Light-emitting device and lighting device provided with the same

A light-emitting device capable of ensuring an electric connection between a light-emitting element and an electrode without generating any problem in practical use, by both connecting methods with a solder and a connector, and a lighting device provided with the light-emitting device are provided. The light-emitting device according to the present invention has a plurality of LED chips, and a soldering electrode land and a connector connecting electrode land electrically connected to the chips, on a ceramic substrate. The soldering electrode land is formed of a first conductive material having a function to prevent diffusion to a solder, and the connector connecting electrode land is formed of a second conductive material having a function to prevent oxidation.

CROSS REFERENCE TO RELATED APPLICATION

This Nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2010-222440 filed in Japan on Sep. 30, 2010 the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting device and a lighting device provided with the same.

2. Description of the Related Art

Conventionally, a light-emitting device is provided with a light-emitting element (refer to Japanese Patent Laying-Open No. 2007-116095 (hereinafter, referred to as the patent document 1)).

FIG. 12is a schematic structure diagram of a light-emitting device disclosed in the patent document 1. A light-emitting device100includes a LED chip101, and the LED chip101is mounted on a wiring substrate103. The wiring substrate103serves as a base member of the LED chip101.

An electrode provided on one surface side of the LED chip101is connected to a bonding wire105, and the bonding wire105extends in a direction along one diagonal line of the LED chip101.

References107and109each represent a conductor pattern, and each of them is composed of a laminated film having a Cu film, a Ni film, and an Au film. In a planar view, a part on the inner side of a frame (reflector (not shown)) serves as the inner lead107, and a part on the outer side of the frame serves as the outer lead109.

As disclosed in the patent document 1, in a case where the conductor pattern to be externally connected is formed of gold (Au film) on the substrate103, and a solder is used to externally connect the conductor pattern, the gold contained in the conductor pattern is diffused in the solder and an intermetallic compound is formed in some cases. Thus, when this phenomenon is repeatedly generated, the Au film, the Cu film, and the Ni film disappear, and an electrode land and the solder are not connected, which is inconvenient in practical use.

In addition, a user who wants to make an external connection with a connector other than the solder cannot use the light-emitting device disclosed in the patent document 1. Meanwhile, a user who wants to make the external connection with the solder suffers from the above problem.

SUMMARY OF THE INVENTION

The present invention was made in view of the above problem, and it is an object of the present invention to provide a light-emitting device capable of ensuring an electric connection between a light-emitting element and an electrode by both connecting methods with a solder and a connector without generating any problem in practical use, and a lighting device provided with the light-emitting device.

In addition, it is an object of the present invention to provide a light-emitting device capable of densely and compactly mounting LED chips.

In order to attain the above object, a light-emitting device according to the present invention is characterized by including a light-emitting part, and a soldering electrode land and a connector connecting electrode land each electrically connected to the light-emitting part, on a substrate, in which the soldering electrode land is formed of a first conductive material having a function to prevent diffusion to a solder, and the connector connecting electrode land is formed of a second conductive material having a function to prevent oxidation.

At this time, it is preferable that the soldering electrode land has an uppermost surface made of the first conductive material, and the connector connecting electrode land has an uppermost surface made of the second conductive material.

Here, the first conductive material includes any one of Ag, Ag—Pt and Ag—Pd.

In addition, the second conductive material includes Au.

Furthermore, the light-emitting device is further characterized in that the soldering electrode land includes a pair of a first soldering electrode land connected to an anode, and a second soldering electrode land connected to a cathode, and the connector connecting electrode land includes a pair of a first connector connecting electrode land connected to the anode and a second connector connecting electrode land connected to the cathode.

At this time, it is preferably that the substrate has a rectangular shape, and either or both of the pair of the first soldering electrode land and the second soldering electrode land, and the pair of the first connector connecting electrode land and the second connector connecting electrode land are arranged at corners of the substrate.

In addition, the light-emitting device is characterized in that a first wiring pattern connected to the anode, and a second wiring pattern connected to the cathode are arranged so as to be opposed to each other on the substrate, and the light-emitting part is electrically connected to the first soldering electrode land and the first connector connecting electrode land through the first wiring pattern, and electrically connected to the second soldering electrode land and the second connector connecting electrode land through the second wiring pattern.

At this time, the first wiring pattern and the second wiring pattern have respective arc shapes each constituting a part of the same circular ring, and the light-emitting part is covered with a sealing body filled in the circular ring.

In addition to the above characteristics, the light-emitting device is characterized by including a printing resistive element having one end connected to one end of the first wiring pattern, and having the other end connected to one end of the second wiring pattern, in which the printing resistive element has an arc shape constituting a part of the circular ring.

According to the shape of the above light-emitting device, the light-emitting device can show rotation symmetry with the LED chips arranged in the inner side of the circular ring. At this time, the series circuits each composed of the LED chips connected in series are arranged as parallel lines, so that the light-emitting device can implement high luminance of 25 W or more.

Thus, the LED chips arranged in the adjacent lines are incorporated in the series circuit, in the part close to an outer periphery of the circular ring in which the number of the chips arranged in one line is reduced, so that the series circuits each having the same number of LED chips can be arranged as many as possible in parallel, so that the LED chips can be densely arranged. Thus, the compact and high-luminance light-emitting device can be provided.

In addition, a lighting device is characterized by including the light-emitting device having the above characteristics, and a connector jig, in which the connector jig includes a resin plate having a light-emitting surface opening, and a connector terminal opening to be penetrated by a connector terminal, and the light-emitting device and the connector jig are overlapped in such a manner that the light-emitting part is exposed in the light-emitting surface opening, and the connector connecting electrode land and the connector terminal opening are opposed to each other.

In addition to the above characteristics, the lighting device is further characterized in that an outer periphery of the connector jig does not protrude from an outer periphery of the light-emitting device when viewed from a direction perpendicular to an overlapped surface of the light-emitting device and the connector jig.

According to the light-emitting device of the present invention, since the soldering electrode land and the connector connecting electrode land are both previously provided on the substrate, either one of the connection with the solder and the connector can be employed according to a usage way of the user when the user tries to ensure the external electric connection. Thus, a versatile light-emitting device can be provided.

In addition, in the case of the external connection with the solder, the present invention solves the problem that Au is diffused in the solder and the intermetallic compound is formed, so that electric connection cannot be ensured like the conventional case because the soldering electrode land is formed of the first conductive material having the function to prevent diffusion to the solder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A and 1Bare schematic structure diagrams showing one example of a light-emitting device of this embodiment. As shown inFIGS. 1A and 1B, a light-emitting device1according to this embodiment includes a ceramic substrate3, wiring patterns7(7aand7k), a phosphor containing resin layer9, LED chips11, a wire13, a printing resistive element15, soldering electrode lands17(17aand17k), connector connecting electrode lands19(19aand19k), a resin dam21, and positioning openings25. In addition,FIG. 1Ais a top view andFIG. 1Bis a cross-sectional view. InFIG. 1A, an inner side is transparently shown in order to make a connection relationship clear.

In addition,FIGS. 2A and 2Bare schematic views showing a state prior to the state shown inFIG. 1A.FIG. 2Ais a view showing a schematic structure before the LED chips11are mounted andFIG. 2Bis a view showing a schematic structure after the LED chips11are mounted and before the phosphor containing resin layer9and the resin dam21are formed.

The wiring pattern7a, and the electrode lands17aand19aare all electrically connected to an anode terminal, and the wiring pattern7k, and the electrode lands17kand19kare all electrically connected to a cathode terminal.

The ceramic substrate3is formed into a rectangular shape. For example, its outline is 24 mm×20 mm, and its thickness is 1 mm.

Thus, the electrode lands17aand19aconnected to the anode, and the electrode lands17kand19kconnected to the cathode are arranged at diagonally opposed corner parts of the ceramic substrate3, respectively.

The soldering electrode lands17aand17kare used when an external connection (for the purpose of power supply) with the wiring pattern7is made with a solder. Each of them is formed of Ag—Pt by a screen printing method. An example of its thickness is 20 μm.

The Ag—Pt layer is preferably formed on an uppermost layer of each of the soldering electrode lands17aand17k, but another metal layer may be thinly formed on the surface of the Ag—Pt layer because it is only necessary to prevent a diffusion reaction to the solder in the Ag—Pt layer. In addition, a metal layer having small specific resistance may be formed under the Ag—Pt layer.

The connector connecting electrode lands19aand19kare used when an external connection (for the purpose of power supply) with the wiring pattern7is made with a connector. Each of them is formed of Au by a screen printing method. An example of its thickness is 3 μm.

Here, the material Au used for the connector connecting electrode lands19aand19khas a feature that prevents an oxide film from being formed on a surface. Thus, the external electric connection can be easily ensured through a connector contact.

In addition, the Au layer is preferably formed on an uppermost surface of each of the connector connecting electrode lands19aand19kto be easily connected at the time of the connector contact, but a hard metal layer (such as Ti or W) having small specific resistance may be thinly formed to prevent a damage at the time of the connector contact. In addition, instead of the Au layer, a hard metal which is hardly oxidized and has small specific resistance may be used.

The wiring patterns7aand7kare formed on the ceramic substrate3so as to be opposed to each other. Each of them has an arc shape which is partially cut out from a circular ring when viewed from the top of the light-emitting device1. In addition, the soldering electrode land17ais connected to one end of the wiring pattern7athrough a leading line, and the soldering electrode land17kis connected to one end of the wiring pattern7kthrough a leading line. The connector connecting electrode land19ais electrically connected to the soldering electrode land17athrough a leading line or a contact electrode, and the connector connecting electrode land19kis also electrically connected to the soldering electrode land17kin a similar way.

The printing resistive element15is provided in order to enhance an electrostatic withstand voltage, and composed of RhO2having a resistance value of 50 MΩ, in which its width is 200 μm and its width is 6 μm. As shown inFIGS. 1A to 2B, the printing resistive element15is arranged so as to connect one end of the wiring pattern7aand one end of the wiring pattern7k, and has an arc shape partially cut out from a circular ring. According to this embodiment, each of the wiring pattern7a, the printing resistive element15, and the wiring pattern7kconstitutes a part of an outer periphery of the same circular ring.

The plurality of LED chips11are mounted on the ceramic substrate3. According to this embodiment, 12 series circuits each composed of 12 LED chips11are arranged as parallel lines.

In addition, the LED chips11are linearly arranged so as to be roughly parallel to one side of the substrate. Thus, the number of the chips in the line is greatest in the vicinity of the center of the circular ring shape composed of the wiring patterns7and the printing resistive element15, and the number of the chips is reduced toward the periphery of the substrate from the center, so that the LED chips can be densely arranged in an area surrounded by the wiring patterns7.

When the LED chips11are arranged as described above, the outline of the arranged LED chips11becomes the same (or similar) shape as the outline of the phosphor containing resin layer9(sealing body) when viewed from the top of the light-emitting device1. According to this embodiment, as shown inFigs. 1A and 1B, the shape of the sealing body has a circular shape when viewed from the top, and the outline of the arranged LED chips11also has a circular shape. This configuration can solve the problem that a light-emitting pattern cannot have the same shape as that of the sealing body due to a shadow caused because a light source is not arranged in the vicinity of the sealing body.

Basically, the adjacent LED chips11are directly connected by the wire13in the one LED chip line. However, in the vicinity of the periphery of the substrate in which the number of the chips in the same line is smaller, the LED chip is electrically connected to the LED chip in the adjacent line so that the number of the LED chips11is to be the same in each series circuit. The LED chip11arranged in the vicinity of the wiring pattern7is directly and electrically connected to the wiring pattern7through the wire.

The resin dam21is provided to dam the sealed resin and composed of a colored material (preferably white or milky white). According to this embodiment, the resin dam21is composed of a white silicon resin (containing TiO2as a filler) and formed into a circular ring shape having a width of 1 mm and a diameter of 9 mm. It is formed such that after the resin is applied, it is subjected to a curing treatment at 150° C. for 60 minutes. As shown inFIG. 1A, the resin dam21is preferably formed so as to cover the wiring patterns7, the printing resistive element15, and a part of the wire13.

The phosphor containing resin layer9is formed to convert the light (such as blue light) emitted from the LED chip to white light. According to this embodiment, a material containing a green phosphor (such as Ca3(Sr.Mg)2Si3O12:Ce) and a red phosphor (such as (Sr.Ca)AlSiN3:Eu) is injected into the inner side of the resin dam21formed into the ring shape, and thermally cured at 150° C. for 5 hours, whereby the phosphor containing resin layer9is formed.

According to this embodiment, as shown inFIG. 1A, the two positioning openings25are formed at the diagonally opposed corners of the ceramic substrate3. This opening25is used when a connector jig which will be described below is screwed on the light-emitting device1.

FIGS. 3A and 3Bare schematic structure diagrams showing the connector jig, and a state after the connector jig and the light-emitting device1are overlapped.FIG. 3Ashows the connector jig, andFIG. 3Bshows the state after the connector jig and the light-emitting device1are overlapped.

A connector jig31is provided to electrically connect the connector connecting electrode lands19(19aand19k) formed on the ceramic substrate3to an external line, and composed of a resin plate30having almost the same size as that of the ceramic substrate3. A positioning opening33, a connector terminal opening35, and a light-emitting surface opening39are formed in the resin plate30. A slanted part37is formed on an outer peripheral side surface of the light-emitting surface opening39and serves as a reflection member. The resin plate30is made of a resin such as PBT (polybutylene terephthalate) resin or a PC (polycarbonate) resin. According to this embodiment, the resin plate30is composed of a milky white or white PBT resin having a high reflection rate with respect to light emitted from the light-emitting part.

As shown inFIG. 3A, the positioning openings33are provided at one of two pairs of diagonally opposed corners of the connector jig31, and the connector terminal openings35are provided at the other of the two pairs of diagonally opposed corners thereof. The connector terminal opening35is configured so that the connector can be inserted from a side surface to the inner side of the resin plate30.

As shown inFIG. 3B, after the light-emitting device1and the connector jig31are overlapped, the opening25provided in the ceramic substrate3of the light-emitting device1is overlapped with the positioning opening33provided in the connector jig31. In addition, the light-emitting surface containing the LED chips11and the phosphor containing resin layer9is exposed in the light-emitting surface opening39. In addition, each of the connector connecting electrode lands19aand19kprovided in the light-emitting device1is partially opposed to the connector terminal opening35provided in the connector jig31in a vertical direction. InFIG. 3B, in order to clearly understand that the connector connecting electrode lands19aand19kexist under the connector terminal opening35, the resin plate30positioned just above them is transparently shown.

Thus, the connector jig31is set and a connector46is fit in the connector terminal opening35, whereby, as shown inFIG. 4, a lead (lead in the connector)41attached to the connector is electrically connected to the connector connecting electrode lands19aand19k. Thus, a screw43(such as M5screw) is fit in so as to penetrate the openings25and33and fixed to a case51. Then, a lens dome55is fit in, whereby a LED lighting device50is completed (refer toFIG. 5). In addition, inFIG. 5, reference53represents a cap and may be integrally provided with the case51.

FIG. 6is a conceptual view to explain a method to ensure the electric connection between the connector connecting electrode land19and the connector jig31when the resin plate30of the connector jig31and the ceramic substrate3of the light-emitting device1are to be overlapped. InFIG. 6, reference45represents a lead attached to the jig.

As described above, when the light-emitting device1and the connector jig31are overlapped such that the opening25provided in the ceramic substrate3and the positioning opening33provided in the resin plate30are overlapped, the connector terminal opening35provided in the connector jig31is opposed to the connector connecting electrode land19in the vertical direction. The lead45attached to the jig is provided in the connector jig31to electrically connect the lead41in the connector to the connector connecting electrode land19.

The lead45attached to the jig is formed of a conductive material wound into the form of a spring. The spring shape is provided to increase a contact area between the lead45and the connector connecting electrode land19to disperse force applied at the time of contact to prevent an edge of the lead45attached to the jig from sharply coming in contact with the surface of the connector connecting electrode land19and damaging the surface after the connector jig31and the light-emitting device1are overlapped. As described above, when fixed to the case51, the screw43is fit in the opening25and33so as to penetrate them, so that the lead45and the connector connecting electrode land19are surely connected electrically.

In addition, as shown inFIG. 6B, it is preferable that a click48is previously formed in the connector terminal opening35to prevent the connector46inserted in the connector terminal opening35from escaping.

In addition, when the light-emitting device1of this embodiment is externally connected with soldering, as shown inFIG. 7, the soldering electrode land17(17aand17k) is soldered, whereby an external lead42can be electrically connected to the soldering electrode land17through a solder47. Thus, the ceramic substrate3is fixed to the case51by a press part49. According to the light-emitting device1of this embodiment, although both of the soldering electrode land17and the connector connecting electrode land19are provided, since each of them is arranged in the vicinity of the corner of the ceramic substrate3, a space for providing the press part49can be sufficiently provided in the periphery of the substrate3.

Thus, the whole is fixed by a screw44with the ceramic substrate3and the case51fixed to each other by the press part49. After that, similar to the case of the connector connection, the lens dome55is fit in, whereby the LED lighting device50is formed (refer toFIG. 5).

According to the configuration of this embodiment, since each of the soldering electrode land17(17aand17k) and the connector connecting electrode land19(19aand19k) is previously provided on the ceramic substrate3, either one of the methods of soldering and connector connecting can be employed according to a usage mode of a user when the wiring pattern7is electrically connected to the outside. In addition, in the case where the external connection is provided with soldering, the conventional problem that Au is diffused in the solder and forms an intermetallic compound so that the electric connection cannot to be ensured is not caused because the soldering electrode land17is not formed of Au.

In addition, the LED chips can be densely arranged in the light-emitting device having the circular shape viewed from the top, which contributes to miniaturization of the lighting device having high luminance of 25 W.

Furthermore, in the case where the light-emitting device1according to this embodiment is externally connected through the connector, the connector jig having almost the same size as that of the ceramic substrate3having the LED chips11is overlapped. At this time, since the connector jig31has the openings (33,35, and39) corresponding to the structure of the ceramic substrate3, positioning is automatically made when it is overlapped. Thus, the light-emitting part (LED chips11) of the light-emitting device1can be positioned. In addition, since the connector jig31is composed of the resin plate30, the ceramic substrate3having the LED chips11can be protected.

The arrangement positions of the soldering electrode land17and the connector connecting electrode land19are not limited to those shown inFIG. 1A. Hereinafter, a variation will be described with reference toFIGS. 8A to 9B.

According to a variation shown inFIG. 8A, the light-emitting device1is provided such that the wiring pattern7ais electrically connected to the connector connecting electrode land19athrough a leading line connected to a region around the center of the wiring pattern7a, and the wiring pattern7ais electrically connected to the soldering electrode land17athrough a leading line extending from the connector connecting electrode land19a. This is applied to the connector connecting electrode land19kand the soldering electrode land17k.

When the wiring pattern7is externally connected through the connector terminal, in the light-emitting device1shown inFIG. 8A, the connector jig31shown inFIG. 8Bis overlapped with the ceramic substrate3. The connector jig31shown inFIG. 8Bis provided such that the connector terminal openings35are arranged almost in the center of opposed one pair of sides, in a peripheral part of the resin plate30, and the connector jig31is overlapped with the ceramic substrate3, whereby each of the connector connecting electrode lands19(19aand19k) is partially exposed in each of the connector terminal openings35. The positioning opening33and the light-emitting surface opening39are formed similarly to the above embodiment.

Thus, the external connection can be made through the connector by the same method as shown inFIG. 4, and the external connection can be made through the solder by the same method as shown inFIG. 7.

In addition, according to a variation shown inFIG. 9A, the light-emitting device1is provided such that the connector connecting electrode lands19aand19kare arranged at one diagonally opposed pair of corners of the ceramic substrate3, and the soldering electrode lands17aand17kare arranged at the other diagonally opposed pair of corners of the ceramic substrate3. That is, the connector connecting electrode lands19aand19k, and the soldering electrode lands17aand17kare formed at the four corners of the ceramic substrate3, respectively. In addition, the opening25is provided almost in the center of the opposed one pair of sides, in a peripheral part of the ceramic substrate3.

Thus, the connector connecting electrode land19ais electrically connected to one terminal of the wiring pattern7athrough a leading line, and the soldering electrode land17ais electrically connected to the other terminal of the wiring pattern7athrough a leading line. Similarly, the connector connecting electrode land19kis electrically connected to one terminal of the wiring pattern7kthrough a leading line, and the soldering electrode land17kis electrically connected to the other terminal of the wiring pattern7kthrough an leading line.

When the wiring pattern7is externally connected through a connector terminal, in the light-emitting device1shown inFIG. 9A, the connector jig31shown inFIG. 9Bis overlapped with the ceramic substrate3. The connector jig31shown inFIG. 9Bis provided such that the connector positioning openings33are arranged almost in the center of opposed one pair of sides, in a peripheral part of the resin plate30, and the connector jig31is overlapped with the ceramic substrate3, whereby the positioning openings33are overlapped with the openings25, respectively. In addition, the connector terminal openings35are provided at one diagonally opposed pair of corners, and when the connector jig31is overlapped with the ceramic substrate3, the connector connecting electrode land19is partially exposed in the connector terminal opening35.

Thus, the external connection can be made through the connector by the same method as shown inFIG. 4, and the external connection can be made through the solder by the same method as shown inFIG. 7.

FIGS. 10A and 10Bare additional schematic structure diagrams showing the state in which the connector jig31and the light-emitting device1are overlapped, in the configuration shown inFIGS. 9A and 9B.FIG. 10Ais a view showing a state when viewed from the top without a part of the light-emitting device being transparently shown, andFIG. 10Bis a view showing a cross-sectional state cut by a line connecting the two opposed openings25(33). As described above, the LED chips11are formed under the resin layer9, and the lead45attached to the jig and the connector connecting electrode land19are formed under the connector connecting opening35although not shown in the drawing.

FIGS. 11A and 11Bare additional schematic structure diagrams showing the state in which the connector jig31and the light-emitting device1are overlapped, in the configurations shown inFIGS. 1A and 1B, andFIGS. 8A and 8B, respectively when viewed from the top without a part of the light-emitting device being transparently shown, similar toFIG. 10A.FIGS. 10A and 10B, andFIGS. 11A and 11Bare provided to understand the structure.

Hereinafter, other embodiments will be described.(1) While the ceramic substrate is used as the substrate3in the above embodiment, the substrate may be a metal core substrate provided such that an insulation layer is formed on a surface of a metal substrate serving as a core.(2) While the soldering electrode land17is made of Ag—Pt in the above embodiment, it only has to contain a conductive material (corresponding to a first conductive material) having a function to prevent diffusion to the solder. Thus, the material may include Ag or Ag—Pd other than the Ag—Pt. In addition, at this time, it is preferable that an uppermost surface part which is in contact with at least the solder is made of the first conductive material.

In addition, while the connector connecting electrode land19is made of Au in the above embodiment, it only has to contain a conductive material (corresponding to a second conductive material) having a function to prevent oxidation from proceeding. The material Au is used as one example of the conductive material to prevent the oxidation from proceeding. In addition, at this time, it is preferable that an uppermost surface which is in contact with the lead (the lead45attached to the jig in the structure shown inFIG. 6) electrically connected to at least the connector is made of the second conductive material.(3) While the adjacent LED chips11are directly and electrically connected by the wire13in the above embodiment, they may be connected through a relay electrode.(4) While the soldering electrode land17is provided on the same side (main surface side) as the connector connecting electrode land19, on the ceramic substrate3in the above embodiment, it may be provided on a back surface side of the substrate3. In this case, a penetration electrode which penetrates the substrate to be connected to the wiring pattern7is provided, so that the soldering electrode land17provided on the back surface side is electrically connected to the penetration electrode.

In addition, the soldering electrode land17may be provided on a side surface of the substrate3.(5) The shapes of the electrode lands (17and19) and the openings (25,33, and35) are only shown as one example, and other shapes may be employed.(6) While the resin plate30constituting the connector jig31has almost the same size as that of the ceramic substrate3having the LED chips11in the above embodiment, the resin plate30may have any size. However, with a view to miniaturizing the lighting device50, the resin plate30is preferably miniaturized within a range in which the openings (25and33) of the resin plate30and the ceramic substrate3can be overlapped. That is, it is preferable that the outer periphery of the connector jig31does not protrude from the outer periphery of the light-emitting device1when viewed from a direction perpendicular to the overlapped surface of the light-emitting device and the connector jig.(7) While one or both of the soldering electrode land17and the connector connecting electrode land19are arranged at the corners of the ceramic substrate3in the above embodiment, the arrangement position is not limited to the corner. However, the case where the electrode land is arranged at the corner of the ceramic substrate3is preferable because a space for the opening25can be sufficiently ensured in the ceramic substrate3, and a ratio of the light emitted from the LED chip11absorbed by the electrode lands (17and19) can be reduced.(8) While the connector jig31is composed of the white or milky white resin plate30in the above embodiment, the connector jig31may be composed of a transparent member in a case where it is used only for fixing the ceramic substrate3to ensure the connector connection without having a function as a reflection member.(9) While the light-emitting device1has the printing resistive element15in the above embodiment, the printing resistive element is not necessarily provided when the withstand voltage protecting function is not executed. In addition, as an element having the withstand voltage protecting function, a zener diode may be mounted instead of the printing resistive element.(10) While the 12 series circuits each composed of 12 LED chips11connected in series are arranged as parallel lines on the substrate3in the above embodiment, as a matter of course, the number of the LED chips11connected in series, and the number of the series circuits (parallel line number) are not limited to the above numbers. In addition, the number of chips connected in series is not necessarily equal to the number of the parallel series circuits.

In addition, inFIG. 1A, the LED chips11of the adjacent lines are appropriately connected in series in the vicinity of the peripheral part of the substrate in which the number of the chips belonging to the same line is smaller, so that the number of the LED chips11constituting the series circuit can be equalized. At this time, the LED chips11in the three or more adjacent lines may be incorporated as the components of the series circuit.(11) While the connector46is inserted from the side surface of the resin plate30into the connector terminal opening35in the above embodiment, the inserting direction of the connector46is not limited to the above direction. In addition, the shape of the lead45attached to the jig to make the electrical connection between the lead41in the connector and the connector connecting electrode land19is not limited to the spring shape like this embodiment.

Although the present invention has been described in terms of the preferred embodiment, it will be appreciated that various modifications and alternations might be made by those skilled in the art without departing from the spirit and scope of the invention. The invention should therefore be measured in terms of the claims which follow.