JP4064412B2 - Light emitting element mounting substrate and light emitting element module - Google Patents

Description

  The present invention relates to a light emitting element mounting substrate for mounting a light emitting element such as a light emitting diode (hereinafter sometimes referred to as LED) and a light emitting element module including the same.

In order to integrate a plurality of light emitting diodes (LEDs) and make them into modules, chips, bullets, or surface mounted package LEDs are assembled on a substrate (hereinafter referred to as LEDs assembled on a substrate). LED module). For example, the LED module 50 shown in FIG. 5 has a large number of LEDs 52 arranged on a flat substrate 51. At the four corners of the substrate 51, through holes 53 for attachment are formed.
6 has a large number of cup structures 62 formed on the surface of a substrate 61 and an LED 63 mounted on the bottom of the cup structure 62 in order to improve the efficiency of extracting light emitted from the LEDs. . At the four corners of the substrate 61, through holes 64 for attachment are formed. As this type of LED module, for example, in Patent Documents 1 and 2, two metal substrates are combined, a cup processing portion is formed at a predetermined position of one metal substrate, and a light emitting element is provided at the bottom of the cup processing portion. A mounted lighting device is described.
In FIGS. 5 and 6, the electrodes and the like provided on the substrate are not shown.
JP 2001-332768 A JP 2001-332769 A

  In order to mount a large number of LEDs in an LED module using a cup structure, it is necessary to provide a large number of cup structures 62 on the surface of the substrate 61 as shown in FIG. In this case, as the number of the cup structures 62 is increased, as shown in FIG. Therefore, a deviation occurs between the central axis 65 of the substrate 61 and the neutral axis 66 in the thickness direction of the substrate 61. As a result, as shown in FIG. 8, warpage 67 may occur on the back surface of the substrate 61. Further, as shown in FIG. 5, even when the surface of the substrate 51 is flat, warping may occur. The warpage of the substrate is significant when the substrate is thin, when the substrate area is large, or in the longitudinal direction of the substrate.

Due to such warpage of the substrate, the flatness of the bottom of the cup structure may be lowered, and the LED mounting operation may be difficult. In addition, there is a problem in that the bonding between the LED and the substrate cannot be sufficiently obtained, and it becomes easy to peel. Furthermore, as shown in FIG. 9, since the substrate 61 has a warp 67, even when the radiator 70 is attached to the LED module 60, there is a gap 68 between the substrate 61 and the attachment plate portion 71 of the radiator 70. May occur, and sufficient contact between the substrate 61 and the radiator 70 may not be obtained. In this case, when the LED is driven at a high output or when a large number of LEDs are mounted and driven, the amount of heat generated from the LED cannot be efficiently radiated from the fins 72, and the temperature of the LED becomes high. There is also a problem that causes a decrease in luminous efficiency and lifetime.
In FIGS. 7 to 9, the electrodes and the like provided on the substrate are not shown.

  In order to improve the contact between the LED module 60 and the radiator 70, a heat conductive sheet or grease may be sandwiched between the gaps 68. However, in this case, there is a problem that the number of parts increases and the cost increases due to an increase in the number of assembly steps.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the light emitting element mounting board | substrate provided with this, and the board | substrate for light emitting element mounting with high heat dissipation and abundant mountability.

In order to solve the above problems, the present invention provides a light emitting element mounting substrate having a metal base material and a hollow layer covering the surface of the metal base material, wherein the light emitting element is mounted on the metal base material. A substrate body having a flat surface on the front side, and a heat dissipating portion comprising at least two or more plate-like fins protruding from the back surface of the substrate body, wherein the plate-like fins are mounted on the light emitting element. in the back position, the substrate along a longitudinal direction of the main body is provided in parallel to each other, wherein the planar surface of the metal base, the cup structure for reflecting light emitted from the light emitting element toward a predetermined direction is formed, the Provided is a substrate for mounting a light emitting element, wherein the fin and the cup structure are arranged to face the back and front of the substrate body.
The fin is preferably provided with at least one hole.
The present invention also provides a light emitting element module comprising a light emitting element mounted on the light emitting element mounting substrate.

  According to the present invention, by providing the fins integrally with the metal base material, the bending rigidity of the substrate body on which the light emitting element is mounted can be improved, and the influence of the heat shrinkage force can be reduced. Therefore, the flatness of the mounting surface of the light emitting element and the cup structure can be improved, and the mountability and reliability of the substrate can be improved. In addition, since a light emitting element module integrated with a heat radiator can be obtained, it is not necessary to insert a heat conductive sheet or grease, and the number of components and the number of assembly steps can be reduced. When the present invention is used as a lighting device, the light emitting surface of the light emitting element is arranged on the lower side and the fins of the radiator are arranged on the upper side, so that the heat on the radiator side easily escapes to the sky by natural convection, and the efficiency Heat dissipation can be performed.

  When the fin is provided on the back side of the mounting position of the light emitting element, the flatness of the mounting position can be further improved as compared with the case where the fin is provided at another position. In particular, when a cup structure is provided for the mounting position of the light emitting element, the digging depth of the cup structure can be increased. As a result, the degree of freedom in designing the cup structure is improved, and it becomes possible to improve the light distribution characteristics, the light extraction efficiency, and the like.

  When a hole is provided in the fin, it is not necessary to secure a region for providing a through hole for screwing the light emitting element module on the substrate body side, so that the degree of freedom regarding the arrangement of the light emitting element and the pattern of the electric wiring is improved. Can do.

The present invention will be described below with reference to the drawings based on the best mode.
FIG. 1 is a schematic configuration diagram illustrating an example of a light emitting element module according to the present invention. FIG. 1A is a plan view, FIG. 1B is a front view, and FIG. 1C is a side view. FIG. 2 is a drawing showing a mounting structure in which the light emitting element is mounted in a cup structure in the light emitting element module of this embodiment, FIG. 2 (a) is a schematic plan view, and FIG. 2 (b) is a detailed sectional view. . 3A is a cross-sectional view taken along line AA in FIG. 1A, and FIG. 3B is a cross-sectional view taken along line BB in FIG. 4 is a view showing a state in which the light emitting element module shown in FIG. 1 is attached to the main body. FIG. 4A is a front view and FIG. 4B is a side view.
In addition, in each figure of FIGS. 1-4 except FIG.2 (b), the electrode etc. which were provided on the board | substrate are abbreviate | omitting illustration.

  The light emitting element module 1 shown in FIG. 1 is obtained by mounting a large number of light emitting elements 15 on a light emitting element mounting substrate 11. As the light emitting element mounting substrate 11 of the present invention, a hollow substrate having a metal base 12 and a hollow layer 13 covering the surface of the metal base 12 is used (hereinafter, the light emitting element mounting substrate 11 is referred to as the enamel substrate 11). Sometimes). In the enamel substrate, the metal substrate 12 can be formed into a free shape by processing, and the enamel layer 13 can be formed on the metal substrate 12 having an arbitrary surface shape, so that electrical insulation is maintained. You can also

  The metal base 12 has the same shape as the heat sink. Specifically, the metal base 12 protrudes from the substrate body 2 having the flat surface 5 on the front side on which the light emitting element 15 is mounted, and the back surface 6 of the substrate body 2. It is set as the shape which has the heat-radiating part 4 which consists of at least 1 or more fins 3 and 3 ... which were made. The substrate body 2 can be mounted with the light emitting element 15 on the flat surface 5, but in order to improve the light extraction efficiency, the cup structure 14 that reflects the light emitted from the light emitting element 15 in a predetermined direction is provided. It is preferable to form on the front side of the substrate body 2 and mount the light emitting element 15 on the bottom of the cup structure.

  In FIG. 1, the mounting structure 10 in which the light emitting element 15 is mounted on the cup structure 14 is schematically shown. As shown in detail in FIG. 2 (b), the mounting structure 10 is divided into a light emitting element 15 mounted on the bottom surface of the cup structure 14 and a wire bond 16 connected to the light emitting element 15. It has electrodes 17 and 17 provided on the substrate 11. One of the electrodes 17, 17 is an electrode to which the light emitting element 15 is connected by die bonding or the like (not shown), and the other is an electrode connected to the light emitting element 15 through the wire bond 16. A substrate wiring pattern capable of driving the light emitting element 15 is provided on the flat surface 5 of the substrate body 2.

  In this embodiment, the cup structures 14 that are mounting positions for mounting the light emitting elements 15 are arranged vertically and horizontally on the metal substrate 12 with a predetermined interval. Note that the number of mounting positions of the light emitting elements 15 is not particularly limited, and may be at least one. The arrangement of the mounting positions of the light emitting elements 15 is not limited to the present embodiment, and can be appropriately designed.

  As a method of forming the cup structure 14 which is a mortar-shaped depression on the front side of the substrate body 2, cutting using a cutting tool such as a drill, drawing by a metal press (plastic processing), polishing using a carbide grindstone Processing or the like can be used. Of these, drawing by a metal press is preferable from the viewpoint of productivity and processing cost. The bottom surface of the cup structure 14 on which the light emitting element 15 is mounted is a plane having an area that sufficiently secures the mounting area of the light emitting element 15. The side surface surrounding the periphery of the bottom surface of the cup structure 14 is preferably a tapered inclined surface whose opening area increases toward the surface of the metal substrate 12.

  The metal substrate 12 of the enamel substrate 11 can be manufactured using various metal materials, and the material is not limited. However, the metal material is inexpensive and easy to process, for example, extremely low carbon steel, low carbon steel, stainless steel, etc. Steel is preferred. In Japanese Patent No. 2503778, it is described that glass treatment is performed on the surface of a copper heat sink. However, the copper material is more expensive than a steel material, and a material with high heat dissipation such as oxygen-free copper. Is difficult to form a precise cup structure with good reproducibility, and copper has half the modulus of elasticity compared to steel, so the rigidity of the substrate is low. Since warpage becomes large, it is not suitable for the purpose of producing a substrate for an LED module.

  In the example shown in FIG. 1, the shape of the metal base 12 is a rectangular plate shape and the fins 3 are parallel plates. However, the shape of the metal base material 12 is not particularly limited, and depends on the use of the light emitting element module 1 or the like. Appropriate selection is possible. For example, the shape of the fin 3 may be a plate having a taper whose thickness decreases toward the tip, or a pin. In order to improve the performance as a radiator, it is preferable that the heat radiating section 4 has at least two fins 3. A black paint or the like for improving heat dissipation may be applied to the surface of the fin 3.

  When plate-like fins are employed as the fins 3, 3,..., It is preferable that the fins 3, 3,. Here, the longitudinal direction of the substrate body 2 refers to a direction in which the dimension along the flat surface 5 on the front side of the substrate body 2 is the largest. Thereby, especially the bending rigidity of the longitudinal direction of the board | substrate body 2 can be improved.

  Moreover, it is preferable that the position where the fin 3 is provided to be projected is on the back side of the mounting position of the light emitting element 15. Thereby, compared with the case where the fin 3 protrudes from the other position in the back surface 6 of the board | substrate body 2, the flatness of a mounting position can be improved further. In particular, when the cup structure 14 is provided for the mounting position of the light emitting element 15, the digging depth of the cup structure 14 can be increased. As a result, the degree of freedom in designing the cup structure 14 is improved, and it becomes possible to improve light distribution characteristics, light extraction efficiency, and the like. For this reason, a heat sink-shaped blank having a flat surface of the substrate body 2 is prepared, and the cup structure 14 is formed with the back side of the fin 3 as a target. It can be set as the arrangement which opposes.

  In the case of the enamel substrate 11 of this embodiment, two through holes 18 on both sides of the fins 3, 3, 3 are provided with mounting through holes 18 (two per fin, a total of four). Thus, by providing the mounting holes 18 in the fins 3, it is not necessary to secure a region on the substrate body 2 side where the through holes 18 for screwing the light emitting element module 1 to the body portion 20 are provided. The degree of freedom regarding the arrangement of the light emitting elements 15 and the pattern of the electrical wiring can be improved. The number and arrangement of the through holes 18 for mounting are not limited to the illustrated embodiment, and can be appropriately designed according to the use of the light emitting element module 1 and the structure of the main body 20.

  In the case of this embodiment, as shown in FIG. 4, by providing a female screw part (screw hole) 21 on the main body part 20 side and using a bolt (male screw) as the mounting member 22, the inner surface of the through hole 18 is a smooth surface. It is said. Then, by aligning the positions of the female screw portion 21 provided in the main body portion 20 and the through holes 18 provided in the fins 3 and fastening them with the fixing bolts 22, the main body portion 20 (for example, the case) is obtained. Can be attached.

  The hole 18 provided in the fin 3 can take various forms depending on the type of attachment member 22 and the attachment method. For example, a screw hole having a female screw, a blind hole for closing one end, a hole having an engagement portion or a fitting portion inside, and the like can be used. Another example of the mounting hole applicable to the enamel substrate 11 is a screw hole of the type described in JP-A-4-129287. The screw hole described in the publication has a groove without a hollow layer that isolates the conductive circuit region of the enamel substrate and the screwed portion of the enamel substrate from each other. The circuit portion can be secured without affecting the portion.

  The material of the enamel layer 13 provided on the surface of the metal substrate 12 can be selected from materials mainly made of glass used for forming an enamel layer on the metal surface. Of these, an alkali-free glass material is preferable. Although the method for forming the enamel layer 13 is not particularly limited, for example, the following method can be used.

  First, a glass powder as a raw material is dispersed in an appropriate dispersion medium such as 2-propanol, a portion where the enamel layer 13 is to be provided on the metal base 12 is immersed in the dispersion medium, and an electrode serving as a counter electrode is also the same. The glass powder is electrodeposited onto the desired surface of the metal substrate 12 by putting it in a dispersion medium and energizing between the metal substrate 12 and the counter electrode. Thereafter, the enamel layer 13 made of glass can be firmly coated on the desired surface of the metal substrate 12 by baking the glass powder in the air. In order to coat more firmly, the surface of the metal substrate 12 (low carbon steel) may be oxidized.

  The enamel layer 13 may be provided at least on the front side of the substrate body 2, that is, on the flat surface 5 and in the cup structure 14 in order to ensure electrical insulation. The thickness of the enamel layer 13 is not particularly limited, but the surface having the cup structure 14 is preferably in the range of 50 μm to 200 μm. The side surface and the back surface 6 of the substrate body 2 are not sufficiently electrodeposited with glass, and the thickness in the above numerical range may not be satisfied. Since it is not required, the function can be satisfied by sufficiently performing a rust prevention treatment on the metal base 12.

  Although it does not specifically limit as the light emitting element 15, Semiconductor light emitting elements, such as a light emitting diode (LED) and a laser diode (LD), are used suitably. The light emission color of the light emitting element 15 is not particularly limited, and may be blue, green, red, or any other light emission color. Specific examples include a blue light emitting element such as a nitride compound semiconductor, a green light emitting element, a red light emitting element represented by gallium phosphide (GaP), an infrared light emitting element, and the like. Further, a blue light emitting element such as a nitride compound semiconductor is mounted in the cup structure 14, and a blue excited yellow light emitting phosphor (for example, yttrium activated with cerium is used in a sealing resin (described later) for sealing the cup structure 14. An aluminum garnet phosphor) may be included to constitute a white LED. The phosphor to be contained is not limited to yellow light emission, and may be a color such as green or red, and two or more kinds may be mixed.

  When the plurality of cup structures 14 are provided on the enamel substrate 11 and the light emitting elements 15 are mounted side by side, the type and emission color of each light emitting element 15 are not particularly limited. For example, for applications such as traffic signals, the emission color of the light emitting element 15 may be uniform, or in the case of a display device, LEDs of different emission colors may be arranged regularly or irregularly. . Furthermore, a display device can be configured by arranging a large number of pixels composed of combinations of blue LEDs, green LEDs, and red LEDs on a large-area enamel substrate 11. Further, a white LED is used as the light emitting element 15 and a large number of white LEDs are mounted vertically and horizontally on the enamel substrate 11, whereby a large area planar illumination device can be configured.

  As the wire bond 16, a metal wire made of gold (Au) or the like is used. The wire bond 16 can be connected by using a wire bonding apparatus conventionally used for connecting the light emitting element 15 and the like.

  The electrode 17 provided on the upper surface of the enamel substrate 11 can be formed to extend from the outside to the inside of the cup structure 14 with, for example, a thick film silver paste. Alternatively, the electrode 17 can be formed by press-molding a copper foil and mounting it on the cup structure 14.

In the cup structure 14, a sealing resin having a high light transmittance can be provided to seal the light emitting element 15 and the connection portion between the light emitting element 15 and the electrode 17 as necessary. As the sealing resin, an appropriate transparent resin can be used. Specific examples thereof include a thermosetting epoxy resin, an ultraviolet curable epoxy resin, and a silicon resin.
In the mounting structure 10 of the light emitting element 15 shown in FIG. 2, the electrode 17 is exposed on the flat surface 5 which is the upper surface of the enamel substrate 11, but resin or the like is used to ensure electrical insulation in the exposed portion. An electrical insulator may be provided.
In addition, a lens body made of a transparent medium such as resin or glass can be combined as necessary above the sealing resin or above the entire light emitting element module 1.

  As described above, according to the light emitting element mounting substrate 11 of the present embodiment, the bending rigidity of the substrate body 2 on which the light emitting element 15 is mounted is improved by integrally providing the fins 3 on the metal base 12. The influence of heat shrinkage force can be reduced. Therefore, the flatness of the mounting surface of the light emitting element 15 and the cup structure 14 is improved, and the mountability and reliability of the substrate can be improved. Moreover, since the light emitting element module 1 in which the heat radiating part 4 functioning as a heat radiator is integrated can be obtained, it is not necessary to insert a heat conductive sheet or grease, and the number of components and the number of assembly steps can be reduced. Become. When the light emitting element module 1 of this embodiment is used as a lighting device, the light emitting surface of the light emitting element 15 is disposed on the lower side and the fins 3 of the heat radiating section 4 are disposed on the upper side. It becomes easy to escape to the sky by convection, and efficient heat dissipation can be performed.

  The present invention can be used for various products on which light emitting elements such as LEDs are mounted, for example, lighting devices, display devices, traffic signals, and the like.

It is a schematic block diagram which shows an example of the light emitting element module of this invention, (a) is a top view, (b) is a front view, (c) is a side view. In the light emitting element module shown in FIG. 1, it is drawing which shows the mounting structure which mounts a light emitting element in a cup structure, (a) is a schematic plan view, (b) is detailed sectional drawing. (A) is sectional drawing which follows the AA line of Fig.1 (a), (b) is sectional drawing which follows the BB line of Fig.1 (a). It is drawing which shows the state which attached the light emitting element module shown in FIG. 1 to the main-body part, (a) is a front view, (b) is a side view. It is the schematic which shows an example of the conventional light emitting element module, (a) is a top view, (b) is sectional drawing. It is the schematic which shows the other example of the conventional light emitting element module, (a) is sectional drawing which follows CC line, (b) is sectional drawing which follows DD line. FIG. 7 is a schematic diagram illustrating a deviation between a central axis and a neutral axis of a substrate of the light emitting element module illustrated in FIG. 6. It is the schematic explaining the curvature of the board | substrate of the light emitting element module shown in FIG. It is sectional drawing which shows the state which attached the board | substrate shown in FIG. 8 to the heat radiator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light emitting element module, 2 ... Board | substrate main body, 3 ... Fin, 4 ... Radiation part, 5 ... Flat surface, 6 ... Back surface, 11 ... Light emitting element mounting substrate (enamel substrate), 12 ... Metal base material, 13 ... Enamel Layers 14 ... Cup structure 15 ... Light emitting element 18 ... Hole (mounting hole).

Claims (3)

A light-emitting element mounting substrate having a metal substrate and a hollow layer covering the surface of the metal substrate,
The metal base has a substrate body having a flat surface on the front side on which the light emitting element is mounted, and a heat radiating portion made of at least two plate-like fins protruding from the back surface of the substrate body,
The plate-like fins are provided in parallel to each other along the longitudinal direction of the substrate body on the back side of the mounting position of the light emitting element ,
A cup structure that reflects light emitted from the light emitting element in a predetermined direction is formed on the flat surface of the metal base, and the fin and the cup structure are arranged to face the back and front of the substrate body . A substrate for mounting a light emitting element. The light emitting element mounting substrate according to claim 1 , wherein at least one hole is provided in the fin. A light-emitting element module comprising a light-emitting element mounted on the light-emitting element mounting substrate according to claim 1 .

Images