JP7140999B2 - Planar light source and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a planar light source and a manufacturing method thereof.

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

JP 2019-003994 A

An object of the present disclosure is to provide a planar light source that suppresses the absorption of light from the light source by wiring materials, and a manufacturing method thereof.

A planar light source according to the present disclosure includes 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 wiring layer electrically connected to the electrodes. a wiring board; and a light reflective sheet interposed between the light guide member and the wiring board and having a first through hole facing each of the electrodes forming a pair of positive and negative electrodes; and the wiring layer are electrically connected by a conductive member disposed through the first through hole.

A 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 covering the light source so that the electrodes are exposed; a light-emitting module preparing step of preparing a light-emitting module comprising a first light reflective sheet having first through holes facing each other; and a wiring board of preparing a wiring board having a wiring layer to which the electrodes are electrically connected. a preparation step; a light-emitting module bonding step of bonding the light-emitting module to the wiring board; and a connecting step of electrically connecting the electrode and the wiring layer via a conductive member disposed in the first through hole. including.

Further, in the method for manufacturing a planar light source according to the present disclosure, a pair of positive and negative electrodes are formed on a wiring board having a wiring layer to which the electrodes of the light source having a pair of positive and negative electrodes are electrically connected on one surface side. a wiring board preparing step of arranging a first light reflective sheet having first through holes facing electrodes one by one so that the wiring layer and the first through holes face each other; the light source; a second light reflective sheet facing the 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 as to expose the electrode, wherein the second through hole a light-emitting module preparing step of preparing a light-emitting module in which the light source is arranged in the light guide member and 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 with a sheet interposed therebetween; and electrically connecting the electrode and the wiring layer via a conductive member arranged in the first through hole. and a connecting step.

ADVANTAGE OF THE INVENTION According to this indication, the planar light source which can suppress the absorption of the light by a wiring material and can use the light which a light source emits more effectively, and its manufacturing method are realizable.

1 is a schematic perspective view showing a planar light source according to a first embodiment; FIG. FIG. 2 is a schematic cross-sectional view taken along line II-II shown in FIG. 1; 1 is a schematic perspective view showing an example of a light source according to a first embodiment; FIG. 3B is a schematic cross-sectional view taken along line IIIB-IIIB shown in FIG. 3A; FIG. 3B is a schematic bottom view showing a surface having electrodes of the light source shown in FIG. 3A; FIG. FIG. 4 is a schematic plan view showing openings in a covering layer in the wiring board according to the first embodiment; 1 is a schematic perspective view showing a light emitting module according to a first embodiment; FIG. It is a schematic plan view showing the positional relationship between the light source and the light reflecting member according to the first embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 1st Embodiment. It is a schematic sectional drawing which shows some planar light sources based on 2nd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows some planar light sources based on 3rd Embodiment. FIG. 11 is a schematic perspective view showing a light emitting module according to a third embodiment; It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows an example of the manufacturing method which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the modification of a light source. It is a schematic sectional drawing which shows the modification of a light source. It is a schematic sectional drawing which shows the modification of a light source. It is a schematic sectional drawing which shows the modification of a light source. It is a schematic perspective view which shows the modification of a light guide member. It is a schematic sectional drawing which shows the modification of a light guide member. It is a schematic sectional drawing which shows the modification of a light guide member. It is a schematic sectional drawing which shows an example of the manufacturing method based on the modification of a light guide member. It is a schematic sectional drawing which shows an example of the manufacturing method based on the modification of a light guide member. It is a schematic sectional drawing which shows an example of the manufacturing method based on the modification of a light guide member. It is a schematic sectional drawing which shows an example of the manufacturing method based on the modification of a light guide member. It is a schematic sectional drawing which shows an example of the manufacturing method based on the modification of a light guide member. It is a schematic sectional drawing which shows an example of the manufacturing method based on the modification of a light guide member. It is a schematic sectional drawing which shows the planar light source provided with the wiring board which concerns on the modification of this embodiment. It is a flow chart which shows a manufacturing method of a plane light source concerning this embodiment.

A planar light source and a manufacturing method thereof according to embodiments will be described below with reference to the drawings. It should be noted that the drawings referred to in the following description of the embodiments are schematic representations of the embodiments. Alternatively, an end view showing only a cut surface may be used as a cross-sectional view. In addition, in the following description, the same names and symbols basically indicate the same or homogeneous members, and detailed description thereof will be omitted as appropriate. In this specification, terms such as "upper" and "lower" indicate relative positions between constituent elements in the drawings referred to for explanation, and indicate absolute positions unless otherwise specified. not intended.

[First embodiment]
(planar 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. FIG. A planar light source 200 whose cross section is shown in FIG. The planar light source 200 and the planar light source 300 differ in the number of light emitting modules described later, and each light emitting module has the same configuration.
The planar light source 300 includes a light source 20 having a pair of positive and negative electrodes 21 on one side, a light guide member 10 covering the light source 20 so that the electrodes 21 are exposed, and a wiring layer 32 electrically connected to the electrodes 21. and a light reflecting sheet 40 interposed between the light guide member 10 and the wiring board 30 . The light reflective sheet 40 has a first through hole 41 facing the electrode 21, one for each of the positive and negative electrodes 21 of the light source 20, that is, one for each electrode 21, and the electrode 21 and the wiring layer. 32 are electrically connected by a conductive member 50 arranged through the first through hole 41 .
Each configuration of the planar light source 300 will be described below. The light extraction surface of planar light source 300 is the upper surface of light guide member 10 located on the opposite side of light reflecting sheet 40 . In addition, in this embodiment, the light adjustment 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 side, and emits light when a voltage is applied from the outside through the electrodes 21 . The light source 20, as shown in FIGS. 3A to 3C, 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 includes a pair of positive and negative electrodes 21 so as to be exposed on the lower surface of the translucent member 23A opposite to the upper surface on which the first light adjusting member 24A is arranged.

The light-emitting element 22 includes a semiconductor laminate, and in this embodiment, at least the upper surface and side surfaces of the semiconductor laminate are surrounded by the translucent member 23A. The semiconductor laminate is configured to emit visible light or ultraviolet light, and any composition can be used according to the desired emission peak wavelength. For example, a nitride semiconductor (In _x Al _y Ga _1-x-y 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 can be used. Also, the size and number 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, a p-type semiconductor layer, and a light-emitting layer sandwiched therebetween. The light-emitting layer may have a structure such as a double heterojunction or a single quantum well (SQW), or may have a structure with 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. You may have a structure in which a structure containing and in order is repeated multiple times. When the semiconductor laminate includes a plurality of light-emitting layers, it may include light-emitting layers with different emission peak wavelengths, or may include light-emitting layers with the same emission peak wavelength. In addition, the same emission peak wavelength includes the case where there is a variation of about several nanometers. A combination of emission peak wavelengths between a plurality of light-emitting layers can be selected as appropriate. 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 , a combination of green light and red light, etc., to select the light-emitting layer. Each light-emitting layer may include a plurality of active layers with different emission peak wavelengths, or may include a plurality of active layers with the same emission peak wavelength.

The translucent member 23A is made of, for example, a translucent resin material such as an epoxy resin, a silicone resin, or a resin mixture thereof. The translucent member 23A may contain a phosphor. For example, by containing a phosphor that absorbs blue light from the light-emitting element 22 and emits yellow light, the light-transmitting member 23A emits white light from the light source 20. can be emitted. Further, the translucent member 23A may contain 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 a phosphor that emits red light. White light can also be emitted from the light source 20 by including the radiating phosphor. Such phosphors include, for example, yttrium-aluminum-garnet-based phosphors (eg, Y ₃ (Al, Ga) ₅ O ₁₂ :Ce), lutetium-aluminum-garnet-based phosphors (eg, Lu ₃ (Al , Ga) ₅ O ₁₂ :Ce), terbium aluminum garnet-based phosphors (e.g., Tb ₃ (Al, Ga) ₅ O ₁₂ :Ce), CCA-based phosphors (e.g., Ca ₁₀ (PO ₄ ) ₆ C _l2 :Eu), SAE phosphors (e.g., _Sr4Al14O25 :Eu), _{chlorosilicate} phosphors ₍ e.g., _{Ca8MgSi4O16Cl2} : _Eu ), β _{- sialon} phosphors (e.g., (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 a lanthanide element excluding Li, Mg, Ca, Y, and La and Ce)), an SLA phosphor (e.g. SrLiAl ₃ N ₄ :Eu), a CASN phosphor (e.g. CaAlSiN ₃ :Eu) or SCASN Nitride-based phosphors (e.g., (Sr, Ca)AlSiN ₃ :Eu), KSF-based phosphors (e.g., K ₂ SiF ₆ :Mn), KSAF-based phosphors (e.g., K ₂ (Si , Al)F6:Mn) or MGF _- based phosphors (e.g., _{3.5MgO.0.5MgF2.GeO2} :Mn) and other fluoride _- based phosphors, phosphors having a perovskite structure (e.g., CsPb(F , Cl, Br, I) ₃ ), or quantum dot phosphors (eg, CdSe, InP, AgInS ₂ or AgInSe ₂ ), or the like can be used.

Also, a wavelength conversion sheet containing the phosphor described above may be arranged on the planar light sources 200 and 300 . The wavelength conversion sheet can be used as a planar light source that absorbs part of the blue light from the light source 20, 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. Alternatively, a light source capable of emitting blue light may be combined with a wavelength conversion sheet containing a red phosphor and a green phosphor. Also, a light source capable of emitting blue light may be combined with a plurality of wavelength conversion sheets. 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. Also, 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. may

The first light adjustment member 24A is a member for adjusting the light distribution of the light source 20. As shown in FIG. The first light adjustment member 24</b>A blocks or reflects part of the light traveling from the inside of the light source 20 to the outside through the upper surface of the light source 20 . The light distribution of the light source 20 is adjusted via the first light adjustment member 24A so that the light emission from the light extraction surface of the planar light source 300 does not become too strong and the light emission from the entire surface is uniform. . When the transmittance of the first light adjustment member 24A with respect to the light emitted from the light emitting element 22 is sufficiently low, for example, 1% or more and 50% or less, preferably 3% or more and 30% or less, the first light adjustment member 24A It becomes a light-shielding film, and it is possible to avoid the luminance directly above the light source 20 from becoming too high. As the first light adjustment member 24A, for example, a resin material containing a light diffusion material may be used, or a metal material may be used. For example, as the resin material, a silicone resin, an epoxy resin, or a resin mixture thereof can be used. As the light diffusing material, for example, known materials such as titania, silica, alumina, zinc oxide and glass can be used. In addition, a multilayer film (dielectric multilayer film) made of dielectrics in which two or more kinds of dielectrics are laminated can be used for the first light adjusting member 24A.

(light guide member)
As shown in FIGS. 1 and 2, the light guide member 10 is a member having translucency for extracting the light from the light source 20 as planar light from the upper surface serving as the light extraction surface of the planar light source 300 . . The lower surface of the light guide member 10 is arranged to face the light reflecting sheet 40 except for the light source arrangement portion 11 where 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, etc., and effectively utilizes the light from 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 greater than the height of the light source 20, and may exceed the height of the light reflecting member 70 described later. It is preferable that the height of the light guide member 10 is, 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 electrode 21 is exposed. A concave portion 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 top surface and side surfaces of the light source 20 arranged in the light source arrangement portion 11 .

Examples of the material of the light guide member 10 include thermoplastic resins such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate and polyester, resin materials such as thermosetting resins such as epoxy resins and silicone resins, and translucent materials such as glass. A material having properties 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, for example, convex portions and/or concave portions in low-luminance regions in order to reduce luminance unevenness.

(light reflective sheet)
The light reflective 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 interposed between the light guide member 10 and the wiring board 30 to be 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 is large enough to contain the entire electrode 21 in 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 reflective sheet 40 facing the light source 20 becomes. Therefore, the area of the wiring layer 32 and the like irradiated with the light from the light source 20 through the first through hole 41 is increased. In addition, when the wiring layer 32 and the like are irradiated with light, the chances of the light being absorbed also increase. Therefore, the shape of the opening of the first through hole 41 should be substantially the same as the shape of the electrode 21 in plan view, or the opening of the first through hole 41 should be made smaller so that it is located inside the outer edge of the electrode 21 . is preferred. Also, the opening of the first through-hole 41 should not protrude outside the outer edge of the light source 20 in 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 plan view. Thereby, it is possible to reduce the absorption of the light from the light source 20 by the conductive member 50 arranged in the first through hole 41 .

The light reflective sheet 40 preferably has a high reflectance in order to effectively utilize light. The reflectance of the light reflective 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 .
For the light-reflective sheet 40, a resin sheet containing a large number of cells (for example, a foamed resin sheet), a resin sheet containing a light diffusing material, or the like can be used. Examples of resins used for these light reflective sheets 40 include thermoplastic resins such as acrylic resins, polycarbonate resins, cyclic polyolefin resins, polyethylene terephthalate resins, polyethylene naphthalate resins, polyester resins, epoxy resins, silicone resins, and the like. thermosetting resin can be used. As the light diffusing material, for example, known materials such as titania, silica, alumina, zinc oxide and 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 adjustment 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 uniformity. The transmittance of the second light adjusting member 60 is preferably, for example, 20% or more and 60% or less, more preferably 30% or more and 40% or less, with respect to the light from the light source 20 . As with the first light adjustment member 24A, for the second light adjustment member 60, for example, a light-reflecting material such as a resin material containing a light diffusion material or a metal material can be used. The second light adjustment member 60 in this embodiment covers the entire light source 20 in plan view and has a circular outer edge, but may have a rectangular shape. Moreover, although the second light adjustment member 60 is film-shaped in the present embodiment, it may be dot-shaped.

(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 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 extracts the light. The light reflecting member 70 has a predetermined height and is arranged along the outer periphery of the light guide member 10 on the light reflecting sheet 40 . By partitioning the light guide member 10 by the light source 20 with the light reflecting member 70, it is possible to suppress light guiding between adjacent partitions. This enables local dimming that controls the light emitting area in units of sections.
The height of the light reflecting member 70 in the direction perpendicular to the light reflecting sheet 40 is preferably equal to or greater than the height of the light source 20 . In plan view, the length of one side of the rectangular frame-shaped light reflecting member 70 is longer than the length of one side of the light source 20, for example, in the range of 5 to 30 times.

The inner surface of the light reflecting member 70 is curved convexly toward the light source 20 in this embodiment, but may be curved concavely. In particular, it is preferable that the cross-sectional shape of the light reflecting member 70 becomes narrower with increasing distance from the light reflecting sheet 40 in the height direction. You can take it out efficiently. 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, or a combination of a plurality of curved surfaces having different curvatures. and a curved surface.
The reflectance of the light reflecting member 70 with respect to the light from the light source 20 is, for example, preferably 60% or more, more preferably 90% or more. For 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, thermoplastic resin such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin or polyester resin, or thermosetting resin such as epoxy resin or silicone resin may be used. can. 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 electrically connected to the pair of positive and negative electrodes 21 , and a covering layer 36 covering the wiring layer 32 . The wiring board 30 has third through holes 31 that penetrate the wiring layer 32 in communication with the first through holes 41 .
A rigid substrate or a flexible substrate, for example, can be used for the wiring substrate 30 .
The surface of the wiring board 30 on which the light source 20 is not arranged is defined as a first surface, and the surface opposite to the first surface is defined as a second surface.

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

A 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 phenol resin, epoxy resin, polyimide resin, BT resin, or polyphthalamide. A ceramic material such as alumina or aluminum nitride may be used for the insulating base material 34 . Further, the insulating base material 34 may be formed by arranging an insulating member in layers on the surface of a metal member.

The covering layer 36 is a member that protects the wiring layer 32 . The covering layer 36 may be arranged to cover the entire insulating base material 34 . In the first embodiment, the covering layer 36 has openings 37 to expose the third through holes 31 and the wiring layer 32 disposed therearound, as shown in FIG. 4, for example. As the material of the coating layer 36, an insulating material such as polyimide is used.

(Conductive member)
The conductive member 50 is a member that electrically connects the electrode 21 and the wiring layer 32 .
As described above, the first through holes 41 are arranged in the light reflective sheet 40 so as to face the respective pairs of positive and negative electrodes 21 of the light source 20 , and the wiring board 30 is provided with the first through holes 41 . A third through hole 31 is arranged to communicate with each. In other words, there is a path between the electrode 21 and the wiring layer 32 that allows one of the electrodes 21 and one of the third through holes 31 to correspond one-to-one. A conductive member 50 is arranged in each of these paths to electrically connect the electrode 21 and the wiring layer 32 .
As the material of the conductive member 50, in addition to the material similar to that of 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 contact between the wiring layer 32 and the conductive member 50 is arranged inside the third through hole 31 and on the surface of the wiring layer 32 opposite to the surface facing the light reflecting sheet 40. be done. Here, the surface of the wiring layer 32 opposite to the surface facing the light reflective 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. is placed in 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 side surface of the third through-hole 31 (the inner side surface of the through-hole of the wiring layer 32) and the periphery of the third through-hole 31. Arranged in the wiring layer 32, electrical connection can be ensured. Further, the inner side surface of the third through hole 31 in this 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, 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 in plan view. Furthermore, the wiring layer 32 may be arranged so as to surround the entire periphery 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 so as to surround the entire periphery of the through-hole of the insulating base material 34 . It may be arranged in part.

(Protection member)
In addition to the configuration described above, the planar light source 300 may include a protective member 80 that covers the opening 37 of the covering layer 36 of the wiring board 30 . The protective member 80 is a member that has insulating properties and protects the wiring layer 32 and the conductive member 50 from being short-circuited.
Phenyl silicone resin, dimethyl silicone resin, epoxy resin, acrylic resin, urethane resin, or the like can be used for the protective member 80 . In addition, the protective member 80 may be translucent, or may be opaque by adding a pigment such as titanium oxide. In particular, it is preferable that the protective member 80 has translucency, because 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, through the first through holes 41 arranged in the light reflective sheet 40 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 except for the electrode 21 faces the light reflective sheet 40, and the light from the light source 20 can be used effectively. In addition, since the pair of positive and negative electrodes 21 are arranged separately, the pair of positive and negative electrodes of one light source 20 can be formed on the lower surface of the light source 20 as shown in FIG. There is a region 25 between 21 . Since this area 25 also faces the light reflecting sheet 40, the light from the light source 20 can be used more effectively. In this manner, the planar light source 300 can increase the area of the light reflecting sheet 40 facing the light source 20 and reduce the area of the wiring layer 32 and the like irradiated with light. Therefore, the planar light source 300 can effectively use the light from the light source 20 by suppressing the absorption of light by the wiring layer 32 and the like.

One or more light sources 20 may be arranged on the wiring board 30 . The number of light sources 20 can be appropriately selected according to the size and shape of the planar light source 300 . Also, the interval 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 a 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. FIG.
The manufacturing method of the planar light source 300 comprises: a light source 20 having a pair of positive and negative electrodes 21 on one side; a light guide member 10 covering the light source 20 so that the electrodes 21 are exposed; a light-emitting module preparation step S1 for preparing a light-emitting module 100 including a first light reflective sheet 40 having first through holes 41 facing each of the electrodes 21; a wiring board preparation step S2 of preparing a wiring board 30 having a wiring board 30; a light emitting module bonding process S3 of bonding a light emitting module 100 to the wiring board 30; a connecting step S4 for electrically connecting the layer 32; 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 the light-emitting module 100 including at least the light source 20, the light guide member 10, and the first light reflecting sheet 40. FIG. The planar light source 300 is constructed by combining the light-emitting module 100 as shown in FIG. In addition, 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 .
Also, here, a case will be described in which a plurality of light emitting modules 100 are formed by forming an assembly of light emitting modules 100 and then singulating the assembly. Here, singulation includes the case of cutting so as to have one light source 20 as well as the case of cutting so as to have two or more light sources 20 . Then, the cut light emitting modules can be respectively bonded to the wiring substrate 30 in the light emitting module bonding step described later.

First, as shown in FIG. 7A, a light reflective sheet is provided with first through holes 41 such that one first through hole 41 corresponds to one electrode 21 of the light source 20, and a first light reflective sheet is formed. form 40; That is, in this example, two first through holes 41 are provided for one light source 20 . The formation of the first through holes 41 can be performed by punching, for example, using a punch that substantially matches the shape of the electrode 21 in plan view. The formation of the first through-holes 41 can be performed by using, for example, a drill or a laser instead of punching. Alternatively, a light reflective sheet having first through holes 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. A 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 reflecting sheet 40 .

Subsequently, as shown in FIG. 7C, a light reflecting member 70A is arranged so as to surround the light source 20 with a certain distance therebetween. As shown in FIG. 6, the light reflecting member 70A has a lattice shape in plan view. Each grating of the light reflecting member 70A is arranged so as to surround one light source 20 at the center. The light reflecting member 70A can be formed, for example, by coating the first light reflecting sheet 40 with the material of the light reflecting member 70A in a state of having an appropriate viscosity. The cross section of the light reflecting member 70A has, for example, a shape obtained by cutting an ellipse in half along the minor axis, but it 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 and curing a resin that is the material of the light guide member 10 into a region surrounded by a frame formed by the light reflecting members 70A. The resin may be injected through a nozzle of a dispenser, applied by screen printing or spraying, or may be used in combination. In this manufacturing method, the position where the light source 20 is previously arranged becomes the light source arrangement portion 11 of the light guide member 10 as a result. 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 while 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 reflective sheet 40, so that the light from the light source 20 can be used effectively. The light guide member 10 can be prepared by injection molding or transfer molding, or may be prepared by purchasing a molded product.

Subsequently, as shown in FIG. 7E , the light adjustment member 60 is arranged on the light guide member 10 so as to face the light source 20 through the light guide member 10 . The light adjustment member 60 can be formed, for example, by coating the light guide member 10 with a resin that is the material of the light adjustment member 60 and curing the resin. At this stage, an assembly 150 of light emitting modules 100 before singulation is formed.
Then, as shown in FIG. 7F, the assembly 150 of the light emitting modules 100 is cut along the grid lines 70B of the light reflecting members 70A to separate them. Cutting can be performed by a known method using, for example, a dicing blade or laser. In this manner, 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 bonding the light emitting module 100 . Here, the wiring board 30 is provided with third through holes 31 that penetrate the wiring layer 32 and communicate with the first through holes 41 respectively. FIG. 8A shows a cross-sectional view of the wiring board 30A before the third through holes 31 are formed. FIG. 8B shows a cross-sectional view of the wiring substrate 30 after the third through holes 31 are formed.
First, the wiring layer 32A is arranged on the insulating base material 34A, and the covering layer 36 is arranged so as to cover the wiring layer 32A, thereby forming the wiring board 30A. In order to dispose the conductive member 50 in a later step, the covering layer 36 has, as shown in FIG. Keep
Next, the wiring substrate 30A before the formation of the third through holes 31 is provided with the third through holes 31 so as to communicate with the respective first through holes 41 of the first light reflective sheet 40 and pass through the wiring layer 32. Form. The third through hole 31 can be formed by punching, drilling, laser processing, or the like, for example. In addition, in the wiring board preparing step S2, the wiring board having the wiring layer and the covering layer formed as described above and having the third through holes 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 substrate 30 and the light-emitting module 100 together.
As shown in FIG. 9A, an adhesive resin is applied to the surface of the wiring substrate 30 to which the light emitting module 100 is to be adhered, and the positions are aligned so that the first through holes 41 and the third through holes 31 face each other. Glue 100. The illustration of the adhesive resin is omitted. 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. Note that in FIG. 9A, adjacent light emitting modules 100 are in close contact. However, the interval between the light emitting modules 100 may be, for example, about 1% to 10% of the width of the light emitting modules 100, and can be set as appropriate.

Wiring board 30 to which light-emitting modules 100 are adhered is viewed from the side to which light-emitting modules 100 are not adhered. The tip of the 1 through hole 41 is closed by the electrode 21 of the light source 20 . That is, the number of holes having the electrode 21 as the bottom and the third through hole 31 as the entrance is formed by the number of the electrodes 21 .

(Connection process)
The connection step S<b>4 is a step of electrically connecting the electrode 21 and the wiring layer 32 with 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 entrance. When the conductive member 50 is injected, the wiring substrate 30 with the light emitting module 100 adhered thereto is placed horizontally, with the light emitting module 100 side facing down. The amount of the conductive member 50 is required to sufficiently reach the electrode 21 which is the bottom of the hole and to ensure contact with the wiring layer 32 inside the third through hole 31 . The conductive member 50 is injected in such an amount that it also spreads over the surface of the wiring layer 32 outside the third through hole 31 . In other words, the contact for 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 of the wiring layer 32 facing the first light reflective sheet 40 . Electrical connection with the wiring layer 32 becomes more reliable.
After the injection of 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 applied before or after the conductive member 50 is heated. You may isolate|separate for every hole using. Also, the conductive member 50 may be injected from a nozzle of a dispenser, may be provided by screen printing, or may be a combination of nozzle injection and screen printing, such as screen printing after injection from a nozzle.

(Protection member forming step)
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 well.

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

[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.
A planar light source 201 differs from the planar light source 200 according to the first embodiment in the configuration of the conductive member. Other configurations are the same as those of the first embodiment. Note that descriptions of portions common to the first embodiment will be omitted as appropriate.

(First conductive member and second 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. Prepare. The electrode 21 and the wiring layer 32 are electrically connected 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. Alternatively, it may be arranged so as to protrude from the first through hole 41 . As materials for 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. The materials of the first conductive member 51 and the second conductive member 52 may be the same material or different materials.

The planar light source 201 faces the light reflecting sheet 40 over the entire lower surface of the light source 20 excluding the electrodes 21 , so that the light from the light source 20 can be used effectively. 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 . Also, for the first conductive member 51 , a material suitable for bonding with the electrode 21 can be selected.

(Manufacturing method of planar light source according to second embodiment)
An example of a method for manufacturing a planar light source according to the second embodiment will be described with reference to FIGS. 11A to 12B and FIG. The drawing shows an example in which a plurality of light emitting modules are combined with a wiring board.
The manufacturing method of the planar light source according to the second embodiment differs from the manufacturing method of the planar light source according to the already explained first embodiment in the light-emitting module preparation step S12 and the connecting 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 manufacturing method of the planar light source according to the second embodiment, the electrode 21 and the wiring layer 32 are connected via a conductive member pre-arranged in the first through hole 41 of the first light reflective sheet 40. Connect electrically. The conductive member pre-arranged 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. The first conductive member 51 is provided in the first through hole 41 of the first light reflecting sheet 40 before the light source 20 is arranged, as shown in FIGS. 11A and 11B. The first conductive member 51 and the electrode 21 of the light source 20 are joined using solder or the like. The step of providing the second conductive member 52 is performed after bonding the light emitting module 101 to the wiring board 30 as shown in FIGS. 12A and 12B. The light-emitting module preparing step S12 is the same as the light-emitting module preparing 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 a conductive member in advance in the first through hole 41, other steps can be carried out 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 differs from the planar light source 200 according to the first embodiment in the structure of the light reflecting sheet. Other configurations are the same as those of the first embodiment. Note that descriptions of portions common to the first embodiment will be omitted as appropriate.

(First Light Reflective Sheet and Second Light Reflective Sheet)
The light reflective sheet of the planar light source 202 has a first light reflective 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. and a second light reflective sheet 45 .
As with 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 from the light source 20. be able to. In the planar light source 202, the area 25 between the electrodes 21 of the light source 20 faces the first light reflective sheet 40, so that the area of the wiring layer 32 or the like irradiated with light can be reduced. . In the planar light source 202 , the first light reflective sheet 40 and the second light reflective sheet 45 are stacked around the light source 20 . By stacking the light-reflecting sheets, the planar light source 202 can further reduce light irradiation to the wiring layer 32 and the like.

(Manufacturing method of planar light source according to the third embodiment)
An example of a method for manufacturing a planar light source according to the third embodiment will be described with reference to FIGS. 14 to 17C and 22. FIG. The drawing shows an example in which a plurality of light emitting modules are combined with a wiring board.
In the manufacturing method of the planar light source according to the third embodiment, the light source 20 is formed on the wiring substrate 30 having the wiring layer 32 to which the electrode 21 of the light source 20 having a pair of positive and negative electrodes 21 on one surface side is electrically connected. A wiring board preparation step of arranging a first light reflective sheet 40 having first through holes 41 facing each pair of positive and negative electrodes 21 one by one so that the wiring layer 32 and the first through holes 41 face each other. S2A, the light source 20, a second light reflective sheet 45 facing the first through hole 41 and having a second through hole 46 in which the light source 20 is arranged, and covering the light source 20 so that the electrode 21 is exposed. a light-emitting module preparation step S1A for preparing a light-emitting module 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; a light emitting module bonding step S3A of bonding the light emitting module 102 to the wiring board 30 with the first light reflecting sheet 40 interposed so as to face the first through hole 41; and a connection step S4 of electrically connecting the electrode 21 and the wiring layer 32 via. 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 the light-emitting module 102 including at least the light source 20, the light guide member 10, and the second light reflective sheet 45. FIG. The planar light source 202 is configured by combining the light-emitting module 102 or a unit in which a plurality of light-emitting modules 102 are arranged as shown in FIG. 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 assembly of light emitting modules 102 and then singulating the assembly. In this case as well, singulation includes not only the case of cutting so as to have one light source 20 but also the case of cutting so as to have two or more light sources 20 . Then, the cut light emitting modules can be respectively bonded to the wiring substrate 30 in the light emitting module bonding step described later.

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

Subsequently, similarly to the first embodiment, as shown in FIGS. 15D to 15G, the light reflection member 70A, the light guide member 10, and the light adjustment member 60 are formed. Then, the support plate P is removed. At this stage, an assembly 152 of light emitting modules 102 before singulation is formed.
As in the first embodiment, the position where the light source 20 is arranged eventually becomes the light source arrangement portion 11 of the light guide member 10 . Moreover, since the lower surface of the light source 20 is not covered with the light guide member 10 , the electrodes 21 are exposed from the light guide member 10 .
Then, as in the first embodiment, as shown in FIG. 15H, the assembly 152 of the light emitting modules 102 is cut along the grid lines 70B of the light reflecting members 70A to separate them.

(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 bonding the light emitting module 102 . The first through holes 41 of the first light reflective sheet 40 are arranged so that one electrode 21 of the light source 20 faces one first through hole 41 . 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 holes 41 face each other. Here, the wiring substrate 30 is formed with third through holes 31 that penetrate the wiring layer 32 and communicate with the first through holes 41 respectively.
In the wiring board preparation step S2A, it is preferable to form the first through holes 41 of the first light reflective sheet 40 and the third through holes 31 of the wiring board 30 at the same time. That is, the first light reflective sheet 40A before the formation of the first through holes 41 is bonded to the surface of the wiring board 30A before the formation of the third through holes 31 on the side where the light emitting modules 102 are adhered to the bonding substrate 90A. By forming one through-hole facing the electrode 21 in each of the pair of positive and negative electrodes 21 of the light source 20, the formation of the first through-hole 41 and the formation of the third through-hole 31 are continuously performed. is preferred.

First, as in the first embodiment, as shown in FIG. 16A, a wiring substrate 30A is formed before the third through holes 31 are formed. Next, as shown in FIG. 16B, a bonded substrate 90A is formed by bonding the first light reflective sheet 40A before forming the first through holes 41 to the surface of the wiring substrate 30A to which 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 for each electrode 21 in the bonded substrate 90A. By forming the first through-holes 41 and the third through-holes 31 at the same time in this way, it is possible to improve the accuracy of alignment between the first light reflective sheet 40 and the wiring board 30 .

(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 together.
In the light emitting module bonding step S3A of the third embodiment, the light emitting module 102 is bonded to the wiring substrate 30 with the first light reflective sheet 40 interposed so that the electrodes 21 face the first through holes 41 . Adhesive resin is applied to the first light reflective sheet 40, and as shown in FIG. 17A, the electrodes 21 and the first through holes 41 are positioned to face each other, and the light emitting modules 102 are adhered. The illustration of the adhesive resin is omitted. It should be noted that the application of the adhesive resin can be omitted if, for example, an adhesive sheet having adhesive properties is used as the first light-reflecting sheet 40 .

Wiring board 30 to which light-emitting modules 102 have been adhered is viewed from the side to which light-emitting modules 102 are not adhered. The tip of the 1 through hole 41 is closed by the electrode 21 of the light source 20 . That is, the number of holes having the electrode 21 as the bottom and the third through hole 31 as the entrance is formed by the number of the electrodes 21 . A 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 reflecting sheet 40 .

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

(Modified example of light source)
Note that the light source is not limited to the configuration of the light source 20 already shown. For example, a light source that has a pair of positive and negative electrodes 21 on one side and emits blue or white light can be used. Modifications of the light source 20 will now 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, so that the light source 20A can emit white light. The light source 20A also has a first light adjustment member 24A on its upper surface and a light reflecting layer 24B on its lower surface, which is the surface on which the electrode 21 is provided. 20 A of light sources can reduce the light which reaches the wiring layer 32 by equipping the surface which has the electrode 21 with the light reflection layer 24B.

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 emit white light. Further, the light source 20B has a first light adjustment member 24A on its upper surface.
Translucent member 23A of light source 20B is arranged on light emitting element 22 . The side and bottom surfaces of the semiconductor laminate of the light emitting element 22 and the bottom surface of the translucent member 23A are covered with covering members 26, respectively. 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 materials used for the covering member 26 include silicone resin, epoxy resin, and acrylic resin. The covering member 26 contains a light diffusing material such as titania, barium titanate, aluminum oxide, or silicon oxide.

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

Further, as shown in FIGS. 18C and 18D, light sources 20C and 20D in which the light emitting element 22 is not sealed with the translucent member 23A and the covering member 26 can also be used as modifications of the light source 20. FIG. The light source 20</b>C has a first light adjustment member 24</b>C arranged on the top surface of the light emitting element 22 . Further, the light source 20D further includes a light reflection layer 24D on the surface of the light source 20C having the electrode 21. As shown in FIG.
As for materials 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. Moreover, a dielectric multilayer film may be used as the first light adjusting members 24A and 24C, or a film obtained by laminating a dielectric multilayer film and a metal film may be used.

(Modified example of method for forming 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 preformed light guide member (hereinafter referred to as a light guide plate) may be used. . The term “liquid” as used herein also includes paste. Also, although the modification of the first embodiment will be described here, it can be similarly applied to other embodiments.
As shown in FIG. 19A, the light guide plate 15a has, on its lower surface, a concave light source placement portion 11 sized to surround the light source 20, and covers the light source 20 so that the electrode 21 is exposed. The light source 20 is arranged on 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, the light guide member 15b can be formed by injecting a liquid resin so as to cover the upper surface of the light source 20 and hardening it. In this example, a light guide member composed of a light guide plate 15a1 and a light guide member 15b covers the light source 20 so that the electrode 21 is 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. Also, the light guide plate 15a1 may be a single layer or a multi-layer. For example, when the light guide plate 15a1 is composed of a plurality of layers, each layer can be laminated with an adhesive sheet. Any material can be used for such an adhesive sheet as long as it has translucency to the light emitted from the light source 20, and the same material as the light guide plate 15a1 is used so as to reduce the occurrence of an interface between layers. preferably used.

Alternatively, as shown in FIG. 19C, a light guide member 15c including a first light guide plate 15c1 and a 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 15 c 1 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, a 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 guide member 15c covers the light source 20 so that the electrode 21 is 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 a light guide plate is used, as shown in FIGS. 20C and 20D, the light reflecting member 75A is placed after the light guide plate 15a1 is placed on the first light reflecting sheet 40. FIG. In this case, part of the light-emitting module preparation process is changed. As an example, the light-emitting module preparation step S1B when using the light guide plate 15a1 will be described with reference to FIGS. 20A to 20F.
Similar to the light-emitting module preparation step S1 in the first embodiment, the first light-reflective sheet 40 having the first through-holes 41 formed thereon is aligned so that the first through-holes 41 and the electrodes 21 face each other. A light source 20 is arranged.
Subsequently, the light guide plates 15 a 1 are arranged on the first light reflecting sheet 40 so as to be adjacent to each other so that the light sources 20 are accommodated in the light source arrangement portion 11 . Then, a resin that is to be the material of the light guide member 15b is injected into the light source placement portion 11 inside the through hole so as to cover the light source 20, and is cured. A light guide member composed of light guide plate 15a1 and light guide member 15b covers light source 20 so that electrode 21 is exposed.
Subsequently, the material of the light reflecting member 75A is injected into the gap between the adjacent light guide plates 15a1 and hardened. Then, similarly to 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 assembly 155 of the light-emitting modules 105 is cut along the grid lines 75B of the light reflecting member 75A to be individualized. Although the second light adjusting member 60 in this embodiment covers the entire top surface of the light guide member 15b, part of the top surface of the light guide member 15b may be exposed from the second light adjusting member 60. .
In this way, when the light reflecting member 75A is formed by applying or injecting resin into the gap between the light guiding members and curing the resin, the light reflecting member 75A is formed along the shape of the outer surface of the light guiding member. be. 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.

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

(Modified example of wiring board)
Next, a modification of the wiring board will be described with reference to FIG. In this modification, wiring board 30B does not have 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 of the surface of the wiring layer 32 on the side of the light-reflective sheet 40 that face the first through holes 41 .

The insulating base material 34B has openings facing each of the first through holes 41 of the light reflective sheet 40, exposing the wiring layer 32B. The wiring layer 32B is thicker than other portions in the thickness direction of the wiring board 30B in the portions facing the first through holes 41 . Moreover, in this modification, the surface of the wiring layer 32B and the surface of the insulating base material 34B are substantially flush. A conductive member 50 is arranged between the wiring layer 32B and the electrode 21 with the first through hole 41 interposed therebetween. The wiring layer 32B in 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 thickness of the wiring layer 32B can be adjusted by the thickness of the conductive member 50. FIG.
In the manufacturing method of the planar light source using the wiring board 30B that does not have the third through holes 31, for example, in the light emitting module bonding process, the conductive member 50 is arranged on the wiring layer 32B before bonding the light emitting module. 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 through the first through hole 41 . Further, the contact points between the conductive member 50 and the wiring layer 32B are arranged at the portions facing the first through holes 41 on the surface of the wiring layer 32B on the side of the first light reflective sheet 40 .

Wiring board 30B does not need to form opening 37 in covering layer 36B. Therefore, it is not necessary to dispose the protective member 80 covering the opening 37 of the coating layer 36, and the number of steps in the manufacturing method can be reduced.
Modifications 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 like the light emitting module 101 of the second embodiment. In this case, the conductive member 50 is joined to the electrode 21 and the wiring layer 32B of the light source 20 using solder or the like. Note that the wiring layer may be a multi-layer instead of a single layer. The embodiment in which the wiring substrate has the third through-holes 31 and the modified example in which the wiring substrate does not have the third through-holes 31 can be similarly implemented even when the wiring layer is multi-layered.

REFERENCE SIGNS LIST 10 light guide member 11 light source placement portion of light guide member 15a light guide plate 20 light source 21 pair of positive and negative electrodes of light source 22 light emitting element of light source 23 translucent member of light source 24A light adjusting member of light source (first light adjusting member)
25 Area between electrodes on surface of light source having electrodes 26 Coating member of light source 30 Wiring board 31 Third through hole 32 Wiring layer of wiring board 34 Insulating base material of wiring board 36 Coating layer of wiring board 40 Light reflective sheet , first light reflective sheet 41 first through hole 45 second light reflective sheet 46 second through hole 50 conductive member 51 first conductive member 52 second conductive member 60 light adjustment member (second light adjustment member)
70 light reflecting member 75 modified example of light reflecting member 80 protective member 90 bonding substrate 100 light emitting module 150 aggregate of light emitting modules 200A part of planar light source 200, 300 planar light source

Claims (22)

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 electrode is exposed;
a wiring board having a wiring layer to which the electrodes are electrically connected;
a light reflective sheet interposed between the light guide member and the wiring board and having a first through hole facing each of the electrodes forming a pair of positive and negative electrodes;
the electrode and the wiring layer are electrically connected by a conductive member disposed through the first through hole ;
The light reflective sheet includes a first light reflective sheet having the first through hole and a second light reflective sheet having a second through hole facing the first through hole and in which the light source is arranged. and a planar light source. 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 electrode is exposed;
a wiring board having a wiring layer to which the electrodes are electrically connected;
a light reflective sheet interposed between the light guide member and the wiring board and having a first through hole facing each of the electrodes forming a pair of positive and negative electrodes;
the electrode and the wiring layer are electrically connected by a conductive member disposed through the first through hole;
The wiring board has third through-holes communicating with the first through-holes and penetrating the wiring layer, and a contact between the conductive member and the wiring layer is at least inside the third through-holes. A planar light source placed in the The light reflective sheet includes a first light reflective sheet having the first through hole and a second light reflective sheet having a second through hole facing the first through hole and in which the light source is arranged. 3. The planar light source according to claim 2, comprising: The wiring board has third through-holes communicating with the first through-holes and penetrating the wiring layer, and a contact between the conductive member and the wiring layer is at least inside the third through-holes. 2. The planar light source according to claim 1 , wherein the planar light source is arranged in 2. The planar light source according to claim 1 , wherein a contact point between the conductive member and the wiring layer is arranged at a portion facing each of the first through holes on the surface of the wiring layer on the light reflecting sheet side. 5. The method according to any one of claims 2 to 4, wherein a contact 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 facing the light reflective sheet. planar light source. 7. The conductive member comprises 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 1. 8. The planar light source according to any one of claims 1 to 7 , further comprising a light adjustment member arranged on the light guide member so as to face the light source through the light guide member. 9. The planar light source according to claim 1, further comprising a light reflecting member surrounding said light source. 10. The planar light source according to claim 1, wherein a region between the pair of positive and negative electrodes on the surface having the electrodes of the light source faces the light reflective sheet. 11. The planar light source according to claim 1, wherein a plurality of said light sources are arranged on said wiring board. 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; a light-emitting module preparation step of preparing a light-emitting module including a light-reflecting sheet;
a wiring board preparing step of preparing a wiring board having a wiring layer to which the electrodes are electrically connected;
a light-emitting module bonding step of bonding the light-emitting module to the wiring substrate;
A method of manufacturing a planar light source, comprising a connecting step of electrically connecting the electrode and the wiring layer via a conductive member arranged in the first through hole. 13. The surface according to claim 12 , wherein the connecting step electrically connects the electrode and the wiring layer using the conductive member pre-arranged in the first through hole of the first light reflective sheet. A method for manufacturing a shaped light source. A wiring board having a wiring layer to which the electrodes of the light source having a pair of positive and negative electrodes on one side are electrically connected is provided with a first through hole facing each of the electrodes forming the pair of positive and negative electrodes. 1 a wiring board preparation step of arranging a light reflective sheet so that the wiring layer and the first through hole face each other;
a second light reflecting sheet having a second through hole facing the first through hole and 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 preparing step of preparing a light emitting module in which the light source is arranged in the second through hole and 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 substrate with the first light reflective sheet interposed so that the electrode faces the first through hole;
A method of manufacturing a planar light source, comprising a connecting step of electrically connecting the electrode and the wiring layer via a conductive member arranged in the first through hole. 13. The connecting step includes arranging a contact point between the conductive member and the wiring layer in a portion of the wiring layer facing the first light reflective sheet and facing each of the first through holes. 15. The method of manufacturing a planar light source according to claim 14 . The wiring board preparing step includes forming, in the wiring board, third through-holes communicating with the first through-holes and penetrating the wiring layer,
15. The method of manufacturing a planar light source according to any one of claims 12 to 14, wherein in the connecting step, a contact between the conductive member and the wiring layer is arranged at least inside the third through hole. In the wiring board preparation step, the first light reflective sheet before the formation of the first through holes is bonded to the surface of the wiring board on the side of the wiring board to which the light emitting module is bonded. forming the first through-holes facing the electrodes one by one, and forming the third through-holes communicating with the respective first through-holes and penetrating the wiring layer; successively,
15. The method of manufacturing a planar light source according to claim 14 , wherein in the connecting step, a contact between the conductive member and the wiring layer is arranged at least inside the third through hole. 18. The connecting step according to claim 16 or 17 , wherein the contact between the conductive member and the wiring layer is arranged on the surface of the wiring layer opposite to the surface of the wiring layer facing the first light reflective sheet. A method for manufacturing a planar light source. 19. The planar light source according to any one of claims 12 to 18 , wherein the light-emitting module preparing step arranges a light adjustment member on the light guide member so as to face the light source through the light guide member. manufacturing method. 20. The method of manufacturing a planar light source according to any one of claims 12 to 19 , wherein the light emitting module preparing step further disposes a light reflecting member surrounding the light source. 21. The method of manufacturing a planar light source according to any one of claims 12 to 20, wherein a region between the pair of positive and negative electrodes on the surface having the electrodes of the light source faces the first light reflective sheet. . The light-emitting module adhering step arranges a plurality of the light-emitting modules on the wiring board.
22. The method of manufacturing a planar light source according to claim 12 .

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