JP4949303B2 - LIGHT SOURCE AND ITS MANUFACTURING METHOD, LIGHTING DEVICE, DISPLAY DEVICE, AND TRAFFIC SIGNAL - Google Patents

Description

  The present invention relates to a light source that is mounted on a light emitting element mounting substrate for mounting a light emitting element such as a light emitting diode (hereinafter referred to as LED), a method for manufacturing the light source, an illumination device including the light source, a display device, It relates to traffic signals.

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, and the resin attached to the electrode becomes an electrical insulating film when the substrate is fixed 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, and includes a light source formed by mounting a light emitting element on a light emitting element mounting substrate made of a hollow substrate with a reflective recess, which can efficiently produce a hollow substrate having a reflective recess at low cost, and the light source. An object is to provide a lighting device, a display device and a traffic signal.

In order to achieve the above object, the present invention provides a light emitting element mounting substrate comprising a core metal, a hollow layer covering the surface of the core metal, and an electrode pattern formed on the surface of the hollow layer; A light source comprising a light emitting element mounted on an element mounting substrate and a sealing resin covering the light emitting element,
The light emitting element is mounted in a reflective recess of a light emitting element mounting substrate provided by forming a recess in the core metal,
Around the reflective recess, the stress generated during core metal pressing is relaxed, and the sealing resin is prevented from flowing out when the light emitting element mounted on the reflective recess is sealed with the sealing resin. There is provided a light source characterized in that a groove is formed , the reflecting recess is circular, and the groove is provided concentrically on the outer periphery of the reflecting recess .

In the light source of the present invention, it is preferable that a plurality of the reflective recesses having the groove around are provided on the light emitting element mounting substrate .

  In the light source of the present invention, it is preferable that an upper portion of the sealing resin protrudes in a lens shape.

In addition, the present invention provides a core metal, and reduces the stress generated at the time of core metal pressing by drilling on the outer periphery of the position where the reflective recess of the core metal is to be formed, and the light emitting device mounted on the reflective recess. When the element is sealed with a sealing resin, a groove for preventing the sealing resin from flowing out is formed concentrically .
Next, the core metal is pressed to form a circular reflective recess,
Next, a hollow substrate is formed by forming a hollow layer on the surface of the core substrate,
Next, an electrode pattern is formed on the surface of the hollow substrate to produce a light emitting element mounting substrate,
Next, the light emitting element is mounted in the reflective recess of the light emitting element mounting substrate,
Next, the light emitting device mounted in the reflective recess is sealed with a resin, and the above-described light source manufacturing method is provided.

  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.

Since the light source 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 or deformed. Therefore, it is possible to form a reflective concave portion without the need for post-processing for correcting deformation and the like, and it is possible to manufacture a substrate 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 source of this invention, Fig.1 (a) is a side view of the core metal 21 , (B) is a plan view. FIG. 2 is a cross-sectional view showing an example of the light emitting element mounting substrate 20 used in the light source of the present invention. 3 is a cross-sectional view showing an example of the light source 28 of the present invention configured by mounting the light emitting element 29 on the light emitting element mounting substrate 20 shown in FIG.

  The light emitting element mounting substrate 20 used for the light source of the present invention has a reflective recess 23 which is a mounting position of the light emitting element 29 on one surface side, and a core metal 21 shown in FIG. The surface is mainly composed of an enamel substrate that covers the enamel layer 22, and a pair of electrodes 27 that are partially extended to the reflective recesses 23 are provided on one surface side of the enamel substrate. Yes.

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, an example of the manufacturing method of the light source of this invention is demonstrated.
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. The groove 24 is formed by drilling.
Next, the metal plate is subjected to a drawing process using a metal press to form a reflective recess 23 to produce the core metal 21 having the 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 press working (drawing). However, even when the reflective recess is formed in the core metal by other machining such as drilling, a groove is provided 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 on a peripheral edge at a position where a reflective concave portion was to be formed on a 1.5 mm-thick low carbon steel plate by drawing with a metal press. The dimensions were processed so that the inner diameter was 10 mm, the outer diameter was 12 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 source 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 used for the light source 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 light emitting element mounting substrate comprising a core metal, a hollow layer covering the surface of the core metal, and an electrode pattern formed on the surface of the enamel layer; and a light emitting element mounted on the light emitting element mounting substrate; A light source comprising a sealing resin covering the light emitting element,
The light emitting element is mounted in a reflective recess of a light emitting element mounting substrate provided by forming a recess in the core metal,
Around the reflective recess, the stress generated during core metal pressing is relaxed, and the sealing resin is prevented from flowing out when the light emitting element mounted on the reflective recess is sealed with the sealing resin. Grooves are formed ,
The light source, wherein the reflective recess is circular and the groove is provided concentrically on the outer periphery of the reflective recess . 2. The light source according to claim 1, wherein a plurality of the reflective recesses having the groove around are provided on the light emitting element mounting substrate .   The light source according to claim 1, wherein an upper portion of the sealing resin protrudes in a lens shape. The core metal is prepared, and the stress generated during the core metal press processing is reduced by drilling on the outer periphery of the position where the core metal reflective recess is to be formed, and the light emitting element mounted in the reflective recess is sealed with resin Forming a groove to prevent the sealing resin from flowing out concentrically when sealing with,
Next, the core metal is pressed to form a circular reflective recess,
Next, a hollow substrate is formed by forming a hollow layer on the surface of the core substrate,
Next, an electrode pattern is formed on the surface of the hollow substrate to produce a light emitting element mounting substrate,
Next, the light emitting element is mounted in the reflective recess of the light emitting element mounting substrate,
Then, the light emitting element mounted in the reflective recessed part is sealed with resin, and the light source manufacturing method characterized by obtaining the light source as described in any one of Claims 1-3. It has the light source as described in any one of Claims 1-3, The illuminating device characterized by the above-mentioned. Display device, characterized in that a light source according to any one of claims 1 to 3. Traffic signal, characterized in that it has a light source according to any one of claims 1 to 3.

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