JP2021170526A - Planar light source and manufacturing method of the same - Google Patents

Abstract

To provide a planar light source which inhibits a wiring material from absorbing light emitted from a light source, and to provide a manufacturing method of the planar light source.SOLUTION: A planar light source mainly includes: a light source 20 having a pair of positive electrode and negative electrode 21 on one surface side; a light guide member 10 which covers the light source 20 so that the electrodes 21 are exposed; a wiring board 30 having a wiring layer 32 electrically connected to the electrodes 21; and a light reflection sheet 40 disposed between the light guide member 10 and the wiring board 30. The light reflection sheet 40 has first through holes 41 respectively facing the positive and negative electrodes 21 making the pair. The electrodes 21 and the wiring layer 32 are electrically connected by conductive members 50 respectively disposed through the first through holes 41.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a planar light source and a method for manufacturing the same.

A planar light source using a light emitting diode as a light source is used in many devices such as a backlight of a liquid crystal television. In order to increase the brightness and reduce the power consumption of such a planar light source, it is necessary to effectively use the light from the light source. For example, Patent Document 1 discloses a technique for improving the light extraction efficiency in a light emitting device in which wiring is exposed and a light emitting element is connected.

JP-A-2019-003994

An object of the present disclosure is to provide a planar light source that suppresses the absorption of light from a light source by a wiring material and a method for manufacturing the same.

The planar light source according to the present disclosure includes a light source having a pair of positive and negative electrodes on one surface side, a light guide member that covers the light source so that the electrodes are exposed, and a wiring layer to which the electrodes are electrically connected. A light-reflecting sheet having a first through hole that is interposed between the light guide member and the wiring board and faces each of the positive and negative electrodes, one for each electrode, is provided. And the wiring layer are electrically connected by a conductive member arranged through the first through hole.

The method for manufacturing a planar light source according to the present disclosure includes a light source having a pair of positive and negative electrodes on one surface side, a light guide member that covers the light source so that the electrodes are exposed, and one for each of the positive and negative electrodes. A light emitting module preparation step of preparing a light emitting module including a first light reflecting sheet having a first through hole facing each other, and a wiring board for preparing a wiring board having a wiring layer to which the electrodes are electrically connected. A preparatory step, a light emitting module bonding step of bonding the light emitting module to the wiring substrate, and a connecting step of electrically connecting the electrode and the wiring layer via a conductive member arranged in the first through hole. And include.

Further, in the method for manufacturing a planar light source according to the present disclosure, each of the positive and negative pairs of positive and negative electrodes is formed on a wiring substrate having a wiring layer to which the electrodes of the light source having a pair of positive and negative electrodes are electrically connected. A wiring substrate preparation step of arranging a first light-reflecting sheet having first through holes facing the electrodes one by one so that the wiring layer and the first through holes face each other, the light source, and the first. The second through hole is provided with a second light-reflecting sheet having a second through hole facing the through hole and having the second through hole on which the light source is arranged, and a light guide member covering the light source so that the electrode is exposed. A light emitting module preparation step of arranging the light source inside and preparing a light emitting module in which the light source is arranged in the light guide member, and the first light reflectivity so that the electrode faces the first through hole. The electrode and the wiring layer are electrically connected via a light source bonding step of bonding the light source module to the wiring substrate with a sheet interposed therebetween and a conductive member arranged in the first through hole. Includes connection process.

According to the present disclosure, it is possible to realize a planar light source capable of suppressing the absorption of light by the wiring material and more effectively utilizing the light emitted by the light source, and a method for manufacturing the same.

It is a schematic perspective view which shows the planar light source which concerns on 1st Embodiment. FIG. 5 is a schematic cross-sectional view taken along the line II-II shown in FIG. It is a schematic perspective view which shows an example of the light source which concerns on 1st Embodiment. It is a schematic cross-sectional view in line IIIB-IIIB shown in FIG. 3A. It is a schematic bottom view which shows the surface which has the electrode of the light source shown in FIG. 3A. It is a schematic plan view which shows the opening of the coating layer in the wiring board which concerns on 1st Embodiment. It is a schematic perspective view which shows the light emitting module which concerns on 1st Embodiment. It is a schematic plan view which shows the positional relationship between the light source and the light reflection member which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 1st Embodiment. It is the schematic sectional drawing which shows a part of the planar light source which concerns on 2nd Embodiment. It is the schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is the schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is the schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is the schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is schematic cross-sectional view which shows a part of the planar light source which concerns on 3rd Embodiment. It is a schematic perspective view which shows the light emitting module which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is the schematic sectional drawing which shows the modification of the light source. It is the schematic sectional drawing which shows the modification of the light source. It is the schematic sectional drawing which shows the modification of the light source. It is the schematic sectional drawing which shows the modification of the light source. It is a schematic perspective view which shows the modification of the light guide member. It is the schematic sectional drawing which shows the modification of the light guide member. It is the schematic sectional drawing which shows the modification of the light guide member. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on the modification of the light guide member. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on the modification of the light guide member. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on the modification of the light guide member. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on the modification of the light guide member. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on the modification of the light guide member. It is schematic cross-sectional view which shows an example of the manufacturing method which concerns on the modification of the light guide member. It is a schematic cross-sectional view which shows the planar light source which includes the wiring board which concerns on the modification of this Embodiment. It is a flowchart which shows the manufacturing method of the planar light source which concerns on this embodiment.

Hereinafter, a planar light source and a method for manufacturing the same according to the embodiment will be described with reference to the drawings. Since the drawings referred to in the description relating to the following embodiments schematically show the embodiments, the scale, spacing, positional relationship, etc. of each member are exaggerated, and some of the members are omitted. Alternatively, an end view showing only the cut surface may be used as the cross-sectional view. Further, in the following description, in principle, the same or the same quality members are shown for the same name and reference numeral, and detailed description thereof will be omitted as appropriate. In the present specification, "top", "bottom", etc. indicate relative positions between components in the drawings referred to for explanation, and indicate absolute positions unless otherwise specified. Not intended.

[First Embodiment]
(Spherical light source)
An example of the configuration of the planar light sources 200 and 300 according to the first embodiment will be described with reference to FIGS. 1 to 4. The planar light source 200 whose cross section is shown in FIG. 2 has a configuration corresponding to a part 200A of the planar light source 300. The planar light source 200 and the planar light source 300 differ in the number of light emitting modules described later, and have the same configuration for one light emitting module.
The planar light source 300 includes a light source 20 having a pair of positive and negative electrodes 21 on one surface, a light guide member 10 that covers the light source 20 so that the electrodes 21 are exposed, and a wiring layer 32 to which the electrodes 21 are electrically connected. It mainly includes a wiring substrate 30 to be provided, and a light-reflecting sheet 40 interposed between the light source member 10 and the wiring substrate 30. The light reflective sheet 40 has one first through hole 41 facing the electrode 21 for each of the positive and negative pairs of the light source 20, that is, one for each electrode 21, and the electrode 21 and the wiring layer. The 32 is electrically connected to the conductive member 50 arranged through the first through hole 41.
Hereinafter, each configuration of the planar light source 300 will be described. The light extraction surface of the planar light source 300 is the upper surface of the light guide member 10 located on the opposite side of the light reflective sheet 40. In this embodiment, the light adjusting member 60 is arranged on the upper surface of the light guide member 10.

(light source)
As shown in FIGS. 2 to 3C, the light source 20 has a pair of positive and negative electrodes 21 on one surface side, and a voltage is applied from the outside through the electrodes 21 to emit light. As shown in FIGS. 3A to 3C, the light source 20 includes a light emitting element 22, a translucent member 23A, and a first light adjusting member 24A. The light source 20 has a shape close to a rectangular parallelepiped, and is provided with a pair of positive and negative electrodes 21 so as to be exposed on the lower surface opposite to the upper surface on which the first light adjusting member 24A of the translucent member 23A is arranged.

The light emitting element 22 includes a semiconductor laminate, and in the present embodiment, at least the upper surface and the side surface of the semiconductor laminate are surrounded by the translucent member 23A. The semiconductor laminate is configured to be capable of emitting visible light or ultraviolet light, and any composition can be used depending on the desired emission peak wavelength. For example, a nitride semiconductor (In _x Al _y Ga _1-xy N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) or GaP capable of emitting blue or green light, or GaAlAs capable of emitting red light. Or AlInGaP or the like can be used. In addition, the size, number, and the like of the light emitting elements 22 can be appropriately selected according to the purpose of use.

The semiconductor laminate includes an n-type semiconductor layer and a p-type semiconductor layer, and a light emitting layer sandwiched between them. The light emitting layer may have a structure such as a double heterojunction or a single quantum well (SQW), or may have a structure having a group of active layers such as a multiple quantum well (MQW). good.
Further, the semiconductor laminate may have a structure including one or more light emitting layers between the n-type semiconductor layer and the p-type semiconductor layer, or the n-type semiconductor layer, the light emitting layer and the p-type semiconductor layer. The structure including and in order may have a structure in which the structure is repeated a plurality of times. When the semiconductor laminate includes a plurality of light emitting layers, it may include light emitting layers having different emission peak wavelengths, or may include light emitting layers having the same emission peak wavelength. The same emission peak wavelength includes a case where there is a variation of about several nm. The combination of emission peak wavelengths between the plurality of light emitting layers can be appropriately selected. For example, when the semiconductor laminate contains two light emitting layers, blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or , The light emitting layer can be selected by a combination of green light and red light. Each light emitting layer may include a plurality of active layers having different emission peak wavelengths, or may include a plurality of active layers having the same emission peak wavelength.

The translucent member 23A is made of, for example, a translucent resin material, and an epoxy resin, a silicone resin, a resin in which these are mixed, or the like can be used. The translucent member 23A may include a phosphor, for example, by including a phosphor that absorbs blue light from the light emitting element 22 and emits yellow light, white light is emitted from the light source 20. It can be emitted. Further, the translucent member 23A may include a plurality of types of phosphors, for example, a phosphor that absorbs blue light from the light emitting element 22 and emits yellow light, and red light. White light can also be emitted from the light source 20 by including a radiating phosphor. Examples of such a phosphor include an yttrium aluminum garnet-based phosphor (for example, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce) and a lutetium aluminum garnet-based phosphor (for example, Lu ₃ (Al)). , Ga) ₅ O ₁₂ : Ce), terbium aluminum garnet-based phosphor (for example, Tb ₃ (Al, Ga) ₅ O ₁₂ : Ce), CCA-based phosphor (for example, Ca ₁₀ (PO ₄ ) ₆ C) _l2 : Eu), SAE-based phosphors (eg, Sr ₄ Al ₁₄ O ₂₅ : Eu), chlorosilicate-based phosphors (eg, Ca ₈ MgSi ₄ O ₁₆ C _l2 : Eu), β-sialon-based phosphors (eg, eg) (Si, Al) ₃ (O, N) ₄ : Eu), α-sialon-based phosphor (for example, Mz (Si, Al) ₁₂ (O, N) ₁₆ : Eu (where 0 <z ≦ 2). M is Li, Mg, Ca, Y, and a lanthanide element excluding La and Ce)), SLA-based phosphor (for example, SrLiAl ₃ N ₄ : Eu), CASN-based phosphor (for example, CaAlSiN ₃ : Eu) or SCASN. system phosphors _{(e.g., (Sr, Ca) AlSiN 3} : Eu) nitride phosphor such as, KSF phosphor _{(e.g., K 2 SiF 6: Mn)} , KSAF phosphor _(e.g., K 2 (Si , Al) F ₆ : Mn) or MGF-based phosphors (for example, 3.5 MgO, 0.5 MgF ₂ , GeO ₂ : Mn) and other fluoride-based phosphors, and phosphors having a perovskite structure (for example, CsPb (F)). , Cl, Br, I) ₃ ), or quantum dot phosphors (eg, CdSe, InP, AgInS ₂ or AgInSe ₂ ) and the like can be used.

Further, the wavelength conversion sheet containing the above-mentioned phosphor may be arranged on the planar light sources 200 and 300. The wavelength conversion sheet can be a planar light source that absorbs a part of the blue light from the light source 20 and emits yellow light, green light and / or red light, and emits white light. For example, white light can be obtained by combining a light source capable of emitting blue light and a wavelength conversion sheet containing a phosphor capable of emitting yellow light. In addition, a light source capable of emitting blue light and a wavelength conversion sheet containing a red phosphor and a green phosphor may be combined. Further, a light source capable of emitting blue light and a plurality of wavelength conversion sheets may be combined. As the plurality of wavelength conversion sheets, for example, a wavelength conversion sheet containing a phosphor capable of emitting red light and a wavelength conversion sheet containing a phosphor capable of emitting green light can be selected. Further, a light source having a light emitting element capable of emitting blue light, a translucent member containing a phosphor capable of emitting red light, and a wavelength conversion sheet containing a phosphor capable of emitting green light are combined. You may.

The first light adjusting member 24A is a member for adjusting the light distribution of the light source 20. The first light adjusting member 24A blocks or reflects a part of the light passing from the inside to the outside of the light source 20 through the upper surface of the light source 20. The light distribution of the light source 20 is adjusted via the first light adjusting member 24A as the light extraction surface of the planar light source 300 so that the light emitted directly above the surface does not become too strong and the light emitted over the entire surface becomes uniform. .. When the transmittance of the first light adjusting member 24A with respect to the light emitted from the light emitting element 22 is sufficiently low, for example, when it is 1% or more and 50% or less, preferably 3% or more and 30% or less, the first light adjusting member 24A It becomes a light-shielding film, and it is possible to prevent the brightness directly above the light source 20 from becoming too high. As the first light adjusting member 24A, for example, a resin material containing a light diffusing material may be used, or a metal material may be used. For example, as the resin material, a silicone resin, an epoxy resin, a resin in which these are mixed, or the like can be used. Further, as the light diffusing material, for example, a known material such as titania, silica, alumina, zinc oxide or glass can be used. Further, as the first light adjusting member 24A, a multilayer film (dielectric multilayer film) made of a dielectric obtained by laminating a plurality of two or more kinds of dielectrics can be used.

(Light guide member)
As shown in FIGS. 1 and 2, the light guide member 10 is a member having translucency for extracting light from the light source 20 as planar light from the upper surface serving as a light extraction surface of the planar light source 300. .. The lower surface of the light guide member 10 is arranged so as to face the light reflective sheet 40, except for the light source arrangement portion 11 in which the light source 20 is arranged. In other words, the light-reflecting sheet 40 faces the lower surface of the light guide member 10 and the lower surface of the light source 20, suppresses the absorption of light by the wiring layer 32 and the like, and can effectively use the light of the light source 20. .. The height of the light guide member 10 in the direction perpendicular to the light reflecting sheet 40 is equal to or higher than the height of the light source 20, and may exceed the height of the light reflecting member 70 described later. The height of such a light guide member 10 is preferably, for example, about 200 μm or more and 800 μm or less.
The light source 20 is arranged on the lower surface side of the light guide member 10 so that the electrodes 21 are exposed. The recess of the light guide member 10 in which the light source 20 is arranged is the light source arrangement portion 11. The light guide member 10 covers the upper surface and the side surface of the light source 20 arranged in the light source arrangement portion 11.

The material of the light guide member 10 includes, for example, a thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate or polyester, a resin material such as a thermosetting resin such as an epoxy resin or a silicone resin, or a light-transmitting material such as glass. A material having a property can be used. In particular, it is preferable to use polycarbonate, which has high transparency and is inexpensive.

The upper surface of the light guide member 10 may have a convex portion and / or a concave portion in a region having low brightness, for example, in order to reduce uneven brightness.

(Light reflective sheet)
The light-reflecting sheet 40 is a sheet-like member that reflects light toward the light extraction surface side of the planar light source 300. The light reflective sheet 40 is arranged between the light guide member 10 and the wiring board 30 described later, and has one first through hole 41 facing the electrode 21 for each electrode 21.
If the opening of the first through hole 41 has a size that can include the entire one electrode 21 inside the opening in a plan view, it is easy to electrically connect the electrode 21 and the conductive member 50 described later. However, the larger the opening of the first through hole 41, the smaller the light-reflecting sheet 40 at the position facing the light source 20. Therefore, the area of the wiring layer 32 or the like in which the light from the light source 20 is irradiated through the first through hole 41 becomes large. Then, when the wiring layer 32 and the like are irradiated with light, the chances of the light being absorbed increase. Therefore, in a plan view, the opening of the first through hole 41 should be made smaller so that the shape of the opening of the first through hole 41 substantially matches the shape of the electrode 21 or is located inside the outer edge of the electrode 21. Is preferable. Further, it is preferable that the opening of the first through hole 41 does not protrude outside the outer edge of the light source 20 in a plan view. In other words, the opening of the first through hole 41 is preferably located inside the outer edge of the light source 20 in a plan view. As a result, it is possible to reduce the light from the light source 20 being absorbed by the conductive member 50 arranged in the first through hole 41.

The light-reflecting sheet 40 preferably has a high reflectance in order to effectively utilize light. The reflectance of the light-reflecting sheet 40 is preferably, for example, 90% or more, more preferably 94% or more, at the wavelength of the light emitted by the light source 20.
As the light reflective sheet 40, a resin sheet containing a large number of bubbles (for example, a foamed resin sheet), a resin sheet containing a light diffusing material, or the like can be used. Examples of the resin used for the light-reflecting sheet 40 include thermoplastic resins such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, polyethylene naphthalate resin and polyester resin, epoxy resin and silicone resin, and the like. The thermocurable resin of the above can be used. Further, as the light diffusing material, for example, a known material such as titania, silica, alumina, zinc oxide or glass can be used.

(Second light adjustment member)
The planar light source 300 includes a light adjusting member (second light adjusting member) 60 arranged on the light guide member 10 so as to face the light source 20 via the light guide member 10.
The second light adjusting member 60 is a member for weakening the light directly above the light source 20 on the light extraction surface of the planar light source 300 to bring the brightness of the light extraction surface closer to uniform. The transmittance of the second light adjusting member 60 is preferably, for example, 20% or more and 60% or less, and more preferably 30% or more and 40% or less with respect to the light from the light source 20. Similar to the first light adjusting member 24A, the second light adjusting member 60 can use a material that reflects light, such as a resin material containing a light diffusing material or a metal material. The second light adjusting member 60 in the present embodiment covers the entire light source 20 in a plan view, and its outer edge has a circular shape, but it may have a rectangular shape. Further, the second light adjusting member 60 is in the form of a film in the present embodiment, but may be in the form of dots.

(Light reflecting member)
The planar light source 300 includes a light reflecting member 70 that surrounds the light source 20 in a rectangular frame shape in a plan view at a position away from the light source 20.
The light reflecting member 70 is a member that reflects the light from the light source 20 toward the light extraction surface side of the planar light source 300 and takes it out. The light reflecting member 70 has a predetermined height and is arranged on the light reflecting sheet 40 along the outer circumference of the light guide member 10. By partitioning the light guide member 10 for each light source 20 by the light reflecting member 70, it is possible to suppress light guiding between adjacent compartments. This enables local dimming to control the light emitting area on a section-by-section basis.
It is preferable that the height of the light reflecting member 70 in the direction perpendicular to the light reflecting sheet 40 is equal to or higher than the height of the light source 20. In a plan view, the length of one side of the light reflecting member 70, which has a rectangular frame shape, is larger than the length of one side of the light source 20, and is, for example, in the range of 5 to 30 times.

In the present embodiment, the inner surface of the light reflecting member 70 is curved convexly toward the light source 20, but may be curved concavely. In particular, the cross-sectional shape of the light-reflecting member 70 is preferably narrower as the distance from the light-reflecting sheet 40 in the height direction increases, whereby the light from the light source 20 is taken out from the light source 300. It can be efficiently taken out to the side. The inner surface of the light reflecting member 70 may be a single plane, a single curved surface, a combination of planes having different inclinations with respect to the light reflecting sheet 40, a combination of a plurality of curved surfaces having different curvatures, or a flat surface. And a curved surface may be used.
The reflectance of the light reflecting member 70 with respect to the light from the light source 20 is preferably, for example, 60% or more, and more preferably 90% or more. As the light reflecting member 70, for example, a resin containing a light diffusing material can be used. As the resin used for the light reflecting member 70, a thermoplastic resin such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin or polyester resin, or a thermosetting resin such as epoxy resin or silicone resin may be used. can. Further, as the light diffusing material, known materials such as titania, silica, alumina, zinc oxide and glass can be used.

(Wiring board)
The wiring board 30 includes an insulating base material 34, a wiring layer 32 arranged on the insulating base material 34 and to which a pair of positive and negative electrodes 21 are electrically connected, and a coating layer 36 covering the wiring layer 32. The wiring board 30 has a third through hole 31 that communicates with each of the first through holes 41 and penetrates the wiring layer 32.
As the wiring board 30, for example, a rigid board or a flexible board can be used.
The surface of the wiring board 30 on the side where the light source 20 is not arranged is the first surface, and the surface opposite to the first surface is the second surface.

The wiring layer 32 is a member that serves as a path for applying a voltage to the light source 20. As shown in FIG. 4, for example, the shape of the wiring layer 32 at the portion where the third through hole 31 is arranged can be made wider than other linear wiring layers.
A metal material can be used for the wiring layer 32, for example, a single metal such as Ag, Al, Ni, Rh, Au, Cu, Ti, Pt, Pd, Mo, Cr, W, an alloy containing these metals, or an alloy containing these metals. A conductive paste containing these metal powders can be preferably used. As the shape of the metal powder, for example, a spherical shape, a flake shape, a needle shape, or the like can be used.

The wiring layer 32 is arranged on the insulating base material 34.
The material of the insulating base material 34 is, for example, an insulating resin material such as a phenol resin, an epoxy resin, a polyimide resin, a BT resin, or a polyphthalamide. As the insulating base material 34, a ceramic material such as alumina or aluminum nitride may be used. Further, the insulating base material 34 may have insulating members arranged in layers on the surface of the metal member.

The coating layer 36 is a member that protects the wiring layer 32. The coating layer 36 may be arranged so as to cover the entire insulating base material 34. In the first embodiment, the covering layer 36 has an opening 37 so that the third through hole 31 and the wiring layer 32 arranged around the third through hole 31 are exposed, as shown in FIG. 4, for example. As the material of the coating layer 36, an insulating material is used, for example, polyimide.

(Conductive member)
The conductive member 50 is a member that electrically connects the electrode 21 and the wiring layer 32.
As described above, the light reflective sheet 40 is provided with the first through hole 41 so as to face each of the positive and negative electrodes 21 of the light source 20 so as to face each other, and the wiring board 30 has the first through hole 41. A third through hole 31 is arranged in communication with each of them. That is, from the electrode 21 to the wiring layer 32, there is a path between the electrode 21 and the wiring layer 32 that makes one of the electrodes 21 and one of the third through holes 31 have a one-to-one correspondence. The conductive member 50 is arranged in each of the paths to electrically connect the electrode 21 and the wiring layer 32.
As the material of the conductive member 50, in addition to the same material as the wiring layer 32, known materials such as tin-silver-copper (SAC) -based solder and tin-bismuth (SnBi) -based solder can be used.

In the planar light source 300, the electrical contacts between the wiring layer 32 and the conductive member 50 are arranged inside the third through hole 31 and on the surface of the wiring layer 32 opposite to the surface of the wiring layer 32 on the light reflective sheet 40 side. Will be done. Here, the surface of the wiring layer 32 opposite to the surface of the light-reflecting sheet 40 is the first surface of the wiring board 30. On the first surface side of the wiring board 30, for example, as shown in FIG. 4, the third through hole 31 overlaps with the wiring layer 32 in a plan view, in other words, the third through hole 31 is inside the outer edge of the wiring layer 32. It is located at the position of. The contact points between the wiring layer 32 and the conductive member 50 are the portion where the wiring layer 32 is exposed on the inner surface of the third through hole 31 (the inner surface of the through hole of the wiring layer 32) and the periphery of the third through hole 31. It is arranged on the wiring layer 32 and can ensure an electrical connection. Further, the inner side surface of the third through hole 31 in the present embodiment is arranged so that the inner side surface of the through hole of the wiring layer 32 and the inner side surface of the through hole of the insulating base material 34 are flush with each other. The inner side surface of the through hole of the wiring layer 32 may be arranged outside the inner side surface of the through hole of the insulating base material 34. That is, in a plan view, the width of the through hole of the wiring layer 32 may be larger than the width of the through hole of the insulating base material 34. Further, the wiring layer 32 may be arranged so as to surround the entire circumference of the through hole of the insulating base material 34 as in the present embodiment in a plan view, but the wiring layer 32 may be arranged around the through hole of the insulating base material 34. It may be arranged in a part.

(Protective member)
In addition to the above configuration, the planar light source 300 may include a protective member 80 that covers the opening 37 of the coating layer 36 of the wiring board 30. The protective member 80 has an insulating property and is a member that protects the wiring layer 32 and the conductive member 50 from being short-circuited.
As the protective member 80, a phenyl silicone resin, a dimethyl silicone resin, an epoxy resin, an acrylic resin, a urethane resin, or the like can be used. Further, the protective member 80 may have translucency, or may be made translucent by adding a pigment such as titanium oxide. In particular, it is preferable that the protective member 80 has translucency so that the connection state between the wiring layer 32 and the conductive member 50 can be visually recognized.

According to the planar light source 300 having the configuration described above, the light reflective sheet 40 is arranged through the first through hole 41 so as to face each of the positive and negative electrodes 21 of the light source 20 one by one. , The conductive member 50 is connected to the electrode 21. Therefore, in the planar light source 300, the entire lower surface of the light source 20 excluding the electrode 21 faces the light reflective sheet 40, and the light of the light source 20 can be effectively used. Further, since the positive and negative pairs of electrodes 21 are arranged separately, as shown in FIG. 3C, the positive and negative electrodes of one light source 20 are on the lower surface of the light source 20 regardless of the shape and arrangement of the electrodes 21. There is a region 25 between 21. Since this region 25 also faces the light-reflecting sheet 40, the light from the light source 20 can be further effectively used. In this way, the planar light source 300 can increase the area of the light-reflecting sheet 40 facing the light source 20, and can reduce the area of the wiring layer 32 and the like irradiated with light. Therefore, the planar light source 300 can suppress the absorption of light by the wiring layer 32 and the like, and can effectively use the light of the light source 20.

The number of light sources 20 arranged on the wiring board 30 may be one or a plurality. The number of light sources 20 can be appropriately selected according to the size and shape of the planar light source 300. Further, the distance between the light sources 20 can be adjusted as appropriate.

(Manufacturing method of planar light source according to the first embodiment)
Next, an example of the method for manufacturing the planar light source 300 according to the first embodiment will be described with reference to FIGS. 1 to 9C and 22.
The method for manufacturing the planar light source 300 is a light source 20 having a pair of positive and negative electrodes 21 on one surface side, a light guide member 10 covering the light source 20 so that the electrodes 21 are exposed, and each electrode forming a positive and negative pair of the light source 20. A light emitting module preparation step S1 for preparing a light emitting module 100 including a first light reflecting sheet 40 having a first through hole 41 facing each of 21 and a wiring layer 32 to which the electrodes 21 are electrically connected are provided. The wiring board preparation step S2 for preparing the wiring board 30 to be held, the light emitting module bonding step S3 for adhering the light emitting module 100 to the wiring board 30, and the electrode 21 and the wiring via the conductive member 50 arranged in the first through hole 41. The connection step S4 for electrically connecting the layer 32 is included. Here, either the light emitting module preparation step S1 or the wiring board preparation step S2 may be performed first or at the same time.

(Light emitting module preparation process)
The light emitting module preparation step S1 is a step of preparing a light emitting module 100 including at least a light source 20, a light guide member 10, and a first light reflective sheet 40. The planar light source 300 is configured by combining the light emitting module 100 or a unit in which a plurality of light emitting modules 100 are aligned as shown in FIG. 5 with the wiring board 30 in the process of the manufacturing method. The light emitting module 100 in this embodiment further includes a light reflecting member 70 and a light adjusting member (second light adjusting member) 60.
Further, here, a case where a plurality of light emitting modules 100 are formed by forming an aggregate of the light emitting modules 100 and then individualizing the aggregates will be described. Here, the individualization includes a case of separating so as to include one light source 20 and a case of separating so as to include two or more light sources 20. Then, the separated light emitting modules can be bonded to the wiring board 30 in the light emitting module bonding step described later.

First, as shown in FIG. 7A, a first through hole 41 is provided in the light reflecting sheet so that one first through hole 41 corresponds to one electrode 21 of the light source 20, and the first light reflecting sheet is provided. Form 40. That is, in this example, two first through holes 41 are provided for one light source 20. The first through hole 41 can be formed by punching, for example, using a punch that substantially matches the shape of the electrode 21 in a plan view. In addition to punching, the first through hole 41 can also be formed by using, for example, a drill or a laser. Alternatively, a light-reflecting sheet having the first through hole 41 may be purchased.
Next, as shown in FIG. 7B, the light source 20 is arranged on the first light-reflecting sheet 40 so that the first through hole 41 and the electrode 21 face each other. The region 25 between the pair of positive and negative electrodes 21 on the surface of the light source 20 having the electrodes 21 faces the first light reflective sheet 40.

Subsequently, as shown in FIG. 7C, the light reflecting member 70A is arranged so as to surround the light source 20 at a certain distance. As shown in FIG. 6, the light reflecting member 70A has a grid pattern in a plan view. Each lattice of the light reflecting member 70A is arranged so as to surround one light source 20 as a center. The light reflecting member 70A can be formed, for example, by applying the material of the light reflecting member 70A having an appropriate viscosity on the first light reflecting sheet 40. The cross section of the light reflecting member 70A has, for example, a shape obtained by cutting an ellipse in half with a short diameter, but may have a triangular shape or a rectangular shape, for example.

Subsequently, as shown in FIG. 7D, the light guide member 10 is arranged so as to cover the light source 20. The light guide member 10 can be arranged, for example, by injecting a resin as a material of the light guide member 10 into a region surrounded by a frame composed of the light reflecting member 70A and curing the light guide member 10. The resin may be injected from the nozzle of the dispenser, may be applied by screen printing or spraying, or may be used in combination. The pre-arranged position of the light source 20 becomes the light source arrangement portion 11 in the light guide member 10 as a result in this manufacturing method. Since the lower surface of the light source 20 is not covered with the light guide member 10, the electrode 21 faces the first through hole 41 of the first light reflective sheet 40 in a state of being exposed from the light guide member 10. The entire lower surface of the light source 20 excluding the electrode 21 faces the first light-reflecting sheet 40, and the light from the light source 20 can be effectively used. The light guide member 10 can be prepared by being molded by injection molding or transfer molding, or the molded one may be purchased and prepared.

Subsequently, as shown in FIG. 7E, the light adjusting member 60 is arranged on the light guide member 10 so as to face the light source 20 via the light guide member 10. The light adjusting member 60 can be formed, for example, by applying a resin used as a material for the light adjusting member 60 on the light guide member 10 and curing the light adjusting member 60. At this stage, an aggregate 150 of light emitting modules 100 before individualization is formed.
Then, as shown in FIG. 7F, the aggregate 150 of the light emitting module 100 is cut by the grid line 70B of the light reflecting member 70A and separated into individual pieces. Cutting can be performed by a known method using, for example, a dicing blade or a laser. In this way, a plurality of light emitting modules 100 can be formed.

(Wiring board preparation process)
The wiring board preparation step S2 is a step of preparing the wiring board 30 for adhering the light emitting module 100. Here, the wiring board 30 forms a third through hole 31 that communicates with each of the first through holes 41 and penetrates the wiring layer 32. A cross-sectional view of the wiring board 30A before forming the third through hole 31 is shown in FIG. 8A. A cross-sectional view of the wiring board 30 after the formation of the third through hole 31 is shown in FIG. 8B.
First, the wiring layer 32A is arranged on the insulating base material 34A, and the coating layer 36 is arranged so as to cover the wiring layer 32A to form the wiring board 30A. As shown in FIG. 4, the coating layer 36 forms an opening 37 so that the place where the third through hole 31 is formed and the periphery thereof are exposed, as shown in FIG. 4, in order to arrange the conductive member 50 in a later step. Keep it.
Next, the third through hole 31 is formed in the wiring board 30A before the formation of the third through hole 31 so as to communicate with each of the first through holes 41 of the first light reflective sheet 40 and penetrate the wiring layer 32. Form. The third through hole 31 can be formed by, for example, punching, drilling, or processing with a laser. In the wiring board preparation step S2, a wiring board in which the wiring layer and the coating layer are formed as described above and has the third through hole 31 may be purchased and prepared.

(Light emitting module bonding process)
The light emitting module bonding step S3 is a step of bonding the wiring board 30 and the light emitting module 100.
As shown in FIG. 9A, an adhesive resin is applied to the surface of the wiring board 30 to which the light emitting module 100 is adhered, and the first through hole 41 and the third through hole 31 are aligned so as to face each other, and the light emitting module is aligned. Glue 100. The adhesive resin is not shown. As the adhesive resin, for example, a known resin containing an acrylic resin, an epoxy resin, or a urethane resin as a component can be used. In FIG. 9A, adjacent light emitting modules 100 are in close contact with each other. However, the interval between the light emitting modules 100 may be, for example, about 1% to 10% of the width of the light emitting module 100, and can be appropriately set.

In the wiring substrate 30 to which the light emitting module 100 is adhered, the third through hole 31 communicates with the first through hole 41 of the first light reflective sheet 40 when viewed from the surface on which the light emitting module 100 is not adhered. The tip of the through hole 41 is closed by the electrode 21 of the light source 20. That is, as many holes as the number of electrodes 21 are formed with the electrode 21 as the bottom and the third through hole 31 as the inlet.

(Connection process)
The connection step S4 is a step of electrically connecting the electrode 21 and the wiring layer 32 by the conductive member 50. FIG. 9B shows a cross-sectional view at the end of the connection step S4.
First, the conductive member 50 is injected into the hole having the third through hole 31 as an inlet. When injecting the conductive member 50, the wiring board 30 to which the light emitting module 100 is adhered is placed horizontally, and the light emitting module 100 side is turned down. The conductive member 50 needs to have an amount that can sufficiently reach the electrode 21 which is the bottom of the hole and at the same time secure a contact point with the wiring layer 32 inside the third through hole 31. The conductive member 50 further injects an amount that spreads to the surface of the wiring layer 32 outside the third through hole 31. That is, the contact point in the electrical connection between the conductive member 50 and the wiring layer 32 is also provided on the surface of the wiring layer 32 opposite to the surface on the first light reflective sheet 40 side. The electrical connection with the wiring layer 32 is more secure.
After injecting the conductive member 50, a step of heating the conductive member 50 (for example, a reflow method) is performed. The conductive member 50 may be provided separately for each hole as in the present embodiment, or may be provided so as to be continuous between adjacent holes, and a laser or the like may be provided before or after heating the conductive member 50. It may be used to separate each hole. Further, the conductive member 50 may be injected from the nozzle of the dispenser, may be provided by screen printing, or may be screen-printed after being injected from the nozzle, or may be used in combination with nozzle injection and screen printing.

(Protective member forming process)
In addition to the above steps, a protective member forming step S5 may be further performed. The protective member forming step S5 is a step of forming the protective member 80 that covers the conductive member 50 and the exposed wiring layer 32. As shown in FIG. 9C, in the protective member forming step S5, the protective member 80 is formed so as to cover the covering layer 36 around the opening 37.

As described above, by preparing the light emitting module 100 and the wiring board 30 separately, each process can be carried out simultaneously or independently, so that the efficiency of the manufacturing process can be improved. In this manufacturing method, since the light emitting module 100 or the unit in which a plurality of light emitting modules 100 are aligned is adhered to the wiring board 30, it is easy to adjust the interval and the number of the light emitting modules 100.

[Second Embodiment]
The configuration of the planar light source according to the second embodiment will be described with reference to FIG. 10 as a planar light source 201 having one light emitting module.
The planar light source 201 has a different conductive member structure from the planar light source 200 according to the first embodiment. Other configurations are common to the first embodiment. The description of the parts common to the first embodiment will be omitted as appropriate.

(1st conductive member and 2nd conductive member)
The conductive member of the planar light source 201 includes a first conductive member 51 arranged in the first through hole 41 and a second conductive member 52 arranged between the first conductive member 51 and the wiring layer 32. Be prepared. Then, the electrode 21 and the wiring layer 32 are electrically connected to each other via the first conductive member 51 and the second conductive member 52.
The first conductive member 51 may be arranged in the first through hole 41 so as to be flat with the surface of the light reflective sheet 40, or may be arranged so as to be lower than the surface of the light reflective sheet 40. It may be arranged so as to protrude from the first through hole 41. As the material of the first conductive member 51 and the second conductive member 52, the same material as the conductive member 50 described in the first embodiment can be used. As the material of the first conductive member 51 and the second conductive member 52, the same material may be used, or different materials may be used.

In the planar light source 201, the entire lower surface of the light source 20 excluding the electrode 21 faces the light-reflecting sheet 40, and the light from the light source 20 can be effectively used. The shape of the first conductive member 51 on the light source 20 side can be adjusted according to the shape of the electrode 21. Further, for the first conductive member 51, a material suitable for the bondability with the electrode 21 can be selected.

(Manufacturing method of planar light source according to the second embodiment)
An example of the method for manufacturing a planar light source according to the second embodiment will be described with reference to FIGS. 11A to 12B and 22. The drawing shows an example of combining a plurality of light emitting modules with a wiring board.
The method for manufacturing a planar light source according to the second embodiment is different from the method for manufacturing a planar light source according to the first embodiment already described in the light emitting module preparation step S12 and the connection step S42. Other than that, it is common to the manufacturing method of the first embodiment.

(Connection process)
In the connection step S42 in the method for manufacturing a planar light source according to the second embodiment, the electrodes 21 and the wiring layer 32 are connected to each other via a conductive member arranged in advance in the first through hole 41 of the first light reflective sheet 40. Connect electrically. The conductive member arranged in advance in the first through hole 41 is the first conductive member 51, and the conductive member arranged between the first conductive member 51 and the wiring layer 32 is the second conductive member 52.
The step of providing the first conductive member 51 is performed in the light emitting module preparation step S12. As shown in FIGS. 11A and 11B, the first conductive member 51 is provided in the first through hole 41 of the first light reflective sheet 40 before the light source 20 is arranged. The first conductive member 51 and the electrode 21 of the light source 20 are joined by using solder or the like. The step of providing the second conductive member 52 is performed after the light emitting module 101 is adhered to the wiring board 30 as shown in FIGS. 12A and 12B. The light emitting module preparation step S12 is the same as the light emitting module preparation step S1 in the first embodiment except that the first conductive member 51 is provided.

In the manufacturing method of the second embodiment, by providing the conductive member in the first through hole 41 in advance, the other steps can be proceeded in the same manner as in the first embodiment. Therefore, this manufacturing method can form the planar light source according to the second embodiment while taking advantage of the manufacturing method of the first embodiment.

[Third Embodiment]
An example of the configuration of the planar light source according to the third embodiment will be described with reference to FIG. 13 as a planar light source 202 having one light emitting module.
The planar light source 202 has a different structure of the light reflective sheet from the planar light source 200 according to the first embodiment. Other configurations are common to the first embodiment. The description of the parts common to the first embodiment will be omitted as appropriate.

(1st light reflective sheet and 2nd light reflective sheet)
The light-reflecting sheet of the planar light source 202 has a first light-reflecting sheet 40 having a first through hole 41 and a second through hole 46 facing the first through hole 41 and in which the light source 20 is arranged. A second light reflective sheet 45 is provided.
Similar to the planar light source 200 according to the first embodiment, the planar light source 202 has the entire lower surface of the light source 20 excluding the electrode 21 facing the first light reflective sheet 40, and effectively utilizes the light of the light source 20. be able to. Then, in the planar light source 202, the area of the wiring layer 32 or the like irradiated with light can be reduced by facing the region 25 between the electrodes 21 of the light source 20 and the first light reflective sheet 40. .. Further, in the planar light source 202, the first light reflecting sheet 40 and the second light reflecting sheet 45 are arranged so as to overlap each other around the light source 20. By arranging the light-reflecting sheets in an overlapping manner, the planar light source 202 can further reduce the irradiation of light to the wiring layer 32 and the like.

(Manufacturing method of planar light source according to the third embodiment)
An example of the method for manufacturing the planar light source according to the third embodiment will be described with reference to FIGS. 14 to 17C and 22. The drawing shows an example of combining a plurality of light emitting modules with a wiring board.
In the method for manufacturing a planar light source according to the third embodiment, the light source 20 is formed on a wiring substrate 30 having a wiring layer 32 to which the electrodes 21 of the light source 20 having a pair of positive and negative electrodes 21 on one surface side are electrically connected. A wiring board preparation step of arranging a first light-reflecting sheet 40 having a first through hole 41 facing each of a pair of positive and negative electrodes 21 so that the wiring layer 32 and the first through hole 41 face each other. The light source 20 is covered with S2A, the light source 20, the second light reflective sheet 45 facing the first through hole 41 and having the second through hole 46 in which the light source 20 is arranged, and the electrode 21 so as to be exposed. The light emitting module preparation step S1A, which includes the light guide member 10 and prepares the light source 102 in which the light source 20 is arranged in the second through hole 46 and the light source 20 is arranged in the light guide member 10, and the electrode 21 are the first. The light source bonding step S3A for adhering the light source module 102 to the wiring substrate 30 by interposing the first light reflective sheet 40 so as to face the first through hole 41, and the conductive member 50 arranged in the first through hole 41. The connection step S4 for electrically connecting the electrode 21 and the wiring layer 32 via the light source 21 is included. Here, either the light emitting module preparation step S1A or the wiring board preparation step S2A may be performed first or at the same time.

(Light emitting module preparation process)
The light emitting module preparation step S1A is a step of preparing a light emitting module 102 including at least a light source 20, a light guide member 10, and a second light reflective sheet 45. The planar light source 202 is configured by combining a unit in which a plurality of light emitting modules 102 or light emitting modules 102 are arranged as shown in FIG. 14 with the first light reflective sheet 40 and the wiring board 30 in the process of the manufacturing method. Will be done. The light emitting module 102 in this embodiment further includes a light reflecting member 70 and a light adjusting member (second light adjusting member) 60.
Here, a case will be described in which a plurality of light emitting modules 102 are formed by forming an aggregate of the light emitting modules 102 and then disassembling the aggregate. Here, too, the individualization includes a case of separating so as to include one light source 20 and a case of separating so as to include two or more light sources 20. Then, the separated light emitting modules can be bonded to the wiring board 30 in the light emitting module bonding step described later.

First, as shown in FIG. 15A, a second through hole 46 in which the light source 20 is arranged is formed in the second light reflective sheet 45. The formation of the second through hole 46 can be performed by punching, for example, using a punch having a shape similar to the shape of the light source 20 in a plan view. In addition to punching, the second through hole 46 can also be formed by using, for example, a drill or a laser. A light reflective sheet having the second through hole 46 may be purchased.
Next, as shown in FIGS. 15B and 15C, the second light-reflecting sheet 45 is overlapped and fixed on the support plate P to be removed later, and the light source 20 is arranged in the second through hole 46.

Subsequently, as in the first embodiment, as shown in FIGS. 15D to 15G, the light reflecting member 70A, the light guide member 10, and the light adjusting member 60 are formed. Then, the support plate P is removed. At this stage, the aggregate 152 of the light emitting modules 102 before the individualization is formed.
Similar to the first embodiment, the position where the light source 20 is arranged becomes the light source arrangement portion 11 in the light guide member 10 as a result. Further, since the lower surface of the light source 20 is not covered with the light guide member 10, the electrode 21 is exposed from the light guide member 10.
Then, as in the first embodiment, as shown in FIG. 15H, the aggregate 152 of the light emitting module 102 is cut by the grid line 70B of the light reflecting member 70A and separated into individual pieces.

(Wiring board preparation process)
The wiring board preparation step S2A is a step of preparing the first light reflective sheet 40 and the wiring board 30 for adhering the light emitting module 102. The first through hole 41 of the first light reflective sheet 40 is arranged so that one first through hole 41 faces one electrode 21 of the light source 20. The first light reflective sheet 40 is arranged on the wiring board 30 at a position where the wiring layer 32 and the first through hole 41 face each other. Here, the wiring board 30 forms a third through hole 31 that communicates with each of the first through holes 41 and penetrates the wiring layer 32.
In the wiring board preparation step S2A, it is preferable that the first through hole 41 of the first light reflective sheet 40 and the third through hole 31 of the wiring board 30 are formed at the same time. That is, the first light-reflecting sheet 40A before forming the first through hole 41 is attached to the bonded substrate 90A in which the light emitting module 102 of the wiring board 30A before forming the third through hole 31 is bonded to the surface to be bonded. By forming one through hole facing the electrode 21 in each of the positive and negative pairs of the light source 20, the first through hole 41 and the third through hole 31 are continuously formed. Is preferable.

First, as in the first embodiment, as shown in FIG. 16A, the wiring board 30A before forming the third through hole 31 is formed. Next, as shown in FIG. 16B, the bonded substrate 90A in which the first light reflective sheet 40A before forming the first through hole 41 is bonded to the surface of the wiring board 30A on the side where the light emitting module 102 is bonded. To form. Then, as shown in FIG. 16C, one through hole facing the electrode 21 of the light source 20 is formed on the bonded substrate 90A for each electrode 21. By forming the first through hole 41 and the third through hole 31 at the same time in this way, the accuracy of alignment between the first light reflective sheet 40 and the wiring board 30 can be improved.

(Light emitting module bonding process)
The light emitting module bonding step S3A is a step of bonding the wiring board 30 and the light emitting module 102.
In the light emitting module bonding step S3A of the third embodiment, the light emitting module 102 is bonded to the wiring board 30 by interposing the first light reflective sheet 40 so that the electrode 21 faces the first through hole 41. An adhesive resin is applied to the first light-reflecting sheet 40, and as shown in FIG. 17A, the electrode 21 and the first through hole 41 are aligned so as to face each other, and the light emitting module 102 is adhered. The adhesive resin is not shown. If the first light-reflecting sheet 40 has adhesiveness such as an adhesive sheet, the application of the adhesive resin can be omitted.

In the wiring substrate 30 after the light emitting module 102 is adhered, the third through hole 31 communicates with the first through hole 41 of the first light reflective sheet 40 when viewed from the surface on the side where the light emitting module 102 is not adhered. The tip of the through hole 41 is closed by the electrode 21 of the light source 20. That is, as many holes as the number of electrodes 21 are formed with the electrode 21 as the bottom and the third through hole 31 as the inlet. The region 25 between the pair of positive and negative electrodes 21 on the surface of the light source 20 having the electrodes 21 faces the first light reflective sheet 40.

(Connecting process and protective member forming process)
As shown in FIG. 17B, the connection step S4 is performed in the same manner as in the first embodiment. Further, by subsequently performing the protective member forming step S5, as shown in FIG. 17C, for example, the conductive member 50 and the exposed wiring layer 32 are covered, and further, the covering layer 36 around the opening 37 is also covered. The protective member 80 can be formed as described above.

(Modification example of light source)
The light source is not limited to the configuration of the light source 20 already shown. For example, a light source having a pair of positive and negative electrodes 21 on one side and having a blue or white emission color can be used. Here, a modification of the light source 20 will be described with reference to FIGS. 18A to 18D.
As shown in FIG. 18A, the light source 20A includes a light emitting element 22 that emits blue light and a translucent member 23A. The translucent member 23A contains a phosphor that emits yellow light, and the emission color of the light source 20A can be white. Further, the light source 20A is provided with the first light adjusting member 24A on the upper surface and the light reflecting layer 24B on the lower surface which is the surface having the electrodes 21. The light source 20A can reduce the amount of light reaching the wiring layer 32 by providing the light reflecting layer 24B on the surface having the electrodes 21.

As shown in FIG. 18B, the light source 20B includes a light emitting element 22 that emits blue light and a translucent member 23A, and can make the light emitting color white. Further, the light source 20B is provided with a first light adjusting member 24A on the upper surface thereof.
The translucent member 23A of the light source 20B is arranged on the light emitting element 22. The side surface and the lower surface of the semiconductor laminate of the light emitting element 22 and the lower surface of the translucent member 23A are each covered with the covering member 26. The covering member 26 is a member that covers and protects the light emitting element 22 and reflects the light from the light emitting element 22 toward the translucent member 23A. Examples of the material used for the covering member 26 include silicone resin, epoxy resin, and acrylic resin. The coating member 26 contains a light diffusing material such as titania, barium titanate, aluminum oxide, and silicon oxide.

The translucent member 23A of the light sources 20A and 20B may be a translucent member 23B that does not contain a phosphor. Further, the translucent members 23A and 23B can include a light diffusing material. Examples of the material used for the light diffusing material include titania, barium titanate, aluminum oxide, silicon oxide and the like.
The light sources 20A and 20B may be provided with a light reflecting layer 24B on the lower surface side of the light emitting element 22 and may not be provided with the first light adjusting member 24A, or may be provided with neither the first light adjusting member 24A nor the light reflecting layer 24B. It may be.

Further, as shown in FIGS. 18C and 18D, as a modification of the light source 20, light sources 20C and 20D in which the light emitting element 22 is not sealed in the translucent member 23A and the covering member 26 can also be used. In the light source 20C, the first light adjusting member 24C is arranged on the upper surface of the light emitting element 22. Further, in the light source 20D, the light reflection layer 24D is further arranged on the surface of the light source 20C having the electrode 21.
As the material used for the first light adjusting members 24A and 24C, for example, a resin material containing a light diffusing material, a metal material, or the like can be used as in the first embodiment. Further, as the first light adjusting members 24A and 24C, a dielectric multilayer film may be used, or a film obtained by laminating a dielectric multilayer film and a metal film may be used.

(Modification example of the method of forming the light guide member)
In the manufacturing method of the first embodiment, the light guide member 10 is formed by curing a liquid resin, but a light guide member (hereinafter referred to as a light guide plate) formed in advance may be used. .. The liquid referred to here also includes a paste. Further, although the description will be given here as a modified example of the first embodiment, it can be similarly applied to other embodiments.
As shown in FIG. 19A, the light guide plate 15a has a concave light source arrangement portion 11 having a size surrounding the light source 20 and covers the light source 20 so that the electrodes 21 are exposed. The light source 20 is arranged in the light source arrangement portion 11 via a translucent adhesive.

Further, as shown in FIG. 19B, the light source arrangement portion 11 may be a through hole. After arranging the light source 20 in the through hole of the light guide plate 15a1, a liquid resin may be injected and cured so as to cover the upper surface of the light source 20 to form the light guide member 15b. In this example, the light guide member composed of the light guide plate 15a1 and the light guide member 15b covers the light source 20 so that the electrodes 21 are exposed. The resin material of the light guide plate 15a1 and the resin material of the light guide member 15b may be the same or different. Further, the light guide plate 15a1 may be a single layer or a plurality of layers. For example, when the light guide plate 15a1 is composed of a plurality of layers, each layer may be laminated with an adhesive sheet. The material of such an adhesive sheet may be any material that is transparent to the light emitted from the light source 20, and is the same material as the light guide plate 15a1 so as to reduce the occurrence of an interface between layers. It is preferable to use it.

Further, as shown in FIG. 19C, a light guide member 15c including the first light guide plate 15c1 and the second light guide plate 15c2 may be used. The first light guide plate 15c1 has a through hole in which the light source 20 is arranged. The thickness of the first light guide plate 15c1 is substantially the same as the thickness of the light source 20. The second light guide plate 15c2 is arranged over the upper surface of the light source 20 and the upper surface of the first light guide plate 15c1. In this example, the recess formed by combining the first light guide plate 15c1 and the second light guide plate 15c2 serves as the light source arrangement portion 11, and the light source member 15c covers the light source 20 so that the electrodes 21 are exposed. .. The resin materials of the first light guide plate 15c1 and the second light guide plate 15c2 may be the same or different.

When the light guide plate is used, as shown in FIGS. 20C and 20D, the light reflection member 75A is arranged after the light guide plate 15a1 is arranged on the first light reflective sheet 40. In this case, a part of the light emitting module preparation process is changed. As an example, the light emitting module preparation step S1B when the light guide plate 15a1 is used will be described with reference to FIGS. 20A to 20F.
Similar to the light source preparation step S1 in the first embodiment, the first through hole 41 and the electrode 21 are aligned with each other so as to face the first light reflective sheet 40 in which the first through hole 41 is formed. The light source 20 is arranged.
Subsequently, the light guide plates 15a1 are arranged on the first light reflective sheet 40 so as to be adjacent to each other so that the light source 20 is housed in the light source arrangement portion 11. Then, the resin used as the material of the light guide member 15b is injected into the light source arranging portion 11 in the through hole so as to cover the light source 20 and cured. The light guide member composed of the light guide plate 15a1 and the light guide member 15b covers the light source 20 so that the electrodes 21 are exposed.
Subsequently, the material of the light reflecting member 75A is injected into the gap between the adjacent light guide plates 15a1 and cured. Then, as in the first embodiment, the light adjusting member (second light adjusting member) 60 is arranged on the light guide plate 15a1 and the light guide member 15b. Then, the aggregate 155 of the light emitting module 105 is cut by the grid line 75B of the light reflecting member 75A to be individualized. Although the second light adjusting member 60 in the present embodiment covers the entire upper surface of the light guide member 15b, a part of the upper surface of the light guide member 15b may be exposed from the second light adjusting member 60. ..
When the light reflecting member 75A is formed by a method of applying or injecting resin into the gap between the light guide members and curing the light reflecting member 75A in this way, the light reflecting member 75A is formed along the shape of the outer surface of the light guide member. NS. Therefore, by adjusting the shape of the outer surface of the light guide member in advance, the shape of the inner surface of the light reflecting member 75 can be adjusted.

Further, as another modification of the first embodiment, air may be used as the light guide member.

(Modification example of wiring board)
Next, a modified example of the wiring board will be described with reference to FIG. In this modification, the wiring board 30B does not have the third through hole 31. Therefore, it is configured as follows. Contact points for electrical connection between the conductive member 50 and the wiring layer 32 are provided at portions facing each of the first through holes 41 on the surface of the wiring layer 32 on the light reflective sheet 40 side.

The insulating base material 34B has openings facing each of the first through holes 41 of the light reflective sheet 40, and exposes the wiring layer 32B. The wiring layer 32B is thicker than the other portions in the thickness direction of the wiring board 30B at the portions facing each of the first through holes 41. Further, in this modification, the surface of the wiring layer 32B and the surface of the insulating base material 34B are substantially flush with each other. A conductive member 50 is arranged between the wiring layer 32B and the electrode 21 via the first through hole 41. The wiring layer 32B of the portion facing each of the first through holes 41 may protrude from the surface of the insulating base material 34B, or may be lower than the surface of the insulating base material 34B. The difference in the thickness of the wiring layer 32B can be adjusted by the thickness of the conductive member 50.
In the method of manufacturing a planar light source using the wiring board 30B having no third through hole 31, for example, in the light emitting module bonding step, the conductive member 50 is arranged on the wiring layer 32B before the light emitting module is bonded. That is, the conductive member 50 is arranged on the upper surface of the wiring layer 32B, and the light emitting module is adhered. At this time, the conductive member 50 is connected to the electrode 21 of the light source 20 via the first through hole 41. Further, the contact points between the conductive member 50 and the wiring layer 32B are arranged at portions facing each of the first through holes 41 on the surface of the wiring layer 32B on the side of the first light reflective sheet 40.

The wiring board 30B does not need to form an opening 37 in the coating layer 36B. Therefore, it is not necessary to arrange the protective member 80 that covers the opening 37 of the coating layer 36, and the number of steps in the manufacturing method can be reduced.
The modified example of the wiring board can be similarly applied to the first embodiment and other embodiments. For example, the conductive member 50 may be arranged in advance in the first through hole 41 of the light emitting module 101 as in the light emitting module 101 of the second embodiment. In this case, the conductive member 50 is joined to the electrode 21 of the light source 20 and the wiring layer 32B by using solder or the like. The wiring layer may be a plurality of layers instead of one layer. The embodiment in which the wiring board has the third through hole 31 and the modified example in which the wiring board does not have the third through hole 31 can be similarly carried out when the wiring layers are multi-layered.

10 Light guide member 11 Light source arrangement part of the light guide member 15a Light source plate 20 Light source 21 A pair of positive and negative electrodes of the light source 22 Light emitting element of the light source 23 Translucent member of the light source 24A Light adjustment member of the light source (first light adjustment member)
25 Area between the electrodes on the surface having the electrodes of the light source 26 Coating member of the light source 30 Wiring board 31 Third through hole 32 Wiring layer of the wiring board 34 Insulating base material of the wiring board 36 Coating layer of the wiring board 40 Light reflective sheet , 1st light reflective sheet 41 1st through hole 45 2nd light reflective sheet 46 2nd through hole 50 Conductive member 51 1st conductive member 52 2nd conductive member 60 Light adjustment member (2nd light adjustment member)
70 Light-reflecting member 75 Modification example of light-reflecting member 80 Protective member 90 Laminated board 100 Light-emitting module 150 Assembly of light-emitting module 200A Part of planar light source 200, 300 Planar light source

Claims (21)

A light source having a pair of positive and negative electrodes on one side,
A light guide member that covers the light source so that the electrodes are exposed,
A wiring board having a wiring layer to which the electrodes are electrically connected,
A light-reflecting sheet having a first through hole that is interposed between the light guide member and the wiring board and faces each of the positive and negative electrodes, one by one, is provided.
A planar light source in which the electrodes and the wiring layer are electrically connected by a conductive member arranged through the first through hole. The light-reflecting sheet includes a first light-reflecting sheet having the first through hole and a second light-reflecting sheet having a second through hole facing the first through hole and in which the light source is arranged. The planar light source according to claim 1. The first or second aspect of the present invention, wherein the contact point between the conductive member and the wiring layer is arranged at a portion of the wiring layer on the surface of the wiring layer on the light reflective sheet side facing each of the first through holes. Planar light source. The wiring board has a third through hole that communicates with each of the first through holes and penetrates the wiring layer, and the contact point between the conductive member and the wiring layer is at least inside the third through hole. The planar light source according to claim 1 or 2, which is arranged in. The planar light source according to claim 4, wherein the contact point between the conductive member and the wiring layer is further arranged on a surface of the wiring layer opposite to the surface of the wiring layer on the light reflective sheet side. Claims 1 to 5 include a first conductive member arranged in the first through hole and a second conductive member arranged between the first conductive member and the wiring layer. The planar light source according to any one of the above. The planar light source according to any one of claims 1 to 6, further comprising a light adjusting member arranged on the light guide member so as to face the light source via the light guide member. The planar light source according to any one of claims 1 to 7, further comprising a light reflecting member surrounding the light source. The planar light source according to any one of claims 1 to 8, wherein the region between the pair of positive and negative electrodes on the surface having the electrodes of the light source faces the light reflective sheet. The planar light source according to any one of claims 1 to 9, wherein a plurality of the light sources are arranged on the wiring board. A first having a light source having a pair of positive and negative electrodes on one side, a light guide member covering the light source so that the electrodes are exposed, and a first through hole facing each of the positive and negative electrodes. A light source module preparation process for preparing a light source module including a light reflective sheet, and
A wiring board preparation step of preparing a wiring board having a wiring layer to which the electrodes are electrically connected, and
A light emitting module bonding step of bonding the light emitting module to the wiring board,
A method for manufacturing a planar light source, which includes a connection step of electrically connecting the electrode and the wiring layer via a conductive member arranged in the first through hole. The surface according to claim 11, wherein in the connection step, the electrode and the wiring layer are electrically connected by using the conductive member previously arranged in the first through hole of the first light reflective sheet. A method for manufacturing a light source. A first through hole having a pair of positive and negative electrodes facing each of the positive and negative electrodes on a wiring substrate having a wiring layer to which the electrodes of a light source having a pair of positive and negative electrodes are electrically connected is provided. 1 A wiring substrate preparation step in which the light reflective sheet is arranged so that the wiring layer and the first through hole face each other.
A light source, a second light-reflecting sheet facing the first through hole and having a second through hole in which the light source is arranged, and a light guide member covering the light source so that the electrode is exposed. A light emitting module preparation step of arranging the light source in the second through hole and preparing a light emitting module in which the light source is arranged in the light guide member.
A light emitting module bonding step of bonding the light emitting module to the wiring board by interposing the first light reflective sheet so that the electrode faces the first through hole.
A method for manufacturing a planar light source, which includes a connection step of electrically connecting the electrode and the wiring layer via a conductive member arranged in the first through hole. In the connection step, the contact point between the conductive member and the wiring layer is arranged in a portion of the wiring layer on the surface of the wiring layer on the side of the first light-reflecting sheet facing each of the first through holes. The method for manufacturing a planar light source according to any one of claims 13. In the wiring board preparation step, a third through hole that communicates with each of the first through holes and penetrates the wiring layer is formed in the wiring board.
The method for manufacturing a planar light source according to any one of claims 11 to 13, wherein the connection step is such that the contact point between the conductive member and the wiring layer is arranged at least inside the third through hole. In the wiring board preparation step, a positive and negative pair is formed on the bonded substrate in which the first light reflective sheet before the formation of the first through hole is bonded to the surface of the wiring board on the side to which the light emitting module is bonded. By forming through holes facing the electrodes one by one, the formation of the first through hole and the formation of the third through hole that communicates with each of the first through holes and penetrates the wiring layer. In succession,
The method for manufacturing a planar light source according to claim 13, wherein the connection step is such that the contact point between the conductive member and the wiring layer is arranged at least inside the third through hole. The connection step according to claim 15 or 16, wherein the contact point between the conductive member and the wiring layer is arranged on a surface of the wiring layer opposite to the surface of the wiring layer on the first light reflective sheet side. A method for manufacturing a planar light source. The planar light source according to any one of claims 11 to 17, wherein in the light emitting module preparation step, a light adjusting member is arranged on the light guide member so as to face the light source via the light guide member. Manufacturing method. The method for manufacturing a planar light source according to any one of claims 11 to 18, wherein the light emitting module preparation step further arranges a light reflecting member surrounding the light source. The method for manufacturing a planar light source according to any one of claims 11 to 19, wherein a region between a pair of positive and negative electrodes on the surface having electrodes of the light source is made to face the first light reflective sheet. .. The method for manufacturing a planar light source according to any one of claims 11 to 20, wherein the light emitting module bonding step is a method of arranging a plurality of the light emitting modules on the wiring board.

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