JP4574694B2 - Light emitting element storage package and light emitting device - Google Patents

Description

  The present invention relates to a light-emitting element storage package and a light-emitting device for storing a light-emitting element, which are used in a display device using a light-emitting element such as a light-emitting diode.

  Conventionally, light-emitting elements such as light-emitting diodes have been widely used in display devices such as an electric display panel due to the improvement in luminance. An example of a conventional light emitting element storage package (hereinafter also referred to as a package) is shown in FIG. As shown in the figure, a plurality of vertical and horizontal concave portions 14 are arranged on the surface of an insulating base 11 made of an aluminum oxide sintered body (alumina ceramic) or the like, and the mounting portion 12 and the wiring layer 15 are arranged in the concave portion 14. The light emitting element 13 is accommodated in the recessed portion 14 of the formed package and mounted on the mounting portion 12 and is electrically connected to the wiring layer 15 via the bonding wire 16 to constitute a display device. Characters and images can be displayed by applying electric power to the light emitting element 13 accommodated in the recess 14 of the package and causing the predetermined light emitting element 13 to emit light.

Further, in order to prevent light emitted from the light emitting element 13 from being transmitted through the insulating substrate 11 and mixed with light emitted from the light emitting element 13 accommodated in the adjacent concave portion 14, the inner surface of the concave portion 14 is made of tungsten or the like. A metal layer 17 made of a metallized layer or the like is formed. In addition, in order to efficiently reflect the light emitted from the light emitting element 13 and emit it to the outside, a metal layer having a high reflectance may be deposited on the surface of the metal layer 17.
JP-A-5-335627

  However, recently, the number of light emitting elements 13 per unit area of the package has been greatly increased in order to improve the resolution and definition of characters and images to be displayed, so that a large number of recesses 14 are formed. It has become to. For this reason, in the case of a display device in which a large number of light emitting elements 13 are housed in a package, some light emitting elements 13 continue to emit light when operated by causing the many light emitting elements 13 to emit light, and the light emission continues to be emitted. The temperature of the element 13 rises to near 90 ° C., and the temperature of the entire display device rises to near 60 ° C. While repeated thermal expansion and contraction due to such temperature increase and temperature decrease, cracks and cracks are generated and structurally deteriorated, particularly in locations where the internal stresses at the four corners of the insulating base 11 tend to concentrate. The light emitting element 13 also has a problem that an electric signal malfunctions or the light emitting element 13 is damaged, resulting in a shortened life of the display device.

  Further, the metal layer 17 deposited on the inner surface of the recess 14 is peeled off by the heat generated by the light emitting element 13, and the light emitted from the light emitting element 13 is mixed with the light emitted from the light emitting element 13 accommodated in the adjacent recess 14. However, there is a problem that it becomes impossible to radiate efficiently toward the outside.

  Accordingly, the present invention has been completed in view of the above-described conventional problems, and its purpose is to use it for a long period of time by efficiently dissipating the heat generated by the light emitting element by enhancing the heat dissipation effect of the insulating base. It is an object of the present invention to provide a light-emitting element storage package and a light-emitting device.

The light-emitting element storage package of the present invention is a light-emitting element storage package in which a plurality of recesses for storing light-emitting elements are arranged vertically and horizontally on an upper surface of an insulating base, and the upper and lower surfaces of the insulating base are Grooves are provided in the portions between the recesses, the grooves on the upper surface are arranged in parallel to each other, and the grooves on the lower surface are arranged in parallel to each other in a direction different from the grooves on the upper surface, The groove on the lower surface and the groove on the lower surface are characterized in that a light blocking layer for blocking light emitted from the light emitting element is applied between the concave portions adjacent to the inner surface .

The light emitting element storage package of the present invention is preferably characterized in that the groove on the upper surface and the groove on the lower surface are orthogonal to each other as seen in a plan view. Further, it is preferable that the insulating base has a through-hole penetrating from the upper surface to the lower surface at a portion where the groove on the upper surface and the groove on the lower surface intersect.

The light emitting device of the present invention is characterized in that it comprises a light-emitting element storing package of the present invention, a light emitting element housed in each of the plurality of recesses, and a transparent resin covering the light emitting element .

  In the light emitting element storage package of the present invention, air passes through the groove formed on the upper surface or the lower surface of the insulating base, and the heat dissipation effect of the insulating base is enhanced, so that the heat generated by the light emitting element can be efficiently dissipated. The metal layer deposited on the inner surface of the recess can be effectively prevented from peeling off. Therefore, a light-emitting element storage package and a light-emitting device that can be used for a long time can be obtained.

Further, since the light blocking layer for blocking light emitted in the light emitting element between the recess adjacent to the inner surface of the groove is adhered, the light emitting device an insulating substrate having a thickness thinned by forming a trench light Even if a part of the light can be transmitted, the light transmitted through the insulating substrate is blocked or reflected by the light blocking layer, so that light loss due to transmission through the insulating substrate can be prevented. It can radiate to the outside efficiently. In addition, it is possible to prevent light from adjacent light emitting elements from being mixed in color.

  The light emitting device of the present invention has high heat dissipation and high reliability that prevents the metal layer from peeling off.

  The light emitting element storage package of the present invention will be described in detail below. FIG. 1 is a cross-sectional view of an essential part showing an example of an embodiment of the package of the present invention, and FIG. 2 is a plan view of the package of FIG. In these drawings, 1 is an insulating substrate, 2 is a mounting portion, 3 is a light emitting element, 4 is a recess for housing the light emitting element 3, and a package mainly comprises these.

  In the package of the present invention, a plurality of recesses 4 for accommodating the light emitting elements 3 are arranged vertically and horizontally on the upper surface of the insulating substrate 1, and the periphery of each recess 4 on the upper surface or the lower surface of the insulating substrate 1. A groove 8 is formed along the outer periphery of the concave portion 4 at the portion.

The insulating substrate 1 of the present invention is composed of a sintered body (ceramics) such as an aluminum oxide sintered body (alumina ceramics), a mullite sintered body, and an aluminum nitride sintered body. In the case of consisting of raw material powders such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), and magnesia (MgO), an appropriate organic solvent and solvent are added and mixed to form a slurry. A ceramic green sheet (ceramic raw sheet, hereinafter also referred to as a green sheet) is obtained by forming into a sheet shape by a blade method or a calendar roll method, and then a through hole for the recess 4 is punched into the green sheet. A plurality of green sheets for forming the light emitting element 3 and green sheets having through holes for the recesses 4 are stacked. And it is manufactured by firing at a high temperature (about 1600 ° C.).

  A mounting portion 2 made of a conductor layer for mounting the light emitting element 3 is formed on the bottom surface of the concave portion 4. The mounting portion 2 is made of tungsten (W), molybdenum (Mo), copper (Cu), silver ( It consists of a metallized layer of metal powder such as Ag).

  The insulating base 1 has a pair of wiring layers 5a and 5b formed from the mounting portion 2 and its periphery to the outside of the insulating base 1 so as to be deposited. The wiring layers 5a and 5b are made of a metallized layer of a metal powder such as W or Mo, and are conductive paths for electrically connecting the light emitting element 3 accommodated in the recess 4 to the outside. A light emitting element 3 such as a light emitting diode (LED) or a semiconductor laser (LD) is fixed to the mounting portion 2 with a conductive bonding material such as gold (Au) -silicon (Si) alloy or Ag-epoxy resin. The electrodes of the light emitting element 3 are electrically connected to the wiring layer 5b through bonding wires 6. Then, the wiring layers 5a and 5b on the lower surface of the insulating base 1 are connected to the wiring conductors of the external electric circuit board so as to be electrically connected to each electrode of the light emitting element 3, and power and driving signals are supplied to the light emitting element 3. The The light emitting element 3 may be connected to the mounting portion 2 and the wiring layer 5b by flip chip mounting.

  The wiring layers 5a and 5b are made of a high melting point metal powder such as tungsten, molybdenum, or manganese, for example. For example, a green sheet serving as an insulating substrate 1 is made of a metal paste obtained by adding and mixing an appropriate organic solvent and solvent to the tungsten powder. In addition, a predetermined pattern is printed and applied in advance by a screen printing method, whereby the insulating substrate 1 is deposited on a predetermined position.

  It should be noted that a metal having excellent corrosion resistance such as nickel (Ni), gold (Au), Ag or the like is deposited on the exposed surfaces of the wiring layers 5a and 5b and the mounting portion 2 in a thickness of about 1 to 20 μm. The wiring layers 5a and 5b and the mounting portion 2 can be effectively prevented from being oxidized and corroded, and the mounting portion 2 and the light emitting element 3 are fixed and the wiring layer 5b and the bonding wire 6 are connected, and the wiring layers 5a and 5b. And the wiring conductor of the external electric circuit board can be strengthened. Therefore, on the exposed surfaces of the wiring layers 5a and 5b and the mounting portion 2, an Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer or an Ag plating layer having a thickness of about 0.1 to 3 μm are electroplated. It is more preferable that the electrodes are sequentially deposited by electroless plating.

  Further, the inner surface of the concave portion 4 of the insulating base 1 prevents light emitted from the light emitting element 3 from leaking into the adjacent concave portion 4 to cause bleeding in characters and images displayed as a display device. In order to reflect the light emitted from the light emitting element 3 on the inner surface of the recess 4 and to obtain a good display device, the metal layer 7 is preferably formed by deposition. The metal layer 7 is made of a metallized layer such as tungsten or molybdenum-manganese. The green sheet is preliminarily printed and applied by screen printing or the like, thereby being deposited on the inner surface of the recess 4 of the insulating substrate 1.

  The metal layer 7 is preferably coated with a metal that easily reflects light on its surface by plating or the like. In this case, the light emitted from the light emitting element 3 is reflected by the metal layer 7 and efficiently radiated to the outside. Therefore, when the light emitting element 3 emits light and is operated as a display device, displayed characters and images can be made extremely clear. For this reason, it is preferable to deposit a metal having a reflectance of 80% or more on the surface of the metal layer 7. Examples of such metals include Ni, Au, Ag, and the like. By depositing these metals, the reflectance of the light emitted from the light emitting element 3 can be 80% or more. When the reflectance with respect to the light emitted from the light emitting element 3 is less than 80%, it becomes difficult to favorably reflect the light emitted from the light emitting element 3 accommodated in the recess 4.

  Alternatively, the metal layer 7 may be a layer on which a highly reflective metal such as Ni, Au, or Ag is deposited.

  Moreover, it is preferable that the inner surface of the recess 4 is an inclined surface and extends outward from the bottom surface of the recess 4 at an angle of 35 to 70 ° with respect to the upper surface of the insulating substrate 1. When the angle θ exceeds 70 °, it tends to be difficult to favorably reflect the light emitted from the light emitting element 3 accommodated in the recess 4 to the outside. On the other hand, when the angle θ is less than 35 °, it tends to be difficult to stably and efficiently form the inner surface of the concave portion 2 at such an angle, and the concave portion 4 is enlarged, and the adjacent concave portion 4 is not enlarged. Since the interval is wide, the resolution of characters and images displayed as the light emitting device is lowered and cannot be made clear.

  The arithmetic average roughness Ra of the surface of the metal layer 7 on the inner surface of the recess 4 is preferably 1 to 3 μm. If it is less than 1 μm, it becomes difficult to uniformly reflect the light emitted by the light emitting element 3 accommodated in the recess 4, and the intensity of the reflected light tends to be biased. If it exceeds 3 μm, the light emitted from the light emitting element 3 accommodated in the recess 4 is scattered, and it becomes difficult to uniformly radiate the reflected light to the outside with a high reflectance.

  Moreover, it is preferable that the cross-sectional shape of the recessed part 4 is circular. In this case, there is an advantage that the light emitted from the light emitting element 3 accommodated in the concave portion 4 can be uniformly reflected by the metal layer 7 on the inner surface of the concave portion 4 in all directions and radiated to the outside very uniformly.

  And in this invention, the groove | channel 8 is formed in the site | part around the recessed part 4 of each upper surface or lower surface of the insulation base | substrate 1 along the outer periphery of the recessed part 4. FIG. When air passes through the groove 8, heat generated by the light emitting element 3 accommodated in the recess 4 can be dissipated well, and the metal layer 7 can be effectively prevented from peeling off in the recess 4. it can. Therefore, the package can be used as a light emitting device over a long period of time.

  Such a groove | channel 8 can be provided by forming the through-hole used as the groove | channel 8 in the one part green sheet used as the insulation base | substrate 1. FIG. Further, there is a method in which a groove 8 is formed by cutting a green sheet laminate formed by laminating a plurality of green sheets using a cutter blade or the like.

  Further, by forming irregularities with a height less than ½ of the groove width on the inner surface of the groove 8, the surface area of the inner surface of the groove 8 can be increased and the heat dissipation effect can be enhanced. When the height of the unevenness is made larger than ½ of the groove width, air becomes difficult to pass through the groove. Such a groove 8 having irregularities formed on the inner surface can be formed by laminating a plurality of green sheets having different groove widths, or by pressing the green sheet from the outside with a concavo-convex mold or the like.

  3 and 4 show another example of the embodiment of the present invention. As shown in these drawings, the direction and length in which the grooves 8 are formed are not particularly limited. However, when the recess 4 has a quadrangular cross-sectional shape, the recesses 4 face each other as shown in FIG. The grooves 8 may be formed along a pair of sides. Further, as shown in FIG. 5, grooves 8 extending along a pair of opposing sides of the recess 4 and extending over the plurality of recesses 4 may be formed.

  FIG. 5 is a cross-sectional view of the package of the present invention in a direction crossing the groove 8 on the lower surface of the insulating base 1. In the present invention, as shown in plan views in FIGS. 6 and 7, grooves 8 are formed on the upper and lower surfaces of the insulating base 1, and grooves are respectively formed in the portions between the recesses 4 on the upper and lower surfaces of the insulating base 1. 8, the grooves 8 on the upper surface are arranged in parallel to each other, and the grooves 8 on the lower surface are arranged in parallel to each other in a direction different from the grooves 8 on the upper surface.

  Further, as shown in a plan view in FIG. 8, the insulating substrate 1 may penetrate from the upper surface to the lower surface at a portion where the groove 8 on the upper surface of the insulating substrate 1 intersects with the groove 8 on the lower surface. In this case, it is necessary to form the groove 8 so that the wiring layers 5a and 5b are not blocked.

  Further, as shown in FIG. 9, it is preferable that a light blocking layer 9 that blocks light emitted from the light emitting element 3 is applied between the recesses 4 adjacent to the inner surface of the groove 8. In this case, the light blocking layer 9 is disposed so as to overlap at least the region R2 where the insulating base 1 is exposed between the mounting portion 2 on the bottom surface of the recess 4 and the wiring layers 5a and 5b and the metal layer 7 on the inner surface of the recess 4. Has been. As a result, part of the light that has entered and transmitted from the region R2 to the insulating substrate 1 is blocked or reflected by the light blocking layer 9 that covers the region R2, and the light can be prevented from leaking outside from the insulating substrate 1. .

  In this case, the light that enters the insulating base 1 from the region R2 also has a component in a direction (oblique direction) that is not orthogonal to the side surface of the concave portion 4, and therefore the region R1 on the side surface of the concave portion 4 where the insulating base 1 is not exposed. By covering with the light blocking layer 9, light in an oblique direction can be blocked or reflected. Thus, the light blocking layer 9 is preferably applied to a wide area, and can effectively prevent the light in the oblique direction from being blocked or reflected and leaked to the outside.

  The light blocking layer 9 is made of a metal powder such as tungsten, molybdenum, manganese, copper, or silver, for example, and a green sheet that serves as an insulating substrate 1 is made of a metal paste obtained by adding and mixing an appropriate organic solvent and solvent to the tungsten powder. The inner surface of the groove 8 is preliminarily printed and applied in a predetermined pattern by a screen printing method, so that it is deposited and formed at a predetermined position on the insulating substrate 1 with a thickness of about 5 to 30 μm.

  The light blocking layer 9 is preferably coated with a metal having excellent corrosion resistance, such as Ni, Au, Ag, etc. on its surface in a thickness of about 1 to 20 μm, and it is effective that the light blocking layer 9 is oxidized and corroded. In addition, it is possible to satisfactorily block or reflect light that has entered from the region R2 where the inner surface of the recess 4 is exposed and has passed through the insulating substrate 1, and can effectively prevent light from leaking to the outside. Therefore, on the surface of the light shielding layer 9, an Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer or an Ag plating layer having a thickness of about 0.1 to 3 μm are electroplating or electroless plating. It is more preferable that the layers are sequentially deposited.

  The light blocking layer 9 may be a metal layer made of tungsten, molybdenum, manganese, copper, silver, aluminum or the like by vapor deposition or the like. Further, instead of the metallized layer, it may be made of a dark resin paste containing a dye or pigment such as black, and the light that penetrates from the region R2 where the inner surface of the recess 4 is exposed and passes through the insulating substrate 1 is improved. Can be absorbed and blocked. Furthermore, a plate-like or box-like metal member that covers the inner surface of the groove 8 may be mounted in the groove 8. The light blocking layer 9 may be made of a material having a high heat dissipation effect such as an alloy of Cu-W, or may have a higher heat dissipation effect by forming irregularities on the surface.

  In addition, as shown in FIG. 10, the groove 8 may be formed from the lower surface of the insulating substrate 1 to the side of R2, and the light blocking layer 9 may be applied to the inner surface.

  Further, the light blocking layer 9 may be formed also on the inner surface of the concave portion 4 and the portion of the upper surface of the insulating substrate 1 where the groove 8 is not formed.

  Thus, in the package of the present invention, a plurality of recesses 4 for accommodating the light emitting elements 3 are arranged vertically and horizontally on the upper surface of the insulating substrate 1, and the respective recesses 4 on the upper surface or the lower surface of the insulating substrate 1 are arranged. Since the groove 8 is formed along the outer periphery of the concave portion 4 in the area around the substrate, air passes through the groove 8 of the insulating base 1, efficiently dissipating heat generated by the light emitting element 3, and the insulating base. 1 can be enhanced, and the metal layer 7 deposited on the inner surface of the recess 4 can be effectively prevented from peeling off. Therefore, the package can be used as a display device for a long time.

  In the package of the present invention, the groove 8 forms the groove 8 when the light blocking layer 9 for blocking the light emitted from the light emitting element 3 is applied between the recesses 4 adjacent to the inner surface thereof. Even if part of the light of the light emitting element 3 can pass through the insulating substrate 1 having a reduced thickness, the light transmitted through the insulating substrate 1 is blocked or reflected by the light blocking layer 9. Therefore, light loss due to transmission through the insulating substrate 1 can be prevented and light can be efficiently emitted to the outside. In addition, it is possible to prevent light from adjacent light emitting elements from being mixed in color.

  Further, in the package of the present invention, the light emitting element 3 is attached to the bottom surface of the recess 4 of the insulating substrate 1 via a conductive adhesive, and one electrode (lower surface electrode) of the light emitting element 3 is connected to one wiring layer. The other electrode of the light emitting element 3 is electrically connected to the other wiring layer 5b through the bonding wire 6, and then the epoxy is put in the recess 4 so as to cover the light emitting element 3. A display device as a final product is obtained by filling a transparent resin such as a resin and hermetically sealing the light emitting element 3.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is principal part sectional drawing which shows an example of embodiment about the light emitting element storage package of this invention. It is a top view of the light emitting element storage package of FIG. It is a top view which shows the other example of embodiment about the light emitting element storage package of this invention. It is a top view which shows the other example of embodiment about the light emitting element storage package of this invention. It is principal part sectional drawing which shows the other example of embodiment about the light emitting element storage package of this invention. It is a top view which shows the other example of embodiment about the light emitting element storage package of this invention. It is a top view which shows the other example of embodiment about the light emitting element storage package of this invention. It is a top view which shows the other example of embodiment about the light emitting element storage package of this invention. It is principal part sectional drawing which shows the other example of embodiment about the light emitting element storage package of this invention. It is principal part sectional drawing which shows the other example of embodiment about the light emitting element storage package of this invention. It is principal part sectional drawing of the conventional light emitting element storage package.

Explanation of symbols

1: Insulating substrate 3: Light emitting element 4: Recesses 5a, 5b: Wiring layer 7: Metal layer 8: Groove 9: Light blocking layer

Claims (4)

A light emitting element storage package in which a plurality of recesses for accommodating light emitting elements on an upper surface of an insulating substrate are arranged vertically and horizontally, and grooves are respectively formed in portions between the recesses on the upper surface and the lower surface of the insulating substrate. The grooves on the upper surface are arranged in parallel to each other, and the grooves on the lower surface are arranged in parallel to each other in a direction different from the grooves on the upper surface, and the grooves on the upper surface and the grooves on the lower surface are A light-emitting element storage package , wherein a light blocking layer that blocks light emitted from the light-emitting element is attached between the recesses adjacent to an inner surface . 2. The light emitting element storage package according to claim 1, wherein the groove on the upper surface and the groove on the lower surface are orthogonal to each other when seen in a plan view. 3. The light emitting device according to claim 1 , wherein the insulating base has a through-hole penetrating from the upper surface to the lower surface at a portion where the groove on the upper surface and the groove on the lower surface intersect each other. Storage package. A light emitting element storage package according to any one of claims 1 to 3, a light emitting element accommodated in each of the plurality of recesses, and a transparent resin covering the light emitting element. A light emitting device.

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