JP2007214474A - Edgelight and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an edgelight capable of efficiently cooling light-emitting elements, and to provide a method of manufacturing the same. <P>SOLUTION: Lead frames 102 each having an unevenness and cut into a rod shape are integrated with a metal plate 110 in a state where they are insulated from each other via a heat conductive resin 104, the light-emitting elements 100 such as LEDs are each mounted on the cut surface for each line of the concave portions of the lead frames, thereby forming the edgelight. With this configuration, since heat emitted from the light-emitting elements 100 can be efficiently transmitted to the lead frames 102, the heat conductive resin 104 and the metal plate 110, heat radiating efficiency of the edgelight can be improved during light emission. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an edge light used for a backlight of a display device having a backlight such as a liquid crystal television 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 mounted on a heat-radiating substrate in a straight line because of the need for higher color rendering.

  FIG. 7 is a cross-sectional view showing an example of a conventional LED light emitting element. In FIG. 7, the light emitting element 2 is mounted in the 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. 7, the wiring in the ceramic substrate 1 having the recesses and the connection substrate 5, the LED wiring, and the like are not shown. Such edge lights 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. In addition, the light emitting element having such a structure is often mounted on the bottom of the heat dissipation substrate, and it is difficult to perform optical design for forming a parallel light source.

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-mentioned conventional problems, and instead of a ceramic substrate, a plurality of lead frames partially cut into a concavo-convex shape are used, and a heat conducting material in which an inorganic filler is dispersed in a thermosetting resin. An object of the present invention is to provide an edge light that can be easily optically designed and reduced in cost, and a method for manufacturing the same, by fixing with resin and mounting a light emitting element on the tips of the convex portions of the plurality of lead frames. .

  The edge light obtained by the edge light of the present invention and the manufacturing method thereof has a structure that efficiently diffuses the heat generated by the light emitting element such as an LED or a semiconductor laser, so that the light emitting element such as the LED can be effectively cooled. .

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

  FIG. 1 is a perspective view showing an edge light in the first embodiment. In FIG. 1, 100 is a light emitting element, 102 is a lead frame, 104 is a heat conducting resin, 106 is an arrow, 108 is a dotted line, and 110 is a metal plate. In FIG. 1, a predetermined uneven shape is formed by punching or the like on one side of the lead frame 102 (the side on which the light emitting element 100 is mounted), and the remaining one side is processed into a straight line (side facing the metal plate 110). Has been. A plurality of lead frames 102 of this shape are integrated by a heat conducting resin 104 so as to be parallel to each other. The light emitting element 100 is mounted on the cut surface of the lead frame 102 at the apex of the convex portion of the lead frame 102. A dotted line 108 indicates a position where the light emitting element 100 is mounted as indicated by an arrow 106d. And the light radiated | emitted from the light emitting element 100 mounted in the vertex of the convex part of the lead frame 102 is irradiated ahead of an edge light, as 106a shows. Further, light emitted from the light emitting element 100 to the side surface is reflected forward as indicated by an arrow 106 b due to the uneven shape of the lead frame 102. Further, the heat generated in the light emitting element 100 diffuses through the lead frame 102 as indicated by an arrow 106c. The heat of the lead frame 102 is transmitted to the metal plate 110 through the heat conductive resin 104 as indicated by the arrow 106c. Thus, the light emitting element 100 is cooled.

  The light-emitting element 100 is a light-emitting element such as an LED or a laser, 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. In the edge light shown in FIG. 1, a plurality of lead frames 102 and a metal plate 110 are integrated by a heat conductive resin 104, and a side surface of the lead frame 102 (or a plate-like lead frame material is made of gold). It has an uneven surface on its punched surface, which can be punched with a mold or the like. Then, the light emitting element 100 is mounted on the tip of the convex portion made of the lead frame 102 or the heat conductive resin 104.

  In this way, the light from the light emitting element 100 is efficiently reflected forward by a reflection portion provided in the periphery (corresponding to a convex portion formed by the lead frame 102 or the heat conductive resin 104 in the case of FIG. 1). As described above, part of the lead frame 102 and the heat conductive resin 104 can be a reflector that reflects the light emitted from the light emitting element 100 forward, and can further serve as a protection portion of the light emitting element 100.

  In FIG. 1, a lead frame 102 is obtained by processing (that is, cutting) a long plate material to be the lead frame 102 into a predetermined concavo-convex shape by a die (or press processing), etching, or the like. Here, the lead frame 102 is processed so as to have an uneven shape on one side of the rod shape, and has a thickness of 0.5 mm and a width of 0.5 to 2 mm (this is as shown in FIG. This is because it includes irregularities on one side surface) and has a rod-like shape having a length of 100 to 500 mm. A plurality of the lead frames 102 are fixed with a heat conductive resin 104 in a parallel state. The metal plate 110 can be integrally formed simultaneously with the lead frame 102.

  Thereafter, as shown in FIG. 1, the light emitting element 100 is mounted on the apex of the convex portion of the lead frame 102. For example, the thickness of the heat conductive resin 104 after molding shown in FIG. 1 is 0.5 mm, and the thickness of the lead frame (for example, thickness 0.5 mm, width 0.5 to 2 mm, length 100 to 500 mm) is 0. When the thickness is 0.5 mm, the width of the edge light shown in FIG. 1 is 0.5 mm × 2 + 0.5 mm = 1.5 mm. The height of the edge light is 0.5 to 2 mm. The basis for the edge light height of 2 mm is due to the lead frame (0.5 to 2 mm). And by mounting the light emitting element 100 on the apex of the convex part on the lower side of the lead frame 102 as shown in FIG. 1, the light emitted from the light emitting element 100 is projected on the adjacent lead frame 102 or the convex part of the heat conducting resin 104. Reflects efficiently in front of the lead frame. Thus, an edge light having a width of 1.5 mm, a height of 2 mm, and a length of 100 to 500 mm can be formed.

  Next, a case where the light emission stability of the light emitting element is improved will be described with reference to FIG.

  FIG. 2 is a perspective view illustrating a state in which a protection element and a reflector are attached to the edge light. In FIG. 2, 112 is a reflector and 114 is a protective element. In FIG. 2, the lead frame 102b is in a floating island state (meaning that the pattern is electrically floating from the lead frame 102a for power supply). In this way, by using the floating island-shaped lead frame 102b and connecting the light emitting element 100 to the lead frame 102a serving as a current supply source via the protective element 114, light emission of the light emitting element 100 can be stabilized. Here, a square chip resistor or the like can be used as the protection element 114. In this way, when the plurality of light emitting elements 100 are lit in a state of being connected in parallel, current can be supplied through the protection elements 114 in series with the individual light emitting elements 100.

  Here, the reason why the protective element 114 is inserted in series with the light emitting element 100 is to prevent the light emitting element 100 from being destroyed by applying excessive stress (temperature, current, voltage, etc.). As a result, the light emitting device 100 can be used at less than the absolute maximum rating. Further, by optimizing the protection element 114, it is possible to reduce the light emission variation among the plurality of light emitting elements 100.

  As shown in FIG. 2, by forming the floating island-shaped lead frame 102 b in a part of the edge light, a protection element or the like can be introduced into the edge light, so that the life of the light emitting element 100 can be extended. 2, dotted lines 108 indicate positions where the light emitting element 100 and the protective element 114 are mounted. The light emitting element 100 and the protective element 114 are arranged on the lead frames 102 a and 102 b as indicated by arrows 106. Will be implemented. Note that the light emitting element 100 and the protection element 114 do not have to be mounted on the same surface of the edge light. The light emitting element 100 may be mounted on the first side surface (for example, the upper surface) of the edge light, and the protection element 114 may be mounted on the second side surface (for example, the side surface) of the edge light. Needless to say, the shape, number, arrangement, etc. of the floating island-shaped lead frame 102b can be optimized according to the usage of the edge light.

  As described above, even when the protection element 114 is used, the light emitted from the light emitting element 100 can be used for various purposes such as the light emitted from the lighthouse by mounting the light emitting element 100 at a position where it is lifted by one step. It's easy to do. Specifically, as shown in FIG. 2, by setting the reflector 112 as indicated by an arrow 106, the light emitted from the light emitting element 100 can be reflected forward with the side surface of the reflector 112 as a reflecting surface.

  FIG. 3 is a perspective view showing an edge light using an uneven lead frame 102a. As shown in FIG. 3, an edge light can be formed by attaching a lead frame 102a bent in a concavo-convex shape and a plate-like lead frame 102b via a heat conductive resin 104a. As shown in FIG. 3, a convex portion is formed on one side of the edge light, and the light emitting element 100 is mounted at a position indicated by a dotted line 108a at the apex of the convex portion as indicated by an arrow 106a. Further, it is desirable to form the heat conducting resin 104b on the side of the lead frame 102b where the lead frame 102a is not formed. By forming the heat conductive resin 104b in this way, the lead frame 102a can be insulated, so that it is not necessary to insulate the lead frame 102a again when mounting on another member (not shown in FIG. 3). . In FIG. 3, a metal plate (for example, 110 in FIG. 1) is not shown under the heat conducting resin 104b, but a metal plate may be formed in this portion and fixed with the heat conducting resin 104b.

  Moreover, you may add the reflector 112 as needed. In addition to the trapezoid shown in FIG. 2, the reflector 112 may have a ring shape (or a donut shape). In addition, the shape of the side surface of the reflector 112 (the surface that reflects light from the light emitting element 100) can be narrowed toward the bottom, which is to increase the light reflection efficiency. It goes without saying that the light emission direction as the edge light can be optimized by making the side surface of the reflector 112 (the surface that reflects the light from the light emitting element 100 forward) a parabola, a quadratic curve, a cubic curve, or the like. Further, the reflector 112 may protrude from the edge light to the left and right.

  In FIG. 3, the protection element 114 can be mounted at the position of the dotted line 108b shown at the end of the lead frame. In this way, a single protection element 114 can cope with a plurality of light emitting elements 100 in series.

  Next, an example of an edge light manufacturing method will be described with reference to FIG. FIG. 4 is a perspective view showing a method for manufacturing an edge light. In FIG. 4A, a lead frame 102a is punched into a predetermined shape using a predetermined mold (not shown) and further bent into a predetermined uneven state. Then, the lead frame 102a bent so as to have the unevenness and the other lead frame 102b (the lead frame not bent in FIG. 4A) are set in a state where the heat conductive resin 104a is sandwiched in the middle. . It is desirable to set the heat conducting resin 104b on the side of the lead frame 102b that is not the lead frame 102a. This is to insulate the lead frame 102b from the underlying housing (not shown).

  Next, as indicated by an arrow 106a in FIG. 4A, the lead frames 102a and 102b and the heat conductive resins 104a and 104b are integrated using a mold (not shown). At this time, the object to be pressed is heated using a heat press, and the heat conducting resins 104a and 104b are softened and thermally cured in a state of being kept in a predetermined shape. The heat conducting resins 104a and 104b are preferably preformed in advance as shown in FIG. For example, by using a cylindrical shape (or an elliptical column shape), it is possible to prevent the occurrence of air remaining (or insufficient adhesion) in the gap between the heat conducting resins 104a and 104b and the lead frames 102a and 102b during pressing.

  FIG. 4B is a schematic diagram showing a state after the heat conducting resin is cured. In FIG. 4B, the lead frame 102a having projections and depressions is integrated with the lead frame 102b through a heat conductive resin 104a. Further, the lead frame 102b can be insulated by the heat conductive resin 104b formed on one side of the lead frame 102b.

  In the case of the structure of FIG. 4, the dimensions of the lead frame bent into an uneven state are desirably 0.5 mm to 5 mm in width and 10 mm to 500 mm in length. If the width is less than 0.5 mm, the width of the finished edge light may be less than 0.5 mm, making it difficult to handle. If the width exceeds 5 mm, it may be difficult to use as an edge light. Also, when the length is less than 10 mm, it may be difficult to use as an edge light. If the length exceeds 500 mm, the edge light may be easily deformed.

Note that it is desirable to use the heat conducting resin 104 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 104 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 104 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 conducting resin 104 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 104 having a thermal conductivity of 1 W / (m · K) or more and 20 W / (m · K) or less can be formed. When the thermal conductivity is less than 1 W / (m · K), the heat dissipation of the edge light is affected. 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 conductive resin 104 is reduced, the heat generated in the light emitting element 100 mounted on the lead frame 102 can be easily transferred to the metal plate 110, but conversely, the insulation breakdown voltage becomes a problem, and if it is too thick, the thermal resistance increases. In view of the withstand voltage and thermal resistance, the optimum thickness may be set to 50 microns or more and 1000 microns or less.

  As described above, in Embodiment 1, by adding a filler having good thermal conductivity as the heat conductive resin 104, heat conductivity and light reflectivity (the filler added to the heat conductive resin is white and highly light reflective). To increase).

  Note that the color of the heat conducting resin 104 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 104 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 and the heat conducting resin 104 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, the driving semiconductor component, the 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.

  It should be noted that the solder layer is previously applied to the surface of the lead frame 102 exposed from the heat conductive resin 104 (the light emitting element 100 or a mounting surface of a control IC or 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. It is desirable that no solder layer be formed on the surface (or embedded surface) of the lead frame 102 that is in contact with the heat conducting resin 104. When a solder layer or a tin layer is formed on the surface in contact with the heat conducting resin 104 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 conducting resin 104. . 1 and 2, the solder layer and the tin layer are not shown.

The metal metal plate 110 is made of aluminum, copper, or an alloy containing them as a main component with good thermal conductivity. In particular, in the present embodiment, the thickness of the metal plate 110 is set to 1 mm, but the thickness can be designed according to the specifications of the edge light (note that if the thickness of the metal plate 110 is 0.1 mm or less, heat dissipation and strength In addition, if the thickness of the metal plate 110 exceeds 5 mm, it is disadvantageous in terms of weight). The metal plate 110 is not only a plate-like one, but in order to increase heat dissipation, a fin portion (or uneven portion) is provided on the surface opposite to the surface on which the heat conducting resin 104 is laminated in order to increase the surface area. It may be formed. The linear expansion coefficient is 8 × 10 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C. By bringing the coefficient of linear expansion close to that of the metal plate 110 or the light emitting element 100, warpage and distortion of the entire edge light can be reduced. In addition, when these components are surface-mounted, matching the thermal expansion coefficients with each other is also important in terms of reliability. Further, the metal plate 110 may be fixed to another heat radiating plate or a housing (both 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.

  In the case of the structure of FIGS. 1 and 2, the length of the lead frame 102 is desirably 10 mm or more and 1 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 1 m, it may be difficult to handle. In the present invention, the thermal expansion coefficients of the plurality of lead frames 102 constituting the edge light are the same, so that the edge light is twisted or bent even when the temperature of the edge light rises due to heat generated from the light emitting element 100. Can be prevented. Moreover, the thermal expansion coefficient of the metal plate 110 can also be matched. Depending on the degree of heat dissipation, the metal plate 110 can be omitted.

  Note that the light emitting element 100 is desirably mounted on a cross-sectional portion of the lead frame 102. By mounting on the cross section of the lead frame 102, the edge light thickness can be made extremely thin. 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 the side surface of the edge light (or the non-mounting surface of the LED). In this way, it is possible to realize a thin layer of edge light, and to increase its strength, increase current, increase heat dissipation, and reduce costs.

  Note that in the configuration of the edge light, the presence or absence of the metal plate or the size thereof can be adjusted with the structure of FIGS. 1 to 4 in accordance with the amount of heat generated from the light emitting element 100.

(Embodiment 2)
Hereinafter, as Embodiment 2, a planar edge light will be described with reference to FIG. The edge light described with reference to FIGS. 1 to 4 is a one-dimensional (or rod-shaped) structure in which light-emitting elements are arranged in a row on an extremely fine rod-shaped heat dissipation member. On the other hand, an edge light having a certain width may be supplied from the market. FIG. 5 shows an example of such an edge light, in which a plurality of light-emitting elements are two-dimensionally arranged in a recessed portion at a high density, as shown in FIG.

  FIG. 5 is a top view and a cross-sectional view of the edge light. FIG. 5A is a top view of the edge light, and FIG. 5B is a cross-sectional view thereof. In FIG. 5A, a plurality of lead frames 102 are arranged radially at regular intervals and fixed in a state of being insulated from each other via a heat conductive resin 104. Note that dotted lines 108a and 108b in FIG. 5A correspond to the bent positions of the lead frame 102 in FIG. 5B. The plurality of lead frames 102 bend at the position indicated by the dotted line 108a (form a recess as shown in FIG. 5B), and protrude at the position indicated by the dotted line 108b (the light emitting element shown in FIG. 5B). The convex part which mounts 100) is formed.

  Next, description will be made with reference to FIG. FIG. 5B is a cross-sectional view at an arbitrary position in FIG. As shown in FIG. 5B, the lead frame 102 has a convex portion on which the light emitting element 100 is mounted at the center, and a plurality of light emitting elements 100 are mounted on the convex portion of the lead frame 102. . Light is emitted from the light emitting element 100 mounted on the apex of the convex portion of the lead frame 102 as indicated by an arrow 106a. Further, the light emitted from the light emitting element 100 to the side surface is reflected by the surface of the lead frame 102 and the heat conducting resin 104 processed into a concave shape as indicated by an arrow 106b, and the light emission efficiency as an edge light is enhanced. In this way, the optical design of the reflective surface (for example, the heat conductive resin 104 or the lead frame 102) can be facilitated by lifting the light emitting element 100 with the lead frame 102 as a kind of support (or support) and the light emitting element 100 upward. To do.

  FIG. 6 is a cross-sectional view showing an example of a method for manufacturing an edge light. FIG. 6A is a cross section of the lead frame 102a before being bent. Next, as shown in FIG. 6B, the lead frame 102a is processed into a lead frame 102b by a mold or the like. Here, the lead frame 102b is bent into a predetermined shape (as shown in FIG. 5, like a bowl shape or a shape of a pot used for potting). Then, as shown in FIG. 6B, a metal plate 110 is set under the lead frame 102b via the heat conductive resin 104. And as shown by the arrow 106a, these are heat-integrated using a metal mold | die and a hot press apparatus (both are not shown in figure). Then, the heat conducting resin 104 is thermoset. Here, it is desirable that the heat conductive resin 104 be preformed in advance as shown in FIG. As shown in FIG. 6B, by devising the shape of the heat conducting resin 104 in accordance with the shape of the lead frame 102b or the metal plate 110, it is possible to easily go into the details of the shape during hot pressing. In addition, pre-molding makes it difficult for air to remain between the heat conducting resin 104 and the lead frame 102b or the metal plate 110 during pressing.

  6C is a cross-sectional view after the lead frame 102b and the metal plate 110 are integrated by the heat conductive resin 104. FIG. Next, as shown in FIG. 6C, the light emitting element 100 is mounted on the convex portion of the lead frame 102b as indicated by an arrow 106b. Thus, an edge light as shown in FIGS. 5A and 5B can be manufactured.

  As described above, as shown in FIG. 1 and the like, a plurality of lead frames 102 including those partially cut into a concavo-convex shape and the plurality of lead frames 102 are fixed to be parallel to each other. Provided is an edge light comprising a heat conductive resin 104 in which an inorganic filler to be dispersed is dispersed in a thermosetting resin, and a light emitting element 100 mounted on the cut surface at the tip of the convex portion of the lead frame 102.

  Alternatively, a plurality of lead frames 102 including a part cut into a concavo-convex shape, a metal plate 110, and an inorganic filler for fixing the plurality of lead frames 102 and the metal plate 110 are dispersed in a thermosetting resin. An edge light including the heat conductive resin 104 thus formed and the light emitting element 100 mounted on the cut surface at the tip of the convex portion of the lead frame 102 is provided.

  Further, as shown in FIG. 3 or FIG. 5, a plurality of lead frames 102a and 102b including those bent at least partially so as to have irregularities (for example, the lead frame 102a in FIG. 3), and the plurality Edge composed of heat conductive resins 104a and 104b in which an inorganic filler for fixing the lead frames 102a and 102b is dispersed in a thermosetting resin, and a light emitting element 100 mounted on the tip of the convex portion of the lead frame 102a Provide light.

  Also, a plurality of lead frames 102a and 102b including at least a portion bent so as to have irregularities (for example, the lead frame 102a in FIG. 3), a metal plate 110, and the plurality of lead frames 102a and 102b. An edge light is provided, which includes heat conductive resins 104a and 104b in which an inorganic filler for fixing the resin is dispersed in a thermosetting resin, and a light emitting element 100 mounted on the tip of a convex portion of the lead frame 102a.

  Further, after the heat conducting resin 104 in which an inorganic filler is dispersed in a thermosetting resin is sandwiched between the plurality of lead frames 102, the heat is pressed and the lead frame 102 is integrated with the heat conducting resin 104. An edge light is manufactured by mounting the light emitting element 100 on the tip of the convex portion of the lead frame 102.

  In addition, the lead frame 102 and the metal plate 110 are heat-pressed in a state where a heat conductive resin 104 in which an inorganic filler is dispersed in a thermosetting resin is sandwiched between the plurality of lead frames 102 and the metal plate 110. After being integrated with the heat conductive resin 104, the edge light is manufactured by mounting the light emitting element 100 on the tip of the convex portion of the lead frame.

  As described above, by using the edge light according to the present invention, a large number of light emitting elements can be stably lit, so that the present invention can be applied to applications such as downsizing and high color rendering of liquid crystal display elements and lighting devices.

The perspective view which shows the edge light in Embodiment 1 The perspective view which shows a mode that a protection element and a reflector are attached to an edge light The perspective view which shows the edge light using the lead frame which has an unevenness | corrugation The perspective view which shows the manufacturing method of edge light Top view and sectional view of edge light Sectional view showing the manufacturing method of 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 Thermal conductive resin 106 Arrow 108 Dotted line 110 Metal plate 112 Reflector 114 Protection element

Claims (10)

A plurality of lead frames, including those partially cut into a concavo-convex shape;
A heat conductive resin in which an inorganic filler for fixing the plurality of lead frames so as to be parallel to each other is dispersed in a thermosetting resin;
A light emitting device mounted on the cut surface of the tip of the convex portion of the lead frame;
Edge light consisting of. A plurality of lead frames, including those partially cut into a concavo-convex shape;
A metal plate,
A heat conductive resin in which an inorganic filler for fixing the plurality of lead frames and the metal plate is dispersed in a thermosetting resin;
A light emitting device mounted on the cut surface of the tip of the convex portion of the lead frame;
Edge light consisting of. A plurality of lead frames including one bent at least partially so as to have irregularities;
A heat conductive resin in which an inorganic filler for fixing the plurality of lead frames is dispersed in a thermosetting resin;
A light emitting device mounted on the tip of the convex portion of the lead frame;
Edge light consisting of. A plurality of lead frames including one bent at least partially so as to have irregularities;
A metal plate,
A heat conductive resin in which an inorganic filler for fixing the plurality of lead frames is dispersed in a thermosetting resin;
A light emitting device mounted on the tip of the convex portion of the lead frame;
Edge light consisting of. The edge light according to any one of claims 1 to 4, wherein the heat conductive resin has a thermal conductivity of 1 W / (m · K) or more and 20 W / (m · K) or less. The inorganic filler contains at least one selected from the group consisting of Al ₂ O ₃ , MgO, BN, SiO ₂ , SiC, Si ₃ N ₄ , and AlN, according to claim 1. Edge light. The edgelight according to any one of claims 1 to 4, 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 edge light according to any one of claims 1 to 4, wherein: The lead frame is integrated with the heat conductive resin in a state where a heat conductive resin in which an inorganic filler is dispersed in a thermosetting resin is sandwiched between the plurality of lead frames, and then the lead frame is protruded. Manufacturing method of an edge light in which a light emitting element is mounted on the tip of a part. In a state where a heat conductive resin in which an inorganic filler is dispersed in a thermosetting resin is sandwiched between a plurality of lead frames and a metal plate, hot pressing is performed, and the lead frame and the metal plate are integrated with the heat conductive resin. A method for manufacturing an edge light, wherein a light emitting element is mounted on a tip of a convex portion of the lead frame.

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