Patent Publication Number: US-2023160560-A1

Title: Substrate support body, substrate support structure, light emitting device, and lighting fixture

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application of International Application No. PCT/JP2021/016552, filed on Apr. 23, 2021, which designates the United States, the entire contents of which are herein incorporated by reference, and which is based upon and claims the benefit of priority to Japanese Patent Application No. 2020-078378, filed on Apr. 27, 2020, the entire contents of which are herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a substrate support body, a substrate support structure, a light emitting device and a lighting fixture. 
     BACKGROUND OF INVENTION 
     In recent years, a Light Emitting Diode (LED) has been used in a headlamp of an automobile. In this case, a structure has been proposed in which a plurality of LEDs are mounted on a wiring substrate in order to increase the amount of light (see, for example, Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2015-103714 A 
       
    
     SUMMARY 
     A substrate support body of the present disclosure includes a support plate, an enclosure member, and a bonding material. The enclosure member is arranged in a central region of the support plate. The bonding material is arranged on an entire surface of an inner region of the enclosure member and is bonded to the support plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an exploded perspective view of a substrate support structure according to an embodiment. 
         FIG.  2    is a plan view of the substrate support structure illustrated in  FIG.  1   . 
         FIG.  3    is a cross-sectional view taken along line iii-iii of  FIG.  1   . 
         FIG.  4    is a cross-sectional view illustrating another aspect of the substrate support structure. 
         FIG.  5    is a cross-sectional view illustrating another aspect of the substrate support structure. 
         FIG.  6    is a cross-sectional view illustrating another aspect of the substrate support structure. 
         FIG.  7    is a plan view of the substrate support structure illustrated in  FIG.  6    as viewed from a direction facing a surface of the substrate support structure on which the element mounting substrate is arranged. 
         FIG.  8    is an exploded perspective view illustrating another aspect of the substrate support structure. 
         FIG.  9    is a plan view of the substrate support structure illustrated in  FIG.  8   . 
         FIG.  10    is a cross-sectional view taken along a line x-x in  FIG.  8   . 
         FIG.  11    is a cross-sectional view illustrating another aspect of the substrate support structure. 
         FIG.  12    is a cross-sectional view illustrating another aspect of the substrate support structure. 
         FIG.  13    is a cross-sectional view of a light emitting device illustrated as an example of the embodiment. 
         FIG.  14    is a cross-sectional view of a lighting fixture illustrated as an example of the embodiment. 
         FIG.  15    is a cross-sectional view illustrating a manufacturing method for a substrate support body illustrated as an example of the embodiment. 
         FIG.  16    is a cross-sectional view illustrating a state in which an enclosure member having a chevron cross-sectional shape is formed. 
         FIG.  17    is a cross-sectional view illustrating a method for determining the degree of parallelism of the substrate support structure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     With respect to the light emitting device disclosed in Patent Literature 1, improvement is demanded for the heat dissipation from the substrate on which the light emitting element is mounted, as compared with a known case. The present applicant proposes a structure in which, when a substrate on which a plurality of light emitting elements are mounted is bonded to a support plate, the substrate bonded to the support plate can be arranged in a more stable state in addition to improving heat dissipation from the support plate. Hereinafter, the substrate is referred to as a substrate support body. 
     A substrate support structure and a light emitting device according to an embodiment will be described with reference to  FIGS.  1  to  6   . Note that an aspect of the present invention is not limited to the particular embodiment to be described below. The aspect of the present invention includes various aspects insofar as these aspects fall within the spirit or scope of the general concepts of the invention as defined by the appended claims. 
       FIG.  1    is an exploded perspective view of the substrate support structure illustrated as an example of the embodiment.  FIG.  2    is a plan view of the substrate support structure illustrated in  FIG.  1   .  FIG.  3    is a cross-sectional view taken along line iii-iii of  FIG.  1   . In  FIG.  2   , an enclosure member  3  is a frame-like portion that is between two rectangular portions indicated by dashed lines. 
     A bonding material  5  is a rectangular portion indicated by a dotted line arranged inside the enclosure member  3 . An element mounting substrate  7  is a solid rectangular portion larger than the enclosure member  3 .  FIG.  2    illustrates a state in which a gap is provided between the enclosure member  3  and the bonding material  5 . Such an illustration is for ease of understanding of the enclosure member  3  and the bonding material  5  on the drawings. 
     A substrate support structure A illustrated as the example of the embodiment includes at least a support plate  1 , the enclosure member  3 , and the bonding material  5 . In the substrate support structure A, a portion constituted by the support plate  1 , the enclosure member  3 , and the bonding material  5  is the substrate support body. In  FIG.  1   , a portion of the substrate support body is indicated by reference sign A 1 . 
     The support plate  1  is made of metal. The metal material includes a material containing one kind selected from aluminum, copper, brass and the like as a main component. The support plate  1  may be a clad material obtained by bonding an aluminum foil and a copper foil. The enclosure member  3  is made of an organic resin. The bonding material  5  is a low melting point metal represented by solder, Au—Sn, and silver solder. 
     The enclosure member  3  is arranged in a central region  1   aa  of the support plate  1 . Here, the central region  1   aa  of the support plate  1  is the central region  1   aa  in a main surface  1   a  of the support plate  1 , as illustrated in  FIG.  2   . The enclosure member  3  is in a state of protruding from the main surface  1   a . The state of protruding from the main surface  1   a  means a state of protruding from a surface on which the enclosure member  3  is installed. 
     As illustrated in  FIGS.  1  and  2   , the enclosure member  3  may have a rectangular outer peripheral edge. The shape of the enclosure member  3  may not be rectangular depending on the application of the light emitting device to be described below. For example, the shape may be circular, elliptical, polygonal having more corners than a rectangular, or the like. 
     The shape of the enclosure member  3  is a shape in which the vicinity of the center of an inner region  3   a  of the enclosure member  3  is a centroid. The enclosure member  3  is line-symmetric in a planar shape. The bonding material  5  is arranged on an entire surface of the inner region  3   a  of the enclosure member  3 . 
     A substrate support body A 1  has a configuration in which the enclosure member  3  is arranged on the support plate  1  and the bonding material  5  is arranged on the entire surface of the inner region  3   a  of the enclosure member  3 . Therefore, the surface area and the shape of the bonding material  5  can be fixed. In this manner, for example, the element mounting substrate  7  for mounting the light emitting element can be arranged on the bonding material  5  more parallel to the support plate  1  and stably at a predetermined position. 
     The stable arrangement at a predetermined position means that the element mounting substrate  7  can be arranged at a desired position on the support plate  1 . A ceramic substrate is used as the element mounting substrate  7 . In this case, a surface area of a main surface of the element mounting substrate  7  is greater than a surface area of a region surrounded by an outer peripheral edge of the enclosure member  3 . 
     The ceramic substrate has a high thermal resistance, a high mechanical strength, and a property that its coefficient of thermal expansion is close to that of the material of the light emitting element to be described below. The material of the ceramic substrate is a material containing one kind selected from the group consisting of alumina, glass ceramics, silicon nitride, aluminum nitride, mullite, forsterite, enstatite and cordierite as a main component. Among them, silicon nitride is particularly preferable in terms of thermal resistance and mechanical strength. 
     On the surface of the element mounting substrate  7  to be bonded to the bonding material  5 , a metallized film is formed in advance for the purpose of enhancing the wettability with the bonding material  5 . The metallized film is a metallized film of copper. The metallized film of copper is preferably formed by plating films of nickel, gold, and tin in this order. 
       FIG.  4    is a cross-sectional view illustrating another aspect of the substrate support structure. In the case of a substrate support structure B illustrated in  FIG.  4   , because many reference signs are given in  FIG.  4   , the element mounting substrate  7  is omitted for convenience. Also in this case, it goes without saying that the element mounting substrate  7  is arranged as in the case of the substrate support structure A. In  FIG.  4   , a portion of the substrate support body is designated B 1 . 
     In the substrate support body B 1  illustrated in  FIG.  4   , a height h of the enclosure member  3  and a thickness t of the bonding material  5  are different from each other. The upper surface of the enclosure member  3  is lower than the upper surface of the bonding material  5 . In other words, the height h of the enclosure member  3  is less than the thickness t of the bonding material  5 . As a result, when the element mounting substrate  7  is placed on the bonding material  5 , the bonding material  5  tends to spread around the enclosure member  3  due to the applied pressure. 
     Therefore, according to the configuration of the substrate support body B 1 , the parallelism of the bonding material  5  can be enhanced. As illustrated in  FIG.  4   , the height h of the enclosure member  3  is a distance from the main surface  1   a  of the support plate  1  to an apex portion  3   b  of the enclosure member  3 . In the case of the enclosure member  3  illustrated in  FIG.  4   , because the upper surface is flat, the apex portion  3   b  of the enclosure member  3  is a height up to the flat surface. 
       FIG.  5    is a cross-sectional view illustrating another aspect of the substrate support structure.  FIG.  5    illustrates a substrate support structure C. Also in the case of the substrate support structure C illustrated in  FIG.  5   , because many reference signs are given in  FIG.  5   , the element mounting substrate  7  is omitted for convenience. Also in this case, it goes without saying that the element mounting substrate  7  is arranged as in the case of the substrate support structure A. In  FIG.  5   , a portion of the substrate support body is designated C 1 . 
     In the substrate support structure C, when the enclosure member  3  has a convex shape as illustrated in  FIG.  5   , the upper surface of the enclosure member  3  is an apex portion of the convex shape. As illustrated in  FIG.  2   , the enclosure member  3  is formed in a circling shape on the main surface  1   a  of the support plate  1 . When the enclosure member  3  has a circling shape, the height h of the enclosure member  3  from the support plate  1  is lower than the position of the upper surface  5   a  of the bonding material  5  at a rate of 80% or more upon setting the total length of the circling length of the enclosure member  3  to  100 . 
     When a relationship between the height h of the enclosure member  3  from the support plate  1  and the position of the upper surface  5   a  of the bonding material  5  is specifically measured, for example, one place is designated from each side of the enclosure member  3  to select a place to be measured. Then, a photograph of a cross section of the one place is taken, and the presence or absence of a difference between the height h of the enclosure member  3  from the support plate  1  and the position of the upper surface  5   a  of the bonding material  5  is evaluated from the taken photograph. 
     In this case, a difference d between the height h of the enclosure member  3  and the thickness t of the bonding material  5  is 30 μm or less. Here, the difference d is a dimensional difference. The difference d between the height h of the enclosure member  3  and the thickness t of the bonding material  5  corresponds to a difference d between the position of the apex portion  3   b  of the enclosure member  3  with respect to the main surface  1   a  of the support plate  1  and the position of the upper surface  5   a  of the bonding material  5 . 
     When the difference d between the height h of the enclosure member  3  and the thickness t of the bonding material  5  is 30 μm or less, the amount of deformation when the bonding material  5  is pressurized can be reduced. In this case, the difference d between the height h of the enclosure member  3  and the thickness t of the bonding material  5  is 5 μm or more because the bonding material  5  easily spreads around the enclosure member  3  by pressurization and the filling rate of the bonding material  5  into the inner region  3   a  of the enclosure member  3  can be increased. 
     When the difference d between the height h of the enclosure member  3  and the thickness t of the bonding material  5  is determined, the height h of the enclosure member  3  and the thickness t of the bonding material  5  are measured from the photograph obtained by photographing the cross section of the enclosure member  3  as described above, and the difference d is determined from these values. 
     As illustrated in  FIGS.  4  and  5   , the bonding material  5  is in contact with a portion from a side surface  3   c  facing the inner region  3   a  of the enclosure member  3  to the apex portion  3   b  of the enclosure member  3 . As a result, the bonding material  5  is easily spread in contact with the side surface  3   c  of the enclosure member  3  when the bonding material  5  spreads around the enclosure member  3  due to the pressure applied. 
     In a state where the bonding material  5  is in contact with a portion from the side surface  3   c  facing the inner region  3   a  of the enclosure member  3  to the apex portion  3   b  of the enclosure member  3 , a friction force is likely to act between the side surface  3   c  as well as the apex portion  3   b  of the enclosure member  3  and the bonding material  5 . This causes the speed of spread of the bonding material  5  to be slow. This also makes it easy to control the spreading speed and spreading area of the bonding material  5 . As a result, the parallelism of the bonding material  5  with respect to the main surface  1   a  of the support plate  1  can be further enhanced. 
     As illustrated in  FIG.  5   , a portion of the enclosure member  3  from the side surface  3   c  facing the inner region  3   a  to the apex portion  3   b  forms a convex curved surface. In a structure in which the portion from the side surface  3   c  to the apex portion  3   b  of the enclosure member  3  has a shape forming a convex curved surface, the bonding material  5  easily spreads smoothly around the enclosure member  3  without resistance from the beginning due to the pressure applied, for example, as compared with the case where the portion from the side surface  3   c  to the apex portion  3   b  of the enclosure member  3  has a step. 
     This facilitates the control of the surface area of the spreading bonding material  5 . This also makes it possible to make the surface area of the bonding material  5  spreading around the enclosure member  3  approximately the same in all directions. As a result, the parallelism between the upper surface  5   a  of the bonding material  5  and the main surface  1   a  of the support plate  1  can be enhanced. In this manner, the deviation of the heat dissipation due to the influence of the spread of the bonding material  5  can be reduced. In this case, as illustrated in  FIG.  5   , the enclosure member  3  has a chevron shape in cross section. In particular, the side surface  3   c  is in the form of a convexly bulging chevron. 
     The elastic modulus of the enclosure member  3  is less than the elastic modulus of the bonding material  5 . Accordingly, even when the bonding material  5  is less likely to be deformed by the applied pressure, the enclosure member  3  is more likely to be deformed, and thus a crack is less likely to occur in the bonding material  5 . As a result, a mechanically highly reliable substrate support structure can be obtained. 
       FIG.  6    is a cross-sectional view illustrating another aspect of the substrate support structure.  FIG.  7    is a plan view of a substrate support structure D illustrated in  FIG.  6    as viewed from a direction facing a surface of the substrate support structure D on which the element mounting substrate is arranged. In  FIG.  6   , a portion of the substrate support body is designated D 1 . In the substrate support structure D illustrated in  FIGS.  6  and  7   , the element mounting substrate  7  includes a mounting portion  9  for the light emitting element at an upper surface  7   a  of the element mounting substrate  7 . 
     As illustrated in  FIG.  7   , the mounting portion  9  is arranged in a center portion  7   b  of the upper surface  7   a  of the element mounting substrate  7 . Here, the center portion  7   b  of the element mounting substrate  7  is a region extending substantially uniformly from the position of the center (centroid) of the element mounting substrate  7  at a rate corresponding to the length of each side in the x direction and the y direction of the element mounting substrate  7 . As a guide for the surface area of the center portion  7   b  is a surface area corresponding to the product of half the length of the side of the element mounting substrate  7  in the x direction and half the length of the side of the element mounting substrate  7  in the y direction. 
     The mounting portion  9  includes a plurality of terminals  9   a .  FIG.  7    illustrates a case where the number of terminals  9   a  is six, but the number of terminals is not limited to six. For example, the number of terminals  9   a  may be eight or more. The number of terminals  9   a  varies depending on the required output power of the light emitting device, the size of the support plate  1 , and the like. However, in order to suppress the amount of heat generated from the light emitting device, the number of terminals  9   a  can be set to, for example, 100 or less. As illustrated in  FIG.  7   , the surface area of the mounting portion  9  on a surface (upper surface  7   a ) of the element mounting substrate  7  is less than the surface area of the bonding material  5  in a direction identical to a direction along the surface. 
     When the light emitting element is connected to each terminal  9   a  and driven, the region of the mounting portion  9  is present in the region of the bonding material  5 . Therefore, the deviation of the heat dissipation caused by driving of a plurality of light emitting elements can be reduced. As a result, a light emitting device having little difference in the amount of light between each of the light emitting elements can be obtained. When the mounting portion  9  is provided on the element mounting substrate  7 , wiring is provided on the upper surface  7   a  and/or an inner portion  7   c  of the element mounting substrate  7 . This wiring is connected to a power source. 
     In the substrate support structure D illustrated in  FIGS.  6  and  7   , the enclosure member  3  has a rectangular cross-sectional shape, but the enclosure member  3  can also have a chevron shape in cross section as illustrated in  FIG.  5   . 
       FIG.  8    is an exploded perspective view illustrating another aspect of the substrate support structure.  FIG.  9    is a plan view of a substrate support structure E illustrated in  FIG.  8   .  FIG.  10    is a cross-sectional view taken along a line x-x in  FIG.  8   . The substrate support structure E illustrated in  FIGS.  8 ,  9  and  10    has a frame member  11 . The substrate support structure E includes the frame member  11  on the support plate  1 . 
     The frame member  11  is arranged on a peripheral edge portion  1   c  of the support plate  1 . The frame member  11  is positioned around the enclosure member  3 , the bonding material  5 , and the element mounting substrate  7  that are arranged on the support plate  1 . The frame member  11  surrounds the enclosure member  3 , the bonding material  5 , and the element mounting substrate  7  that are arranged on the support plate  1 . According to the substrate support structure E, the frame member  11  is responsible for protecting the enclosure member  3 , the bonding material  5 , and the element mounting substrate  7  that are arranged in the region inside the frame member  11  on the support plate  1 . 
     For example, when the frame member  11  is provided on the support plate  1 , the enclosure member  3 , the bonding material  5 , and the element mounting substrate  7  can be protected from the physical harm from a direction facing a side surface  11   a  of the frame member  11 . The frame member  11  may be arranged such that the side surface  11   a  on the outside of the frame member  11  is arranged along a side surface  1   b  of the support plate  1 . The side surface  11   a  on the outside of the frame member  11  and the side surface  1   b  of the support plate  1  may be arranged to be flush with each other. 
     Although not illustrated, a lid may be bonded to the frame member  11 . The lid is installed on an upper surface  11   b  of the frame member  11 . The lid is bonded to the entire periphery of the upper surface  11   b  of the frame member  11 . When the lid is provided in the frame member  11 , the enclosure member  3 , the bonding material  5 , and the element mounting substrate  7  can be protected also from the physical harm from a direction facing the upper surface  11   b  of the frame member  11 . Furthermore, a space inside the frame member  11  on the support plate  1  can be hermetically sealed. 
       FIG.  11    is a cross-sectional view illustrating another aspect of the substrate support structure. A substrate support structure F illustrated in  FIG.  11    includes external electrodes  13  on the upper surface  11   b  of the frame member  11 . When the external electrodes  13  are provided on the upper surface  11   b  of the frame member  11 , electrical connection with the element mounting substrate  7  can be easily performed using, for example, bonding wires  15 . 
       FIG.  12    is a cross-sectional view illustrating another aspect of the substrate support structure. In a substrate support structure G illustrated in  FIG.  12   , a step portion S is provided on the upper surface  11   b  of the frame member  11 , and the external electrodes  13  are provided on the step portion S. In this case, the external electrode  13  may extend into the frame member  11  and may be integrated with inner layer wiring. The external electrode  13  and the inner layer wiring may be electrically connected via a connection portion. 
     According to the substrate support structure G, because the wire  15  connected to the element mounting substrate  7  is connected to the external electrode  13  provided in the step portion S of the frame member  11 , the position of the wire  15  can be lower than the position of the upper surface  11   b  of the frame member  11 . This makes it possible to protect the enclosure member  3 , the bonding material  5 , and the element mounting substrate  7 . This also makes it possible to minimize the possibility of the physical harm to the wire  15  from an object passing through the upper surface  11   b  of the frame member  11 . 
     As the enclosure member  3  of each of the substrate support structures E, F, and G provided with the frame member  11 , the enclosure member  3  having a rectangular cross section is illustrated as an example. However, the enclosure member  3  having a chevron cross section illustrated in  FIG.  5    can also be applied to the enclosure member  3  of each of the substrate support structures E, F, and G. 
       FIG.  13    is a cross-sectional view of a light emitting device illustrated as an example of the embodiment. A light emitting device H illustrated in  FIG.  13    has a structure in which the substrate support structure A illustrated in  FIGS.  1  to  3    is applied as the substrate support structure, but the substrate support structures B to G described above can also be applied as the substrate support structure. 
     In the light emitting device H illustrated in  FIG.  13   , light emitting elements  17  are arranged on the mounting portion  9  of the element mounting substrate  7  included in the substrate support structure A. In this case, the mounting portion  9  includes a plurality of the light emitting elements  17 . The plurality of light emitting elements  17  are mounted on the mounting portion  9  of the element mounting substrate  7 . According to the light emitting device H, light can be emitted in a direction as designed from an electronic device in which the light emitting device H is installed. 
       FIG.  14    is a cross-sectional view of a light fixture illustrated as an example of the embodiment. A lighting fixture J includes the light emitting device H as a light source portion  21 . The light source portion  21  has a configuration in which the light emitting device H is provided with a lid  22 . The lid  22  is formed of a translucent member. The translucent member is preferably made of glass, ceramic, or the like in terms of light transparency and thermal resistance. 
     The light source portion  21  is provided inside a casing  23 . The casing  23  includes a light transmission portion  25 . The light transmission portion  25  is arranged facing the direction in which light  27  emitted from the light source portion  21  travels. The lighting fixture J illustrated in  FIG.  14    is assumed to be lighting equipment, a headlamp for an automobile, or the like. For example, when the light emitting device H is installed in an electronic device such as a headlamp, the support plate  1  included in the substrate support structure A is fixed to a base  29  attached to the casing  23  of the headlamp (lighting fixture J) by a fixing jig  30 . 
     In the light emitting device H, when the element mounting substrate  7  on which the light emitting elements  17  are mounted is not parallel to the base  29  attached to the casing  23 , the traveling direction of the light  27  deviates from the set direction. On the other hand, the substrate support structures A to G and the light emitting device H described above can be installed such that the element mounting substrate  7  on which the light emitting elements  17  are mounted is parallel to the support plate  1 . 
     In the case of the substrate support structures A to G and the light emitting device H, when the support plate  1  is fixed along the surface  29   a  of the base  29  attached to the casing  23 , the element mounting substrate  7  is parallel to a surface  23   a  of the base  29  attached to the casing  23 . In this manner, the traveling direction of the light  27  can be set at a right angle or an angle close to a right angle with respect to a surface  29   a  of the base  29  attached to the casing  23  of the headlamp (the lighting fixture J). 
     As a result, lighting fixture J with stable directionality of the light  27  can be obtained. According to the substrate support structures A to G, the light emitting device H, and the lighting fixture J that are described above, even when the plurality of light emitting elements  17  are mounted on the mounting portion  9  of the element mounting substrate  7 , any one of the substrate support structures A to G and the support plate  1  are bonded to each other by the bonding material  5  defined to have a surface area and a thickness as designed or close thereto, and thus heat generated from the plurality of light emitting elements  17  can be released from the substrate support structures A to G with little deviation. 
       FIG.  15    is a cross-sectional view illustrating a manufacturing method for a substrate support body illustrated as an example of the embodiment. The manufacturing method for the substrate support body illustrated in  FIG.  15    is an example in which the substrate support structure A illustrated in  FIGS.  1  to  3    is applied to the light emitting device H. As illustrated in  FIG.  15 A , first, a metal plate  31  serving as the support plate  1  is prepared. Next, a photosensitive resist film  33  is formed on one surface of the metal plate  31 . The resist film  33  is mainly composed of an epoxy resin. 
     Next, as illustrated in  FIG.  15 B , a mask  35  is placed on the upper surface of the resist film  33 , and exposure is performed from above the mask  35 . The mask  35  is made of either glass or an organic film. The mask  35  is of a type that allows light to pass through a portion where the resist film is to be cured. 
     Next, as illustrated in  FIG.  15 C , development processing is performed on the resist film  33  after exposure. This processing can leave a portion of the resist film  33  that is cured. A portion  37  that is cured becomes the enclosure member  3 . The cured part is referred to below as the cured portion  37 . The cured portion  37  is the enclosure member  3 . The enclosure member  3  formed by the method illustrated in  FIG.  15 C  has a rectangular cross section. A height of the cured portion  37  is adjusted by a thickness of the resist film  33 . A width of the cured portion  37  is adjusted by the size (width, surface area) of the portion through which the light passes formed in the mask. 
     Next, as illustrated in  FIG.  15 D , a bonding material sheet  39  is arranged between the cured portion  37  (enclosure member  3 ) formed on the metal plate  31 . In this case, the bonding material sheet  39  formed in advance as a film shape is used. The bonding material sheet  39  becomes the bonding material  5  after heating. If the bonding material sheet  39  processed into a film shape is used, the thickness of the bonding material sheet  39  can be easily adjusted to the height of the cured portion  37 . Furthermore, variation in the film thickness of the bonding material sheet  39  can be suppressed. 
     Next, as illustrated in  FIG.  15 E , the element mounting substrate  7  is placed on the upper surface of the cured portion  37  and the bonding material sheet  39 , and a pressure and heat treatment is performed under a predetermined temperature condition. As the element mounting substrate  7 , a substrate is used in which, on one surface of the element mounting substrate  7 , a metallized film of copper is first formed and then respective plating films of nickel, gold and tin are formed in this order. The copper metallized film formed on the element mounting substrate  7  is arranged in the central region of the surface of the element mounting substrate  7 . 
     The surface area of the copper metallized film formed on the element mounting substrate  7  corresponds to the surface area of the inner region  3   a  of the enclosure member  3  formed on the support plate  1 . Thus, the substrate support structure A can be prepared. When the frame member  11  is formed on the support plate  1 , the cured portion  37  of the resist film  33  serving as the enclosure member  3  is formed on the support plate  1 , and then the frame member  11  is bonded to the surface of the support plate  1  on which the cured portion  37  is formed. 
     As the frame member  11 , for example, an organic resin sheet containing an epoxy resin as a main component is also suitable. The organic resin sheet and the frame member  11  may be colored. In order to easily absorb light, a black color is preferable. In order to easily reflect light, a white color is preferable. The above-described method is also used when the substrate support structures B, and D to G are prepared. 
       FIG.  16    is a cross-sectional view illustrating a method of forming an enclosure member having a chevron cross-sectional shape. When the substrate support structure C having the enclosure member  3  having a chevron shape in cross section is prepared, as illustrated in  FIG.  16   , a method is used in which an organic resin material to be the enclosure member  3  is applied to the surface of the metal plate  31  to form a coating film  41 . 
     As a method for forming the coating film  41 , a screen printing method is used. Also in this case, the organic resin material contains an epoxy resin as a main component. The organic resin material having a viscosity adjusted to ink-like consistency is used. 
     The viscosity characteristic of the organic resin material includes thixotropic properties. When an organic resin material having thixotropic viscosity characteristics is used, the shape retention of the coating film  41  formed after printing is enhanced. In this manner, the enclosure member  3  having a chevron shape in cross section can be formed from the coating film  41 . The height of the coating film  41  is adjusted by, for example, an interval between the metal plate  31  and the printing screen. The width of the coating film  41  is adjusted by the size (width, surface area) of the opening in the printing screen. Other procedures except for the procedure of forming the coating film  41  to be the enclosure member  3  are roughly the same as those of the manufacturing method illustrated in  FIG.  15   . 
     Examples 
     Specifically, the substrate support bodies illustrated in  FIGS.  3 ,  4 ,  5 , and  6    were prepared and evaluated as described below. Sample 1 corresponds to the substrate support structure A illustrated in  FIG.  3   . Sample 1 was prepared so that the height of the enclosure member was equal to the thickness of the bonding material. Sample 2 corresponds to the substrate support structure B illustrated in  FIG.  4   . Sample 2 was prepared so that the height of the enclosure member was less than the thickness of the bonding material. 
     Sample 3 corresponds to the substrate support structure C illustrated in  FIG.  5   . Sample 3 was prepared so that the shape of the cross section of the enclosure member was a chevron shape and the height thereof was less than the thickness of the bonding material. Sample 4 corresponds to the substrate support structure D illustrated in  FIG.  6   . In Sample 4, the mounting portion was provided on the element mounting substrate. Sample 5 is a substrate support body prepared without installing an enclosure member. 
     Sample 1, Sample 2, and Sample 4 were prepared using the manufacturing method illustrated in  FIG.  15   . Sample 3 was prepared using the manufacturing method illustrated in  FIG.  16   . In Sample 2 and Sample 3, the difference between the height of the enclosure member and the thickness of the bonding material was 30 μm. In Sample 1 and Sample 4, the difference between the height of the enclosure member and the thickness of the bonding material was 5 μm. Aluminum plate was used as the support plate. As the element mounting substrate, a substrate made of silicon nitride was used in which, on one surface of the substrate, a copper metallized film was formed, and then plating films of nickel, gold, and tin were further formed in this order. 
     The copper metallized film formed on the element mounting substrate was arranged in the central region of the surface of the element mounting substrate. The surface area of the copper metallized film formed on the element mounting substrate was the same as the surface area of the inner region of the enclosure member formed on the support plate. Au—Sn was used as the bonding material. The elastic modulus at room temperature (25° C.) was about 1 GPa for the resist film (epoxy resin) used as the enclosure member, about 60 GPa for Au—Sn, and about 200 GPa for the element mounting substrate. 
     The samples were prepared by preparing a mother sample in which 25 samples were arranged in a matrix and cutting the mother sample into individual pieces. For each sample size, the support plate was 20 mm×30 mm and 0.5 mm thick. The width of the enclosure member was 1 mm. The length of the enclosure member was 50 mm for the entire circumference (10 mm+10 mm+15 mm+15 mm). 
     The size of the element mounting substrate was 15 mm×20 mm. The surface area of the mounting portion of the light emitting element formed on the upper surface of the element mounting substrate was 10 mm×15 mm. The light emitting elements were mounted on the mounting portion at a 5 mm pitch. The number of light emitting elements mounted on the mounting portion was six (two rows and three columns). 
     Next, the temperature of the surface of the element mounting substrate when a voltage was applied to the light emitting element for 1 minute was measured using a thermocouple. The number of samples used for evaluation was 10 in each case, and the average value was determined. The number of samples used for measuring the temperature of the surface of the element mounting substrate was one. In Table 1, “Surface temperature of element mounting substrate when light emitting elements are driven” is illustrated. In this case, the lower the surface temperature of the element mounting substrate is, the larger the amount of heat discharge from the element mounting substrate through the bonding material and the support plate is. 
     Next, the prepared samples were evaluated as illustrated in Table 1. First, the ratio of the wet area of the bonding material to the surface area of the copper metallized film formed on the element mounting substrate was determined. In Table 1, “Wet area of bonding material/surface area of copper metallized film” is illustrated. Next, the wet area of the bonding material was determined based on the surface area of the inner region of the enclosure member formed on the support plate. In Table 1, “Wet area of bonding material/surface area of inner region of enclosure member” is illustrated. 
     Here, the wet area is a surface area in which the bonding material (eutectic solder) adheres to the copper metallized film formed on the element mounting substrate. In Table 1, a negative value indicates that the wet area of the bonding material is less than the surface area of the copper metallized film. A positive value indicates that the wet area of the bonding material is greater than the surface area of the copper metallized film. A value of 0 indicates that the wet area of the bonding material is within 1% of the surface area of the copper metallized film. 
     The wet area was determined from the image obtained using the X-ray CT. Specifically, the X-Y direction of the copper metallized film formed on the element mounting substrate was photographed as a plane, and the ratio of the surface area to which the bonding material adhered to the surface area of the copper metallized film in the X-Y direction was calculated. 
     Next, the change in the thickness of the bonding material was determined. In this case, the change in the thicknesses of the bonding material corresponds to a ratio ((t2−t1)/t1), which is a ratio of the thicknesses t2 of the bonding materials after the substrate support structure is prepared to the thicknesses of the bonding material sheets used as a reference (t1). The thicknesses t2 of the bonding material after preparing the substrate support structure is obtained by measuring three portions existing in the inner region of the enclosure member. 
     The thickness of the bonding material was determined by polishing the cross section of the prepared substrate support structure, then taking a photograph of the cross section, and obtaining the thickness from the taken photograph. The digital microscope was used to capture photographs. The variation in the thickness of the bonding material was determined to be a value obtained by dividing the difference between the maximum value and the minimum value of the thickness obtained from the measured 10 samples by the average value. 
     The presence or absence of spreading of the bonding material from the range of the enclosure member was evaluated from the state of the surface of the element mounting substrate by observing the substrate support structure with the naked eye from a direction facing the side surface. In Table 1, the expression “Present (small)” indicates a state in which the width of the bonding material spread to the same extent as the width of the enclosure member. In Sample 5, although the enclosure member was not used, the state described as “Present (large)” is a state in which the width of the bonding material spread by 5 times or more the width of the enclosure member used in each of Samples 1 to 4. 
     In each of Sample 1 to Sample 4, the bonding material was in contact with a portion from the side surface facing the inner region of the enclosure member to the apex portion of the enclosure member. The presence or absence of a crack generated in the bonding material was also evaluated using X-ray CT. 
     The parallelism was determined from the difference of intervals between the support plate and the element mounting substrate by the method illustrated in  FIG.  17    for the prepared substrate support structure. The parallelism was determined to be higher as the difference between h1 and h2 (h1−h2) was closer to 0. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 Presence or 
                   
                   
                 Difference 
               
               
                   
                   
                 Wet area of 
                 Wet area of 
                   
                 absence of 
                   
                 Surface 
                 (parallelism) 
               
               
                   
                   
                 bonding 
                 bonding 
                   
                 spreading of 
                 Presence 
                 temperature of 
                 of intervals 
               
               
                   
                   
                 material/ 
                 material/ 
                 Change 
                 bonding 
                 or absence 
                 element mounting 
                 between 
               
               
                   
                   
                 surface area 
                 surface area 
                 rate of 
                 material 
                 of crack 
                 substrate when 
                 support plate 
               
               
                   
                   
                 of copper 
                 of inner region 
                 thickness 
                 from range of 
                 generated 
                 light emitting 
                 and element 
               
               
                 Sample 
                 Target 
                 metallized 
                 of enclosure 
                 of bonding 
                 enclosure 
                 in bonding 
                 elements are 
                 mounting 
               
               
                 number 
                 FIG. 
                 film 
                 member 
                 material 
                 member 
                 material 
                 driven 
                 substrate 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Sample 1 
                 FIG. 3 
                 0.92 
                 0.98 
                 −0.05 
                 Absent 
                 Absent 
                 110° C. 
                 0.8 μm 
               
               
                 Sample 2 
                 FIG. 4 
                 0.95 
                 1.06 
                 −0.05 
                 Present (small) 
                 Absent 
                 105° C. 
                 0.9 μm 
               
               
                 Sample 3 
                 FIG. 5 
                 0.95 
                 1.1 
                 −0.05 
                 Present (small) 
                 Absent 
                  95° C. 
                 1.0 μm 
               
               
                 Sample 4 
                 FIG. 6 
                 0.95 
                 1.06 
                 −0.05 
                 Present (small) 
                 Absent 
                  95° C. 
                 0.8 μm 
               
               
                 Sample 5 
                 — 
                 0.85 
                 1.3 
                 −0.3 
                 Present (large) 
                 Present 
                 112° C. 
                 1.9 μm 
               
               
                   
               
            
           
         
       
     
     As is clear from Table 1, in the samples (Samples 1 to 4) provided with the enclosure member, the ratio of the wet area of the bonding material to the surface area of the copper metallized film was large and the surface area where the bonding material wetted and adhered to the surface of the copper metallized film was large compared to the sample (Sample 5) not provided with the enclosure member. In addition, the ratio of the wet area of the bonding material to the surface area of the inner region of the enclosure member was small, and the bonding material was difficult to spread by the enclosure member. 
     In addition, the amount of change in the thickness of the bonding material with respect to the thickness of the bonding material sheet was small, and the system for the thickness of the bonding material was high. In addition, in Samples 1 to 4, no crack was observed in the bonding material. In addition, in Samples 1 to 4, the surface temperature of the element mounting substrate when the light emitting elements were driven was less than that of Sample 5. 
     In addition, in Sample 2 in which the height of the enclosure member from the support plate was lower than the position of the upper surface of the bonding material, both the ratio of the wet area of the bonding material to the surface area of the copper metallized film and the ratio of the wet area of the bonding material to the surface area of the inner region of the enclosure member were greater than those in Sample 1 in which the height of the enclosure member from the support plate was the same as and/or similar to the position of the upper surface of the bonding material. 
     In addition, the surface temperature of the element mounting substrate when the light emitting elements were driven was less in Sample 2 than in Sample 1. In addition, when the difference of the intervals between the support plate and the element mounting substrate was measured, the difference was 1.0 μm or less in Samples 1 to 4 but was as large as 1.9 μm in Sample 5. Samples 1 to 4 had greater parallelism than Sample 5. 
     REFERENCE SIGNS 
     
         
         A to G Substrate support structure 
         A 1 , B 1 , C 1 , D 1  Substrate support body 
         J Lighting fixture 
         H Light emitting device 
           1  Support plate 
           3  Enclosure member 
           3   a  Inner region 
           5  Bonding material 
           7  Element mounting substrate 
           9  Mounting portion 
           21  Light source portion 
           23  Casing 
           25  Light transmission portion