JP2007214473A - Flexible edge light and manufacturing method thereof - Google Patents

Abstract

When a ceramic substrate is used as a heat dissipation substrate for an LED, it is difficult to process the ceramic substrate.
A plurality of elongated lead frames 102a and 102b are fixed at a plurality of positions separated by a certain distance, a heat conducting resin 106 is fixed, and a light emitting element 100 such as an LED is attached to a portion where the heat conducting resin 106 is formed. By mounting, a flexible edge light can be configured, and further, heat generated from the light emitting element 100 spreads through the lead frame 102 and the heat conducting resin 106, so that the heat dissipation efficiency at the time of light emission of the edge light can be enhanced. .
[Selection] Figure 1

Description

  The present invention relates to a flexible edge light used for a backlight of a liquid crystal television or the like and a manufacturing method thereof.

  Conventionally, as an edge light as a backlight of a liquid crystal television or the like (an edge light means a bar-shaped light that illuminates a side surface of a liquid crystal panel or a light guide plate set on the back surface of the liquid crystal panel, that is, from the edge). Cathode tubes and the like have been used. However, in recent years, there has been a demand for semiconductor light emitting devices such as LEDs and lasers that are linearly mounted on a heat-dissipating substrate because of the need for higher color rendering.

  FIG. 5 is a cross-sectional view showing an example of a conventional LED light emitting element. In FIG. 5, the light emitting element 2 is mounted in a recess formed in the ceramic substrate 1. The plurality of ceramic substrates 1 are fixed on the heat sink 3. Further, the plurality of ceramic substrates 1 are electrically connected by a connection substrate 5 having a window portion 4. The light 6 emitted from the LED is emitted to the outside through the window portion 4 formed on the connection substrate 5. In FIG. 5, the wiring on the ceramic substrate 1 having the recesses and the connection substrate 5, the wiring of the LEDs, and the like are not shown. Such light emitting modules are used as backlights for liquid crystals or edge lights.

  However, light emitting elements such as LEDs are easily affected by light emission efficiency, light emission color balance, and the like. Therefore, although cooling of the light emitting element is important, the ceramic substrate 1 is excellent in heat dissipation. However, since the processing is difficult and expensive, there has been a demand for a heat dissipation substrate that is cheaper and excellent in workability.

  Moreover, since such a light emitting module is being fixed to the heat sink 3 or the connection board | substrate 5, there was no flexibility and it was difficult to handle it.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2004-311791 A

  However, the conventional configuration has a problem that the heat dissipation substrate on which the light emitting element is mounted is a ceramic substrate, which is disadvantageous in terms of workability and cost.

  The present invention solves the above-described conventional problems, and instead of a ceramic substrate, an inorganic filler that fixes a plurality of lead frames at a plurality of positions separated by a certain distance is dispersed in a thermosetting resin. To provide a flexible edge light having a flexible structure and a manufacturing method thereof, which can be reduced in cost by the structure of a flexible edge light composed of a heat conductive resin and a light emitting element mounted on the cut surface of the lead frame. Objective.

  The flexible edge light obtained by the flexible edge light of the present invention and the manufacturing method thereof has a structure for efficiently diffusing heat generated by light emitting elements such as LEDs and semiconductor lasers, so that the light emitting elements such as LEDs are effectively used. Can be cooled.

(Embodiment 1)
Hereinafter, the flexible edge light in Embodiment 1 of this invention is demonstrated using FIG.

  FIG. 1 is a perspective view showing a flexible edge light according to Embodiment 1. FIG. In FIG. 1, 100 is a light emitting element, 102 is a lead frame, 104 is an arrow, 106 is a heat conducting resin, 108 is a dotted line, and 110 is a protective element. In FIG. 1, a plurality of lead frames 102 a and 102 b are cut long and thin, so as not to be short-circuited by the heat conductive resin 106 at a plurality of positions separated from each other by a predetermined distance in a state where they are arranged in parallel on the same plane. It is fixed to. The heat conducting resin 106 that fixes the plurality of lead frames 102a and 102b also fixes the floating island-shaped lead frame 102c. Here, when the lead frames 102a and 102b are power supply lead frames, the floating island-shaped lead frame 102c is fixed by the heat conductive resin 106 in a state of being electrically insulated from the power supply lead frames 102a and 102b. Yes. The plurality of lead frames 102a and 102b cut in this manner are fixed by a heat conductive resin 106 in which an inorganic filler is dispersed in a thermoplastic resin at a plurality of positions separated by a certain distance. As a result, the lead frames 102a and 102b that are not fixed by the heat conductive resin 106 can be made flexible, so that a flexible edge light can be formed. Here, by arranging a plurality of lead frames 102a and 102b on the same plane (preferably in parallel), the lead frames 102a and 102b can be bent as shown in FIG. , Since they bend while maintaining a certain distance from each other, they do not short-circuit each other. Note that “flexible” here means that if you try to bend it, it will bend, and it will be used for the backlight of the device rather than a flexible lead frame that can be used tens of thousands or hundreds of thousands of times while bending. As such, it can be used (or incorporated) in a narrow space by bending it as needed.

  FIG. 1A is a perspective view showing a state where the light emitting element 100 and the protection element 110 are mounted on the flexible edge light. In FIG. 1A, a plurality of lead frames 102a and 102b are fixed with a heat conducting resin 106 at a plurality of positions in a state where they are parallel to each other so as not to short-circuit each other on the same plane. The plurality of lead frames 102a and 102b in the portion where the heat conductive resin 106 is not formed have flexibility and can be freely bent as shown in FIG.

  In FIG. 1A, one end of a light emitting element 100a is connected to a lead frame 102a, and the other end is connected to a floating island-shaped lead frame 102c. One end of the protection element 110a is connected to the floating island-shaped lead frame 102c, and the other end is connected to the lead frame 102b. Here, by using the lead frames 102a and 102b as power supply lead frames, current is supplied to the light emitting element 100a and the protection element 110a connected in series via the lead frames 102a and 102b. Light is emitted from the light emitting element 100a as indicated by an arrow 104a.

  In FIG. 1A, taking the light emitting element 100b as an example, one end thereof is connected to a lead frame 102b and the other end is connected to a floating island-shaped lead frame 102c. One end of the protection element 110b is connected to the floating island-shaped lead frame 102c, and the other end is connected to the lead frame 102a. Taking the light emitting element 100b as an example, current is supplied through the lead frames 102a and 102b, and light emitted from the light emitting element 100b is emitted forward as indicated by an arrow 104b.

  FIG. 1B is a perspective view illustrating a state where the light-emitting element 100 and the protection element 110 in FIG. 1A are omitted. From FIG. 1B, it can be seen that the plurality of lead frames 102a and 102b are insulated by the heat conductive resin 106 so as not to short-circuit each other. It can be seen that the portions of the lead frames 102a and 102b that are not fixed by the heat conductive resin 106 have flexibility as shown in FIG. Here, when the lead frames 102a and 102b are fixed by the heat conductive resin 106, the floating island-shaped lead frame 102c is fixed at the same time, thereby protecting the light emitting element 100 in series as shown in FIG. Elements 110a and 110b can be connected.

  A dotted line 108 in FIG. 1B indicates a position where the light-emitting element 100c and the protection element 110c are mounted. A flexible edge light is manufactured by mounting the light emitting element 100c and the protection element 110c at a position indicated by a dotted line 108 as indicated by an arrow 104c.

  In the flexible edge light described above, by using the lead frames 102a and 102b for power feeding, the plurality of light emitting elements 100a and 100b can be stably lit at a maximum rating or less.

  FIG. 2 is a top view of the flexible edge light in the first embodiment. In FIG. 2, it can be seen that a plurality of light emitting elements 100 are mounted via the lead frame 102. In FIG. 2, a heat conductive resin 106 and a floating island-shaped lead frame 102 c are formed under the light emitting element 100 as shown in FIG. 1, but both are hidden behind the light emitting element 100 in FIG. 2. I can't see it. In FIG. 2, a plurality of lead frames (for example, the lead frames 102 a and 102 b shown in FIG. 1) are collected as the lead frame 102. Thus, since the portion (that is, the portion where the light emitting element 100 is mounted) of the flexible edge light in Embodiment 1 formed by the heat conductive resin 106 can be made substantially the same size as the light emitting element 100, more A flexible edge light that can be made thinner can be provided. Needless to say, the portion formed by the heat conductive resin 106 (that is, the portion where the light emitting element 100 is mounted) can be made smaller or larger than the light emitting element depending on the application.

  FIG. 2A is a top view for explaining the operation of the flexible edge light. In FIG. 2A, a current is supplied to a lead frame 102 composed of a plurality of leads (in FIG. 2A, the lead frame 102 is not shown in the plurality of leads) and connected to the lead frame 102. The plurality of light emitting elements 100 emit light and emit light as indicated by an arrow 104a. Further, as shown in FIG. 2A, since the plurality of light emitting elements 100 are connected via the lead frame 102, the portion of the lead frame 102 that is not fixed by the heat conductive resin 106 (that is, the light emitting element 100 is not connected). It can be bent freely at the part that is not mounted). As a result, as shown in FIG. 2 (A), the lead frame 102 of the present invention can be wound in a spiral shape (and further bent in a zigzag manner as shown in FIG. 2 (B)).

  2B is a partially enlarged view of the flexible edge light of FIG. 2A, and FIG. 2B shows a state in which heat generated from the light emitting element 100 spreads through the lead frame 102. FIG. It is. 2B, the heat conductive resin 106 and the lead frame 102c as shown in FIGS. 1A and 1B are hidden under the light emitting element 100 (visible in FIG. 2B). Absent). The heat generated in the light emitting element 100 is transmitted to the lead frame 102 via the heat conductive resin 106 (not visible in FIG. 2), and further spreads on the lead frame 102 as indicated by an arrow 104b. The heat transmitted on the lead frame 102 is naturally cooled on the lead frame 102.

  Further, by arranging the plurality of lead frames 102 on the same plane, even if the plurality of lead frames 102 are bent at the same time, they are not short-circuited with each other. Therefore, as shown in FIG. 2B, it is bent into a curved shape or bent into an acute angle (or zigzag).

  In this way, the entire edge light can be made flexible by electrically connecting the light emitting elements 100 by the lead frames 102a and 102b. Even when the entire flexible edge light of the present invention expands and contracts due to heat generation of the light emitting element 100, the stress due to the thermal expansion can be alleviated by creating play portions in the lead frames 102a and 102b. It is also effective to match the thermal expansion coefficients of the plurality of lead frames 102a and 102b.

  2A and 2B, the lead frame 102 can be a single strip (for example, a thickness of 0.5 mm, a width of 1 mm, and a length of 1 to 20 m). As shown in FIG. 1 (A) and FIG. 1 (B), for example, at a pitch of 10 mm on the long lead frame 102 (the above-mentioned thickness 0.5 mm, width 1 mm, length 1 to 20 m). A long flexible edge light can be manufactured by forming a block (for example, height 2 mm, width 2 mm, depth 2 mm, which corresponds to the mounting portion of the light emitting element 100 shown in FIG. 1 and the like) using a heat conductive resin.

  Here, the reason why the protective element 110 is placed in series with the light emitting element 100 is to prevent the light emitting element 100 from being damaged by applying excessive stress (temperature, current, voltage, etc.). Thus, by connecting the protection element 110 in series with the light emitting element 100, the light emitting element 100 can be used with less than the absolute maximum rating. Further, by optimizing the characteristics (or values) of the protection element 110, it is possible to reduce the light emission variation among the plurality of light emitting elements 100.

  As described above, in FIGS. 2A and 2B, the life of the edge light can be easily designed by forming the floating island-shaped lead frame 102c on a part of the heat conductive resin 106 constituting the flexible edge light. It becomes. Note that the light emitting element 100 and the protection element 110 need not be mounted on the same surface of the flexible edge light. As shown in FIG. 1A, the light emitting element 100a may be mounted on the first side surface (for example, the upper surface) of the flexible edge light, and the protection element 110a may be mounted on the second side surface (for example, the side surface) of the flexible edge light. Further, as shown in FIG. 1A, the light emitting element 100b may be mounted on the side surface of the flexible edge light, and the protection element 110b may be mounted on the upper surface of the flexible edge light. Needless to say, the shape, number, arrangement, etc. of the floating island-shaped lead frame 102c can be optimized in accordance with the use application of the edge light.

  Next, an example of a method for manufacturing a flexible edge light will be described with reference to FIGS. 3-4 is a perspective view which shows the manufacturing method of a flexible edge light. In FIG. 3A, reference numeral 112 denotes a lead frame material, which is punched from a long lead frame base material (not shown) into a predetermined shape with a die or the like. In FIG. 3A, for example, the lead frame material 112 is cut into a thickness (wall thickness) of 0.5 mm, a width of 1 mm, and a length of 1 to 20 m. This is the lead frame material 112 in FIG. Next, a cut is made in a part of the lead frame material 112. As shown in FIG. 3B, the lead frame material 112 is processed into a predetermined shape, whereby the lead frame 102 as shown in FIG. 3C is obtained. A die can be used for this processing (or punching with a press or the like). Next, as indicated by an arrow 104 in FIG. 3B, a part of the lead frame material 112 is bent. A part of the lead frame 102 formed in this way is bent as shown in FIG.

  Next, as shown in FIG. 4A, a heat conducting resin 106 and a continuous lead frame 102b (for example, a thickness of 0.5 mm, a width of 1 mm, a length of 1 to 1) are formed on a partially bent lead frame 102a. 20 m, which is preferably aligned with the lead frame 102a, so that it is difficult to short-circuit each other when bent or affected by heat generation, and a piece-like lead frame 102c (for example, Set the wall thickness 0.5mm, width 1mm, length 1-2mm). Then, as shown in FIG. 4A, a piece of heat conductive resin 106 is set between the three types of lead frames 102a, 102b, and 102c. Here, the heat conductive resin 106 may be, for example, one obtained by finely cutting a cylinder extruded (or one preliminarily molded into a certain shape). In this manner, the heat conductive resin 106 is cut into a predetermined size in advance, and the shape (at least the cross-sectional shape) is preliminarily molded into a circle (or an ellipse), so that the heat conductive resin 106 and the lead frames 102a, 102b, Generation of air residue (sometimes referred to as voids) can be prevented during 102c, and the dimensional variation of the portion formed by the heat conductive resin 106 (that is, the portion where the light emitting element 100 is mounted) can be suppressed. In this state, as indicated by an arrow 104 in FIG. 4A, these are heated and pressed using a predetermined mold (the mold is not shown). In FIG. 4, an arrow 104 means pressing, and it goes without saying that the pressing direction is up, down, left and right, and from the optimum direction. It is also effective to divide this pressing process into multiple times.

  FIG. 4B is a perspective view showing a state after the press is completed. In FIG. 4, it can be seen that the lead frames 102 a, 102 b and 102 c are integrated by the heat conductive resin 106.

  The light emitting elements 100a and 100b are mounted on the cut surfaces of the lead frames 102a and 102b shown in FIG. 4B (that is, corresponding to the thick portions of the lead frames 102a and 102b) as shown in FIG. Thus, the heat conductive resin 106 and the floating island-shaped lead frame 102c can be reduced to substantially the same size (or mounting area) as the light emitting element 100. As a result, as shown in FIG. 2, in the top view of the flexible edge light, the heat conductive resin 106 and the floating island-shaped lead frame 102 c can be hidden behind the light emitting element 100.

  Note that the lead frame 102 is subjected to a bending process as shown in FIG. 3C, whereby the bonding accuracy, adhesive strength, and molding accuracy of the lead frame 102 and the heat conductive resin 106 can be increased. Further, by bending a part of the lead frame 102 or directly connecting one end of the light emitting element 100 to the lead frame 102 by soldering or the like, heat generated in the light emitting element 100 can be easily radiated.

  The light-emitting element 100 is a light-emitting element such as an LED or a laser, and is, for example, a chip-shaped light-emitting element (the chip-shaped refers to a state where the light-emitting element is resin-sealed and a predetermined external electrode is attached. ) Or a bare chip.

As the heat conducting resin 106, it is desirable to use a resin in which a highly heat dissipating inorganic filler is dispersed in a curable resin. The inorganic filler has a substantially spherical shape, and its diameter is suitably from 0.1 to 100 microns (if it is less than 0.1 microns, it becomes difficult to disperse in the resin, and if it exceeds 100 microns, the heat conductive resin 106 is used. Increases the thickness of the material, affecting the thermal diffusivity). Therefore, the filling amount of the inorganic filler in the heat conducting resin 106 is filled at a high concentration of 70 to 95% by weight in order to increase the thermal conductivity. In particular, in the present embodiment, the inorganic filler is a mixture of two types of Al ₂ O ₃ having an average particle size of 3 microns and an average particle size of 12 microns. By using the Al ₂ O ₃ of the large and small two types of particle size, it is possible to fill the Al ₂ O ₃ of small particle size in the gap Al ₂ O ₃ of large particle size, Al ₂ O ₃ 90 wt% near Can be filled to a high concentration. As a result, the thermal conductivity of the heat conductive resin 106 is about 5 W / (m · K). The inorganic filler may include at least one selected from the group consisting of MgO, BN, SiO ₂ , SiC, Si ₃ N ₄ , and AlN instead of Al ₂ O ₃ .

When an inorganic filler is used, heat dissipation can be improved, but when using MgO in particular, the linear thermal expansion coefficient can be increased. Further, when SiO ₂ is used, the dielectric constant can be reduced, and when BN is used, the linear thermal expansion coefficient can be reduced. In this way, a heat conductive resin 106 having a thermal conductivity of 1 W / (m · K) or more and 20 W / (m · K) or less can be formed. In addition, when heat conductivity is less than 1 W / (m * K), it influences the heat dissipation of a light emitting module. Moreover, when it is going to make thermal conductivity higher than 20 W / (m * K), it is necessary to increase the amount of fillers and may affect the workability at the time of a press.

  The thermosetting insulating resin contains at least one kind of resin among epoxy resin, phenol resin and cyanate resin. These resins are excellent in heat resistance and electrical insulation. If the thickness of the heat conducting resin 106 is reduced, the heat generated in the light emitting element 100 attached to one lead frame 102 can be easily transferred to the other lead frame 102. Since the thermal resistance increases, the optimum thickness may be set to 50 microns or more and 1000 microns or less in consideration of the withstand voltage and the thermal resistance.

  As described above, by adding a filler having good thermal conductivity as the heat conductive resin 106, heat conductivity and light reflectivity (by making the filler to be added to the heat conductive resin white highly reflective). Will increase.

  Note that the color of the heat conductive resin 106 is desirably white. This is because when the color is black, red, blue, or the like, it is difficult to reflect the light emitted from the light emitting element, which affects the light emission efficiency.

  When soldering to the cut surface of the lead frame 102 or the like, it can be covered with a solder resist or the like so that the solder does not flow too much. Further, instead of the solder resist, the heat conductive resin 106 may be formed on a portion of the lead frame 102 where the lead frame 102 is not desired to be soldered. This can be dealt with by devising the shape of the lead frame 102 (for example, it is partially recessed so that the heat conducting resin 106 wraps around it).

  Next, the material of the lead frame 102 will be described. The lead frame is preferably made mainly of copper. This is because copper has both excellent thermal conductivity and electrical conductivity. In order to improve the workability and thermal conductivity as a lead frame, the copper material used as the lead frame 102 is selected from a group of at least Sn, Zr, Ni, Si, Zn, P, Fe, etc. other than copper. It is desirable to use an alloy comprising at least one material. For example, an alloy (hereinafter referred to as Cu + Sn) in which Cu is a main component and Sn is added thereto can be used. In the case of a Cu + Sn alloy, for example, by adding Sn to 0.1 wt% or more and less than 0.15 wt%, the softening temperature can be increased to 400 ° C. For comparison, when the lead frame 102 was made using Sn-free copper (Cu> 99.96 wt%), the electrical conductivity was low, but in the completed heat dissipation board, distortion may occur particularly in the formation portion. It was. Therefore, when the material was examined in detail, the softening point of the material was as low as about 200 ° C., so when the component was later mounted (soldering) or when reliability was confirmed after mounting the light emitting device 100 (repetition test of heat generation / cooling). Etc.). On the other hand, when a copper-based material with Cu + Sn> 99.96 wt% was used, it was not particularly affected by the heat generated by various mounted components and a plurality of LEDs. There was no effect on solderability and die bondability. Therefore, when the softening point of this material was measured, it was found to be 400 ° C. Thus, it is desirable to add some elements mainly composed of copper. In the case of Zr as an element added to copper, a range of 0.015 wt% or more and 0.15 wt% or less is desirable. When the amount added is less than 0.015 wt%, the effect of increasing the softening temperature may be small. On the other hand, if the amount added is more than 0.15 wt%, the electrical characteristics may be affected. Also, the softening temperature can be increased by adding Ni, Si, Zn, P or the like. In this case, Ni is preferably 0.1 wt% or more and less than 5 wt%, Si is 0.01 wt% or more and 2 wt% or less, Zn is 0.1 wt% or more and less than 5 wt%, and P is preferably 0.005 wt% or more and less than 0.1 wt%. . And these elements can make the softening point of a copper raw material high by adding single or multiple in this range. In addition, when there are few addition amounts than the ratio described here, the softening point raise effect may be low. Moreover, when there are more than the ratio described here, there exists a possibility of affecting the electrical conductivity. Similarly, in the case of Fe, 0.1 wt% or more and 5 wt% or less is desirable, and in the case of Cr, 0.05 wt% or more and 1 wt% or less are desirable. These elements are the same as those described above.

The tensile strength of the copper alloy used for the lead frame 102 is desirably 600 N / mm ² or less. In the case of a material having a tensile strength exceeding 600 N / mm ² , the workability of the lead frame 102 may be affected. Further, such a material having a high tensile strength tends to increase its electric resistance, so that it may not be suitable for high current applications such as LEDs used in the first embodiment. On the other hand, by setting the tensile strength to 600 N / mm ² or less (and if the lead frame 102 requires fine and complicated processing, desirably 400 N / mm ² or less), the springback (pressure even if bent to the required angle) If it is removed, it will be repelled by the reaction force), and the formation accuracy can be improved. As described above, as the lead frame material, the conductivity can be lowered by mainly using Cu, and the workability can be improved by further softening, and the heat dissipation effect by the lead frame 102 can also be enhanced. The tensile strength of the copper alloy used for the lead frame 102 is desirably 10 N / mm ² or more. This is because the copper alloy used for the lead frame 102 needs to have a strength higher than the tensile strength (about 30 to 70 N / mm ² ) of general lead-free solder. When the tensile strength of the copper alloy used for the lead frame 102 is less than 10 N / mm ² , when the light emitting element 100, a driving semiconductor component, a chip component, or the like is soldered and mounted on the lead frame 102, the lead frame is not the solder portion. There is a possibility of cohesive failure at 102 parts.

  A solder layer is previously applied to the surface of the lead frame 102 exposed from the heat conductive resin 106 (the light emitting element 100 or a mounting surface of a control IC or a chip component (not shown)). By forming the tin layer, it is possible to improve the component mountability to the lead frame 102 which has a larger heat capacity than the glass epoxy substrate or the like and is difficult to be soldered, and to prevent the wiring from being rusted. Note that it is desirable not to form a solder layer on the surface (or embedded surface) of the lead frame 102 that contacts the heat conductive resin 106. When a solder layer or a tin layer is formed on the surface in contact with the heat conductive resin 106 in this way, this layer becomes soft during soldering, which may affect the adhesion (or bond strength) between the lead frame 102 and the heat conductive resin 106. . In FIG. 1 and FIG. 2, the solder layer and the tin layer are not shown.

  As the lead frame 102, a metal plate mainly made of copper, at least a part of which is punched in advance, can be used. The thickness of the lead frame 102 is preferably 0.1 mm or more and 1.0 mm or less (more preferably 0.3 mm or more and 0.5 mm or less). This is because a large current (for example, 30 A to 150 A, which may further increase depending on the number of LEDs to be driven) is required to control the LEDs. Further, when the thickness of the lead frame 102 is less than 0.10 mm, pressing may be difficult. Further, if the thickness of the lead frame 102 exceeds 1 mm, pattern miniaturization may be affected when punching with a press. Also, it may affect the width and height (or miniaturization) of the edge light. Here, it is not desirable to use a copper foil (for example, a thickness of 10 microns or more and 50 microns or less) instead of the lead frame 102. In the case of the present invention, heat generated in the LED is diffused widely through the lead frame 102. Therefore, the greater the thickness of the lead frame 102, the more effective the thermal diffusion through the lead frame 102. On the other hand, when a copper foil is used in place of the lead frame 102, the thickness of the copper foil is thinner than that of the lead frame 102, which may make it difficult for heat diffusion.

  The length of the lead frame 102 is desirably 10 mm or more and 100 m or less. If the length of the lead frame is less than 10 mm, the cost merit as an edge light may not be obtained. If the length of the lead frame 102 exceeds 100 m, it may be difficult to handle. Still, since the flexible lead frame 102 of the present invention can be wound around a large reel device as a kind of hoop material, it can be handled even if it exceeds 100 m if it is devised. And if necessary, it is easy to make flexible edge lights of any length by cutting 5 m or 10 m. In the present invention, by making the thermal expansion coefficients of the plurality of lead frames 102 constituting the flexible edge light the same, even when the temperature of the edge light rises due to heat generated from the light emitting element 100, the flexible edge light is twisted, Needless to say, it can be prevented from bending.

  The light emitting element 100 can be mounted on a cross-sectional portion of the lead frame 102. By mounting on the cross-sectional portion of the lead frame 102 (corresponding to the thickness of the lead frame punched out with a die or the like, or a thick portion, or the thickness of the lead frame), the thickness of the flexible edge light can be further reduced. . In particular, the flexible edge light of the present invention has a plurality of lead frames 102a and 102b arranged in parallel to each other on the same plane as shown in FIGS. Are difficult to touch each other. Further, an insulator may be inserted between the lead frames 102a and 102b as necessary. In this case, it is desirable to use a material having good thermal conductivity or a flexible material as the insulator.

  Further, the non-cut surface of the lead frame 102 (the so-called front surface or back surface of the lead frame 102) can be used as the side surface of the flexible edge light (or the non-mounted surface of the LED). In this way, it is possible to realize a thin layer of the edge light, and it is possible to increase the strength, increase the current, increase the heat dissipation, and reduce the cost.

  Although the protective element 110 can be omitted depending on the design of the electric circuit, in order to stabilize the light emission of the light emitting element 100, the light emitting elements 100a and 100b are connected in series as shown in FIG. It is desirable to insert the protection elements 110a and 110b in series. In addition, the optimized design of the protection element 110 can apparently suppress variations in the light emission characteristics (color tone, color temperature, color balance, current-voltage characteristics, light emission efficiency, etc.) of the plurality of light emitting elements 100.

  An inorganic filler that fixes the plurality of lead frames 102a and 102b, which are cut long and thin on the same plane as described above, and the plurality of lead frames 102a and 102b at a plurality of positions separated by a certain distance. Provided is a flexible edge light comprising a heat conductive resin 106 dispersed in a thermosetting resin and a light emitting element 100 mounted on the cut surfaces of the lead frames 102a and 102b.

  The dimensions for cutting the lead frames 102a and 102b into an elongated shape are preferably 0.5 mm to 10 mm in width and 10 mm in length. When the width is less than 0.5 mm, it may be difficult to process the lead frame. If the width exceeds 10 mm, the use as an edge light may be limited. In addition, when the length is less than 10 mm, the length of the finished edge light is less than 10 mm, so that its application is limited. Further, by mounting the light emitting element 100 and the protective element 110 on the cut surface, the edge light can be thinned.

  The heat conducting resin 106 has a thermal conductivity of 1 W / (m · K) or more and 20 W / (m · K) or less, and a part of the heat conducting resin 106 has a floating lead frame (for example, FIG. 1A). By embedding one or more lead frames 102c), the protection element 110 and the like can be mounted at the same time, and the usability of the flexible edge light can be improved.

  As described above, by using the flexible edge light according to the present invention, it is possible to stably attach a large number of light emitting elements while improving the attachment property to various devices. It can be applied to applications such as high color rendering.

The perspective view which shows the flexible edge light in Embodiment 1. FIG. Top view of flexible edge light in embodiment 1 The perspective view which shows the manufacturing method of a flexible edge light The perspective view which shows the manufacturing method of a flexible edge light Sectional drawing which shows an example of the conventional LED light emitting element

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Light emitting element 102 Lead frame 104 Arrow 106 Heat conduction resin 108 Dotted line 110 Protection element 112 Lead frame material

Claims (6)

A plurality of lead frames that are elongated and aligned on the same plane;
Fixing the plurality of lead frames at a plurality of positions separated by a certain distance, a heat conducting resin in which an inorganic filler is dispersed in a thermosetting resin, and a light emitting element mounted on the cut surface of the lead frame,
Flexible edge light consisting of The heat conducting resin has a thermal conductivity of 1 W / (m · K) or more and 20 W / (m · K) or less, and at least one floating island state lead frame is embedded in a part of the heat conducting resin. The flexible edge light according to 1. _2. The flexible edge light according to claim 1, wherein the inorganic filler includes at least one selected from the group consisting of Al ₂ O ₃ , MgO, BN, SiO ₂ , SiC, Si ₃ N ₄ , and AlN. The flexible edge light according to claim 1, wherein the thermosetting resin includes at least one selected from the group consisting of an epoxy resin, a phenol resin, and an isocyanate resin. Sn is 0.1 wt% to 0.15 wt%, Zr is 0.015 wt% to 0.15 wt%, Ni is 0.1 wt% to 5 wt%, Si is 0.01 wt% to 2 wt%, Zn is Lead frame mainly composed of copper containing at least one selected from the group of 0.1 wt% to 5 wt%, P is 0.005 wt% to 0.1 wt%, and Fe is 0.1 wt% to 5 wt%. The flexible edge light according to claim 1, wherein: The lead frame is integrated with the heat-conducting resin after heat-pressing in a state where a heat-conducting resin in which an inorganic filler is locally dispersed in a thermosetting resin is sandwiched between a plurality of lead frames, and then the lead A method for manufacturing a flexible edge light, wherein a light emitting element is mounted on a portion of a frame fixed with a heat conductive resin.

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