JP2005244121A - Light emitting diode package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting diode package which has a good light reflecting face for reflecting luminescence light flux from an LED element to an external part, whose manufacture is simple and in which dispersion of luminance and an angle of visibility is small. <P>SOLUTION: Mounting region of the LED element is formed on a ceramic substrate and a metallized layer is formed on the ceramic substrate along a route surrounding the LED element. A metallic ring is brazed to the metallized layer. The metallized layer is created with an allowance so that it also exists inside the ring. A fillet formed of a Ag brazing material is formed over the metallized layer existing inside the ring and the ring. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light emitting diode package.

  In recent years, attention has been focused on light emission diodes (hereinafter also referred to as LED elements). In particular, since high-luminance blue light-emitting diodes can be manufactured, high-luminance white light can be obtained using red, green, and blue LED elements, and these LED elements can be used as car headlights and light bulbs. Development for use as is underway. Since the LED element consumes less electric power, the battery load is reduced when used as a car headlight. In addition, since it has a long life, fluorescent lamps and light bulbs used indoors are being replaced by LED elements. These LED elements are being developed to obtain luminance and emission spectrum that satisfy user requirements.

  The above-mentioned characteristics such as luminance and emission spectrum are mainly determined by the compound semiconductor constituting the LED element. However, characteristics such as luminance and viewing angle are greatly affected by the package on which the LED element is mounted. For this reason, a light emitting diode package has attracted attention as a means for obtaining brightness and viewing angle desired by the user. As such a light emitting diode package, one mounted on a ceramic substrate has been conventionally used. An example is shown in FIG. This light emitting diode package is formed by laminating a first ceramic substrate 101 and a second ceramic substrate 102, and an LED mounting portion 104 for mounting an LED element 103 is formed on the first ceramic substrate 101. The LED element 103 is connected to the wiring layers 106a and 106b by a wire 105, and is configured to supply a driving current from the outside through these wiring layers. On the other hand, the cavity 107 that accommodates the LED element 103 is formed so as to penetrate the second ceramic substrate 102, and a metal layer 108 is formed on the inner peripheral surface of the through hole so that the luminous flux from the LED element 103 can be transmitted. Reflective form.

  For manufacturing the light emitting diode package, a green sheet lamination method can be employed. First, a metallized paste that becomes the LED mounting portion 104 and the wiring layer 106 is printed and applied to the ceramic green sheet that becomes the first ceramic substrate 101, and the cavity 107 is formed by punching the second ceramic substrate 102. A metallized paste that becomes the metal layer 108 is applied to the peripheral surface. Thereafter, the ceramic substrates 101 and 102 are bonded and sintered at a high temperature to obtain a sintered body. After the ceramic substrates 101 and 102 are integrated in this way to form the metal layer 108, the LED mounting portion 104, and the wiring layer 106, a nickel plating layer, a gold plating layer, or the like is applied to the metal layer 108 by a well-known electroless plating method, The light reflecting surface is formed by depositing by electrolytic plating.

However, since the cavity 107 is formed by punching the second ceramic substrate 102, the angle θ becomes a right angle, and there is a problem that the luminous flux from the LED element 103 is not easily emitted to the outside. As a result, the desired viewing angle and brightness are not necessarily obtained. Therefore, as described in Patent Document 1 below, the angle θ is 55 ° to 70 °, the center line average roughness Ra of the metal layer is 1 to 3 μm, and the light reflectance is 80% or more. Thus, a light emitting diode package with high reflection efficiency has been proposed. The embodiment is shown in FIG. In this light emitting diode package, a ceramic green sheet serving as the second ceramic substrate 102 is punched using a punching die or the like so that the angle θ is 55 ° to 70 °, and the metal layer 108 is formed on the inner peripheral surface of the through hole. Form. Since the light reflecting surface is formed so as to spread outward, it is easy to emit light to the outside.
Japanese Patent Laid-Open No. 2002-232017

  However, it is difficult to perforate the ceramic green sheet so that the angle θ is always a constant angle, and there is a problem that the angle θ varies when it is mass-produced. Further, when a metallized paste is applied to a ceramic green sheet and a metal layer is formed by simultaneous firing with ceramic, the surface is likely to be bent, and it is difficult to form a high-quality light reflecting surface. Therefore, there has been a problem that variations in luminance and viewing angle become large.

  On the other hand, in order to manufacture the light emitting diode package of FIGS. 7A and 7B, as described above, a process of laminating two ceramic green sheets is required. In the laminating step, a method is used in which an adhesive is applied to the ceramic green sheets and the pressure is applied while heating. The applicant has been developing a light-emitting diode package that can be manufactured more easily by omitting such a lamination process, and has been made for a long time by the present applicant.

  The present invention has been made in the background as described above. In particular, the present invention has a high-quality light reflecting surface for reflecting the emitted light beam from the LED element to the outside, is easy to manufacture, and has a brightness and a viewing angle. It is an object of the present invention to provide a light emitting diode package with small variations.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above-described problems, a light emitting diode package of the present invention has an LED element mounting region formed on a ceramic substrate, and a metal ring is disposed on the ceramic substrate along a path surrounding the LED element. A main feature is that a fillet portion made of an Ag-based brazing material is formed along the inner peripheral surface of the ring, and a light reflecting surface that reflects the luminous flux from the LED element in a predetermined direction is formed on the fillet portion. To do.

  In order to solve the above-described problem, the light emitting diode package of the present invention includes a fillet portion formed on a ceramic substrate so that the metallized layer is formed along the path and extends over the metallized layer and the inner peripheral surface of the ring. Is the main feature.

  Further, the ring is brazed to the metallized layer, and a fillet portion is formed so as to straddle the metallized layer formed inside the ring and the inner peripheral surface of the ring.

  The light emitting diode package further includes a sealing member for the LED element, and a sealing member accommodating portion that accommodates the sealing member is formed in the ring.

  Further, the sealing member also serves as a lens that refracts the luminous flux from the LED element in a predetermined direction.

  In the light emitting diode package of the present invention, an LED element mounting region is formed on a ceramic substrate, a metallized layer is formed on the ceramic substrate along a path surrounding the LED element, and a metal ring is formed on the metallized layer. It is brazed. The width of the metallized layer is made larger than the width of the ring, so that the metallized layer remains inside the brazed ring. And the fillet part which consists of Ag type brazing material is formed so that the metallization layer which exists inside a ring, and the internal peripheral surface of a ring may be straddled. Since the surface of the fillet portion is smooth, it can be used as a light reflecting surface for reflecting the luminous flux from the LED element in a predetermined direction.

  The above-mentioned fillet portion is formed so that particles of Ag brazing material are poured into the metallization layer and subjected to a high temperature treatment of about 800 ° C., for example, so that the particles melt and straddle the metallization layer and the inner peripheral surface of the ring. Can do. Since the brazing material reflows at a high temperature, a smooth light reflecting surface can be obtained, which is more suitable for a light emitting diode package than a light reflecting surface using a conventional metallized layer. As will be described later, the angle of the light reflecting surface can be easily adjusted. Here, the Ag-based brazing material refers to an alloy containing silver as a main component and a metal such as copper, zinc or cadmium added thereto.

  In the fillet structure, the angle formed by the light reflecting surface is an important parameter. In the prior art, as shown in FIG. 57b), the ceramic green sheet was punched at an angle, so the variation in the angle θ was large. On the other hand, in the present invention, since the manufacturing variation of the ring and the metallized layer is relatively small, the fillet portion can be formed with high accuracy, and as a result, the angle θ can be made constant.

  On the other hand, the light emitting diode package has a sealing member for sealing the LED element, and a sealing member accommodating portion for accommodating the sealing member is formed in the above-described ring. Since the sealing member is provided, it is possible to prevent the LED element or the fillet portion from being damaged due to water or the like entering the package. Further, a condensing surface may be formed on the surface of the sealing member so as to function as a lens.

  The ceramic substrate is preferably a square plate. The reason is that it is not necessary to laminate a number of ceramic green sheets when manufacturing a ceramic substrate with such a simple structure. In addition, a rectangular plate shape can make a large number of ceramic substrates at a time using a large size, and thus the manufacturing cost can be reduced.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1A is a cross-sectional view of a light emitting diode package, and FIG. 1B is a perspective view of the same. As shown in the figure, a mounting region 4 for the LED element 1 is formed on the surface of the ceramic substrate 2, and a metal ring 6 is disposed along a path surrounding the LED element 1. A fillet portion 5 is formed. In addition, a light reflecting surface 15 is formed on the fillet portion 5 to reflect the emitted light beam from the LED element to the outside.

  More specifically, a metallized layer 11 is formed along a path surrounding the LED element 1, and a ring 6 is brazed to the metallized layer 11. The width of the metallization 11 is thicker than that of the ring 6, and a metallization layer is present inside the ring. And the fillet part which consists of Ag type brazing material is formed so that the metallization layer inside a ring and the ring inner peripheral surface 14 may be straddled. On the other hand, the LED element 1 is connected to the internal electrodes 12 a and 12 b through the wire 3, and these internal electrodes are connected to the external electrodes 10 a and 10 b through the conduction path 9. And it is set as the form which supplies the drive current of the LED element 1 from the external electrodes 10a and 10b. The internal electrodes 12a and 12b, the metallized layer 11, and the like can be formed using a metal such as molybdenum, tungsten, silver, or copper.

  The ring 6 includes a housing portion 8 for the sealing member 7. The sealing member 7 is fixed to the accommodating portion 8 with an adhesive or the like. Such a sealing member 7 can be made of transparent resin or glass, but is preferably made of transparent resin. The reason is that the transparent resin is easy to process and can be easily manufactured even with a relatively small sealing member. As the transparent resin, for example, a methacrylic resin, a styrene resin, an acrylic resin, or the like can be suitably used. The sealing member 7 has a function of protecting the LED element 1 and the fillet portion 5 by preventing water and the like from entering. A curved surface may be formed on the sealing member 7 to provide a lens function, and the sealing member 7 may be used as auxiliary means for adjusting the angle of light. Although not shown, the inner side of the ring 6 may be covered with a transparent resin. That is, after a transparent resin such as methacrylic resin is heated to be in a fluid state, it is injected inside the ring 6 to seal the LED element 1, fillet portion 5, and internal electrodes 12 a and 12 b together with the wires 3. To do. In this way, it is not necessary to form the accommodating portion 8 of the sealing member 7 in the ring 6, so that the shape of the ring can be simplified. Moreover, since airtightness improves, the surface deterioration of the fillet part 5 can be prevented.

  When the cylindrical ring 6 is used as in the embodiment of FIG. 1, the circular fillet portion 5 can be formed, so that the light from the LED element 1 is uniformly reflected by the fillet portion 5 and is reflected without unevenness. Light can be emitted. Therefore, it is desirable to use the ring 6 having a substantially cylindrical shape.

  For the ceramic substrate 2, a ceramic such as alumina, AlN, SiC, or the like can be suitably used. As shown in the embodiment of FIG. 1, the light emitting diode package of the present invention uses a rectangular plate-shaped ceramic substrate. The ceramic substrate having such a simple shape can be a double plate in which a plurality of ceramic green sheets are stacked or a single plate that is not stacked, but is preferably a single plate. The reason is that, when the light emitting diode package is manufactured, if the ceramic green sheet laminating process can be omitted, the manufacturing process can be simplified and the cost can be reduced. Although not shown, another ceramic substrate may be laminated on the external electrodes 10a and 10b, and the external electrode may be drawn from the side surface of the ceramic substrate. In the case of such a form, a lamination process is required.

  FIG. 2 is an enlarged view of the fillet portion. As shown in the figure, the angle θ formed by the light reflecting surface is determined by the height A from the bottom surface of the ring to the sealing member 7 and the width B of the metallized layer existing inside the ring 6. In the present invention, by setting the angle θ to 30 ° to 60 °, the efficiency of reflecting light to the outside can be maximized. The angle θ can be easily changed by adjusting the height A of the ring and the width B of the metallized layer. That is, it is convenient when it is necessary to change the angle θ. On the other hand, the accuracy of the angle θ is determined by manufacturing variations of A and B. In the present invention, since the ring is made of metal, the processing accuracy is good. The width B is determined by the alignment accuracy when brazing the ring. If this alignment is performed with high accuracy, the accuracy of the angle θ can be improved, and as a result, the light from the LED element can be reflected at a constant angle. Further, the light reflection surface 15 can be plated to further increase the light reflectivity. This plating is preferably a metal that is white like silver plating and does not color the light from the LED element.

  The light emitting diode package can be mounted with a plurality of light emitting diodes as shown in FIG. In the figure, LED elements corresponding to red, blue, and green wavelengths are mounted, and white light with high luminance is obtained by combining these three types. Each LED element 1 is connected to a common terminal 16 and an internal electrode 12, and three internal electrodes 12 are formed so that a voltage can be separately applied to each LED element. The LED elements can be connected in series or in parallel. There is also a method in which a limited space is effectively used by forming one + and one negative electrode without forming a plurality of internal electrodes.

  A method for manufacturing a light emitting diode package according to the present invention will be described below with reference to FIGS. First, as shown in FIG. 4, a plate-shaped ceramic green sheet 2 'is prepared (step 1). Such a ceramic green sheet 2 'can be obtained by making a mixed slip of ceramic fine powder and organic binder, plasticizer, solvent, etc. into a thin plate shape by a well-known doctor blade method or calendar method. As the ceramic, for example, alumina, AlN, SiC, or the like is preferably used.

  Thereafter, a through-hole 9 'is formed in the ceramic green sheet 2' (step 2). The through hole 9 ′ is formed by punching the ceramic green sheet 2 ′ using a punching die or the like. Then, a metallized paste is printed and applied to a predetermined position on the surface of the green sheet and the through hole 9 '(step 3). A known screen printing method is used for printing on the surface, and a method of printing while sucking from the opposite side of the printing surface is used for applying to the through hole 9 ′. For the metallized paste, for example, metal powder such as molybdenum, tungsten, silver, or copper is used as a material. After printing the metallized paste as described above, the ceramic green sheet 2 'is fired at a high temperature together with the metallized paste. As a result, the ceramic substrate 2 is obtained, and the LED element mounting region 4, the metallized layer 11, the internal electrodes 12a and 12b, the external electrodes 10a and 10b, and the conduction path 9 can be formed on the surface.

  Next, the ring 6 is brazed to the metallized layer 11 using the brazing material 13 (step 4). For example, Kovar can be suitably used as the material of the ring 6. Any brazing material 13 may be used as long as it has sufficient adhesive strength. For example, an Ag-based brazing material can be used. After brazing the ring 6, Ag-based brazing particles 5 'are placed on the metallized layer 11 (step 5). Thereafter, for example, when a high temperature treatment of about 800 ° C. is performed, the particles 5 ′ are melted to form the fillet portion 5 (step 6). A light reflecting surface 15 is formed on the completed fillet portion. Even if it is as it is, it is excellent in the reflection efficiency of light, but if the Ag plating (not shown) is applied, the reflection efficiency can be further increased. After step 6, the LED element 1 is mounted and wire-bonded to the internal electrode. And if the sealing member 7 is accommodated in the accommodating part 8, it will become the light emitting diode package shown in FIG.

  In the present invention, since the metal ring 6 is used, the fillet portion 5 can be easily formed because it is well suited to the Ag-based brazing material. Here, as shown in FIG. 6A, if a similar effect is obtained by laminating the three ceramic substrates 2a, 2b, and 2c, a step of forming through holes in the ceramic substrates 2b and 2c; Three extra steps are required: a step of printing and applying the metallized layer 11a on the inner peripheral surface of the through hole, and a step of laminating these ceramic substrates. In addition, since the processing accuracy of ceramic is not so good, the variation of the through hole becomes large, and as a result, the shape of the fillet portion also has a large variation. In contrast, the present invention is a relatively simple manufacturing method in which a metal ring is brazed to a plate-like ceramic substrate to form a fillet portion, but the ring processing accuracy is good, so the accuracy of the fillet portion is improved. As a result, variations in luminance and viewing angle can be reduced. On the other hand, as shown in FIG. 6B, an angle can be given to the inner peripheral surface of the ring, and this inner peripheral surface can be used as a light reflecting surface. Is difficult. Especially in the case of small light emitting diode packages, it is difficult to manufacture such shaped rings.

The (a) sectional view and (b) perspective view which show one Embodiment of a light emitting diode package. The expanded sectional view of a fillet part. The perspective view of the light emitting diode package carrying a some LED element. An example of the manufacturing method of a light emitting diode package. The figure following FIG. Temporarily, (a) When a ceramic substrate is laminated | stacked instead of a metal ring, (b) Sectional drawing at the time of attaching an inclined surface to a ring. Sectional drawing of the conventional light emitting diode package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED element 2 Ceramic substrate 3 Wire 4 Mounting area | region of LED element 5 Fillet part 6 Metal ring 7 Sealing member (lens)
8 Sealing member accommodating portion 9 Conducting path 14 Ring inner peripheral surface 15 Light reflecting surface

Claims (1)

  An LED element mounting region is formed on the ceramic substrate, and a metal ring is disposed on the ceramic substrate along a path surrounding the LED element, and an Ag brazing material is formed along the inner peripheral surface of the ring. The light emitting diode package is characterized in that a light reflecting surface for reflecting the luminous flux from the LED element in a predetermined direction is formed on the fillet portion.

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