WO2006035626A1 - Light-emitting unit - Google Patents

Abstract

Disclosed is a light-emitting unit comprising a multilayer chip varistor and a light-emitting device integrally mounted on the surface of the multilayer chip varistor.

Description

 Specification

 Light emitter unit

 Technical field

 The present invention relates to a light emitter unit in which a light emitting element and a surge countermeasure element are integrated.

 Background art

 [0002] Some electronic devices are provided with a light emitting element using a light emitting diode (LED). These light emitting elements are connected in parallel with surge countermeasure elements to prevent them from being destroyed by unexpected application of overvoltage such as static electricity. Such light-emitting elements and surge countermeasure elements are each composed of a chip component on which an LED that forms a light-emitting element on a support substrate and a Zener diode that forms a surge countermeasure element are mounted. In conventional light emitter units using these, LEDs and Zener diodes are individually mounted on a base substrate that forms an electronic device. Such a light emitter unit is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-124506.

 [0003] However, LEDs and Zener diodes each have directionality in external connection. That is, there are an anode side terminal and a force sword side terminal. For this reason, when mounting these components on the base board, the directionality must be checked each time, and productivity is low.

 Disclosure of the invention

 [0004] The light emitting unit of the present invention includes a multilayer chip varistor and a light emitting element integrally mounted on the surface of the multilayer chip varistor. By adopting such a configuration, the work for confirming the connection direction is reduced when the luminous unit is incorporated into the device, and the productivity of incorporation into the device is increased.

 Brief Description of Drawings

 [0005] FIG. 1 is a perspective view of a light emitter unit according to Embodiment 1 of the present invention.

 FIG. 2 is a cross-sectional view of the light emitter unit shown in FIG.

 FIG. 3A is a diagram showing steps in a method of manufacturing the light emitter unit shown in FIG.

FIG. 3B is a cross-sectional view showing a step that follows the step shown in FIG. 3A. FIG. 3C is a cross-sectional view showing a step that follows the step shown in FIG. 3B.

FIG. 3D is a cross-sectional view showing a step that follows the step shown in FIG. 3C.

FIG. 3E is a cross-sectional view showing a step that follows the step shown in FIG. 3D.

FIG. 4 is a perspective view of a light emitter unit according to Embodiment 2 of the present invention.

FIG. 5 is a cross-sectional view of the light emitter unit shown in FIG.

 6A is a perspective view showing steps of a method for manufacturing the light emitter unit shown in FIG. 4. FIG.

FIG. 6B is a cross-sectional view showing a step that follows the step shown in FIG. 6A.

FIG. 6C is a cross-sectional view showing a step that follows the step shown in FIG. 6B.

FIG. 6D is a cross-sectional view showing a step that follows the step shown in FIG. 6C.

FIG. 6E is a cross-sectional view showing a step that follows the step shown in FIG. 6D.

FIG. 7 is a perspective view of a light emitter unit according to Embodiment 3 of the present invention.

FIG. 8 is a cross-sectional view of the light emitter unit shown in FIG.

 FIG. 9 is a cross-sectional view including a through-hole provided in the surface of the light emitter unit shown in FIG.

 FIG. 10 is a perspective view of a light emitter unit according to Embodiment 4 of the present invention.

FIG. 11 is a cross-sectional view of the light emitter unit shown in FIG.

 [FIG. 12A] FIG. 12A is a perspective view showing steps of a method of manufacturing the light emitter unit shown in FIG.

 FIG. 12B is a cross-sectional view showing a step that follows the step shown in FIG. 12A.

FIG. 12C is a cross-sectional view showing a step that follows the step shown in FIG. 12B.

FIG. 12D is a cross-sectional view showing a step that follows the step shown in FIG. 12C.

FIG. 12E is a cross-sectional view showing a step that follows the step shown in FIG. 12D.

Explanation of symbols

1 Multilayer chip varistor

2 Light emitting element

4 Resin

5 Laminate 6 Internal electrode

 7 End electrode

 9 Wire bonding

 10 Connection electrode

 11 Green sheet

 12 Sintered body

 13 White substrate

 14 Through hole

 15 External display symbol

 BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, components having the same configuration as that of the preceding embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

 [0008] (Embodiment 1)

 1 and 2 are a perspective view and a cross-sectional view, respectively, of the light emitter unit according to Embodiment 1 of the present invention. The light emitter unit in the present embodiment is used for a backlight for liquid crystal screens and various switch display lights. The luminous body unit has a multilayer chip varistor 1 which is a surge countermeasure element and a light emitting element 2 which is an LED element. That is, the light emitting element 2 has connection directionality. The light emitting element 2 is integrally mounted on the multilayer chip varistor 1. The multilayer chip varistor 1 is provided in order to reduce the influence of a surge on the light emitting element 2. The molded resin 4 is provided on the surface of the multilayer chip varistor 1 so as to cover the light emitting element 2. Resin 4 is light transmissive, and for example, a transparent resin such as epoxy resin, silicon resin, heat-resistant acrylic resin, polycarbonate resin, and polyolefin can be used.

In this light emitting unit, as shown in FIG. 2, a multilayer chip varistor 1 is used as a surge countermeasure element. In the multilayer chip varistor 1, internal electrodes 6 are arranged opposite to each other in the stacking direction on the inner layer portion of the stacked body 5. Laminate 5 is a zinc oxide nostalgic material made by a ceramic technique using zinc oxide as a main raw material and several additives. It consists of fees. The internal electrode 6 is mainly composed of silver (Ag), platinum (Pt), palladium (Pd), or an alloy thereof. The laminated body 5 becomes a ceramic that functions as the laminated chip varistor 1 by sintering.

 [0010] End face electrodes 7 are provided on opposite end faces of the laminated body 5 after sintering. The end face electrode 7 is connected to the internal electrode 6 and the connection electrode 10. When a potential difference higher than the rated voltage is generated between the end face electrodes 7, the resistance between the end face electrodes 7 is extremely reduced, and the end face electrodes 7 appear to be short-circuited. A connection electrode 10 for connecting the light emitting element 2 by the wire bonding 9 is provided on the upper surface of the laminated body 5 after sintering.

 [0011] According to this configuration, the light emitting element 2 and the multilayer chip varistor 1 are integrated in advance.

 Therefore, it is only necessary to confirm directionality when mounting the light emitter unit on the base substrate (not shown) constituting the electronic device. As a result, the productivity of electronic equipment using this light emitting unit is improved, and the area occupied by the light emitting unit on the base substrate is reduced, contributing to the miniaturization of electronic equipment.

 [0012] In addition, by using the multilayer chip varistor 1 as a surge countermeasure element, a support substrate for mounting the corner diode, which is necessary when using a conventional corner diode that is a surge countermeasure element, becomes unnecessary. Therefore, the light emitting unit is further reduced in size and weight.

Next, a method for manufacturing the light emitter unit will be described with reference to FIGS. 3A to 3E. First, as shown in FIG. 3A, green sheets 11 mainly made of a zinc oxide varistor material on which internal electrodes 6 and connection electrodes 10 are printed are stacked appropriately. Then, the laminate 5 having the internal electrode 6 and the connection electrode 10 is formed. Next, as shown in FIG. 3B, the laminate 5 is fired to simultaneously sinter the internal electrode 6, the connection electrode 10, and the green sheet 11 to obtain a sintered body 12. Next, as shown in FIG. 3C, an end face electrode 7 for external connection is formed on and around the end face of the sintered body 12. The end surface electrode 7 is formed, for example, by applying and baking a conductive paste containing Ag or the like. Further, a plating layer may be formed thereon. Further, as shown in FIG. 3D, the light-emitting element 2 is bonded to the upper surface of the sintered body 12 with an adhesive, and the terminals of the light-emitting element 2 are electrically connected to the connection electrode 10 by wire bonding 9. Finally, as shown in FIG. 3E, the light emitting unit is manufactured by molding with resin 4 so as to cover light emitting element 2. [0014] (Embodiment 2)

 4 and 5 are a perspective view and a cross-sectional view, respectively, of the light emitter unit according to Embodiment 2 of the present invention. In the light emitter unit according to the present embodiment, the light emitting element 2 is mounted on the upper surface of the multilayer chip noristor 1 that is a surge countermeasure element via a white substrate 13. That is, the multilayer chip varistor 1 has a white substrate 13 on the surface on which the light emitting element 2 is mounted. Other configurations are the same as those in the first embodiment.

 [0015] When the multilayer chip varistor 1 is used as a surge countermeasure element, a zinc oxide varistor material is used as a main raw material, so that the color is a dark green color such as dark green. As a result, it is difficult for the light to be reflected. As a result, the light emitted from the light emitting element 2 to the multilayer chip parser 1 side is not effectively used. As a result, the utilization efficiency of the light emitted from the light emitting element 2 is lowered. Therefore, in order to increase the light utilization efficiency, it is preferable to interpose a white substrate 13 having a high light reflectance between the light emitting element 2 and the multilayer chip varistor 1.

 That is, when a white substrate 13 such as an alumina substrate is interposed between the light emitting element 2 and the multilayer chip lister 1, the light power emitted from the light emitting element 2 toward the white substrate 13 is white. Reflected on the surface of the substrate 13. Since the reflected light is effectively used in this way, the light use efficiency increases as a light emitting unit. Here, the color of the white substrate 13 is not necessarily white. It may be slightly yellowish or bluish.

 In addition, it is preferable to use an alumina substrate as the white substrate 13. In this case, the hardness of the alumina substrate is higher than that of the laminated body 5 after sintering made of the zinc oxide varistor material forming the laminated chip varistor 1. Therefore, as a result, the strength of the light emitter unit in which these are integrated is increased, and this is particularly effective when downsizing.

[0018] Next, a method for manufacturing the light emitter unit will be described with reference to FIGS. 6A to 6E. First, as shown in FIG. 6A, a green sheet 11 made mainly of a zinc oxide varistor material on which internal electrodes 6 are printed is appropriately stacked on a white substrate 13 on which connection electrodes 10 are formed. Next, as shown in FIG. 6B, a laminated body 5 having internal electrodes 6 and connection electrodes 10 is formed, and the laminated body 5 is fired. At this time, the internal electrode 6, the connection electrode 10, and the green sheet 11 are simultaneously sintered to obtain a sintered body 12. Next, as shown in FIG. The end face electrode 7 for connecting the part is formed. Further, as shown in FIG. 6D, the light emitting element 2 is bonded to the surface of the white substrate 13 in the sintered body 12 with an adhesive, and the terminal of the light emitting element 2 is electrically connected to the connection electrode 10 by wire bonding 9. . Finally, as shown in FIG. 6E, a light emitter unit is manufactured by molding with a resin 4 so as to cover the light emitting element 2.

 Note that a glass ceramic that can be sintered at a low temperature may be used as the white substrate 13. In this case, in the step shown in FIG. 6A, a green sheet mainly made of zinc oxide varistor material is appropriately stacked on the green sheet made of glass ceramic, and in the step shown in FIG. 6B, the internal electrode 6 and the connecting electrode 10 And forming an unsintered laminate 5 integrated with the glass ceramic sheet. Other steps are the same as above.

[0020] In this manufacturing method, a glass ceramic sheet and a green sheet made mainly of a zinc oxide varistor material are sintered simultaneously. Therefore, the occurrence of internal structural defects due to sintering shrinkage can be prevented more reliably. Further, the bond between the white substrate 13 and the multilayer chip varistor 1 becomes stronger and the mechanical strength is improved.

 [Embodiment 3]

 FIG. 7 is a perspective view of a light emitter unit according to Embodiment 3 of the present invention. 8 and 9 are cross-sectional views of the light emitter unit according to the present embodiment, FIG. 8 shows a cross-section at the location of the mold resin, and FIG. 9 shows a cross-section at the location where the through hole is provided. In the light emitting unit in the present embodiment, the through hole 14 is provided on the surface of the white substrate 13, particularly in a region not covered with the mold resin 4. Other configurations are the same as those in the second embodiment.

 By providing the through hole 14 in this way, the surface of the multilayer chip varistor 1 is exposed through the through hole 14. Therefore, the through hole 14 can be used to indicate the connection direction of the light emitting unit.

 [0023] This luminous body unit is a multilayer chip varistor which is a directional and surge countermeasure element having no directionality.

1 is a configuration in which a light-emitting element 2 is mounted with a directional LED element. For this reason, the pair of end face electrodes 7 that are used for external connection of the luminous body unit have a connection direction and light emission. It is necessary to show this direction as a body unit. In the present embodiment, by providing the through hole 14 in the white substrate 13, the dark green surface exposed from the through hole 14 functions as a direction recognition mark and can show directionality.

 [Embodiment 4]

 10 and 11 are a perspective view and a cross-sectional view, respectively, of the light emitter unit according to Embodiment 4 of the present invention. In the light emitting unit in the present embodiment, an electrode containing a metal such as silver as a main component is provided as the external display symbol 15 on the lower surface side of the multilayer chip varistor 1 which is a surge countermeasure element. That is, the external display symbol 15 is provided on the surface opposite to the surface on which the light emitting element 2 is mounted.

 [0025] As described in Embodiment 3, since an LED element is used as the light-emitting element 2, directionality occurs as a light-emitting unit. In the present embodiment, an external display symbol 15 is provided to indicate this direction.

 The zinc oxide varistor material forming the multilayer chip varistor 1 which is a surge countermeasure element is a deep green and dark color system. On the other hand, the external display symbol 15 is composed of a silver-based silver electrode having a clear contrast with respect to the dark color system. As a result, the direction recognition accuracy of the mounting machine that mounts the light emitter unit on the base substrate is increased, and the productivity is further increased.

 [0027] Next, a method for manufacturing the light emitter unit will be described with reference to FIGS. 12A to 12E. First, as shown in FIG. 12A, green sheets 11 mainly made of zinc oxide noristor material on which internal electrodes 6, connection electrodes 10, and external display symbols 15 are printed are stacked appropriately. Next, as shown in FIG. 12B, the laminate 5 having the internal electrode 6, the connection electrode 10, and the external display symbol 15 is formed and fired. At this time, the internal electrode 6, the connection electrode 10, the external display symbol 13, and the green sheet 11 are simultaneously sintered to obtain a sintered body 12. Hereinafter, the steps shown in FIGS. 12C to 12E are the same as the steps shown in FIGS. 3C to 3E in the first embodiment.

It should be noted that the external display symbol 15 may be provided on the surface opposite to the white substrate 13 with respect to the configuration having the white substrate 13 as in the second embodiment. The external display symbol 15 is formed of an electrode containing a silver-colored metal such as silver, but may be composed of other metals as long as it can be distinguished from a dark-colored zinc oxide varistor material. However, it is preferable to include at least a metal such as silver which is relatively whitish and easy to distinguish. This electrode is also made of metal It may be formed by baking a paste containing glass or the like containing a metal powder as a main component. Alternatively, a conductive resin containing metal powder and resin may be used.

[0029] In any of the light emitter units according to the above-described embodiments of the present invention, the light emitting element 2 is mounted on the surface of the multilayer chip paris. The end face electrode 7 covers the vicinity of the end face of the multilayer chip node 1 and the face adjacent to the end face. For this reason, the direction of light emission can be easily changed by changing the mounting direction (posture) on the circuit board. That is, usually, the light emitting unit is mounted on the substrate so that the light emitting element 2 faces upward, and emits light toward the side facing the upper surface of the substrate. In addition to this, for example, when the light emitter unit is mounted so that the light emitting element 2 is inclined by 90 ° with respect to the substrate, the light emitter unit emits light in a direction parallel to the substrate. A so-called side view light emission mode is possible.

 In the above embodiment, the light emitting element 2 is described as an LED element. However, the light emitting element is not particularly limited as long as it has a connection directionality.

 In the present embodiment, a multilayer chip varistor made of a zinc oxide varistor material has been described as an example. However, the present invention is not limited to this. For example, a multilayer chip varistor made of a strontium titanate material is used. But you can. Industrial applicability

[0032] The light emitting unit according to the present invention is useful when it is used in electronic equipment such as a backlight of a liquid crystal screen, in which the productivity of incorporation into the equipment is high.

Claims

The scope of the claims  [1] Multilayer chip varistor,  And a light emitting element integrally mounted on the surface of the multilayer chip varistor.  [2] The multilayer chip varistor has a white substrate on a surface on which the light emitting element is mounted, and the light emitting element is mounted on the multilayer chip noristor via the white substrate. Luminous body unit. [3] The white substrate is an alumina substrate.  The light emitter unit according to claim 2. [4] The multilayer chip varistor is made of a ceramic mainly composed of zinc oxide, and the white substrate is made of a glass ceramic.  The light emitter unit according to claim 2. [5] The white substrate is provided with a through hole, and a surface of the multilayer chip varistor is exposed from the through hole.  The light emitter unit according to claim 2. [6] The multilayer chip varistor is made of a ceramic mainly composed of zinc oxide.  The light emitter unit according to claim 5. [7] An external display symbol is provided on the surface of the multilayer chip varistor opposite to the surface on which the light emitting element is mounted.  The light emitter unit according to claim 1. [8] The external indication symbol is an electrode containing a metal, and the multilayer chip varistor is made of a ceramic mainly composed of zinc oxide.  The light emitter unit according to claim 7. [9] The electrode includes at least silver.  The light emitter unit according to claim 8.