JP7513992B2 - Thin non-powered display device - Google Patents

Description

The present invention relates to a display device that is thin, does not require an external power supply, and is capable of changing and maintaining the display content as an independent device.

Currently, there is a demand for display devices that are excellent in appearance and functionality and that can be easily installed.

By using a display device such as a general liquid crystal display or organic electroluminescence (EL), it is possible to change and maintain the displayed content. However, a power source is required, and there is a problem that the power cord detracts from the appearance and functionality of the display device.

In addition, while a power source can be secured by using solar panels as the power source, a considerably large panel is required to provide sufficient power to operate a typical liquid crystal display, etc., and the problem of impairing the appearance and functionality of the display device cannot be solved.

2. Description of the Related Art Conventionally, an advertising device that combines a solar system function and an advertising function has been known (Patent Document 1).

However, this technology did not link the solar system function with the advertising function. In other words, the advertising envisioned was not something that consumed electricity, but rather it displayed fixed advertising content with graphic designs printed on the surface of a film such as polyvinyl chloride, and the generated electricity was not used to change or maintain the advertising content.

Furthermore, a traffic sign equipped with a solar cell panel is known as a solar cell composite display (Patent Document 2).

However, this technology works by storing electricity generated by solar panels during the day and using this stored electricity as a power source for lighting, improving visibility at night and attracting attention during the day; the generated electricity is not used to change or maintain the content of the advertisements.

Also, a bulletin board is known in which an electronic display device and a solar cell are attached in opposite directions around a support member, and the solar cell generates electricity to be supplied to the electronic display device (Patent Document 2).
However, this technology is an invention for a bulletin board, and is not a thin device. Rather, it requires a certain thickness to maintain a self-supporting structure as a bulletin board. In addition, there is no description of a configuration for achieving power saving.

Patent Publication 2011-70065 Patent Publication No. 2017-46496 Patent Publication No. 2020-52077

The present invention has been made in consideration of the above points, and aims to provide a display device that is thin, does not require an external power supply, and can change and maintain the display content while saving power as an independent device.

The thin, unpowered display device of the present invention is a thin, unpowered display device having an overall thickness of 7 mm or less, comprising a memory-type reflective display unit, a thin solar cell module, a fixing unit, and a control unit, in which the memory-type reflective display unit and the thin solar cell module are respectively arranged on both outer flat surfaces of the thin, unpowered display device, the thin, unpowered display device operates using only the thin solar cell module as a power source, and the fixing unit is arranged on either surface of the memory-type reflective display unit or the thin solar cell module, making it possible to fix the thin, unpowered display device to a transparent structure without impairing the functions of either of them.

The thin, non-powered display device of the present invention further comprises a storage section, a communication section, and a film-type secondary battery, and is characterized in that it can store electricity in the film-type secondary battery.

According to the present invention, it is possible to provide a display device that is thin, does not require an external power supply, and is capable of changing and maintaining the display content while saving power as an independent device.

1 is a diagram illustrating an outline of a main body of a thin, non-powered display device 100 according to an embodiment of the present invention. FIG. 1 is a diagram (1) for explaining a state in which the thin, non-powered display device 100 according to the present embodiment is attached to a transparent structure. FIG. 4 is a diagram (2) for explaining a state in which the thin, non-powered display device 100 according to the present embodiment is attached to a transparent structure. FIG. 3 is a diagram for explaining a state in which the thin, non-powered display device 100 according to the present embodiment is attached to a transparent structure. FIG. 4 is a diagram for explaining a state in which the thin, non-powered display device 100 according to the present embodiment is attached to a transparent structure. FIG. 1 is a diagram (1) for explaining the function of the main body of the thin, non-powered display device 100 according to the present embodiment. FIG. 5 is a diagram (5) for explaining a state in which the thin, non-powered display device 100 according to the present embodiment is attached to a transparent structure. FIG. 4 is a diagram (2) for explaining the function of the main body of the thin, non-powered display device 100 according to the present embodiment.

Hereinafter, an embodiment for carrying out the thin non-powered display device of the present invention will be described in detail, however, the present invention is not limited to the following embodiment.

(Thin, non-powered display device)
Fig. 1(a) is an overall perspective view of a main body of a thin, non-powered display device 100 according to this embodiment. The main body refers to a configuration of the thin, non-powered display device 100 of the present invention that does not include a fixing part. The thin, non-powered display device 100 of the present invention is configured by arranging a fixing part on either one of the two outer surfaces of the main body in Fig. 1, and is fixed to a transparent structure via this fixing part.

A reflective display unit with a memory effect 1 is disposed on one outer flat surface of the main body (FIG. 1(b)), and a thin solar cell module 2 is disposed on the opposite outer flat surface (FIG. 1(c)).

There is no particular limit to the size of the thin, non-powered display device 100. The entire thin, non-powered display device 100 is a thin, flat-plate device having a thickness of 7 mm or less, preferably 3 mm or less. This thinness is achieved by making each of the members, such as the memory-type reflective display unit 1, the thin solar cell module 2, the fixing unit, and the control board, thin.

The power source of the thin, non-powered display device 100 is basically only the thin solar cell module 2. The thin, non-powered display device 100 may also be equipped with a film-type secondary battery, in which case the thin solar cell module 2 and the film-type secondary battery can serve as the power source. In some cases, the thin, non-powered display device 100 may have a connection terminal for receiving a supply of an external power source.

It is desirable that the memory-type reflective display unit and the thin solar cell module each occupy 90% or more of the outer flat surface of the thin non-powered display device 100. This is to increase the area of the functional parts and increase the efficiency and functional density of the device.

(Reflective display with memory function)
The display unit of the present invention is a reflective display unit with a memory function. The memory function refers to a characteristic that even if the power is turned off or only a weak current is applied, the immediately preceding image or image data remains without outputting image data from an external control, and does not require a large current except when the display is changed. This characteristic makes it possible to retain the display contents even without power or with only a weak current. In addition, the reflective type refers to a configuration that uses external light such as ambient lighting as a light source by having a reflective structure, and does not require a backlight system like a normal liquid crystal. The memory function and reflective type make it possible to reduce power consumption.

A specific example of a memory-type reflective display unit is a memory-in-pixel reflective liquid crystal display. In a memory-in-pixel liquid crystal display, each pixel has a memory, and when displaying a still image, the image can be displayed using a video signal stored in the memory. Once an image is created on the display, the image can be maintained in the displayed state by simply passing a weak current thereafter. A memory-in-pixel reflective liquid crystal display that employs a reflective structure is a memory-in-pixel reflective liquid crystal display. For example, a color reflective liquid crystal with a memory-in-pixel function manufactured by Japan Display Inc. can be used as such a memory-in-pixel reflective liquid crystal display (https://www.j-display.com/product/reflective.html).

Another specific example of the memory-type reflective display unit is memory-type reflective electronic paper. There are various types and methods of electronic paper, one of which has a structure in which electronic ink such as a particle rotation type or electrophoretic type is arranged between an upper electrode and a lower electrode, and consumes power when switching the display content, but is known to be a type that can maintain the display state even when there is no power supply. This type of electronic paper usually adopts a reflective structure. Such electronic paper can be called memory-type reflective electronic paper. For such memory-type reflective electronic paper, it is possible to use, for example, electronic paper manufactured by Toppan Printing Co., Ltd. (https://www.toppan.co.jp/denshipaper/search/product/dotmatrix.html).

Since the total thickness of the thin, non-powered display device 100 is 7 mm or less, preferably 3 mm or less, the thickness of the memory-type reflective display section is 5 mm or less, preferably 2 mm or less. Japan Display Inc. manufactures a color reflective liquid crystal display with a memory-in-pixel function with a model number having a module thickness of 1.39 mm (LPM027M128B). Toppan Printing Co., Ltd. manufactures a memory-type reflective electronic paper with a module thickness of 1.2 mm (Aurora Mb (V231)). By employing these commercially available memory-type reflective display sections, it is possible to realize the thin, non-powered display device of the present invention.

The reflective display with memory has a display memory for storing images in the display itself, and the display memory can store multiple images.

(Thin solar cell module)
In recent years, it has become possible to manufacture thin and lightweight solar cell modules by preparing solar cells on polymer film substrates using a coating process. The use of a film substrate enables roll-to-roll manufacturing, which is expected to reduce manufacturing costs. As such coating-type solar cells, organic thin-film solar cells, dye-sensitized solar cells, perovskite solar cells (JP Patent Publication 2021-132233), etc. are known.

As the thin solar cell module of the present invention, for example, a film solar cell (BCS series) from TDK Corporation can be used. This film solar cell is thin with a thickness of 0.2 mm or less, lightweight, has high power generation efficiency under fluorescent lamps or LED light sources, and can be used indoors.

The thin solar cell module of the present invention is electrically connected to the reflective display unit with memory and receives external light to generate electricity and supply power to the reflective display unit with memory. Therefore, the thin non-powered display device can be operated as long as there is sufficient external light.

A color solar cell or a see-through type solar cell can be used as the thin solar cell module of the present invention. An example of a color solar cell is a dye-sensitized solar cell (DSSC) RICOH EH DSSC5284a manufactured by Ricoh Japan Co., Ltd. An example of a see-through type solar cell is an organic thin-film solar cell (OPV) manufactured by the same company.

A typical solar cell is close to black in color, and when used in the thin, non-powered display device of the present invention, there is no problem in terms of the power supply function, but to the observer, it appears boring and inorganic. If a thin solar cell module can display characters or designs without impairing the power supply function, further information and designs can be added to the thin, non-powered display device of the present invention, making it possible to provide information and entertainment to the observer.

Here, in the thin solar cell module of the present invention, color solar cells are used as some of the solar cells, and by arranging the color solar cells, letters or designs can be added to the outer surface of the thin solar cell module, making it possible to display a fixed message or a fixed design on the thin solar cell module. By arranging color solar cell units in the form of letters within a gray or black solar cell module, it becomes possible to add letters or designs. As a result, even if the thin, non-powered display device of the present invention is fixed to a transparent structure, an observer can see the thin solar cell module and understand the fixed message or design. Such fixed messages and fixed designs can also be added by printing.

The same thing can be achieved by adopting a see-through solar cell in the thin solar cell module of the present invention, and by providing text or a design on the back of the see-through solar cell so that the text or design can be observed through the see-through solar cell. Since the back of a see-through solar cell is visible, if text or a design is provided on the surface of the control board, for example, on the side of the thin solar cell module, which is located at the back, the text or design can be observed through the see-through solar cell.

(Fixed part)
The fixing part fixes the main body of the thin non-powered display device 100 to a transparent structure, and is disposed on either the surface of the memory-type reflective display part of the main body or the thin solar cell module. The fixing part is not particularly limited as long as it does not impair the function of the memory-type reflective display part or the thin solar cell module and can stably fix the main body to the transparent structure.

The fixed portion that does not impair the function of the reflective display portion with memory means that it does not obstruct the display of the reflective display portion with memory, which displays information, advertisements, etc., when viewed from the outside.

A fixing portion that does not impair the function of the thin solar cell module means a fixing portion that does not significantly impair the power generation function of the thin solar cell module that receives external light and generates power.

An example of the fixing part is a colorless and transparent adhesive sheet that covers the entire surface of one of the surfaces of the main body of the thin non-powered display device 100. A colorless and transparent adhesive sheet can be suitably used because it hardly absorbs light in the wavelength range required for power generation of the thin solar cell module even if it is placed on the thin solar cell module side. Examples of colorless and transparent adhesive sheets include optical transparent adhesive sheets (LUCIACS (registered trademark) CS986 series) manufactured by Nitto Denko Corporation and double-sided adhesive sheets (MHM-FWD series) manufactured by Nihon Ei Shinka Co., Ltd. Either of them can be used with a thickness of less than 0.1 mm.

The fixing part preferably blocks 99% or more of near-ultraviolet rays with wavelengths of 380 to 200 nm. This is because, when the thin, non-powered display device of the present invention is installed in a position where it receives sunlight, the near-ultraviolet rays contained in the sunlight may deteriorate the display function of the memory-type reflective display part and the power generation function of the thin solar cell module. The fixing part itself may contain a near-ultraviolet absorbing agent, or a near-ultraviolet absorbing film sandwiched between two colorless, transparent adhesive sheets may be used as the fixing part.

Fig. 2(a) is a diagram showing a state in which the thin, non-powered display device 100 of the present invention is fixed to glass (transparent structure 10). Fig. 2(b) is an enlarged cross-sectional view thereof. The thin, non-powered display device 100 is fixed to the indoor side of the glass, and is arranged so that the thin solar cell module 2 faces the outdoor side. The thin solar cell module 2 receives external light 20 through the glass and the fixing part 3 to generate electricity. The memory-type reflective display unit 1 then displays display content to people inside the room.

Furthermore, a colorless and transparent adhesive sheet can be suitably used because even if it is disposed on the side of the memory type reflective display unit, it does not interfere with the display of the memory type reflective display unit when viewed from the outside.

Fig. 3(a) is a diagram showing a state in which the thin, non-powered display device 100 of the present invention is fixed to glass (transparent structure 10). Fig. 3(b) is an enlarged cross-sectional view thereof. The thin, non-powered display device 100 is fixed to the outdoor side of the glass, and is arranged so that the memory-type reflective display unit 1 faces the indoor side. Since the thin solar cell module 2 is arranged outdoors, it directly receives external light 20 and generates power. Then, the memory-type reflective display unit 1 displays display content to people indoors through the glass and the fixing unit 3.

Another example of the fixing portion is an opaque double-sided tape. The opaque double-sided tape is arranged to avoid the display portion of the memory-type reflective display portion or the power generation portion of the thin solar cell module. This allows the main body portion of the thin, unpowered display device 100 to be fixed to the transparent structure without impeding the display function of the memory-type reflective display portion or the power generation function of the thin solar cell module.

2 and 3, the thin, non-powered display device 100 is arranged so that people indoors can see it and generates power using outdoor light. Conversely, a thin, non-powered display device 100 is also conceivable, arranged so that people outdoors can see it and generates power using indoor light. In this case, the memory-type reflective display unit is fixed facing outdoors and the thin solar cell module is fixed facing indoors. Figures 4 and 5 are diagrams showing the state in which the thin, non-powered display device 100 of the present invention is fixed to glass (transparent structure 10) in such a manner. The orientation of the main body of the thin, non-powered display device 100 is reversed, but the fixing using a fixing unit is the same.

(Display Content)
The display contents displayed by the thin non-powered display device of the present invention include advertisements, various guides, illustrations, images, etc., and the contents are not particularly limited. The various guides include emergency information to be transmitted in the event of a power outage during a disaster or the like.

(Control Unit)
The control unit includes an integrated circuit and controls the operation of the thin, non-powered display device of the present invention.

(Power supply circuit)
The power supply circuit plays a role in transmitting the current generated in the thin solar cell module to the memory type reflective display unit.

(Memory unit)
The storage unit stores the display content. The display content may be stored in the initial state, or new display content may be acquired and stored through communication. The display content is also stored in the display memory within the reflective display unit with memory, but the storage unit can store display content of a volume that cannot be stored in the display memory. The control unit can transfer the display content stored in the storage unit to the display memory and replace it. This makes it possible to display more content on the display section within the reflective display unit with memory.

(Communications Department)
The communication unit is not particularly limited as long as it can communicate with the outside wirelessly, but is preferably Bluetooth (registered trademark), Wi-Fi, NFC (Near Field Communication), or RFID (Radio Frequency Identification). This allows the storage unit to obtain and store new display content from the communication unit, and to update the contents of the display content.

(Film-type secondary battery)
Any commercially available product can be used as the film type secondary battery of the present invention. Commercially available products with a thickness of 0.4 mm or less are known. Examples of such film type secondary batteries include the EnerCera (registered trademark) Pouch lineup, which is a chip-type ceramic secondary battery manufactured by Nippon Insulators Co., Ltd. As an example, this film type secondary battery can be arranged next to an integrated circuit and electrically connected by electrical wiring. As the arrangement method and connection method, the methods described in JP-A-2020-072117 and WO2020/241166 can be used.

The film-type secondary battery stores the surplus power supplied by the thin solar cell module, making it possible to maintain and change the displayed content even at night.

(Control board)
The thin, non-powered display device of the present invention has a control board located between the memory-type reflective display unit and the thin solar cell module. This control board has at least a control unit and a power supply circuit, and this power supply circuit supplies the current generated in the memory-type reflective display unit to the thin solar cell module. The thin, non-powered display device of the present invention may also have a memory unit, a communication unit, and a film-type secondary battery in addition to the control unit and the power supply circuit.

The control board is equipped with a control unit, a memory unit, a communication unit, a film-type secondary battery, etc., and has an uneven surface. It may be used as a control board as it is, but in order to make it easier to handle, the unevenness may be absorbed by a spacer to make it flat, and then the entire board may be laminated and integrated. This eliminates the unevenness on the surface, improving workability and handling. For example, WO2019/059305 discloses a manufacturing method for this processing method in which a spacer layer having recesses and holes is laminated and finally pressed to eliminate the unevenness on the surface, and this method may be adopted.

In order to make the control board as thin as possible, it is preferable to select components that are as thin as possible and design them so that they are not stacked. In particular, when mounting larger components such as film-type secondary batteries, it is possible to provide a cutout for the required space in the control board and place the film-type secondary battery there, rather than placing the film-type secondary battery on the control board. In this case, the film-type secondary battery and the control board are electrically connected by a connection circuit. It is preferable to use press processing to increase strength.

(Method of Electrical Connection of Each Functional Part)
In the present invention, the reflective display with memory effect and the control board, and the thin solar cell module and the control board are electrically connected (FIG. 8). As a connection method, a method of electrically connecting the circuit on the control board and the connection circuit of the reflective display with memory effect or the thin solar cell module by resin compression bonding can be mentioned.

Since resin compression bonding requires time-consuming work such as accurate alignment and compression, a connector connection may be used as an alternative connection method. A connector connection is a component that electrically connects the control board by placing a connector on the control board and placing a corresponding connector on the memory-type reflective display unit or thin solar cell module, and joining the two. There is no particular limit to the type of connector, and it may be a type that connects by inserting and clamping a connection circuit (flexible board), a fitting type, etc. By using a connector connection, the memory-type reflective display unit or thin solar cell module can be easily replaced if it becomes defective.

When laminating the control board, it is necessary to process the laminate film so that only the connector part is exposed to the outside, and then press work is performed. This allows electrical connection to the memory-type reflective display unit or thin solar cell module after lamination.

First Embodiment
The thin, non-powered display device according to this embodiment includes a memory-type reflective display section, a thin solar cell module, a fixing section, and a control board on which a power supply circuit and a control section are arranged.

The memory-type reflective display unit used was a color reflective liquid crystal display with a memory-in-pixel function, measuring 88.6 mm×69.4 mm and having a thickness of 1.6 mm, manufactured by Japan Display Inc. Display contents A to C were stored in the memory.

The thin solar cell module used was a solar cell module of the same size as the memory type reflective display unit, made by bonding four solar cell modules of BCS4430B6 manufactured by TDK Corporation, using a film substrate of 44.0 mm x 30.0 mm in size and 0.18 mm in thickness. The size of the solar cell module can be adjusted as needed, so it may be manufactured to order.

A control board (80.0 mm × 60.0 mm, 0.8 mm thick) with a power supply circuit and a control unit was prepared, and the uneven parts were filled with spacers, and the whole was laminated. A clamp-type connector (1.2 mm thick) was used for electrical connection, and the connector part was exposed to the outside.

The memory type reflective display unit and the thin solar cell module were electrically connected to both sides of the control board by connector connections. The memory type reflective display unit was arranged with its display surface facing outward, and the thin solar cell module was arranged with its solar cell facing outward, and the control board and the memory type reflective display unit, and the control board and the solar cell module were fixed with adhesive, respectively. In this way, the main body of the thin non-powered display device was produced.

As the fixing part, a colorless and transparent adhesive sheet (LUCIACS (registered trademark) CS9864UA) (size 90.0 mm x 84.0 mm, thickness 0.1 mm) manufactured by Nitto Denko Corporation was prepared. One side of this adhesive sheet was attached to the thin solar cell module side, and a protective film was left attached to the opposite side. In this way, a thin non-powered display device with a size of 90.0 mm x 84.0 mm and a thickness of 2.7 mm was produced.

The thin, non-powered display device according to this embodiment can then be attached to an ordinary glass window of a commercial facility, for example, as shown in Fig. 2. This allows people inside the commercial facility to view the display content of the thin, non-powered display device. In addition, since the thin, non-powered display device according to this embodiment is thin and does not interfere with the opening and closing of an automatic door, it can also be installed on a transparent structure in an area where an automatic door opens and closes, as shown in Fig. 7.

The thin, non-powered display device according to this embodiment switches between display contents A to C mounted on the memory-type reflective display unit based on a predetermined program during the day when sunlight is shining on the device. The switching is performed by a control unit on the memory-type reflective display unit, but may also be performed by a control unit on a control board. Because the thin, non-powered display device employs a memory-type reflective display unit, it is possible to view any one of the display contents A to C even at night when the device is not shining on the sunlight.

FIG. 6 is a functional block diagram of the main body of the thin non-powered display device of this embodiment.
The reflective display unit with memory 1 includes a display unit 311 and a display memory 312. Display contents A to C to be displayed on the display unit 311 are stored in the display memory 312. Each pixel of the display unit 311 has a display memory, which are collectively referred to as the display memory 312.
The thin solar cell module 2 has a power generation unit 321, and supplies electricity to the display unit 311 and the display memory 312 via a power supply circuit 341 of the control board 4. In addition to the power supply circuit 341, the control board 4 also has a control unit 343, which controls the display unit 311 and the display memory 312. When the amount of external light decreases, the power generation of the power generation unit 321 weakens, making it difficult for the display unit 311 to change the display content. However, since the display unit 311 is a reflective display unit with a memory effect, it is possible to continue displaying the display content as is.

Second Embodiment
A thin, non-powered display device according to another embodiment of the present invention includes a reflective display unit with memory, a thin solar cell module, a fixing unit, a control unit, a storage unit, a communication unit, and a film-type secondary battery.
The difference between the first and second embodiments is that the control board on which the power supply circuit is arranged further includes a control unit, a storage unit, a communication unit, and a film-type secondary battery.

A control board (size 80.0 mm x 60.0 mm, thickness 0.8 mm) equipped with a control unit, a memory unit, a communication unit, and a film-type secondary battery was prepared and used. The film-type secondary battery used was EC382704P-H (27 mm x 38 mm x 0.45 mm, voltage 3.8 V, discharge peak current 10 mA) manufactured by Nippon Insulators, Ltd. The communication unit used was a Bluetooth (registered trademark) module.

The control unit and memory unit were designed in an integrated circuit and mounted on the control board. The communication unit and film-type secondary battery were arranged in a way that did not add to the thickness of the control board by providing a cutout for the necessary space in the control board, and the whole was laminated into a film.

In this manner, a thin non-electrically-supplied display device having a size of 90.0 mm×84.0 mm and a thickness of 2.7 mm was fabricated.

FIG. 8 is a functional block diagram of the main body of the thin non-powered display device of this embodiment.
The reflective display unit with memory 1 and the thin solar cell module 2 are the same as those in the first embodiment. In this embodiment, the control board 4 has a film-type secondary battery 342, a memory unit 344, and a communication unit 345 in addition to the control unit 343 and the power supply circuit 341.

The film type secondary battery 342 stores the surplus power when the power generation unit 321 supplies surplus power. The film type secondary battery 342 then functions as a backup power source when the power generation unit 321 is unable to supply power. This allows the display unit 311 to change the display content even when the power generation unit 321 is unable to supply power, such as at night.

The storage unit 344 can store display contents D to F that cannot be stored in the display memory 312 alone. The display unit 311 can display the display contents D to F stored in the storage unit 344 in addition to the display contents A to C stored in the display memory 312. The control unit 343 can also replace the display contents A to C stored in the display memory with the display contents D to F.

The communication unit 345 can acquire the display contents G to I by wirelessly communicating with the external device 351. Examples of wireless communication means include, but are not limited to, Bluetooth (registered trademark), Wi-Fi, NFC (near-field wireless communication), or RFID (radio frequency identifier). The display contents G to I acquired by the communication unit 345 are stored in the storage unit 344. The control unit 343 can also perform a process of overwriting the display contents stored in the display memory 312 or the storage unit 344 with newly acquired display contents. In this way, the display unit 311 can perform a process to display the newly acquired display contents G to I. This allows the thin non-powered display device to update the display contents.

The communication unit 345 can also update the program that controls the control unit 343 by wirelessly communicating with an external device 351 .

REFERENCE SIGNS LIST 1 Memory-type reflective display unit 2 Thin solar cell module 3 Fixing unit 4 Control board 10 Transparent structure 20 External light 30 Line of sight 100 Thin non-powered display device 311 Display unit 312 Display memory 321 Power generation unit 341 Power supply circuit 342 Film-type secondary battery 343 Control unit 344 Storage unit 345 Communication unit 351 External device 500 Automatic door

Claims (14)

A thin, non-powered display device having an overall thickness of 7 mm or less, the display device comprising a reflective display unit with memory, a thin solar cell module, a fixing unit, a control unit, a storage unit, a communication unit, and a film-type secondary battery,
the memory-type reflective display unit and the thin solar cell module are disposed on both outer flat surfaces of the thin non-powered display device,
The thin non-powered display device includes:
(1) The device is operated using only the thin solar cell module and the film-type secondary battery as power sources,
(2) A control board is provided between the memory-type reflective display unit and the thin solar cell module, and the control board includes the control unit, the storage unit, the communication unit, the film-type secondary battery, and a power supply circuit;
the storage unit stores display content to be displayed on the memory type reflective display unit;
the communication unit communicates with an external device via wireless communication to enable rewriting of the display content;
the fixing portion is disposed on a surface of either the memory-type reflective display unit or the thin solar cell module, and enables the thin non-powered display device to be fixed to a transparent structure without impairing the functions of either the memory-type reflective display unit or the thin solar cell module;
The control unit is mounted on the control board,
the film-type secondary battery is disposed in a space in a cutout provided in the control board and is electrically connected to the control board;
The control board is characterized in that the unevenness of the surface of the control board is absorbed by spacers to make it flat, and the entire board is laminated to be integrated . The thin, unpowered display device according to claim 1, characterized in that the thin, unpowered display device is fixed to one side of a transparent structure, the memory-type reflective display unit is arranged to face the same side, and the fixing part is on the thin solar cell module side. The thin, non-powered display device according to claim 1, characterized in that the thin, non-powered display device is fixed to one side of a transparent structure, the memory-type reflective display unit is arranged to face the opposite side, and the fixing part is on the side of the memory-type reflective display unit. A thin, unpowered display device according to any one of claims 1 to 3, characterized in that the memory-type reflective display unit and the thin solar cell module each occupy 90% or more of the area of the outer plane of the thin, unpowered display device. A thin, non-powered display device according to any one of claims 1 to 4, characterized in that the memory-type reflective display unit is a memory-in-pixel reflective liquid crystal display or a memory-type reflective electronic paper. A thin, unpowered display device according to any one of claims 1 to 5, characterized in that the fixing part is a colorless, transparent adhesive sheet that covers substantially the entire surface of either the memory-type reflective display part or the thin solar cell module. The thin, non-powered display device according to claim 6, characterized in that the fixed portion blocks 99% or more of near-ultraviolet rays with wavelengths of 380 to 200 nm. A thin, unpowered display device as described in claim 1, characterized in that the fixing portion is located on the thin solar cell module side. A thin, unpowered display device as described in any one of claims 1 to 8, characterized in that the communication unit is any one of Bluetooth (registered trademark), Wi-Fi, NFC, and RFID. A thin, non-powered display device as described in any one of claims 1 to 9, characterized in that the transparent structure is an automatic glass door of a commercial store. A thin, unpowered display device as described in any one of claims 1 to 10, characterized in that the control board is connected to at least one of the memory-type reflective display unit and the thin solar cell module via a connector. A thin, non-powered display device according to any one of claims 1 to 11, characterized in that the overall thickness is 3 mm or less. A thin, unpowered display device according to any one of claims 1 to 12, characterized in that color solar cells are used as some of the solar cells in the thin solar cell module, and text or a design is applied to the outer surface of the thin solar cell module by arranging the color solar cells. A thin, unpowered display device according to any one of claims 1 to 13, characterized in that the thin solar cell module employs a see-through solar cell, and text or a design is provided at the back of the see-through solar cell, so that the text or design can be observed through the see-through solar cell.