Patent Publication Number: US-2012037939-A1

Title: Light emitting diode

Description:
TECHNICAL FIELD 
     The invention relates generally to light emitting diodes and, more particularly, to a light emitting diode comprising a light emitting diode chip having high brightness and a package in which the light emitting diode chip is housed. 
     BACKGROUND ART 
     In the past, there have been proposed various light emitting diodes, comprising light emitting diode chips (LED chips) having high brightness, packages in which the LED chips are housed, and connection electrodes electrically connected to element electrodes with which the LED chips are provided. Then, most of the packages are cannon-ball type packages or surface-mount type packages. An example of the cannon-ball type packages is described in Japanese Patent Application Laid-Open No. 2006-140407 published on Jun. 1, 2006. Then, an example of the surface-mount type packages is described in Japanese Patent Application Laid-Open No. 2007-12727 published on Jan. 18, 2007. 
     A connection electrode in a cannon-ball type package is formed into a linear shape, and projects from one surface of the package into the outside. Then, a connection electrode in a surface-mount type package is formed into a sheet, and projects from a periphery of the package into the outside. In addition, in both configurations, the LED chip housed in the package is sealed with a synthetic resin molding product or by potting a synthetic resin, and thereby is protected. 
     By the way, in the cannon-ball type package, the connection electrode is located so as to project from one surface of the package, facing toward a direction opposite to a light irradiation direction. Thereby, high-density of LED placement can be achieved when a plurality of packages are arranged. However, it is difficult to secure a heat dissipation member to this kind of light emitting diode. Thus, there is a problem not to be able to ensure heat dissipation performance. 
     On the other hand, in the surface-mount type package, it is easy to secure the heat dissipation member to one surface of the package, facing toward a direction opposite to a light irradiation direction, and thus the heat dissipation performance can be ensured. However, the connection electrode is located so as to project from a periphery of the package. Thus, there is a problem not to be able to achieve high-density of LED placement when a plurality of packages are arranged. 
     That is, the conventional light emitting diodes have a problem that it is difficult to improve both heat dissipation performance and density of LED placement together. 
     DISCLOSURE OF THE INVENTION 
     It is an object of the present invention to provide a light emitting diode, which can improve both heat dissipation performance and density of LED placement together. 
     A light emitting diode of the present invention comprises a LED chip, a package in which the LED chip is housed, and a connection electrode electrically connected to an element electrode with which the LED chip is provided. The package is a laminated body comprising at least a submount substrate and a frame body. The LED chip is fixedly-mounted on one surface of the submount substrate. The frame body is laminated on the one surface of the submount substrate, and is provided with a through-hole in which the LED chip is stored. According to a first aspect of the present invention, the connection electrode is formed on at least either the one surface of the submount substrate or one surface of the frame body facing toward a light irradiation direction, while being exposed in the light irradiation direction. In this configuration, because the connection electrode is formed on at least either the one surface of submount substrate or one surface of the frame body facing toward a light irradiation direction, while being exposed in the light irradiation direction, the light emitting diode can be formed so that the connection electrode does not project from a periphery of the package or a rear surface of the package facing toward a direction opposite to the light irradiation direction. Therefore, one can easily secure the heat dissipation member to the rear surface of the package facing toward a direction opposite to a light irradiation direction. In particular, the LED chip is fixedly-mounted on the one surface of the submount substrate, and thus the light emitting diode can radiate heat more effectively by securing the heat dissipation member to the rear surface of the package, as described above. Then, when a plurality of packages are arranged and constitute one light source, adjacent packages can be closely located each other. That is, density of LED placement can be improved. Therefore, the light emitting diode can improve both heat dissipation performance and density of LED placement together. 
     In an embodiment, an inner periphery face of the through-hole is formed so that a diameter thereof gradually increases toward the light irradiation direction from the submount substrate. The through-hole is provided with a conductive connecting pattern electrically connected to the connection electrode on the inner periphery face. The connecting pattern is electrically connected to the element electrode of the LED chip. In this configuration, an inner periphery face of the through-hole is formed so that a diameter thereof gradually increases toward the light irradiation direction from the submount substrate. Therefore, one can easily perform connection work to electrically connect the element electrode with the connection electrode, even if a storage space for the LED chip, surrounded by the inner periphery face of the through-hole, is relatively small. 
     In an embodiment, the connection electrode comprises a first connection electrode and a second connection electrode. The first connection electrode is formed on the one surface of the submount substrate, and the second connection electrode is formed on the one surface of the frame body facing toward the light irradiation direction. The first and second connection electrodes are electrically insulated from each other. In this configuration, because the first connection electrode is formed on the one surface of the submount substrate, and the second connection electrode is formed on the one surface of the frame body facing toward the light irradiation direction, the first and second connection electrodes can be located so as to have a difference in height each other. Therefore, it becomes easy to distinguish the polarity of these electrodes. 
     In an embodiment, the package is formed into a rectangular shape as viewed from the light irradiation direction. The frame body is provided with a first electrode window, and then the first electrode window exposes the first connection electrode located in each of two corner portions on the one surface of the submount substrate. The frame body is provided with the second connection electrode in each of the remaining two corner portions. In this configuration, because the package is formed into a rectangular shape as viewed from the light irradiation direction and the first connection electrode is exposed by the first electrode window formed in each of the two corner portions of the frame body and the frame body is provided with the second connection electrode in each of the remaining two corner portions, a whole of the package can be formed into a rectangular solid. Thus, when a plurality of packages are arranged, the density of LED placement can be improved more. Then, if the connection electrodes having one polarity are located in adjacent two corner portions of four corner portions in the package and the connection electrodes having the other polarity are located in the remaining adjacent two corner portions and a direction of the package is adjusted, one can easily perform connection work to electrically connect a plurality of packages together. 
     According to a second aspect of the present invention, the frame body is formed by lamination of a plurality of frame boards. Then, one frame board of the plurality of frame boards comprises a connection piece projecting into the through-hole, and the one frame board is something other than a frame board laminated at the outmost edge in the light irradiation direction. The connecting pattern is located on one surface of the connection piece facing toward the light irradiation direction. In this configuration, because the connecting pattern is located on one surface of the connection piece facing toward the light irradiation direction, the connecting pattern&#39;s size can be ensured easily even if the package&#39;s size is reduced. Therefore, one can easily perform connection work to connect the LED chip with the connecting pattern. 
     According to a third aspect of the present invention, the package comprises a window cover. The window cover is laminated on the submount substrate via the frame body, and is transparent to light radiated from the LED chip. In this configuration, because the package comprises the window cover, the package can protect the LED chip from environment, and thus the LED chip can have a long life. 
     In an embodiment, the submount substrate, the frame body, and the window cover are secured together so that an inside of the through-hole is airproofed. In this configuration, the submount substrate, the frame body, and the window cover are secured together so that an inside of the through-hole is airproofed, the package can protect the LED chip from environment, and attenuation of light intensity can be inhibited compared with potting of a synthetic resin, and luminous efficiency can be increased. In addition, although it depends on a selected material, the window cover has a wide choice of material compared with the synthetic resin used for potting. Thus, if a material with highly-heat and light resistance is selected for the window cover, the light emitting diode can have a longer life. 
     In an embodiment, the connection electrode comprises a first connection electrode and a second connection electrode, and the first connection electrode is formed on the one surface of the submount substrate, the second connection electrode is formed on the one surface of the frame body facing toward the light irradiation direction. The first and second connection electrodes are electrically insulated from each other. The package is formed into a rectangular shape as viewed from the light irradiation direction. The frame body is provided with a first electrode window, and the first electrode window exposes the first connection electrode located in each of two corner portions on the one surface of the submount substrate. The window cover is provided with a second electrode window, and the second electrode window exposes the first electrode window and the second connection electrode located in each of the remaining two corner portions of the frame body. In this configuration, because the package is formed into a rectangular shape as viewed from the light irradiation direction and the first connection electrode is exposed by the first electrode window formed in each of two corner portions of the frame body and further the first and second connection electrodes are exposed by four second electrode windows formed in four corner portions of the window cover, the package can protect the LED chip from environment and luminous efficiency can be increased and one can easily perform connection work to electrically connect a plurality of packages together. 
     In an embodiment, the window cover is provided with a microstructural optical element, which controls distribution of light radiated from the LED chip. In this configuration, because the window cover is provided with a microstructural optical element, which controls distribution of light radiated from the LED chip, the distribution of light can be controlled with only the package. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will now be described in further details. Other features and advantages of the present invention will become better understood with regard to the following detailed description and accompanying drawings where: 
         FIGS. 1A and 1B  show an Embodiment 1 of the present invention, and 
         FIG. 1A  is a perspective view, and  FIG. 1B  is an exploded perspective view; 
         FIG. 2  is a cross-section view of  FIG. 1A  along a line X-X; and 
         FIGS. 3A and 3B  show an Embodiment 2 of the present invention, and  FIG. 3A  is a perspective view, and  FIG. 3B  is an exploded perspective view. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Embodiment 1 
     As shown in  FIGS. 1A and 1B , a light emitting diode of the present embodiment comprises a light emitting diode chip (LED chip)  2  having high brightness, a package  1  in which the LED chip  2  is housed, and first and second connection electrodes  44 ,  45 . The package  1  is a three-layered laminated body comprising a submount substrate  10 , a frame body  20  and a window cover  30 . The package  1  is formed into a rectangular shape (a square shape in figures) as viewed from the front (as viewed from the light irradiation direction, that is, as viewed from an upper side in  FIG. 1A ). The package  1  has a configuration explained below, and thereby can be formed into equal to or less than 3 mm-square as viewed from the front, and thickness thereof can be set to be about 1 mm. 
     The frame body  20  is provided with a storage hole  22  as a through-hole penetrated in the front and back direction. The window cover  30  is laminated on the submount substrate  10  via the frame body  20 , and then the submount substrate  10 , the frame body  20  and the window cover  30  are secured together, and thereby the storage hole  22  is sealed hermetically. That is, the storage hole  22  is surrounded by the submount substrate  10 , the frame body  20  and the window cover  30 , and thereby an air proof space is formed. 
     The LED chip  2  is secured on the submount substrate  10  and is housed in the storage hole  22 , and thereby, is housed in the air proof space. Then, the air proof space is not only sealed but also may enclose inert gas or may be depressurized to come into near-vacuum. That is, the LED chip  2  can be protected without potting a synthetic resin and it becomes easy to ensure efficiency of light irradiation. 
     The submount substrate  10  comprises bonding layers  12 ,  13  and a base material  11 , which is formed by using an insulating material into a rectangular shape as viewed from the front. The bonding layers  12 ,  13  are formed of conductive metallic thin films, and are located on both end faces in a thickness direction of the base material  11 , respectively, as shown in  FIG. 2 . Further, as shown in  FIGS. 1B and 2 , the base material  11  is provided on its one surface with a bonding layer  14  formed into a circular ring. In addition, the one surface of the base material  11  is one end face of both end faces in its thickness direction, which faces the frame body  20 . That is, it is one end face facing toward the light irradiation direction. 
     The base material  11  has about the same linear expansion coefficient as the LED chip  2 , and is made of an insulating material having a relatively high heat conductivity. Materials meeting such a condition are AlN (Aluminum Nitride), SiC (Silicon Carbide) and diamonds. However, it is desirable to adopt AlN from a cost-effectiveness standpoint. Then, for example, the bonding layers  12 ,  13  are made of Au and the bonding layer  14  is made of AuSn. The bonding layers  12 ,  13  are formed in the front and back of the base material  11 , respectively, and are electrically insulated from each other. 
     As shown in  FIGS. 1 and 2 , the frame body  20  comprises a base material  21  formed by using an insulating material into a rectangular shape as viewed from the front. The base material  21  is provided in its central part with the storage hole  22 , which opens with a circular shape. Then, as shown in  FIGS. 1A and 1B , fan-shape notches as viewed from the front are put in adjacent two corner portions of four corner portions in the base material  21 , and thereby two first electrode windows  23  are formed. An inner periphery face of the storage hole  22  has an inclined surface  24 , which is formed into a tapered shape so that an inner diameter thereof gradually increases toward the light irradiation direction from the submount substrate  10 . 
     As shown in  FIG. 2 , the base material  21  is provided on both end faces in its thickness direction with bonding layers  25 ,  26 , which are formed of conductive metallic thin films, respectively. Then, the bonding layer  26  is formed on one end face of said both end faces, facing the submount substrate  10  (that is, one end face facing toward the direction opposite to the light irradiation direction), into a circular ring so as to be bonded to the bonding layer  14  in the submount substrate  10 . However, the shape of the bonding layer  26  is not limited to the circular ring, and the bonding layer  26  may be formed over a whole surface of said one end face. Then, the bonding layer  25  is formed on the other end face of said both end faces, facing the window cover  30  (that is, the other end face facing toward the light irradiation direction), and continues into a connecting pattern  25   a  formed on the inner periphery face of the storage hole  22 . That is, the connecting pattern  25   a  is made of the same material as the bonding layer  25 , and has conductive properties. 
     The base material  21  is made of the insulating material having heat resistance. However, the material of the base material  21  is not limited, as long as a there is little difference between linear expansion coefficients of the base material  21  and the submount substrate  10 . Then, for example, Al 2 O 3  can be selected as the material of the base material  21 . The bonding layer  26  is made of, for example, Au to be hermetically bonded to the bonding layer  14 . Then, the bonding layer  25  is also made of, for example, Au. However, the bonding layers  25 ,  26  in the front and back of the frame body  20  are electrically insulated from each other. 
     As shown in  FIGS. 1 and 2 , the window cover  30  comprises a base material  31 , which is transparent to a wave length of light radiated from the LED chip  2 . As shown in  FIGS. 1B and 2 , the base material  31  is provided on its one surface facing the frame body  20  with a bonding layer  32 , surrounding the storage hole  22 , formed into a circular ring. Then, fan-shape notches as viewed from the front are put in all four corner portions in the base material  31 , and thereby four second electrode windows  33  are formed. 
     If a luminous wavelength of the LED chip  2  is within a wavelength region (300 to 2500 nm) from a near-ultraviolet region to a far-infrared region, a borosilicate crown glass (BK7), which is an optical glass, is used for the base material  31 . Then, if the luminous wavelength is shorter than the near-ultraviolet region, a quartz glass is used for the base material  31 . Then, the bonding layer  32  is made of, for example, AuSn. 
     In the present embodiment, the submount substrate  10 , frame body  20  and the window cover  30  are basically bonded together automatically by Au—AuSn bonding. That is, Au is used for the bonding layer  26  of the frame body  20  and AuSn is used for the bonding layer  14  of the submount substrate  10 , and then the submount substrate  10  and the frame body  20  are bonded to each other by Au—AuSn bonding. Then, Au is used for the bonding layer  25  of the frame body  20  and AuSn is used for the boding layer  32  of the window cover  30 , and then the frame body  20  and window cover  30  are bonded to each other by Au—AuSn bonding. 
     In the Au—AuSn bonding, after bonding parts are aligned each other, the bonding parts are heated to an appropriate temperature (for example, 280 degrees C.). Then, AuSn is melt and thereby the bonding parts are bonded to each other. Here, the submount substrate  10  and the frame body  20  are not transparent to light. Therefore, when the submount substrate  10  and the frame body  20  are bonded to each other, these bonding parts are heated by using, for example, a heater (in this case, the bonding parts are heated before mounting the LED chip  2 ). On the other hand, the window cover  30  is transparent to light. Therefore, when the frame body  20  and the window cover  30  are bonded to each other, these bonding parts are heated by using, for example, a laser beam. 
     An ultraviolet light emitting diode, made of materials of GaN system, can be used for the LED chip  2  other than the infrared region and the visible region. Then, the LED chip  2  is provided on both end faces in its thickness direction with element electrodes  41 ,  42 , respectively. Specifically, as shown in  FIG. 2 , the LED chip  2  is provided on one end face of the both end faces with an anode (element electrode  41 ), and is provided on the other end face of the both end faces with two cathodes (element electrode  42 ). If the LED chip  2  irradiates ultraviolet and the package is made of a synthetic resin, the package easily deteriorates. On the other hand, the package  1  of the present embodiment is made of an inorganic material. Therefore, the deterioration due to the ultraviolet is inhibited and the light emitting diode can have a longer life. Then, the LED chip  2  is sealed in the air proof space, and the potting is not used. Thus, just like use of the inorganic material, the deterioration due to the ultraviolet is inhibited and the light emitting diode can have a longer life. 
     The LED chip  2  is installed fixedly on the submount substrate  10  and die bonding is performed, when mounted in the package  1 . The anode (element electrode  41 ) of the LED chip  2  is bonded to the bonding layer  12  of the submount substrate  10  upon the die bonding. 
     On the other hand, the two cathodes (element electrode  42 ) of the LED chip  2  are electrically connected to the connecting pattern  25   a  formed on the inner periphery face of the storage hole  22  via wires  43  for wire bonding. Then, as shown in  FIG. 1B , it is desirable that bonding recesses  27  are formed in two places of the inclined surface  24  and one ends of the wires  43  are bonded to the bonding recesses  27 , respectively. Each of the bonding recesses  27  is provided in its inner periphery face with a pedestal surface (not shown), which is formed in parallel to one surface of the frame body  20  facing the submount substrate  10 . Then, the wires  43  are bonded to the pedestal surfaces of the bonding recesses  27 , respectively. The connecting pattern  25   a  is formed so as to extend onto the pedestal surfaces. That is, when the LED chip  2  is mounted on the submount substrate  10  by the die bonding and the frame body  20  is bonded to the submount substrate  10 , both ends of each wire  43  can be bonded to the LED chip  2  and the frame body  20  with the force acting in the same direction, respectively. As a result, good workability can be ensured in assembling. 
     Then, the inclined surface  24  of the storage hole  22  is formed so that an inner diameter thereof gradually increases toward the light irradiation direction. Thereby, when bonding the two cathodes (element electrode  42 ) of the LED chip  2  to the connecting pattern  25   a  through the wires  43 , a working space for the wire bonding can be ensured relatively widely. Thus, good workability can be ensured. 
     Furthermore, the inclined surface  24  is covered with the connecting pattern  25   a  made of metal, and thereby light radiated from a periphery of the LED chip  2  is reflected by the inclined surface  24  and is radiated toward the window cover  30 . That is, in addition to light radiated from one end face facing the window cover  30 , light radiated from the periphery is also radiated toward the window cover  30 . 
     The window cover  30  may be provided in at least one end face of both end faces in its thickness direction with a optical element, which comprises a microstructural convexoconcave formed into a groove, a cone, a dome, etc. Here, the optical element is located in at least a region facing the storage hole  22  in at least one end face of said both end faces. That is, the window cover  30  comprises a lot of micro lenses, micro prisms, gratings, etc. as the optical element, and thereby distribution of light from the LED chip  2  may be controlled. 
     As described above, the window cover  30  is provided with the four second electrode windows  33  in four corner portions. The frame body  20  is provided with the two first electrode windows  23  in adjacent two corner portions of four corner portions. Then, the bonding layer  25  is formed in one end face of both end faces in the thickness direction of the frame body  20 , facing the window cover  30 . Then, the bonding layer  25  is partly exposed on the outside of the package  1 . At this time, as shown in  FIG. 1A , the bonding layer  25  is partly exposed in the light irradiation direction through two second electrode windows  33  of the window cover  30 . Furthermore, the bonding layer  25  is electrically connected to the LED chip  2  in the inner periphery face of the storage hole  22 . As a result, parts of the bonding layer  25 , exposed through the second electrode windows  33 , function as the second connection electrodes  45  electrically connected to the element electrodes  42 , which are the two cathodes of the LED chip  2 . 
     The remaining two second electrode windows  33  of the window cover  30  coincide with the two first electrode windows  23  of the frame body  20 , respectively. The bonding layer  12  is formed on one end face of both end faces in a thickness direction of the submount substrate  10 , facing the frame body  20 . Then, the bonding layer  12  is partly exposed on the outside of the package  1 . At this time, as shown in  FIG. 1A , the bonding layer  12  is partly exposed in the light irradiation direction through the remaining two second electrode windows  33  of the window cover  30  and the two first electrode windows  23  of the frame body  20 . The bonding layer  12  is bonded to the element electrode  41 , which is the anode of the LED chip  2 , by the die bonding. As a result, parts of the bonding layer  12 , exposed through the two first electrode windows  23 , function as the first connection electrodes  44  electrically connected to the element electrode  41 , which is the anode of the LED chip  2 . 
     As explained above, the LED chip  2  is sealed and airproofed in the package  1 , and the first and second connection electrodes  44 ,  45  are exposed in the light irradiation direction in the package  1 . Then, the bonding layer  13  is formed on the other end face of both end faces in the thickness direction of the submount substrate  10 , facing toward a direction opposite to the light irradiation direction. Therefore, the bonding layer  13  is bonded to a heat dissipation member (not shown) made of metal, such as Cu or Al, and thereby a path for heat dissipation can be ensured. 
     Here, in order to improve airtightness of bonding parts of the submount substrate  10 , the frame body  20  and the window cover  30  constituting the package  1 , these mutually-bonded members are required to have flat and smooth surfaces. In the present embodiment, materials, such as AlN, Al 2 O 3  and BK7, used for base materials of these bonded members, meet the above-mentioned requirement, and thus high airtightness can be ensured. 
     In addition, the submount substrate  10  and the frame body  20  of the present embodiment are formed of individual members differing from each other, respectively. However, for example, these may be integrally formed of one common member. In this regard, it is easier to polish surfaces in a case where the storage hole  22  is penetrated in a platy member like the present embodiment than in a case where a recess corresponding to the storage hole  22  is previously formed in the one common member. Thus, flat and smooth surfaces can be ensured easily. 
     The bonding layer  13  and the heat dissipation member of the package  1  are bonded to each other by using a bonding material, such as a slack wax (for example, a solder), a metal paste (for example, a silver paste), etc. which is liquid upon bonding and becomes hardened after bonding. The bonding can be performed so as not to form an air space between one face of the package  1  and the heat dissipation member by using such a bonding material. In addition, such a bonding material has a relatively high heat conductivity, and then can conduct heat from generally a whole area of the one face of the package  1  to the heat dissipation member. Thus, efficiency of heat dissipation can be improved. 
     Here, the bonding layer  13  and the LED chip  2  are electrically insulated from each other. Therefore, the bonding material having a high heat conductivity (typically, this kind of bonding material also has a high electrical conductivity) can be used without electrically insulating the heat dissipation member from the package  1 . Thus the bonding material can improve heat conduction from the package  1  to the heat dissipation member. Then, the first and second connection electrodes  44 ,  45  are located within a projection plane when the package  1  is viewed from the light irradiation direction. Thus, a plurality of packages  1  can be arranged without space between adjacent packages  1 , when being mounted on the heat dissipation member. That is, the density of LED placement can be improved, and a light source having high brightness can be provided. 
     In addition, the first and second connection electrodes  44 ,  45  are exposed on the front, and each of the first and second connection electrodes  44 ,  45  comprises two electrodes having the same polarity each other. Thus, if angles of a plurality of packages  1  are adjusted in being arranged, it becomes easy to identify polarity of the electrode. Thus, it becomes easy to perform connection work to electrically connect the plurality of packages  1  together. In electrically connecting the plurality of packages  1 , there are available various technologies, such as wire bonding technology with Au-wire or Al-wire, solder bonding technology with connecting wire, pressed contact technology to elastically connect a connecting conductor secured in the heat dissipation member with the first and second connection electrodes  44 ,  45 , etc. In addition, the plurality of packages  1  can be connected to a power source individually, and then can be connected in series or in parallel. 
     By the way, the package  1  is made of an inorganic material and the heat dissipation member is made of metal. Thus, there is a relatively-large difference between linear expansion coefficients of the package  1  and the heat dissipation member. However, the package  1  is bonded to the heat dissipation member through a whole surface of its one side, and then a bonding surface of the package  1  is formed into equal to or less than 3 mm-square. Therefore, the bonding intensity and the strength of the package  1  can be increased sufficiently with respect to a stress depending on the difference between the linear expansion coefficients. As a result, such a configuration can prevent a bonding part from coming unglued, and can prevent the package  1  from being damaged. 
     Embodiment 2 
     As shown in  FIGS. 3A and 3B , the frame body  20  of the present embodiment is formed by lamination of a plurality of sheeted frame boards  20   a  (four frame boards is shown in figures). Each frame board  20   a  is provided in its central part with a hole  22   a  penetrated in the front and back direction. Then, the storage hole  22  is formed by superposition of a plurality holes  22   a  associated with lamination of the plurality of frame boards  20   a . Each frame board  20   a  that doesn&#39;t include one frame board  20   a  has the hole  22   a  penetrated into a circular-shape. On the other hand, said one frame board  20   a  has the hole  22   a  penetrated into generally a D-shape, like a circle cut off by a chord, as shown in  FIG. 3B . 
     Furthermore, the plurality of holes  22   a  have a different diameter. A frame board  20   a  laminated directly on the submount substrate  10  is provided with the hole  22   a  having the smallest diameter, and then the remaining frame boards  20   a  are laminated so that diameters of the holes  22   a  increase in sequence. Therefore, the inner periphery face of the storage hole  22  is formed into not a tapered shape but a stepped shape, and then a diameter thereof gradually increases toward the window cover  30  from the submount substrate  10 . Then, as shown in  FIG. 3B , the D-shaped frame board  20   a  comprises a connection piece  29  partly projecting from the inner periphery face of the storage hole  22 . 
     Each of the plurality of frame boards  20   a  is provided on both end faces in its thickness direction with bonding layers (not shown) of metallic thin films, respectively. Then, adjacent frame boards  20   a  are bonded to each other through the bonding layers, and thereby the plurality of frame boards  20   a  are bonded together and sealed hermetically. Then, in these bonding layers, the metallic thin films (for example, Au) having high electrical conductivity are used for at least bonding layers formed in the frame board  20   a  comprising the connection piece  29 . That is, a connecting pattern (not shown) continuing into the bonding layer is formed on the connection piece  29 . In addition, as shown in  FIG. 3B , the frame board  20   a  comprising the connection piece  29  is located next to the frame board  20   a  contacting with the window cover  30 . 
     By the way, an outer periphery of the frame board  20   a  touching the window cover  30  has the same size and the same shape as that of the window cover  30 . That is, this frame board  20   a  has the first electrode windows  23   a  in all of four corner portions like the window cover  30 . On the other hand, subsequent frame boards  20   a  have the first electrode windows  23   a  in only adjacent two corner portions of four corner portions like the frame body  20  of the Embodiment 1. Therefore, the bonding layer formed in second top frame board  20   a  is partly exposed on the outside of the package  1  through the first electrode windows  23   a  of first top frame board  20   a  and the second electrode windows  33  of the window cover  30 , and functions as the second connection electrode  45 . 
     On the other hand, one end of each wire  43  is connected to the cathode (element electrode  42 ) of the LED chip  2 , and the other of each wire  43  is bonded to the connection piece  29 . That is, the second connection electrode  45  is electrically connected to the cathode (element electrode  42 ) of the LED chip  2 . Then, the storage hole  22  is provided in its inner periphery face with the connection piece  29  projecting. Therefore, a site, to which one end of each wire  43  is bonded, can have a relatively-large area. Furthermore, a surface of the site, to which one end of each wire  43  is bonded, is parallel to a surface of the submount substrate  10 , and thereby the one end of each wire  43  can be bonded to the site from the same direction. As a result, the bonding operation of wires  43  can be easily performed. 
     Then, because the second connection electrode  45  is located in second top frame board  20   a  of the frame body  20 , the bonding layer  25  bonded to the window cover  30  should be formed into a circular ring in the frame body  20 . Other configuration and function be no different from the Embodiment 1. In addition, the above-mentioned material is cited as one example about each member. For example, Al can be used instead of Au, and AnAgCu can be used instead of AuSn. Then, a foundation layer may be formed in a site constituting the Au thin film in order to prevent saturation of the base material. Then, Ni/Cu (when the base material is Al 2 O 3 ), Pt/Ti (when the base material is BK7), etc. can be used for the foundation layer in accordance with the base material. Then, the electrode window can be formed into a triangular-shape notch, a quadrangular-shape notch, etc. other than a fan-shape notch as described above. 
     basically, one LED chip  2  is housed in one package  1 . However, a plurality of LED chips  2  may be housed in one package  1 . Then, in the above configuration, the anode (element electrode  41 ) is bonded to the submount substrate  10 . However, the anode may be replaced with the cathode. 
     Although the present invention has been described with reference to certain preferred embodiments, numerous modifications and variations can be made by those skilled in the art without departing from the true spirit and scope of this invention, namely claims.