JP2017116885A - LED display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED display device capable of performing color display, which is excellent in economical efficiency while achieving high-luminance and high-quality display.SOLUTION: In an LED display device 1, a circuit board to mount LED elements 11, 12, 13 is a multilayer LED element substrate in which flexible transparent substrates 21, 22, 23 are stacked in the same number or more as the number of colors of the LED elements 11, 12, 13 constituting unit pixels. On a surface of each flexible transparent substrate 21, 22, 23, LED elements 11, 12, 13 in the same emission color are mounted, while the color differs by each of the flexible transparent substrates 21, 22, 23; and the plurality of LED elements 11, 12, 13 of different emission colors are disposed close to one another in a plan view of the multilayer LED element substrate.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an LED display device. Specifically, the present invention relates to a color display type LED display device using a flexible transparent substrate.

  Various LED display devices such as a dot matrix display device that forms and displays a desired character, symbol, or pattern by selectively emitting LED elements mounted on a plane or a curved surface have been widely used. . For example, a display window is formed on the surface of a housing containing electronic components, an LED display panel in which a plurality of LED elements are arranged in a matrix on a wiring board is provided, and the display control device controls display of the LED elements of the LED display panel. An LED display device or the like configured to do this is known (see Patent Document 1).

  As one form of such an LED display device, in recent years, full-color display can be performed by emitting mixed colors using LED elements capable of high-luminance emission of red (R), green (G), and blue (B). LED display devices that can be used are also spreading (see Patent Documents 2 and 3).

  A full color display type LED display device using the RGB method displays information such as pictures and characters in full color using LED elements capable of emitting light of RGB three primary colors as unit pixels. Such a full-color display type LED display device is, for example, a so-called 3 in 1 type multi-chip LED element in which three color light emitting chips are integrated in one package element as disclosed in Patent Document 2. The pixels can be configured by mounting them in a matrix on a wiring board.

  However, the 3-in-1 type multi-chip LED element generally has a high unit price, and there are many cases where the luminance of each single-color chip is also limited, so that a sufficiently high luminance cannot often be obtained. In particular, when large luminance is required, such as a large display device installed outdoors, it is often impossible to select an LED element with sufficiently high luminance. In this case, each LED element for single-color emission of red (R), green (G), and blue (B) is arranged in a close proximity on the wiring board, a total of three. Thus, a unit pixel for full color display by the RGB method can be configured (see Patent Document 3).

  However, in order to mount each R, G, B single color light emitting LED element on a rigid substrate, which is a general-purpose wiring substrate, it is necessary to form an extremely complicated circuit, and the difficulty and cost of manufacturing. Also rises significantly. In addition, regarding the close placement of these LED elements in the same plane, the distance between the light emitting chips in each LED element that is the light source is due to physical restrictions due to the overall shape and size of each LED element. May not be sufficiently small. If the distance between the light emitting chips in each LED element cannot be made sufficiently small, there arises a problem that the color quality relating to full color display by RGB color mixing cannot be sufficiently improved.

JP 2006-145682 A JP 2010-181721 A JP 2012-212152 A

  The present invention has been made in view of the above situation, and is an LED display device capable of color display, such as a RGB full-color display type LED display device, for example, having high luminance and high quality display. An object of the present invention is to provide an LED display device that is excellent in economic efficiency.

  As a result of intensive research, the present inventors have laminated a plurality of flexible transparent substrates on a wiring board on which a plurality of types and a plurality of LED elements having different emission colors are mounted in a color display type LED display device. The present inventors have found that the above-described problems can be solved by arranging a plurality of types of LED elements in a layer composed of each flexible transparent substrate for each emission color, as a multilayer LED element substrate. Specifically, the present invention provides the following.

  (1) An LED display device that performs multicolor display by configuring a unit pixel capable of multicolor display by combining a plurality of LED elements having different emission colors, and arranging a plurality of the unit pixels. The circuit board on which the element is mounted is a multilayer LED element substrate in which a number of flexible transparent substrates equal to or more than the number of types of colors of the LED elements constituting the unit pixel are laminated, and on the surface of the flexible transparent substrate The LED elements having the same emission color are mounted on the respective flexible transparent substrates, and the plurality of LED elements having different emission colors are close to each other in a plan view of the multilayer LED element substrate. An LED display device constituting the unit pixel capable of multicolor display by being arranged.

  According to the invention of (1), a plurality of LED elements constituting one unit pixel, which is naturally arranged on the same surface of a circuit board, are each flexible transparent substrate layer constituting a multilayer LED element substrate for each emission color. In other words, by arranging them separately in the vertical direction, and arranging them in close proximity to each other in a plan view of the multilayer LED element substrate, that is, in the horizontal direction, as close as possible to color mixing of the luminescent colors. A unit pixel capable of full color light emission by color mixing was constructed. This avoids the limitation of insufficient brightness that has been a problem when using 3 in 1 type elements, and the circuit configuration for each layer is less than when all necessary circuits are formed on the same surface of the circuit board. A much simpler configuration can be achieved. As described above, the quality of the display color can be sufficiently improved while suppressing an increase in production cost for the LED display device capable of performing color display by mixing a plurality of colors. Note that “the emission colors are different” means, for example, that the peak wavelengths of the spectral distribution are different.

  (2) The combination of the LED elements constituting the unit pixel is a combination of three kinds of colors including RGB three primary colors, and the multilayer LED element substrate is a multilayer substrate having a three-layer structure, and the RGB three primary color mixed light The LED display device according to (1), which is capable of full color display.

  The invention of (2) is the LED display device of (1), which is capable of full-color display by RGB three primary color mixed light. By making the material substrate constituting each layer of the multilayer LED element substrate a thin and transparent flexible transparent substrate, it becomes possible to easily perform appropriate separation and arrangement in the vertical direction of each LED element group of RGB. ing. Thereby, it is possible to obtain an LED display device capable of full-color display by the RGB method more economically than in the past while maintaining the display color quality.

  (3) The flexible transparent substrate includes a transparent resin substrate having a light transmittance of not less than 80% and a wavelength of not less than 360 nm and not more than 830 nm, and a metal wiring portion formed on the surface of the transparent resin substrate. The LED display device according to (1) or (2).

  According to the invention (3), in the flexible transparent substrate for LED elements, the support substrate is composed of a resin substrate having extremely excellent translucency with a light transmittance of 80% or more in the visible light region. As a result, the variation in display color quality can be made extremely small, and a full-color display type LED display device capable of displaying with higher quality can be obtained. In addition, the light transmittance of the said wavelength range, ie, visible light transmittance, can be measured by the method based on JISR3212.

  (4) The flexible transparent substrate includes a transparent resin substrate having a haze value of 8% or less and a metal wiring portion formed on the surface of the transparent resin substrate (1) or (2 LED display device described in).

  Invention of (4) WHEREIN: In the flexible transparent substrate for LED elements, a support substrate is comprised with the resin substrate which has the very outstanding translucency whose haze value is 8% or less. As a result, the color design of the unit pixel can be made more easily and strictly, and a full color display type LED display device capable of displaying with higher quality can be obtained. The “haze value” in this specification refers to a haze value (%) measured by a transparency test according to JISK7136.

  (5) The LED display device according to (3) or (4), wherein the metal wiring portion is a copper foil.

  In the invention of (5), the metal wiring part of the flexible transparent substrate in the invention of (3) or (4) is formed of a copper foil having an extremely small electric resistance and high thermal conductivity. Therefore, relative power supply stability and heat dissipation with respect to the coverage of the substrate surface of the metal wiring portion are extremely high. Thereby, it is possible to maintain the electric supply stability and the heat dissipation within a preferable range under a desired circuit design according to various manufacturing conditions and use conditions.

  (6) When the surface coverage by the metal wiring part on the flexible transparent substrate is 2% or more and 10% or less, the substrate aperture ratio of the multilayer LED element substrate is 80% or more (1 The LED display device according to any one of (5) to (5).

  According to the invention (6), in the flexible transparent substrate according to any one of (1) to (5), the surface coverage of the support substrate by the metal wiring portion is set to 10% or less. Visual information arranged on the back side of the display screen as shown in FIG. 6, for example, as shown in FIG. The see-through type LED display device with high visibility can be obtained.

  (7) The LED display device according to any one of (1) to (5), wherein the surface coverage by the metal wiring portion on the flexible transparent substrate is 80% or more and 95% or less.

  In the invention of (7), in the flexible transparent substrate according to any one of (1) to (5), the surface coverage of the support substrate by the metal wiring portion is set to 80% or more. Since the surface coverage of the metal wiring portion serving as a path for releasing heat generated in the LED element is high, the substrate has excellent heat dissipation and low electrical resistance. Thereby, the power consumption of each LED element is small, and the variation in light emission luminance can also be suppressed. Further, deterioration of peripheral members such as a substrate due to heat can be prevented and the product life can be extended.

  (8) The LED element is a chip-type LED element for surface mounting, and light emission of the LED element which is arranged close to each other in a plan view of the multilayer LED element substrate and constitutes the unit pixel The chips are arranged at positions where they do not overlap in the plan view, and parts of the LED elements other than the light emitting chips are arranged at positions where they overlap each other in the plan view. The LED display device according to any one of (1) to (7).

  The invention of (8) escapes from restrictions due to the overall shape and size of the LED element when the surface-mounted chip type LED element is mounted close to the same surface of the substrate (see FIG. 5A), The distance in the horizontal direction between the light emitting chips in the unit pixel is further reduced from the limit due to the above-mentioned restrictions. Thereby, the quality of full color display by color mixture can be further improved.

  (9) The LED display device according to any one of (1) to (8), wherein the multilayer LED element substrate has a thickness of 10 mm or less.

  According to the invention of (8), the LED display device according to any one of (1) to (8) can enjoy the advantages of adopting a flexible substrate as a substrate material, It is a thing. The demerit of the vertical deviation of the arrangement position of the LED elements can be minimized. In addition, the degree of freedom in installation conditions is significantly increased by reducing the thickness and weight.

  ADVANTAGE OF THE INVENTION According to this invention, it is an LED display apparatus which can display multicolor, Comprising: While being able to display high brightness and high color quality, the LED display apparatus excellent in economical efficiency can be provided.

It is the top view by the side of the information display surface of the LED display apparatus of this invention, and its partial enlarged view. It is an expanded sectional view of the cross section of the AA part of FIG. 1, and is drawing with which it uses for description of the arrangement | positioning aspect in the vertical direction of the LED element in the LED display apparatus of this invention. It is a disassembled perspective view which shows the structure of the LED display apparatus of this invention typically. It is a top view which shows typically an example of the mounting aspect to the wiring part of 3 LED elements which comprise 1 unit unit pixel, and a circuit structure in the LED display apparatus of this invention. It is a top view which shows typically the more preferable mounting aspect to the wiring part of the three LED elements which comprise a unit pixel. It is a front view showing typically a see-through type LED display device which is one of the embodiments of the LED display device of the present invention.

  Hereinafter, the LED display device of the present invention and the multilayer LED element substrate used in the LED display device will be sequentially described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention.

<LED display device>
The LED display device of the present invention is a color display device in which a plurality of unit pixels, which are display units capable of emitting light in any multicolor, preferably full color, are mounted on a multilayer LED element substrate. The LED display device can display a desired character or image in color by controlling the light emission of the unit pixel. In particular, the LED display device 1 according to the present invention shown in FIG. 1 is a display device capable of full-color display because the unit pixel 10 is composed of RGB three-color LED elements 11, 12, and 13. is there.

  As shown in FIG. 6, the LED display device of the present invention can also be implemented as a see-through type LED display device 1A by taking advantage of the transparency of the substrate on which the LED elements are mounted. As shown in FIG. 6, for example, the see-through type LED display device 1A is assumed to be disposed and used on the front surface of a show window or the like. In this case, a person positioned on the front side of the LED display device 1A can visually recognize the visual information on the back side of the LED display device 1A simultaneously with the recognition of the information displayed on the LED display device 1A. .

  When the LED display device of the present invention is used as a see-through type LED display device 1A, as described in detail later, the flexible transparent substrate constituting each layer of the multilayer LED element substrate constituting the LED display device is the metal The surface coverage by the wiring part is preferably 2% or more and 10% or less. Since the surface coverage by the metal wiring part is 2% or more and 10% or less, the substrate opening ratio of the multilayer LED element substrate is 80% or more and 95% or less, and the LED display device has a sufficient see-through function. Can be made. The “substrate aperture ratio of the multilayer LED element substrate” refers to a ratio defined as an area ratio of a portion of the surface of the substrate aperture ratio of the multilayer LED element substrate where the metal wiring portion does not exist in plan view. Say it.

[Unit pixel]
The unit pixel 10 is configured by a combination of a plurality of monochromatic light emitting LED elements arranged in proximity. The specific number of the plurality of LED elements constituting one unit pixel 10 is not limited to a specific number. For example, a combination of three LED elements, a red (R) LED element 11, a green (G) LED element 12, and a blue (B) LED element 13, provides a full-color RGB system. An example in which the unit pixel 10 capable of emitting light is configured can be given as a preferable example. Hereinafter, the LED display device 1 in which the unit pixel 10 constitutes one unit pixel 10 by combining three LED elements of RGB will be described in detail as an example of a preferred embodiment of the present invention.

(LED element)
In the LED display device 1, a chip-type LED element for surface mounting can be preferably used as the LED element. A chip-type LED element is a P-type semiconductor and an N-type semiconductor bonded to a fine packing made of resin, etc., in which electrodes (anode and cathode) and a reflector for mounting directly on a circuit are integrated. It is an element having a built-in diode-type light-emitting chip as a light emitter. The unit pixel 10 can be configured by mounting this chip-type LED element at a predetermined position on the flexible transparent substrates 21, 22, and 23 constituting the multilayer LED element substrate 20 for each emission color.

  The LED elements 11, 12, and 13 include a red LED element 11 including a light emitting chip 111 that emits red light, a green LED element 12 including a light emitting chip 121 that emits green light, and a light emitting chip 131 that emits blue light. A combination with the blue LED element 13 (see FIGS. 4 and 5) is preferably used. These LED elements 11, 12, 13 of each color are based on a certain arrangement pattern so that one unit pixel 10 can be formed by a combination of a total of three for each color, and the multilayer LED element substrate 20. To be implemented.

[Multilayer LED element substrate]
As shown in FIGS. 2 and 3, in the LED display device 1, a multilayer LED element substrate 20 is used as a circuit board for mounting the LED elements 11, 12, and 13. The multilayer LED element substrate 20 has a multilayer structure in which the number of flexible transparent substrates (21, 22, 23) equal to or more than the number of types of light emission colors (three types in the present embodiment) of the LED elements to be mounted are laminated. Circuit board. 2 and 3, the LED element is composed of three types of LED elements 11, 12, and 13 in three colors of R, G, and B, and a multilayer LED element in which three flexible transparent substrates 21, 22, and 23 are laminated. A substrate 20 is used. These LED elements 11, 12, and 13 are separately disposed on each layer composed of the flexible transparent substrates 21, 22, and 23.

  There is no special limitation on the size of the multilayer LED element substrate 20. However, since a flexible substrate is used as the substrate material, the degree of freedom of size processing of the substrate is high, so that it can be preferably used for a large-sized LED display device that is assumed to be used outdoors. For example, even in an LED display device having a large display screen with a diagonal length of 32 inches or more, more preferably 65 inches or more, the multilayer LED element substrate 20 can be preferably used as a circuit board.

  As shown in FIG. 2 and FIG. 3, a plurality of LED elements 11, 12, and 13 that emit light different from each other arranged to form one unit pixel 10 are multilayer LED elements for each color LED element. It is mounted on the surfaces of flexible transparent substrates 21, 22, and 23 that constitute the substrate 20. For example, in the example of FIGS. 2 and 3 in which the flexible transparent substrates 21, 22, and 23 are stacked in this order from the display surface side, the red LED elements 11 are all green on the flexible transparent substrate 21. The LED elements 12 are all disposed on the flexible transparent substrate 22, and the blue LED elements 13 are all disposed on the flexible transparent substrate 23. The arrangement of the LED elements 11, 12, and 13 makes it possible to configure the unit pixel 10 capable of emitting high-quality full color light. Note that the arrangement order of the RGB elements in the vertical direction is not necessarily limited to this order.

  The difference in the arrangement position in the vertical direction between the LED elements having different emission colors that are separately arranged on the three layers of the flexible transparent substrates 21, 22, and 23 is the light emission performance of the mounted LED elements, for example, luminance and light emission. Although it depends on directivity, it is generally preferable that the difference in vertical position of the surface of each LED element (for example, LED elements 11 and 12 in FIG. 2) on the light emitting surface side is within 10 mm. For example, if the thickness of each LED element is about 1 mm or more and 3 mm or less, the thickness of each flexible transparent substrate 21, 22, 23 is set in a range of 50 μm or more and 200 μm or less, as described above, between LED elements. The difference in the arrangement position in the vertical direction can be about 10 mm. Although it is practically impossible to form a substrate having this thickness with a conventional general-purpose rigid substrate, a multilayer LED element substrate within the above thickness range can be easily formed by using a flexible substrate as the substrate material. Can be formed.

  In the vertical direction, the plurality of types of LED elements are distributed in the vertical direction inside the multilayer LED element substrate 20 for each emission color as described above, but as shown in FIGS. In the horizontal direction, the pair of LED elements 11, 12, and 13 are arranged so as to be sufficiently close to each other in plan view to the extent that they can constitute a single unit pixel 10 and exhibit a full color display function. Is done. Regarding the distance in plan view between the LED elements constituting one unit pixel 10, in the case of using a chip-type LED element, it is assumed that the difference in the vertical position of the LED elements is within 10 mm as described above. In this case, the distance between the centers of the light emitting chips (for example, the light emitting chips 111 and 121 in FIG. 2) in plan view is preferably within 10 mm.

  As shown in FIG. 5, when the LED element is a chip-type LED element, the LED elements 11, 12, and 13 constituting one unit pixel 10 are arranged in the plan view of the multilayer LED element substrate 20. Each of the light emitting chips 111, 121, and 131 needs to be arranged at a position where they do not overlap each other in the plan view. Furthermore, in the conventional product, as shown in FIG. 5 (a), the portions other than the light emitting chips of the LED elements 11, 12, and 13, specifically, the electrodes (anode and cathode), the reflector and the like described above are integrated. It was necessary to separate and arrange each LED element so that the outer edge of the package body did not interfere with each other. However, in the LED display device 1, as shown in FIG. 5B, a part of each LED element other than the light emitting chip can be arranged at a position where they overlap each other in the plan view (unit pixel). 10A). As a result, the distance between the light emitting chips of the LED elements can be made shorter than the conventional product by the overlapping portion, and the color quality of the color light emission for each unit pixel can be further improved. Further, by reducing the outer edge of each unit pixel 10, the pitch between the pixels 10 can be reduced, the number of pixels per unit area of the display screen can be increased, and the display quality can be improved.

  In addition, as shown in FIG. 4, in the multilayer LED element substrate 20, the metal wiring portions 30 (31, 32, and 33) for mounting the LED elements are flexible on which the LED elements 11, 12, and 13 are stacked. It is formed on each surface of the transparent substrates 21, 22 and 23. As shown in FIG. 4, for example, the metal wiring portion 33 on which the blue LED element 13 disposed on the lowermost layer side is mounted is placed in a direction perpendicular to the light emitting chips of other color LED elements in plan view. Even if it overlaps, it does not become an obstacle of light emission from other LED elements. However, for example, with respect to the metal wiring portion 32 on which the green LED element 12 is mounted, as shown in FIG. 4, the position overlapping the light emitting chip 131 of the LED element 13 disposed below the LED element 13 is avoided. To form.

  The multilayer LED element substrate 20 can be manufactured by stacking and integrating a plurality of flexible transparent substrates by a method of stacking or stacking the LED elements 11, 12, and 13.

(Flexible transparent substrate)
As the flexible transparent substrates 21, 22, and 23 that form each layer of the multilayer LED element substrate 20, a conventionally known flexible substrate is used as long as the metal wiring portion 30 is formed on the surface of a resin substrate having transparency. It can be used as appropriate. Also, normally, the flexible transparent substrates 21, 22, and 23 are covered by an insulating protective film (not shown) except for the mounting area of the LED elements 11, 12, and 13 on the support substrate and the metal wiring part 30. Are stacked.

  The flexible transparent substrates 21, 22, and 23 need to be circuit substrates having “transparency”. However, it is not always necessary that the whole is transparent. At least the range necessary for visually recognizing the light emitted from the unit pixel 10 from the outside may be “transparent”. In the present specification, in the flexible substrate, “having transparency” means that the light transmittance in the visible light region (wavelength 360 nm or more and 830 nm or less) of the portion is 80% or more, preferably 90% or more. Shall be said. If the light transmittance is 80% or more, the variation in display color quality can be made extremely small, and a full-color display type LED display device capable of high-quality display can be obtained. Furthermore, if the light transmittance is 90% or higher, it is possible to display a higher quality and, more likely, higher contrast and sharper video.

  Further, as another index of the transparency of the flexible substrate, the haze value in the same part as described above is preferably 8% or less, more preferably 4% or less. If the haze value is 8% or less, various emission colors from each unit pixel arranged on the lower layer side can be recognized as different colors. Further, if the haze value is 4% or less, it is possible to make the viewer recognize the display without any substantial attenuation in terms of the full color display quality by the RGB method.

  Preferred examples of the resin used as the support substrate for the flexible transparent substrates 21, 22, and 23 that require transparency, heat resistance, insulation, etc. include polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), non- Crystalline polyarylate, polysulfone, polyethersulfone, polyetherimide, fluororesin, liquid crystal polymer and the like can be mentioned. Among these, polyethylene naphthalate (PEN) whose heat resistance and dimensional stability are improved by performing a heat resistance improvement treatment such as an annealing treatment can be particularly preferably used.

  The thickness of the support substrate of the flexible transparent substrates 21, 22, and 23 is not particularly limited, but the LED element separation arrangement in the vertical direction when stacked as the multilayer LED element substrate 20 is within the range of the difference in the vertical position described above. From the viewpoint of maintaining the thickness, it is preferably about 50 μm or more and 200 μm or less. Also, the thickness is preferably within the above-mentioned thickness range from the viewpoint of maintaining good productivity when manufacturing by the roll-to-roll method.

  On the surface of the flexible transparent substrates 21, 22, and 23, a metal wiring portion 30 is formed by a conductive base material such as a metal foil. The metal wiring portion 30 has a function of supplying electricity by conducting a necessary current through the LED elements, and also functions as a heat radiating portion in the flexible transparent substrates 21, 22, and 23.

  In order to maximize the see-through function of the flexible transparent substrate, it is conceivable to form the metal wiring portion with a transparent electrode. However, the transparent electrode is a copper that has been widely used in the past in terms of reliability and manufacturing cost in accurately applying a stable and uniform voltage to the entire circuit disposed on the entire surface of the LED element substrate. Inferior to metal wiring such as foil. In order to promote heat dissipation from the substrate, it is preferable that the metal wiring has high thermal conductivity. In this respect, the copper foil is clearly superior. The tendency of the metal foil to be dominant becomes more remarkable as the screen size of the display surface increases. Therefore, in the LED display device 1 of the present invention, the metal wiring part is more preferably a metal having a high thermal conductivity such as copper even when used as a see-through type.

The thermal conductivity λ of the metal constituting the metal wiring portion 30 is preferably 200 W / (m · K) or more and 500 W / (m · K) or less, and preferably 300 W / (m · K) or more and 500 W / (m · K) or less. More preferred. The electric resistivity R of the metal constituting the metal wiring portion 30 is preferably 3.00 × 10 ⁻⁸ Ωm or less, and more preferably 2.50 × 10 ⁻⁸ Ωm or less. Here, the measurement of the thermal conductivity λ can use, for example, a thermal conductivity meter QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd., and the measurement of the electrical resistivity R can be performed, for example, a 6517B type electrometer manufactured by Keithley. Can be used. According to this, for example, in the case of copper, the thermal conductivity λ is 403 W / (m · K), and the electrical resistivity R is 1.55 × 10 ⁻⁸ Ωm. Thereby, the light emission variation between LED elements becomes small, the stable light emission as an LED display device is attained, and the lifetime of an LED element is also extended.

  In the flexible transparent substrates 21, 22, and 23, the LED display device 1 is arranged such that the substrate surface coverage by the metal wiring portion 30 on one surface of the support substrate is 40% or less, preferably 10% or less. Can exhibit a sufficient see-through function as the see-through type LED display device 1A as shown in FIG.

  Examples of the metal constituting the metal wiring part 30 include metal foils such as aluminum, gold, silver, and copper. The thickness of the metal wiring part 30 may be appropriately set according to the magnitude of current resistance required for the flexible transparent substrates 21, 22, and 23, and is not particularly limited. However, as an example, the thickness is 10 μm or more and 50 μm or less. Thickness is mentioned. From the viewpoint of improving heat dissipation, the thickness of the metal wiring part 30 is preferably 10 μm or more. Also, if the metal layer thickness is less than the above lower limit, the influence of the heat shrinkage of the support substrate is large, and the warp after the processing is likely to increase during the solder reflow process. From this viewpoint, the thickness of the metal wiring part 30 is It is preferable that it is 10 micrometers or more. On the other hand, when the thickness is 50 μm or less, sufficient flexibility of the flexible transparent substrates 21, 22, and 23 can be maintained, and a reduction in handling property due to an increase in weight can be prevented.

  The metal wiring part 30 is not only configured on one surface of each flexible transparent substrate 21, 22, 23, but also formed on both surfaces of each flexible transparent substrate 21, 22, 23. Good. By using a multilayer transparent substrate having a multilayer circuit composed of the metal wiring section 30 having a total of six layers, that is, a variety of displays such as a full-color dot matrix display is possible. Become. In this case, the circuit configuration can be further simplified by using an LED element with a driver IC as the LED element.

  An insulating protective film is laminated as necessary on the other portions except the portion where electrical connection on the surface of the metal wiring portion 30 and the support substrate is required. The insulating protective film is required to be able to maintain the transparency of the flexible transparent substrates 21, 22, and 23 like the support substrate. The light transmittance and other optical characteristics required for the insulating protective film are the same as those required for the support substrate, and the light transmittance in the visible light region is 80% or more, preferably 90% or more.

  In the LED display device 1, a fine gap is formed between the flexible transparent substrates 21, 22, and 23, and the gap portion can be filled with a transparent resin sealing material as necessary. preferable.

  It does not specifically limit about the manufacturing method of a flexible transparent substrate, It can manufacture with the manufacturing method of the electronic substrate using a conventionally well-known flexible substrate. An example of a specific manufacturing method will be described below. First, the metal wiring part 30 such as a copper foil used as the material of the metal wiring part 30 is laminated on the surface of the support substrate by a dry lamination method to obtain a laminated body used as the material of the flexible transparent substrates 21, 22, and 23. Next, the metal wiring part 30 of a desired shape can be formed by performing a well-known etching process with respect to said laminated body.

  In addition, joining of the LED elements 11, 12, and 13 to the metal wiring part 30 in the flexible transparent substrates 21, 22, and 23 can be preferably performed by soldering via a solder layer. This solder bonding can be performed by a reflow method or a laser method. In the reflow method, the LED elements 11, 12, and 13 are mounted on the metal wiring part 30 via solder, and then the flexible transparent substrate is transported into the reflow furnace, and the metal wiring part 30 has a predetermined temperature in the reflow furnace. In this method, solder paste is melted by blowing hot air, and the LED elements 11, 12, and 13 are soldered to the metal wiring portion 30. The laser method is a method of soldering the LED elements 11, 12, and 13 to the metal wiring portion 30 by locally heating the solder with a laser.

  After forming the metal wiring part 30, an insulating protective film is further laminated. This lamination can be performed by a known method. Depending on the material to be employed, various laminating methods such as screen printing, dry lamination, thermal lamination, and the like can be used. The LED display device 1 can be manufactured through the above steps.

DESCRIPTION OF SYMBOLS 1 LED display apparatus 1A See-through type LED display apparatus 10 Unit pixel 11, 12, 13 LED element 111, 121, 131 Light emitting chip 20 Multilayer LED element board | substrate 21, 22, 23 Flexible transparent substrate 30 (31, 32, 33) Metal Wiring part

Claims (9)

A unit pixel capable of multicolor display is configured by a combination of a plurality of LED elements having different emission colors, and an LED display device that performs multicolor display by arranging a plurality of the unit pixels,
The circuit board on which the LED element is mounted is a multilayer LED element board in which flexible transparent substrates of the same number or more as the number of types of colors of the LED elements constituting the unit pixel are laminated,
On the surface of the flexible transparent substrate, LED elements of the same luminescent color, which are different for each flexible transparent substrate, are mounted,
A plurality of the LED elements having different emission colors are arranged close to each other in plan view of the multilayer LED element substrate, thereby constituting the unit pixel capable of multicolor display. . The combination of LED elements is a combination of three types including RGB three primary colors,
The multilayer LED element substrate is a multilayer substrate having a three-layer structure,
The LED display device according to claim 1, wherein full-color display using RGB three primary color mixed light is possible.   The said flexible transparent substrate is comprised including the transparent resin substrate whose light transmittance of wavelength 360nm or more and 830nm or less is 80% or more, and the metal wiring part formed in the surface of the said transparent resin substrate. The LED display device according to 1 or 2.   3. The LED according to claim 1, wherein the flexible transparent substrate includes a transparent resin substrate having a haze value of 8% or less and a metal wiring portion formed on a surface of the transparent resin substrate. Display device.   The LED display device according to claim 3, wherein the metal wiring portion is a copper foil.   6. The surface area coverage by the metal wiring portion on the flexible transparent substrate is 2% or more and 10% or less, so that the substrate opening ratio of the multilayer LED element substrate is 80% or more. The LED display device according to any one of the above.   The LED display device according to any one of claims 1 to 5, wherein a surface coverage by the metal wiring portion on the flexible transparent substrate is 80% or more and 95% or less. The LED element is a chip-type LED element for surface mounting,
The light emitting chips of the LED elements that are arranged close to each other in the plan view of the multilayer LED element substrate and constitute the unit pixel are arranged in positions that do not overlap in the plan view, The LED display device according to any one of claims 1 to 7, wherein a part of the LED element other than the light emitting chip is disposed at a position overlapping each other in the plan view.   The LED display device according to claim 1, wherein the multilayer LED element substrate has a thickness of 10 mm or less.

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