JP2007194610A - Light emitting module, method for fabrication thereof, and indicator using the light emitting module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that brightness and luminous efficiency are lowered by heat generation in light emitting devices owing to shadow influences among light emitting devices, which is increased as the mounting density of the light emitting elements increases. <P>SOLUTION: Plural light emitting devices 104 are slanted to prevent their sides from facing each other so that radiation light from the sides of other light emitting devices 104 can be used effectively. In addition, these devices 104 are mounted on a lead frame 100 so that the side of the lead frame 100 can be used as a reflecting plate for radiation light of the light emitting devices 104; and the lead frame 100 including this side can be used for heat dissipation and current supply, in order to release the heat generated in the light emitting devices 104 to the metal plate 108 of the rear through a heat dissipation resin layer 106 as well as the lead frame 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting module used for a backlight of a display device having a backlight such as a liquid crystal television, a manufacturing method thereof, and a display 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. 13 is a cross-sectional view illustrating an example of a light emitting module. In FIG. 13, 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. 13, 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 light emitting modules are used as backlights for liquid crystals and the like. However, since the ceramic substrate 1 is difficult to process and expensive, there has been a demand for a heat dissipation substrate that is less expensive and has excellent workability.

  On the other hand, the display device side including the liquid crystal TV is desired to expand the color display range. In response to such needs, white LEDs and the like have limitations, and in recent years, red (red), green (green), and blue (blue) single-color light emitting elements, and further purple, orange, red purple, cobalt Attempts have been made to expand the color display range (specifically, the CIE color system, etc.) by adding a special color light emitting element that emits a special color such as blue.

  When such a light emitting module as shown in FIG. 13 is used for such needs, while mounting each of these light emitting elements one by one in the concave portion of the ceramic substrate 1, a uniform color mixture (mixed white color) is produced as a whole. It is necessary to adjust the color balance (for example, white balance described later). On the other hand, it is known that the luminous efficiency of solid light emitting devices such as LEDs decreases as the temperature rises. Furthermore, the degree of decrease in luminous efficiency with respect to temperature varies depending on the emission color of the LED. For these reasons, for example, immediately after the liquid crystal TV is turned on (operated), the LED portion is at room temperature (for example, 25 ° C.). (→ 50 ° C. → 60 ° C.), for example, a phenomenon such as a decrease in red light emission efficiency may occur, and the color reproducibility and the brightness of the backlight may also change.

  On the other hand, as shown in FIG. 13, when the ceramic substrates 1 on which the light emitting elements 2 such as LEDs are mounted one by one are arranged on the heat radiating plate 3, it is advantageous from the aspect of heat dissipation, while a filter or diffusion is used. It becomes difficult to produce a white color by mixing light using a plate or the like (or to produce a white color having high color rendering properties by mixing RGB + special colors).

Therefore, there are a large number of light-emitting elements that can cope with higher luminance of the light-emitting elements (in this case, it is necessary to pass a large current) and multi-LEDs (multiple LEDs are mounted at a high density). There is a demand for a light-emitting module that can be mounted at high density and has high workability and excellent heat dissipation.
JP 2004-311791 A

  However, in the conventional configuration, since the heat dissipation substrate on which the light emitting element 2 is mounted is the ceramic substrate 1, there is a problem that it is disadvantageous in terms of workability and cost.

  The present invention solves the above-described conventional problems, and uses a metal lead frame, a sheet-like heat radiation resin layer, and a metal plate instead of a ceramic substrate, thereby producing a light-emitting module with good processability and its manufacture. It is an object to provide a method and a display device using the method.

  In order to solve the above-described problems, the present invention provides at least a sheet-like heat dissipation resin layer, a lead frame partially embedded in the first surface of the heat dissipation resin layer, and the second surface of the heat dissipation resin layer. A plurality of light emitting elements mounted on the lead frame such that their side surfaces do not face each other.

  In this way, a light emitting element such as an LED is directly mounted on a lead frame having high heat dissipation, and the heat of the lead frame is further transmitted to a metal plate for heat dissipation formed on the back surface through a heat dissipation resin layer having high heat dissipation. Thus, the light emitting element can be efficiently cooled. Furthermore, the light emission efficiency as a light emitting module is improved by effectively using the light emission from the side surface of the light emitting element mounted on the lead frame.

  The light emitting module obtained by the light emitting module of the present invention and the manufacturing method thereof can efficiently diffuse the heat generated by the light emitting elements such as LEDs and semiconductor lasers, and can effectively cool the light emitting elements such as LEDs.

(Embodiment 1)
Hereinafter, the light emitting module according to Embodiment 1 of the present invention will be described.

  1A and 1B are a top view and a cross-sectional view illustrating a light-emitting module according to Embodiment 1, in which FIG. 1A is a top view and FIG. 1B is a cross-sectional view taken along an arrow 110a in FIG. . In FIG. 1, 100a and 100b are lead frames, 102 is a dotted line indicating the bending position of the lead frames 100a and 100b, 104 is a light emitting element such as an LED, 106 is a sheet-like heat radiation resin layer, 108 is a metal plate, 110a and 110b Is an arrow. An arrow 110a indicates a cross-sectional portion of FIG. 112 is a light emitting module, and 114 is a resin. 116a and 116b are auxiliary lines.

  First, description will be made with reference to FIG. In FIG. 1A, a plurality of light-emitting elements 104 are mounted in the recesses of the light-emitting module 112 in a state in which the light-emitting elements 104 are arranged obliquely with respect to each other. Note that the concave portion in FIG. 1A corresponds to a bent portion indicated by a dotted line 102. The plurality of light emitting elements 104 are mounted on the lead frame 100a, and a plurality of lead frames 100b are also formed near the lead frame 100a. The plurality of light emitting elements 104 are supplied with current from the lead frame 100a and the lead frame 100b and emit light in a predetermined color. 1A and 1B, a connection portion between the light emitting element 104 and the lead frame 100a and a connection portion between the light emitting element 104 and the lead frame 100b (for example, connection by a wire bonder) are not shown. The lead frames 100 a and 100 b are formed in a state of being embedded in the heat-dissipating resin layer 106 and constitute the light emitting module 112.

  Next, with reference to FIG. 1B, the concave portion, which is a portion where the light emitting element 104 is mounted, will be described. In FIG. 1B, the lead frames 100a and 100b are formed in a mortar-shaped depression together with the heat-dissipating resin layer 106. The light emitting element 104 is mounted on the lead frames 100a and 100b at the bottom of the mortar shape. The surface of the light emitting element 104 is covered and protected by the resin 114.

In FIG. 1B, it is desirable to use a heat dissipation resin layer 106 in which a highly heat dissipating inorganic filler is dispersed in a curable resin. 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 heat radiation resin layer 106. Therefore, the filling amount of the inorganic filler in the heat radiation resin layer 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 radiation resin layer 106 is about 5 W / (m · K). Note that the thermosetting insulating resin constituting a part of the heat radiation resin layer 106 includes 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 dissipation resin layer 106 is reduced, heat generated in the light emitting element 104 attached to the lead frame 100a can be easily transferred to the metal plate 108. If the thickness is too large, the thermal resistance increases, and therefore, an optimum thickness may be set in consideration of the withstand voltage and the thermal resistance.

  The color of the heat radiation resin layer 106 is desirably white (or colorless near 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 104, and the light emission efficiency is lowered.

  Further, as shown in FIG. 1B, the mounting portion of the light emitting element 104 is preferably formed in a recess formed by the lead frames 100a and 100b. By forming the light-emitting element 104 at the bottom of the recess, the heat radiated from the side surfaces of the light-emitting element 104 is exposed to heat between the lead frames 100a and 100b or the lead frames 100a and 100b serving as the wall surfaces of the recess. The resin layer 106 can be effectively reflected in a predetermined direction, and the light emission efficiency can be increased. Further, when the light-emitting element 104 is covered with a resin 114 (for example, a transparent resin or a resin containing a fluorescent material), the resin 114 does not spill, so that the injection becomes easy.

  As described above, the plurality of light emitting elements 104 are mounted on the lead frames 100a and 100b at the bottom surface of the recess, and the lead frame is also formed widely on the sidewall surface of the recess (desirably 50% or more and 95% or less of the sidewall surface). ) In addition, when the area ratio which occupies for the side wall of lead frame 100a, 100b is less than 50%, it may affect to reduce the heat conduction by a lead frame, and may reduce the light reflection amount by the lead frame 100a, 100b surface. Further, when it exceeds 95% (that is, when the exposed ratio of the heat radiation resin layer 106 on the side surface is less than 5%), that is, when the interval between the lead frames 100a and 100b is narrowed, the possibility of short-circuiting is increased. The metal plate 108 is preferably made of aluminum, copper, or an alloy containing them as a main component, which has good thermal conductivity.

  Note that in FIG. 1A, the auxiliary line 116a is a center line of the recess, and the light-emitting element 104 is preferably mounted over the auxiliary line 116a which is the center line. In addition, the first lead frame 100a on which the plurality of light emitting elements 104 are mounted is desirably formed with a large area including the center line 116a. Further, in FIG. 1A, the distance between the auxiliary lines 116a and 116b (illustrated by an arrow 110b) indicates that the first lead frame 100a extends beyond the center of the recess. As described above, it is desirable that the first lead frame 100a occupies an area of 50% or more and 95% or less of the side surface (or bottom surface) forming the recess. Thus, by forming the first lead frame 100a wider, the heat dissipation effect is enhanced and the reflection efficiency is also enhanced.

(Embodiment 2)
Hereinafter, an example of the manufacturing method of the light emitting module 112 in Embodiment 2 of this invention is demonstrated.

  2 and 3 are cross-sectional views showing an example of a method for manufacturing the light emitting module 112 in the second embodiment. In FIG. 2, 118a and 118b are dies, 120 is a burr, and 122 is an antifouling film. First, the metal plate 108 is punched into a predetermined shape using press working or the like, and these are used as lead frames 100a and 100b. Next, the heat radiation resin layer 106 and the metal plate 108 are set under the lead frames 100a and 100b. Then, with these members positioned, they are set between the molds 118a and 118b. Next, the lead frames 100a and 100b are pressed against the heat-dissipating resin layer 106 by moving the dies 118a and 118b in the direction of the arrow 110a by a press device (not shown in FIG. 2). Further, as shown in FIG. 2, it is desirable to set a stain prevention film 122 between the lead frames 100a and 100b and the mold 118a. Further, it is desirable that the antifouling film 122 is a film having a certain degree of air permeability such as a nonwoven fabric. In this way, when the lead frames 100a and 100b are pressed into the heat radiation resin layer 106 using the molds 118a and 118b, the air can be easily removed as indicated by the arrow 110b (through the antifouling film 122). Thus, air can be prevented from being generated at the interface between the lead frames 100a and 100b and the heat radiating resin layer 106 or at the interface between the metal plate 108 and the heat radiating resin layer 106.

  It should be noted that when the lead frames 100a and 100b are pulled out into a predetermined shape with a mold, it is desirable that the direction of the burr 120 generated at the end of the lead frames 100a and 100b be on the dirt prevention film 122 side. In this way, when the lead frames 100a and 100b are pressed, the burr 120 bites into the antifouling film 122, so that the heat radiation resin layer is formed on the surface of the lead frames 100a and 100b (for example, the mounting surface of the light emitting element 104). 106 can be prevented from wrapping around.

  FIG. 3 is a cross-sectional view after the press working is completed. As shown in FIG. 3, the light emitting module 112 is completed by moving the molds 118a and 118b in the direction of the arrow 110a (note that the light emitting element 104 and the like are not yet mounted in the state of FIG. 3). Then, the light emitting element 104 is mounted on the light emitting module 112 of FIG. 3 and further covered with a resin 114, whereby the light emitting module 112 as shown in FIG. 1 is completed.

  Then, the lead frames 100a and 100b processed into a predetermined shape, the heat-dissipating resin layer 106 including the heat conductive resin, and the metal plate 108 are integrated to form a heat-dissipating substrate. When the mold is formed, the anti-stain film 122 is sandwiched between the surfaces of the lead frames 100a and 100b and the molds 118a and 118b (further, press is not shown) so that the mold 118a, 118b and the press are prevented from being stained.

  Thus, at least the sheet-like heat radiation resin layer 106, the lead frames 100a and 100b partially embedded in the first surface of the heat radiation resin layer 106, and the second surface of the heat radiation resin layer 106 were provided. A substrate made of the metal plate 108 is created. Here, it is desirable that at least a part of the lead frames 100a and 100b is embedded in the heat dissipation resin layer 106. Furthermore, it is desirable that the surfaces of the lead frames 100a and 100b and the surface of the heat-dissipating resin layer 106 be substantially flush with each other. By doing so, no step is generated between the lead frames 100a and 100b and the heat radiation resin layer 106, so that it is easy to form a solder resist (not shown) formed thereon.

Next, the heat dissipation resin layer 106 will be described in more detail. The heat radiation resin layer 106 is composed of a filler and a resin. The filler is preferably an inorganic filler. As the inorganic filler, it is desirable to have one containing at least one selected from the group consisting of Al ₂ O ₃ , MgO, BN, SiO ₂ , SiC, Si ₃ N ₄ , and AlN. In addition, when an inorganic filler is used, heat dissipation can be improved. However, when MgO is used 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.

  The thermal conductivity of the heat radiation resin layer 106 is preferably 1 W / (m · K) or more and 30 W / (m · K) or less. Below 1 W / (m · K), no heat dissipation effect is obtained. In addition, in order to make it larger than 30 W / (m · K), it is necessary to select a very expensive material.

  The resin used for the heat radiation resin layer 106 is desirably 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. These resins are excellent in reliability and heat resistance.

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 heat radiation resin layer 106. Therefore, the filling amount (or content rate) of the inorganic filler in the heat radiation resin layer 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 radiation resin layer 106 is about 5 W / (m · K). In addition, when the filling rate of a filler is less than 70 weight%, thermal conductivity may fall. Further, if the filling rate (or content) of the filler exceeds 95% by weight, the moldability of the heat dissipation resin layer 106 before curing may be reduced, and the heat dissipation resin layer 106 and the lead frames 100a and 100b are bonded. This may have an effect of lowering the property (for example, embedded or attached to the surface thereof), and may affect the fine wiring portion formed in the thin-walled portion.

  The thermosetting heat radiation resin layer 106 includes at least one kind of resin among epoxy resin, phenol resin, and cyanate resin. These resins are excellent in heat resistance and electrical insulation. Note that if the thickness of the insulator made of the heat-dissipating resin layer 106 is reduced, heat generated in the light-emitting element 104 attached to the lead frames 100a and 100b can be easily transferred to the metal plate 108. On the other hand, if the thickness of the insulator is too thick, the thermal resistance increases. Therefore, the optimal thickness may be set in consideration of the characteristics of the withstand voltage and the thermal resistance based on these facts.

  Next, the material of the lead frames 100a and 100b will be described. As a material of the lead frame 100, a material mainly composed of copper is desirable. This is because copper has both excellent thermal conductivity and conductivity characteristics.

  As a material for the lead frame 100, it is desirable to select tough pitch copper. This is because tough pitch copper (TCP, Tow-Pitch Copper) is easy to process and has excellent thermal conductivity. Note that tough pitch copper is a material used for conduction with a purity of about 99.5%, and has low electrical resistance and excellent thermal conductivity.

  Further, an oxygen-free cylinder can be used as the material of the lead frame 100 depending on the application. This is because oxygen-free copper is excellent in thermal conductivity and conductivity. Oxygen-free copper (OFC, Oxygen-Fee Copper) is copper having a purity of about 99.995% that does not contain oxides.

  The material of the lead frame 100 can be selected from a copper alloy (or a metal mainly composed of copper). In this case, it is desirable to add additives other than copper to the copper material used as the lead frames 100a and 100b. For example, an alloy mainly composed of Cu + Sn copper can be used. In the case of Sn, 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 lead frames 100a and 100b were made using Sn-free copper (Cu> 99.96 wt%), the electrical conductivity was low, but distortion was generated particularly in the recessed portion formation portion in the completed heat dissipation substrate. There was a case. As a result of detailed examination, the softening point of the material is as low as about 200 ° C. Therefore, the quality for the subsequent component mounting (soldering) and the reliability evaluation after LED mounting (heating / cooling repeated, etc.) It was predicted that there was a possibility of deformation. On the other hand, when a copper material (copper alloy) 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. Moreover, when there are more addition amounts than 0.15 wt%, it may have the influence which reduces an electrical property. 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 individually or in combination 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 it is more than the ratio described here, there is a possibility of causing an effect of lowering the 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 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 frames 100a and 100b may be affected. Further, such a material having a high tensile strength tends to increase its electrical resistance, and thus may not be suitable for high current applications such as LEDs used in the first embodiment. On the other hand, the tensile strength is 600 N / mm ² or less (if the lead frames 100a and 100b require fine and complicated processing, preferably 400 N / mm ² or less, and further low tensile strength that does not cause springback is desirable. ) Is suitable for high current applications such as LEDs used in Embodiment 1 because of high Cu content and low electrical conductivity. Further, since this material is soft and excellent in workability, it is suitable for high current applications such as LEDs used in the first embodiment.

  Note that the thickness of the lead frame 100 is desirably 0.10 mm or more and 1.0 mm or less, and at least a part of the lead frame 100 is punched (or processed) into a three-dimensional recess shape, so that the side surface of the lead frame 100 (or The wall surface of the concave portion can be a reflecting surface. Further, by using the lead frame 100 as a wiring, a large current of several A to several tens of A can be passed. If the thickness of the lead frame 100 is less than 0.10 mm, the lead frame 100 is easily deformed, and thus it may be difficult to process the concave shape. On the other hand, if the thickness exceeds 1.0 mm, it may be difficult to miniaturize the pattern of the lead frame 100 (or to punch it into a miniaturized pattern).

  It should be noted that solderability is improved in advance on the surfaces of the lead frames 100a and 100b exposed from the heat-dissipating resin layer 106 (the light-emitting element 104 or a mounting surface of a control IC or chip component (not shown)). By forming a solder layer or a tin layer on the lead frame 100a, 100b, which has a larger heat capacity than a glass epoxy substrate (glass epoxy substrate) or the like and is difficult to solder, component mounting is improved. Rust prevention is possible. It is desirable that no solder layer be formed on the surface (or embedded surface) of the lead frames 100a and 100b that is in contact with the heat-dissipating resin layer 106. When a solder layer or a tin layer is formed on the surface in contact with the heat radiating resin layer 106 in this manner, this layer becomes soft during soldering, and the adhesiveness (or bond strength) between the lead frames 100a and 100b and the heat radiating resin layer 106 is reduced. May have an effect. 1 and 2, the solder layer and the tin layer are not shown.

The metal plate 108 is made of aluminum, copper, or an alloy containing them as a main component, which has good thermal conductivity. In particular, in the present embodiment, the thickness of the metal plate 108 is 1 mm. Further, the metal plate 108 is not limited to a simple plate shape, and a fin portion may be formed on the surface opposite to the surface on which the insulator is laminated in order to increase the surface area in order to further improve heat dissipation. good. The linear expansion coefficient is set to 8 × 10 ⁻⁶ / ° C. to 20 × 10 ⁻⁶ / ° C. By making the linear expansion coefficient close to the linear expansion coefficient of the light emitting element 104 such as the metal plate 108 or LED, warpage and distortion of the entire substrate can be reduced. . Also, when these components are surface-mounted, matching the thermal expansion coefficients with each other is important from the viewpoint of improving reliability. Needless to say, the metal plate 108 can be screwed to another heat radiating plate (not shown), and heat can be diffused through the heat radiating plate to improve heat dissipation.

  For example, when an attempt is made to produce the shape shown in FIG. 1 or the like with the lead frame 100, such wiring is a simple shape (punched into a rectangle and simply bent according to the inclination of the recess), so that a general lead frame 100 is used. There is a high possibility that it can be handled with materials. However, like the lead frame 100 in FIG. 1 (A), the concave wall (three-dimensional shape) is punched at the same time, and at the same time, the concave wall surface is a complicated mortar type (or a curved shape as in FIG. And the curvature of the lower part of the recess are different from each other). In addition, it is necessary to have a high degree of molding capable of aligning the plurality of light emitting elements 104 at an optically high accuracy level in the recess (for example, about 2 mm to 5 mm in width). In order to reduce costs, it is necessary to press work and speed up the heat-dissipating resin layer 106. Springback in such a process (even if it is bent to the required angle, it will be repelled by the reaction force if the pressure is removed. ) Must also be suppressed. From this point of view, it is necessary to use a metal member having excellent workability as described in the second embodiment.

(Embodiment 3)
Hereinafter, the light emitting module 112 according to Embodiment 3 of the present invention will be described with reference to FIGS.

  Next, how to arrange the light emitting elements 104 in the light emitting module 112 will be described with reference to FIG. FIG. 4 is a perspective view illustrating a state in which a plurality of light emitting elements are arranged in the recess. FIG. 4A corresponds to a conventional arrangement of the light emitting elements 104. For example, a plurality of light emitting elements 104 are regularly arranged so that adjacent sides are parallel (hereinafter referred to as square alignment). . In FIG. 4, auxiliary lines 116 indicate that the plurality of light emitting elements 104 are on the bottom surface of the recess, and the lead frames 100a and 100b, the heat radiation resin layer 106, the metal plate 108, and the like are not shown.

  FIG. 4B is an example of how to arrange the light emitting elements 104 to effectively use the emitted light from the side surfaces, and a plurality of light emitting elements 104 are arranged in a row so that the side surfaces do not face each other. A state is shown (hereinafter referred to as a diagonal line). In addition, an arrow 110 in FIGS. 4A and 4B indicates a state in which light emitted from the light-emitting element 104 is reflected by the wall surface of the recess.

  Next, the problem of the arrangement of the light emitting elements 104 (the conventional square arrangement) will be described. FIG. 5 is a top view for explaining the problem of the square arrangement. In FIG. 5, a plurality of light emitting elements 104a, 104b, 104c, and 104d are arranged in a line with adjacent sides parallel to each other. Arrows 110a and 110b mean light emitted from the light emitting elements 104a, 104b, 104c, and 104d, respectively.

  As shown in FIG. 5A, when a plurality of light emitting elements 104a, 104b, 104c, and 104d are arranged in a line, the light emitting elements 104a and 104d at both ends are effectively shown by arrows 110e on the three surfaces. The light can be radiated effectively, and this light is reflected by the side surface of the concave portion (the concave portion is not shown in FIG. 5), and the light emitting module 112 is lit. On the other hand, the light radiated to the side indicated by the arrow 110f hits the other light emitting elements 104a to 104d, and thus is not very useful for making the light emitting module 112 shine. As a result, for example, even if the light emitting element 104a emits red, the light emitting element 104b is blue, the light emitting element 104c is green, and the light emitting element 104d is a special color such as purple, they interfere with each other. As for the light output from, it becomes unbalanced.

  FIG. 5B illustrates a plurality of light-emitting elements 104 that are squarely arranged in the XY directions. From FIG. 5B, it can be seen that when the rectangular array is used, the side light from the light emitting element 104 mounted inside does not easily reach the outside (or the side surface of the recess) as indicated by an arrow 110f.

  FIG. 6 is a perspective view when a plurality of light emitting elements are mounted in an oblique line. As shown in FIGS. 6A and 6B, the light-emitting elements 104 are arranged on the bottom of the recesses, in a diagonal line (the corners of the light-emitting elements 104 are adjacent to each other, or a plurality of light-emitting elements are side-by-side. By mounting so as not to face each other), the radiated light (arrow 110) from the side surface of the light emitting element 104 is irradiated to the side surface of the recess without being shaded by the other light emitting elements 104, and the luminance of the light emitting module 112 is increased. Enhanced. 6A and 6B is the interval between the light emitting elements 104. In FIG. 6B, the plurality of light emitting elements 104 are arranged at a certain distance from each other. By arranging as shown in FIG. 6B, the heat dissipation effect of the light-emitting element 104 is also enhanced, so that even the light-emitting element 104 that emits light in different colors can be hardly affected by white balance due to temperature rise.

(Embodiment 4)
In Embodiment 4, the shape of the side surface of the recess that functions as a reflection mirror of the light emitting module 112 will be described with reference to FIG. 7A is a top view of the light emitting module 112 according to Embodiment 4, FIG. 7B is a cross-sectional view taken along the arrow 110 in FIG. 7A, and the case of Embodiment 4 is shown in FIG. 7B. It can be seen that the side surface of the recess is formed with a curvature as indicated by the auxiliary line 116a. Thus, the luminous efficiency can be further increased by forming the side surface of the recess as round (or parabola, etc.) as indicated by the auxiliary line 116.

  Note that the light-emitting elements 104 to be mounted in the recesses are not necessarily inclined as shown in FIG. If one or more of the plurality of light emitting elements 104 are mounted substantially obliquely so that their side surfaces do not face each other, it is good for improving the light emission efficiency. In this way, the plurality of light emitting elements 104 may be arranged so as not to be shadowed with each other. In particular, when high luminance and white balance are required as a backlight, when a large number of light emitting elements 104 are mounted in one recess, it is necessary to increase the number of light emitting elements 104 with low luminance. Alternatively, with respect to the light emitting element 104 with low luminance, the mounting cost can be suppressed by increasing the chip size. In such a case, it is necessary to mount a plurality of chip sizes having different sizes and thicknesses in one recess. In such a case, as shown in FIG. 12, the light amounts emitted from the recesses can be increased by arranging the light emitting elements 104 so as not to be shadowed.

  Next, a more detailed description will be given with reference to FIG. FIG. 8 is a top view showing a state in which a plurality of light emitting elements are mounted substantially obliquely. FIG. 8 is a top view showing a state in which a plurality of light emitting elements 104 are arranged in a line. In FIG. 8, the plurality of light emitting elements 104 are mounted such that their side surfaces do not face each other. Here, by making them substantially oblique to each other, it is possible to effectively use light (illustrated by an arrow 110a) radiated in the lateral direction from at least the light emitting elements 104 adjacent to the left and right.

  In FIGS. 7 and 8, the column formed by the plurality of light emitting elements 104 does not cause any particular problem even if the centers thereof are slightly shifted. The center misalignment is desirably 200 microns or less when the chip size is 1 mm or more, 150 microns or less when the chip size is 0.5 mm or more, and 100 microns or less when the chip size is less than 0.5 mm. If the amount of deviation becomes larger than that, an optical influence may occur.

  Further, the angle at which the plurality of light emitting elements 104 are inclined (shown by arrows 110a to 110d in FIG. 8) is preferably 5 degrees or more and 85 degrees or less (preferably 10 degrees or more, more preferably 15 degrees or more). When the angle is less than 5 degrees, the plurality of light emitting elements 104 are substantially parallel to each other, and thus there is a case where the effect of improving the light emission efficiency at the side surface portion cannot be obtained. Note that the angle greater than 85 degrees is because the plurality of light emitting elements 104 are substantially parallel as in the case of less than 5 degrees.

  As shown in FIG. 8, (angle shown by arrow 110a) + (angle shown by arrow 110b) = (angle shown by arrow 110c) + (angle shown by arrow 110d) = 90 degrees. For example, when the angle indicated by the arrow 110a is 30 degrees, the angle indicated by the arrow 110b is 60 degrees.

  When a plurality of light emitting elements 104 are arranged in a planar shape (for example, a matrix), not only the inside but also the outermost periphery thereof, for example, as shown in FIG. 1 or FIG. By mounting so as not to face each other, light emitted from the side surface of the light emitting element mounted inside the matrix can be easily emitted to the outside.

  In order to mount a plurality of light emitting elements 104 on the lead frame 100 so that the side surfaces thereof do not face each other, for example, the heat radiation board shown in FIG. In this state, the light emitting element 104 is mounted while being shifted by a certain distance in both the X direction and the Y direction. Thereafter, the state shown in FIG. 1 is obtained by returning the angle at which the heat dissipation substrate is inclined (for example, 45 degrees).

(Embodiment 5)
In Embodiment 5, the shape (or top view) of the recess will be described with reference to FIG. 9A and 9B are a top view and a cross-sectional view illustrating the shape of the recess in Embodiment 5, for example, FIG. 9A is a top view of the light emitting module 112 of Embodiment 5, and FIG. 9B is FIG. This corresponds to a cross-sectional view taken along arrow 110 in FIG. Although the recesses shown in FIGS. 1A and 4A are round, the recesses shown in FIG. 9 show a shape such as an oval (or an ellipse or an oval). In FIG. 9B, reference numeral 124 denotes wire wiring (wiring formed by a wire bonder device), which electrically connects the light emitting element 104 and the second lead frame 100b.

  As shown in Embodiment Mode 5, the light emission in the case where the light emitting elements 104 are arranged in one row (or one oblique row) inside the concave portion by making the shape of the concave portion an oval (or oval shape, oval shape, etc.) The efficiency can be increased, and the light emitting module 112 can be reduced in size (particularly, the product width can be reduced).

(Embodiment 6)
In Embodiment 6, an example of a backlight using the light-emitting module 112 will be described. FIG. 10 is a perspective view of a backlight using the light emitting module 112. FIG. 10A is a perspective view showing the light emitting module 112 alone, and in FIG. 10A, 126 is a mounting hole, and a metal portion constituting the light emitting module 112 is formed in a portion protruding from the light emitting module 112. It has been done.

  FIG. 10B is a perspective view showing a state where a plurality of light emitting modules 112 are mounted. In FIG. 10B, reference numeral 128 denotes a heat radiating plate, and the light emitting module 112 can be fixed using the mounting hole 126. By fixing the metal plate 108 of the light emitting module 112 to the heat radiating plate 128 in this way, the heat radiating effect of the light emitting module 112 can be enhanced, and temperature variation among the plurality of light emitting modules 112 can be suppressed, and the light emission of each other can be achieved. The light quantity and white balance of the module 112 can be stabilized.

  In FIG. 10, a light guide plate, a light scattering plate and the like are not shown. As described above, as shown in Embodiment 6, even when a plurality of light emitting modules 112 (for example, 100 to 1000) are arranged as a backlight, heat dissipation and mounting properties, as well as power connection, can be achieved. This facilitates downsizing, thinning, and increasing the brightness of a display device using a backlight.

  In this way, a plurality of light emitting modules 112 are regularly fixed to a heat radiating member such as a heat radiating plate 128, whereby a backlight with reduced heat generation can be formed. By using this backlight, the image quality of a display device such as a liquid crystal is improved. be able to.

(Embodiment 7)
In Embodiment 7, an example of a backlight using the light emitting module 112 and a light guide plate will be described. FIG. 11 is a perspective view showing the relationship between the light guide plate and the light emitting module 112. In FIG. 11, reference numeral 130 denotes a light guide plate, which can uniformly diffuse light from the light emitting module 112 installed on the side surface over the entire surface of the light guide plate 130. As such a light guide plate 130, a highly transparent resin such as acrylic or PMMA (polymethyl methacrylate), which has been subjected to groove processing or hologram processing, can be used.

  In particular, since the light emitting module 112 proposed in Embodiment 7 can be formed with a narrow width, the backlight using the light guide plate 130 can be thinned (or narrowed in frame), and the display device using the backlight can be downsized. Can be made thinner and thinner.

(Embodiment 8)
In Embodiment 8, an example of a backlight using the light emitting module 112 and a diffusion plate will be described. FIG. 12 is a cross-sectional view showing the relationship between the light emitting module 112 and the diffusion plate. In FIG. 12, 132 is a diffusion plate and 134 is a liquid crystal panel. It can be seen that light radiated from the light emitting module 112 installed on the back surface of the diffusion plate 132 (arrows 110j and 110k indicate light in FIG. 12) is applied to the liquid crystal panel 134 through the diffusion plate 132.

  In this case, the surface of the resin 114 constituting the light emitting module 112 can be made into a lens shape, and the injection rate of light into the diffusion plate 132 can be increased. Further, the light emission efficiency can be increased by performing uniform light scattering using a predetermined groove or hologram on the diffusion plate 132, forming a light reflecting portion (for example, forming a mirror surface by vapor deposition of aluminum), or the like. Needless to say.

  Thus, at least the sheet-like heat radiation resin layer 106, the lead frame 100 partially embedded in the first surface of the heat radiation resin layer 106, and the metal plate 108 provided on the second surface of the heat radiation resin layer 106. And a plurality of light emitting elements 104 are mounted on the lead frame 100 such that their side surfaces do not face each other, whereby the light emitting module 112 emits light. Efficiency can be increased.

  Further, at least a sheet-like heat radiation resin layer 106, a lead frame 100 partially embedded in the first surface of the heat radiation resin layer 106, and a metal plate 108 provided on the second surface of the heat radiation resin layer 106. And providing a light emitting module 112 characterized in that one or more light emitting elements 104 are mounted on the lead frame 100 at an angle so that the side surfaces do not face each other. The light emission efficiency of the light emitting module 112 can be increased.

  Further, at least a sheet-like heat radiation resin layer 106, a lead frame 100 partially embedded in the first surface of the heat radiation resin layer 106, and a metal plate 108 provided on the second surface of the heat radiation resin layer 106. And a plurality of light emitting elements 104 are mounted substantially obliquely at an angle of 5 degrees or more and 85 degrees or less so that the side surfaces do not face each other in the concave portion of the lead frame 100. Even if the light emitting module 112 is a light emitting module 112 in which the surfaces of the lead frame 100 and the heat radiation resin layer 106 are substantially the same, the light emission efficiency of the light emitting module 112 can be increased. In addition, the mountability of the light emitting element 104 on the lead frame 100 is also improved.

  The light emitting elements 104 are mounted on the same first lead frame 100 and the light emitting elements 104 are electrically connected to the other plurality of lead frames 100 so that the light emitting module 112 can be connected. Facilitates circuit design.

  Further, the lead frame 100 occupies an area of 50% or more and 95% or less of the side surface forming the concave portion, so that the light emission efficiency by reflection at the surface portion of the lead frame 100 is increased.

  The plurality of light emitting elements 104 are light emitting elements 104 having at least two kinds of different light emission colors, thereby realizing improvement in light emission efficiency and white balance.

  In addition, the light emitting element 104 is mounted on the lead frame 100 having the largest area in the recess, and the light emitting element 104 is further mounted in the approximate center of the recess, so that the heat dissipation effect of the light emitting element 104 can be enhanced and the light emission efficiency can be improved. Enhanced.

  In addition, when one or more of the light emitting elements 104 has white light emission, white balance adjustment in the light emitting module 112 can be facilitated.

  The lead frame 100 is formed by punching a metal plate 108 having a thickness of 0.10 mm or more and 1.0 mm or less into at least a part of a three-dimensional concave shape. Reflection can be realized, and the light emission efficiency of the light emitting module 112 can be increased.

  Furthermore, the heat dissipation effect of the light emitting module 112 is enhanced by setting the thermal conductivity of the heat dissipation resin layer 106 to 1 W / (m · K) or more and 30 W / (m · K) or less.

The inorganic filler is the light emitting module 112 including at least one selected from the group consisting of Al ₂ O ₃ , MgO, BN, SiO ₂ , SiC, Si ₃ N ₄ , and AlN. To increase.

  The thermosetting resin is the light emitting module 112 including at least one selected from the group consisting of an epoxy resin, a phenol resin, and an isocyanate resin, so that the heat dissipation effect of the light emitting module 112 is enhanced.

  Further, by making the heat dissipation resin layer 106 white, the light reflectivity in the heat dissipation resin layer 106 can be increased, and the light emission efficiency of the light emitting module 112 can be increased.

  Further, the concave portion has a shape that narrows toward the bottom portion, and 50% to 95% of the concave portion area is formed in a state where a plurality of lead frames 100 are insulated from each other. The burr 120 generated in the light emitting module 112 is directed to the light emitting module 112 on which the light emitting element 104 is formed, so that the heat dissipation effect of the light emitting module 112 is enhanced.

  Sn is 0.1 wt% or more and 0.15 wt% or less, Zr is 0.015 wt% or more and 0.15 wt% or less, Ni is 0.1 wt% or more and 5 wt% or less, Si is 0.01 wt% or more and 2 wt% or less, Zn Is a lead frame mainly composed of copper containing one selected from the group consisting of 0.1 wt% and 5 wt%, P is 0.005 wt% and 0.1 wt%, and Fe is 0.1 wt% and 5 wt%. By using 100, the productivity, heat dissipation, and electrical characteristics of the light emitting module 112 are improved.

  Further, the lead frame 100 enhances the productivity, heat dissipation, and electrical characteristics of the light emitting module 112 by the light emitting module 112 made of tough pitch copper or oxygen-free copper.

  When the lead frame 100 processed into a predetermined shape, the thermosetting resin, and the metal plate 108 are molded, the antifouling film 122 is sandwiched and integrated with the surface where the lead frame 100 and the mold 118 are in contact with each other. A step of manufacturing a heat dissipation substrate, a step of mounting a plurality of light emitting elements 104 on the surface of the lead frame 100 so that the side surfaces thereof do not face each other, and a plurality of the light emitting elements 104 The light emitting module 112 can be produced by a method for manufacturing the light emitting module 112 having the step of sealing the substrate with the resin 114.

  Then, by proposing a display device having a backlight in which a plurality of the light emitting modules 112 described above are fixed to a heat radiating member or a heat radiating plate 128, the display device can be reduced in size and performance.

  As described above, by using the light emitting module 112 according to the present invention, a large number of the light emitting elements 104 can be stably lit. It can also be applied to high color rendering applications.

A top view and a cross-sectional view illustrating the light-emitting module according to Embodiment 1. Sectional drawing which shows an example of the manufacturing method of the light emitting module in this Embodiment 2. Sectional drawing which shows an example of the manufacturing method of the light emitting module in this Embodiment 2. The perspective view explaining the state which arranged the several light emitting element in the recessed part Top view explaining the problem of square array A perspective view when a plurality of light emitting elements are mounted in an oblique line A top view and a cross-sectional view showing a light emitting module according to Embodiment 4 A top view showing a state where a plurality of light emitting elements are mounted substantially obliquely. The top view and sectional view showing the shape of the concave portion in the fifth embodiment Perspective view of a backlight using a light emitting module The perspective view which shows the relationship between a light-guide plate and a light emitting module. Sectional drawing which shows the relationship between a light emitting module and a diffusion plate Sectional drawing which shows an example of light emitting module

Explanation of symbols

100a, 100b Lead frame 102 Dotted line 104 Light emitting element 106 Heat dissipation resin layer 108 Metal plate 110 Arrow 112 Light emitting module 114 Resin 116 Auxiliary wire 118 Mold 120 Burr 122 Antifouling film 124 Wire wiring 126 Mounting hole 128 Heat sink 130 Light guide plate 132 Diffusion Board 134 LCD panel

Claims (18)

At least a sheet-like heat dissipation resin layer;
A lead frame partially embedded in the first surface of the heat dissipation resin layer;
A metal plate provided on the second surface of the heat dissipation resin layer,
A light emitting module, wherein a plurality of light emitting elements are mounted on the lead frame such that the side surfaces do not face each other. At least a sheet-like heat dissipation resin layer;
A lead frame partially embedded in the first surface of the heat dissipation resin layer;
A metal plate provided on the second surface of the heat dissipation resin layer,
A light emitting module comprising a plurality of light emitting elements mounted on the lead frame at an angle so that the side surfaces do not face each other. At least a sheet-like heat dissipation resin layer;
A lead frame having a recess, part of which is embedded in the first surface of the heat dissipation resin layer;
A metal plate provided on the second surface of the heat dissipation resin layer,
A light emitting module, wherein a plurality of light emitting elements are mounted substantially obliquely at an angle of not less than 5 degrees and not more than 85 degrees so that the side surfaces do not face each other in the recess of the lead frame,
The light emitting module in which the surface of the said lead frame and the said heat radiation thermal radiation resin layer is substantially the same. 4. The light emitting device according to claim 1, wherein the light emitting device is electrically connected to another plurality of lead frames in a state where the plurality of light emitting devices are mounted on the same first lead frame. The light emitting module as described. The light emitting module according to any one of claims 1 to 3, wherein the lead frame occupies an area of 50% or more and 95% or less of the side surface forming the recess. The light emitting module according to any one of claims 1 to 3, wherein the plurality of light emitting elements are light emitting elements having at least two kinds of different emission colors. The light-emitting module according to claim 1, wherein the light-emitting element is mounted on a lead frame having the largest area in the recess, and the light-emitting element is further mounted in the approximate center of the recess. The light emitting module according to claim 1, wherein at least one of the light emitting elements has a white emission color. The light emitting module according to any one of claims 1 to 3, wherein the lead frame is formed by punching a metal plate having a thickness of 0.10 mm or more and 1.0 mm or less into a three-dimensional recess shape. 4. The light emitting module according to claim 1, wherein the heat dissipation resin layer has a thermal conductivity of 1 W / (m · K) to 30 W / (m · K). Inorganic _{filler, Al 2 O 3, MgO,} BN, SiO 2, SiC, Si 3 N 4, and a light emitting according to any one of claims 1 to 3 comprising at least one selected from the group consisting of AlN module. The light-emitting module 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. The light emitting module according to claim 1, wherein the heat dissipating resin layer is white. The recess has a shape that narrows toward the bottom, and 50% or more and 95% or less of the area of the recess is formed with a plurality of lead frames insulated from each other, and is generated at the end of the lead frame. The light emitting module according to claim 1, wherein the burr faces a side where the light emitting element is formed. 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 A lead frame mainly composed of copper containing one kind 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 light emitting module as described in any one of Claims 1-3 used. The light emitting module according to claim 1, wherein the lead frame is made of tough pitch copper or oxygen-free copper. A lead frame processed into a predetermined shape, a thermosetting resin, and a metal plate, when a mold is formed, a dirt prevention film is sandwiched and integrated on a surface where the lead frame and the mold are in contact to form a heat dissipation substrate; ,
Mounting a plurality of light emitting elements on the surface of the lead frame such that the side surfaces thereof do not face each other;
Sealing a plurality of the light emitting elements with a resin. A display device having a backlight in which a plurality of light emitting modules according to claim 1 are fixed to a heat sink.

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