JP2016021545A - Mounting board mounted with light-emitting and wiring board for mounting light-emitting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting board capable of suppressing the effect of hue of a wiring line coming to the surface.SOLUTION: A mounting board comprises: a wiring board including a flexible resin board, mounting electrode parts provided on a first face of the resin board, and wiring lines provided on a second face of the resin board opposed to the first face and electrically connected with the mounting electrode parts; and a light-emitting part mounted on the mounting electrode parts. The mounting electrode parts are arranged so as to be covered by the light-emitting part seems when viewed along a normal direction of the resin board. The wiring board has a reflecting property such that it at least partly reflects light incident from the side of the first face. The resin board has through-holes formed therein, which extend through the resin board from the side of the first face to the side of the second face. The mounting electrode parts are electrically connected with the wiring lines through the through-holes. Further, the resin board has a white pigment or bubbles diffused therein.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a mounting board on which a light emitting component is mounted. The present invention also relates to a wiring board on which light emitting components are mounted.

  In recent years, it has been proposed to configure a light-emitting device such as a lighting fixture using a light-emitting component including a light-emitting element that functions as a point light source, such as a light-emitting diode. For example, in Patent Document 1, a flexible substrate on which terminals and wirings for driving a light-emitting component are formed is prepared, and the light-emitting component is mounted on the substrate to mount the light-emitting device. A substrate is configured.

  Incidentally, the directivity of light emitted from a light emitting element such as a light emitting diode is generally higher than the directivity of light emitted from a conventional fluorescent lamp. For this reason, for example, when using a light-emitting diode in a lighting fixture, in order to suppress the shape and arrangement of the light-emitting diode from being visually recognized by the user and to reduce straight light from the light-emitting diode, in general, as a light diffusing agent A functional lighting cover is provided to cover the light emitting diode. In addition, a reflective layer capable of reflecting light with high reflectivity is formed on the surface of the substrate on which the light emitting component is mounted in order to increase the light use efficiency. For example, Patent Document 1 proposes that a reflective layer including a metal thin film is formed on a portion of a surface of a substrate where a light emitting component electrode portion or wiring is not formed.

JP 2003-185813 A

  The metal material generally has a specific metallic luster and color. For example, copper, which is generally used as a material constituting wiring, reflects red light more strongly than blue light or green light, and thus the light reflected by copper contains redness. . Therefore, as in the above-mentioned Patent Document 1, when the reflective layer is formed on the surface of the substrate where the wiring for the light emitting component is not formed, that is, when the wiring is exposed on the surface of the mounting substrate It is conceivable that the light emitted from the luminaire will have a metal-specific color.

  The present invention has been made in consideration of such points, and an object thereof is to provide a mounting board and a wiring board that can suppress the influence of the color of the wiring.

  The present invention is a mounting board on which a light-emitting component is mounted, the resin board having flexibility, the mounting electrode portion provided on the first surface of the resin board, and the first of the resin board. A wiring board provided on a second surface facing the surface and electrically connected to the mounting electrode part, and a light emitting component mounted on the mounting electrode part, The mounting electrode portion is disposed so as to be covered by the light emitting component when viewed along the normal direction of the resin substrate, and the wiring substrate receives at least light incident from the first surface side. The resin substrate has a reflective property of partially reflecting, and the resin substrate has a through-hole penetrating from the first surface side to the second surface side, and the mounting electrode portion and the wiring are It is electrically connected through the through hole, and the resin substrate has a white pigment or the like. The air bubbles are dispersed, it is a mounting substrate.

  In the mounting board according to the present invention, the wiring board may further include a corrosion prevention layer provided on the second surface of the resin board so as to cover the wiring.

  The mounting substrate according to the present invention may further include a heat sink provided on the second surface side of the resin substrate. In this case, the heat radiating plate may contain aluminum nitride or aluminum oxide. Moreover, the said heat sink may be comprised by disperse | distributing a heat conductive filler in the resin material which has insulation. Further, an insulating resin material may be interposed between the second surface of the resin substrate and the heat dissipation plate, and a thermally conductive filler may be dispersed in the resin material. .

  In the mounting substrate according to the present invention, the resin substrate may include a polyester resin, an epoxy resin, or a polyimide resin, and the thickness of the resin substrate may be in a range of 10 μm to 300 μm.

  In the mounting substrate according to the present invention, the wiring substrate further includes a reflection auxiliary layer provided on the second surface side of the resin substrate, the reflection auxiliary layer includes an adhesive, and the mounting substrate includes: A heat sink attached to the wiring board via the reflection auxiliary layer may be further provided, and a plurality of recesses may be formed on a surface on the heat dissipation plate side of the surface of the reflection auxiliary layer.

  The present invention is a wiring board on which a light-emitting component is mounted, the resin board having flexibility, the mounting electrode portion provided on the first surface of the resin board, and the first of the resin board. A wiring provided on a second surface facing the surface and electrically connected to the mounting electrode portion, and a light emitting component mounted on the mounting electrode portion, and the resin substrate Is formed with a through hole penetrating from the first surface side to the second surface side, and the mounting electrode portion and the wiring are electrically connected through the through hole, It is a wiring substrate in which white pigments or bubbles are dispersed in the resin substrate.

  In the wiring board according to the present invention, the wiring board further includes a reflection auxiliary layer provided so as to be in contact with the second surface of the resin substrate, and the reflection auxiliary layer has a light reflectance in the reflection auxiliary layer. You may be comprised so that it may become higher than the reflectance of the light in the said resin substrate.

  In the wiring board according to the present invention, the wiring board further includes a reflection auxiliary layer provided so as to be in contact with the second surface of the resin substrate, and a refractive index of the reflection auxiliary layer is a resin included in the resin substrate. It may be smaller than the refractive index of the material.

  In the wiring board according to the present invention, the wiring board further includes a reflection auxiliary layer provided on the second surface side of the resin substrate, and the reflection auxiliary layer is partially formed by the second surface of the resin substrate. The exposed region may be in contact with the gas.

  According to the mounting substrate and the wiring substrate of the present invention, it is possible to suppress the influence of the color of the wiring from appearing.

FIG. 1 is a plan view showing a mounting board according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the mounting substrate of FIG. 1 as viewed from the II-II direction. FIG. 3 is a cross-sectional view showing a light emitting component mounted on a mounting board. FIG. 4 is a diagram illustrating a method for manufacturing a mounting board. FIG. 5 is a diagram illustrating a process of preparing a resin substrate in which a through hole is formed in the mounting substrate manufacturing method according to the embodiment of the present invention. FIG. 6 is a view showing a process of forming a back side wiring and a through wiring on a resin substrate in which a through hole is formed in the mounting board manufacturing method according to the embodiment of the present invention. FIG. 7 is a cross-sectional view showing a lighting device including a mounting board and a diffusion plate according to the present embodiment. FIG. 8 is a cross-sectional view illustrating a lighting device including a mounting substrate and a diffusion plate according to a first comparative embodiment. FIG. 9 is a cross-sectional view illustrating a lighting device including a mounting substrate and a diffusion plate according to a second comparative embodiment. FIG. 10 is a cross-sectional view showing a first modification of the mounting board according to the embodiment of the present invention. FIG. 11 is a sectional view showing a second modification of the mounting board according to the embodiment of the present invention. 12 is a view showing a state in which return light is reflected by the mounting board shown in FIG. FIG. 13 is a sectional view showing a third modification of the mounting board according to the embodiment of the present invention. FIG. 14 is a diagram illustrating a state in which return light is reflected by the mounting substrate illustrated in FIG. 13. FIG. 15 is a sectional view showing a fourth modification of the mounting board according to the embodiment of the present invention. FIG. 16 is a diagram illustrating a state in which return light is reflected by the mounting substrate illustrated in FIG. 15. FIG. 17 is a diagram illustrating an example in which the gap between the resin substrate and the auxiliary reflection layer is constituted by a recess formed on the surface of the auxiliary reflection layer on the resin substrate side. FIG. 18 is a diagram illustrating a state in which return light is reflected by a mounting board according to a fifth modification.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. First, an outline of the mounting substrate 40 according to the present embodiment will be described with reference to FIGS. As will be described later, the mounting substrate 40 can be combined with an illumination cover configured as a diffusion plate to constitute an illumination device.

As shown in FIG. 1, the mounting board 40 includes a wiring board 20 that is flexible and functions as a so-called flexible board, and a plurality of light emitting components 41 mounted on the wiring board 20. Yes. As long as a light emitting element that can function as a point light source is provided, the configuration of the light emitting component 41 is not particularly limited. For example, a light-emitting diode can be used as the light-emitting element, and a surface-mounted component including a light-emitting diode housed in a surface-mounted package can be used as the light-emitting component 41.

  As shown in FIG. 1, the wiring board 20 may include an extraction electrode portion 26 that is electrically connected to the light emitting component 41 via wirings 23 and 24 described later. The extraction electrode portion 26 may be preferably formed on the surface of the wiring board 20 opposite to the surface on which the light emitting component 41 is mounted, similarly to the backside wiring 23 described later.

  Next, the wiring board 20 will be described in detail with reference to FIG. The wiring substrate 20 includes a flexible resin substrate 21, a mounting electrode portion 22 provided on the first surface 21 a of the resin substrate 21, and a second surface 21 b facing the first surface 21 a of the resin substrate 21. And a wiring 23 electrically connected to the mounting electrode portion 22. The mounting electrode portion 22 is a portion for mounting the light emitting component 41 and is also referred to as a pad or a land. In the following description, the wiring 23 provided on the second surface 21 b of the resin substrate 21 is also referred to as a back-side wiring 23. As shown in FIG. 2, the wiring board 20 may further include a corrosion prevention layer 25 provided on the second surface 21 b of the resin substrate 21 so as to cover the back-side wiring 23. For example, the corrosion prevention layer 25 is provided over the entire area on the second surface 21 b of the resin substrate 21.

  As shown in FIG. 2, the resin substrate 21 is formed with a through hole 21c penetrating from the first surface 21a to the second surface 21b. A through-wiring 24 extending along the through-hole 21c is provided between the mounting electrode portion 22 and the back-side wiring 23 on the wall surface of the through-hole 21c. With this through wiring 24, the mounting electrode portion 22 and the back wiring 23 can be electrically connected. The dimensions and number of the through holes 21c are not particularly limited, and are appropriately determined according to the dimensions of the mounting electrode portion 22 and the like.

  2 shows an example in which the through wiring 24 is thinly formed on the wall surface of the through hole 21c, that is, an example in which the through wiring 24 is formed in a hollow shape. However, the present invention is not limited thereto. There is nothing. Although not shown, the through wiring 24 may be formed so as to fill the through hole 21c. As a result, the conductivity and thermal conductivity of the through wiring 24 can be further increased.

  In the present embodiment, “flexibility” refers to the degree that a fold does not occur in the wiring board 20 when the wiring board 20 is wound into a roll shape having a diameter of 30 cm in an environment of room temperature, for example, 25 ° C. Means flexibility. A “fold” is a deformation that appears in the wiring board 20 in a direction that intersects the direction in which the wiring board 20 is wound, and even if the wiring board 20 is wound in the reverse direction so that the deformation is restored. Means deformation that does not return. In addition, as long as the wiring board 20 has flexibility as a whole, the degree of flexibility in each of the resin substrate 21, the mounting electrode portion 22, the backside wiring 23, and the through wiring 24 is not particularly limited.

(Resin substrate)
The resin substrate 21 is a flexible substrate made of an insulating resin material. The material constituting the resin substrate 21 and the thickness of the resin substrate 21 are appropriately determined according to characteristics such as flexibility and strength required for the wiring substrate 20. For example, the resin substrate 21 may include a polyester resin, an epoxy resin, or a polyimide resin. Moreover, the thickness of the resin substrate 21 is set within a range of 10 μm to 300 μm, for example.

(Mounting electrode, backside wiring, through wiring, and extraction electrode)
As a material constituting the mounting electrode part 22, the back side wiring 23, the through wiring 24 and the extraction electrode part 26, a conductive material is used, for example, a metal material such as copper or silver. The materials constituting the mounting electrode part 22, the back side wiring 23, the through wiring 24, and the extraction electrode part 26 may be the same or different. For example, the mounting electrode part 22, the back wiring 23, the through wiring 24, and the extraction electrode part 26 may be formed simultaneously and continuously by patterning the same material. As long as the mounting substrate 40 is flexible in a desired direction, dimensions such as the thickness and width of the mounting electrode portion 22, the backside wiring 23, the through wiring 24, and the extraction electrode portion 26 are not particularly limited.

(Corrosion prevention layer)
The corrosion prevention layer 25 is a layer that is arbitrarily provided to prevent the backside wiring 23 from being corroded and rusted. The corrosion prevention layer 25 may contain a corrosion inhibitor such as triazole, imidazole, or chelating agent. The corrosion prevention layer 25 may be configured as a resin layer that seals the back-side wiring 23 from the external environment.

(Middle layer)
In FIG. 2, reference numeral 42 denotes between the light emitting component 41 and the mounting electrode portion 22 in order to couple the light emitting component 41 to the mounting electrode portion 22 and electrically connect the light emitting component 41 to the mounting electrode portion 22. Represents an intermediate layer interposed between the two. Examples of the material constituting the intermediate layer 42 include cream solder applied on the mounting electrode portion 22 in a reflow process described later. Cream solder includes a binder material such as flux, and metal powder that is dispersed in the binder material and melts during the reflow process. The composition of the metal powder contained in the cream solder is appropriately determined according to the temperature of the reflow process, the resistance of the wiring board 20 to the temperature, and the like. Although FIG. 2 shows an example in which the intermediate layer 42 is clearly interposed between the light emitting component 41 and the mounting electrode portion 22, the present invention is not limited to this. The shape and arrangement of the intermediate layer 42 are not particularly limited as long as the light emitting component 41 can be coupled to the mounting electrode portion 22 to electrically connect the light emitting component 41 to the mounting electrode portion 22.

(Optical characteristics of the wiring board)
Next, the optical characteristics of the wiring board 20 will be described. In the present embodiment, the wiring board 20 is configured to have a reflection characteristic that at least partially reflects light incident from the first surface 21 a side of the resin substrate 21. For example, white pigments and bubbles are dispersed inside the resin substrate 21. As a result, the light incident on the resin substrate 21 can be diffused in various directions, whereby the reflection characteristics in the wiring substrate 20 are realized. As the white pigment, white ceramic materials such as titanium oxide, calcium oxide, and zinc oxide can be used. In addition, various materials that can exhibit a white color, such as a white dye, can be used as the white pigment. A method for manufacturing the resin substrate 21 having such a reflection characteristic is not particularly limited, and a known method can be appropriately used. For example, pellets that are the raw materials for resin materials and white pigment are mixed and melted, and these mixed materials are molded by extrusion or the like, and fired as necessary to provide flexibility and reflection characteristics. Resin substrate 21 can be obtained.

  As described above, the thickness of the resin substrate 21 when the reflection characteristic is imparted to the resin substrate 21 itself is determined so as to ensure appropriate flexibility and reflection characteristics as the entire wiring board 20. For example, the thickness of the resin substrate 21 is in the range of 10 μm to 300 μm. Preferably, the resin substrate 21 is configured such that the total light reflectance in the light wavelength range of 380 nm to 780 nm is in the range of 60% to 99%. Here, the “total light reflectance” is the sum of regular reflectance and diffuse reflectance. The total light reflectance can be obtained in accordance with the total light reflectance measurement method of JIS K7375. Specifically, the total light reflectivity is the reflectivity when light is incident on the resin substrate 21 at an angle from the first surface 21a side of the resin substrate 21, and the spectrophotometer and the integrating sphere test stand. Can be obtained by calculating at an optical wavelength of 380 nm to 780 nm at 10 nm intervals and calculating an average value thereof. The total light reflectance is obtained as a relative value with the reflectance of a standard white plate containing barium sulfate as 100%.

  The resin substrate 21 may be further dispersed with a heat conductive filler having high heat conductivity. As a result, heat generated in the light emitting component 41 and conducted to the resin substrate 21 during operation of the mounting substrate 40 or in the reflow process can be radiated with high efficiency in the resin substrate 21. Thereby, the temperature rise of the light emitting component 41 can be suppressed, and therefore the reliability of the light emitting component 41 can be improved. As the thermally conductive filler, oxide particles such as alumina particles and silica particles, metal powder, and the like can be used. Moreover, since it can suppress that the temperature of the resin substrate 21 becomes high by improving the thermal radiation characteristic of the resin substrate 21, it can suppress that the resin substrate 21 deform | transforms with a heat | fever. .

(Light-emitting parts)
Next, the light emitting component 41 will be described with reference to FIG. As shown in FIG. 3, the light emitting component 41 is electrically connected to the case 45, the light emitting element 46 disposed in the case 45, the light emitting element 46, and at least partially exposed to the outside of the case 45. And a terminal 47. The terminal 47 may be directly connected to the light emitting element 46 or may be connected via a bonding wire 47a. The terminal 47 is generally made of a metal material such as copper or silver.

  Further, as shown in FIG. 3, a sealing material 48 may be provided around the light emitting element 46. The sealing material 48 may be configured to have a function of converting the wavelength of light emitted from the light emitting element 46. For example, when the light emitting element 46 includes a light emitting diode configured to emit blue light, the sealing material 48 may include a fluorescent agent that converts blue light into yellow light. As a result, blue light and yellow light can be mixed to produce white light. As shown in FIG. 3, a reflective material 49 that reflects light may be disposed around the sealing material 48. Thereby, the light emitted from the light emitting element 46 can be extracted from the case 45 with high efficiency.

  Preferably, the terminal 47 is disposed on the bottom surface 41b of the case 45 so that it is not visually recognized when viewed from the top surface 41a side of the case 45. That is, the terminal 47 is provided so as not to be exposed laterally from the bottom surface 41b. In this case, the mounting electrode portion 22 on the resin substrate 21 to which the terminal 47 is connected is also, like the terminal 47, so that it is not visible at all or almost when viewed from the top surface 41 a side of the case 45. The first surface 21a is preferably disposed on the first surface 21a. That is, it is preferable that the mounting electrode portion 22 is arranged so that the mounting electrode portion 22 is covered by the case 45 of the light emitting component 41 when viewed along the normal direction of the resin substrate 21. In this case, mounting the light emitting component 41 on the wiring board 20 causes the mounting electrode part 22 to be completely or almost hidden. The bottom surface 41b of the case 45 is a surface of the surface of the case 45 that faces the first surface 21a of the resin substrate 21, and the top surface 41a of the case 45 is a surface that faces the bottom surface 41b. .

  Next, an example of the manufacturing apparatus 10 for manufacturing the mounting substrate 40 will be described with reference to FIG.

(manufacturing device)
In FIG. 4, reference numeral 11 represents the unwinding portion 11 that holds the long wiring substrate 20 in a rolled state and unwinds the wiring substrate 20. Reference numeral 19 denotes a winding unit 19 that winds up the wiring board 20 on which the light emitting component 41 is mounted.

  In the manufacturing apparatus 10, an application part 13 for applying cream solder for forming the intermediate layer 42 and the intermediate layer 42 are provided on the mounting electrode part 22 of the wiring substrate 20 unwound from the unwinding part 11. The mounting unit 14 for mounting the light emitting component 41 on the mounting electrode unit 22 and the processing unit 16 for coupling the light emitting component 41 to the mounting electrode unit 22 via the intermediate layer 42 are provided. . The processing unit 16 is for coupling the light emitting component 41 to the mounting electrode unit 22 by heating the wiring board 20. In order to stabilize the temperature atmosphere around the processing unit 16, a chamber 17 surrounding the wiring substrate 20 around the processing unit 16 may be provided as shown in FIG.

(Manufacturing method of mounting substrate)
Next, an example of a method for manufacturing the mounting substrate 40 will be described.

  First, a long resin substrate 21 is prepared. In the present embodiment, as the resin substrate 21, a substrate configured to have a reflection characteristic of reflecting light incident from the first surface 21a side at least partially is prepared. For example, as described above, a resin substrate 21 in which white pigments, bubbles, and the like are dispersed is prepared.

  Next, as shown in FIG. 5, a through hole 21 c is formed at a position corresponding to a region where the mounting electrode portion 22 is formed in the resin substrate 21. As a method of forming the through hole 21c, various known methods such as a processing method using a laser beam or a punching processing method can be employed.

  Thereafter, as shown in FIG. 6, the above-described mounting electrode portion 22, backside wiring 23, and through wiring 24 are formed on the resin substrate 21. A method for forming conductive pads and wirings such as the mounting electrode portion 22, the backside wiring 23, and the through wiring 24 is not particularly limited, and various known methods can be used. For example, a paste containing fine particles of metal such as copper or silver may be printed in a pattern corresponding to the mounting electrode portion 22, the back side wiring 23, and the through wiring 24. The mounting electrode portion 22 can also be obtained by appropriately etching a metal film formed on the first surface 21a, the second surface 21b, or the wall surface of the through hole 21c of the resin substrate 21 by adhesion, vapor deposition, or plating. The back side wiring 23 and the through wiring 24 can be formed. In this way, the wiring substrate 20 including the resin substrate 21, the mounting electrode portion 22, the backside wiring 23, and the through wiring 24 provided on the resin substrate 21 can be obtained. Note that the extraction electrode portion 26 may be formed simultaneously with the mounting electrode portion 22, the back-side wiring 23, and the through wiring 24.

  Next, as shown in FIG. 4, the wiring substrate 20 is transported from the unwinding portion 11 toward the winding portion 19 by pulling the wiring substrate 20 wound around the unwinding portion 11 with a predetermined tension. The tension applied to the wiring board 20 is appropriately set so that the accuracy of the mounting position of the light emitting component 41 does not decrease due to the slack generated in the wiring board 20.

  Next, as shown in FIG. 4, a coating process for coating cream solder for forming the intermediate layer 42 on the mounting electrode unit 22 is performed using the coating unit 13. As the application unit 13, for example, a screen printer that applies cream solder using a metal mask having an opening formed at a position corresponding to the mounting electrode unit 22 can be used. After that, as shown in FIG. 4, using the mounting part 14, a mounting process of mounting the light emitting component 41 on the mounting electrode part 22 provided with the intermediate layer 42 is performed.

  Next, a processing step of heating the wiring board 20 with tension applied to the wiring board 20 is performed. In the processing step, the metal powder contained in the cream solder of the intermediate layer 42 is melted, whereby the light emitting component 41 is coupled to the mounting electrode portion 22. The heating temperature and the heating time during the treatment process are appropriately determined according to conditions recommended by the manufacturer of the light emitting component 41. For example, in the treatment step, first, heating is performed for about 2 minutes at a temperature of less than two hundred degrees, and then heating is performed for about one minute at a temperature of two hundred and several tens of degrees. In this way, a mounting board 40 including the wiring board 20 and the light emitting component 41 mounted on the wiring board 20 can be obtained.

(Lighting device)
Next, the lighting device 55 in which the mounting substrate 40 is incorporated will be described. As shown in FIG. 7, the lighting device 55 includes a mounting board 40 and a diffusion plate 50 arranged at a predetermined interval on the side of the mounting board 40 where the light emitting component 41 is mounted. . The diffusion plate 50 is a member configured to function as a light diffusing agent. As shown in FIG. 7, the mounting substrate 40 may further include a heat radiating plate 52 provided on the second surface 21 b side of the resin substrate 21. The heat radiating plate 52 efficiently mounts heat generated by, for example, the light emitting component 41 on the first surface 21a side of the resin substrate 21 and conducted from the first surface 21a side to the second surface 21b side. It is a member for discharging to the outside of the substrate 40. As the heat radiating plate 52, a heat sink having a large number of heat radiating fins can be used.

  Between the second surface 21 b of the resin substrate 21 and the heat radiating plate 52, a resin material for bringing the heat radiating plate 52 into close contact with the second surface 21 b of the resin substrate 21 may be interposed. The resin material interposed between the second surface 21b of the resin substrate 21 and the heat radiating plate 52 may be insulative or conductive as will be described later. Further, when the resin material interposed between the second surface 21b of the resin substrate 21 and the heat radiating plate 52 has an insulating property, in order to improve the thermal conductivity, aluminum nitride, oxidation oxide is included in the resin material. A thermally conductive filler containing a material having high thermal conductivity such as aluminum, boron nitride, or zinc oxide may be dispersed. The layer of the resin material interposed between the second surface 21b of the resin substrate 21 and the heat dissipation plate 52 may function also as the above-described corrosion prevention layer 25.

  When the back side wiring 23 and the heat sink 52 are in direct contact, or when the member interposed between the back side wiring 23 and the heat sink 52 has conductivity, the heat sink 52 has electrical insulation. Configured to have. In this case, preferably, the heat sink 52 is configured to have high thermal conductivity in addition to electrical insulation. For example, the heat radiating plate 52 can be formed using a material having a material having electrical insulation and high thermal conductivity, such as aluminum nitride and aluminum oxide. In addition, a thermally conductive filler containing a material having high thermal conductivity such as aluminum nitride, aluminum oxide, boron nitride, and zinc oxide in an insulating resin material such as silicone resin, acrylic resin, epoxy resin, polyimide resin, etc. The heat radiating plate 52 may be configured by dispersing.

  Hereinafter, the operation and effect of the mounting substrate 40 and the lighting device 55 according to the present embodiment having such a configuration will be described.

  In the present embodiment, a part of the light emitted from the light emitting component 41 passes through the diffusion plate 50 and reaches the user side, and the other is reflected by the diffusion plate 50 and returns to the mounting substrate 40. For example, as shown in FIG. 7, among the light emitted from the light emitting component 41, the light L <b> 1 incident on the diffusion plate 50 substantially along the normal direction of the diffusion plate 50 passes through the diffusion plate 50 and is on the user side. To. On the other hand, of the light emitted from the light emitting component 41, the light L2 incident on the diffusion plate 50 along the direction inclined from the normal direction of the diffusion plate 50 is reflected by the diffusion plate 50 and returned to the mounting substrate 40. Thereafter, the light is reflected by the resin substrate 21 and travels again toward the diffusion plate 50 and then passes through the diffusion plate 50 to reach the user side. As described above, according to the present embodiment, it is possible to use the light emitted from the light emitting component 41 along the direction inclined from the normal line direction of the diffusion plate 50, so that the light use efficiency can be improved. Moreover, it can suppress that the shape and arrangement | positioning of the light emitting component 41 are visually recognized by the user.

  Further, according to the present embodiment, as described above, the back-side wiring 23 electrically connected to the mounting electrode portion 22 is on the side opposite to the first surface 21a of the resin substrate 21 on which the light-emitting component 41 is provided. , Provided on the second surface 21 b of the resin substrate 21. The resin substrate 21 is formed with a through hole 21c penetrating from the first surface 21a side to the second surface 21b side. The mounting electrode portion 22 and the backside wiring 23 are electrically connected through the through hole 21c. It is connected to the. As described above, according to the present embodiment, the wiring connected to the mounting electrode portion 22 is provided on the second surface 21b side of the resin substrate 21 as the back-side wiring 23, thereby being reflected by the diffusion plate 50 and mounted on the mounting substrate. It can suppress that the light L2 which returned to 40 is reflected by wiring. Thereby, it is possible to suppress the influence of the color of the wiring from appearing on the light emitted from the lighting device 55. For example, when the wiring connected to the mounting electrode unit 22 is made of copper, it is possible to suppress the reddish light caused by the copper from being emitted from the lighting device 55.

  By the way, in this Embodiment, in order to make the resin substrate 21 have flexibility, the thickness of the resin substrate 21 is small. This means that light easily passes through the resin substrate 21. When the light passes through the resin substrate 21, even if the wiring is provided on the second surface 21b of the resin substrate 21 as described above, the light transmitted through the resin substrate 21 reaches the second surface 21b side, As a result, the color of the wiring may appear. Here, in the present embodiment, as described above, the wiring board 20 is configured to have reflection characteristics. For this reason, even if the resin substrate 21 has flexibility and the thickness of the resin substrate 21 is small, light incident from the first surface 21a side of the resin substrate 21 reaches the second surface 21b. Can be suppressed. Therefore, according to the present embodiment, it is possible to simultaneously realize that the wiring board 20 is flexible and that the influence of the color of the wiring appears.

  In the present embodiment, preferably, as described above, the mounting electrode 22 is covered with the light emitting component 41 so that the mounting electrode portion 22 of the wiring substrate 20 is covered with the light emitting component 41 when viewed along the normal direction of the resin substrate 21. The part 22 is arranged. That is, the mounting electrode portion 22 is disposed so as to be hidden by the light emitting component 41. In this case, the light L <b> 2 reflected by the diffusion plate 50 and returning to the mounting substrate 40 is not reflected by the mounting electrode unit 22. For this reason, it can suppress that the influence of the color of the mounting electrode part 22 appears in the light radiate | emitted from the illuminating device 55. FIG.

Further, according to the present embodiment, on the first surface 21 a side of the resin substrate 21, for example, the heat generated in the light emitting component 41 is transmitted to the first side of the resin substrate 21 using the through hole 21 c, the through wiring 24 and the back side wiring 23. It can be transmitted to the second surface 21b side with high thermal conductivity. Further, since the second surface 21b side of the resin substrate 21 is the side opposite to the side where the user is located, various members can be provided on the second surface 21b side with a high degree of freedom.
For example, as described above, the heat radiating plate 52 can be provided on the second surface 21b side of the resin substrate 21, whereby heat generated in the light emitting component 41 can be released to the outside with high efficiency. Thus, the heat radiation design of the mounting substrate 40 can be easily realized with high efficiency. Accordingly, it is possible to suppress the light emitting component 41 and the resin substrate 21 from becoming high temperature when the mounting substrate 40 is used. Thereby, the reliability of the light emitting component 41 can be improved, and the resin substrate 21 can be prevented from being deformed by heat.
Moreover, it becomes easy to provide a member for protecting the back wiring 23 on the second surface 21b side of the resin substrate 21. For example, a corrosion inhibitor that covers the backside wiring 23 can be provided on the second surface 21 b side of the resin substrate 21 in order to suppress corrosion of the backside wiring 23. As a result, it is possible to suppress the backside wiring 23 from being oxidized or to cause migration between adjacent backside wirings 23, thereby improving the reliability of the backside wiring 23. .

  Further, according to the present embodiment, since the back wiring 23 is provided on the second surface 21b side of the resin substrate 21, the extraction electrode part 26 can be provided on the second surface 21b side. Therefore, it becomes easy to arrange a cable and a connector for supplying power and a control signal to the light emitting component 41 via the extraction electrode portion 26 on the second surface 21b side. That is, the mounting board 40 can be easily connected to the external power supply or the external control circuit.

  Further, according to the present embodiment, since the back side wiring 23 is provided on the second surface 21b side of the resin substrate 21, the corrosion prevention layer 25 for suppressing the back side wiring 23 from rust is also provided on the second surface of the resin substrate 21. 21b. As described above, since the second surface 21b side of the resin substrate 21 is the side opposite to the side where the user is positioned, the layers and members provided compared to the first surface 21a of the resin substrate 21 are provided. There are few restrictions on the shape and pattern. For example, the corrosion prevention layer 25 can be provided over the entire area on the second surface 21 b of the resin substrate 21. Therefore, the process of patterning the corrosion prevention layer 25 into a predetermined pattern is unnecessary, and therefore, the effect of suppressing rusting of the back side wiring 23 can be realized with a small number of man-hours.

(First comparison form)
Next, the effect of the present embodiment will be described in comparison with the first comparative embodiment. FIG. 8 is a longitudinal sectional view showing a lighting device including the mounting substrate 100 and the diffusion plate 50 according to the first comparative embodiment.

  In the mounting substrate 100 according to the first comparative form shown in FIG. 8, the wiring 101 connected to the mounting electrode portion 22 is provided on the first surface 21 a side of the resin substrate 21. Other configurations are the same as those of the present embodiment shown in FIGS. In the first comparative form shown in FIG. 8, the same parts as those of the present embodiment shown in FIGS.

  In the first comparative embodiment, as shown in FIG. 8, the light L2 incident on the diffusion plate 50 along the direction inclined from the normal direction of the diffusion plate 50 out of the light emitted from the light emitting component 41. A part of the light is reflected by the diffusion plate 50 and returned to the mounting substrate 40, and then is reflected by the wiring 101 provided on the first surface 21 a of the resin substrate 21 and heads toward the diffusion plate 50 again. Through to the user side. For this reason, light with a tint attributed to the metal material constituting the wiring 101 is emitted from the lighting device, for example, a reddish light attributed to copper.

  On the other hand, according to the present embodiment, by providing the wiring connected to the mounting electrode portion 22 as the back-side wiring 23 on the second surface 21b side of the resin substrate 21, light emitted from the lighting device 55 is emitted. In addition, the influence of the color of the wiring can be suppressed.

  In the first comparative embodiment, since the wiring 101 is provided on the first surface 21a side of the resin substrate 21, although not shown, a corrosion prevention layer for suppressing the wiring 101 from rust is also provided on the resin substrate 21. It will be provided on the first surface 21a side. On the other hand, a mounting electrode portion 22 is also provided on the first surface 21 a side of the resin substrate 21. For this reason, if a corrosion prevention layer is provided over the entire area of the first surface 21a of the resin substrate 21, the contact resistance between the mounting electrode portion 22 and the light emitting component 41 increases. Therefore, when the corrosion prevention layer is provided on the first surface 21a side of the resin substrate 21, a step of patterning the corrosion prevention layer into a predetermined pattern is required.

  On the other hand, according to the present embodiment, since the corrosion prevention layer 25 is provided on the second surface 21b side of the resin substrate 21, there is no need to pattern the corrosion prevention layer 25 into a predetermined pattern. The effect of suppressing the rust of the backside wiring 23 can be realized with a small number of man-hours.

(Second comparison form)
Next, the effect of the present embodiment will be described in comparison with the second comparative embodiment. FIG. 9 is a longitudinal sectional view showing a lighting device including a mounting substrate 110 and a diffusion plate 50 according to a second comparative embodiment.

  Also in the mounting substrate 110 according to the second comparative form shown in FIG. 9, the wiring 101 is provided on the first surface 21a side of the resin substrate 21 as in the case of the first comparative form shown in FIG. ing. In the second comparative embodiment, the reflection characteristic on the mounting substrate 110 is realized by the reflection layer 111 provided on the first surface 21 a of the resin substrate 21. The reflective layer 111 can be formed of a white ceramic material that can achieve high reflectivity, such as titanium oxide, calcium oxide, and zinc oxide, as described in, for example, Japanese Patent Application Laid-Open No. 2006-147999. Other configurations are the same as those of the present embodiment shown in FIGS. In the second comparative embodiment shown in FIG. 9, the same parts as those of the present embodiment shown in FIGS.

  In the second comparative embodiment, as shown in FIG. 9, by forming the reflective layer 111 so as to cover the wiring 101, the influence of the color of the wiring 101 appears on the light emitted from the lighting device. Can be suppressed.

  On the other hand, in the step of forming the reflective layer 111 containing a white ceramic material, first, an application step of applying a paste containing a ceramic material powder onto the first surface 21a of the resin substrate 21 is performed, and then the resin A baking process is performed in which the substrate 21 is heated to bake and harden the paste. In this case, it is conceivable that the resin substrate 21 may be damaged by being exposed to a high temperature for a long time, for example, 30 minutes or 1 hour in the baking step. For example, when the firing temperature is higher than the glass transition temperature of the resin material constituting the resin substrate 21, the resin substrate 21 may be deformed. Further, when the coefficient of thermal expansion of the material constituting the reflective layer 111 and the coefficient of thermal expansion of the material constituting the resin substrate 21 are greatly different, the resin substrate 21 is caused by curing shrinkage of the material constituting the reflective layer 111. It is conceivable that a large stress is generated in the resin substrate 21 and the resin substrate 21 is deformed. Further, when the resin substrate 21 is deformed, the reflective layer 111 may be peeled off from the resin substrate 21 or a crack may be formed in the reflective layer 111.

  On the other hand, according to the present embodiment, the reflection characteristic of the mounting substrate 40 is realized by dispersing a white pigment, bubbles, or the like on the resin substrate 21. For example, pellets used as a raw material for a resin material and a white pigment are mixed and melted, these mixed materials are molded by extrusion molding or the like, and fired as necessary to provide flexibility and reflection characteristics. A resin substrate 21 is prepared. Therefore, according to the present embodiment, the chance that the molded resin substrate 21 is exposed to a high temperature can be reduced as compared with the case of the second comparative embodiment. For this reason, it is possible to obtain the mounting substrate 40 having the reflection characteristics while suppressing the resin substrate 21 from being damaged. For example, the resin substrate 21 can be prevented from being deformed by heat.

  Note that various modifications can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(First modification)
In the above-described embodiment, an example in which the reflection characteristic of the wiring substrate 20 is realized by dispersing white pigment, bubbles, or the like inside the resin substrate 21 has been described. However, the specific configuration of the wiring board 20 is not particularly limited as long as the wiring board 20 can reflect light. For example, as shown in FIG. 10, the reflection characteristic of the wiring substrate 20 may be realized by forming a reflection layer 28 on the first surface 21 a of the resin substrate 21.

  As a method of forming the reflective layer 28, first, a paste containing a reflective material such as a white ceramic material or metal powder is provided on the first surface 21a of the resin substrate 21, and then a baking step is performed in which the paste is baked and hardened. The method of carrying out can be considered. Although not shown, the paste described above is provided on a predetermined base material, a firing process is performed to form the reflective layer 28 on the base material, and then a laminate including the base material and the reflective layer 28 is formed. A method of attaching to the first surface 21a of the resin substrate 21 via an adhesive layer or the like is also conceivable. In the latter method, the baking step for baking and solidifying the reflective layer 28 is performed independently of the resin substrate 21 without affecting the resin substrate 21. For this reason, it is possible to obtain the wiring substrate 20 having the reflection characteristics while suppressing the resin substrate 21 from being damaged.

(Second modification)
In the above-described embodiment, an example in which the reflection characteristic of the wiring substrate 20 is realized by dispersing white pigment, bubbles, or the like inside the resin substrate 21 has been described. By the way, the reflectance of light in the resin substrate 21 increases as the thickness of the resin substrate 21 increases and as the amount and volume of white pigment and bubbles added and dispersed in the resin substrate 21 increase. On the other hand, in order to ensure the flexibility of the resin substrate 21, the thickness of the resin substrate 21 and the amount of white pigment or bubbles added are limited. Moreover, the heat dissipation of the resin substrate 21 will fall, so that the thickness of the resin substrate 21 is large. Furthermore, the greater the thickness of the resin substrate 21, the greater the expansion of the resin substrate 21 in the thickness direction that occurs when the resin substrate 21 is heated. As a result, the step of laminating other layers on the resin substrate 21, In the mounting process of mounting the light emitting component 41 on the wiring substrate 20 including the resin substrate 21, misalignment is likely to occur. On the other hand, if the thickness of the resin substrate 21 is too small, it becomes difficult to handle the resin substrate 21, and the resin substrate 21 is easily broken during the manufacturing process. Furthermore, unevenness due to heat shrinkage is likely to occur on the surface of the resin substrate 21. Considering these points, the thickness of the resin substrate 21 is preferably set in the range of 10 μm to 300 μm, more preferably in the range of 20 μm to 150 μm, as described above.
Thus, when the upper limit of the thickness of the resin substrate 21 is determined, it is not easy to bring the reflectance of the resin substrate 21 alone close to 100%.

  As described above, it is difficult for the resin substrate 21 alone to reflect the light returning to the mounting substrate 40 with a sufficiently high reflectance. Considering this point, in the present modification, as shown in FIGS. 11 and 12, the reflection auxiliary layer 29 is provided on the second surface 21 b side of the resin substrate 21 so as to be in contact with the second surface 21 b of the resin substrate 21. Propose to provide. The auxiliary reflection layer 29 is a layer configured such that the reflectance of light in the auxiliary reflection layer 29 is higher than the reflectance of light in the resin substrate 21. By providing such a reflection auxiliary layer 29, it is possible to sufficiently increase the reflectance of light in the wiring substrate 20 while suppressing an increase in the thickness of the wiring substrate 20. Accordingly, it is possible to provide the resin substrate 21 having flexibility and high light reflectance.

  Note that “the reflectance of light in the reflection auxiliary layer 29 is higher than the reflectance of light in the resin substrate 21” means that the resin substrate 21 and the reflection auxiliary layer 29 provided on a support having the same optical characteristics are used. In the case where the test pieces including each of the test pieces are prepared and the total light reflectance of each test piece is measured, the total light reflectance of the test piece including the reflection assisting layer 29 is greater than the total light of the test piece including the resin substrate 21. It means that it becomes higher than the reflectance. Further, “so as to be in contact with the second surface 21 b” means that no other layer such as an adhesive layer is interposed between the second surface 21 b of the resin substrate 21 and the auxiliary reflection layer 29. . By not interposing an adhesive layer or the like, it is possible to suppress the occurrence of irregular reflection of light before reaching the reflection auxiliary layer 29. Therefore, the light returned to the mounting substrate 40 can be used more effectively.

  As long as the reflectance higher than that of the resin substrate 21 can be realized and the flexibility of the wiring substrate 20 as a whole can be realized, the specific configuration of the auxiliary reflection layer 29 is particularly limited. Absent. For example, a metal material or a ceramic material can be used as the material constituting the auxiliary reflection layer 29. Examples of the metal material include copper, aluminum, silver, iron, and alloys thereof. Examples of the ceramic material include aluminum oxide and aluminum nitride.

  When the reflection auxiliary layer 29 includes a metal material, the reflection auxiliary layer 29 can be formed so as to be in direct contact with the second surface 21b of the resin substrate 21 by using a sputtering method, a vapor deposition method, or the like. When the auxiliary reflection layer 29 contains a ceramic material, first, a paste containing the ceramic material is applied onto the second surface 21b of the resin substrate 21, and then the paste is baked, whereby the second surface of the resin substrate 21 is obtained. The auxiliary reflection layer 29 can be formed so as to be in direct contact with 21b. In addition, when applying a paste on the 1st surface 21a of the resin substrate 21 and providing the conventional reflective layer, it is necessary to apply | coat a paste on a pattern so that it may not overlap with the electrode part 22 for mounting. On the other hand, in the present embodiment, a paste may be applied to the entire surface of the second surface 21b. Therefore, the coating process is facilitated as compared with the case of coating on the first surface 21a side.

  As described above, a metal material is used as the material constituting the back side wiring 23 provided on the second surface 21 b side of the resin substrate 21. Accordingly, when the auxiliary reflection layer 29 includes a metal material, the back wiring 23 and the auxiliary reflection layer 29 may be formed using the same metal material. For example, a metal material layer is first formed on the second surface 21b of the resin substrate 21 using a sputtering method, a vapor deposition method, a plating method, a printing method, or the like, and then a metal material layer is used using a photolithography method or the like. By patterning, the back side wiring 23 and the reflection auxiliary layer 29 can be simultaneously formed of the same material. In the case of using the plating method and the printing method, not only the procedure of forming the back side wiring 23 and the reflection assisting layer 29 by patterning this layer after providing the metal material layer as described above, but also the back side wiring 23 and the reflection method. A procedure of forming a layer of a metal material so as to have a pattern corresponding to the auxiliary layer 29 can be adopted. That is, the step of patterning the metal material layer can be eliminated. For this reason, it is preferable to use a plating method and a printing method from the viewpoint of reducing man-hours.

  As shown in FIG. 11, when a conductive material such as a metal material is used as the material constituting the reflection auxiliary layer 29, in order to prevent the back side wiring 23 and the reflection auxiliary layer 29 from conducting. In addition, the reflection auxiliary layer 29 is provided in a region where the back-side wiring 23 is not formed in the region on the second surface 21 b of the resin substrate 21. When a material that does not have conductivity is used as the material constituting the auxiliary reflection layer 29, although not shown, the back wiring 23 and the auxiliary reflection layer 29 may be in contact with each other or may partially overlap.

  The thickness of the auxiliary reflection layer 29 is set so that the flexibility of the wiring board 20 is maintained. When the auxiliary reflection layer 29 includes a metal material, the thickness of the auxiliary reflection layer 29 is, for example, in the range of 10 nm to 300 nm. When the auxiliary reflection layer 29 includes a ceramic material, the thickness of the auxiliary reflection layer 29 is, for example, in the range of 0.01 μm to 10 μm.

  Preferably, the auxiliary reflection layer 29 is configured such that the thermal conductivity of the auxiliary reflection layer 29 is higher than the thermal conductivity of the resin substrate 21. Thereby, the heat generated in the light emitting component 41 can be efficiently diffused in the surface direction of the wiring board 20, and thereby the temperature distribution of the wiring board 20 in the surface direction can be made uniform. Therefore, when the wiring board 20 and the mounting board 40 are attached to the heat sink 52 described later, heat can be efficiently transmitted to the heat sink 52. The “surface direction of the wiring board 20” is a direction orthogonal to the normal direction of the wiring board 20.

  As described above, increasing the thermal conductivity in the reflection auxiliary layer 29 is intended to mainly promote the diffusion of heat in the surface direction of the wiring board 20. Therefore, the thermal conductivity in the reflection auxiliary layer 29 does not need to be higher than the thermal conductivity in the resin substrate 21 in all directions, and the thermal conductivity in the reflection auxiliary layer 29 is at least in the surface direction of the wiring substrate 20. What is necessary is just to become higher than the heat conductivity in the board | substrate 21. FIG. For example, the thermal conductivity of the auxiliary reflection layer 29 in the surface direction is 100 W / (m · K) or more.

Preferably, the resin substrate 21 and the auxiliary reflection layer 29 are configured such that the difference between the thermal expansion coefficient of the resin substrate 21 and the thermal expansion coefficient of the reflection auxiliary layer 29 is ± 5 × 10 ⁻⁶ / ° C. or less. . As a result, during a process in which heat is applied to the wiring board 20 such as a reflow process to be described later, the auxiliary reflection layer 29 may be peeled off from the resin substrate 21 due to a difference in thermal expansion coefficient. It is possible to suppress the occurrence of deformation such as warpage.

  FIG. 12 is a diagram for explaining an example of the reflection of light that occurs when the mounting substrate 40 and the diffusion plate 50 according to the present modification are combined. As shown by an arrow L <b> 3 in FIG. 12, part of the light reflected by the diffusion plate 50 and returning to the mounting substrate 40 may pass through the resin substrate 21 without being reflected by the resin substrate 21. Even in this case, according to the present modification, such light can be reflected by the auxiliary reflection layer 29 and directed to the diffusion plate 50 again. As described above, according to the present modification, even when the reflectance of light on the resin substrate 21 is not sufficiently high, the light transmitted through the resin substrate 21 can be reflected by the reflection assisting layer 29. The light utilization efficiency in the device 55 can be sufficiently increased.

(Third Modification)
In the second modification described above, an example in which the auxiliary reflection layer 29 is configured to have a higher reflectance than the resin substrate 21 has been described. However, the configuration of the auxiliary reflection layer 29 for improving the reflection characteristics of the wiring board 20 is not limited to the configuration shown in the second modification. In the present modification, the reflection auxiliary layer 29 is formed using a material having a refractive index lower than that of the material forming the resin substrate 21, whereby the second surface 21 b of the resin substrate 21 and the reflection auxiliary layer are formed. An example in which light is reflected at the interface with 29 will be described. In the third modification shown in FIGS. 13 and 14, the same parts as those in the above-described embodiment and each modification are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, when it is clear that the effects obtained in the above-described embodiment and each modification can be obtained in the third modification, the description thereof may be omitted.

  In the present modification shown in FIG. 13, the auxiliary reflection layer 29 is a layer configured such that the refractive index thereof is smaller than the refractive index of the resin material constituting the resin substrate 21. For example, the auxiliary reflection layer 29 includes a resin material, and this resin material has a lower refractive index than the resin material included in the resin substrate 21. By providing such a reflection auxiliary layer 29, the light traveling from the first surface 21a side to the second surface 21b side of the resin substrate 21 is transmitted to the interface between the second surface 21b of the resin substrate 21 and the reflection auxiliary layer 29. And can be emitted again from the first surface 21a. For this reason, the reflectance of the light in the wiring board 20 can be made sufficiently high while suppressing an increase in the thickness of the wiring board 20. Accordingly, it is possible to provide the resin substrate 21 having flexibility and high light reflectance. In the present specification, the refractive index means the refractive index with respect to light having a wavelength of 500 nm unless otherwise specified. Further, “so as to be in contact with the second surface 21 b” means that no other layer is interposed between the second surface 21 b of the resin substrate 21 and the auxiliary reflection layer 29.

  Preferably, the resin material of the auxiliary reflection layer 29 is made of an adhesive having transparency. In this case, the reflection auxiliary layer 29 can function as an adhesive layer for attaching a heat radiating plate such as an aluminum plate to the wiring board 20. As the adhesive constituting the resin material of the auxiliary reflection layer 29, what is called an OCA (Optical Clear Adhesive) or an optical transparent adhesive such as an acrylic resin, an epoxy resin, a urethane resin, or a fluororesin can be used. . For example, when polyethylene terephthalate having a refractive index of approximately 1.6 is used as the resin material of the resin substrate 21, an acrylic resin having a refractive index of approximately 1.47 is used as the resin material of the reflection auxiliary layer 29. Can do. Note that “transparency” means that the total light transmittance of the resin material of the auxiliary reflection layer 29 is 70% or more. When the resin material of the auxiliary reflection layer 29 is composed of an adhesive having transparency, a release sheet for protecting the surface of the auxiliary reflection layer 29 is provided on the auxiliary reflection layer 29, although not shown. May be.

  The thickness of the auxiliary reflection layer 29 is set so that the flexibility of the wiring board 20 is maintained, and is within a range of 5 μm to 500 μm, for example.

  Although not shown, the reflection assisting layer 29 may be configured using a resin material and a filler dispersed in the resin material. As the resin material, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, an epoxy resin, or a polyimide resin can be used in the same manner as the resin material of the resin substrate 21. As the filler, a white ceramic material such as titanium oxide, calcium oxide, aluminum oxide, and zinc oxide can be used as in the case of the white pigment of the resin substrate 21. Further, since it is not particularly necessary that the reflection auxiliary layer 29 is white, it is also possible to use a material having a color other than white as the filler material. For example, aluminum, silver, zinc, copper, gold, iron, or the like can be used. Thus, the degree of freedom of the material constituting the auxiliary reflection layer 29 is higher than the degree of freedom of the material constituting the resin substrate 21. When the auxiliary reflection layer 29 includes a resin material and a filler dispersed in the resin material, a value obtained by multiplying the refractive index of the resin material by the weight ratio of the resin material in the auxiliary reflection layer 29 and the refractive index of the filler. The average value of the refractive index calculated as the sum of the values obtained by multiplying the weight ratio of the filler in the reflection auxiliary layer 29 is adopted as the refractive index of the reflection auxiliary layer 29.

  The method for forming the auxiliary reflection layer 29 on the second surface 21b of the resin substrate 21 is not particularly limited, and a known method such as a printing method is used. For example, a paste containing a resin material and, if necessary, a filler is prepared, and this paste is applied onto the second surface 21b of the resin substrate 21 so as to be in direct contact with the second surface 21b of the resin substrate 21. The reflection auxiliary layer 29 can be formed.

  As shown in FIG. 13, the reflection auxiliary layer 29 may be provided not only in a region that can directly contact the second surface 21 b of the resin substrate 21, but also in a region that overlaps the back-side wiring 23. Although not shown, the reflection auxiliary layer 29 may be provided only in a region that does not overlap the back-side wiring 23.

  FIG. 14 is a view for explaining an example of reflection of light generated when the mounting substrate 40 and the diffusion plate 50 according to this modification are combined. In this modified example, as indicated by an arrow L3 in FIG. 14, the light transmitted through the resin substrate 21 is reflected at the interface between the second surface 21b of the resin substrate 21 and the auxiliary reflection layer 29, and is again diffused. To 50.

  Further, according to the present embodiment, since the auxiliary reflection layer 29 includes an adhesive, the auxiliary reflection layer 29 can also function as an adhesive layer for attaching the heat sink 52 to the wiring board 20. For this reason, the wiring board 20 which has a high reflective characteristic and the attachment property to the heat sink 52 was improved can be comprised more simply. Moreover, the wiring board 20 can be attached to the heat sink 52 having various shapes such as a curved surface.

(Fourth modification)
Next, a fourth modification will be described with reference to FIGS. 15 and 16. In the fourth modified example, the auxiliary reflection layer 29 is configured such that the second surface 21b of the resin substrate 21 partially becomes an exposed region 21e in contact with the gas. In the fourth modification example shown in FIGS. 15 and 16, the same parts as those in the third modification example described above are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, when it is clear that the effects obtained in the third modification can be obtained in the fourth modification, the description thereof may be omitted.

  As shown in FIG. 15, the wiring substrate 20 includes a reflection auxiliary layer 29 provided on the second surface 21 b side of the resin substrate 21. The auxiliary reflection layer 29 is configured such that the second surface 21b of the resin substrate 21 partially becomes an exposed region 21e in contact with the gas. The resin material of the auxiliary reflection layer 29 contains an adhesive. For this reason, the reflection auxiliary layer 29 can function as an adhesive layer for attaching the heat sink 52 to the wiring board 20.

  The thickness of the auxiliary reflection layer 29 is such that when the heat sink 52 is attached to the second surface 21b side of the resin substrate 21 through the auxiliary reflection layer 29 as described later, the exposed region 21e of the resin substrate 21 and the heat sink 52 Is set such that a gap 29s where a gas such as air exists is formed. For example, the thickness of the auxiliary reflection layer 29 is set in the range of 5 μm to 500 μm.

  FIG. 16 is a cross-sectional view showing a state where the heat radiating plate 52 is attached to the mounting board 40 of FIG. As described above, the gap portion 29s in which a gas such as air exists is formed between the exposed region 21e of the resin substrate 21 and the heat radiating plate 52. Therefore, the refractive index of the gap portion 29s is approximately 1. It has become. That is, the refractive index of the gap portion 29s is significantly smaller than the refractive index of the resin substrate 21. Therefore, a part of the return light not reflected by the resin substrate 21 is reflected at the interface between the second surface 21b of the resin substrate 21 and the gap 29s after passing through the resin substrate 21 as indicated by an arrow L3. Then, the light travels again toward the diffusion plate 50 and passes through the diffusion plate 50 to reach the user side. For this reason, also in this modification, even if the reflectance of light on the resin substrate 21 is not sufficiently high, the light transmitted through the resin substrate 21 is formed between the resin substrate 21 and the heat dissipation plate 52. Since it can reflect using the space | gap part 29s, the utilization efficiency of the light in the illuminating device 55 can be made high enough.

  As indicated by an arrow L4 in FIG. 16, a part of the return light that is not reflected by the resin substrate 21 is not reflected at the interface between the resin substrate 21 and the gap portion 29s, and passes through the gap portion 29s. It may reach the surface of the heat sink 52. Even in this case, as described above, the gap portion 29s is a space filled with a gas such as air, and thus light passes through the gap portion 29s with high transmittance and reaches the surface of the heat dissipation plate 52. be able to. Accordingly, it is possible to reduce the amount of energy loss that occurs in the light when passing through the resin substrate 21 and reaching the surface of the heat sink 52.

  In the present modification, unlike the above-described third modification, it is not always necessary to cause light reflection at the interface between the second surface 21 b of the resin substrate 21 and the reflection auxiliary layer 29. Therefore, a material having a refractive index higher than that of the resin material of the resin substrate 21 may be used as the resin material of the auxiliary reflection layer 29. Of course, as the resin material of the auxiliary reflection layer 29, a material having a refractive index smaller than that of the resin material of the resin substrate 21 may be used.

  Of the light that is reflected by the diffusion plate 50 and returns to the mounting substrate 40, the light that reaches the back-side wiring 23 is reflected by the mounting electrode portion 22 and the back-side wiring 23 and travels toward the diffusion plate 50 again. Thus, high reflection characteristics are realized in the region on the second surface 21b of the resin substrate 21 where the back-side wiring 23 is provided. Therefore, preferably, the above-described gap portion 29s is configured to be in contact with the second surface 21b in a region of the second surface 21b of the resin substrate 21 where the back-side wiring 23 is not provided. In other words, the reflection auxiliary layer 29 is preferably provided in a region overlapping the back-side wiring 23 when viewed from the normal direction of the resin substrate 21. As a result, the area of the auxiliary reflection layer 29 is increased while forming more voids 29 s in the region of the second surface 21 b of the resin substrate 21 that does not overlap the back wiring 23 when viewed from the normal direction of the resin substrate 21. be able to. This makes it possible to achieve both the reflection characteristics of the wiring board 20 and the adhesion and mounting properties of the wiring board 20 to the heat sink 52.

  The method for forming the auxiliary reflection layer 29 is not particularly limited, and various known methods can be used. For example, the reflection auxiliary layer 29 may be formed by applying a paste containing an adhesive on the second surface 21b side of the resin substrate 21 in a pattern using a printing method such as a screen printing method or an ink jet method. . Further, first, the auxiliary reflection layer 29 that extends over the entire area on the second surface 21b side of the resin substrate 21 may be provided, and then the auxiliary reflection layer 29 may be patterned using a photolithography method.

  In FIGS. 15 and 16, the auxiliary reflection layer 29 is provided in a pattern on the second surface 21 b of the resin substrate 21, so that the wiring substrate 20 and the heat dissipation plate 52 bonded together via the auxiliary reflection layer 29 are provided. An example in which a gap 29s is formed between them is shown. However, the method of forming the gap 29s in contact with the second surface 21b of the resin substrate 21 using the auxiliary reflection layer 29 is not limited to the examples shown in FIGS. For example, as shown in FIG. 17, a method of forming a plurality of recesses 29e on the surface of the auxiliary reflection layer 29 on the surface of the resin substrate 21 is also conceivable. In this case, a region of the second surface 21b of the resin substrate 21 that overlaps the concave portion 29e of the auxiliary reflection layer 29 when viewed along the normal direction of the resin substrate 21 is an exposed region 21e that contacts the gas. That is, the concave portion 29 e of the auxiliary reflection layer 29 can constitute a gap portion 29 s that is in contact with the second surface 21 b of the resin substrate 21. Therefore, also in the mounting substrate 40 shown in FIG. 17, a part of the return light that is not reflected by the resin substrate 21 is between the second surface 21b of the resin substrate 21 and the gap 29s, as indicated by an arrow L3. It can be reflected at the interface.

  The dimension of the concave portion 29e of the auxiliary reflection layer 29 is such that the second surface 21b of the resin substrate 21 and the auxiliary reflection layer 29 are formed even when the auxiliary reflection layer 29 is deformed when the heat sink 52 is attached to the wiring board 20. The gap 29s is set so as to be formed therebetween. For example, the depth of the concave portion 29e of the auxiliary reflection layer 29 is set within a range of 3 μm to 450 μm. In addition, in the state before the resin substrate 21 and the heat sink 52 are bonded together, the reflection auxiliary layer 29 may be provided on the resin substrate 21 side, or may be provided on the heat sink 52 side.

(Fifth modification)
Next, a fifth modification will be described with reference to FIG. In the fifth modification shown in FIG. 18, the same parts as those in the third modification or the fourth modification described above are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, when it is clear that the effects obtained in the third modification or the fourth modification can be obtained in the fourth modification, the description thereof may be omitted.

  In the above-described fourth modification, an example in which a plurality of recesses 29e is formed on the surface of the auxiliary reflection layer 29 on the resin substrate 21 side is shown. On the other hand, in this modification, an example will be described in which a plurality of recesses 29e are formed on the surface of the auxiliary reflection layer 29 on the heat dissipation plate 52 side. In this case, a region of the surface of the heat radiating plate 52 that overlaps the concave portion 29e of the auxiliary reflection layer 29 when viewed along the normal direction of the resin substrate 21 is an exposed region 52e in contact with the gas. That is, the concave portion 29 e of the reflection auxiliary layer 29 can constitute a gap portion 29 s that contacts the surface of the heat sink 52.

  In the mounting substrate 40 shown in FIG. 18, a part of the return light that has passed through the resin substrate 21 and entered the auxiliary reflection layer 29 is, as indicated by an arrow L3, between the auxiliary reflection layer 29 and the gap 29s. It can be reflected at the interface. Further, as indicated by an arrow L4, light that is not reflected at the interface between the auxiliary reflection layer 29 and the gap 29s can reach the surface of the heat dissipation plate 52 with high transmittance. For this reason, the utilization efficiency of the light in the illuminating device 55 can be made high enough.

(Other variations)
Further, in the above-described embodiment, an example in which the wiring board 20 is supplied in a rolled state or an example in which the wiring board 20 after the light emitting component 41 is mounted is wound in a roll shape is shown. However, the present invention is not limited to this, and various forms can be adopted as the supply form and storage form of the wiring board 20.

  In addition, although some modified examples with respect to the above-described embodiment have been described, naturally, a plurality of modified examples can be applied in combination as appropriate.

DESCRIPTION OF SYMBOLS 10 Mounting apparatus 20 Wiring board 21 Resin board 21a 1st surface 21b 2nd surface 21c Through-hole 21e Exposed area 22 Mounting electrode part 23 Back side wiring 24 Through-wiring 25 Corrosion prevention layer 26 Extraction electrode part 28 Reflective layer 29 Reflective auxiliary layer 29e Concave part 29s Cavity part 40 Mounting board 41 Light emitting component 42 Intermediate layer 50 Diffusion plate 52 Heat radiation plate 52e Exposed area 55 Illumination device

Claims (12)

A mounting board on which light emitting components are mounted,
A flexible resin substrate; a mounting electrode provided on the first surface of the resin substrate; and a mounting electrode provided on the second surface of the resin substrate facing the first surface. A wiring board including a wiring electrically connected to the portion;
A light emitting component mounted on the mounting electrode part,
The mounting electrode part is disposed so as to be covered by the light emitting component when viewed along the normal direction of the resin substrate,
The wiring board has a reflection characteristic of reflecting light incident from the first surface side at least partially,
In the resin substrate, a through-hole penetrating from the first surface side to the second surface side is formed,
The mounting substrate and the wiring are electrically connected via the through-hole, and a white pigment or bubbles are dispersed in the resin substrate.   The mounting substrate according to claim 1, wherein the wiring substrate further includes a corrosion prevention layer provided on the second surface of the resin substrate so as to cover the wiring. A heat sink provided on the second surface side of the resin substrate;
The mounting board according to claim 1, wherein the heat sink includes aluminum nitride or aluminum oxide. A heat sink provided on the second surface side of the resin substrate;
The mounting board according to claim 1, wherein the heat radiating plate is configured by dispersing a heat conductive filler in an insulating resin material.   The mounting substrate according to claim 3 or 4, wherein an insulating resin material is interposed between the second surface of the resin substrate and the heat dissipation plate.   The mounting substrate according to claim 5, wherein a thermally conductive filler is dispersed in the resin material interposed between the second surface of the resin substrate and the heat dissipation plate. The resin substrate includes a polyester resin, an epoxy resin, or a polyimide resin,
The mounting substrate according to claim 1, wherein the resin substrate has a thickness in a range of 10 μm to 300 μm. The wiring board further includes a reflection auxiliary layer provided on the second surface side of the resin substrate,
The reflection auxiliary layer contains an adhesive,
The mounting board further includes a heat sink attached to the wiring board via the auxiliary reflection layer,
The mounting substrate according to any one of claims 1 to 7, wherein a plurality of recesses are formed on a surface on the heat dissipation plate side of the surface of the auxiliary reflection layer. A wiring board on which light emitting components are mounted,
A flexible resin substrate;
A mounting electrode provided on the first surface of the resin substrate;
A wiring provided on a second surface facing the first surface of the resin substrate and electrically connected to the mounting electrode portion;
A light emitting component mounted on the mounting electrode part,
In the resin substrate, a through-hole penetrating from the first surface side to the second surface side is formed,
The wiring board, wherein the mounting electrode portion and the wiring are electrically connected via the through hole, and white pigments or bubbles are dispersed in the resin substrate. The wiring board further includes a reflection auxiliary layer provided in contact with the second surface of the resin substrate,
The wiring board according to claim 9, wherein the reflection auxiliary layer is configured such that a light reflectance of the reflection auxiliary layer is higher than a light reflectance of the resin substrate. The wiring board further includes a reflection auxiliary layer provided in contact with the second surface of the resin substrate,
The wiring board according to claim 9, wherein a refractive index of the auxiliary reflection layer is smaller than a refractive index of a resin material included in the resin board. The wiring board further includes a reflection auxiliary layer provided on the second surface side of the resin substrate,
The wiring substrate according to claim 9, wherein the reflection auxiliary layer is configured such that the second surface of the resin substrate partially becomes an exposed region in contact with a gas.

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