JP5103841B2 - Light emitting module and backlight device using the same - Google Patents

Description

  The present invention relates to a light emitting module used for a backlight such as a thin display or a thin illuminating device, a manufacturing method thereof, and a backlight device using the same.

  Conventionally, a cold cathode tube or the like has been used for a backlight of a liquid crystal television or the like, but in recent years, it has been proposed to mount a semiconductor light emitting element such as an LED or a laser on a heat dissipating substrate ( For example, see Patent Document 1).

  FIG. 12 is a cross-sectional view showing an example of a conventional light emitting module. In FIG. 12, a light emitting element 102 is mounted in a recess formed in the ceramic substrate 101. Further, the plurality of ceramic substrates 101 are fixed on the heat radiating plate 103, and the plurality of ceramic substrates 101 are electrically connected by a connection substrate 105 having a window portion 104. The direction 106 of light emitted from the light emitting element 102 is emitted to the outside through the window 104 formed in the connection substrate 105. In FIG. 12, the wiring in the ceramic substrate 101 having the recesses and the connection substrate 105, the wiring pattern of the light emitting element 102, and the like are not shown.

  The light emitting module having such a configuration is used as a backlight for a liquid crystal display or the like.

On the other hand, from the display device side such as a liquid crystal TV, the color display range is expanded, the luminance of the light emitting element is further increased (a large current needs to flow), and a large number of light emitting elements are mounted at high density. There is a demand for a light emitting module with excellent heat dissipation.
JP 2004-311791 A

However, in the conventional configuration, since the substrate on which the light emitting element is mounted is the ceramic substrate 101, there is a problem that it is disadvantageous in workability and heat dissipation, and the present invention solves the conventional problem. Instead of the ceramic substrate 101, a light emitting module excellent in heat dissipation and high brightness by using a lead frame, an insulator excellent in thermal conductivity, and a metal substrate are integrated and used. An object is to provide a backlight device .

In order to solve the above-mentioned problems, the present invention directly mounts a light emitting element such as an LED on a lead frame that is excellent in heat dissipation and light reflectivity, performs heat dissipation by the lead frame, and further heats the lead frame. Is transmitted to a heat-dissipating metal substrate formed on the back surface through a thermally conductive resin provided with a uniform thickness .

The light emitting module obtained by the light emitting module of the present invention and the backlight device using the same condenses light emitted by light emitting elements such as LEDs and semiconductor lasers in the same direction, and generates generated heat as a lead frame. Since it is possible to efficiently diffuse and dissipate heat with a metal substrate, it is possible to realize a small light emitting module with excellent heat dissipation and light emission efficiency, and furthermore, by constructing a backlight device using this light emitting module, heat dissipation is achieved . It is possible to realize a backlight device that is excellent in thin liquid crystal display.

(Embodiment 1)
Hereinafter, the light emitting module and the manufacturing method thereof according to Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a configuration of a light emitting module according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of the light emitting module of FIG.

  1 and 2, reference numeral 1 denotes a lead frame having excellent thermal conductivity, such as copper. The lead frame 1 is composed of a lead frame 1a as an anode electrode and a lead frame 1b as a ground electrode. Reference numeral 2 denotes a heat conductive resin made of a composite material such as an inorganic filler having an excellent heat conductivity and an epoxy resin, and the heat conductive resin 2 includes a metal substrate 3 having a high heat conductivity. It is joined.

  Reference numeral 8 denotes an LED that emits red, blue, green, white, or the like. Reference numeral 4 denotes an arrow that indicates a traveling direction of light emitted from the LED 8. The LED 8 is shown as an example of a light emitting element such as a semiconductor laser, and it goes without saying that it can be applied to other light emitting elements.

  Furthermore, the lead frame 1a is individually divided so as to be compatible with the LED 8 having any characteristics. In this way, by configuring the lead frame 1a as an individual divided electrode structure, the applied voltage or applied current to the LED 8 can be individually controlled, so that the luminance can be individually controlled.

  When the LEDs 8 are selected and used in advance, the lead frame 1a can have a common electrode structure in the same manner as the lead frame 1b, thereby realizing a light emitting module with better heat dissipation. it can.

  The lead frames 1a and 1b are fixed in an insulated state on the metal substrate 3 so as to be embedded in the heat conductive resin 2, and the lead frames 1a and 1b are interposed via the heat conductive resin 2. Are insulated from each other. And since this heat conductive resin 2 is excellent in insulation and heat conductivity, the heat | fever discharge | released from LED8 can be diffused and radiated without concentration of heat_generation | fever occurring.

  Next, by bending the lead frames 1a and 1b into a tapered shape, a recess 6 as shown in FIG. 2 is formed, and the LED 8 has bump electrodes 9 extending over the lead frame 1a and the lead frame 1b. Has been implemented through.

  The LED 8 can be mounted by wire bonding or flip chip mounting using conductive resin, solder, or the like, but can be appropriately selected and mounted.

  In this way, the lead frames 1a and 1b are bent into a taper shape, and the light emitted from the LED 8 is directed in a predetermined direction through the lead frames 1a and 1b by designing the lead frames 1a and 1b to have as large an area as possible. By reflecting light, a light emitting module having excellent light emission efficiency can be realized.

  At this time, the lead frames 1a and 1b are formed of a metal material mainly composed of copper, which has excellent heat dissipation, so that the lead frame 1 exhibits an effect as an electrode, a light reflector and a heat sink. Thus, a small light emitting module with excellent luminous efficiency can be realized.

  Further, by forming a reflective film 5 made of a metal thin film material mainly composed of silver or nickel having a high light reflectivity on the exposed surface of the lead frames 1a and 1b, the luminous efficiency is further improved. A high light emitting module can be realized.

  Further, the lead frames 1a and 1b are processed into a taper shape or a curved surface shape (or a parabolic shape or the like), so that the light emitted from the side surface of the LED 8 can be controlled to be reflected in the direction of the arrow 4, and the light emitting module The effect that the brightness of the can be further increased can be exhibited.

  The LED 8 is usually hermetically sealed using a transparent resin or the like that can ensure the reliability of the light emitting element and function as a lens (not shown). As this transparent resin, it is desirable to use PMMA (polymethacrylate) or silicon-based transparent resin. Moreover, when an epoxy resin is used, it is necessary to add a UV inhibitor for preventing yellowing of the epoxy resin. This is because the epoxy resin may be yellowed by light when a white or blue light emitting element is used for the LED 8.

  Moreover, it is desirable to use a soft transparent resin (having a hardness lower than that of an epoxy resin) such as a silicon resin as the transparent resin. By using this flexible resin material, it is possible to prevent stress concentration on the connection portion between the LED 8 and the lead frames 1a and 1b when the LED 8 generates heat and thermally expands.

  Similarly, stress concentration on the gold wire can be reduced when the LED 8 and the lead frames 1a and 1b are connected by wire bonding (the gold wire is difficult to be cut).

  Further, by reducing the thickness of the heat conductive resin 2 that insulates between the lead frames 1a and 1b and the metal substrate 3 as much as possible (and more uniformly), heat diffusion from the lead frames 1a and 1b to the metal substrate 3 is achieved. Increases sex. Thereby, the heat generated in the LED 8 is transferred to the lead frames 1a and 1b. By devising the connection destination of the lead frames 1a and 1b, it is possible to dissipate a considerable amount of heat to the outside through the lead frames 1a and 1b. Since it has a structure that can diffuse to the metal substrate 3 through the conductive resin 2, it is possible to realize a light emitting module that can efficiently diffuse the heat generated by the LED 8 through the metal substrate 3. Since heat is radiated by combining the lead frames 1a and 1b used as the electrodes and the heat radiating plate with the metal substrate 3 for heat radiating as described above, it is possible to mount a plurality of LEDs 8 having high luminance characteristics at high density. The light emitting module which can be realized is realizable.

Moreover, it is desirable to use the thermally conductive resin 2 in which an inorganic filler having excellent thermal conductivity is dispersed in a thermosetting resin. In particular, the inorganic filler is substantially spherical and has a diameter of 0. 0. 1 to 100 μm is appropriate (if it is less than 0.1 μm, it may be difficult to disperse in the resin). Therefore, the filling amount of the inorganic filler in the heat conductive resin 2 is filled at a high concentration of 70 to 95% by weight in order to increase the heat conductivity. In Embodiment 1, the inorganic filler is a mixture of two types of Al ₂ O ₃ having an average particle diameter of 3 μm and an average particle diameter of 12 μm. By using the Al ₂ O ₃ having an average particle size of the large and small two types, it is possible to fill the Al ₂ O ₃ of smaller average particle size in the gap Al ₂ O ₃ of greater average particle size, the Al ₂ O ₃ 90 It can be filled at a high concentration up to nearly% by weight. As a result, the heat conductivity of the heat conductive resin 2 is about 5 W / (m · K). The inorganic filler may contain at least one selected from the group consisting of MgO, BN, SiC, Si ₃ N ₄ and AlN excellent in thermal conductivity instead of Al ₂ O ₃ .

  In addition, as a thermosetting insulating resin, at least 1 type of resin is included among an epoxy resin, a phenol resin, and cyanate resin. These resins are excellent in heat resistance and electrical insulation. If the thickness of the heat conductive resin 2 is reduced, the heat generated from the LEDs 8 attached to the lead frames 1a and 1b can be easily transferred to the metal substrate 3. However, the insulation resistance becomes a problem, and if it is too thick, the thermal resistance increases. What is necessary is just to set to 50-500 micrometers which is the optimal thickness in consideration of a withstand voltage and a thermal resistance, More preferably, it is 50-200 micrometers.

  As described above, the heat generated from the LED 8 is first dissipated by conducting heat laterally from the lead frames 1a and 1b. This is because the lead frames 1a and 1b are made of copper having high thermal conductivity. Next, the heat transferred to the lead frames 1 a and 1 b is conducted to the metal substrate 3 through the heat conductive resin 2. Furthermore, the heat of the metal substrate 3 can be configured to have excellent heat dissipation by devising the connection structure. For example, heat can be efficiently radiated by transmitting to a heat sink or the like.

  The metal substrate 3 is preferably aluminum, copper, or an alloy containing them as a main component, which has good thermal conductivity.

  In this way, the heat generated in the LED 8 can be diffused efficiently and at high speed, so that the LED 8 can be efficiently cooled, and a plurality of LEDs 8 (and LEDs that require high heat dissipation) are contained in the recess 6. Even) can be mounted with high density.

  As a result, a small, low-profile light emitting module capable of high-density mounting can be realized. Such a light emitting module is particularly effective for a backlight of a liquid crystal display device or the like.

  The plurality of LEDs 8 are supplied with current from the plurality of lead frames 1a and are connected to the ground electrode of the lead frame 1b, thereby emitting light in a predetermined color.

  Further, by mounting the LED 8 that emits light of different wavelengths, a light emitting module that covers a desired wide wavelength band can be realized.

  Also, by mounting one lead frame 1b as one common ground electrode, the other lead frame 1a as one common anode electrode, and mounting the light emitting element in parallel on the ground electrode and the anode electrode, In particular, in the lead frame 1a, it is possible to realize a light-emitting module mounted with high density and excellent in thermal conductivity. At this time, it is preferable to select and mount elements that emit light of the same wavelength. This is because the voltage or current applied to the LED 8 needs to be constant.

  The color of the heat conductive resin 2 is preferably white (or colorless near white) from the viewpoint of reflectance. This is because the effect of reflecting from the exposed heat conductive resin 2 can be exhibited. On the other hand, when it is colored black, red, blue or the like, it becomes difficult to reflect the light emitted from the LED 8 and affects the light emission efficiency.

  In this way, a plurality of LEDs 8 are mounted on the bottom surface of the recess 6 so as to straddle the lead frames 1a and 1b, and the lead frames 1a and 1b are further bent into a tapered shape and used as a reflector. It is preferable to form it widely also on the side wall surface, and it is desirable to make it 50 to 95% of the side wall surface. Thereby, the light emitted efficiently can be collected and reflected in a predetermined direction on the front surface.

  In addition, when the area ratio which occupies for the side wall of lead frame 1a, 1b is less than 50%, there exists a possibility of reducing the light reflection amount by the surface of lead frame 1a, 1b. If it exceeds 95% (when the exposed ratio of the heat conductive resin 2 on the side surface is less than 5%), the possibility of short-circuiting between the lead frames 1a or between the lead frames 1a and 1b increases.

  Note that the shape of the recess 6 is desirably a shape that narrows toward the bottom, and a reflector having any shape can be obtained by appropriately bending it into a predetermined shape from the characteristics of the light-emitting element or the light-emitting characteristics required for the backlight. It is possible to realize a light emitting module that can be freely designed with light reflection efficiency.

  Next, the manufacturing method of the light emitting module in this Embodiment 1 is demonstrated using drawing. 3 and 4 are plan views for explaining the method for manufacturing the light emitting module according to Embodiment 1, and FIGS. 5 to 10 are cross-sectional views.

  FIG. 3 is a plan view of the lead frame 1 according to the first embodiment, which is used as a continuous hoop. The lead frame 1a can be singulated, and the lead frame 1b is a continuous metal piece.

  A guide hole 20 is provided to mechanically transport the hoop-shaped lead frame 1. A position where the LED 8 is mounted across the lead frame 1a and the lead frame 1b is indicated by a dotted line.

  A dotted line 30 indicates a position where the lead frame 1 is bent.

  4 shows a state in which the thermally conductive resin 2 and the metal substrate 3 are joined and the LED 8 is mounted, and then punched out to cut off an excess portion of the lead frame 1 as a predetermined light emitting module.

  Next, a manufacturing method for manufacturing a light emitting module will be described in detail.

  5-10 is sectional drawing which shows an example of the manufacturing method of the light emitting module in this Embodiment 1. FIG. In FIG. 5, 10 is a lower mold, 11 is a mold, 12 is an upper mold, and 13 is a dirt prevention film for preventing the lead frame 1 from being stained.

  First, a sheet-like metal plate mainly made of predetermined copper is punched into a predetermined shape using a press or the like, and this is used as the lead frame 1.

  At this time, when the reflective film 5 is formed, a thin film mainly composed of silver or the like is preferably formed on at least one surface of the sheet-like metal plate.

  Next, a lower mold 10 and a mold 11 are set, and a metal substrate 3 made of copper having a main component of 1 mm in thickness processed into a predetermined dimension is placed on the metal mold 3. An uncured sheet-like heat conductive resin 2 is set. At this time, the heat conductive resin 2 is preliminarily kneaded with an inorganic filler having excellent heat conductivity and an epoxy resin, etc. at a predetermined blending ratio, and then made into a sheet shape by a rolling roll or the like so as to have a predetermined thickness. It can be produced by processing into The thickness of the rolled sheet is preferably a thickness that takes into account the amount of the heat conductive resin 2 that fills the gaps in the lead frame 1.

  Then, the lead frame 1 is positioned on the heat conductive resin 2 and set between the mold 11 and the upper mold 12.

  Next, as shown in FIG. 6, the lead frame 1 is pressed against the heat conductive resin 2 while lowering the upper mold 12 by a pressing device (not shown in FIG. 6), and the temperature is set at a predetermined temperature. Heat cure in time. At this time, by setting the antifouling film 13 between the lead frame 1 and the mold 12, when the lead frame 1 is pressed into the heat conductive resin 2, the surface of the lead frame 1 is stained. In addition to preventing, the generation of air residue can be prevented.

  After that, as shown in FIG. 7, the lead frame 1 and the metal substrate 3 are integrated with the heat conductive resin 2 by taking out from the molding die, thereby producing a molded product.

  Next, as shown in FIG. 8, the LED 8 is mounted by bump mounting using a solder bump connection technique or the like so as to straddle the lead frame 1a and the lead frame 1b.

  Thereafter, as shown in FIG. 9, an extra portion of the lead frame 1 that has been required to be handled as a continuous hoop is cut by using a die or the like to be cut into an outer shape of a predetermined light emitting module.

  Then, as shown in FIG. 10, it is bent along a predetermined bending position 14 using a die or the like in a tapered shape. The bent shape can be easily processed into a predetermined shape according to the shape and size of the light emitting module.

  Then, the light emitting module as shown in FIG. 1 is completed by covering with a transparent resin or the like as necessary.

Next, the insulating material will be described in more detail. The thermally conductive resin 2 is composed of a filler and an insulating resin. As this filler, an inorganic filler is desirable. The inorganic filler preferably includes at least one selected from the group consisting of Al ₂ O ₃ , MgO, BN, SiC, Si ₃ N ₄ and AlN having excellent thermal conductivity. If MgO is used, the linear thermal expansion coefficient can be increased, and if BN is used, the linear thermal expansion coefficient can be decreased. In this way, the thermal conductive resin 2 having a thermal conductivity of 1 to 10 W / (m · K) 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. Further, if the thermal conductivity is to be made higher than 10 W / (m · K), it is necessary to increase the amount of inorganic filler, which may affect the workability during pressing.

  The insulating resin is preferably a thermosetting resin, and specifically includes at least one selected from the group consisting of an epoxy resin, a phenol resin, and an isocyanate resin.

In addition, the inorganic filler has a substantially spherical shape and a diameter of 0.1 to 100 μm. The smaller the particle size, the better the filling rate into the resin. Therefore, the filling amount (or content) of the inorganic filler in the heat conductive resin 2 is filled at a high concentration of 70 to 95% by weight in order to increase the heat conductivity. In particular, in the first embodiment, the inorganic filler is a mixture of two types of Al ₂ O ₃ having an average particle diameter of 3 μm and an average particle diameter of 12 μm. 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 heat conductivity of the heat conductive resin 2 is about 5 W / m · K. And when the filling rate of an inorganic filler is less than 70 weight%, thermal conductivity may fall. Further, when the filling rate (or content rate) of the inorganic filler exceeds 95% by weight, the moldability of the uncured thermal conductive resin 2 may be affected. There is a possibility of affecting the adhesiveness (for example, when embedded or attached to the surface).

  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.

  Next, the material of the lead frame 1 will be described. The lead frame 1 is preferably made of copper as a main material. This is because copper has both excellent thermal conductivity and electrical conductivity. In order to improve the workability and thermal conductivity as the lead frame 1, the copper material used as the lead frame 1 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 made of at least one kind of 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 in the range of 0.1 to 0.15 wt%, the softening temperature can be increased to 400 ° C. For comparison, the lead frame 1 was manufactured using Sn-free copper (Cu> 99.96 wt%). The electrical conductivity was low, but in the completed heat dissipation substrate, particularly, the formation portion of the recess 6 was distorted. It may occur. As a result of detailed examination, the softening point of the material is as low as about 200 ° C., so the reliability after mounting the LED 8 (repetition of heat generation / cooling, etc.) when mounting the component in the subsequent process (soldering) It was predicted that there was a possibility of deformation.

  On the other hand, when a copper material with Cu + Sn> 99.96 wt% was used, it was not particularly affected by the heat generated by various mounted components and the plurality of LEDs 8. And 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 to be added to copper, a range of 0.015 to 0.15 wt% is desirable. When the addition amount is lower 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, a composition range of 0.1 to 5 wt% for Ni, 0.01 to 2 wt% for Si, 0.1 to 5 wt% for Zn, and 0.005 to 0.1 wt% for P is desirable.

  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 raise effect of a softening point 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 to 5 wt% and in the case of Cr 0.05 to 1 wt% are desirable. These elements are the same as those described above.

The tensile strength of the copper alloy 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 1 may be affected. In addition, such a material having high tensile strength tends to increase its electrical resistance, and thus may not be suitable for high current applications such as the LED 8 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 1 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, the occurrence of rebound by reaction force) can be suppressed, and the formation accuracy of the recess 6 can be improved. Thus, as the lead frame material, high conductivity is realized by making the lead frame 1 mainly composed of Cu, softening improves workability, and furthermore, it has excellent thermal conductivity, so that the heat dissipation effect. Can also be enhanced.

  A solder layer is previously applied to the surface of the lead frame 1 exposed from the heat conductive resin 2 (the LED 8 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 mountability of components on the lead frame 1 having a large heat capacity and difficult to solder compared to a glass epoxy substrate or the like, and to prevent rusting of the wiring. It is desirable that no solder layer be formed on the surface (or embedded surface) of the lead frame 1 that is in contact with the heat conductive resin 2. When a solder layer or a tin layer is formed on the surface in contact with the heat conductive resin 2 in this way, this layer becomes soft during soldering, which affects the adhesion (or bond strength) between the lead frame 1 and the heat conductive resin 2. May give. 1 and 2, the solder layer and the tin layer are not shown.

  The metal substrate 3 is made of aluminum, copper, or an alloy containing them as a main component, which has good thermal conductivity. In particular, in the first embodiment, the thickness of the metal substrate 3 is 1 mm, but the thickness can be designed according to the specifications of the light emitting module or the like (when the thickness of the metal substrate 3 is less than 0.1 mm, heat dissipation and strength In addition, if the thickness of the metal substrate 3 exceeds 5 mm, it is disadvantageous in terms of thickness and weight). The metal substrate 3 is not only a plate-shaped substrate, but also fins (or uneven portions) are formed on the opposite surface joined to the heat conductive resin 2 to increase the surface area in order to further improve heat dissipation. In addition, the heat dissipation can be enhanced.

By setting the total expansion coefficient to 8 to 20 × 10 ⁻⁶ / ° C., it is possible to reduce the warpage and distortion of the entire substrate of the light emitting module by bringing it closer to the linear expansion coefficient of the metal substrate 3 and the LED 8. In addition, when the mounting components are surface-mounted, it is important in terms of reliability to match the thermal expansion coefficients with each other.

  It is also possible to process the metal substrate 3 so that it can be screwed to another heat radiating plate (not shown).

  Further, as the lead frame 1, at least a part of which is punched into a three-dimensional recess shape in advance can be used. The thickness of the lead frame 1 is desirably 0.1 to 1.0 mm (more desirably 0.4 to 0.8 mm). This is because a large current (for example, 30 to 150 A, which may be further increased depending on the number of LEDs to be driven) is required to control the LEDs. Further, if the thickness of the lead frame 1 exceeds 1 mm, pattern miniaturization may be affected when punching with a press.

(Embodiment 2)
Hereinafter, a backlight device according to Embodiment 2 of the present invention will be described with reference to the drawings.

  FIG. 11 is a cross-sectional view showing a configuration of an edge light which is an example of a backlight device according to Embodiment 2 of the present invention.

  The edge light shown in FIG. 11 shows an edge light used for a backlight for a liquid crystal that is required to be thin using a light emitting element such as an LED, and its configuration is LED 8, lead frames 41a and 41b, heat conduction. The light emitted from the light emitting module, which is a light source, is incident from the side surface of the light guide plate 42. The light emitting module is composed of the light emitting resin 2 and the metal substrate 3, the light guide plate 42, the diffusion plate 43, the reflection plate 44, and the frame 45. After the light is guided in a planar shape using the light guide plate 42, the thin planar light source is realized by diffusing the light while controlling the uniformity and directivity using the diffusion plate 43. is there. The reflecting plate 44 is used to make a planar light source that efficiently emits light in one direction by reflecting light emitted from the light guide plate 42. The diffusion plate 43 and the reflection plate 44 can be used as necessary. In addition, a prism or the like can be used to improve the optical characteristics of the edge light. In addition, description of the optical control circuit part etc. which perform optical control of the brightness | luminance of the some LED element mounted, color gamut, color tone, etc. here is abbreviate | omitted.

  In the configuration of the edge light in the second embodiment, the most characteristic point is that the lead frame 41 is bent and used as a reflector, and one end of the lead frame 41a is joined to the edge light frame 45, for example. It is that. At this time, the light of the LED 8 can be efficiently concentrated on the light guide plate 42 by forming the reflection film 5 on the surfaces of the lead frames 41a and 41b. In general, the edge light is arranged by arranging light emitting elements in a row on a thin rod-shaped substrate. In order to realize a thin edge light, heat from the light emitting elements is dissipated. The configuration of the edge light that can efficiently dissipate heat is very important. With the configuration as shown in FIG. 11, the heat generated from the LED 8 is dissipated to the lead frames 41a and 41b, and then from the lead frame 41a. Heat is radiated to the frame 45. And, it is effective from the viewpoint of heat dissipation that the one end of the lead frame 41a and the frame 45 are joined with a larger joining length along the rod-like length direction.

  At this time, the frame 45 is a structural material for reinforcement by using a material having excellent thermal conductivity such as a metal and can have a structure having a large heat radiation area on the back side of the display device, etc. Heat generated from the LED 8 can be efficiently radiated. It is also possible to add a further cooling structure such as a heat radiating fin or a heat pipe to the frame 45.

  The lead frame 41a joined to the frame 45 is preferably on the ground terminal side.

  In addition, when the frame 45 cannot be used as a ground electrode, it is preferable that the lead frame 41 a is joined to the frame 45 after insulating treatment via the heat conductive resin 2. This makes it possible to realize an edge light capable of radiating heat in a state of being electrically insulated, although the heat radiation performance is slightly lower than that of direct bonding. In this case, it is preferable that the other lead frame 41 b is also bonded to the frame 45 after being insulated through the heat conductive resin 2. Thereby, heat dissipation can be improved more.

  Furthermore, by joining the metal substrate 3 to the frame 45, heat dissipation can be further improved. As a result, heat is radiated from the lead frames 41 a and 41 b to the heat conductive resin 2 and then to the metal substrate 3. And since this metal substrate 3 uses the metal material excellent in heat conductivity, it can thermally radiate to the flame | frame 45 efficiently. Further, it is effective against stress such as deflection when the metal substrate 3 is joined to a part of the frame 45 through the heat conductive resin 2 to improve heat dissipation and a very thin edge light is realized. Edge light can be realized.

As described above, by using the light emitting module according to the present invention and the backlight device using the light emitting module , high heat dissipation and downsizing can be realized. Therefore, high luminance can be achieved by mounting a large number of light emitting elements at high density. It is useful as a light source for backlights, projectors, etc. of small and low-profile liquid crystal TVs.

The perspective view of the light emitting module in Embodiment 1 of this invention Cross section A plan view of a lead frame for explaining the manufacturing method Plan view Sectional drawing for demonstrating the manufacturing method Cross section Cross section Cross section Cross section Cross section Sectional drawing of the backlight apparatus in Embodiment 2 of this invention Sectional view of a conventional light emitting module

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Lead frame 2 Thermal conductive resin 3 Metal substrate 4 Arrow which shows the direction of light 5 Reflective film 6 Recessed part 8 LED
9 Bump 10 Lower mold 11 Mold 12 Upper mold 13 Antifouling film 14 Bending position 20 Guide hole 30 Bending position 41a, 41b Lead frame 42 Light guide plate 43 Diffuser plate 44 Reflector plate 45 Frame

Claims (6)

A metal substrate, a thermally conductive resin made of an inorganic filler and a thermosetting resin provided on the metal substrate, and a common ground electrode made of a single conductor provided on the thermally conductive resin A plurality of anode electrode side lead frames made of a conductor independent of the side lead frame, and a plurality of light emitting elements connected to the ground electrode side lead frame and the anode electrode side lead frame. A ground electrode portion that is in surface contact with the heat conductive resin, and a ground side reflective electrode portion that is bent from the ground electrode portion and is not in contact with the heat conductive resin; Has an anode electrode portion that is in surface contact with the thermally conductive resin, and an anode-side reflective electrode portion that is bent from the anode electrode portion and is not in contact with the thermally conductive resin . Yo Wherein the thermally conductive resin is positioned between the metal substrate and the anode electrode unit, after it as its thickness uniform, the light emitting element was connected to said anode electrode portion and the ground electrode section Light emitting module. A metal substrate, a thermally conductive resin made of an inorganic filler and a thermosetting resin provided on the metal substrate, and a common ground electrode made of a single conductor provided on the thermally conductive resin A plurality of anode electrode side lead frames made of a conductor independent of the side lead frame, and a plurality of light emitting elements connected to the ground electrode side lead frame and the anode electrode side lead frame. A ground electrode portion that is in surface contact with the heat conductive resin, and a ground side reflective electrode portion that is bent from the ground electrode portion and is not in contact with the heat conductive resin; Has an anode electrode portion in surface contact with the thermal conductive resin, and an anode-side reflective electrode portion bent from the anode electrode portion and brought into non-contact with the thermal conductive resin. The frame has a uniform width dimension in the extending direction from the ground electrode portion to the ground-side reflective electrode portion, and the anode electrode-side lead frame extends in the extending direction from the anode electrode portion to the anode-side reflective electrode portion. The light emitting module has a uniform width dimension, and the light emitting element is connected to the ground electrode portion and the anode electrode portion. The light emitting module according to claim 1 or 2, wherein a cross-sectional shape of the ground side reflection electrode portion and the anode side reflection electrode portion is tapered or curved. The light emitting module according to claim 1 or 2, wherein a reflective film is provided on the exposed surfaces of the ground electrode side lead frame and the anode electrode side lead frame. A metal substrate, a thermally conductive resin made of an inorganic filler and a thermosetting resin provided on the metal substrate, and a common ground electrode made of a single conductor provided on the thermally conductive resin A plurality of anode electrode side lead frames made of a conductor independent of the side lead frame, and a plurality of light emitting elements connected to the ground electrode side lead frame and the anode electrode side lead frame. A ground electrode portion that is in surface contact with the heat conductive resin, and a ground side reflective electrode portion that is bent from the ground electrode portion and is not in contact with the heat conductive resin; Has an anode electrode portion that is in surface contact with the thermally conductive resin, and an anode-side reflective electrode portion that is bent from the anode electrode portion and is not in contact with the thermally conductive resin. Yo The heat conductive resin positioned between the anode electrode part and the metal substrate was made uniform in thickness, and the light emitting element was connected to the ground electrode part and the anode electrode part. A light-emitting module; a light guide plate that irradiates light of the light-emitting module incident from an incident surface of the side surface; and a frame that covers a part of the light guide plate, and at least the ground-side reflective electrode portion or the anode-side reflective electrode A backlight device having one end joined to a part of the frame. A metal substrate, a thermally conductive resin made of an inorganic filler and a thermosetting resin provided on the metal substrate, and a common ground electrode made of a single conductor provided on the thermally conductive resin A plurality of anode electrode side lead frames made of a conductor independent of the side lead frame, and a plurality of light emitting elements connected to the ground electrode side lead frame and the anode electrode side lead frame. A ground electrode portion that is in surface contact with the heat conductive resin, and a ground side reflective electrode portion that is bent from the ground electrode portion and is not in contact with the heat conductive resin; Has an anode electrode portion in surface contact with the thermal conductive resin, and an anode-side reflective electrode portion bent from the anode electrode portion and brought into non-contact with the thermal conductive resin. The frame has a uniform width dimension in the extending direction from the ground electrode portion to the ground-side reflective electrode portion, and the anode electrode-side lead frame extends in the extending direction from the anode electrode portion to the anode-side reflective electrode portion. A light emitting module connected to the ground electrode portion and the anode electrode portion, a light guide plate that irradiates light of the light emitting module incident from a light incident surface; And a frame that covers a part of the light guide plate, and at least one end of the ground-side reflection electrode part or the anode-side reflection electrode part is joined to a part of the frame.

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