JP2016122820A - Substrate for LED element and LED display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mitigate the risk of bending damage of an LED element and a metal wiring part due mainly to the flexibility of a resin substrate in an LED-mounted module that uses a flexible wiring substrate.SOLUTION: An LED-mounted module formed by mounting an LED element on a flexible wiring substrate is made to satisfy the condition that "given imaginary two-dimensional XY coordinates in which the longitudinal direction or the longer axis direction of a resin substrate is defined as the X axis direction, each of other LED elements belonging to an adjacent LED element group 21a-d is arranged such that the centroid thereof is positioned offset from the X axis and the Y axis of the two-dimensional XY coordinates, for which the centroid of a center LED element 20 is as the origin."SELECTED DRAWING: Figure 4

Description

  The present invention relates to an LED element substrate and an LED display device using the same. More specifically, an LED element substrate that can be used as a backlight light source of an LED display device by mounting a light emitting diode (LED) element, and that can contribute to an improvement in productivity of the LED display device; The present invention relates to an LED display device using the same.

  In recent years, as an alternative to conventional cathode ray tube type monitors, it is possible to meet the demands for lower power consumption, larger and thinner devices, and LEDs such as liquid crystal televisions and liquid crystal displays that use LED elements as backlight sources. The spread of display devices is progressing rapidly.

  In order to mount an LED element as a light source in these display devices, various types of LED element substrates each including a support substrate and a wiring portion are usually used. And the laminated body which mounts the LED element on these board | substrates (this laminated body member is hereafter called "LED mounting module") is the light source of various display apparatuses, such as said liquid crystal television, That is, it is widely used as an LED backlight.

  These display devices are required to improve the luminance of the light source in order to improve the image quality. However, an increase in the amount of heat generated from the LED element due to the improvement in luminance leads to an increase in power consumption and a decrease in the light emission capability of the LED element. Therefore, the LED mounting module is strongly required to improve the heat dissipation as well as the luminance. This demand for improvement in heat dissipation is a particularly urgent issue in displays and the like for liquid crystal televisions and the like that have been increasing in size in recent years.

  As a form of mounting the LED element for improving the heat dissipation, for example, a method of directly mounting the LED element on a metal surface of a metal base substrate has been proposed (see Patent Document 1). However, this method has a low degree of freedom in design because the metal base is plate-like, and the productivity is low because batch production is performed for each substrate.

  On the other hand, a substrate in which a metal circuit is formed on a flexible resin substrate (hereinafter referred to as a “flexible wiring substrate”), which is a metal layer provided separately from a conduction circuit only to exhibit a heat dissipation function (Patent Document 2) or a circuit board in which a thermal connection part, which is a part divided from a circuit for conduction, is separately formed (Patent Document 3).

  However, in these flexible wiring boards, the flexibility of the base resin and the flexural modulus of the base resin and the metal wiring portion in any of the steps until it is incorporated into the final product such as an LED display device. Due to the difference, there are some cases in which the LED display device or the like is fatally damaged, such as bending of the substrate that cannot be restored or damage of the LED element mounting portion. This has been one of the factors that hinder the improvement of the productivity of LED display devices.

JP 2009-81194 A JP 2012-59867 A Special table 2013-522893

  The present invention has been made in view of the situation as described above, and an LED element or a metal wiring portion mainly caused by the flexibility of a base resin in an LED mounting module using a flexible wiring board. The purpose is to reduce the risk of bending damage.

  As a result of intensive studies, the present inventors have determined that the LED element placement is unique to the present application in the LED mounting module in which the LED element is mounted on a flexible wiring board in which a metal wiring part is formed on a flexible resin film. The inventors have found that the above problem can be solved by using a specific arrangement, and have completed the present invention. Specifically, the present invention provides the following.

(1) An LED mounting module in which LED elements are mounted in a matrix on a flexible wiring board in which a metal wiring portion is formed on a resin substrate made of a flexible resin. An LED mounting module, which is disposed at a position that satisfies the conditions of a) and (b).
(A) Arbitrary one LED element is set as a central LED element, and among the other LED elements arranged around the central LED element, the one closest to the central LED element is the fourth closest in order. When selecting up to one, four other LED elements selected in this way are referred to as adjacent LED element groups.
(B) Assuming a two-dimensional XY coordinate in which the center of gravity of one LED element on the flexible wiring board is the origin and the longitudinal direction or the long axis direction of the resin substrate is the X axis direction, any of the LED elements belonging to the adjacent LED element group The other LED elements are also arranged at positions where their centroids deviate from the X and Y axes of the two-dimensional XY coordinates.

  (2) The LED according to (1), wherein the resin substrate is made of a single flexible resin having a diagonal length of 32 inches or more, and 100 or more LED elements are mounted in a substantially matrix shape. Mounting module.

  (3) The LED display apparatus which uses the LED mounting module as described in (1) or (2) as a backlight light source.

  According to the present invention, an LED mounting module in which an LED element is mounted on a flexible wiring board, and the risk of bending damage of the LED element or metal wiring portion mainly due to the flexibility of the base resin is reduced. A mounting module can be provided.

It is a top view which shows typically the whole structure of the metal wiring part of the board | substrate for LED elements of this invention. It is a fragmentary sectional view of the LED mounting module formed by mounting an LED element on the element substrate of the present invention. It is a top view which shows typically the LED mounting module formed by mounting an LED element on the board | substrate for LED elements of this invention. It is the top view which showed typically arrangement | positioning of an LED element in order to use for description of the arrangement condition of the LED element in the LED mounting module of this invention. It is the top view which showed typically another example of arrangement | positioning of an LED element in order to use for description of the arrangement condition of the LED element in the LED mounting module of this invention. It is the top view which showed typically the unfavorable arrangement | positioning of an LED element in order to use for description of the arrangement condition of the LED element in the LED mounting module of this invention. It is a top view which shows an example of a structure of the metal wiring part of the board | substrate for LED elements which can be preferably used for the LED mounting module of this invention. It is a top view which shows another example of a structure of the metal wiring part of the board | substrate for LED elements which can be preferably used for the LED mounting module of this invention. It is a perspective view which shows typically the outline of the layer structure of the LED display apparatus which uses the LED mounting module of this invention.

  Hereinafter, the LED mounting module of the present invention will be described together with embodiments of an LED element substrate, which is a flexible substrate that can be preferably used in the module, and an LED display device. 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. For example, the following LED element substrate 1 can be preferably used as a constituent member of the LED mounting module of the present invention, but the flexible wiring board constituting the present invention is not limited thereto. Any other general flexible wiring board is within the scope of the present invention as long as the LED elements are arranged on the flexible wiring board in a manner satisfying the arrangement conditions unique to the present invention described later. .

<LED element substrate>
As shown in FIGS. 1 and 2, the LED element substrate 1 has a conductive metal wiring portion 13 made of a metal foil on a surface of a resin substrate 11 made of a flexible resin with an adhesive layer 12 interposed therebetween. Is formed. The metal wiring portion 13 is formed on the resin substrate 11 in such a manner that the LED elements 2 arranged in a matrix shape or a substantially matrix shape can be conducted. Details of conditions relating to the arrangement of the LED elements 2 which are characteristic parts of the present invention will be described later.

  Further, as shown in FIG. 2, the LED element substrate 1 has an insulating protective film 15 made of thermosetting ink or the like formed on the resin substrate 11 and the metal wiring portion 13. In order to improve the migration resistance of the LED element substrate 1, the insulating protective film 15 is formed on the entire surface of the metal wiring portion 13 except for the connection portion for mounting the LED element 2 and on the resin substrate 11. It is formed so as to cover substantially the entire surface of the surface where the metal wiring portion 13 is not formed.

  Further, as shown in FIG. 2, the LED element substrate 1 has a reflective layer 16 made of a white resin or the like further laminated on an insulating protective film 15 on the resin substrate 11 and the metal wiring portion 13. It is preferable that In particular, when the LED mounting module 10 in which the LED element 2 is mounted on the LED element substrate 1 is used as a backlight of the LED display device 100 as shown in FIG. 9, the reflective layer 16 is used as the outermost surface of the LED mounting module. In general, it is essential to arrange them. However, it is also possible to provide the insulating protective film 15 with a reflective function, thereby ensuring the necessary reflective function with the insulating protective film without installing a reflective layer.

  As shown in FIG. 2, the LED element substrate 1 is an LED mounting module 10 in which the LED element 2 is mounted on the metal wiring portion 13 in a conductive manner via the solder layer 14. The LED mounting module 10 can be preferably used as a backlight light source of an LED display device such as an LED liquid crystal television.

  The size of the LED element substrate 1 is not particularly limited. For example, the present invention can be preferably applied to a large LED mounting module in which the length of the diagonal line d is 32 inches or more and 100 or more LED elements 2 are mounted in a matrix. FIG. 3 is an example of a mounting mode of the LED elements 2 on the LED element substrate 1. FIG. 3 shows an example in which 40 LED elements 2 in the X direction and 30 LED elements 2 in total are mounted. Show. The planar shape of the LED element substrate of the present invention is not necessarily limited to a rectangular shape. In this specification, “the length of the diagonal line is 32 inches or more” means, for example, the length of the major axis when the LED element substrate is elliptical.

[Resin substrate]
As a material of the resin substrate 11, a flexible thermoplastic resin formed into a sheet shape can be used. Here, the sheet form is a concept including a film form, and there is no difference between the two in the present invention as long as both are flexible.

  The thermoplastic resin used as the material for the resin substrate 11 is required to have high heat resistance and insulation. As such a resin, a polyimide resin (PI) excellent in heat resistance, dimensional stability during heating, mechanical strength, and durability can be used. In addition, various other thermoplastic resins whose heat resistance and dimensional stability are improved by performing a heat resistance improving process such as an annealing process can also be used. For example, polyethylene naphthalate (PEN) that has been provided with necessary and sufficient heat resistance and dimensional stability by annealing treatment. Further, PET or the like whose flame retardancy is improved by adding a flame retardant inorganic filler or the like can be selected as a material resin for the substrate film.

  The heat resistance of the thermoplastic resin forming the resin substrate 11 has been improved by the annealing treatment so that the thermal shrinkage starting temperature is equal to or higher than the thermosetting temperature of the thermosetting ink forming the insulating protective film 15. It is preferable to use one. For example, when the insulating protective film 15 is formed of a thermosetting ink having a thermosetting temperature of about 80 ° C., the heat shrinkage starting temperature of PEN, which is usually about 80 ° C., is about 100 ° C. by annealing. Can be improved. Thereby, it is possible to form the insulating protective film 15 having sufficient heat resistance, strength, and insulation while avoiding minute heat damage of the resin substrate 11.

  In this specification, “thermal shrinkage start temperature” means that a sample sheet made of a thermoplastic resin to be measured is set in a TMA apparatus, a load of 1 g is applied, and the temperature is increased to 120 ° C. at a temperature rising rate of 2 ° C./min. Measure the amount of shrinkage (in%) at that time, output this data and record the temperature and amount of shrinkage, read the temperature that deviates from the 0% baseline due to shrinkage, and heat shrink the temperature This is the starting temperature. In addition, the “thermosetting temperature” in the present specification is the measurement and calculation of the temperature at the rising position of the thermosetting reaction when the thermosetting resin to be measured is heated, and that temperature is the thermosetting temperature. .

Regarding the insulating property of the resin substrate 11, for example, when the LED element substrate 1 is used as a backlight of an LED display device, the insulating property required for the LED element substrate 1 when integrated as an LED display device. It is calculated | required that it is resin which has volume specific resistivity which can provide. In general, the volume resistivity of the resin substrate 11 is preferably 10 ¹⁴ Ω · cm or more, and more preferably 10 ¹⁸ Ω · cm or more.

  The thickness of the resin substrate 11 is not particularly limited, but is preferably about 10 μm or more and 100 μm or less from the viewpoint of heat resistance and insulation, and a balance between manufacturing costs. 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.

  The size of the resin substrate 11 is not particularly limited. However, the LED element substrate can be made of, for example, a single resin film having a diagonal length of 32 inches or more. In this specification, the term “single resin film” means that the resin film is not a collection of a plurality of resin films or a joined body in which they are physically joined, but a single sheet film. It means that it is a resin film. Such a single large film can be produced by a special extrusion apparatus capable of producing a film outside the conventional standard range.

[Adhesive layer]
The metal wiring part 13 is preferably joined to the surface of the LED element substrate 1 by a dry laminating method with the adhesive layer 12 interposed therebetween. As the adhesive forming the adhesive layer 12, a known resin adhesive can be appropriately used as long as it has heat resistance at the thermosetting temperature of the thermosetting ink forming the insulating protective film 15. Of these resin adhesives, urethane-based, polycarbonate-based, or epoxy-based adhesives can be particularly preferably used.

[Metal wiring section]
The board | substrate for LED elements can further reduce a bending risk also by limiting the shape and arrangement | positioning of the metal wiring part to an original aspect.

  The metal wiring part 13 is a wiring pattern composed of a polygonal conductive plate part 131 formed of a conductive base material on the surface of the LED element substrate 1. The shape of the conductive plate portion 131 in plan view may be a convex polygon such as a regular polygon as long as it is a polygonal shape capable of conducting between the LED elements 2 arranged in a matrix. A concave polygon as shown in FIG.

  As shown in FIG. 1 and the like, the metal wiring portion 13 is a bonding portion of the LED element 2 to the metal wiring portion 13 so that the LED element 2 can be conducted in both XY directions on the matrix. It is preferable that the arrangement is repeated. As shown in FIG. 2, the basic unit of mounting refers to a portion including a pair of adjacent conductive plate portions 131 on the LED element substrate 1 and an insulating slit portion 132 that is a gap portion therebetween. More specifically, the insulating slit portion 132 is a non-formed portion of the metal wiring portion 13 in the LED element substrate and is a non-conductive portion between the pair of adjacent conductive plate portions 131.

  As shown in FIG. 1, the metal wiring portion 13 is a connector wiring for connecting between the conductive plate portions 131 arranged in different rows or columns in the matrix arrangement in addition to the above-described basic unit of mounting. 133 and a terminal 134 for electrical connection between the LED mounting module 10 and an external power source or the like at the end of the row or column. In the LED element substrate 1, the degree of freedom in designing the arrangement and combination of the conductive plate part 131, the connector wiring 133, and the terminal 134 constituting the metal wiring part 13 is high. Either a series connection or a parallel connection is possible, and a wiring that optimally combines the two connections can be obtained according to the characteristics required of the LED display device after mounting.

  Conductive plate portion of the metal wiring portion 13 of the LED element substrate 1 of the present invention so that the arrangement of the insulating slit portion 132 satisfies the “specific arrangement conditions of the insulating slit portion” described in detail below. By making the shape and arrangement of 131 into a specific shape and arrangement, it is possible to further reduce the risk of bending damage of the LED element and the metal wiring portion of the LED element 2.

  The above “specific arrangement condition of the insulating slit portion” is that “one insulating slit portion is not on the same straight line as another adjacent insulating slit portion”. “Adjacent insulating slit portion” means that the other insulating plate portion adjacent to the one conductive plate portion constituting the outer edge of the one insulating slit portion constitutes the outer edge thereof. This refers to an insulating slit other than the slit. In other words, as long as the above-mentioned “specific arrangement conditions for insulating slit portions” are satisfied, in the flexible wiring board type LED element substrate, there are a plurality of insulating slit portions that are likely to be the starting point of bending damage of the LED elements and metal wiring portions. No longer communicates in a straight line across the basic units. Therefore, this makes it possible to reduce the risk of bending damage of the LED element or the metal wiring portion of the LED element substrate 1.

  Although various specific examples can be implemented as embodiments of the metal wiring part for realizing the above-mentioned “arrangement of the specific insulating slit part”, the shape of the metal wiring part in the three representative embodiments will be described below. Specific examples of the arrangement will be described with reference to FIGS. 7 and 8, respectively. In any of the following embodiments, the width of the insulating slit portion 132 is preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.15 mm or more and 0.5 mm or less. In addition, when the width of the insulating slit portion 132 is 0.5 mm or less, preferable heat transfer between the conductive plate portions 131 is possible. For example, when local heat generation occurs in a large-sized LED backlight of a local dimming method, the preferable heat transfer is maintained at a relatively low temperature from the conductive plate portion 131 at a relatively high temperature. The effect | action which moves the heat | fever to a certain conductive plate part 131 is mentioned. Thereby, the local high temperature in a large-sized LED backlight is dissipated to the whole board | substrate for LED elements, and the function fall and failure of each LED element by a local temperature rise can be prevented.

(First embodiment)
The shape and arrangement of the metal wiring part 13 in the first embodiment of the LED element substrate 1 are as shown in FIG. As shown in FIG. 7, the insulating slit portions 132 </ b> A to 132 </ b> D formed between the concave polygonal conductive plate portions 131 </ b> A all satisfy the condition of “arrangement of specific insulating slit portions”. Specifically, none of the insulating slits 132A to 132D are arranged on the same straight line. As a result, one insulating slit portion, which is likely to be a starting point for bending damage of LED elements and metal wiring portions, is linearly formed across the other insulating slit portions composed of the adjacent conductive plate portions 131 and a plurality of mounting basic units. It is possible to reduce the risk of bending damage of the LED element and the metal wiring part of the LED element substrate 1 without being communicated.

(Second Embodiment)
The shape and arrangement of the metal wiring portion 13 in the second embodiment of the LED element substrate 1 of the present invention are as shown in FIG. As shown in FIG. 8, the insulating slit portions 132A to 132F formed between the positive hexavalent conductive plate portions 131C satisfy the condition of “specific insulating slit portion arrangement” as in the first embodiment. ing. Insulating slits that tend to bend and damage LED elements and metal wiring parts do not communicate linearly across multiple mounting basic units, reducing the risk of bending damage to LED elements and metal wiring parts be able to. In the second embodiment, the bending strength of the LED element substrate 1 can be remarkably improved by forming a so-called honeycomb structure.

  The metal wiring portion 13 has the above embodiments as preferred specific examples, and in the LED element substrate 1, the range of at least 95%, preferably 98% or more of one surface of the resin substrate 11 is within this range. It is preferably covered with the metal wiring part 13. Thereby, preferable heat dissipation can be imparted to the LED display device using the LED element substrate 1.

  The metal thermal conductivity λ constituting the metal wiring part 13 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 part 13 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, both heat dissipation and electrical conductivity can be achieved. More specifically, since the heat dissipation from the LED element is stabilized and an increase in electrical resistance can be prevented, the variation in light emission between the LEDs is reduced, and the LED can stably emit light, and the LED life is also extended. . Further, since deterioration of peripheral members such as the substrate due to heat can be prevented, the product life of the image display device itself in which the LED element substrate is incorporated as a backlight can be extended.

  The surface resistance value of the metal wiring portion 13 is preferably 500Ω / □ or less, more preferably 300Ω / □ or less, further preferably 100Ω / □ or less, and particularly preferably 50Ω / □ or less. The lower limit is about 0.005Ω / □.

  Examples of the metal include metal foils such as aluminum, gold, silver, and copper. The thickness of the metal wiring part 13 should just be set suitably according to the magnitude | size of the electric current resistance requested | required of the board | substrate 1 for LED elements, etc., Although it does not specifically limit, 10 micrometers-50 micrometers in thickness are mentioned as an example. From the viewpoint of improving heat dissipation, the thickness of the metal wiring portion 13 is preferably 10 μm or more. Further, if the metal layer thickness is less than the above lower limit value, the influence of thermal shrinkage of the resin substrate 11 is large, and the warp after the processing is likely to increase during the solder reflow process. Is preferably 10 μm or more. On the other hand, when the thickness is 50 μm or less, sufficient flexibility of the LED element substrate can be maintained, and a decrease in handling property due to an increase in weight can be prevented.

[Solder layer]
In the LED element substrate 1, the metal wiring portion 13 and the LED element 2 are joined through the solder layer 14. Details of the soldering method will be described later, but can be roughly classified into either a reflow method or a laser method.

[Insulation protective film]
As described above, the insulating protective film 15 is mainly a substrate for an LED element except for a portion that requires electrical bonding on the surface of the metal wiring portion 13 and the resin substrate 11 with thermosetting ink. 1 to improve the migration resistance.

  As the thermosetting ink, a known ink can be suitably used as long as the thermosetting temperature is about 100 ° C. or less. Specifically, as a representative example of an ink that can preferably use an insulating ink having a polyester resin, an epoxy resin, an epoxy resin and a phenol resin, an epoxy acrylate resin, a silicone resin, or the like as a base resin, respectively. Can be mentioned. Of these, polyester-based thermosetting insulating ink is particularly preferable as a material for forming the insulating protective film 15 of the LED element substrate 1 because of its excellent flexibility.

  The thermosetting ink for forming the insulating protective film 15 may be a white ink further containing an inorganic white pigment such as titanium dioxide. By improving the whiteness of the insulating protective film 15, it is possible to improve the design.

  The formation of the insulating protective film 15 using the above insulating thermosetting ink can be performed by a known method such as screen printing.

[Reflective layer]
In the present embodiment, the reflective layer 16 is provided on the outermost surface on the light emitting surface side of the LED element substrate except for the mounting portion of the LED element 2 for the purpose of improving the light emitting capability in the LED mounting module 10 described above. Laminated. It is not particularly limited as long as it is a member having a reflective surface for reflecting the light emitted from the LED element and guiding it in a predetermined direction, but white polyester foam type white polyester, white polyethylene resin, silver vapor-deposited polyester, etc. And can be used as appropriate according to the required specifications.

<Method for producing LED element substrate>
The LED element substrate 1 can be manufactured by an etching process which is one of conventionally known methods for manufacturing an electronic substrate. Further, it is preferable to subject the resin in advance to a heat resistance improving process by annealing according to the material resin to be selected.

[Annealing treatment]
Although not essential in the present invention, conventionally known heat treatment means can be used for the annealing treatment. As an example of the annealing treatment temperature, when the thermoplastic resin forming the resin substrate 11 is PEN, the glass transition temperature to the melting point range, more specifically 160 ° C. to 260 ° C., more preferably 180 ° C. to 230 ° C. Range. An example of the annealing time is about 10 seconds to 5 minutes. According to such heat treatment conditions, the thermal contraction start temperature of PEN, which is generally about 80 ° C., can be improved to about 100 ° C.

[Etching process]
If necessary, a laminated body in which the metal wiring part 13 such as a copper foil used as the material of the metal wiring part 13 is laminated on the surface of the resin substrate 11 that has been subjected to the annealing process to obtain the material of the LED element substrate 1 is obtained. As a lamination method, a metal foil is adhered to the surface of the resin substrate 11 with an adhesive, or a plating method or a vapor deposition method (sputtering, ion plating, electron beam evaporation, Examples thereof include a method of depositing the metal wiring portion 13 by vacuum deposition, chemical vapor deposition, or the like. From the viewpoint of cost and productivity, a method of bonding a metal foil to the surface of the resin substrate 11 with a urethane-based adhesive is advantageous.

  Next, an etching mask patterned in the shape of the metal wiring portion 13 is formed on the surface of the metal foil of the laminate. In the future, the etching mask is provided so that the wiring pattern forming portion of the metal foil that will become the metal wiring portion 13 is free from corrosion by the etching solution. The method for forming the etching mask is not particularly limited. For example, the etching mask may be formed on the surface of the laminated sheet by exposing the photoresist or dry film through the photomask and then developing the ink mask. An etching mask may be formed on the surface of the laminated sheet by this printing technique.

  Next, the metal foil in a portion not covered with the etching mask is removed with an immersion liquid. Thereby, parts other than the location used as the metal wiring part 13 are removed among metal foil.

  Finally, the etching mask is removed using an alkaline stripping solution. As a result, the etching mask is removed from the surface of the metal wiring portion 13.

[Insulating protective film and reflective layer forming step]
After forming the metal wiring portion, an insulating protective film 15 and a reflective layer 16 are further laminated as necessary. These laminations 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.

<LED mounting module>
The LED mounting module 10 can be obtained by mounting an LED element on a flexible wiring board typified by the LED element substrate 1 described above. As described above, the wiring board used in the LED mounting module 10 of the present invention is not limited to the LED element substrate 1 described above. As long as the LED element is arranged on the flexible wiring board in a manner satisfying the arrangement conditions unique to the present invention, which will be described in detail below, the LED mounting module of the present invention is within the equivalent range.

(Conditions for LED elements)
The arrangement conditions of the LED elements in the LED mounting module 10 will be described with reference to FIGS.

The LED element placement condition in the LED mounting module 10 is to satisfy the following conditions (a) and (b). Here, (a) an arbitrary one LED element is a central LED element, and among the other LED elements arranged around the central LED element, the LED element having the smallest distance from the central LED element is the fourth in order. When selecting an element close to, the four other LED elements selected in this way are referred to as adjacent LED element groups.
(B) Assuming a two-dimensional XY coordinate in which the center of gravity of one LED element on the flexible wiring board is the origin and the longitudinal direction or the long axis direction of the resin substrate is the X axis direction, any of the LED elements belonging to the adjacent LED element group The other LED elements are also arranged such that the center of gravity is shifted from the X axis and Y axis of the two-dimensional XY coordinates.
The distance between the LED elements in the above refers to the distance between the centers of gravity of the upper surfaces of the LED elements. In addition, the LED element disposed on the outermost periphery of the metal wiring portion 13 is not assumed to be the above-described central LED element.

  FIG. 4 is an example of an arrangement that satisfies the above arrangement conditions (a) and (b). In FIG. 5, the adjacent LED element groups 21a, 21b, 21c, and 21d of the central LED element 20 have their centroids (positions represented by black dots in the figure) as X in the XY coordinates with the centroid of the central LED element as the origin. It is arranged so as to be largely displaced from the axis and the Y axis. With such an arrangement, it is possible to prevent the substrate from being bent unnecessarily due to the flexibility of the flexible substrate. Thereby, the risk of the occurrence of chain damage of the LED elements can be reduced. When the resin substrate is on a general rectangle, the longitudinal direction is the X-axis direction. For example, when the resin substrate is elliptical, the major axis direction is the X-axis.

  FIG. 5 is also an example of an arrangement that satisfies the above arrangement conditions (a) and (b). FIG. 6 shows only a part of the LED elements around an arbitrary central LED element, and shows an arrangement mode of the optional central LED element and its adjacent LED elements by a schematic diagram in which the display of the other LED elements is omitted. Is. In this arrangement, the center of gravity of the LED groups 21a, 21b, 21c, and 21d adjacent to the center LED element 20 (the position represented by a black dot in the figure) is the X axis in the XY coordinates described above with the center of gravity of the center LED element as the origin. Although it is a little from the Y-axis, it is arranged at a shifted position. Even with such an arrangement, it is possible to reduce the risk of chain damage of the LED elements due to the flexibility of the flexible substrate.

  On the other hand, FIG. 6 is an example of an arrangement that does not satisfy the arrangement conditions (a) and (b). In FIG. 7, the adjacent LED element groups 21a, 21b, 21c, and 21d of the central LED element 20 have their centroids (positions represented by black dots in the figure) as X in the XY coordinates with the centroid of the central LED element as the origin. It arrange | positions in the aspect located on an axis | shaft and a Y-axis. When such an arrangement prevents the board from being bent unnecessarily due to the flexibility of the flexible board, the risk of chain damage of the LED elements is caused by the arrangement specific to the present invention. Obviously bigger than.

  The LED element 2 mounted on the LED mounting module 10 may be a light emitting element using light emission at a PN junction where a P-type semiconductor and an N-type semiconductor are joined. There have been proposed a structure in which a P-type electrode and an N-type electrode are provided on the upper and lower surfaces of the element and a structure in which both the P-type and N-type electrodes are provided on one element surface. Any structure of the LED element 2 can be used for the LED mounting module 10 of the present invention, and among the above, the LED element having a structure in which both the P-type and N-type electrodes are provided on the element single side is particularly preferably used. Can do.

  The LED element 2 is a light emitting element that utilizes light emission at a PN junction where a P-type semiconductor and an N-type semiconductor are joined. There have been proposed a structure in which a P-type electrode and an N-type electrode are provided on the upper and lower surfaces of the element and a structure in which both the P-type and N-type electrodes are provided on one element surface. Any structure of the LED element 2 can be used for the LED mounting module 10 of the present invention, and among the above, the LED element having a structure in which both the P-type and N-type electrodes are provided on the element single side is particularly preferably used. Can do.

  The LED mounting module 10 of the present invention can mount 100 or more LED elements 2 as shown in FIG. It can be preferably used also for a large LED display device having a size of about 32 inches or more in terms of the screen size of the LED display device. In addition, in the manufacture of large display devices of approximately 32 inches or more, a large flexible wiring board type made of a single resin is used in contrast to the conventional combination of a plurality of small-sized substrates. Since the LED element substrate 1 has a high degree of freedom in circuit design, the arrangement interval and the like of the LED elements 2 to be mounted can be freely adjusted. Can be handled at low cost.

<Method for manufacturing LED mounting module>
The manufacturing method of the LED mounting module 10 using the board | substrate 1 for LED elements is demonstrated. The joining of the LED element 2 to the metal wiring part 13 can be preferably performed by soldering. This solder bonding can be performed by a reflow method or a laser method. In the reflow method, the LED element 2 is mounted on the metal wiring part 13 through solder, and then the LED element substrate 1 is transported into the reflow furnace, and hot air at a predetermined temperature is applied to the metal wiring part 13 in the reflow furnace. In this method, the solder paste is melted by spraying, and the LED element 2 is soldered to the metal wiring portion 13. The laser method is a method of soldering the LED element 2 to the metal wiring portion 13 by locally heating the solder with a laser.

  When performing the solder bonding of the LED element 2 to the metal wiring part 13, it is preferable to adopt a method of performing solder reflow by laser irradiation from the back side of the resin substrate 11. Thereby, the ignition of the organic component of the solder by heating and the accompanying damage to the base material can be more reliably suppressed.

<LED display device>
FIG. 9 is a perspective view schematically showing an outline of a layer configuration of the LED display device 100 using the LED mounting module 10. The LED display device 100 displays information (images) such as characters and videos on the monitor 3 by driving (emitting light) the plurality of LED elements 2 arranged in a substantially matrix at predetermined intervals. The LED element 2 is mounted on the metal wiring portion 13 of the LED element substrate 1. Moreover, it is more preferable that the heat dissipation structure 4 for radiating the heat radiated from the LED mounting module 10 to the outside more efficiently is installed on the back side of the resin base material. By using the LED mounting module 10 of the present invention, for example, a large LED display device having a screen size (diagonal length) of 32 inches or more is manufactured at a lower cost and with improved quality stability. be able to.

  The LED mounting module of the present invention described above and the LED display device using the same have the following effects.

  (1) In the LED mounting module 10 using the flexible wiring board that has been intended to reduce the bending damage of the LED element and the metal wiring part, the arrangement of the LED element 2 satisfies the arrangement condition unique to the present invention. Thereby, the risk of the bending damage of the LED element and metal wiring part mainly resulting from the flexibility of base resin in the LED mounting module using a flexible wiring board can be reduced.

  (2) The LED mounting module 10 is made of a single flexible resin having a diagonal length of 32 inches or more. Thus, since a large LED display device that has been formed only by joining a plurality of LED mounting modules can be configured by a single LED element substrate 1, the productivity and quality stability of the LED display device can be reduced. It can be remarkably improved. In addition, since such a large substrate generally has a high risk of the above-described bending damage, it is possible to receive more of the benefits of productivity improvement by the effects of the present invention.

  (3) It was set as the LED display device formed by laminating | stacking the LED mounting module as described in (1) or (2), and the display screen. Thereby, even if it is a large-sized LED display device with a screen size of 32 inches or more, for example, what has excellent quality stability can be provided with high productivity.

  As mentioned above, according to this invention, it is an LED mounting module using a flexible wiring board, Comprising: The LED mounting module by which the risk of the bending damage of the LED element and metal wiring part mainly resulting from the flexibility of base-material resin was reduced Can be provided.

DESCRIPTION OF SYMBOLS 1 Substrate for LED elements 11 Resin substrate 12 Adhesive layer 13 Metal wiring part 131 Conductive plate part 132 Insulating slit part 133 Connector wiring 134 Terminal 14 Solder layer 15 Insulating protective film 16 Reflective layer 2 LED element 20 Central LED element 21a, 21b , 21c, 21d Adjacent LED element group 3 Monitor 4 Heat dissipation structure 10 LED mounting module 100 LED display device

Claims (3)

An LED mounting module in which LED elements are mounted in a matrix on a flexible wiring board formed by forming a metal wiring portion on a resin substrate made of a flexible resin,
The LED element is disposed at a position satisfying the following conditions (a) and (b).
(A) Arbitrary one LED element is set as a central LED element, and among the other LED elements arranged around the central LED element, the one closest to the central LED element is the fourth closest in order. When selecting up to one, four other LED elements selected in this way are referred to as adjacent LED element groups.
(B) Assuming a two-dimensional XY coordinate in which the center of gravity of one LED element on the flexible wiring board is the origin and the longitudinal direction or the long axis direction of the resin substrate is the X axis direction, any of the LED elements belonging to the adjacent LED element group The other LED elements are also arranged such that the center of gravity is shifted from the X axis and Y axis of the two-dimensional XY coordinates. The resin substrate is made of a single flexible resin having a diagonal length of at least 32 inches or more,
The LED mounting module according to claim 1, wherein 100 or more LED elements are mounted in a substantially matrix form.   The LED display apparatus which uses the LED mounting module of Claim 1 or 2 as a backlight light source.

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