TWI688082B - Substrate for LED element and LED display device - Google Patents

Abstract

The problem of the present invention is to reduce the use of flexible substrate type LED elements There is a risk of bending damage in the substrate, which is caused by the difference in the flexibility of the resin substrate and the bending elastic coefficient of the resin substrate and the metal wiring portion.

The present invention provides a substrate 1 for an LED element, comprising: a resin substrate 11 composed of a flexible resin film; and a metal wiring portion 13 formed on the resin substrate 11 to be able to conduct the LED element 2, The LED elements 2 are arranged in a matrix; and the metal wiring portion 13 is composed of a plurality of circular or polygonal conductive plate portions 131 arranged on the resin substrate 11, and two adjacent conductive plate portions 131 The non-conducting part in between is also an insulating slit 132, which is not on the same straight line as another adjacent insulating slit 132.

Description

LED element substrate and LED display device

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

In recent years, LED display devices such as liquid crystal televisions and liquid crystal displays that use LED elements as backlights to replace the conventional cathode ray tube type screens and meet the requirements of low power consumption, large-scale equipment, and thinning have been used The popularity of is rapidly progressing.

In order to construct LED elements as light sources in these display devices, substrates for various LED elements composed of a support substrate and a circuit portion are generally used. Furthermore, a laminate formed by mounting LED elements on these substrates (in this specification, such a laminate component will be referred to as an "LED package module" hereinafter) can also be used as a light source for various display devices such as the above-mentioned LCD TVs LED backlight is widely used.

In these display devices, in order to improve the image quality, the brightness of the light source is required to be improved. However, the increase in the amount of heat generated from the LED element accompanying the increase in brightness also causes an increase in power consumption and a decrease in the luminous ability of the LED element. Therefore, as far as the LED building module is concerned, along with the improvement of brightness, it is also strongly required to improve the heat dissipation. This requirement to improve heat dissipation has become a particularly urgent problem in displays such as liquid crystal televisions with the recent advancement in size.

As a configuration type of an LED element for improving heat dissipation, for example, a method of directly mounting an LED element on a metal surface of a metal base substrate has been proposed (see Patent Document 1). However, this method lacks design freedom because the metal substrate is plate-shaped, and because it will be produced in batches of one substrate at a time, productivity is also low.

In this regard, there is also proposed a circuit board, which is a substrate formed by forming a metal circuit on a flexible resin substrate (hereinafter referred to as a "flexible substrate"), and additionally provided only for showing heat dissipation A functional metal layer that is provided separately from the conduction circuit (Patent Document 2), or a portion formed separately from the circuit for conduction is also a thermal connection portion (Patent Document 3).

However, in any of these flexible substrates until it is assembled into the final product of the LED display device, etc., there are occasional cases where fatal damage to the LED display device, etc., is caused. Due to the flexibility of the resin substrate and the difference in the bending elastic coefficient of the resin substrate and the metal circuit portion, the substrate bending and the LED element that cannot be restored Damage to the structure, etc. Moreover, this has become one of the important reasons hindering the improvement of the productivity of LED display devices.

[Prior Technical Literature] (Patent Literature)

Patent Literature 1: Japanese Patent Laid-Open No. 2009-81194

Patent Document 2: Japanese Patent Laid-Open No. 2012-59867

Patent Document 3: Japanese Special Publication No. 2013-522893

The present invention has been completed in view of the above circumstances, and its object is to reduce the risk of bending damage in a flexible substrate type LED element substrate, which is caused by the flexibility of the resin substrate and the resin substrate This is caused by the difference in the bending elastic coefficient of the metal line part.

As a result of repeated careful research, the present inventors found that the arrangement of the insulating slits between the metal wiring portions of the flexible substrate type LED element substrate formed by forming the metal wiring portions on the flexible resin film By forming the metal circuit portion in a unique and specific configuration of the present application, the above problems can be solved, and the present invention has been completed. Specifically, the present invention provides the following inventions.

(1) A substrate for an LED element, comprising: a resin substrate composed of a flexible resin film; and a metal wiring portion formed on the resin substrate so as to be able to conduct LED elements, and these LEDs The elements are arranged in a matrix; and the metal line portion is composed of a plurality of circular or polygonal conductive plate portions arranged on the resin substrate, and non-conduction between two adjacent conductive plate portions The part is also an insulating slit portion, which is not on the same straight line as another adjacent insulating slit portion.

(2) The substrate for an LED element according to (1), wherein the conductive plate portion is a regular hexagonal conductive plate portion.

(3) The substrate for an LED element according to (1), wherein the metal line portion is composed of a plurality of perfect circular or elliptical conductive plate portions arranged alternately on the resin substrate.

(4) The substrate for an LED element according to any one of (1) to (3), wherein the metal wiring portion covers a range of 70% or more of one surface of the resin substrate.

(5) The substrate for an LED element according to (1) or (2), wherein the metal wiring portion covers a range of 95% or more of one surface of the resin substrate.

(6) The substrate for an LED element according to any one of (1) to (3), wherein the resin substrate has a diagonal length of 32 inches or more and is composed of a single flexible resin film Posed.

(7) An LED display device formed by stacking an LED building module and a display screen, the LED building module being the substrate for LED elements according to any one of (1) to (3) It is made of LED components.

According to the present invention, it is possible to provide a substrate for LED elements, which is a flexible substrate type LED element substrate, and the risk of bending damage is reduced, and the bending damage is caused by the flexibility of the resin substrate And the difference in bending elastic coefficient between the resin substrate and the metal wiring part.

1. 1A‧‧‧Substrate for LED components

2‧‧‧LED components

3‧‧‧ screen

4‧‧‧ heat dissipation structure

10‧‧‧LED building module

11‧‧‧Resin substrate

12‧‧‧adhesive layer

13‧‧‧Metal Line Department

131, 131A, 131B, 131C, 131D, 131E, 131F, 131G, 131H, 131I, 131J

132, 132A, 132B, 132C, 132D, 132E, 132F, 132DF, 132DI, 132EJ, 132GH‧‧‧Insulation slit

133‧‧‧Connector circuit

134‧‧‧terminal

14‧‧‧ solder layer

15‧‧‧Insulating protective film

16‧‧‧Reflective layer

100‧‧‧LED display device

X, Y‧‧‧ direction

d‧‧‧Diagonal

FIG. 1 is a plan view schematically showing the overall configuration of the metal wiring portion of the LED element substrate of the present invention.

FIG. 2 is a plan view schematically showing the overall configuration of a metal wiring portion of another embodiment of the LED element substrate of the present invention.

Fig. 3 is a partial cross-sectional view of an LED package module in which LED elements are mounted on a substrate for LED elements of the present invention.

Fig. 4 is a plan view schematically showing an LED building module in which LED elements are mounted on the LED element substrate of the present invention.

Fig. 5 is a plan view showing the shapes of the conductive plate portion and the insulating slit portion in the metal wiring portion and the positional relationship among these in the first embodiment of the substrate for an LED element of the present invention.

Fig. 6 is a plan view showing the shapes of the conductive plate portion and the insulating slit portion in the metal wiring portion and the positional relationship among these in the second embodiment of the substrate for an LED element of the present invention.

FIG. 7 is a plan view showing the shape of the conductive plate portion and the insulating slit portion in the metal wiring portion and the positional relationship among these in the third embodiment of the substrate for an LED element of the present invention.

FIG. 8 is a plan view showing the shapes of the conductive plate portion and the insulating slit portion in the metal wiring portion and the positional relationship of the fourth embodiment of the substrate for LED element of the present invention.

Fig. 9 is a perspective view schematically showing the outline of the layer configuration of an LED display device using the LED package module of the present invention.

Hereinafter, each embodiment of the LED element substrate, LED package module, and LED display device of the present invention will be described. The present invention is not limited to any of the following embodiments, and can be implemented with appropriate changes within the scope of the object of the present invention.

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

<LED element substrate>

As shown in FIGS. 1 to 3, the substrate 1 for LED elements has a metal foil formed on the surface of a resin substrate 11 made of a flexible resin film with an adhesive layer 12 interposed therebetween The conductive metal line portion 13. The metal line portion 13 is formed on the resin substrate 11 so as to be able to conduct the LED elements 2, and the LED elements 2 are arranged in a matrix. The details of the shape and arrangement of the metal line portion 13 which is a characteristic part of the present invention will be described later.

In addition, as shown in FIG. 3, the substrate 1 for LED elements 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 characteristics of the substrate 1 for LED elements, this insulating protective film 15 is formed in such a manner as to cover the entire surface of the surface of the metal wiring portion 13 except for the connection portion for constructing the LED element 2, and Approximately the entire surface of the portion of the surface of the resin substrate 11 where the metal line portion 13 is not formed.

Moreover, as shown in FIG. 3, the substrate 1 for LED elements preferably has a reflective layer 16 made of white resin or the like further laminated on the insulating protective film 15 on the resin substrate 11 and the metal circuit portion 13 . In particular, in the case of using an LED mounting module 10 formed by mounting LED elements 2 on an LED element substrate 1 as a backlight of the LED display device 100 shown in FIG. 9, it is generally necessary The reflective layer 16 is arranged on the outermost surface of the LED building module. However, by providing the insulating protective film 15 with a reflection function, the required protective function can be ensured by the insulating protective film without providing a reflective layer.

As shown in FIG. 3, the substrate 1 for LED elements will become an LED package module 10, and the LED package module 10 is an LED element 2 structured to a metal circuit via a solder layer 14 in a conductive state Part 13 is made. Moreover, this LED mounting module 10 can be preferably used as a backlight of an LED display device such as an LED liquid crystal television.

The size of the substrate 1 for LED elements is not particularly limited. For example, the LED element substrate 1 of the present invention can also be preferably used in the large-sized LED packaging module shown in FIG. 4. The group has a diagonal d of 32 inches or more and 100 or more LED elements 2 are arranged in a matrix. FIG. 4 is an example of the configuration of the LED element 2 on the LED element substrate 1, and illustrates an example in which 40 LED elements 2 in total are installed in the X direction and 30 in the Y direction. In addition, the planar shape of the substrate for LED elements of the present invention is not necessarily limited to a rectangular shape. In this specification, "diagonal length is 32 inches or more" means, for example, the length of the major axis when the LED element substrate is oval.

〔Resin substrate〕

As a material of the resin substrate 11, a resin film formed by molding a thermoplastic resin into a sheet shape and having flexibility can be used. Here, the term “flaky” means a concept including a thin film, and as long as it is flexible, there is no difference between the two in the present invention.

The thermoplastic resin used as the material of the resin substrate 11 is required to have high heat resistance and insulation. As such a resin, polyimide resin (PI) can be used, and its heat resistance is excellent in dimensional stability, mechanical strength, and durability when heated. In addition, various other thermoplastic resins whose heat resistance and dimensional stability are improved by performing heat treatment such as annealing treatment can also be used. For example, polyethylene naphthalate (PEN), etc., which is provided with sufficient heat resistance and dimensional stability by annealing treatment. In addition, PET (polyethylene terephthalate), etc., whose flame retardancy is improved by the addition of flame-retardant inorganic fillers, etc., can also be selected as the raw material resin of the resin substrate.

The thermoplastic resin forming the resin substrate 11 is preferably one that improves heat resistance in the following manner: by the above annealing treatment, its heat shrinkage The initial temperature becomes equal to or higher than the thermosetting temperature of the thermosetting ink used to form the insulating protective film 15. For example, in the case where the insulating protective film 15 is formed using a thermosetting ink with a thermosetting temperature of about 80°C, as long as the initial heat shrinkage temperature of PEN, which is usually about 80°C, is increased by annealing treatment It can be up to about 100℃. With this, it is possible to form an insulating protective film 15 having sufficient heat resistance, strength, and insulation while avoiding minute thermal damage to the resin substrate 11.

In addition, in this specification, the "heat shrinkage starting temperature" means that a sample sheet composed of a thermoplastic resin, which is a measurement object, is mounted on a TMA (thermomechanical analyzer) device, a load of 1 g is applied, and the heating rate is 2 ℃/min up to 120 ℃, measure the shrinkage (expressed in %) at that time, then output this data and record the graph of temperature and shrinkage, and read the deviation from the 0% baseline caused by shrinkage Temperature, and this temperature as the initial temperature of heat shrinkage. In addition, the "thermosetting temperature" in this specification means measuring and calculating the temperature at the position where the thermosetting reaction just started when the thermosetting resin to be measured is heated, and this temperature is regarded as the thermosetting temperature.

For the insulation of the resin substrate 11, for example, a resin is required which has a volume specific resistivity which is used as an LED display when the LED element substrate 1 is used as a backlight of an LED display device When the device is integrated, the required insulating property can be imparted to the substrate 1 for LED elements. Generally speaking, the volume inherent resistivity of the resin substrate 11 is preferably 10 ¹⁴ Ω. cm or more, further preferably 10 ¹⁸ Ω. cm above.

The thickness of the resin substrate 11 is not particularly limited, but it is preferably about 10 μm or more and 100 μm or less from the viewpoint of the balance between heat resistance and insulation and manufacturing cost. In addition, from the viewpoint of maintaining good productivity in roll-to-roll manufacturing, it is preferably within the above-mentioned thickness range.

The size of the resin substrate 11 is not particularly limited. However, the substrate for LED elements can be, for example, a diagonal line having a length of 32 inches or more and composed of a single resin film. In this specification, "single resin film" means that the resin film is not an aggregate of a plurality of resin films or a bonded body formed by such physical bonding, but a resin film composed of a single sheet-shaped film. Such a single large-sized film can be manufactured by a special extrusion molding device that can manufacture films outside the range of conventional specifications.

〔Adhesive layer〕

The metal circuit portion 13 is preferably bonded to the surface of the substrate 1 for LED elements by a dry lamination method via an adhesive layer 12. As long as the adhesive forming the adhesive layer 12 has heat resistance at the thermosetting temperature of the thermosetting ink forming the insulating protective film 15, a known resin-based adhesive can be suitably used. Among these resin adhesives, urethane-based, polycarbonate-based, or epoxy-based adhesives can be particularly preferably used.

[Metal Line Department]

The substrate for an LED element of the present invention is mainly characterized by reducing the shape and arrangement of the metal circuit portion to a unique aspect, and reducing The risk of bending damage. Hereinafter, the details of the shape and arrangement of this metal line portion will be described.

The metal wiring portion 13 is a wiring pattern composed of a polygonal or circular conductive plate portion 131 on the surface of the substrate 1 for LED elements. The conductive plate portion 131 is formed of a conductive base material. The shape of the conductive plate portion 131 in a plan view may be a polygonal shape or a circular shape capable of conducting between the LED elements 2 arranged in a matrix.

When the plan view shape of the conductive plate portion 131 is a polygonal shape, the shape may be a convex polygonal shape such as a regular polygonal shape, or a concave polygonal shape as shown in FIG. 5.

When the shape of the conductive plate portion 131 in a plan view is a circular shape, the shape may be a perfect circular shape as shown in FIG. 8 or an elliptical shape. In addition, as long as it has such a circular shape, ellipses with different ratios and sizes of major and minor diameters, or perfect circles with different sizes may coexist.

The arrangement of the metal line portion 13 is preferably: the junction part of the LED element 2 to the metal line portion 13 that is the basic unit of construction, as shown in FIGS. 1 and 2, etc., to enable the LED element 2 to be turned on The pattern is repeated in the XY two directions in the matrix. The basic unit of construction means that, as shown in FIG. 3, the gap portion between the adjacent set of conductive plate portions 131 and the insulating slit portion 132 in the substrate 1 for the LED element is composed of a portion.

The insulating slit portion 132 means, in detail, the unformed portion of the metal wiring portion 13 (that is, the portion where the metal wiring portion is not formed) in the LED element substrate 1 and is the above-mentioned adjacent set of conductive Board Department Non-conductive part between 131. When the shape of the conductive plate portion 131 in a plan view is a polygonal shape, the insulating slit portions 132A to 132D in FIGS. 5 and 6 correspond to the insulating slit portion. In addition, when the shape of the conductive plate portion 131 in a plan view is a circular shape, the insulating slit portions 132DF, 132GH, 132DI, 132EJ, etc. in FIG. 8 correspond to the insulating slit portions.

Furthermore, as shown in FIG. 1, the metal line portion 13 includes the following structure in addition to the above-mentioned basic unit of the structure: the connector line 133, which is arranged in a matrix-like arrangement The conductive plate portions 131 in different rows or columns are connected; and, the terminal 134 is used to electrically connect the LED mounting module 10 and an external power supply at the end of the row or column. In the substrate 1 for LED elements, the layout of the conductive plate portions 131, the connector lines 133, and the terminals 134 constituting the metal wiring portion 13 and the combination of these have a high degree of freedom in design. With regard to the conduction form of most LED elements 2, Either series or parallel connection can be used, and depending on the characteristics required by the assembled LED display device, the two connection methods can be made into the most suitable combination of circuits.

The metal line portion 13 of the LED element substrate 1 of the present invention is to reduce the risk of the above-mentioned bending damage, and the arrangement of the insulating slit portion 132 satisfies the “disposition conditions of the insulating slit portion unique to the present invention” described in detail below ", the shape and arrangement of the conductive plate portion 131 are limited to a specific shape and arrangement.

"The arrangement condition of the insulating slit portion unique to the present invention" is "one insulating slit portion and the other adjacent insulating slit portion are not on the same straight line". "Adjacent insulation slit part" means another insulation slit part, the other An insulating slit portion whose outer edge is formed by a conductive plate portion constituting an outer edge of an insulating slit portion and an adjacent another conductive plate portion, and the other insulating slit portion is other than the aforementioned one insulating slit portion . That is, as long as the above-mentioned "arrangement conditions of the insulating slit portions unique to the present invention" are satisfied, in the flexible substrate-type LED element substrate, the insulating slit portions that are likely to be the origin of bending damage will not cross a plurality of structures Install the basic unit without connecting to a straight line. Therefore, by this, the substrate 1 for LED elements can be made into a person whose risk of bending damage is reduced.

Furthermore, as shown in FIG. 8, when the shape of the conductive plate portion 131 in a plan view is a circular shape, the circular conductive plate portion 131 can be provided by “arranged in a staggered shape” on the resin substrate 11 It is a configuration that "one insulating slit is not on the same straight line as another adjacent insulating slit". Here, the arrangement in a staggered manner means that the arrangement is other than a completely lattice-like arrangement, and it is preferable to arrange in the center of the conductive plate portions in adjacent rows within the matrix formed by the metal line portions 13 The coordinate positions are different in the mutual rows, and are arranged in a zigzag pattern with a fixed amplitude in the column direction. As a result, in the matrix of the metal line portions 13, there will be no insulation slits formed across the rows or columns and formed “in the same straight line”, that is, “continuously” in the “same direction”. Therefore, as shown in FIG. 2, in the LED element substrate 1A in which the shape of the conductive plate portion 131 is circular in plan view, the risk of bending damage can be reduced in the same manner as the LED element substrate 1 in FIG. 1. Moreover, when the shape of the conductive plate portion 131 in a plan view is a circular shape, "the direction of the insulating slit portion 132 (for example, the insulating slit portion 132EJ)" means; a pair of adjacent conductive plates forming the insulating slit portion The tangent direction of the point on each outer circumference of the portion 131 (for example, the conductive plate portion 131E and the conductive plate portion 131J) at which the distance between the two points becomes the smallest is approximately the same direction as the tangent direction. As a specific example, in FIG. 8, the direction of the insulating slit 132EJ is the Y direction in the figure.

As an implementation form of the metal line portion for realizing the above-mentioned “specific arrangement conditions of the present invention”, various specific examples can be implemented, and specific examples of the shape and arrangement of the metal line portion will be described with reference to FIG. 8. However, the substrate for the LED element of the present invention is not limited to the following embodiments as long as the conductive plate portion satisfies the condition of "specific arrangement of the present invention", and can have various applications within the scope of satisfying the above conditions. The invention includes all of these.

As an implementation type of the metal line portion for realizing the above-mentioned "arrangement of the insulating slit portion unique to the present invention", various specific examples can be implemented. The following is a description of the shape and the shape of the metal line portion in the four representative embodiments. Specific examples of the arrangement will be explained while referring to the figures from FIG. 5 to FIG. 8 respectively. However, the substrate for an LED element of the present invention is not limited to the following four embodiments as long as it satisfies the above-mentioned "arrangement of insulating slit portions unique to the present invention", and may be within the range satisfying the above conditions There are various application types, and the present invention includes all of these application types.

(First embodiment)

In the first embodiment of the LED element substrate 1 of the present invention, the shape and arrangement of the metal wiring portion 13 are as shown in FIG. 5. As shown in FIG. 5, an insulating slit formed between the conductive plates 131A of a concave polygon shape Any one of the sections 132A to 132D satisfies the condition of "arrangement of insulating slits unique to the present invention". Specifically, none of the insulating slit portions 132A to 132D are arranged in the same straight line with each other. As a result, an insulating slit portion that easily becomes the starting point of bending damage, and another insulating slit portion formed by the adjacent conductive plate portion 131, become a basic unit that does not span a plurality of structures and does not communicate in a straight line. The risk of bending damage to the substrate 1 for LED elements can be reduced.

(Second embodiment type)

In the second embodiment of the LED element substrate 1 of the present invention, the shape and arrangement of the metal wiring portion 13 are as shown in FIG. 6. As shown in FIG. 6, the insulating slit portions 132A to 132D formed between the conductive plates 131B of the concave polygonal shape, as in the first embodiment, any one of them satisfies the Conditions of "configuration". Since the insulating slit portion that is likely to be the starting point of bending damage does not span the basic unit of the plural structure and does not communicate in a straight line, the risk of bending damage can be reduced. In addition, by adjusting the arrangement angle of the conductive plate portion as in the second embodiment, the LED element 2 can be arranged in a complete lattice shape as needed while satisfying the condition of “arrangement of the insulating slit portion unique to the present invention”.

(Third embodiment)

In the third embodiment of the LED element substrate 1 of the present invention, the shape and arrangement of the metal wiring portion 13 are as shown in FIG. 7. As shown in FIG. 7, the insulating slits 132A to 132F formed between the conductive plates 131C in a regular hexagonal shape, as in the first and second embodiments, satisfy either of the "insulating slits unique to the present invention" Condition of the Because of capacity The insulating slit portion, which is likely to be the starting point of bending damage, does not cross the basic unit of the plural structure and does not communicate in a straight line, so the risk of bending damage can be reduced. In addition, in the third embodiment, by forming a so-called honeycomb structure, the bending strength of the LED element substrate 1 can be significantly improved.

In addition, in the above-mentioned first to third 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, better heat transfer between the conductive plate portions 131 becomes possible. For better heat transfer, for example, in a large LED backlight of a local dimming method, when local heat generation occurs, the heat is transferred from the conductive plate portion 131, which has become a relatively high temperature portion, to a relatively low temperature. The movement of the conductive plate portion 131. As a result, it is possible to dissipate the local high temperature in the large-sized LED backlight to the entire LED element substrate, and to prevent the function of each LED element from being degraded or malfunctioning due to the local temperature rise.

(Fourth embodiment)

In the fourth embodiment of the LED element substrate 1 of the present invention, the conductive plate portion 131 has a circular shape in plan view, and the shape and arrangement of the metal wiring portion 13 are as shown in FIG. 8. In this fourth embodiment, the insulating slit portion 132EJ formed between the circular conductive plate portions 131D and the conductive plate portions 131J arranged in a staggered shape, and the conductive plate portions adjacent by the conductive plate portions 131D The insulating slit portions 132DF and 132DI formed by the 131F or the conductive plate portion 131I are not arranged to be aligned with each other in the same straight line. As such, in the fourth embodiment, Similar to the first to third embodiments, the condition of "arrangement of insulating slits unique to the present invention" can be satisfied, and an insulating slit that easily becomes the starting point of bending damage and the adjacent one formed by the conductive plate 131 An insulating slit portion does not cross a plurality of basic units assembled and does not communicate in a straight line, so that the risk of bending damage of the LED element substrate 1 can be reduced.

Moreover, in this fourth embodiment, the minimum width of the insulating slit portion 132 (the shortest distance between the circumferences of the adjacent conductive plate portions 131) is preferably 0.1 mm or more and 1.0 mm or less, further preferably 0.15 mm above and below 0.5mm. In addition, when the width of the insulating slit portion 132 is 0.5 mm or less, better heat transfer between the conductive plate portions 131 becomes possible. For better heat transfer, for example, in a large-area LED dimming system with local dimming, when local heat generation occurs, the heat is transferred from the conductive plate portion 131 which has become a relatively high temperature portion to the conductive plate portion which is still relatively low temperature. 131 movement effect. As a result, it is possible to dissipate the local high temperature in the large-sized LED backlight to the entire LED element substrate, and to prevent the function of each LED element from being degraded or malfunctioning due to the local temperature rise.

FIG. 8 exemplifies the case where all the conductive plate portions 131 are perfectly round and of the same size, but it can be mixed arbitrarily by mixing ellipses of different sizes, or arbitrarily mixing ellipses with different ratios of long and short diameters, for example. Various circuit configurations are formed, and the coverage rate due to the metal line portion can be increased to further improve heat dissipation.

Furthermore, in any of the above-mentioned embodiments, the arrangement of the metal line portion 13 is not limited as long as it can configure the LED element. For specific configurations, etc. However, in the substrate 1 for LED elements, it is preferable that at least 70% and more preferably 75% or more of the side surface of the resin substrate 11 is covered by the metal wiring portion 13.

Particularly in the first to third embodiments, that is, in the case where the conductive plate portion 131 has a polygonal shape, it is preferable that at least 95% and preferably 98% or more of one side surface of the resin substrate 11 Is covered by the metal line portion 13. In this way, the LED display device formed by using the substrate 1 for LED elements can provide better heat dissipation.

In any of the above-mentioned embodiments, the thermal conductivity λ of the metal constituting the metal line portion 13 is preferably 200 W/(m·K) or more and 500 W/(m.K) or less, and more preferably 300 W/(m .K) above and 500W/(m.K) below. The resistivity R of the metal constituting the metal line portion 13 is preferably 3.00×10 ⁻⁸ Ωm or less, and more preferably 2.50×10 ⁻⁸ Ωm or less. Here, for the measurement of the thermal conductivity λ, for example, a thermal conductivity meter QTM-500 manufactured by Kyoto Electronics Co., Ltd. can be used, and for the measurement of the resistivity R, for example, a 6517B electrometer manufactured by Keithley can be used. Therefore, for example, in the case of copper, the thermal conductivity λ is 403 W/(m·K), and the resistivity R becomes 1.55×10 ⁻⁸ Ωm. This makes it possible to achieve both heat dissipation and electrical conductivity. More specifically, since the heat dissipation from the LED element is stable and prevents an increase in resistance, the variation in light emission between the LEDs becomes smaller, stable light emission of the LED becomes possible, and the LED life is also extended. Furthermore, since deterioration of peripheral components such as a substrate due to heat can also be prevented, the product life of the image display device itself assembled with the LED element substrate as a backlight can also be extended.

In addition, in any of the above-mentioned embodiments, the surface resistance value of the metal line portion 13 is preferably 500 Ω/□ or less, further preferably 300 Ω/□ or less, more preferably 100 Ω/□ or less, and particularly preferably 50 Ω/ □ Below. The lower limit is about 0.005Ω/□.

As the metal forming the metal line portion 13, metal foils such as aluminum, gold, silver, and copper can be exemplified. The thickness of the metal wiring portion 13 may be appropriately set depending on the magnitude of current resistance required by the LED element substrate 1 and the like, and is not particularly limited, but as an example, a thickness of 10 μm to 50 μm may be mentioned. From the viewpoint of improving heat dissipation, the thickness of the metal line portion 13 is preferably 10 μm or more. In addition, if the thickness of the metal layer is less than the above lower limit, the influence of the thermal shrinkage of the resin substrate 11 is large, and the warpage after the process is likely to increase during the solder reflow process, so from this point of view In other words, the thickness of the metal line portion 13 is preferably 10 μm or more. On the other hand, by having the thickness of 50 μm or less, sufficient flexibility of the substrate for LED elements can be maintained, and it is also possible to prevent a decrease in handleability due to an increase in weight.

〔Solder layer〕

In the LED element substrate 1, the bonding of the metal wiring portion 13 and the LED element 2 is performed via the solder layer 14. The details of this bonding method performed by solder are described later, but in general, it can be performed by either of the two methods of reflow method or laser method.

〔Insulation protective film〕

As described above, the insulating protective film 15 is formed on the surfaces of the metal circuit portion 13 and the resin substrate 11 by thermosetting ink except for electrical connection The composition is a part other than the necessary part, and it is mainly for improving the migration resistance of the substrate 1 for LED elements.

As the thermosetting ink, as long as the thermosetting temperature is approximately 100° C. or less, a known ink can be appropriately and preferably used. Specifically, the following can be cited as representative examples of inks that can be suitably used: polyester-based resins, epoxy-based resins, epoxy-based and phenolic-based resins, epoxy acrylate resins, and polysilicon Oxygen-based resins are used as insulating inks for the base resin. Among these, as the material for forming the insulating protective film 15 of the substrate 1 for LED elements, a polyester-based thermosetting insulating ink with excellent flexibility can be used particularly well.

In addition, the thermosetting ink forming the insulating protective film 15 may be, for example, a white ink, which further contains an inorganic white pigment such as titanium dioxide. By whitening the insulating protective film 15, the designability can be improved.

In addition, the above-mentioned formation of the insulating protective film 15 by the insulating thermosetting ink can be performed by a known method such as screen printing.

〔Reflective layer〕

The reflective layer 16 is for the purpose of improving the luminous ability in the above-mentioned LED package module 10, and in this embodiment type is a structure which is laminated on the outermost surface of the light-emitting surface side of the LED element substrate except for the LED element 2 Parts other than parts. As long as it has a reflective surface, the reflective surface is used to reflect the light emitted by the LED element and guide it to a predetermined direction, which is not particularly limited, but it can be appropriate depending on the use of the final product and its required specifications, etc. White polyester foamed white polyester, white polyethylene resin, silver vapor-deposited polyester, etc. are used.

<Manufacturing method of substrate for LED element>

The substrate 1 for LED elements can be manufactured by one of conventionally known electronic substrate manufacturing methods, that is, a manufacturing method including an etching step. In addition, depending on the selected raw material resin, it is preferable to subject the resin to heat resistance improvement treatment by annealing treatment in advance.

[Annealing]

Although not necessary in the present invention, the annealing treatment can use a conventionally well-known heat treatment means. As an example of the annealing temperature, in the case where the thermoplastic resin forming the resin substrate 11 is PEN, the range is from the glass transition temperature to the melting point, more specifically from 160°C to 260°C and further preferably from 180°C Up to 230°C. The annealing treatment time can be exemplified from about 10 seconds to about 5 minutes. According to such heat treatment conditions, the thermal shrinkage onset temperature of PEN, which is generally about 80°C, can be increased to about 100°C.

[Etching step]

If necessary, on the surface of the resin substrate 11 subjected to the annealing treatment, copper foil or the like as a raw material of the metal wiring portion 13 is laminated to obtain a laminate as a raw material of the substrate 1 for the LED element. Examples of the lamination method include a method of bonding a metal foil to the surface of the resin substrate 11 with an adhesive, or a method of directly plating or vapor-phase film-forming method (sputtering, ionization) on the surface of the resin substrate 11 Plating, electron beam vapor deposition, vacuum vapor deposition, chemical vapor deposition, etc.), and a method of vapor-depositing the metal circuit portion 13. From cost and productivity aspects In particular, the method of bonding the metal foil to the surface of the resin substrate 11 with the 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. The etching mask is provided so that the circuit pattern forming portion of the metal foil that will become the metal circuit portion 13 will not be corroded by the etching solution. The method of forming the etching mask is not particularly limited. For example, the etching mask can be formed on the surface of the laminate by developing a photoresist or dry film through a photomask and developing it, or by inkjet An etching mask is formed on the surface of the laminate by printing technology such as a printer.

Next, the metal foil that is not covered by the etching mask is removed by the immersion liquid. As a result, the portion of the metal foil other than the metal line portion 13 is removed.

Finally, use an alkaline stripping solution to remove the etching mask. As a result, the etching mask is removed from the surface of the metal line portion 13.

[Steps for forming insulating protective film and reflective layer]

After the metal line portion is formed, the insulating protective film 15 and the reflective layer 16 are further laminated as necessary. These buildups can be carried out by known methods. Depending on the material used, various lamination processing methods such as screen printing, dry lamination, and thermal lamination can be used.

<LED building module>

By directly mounting the LED element 2 on the metal circuit portion 13 of the LED element substrate 1, the LED mounting module 10 can be obtained.

The LED element 2 is a light-emitting element that utilizes light emission at a PN junction that is formed by joining a P-type semiconductor and an N-type semiconductor. There has been proposed a structure in which P-type electrodes and N-type electrodes are provided on the top and bottom surfaces of the device; and a structure in which both P-type and N-type electrodes are provided on one side of the device. Any LED element 2 of any structure can be used in the LED package module 10 of the present invention, but among the above, a structure in which both P-type and N-type electrodes are provided on one side of the element can be used particularly preferably LED components.

The LED mounting module 10 is, as described above, directly mounting the LED element 2 on the metal circuit portion 13 that can exhibit high heat dissipation. As a result, the heat generated by the LED element 2 during lighting will quickly spread to the entire metal circuit portion 13 and the heat dissipation of the LED package module 10 will be greatly improved.

The LED mounting module 10 of the present invention can mount at least 100 or more LED elements 2. The large-sized LED display device whose conversion of the screen size of the LED display device is approximately 32 inches or more can also be preferably used. In addition, in the manufacture of large display devices of approximately 32 inches or more, the circuit design of a large flexible substrate type LED element substrate 1 composed of a single resin is compared with the conventional combination of a plurality of small substrates of a fixed size, which is composed of a single resin The degree of freedom is high, so the arrangement interval and the like of the assembled LED elements 2 can be arbitrarily adjusted, and it is possible to respond to various physical properties required in a large-sized LED display device at a lower cost than in the past.

<Manufacturing method of LED building module>

The manufacturing method of the LED package module 10 using the substrate 1 for LED elements is demonstrated. The LED element 2 is connected to the metal line portion 13 The combination can be preferably performed by solder processing. This solder joint can be re-soldered or laser-based. In the reflow method, the LED element 2 is mounted on the metal circuit portion 13 via solder, and thereafter, the LED element substrate 1 is transported into the reflow furnace, and hot air at a predetermined temperature is blown to the metal circuit portion 13 in the reflow furnace , A method of melting the solder paste and soldering the LED element 2 to the metal line portion 13. In addition, the laser method means a method of soldering the LED element 2 to the metal circuit portion 13 by locally heating the solder with a laser.

When soldering the LED element 2 to the metal circuit portion 13, it is preferable to use a method of performing solder reflow by laser irradiation from the back side of the resin substrate 11. With this, it is possible to more reliably suppress the ignition of the organic component of the solder due to heating and the damage to the substrate accompanying it.

<LED display device>

FIG. 9 is a perspective view schematically showing the outline of the 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 images on the screen 3 by driving (emitting light) a plurality of LED elements 2 arranged in a matrix at predetermined intervals. The LED element 2 is mounted on the metal line portion 13 of the LED element substrate 1. Furthermore, it is more preferable that the heat dissipation structure 4 is provided on the back side of the resin substrate 11, and this heat dissipation structure 4 is used to further efficiently radiate the heat radiated from the LED package module 10 to the outside. By using the LED mounting module 10 of the present invention, for example, a large-sized LED display device with a screen size (diagonal length) of 32 inches or more can be manufactured at a lower cost and with improved quality stability.

According to the above-described LED element substrate, LED packaging module, etc. of the present invention and the LED display device using the same, the following effects will be exerted.

(1) The present invention is as follows: In the flexible substrate type LED element substrate 1 that reduces bending damage as a problem, the shape and arrangement of the metal wiring portion 13 are made of polygonal or circular conductive The plate portion 131 is configured to satisfy the condition that the non-conductive portion between the two adjacent conductive plate portions 131, that is, the insulating slit portion 132 and the other insulating slit portion 132 adjacent thereto are not on the same straight line. With this, it is possible to reduce the risk of bending damage caused by the flexibility of the base resin and the difference in the bending elastic coefficient of the base resin and the metal wiring portion in the substrate for a flexible substrate type LED element.

(2) The shape of the conductive plate portion in (1) is a regular hexagon. With this, the strength of the substrate 1 for LED elements against bending can be further improved, and the effect of reducing the risk of bending damage in the invention of (1) can be more stably exhibited.

(3) When the shape of the conductive plate portion in (1) is a circular shape, the arrangement of the metal line portion is such that the circular conductive plate portions 131 are arranged in a staggered shape. This can further improve the reliability of the LED element substrate 1 to exhibit the strength against bending, and more stably exhibit the effect of reducing the risk of bending damage in the invention of (1).

(4) In the present invention, it is assumed that the metal wiring portion 13 covers a range of 70% or more of one surface of the resin substrate 11. By this, can It is sufficient to improve the heat dissipation while maintaining the effect of improving the invention from (1) to (3).

(5) In the present invention, it is assumed that the metal wiring portion 13 covers a range of 95% or more of one surface of the resin substrate 11. Thereby, the heat dissipation can be further improved while maintaining the effect of improving the invention of (1) or (2).

(6) The substrate 1 for LED elements has a diagonal length of 32 inches or more and is composed of a single resin film. In this way, since a single LED element substrate 1 can be used to construct a large-scale LED display device that can only be formed by bonding a plurality of LED building modules, the productivity and quality stability of the LED display device can be significantly improved .

(7) The present invention is an LED display device 100 formed by layering the substrate 1 for LED elements described in (6) and a picture area for display. With this, it is possible to provide a large-sized LED display device 100 with a screen size of 32 inches or more with high productivity, and it has excellent quality stability.

As described above, according to the present invention, it is possible to provide a substrate for LED elements, which is a flexible substrate-type substrate for LED elements, wherein the risk of bending damage is reduced, and the bending damage is due to the flexibility of the resin substrate , And the difference between the bending elasticity coefficient of the resin substrate and the metal wiring part.

2‧‧‧LED components

13‧‧‧Metal Line Department

131A‧‧‧Conducting Board Department

132A, 132B, 132C, 132D

X, Y‧‧‧ direction

Claims (7)

A substrate for an LED element, comprising: a resin substrate composed of a flexible resin film; and a metal wiring portion formed on the resin substrate to be able to conduct LED elements, the LED elements being arranged in a matrix And the metal line portion is composed of a plurality of circular or polygonal conductive plate portions arranged on the resin substrate, and the non-conductive portion between the two adjacent conductive plate portions is one The insulating slit part is not on the same straight line as another adjacent insulating slit part. The substrate for an LED element according to claim 1, wherein the conductive plate portion is a regular hexagonal conductive plate portion. The substrate for an LED element according to claim 1, wherein the metal line portion is composed of a plurality of perfect circular or elliptical conductive plate portions arranged alternately on the resin substrate. The LED element substrate according to any one of claims 1 to 3, wherein the metal wiring portion covers a range of 70% or more of one surface of the resin substrate. The substrate for an LED element according to claim 1 or 2, wherein the metal wiring portion covers a range of 95% or more of one surface of the resin substrate. For LED elements as described in any of claims 1 to 3 The substrate, wherein the aforementioned resin substrate has a diagonal length of 32 inches or more and is composed of a single flexible resin film. An LED display device is formed by stacking an LED construction module and a display screen. The LED construction module is constructed by mounting an LED element on a substrate for an LED element according to any one of claims 1 to 3 Made.

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