JP4343137B2 - Light emitting element mounting substrate, light source, illumination device, display device, traffic signal device, and method for manufacturing light emitting element mounting substrate - 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 referred to as LED), a light source formed by mounting the light emitting element on the substrate, an illumination device including the light source, and a display. The present invention relates to a device, a traffic signal device, and a method for manufacturing a light emitting element mounting substrate .

In order to protect the light-emitting element from an external environment such as external force and moisture, the light-emitting element is usually mounted on a substrate and packaged by sealing the light-emitting element with a transparent resin. Furthermore, in order to control the light emitted from the light emitting element such as condensing and diffusing, a lens-shaped protrusion may be formed on the sealing resin. In order to produce such a lens shape, for example, the resin before curing is raised by surface tension, and the upper part of the sealing resin is finished into a lens shape by heat curing or ultraviolet curing while maintaining the shape. (For example, refer to Patent Document 1).
In such a lens-shaped manufacturing method, the raised amount of the resin to be raised is greatly influenced by the wettability between the substrate and the resin. For example, if the amount of sealing resin applied is too large due to variations in the surface condition of the substrate or if the wettability of the substrate surface is good, the uncured resin will flow out on the upper surface of the substrate. It takes time to remove, and in some cases, the resin that has flowed out covers the electrode provided on the side of the substrate, etc., and the resin attached to the electrode becomes an electrical insulating film when trying to fix the substrate with solder There is a problem that leads to poor conduction.

  In recent years, LEDs have been applied to lighting applications, traffic signals, and the like, and further improvements in emission intensity are required. The light emission intensity of the LED can be increased by increasing the amount of current to be applied. However, in this case, since the light emitting element simultaneously generates heat, it is necessary to efficiently dissipate heat. When the heat radiation is not sufficient, the light emitting element becomes high temperature during lighting, and thus the light emission efficiency is lowered, and the target light emission intensity cannot be obtained. Moreover, when using for a long term, the reliability of LED falls and possibility that malfunctions, such as non-lighting, will generate | occur | produce becomes high.

Further, in order to efficiently emit light emitted from the light emitting element forward, it is desirable to provide a reflective recess as shown in FIG. In the package structure of the light emitting element shown in FIG. 4, a package 1 having a mortar-shaped reflective recess 2 and a part of which is provided with an electrode 3 extending into the reflective recess 2 is used. A light emitting element 4 such as an LED is mounted on one electrode 3 in the reflective recess 2, the light emitting element 4 and the other electrode 3 are electrically connected by a gold wire 5, and sealed in the reflective recess 2 The lens 6 is formed by filling and curing the resin 6 so that the upper part is raised. The light source of this package structure turns on the light emitting element 4 by energizing between the electrodes 3, part of the light emitted from the light emitting element 4 is directly emitted, and the other part is reflected by the reflecting recess 4 and emitted. The light emitted from the light emitting element 4 can be emitted to the front of the package efficiently.
JP-A-9-153646

As a substrate having good heat dissipation, for example, an enamel substrate 9 as shown in FIG. 5 is conceivable. The enamel substrate 9 is configured by covering the surface of the core metal 7 on which the mortar-shaped reflective recess 11 is formed with a thin enamel layer 8 made of glass or the like. On the enamel layer 8, an electrode 3 partially extending in the reflective recess 11 is provided. .
The enamel substrate 9 having the reflective recesses 11 as shown in FIG. 5 needs to be processed so that the core metal 7 has the shape of the reflective recesses 11. Examples of this processing method include processing using a drill and drawing processing using a metal press. From the viewpoint of productivity and processing cost, it is desirable to use press processing.

  However, when drawing with a metal press, if the shape of the core metal is not particularly taken into consideration, the entire substrate may be warped or the metal may escape locally due to the pressing force of the metal press, resulting in bulges and protrusions. As a result, there is a problem that post-processing is necessary for these corrections, and production efficiency deteriorates. 6A and 6B are diagrams illustrating bulges and protrusions that are likely to occur in the drawing process of the core metal. FIG. 6A is a cross-sectional view of the core metal 7 to be manufactured, and FIG. FIG. 4C is a cross-sectional view showing a case where a bulge 12 is generated, and FIG. It takes a lot of labor and time to generate these blisters 12 and protrusions 13 and correct them by grinding or the like.

The present invention has been made in view of the above circumstances, a light emitting element mounting substrate comprising a hollow substrate with a reflective recess capable of efficiently producing a hollow substrate having a reflective recess at a low cost, a light source formed by mounting the light emitting element on the substrate, It is an object of the present invention to provide an illumination device, a display device, a traffic signal device, and a method for manufacturing a light emitting element mounting substrate including the light source.

In order to achieve the above object, the present invention provides a light-emitting element mounting substrate in which a core metal surface is coated with a hollow layer and provided with a reflective recess for mounting a light-emitting element, on the outer periphery of the reflective recess. A light-emitting element mounting substrate is provided , wherein a groove is provided concentrically with the reflective recess .

  The present invention also provides a light source characterized in that a light emitting element is mounted in the reflective recess of the light emitting element mounting substrate.

  In the light source of the present invention, it is preferable that the inside of the reflective recess is sealed with resin, and the upper portion of the sealing resin protrudes into a lens shape.

  Moreover, this invention provides the illuminating device characterized by having the light source which concerns on this invention mentioned above.

  The present invention also provides a display device comprising the light source according to the present invention described above.

Moreover, this invention provides the traffic signal characterized by having the light source which concerns on this invention mentioned above.
The present invention is made by coating the surface of the core metal by enamel layer, The method for manufacturing a light emitting element mounting substrate for reflecting recesses are provided for mounting a light emitting device, the metal plate as a core metal, the outer periphery of the forming position of the reflective concave portion, wherein a groove is formed in the reflective concave portion and concentrically, to the central portion of the metal plate to which the groove is formed, to form the reflective concave portion is subjected to processing by metal stamping Provided is a method for manufacturing a substrate for mounting a light-emitting element, characterized in that a core metal is produced and then the surface of the core metal is covered with a hollow layer .

Since the light emitting element mounting substrate of the present invention uses a hollow substrate in which a groove is formed around the reflective recess for mounting the light emitting element, when the core metal is produced by drawing with a metal press, the core metal is warped. The reflective recess can be formed without deformation, and it is not necessary to perform post-processing for correcting the deformation and the like, and the substrate can be manufactured efficiently and inexpensively.
In addition, since a groove is formed around the reflective recess, even if a large amount of sealing resin is applied, the resin does not flow out to the outside of the substrate, and an electric insulating film is formed on the electrode surface by the flowed resin. Can be prevented.
In addition, since the structure is such that the light emitting element is mounted on the hollow substrate whose core is a metal, the heat dissipation is good, even when a large number of light emitting elements are mounted, even when the amount of power to be energized per light emitting element is increased. Therefore, it is possible to suppress a decrease in light emission efficiency due to a temperature rise, and to improve the light emission intensity as expected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1-3 is a figure which shows one Embodiment of this invention, FIG. 1 shows an example of the core metal 21 used for the light emitting element mounting board | substrate of this invention, Fig.1 (a) is a core metal. 21 is a side view, and FIG. FIG. 2 is a cross-sectional view showing an example of the light emitting element mounting substrate 20 of the present invention. 3 is a cross-sectional view showing an example of the light source 28 according to the present invention configured by mounting the light emitting element 29 on the light emitting element mounting substrate 20 shown in FIG.

  Mainly a hollow substrate formed by coating a hollow layer 22 on the surface of the core metal 21 shown in FIG. 1 in which a reflective recess 23 serving as a mounting position of the light emitting element 29 on one surface side and a groove 24 is provided around the reflective recess 23. In this configuration, a pair of electrodes 27 partially extending in the reflective recesses 23 are provided on one surface side of the hollow substrate.

The reflective recess 23 formed in the light emitting element mounting substrate 20 has a mortar shape, and has a flat bottom surface 25 on which the light emitting element 29 is mounted, and a tapered surface 26 on the periphery thereof.
Moreover, the groove | channel 24 provided in the circumference | surroundings of the reflective recessed part 23 is concentrically provided in the outer periphery of the reflective recessed part 23 in this illustration.

The material of the core metal 21 is preferably a metal material having good thermal conductivity and capable of firmly baking the enamel layer 22, for example, a low carbon steel plate.
Moreover, the material of the enamel layer 22 is preferably a material that can be thinly baked on the surface of the core metal 21 and can obtain sufficient electrical insulation, and for example, glass is desirable.

  The light source 28 shown in FIG. 3 uses the light emitting element mounting substrate 20 described above, and a light emitting element 29 is mounted on one electrode 27 extended on the bottom surface 25 of the reflective recess 23 by die bonding or the like. The element 29 and the other electrode 27 are connected by a gold wire 30, and the inside of the reflective recess 23 is sealed with a sealing resin 31 with the upper part raised.

  The light emitting element 29 may be a blue light emitting element or a green light emitting element such as a nitride compound semiconductor, or may be a red or infrared light emitting element represented by GaP. Also, a blue light emitting element such as a nitride compound semiconductor is mounted, and a blue excited yellow light emitting phosphor such as yttrium, aluminum, and garnet phosphor activated with cerium is dispersed in the sealing resin 31 to obtain a white color. It is good also as LED.

Next, a method for manufacturing the light emitting element mounting substrate 20 will be described.
First, the groove 24 is formed around the position where the reflective recess 23 is formed in the metal plate used as the core metal 21. This groove 24 is preferably formed by drilling or the like.
Next, the metal plate is subjected to a drawing process using a metal press to form a reflective recess 23 to produce a core metal 21 having a shape shown in FIG.

  By providing the groove 24 in the outer periphery of the position where the reflective recess 23 is formed in advance, when the reflective recess 23 is formed on the metal plate by drawing with a metal press, the stress generated when the reflective recess 23 is produced by pressing pressure is Since it occurs in the direction of the groove 24, it is possible to prevent the entire metal plate from being warped or part of the metal plate from expanding.

  Also, by keeping the width of the groove 24 wider, the groove 24 with a certain amount of width remains even after the metal escapes after the drawing process. When the groove 24 remains, the substrate surface is enameled, and electrodes are formed. When the light source 28 is manufactured using the light emitting element mounting substrate 20, the sealing resin 31 flows out of the reflective recess 23. However, this can be stopped by the groove 24 to prevent the resin from flowing out to other parts.

  Next, glass is baked on the surface of the core metal 1, and the surface of the core metal 21 is covered with the enamel layer 22 to form an enamel substrate. As a method for forming the enamel layer 22, for example, glass powder is dispersed in a suitable dispersion medium such as 2-propanol, the core metal 21 is placed in the dispersion medium, and an electrode serving as a counter electrode is placed in the dispersion medium. The glass powder is electrodeposited on the surface of the core metal 21 by being inserted and disposed and energized between the core metal 21 and the counter electrode. Thereafter, the core metal 21 after the electrodeposition of the glass is pulled up, dried, put in a high-temperature baking furnace, heated, and the glass is baked to form a dense and uniform thin enamel layer 22 on the surface of the core metal 21. it can. Furthermore, in order to coat the enamel layer 22 firmly, the surface of the core metal 21 may be oxidized.

  Next, a pair of electrodes 27 for supplying power to the light emitting element 29 is formed on the surface of the enamel substrate manufactured as described above. As shown in FIG. 2, the electrode 27 is preferably manufactured by applying a silver paste or a copper paste along a pattern such that a part of the electrode 27 extends into the reflective recess 23 and then baking the paste. Thus, the light emitting element mounting substrate 20 shown in FIG. 2 is manufactured.

  Next, the light emitting element 29 is die-bonded on one electrode 27 in the reflective recess 23 with silver paste, and further, wire bonding is performed to connect the light emitting element 29 and the other electrode 27 with the gold wire 30. Thereafter, a sealing resin, for example, a thermosetting epoxy resin, is injected into the reflective recess 23 until the upper part is sufficiently raised by the surface tension, and is cured while maintaining its shape. Form. Thereby, the light source 28 shown in FIG. 3 is produced.

Since the light emitting element mounting substrate 20 of the present embodiment uses a hollow substrate having grooves 24 formed around the reflective recesses 23 for mounting the light emitting elements 29, the core metal 21 is produced by drawing with a metal press. The reflective recess 23 can be formed without the core metal 21 being warped or deformed, and there is no need to perform post-processing for correcting the deformation or the like, and the substrate can be produced efficiently and inexpensively.
Further, since the grooves 24 are formed around the reflective recesses 23, even when a large amount of the sealing resin 31 is applied, the resin does not flow out to the outside of the substrate, and the electrically insulating film is formed on the electrode surface by the discharged resin. It is possible to prevent the problem that the is formed.
In addition, since the light emitting element 29 is mounted on a hollow substrate whose core is a metal, the heat dissipation is improved, and when a large number of light emitting elements are mounted, the amount of power to be energized per light emitting element is increased. However, a decrease in light emission efficiency due to a temperature rise can be suppressed, and the light emission intensity can be improved as expected.

In the above-described example, the description has been made on the premise of pressing (drawing). However, even when the reflective recess is formed in the core metal by other machining such as drilling, by providing a groove around the reflective recess. Needless to say, it is effective in preventing the resin from flowing out when the lens body is formed of the sealing resin.
Further, in the above-described example, the case where one reflecting recess is formed on the enamel substrate has been described, but a plurality of reflecting recesses having grooves around may be provided on the enamel substrate.

  A circular groove was formed in a 1.5 mm thick low carbon steel plate by a drill at the periphery of a position where a reflective recess is to be formed by drawing with a metal press. The dimensions were processed so that the inner circumference was φ10 mm, the outer circumference was φ12 mm, and the depth was 0.5 mm. Thereafter, a metal plate was punched out and a reflective recess was formed by metal pressing so as to have a shape as shown in FIG. The size of the core metal was 15 × 15 mm, and the dimensions of the reflective recess were made such that the depth was 0.6 mm, the bottom surface was φ2.1 mm, and the inclination angle of the tapered surface was 45 °. As a result, it was confirmed that the dimensions of the reflective recess were almost as designed, and the width of the groove was initially reduced to an average of about 0.8 mm.

An example of the core metal used for the light emitting element mounting board | substrate of this invention is shown, (a) is sectional drawing of a core metal, (b) is a top view. It is sectional drawing which shows an example of the light emitting element mounting substrate of this invention. It is sectional drawing which shows an example of the light source of this invention. It is sectional drawing which illustrates the package structure of the conventional light emitting element. It is sectional drawing which shows an example of an enamel substrate. It is sectional drawing which illustrates the swelling and protrusion which arise at the time of processing of a core metal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Light emitting element mounting substrate, 21 ... Core metal, 22 ... Hollow layer, 23 ... Reflective recess, 24 ... Groove, 25 ... Bottom surface, 26 ... Tapered surface, 27 ... Electrode, 28 ... Light source, 29 ... Light emitting element, 30 ... gold wire, 31 ... sealing resin.

Claims (7)

A substrate for mounting a light emitting device, wherein the surface of the core metal is covered with a hollow layer and provided with a reflective recess for mounting the light emitting device,
A substrate for mounting a light emitting element, characterized in that a groove is provided on the outer periphery of the reflective concave portion so as to be concentric with the reflective concave portion.   A light source, wherein a light emitting element is mounted in the reflection recess of the light emitting element mounting substrate according to claim 1.   The light source according to claim 2, wherein the inside of the reflective recess is sealed with resin, and an upper portion of the sealing resin protrudes in a lens shape.   An illumination apparatus comprising the light source according to claim 2.   A display device comprising the light source according to claim 2.   A traffic light having the light source according to claim 2. A method for manufacturing a substrate for mounting a light emitting element, wherein the surface of the core metal is covered with a hollow layer and provided with a reflective recess for mounting the light emitting element.
A metal plate as a core metal is formed with a groove concentrically with the reflection recess on the outer periphery of the position where the reflection recess is formed, and the metal plate on which the groove is formed is processed by a metal press. Forming the reflective recesses to produce a core metal, and then coating the surface of the core metal with a hollow layer .

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