JP2005347312A - Package for light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package for a light emitting device wherein an emitted light tends to direct in a fixed direction. <P>SOLUTION: The package comprises a ceramic board having a main surface and a rear surface, and a frame like a plate that has a main front surface and a main rear surface as well as an inner circumferential surface formed by a through hole penetrating the main front and rear surfaces. The frame is arranged on the main surface of the ceramic board while the main rear surface is in contact with the main surface. Thus, the side of the main front surface is open in the through hole. The mounting part of the light emitting device is formed on the main surface surrounded by the inner circumferential surface of the through hole, and a light reflection layer formed of a metallic layer is formed on the inner circumferential surface, which is inclined smaller in the opening direction. As a result, the opening is small, so that a light emitted from the opening tends to direct in a fixed direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting element package for housing a light emitting element such as a light emission diode (LED element).

  Conventionally, a ceramic substrate has been used as a package of a light emitting diode (LED element) which is one of the light emitting elements. An example is shown in FIG. This light emitting element package is formed by laminating a ceramic window frame 102 on a ceramic substrate 101, and an LED mounting portion 104 for mounting the LED element 103 is formed on the 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 for accommodating the LED element 103 is formed so as to penetrate the ceramic window frame 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 is transmitted to the outside. Reflect to.

  The light emitting element package is manufactured as follows, for example. First, on the ceramic green sheet that becomes the ceramic substrate 101, the metalized paste that becomes the LED mounting portion 104 and the wiring layers 106 a and 106 b is printed, and the ceramic window frame 102 is punched to form the cavity 107, and the inner peripheral surface of the through hole A metallized paste that becomes the metal layer 108 is printed on the substrate. Then, the ceramic substrate 101 and the ceramic window frame 102 are bonded and sintered at a high temperature to obtain a sintered body in which these are integrated. Thereafter, a metal plating layer of nickel, gold, palladium, platinum or the like is formed on the metal layer 108 or the wiring layers 106a and 106b.

However, since the cavity 107 is formed by punching the ceramic window frame 102, the angle θ becomes a right angle, and there is a problem that the emitted light flux from the LED element 103 is difficult to be emitted to the outside. Therefore, it is difficult to obtain a desired viewing angle and luminance. Therefore, in the following Patent Document 1, by drilling so that 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. A package for a light emitting device capable of obtaining high reflection efficiency has been proposed. The embodiment is shown in FIG. This light emitting element package is punched into a ceramic green sheet to be a ceramic window frame 102 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 reflection layer made of the metal layer 108 is formed so as to spread outward, it is easy to emit light to the outside.
Japanese Patent Laid-Open No. 2002-232017

  However, the conventional light emitting device package has a problem that emitted light is difficult to be directed in a certain direction (poor directivity).

  The present invention has been made in the background as described above. In particular, it is an object of the present invention to provide a package for a light emitting element in which emitted light tends to be directed in a certain direction.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, a package for a light-emitting element of the present invention has a ceramic substrate having a substrate main surface and a substrate back surface, is plate-shaped, has a main surface and a main back surface, the main surface and the main back surface, The frame is disposed on the main surface of the ceramic substrate so that the main back surface is in contact with the main surface of the substrate, and the through hole is The main surface side is opened, a light emitting element mounting portion is formed on the main surface of the substrate surrounded by the inner peripheral surface of the through hole, and a light reflecting layer composed of a metal layer is formed on the inner peripheral surface. The main feature is that the inner peripheral surface is inclined so as to become narrower in the opening direction.

  The light emitting device package of the present invention includes a ceramic substrate having a substrate main surface and a substrate back surface, and a frame. This frame is made of ceramic or metal, has a plate shape, has a main surface and a main back surface, and has an inner peripheral surface formed by a through-hole penetrating the main surface and the main back surface. The frame is disposed on the ceramic substrate, and the main back surface is in contact with the main surface of the ceramic substrate. Thereby, the main surface side of the frame is opened, and a cavity having the bottom surface of the main surface of the ceramic substrate is formed. A mounting portion of the light emitting element is formed on the main surface of the substrate (the bottom surface of the cavity) surrounded by the inner peripheral surface of the through hole. In addition, a light reflection layer formed of a metal layer is formed on the inner peripheral surface of the through hole. Furthermore, the inner peripheral surface of the through hole is inclined so as to become narrower in the opening direction. As a result, the opening is narrowed, so that light emitted from the opening is easily directed in a certain direction. Part of the light emitted from the light emitting element strikes the light reflecting layer, is reflected, is reflected again by the metal layer (light emitting element mounting portion or electrode) formed on the bottom surface of the cavity, and is emitted from the opening.

  The light reflecting layer can be formed using a metallized layer (metal layer). Alternatively, a metal plating layer such as Ni, gold, palladium, or platinum may be formed on the surface of the metallized layer, and this metal layer may be used as a light reflecting layer.

  Another embodiment of the light emitting device package of the present invention is a ceramic substrate having a substrate main surface and a substrate back surface, plate-shaped, having a main surface and a main back surface, and the main surface and the main back surface. The metal frame is disposed on the ceramic substrate so that the main back surface is in contact with the substrate main surface. A main surface side is opened, and a mounting portion of a light emitting element is formed on the main surface of the substrate surrounded by the inner peripheral surface of the through hole, and the inner peripheral surface reflects a luminous flux from the light emitting element, and The peripheral surface is inclined so as to become narrower in the opening direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1A shows a cross-sectional view of a light emitting device package according to the present invention, and FIG. This light emitting device package is composed of a ceramic substrate 2 having a substrate main surface and a substrate back surface, and a ceramic frame 3 having a plate shape and having a main surface and a main back surface. An inner peripheral surface 9 is formed in the ceramic frame 3 by a through hole penetrating the main surface and the main back surface. Then, the ceramic frame 3 is arranged on the ceramic substrate 2 so that the back side is in contact with the main surface of the substrate. As a result, a cavity C having an opening on the main surface side and a bottom surface on the main surface of the substrate is formed. A mounting portion 4 of the LED element 1 and internal electrodes 7a and 7b are formed on the main surface of the substrate surrounded by the inner peripheral surface 9 (the bottom surface of the cavity C). A light reflecting layer RP composed of a metallized layer (metal layer) 5 is formed on the inner peripheral surface 9, and the inner peripheral surface 9 is inclined so as to become narrower in the opening direction. As a result, the opening is narrowed, so that light emitted from the opening is likely to be directed in a certain direction. Further, part of the light reflected by the light reflecting layer is further reflected by the mounting portion 4 and the internal electrodes 7a and 7b of the light emitting element 1 and emitted from the opening.

  The angle θ formed between the inner peripheral surface 9 and the main surface of the substrate is preferably 30 ° to 80 °. It is difficult to make the inclination angle less than 30 °, and when it exceeds 80 °, the directivity of light is not necessarily improved sufficiently. The more desirable angle θ is 40 ° to 70 °, and more desirably 50 ° to 60 °.

  On the other hand, the internal electrodes 7 a and 7 b formed on the bottom surface of the cavity C are electrically connected to the external electrode 8 a through the via 6. The LED element 1 and the internal electrodes 7a and 7b are connected by a wire 10, and the drive current of the LED element 1 is supplied from the external electrodes 8a and 8b.

  The metallized layer (metal layer) 5 may be coated with a metal plating such as Ni, gold, palladium, or silver by electrolytic plating or electroless plating, and the metal layer may be used as the light reflecting layer RP.

  Next, FIG. 2 will be described. FIG. 2A shows an embodiment using a metal frame 11. The metal frame 11 has a plate shape like the ceramic frame 3 of FIG. 1 and has a main surface and a main back surface, and an inner peripheral surface 9 is formed by a through-hole penetrating the main surface and the main back surface. The metal frame 11 is bonded to the ceramic substrate 2 using an adhesive layer (not shown) such as a brazing material. A light reflecting layer RP made of a metallized layer (metal layer 5) is formed on the inner peripheral surface 9.

  In a ceramic frame, a through hole is formed by punching the ceramic green sheet at an angle θ. Therefore, it is difficult to make the inner peripheral surface 9 an arbitrary curved surface. On the other hand, when a metal frame is used, a desired shape can be obtained. For example, as shown in FIG. 2B, the through hole can be formed in a dome shape. If it does in this way, it will become easy to concentrate the light reflected on the light reflection layer RP in the mounting part 4 of the LED element 1. FIG. As a result, the light is reflected again by the mounting portion 4 and is easily emitted from the opening.

  Moreover, in another embodiment, as shown in FIG.2 (c), the inner peripheral surface 9 of a through-hole can reflect light. Since a metal frame is used in FIG. 2C, the luminous flux from the LED element 1 can be reflected without forming a metallized layer (metal layer) on the inner peripheral surface 9.

  In the embodiment of FIG. 1 or FIG. 2, only one LED element is mounted, but a plurality of LED elements may be mounted. The cavity C may be sealed with a transparent polymer material such as an epoxy resin.

  A method for manufacturing the light emitting device package of FIG. 1 will be described below with reference to the process chart of FIG. First, ceramic green sheets 2 'and 3' to be the ceramic substrate 2 and the ceramic frame 3 are prepared (step 1). Such a ceramic green sheet can be obtained by making a mixed slip of ceramic fine powder and an organic binder, a plasticizer, a solvent, etc. into a thin plate by a well-known doctor blade method or calendar method. For example, alumina, AlN, SiC, or the like is used as the ceramic material.

  Next, the through hole h to be the via 6 is punched in the ceramic green sheet 2 'using a punching die, and the through hole P is punched and formed in the ceramic green sheet 3' (step 2). The angle θ is, for example, 30 ° to 80 °.

  After forming the through hole h and the through hole P in this way, a metallized paste made of metal powder such as W, Mo, copper, silver or the like is printed on the inner peripheral surface of the through hole P, and the ceramic green sheet 2 ′ is printed. Also, the metallized pastes 4 ′, 7a ′, 7b ′, 8a ′, 8b ′ are printed at predetermined positions (step 3). A known screen printing 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 printing the through hole h.

  Next, the ceramic green sheets 2 ′ and 3 ′ are bonded so that the inner peripheral surface of the through hole P becomes narrower in the opening direction. For this bonding, a method is used in which an adhesive is applied to the bonding surfaces of the ceramic green sheets 2 ′ and 3 ′ and pressure bonding is performed while heating. Thereafter, when the bonded green sheets 2 ′ and 3 ′ are fired at a high temperature together with the metallized paste, a sintered body in which these are integrated is obtained, and the metallized paste is subjected to a high-temperature treatment so that the metallized layer 5, the LED mounting portion 4, the inside Electrodes 7a and 7b, vias 6, and external electrodes 8a and 8b are formed. The ceramic green sheet is fired to form a ceramic substrate 2 and a ceramic frame 3. After this step, when the LED element 1 is mounted, the light emitting element package of FIG. 1 is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS (a) Sectional drawing (b) perspective view which shows one Embodiment of the package for light emitting elements of this invention. Embodiment different from FIG. FIG. 2 is a process diagram showing a method for manufacturing the light emitting device package of FIG. Conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED element 2 Ceramic substrate 3 Ceramic frame 4 LED mounting part 5 Metallized layer (metal layer)
6 Via 7a, 7b Internal electrode 8a, 8b External electrode 11 Metal frame

Claims (2)

A ceramic substrate having a substrate main surface and a substrate back surface;
It is plate-shaped, has a main surface and a main back surface, and is composed of a frame having an inner peripheral surface formed by a through-hole penetrating the main surface and the main back surface,
The frame is arranged on the substrate main surface of the ceramic substrate so that the main back surface is in contact with the substrate main surface, and the through hole is opened on the main surface side,
A light emitting element mounting portion is formed on the substrate main surface surrounded by the inner peripheral surface of the through hole,
A light reflecting layer composed of a metal layer is formed on the inner peripheral surface,
A package for a light emitting element, wherein the inner peripheral surface is inclined so as to become narrower in an opening direction. A ceramic substrate having a substrate main surface and a substrate back surface;
It is plate-shaped, has a main surface and a main back surface, and is composed of a metal frame having an inner peripheral surface formed by a through hole penetrating the main surface and the main back surface,
The metal frame is disposed on the ceramic substrate so that the main back surface is in contact with the substrate main surface, and the through hole is open on the main surface side,
A light emitting element mounting portion is formed on the substrate main surface surrounded by the inner peripheral surface of the through hole,
The inner peripheral surface reflects the luminous flux from the light emitting element;
A package for a light emitting element, wherein the inner peripheral surface is inclined so as to become narrower in an opening direction.

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