 10A except for the outer periphery. The base layer 12 is electrically connected to the LED elements 11 and includes a circuit board that drives the LED elements 11.

[0036] The LED display layer 10 is translucent. Specifically, for example, the LED display layer 10 may transmit 60% or more, preferably 80% or more, of visible light having a wavelength of 360 nm or more and 830 nm or less (visible light) that is incident perpendicularly to the first main surface 10A. The LED elements 11 are present on the first main surface 10A, which is opposite to the second main surface 10B, which is the surface on which the photovoltaic cell layer 20 is attached. The LED elements 11 are disposed on the first main surface 10A, which is the surface opposite in the thickness direction to the second main surface 10B, which is the surface facing the photovoltaic cell layer 20.

[0037] 1 and 6 , the photovoltaic cell layer 20 has a first main surface 20A and a second main surface 20B, which are surfaces located opposite each other in the thickness direction. The photovoltaic cell layer 20 is arranged alongside the second main surface 10B, which is one of the surfaces of the LED display layer 10. The first main surface 20A, which is one of the surfaces of the photovoltaic cell layer 20, faces the second main surface 10B of the LED display layer 10. The first main surface 20A of the photovoltaic cell layer 20 and the second main surface 10B of the LED display layer 10 are in contact with each other. The photovoltaic cell layer 20 includes a photovoltaic cell that generates electricity through the photoelectric effect when irradiated with light, such as sunlight, including visible light. As described above, the LED display layer 10 of this embodiment is translucent. Referring to FIG. 6 , when light, such as sunlight, is irradiated onto the first main surface 10A of the LED display layer 10, a portion of the light, light B, passes through the LED display layer 10 and reaches the photovoltaic cell layer 20. The photovoltaic cell layer 20 generates electricity using this light B. The photovoltaic cell layer 20 is not limited to generating electricity from sunlight, and can also generate electricity using other light sources, including artificially generated light. The photovoltaic cell layer 20 generates electricity when irradiated with at least one of visible light, infrared light, and ultraviolet light. The photovoltaic cell layer 20 may be configured by arranging a plurality of cells in a matrix and electrically connecting them to each other.

[0038] 1, 5, and 6, the battery unit 30 has a first main surface 30A and a second main surface 30B, which are surfaces located opposite each other in the thickness direction. The battery unit 30 includes a plurality of batteries 31 arranged along the second main surface 30B. The first main surface 30A of the battery unit 30 faces the second main surface 20B of the photovoltaic cell layer 20. The battery unit 30 includes a base layer 32 having a sheet-like shape and a plurality of batteries 31 arranged on the base layer 32. As shown in FIG. 5, the plurality of batteries 31 are arranged in an array. The plurality of batteries 31 may be arranged in a plurality of parallel rows with intervals 33 therebetween, as shown in FIG. 6. Referring to FIG. 6, the thickness t of each battery 31 is 1 / 2 mm. ３can be appropriately set in consideration of the required capacity depending on the application of the LED display device 1, and may be, for example, 1.0 mm or less, 0.5 mm or less, or even 0.4 mm or less. The battery 31 is a secondary battery that can be charged and discharged. In this embodiment, the battery 31 is a lithium ion battery (lithium ion secondary battery).

[0039] Each battery 31 has a plate-like shape including a first main surface 31A and a second main surface 31B, which are surfaces located opposite each other in the thickness direction. The batteries 31 are arranged side by side with the photovoltaic cell layer 20 interposed therebetween, with the first main surface 31A facing the second main surface 10B of the LED display layer 10. More specifically, a base layer 32 is arranged so as to contact the second main surface 20B of the photovoltaic cell layer 20. The battery 31 is arranged on the base layer 32 so as to contact the base layer 32 at the first main surface 31A. Note that the base layer 32 is not essential and may be omitted. In other words, the battery 31 may be arranged directly on the photovoltaic cell layer 20 so as to contact the second main surface 20B of the photovoltaic cell layer 20 at the first main surface 31A.

[0040] When viewed in the thickness direction of the battery 31 (as viewed from the viewpoint of FIG. 5), the capacity of each battery 31 is, for example, 100 mm ２Preferably, the photovoltaic cell layer 20 has a power dissipation of 70 mWh or more, 85 mWh or more, and even 100 mWh or more per unit area. In this embodiment, the photovoltaic cell layer 20 may be translucent. Specifically, for example, the photovoltaic cell layer 20 may transmit 60% or more, preferably 80% or more, of visible light having a wavelength of 360 nm or more and 830 nm or less (visible light) that is incident perpendicularly to the first main surface 20A. The battery unit 30 may also reflect light. In this case, referring to FIG. 6 , when light such as sunlight is irradiated onto the first main surface 10A of the LED display layer 10, a portion of the light, light C, passes through the LED display layer 10 and the photovoltaic cell layer 20 and reaches the battery unit 30. The base layer 32 of the battery unit 30 has a power dissipation property similar to the photovoltaic cell layer 20. On the other hand, the first main surface 31A of the battery 31 has, for example, a metallic luster. As a result, light C is reflected by the first main surface 31A of the battery 31 and reaches the photovoltaic cell layer 20. The photovoltaic cell layer 20 generates electricity from this light C.

[0041] Next, the internal structure of the battery 31 will be described. Fig. 7 is a schematic perspective view showing the appearance of the battery (lithium ion secondary battery). Fig. 8 is a schematic cross-sectional view showing a cross section along line VIII-VIII in Fig. 7. Fig. 9 is a schematic cross-sectional view showing a cross section along line IX-IX in Fig. 7.

[0042] 7 to 9 , a lithium-ion secondary battery 31 includes a pair of exterior films 310, a battery main body 320, a positive electrode tab terminal 331, and a negative electrode tab terminal 332. Each exterior film 310 has the same rectangular shape when viewed in the thickness direction. The surface of each exterior film 310 has a metallic luster. In the pair of exterior films 310, first outer edges 311 corresponding to the first short sides of the rectangle, second outer edges 312 corresponding to the first long sides, third outer edges 313 corresponding to the second short sides, and fourth outer edges 314 corresponding to the second long sides are joined to each other.

[0043] More specifically, the first outer edges 311 are bonded to each other over their entire area except for the portions facing each other across the positive electrode tab terminal 331 and the negative electrode tab terminal 332 (see FIG. 9 ). The second outer edges 312, the third outer edges 313, and the fourth outer edges 314 are bonded to each other over their entire circumferential area. In this embodiment, the outer edges 311 to 314 are bonded by fusion. The bonding can be achieved by heat fusion. That is, in the pair of exterior films 310, the outer edges 311 to 314 are bonded (fused) to each other in a stacked state. Referring to FIG. 8 , the pair of exterior films 310 each include an inner surface 310A that faces each other and an outer surface 310B that is the main surface opposite the inner surface 310A. An internal space 310C is formed between the opposing inner surfaces 310A of the pair of exterior films 310.

[0044] 8 , the internal space 310C accommodates a battery body 320. The battery body 320 includes a separator film 321, a positive electrode layer 322, a negative electrode layer 323, a positive electrode current collector foil 324, a negative electrode current collector foil 325, and an electrolyte 326.

[0045] The separator film 321 is a film made of resin. Examples of resins that can be used to form the separator film 321 include polyolefin, polyimide, polyester (e.g., polyethylene terephthalate (PET)), and cellulose.

[0046] The positive electrode layer 322 is laminated on a first main surface 321A, which is one of the main surfaces of the separator film 321. The positive electrode layer 322 of this embodiment is made of a plate-shaped sintered body of lithium composite oxide. The positive electrode layer 322 does not contain a binder. The lithium composite oxide is a material containing Li ｘ MO ２ (0.05<x<1.10, M is at least one transition metal, and M typically includes one or more of Co (cobalt), Ni (nickel), and Mn (manganese)).

[0047] The negative electrode layer 323 is laminated on a second main surface 321B located on the opposite side in the thickness direction to the first main surface 321A of the separator film 321. The negative electrode layer 323 contains carbon such as graphite as a negative electrode active material, and a binder such as styrene butadiene rubber (SBR) or polyvinylidene fluoride (PVDF).

[0048] The positive electrode current collector foil 324 is laminated on the side of the positive electrode layer 322 opposite the separator film 321. The positive electrode current collector foil 324 is a foil made of a metal that is an electrical conductor. For example, Al (aluminum) can be used as the metal constituting the positive electrode current collector foil 324. The positive electrode current collector foil 324 is disposed between the positive electrode layer 322 and the inner surface 310A of the exterior film 310. The positive electrode current collector foil 324 is disposed along the inner surface 310A of the exterior film 310.

[0049] The negative electrode current collector foil 325 is laminated on the negative electrode layer 323 on the side opposite to the separator film 321. The negative electrode current collector foil 325 is a foil made of a metal that is an electrical conductor. Examples of metals that can be used to form the negative electrode current collector foil 325 include Cu (copper) and Al. The negative electrode current collector foil 325 is disposed between the negative electrode layer 323 and the inner surface 310A of the exterior film 310. The negative electrode current collector foil 325 is disposed along the inner surface 310A of the exterior film 310.

[0050] The electrolyte 326 is impregnated into the separator film 321, the positive electrode layer 322, and the negative electrode layer 323. The electrolyte 326 is a solution of a lithium salt (e.g., LiPF ) in an organic solvent (e.g., a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (MEC), a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC), or a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC)). ６ ) A solution in which a salt is dissolved can be used.

[0051] The positive electrode tab terminal 331 is connected to the battery main body 320 between the pair of exterior films 310 and extends to the outside. The negative electrode tab terminal 332 is connected to the battery main body 320 between the pair of exterior films 310 and extends to the outside. The positive electrode tab terminal 331 is connected to the positive electrode current collector foil 324. The negative electrode tab terminal 332 is connected to the negative electrode current collector foil 325. The positive electrode tab terminal 331 and the negative electrode tab terminal 332 have a strip-like shape. Referring to FIG. 9 , the positive electrode tab terminal 331 includes a conductive main body 331A and a resin protective layer 331B arranged to cover the surface of the main body 331A. The negative electrode tab terminal 332 includes a conductive main body 332A and a resin protective layer 332B arranged to cover the surface of the main body 332A. The conductors constituting the main bodies 331A and 332A may be metals such as aluminum (Al) and nickel (Ni).

[0052] Referring to FIG. 6 , the battery unit 30 is electrically connected to the LED display layer 10 via wiring 91. The battery unit 30 is electrically connected to the photovoltaic cell layer 20 via wiring 92. Note that the wiring 91 and wiring 92 are exemplary, and the electrical connection may be achieved by wiring exposed to the outside as shown in FIG. 6 , or by joining conductive pads formed on the surfaces of the LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 together using solder or the like. Furthermore, the LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 may each be electrically connected to a control board separate from these components. The battery unit 30 may be indirectly connected to at least one of the LED display layer 10 and the photovoltaic cell layer 20 via the control board. In this case, the control board may be responsible for voltage conversion of power, as described below. Furthermore, the control board may not be a separate component, but may be incorporated into the LED display layer 10, the photovoltaic cell layer 20, or the battery unit 30 as part of the LED display layer 10, the photovoltaic cell layer 20, or the battery unit 30.

[0053] Referring to FIG. 6 , in the LED display device 1 of this embodiment, power generated in the photovoltaic cell layer 20 is stored in the battery unit 30. The LED display layer 10 is driven by the power stored in the battery unit 30. More specifically, the LED elements 11 included in the LED display layer 10 emit light along the arrow A. As a result, a desired image is formed on the first main surface 10A of the LED display layer 10. Therefore, when the LED display device 1 is used in an environment exposed to light, such as outdoors, it can operate using not only the power originally stored in the battery unit 30 but also the power generated in the photovoltaic cell layer 20. In particular, the photovoltaic cell layer 20 can generate power not only from light B that passes through the LED display layer 10 and reaches the photovoltaic cell layer 20 but also from light C that passes through the LED display layer 10 and the photovoltaic cell layer 20, reflects off the battery unit 30 (the first main surface 30A of the battery 31), and reaches the photovoltaic cell layer 20. As a result, the LED display device 1 of this embodiment is an LED display device that can operate for a long period of time. It should be noted that a portion of the power generated in the photovoltaic cell layer 20 may be used directly to drive the LED display layer 10 without being stored in the battery unit 30 .

[0054] Second Embodiment Next, a second embodiment of the present disclosure will be described. FIG. 10 is a schematic perspective view showing the structure of an LED display device according to the second embodiment. FIG. 11 is a schematic cross-sectional view showing the structure of an LED display device according to the second embodiment. FIGS. 10 and 11 correspond to FIGS. 1 and 6 in the first embodiment. Referring to FIGS. 10 and 11 and 1 and 6, the LED display device 1 according to the second embodiment basically has the same configuration and produces the same effects as the LED display device 1 according to the first embodiment. However, the LED display device 1 according to the second embodiment differs from the first embodiment in the stacking order of the LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30. The following mainly describes the differences from the first embodiment.

[0055] 10 and 11 , in the LED display device 1 of the second embodiment, the photovoltaic cell layer 20, the LED display layer 10, and the battery unit 30 are stacked in this order. The first main surface 10A of the LED display layer 10 faces the second main surface 20B of the photovoltaic cell layer 20. As a result, the LED elements 11 arranged on the first main surface 10A are attached in the vicinity of the photovoltaic cell layer 20. The first main surface 30A of the battery unit 30 faces the second main surface 10B of the LED display layer 10. The batteries 31 are arranged side by side facing the LED display layer 10 with the base layer 32 sandwiched therebetween.

[0056] 11 , in the LED display device 1 of this embodiment, when light such as sunlight is irradiated onto the first main surface 20A of the photovoltaic cell layer 20, electricity is generated by a portion of the light, light D. Furthermore, the LED display layer 10 and the photovoltaic cell layer 20 of this embodiment are translucent. Therefore, when light such as sunlight is irradiated onto the first main surface 20A of the photovoltaic cell layer 20, a portion of the light, light E, passes through the photovoltaic cell layer 20 and the LED display layer 10, is reflected by the battery unit 30 (first main surface 31A of battery 31), and then passes through the LED display layer 10 to reach the photovoltaic cell layer 20. Electricity is also generated by this light E.

[0057] Referring to FIG. 11 , the battery unit 30 is electrically connected to the LED display layer 10 via wiring 93. The battery unit 30 is electrically connected to the photovoltaic cell layer 20 via wiring 94. Note that the wiring 93 and wiring 94 are merely examples, and the electrical connection may be achieved by wiring exposed to the outside as shown in FIG. 11 , or by joining conductive pads formed on the surfaces of the LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 together using solder or the like. Furthermore, the LED display layer 10, the photovoltaic cell layer 20, and the battery unit 30 may each be electrically connected to a control board separate from these components. The battery unit 30 may be indirectly connected to at least one of the LED display layer 10 and the photovoltaic cell layer 20 via the control board. In this case, the control board may be responsible for voltage conversion of the power, as described below. Furthermore, the control board may not be a separate component, but may be incorporated into the LED display layer 10, the photovoltaic cell layer 20, or the battery unit 30 as part of the LED display layer 10, the photovoltaic cell layer 20, or the battery unit 30.

[0058] Referring to FIG. 11 , in the LED display device 1 of this embodiment, too, the power generated in the photovoltaic cell layer 20 is stored in the battery unit 30. The LED display layer 10 is driven by the power stored in the battery unit 30. More specifically, the LED elements 11 included in the LED display layer 10 emit light along the arrow A. The photovoltaic cell layer 20 of this embodiment has a plurality of through holes 29 penetrating the photovoltaic cell layer 20 in the thickness direction. The through holes 29 are arranged corresponding to the LED elements 11. Therefore, the light emitted along the arrow A passes through the through holes 29 and reaches the outside of the LED display device 1. As a result, an image provided by the LED display layer 10 is visible through the photovoltaic cell layer 20. More specifically, the image provided by the LED display layer 10 is visible through the through holes 29.

[0059] In this way, when the LED display device 1 of this embodiment is used in an environment where light is irradiated, such as outdoors, it can operate using the power generated in the photovoltaic cell layer 20 in addition to the power that has been stored in the battery unit 30 from the beginning. As a result, the LED display device 1 of this embodiment is an LED display device that can operate for a long period of time.

[0060] Third Embodiment Next, a third embodiment of the present disclosure will be described. FIG. 12 is a schematic perspective view showing the structure of an LED display device according to the third embodiment. FIGS. 13 and 14 are schematic perspective views showing a deformed state of the LED display device. FIG. 15 is a schematic cross-sectional view showing the structure of an LED display device according to the third embodiment. FIGS. 12, 13, 14, and 15 correspond to FIGS. 1, 2, 3, and 6 in the first embodiment, respectively. Referring to FIGS. 12 to 15 and FIGS. 1 to 3 and 6, the LED display device 1 according to the third embodiment basically has the same configuration and produces the same effects as the LED display device 1 according to the first embodiment. However, the LED display device 1 according to the third embodiment differs from the first embodiment in the structure and arrangement of the battery unit. The following mainly describes the differences from the first embodiment.

[0061] Referring to FIG. 12 , the battery unit 34 of this embodiment has a rod-like shape including a pair of end surfaces 35A and an outer circumferential surface 35B connecting the pair of end surfaces 35A. The battery unit 34 may have a structure in which a plurality of cylindrical batteries 35 are connected in an axial direction, as shown in FIG. 12 . The battery unit 34, which is composed of a plurality of batteries 35, is attached to the LED display layer 10 at the outer circumferential surface 35B. The controller 36 is attached to the LED display layer 10. The battery unit 34 (a plurality of batteries 35) and the controller 36 may be attached to the photovoltaic cell layer 20 instead of the LED display layer 10. The battery unit 34 and the LED display layer 10 are electrically connected by wiring 95. The battery unit 34 and the photovoltaic cell layer 20 are electrically connected by wiring 96.

[0062] In this embodiment, the LED display layer 10 and the photovoltaic cell layer 20 are elastic. The LED display layer 10 and the photovoltaic cell layer 20 are flexible. The LED display layer 10 and the photovoltaic cell layer 20 can be deformed into a curved shape. Therefore, the LED display device 1 of this embodiment can be in a flat state as shown in FIG. 12 or a curved state as shown in FIG. 13 . This allows the LED display device 1 of this embodiment to be installed not only on a flat wall surface but also on a curved wall surface (for example, the surface of a cylindrical pillar). The LED display device 1 of this embodiment can also be deformed into a spiral shape as shown in FIG. 14 . More specifically, it can be deformed into a spiral shape around the outer circumferential surface 35B of the battery unit 34 (plurality of batteries 35) so as to surround the outer circumferential surface 35B. This allows the LED display device 1 of this embodiment to be easily stored and transported.

[0063] 15 , in the LED display device 1 of this embodiment, the power generated in the photovoltaic cell layer 20 is stored in the battery unit 34. The LED display layer 10 is driven by the power stored in the battery unit 34. Therefore, when the LED display device 1 is used in an environment where light is irradiated, such as outdoors, it can operate using the power generated in the photovoltaic cell layer 20 in addition to the power originally stored in the battery unit 34. As a result, the LED display device 1 of this embodiment, like the first embodiment, is an LED display device that can operate for a long period of time.

[0064] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not limiting in any respect. The scope of the present disclosure is defined not by the above description but by the scope of the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0065] 1 LED display device, 10 LED display layer, 10A first main surface, 10B second main surface, 11 LED element, 12 base layer, 20 photovoltaic cell layer, 20A first main surface, 20B second main surface, 29 through hole, 30 battery unit, 30A first main surface, 30B second main surface, 31 battery, 31A first main surface, 31B second main surface, 32 base layer, 34 battery unit, 35 battery, 35A end surface, 35B outer peripheral surface, 36 controller, 91 wiring, 92 wiring, 95 wiring, 96 wiring, 310 exterior film, 310A inner surface, 310B outer surface, 310C internal space, 311 first outer edge, 312 second outer edge, 313 third outer edge, 314 fourth outer edge, 320 battery body, 321 Separator film, 321A first main surface, 321B second main surface, 322 positive electrode layer, 323 negative electrode layer, 324 positive electrode current collector foil, 325 negative electrode current collector foil, 326 electrolyte, 331 positive electrode tab terminal, 331A main body, 331B protective layer, 332 negative electrode tab terminal, 332A main body, 332B protective layer.

Claims

1. An LED display device comprising: an LED display layer having surfaces located on opposite sides in the thickness direction and including a plurality of LED elements arranged along one of the surfaces; a photovoltaic cell layer arranged side by side with one of the surfaces of the LED display layer; and a battery unit including a plurality of batteries electrically connected to the LED display layer and the photovoltaic cell layer, wherein the electric power generated in the photovoltaic cell layer is stored in the battery unit, and the LED display layer is driven by the electric power stored in the battery unit.

2. The LED display device according to claim 1, wherein at least one of the LED display layer, the photovoltaic cell layer, and the battery unit has elasticity.

3. The LED display device according to claim 1, wherein the LED elements are arranged in a matrix.

4. The LED display device according to claim 1, wherein the battery is a lithium ion battery.

5. The LED display device according to claim 1, wherein the batteries are arranged in an array.

6. The LED display device according to claim 1, wherein the photovoltaic cell layer has surfaces located on opposite sides in the thickness direction, and one of the surfaces of the photovoltaic cell layer faces one of the surfaces of the LED display layer.

7. The LED display device according to claim 1, wherein the LED display layer and the photovoltaic cell layer are laminated, each battery has a plate-like shape having surfaces located on opposite sides in the thickness direction, and the batteries are arranged side by side so as to face either the LED display layer or the photovoltaic cell layer.

8. The LED display device according to claim 1, wherein the LED display layer and the photovoltaic cell layer are laminated, the battery unit has a rod-like shape including a pair of end faces and an outer peripheral surface connecting the pair of end faces, and the battery unit is attached to the LED display layer or the photovoltaic cell layer on the outer peripheral surface.

9. The LED display device according to claim 1, wherein the thickness of each battery is 1.0 mm or less.

10. The capacity of each of the batteries as viewed in the thickness direction is 70 mWh or more per 100 mm ２ The LED display device according to claim 1, wherein the capacity is 70 mWh or more per 100 mm 11. Each of the batteries includes a separator, a positive electrode layer and a negative electrode layer disposed with the separator therebetween, an electrolytic solution impregnated in the separator, the positive electrode layer and the negative electrode layer, and an exterior member that houses the separator, the positive electrode layer, the negative electrode layer and the electrolytic solution, and is the LED display device according to claim 1.

12. The positive electrode layer is composed of a sintered body, and is the LED display device according to claim 11.

13. In the LED display layer, the distance between two adjacent LED elements is 4 mm or less, and is the LED display device according to claim 1.

14. The distance is 1.27 mm or less, and is the LED display device according to claim 13.

15. The LED display layer, the photovoltaic cell layer and the battery unit are laminated in this order, the LED display layer is translucent, and the LED element is on the surface of the LED display layer and on the opposite side where the photovoltaic cell layer is attached, and is the LED display device according to claim 1.

16. The photovoltaic cell layer generates electric power by the light transmitted through the LED display layer, and is the LED display device according to claim 15.

17. The battery unit reflects light, and is the LED display device according to claim 15.

18. The photovoltaic cell layer also generates electric power by the light transmitted through the LED display layer and the photovoltaic cell layer and reflected by the battery unit, and is the LED display device according to claim 17.

19. The photovoltaic cell layer, the LED display layer and the battery unit are laminated in this order, the LED element is on one of the surfaces of the LED display layer and is attached in the vicinity of the photovoltaic cell layer, and is the LED display device according to claim 1.

20. The photovoltaic cell layer is translucent, and the image provided by the LED display layer is visible through the photovoltaic cell layer, and is the LED display device according to claim 19.

21. The photovoltaic cell layer has a plurality of through holes penetrating in the thickness direction, the through holes correspond to the LED elements, and the image provided by the LED display layer is visible through the through holes, and is the LED display device according to claim 19.

Images